| endothelium-dependent inhibition of ergonovine-induced contraction is impaired in porcine coronary arteries with regenerated endothelium. | the inhibitory effects of the endothelium against ergonovine-induced contraction were examined in isolated porcine coronary arteries under normal conditions and after endothelial regeneration. endothelium-dependent responses were examined in vitro in normal yorkshire pigs (n = 16) and in pigs that had undergone balloon endothelium removal of the left anterior descending coronary artery (lad) 4 weeks before the study (n = 10). the presence of a complete endothelial lining was confirmed histologic ... | 1989 | 2766515 |
| smokeless tobacco use among adolescents: correlates and concurrent predictors. | seventh grade students (n = 1539) from three regions of new york state were surveyed to determine the prevalence of smokeless tobacco use and its relationship to seven background variables, 13 substance use variables, and 19 psychosocial variables. significant correlations with smokeless tobacco use were found within each of these variable domains. concurrent predictors for each domain were determined using logistic regression analysis. the resulting three models were combined in a stepwise fash ... | 1989 | 2768485 |
| em autoradiographic study of the projections from the dorsal nucleus of the lateral lemniscus: a possible source of inhibitory inputs to the inferior colliculus. | the fine structure of the projection from the dorsal nucleus of the lateral lemniscus (dnll) to the inferior colliculus is examined in the cat. anterograde axonal transport of 3h-leucine and em autoradiographic techniques are used to label axonal endings from dnll. the primary finding is that axonal endings from dnll contain pleomorphic synaptic vesicles and make symmetrical synaptic contacts. this morphology is associated with inhibitory synapses. the projection from dnll is the source of appro ... | 1989 | 2768557 |
| determination of estradiol 2- and 16-alpha-hydroxylase activities in mcf-7 human breast cancer cells in culture using radiometric analysis. | using a radiometric assay the effects of estradiol upon the activity of estradiol 2- and 16 alpha-hydroxylases in mcf-7 human breast cancer cells in culture were studied. after 5 days of treatment and 36 h of withdrawal, incubation in the presence of either 2- or 16 alpha-tritiated substrate was carried out. estradiol (10 nm) significantly increased 16 alpha-hydroxylase activity (21%, p less than 0.01), while no effects on 2-hydroxylase activity was observed. treatment for 6 weeks caused a major ... | 1989 | 2770303 |
| [cardiovascular risk factors in children and adolescents in fuenlabrada: objectives, features of the population, design, participation, equipment, laboratory technics, and quality control]. | fuenlabrada is at the present time the most industrialized town placed at the south are of madrid. this population has some peculiar attractive characteristics from the epidemiologic point of view. perhaps the most important is that the majority of its inhabitants are immigrant from other depressed rural areas of the country, with a low socio-economic and cultural level. the new conditions of life could have changed the life expectation and the causes of morbidity and mortality of this populatio ... | 1989 | 2772364 |
| [chronic pyelonephritis in polycystic kidney]. | the characteristics of chronic pyelonephritis are studied in 37 patients out of a total of 53 patients with proved renal polycystosis. a group of 71 patients with chronic pyelonephritis selected at random are used as a control group. the frequency of chronic pyelonephritis among the patients with renal polycystosis is 69.8%. the difference between the mean age of the patients with renal polycystosis and chronic pyelonephritis and the patients with renal polycystosis without chronic pyelonephriti ... | 1989 | 2773465 |
| the mobilization of ferritin iron by liver cytosol. a comparison of xanthine and nadh as reducing substrates. | considerable evidence suggests that the release of iron from ferritin is a reductive process. a role in this process has been proposed for two hepatic enzymes, namely xanthine oxidoreductase and an nadh oxidoreductase. the abilities of xanthine and nadh to serve as a source of reducing power for the enzyme-mediated release of ferritin iron (ferrireductase activity) were compared with turkey liver and rat liver homogenates. the maximal velocity (vmax.) for the reaction with nadh was 50 times grea ... | 1989 | 2775199 |
| omega-hydroxyacid derivatives in the epidermis of several mammalian species. | 1. omega-hydroxyacids from the acylceramides and acylglucosylceramides of mammalian epidermis were examined by thin-layer and gas-liquid chromatography to determine their degree of unsaturation and chain-length distributions. the species examined included human (homo sapiens), pig (sus scrofa), mouse (mus musculus) and rat (rattus rattus). 2. within a species, the omega-hydroxyacids from the acylceramide and acylglucosylceramide were essentially identical. 3. the human omega-hydroxyacids proved ... | 1989 | 2776425 |
| repair of sublethal damage in two human tumor cell lines grown as multicellular spheroids. | multicellular tumor spheroids (mts) provide a suitable in vitro model to study radiation sensitivity of tumor cells. two cell lines of human origin, obtained from a neuroblastoma (nb-100) and a squamous cell carcinoma (hn-1), were exposed to graded doses (4-9 gy) of radiation with 18 mv photons. radiation was applied either as a single or as a split dose with an interval of 6 hr to determine the extent of sublethal damage repair. treated spheroids regrew at approximately the same growth rate as ... | 1989 | 2777647 |
| the sz mutant hamster: a genetic model of epilepsy or of paroxysmal dystonia? | attacks of sustained dystonic postures of limbs and trunk can be initiated by mild environmental stimuli in an inbred line of syrian hamsters. the trait is determined by an autosomal simple recessive genetic mutation, originally designated by the gene symbol sz, because the abnormal movements were thought to represent epileptic seizures. the attacks, which can be reproducibly initiated by placing the sz mutant hamsters in a new environment, begin with rapid twitches of the vibrissae, flattened e ... | 1989 | 2779593 |
| opening remarks of president fernando e. agrait on the occasion of the 50th anniversary of the cayo santiago macaque colony. | | 1989 | 2780954 |
| [toxoplasma gondii infections and oocyst shedding in domestic cats and the significance of this for the epidemiology and epizootiology of toxoplasmosis]. | because of the dissemination of oocysts the cat and other felines have a central position within toxoplasma gondii epidemiology and epizootiology. from 1984 to 1986, 267 cats between 2 months and 15 years old were serologically examined (sft) for toxoplasma antibodies. the rate of infection was 59.9 per cent. the infection rate of stray cats (72.5%) was significantly higher than that of domestic cats (40%). the high infection rate of herbivores results from behaviour of stray cats. in faeces of ... | 1989 | 2782669 |
| neurochemical profile of moclobemide, a short-acting and reversible inhibitor of monoamine oxidase type a. | moclobemide belongs to a new generation of short-acting, reversible, monoamine oxidase (mao) inhibitors. in vitro (rat brain homogenates) moclobemide inhibits mao-a selectively with lower potency than many of the reference mao inhibitors. however, when measured ex vivo in the rat, the potency of moclobemide is similar to that of reference compounds. in vivo the drug induces a dose-dependent, short-lasting (8-16 hr) and preferential inhibition of mao-a in the brain and both mao-a and mao-b inhibi ... | 1989 | 2783611 |
| neurochemical profile of moclobemide, a short-acting and reversible inhibitor of monoamine oxidase type a. | moclobemide belongs to a new generation of short-acting, reversible, monoamine oxidase (mao) inhibitors. in vitro (rat brain homogenates) moclobemide inhibits mao-a selectively with lower potency than many of the reference mao inhibitors. however, when measured ex vivo in the rat, the potency of moclobemide is similar to that of reference compounds. in vivo the drug induces a dose-dependent, short-lasting (8-16 hr) and preferential inhibition of mao-a in the brain and both mao-a and mao-b inhibi ... | 1989 | 2783611 |
| a novel calcium signalling response in the breast cancer cell line mda-468. | in the human breast carcinoma cell line mda-468 addition of epidermal growth factor (egf) is growth inhibitory. calcium signalling was investigated in this cell line using the calcium sensitive fluorescent probe indo-1. addition of egf to mda-468 cells resulted in a novel biphasic calcium response. in the first phase of the response egf raised calcium to levels significantly above basal. this was followed by a prolonged fall in calcium to levels significantly lower than original basal levels. th ... | 1989 | 2784677 |
| results of the flow cytometry actg quality control program: analysis and findings. | the aids clinical trial group's (actg) immunology committee was charged with initiating a quality control program for all laboratories participating in the actg program reporting flow cytometry data. forty-one laboratories were evaluated. this report defines the goals of this program and the subsequent findings after 19 send-outs were made. both hiv positive volunteer donors and normal age-matched donors were used. sample sets included both heparin and edta anticoagulated bloods. laboratories we ... | 1989 | 2785890 |
| co-localization of corticotropin-releasing factor- and enkephalin-like immunoreactivities in nerve cells of the rat hypothalamus and adjacent areas. | the co-localization of corticotropin-releasing factor (crf)- and enkephalin (enk)-like immunoreactivities in nerve cells of the rat hypothalamus and adjacent areas was investigated by the simultaneous application of immuno-beta-galactosidase staining and the peroxidase-antiperoxidase (pap) method to the same sections. crf-like immunoreactive cells were stained blue with immuno-beta-galactosidase staining and enk-like immunoreactive cells brown with the pap method. double-labeled cells with overl ... | 1989 | 2786446 |
| protection induced against acute bronchitis--the use of human and rat models to determine mechanisms of action of oral immunization with haemophilus influenzae. | | 1989 | 2786462 |
| human t lymphocytes possess a limited in vitro life span. | the t lymphocyte offers certain theoretical advantages over other available cell types for the study of aging. immunosenescence is a well-established part of, and may be directly relevant to, mammalian aging, and the t lymphocyte is well-characterized as to function, cell-surface antigen make-up, and other factors. however, prior efforts at studying in vitro aging of t cells have been hampered by poor reproducibility in doubling potential and the occurrence of a peculiar type of crisis. we have ... | 1989 | 2786475 |
| lymphokine-activated killer (lak) cells inhibit the clonogenic growth of human leukemic stem cells. | the effect of lymphokine-activated killer (lak) cells on the in vitro clonogenic capacity of acute myeloid leukemia (aml) blasts was investigated in a semisolid medium assay. the leukemic clonogenic capacity of 11 aml cases, selected on the basis of their ability to grow in vitro, was highly reduced following overnight preincubation with lak effectors. the degree of colony inhibition, which ranged between 66% and 98% (mean 83.8% +/- 11.4 sd), was quantitatively greater than by 51cr release, whic ... | 1989 | 2786477 |
| acute pathological effects on rats of orally administered wortmannin-containing preparations and purified wortmannin from fusarium oxysporum. | the pathological effects in rats of orally administered wortmannin, a mycotoxin produced by fusarium oxysporum, were studied. weanling rats were fed a wortmannin-containing fungal culture for 4 or 5 days, or were given by intragastric gavage a single, lethal dose of extracts of a wortmannin-containing fungal culture or pure toxin. haemoglobinuria, necrosis of lymphoid tissues and death occurred in rats fed the fungal culture. administration by gavage of extracts of the wortmannin-containing cult ... | 1989 | 2786490 |
| longitudinal study of the in vivo hprt mutant frequency in human t-lymphocytes as determined by a cell cloning assay. | the in vivo frequency of mutants resulting from mutation at the hprt locus in human t-lymphocytes can be determined by a cloning assay. this assay quantifies the frequency of 6-thioguanine-resistant (tgr) t-cells through growth of colonies in 96-well microtiter dishes. the reproducibility of the tgr mutant frequency values has now been assessed in a longitudinal study of six individuals (three male, three female, aged 22-33 years) employing 4-5 blood samples over a 26-37 week time period. clonin ... | 1989 | 2786809 |
| inhibition of enteropathogenic bacteria by human milk whey in vitro. | diarrhea caused by enteropathogenic bacteria is a leading cause of childhood mortality world-wide, particularly in less developed regions. breast-feeding has been advocated to protect infants and children from infectious illnesses. we examined the antibacterial activity of human whey in vitro against multiple strains of the following species of enteropathogenic bacteria, campylobacter jejuni, escherichia coli, salmonella typhimurium, shigella flexneri, shigella sonnei and vibrio cholerae, all is ... | 1989 | 2787902 |
| variceal hemorrhage as a consequence of spontaneous rupture of a pancreatic pseudocyst into the splenic vein. | we describe a case of a 68-yr-old man who died as a consequence of a massive bleed from esophageal varices. at autopsy, a pancreatic pseudocyst that communicated directly with the splenic vein was found. histology confirmed that material from the pseudocyst had embolized to the peripheral portal veins, occluding many of them. | 1989 | 2788993 |
| interleukin 1 in rheumatoid arthritis: potentiation of immune responses within the joint. | specific immunoassays were used to measure il-1 peptides in the serum and synovial fluid of patients with rheumatoid arthritis (ra) and in the serum of age-matched healthy controls. patients with ra had raised levels of both il-1 beta and il-1 alpha in their sera compared to controls. synovial fluid levels of il-1 beta significantly correlated with immunoreactive il-2 and soluble il-2 receptor (sil-2r). in addition, incubation of synovial fluid mnc with human recombinant (hr) il-1 caused a dose- ... | 1989 | 2789325 |
| estradiol-stimulated increases in uterine eosinophils and nuclear type ii estrogen-binding sites are prevented by pertussis toxin. | previous studies from several laboratories have demonstrated that estradiol treatment resulted in an increase in nuclear type ii binding sites. our previous data suggest that this increase was due to the estradiol-stimulated influx of circulating eosinophils. therefore, we suggested that the uterine nuclear type ii estrogen-binding sites were not of uterine origin. in this report we present further evidence to support this hypothesis. treatment of immature rats with estradiol resulted in the sti ... | 1989 | 2792007 |
| effects of soft contacts of differing thickness on corneal wound healing in rabbits. | this study was undertaken to determine the effects of thin (60 microns) and thick (240 microns) soft contact lenses of equal water content (70%) and power on nonlesioned and lesioned rabbit corneas. in one group of animals, corneas were not lesioned. thin lenses were placed on left corneas and thick lenses on right corneas. in a second group, lesions were made in both corneas. left corneas were covered with thin lenses and right corneas with thick lenses. post-treatment times were 8 hr and 24 hr ... | 1989 | 2793355 |
| detoxification of lithocholic acid. elucidation of the pathways of oxidative metabolism in rat liver microsomes. | the hydroxylation of lithocholic acid (3 alpha-hydroxy-5 beta-cholanoic acid) by adult male sprague-dawley rat liver microsomes supplemented with nadph was studied. metabolites were separated by a combination of thin-layer chromatography and high pressure liquid chromatography, both with and without prior methylation and acetylation of the samples. the resulting products were characterized by thin-layer, gas-liquid, and high pressure liquid chromatography by comparison with authentic bile acid s ... | 1989 | 2794781 |
| placental weights of normal and aneuploid early human fetuses. | placental and body weights were plotted for 252 normal human fetuses less than 600 gm and mean regressions and 95% prediction intervals were calculated. placentas from 62 aneuploid fetuses were compared to these standards. placenta to body weight ratios from 34 trisomy-21 fetuses were not reduced but those from 15 trisomy-18 fetuses were generally decreased. one of 5 trisomy-13 ratios was below the prediction interval. among 7 triploid fetuses the ratios were above the normal interval in 3 and b ... | 1989 | 2798268 |
| placental weights of normal and aneuploid early human fetuses. | placental and body weights were plotted for 252 normal human fetuses less than 600 gm and mean regressions and 95% prediction intervals were calculated. placentas from 62 aneuploid fetuses were compared to these standards. placenta to body weight ratios from 34 trisomy-21 fetuses were not reduced but those from 15 trisomy-18 fetuses were generally decreased. one of 5 trisomy-13 ratios was below the prediction interval. among 7 triploid fetuses the ratios were above the normal interval in 3 and b ... | 1989 | 2798268 |
| regional distribution and behavior of the subcutaneous tissue concerning selection and indication for liposuction. | the distribution of the fat tissue in the subcutaneous layer is described. since it has specific characteristics in each region of the human body, careful evaluation of the distribution before selecting patients for surgery is necessary. the subcutaneous tissue after an operation frequently demonstrates a thick and hard fibrosis which is evidence that liposuction should be performed in the lamellar layers. this type of fibrotic tissue in the subcutaneous areola layer often brings on irregulariti ... | 1989 | 2801296 |
| regional distribution and behavior of the subcutaneous tissue concerning selection and indication for liposuction. | the distribution of the fat tissue in the subcutaneous layer is described. since it has specific characteristics in each region of the human body, careful evaluation of the distribution before selecting patients for surgery is necessary. the subcutaneous tissue after an operation frequently demonstrates a thick and hard fibrosis which is evidence that liposuction should be performed in the lamellar layers. this type of fibrotic tissue in the subcutaneous areola layer often brings on irregulariti ... | 1989 | 2801296 |
| presence of cytoadhesins (iib-iiia-like glycoproteins) on human metastatic melanomas but not on benign melanocytes. | glycoproteins iib and iiia, a heterodimer complex, play a vital role in blood platelet aggregation and are members of a wide family of membrane receptors known as integrins or cytoadhesins. cellular interaction to extracellular matrix (ecm) adhesive proteins is mediated by integrins. certain tumor cells are known to interact with ecm and blood platelets in the process of metastasis. however, it is not known if tumor cells, compared with their normal counterparts, acquire iib-iiia-like receptors ... | 1989 | 2801613 |
| prevention of rectal cancer induced by n-nitrosobis(2-oxopropyl)-amine by exogenous testosterone in mrc rats. | rectal carcinogenicity of n-nitrosobis(2-oxopropyl)amine (bop) in male mrc wistar rats was shown to be inhibited by exogenous testosterone (t) when the hormone was given during, but not after, administration of the carcinogen. this effect was independent of the dose and frequency of bop, which was given either weekly for 20 weeks orally or daily for 3 days subcutaneously. since, except for prostatic cancer, the incidence and the patterns of other bop-induced tumors were not altered by t, this ho ... | 1989 | 2805225 |
| prevention of rectal cancer induced by n-nitrosobis(2-oxopropyl)-amine by exogenous testosterone in mrc rats. | rectal carcinogenicity of n-nitrosobis(2-oxopropyl)amine (bop) in male mrc wistar rats was shown to be inhibited by exogenous testosterone (t) when the hormone was given during, but not after, administration of the carcinogen. this effect was independent of the dose and frequency of bop, which was given either weekly for 20 weeks orally or daily for 3 days subcutaneously. since, except for prostatic cancer, the incidence and the patterns of other bop-induced tumors were not altered by t, this ho ... | 1989 | 2805225 |
| purification of a vasodilator-regulated phosphoprotein from human platelets. | cyclic-nucleotide-elevating vasodilators such as prostaglandin e1, prostacyclin, sodium nitroprusside and endothelium-derived relaxing factor inhibit both contraction of vascular smooth muscle cells and the aggregation of platelets at an early step of the activation cascade. previous studies from this laboratory [waldmann, r., nieberding, m. and walter, u. (1987) eur. j. biochem. 167, 441-448) established that in human platelets cyclic-nucleotide-elevating vasodilators stimulated a pattern of pr ... | 1989 | 2806262 |
| differential inhibition of downstream gene expression by the cauliflower mosaic virus 35s rna leader. | the effect of the 600 nucleotide-long camv 35s rna 5' leader sequence on the expression of downstream genes was analyzed both in plant protoplasts and in vitro. for transient expression studies in protoplasts derived from host and nonhost plants, the bacterial chloramphenicol acetyl transferase (cat) gene was fused to the initiation codon of orf vii. the leader sequence reduced cat expression two- to four-fold in protoplasts derived from three host species, but 10- to 50-fold in protoplasts deri ... | 1989 | 2815595 |
| differential inhibition of downstream gene expression by the cauliflower mosaic virus 35s rna leader. | the effect of the 600 nucleotide-long camv 35s rna 5' leader sequence on the expression of downstream genes was analyzed both in plant protoplasts and in vitro. for transient expression studies in protoplasts derived from host and nonhost plants, the bacterial chloramphenicol acetyl transferase (cat) gene was fused to the initiation codon of orf vii. the leader sequence reduced cat expression two- to four-fold in protoplasts derived from three host species, but 10- to 50-fold in protoplasts deri ... | 1989 | 2815595 |
| the measurement of secretory endometrial protein pp14 in serum from postmenopausal women receiving unopposed estrogen or continuously combined estrogen/progestogen. | a highly sensitive radioimmunoassay was developed to measure the low serum concentrations of the endometrial secretory placenta protein 14 (pp14) in postmenopausal women. the assay was established by selecting optimum reaction conditions for radioactive labelling of pp14, combined with simple procedures for the purification of the labelled pp14. the pp14 assay was used in 2 groups of healthy, early postmenopausal women blindly receiving either estrogen monotherapy (n = 20, placebo n = 25) or con ... | 1989 | 2816479 |
| on the estimation of pulmonary capillary pressure from arterial occlusion. | we have attempted to evaluate some approaches for estimating pulmonary capillary pressure from the transient pressure data obtained from the tip of the swanz-ganz catheter after inflation of the balloon. to this end experiments were carried out in anesthetized dogs in which pulmonary vasoconstriction was induced by infusion of histamine, serotonin, or norepinephrine or by hypoxia. in a group of closed chest dogs, the time course for the fall in the catheter tip pressure toward the wedge pressure ... | 1989 | 2817586 |
| [visualization of forensically important foreign bodies by direct roentgen magnification]. | the detection of foreign bodies of microscopic dimensions with radiographic techniques is limited by the size and density of the particle and the radiographic resolution. these restrictions can be of decisive value in case work. the high grade direct radiographic magnification technique was successfully used in preceding experiments. due to its 1 mu focal spot, this tube allows direct magnifications up to 250 times. in present studies, the advantages as well as the limitations of this new techni ... | 1989 | 2818477 |
| [visualization of forensically important foreign bodies by direct roentgen magnification]. | the detection of foreign bodies of microscopic dimensions with radiographic techniques is limited by the size and density of the particle and the radiographic resolution. these restrictions can be of decisive value in case work. the high grade direct radiographic magnification technique was successfully used in preceding experiments. due to its 1 mu focal spot, this tube allows direct magnifications up to 250 times. in present studies, the advantages as well as the limitations of this new techni ... | 1989 | 2818477 |
| identification of recessive mutations at human cancer loci. | | 1987 | 2820528 |
| in vivo measurements of tissue ph of the heart, brain, liver, spleen, and skeletal muscle following therapy of severe metabolic uraemic acidosis with infusion of bases: an experimental study on the limitation of the mellemgaard-astrup equation. | the intracellular tissue ph of the heart, brain, liver, spleen, and skeletal muscle of nephrectomized rats was determined in vivo from the distribution of 14c-labelled dmo (5,5-dimethyl-2-4-oxazolidinedione) following acute variation of arterial plasma ph (phe) by co2 inhalation or sodium bicarbonate administration in the range of phe 6.9-7.7, or following correction of severe metabolic uraemic acidosis with sodium bicarbonate or tris (hydroxymethyl) aminomethane (tham) infusion according to the ... | 1987 | 2820724 |
| atp synthesis by the (na+ + k+)-atpase in the absence of an ionic gradient. effects of organic solvent. | a 200-fold decrease in the pi concentration required for half-maximal phosphorylation of the (na+ + k+)-atpase is observed when 40% (v/v) dimethyl sulfoxide is added to the assay medium. the phosphoenzyme formed in the presence of dimethyl sulfoxide is able to transfer its phosphate to to form atp when concentrations of organic solvent and of na+, and is inhibited by ouabain. | 1987 | 2820794 |
| atp synthesis by the (na+ + k+)-atpase in the absence of an ionic gradient. effects of organic solvent. | a 200-fold decrease in the pi concentration required for half-maximal phosphorylation of the (na+ + k+)-atpase is observed when 40% (v/v) dimethyl sulfoxide is added to the assay medium. the phosphoenzyme formed in the presence of dimethyl sulfoxide is able to transfer its phosphate to to form atp when concentrations of organic solvent and of na+, and is inhibited by ouabain. | 1987 | 2820794 |
| frequency of is1-mediated molecular events in different members of the family enterobacteriaceae. | the numbers of chromosomal copies of the insertion sequence is1 in strains of salmonella typhimurium (0 to 8 copies), shigella sonnei (56 copies), and shigella flexneri (41 copies) isolated in mexico city, mexico, were similar to those reported for these genera isolated in other countries. of the 11 shigella strains studied, all carried several small plasmids; however, in only one of these strains did a small plasmid contain is1, is1 recombination, cointegrate formation mediated by is1 or by the ... | 1987 | 2822657 |
| induction of phr gene expression by irradiation of ultraviolet light in escherichia coli. | to measure the degree of phr gene induction by dna-damaging agents, the promoter region was fused to the coding region of the lacz gene in plasmid pmc1403. the new plasmids were introduced into escherichia coli cells having different repair capabilities. more efficient induction of phr gene expression was detected in a uvra- strain as compared with the wild-type strain. in addition, obvious induction was detected in uvra- cells treated by 4-nitroquinoline 1-oxide and mitomycin c. nalidixic acid, ... | 1987 | 2823069 |
| induction of phr gene expression by irradiation of ultraviolet light in escherichia coli. | to measure the degree of phr gene induction by dna-damaging agents, the promoter region was fused to the coding region of the lacz gene in plasmid pmc1403. the new plasmids were introduced into escherichia coli cells having different repair capabilities. more efficient induction of phr gene expression was detected in a uvra- strain as compared with the wild-type strain. in addition, obvious induction was detected in uvra- cells treated by 4-nitroquinoline 1-oxide and mitomycin c. nalidixic acid, ... | 1987 | 2823069 |
| morphological differentiation of cultured astrocytes is blocked by cadmium or cobalt. | the morphological transformation of astrocytes in primary culture from flat to process bearing is induced by cyclic adenosine monophosphate (camp). calcium currents in cultured astrocytes are also enhanced by camp. this correlation suggests the hypothesis that camp-induced calcium entry causes the morphological differentiation. the experiments reported here show that cadmium or cobalt, which block astrocyte calcium channels, also block the camp-induced morphological differentiation. these result ... | 1987 | 2823972 |
| isolation and characterization of is elements repeated in the bacterial chromosome. | shigella sonnei contains repetitive sequences, including an insertion element is1, which can be isolated as double-stranded dna fragments by dna denaturation and renaturation and by treatment with s1 nuclease. in this paper, we describe a method of cloning the is1 fragments prepared by the s1 nuclease digestion technique into phage m13mp8 rfi dna. several clones contained is1, usually with a few additional bases. we isolated and characterized five other repetitive sequences using this method. on ... | 1987 | 2824781 |
| effects of palindrome size and sequence on genetic stability in the bacteriophage phi x174 genome. | by inserting palindromes of varying length and sequence into a non-essential region of the bacteriophage phi x174 genome we have investigated the effect of palindrome size and sequence on their genetic stability. multimers of increasing size of the ecori linker ccgaattcgg (e), the bamhi linker ccggatccgg (b) or mixtures of both (e, b) were inserted into the pvuii site of a previously constructed bacteriophage strain phi x174 j-f ins6. the largest inserts that could be maintained in the genome wi ... | 1987 | 2824789 |
| dopamine denervation of the nucleus accumbens induces a selective increase in the number of delta-opioid binding sites. | selective lesions of dopamine (da) neurons of the nucleus accumbens were made in rats by local injections of 6-hydroxydopamine (6-ohda). seven days after 6-ohda, the binding affinities and capacities at mu-, delta- and kappa-opioid binding sites were determined in the nucleus accumbens by selective labelling techniques. 6-ohda pretreatment caused a significant increase in the number of delta-opioid binding sites (+30%) while the number of mu-, kappa- and total sites was not modified. the affinit ... | 1987 | 2825926 |
| dopamine denervation of the nucleus accumbens induces a selective increase in the number of delta-opioid binding sites. | selective lesions of dopamine (da) neurons of the nucleus accumbens were made in rats by local injections of 6-hydroxydopamine (6-ohda). seven days after 6-ohda, the binding affinities and capacities at mu-, delta- and kappa-opioid binding sites were determined in the nucleus accumbens by selective labelling techniques. 6-ohda pretreatment caused a significant increase in the number of delta-opioid binding sites (+30%) while the number of mu-, kappa- and total sites was not modified. the affinit ... | 1987 | 2825926 |
| genetic and physical characterization of trimethoprim resistance plasmids from shigella sonnei and shigella flexneri. | analysis of six shigella flexneri and four s. sonnei isolates with trimethoprim (tp) resistance from clinical cases in ontario has shown that, in all isolates, the tp resistance is mediated by gene(s) on conjugative, multiple antibiotic-resistance plasmids. the physical and genetic characterization of these plasmids revealed that there are three different tp resistance plasmids. one group, composed of all six s. flexneri plasmids, consists of plasmids which are about 70 megadaltons (mda) and inh ... | 1987 | 2825949 |
| murine cytomegalovirus-pseudomonas synergistic infections: comparison of virulent and attenuated virus. | the synergistic interactions between pseudomonas aeruginosa and virulent or attenuated murine cytomegalovirus (mcmv) were compared in vivo. virulent mcmv challenge at a dose of 5 x 10(5) pfu/mouse intraperitoneally, followed by intranasal superinfection with 5 x 10(6) cfu/mouse of pseudomonas aeruginosa after 48 h resulted in greater than 80% mortality, apparently owing to a failure of pulmonary clearance mechanisms. single infections, or the use of attenuated mcmv in synergistic infections, did ... | 1987 | 2825950 |
| limb specific connections of the cat magnocellular red nucleus. | afferent and efferent connections of the limb specific divisions of the cat magnocellular red nucleus (rnm) were traced using the bidirectional transport of wheatgerm agglutinin-horseradish peroxidase complex (wga-hrp). injection sites within forelimb or hindlimb rnm regions were identified by microelectrode recording and confirmed by the position of labeled rubrospinal terminals. additional injections into structures that project to, or receive input from, rnm confirmed the somatotopic organiza ... | 1987 | 2826551 |
| metabolic studies of a sustained galactose overload in rat. | in order to obtain an experimental model for studying inherited disorders of galactose metabolism in man, we administered to adult rats a diet supplemented with 50% of galactose during 38 days. the results showed clinical symptoms such as polyuria, polydipsia, growth retardation and bilateral cataract. the main biochemical features were an increase in the galactokinase and uridyltransferase activities in liver, an ubiquitous accumulation in tissues and a considerable urinary elimination of galac ... | 1987 | 2827561 |
| synthesis and biological activity of n-methylated analogues of neurokinin a. | limited conformational constraints have been introduced in the sequence of the c-terminal heptapeptide nka(4-10) by n-methylation of individual peptide bonds and the biological activities of the peptides thus obtained were evaluated on three in vitro preparations sensitive and quite selective for each of the naturally-occurring neurokinins, in order to assess the effect of n-methylation on receptor selectivity. the analogue methylated in position 7, namely [meval7] nka(4-10) shows some selectivi ... | 1987 | 2829053 |
| identification of tonin in brain and exocrine tissues and in the cell-free translation products encoded by the mrna of these tissues. | tissue-specific expression of the esteropeptidase tonin [ec 3.4.99.-] was investigated in rat brain, submandibular gland, pancreas and kidney. specific polyclonal and monoclonal antibodies to purified rat tonin from the submandibular gland have been developed and characterized and have been purified via a tonin-agarose affinity column. immunoreactive tonin was measured by a recently developed tonin direct radioimmunoassay using a rabbit tonin antiserum. resulting tonin levels were found to be 10 ... | 1987 | 2829829 |
| cytomegalovirus infection in burn patients. | we studied the seroepidemiology of cytomegalovirus (cmv) infection in 59 patients with thermal injuries. among the 31 patients who were initially cmv seronegative, seven (22.5%) seroconverted. patients who seroconverted had longer hospital stays (mean, 27 +/- 23.9 days v 14.9 +/- 8.8 days in seronegative patients [p = 0.03]) and they received more blood products (mean, 10.7 +/- 17.9 units v 1.8 +/- 2.8 units [p = 0.02]) than patients who remained seronegative. among 18 patients who were initiall ... | 1987 | 2830289 |
| development and testing of invasion-associated dna probes for detection of shigella spp. and enteroinvasive escherichia coli. | genetic determinants of the invasive phenotype of shigella spp. and enteroinvasive escherichia coli (eiec), two common agents of bacillary dysentery, are encoded on large (180- to 210 kilobase), nonconjugative plasmids. several plasmid-encoded antigens have been implicated as important bacterial ligands that mediate the attachment and invasion of colonic epithelial cells by the bacteria. selected invasion plasmid antigen (ipa) genes have recently been cloned from shigella flexneri serotype 5 int ... | 1988 | 2830310 |
| three distinct forms of type 2a protein phosphatase in human erythrocyte cytosol. | two type 2a protein phosphatases, phosphatases i (mr = 180,000) and iii (mr = 177,000), were purified to near homogeneity from human erythrocyte cytosol. phosphatase i was composed of alpha (34 kda), beta (63 kda), and delta (74 kda) subunits in a ratio of 1:1:1. phosphatase iii comprised alpha, beta, and gamma (53 kda) subunits in the same ratio. heparin-sepharose column chromatography converted most of phosphatase i and 20% of phosphatase iii into alpha 1 beta 1 which were indistinguishable fr ... | 1988 | 2831201 |
| apolipoprotein e-rich hdl binding to liver plasma membranes in copper-deficient rats. | copper deficiency in rats raises plasma cholesterol concentration while reducing live cholesterol concentration. one consequence of this cholesterol redistribution is the accumulation of a large high-density lipoprotein (hdl) particle rich in apolipoprotein e (apo e). the purpose of this study was to determine, using an in vitro binding assay, if the interaction of apo e-rich hdl with hepatic lipoprotein binding sites may be affected by copper deficiency. male sprague-dawley rats were divided in ... | 1988 | 2831541 |
| flanking and internal regions of chromosomal genes mediating aerobactin iron uptake systems in enteroinvasive escherichia coli and shigella flexneri. | we have investigated the presence of the aerobactin system and the location of the aerobactin genes in enteroinvasive strains of escherichia coli. also, we cloned the aerobactin region and its flanking sequences from the chromosome of a strain of shigella flexneri and compared the molecular organization of the aerobactin genes in the two genera. of the 11 enteroinvasive e. coli strains studied, 5 possessed the aerobactin genes, which were located on the chromosome in each case. these strains pro ... | 1987 | 2832521 |
| analysis and isolation of cytomegalovirus dna by field inversion gel electrophoresis. | high molecular weight human cytomegalovirus (cmv) dna was isolated from agarose-embedded infected human diploid cells by employing field inversion gel electrophoresis. a high yield of cmv dna molecules was obtained within 1 week of infecting the cell culture. labelling of the viral dna with biotin by nick translation enabled the detection of cmv-infected cells in sections of paraffin-embedded human adrenal gland by in situ hybridization. | 1988 | 2832532 |
| analysis and isolation of cytomegalovirus dna by field inversion gel electrophoresis. | high molecular weight human cytomegalovirus (cmv) dna was isolated from agarose-embedded infected human diploid cells by employing field inversion gel electrophoresis. a high yield of cmv dna molecules was obtained within 1 week of infecting the cell culture. labelling of the viral dna with biotin by nick translation enabled the detection of cmv-infected cells in sections of paraffin-embedded human adrenal gland by in situ hybridization. | 1988 | 2832532 |
| viruses in sewage waters during and after a poliomyelitis outbreak and subsequent nationwide oral poliovirus vaccination campaign in finland. | during an outbreak of paralytic poliomyelitis in finland in 1984 and 1985 the widespread circulation of the causative wild-type serotype 3 poliovirus in the population was documented by demonstrating the virus in sewage water specimens in 13 different locations in the greater helsinki district and in 13 other cities or towns all over the country. after the nationwide campaign with oral poliovirus vaccine in 1985, poliovirus serotypes 2 and 3 were readily isolated from sewage waters for up to 2 m ... | 1988 | 2833160 |
| monoclonal antibodies with neutralizing activity segregate isolates of bovine viral diarrhea virus into groups. brief report. | isolates of bovine viral diarrhea (bvd) virus were differentiated by monoclonal antibodies (moabs) reactive with the 56 kd viral polypeptide. patterns of neutralizing activity of the moabs indicate that multiple epitopes are involved in virus neutralization. | 1988 | 2833200 |
| "sub-threshold neoplastic states" created in transgenic mice. | several possible scenarios are already suggested by the first series of studies in which a high risk situation with respect to malignant diseases was artificially created by introducing oncogenes in the mouse germ line. only in exceptional cases was the expression of the transgene followed in an obligatory way by cancerous proliferation. the usual situation appears now to be that somatic cells expressing the transgene have only a higher probability than normal cells of undergoing a subsequent tr ... | 1987 | 2835726 |
| "sub-threshold neoplastic states" created in transgenic mice. | several possible scenarios are already suggested by the first series of studies in which a high risk situation with respect to malignant diseases was artificially created by introducing oncogenes in the mouse germ line. only in exceptional cases was the expression of the transgene followed in an obligatory way by cancerous proliferation. the usual situation appears now to be that somatic cells expressing the transgene have only a higher probability than normal cells of undergoing a subsequent tr ... | 1987 | 2835726 |
| virulence-associated genetic regions comprising 31 kilobases of the 230-kilobase plasmid in shigella flexneri 2a. | by random transposon tn5 insertions, we previously identified six virulence-associated sali fragments, b, d, f, g, h, and p, in the 230-kilobase plasmid pmysh6000 of shigella flexneri 2a. in this study, we analyzed the sites of 134 independent tn5 insertions on four contiguous sali fragments, b, p, h, and d, of pmysh6000 and identified five virulence-associated regions; four were associated with inducing a positive sereny test (ser), invasion into epithelial cells (inv), binding to congo red (pc ... | 1988 | 2836357 |
| molecular basis of sindbis virus neurovirulence in mice. | we examined a variety of strains of sindbis virus for the genetic changes responsible for differences in neurovirulence in mice. sv1a (a low passage of the ar339 strain of sindbis virus), a neuroadapted sindbis virus (nsv), and two laboratory strains of sindbis virus (hrsp and toto1101) were examined. nsv causes severe encephalomyelitis with hind-limb paralysis and high mortality after intracerebral inoculation in weanling mice. in contrast, sv1a causes only mild, nonfatal disease in weanling mi ... | 1988 | 2836615 |
| development of an auxotrophic oral live shigella flexneri vaccine. | an oral live attenuated shigella flexneri vaccine candidate strain was constructed by making it auxotrophic and dependent on aromatic metabolites not available in mammalian tissues. an arod gene of escherichia coli k12 strain nk 5131, inactivated by insertion in it of the tn 10 transposon, was transduced using phage p1 into a virulent s. flexneri serotype y strain (sfl 1) isolated from a patient with bacillary dysentery. one of the transductant strains sfl 114 was found to invade hela cells in v ... | 1988 | 2838986 |
| the structure of the human skin fibroblast collagenase gene. | genomic clones containing the complete gene encoding human fibroblast interstitial collagenase were isolated from a lambda phage human dna library. the gene is comprised from 10 exons and spans 8.2 kilobase pairs. we have mapped the relative positions and determined the dna sequence of all the exon/intron borders of the gene. the organization of the human interstitial collagenase gene is very similar to that of rabbit collagenase and of two other extracellular matrix (ecm) metalloproteases: rat ... | 1988 | 2839503 |
| the structure of the human skin fibroblast collagenase gene. | genomic clones containing the complete gene encoding human fibroblast interstitial collagenase were isolated from a lambda phage human dna library. the gene is comprised from 10 exons and spans 8.2 kilobase pairs. we have mapped the relative positions and determined the dna sequence of all the exon/intron borders of the gene. the organization of the human interstitial collagenase gene is very similar to that of rabbit collagenase and of two other extracellular matrix (ecm) metalloproteases: rat ... | 1988 | 2839503 |
| cloned mouse lymphocytes permit analysis of somatic mutations that occur in vivo. | as part of our mouse model of somatic mutation, we have begun to characterize spontaneously occurring hypoxanthine phosphoribosyltransferase (hprt) -deficient mouse lymphocytes. lymphocytes were cloned by in vitro exposure of spleen cells from male c57b1/6 mice to the mitogen concanavalin a, conditioned medium containing lymphocyte growth factors, and thioguanine (tg), in a limiting dilution assay. the 17 tg-resistant clones recovered were all highly deficient in hprt activity and were found by ... | 1987 | 2842875 |
| selective induction of chromosomal gene expression by human cytomegalovirus. | during permissive infection, human cytomegalovirus (hcmv) increases the activities of certain cellular enzymes. in this report, we show that induction of these cellular genes occurs at the level of rna. the abundance of several additional growth-regulated cellular transcripts in hcmv-infected human foreskin fibroblasts (hff) was also compared to that in serum-stimulated hff cells. hcmv infection of hff cells resulted in increased abundance of ornithine decarboxylase, thymidine kinase, heat-shock ... | 1988 | 2842946 |
| detection of leukotriene b4 in cardiac tissue and its role in infarct extension through leucocyte migration. | the main left coronary artery of rats was ligated near its origin under light ether anaesthesia and the infarction observed for 48 h. the ischaemic area was determined after an intravenous injection of pontamine sky blue dye 1 h before induction of cardiac arrest with potassium chloride. the unstained area (true ischaemic area) decreased with time to 27.1% of the left ventricle at 48 h, whereas the intensely stained area between the normal and the true ischaemic areas increased with time, sugges ... | 1988 | 2844405 |
| prenatal diazepam exposure affects beta-adrenergic receptors in brain regions of adult rat offspring. | the postnatal development of [3h]dihydroalprenolol binding to beta-adrenergic receptors has been studied in frontal cortex, cerebellum, striatum, and hypothalamus of the rat after prenatal and perinatal exposure to diazepam. dams were injected subcutaneously with single daily doses of 1 mg of diazepam/kg from day 7 to 20 of gestation or from day 15 of gestation to day 6 after birth. prenatal exposure had no effect on litter size or length of gestation or on the postnatal development of body and ... | 1988 | 2844991 |
| effects of light- and dark-rearing on the postnatal development of gaba receptor sites in the chick optic lobe. | to investigate the ability of gaba receptor sites to undergo environmental-dependent plastic changes, the postnatal developmental pattern of gaba receptors was studied under different levels of light stimulation, i.e. normal-, light- and dark-rearing. at hatching the specific binding of [3h]gaba was 1.74 +/- 0.36 pmol/optic lobe. in normally reared chicks the number of gaba binding sites showed a transient increase with the highest value at the 6th day (7.0 +/- 1.32 pmol/optic lobe). this value ... | 1987 | 2845719 |
| [bovine herpesvirus type 2 infection]. | | 1988 | 2845879 |
| localization of plasmid loci necessary for the entry of shigella flexneri into hela cells, and characterization of one locus encoding four immunogenic polypeptides. | we have previously cloned a 44 kb fragment from the virulence plasmid of shigella flexneri serotype 5 strain m90t which is capable of restoring invasiveness to an avirulent, plasmidless mutant. this report presents a genetic and physical analysis of tn5 mutations in recombinant clone phs4108. tn5 mutagenesis allowed identification of at least five regions implicated in the entry phenotype. these regions were located on a 20 kb portion of phs4108. expression of the insertion mutants was studied b ... | 1987 | 2846749 |
| metabolic events mediating early killing of host cells infected by shigella flexneri. | j774, a continuous macrophage cell-line, was infected by m90t, an invasive isolate of shigella flexneri serotype 5 and bs176, its non invasive derivative--which does not harbor the 220 kbase virulence plasmid pwr100. killing of host cells by intracellular m90t, commenced one hour after infection and was completed by 4 hours. intracellular bs176 did not kill cells during the same period. cell protein biosynthesis was totally inhibited by both strains within 2 hours of infection thus indicating th ... | 1987 | 2848171 |
| interaction between bambuterol and physostigmine: aspects on cholinesterase inhibition and neuromuscular transmission in the smooth and skeletal muscles of the guinea-pig. | bambuterol, the bis-dimethyl carbamate prodrug of terbutaline, and physostigmine were examined with respect to their ability to interfere with the neuromuscular transmission in an isolated vagus nerve-trachea preparation, a phrenic nerve-diaphragm preparation and the transmurally stimulated extensor digotorum longus (edl) isolated from the guinea-pig. physostigmine increased the contractile response of the trachea to stimulation of the vagus nerve. bambuterol had an opposite effect in this respe ... | 1988 | 2848230 |
| comparisons of the pathogenicity of long and short fibres of chrysotile asbestos in rats. | long-term inhalation and intraperitoneal injection studies were undertaken with laboratory rats treated with a specially prepared short-fibre sample of canadian chrysotile asbestos. this was compared, at an equal mass dose, to dust generated from the same chrysotile batch so as to contain the highest possible number of long fibres. the long-fibre cloud contained roughly five times more fibres greater than 5 micron in length as seen by phase contrast optical microscopy (pcom). for increasing leng ... | 1988 | 2848570 |
| expression of env sequences of the bovine leukemia virus (blv) in the yeast saccharomyces cerevisiae. | dna sequences of the envelope (env) gene of the bovine leukemia virus (blv) were expressed in the yeast saccharomyces cerevisiae. two yeast promoters, the repressible pho5 promoter and the constitutive pgk promoter, were used to construct four expression plasmids comprising either a sequence of the surface antigen gp51 or a (gp51 + gp30) sequence. the expressed heterologous gene products were characterized by western blot analysis and competitive radioimmunoassay. by means of northern blot analy ... | 1988 | 2849260 |
| peripheral neuropathy in elderly cba mice. | a late-onset peripheral neuropathy in a mouse with a wider progressive neurological disorder is morphologically characterized for comparison with late life human neuropathies. preliminary studies indicate the presence of a proximal, predominantly motor, axonopathy in the mouse model. | 1988 | 2849396 |
| salience and the effects of cs preexposure on aversion conditioning. | rats (n = 84) received preexposure to distilled water or to one of two differently salient flavors, 5.0% casein or 10.0% sucrose, casein being the more salient. each preexposure group then received aversion conditioning to a 5.0% casein or a 10.0% sucrose cs. aversion effects were reliably more enduring to casein than to sucrose. relative to water-preexposed groups, preexposure to casein attenuated aversion effects to the casein cs reliably less than preexposure to sucrose attenuated aversion ef ... | 1988 | 2849411 |
| similarity between human retinoic acid receptor and escherichia coli homoserine kinase. | | 1988 | 2849427 |
| a new class of free radical scavengers reducing adriamycin mitochondrial toxicity. | beef heart mitochondria were incubated with adm and nadh. an adriamycin semiquinone radical was detected using esr spectroscopy. the semiquinone radical production rate is decreased upon addition of a scavenger (ad 20) in the reaction medium. nmri mice were treated with ad 20 (70 mg/kg, i.p.) 15 min prior adm injection (20 mg/kg, i.p.) or with adm alone. heart mitochondria were isolated 48 hr later. the enzymatic activities of complex i-iii and complex iv of the mitochondrial respiratory chain w ... | 1988 | 2849451 |
| the cupric site in nitrous oxide reductase contains a mixed-valence [cu(ii),cu(i)] binuclear center: a multifrequency electron paramagnetic resonance investigation. | multifrequency electron paramagnetic resonance (epr) spectra of the cu(ii) site in nitrous oxide reductase (n2or) from pseudomonas stutzeri confirm the assignment of the low field g value at 2.18 consistent with the seven line pattern observed at 9.31 ghz, 10 k. s-band spectra at 20 k are better resolved than the x-band spectra recorded at 10 k. the features observed at 2.4, 3.4, 9.31 and 35 ghz are explained by a mixed-valence [cu(1.5)..cu(1.5)] s = 1/2 species with the unpaired electron deloca ... | 1988 | 2849565 |
| human rotavirus infection enhances invasiveness of enterobacteria in ma-104 cells. | to study the interaction between common pathogens causing infectious diarrhea in humans, ma 104 cell cultures were infected with human rotavirus and salmonella typhimurium or shigella flexneri or enteroinvasive escherichia coli (eiec) concomitantly. when ma-104 cells were preinfected with human rotavirus, invasiveness of s. typhimurium was significantly enhanced. the enhancement was evident after 48 h of virus preincubation. at this time virus specific antigens were demonstrated in the cell cult ... | 1988 | 2850823 |
| endotoxin-induced uveitis in rats: morphological and biochemical study. | inflammation induced by systemic injection of endotoxin can be a good model for endogenous uveitis since ocular inflammation is induced without manipulating the eye. we carried out morphological and biochemical studies in lewis rats to evaluate the breakdown of the blood-ocular barrier following injection of endotoxin (1 mg/rat) in footpads. vasodilation was observed as early as 3 hours and became maximum at 18-24 hours after the injection. unlike in the eye, no inflammatory changes were observe ... | 1988 | 2853240 |
| in vitro activity of azithromycin (cp-62,993), a novel macrolide, against enteric pathogens. | azithromycin (cp-62,993 [9-deoxy-9a-methyl-9a-aza-9a-homoerythromycin]) is a novel macrolide antimicrobial. in this study the in vitro activity of cp-62,993 has been determined against selected enteropathogens, including clostridium difficile, and compared with that of erythromycin. mics were determined using an agar incorporation technique in mueller-hinton medium, containing saponin-lysed horse blood at a final concentration of 10% v/v, with an inoculum of 10(4) cfu. cp-62,993 was considerably ... | 1988 | 2854515 |
| genetic analysis of the plasmid region controlling virulence in yersinia enterocolitica 0:9 by mini-mu insertions and lac gene fusions. | enteropathogenic strains of yersinia enterocolitica harbor a virulence plasmid (pyve plasmid) of 70 kilobases (kb) which specifies, at 37 degrees c, a calcium requirement for growth, autoagglutinability, resistance to the bactericidal activity of human serum, and the expression of outer membrane proteins (omp). some mutations suppress the calcium requirement for growth while others make the bacteria unable to grow at 37 degrees c, even in the presence of calcium. to analyse the genes involved in ... | 1986 | 2854600 |
| striatal synaptosomal dopamine synthesis: evidence against direct regulation by an autoreceptor mechanism. | regulation of the rate-limiting step in dopamine (da) synthesis was estimated in striatal synaptosomes by measuring the rate of hydroxylation of l-4-[3h]phenylalanine, a substrate of tyrosine hydroxylase (th). da inhibited hydroxylation with an ic50 of 0.2 microm. the concentration-response curve of da-induced inhibition was not affected by the presence of 1 microm chlorpromazine, a phenothiazine da antagonist. sulpiride and haloperidol, da antagonists of the benzamide and butyrophenone classes ... | 1985 | 2859213 |
| prolactin and its involvement in fluid regulation in the bovine. | plasma prolactin (prl) concentrations, osmolality, water consumption, feed intake, urine excretion, and fecal water output were determined in twelve steers of 3 breeds exposed to 5 feed and water regimes. breed differences were found in water intake and plasma prl concentrations when feed and water were ad lib., however, during any of the other 4 treatments, responses were similar between breeds. during dehydration and feed restriction, water intake, urine, fecal water, and plasma prolactin decr ... | 1985 | 2859961 |
| effects of excitatory amino acids on calcium transport by brain membranes. | the effect of excitatory amino acids on the uptake of 45ca was studied in crude mitochondrial (p2) fractions prepared from mouse brain. l-glutamate stimulated calcium uptake, but this action was not shared by other amino acids including d-glutamate, l-aspartate, n-methyl-aspartate or kainate. the glutamate-stimulated calcium uptake was, however, blocked by inhibitors of glutamate dehydrogenase, such as d-glutamate, glutarate and triiodothyronine. subcellular fractionation demonstrated that the u ... | 1985 | 2860953 |
| chemotaxis by entamoeba histolytica. | a micropore membrane procedure to assay taxis by entamoeba histolytica is described and the results of studies of responses to a variety of soluble substances, bacteria, an rat colon washings using this procedure are reported. trophozoites migrated in blind well chambers through 8-micron pore size polycarbonate membranes but not nitrocellulose membranes up to 12 micron pore size. amoebae were attracted toward fresh axenic culture medium (tyi-s), an enzymatic hydrolysate of casein (trypticase), a ... | 1985 | 2861283 |