effect of quantity and quality of igg antibodies on blocking of allergenic histamine release in a study of the protective role of igg antibodies in allergen injection therapy, serum antibodies to timothy grass allergens were raised in rabbits and tested for inhibition of histamine release from basophils of grass pollen-sensitive human subjects. rabbit sera were not inhibitory until late in the immune response when large amounts of relatively low affinity igg antibodies were detected by primary binding. inhibition of histamine release by late sera required preincubation of allergen and a ...197984798
fatal adenovirus infection with misleading positive serology for infectious mononucleosis.symptoms and serological tests in a 19-year-old man with pneumonia indicated that he had infectious mononucleosis. adenovirus type 7 was demonstrated in the lung by electron microscopy and was cultured from the liver, lung, lymph-nodes, and kidney.197984950
safety of hepatitis-b vaccines containing intact 20 nm particles. 197985121
the patterns and distribution of euchrysine-binding grains in nonstimulated human peripheral t and non-t lymphocytes. 197986386
effects of antiprostatic agents on 5alpha-dihydrotestosterone binding to rat hypophyseal and hypothalamic cytosol macromolecules.the binding of 5alpha-dihydrotestosterone to the hypophyseal and hypothalamic cytosol macromolecules prepared from castrated male rats was observed. the effects of antiprostatic agents on 5alpha-dihydrotestosterone binding to both hypophyseal and hypothalamic cytosol macromolecules was examined. cyproterone acetate and chlormadionone acetate showed the significant inhibiting effects on 5alpha-dihydrotestosterone binding to 7-8 s macromolecules of cytosol from both hypophysis and hypothalamus. sc ...197986441
treatment of mammalian ova for the demonstration of nucleoprotein structures. 197986485
binding studies with antibodies having phosphorylcholine specificity and fragments derived from their homologous streptococcus pneumoniae type 27 capsular polysaccharide.the capsular polysaccharide from streptococcus pneumoniae type 27 (s-27) has been fragmented into oligosaccharides by controlled degradations. binding of these derived small ligands with heterogeneous rabbit anti-s-27 antibody of selected phosphorylcholine affinity indicates that a major immunodeterminant of s-27 is the phosphorylcholine moiety, but that these anti-pc. antibodies are also capable of binding to the polysaccharide backbone from which the p.c. has been removed.197987460
guinea pig transfer factor: restriction of macrophage migration inhibitory activity to extraordinary dilution confirmed with demonstration of diminished potency of stored preparations. 197988292
detection of adenovirus by enzyme-linked immunosorbent assay.a solid-phase direct enzyme-linked immunosorbent assay (elisa) was developed for the detection of adenovirus antigen in extracts of infected cells by using antihexon serum. results with simulated clinical specimens consisting of normal nasal wash specimens seeded with varying concentrations of adenovirus type 5 showed that antigen could be detected in extracts of hep-2 cell cultures inoculated with 10(2.5) 50% tissue culture infective doses (tcid50) and 10(1.5) tcid50 after 2 and 4 days of incub ...197988457
the influenza virus: antigenic composition and immune response.the architecture and chemical composition of the influenza virus particle is described with particular reference to the protein constituents and their genetic control. the dominant role in infection of the surface proteins - haemagglutinins and neuraminidases - acting as antigens and undergoing variation in time known as antigenic drift and shift is explained. the immuno-diffusion technique has illuminated the interrelationships of the haemagglutinins of influenza a viruses recovered over long p ...197988726
amylase levels in the tissues and body fluids of the domestic cat (felis catus).1. the amylase activities of serum, liver, pancreas, submaxillary and parotid glands, saliva, duodenum, colon, lung, heart, spleen, kidney and skeletal muscle of the domestic cat, were determined. 2. as in most mammals, the highest amylase content was found in the pancreas. levels in saliva and salivary glands were very low. 3. amylase activities of the serum, liver and pancreas have an optimum ph 7.0-7.5. 4. amylases of serum, liver and pancreas were inactivated by removal of chloride and these ...197995689
[the mechanism of adenine nucleotide biosynthesis from adenine in corynebacterium species].the mechanism of atp biosynthesis from adenine was studied on the cell-free extract of corynebacterium species that produces atp from exogenous adenine, using labeled substrates. as a source of the ribosyl component of the atp molecule, phosphoribosyl pyrophosphate (prpp) and ribose-5-phosphate (p5p) were tested. the experiments with prpp showed adenine phosphoribosyl transferase (ec activity in the extract responsible for the amp formation from prpp and adenine. the minimal reaction mi ...197995886
hematological data of the laboratory-maintained bonnet (macaca radiata) and the langur (presbytis entellus entellus) monkeys. 197895998
ultrastructural localization of calcium around the membrane of the surface connected system in the human platelet.the localization of calcium in the membrane system of human platelets was determined by ultrahistochemical methods equipped with an electron probe x-ray microanalyzer. after potassium oxalate-glutaraldehyde treatment large amounts of electron opaque precipitates were observed around the membrane of the surface connected system. electron probe x-ray microanalysis clearly defined that the precipitates were composed of calcium oxalate. the localization of calcium on the membrane of the surface conn ...197896043
the relative biological effectiveness of pions in the acute response of human skin. 197796068
endemic pneumocystis carinii in a marmoset colony. 197896156
induction of arylhydrocarbon hydroxylase and udp glucuronosyl transferase by pcb in hepatic cell cultures.the purpose of the investigation was to derive a hepatic cell line to be used in induction studies of drug metabolizing enzymes. two pure cell lines were isolated from primary liver cell cultures, one with an epithelial-like appearance, the other with a fibroblast-like appearance. the specific activities of arylhydrocarbon hydroxylase (ahh) and udp glucuronosyl transferase (udpgt) were greater in hepatocyte cultures than in primary cultures or in fibroblast cultures. pcb enhanced the activity of ...197898133
[immuno-electro-diffusion on cellulose acetate membrane for serological testing in human malaria (author's transl)].an immuno-electro-diffusion assay for human malaria, using cellulose acetate gel, is described. more than 3500 sera have been tested by this method, which proved very useful for epidemiology since 400 sera a day can be tested by one person, with simple equipment. its sensitivity compared well to the ifa test, although the antibodies revealed are quite different. a constnat precipitin line appeared, against 56 degrees c labile antigens, in sera of subjects infected by p. falciparum, and up to 8 o ...197898748
the effect of housing and gender on morphine self-administration in determine the effect of housing conditions on morphine self-administration, rats isolated in standard laboratory cages and rats living socially in a large open box (8.8 m2) were given morphine in solution (0.5 mg/ml) as their only source of fluid for 57 days. they were then exposed to a series of 3-day cycles previously shown by nichols et al. (1956) to increase self-administration of morphine in caged rats. on morphine/water choice days late in the period of forced consumption, between the n ...197898787
guinea pig immunoglobulin light chain isotypes. i. separation of kappa and lambda chains and the identification of three isotypes of the lambda chain constant homology region.the separation of intact kappa chain and two fragments comprising lambda (lambda) chain from immunoglobulin light chain pools isolated from strain 13 guinea pigs is achieved by cyanogen bromide digestion and gel filtration before and after reductive clevage of disulfide bonds. the smaller lambda chain fragment derives from the original carboxyl-terminus of lambda chain. the partial sequence of component tryptic and thermolytic peptides of this thirty-nine residue fragment allowed its complete se ...1978103729
congenital defects due to hyperthermia. 1978104560
ophthalmic features of chromosome deletion 4p- (wolf-hirschhorn syndrome).by using the giemsa banding technique we identified three patients with chromosome deletion 4p-. all had anterior segment anomalies, exotropia, blepharoptosis, antimongoloid palpebral fissures, hypertelorism, and disk abnormalities. one patient (case 1) had rieger's anomaly. some clinical features in patients with 4p- are similar to those in patients with chromosome deletion 5p-, cri-du-chat syndrome, although 4p- individuals do not have the distinctive cry. the ocular features which distinguish ...1978104624
interference of iodine-125 ligands in radioimmunoassay: evidence implicating thyroxine-binding globulin.although there is abundant published evidence that radioiodinated antigens interfere in digoxin radioimmunoassays, other radioimmunoassays are similarly affected. we investigated the relationship of radioiodinated antigen structure to its function in the immunoassay. carrier-free 125i-labeled iodotyrosine and iodohistamine derivatives were incubated with human serum, and the bound and free fractions were separated. we demonstrated that diiodotyrosyl analogs bind avidly to serum proteins. because ...1979108034
a novel method in enzyme immunoassay: maleimide derivative of hapten for enzyme coupling.meta-maleimidobenzoyl derivative of l-thyroxine methyl ester (mbtm) was synthesized and coupled to beta-galactosidase at molar ratio of over 5 to 1. more than 97% of the enzyme was found to be labeled with mbtm. a thyroxine enzyme immunoassay was carried out with sensitivity in 0-10 microgram/100 ml range.1979108135
rat liver cytosolic azoreductase. purification and azoreductase has been purified to apparent homogeneity from the hepatic 105,000 x g supernatant fraction of 3-methylcholanthrene-treated rats. in the presence of sodium dodecyl sulfate, the purified enzyme preparation electrophoreses on polyacrylamide gels as a single protein band with a molecular weight of 30,000. in the absence of detergent, chromatography of the azoreductase on sephadex g-100 gives a molecular weight of about 52,000 suggesting that the native enzyme may exist as a dimer. t ...1979108265
3'-terminal nucleotide sequence of alfalfa mosaic virus rna 4.the sequence of the 3'-terminal 91 nucleotides of alfalfa mosaic virus rna 4, the messenger for the viral coat protein, has been elucidated. a fragment containing the 3' terminus of the rna was obtained by mild digestion with rnase t1. the primary structure of the fragment was deduced by labeling it in vitro at its 5' terminus and application of rna sequencing techniques. the sequence is completely extracistronic and is believed to contain the binding sites for the viral coat protein and replica ...1979108677
trna gene clusters in escherichia coli dna. 1975127650
[immunocytological study of the gonadotrophic and thyrotrophic cells of the rat adenohypophysis].on paraffin or semi-thin sections various anti-lh or anti-tsh sera stain indifferently all the thyrotrophs and the gonadotrophs. inversely anti-beta-tsh, anti-beta-lh or anti-beta-fsh purified sera permit the discrimination of these two cell populations. the constancy of fixation of the anti-beta-lh and anti-beta-fsh sera on all the gonadotrophs gives evidence of their ability to produce both fsh and lh. however in a few female rats the central gonadotrophs are stained more weakly by anti-beta-f ...1977145301
[intravenous cholangiography in hyperbilirubinaemia (author's transl)].the effect of bilirubin on biliary and renal excretion of methylglucamine-iodipamide at an infusion rate of 1.3, 2.6 and 5.2 mu mol/min/kg was studied by intravenous injection into five dogs with normal liver functions and chronic duodenal fistulas. unconjugated bilirubin administered in a dose of 0.1 mu mol/min/kg reduced biliary iodipamide excretion and concentration significantly, but did not affect renal contrast material excretion. this indicates that the unsatisficatory radiological result ...1979153309
effects of sodium pentobarbital on rat heart sarcolemma.the effects of sodium pentobarbital on atpase, ca2+ binding and adenylate cyclase activities of the rat heart sarcolemmal preparations were investigated. the na+ - k+ atpase activity was diminished by pentobarbital in concentrations as low as 0.3 mm. mg2+ atpase, ca2+ atpase and adenylate cyclase activities were also depressed but required 10 to 15 mm of this agent. pentobarbital in concentrations of 10 mm, however, caused an increase in sarcolemmal ca2+ binding. mitochondrial and microsomal atp ...1979155280
malignant transformation-linked imbalance: decreased xanthine oxidase activity in hepatomas.xanthine oxidase was decreased 2- to 10-fold in all examined rat hepatomas irrespective of the malignancy; growth rate and degrees of histological differentiation of the neoplasms. the affinity to substrate (km=6-8 mum) and the ph optimum (8.0) of the liver and hepatoma enzymes were the same. the reprogramming of gene expression, as manifested in the decreased activity of this key purine metabolizing enzyme, appears to be specific to neoplastic transformation. since glutamine prpp amidotransfera ...1975179860
microassay of cylic nucleotides in vessel wall. i. cyclic amp. 1976186301
tick-borne diseases of domestic animals in northern nigeria. ii. research summary, 1966 to 1976.during the first 10 years of its existence, the department of parasitology and entomology of the faculty of veterinary medicine, ahmadu bello university in zaria, nigeria, confirmed or described for the first time the occurrence of 25 different tick-borne parasites of domestic animals in the northern part of the country. most of these organisms occur as inapparent infections but may serve as complicating factors in any adverse host condition. the transmission of babesia bigemina by boophilus dec ...1977339447
quantitative estimation of leishmanial antibody titers by enzyme-linked immunosorbent assay.the response to immunization against leishmania braziliensis in rabbits was followed by measurement of antibody by enzyme-linked immunosorbent assay (elisa), passive hemagglutination, complement fixation, and countercurrent immunoelectrophoresis. passive hemagglutination and complement-fixation titers were interpreted according to standard methods, whereas elisa exact titers were derived by the equation y = a-b log x, which describes the straight line that results when absorbances are plotted ag ...1979387886
field experience with heartwater (cowdria ruminantium) in cattle.observations are reported on 2743 animals immunised against heartwater since 1958. the methods of immunisation and control of reactions are discussed. this procedure is not without risk and 0,83% of the animals died in spite of treatment. bos indicus breeds appear to have a greater resistance to heartwater and are relatively easy to immunise. of the box taurus breeds the south devon, the jersey and the charolais seem to be particularly susceptible. older animals and pregnant cows are considered ...1979553971
investigations on the natural and acquired resistance of cattle to artificial infection with cowdria ruminantium.sixty cattle, artificially immunized against c. ruminantium, were challenged 3, 6, 12 and 24 months later. levels of conglutinin were determined in pre-immunization serum samples. there appeared to be a relationship between the pre-infection levels of conglutinin and the susceptibility of the animals to heartwater: at the time of immunization 31 out of 60 cattle (51,6%) with levels in the low-titre range (1:100-1:160) showed a typical febrile response, whereas 29 (48,4%) with conglutinin levels ...1979553974
the persistence of cowdria ruminantium in the blood of recovered animals. 1978705896
the infectivity of a strain of rickettsia ruminantium maintained in--70 degrees c deep freezer and white mice. 1978749963
attempted artificaial infection or impala, blue wildebeest, buffalo, kudu, giraffe and warthog with heartwater.intravenous injection of cowdria ruminantium infected blood produced no sings of disease in four impala, aepyceros melampus; three blue wildebeest, connochaetes taurinus; a buffalo, syncerus caffer; a kudu, tragelaphus strepsiceros; a giraffe. giraffa camelopardalis and a warthog, phacochoerus aethiopicus. a control sheep injected with the same blood reacted severely and showed typical lesions of heartwater at autopsy.1976994140
[increase in the immune response in old mice with immunologic insufficiency]. 19751081214
comparative morphology of genital cones of genus ancylostoma dubini, 1843.male worms of ancylostoma braziliense, a. ceylanicum, a. kusimaense, a. malayanum, a. duodenale, a. caninum, a. tubaeforme, agriostomum vryburgi and cyclodontostomum purvisi have the external appendages beside the anogenital aperture. these anogenital structures are morphologically similar and are assumed to be homologous among the species with three pairs of teeth or more. in hookworms with two pairs of teeth, the anogenital structures are complex. anogenital features can be used as a taxonomic ...19751166351
teratogenic potential of noise in mice and rats. 19761273844
flow cytometric analysis of t cell response in mice infected with cowdria ruminantium.a 3-fold increase in the numbers of lyt-2+ t cells in the circulating blood of mice infected and re-infected with the welgevonden stock of cowdria ruminantium, as determined by flow cytometry, is supportive evidence that immunity in heartwater is cell-mediated. the rise in lyt-2+ cells only after re-infection of the mice is further evidence that the development of immunity in heartwater is dependent on the unhindered and adequate replication of c. ruminantium.19921297963
[asymptomatic carrier state in creole goats and cattle after recovery from cowdria infection in guadeloupe].creole goats and cattle in guadeloupe can be carriers of cowdriosis (heartwater: cowdria ruminantium) after recovery for a period as long as 11 months in goats and 2 months in cattle. the carrier status was demonstrated by feeding amblyomma variegatum nymphs on recovered animals and the resulting adult ticks on susceptible goats. cowdria ruminantium was not detected permanently during the carrier status.19921301623
development and persistence of cowdria ruminantium specific antibodies following experimental infection of cattle, as detected by the indirect fluorescent antibody test.different breeds of cattle were experimentally infected with palm river, a zimbabwean isolate, or ball-3, a south african isolate of cowdria ruminantium, derived from tissue culture or tick or blood stabilates. c. ruminantium specific antibody responses were detected by an indirect fluorescent antibody test (ifat) using c. ruminantium-infected bovine aortic endothelial (bae) cell cultures as antigen. the first detection of antibodies to c. ruminantium generally coincided with the peak of the feb ...19921441219
characterization of disulfide-linked heterodimers containing apolipoprotein d in human plasma lipoproteins.human plasma apolipoprotein (apo) d is a glycoprotein with an apparent molecular weight of 29,000 m(r). it is present, mainly, in high density lipoproteins (hdl) and very high density lipoproteins (vhdl). western blot analysis of hdl and vhdl using rabbit antibodies to human apod revealed major immunoreactive bands at 29,000 and 38,000 m(r), with minor bands ranging from 50,000 to and 80,000 m(r). only the 29,000 m(r) band corresponding to apod remained when the electrophoresis was conducted und ...19921479288
a cloned dna probe for cowdria ruminantium hybridizes with eight heartwater strains and detects infected sheep.the dna probe pcs20, which was cloned from the dna of the crystal springs heartwater strain from zimbabwe, cross-reacted with dnas of heartwater strains from all endemic areas, including four heartwater strains from zimbabwe, two strains from south africa, one strain from nigeria, and the gardel strain from the caribbean island of guadeloupe. by nucleic acid hybridization, the pcs20 dna probe detected cowdria ruminantium dna in all dna preparations made from plasma samples from infected sheep be ...19921572987
distribution of heartwater in the caribbean determined on the basis of detection of antibodies to the conserved 32-kilodalton protein of cowdria ruminantium.a competitive enzyme-linked immunosorbent assay (celisa) was developed to detect immunoglobulin g antibodies to the major 32-kda protein of cowdria ruminantium. a total of 1,804 serum samples collected from cattle on 19 islands in the eastern caribbean basin were tested by this celisa. a total of 133 serum samples from 10 islands (antigua, dominica, grenada, guadeloupe, martinique, montserrat, st. kitts, st. lucia, st. martin, and st. vincent) were found to be positive. the presence of antibodie ...19921629346
a technique for investigating the antigenicity of cultured rheumatoid synovial cells.antisera to rheumatoid and nonrheumatoid synovial cells were prepared by: intraarticular injection of rabbits with these cells, subsequent synovectomy, and autologous immunization of each animal with the cultured rabbit synovial cells, or homogenized whole rabbit synovial membrane. resultant antisera were studied by immunofluorescence and 51chromium cytotoxicity tests against other cultured rheumatoid and nonrheumatoid cells. activity of positive sera could be removed by absorption with nonrheum ...197988519
studies on mononuclear phagocyte progenitor cells: morphology of cells and colonies in liquid culture of mouse bone marrow. 197988518
[mechanisms of the potentiating and blocking effects of the sera from tumor patients in the leukocyte migration inhibition reaction model].in the model of the reaction of human blood leucocyte migration inhibition the in vitro study was conducted on some mechanisms of blocking and enhancement effects of the serum in 54 tumor patients. both effects were shown to be specific to an antigen. the enhancement effect could render a nonspecific action on intact cells in the presence of the corresponding antigen. this effect is thermolabile and may occur due to the interaction with cells. the blocking effect is thermostabile and may be real ...197985367
development of an in vitro microtest to assess drug susceptibility of babesia bovis and babesia bigemina.continuous cultivation of the bovine hemoparasites babesia bovis and babesia bigemina was developed as an in vitro microtest to assess parasite susceptibility to babesicidal compounds. reproducibility of parasite multiplication rates was independent of culture size, making it possible to use a microscale of 100 microliters for each test sample. inhibitory concentrations (ic50s) of a commonly used babesicide, quinuronium sulfate, evaluated by this in vitro method were found to be 5 x 10(-8) g/ml ...19911779305
clinico-pathological study of heartwater in goats.the clinico-pathological features of heartwater were studied in goats experimentally infected with a nigerian isolate of cowdria ruminantium. significant drop in haemoglobin values and marked leukopaenia caused by lymphopaenia and neutropaenia and a fall in total serum protein were observed during the course of the disease. a significant increase in the alpha-globulins and an apparent fall in the gamma-globulins also occurred. marked depletion of lymphocytes in the follicles of spleen and lymph ...197877071
candida albicans-specific ly-2+ lymphocytes with cytolytic determine whether antigen (ag)-specific cytotoxic t lymphocytes are generated during experimental candida albicans infection, purified l3t4+ and ly-2+ lymphocytes from immunized mice were cultured in the presence of syngeneic accessory cells, c. albicans ag, and interleukin 2. yeast-infected bone marrow macrophages were used as target cells in a standard 51cr-release assay. freshly isolated l3t4+ and ly-2+ lymphocytes failed to lyse either target cell type. however, ag-specific, major histoco ...19911828430
candida albicans-specific ly-2+ lymphocytes with cytolytic determine whether antigen (ag)-specific cytotoxic t lymphocytes are generated during experimental candida albicans infection, purified l3t4+ and ly-2+ lymphocytes from immunized mice were cultured in the presence of syngeneic accessory cells, c. albicans ag, and interleukin 2. yeast-infected bone marrow macrophages were used as target cells in a standard 51cr-release assay. freshly isolated l3t4+ and ly-2+ lymphocytes failed to lyse either target cell type. however, ag-specific, major histoco ...19911828430
lack of cross-protection between cowdria ruminantium and ehrlichia phagocytophila.antigenically distinct stocks of cowdria ruminatium from senegal and south africa were compared with a dutch isolate of ehrlichia phagocytophila in cross-immunity trials in goats. there was a complete absence of cross-immunity between e. phagocytophila and c. ruminantium, despite previous observations that both rickettsial organisms have certain antigenic determinants in common.19911843823
a slowly dissociating form of the cell surface cyclic adenosine 3':5'-monophosphate receptor of dictyostelium discoideum.experiments using a phosphodiesterase-minus mutant of dictyostelium discoideum indicate that ligand-induced loss of cell surface cyclic adenosine 3':5'-monophosphate binding sites (down regulation) can be evoked with concentrations of cyclic adenosine 3':5'-monophosphate as low as 10(-8) m. the loss of receptor sites is observed after 5 min of cell preincubation with cyclic adenosine 3':5'-monophosphate and can be as extensive as 75 to 80%. this decrease in binding sites is correlated with the a ...1979227901
competitive enzyme-linked immunosorbent assay for heartwater using monoclonal antibodies to a cowdria ruminantium-specific 32-kilodalton protein.hybridomas producing monoclonal antibodies (mab) to cowdria ruminantium were raised. four mabs of the igg isotype reacted in western blots with a 32-kilodalton cowdria protein (cr32), which had previously been shown to be conserved and immunodominant. a fifth mab of the igm isotype recognized a 40-kda cowdria protein. the latter mab was negative in an indirect fluorescent antibody test (ifa), whereas the other four were positive. mab no. 4f10b4 showed the strongest signal in western blots using ...19911871954
use of a most probable number method modified with a deoxyribonucleic probe to monitor control by food preservatives of natural salmonella contamination in animal meat meals.a most probable number (mpn) technique using a dna probe was developed for determination of salmonella in naturally contaminated meat meals. the method eliminated the need for 180 selective plates and 75 selective tubes and saved 27 h when compared with a traditional technique; yet it still yielded identical mpn of salmonella per 100 g in five naturally contaminated samples. the method was used to monitor the effect of a commercial food preservative (sal curb) at 0, .25, .50, 1.0, and 2.0% in me ...19911876558
antigenic diversity of cowdria ruminantium isolates determined by cross-immunity.antigenic diversity in five stocks of the tick-borne rickettsia cowdria ruminantium, the causal agent of heartwater disease of ruminants, was studied by cross-immunity trials in goats and sheep. complete absence of cross-protection was found only between the kümm and kwanyanga stocks, and in all other combinations there were various degrees of cross-immunity. immunological strain differences were more pronounced in goats than in sheep.19911896626
t cell-mediated immunity to cowdria ruminantium in mice: the protective role of lyt-2+ t cells.the inability of athymic nude mice to make a drug-aided recovery from infection with either the kümm or the welgevonden stocks of cowdria ruminantium and their inability to mount an immune response, suggest that immunity in heartwater is cell-mediated. the adoptive transfer of immunity with the spleen cells of mice immune to the welgevonden stock is supportive evidence. immune spleen cells depleted of lyt-2+ t cells are unable to confer resistance to challenge to recipient mice, whereas the depl ...19911923379
ultrastructural morphology of cowdria ruminantium in midgut epithelial cells of adult amblyomma hebraeum female ticks.amblyomma hebraeum male and female ticks, experimentally infected as larvae with the ball 3 stock of cowdria ruminantium, were fed on a heartwater susceptible sheep. the initial attachment of the males was required as a pre-requisite for female attachment. reticulate bodies were the predominant morphologic form of cowdria observed in gut epithelial cells after 1-3 days of feeding. single intermediate bodies and no elementary bodies were observed. organisms were found within a membrane-bound vacu ...19911923381
protective immunity to heartwater (cowdria ruminantium infection) is acquired after vaccination with in vitro-attenuated rickettsiae.a senegalese (s) stock of cowdria ruminantium was passaged on bovine umbilical endothelial cells with an average interval of 13.9 days (range, 8 to 34 days) between passages. the virulence of infected bovine umbilical endothelial cultures was tested in susceptible goats and sheep by intravenous inoculation of culture supernatant from passages 2 (51 days in vitro), 3 (69 days), 11 (229 days), 14 (264 days), and 16 (291 days). both animals inoculated with passages 2 and 3 died of heartwater. howev ...19911987089
in vitro isolation of cowdria ruminantium from plasma of infected ruminants.a new and simple technique for isolation of c. ruminantium in bovine and ovine vascular endothelial cells (aorta, pulmonary artery) is described. unlike previous studies, no efforts were made to retard cell growth by irradiation or chemicals. instead, heparin-derived plasma samples obtained from only those animals exhibiting prolonged or extremely high temperatures were used. in this way, c. ruminantium was isolated from 27 of 37 samples (73%) and from 22 of 26 animals (85%). a total of six zimb ...19912024445
phylogenetic position of cowdria ruminantium (rickettsiales) determined by analysis of amplified 16s ribosomal dna sequences.the 16s ribosomal dna sequence of cowdria ruminantium, the causative agent of heartwater disease in ruminants, was determined. an analysis of this sequence showed that c. ruminantium forms a tight phylogenetic cluster with the canine pathogen ehrlichia canis and the human pathogen ehrlichia chaffeensis. although a close relationship between the genus cowdria and several members of the tribe ehrlichieae has been suspected previously, the tight phylogenetic cluster with e. canis and e. chaffeensis ...19921380292
improved culture conditions for cowdria ruminantium (rickettsiales), the agent of heartwater disease of domestic ruminants.the causal agent of heartwater disease of domestic ruminants, cowdria ruminantium, can, with difficulty, be isolated and passaged in lines of bovine endothelial cells grown in the presence of the glasgow modification of eagle's minimal essential medium. however, when leibovitz's l-15 medium supplemented with 0.45% glucose at ph 6.0-6.5 is used as maintenance medium for these cells, isolation and serial passage may routinely be achieved.19901366994
relationship of the first step in protein synthesis to ppgpp: formation of a(5')ppp(5') the presence of purified escherichia coli lysyl-trna synthetase [l-lysine:trnalys ligase (amp-forming) ec], l-lysine, and atp, addition of the nucleotide ppgpp results in formation of a unique product-a(5')ppp(5') gpp. the same compound is also formed very rapidly in a cell-free protein-synthesizing system when ppgpp is added. the possible significance of this reaction in the rapid turnover of ppgpp and as a more general mechanism by which an amp residue is activated and introduced on ...1975170611
[prevention of cowdriosis and cases of sheep diseases in the niayes region of senegal].sheep originating from an heartwater-free area were immunized by the infection and treatment method, using long-acting oxytetracycline. the animals were then exposed, together with control sheep to natural infection in an enzootic area. tick counts were made to monitor the infestation and establish a correlation between infestation by certain tick species, in particular amblyomma variegatum, and the occurrence of cowdriosis. in some cases of death associated with ehrlichiosis and anaplasmosis in ...19902218032
electron microscopic study of bacillus subtilis protoplast fusion.when protoplasts derived from sporulating cells of bacillus subtilis were fused by exposure to polyethylene glycol (peg) and fixed immediately thereafter, protoplasts with two enclosed prespores could be seen by electron microscope. the number of fusion events was greatly increased, and multiply fused protoplasts appeared, when the peg-treated suspension was diluted in hypertonic broth and reincubated before fixation. this post-peg incubation effect is taken to indicate a fusion mechanism of two ...1979108247
concurrent babesiosis and ehrlichiosis in the dog: blood smear examination supplemented by the indirect fluorescent antibody test, using cowdria ruminantium as antigen.giemsa-stained, peripheral blood smears of 67 dogs, showing clinical signs typical of babesiosis or reminiscent of concurrent babesiosis and ehrlichiosis, were examined for the presence of babesia canis and ehrlichia canis. since cowdria ruminantium cross-reacts with ehrlichia, the sera of these dogs were also subjected to the indirect fluorescent antibody (ifa) test in which c. ruminantium was used as antigen. fifty-five per cent of these dogs had mixed infections of b. canis and e. canis, as j ...19902234860
an attempt to improve the immunization of sheep against heart-water by using different combinations of 3 stocks of cowdria ruminantium.neither sheep immune to the ball 3, the kwanyanga or the mara stocks of cowdria ruminantium nor those immunized with combinations of these 3 stocks were protected against challenge with the mali stock. against challenge with the welgevonden stock, however, immunization with each of the 3 combinations and with single stocks effected a protective immunity.19902234869
a differential lysis method for the isolation of cowdria ruminantium order to isolate pure cowdria ruminantium dna an enzymatic lysis procedure was used to lyse cowdria-infected bovine endothelial cell cultures differentially. infected host cells were treated with trypsin followed by dnase digestion and centrifugation. this method resulted in the isolation of intact cowdria organisms and removed bovine dna effectively.19902247935
serial prolactin and thyrotropin responses to thyrotropin-releasing hormone throughout normal human pregnancy. 1979107178
prophylaxis and prevention of viral hepatitis. 197986636
preliminary observations on the use of the capillary flocculation test for the diagnosis of heartwater (cowdria ruminantium infection).a capillary flocculation test was developed to diagnose heartwater disease of ruminants. antigen was prepared from the brains of cattle and goats highly infected with cowdria ruminantium. sera were obtained from experimentally infected ruminants which either recovered naturally or with the aid of oxytetracycline treatment. antibodies were first detected one to two weeks after clinical recovery or after treatment, and persisted for periods varying between one and four weeks. control sera collecte ...19761030824
structure and function of the cd16:zeta:gamma complex expressed on human natural-killer cells.natural-killer (nk) cells are large granular lymphocytes involved in host defense against tumor cells and virally-infected cells. in addition to natural cytotoxicity, nk cells can effect antibody-dependent cytotoxicity mediated by cd16 (fc gamma riiia alpha). it has recently been shown that cd16 is associated with disulfide-linked dimers composed of 2 homologous sub-units, zeta and gamma. these transducing molecules are also associated with other multimeric cell-surface receptors such as the t-c ...19921428397
identification of babesia bovis and cowdria ruminantium on the island of unguja, zanzibar.babesia bovis and cowdria ruminantium were identified for the first time in cattle on unguja island, zanzibar. b bovis is common and widespread, although clinical disease had not been diagnosed previously. the vector of heartwater, amblyomma variegatum, is found throughout unguja but c ruminantium appears to be more localised in distribution than b bovis.19902301128
experimental transmission of cowdria ruminantium (rickettsiales) by the american reptile tick amblyomma dissimile koch, 1844.a senegalese isolate of the rickettsia cowdria ruminantium was transmitted transstadially by nymphs of the american reptile tick amblyomma dissimile. only eight nymphs, fed as larvae on a saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat. since a. dissimile usually feeds on snakes, iguanas and lizards in central america, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. however, the ...19921395974
observations on mouse-infective stocks of cowdria ruminantium: microscopical demonstration of the kwanyanga stock in mouse tissue and the carrier-status of the senegal stock in mice.the behaviour of two different stocks of cowdria ruminantium was investigated in mice. the mouse-pathogenic kwanyanga stock of c ruminantium was microscopically demonstrated in mice in capillary endothelial cells of the lung, spleen, kidney, liver and brain. mice of the ninth passage of the senegal stock, which is infective but not pathogenic to mice, were kept alive for a year. their blood and homogenised spleens, inoculated intravenously, caused fatal heartwater in a goat. however, the senegal ...19902359890
adult amblyomma hebraeum burdens and heartwater endemic stability in cattle.several conclusions of importance to studies on the epidemiology of heartwater were drawn from an investigation in which the numbers of adult amblyomma hebraeum ticks, to which a closed herd of hereford cattle were exposed over a period of 6 1/2 years, were manipulated. with a tick cowdria ruminantium infection rate of 3-5%, an endemically stable situation was created by dipping the herd only when an average of 10 adult male and female a. hebraeum ticks were counted on 10 animals. when the avera ...19921513597
infection rates with cowdria ruminantium of nymphs and adults of the bont tick amblyomma hebraeum collected in the field in zimbabwe.cowdria ruminantium (heatwater) infection rates of field populations of the bont tick, amblyomma hebraeum, were determined at two locations in the southern lowveld of zimbabwe. at mbizi quarantine station, unfed adult males and females, and nymphs were collected at intervals over a 2-year period using traps. at lemco ranch, engorged nymphs were collected on three occasions from weaner calves and allowed to moult to adults. the unfed ticks were fed in small pools on heartwater-susceptible sheep, ...19902399648
preservation of cowdria ruminantium at low termperatures.a nigerian isolate of cowdria ruminantium was rapidly frozen with or without 10 per cent dimethyl sulphoxide at -85 degrees c and -196 degrees c. all animals inoculated with the frozen stabilates died of heartwater fever.19751215687
heartwater. the morphology of cowdria ruminantium and its staining characteristics in the vertebrate host and in vitro.the morphology of cowdria ruminantium is described and its staining characteristics in the vertebrate host and in vitro are summarized. morphologically, the organisms are characterized in the cytoplasm of endothelial cells, macrophages and reticulo-endothelial cells. based on the morphology of the internal structure of the organisms, elementary (electron-dense), intermediate and reticulate bodies are identified. each organism is surrounded by a double membrane and a "capsule" is evident around a ...19872452396
distinctive staining of colonies of cowdria ruminantium in midguts of amblyomma hebraeum.mallory's phloxine-methylene blue stain was used to differentiate colonies of cowdria ruminantium in midgut epithelial cells of nymphal amblyomma hebraeum that had been infected as larvae. gut tissues were collected from nymphs that had fed on a susceptible sheep and were fixed in formol-saline on the day of repletion. paraffin sections, 3-4 micron thick, were then stained and this rendered colonies and cell nuclei densely blue against a uniformly pink background of tick tissues. colonies were e ...19872452397
aliphatic medium chain tricarboxylic acids in rat urine.three aliphatic tricarboxylic acids have been found in rat urine. they have been identified as 6-carboxy-5-undecenedioic acid, 6-carboxy-5-dodecenedoic acid, and 6-carboxy-5-tridecenedioic acid. the carbon skeleton structure was determined by mass spectra of the hydrogenated methyl esters. the double bond position was determined after osmium tetroxide oxidation followed by trifluoroacetylation and mass spectrometry and by infrared spectrometry. the compounds were present in the urine when the ra ...1976186550
the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater).the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater) was investigated. transstadial (nymph to adult) and intrastadial transmission were demonstrated. males transferred from live or dead hosts to live hosts were shown to transmit c. ruminantium repeatedly. it was concluded that male transmission is of importance in the epidemiology of heartwater.19892588467
time course of cerebral blood flow and histological outcome after focal cerebral ischemia in rats.the relation between time-dependent changes in cerebral blood flow and the appearance of infarction after focal cerebral ischemia is still a matter for debate. the aim of this study was to measure perfusion after simultaneous occlusions of the left middle cerebral artery and ipsilateral common carotid artery in rats and correlate it with the timing and distribution of histological changes.19921636189
protection of goats against caribbean and african heartwater isolates by the ball 3 heartwater vaccine.two groups of castrated male adult goats (three goats/group) were infected intravenously with the ball 3 vaccine strain of cowdria ruminantium and treated with long-acting oxytetracycline at the onset of clinical disease 10 days later. five weeks post-vaccination one group was challenged with a caribbean isolate (gardel) and the other group with a west african isolate (mali) of c. ruminantium. non-vaccinated controls infected with either the gardel or mali isolate died. all of the vaccinated ani ...19892665252
serotypes in cowdria ruminantium and their relationship with ehrlichia phagocytophila determined by immunofluorescence.two tick-borne rickettsial pathogens of ruminants, cowdria ruminantium (causative agent of heartwater disease) and ehrlichia phagocytophila (causative agent of tick-borne fever), were successfully cultivated in caprine or ovine neutrophilic granulocytes. infected cultures were subsequently used as antigens in the indirect fluorescent antibody test. low-level bilateral serological cross-reactions could be detected between cowdria and ehrlichia. in addition, comparison of five cowdria stocks using ...19892696198
heartwater in nigeria. ii. the isolation of cowdria ruminantium from live and dead animals and the importance of routes of inoculation.a study was carried out to determine which materials from animals dying or dead of heartwater could initiate the disease in susceptible goats, using the intravenous and subcutaneous routes. c. ruminantium was consistently isolated by intravenous injection of the whole blood or of lung macrophages and by subcutaneous injection of brain homogenate. in animals dead of heartwater, it appeared that isolation of the organism was achieved only when extensive post-mortem autolysis had not supervened. ex ...1978625798
cowdria ruminantium is recognized by a monoclonal antibody directed against the major outer membrane protein of chlamydia trachomatis.the relationship between cowdria ruminantium and chlamydia trachomatis was studied by immunofluorescence. a monoclonal antibody directed against the major outer membrane protein of c. trachomatis recognized rickettsial colonies of c. ruminantium in infected goat brain. no specific fluorescence was observed in non-infected brain. two commercial chlamydia-specific monoclonal antibodies as well as polyvalent anti-chlamydia rabbit serum recognized c. trachomatis, but did not recognize cowdria. moreo ...19911712142
the tick-borne rickettsia cowdria ruminantium has a chlamydia-like developmental cycle.the development of the tick-borne rickettsial pathogen cowdria ruminantium (s stock) was studied in bovine umbilical endothelial (bue) cell cultures and in goat choroid plexus, by light- and electron microscopy. cowdria divided by binary fission within intracytoplasmic vacuoles resulting in large colonies of reticulate bodies. after three to four days in culture, reticulate bodies developed into smaller intermediate bodies characterized by an electron-dense core. shortly before disruption of the ...19911780122
lovastatin inhibits gallstone formation in the cholesterol-fed prairie dog.the efficacy of lovastatin, an inhibitor of hepatic cholesterol synthesis in the prevention of cholesterol gallstone formation, was evaluated in the prairie dog model. two groups of animals were maintained on either nonlithogenic or 1.2% cholesterol-enriched chow for 21 days. seven of the animals in each group received lovastatin, and the remaining six received only distilled water. all of the cholesterol-fed/water-treated animals had crystals and 83% had gallstones, but none of the cholesterol- ...19911867522
absence of antibody to cowdria ruminatum in sera from humans exposed to vector ticks. 19921598655
in vivo dna cross-linking by cyclophosphamide: comparison of human chronic lymphatic leukemia cells with mouse l1210 leukemia and normal bone marrow cells.alkaline elution was done on a variety of cells following cyclophosphamide (cy) treatment in vivo. cells used were l1210 leukemia, normal mouse bone marrow, and peripheral blood cells obtained from a patient with chronic lymphatic leukemia (cll). endpoints used were determination of single strand breaks, dna-dna interstrand and dna-protein cross-links. after treatment of mice with cy (4 mg/mouse), low levels of single strand breaks were observed in both l1210 leukemia and cdf1 normal bone marrow ...19892731167
the isolation of nucleic acid sequences specific for cowdria ruminantium.screening of a genomic library of cowdria ruminantium has yielded twelve clones hybridizing to cowdria dna. these clones should be suitable for development into dna probes specific for this organism.19892748132
an attempt to establish an inbred line of mice genetically resistant to cowdria attempt to establish an inbred line of mice resistant to cowdria ruminantium failed. first generation couples were constituted from those mice out of 100 males and 100 females that had survived infection with the kümm stock of c. ruminantium and that were serologically negative to the indirect fluorescent antibody test. an attempt to establish 10 separate inbred lines by constituting next generation brother and sister matings from predominantly seronegative survivor mice from the preceding ge ...19902293139
immunity of tick-exposed seronegative and seropositive small stock challenged with two stocks of cowdria ruminantium.nineteen per cent and 32% of serologically positive sheep and goats in heartwater endemic areas of the republic of south africa were susceptible to challenge with, respectively, the ball 3 and welgevonden stocks of cowdria ruminantium. there was good correlation between the results of the indirect fluorescent antibody test and immunity, since without exception all the seronegative animals reacted when they were challenged. the fact that only 74% of the seropositive sheep and goats were immune to ...19892812702
the heterogenicity of cowdria ruminantium stocks: cross-immunity and serology in sheep and pathogenicity to mice.ten stocks of cowdria ruminantium (ball 3, breed, comoro, germishuys, kümm, kwanyanga, mali, mara, nonile and welgevonden) were compared from a cross-immunity, serological and mouse pathogenicity point of view. they were found to differ in varying degrees. except for the ball 3, comoro and germishuys stocks that were similar but not identical, there was no pattern in the antigenic diversity of the 10 stocks. the welgevonden stock emerged as the stock that elicits an immunity against most of the ...19892812704
increased pathogenicity of an ehrlichia-like agent after passage through amblyomma hebraeum: a preliminary report.after being passaged through 3 generations of amblyomma hebraeum, an ehrlichia-like agent isolated from an adult hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater. cross-immunity between this agent and several stocks of cowdria ruminantium and high levels of antibody elicited by the agent against 2 stocks of c. ruminantium in the indirect fluorescent antibody test, confirmed its close relationship to cowdria.19902293132
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