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[electron microscopic studies of spontaneous and experimentally induced neoplasms and of normal skin of mastomys natalensis (gra giessen and wsa giessen strains)]. 19816794250
an arenavirus isolated from wild-caught rodents (pramys species) in the central african republic.we isolated nine arenavirus strains from blood and/or tissues of praomys sp. rodents wild-caught in derived savannah and forest gallery areas of the central african republic (car). convalescent serum from either humans or animals infected by lassa, mozambique, or lymphocytic choriomeningitis virus cross-reacted with the strains from the car. however, monoclonal antibodies to these three viruses gave a profile against the car strains suggesting major antigenic differences between each of them and ...19836862813
occurrence of microfilariae in various hollow organs and in the peritoneal cavity after treatment of litomosoides carinii infected mastomys natalensis with diethylcarbamazine and haloxon.treatment of litomosoides carinii infected mastomys natalensis with diethylcarbamazine (dec: 500 mg/kg p.o.) was followed by increased occurrence of microfilariae in the bronchi of the host after 40 min and lasting at least until 6 h after treatment. after 4 h, increased levels of larvae were observed in the gut. only a few microfilariae occurred in the bladder and sputum. accumulations of microfilariae were found furthermore in the lnn. hepaticae whereas no changes were observed in the inguinal ...19836880345
case-control study of mastomys natalensis and humans in lassa virus-infected households in sierra leone.lassa virus infection and antibodies were studied in households where lassa fever cases occurred, and compared to those in nearest neighbor houses and "far" houses located across the village from case houses. seventy-nine percent of all rodents caught in the houses were mastomys, the natural reservoir of lassa virus. rodent infection was not randomly distributed, but rather focal. thirty-nine percent of the mastomys in case houses were viremic, compared to 3.7% in control houses. human antibody ...19836881432
naturally occurring autoantibodies in aged praomys (mastomys) natalensis. 19816971720
changes in lysosomal enzymes of peritoneal exudate cells in albino rats and mastomys natalensis during plasmodium berghei infection.activities of certain lysosomal enzymes of peritoneal exudate cells were followed during plasmodium berghei infection in two experimental hosts. in albino rats, where sterile immunity against the infection develops, levels of beta-d-glucuroniodase and acid phosphatase activities were increased several times the normal values. on the other hand, in mastomys natalensis, which succumbs to infection, levels of both the enzymes decreased considerably. cathepsin d activity did not change to a signific ...19807003382
on the longevity and behaviour of microfilariae of wuchereria bancrofti, brugia pahangi and dirofilaria immitis transfused to laboratory rodents.microfilariae of wuchereria bancrofti and brugia pahangi, which were inoculated into meriones unguiculatus and mastomys natalensis respectively, were found in the peripheral blood of the rodents until the ninth day after infection, but no microfilarial periodicity was observed. microfilariae of w. bancrofti disappeared much faster from the peripheral blood of jirds after reinfection than after the first inoculation. microfilariae of dirofilaria immitis inoculated into m. natalensis and laborator ...19807003830
scanning electron microscope study on larvae of wuchereria bancrofti from the vector and from experimental rodent hosts.the surface structures of larvae of wuchereria bancrofti from liberia were examined by scanning electron microscopy. for this study microfilariae from man, first-stage, second-stage, and third-stage larvae from the vector aedes aegypti, and fourth-stage larvae from the experimental rodent hosts mastomys natalensis and meriones unguiculatus were available. from these larvae the structure of the anterior ends, the cuticle in the midbody regions, and the posterior ends are presented. as an obvious ...19807003854
a summary of the efficacy of praziquantel against schistosomes in animal experiments and notes on its mode of action.2-cyclohexylcarbonyl-1,2,3,6,7,11b-hexahydro-4h-pyrazino[2,1-a]isoquinolin-4-one (praziquantel, embay 8440, biltricide) is broadly effective in mice, syrian hamsters and mastomys natalensis experimentally infected with schistosoma mansoni, s. haematobium, s. japonicum, s. intercalatum, and s. mattheei. in vitro it is equally effective against all developmental stages of s. mansoni whilst in vivo it is especially effective against young schistosomules and mature worms. 14c-praziquantel is rapidly ...19817016122
synthesis of some novel amodiaquine analogues as potential antimalarial and antifilarial compounds.ten amodiaquine analogues, which are hybridized molecules of amodiaquine and diethylcarbamazine, were designed and synthesized. six analogues, all bearing a basic tertiary amino function at their side chain, were active against plasmodium berghei in mice and inhibited the mobility of adult worms and microfilariae of breinlia booliati in vitro. they were inactive against litomosoides carinii in mastomys natalensis. the most active antimalarial compound, 7-chloro-4-[alpha-[[n-(4-methyl-1-piperazin ...19817031248
recovery of a lassa-related arenavirus in zimbabwe.immunofluorescent antibodies to "mozambique" virus, a close relative of lassa virus, were found in 11 of 55 mastomys natalensis and 1 of 13 aethomys chrysophilus rodents captured near que que and chiredzi, zimbabwe. six strains of mozambique virus, identified by use of specific monoclonal antibodies to the agent, were recovered from visceral tissues of m. natalensis rodents. all mastomys having virus or antibodies to this agent were of the chromosomal form 2n = 32 (m. natalensis). these data ext ...19817034562
[experiments in vitro with litomosoides carinii (nematoda: filarioidea) ii. influence of different sera on the release of microfilariae and experiments on the readiness for copulation of the worms (author's transl)].when fetal calf serum or human serum is added to the culture medium tc 199, adult females of litomosoides carinii release the same amount of microfilariae in vitro as after addition of cotton rat serum. in contrast, in media with serum of meriones unguiculatus or mastomys natalensis only a few microfilariae are released; moreover, addition of mastomys serum immobilizes them. when males and females are kept together, the same amount of microfilariae is released as compared with single females. wo ...19827051596
the binding of staphylococcal protein a by the sera of different animal species.the capacity of purified immunoglobulin or serum to bind (125i)-labeled staphylococcal protein a (spa) was measured by means of an immunofiltration assay that facilitated the examination of large numbers of sera and required only a minute quantity of each. sera from 80 species, including humans, laboratory animals, domestic animals, and a variety of african mammals were examined. a wide interspecies variation in the spa-binding capacity of serum immunoglobulins was confirmed. only small variatio ...19827061862
analysis of histamine receptors in the central thermoregulatory mechanism of mastomys natalensis.1 the effect of intracerebroventricular (i.c.v.) injection of histamine on the rectal temperature of mastomys natalensis at ambient temperatures of 10, 24 and 33 degrees c has been studied. 2 low doses (0.1-1.0 microgram) of histamine produced hypothermia while larger doses (5-20 micrograms) produced dose-dependent hyperthermia. the hypothermic effect was significantly antagonized by mepyramine while the hyperthermia was blocked by cimetidine. 3 histamine h1-receptor agonists, 2-methyl-histamine ...19827074279
scanning electron microscope study of adult brugia malayi.the fine structures of the surface of brugia malayi obtained from mastomys natalensis are demonstrated by scanning electron microscopy. the head of the parasite is bulbous in shape. the amphidial openings lie beside small elevations. the surface structure of the inner papillae is smooth with a small elevation in the middle. the outer papillae are grooved. the cuticular annulation in the midbody region of the female worm is narrower than that of the male cuticle. in the posterior region of the fe ...19827101437
a histopathological survey of aged praomys (mastomys) natalensis.this histopathological study shows that mastomys develops a wide variety of neoplastic and nonneoplastic lesions with age. in comparing neoplastic lesions of mastomys with those generally found in mice and rats, mastomys is more or less unique with respect to the development of lymphoepithelial thymomas (40%), parathyroid adenomas (11%), prostatic adenocarcinomas (5%), and gastric carcinoids (4%) and the absence of brain, lung, and mammary tumors. of the nonneoplastic lesions, prostatic (38%), t ...19827130638
spontaneous autoimmune thyroiditis in praomys (mastomys) natalensis. 19827166012
litomosoides carinii: effect of diethylcarbamazine on microfilaremias of mastomys natalensis harboring old infections, new infections, and transfused microfilariae.mastomys natalensis, matched according to age and microfilaremia, were divided into experimental and control groups. the former were given diethylcarbamazine (caricide, 500 mg/kg) per os. microfilariae counts were made at 15, 30, 60, and 120 min and at 1, 5, and 12 days. this protocol was performed on rats with: old infections (patent for 7 mo), new infections (patent for 10 days), and no infection but made microfilaremic by injection of blood or culture-derived microfilariae. in all treated gro ...19827175613
transmission of dipetalonema rugosicauda (syn. wehrdikmansia rugosicauda) (nematoda: filarioidea) to mastomys natalensis. 19807190342
gastric ulcer disease: gastric ulcer induced by mucosal anaphylaxis in ovalbumin-sensitized praomys (mastomys) natalensis. 19817193420
[immunization against capillaria hepatica: the effects of primary infections, x-irradiated stages, non-embryonated eggs, and soluble egg extracts (author's transl)].the influence of primary infections with embryonated infective eggs or with x-irradiated infective eggs, and of non-embryonated eggs, and egg homogenate extracts on challenge infections with capillaria hepatica was investigated. the worm reproductivity was significantly suppressed in a sublethal challenge infection given 11 days after a primary infection of mastomys natalensis with 50, 150, 400, and 800 eggs per animal. the administration of 600 x-irradiated (2.2 krd) embryonated eggs 36 days be ...19807194546
experimental prostatitis in female mastomys natalensis--a preliminary report.female mastomys natalensis were inoculated with a suspension of klebsiella pneumoniae into the bladder. all animals developed prostatitis without urinary tract infection between the 9th and the 12th day after inoculation. 10(4) - 10(5) cfu of k. pneumoniae per gram prostatic tissue could be cultivated. histologically acute purulent prostatitis was detected in most cases 6 days after infection. in the follow-up periacinar infiltration predominated.19817197068
carcinoids and adenocarcinoma of the glandular stomach in praomys (mastomys) natalensis treated with 3-methylcholanthrene.carcinoids and adenocarcinoma of the glandular stomach, analogous to those in man, were found in the chemically treated and control groups of praomys (mastomys) natalensis. the tumors were similar to the ones occurring spontaneously in this unique species. adenocarcinoma of the pyloric and antral regions developed irrespective of treatment but of the fundic region only in the chemically treated group.19807202913
the submaxillary salivary glands of the african rodent praomys (mastomys) natalensis as the richest available source of the nerve growth factor. 19817238613
a technique for chronic cannulation of the lateral cerebral ventricle in mastomys natalensis. 19817239572
[x-ray sensitivity of embryonated capillaria hepatica eggs and serum-gldh activities and antibody titres in mastomys natalensis infected with untreated or irradiated eggs]. 19817245841
absence of anti-acetylcholine receptor antibodies in praomys (mastomys) natalensis.it has been suggested in the past that praomys (mastomys) natalensis might be an animal model for human myasthenia gravis. this suggestion was based on the occurrence of thymomas and autoantibody to striated muscle in this animal species. myasthenia gravis in man is associated with anti-striated muscle antibody and thymoma as well as antiacetylcholine receptor antibody. this prompted us to search for such autoantibodies in mastomys. there was no evidence of anti-acetylcholine receptor antibody i ...19817249398
susceptibility of members of the mastomys natalensis species complex to experimental infection with yersinia pestis. 19817264374
observations on the food habits of some african rodents.food habits of four common species of african rodents: the giant rat (cricetomys gambianus), the black house rat (rattus rattus), the multimammate rat (mastomys natalensis) and the pygmy mouse (mus minutoides) were studied on the basis of stomach content analysis, habitat sampling and experimental trials with caged animals. vegetable items (especially grass, grains and tubers) formed the bulk of the food of all the species. oil-palm nuts and kernels were also common in the guts of c. gambianus a ...19807323341
morphology of experimentally induced so-called keratoacanthomas and squamous cell carcinomas in 2 inbred-lines of mastomys natalensis. 19817343569
effect on host metabolism of litomosoides carinii infection in mastomys natalensis. 19817348724
[neoplasms of the skin in a wild-colored inbred strain of mastomys natalensis (wsa giessen)]. 19807404971
[capillaria hepatica infection of mastomys natalensis: dependence of granuloma formation in intravenously injected eggs on the stage of infection]. 19807415663
schistosoma mansoni: host antigen occurrence on worms recovered from laboratory vertebrate animals.by transferring schistosoma mansoni (12 to 14-day-old worms) from one host into the peritoneal cavity of a host of a different species, it was possible to demonstrate that worms grown in rats, hamsters, mastomys natalensis and cebus monkeys were rejected by recipient animals previously immunized against red blood cells of the donor hosts. these results suggest that host-like antigens are acquired by s. mansoni in all hosts. the transfer of worms into the peritoneal cavity has proved to be a simp ...19807443298
mastomys (=praomys) natalensis is not a rattus (mammalia: rodentia): karyological evidence.certain past studies have suggested that the taxa mastomys (= praomys) and rattus were closely allied phyletically. we here present detailed (c- and g-banding and nor's) comparisons of the karyotypes of m. natalensis (2n = 36) and r. norvegicus (2n = 42). a standardized g-banded karyotype of m. natalensis is also presented. about 45% of the g-banded karyotype of m. natalensis is homologous with that of r, norvegicus. autosomal constitutive heterochromatin is nearly equivalent in the two species; ...19807449441
praomys (mastomys) natalensis: animal model for study of histamine-induced duodenal ulcers.praomys (mastomys) natalensis, an african rodent ranging in size between a mouse and a rat, is more susceptible to the induction of duodenal ulcers by constant infusion of exogenous histamine through an osmotic minipump implanted subcutaneously than other rodent species tested such as mouse, rat, or guinea-pig. by increasing the doses of infused histamine, there were increases in the incidence, intensity, and perforation rate of duodenal ulcers in mastomys. the induction of duodenal ulcers in ma ...19817450402
[capillaria hepatica infection of mastomys natalensis: pathological changes in liver and spleen following infections with embryonated and x-ray attenuated eggs]. 19807467992
immunoprophylactic potential of a 120 kda brugia malayi adult antigen fraction, bma-2, in lymphatic filariasis.a 120 kda antigen containing sds-page fraction bma-2 isolated from brugia malayi adult parasite was highly reactive with normal sera from filarial endemic area. bma-2 was analysed for its prophylactic potential in in vitro and in vivo. sera collected from bma-2 immunized jirds induced a significant level (80 to 90%) of protection against infective larvae and microfilariae in in vitro adcc assay as well as in in situ micropore chamber implantation studies. mastomys natalensis immunized with bma-2 ...19957494640
copresence of prostaglandin ep2 and ep3 receptors on gastric enterochromaffin-like cell carcinoid in african rodents.prostaglandins (pgs) have important roles in the regulation of gastric acid secretion. the aim of this study was to examine the possible presence of pg receptors on the gastric enterochromaffin-like (ecl) carcinoid of mastomys natalensis, which might be a useful model of normal ecl cells.19957542217
polyamine uptake by a rodent filariid, acanthocheilonema viteae (nematoda: filarioidea).helminth parasites lack the capacity to synthesize polyamines de novo. with the view to characterise alternative pools for the replenishment of polyamines, uptake of spermidine and spermine, were studied in acanthocheilonema viteae, a parasite known to infect rodents. motile worms recovered from the subcutaneous tissues of experimentally infected mastomys natalensis were incubated in vitro with radiolabelled polyamines for the uptake assays. a time-dependent, temperature-sensitive, energy-requir ...19957584620
status of hepatic glutathione-s-transferase(s) during plasmodium berghei infection and chloroquine treatment in mastomys natalensis.plasmodium berghei infection in mastomys natalensis impaired the hepatic mitochondrial, microsomal and cytosolic glutathione-s-transferase(s) activity with 1-chloro-2,4-dinitrobenzene as substrate. the enzyme activity was concomitantly decreased with rise in parasitaemia. the decreased enzyme activity due to infection was almost normalized with oral treatment of 16 mg (kg body wt)-1 of chloroquine for 4 days.19957622326
the testis-determining gene, sry, exists in multiple copies in old world rodents.sry is a unique gene on the y chromosome in most mammalian species including the laboratory mouse, mus musculus, and the closely related european wild mouse species m. spicilegus, m. macedonicus, and m. spretus. in contrast, sry is present in 2-6 copies in the more distantly related asian mouse species m. caroli, m. cervicolor, and m. cookii and in 2-13 copies in the related murid species pyromys saxicola, coelomys pahari, nannomys minutoides, mastomys natalensis, and rattus norvegicus. copy num ...19947698639
role of endogenous cyclo(his-pro) in cold-induced hypothermia in the desert rat (mastomys natalensis).central administration of exogenous cyclo(his-pro) (chp) is known to produce hypothermia in rodents. in the present study, we examined the role of endogenous chp in cold-induced hypothermia in the desert rat, mastomys natalensis. the results of these studies show that a rise in hypothalamic chp content accompanied a decrease in rectal temperature during cold exposure. immunoneutralization of endogenous chp resulted in a significant decline in cold-induced hypothermia. in addition, central admini ...19947700849
analysis of genomic sequences of 95 papillomavirus types: uniting typing, phylogeny, and taxonomy.our aim was to study the phylogenetic relationships of all known papillomaviruses (pvs) and the possibility of establishing a supratype taxonomic classification based on this information. of the many detectably homologous segments present in pv genomes, a 291-bp segment of the l1 gene is notable because it is flanked by the my09 and my11 consensus primers and contains highly conserved amino acid residues which simplify sequence alignment. we determined the my09-my11 sequences of human pv type 20 ...19957707535
mastomys natalensis and tatera gambiana as probable reservoirs of human cutaneous leishmaniasis in nigeria.leishmania sp. was isolated from the livers and spleens of 4 of 56 mastomys natalensis and one of 21 tatera gambiana in keana district, nigeria; none of the rodents had cutaneous lesions. parasites were not found in 42 rattus rattus. experimentally infected mice developed cutaneous lesions characteristic of l. major infection. the organisms could not be cultivated in vitro.19957747299
are enterochromaffinlike cell tumours reversible? an experimental study on gastric carcinoids induced in mastomys by histamine2-receptor blockade.a rapid induction of enterochromaffinlike (ecl) cell tumours has been shown in praomys (mastomys) natalensis subjected to histamine2-receptor blockade. in the present study the reversibility of ecl cell proliferation induced by acid inhibition was investigated. short-term treatment (8 weeks) with the histamine2-receptor antagonist loxtidine caused a moderate hypergastrinemia, accompanied by a minor increase in histamine contents and a 2-fold increased volume density of the endocrine cells in gas ...19957770630
[the host-opportunistic protozoa system. the dissemination of leishmania infantum infection in naturally susceptible laboratory animals subjected to drug-induced immunosuppression].the possibility to awake the disseminated infection of leishmania infantum in golden hamsters mesocricetus auratus, hispid cotton rats sigmodon hispidus, soft furred rats mastomys natalensis by means of different immunodepressants has been examined. on the background of the immunosuppression caused by corticosteroids of short time activity (metipred, hydrocortison) leishmaniae were revealed both in the target organs (spleen, liver, marrow) and in lungs, in cases of using the corticosteroid of pr ...19947816511
gastric carcinoid tumors: the biology and therapy of an enigmatic and controversial lesion.gastric carcinoid tumors were previously believed to be rare lesions, representing less than 2% of all carcinoid tumors and less than 1% of all stomach neoplasms. more recent studies have demonstrated that they may constitute as much as 10-30% of carcinoid tumors. patients with conditions associated with hypergastrinemia, such as chronic atrophic gastritis, zollinger-ellison syndrome with multiple endocrine neoplasia type 1 (zes-men-1), and pernicious anemia, display a markedly elevated incidenc ...19957872269
expression of cck-a and cck-b/gastrin receptors in enterochromaffin-like cell carcinoids of mastomys natalensis. 19947910444
gastrin receptor genes are expressed in gastric parietal and enterochromaffin-like cells of mastomys natalensis.although gastric enterochromaffin-like (ecl) carcinoid tumors are known to develop in patients with long-standing hypergastrinemia, the expression of the gastrin receptor gene in ecl cells has not yet been demonstrated. therefore, this study was designed to examine gastrin receptor gene expression in ecl cells. mastomys gastric mucosal cells isolated by enzyme dispersion were separated into 10 fractions (f1-10) by centrifugal elutriation. each fraction was examined histologically to determine wh ...19947924734
picroliv affects gamma-glutamyl cycle in liver and brain of mastomys natalensis infected with plasmodium berghei.picroliv, the standardized preparation of iridoid glycosides from picrorhiza kurrooa, at the dose of 6 mg/kg, po for two weeks provided significant protection against depletion of reduced glutathione levels in liver and brain of plasmodium berghei infected mastomys natalensis. the activation of gamma-glutamyl transpeptidase enzyme and decreased levels of cysteine, sulphydryl groups as well as glutathione synthesis in both tissues due to p. berghei infection were reversed by picroliv. enzymatic a ...19947927525
distribution of mrna for cck-b receptor in the brain of mastomys natalensis: abundant expression in telencephalic neurons.the distribution of cholecystokinin b (cck-b) receptors in the mastomys brain was studied using northern blot analysis and in situ hybridization technique. by northern blot analysis using 32p-labeled cdna probe, the cortex had the highest hybridization signal of cck-b receptor mrna in the brain. the olfactory bulb and hippocampus showed a moderate level of signals. in situ hybridization using 35s-labeled crna probes revealed a wide and region-specific distribution of cck-b receptor mrna in the t ...19948004467
antiparasitic activity of diallyl trisulfide (dasuansu) on human and animal pathogenic protozoa (trypanosoma sp., entamoeba histolytica and giardia lamblia) in vitro.garlic (allium sativum l.) and one of its major components, allicin, have been known to have antibacterial and antifungal activity for a long time. diallyl trisulfide is a chemically stable final transformation product of allicin which was synthesized in 1981 in china and used for treatment of bacterial, fungal and parasitic infections in man. the activity of diallyl trisulfide was investigated in several important protozoan parasites in vitro. the ic50 (concentration which inhibits metabolism o ...19948024350
brugia malayi in mastomys natalensis: influence of immunostimulators on exertion of antifilarial activity of diethylcarbamazine.the effect of immunopotentiators (freund's complete adjuvant and cdri compound no. 84/201) has been evaluated on exertion of antifilarial activity of diethylcarbamazine (dec) at different dose levels in mastomys natalensis experimentally infected with brugia malayi. dec alone exhibited dose dependent micro- as well as macrofilarial action. in combination with immunomodulators, activity of dec was significantly enhanced even at a lower dose level (12.5 mg/kg). however at higher dose level (> 25 m ...19948066377
canine oral papillomavirus genomic sequence: a unique 1.5-kb intervening sequence between the e2 and l2 open reading frames.the canine oral papillomavirus (copv) is associated with oropharyngeal papillomatosis in dogs, coyotes, and wolves. we have determined the complete nucleotide sequence of copv, the largest of all known pv genomes (8607 bp). the genomic architecture of the copv genome is similar to that of other pvs except for a unique and large noncoding region of 1.5 kb between the end of the early region (e2) and the beginning of the late region (l2) and a small (345 bp) upstream regulatory region between the ...19948091677
rapid induction of enterochromaffinlike cell tumors by histamine2-receptor blockade.the effect of acid inhibition on gastric endocrine cells was investigated in praomys (mastomys) natalensis. long-term treatment (1 to 32 weeks) with an irreversible histamine 2-receptor blocker (loxtidine) caused a sustained increase in plasma gastrin levels, which was accompanied by a gradual increase in histamine and histidine decarboxylase activity of the gastric oxyntic mucosa. the density of endocrine cells in the oxyntic mucosa increased gradually, doubled by 8 weeks, and was three times t ...19938097370
gastrin/cck-b receptors on brain, gastric parietal cells and ecl carcinoid tumor of mastomys natalensis.cholecystokinin (cck)-8 and human gastrin i (gastrin) were found to be almost equipotent in displacing the specific binding of not only 125i-cck-8 but also 125i-gastrin to both ecl carcinoid tumor and parietal cell membranes of mastomys natalensis. these binding specificities of the native gastrin receptors for cck-8 and gastrin were identical to that of the cloned gastrin receptor from the ecl carcinoid tumor expressed on cho-k1 cells. in contrast, cck-8 was approximately 10-20 times as potent ...19938182917
the mastomys natalensis papillomavirus: nucleotide sequence, genome organization, and phylogenetic relationship of a rodent papillomavirus involved in tumorigenesis of cutaneous epithelia.mastomys natalensis is a rodent of african origin afflicted with a very high incidence of skin tumors (keratoacanthomas and squamous carcinomas), which are associated with a papillomavirus, m. natalensis papillomavirus (mnpv). we have determined the genomic sequence of mnpv, which has a size of 7687 bp. the genomic organization is similar to that of other papillomaviruses, with open reading frames e6, e7, e1, e2, and e4 in the early and l2 and l1 in the late region. due to an unusually large hin ...19948291235
immunoreactive proteins of acanthocheilonema viteae (nematoda: filarioidea) adults: solubilization in various detergents.for optimal solubilization of immunoreactive proteins of filarial parasites, adult worms of acanthocheilonema viteae were extracted in different detergents including anionic, cationic, nonionic and zwitterionic agents under varying incubation periods. each preparation was then analysed by sds-page and immunoblotting using pooled sera from mastomys natalensis infected with a. viteae. amongst the detergents used, maximum immunoreactive proteins were exposed by sodium dodecylsulphate (sds), closely ...19938314178
characterization of gastrin/cck receptors on gastric carcinoid tumor membrane of mastomys natalensis.recently, we identified the specific binding site for gastrin on the gastric carcinoid tumor of mastomys (praomys) natalensis. in this study, precise characterization of the gastrin binding site on these tumors was performed. both 125i-human gastrin i (gastrin) and 125i-cck-8 bound specifically to the cell membrane, and scatchard analysis revealed a high affinity binding site for each ligand with similar kd and bmax values. the specific binding of both 125i-gastrin and 125i-cck-8 was displaced i ...19938441820
ras involvement in signal transduction by the serotonin 5-ht2b receptor.the family of serotonin 5-ht2 receptors stimulates the phospholipase c second messenger pathway via the alpha subunit of the gq gtp-binding protein. here, we show that agonist stimulation of the 5-ht2b receptor subtype stably expressed in the mouse fibroblast lmtk- cell line causes a rapid and transient activation of the proto-oncogene product p21ras as measured by an increase in gtp-bound ras in response to serotonin. furthermore, 5-ht2b receptor stimulation activates p42mapk/p44mapk (erk2/erk1 ...19968621713
animal reservoirs of leishmaniasis in marigat, baringo district, kenya.a total of 1128 rodents belonging to seven genera were examined for leishmanial parasites over a period of sixteen months. parasites were isolated from 36 (12.5%) tatera robusta, 3 (0.5%) arvicanthis niloticus, and 2 (0.8%) mastomys natalensis. all isolates were characterised by isoenzyme analysis using nine enzymes. the enzymes examined were: malate dehydrogenase (mdh), phosphoglucomutase (pgm), glucose phosphate isomerase (gpi), isocitrate dehydrogenase (icd), nucleoside hydrolase (nh), glucos ...19968625862
the effect(s) of carbaryl-treated seed on body maintenance and survival of the multi-mammate mouse, mastomys natalensis (sensu lato).maintenance, expressed as change in daily body mass, and survival rates of mastomys natalensis (sensu lato) were recorded from may to september 1994 in laboratory feeding trials, to investigate the short-term effects of a carbaryl insecticide on these variables. individuals were subjected to seeds treated with carbaryl insecticide in three different treatments (5, 10, and 20 g of carbaryl/kg of seeds). carbaryl did not have short-term adverse effects on growth and survival of this species when t ...19958668321
comparative biochemical effects of low doses of mercury ii chloride in the f344 rat and the multimammate mouse (mastomys natalensis).the biochemical effects and comparative nephroxicity of mercury ii chloride (hgcl2) dosed at 0.75 mg/kg i.p. was investigated in the fisher 344 rat (f344) and mastomys natalensis using high resolution 1h nuclear magnetic resonance (nmr) spectroscopy of urine, histopathology and clinical chemical techniques. the effects of hgcl2 treatment were followed for up to 4 days post-dosing (p.d.). in f344 rats there was extensive proximal tubular damage and renal cortical necrosis together with elevated l ...19968689530
comparative studies on the nephrotoxicity of 2-bromoethanamine hydrobromide in the fischer 344 rat and the multimammate desert mouse (mastomys natalensis).renal papillary necrosis (rpn) was induced in fischer 344 (f344) rats (n = 4) using 2-bromoethanamine hydrobromide (bea) dosed at 150 mg/kg, and in multimammate desert mice (mastomys natalensis) at 150 and 250 mg/kg (n = 4 per group). control rats and mastomys were dosed with 0.9% saline (n = 4 per group). urine was collected at regular intervals for up to 4 days post-dosing and analysed for low mw metabolites using high resolution 1h nmr spectroscopy. the urinary activity of lactate dehydrogena ...19958773180
histidine decarboxylase expression and histamine metabolism in gastric oxyntic mucosa during hypergastrinemia and carcinoid tumor formation.histamine is an important stimulator of gastric acid secretion. in experimental animals, inhibition of acid secretion by long term histamine2 receptor blockade causes hypergastrinemia, proliferation of enterochromaffin-like (ecl) cells, and formation of histamine-producing gastric carcinoids. the aim of this study was to examine the role of gastrin in histamine synthesis and metabolism of the oxyntic mucosa of normal, hyperplastic, and carcinoid-bearing mastomys natalensis. administration of exo ...19968828505
the effect of vagotomy on enterochromaffin-like cells in mastomys natalensis.the effect of vagotomy on the development of ecl cell tumours was analyzed during drug-induced hypergastrinemia in mastomys natalensis, a rodent prone to develop ecl cell tumours. untreated animals were compared with animals receiving the histamine2-receptor blocker loxtidine (lox) and with animals subjected to unilateral subdiaphragmatic vagotomy prior to loxtidine treatment (vag+lox). loxtidine (2g/l) was administered in drinking water for 48 weeks to allow multiple ecl cell carcinoids to deve ...19968832519
a report on the demonstration of microfilariae of brugia malayi in the brain of an experimental animal host, mastomys natalensis.the brain tissues of microfilaraemic animals, mastomys natalensis, which were earlier inoculated (s.c.) with brugia malayi infective larvae (100 each) were examined for the occurrence of mf. this was done by staining squash preparations of the brain tissues which were cleared off from the vascular piamater. animals with blood mf count of 50 >/per 20 cu. mm were found to harbour mf in the brain tissues. the mf count in the brain varied from 5-86/81 cu. mm (sum of mf detected in 3 tissue pieces, e ...19958847173
susceptibility of laboratory-bred rodents to the experimental infection with dengue virus type 2.various strains of laboratory-bred rodents viz. mice [swiss, c57bl/6, c3h/hej, dba/2, balb/c, nmri (nu/nu) and bl6 (nu/nu) and their heterozygous siblings (nu/+)], mastomys natalensis, wistar rat, golden hamster and indian desert gerbil were inoculated intracerebrally (ic) with mouse-adapted dengue virus type 2 (dv-2). the inoculated animals were observed daily for dullness, anorexia, occult blood in faeces, patechial haemorrhages, lacrymation, paralysis, cachexia, death. necropsied animals were ...19968891094
role of calcium influx & energy metabolism in histamine release by filarial antigen in mastomys natalensis experimentally infected with brugia malayi.the present work was undertaken to study the biochemical pathways involved in terms of role of calcium influx and status of energy metabolism in the activation of mast cells obtained from mastomys natalensis infected with brugia malayi when challenged in vitro with a potentially allergenic antigen (60 kda) of brugia malayi. it was observed that histamine release from sensitized lung and peritoneal mast cells was associated with intracellular influx of radioactive ca2+, thus establishing the role ...19968935742
effects of gastrin on the histamine-secretory and proliferative activity of cultured carcinoid cells derived from the stomach of the rodent mastomys natalensis.the effects of gastrin on the synthesis and release of histamine and on cellular proliferation were investigated in a homotransplantable carcinoid tumor implanted in the rodent mastomys natalensis and in cultured cells derived from the tumor. the homotransplanted tumor was immunopositive for histamine, synaptophysin and protein gene product 9.5, and its cells contained numerous secretory granules that were visualized by electron microscopy. when carcinoid cells were cultured in a medium with a h ...20039088027
1h nmr spectroscopic and histopathological studies on propyleneimine-induced renal papillary necrosis in the rat and the multimammate desert mouse (mastomys natalensis).the renal papillary toxin, propyleneimine (pi), was administered at 20 or 30 microliters/kg i.p. to male sprague dawley (sd) rats (n = 5), fischer 344 (f344) rats (n = 4), and to multimammate desert mice (mastomys natalensis, n = 4). urine was collected at time points up to 4 days p.d. and the toxicological response of the different animal models to pi compared using 1h nmr spectroscopy of urine, renal histopathology, and urinary assays for alkaline phosphatase (alp), lactate dehydrogenase (ldh) ...19979134698
cyclo (his-pro) modulation of body temperature at hot ambient temperature in the desert rat (mastomys natalensis).cyclo(his-pro) (chp) has been shown to facilitate cold-induced hypothermia in the desert rat mastomys natalensis. in the present study, we examined the role of endogenous chp in hyperthermia induced by hot ambient temperature (40 degrees c) in the above rodent species. the results of these studies show that housing rodents at 40 degrees c resulted in a altered distribution of chp in the brain, with a rise in hypothalamic content accompanied by an increase in rectal temperature. while administrat ...19979213362
innocuity studies of sag-2 oral rabies vaccine in various zimbabwean wild non-target species.the sag-2 modified live rabies vaccine was tested for innocuity when administered by the oral route in several potential wild non-target bait-consuming species, as follows: ten chacma baboons (papio ursinus), six african civets (civettictis civetta), six slender mongooses (galerella sanguinea), six honey badgers (mellivora capensis), six large-spotted genets (genetta tigrina), 39 multi-mammate mice (mastomys natalensis), 26 bushveld gerbils (tatera leucogaster) and six pied crows (corvus albus). ...19979261938
stochastic seasonality and nonlinear density-dependent factors regulate population size in an african rodent.ecology has long been troubled by the controversy over how populations are regulated. some ecologists focus on the role of environmental effects, whereas others argue that density-dependent feedback mechanisms are central. the relative importance of both processes is still hotly debated, but clear examples of both processes acting in the same population are rare. key-factor analysis (regression of population changes on possible causal factors) and time-series analysis are often used to investiga ...19979296494
polyamine metabolism in various tissues during pathogenesis of chloroquine-susceptible and resistant malaria.the pathophysiological impact of infections with chloroquine-susceptible (cqs) and chloroquine-resistant (cqr) strains of plasmodium berghei in mastomys natalensis was studied with respect to changes in polyamine profiles in various tissues. both cqs and cqr infections produced similar changes in polyamine profiles of various tissues. maximum increase was recorded in spleen followed by liver and lungs. renal, cardiac and cerebral tissues did not register significant changes. an increase in sperm ...19979415968
fate of infective larvae of brugia malayi in the peritoneal cavity of mastomys natalensis and meriones unguiculatus.the fate of intraperitoneally inoculated infective third-stage larvae (l3) of the nematode brugia malayi lichtenstein and the status of the peritoneal macrophage function were investigated in the susceptible rodent hosts mastomys natalensis roberts and meriones unguiculatus milne-edwards (jird). jirds and m. natalensis were inoculated intraperitoneally with 125 and 250 l3 and the worm burden and peritoneal macrophage function in the two species were compared at different days post-inoculation (d ...19979437845
comparison of the signal transduction pathways activated by gastrin in enterochromaffin-like and parietal cells.gastrin stimulates acid secretion from parietal cells and histamine release from enterochromaffin-like (ecl) cells through identical gastrin receptors. however, gastrin has been shown to have a trophic effect only on ecl cells. the aim of this study was to compare gastrin-induced signal transduction pathways in the ecl and parietal cells of mastomys natalensis, an african rodent.19989649463
interspecies polymorphisms confer constitutive activity to the mastomys cholecystokinin-b/gastrin receptor.the enteroendocrine hormone, gastrin, exerts trophic effects on the gastric mucosa through the cck-b/gastrin receptor (cck-br). to varying degrees in different species, excess circulating gastrin leads to proliferation of enterochromaffin-like cells and to the development of gastric carcinoid tumors. the african rodent, mastomys natalensis, is distinguished from other mammals by its propensity toward cck-br-mediated growth even in the absence of hypergastrinemia. here, we report that the mastomy ...19989786876
histamine metabolism of gastric carcinoids in mastomys natalensis.pharmacological inhibition of gastric acid secretion and subsequent hypergastrinemia in mastomys natalensis is an experimental model well suited for the study of gastric carcinoid formation. the genetic susceptibility of mastomys to develop such tumors is a feature reminiscent of the situation in patients with the men-1 zollinger ellison syndrome, in whom tumor-induced hypergastrinemia, promotes the development of gastric carcinoids. chronic hypergastrinemia, induced by the irreversible h2-recep ...201410461353
the role of endogenous gastrin in the development of enterochromaffin-like cell carcinoid tumors in mastomys natalensis: a study with the specific gastrin receptor antagonist ag-041r.we examined the effects of a newly synthesized gastrin receptor antagonist, ag-041r, on the growth of enterochromaffin-like (ecl) carcinoid tumors in mastomys natalensis both in vitro and in vivo. ag-041r was as potent as the well known gastrin antagonist l365,260 in inhibiting not only the gastrin-induced release of histamine from but also histidine decarboxylase (hdc) gene expression in the ecl carcinoid tumor cells. ag-041r also inhibited gastrin-induced dna synthesis and c-fos gene expressio ...201610461356
altered influence of cck-b/gastrin receptors on hdc expression in ecl cells after neoplastic transformation.gastrin is one of the main factors controlling enterochromaffin-like (ecl) cell endocrine function and growth. long-standing hypergastrinemia may give rise to ecl cell carcinoids in the gastric corpus in man and in experimental models. we have analysed the expression and function of cck-b/gastrin receptors in normal ecl cells and in ecl cell tumours (gastric carcinoids) of the african rodent mastomys natalensis. hypergastrinemia induced by short-term (5 days) histamine2-receptor blockade (loxtid ...199910651065
pdz-dependent activation of nitric-oxide synthases by the serotonin 2b receptor.taking advantage of three cellular systems, we established that 5-ht(2b) receptors are coupled with no signaling pathways. in the 1c11 serotonergic cell line and mastomys natalensis carcinoid cells, which naturally express the 5-ht(2b) receptor, as well as in transfected lmtk(-) fibroblasts, stimulation of the 5-ht(2b) receptor triggers intracellular cgmp production through dual activation of constitutive nitric-oxide synthase (cnos) and inducible nos (inos). the group i pdz motif at the c termi ...200010734074
molecular phylogeny of myomys/stenocephalemys complex and its relationships with related african genera.partial 16s rrna mitochondrial gene sequences were used to infer the phylogenetic relationships among stenocephalemys albocaudata, s. griseicauda and myomys albipes, three closely related ethiopian endemic murines and a selection of related species (myomys daltoni, praomys delectorum, mastomys natalensis, hylomyscus kaimosae, and colomys goslingi) from other african regions. the obtained phylogeny confirms the close relationship between m. albipes and the two stenocephalemys species, but it also ...200111336808
the egyptian mongoose, herpestes ichneumon, is a possible reservoir host of visceral leishmaniasis in eastern sudan.investigations were made on possible reservoir hosts of leishmania donovani in 2 zoonotic foci of visceral leishmaniasis (vl) in dinder national park (dnp) and the peri-domestic habitats of adjacent villages of eastern sudan. animals were captured, in november 1997-1998 and april-may 1999 and examined for l. donovani infection using light microscopy and 2 sensitive polymerase chain reaction (pcr) systems. microscopy and pcr investigations were also used to determine the infection rates of l. don ...200111393826
hosts of the immature stages of the rhinoceros tick, dermacentor rhinocerinus (acari, ixodidae).the collection of the immature stages of dermacentor rhinocerinus from host animals is described for the first time. these are the bushveld gerbil (tatera leucogaster, from which larvae and nymphs were collected, the red veld rat (aethomys crysophilus), from which a larva was collected, and the natal multimammate rat (mastomys natalensis), from which a nymph was collected. the rodents were examined in a nature reserve in which there are white rhinoceroses (ceratotherium simum).200111403434
preferential transcription of a gene for alpha amylase in the carcinoid tumor of african rodent mastomys natalensis.the carcinoid tumor in mastomys natalensis provides a useful animal model of tumorigenesis. we investigated preferentially transcribed genes in this carcinoid tumor by differential hybridization. fourteen clones corresponding to high levels of transcription were isolated from a cdna library. sequencing analysis and a homology search revealed that the clones corresponded to genes for chromogranin and alpha-amylase. high-level transcription of a gene for alpha-amylase gene in mastomys carcinoid tu ...200212071519
isolation and characterization of flagellates from rodents and canids in masinga, machakos district, kenya.a total of 728 animals comprising of 633 rodents and 95 canids were examined for leishmanial parasites. flagellates were isolated from 67 out of 111 (60.4%) acomys subspinosus (spiny mouse), 12 out of 143 (8.4% ) mastomys natalensis (multimammate rat), 2 out of 50 (4.0%) lemniscomys striatus (striped mouse), 2 out of 6 (33.3%) herpestes sanguineus (slender mongoose), 1 of 1 helogale parvula (dwarf mongoose) and 1 out of 84 canis familiaris (domestic dog). all isolates were characterized by isoen ...199512160424
bait bases for mastomys natalensis smith 1834: a murid of public health interest in africa.mastomys natalensis is widely distributed in the whole of africa and is a reservoir of important zoonoses including plague. in order to control this species efficiently using rodenticides, tests were carried out to find the most preferred cereal and bait additives to form a suitable bait base. investigations were based on food choice tests in caged animals. among the cereals tested, rice was significantly preferred (p=0.01) followed by wheat, sorghum and maize. of the additives tested, both sexe ...012160425
the effect of colonisation by helicobacter pylori in praomys (mastomys) natalensis on the incidence of carcinoids.an animal model of experimental gastric helicobacter pylori infection has been developed in the z strain of praomys (mastomys) natalensis; this animal has been reported to develop gastric carcinoids and adenocarcinoma spontaneously. in the present study, male and female mastomys were killed at 1, 2, 4, 8 and 16 weeks after h. pylori inoculation. colonisation of h. pylori was maintained in the stomachs of all animals for up to 16 weeks. h. pylori were mainly found in the antrum. lymphoid infiltra ...200212358069
plague in africa from 1935 to 1949; a survey of wild rodents in african territories.the history of plague in africa during the period 1935-49 is reviewed. much of the information derives from a questionnaire sent to all african territories in 1950. the annual incidence of plague in africa declined, particularly from 1946 onwards. in 1949, under 400 cases were reported, as compared with over 6,000 in 1935. by the end of 1949, plague was still active in the belgian congo, kenya and tanganyika, madagascar, and southern africa. no cases were reported from egypt, tunisia, algeria, m ...195313115987
spontaneous carcinoma of the glandular stomach in a laboratory stock of rattus (mastomys) natalensis. 195513281621
spontaneous carcinoma of the glandular stomach in rattus (mastomys) natalensis, an african rodent. 195713499792
a note of infection of the multimammate rat, rattus (mastomys) natalensis erythroieucus with plasmodium berghei. 195813581637
carcinomas of the glandular stomach and hepatomas in rattus (mastomys) natalensis infected with bilharzia mansoni. 195913649450
the multimammate mouse rattus (mastomys) natalensis: a species for the laboratory investigation of cancer of the glandular stomach. 196113730370
papillary ependymomas produced in rattus (mastomys) natalensis inoculated with vacuolating virus (sv40). 196213972899
production of tumours in rattus (mastomys) natalensis by polyoma virus. 196014435664
intranuclear inclusion in rattus (mastomys) natalensis infected with rat virus. 196114489658
population dynamics of small mammals in semi-arid regions: a comparative study of demographic variability in two rodent species.the seasonally determined demographic structure of two semi-arid rodents, both agricultural pest species (the leaf-eared mouse (phyllotis darwini) in chile and the multimammate mouse (mastomys natalensis) in tanzania), is analysed using capture-mark-recapture (cmr) statistical models and measures for elasticity (the relative change in the growth rate due to a relative unit change in the parameter of concern) derived from projection linear matrix models. we demonstrate that reproduction and survi ...200314561287
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