Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RODENTS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed2006

[Predation and dispersal of Lithocarpus glaber seeds by rodents in Tiantong National Forest Park, Zhejiang Province].

This paper studied the predation and dispersal of Lithocarps glaber seeds by rodents in the Tiantong National Forest Park (29 degrees 48'N, 121 degrees 47'E) of Ningbo City, Zhejiang Province. Five seeds release transects (three in evergreen broad-leaved forest, one in Pinus messoniana forest, and one in shrub), and two seeds release states (covered/uncovered and tagged/untagged) were set up. Iron snare traps were baited to determine the effects of rodents on seeds disappearance. The results showed that two species of rodents, Niviventer confucianus and N. fulvescensi, were the potential predators and dispersers of the seeds. The lost seeds labeled with small piece of tintags could be classified into three categories, i. e., 1) seeds consumed by rodents, with tags stuck seed fragments; 2) seeds cut off from tags, with tags kept only; and 3) both seeds and tags disappeared. The loss rate of seeds was high at the beginning of the observation, and then decreased gradually. The daily seeds disappearance rate (DS-DR) was variable in different habitats, with the highest (1.03%) in evergreen broad-leaved forest and the lowest (0.32%) in shrub. The proportion of these three categories was different, and related with habitat types. The difference of DSDR between covered and uncovered states was statistically significant (P < 0.05), with a higher DSDR under uncovered state. No significant difference was observed between the DSDR of tagged and untagged. The distance of seeds dispersal by rodents was within 6.7 m.

Animals↗
PubMed1991

Susceptibility of laboratory and wild rodents to Rattus or Apodemus-type hantaviruses.

Adult Wistar rats (Rattus norvegicus), Apodemus agrarius, Meriones unguiculatus, Clethrionomys rufocanus, and Apodemus argenteus were inoculated with Rattus-type (SR-11, KI-262, and TB-314) or Apodemus-type (Hantaan 76-118) hantaviruses. Production of serum antibody to the inoculated virus (IAHA titres of 1:32 to 1:4 096) was obsersved in all rodent species 10 weeks after virus inoculation. Rattus-type virus was detected in some organs of all the rodent species employed except of Apodemus agrarius. Apodemus-type virus was found only in some organs of Apodemus agrarius. Newborn Wistar rats induced antibody in high titres to both Rattus- and Apodemus-type hantaviruses. Rattus-type virus was detected in all the organs examined for up to 6 weeks after inoculation, whereas Apodemus-type virus disappeared from all organs except of brain and lung tissues. The virulence of the three Rattus-type viruses to newborn rats was different. These findings indicate that the susceptibility of rodents may vary depending on the combination of rodent species and virus strains; they also suggest that the various species of rodents may be the reservoir animals of hantavirus infection in nature.

Animals↗
PubMedDate not supplied

[The presence of a correlation between erythrocyte acetylcholinesterase activity and body mass in small rodents].

Studies have been made on the activity of erythrocyte acetylcholinesterase in 18 species of wild and laboratory rodents. Significant differences in the enzymic activity unrelated to taxonomic position of rodents were revealed. Negative correlation was found between the enzymic activity and body mass in rodents. The relationship between these parameters for wild rodents is approximated by an allometric equation Y = 1.1 . X-0.73, for laboratory species--Y = 1.5 . X-0.41. It is suggested that the revealed relationship indicates the existence of a connection between the activity of erythrocyte acetylcholinesterase and the intensity of metabolism in small rodents.

Acetylcholinesterase↗
PubMed1988

Cytotoxicity and induction of sister chromatid exchanges in human and rodent brain tumor cells treated with alkylating chemotherapeutic agents.

Rodent (9L and 9L-2) and human (SF-126 and SF-188) brain tumor cells were treated with methylating, ethylating, and chloroethylating nitrosoureas. 9L-2 and SF-188 cells were 10-fold and 5.4-fold more resistant to the cytotoxic effects of 1-(2-chloroethyl)-1-nitrosourea (CNU) than were 9L and SF-126 cells. SF-188 cells were 2.5- to 3-fold more resistant to N-methyl-N-nitrosourea (MNU) and streptozotocin (STZ) than SF-126 cells. 9L-2 cells were slightly more resistant to the cytotoxic effects of STZ and MNU than were 9L cells, but the rodent cells were 5- to 15-fold more resistant to these agents than the human cells. There were only small differences in cytotoxicity among the four cell lines after treatment with N-ethyl-N-nitrosourea (ENU). SF-188 and 9L-2 cells were 7- to 8-fold more resistant to the induction of sister chromatid exchange (SCEs) by CNU than were SF-126 and 9L cells. SF-126 cells were 80-fold more sensitive to the induction of SCEs by both STZ and MNU than were SF-188 cells. Only small differences in SCE induction were observed in 9L and 9L-2 cells treated with MNU and STZ. After ENU treatment, SF-126, 9L, and 9L-2 cells showed similar levels of SCEs; SF-188 cells were more resistant to the induction of SCEs by ENU. Pretreatment of 9L-2 cells with MNU resulted in a dose-dependent increase in cytotoxicity and SCE induction by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Treatment with 1 mM MNU completely reversed the cellular resistance of 9L-2 cells to BCNU but did not potentiate either cytotoxicity or SCE induction in 9L cells. These results suggest that O6-alkylguanine-DNA-alkyltransferase (O6-AT) plays an important role in determining the cytotoxicity of and the induction of SCEs by CNU in both rodent and human tumor cells. O6-AT may also influence the response of human cells to both the cytotoxic effects of and the induction of SCEs by MNU and STZ. In the rodent cells, however, biochemical mechanisms other than O6-AT appear to determine the cytotoxic response to these agents. O6-AT does not appear to influence the cytotoxicity of ENU in either human or rodent cells but may have a small effect on SCE induction in human cells.

Alkylating Agents↗
PubMedDate not supplied

Clinical assessment of laboratory rodents on long term bioassay studies.

The disease status of laboratory rodents should be clinically assessed before the animals are placed on toxicological bioassay programs. This is especially important when the stress of dietary or parenteral intake of toxic substances may trigger the clinical onset of latent diseases in research animals. In clinical evaluation of rodents, the environmental influence on biochemical, physiological and behavioral status of the animals must be continually monitored. Temperature, humidity, ventilation, lighting, and the microenvironment of the cage will all influence, independently or in consort, the response of the animal to various microbial or chemical insults. Unwanted variables in the diet can also markedly after the biological response of the animal and thus alter interpretation of experimental data. Adequately trained personnel, both professional and technical, must be available to provide daily care, clinical observation, and necessary treatment if signs of illness are noted in the laboratory rodent or bioassay experimentation. Clinical signs associated with commonly encountered diseases in laboratory rodents are briefly described. Clinical surveillance and assessment of rodents in part consists of recognition of and detailed recording of clinical signs, coupled with proper diagnostic resources to substantiate clinical observations. It is possible, with proper diagnosis, to evaluate the overall effect of a particular disease on the animal's health, the likelihood that the disease is jeopardizing the health of the other animals on test, and the effect of the disorder on interpretation of experimental results.

Animal Husbandry↗
PubMed1984

Immunological control of chronic Trypanosoma brucei gambiense in outbred rodents.

Recent human isolates of Trypanosoma brucei gambiense generally fail to become or remain patent in laboratory rodents. The purpose of this study was to determine if this was due to acquired immunity and if so which immunosuppressive method was the most efficient in raising parasitemia levels. Prior to infection, rats and mice were immunosuppressed by treatments with cobra venom factor, anti-lymphocyte sera, hydrocortisone acetate, cyclophosphamide; by splenectomy; or by lethal X-irradiation. While no parasites were detected in the blood of most of the untreated rodents for 30 days postinfection, all immunosuppressive procedures resulted in patent parasitemias in at least fifty percent of the treated animals. The most effective method, lethal X-irradiation, consistently caused fulminating infections typical of acute African trypanosomiasis. Cyclophosphamide had the same effect as X-irradiation in rats but was less effective in mice. Splenectomy allowed fulminating first peak parasitemias in two-thirds of the rodents while cobra venom factor and anti-lymphocyte sera in general allowed only low first peaks of parasitemia that were resolved within 10 days of infection. Hydrocortisone acetate allowed low grade and sporadically patent infections throughout the 30-day study. To determine if in untreated rodents, the parasites were eliminated or maintained in a subpatent state, rodents infected for 30-45 days were immunosuppressed with cyclophosphamide.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Parasite-host relations of fleas and rodents].

Not infrequently lice can reach great abundance on rodents. The distribution of lice on animals is uneven. The infection with lice depends not only on the physiological and ecological properties of the host but also on the environmental conditions. The distribution of lice on rodents can be affected by the development of transport communications. If a population of rodents is parasitized by two species of specific lice, they belong to different genera. On single animals only one species of lice occurs as a rule; if two species occur, then one of them is dominant. In this way decreases the interspecific competition between lice. Seasonal and age changes in lice infection are associated with those in host's biology and behaviour under certain climatic conditions. It is clearly displayed in rodents breeding once a year. The infection with lice increase with the rise in rodents abundance. Along with the confirmation of the general rule of poor infection with specific parasites at the borders of the species distribution a case of high infection with lice at the border of the host's distribution was noted. In addition to specific lice, alien species are recorded on small mammals which appear due to exchange of parasites between hosts. Examples are given all conquering new hosts by lice; as a result close species of lice can parasitize phylogenetically distant hosts.

Animals↗
PubMed1980

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 and M. natalensis. Animal food components of all the rodent species comprised mainly insects (especially ants, crickets etc.). Vertebrate flesh and scales were also well represented in the guts of C. gambianus. Domestic and miscellaneous food items were recorded from R. rattus, most of which were trapped in human and animal shelters. Inorganic gut contents, primarily sand grains, were found in sizeable quantities in more than 70% of the rodents examined. Results of experimental feeding trials with caged rodents showed close correlation with those recorded from field samples, especially in terms of food choices and the relative quantities consumed. The ecological and practical implications of these observations are discussed in the light of the importance of the rodents as agricultural and domestic pests.

Animals↗
PubMed1996

Comparative toxicokinetics of methanol in pregnant and nonpregnant rodents.

Methanol toxicokinetics were examined in pregnant Sprague-Dawley rats and CD-1 mice to explore the possibility of gestational-associated alterations in metabolism and disposition. In vitro biotransformation of methanol in rat and mouse fetal livers also was examined to assess the capability of the near-term rodent fetus to metabolize methanol. In the in vivo studies, rats received a single dose (100 or 2,500 mg/kg) of methanol either orally (by gavage) or intravenously; mice received a single oral or intravenous 2500-mg/kg dose. The maximal rate of methanol elimination (Vmax) in vivo decreased at term in both rodent species; Vmax in near-term rats and mice was only 65-80% of that in nonpregnant animals. Gestation also affected intercompartmental transfer rate constants, although there was no obvious relationship between these changes and gestational stage. In vitro metabolism studies supported the in vivo data; adult near-term rodent livers metabolized methanol with a Vmax of approximately 85% that in livers from nonpregnant rodents (p < 0.05). Fetal rodent liver was capable of metabolizing methanol in vitro, but only at a rate < 5% of respective adult livers. Data generated in these experiments demonstrate that alterations in methanol disposition associated with gestational stage must be accounted for in the development of a toxicokinetic model for methanol in pregnant mammals.

Administration, Oral↗
PubMed1996

Rodents, human remains, and North American hantaviruses: risk factors and prevention measures for forensic science personnel--a review.

In 1993, a previously unrecognized hantavirus was identified as the cause for a severe form of respiratory distress later termed Hantavirus Pulmonary Syndrome (HPS). In the past two years, several distinct hantaviruses, of which many are pathogenic, have been found in rodent populations in the US. Rodents shed the virus in their saliva, urine, and feces. Humans usually become infected after inhaling either aerosolized droplets of urine or particulates contaminated with rodent excreta. Rodents, including those identified as hantavirus reservoirs, will often infest and disturb human remains. Forensic science personnel should recognize the potential HPS risks associated with rodent contaminated remains and consider using High Efficiency Particulate Air-filter respirators, disinfectants, and insecticides to minimize risks.

Animals↗
PubMed1976

The isolation and characterization of tumor-specific antigens of rodent and human tumors.

Putative tumor-specific transplantation antigens (TSTA) from both a carcinogen-induced rodent tumor (MC-1) and 2 human tumors were purified. The antigens were solubilized from the tumor cell membranes by limited papain digestion in a manner similar to that described for the isolation of normal histocompatibility antigens. The antitumor immune response of the tumor-bearing host was used to monitor the purification of the putative TSTA in both the rodent and human tumor systems. In the case of the rodent tumor, a major step in the purification of the TSTA involved affinity chromatography on Sepharose beads coupled to autologous antitumor antiserum. A comparable procedure was utilized in the purification of the TSTA from human tumors by using affinity chromatography on anti-human beta2-microglobulin antiserum coupled to a solid phase. The data obtained indicate that the TSTA of human tumors contains a beta2-microglobulin chain that is immunochemically identical with, and very similar in size to, that found in normal human histocompatibility antigens. A subunit of similar size was also identified in the carcinogen-induced rodent tumor. These results suggest that the TSTA in both humans and rodents may well be altered histocompatibility antigens.

Animals↗
PubMed2003

Lymphocytic choriomeningitis virus infection in a province of Spain: analysis of sera from the general population and wild rodents.

Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne virus belonging to the family Arenaviridae, genus Arenavirus, which causes a wide spectrum of human disease. However, data on LCMV infection in Spain is scant. To investigate whether this virus causes infection in Spain, 400 serum samples from the general population (191 males, 209 females) and 100 from wild rodents were studied by immunofluorescence assay (IFA) using L-929 cells infected with LCMV. The study was performed in the "Community of Madrid," a region with both rural and urban areas in different ecological settings. Of the 400 human serum samples tested, antibodies against LCMV were detected in 7 (1.7%). No statistical differences in prevalence were found with respect to either age or rural or urban residence, but differences were seen with respect to sex. Nine (9%) of the rodent serum samples were positive. These results confirm the occurrence of LCMV infections in Man and rodents in Spain.

Adolescent↗
PubMed1983

Plague in South African rodents 1972-1981.

Sera from 3012 rodents of 24 species captured in South Africa during the period 1972-81 were tested for antibody to the Fraction 1 antigen of Yersinia pestis by passive haemagglutination. Antibodies were found in seven (0.23%) rodents of three species. These were Desmodillus auricularis and Tatera brantsii in the northern Cape Province and Rhabdomys pumilio in the eastern Cape Province. Rodents were found positive in 1972, 1974, 1975 and 1979, indicating that plague continues to circulate in rodent populations apparently without causing human cases. The significance of the results is discussed in relation to plague outbreaks in neighbouring countries and to the 1982 outbreak in South Africa.

Animals↗
PubMed1989

The use of a DNA probe for the differentiation of rodent malaria strains and species.

A clone, PCsv4, derived from a partial genomic library of the rodent malaria Plasmodium chabaudi chabaudi AS strain, contains an insert which when used as a probe at low stringency in Southern blotting of genomic DNA from a variety of strains, subspecies and species of rodent malaria parasites, results in a pattern of hybridisation which is specific to each of the DNA samples used, thus providing an accurate method to define a rodent malaria line. The insert only hybridises to DNA derived from malaria parasites of rodent species. The insert also hybridises to a small number of RNA transcripts.

Animals↗
PubMed1993

Borrelia burgdorferi infection in dairy cows, rodents, and birds from four Wisconsin dairy farms.

A combination of culture and subsequent spirochete identification with the polymerase chain reaction technique was used to identify cows, rodents, and birds infected with Borrelia burgdorferi. Animals were trapped on four Wisconsin dairy farms during the summer of 1990. Farms 1 and 2 were located in counties nonendemic for Lyme disease and Farms 3 and 4 were located in counties endemic for Lyme disease. The results of the rodent and bird samples were as follows given as the number yielding organisms number tested: Farm 1, 1/17 Mus musculus and 2/52 Peromyscus domesticus; Farm 2, 4/49 M. musculus, 1/2 P. maniculatus, 1/1 P. leucopus, and 1/35 P. domesticus; Farm 3, 0/27 M. musculus, 0/5 P. leucopus, 0/12 P. maniculatus and, 3/58 P. domesticus; and Farm 4, 1/24 M. musculus, 2/19 P. leucopus, 1/12 Microtus pennsylvanicus, and 0/17 P. domesticus. One P. leucopus and one M. musculus from Farm 2 were pregnant and fetal tissues from both were positive. Cow blood sample results were as follows: Farm 1, 7/47 in July, and 2/45 in August; Farm 2, 0/28 in August and 0/23 in October; Farm 3, 0/13 in July and 1/18 in August 29; and Farm 4, 3/45 in August. Ticks were found on rodents on Farm 4 and on one bird on Farm 3. Spirochetemic cows, rodents, and birds were found in non-Lyme endemic counties suggesting that alternate modes of transmission other than by ticks may be important. Transplacental transmission was shown in M. musculus and P. leucopus.

Animals↗
PubMed2005

PCR-based diagnosis for detection of Leishmania in skin and blood of rodents from an endemic area of cutaneous and visceral leishmaniasis in Brazil.

The technique of polymerase chain reaction (PCR) associated to hybridization was used to screen 123 samples collected from wild and synanthropic rodents captured in a cutaneous and visceral leishmaniasis endemic area in the State of Minas Gerais, Brazil. The detection of Leishmania spp in naturally infected rodents is of fundamental importance for incriminating them as possible reservoir hosts of the diseases in Minas Gerais. A total of 62 specimens belonging to wild (Thrichomys apereoides, Oryzomys subflavus, Galea spixii, Bolomys lasiurus and Wiedomys pyrrhorhinos) and synanthropic (R. rattus) rodent species were captured in different ecotopes. Blood and skin samples were submitted for PCR analyses followed by molecular hybridization with specific probes for the three Leishmania-species complexes. Fifteen samples were found positive after PCR-hybridization and identified as follows: nine belonging to the L. mexicana complex, three to the L. braziliensis complex and three to the L. donovani complex. Positive PCR results were found in 11 out of the 61 (18%) blood samples and in four out of the 62 (6.4%) skin fragments screened. R. rattus and T. apereoides were the most abundant species in the area also presenting high prevalence of natural infection. The presence of parasite DNA belonging to L. braziliensis, L. mexicana and L. donovani complexes was confirmed in several individuals of a rodent species, R. rattus. This work is the first report of the detection of L. (L.) chagasi in a naturally infected T. apereoides. The utility of filter paper as a substrate for PCR analyses and the efficacy of the procedure associated to the hybridization is emphasized.

Animals↗
PubMed2002

Evaluation of an enzyme-linked immunosorbent assay for detection of antibodies to Junin virus in rodents.

Junin virus is the etiological agent of Argentine hemorrhagic fever, a serious rodent-borne disease. An enzyme-linked immunosorbent assay (ELISA) to detect Junin virus IgG antibodies in rodents was evaluated using sera from 27 Calomys musculinus and five Calomys laucha, inoculated experimentally with a live attenuated strain of this arenavirus. The test performance was compared against an indirect immunofluorescence assay (IFA). The ELISA had a sensitivity and specificity of 100% and a reproducibility of 87.9% for samples with titers above the selected cut-off value. IFA had lower sensitivity (53%) with the same specificity. The ELISA results were similar, whether carried out on whole blood or serum samples, thus eliminating the need for serum separation. A high correlation (K=0.86) between ELISA and IFA results was obtained from 1011 wild sigmodontine and murine rodents collected within and outside of the Argentine hemorrhagic fever endemic area. These results indicate that Junin virus IgG ELISA is the most suitable assay for detection of Junin virus antibodies in rodent samples.

Animals↗
PubMed2003

Fungal diseases of laboratory rodents.

Although fungal disease is uncommon in rodents, dermatophytosis is the most common mycosis seen in clinical practice. T. mentagrophytes is the most common etiologic agent, and the guinea pig is the most common species affected, although there are reports in all pet and laboratory rodent species except the gerbil. Despite the low incidence of clinical disease, rodents are common asymptomatic carriers of dermatophytes, and ringworm is the most common zoonotic disease transmitted from rodents to people.

Animals↗