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Biomedical subjects

K Yagami

Publications and source records attributed to K Yagami.

At least 73 records · Page 4Linked to original sources
PubMed1993

Comparison of plasma endotoxin levels in germ-free, SPF and conventional laboratory animals (mice and rats).

Plasma endotoxin levels were examined in laboratory mice and rats sustained under germ-free (GF), SPF and conventional (CV) conditions. The values were 1.72 (GF mouse), 2.67 (SPF mouse), 2.44 (CV mouse), 2.05 (GF rat), 2.56 (SPF rat), and 3.13 pg/ml (CV rat). The GF animals showed the lowest levels, followed by SPF and CV animals, in that order. When SPF animals were transferred into the conventional condition (conventionalization), the plasma endotoxin levels changed slightly, but not significantly. The present study demonstrates that the levels of plasma endotoxin in healthy laboratory animals are relatively stable and are not affected by microbiological conditions.

Animals↗
PubMed1993

[Comparison between the blood from orbital sinus and heart in analizing plasma biochemical values--increase of plasma enzyme values in the blood from orbital sinus].

Plasma biochemical values, blood urea nitrogen (BUN), glucose, aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine phosphokinase (CPK), were compared between the samples collected from orbital sinus, heart and tail vein in mice, rats and hamsters. The significant higher values of AST, LDH and CPK were shown in samples from orbital sinus as compared with that from other sites. The blood from orbital sinus was bleeding by two methods and compared in the plasma enzyme values. It is suggested that the leakages of these enzymes from destroyed ocular tissues result in the increase of the plasma enzyme values.

Animals↗
PubMed1993

Serological evidence of pneumonia virus of mouse (PVM) infection in laboratory rats.

PVM specific antibody was determined using 3 serological tests (Parker's original hemagglutination-inhibition [HI] test, modified HI test, and indirect fluorescent antibody [IFA] test). IFA test was found to be the most sensitive method, so that IFA test was considered to be the method of choice for a small scale microbiological monitoring in animal facilities. A total of 1,280 sera including rats, mice, hamsters and rabbits were tested for PVM antibody. The prevalence of PVM antibody was 17.2% (116/674) in conventional rats and 30.0% (160/200) in SPF rats obtained from commercial breeders and research facilities. Furthermore, two samples of 144 conventional rabbits (1.4%) were showed specific antibody positive to the virus. However, hamsters and mice showed no evidence of PVM infection. These results suggest that PVM infection is prevalent, especially in laboratory rats in Japan.

Animals↗
PubMed1993

Isolation of Salmonella from impounded dogs introduced to a laboratory.

Isolation of Salmonella from the feces of impounded dogs was carried out to make clear the recent microbiological condition of dogs introduced into our facilities. Salmonella was isolated from 10 out of 283 samples (3.5%). Inparticular, during the first week after introduction, Salmonella was isolated from nine out of 74 dogs (12.2%). The isolation rate during the first week after introduction was significantly higher than that for dogs introduced later. No isolates were detected from dogs reared for more than 3 weeks after introduction. This study indicates that impounded dogs had the highest risk of infecting a person with Salmonella during the first week after introduction into our laboratory animal facilities, and that we need to pay attention to this fact when handling them.

Animals↗
PubMed1993

Dependence of angiotensin production in transgenic mice carrying either the human renin or human angiotensinogen genes on species-specific kinetics of the renin-angiotensin system.

In order to study the functional role of the renin-angiotensin system in the control of blood pressure, projects were initiated using transgenic mice carrying either the human renin gene or the human angiotensinogen gene. To extend the usefulness of the transgenic model system of hypertension research, a two-tiered strategy for generation of transgenic mice with high blood pressure has been developed. This unique system allows the establishment of transgenic lines with a strict species specificity of the renin-angiotensinogen reaction exhibited by transgene products that are regulated in a tissue specific manner. In this report, the strategy concerning the "two-tiered method" is presented and evidence is provided the overproduction of angiotensin occurs only in the combined reaction with human renin and human angiotensinogen expressed in transgenic mice.

Amino Acid Sequence↗
PubMed1992

Vertical transmission of HTLV-1 in HTLV-1 carrier rat.

A female F344 rat was injected with 2.4 x 10(6) MT-2 cells intravenously at 3 and 4 weeks old, and was mated with a non-infected male rat at the 17th week after injection, when the dam rat contained HTLV-1 provirus in the peripheral blood mononuclear cells as determined by polymerase chain reaction. HTLV-1 provirus was detected in at least 2 out of 9 offspring. This system should be useful for studies on the routes and prevention of vertical transmission and on elimination of once-transmitted HTLV-1.

Animals↗
PubMed1992

Species-specific kinetics of mouse renin contribute to maintenance of normal blood pressure in transgenic mice with overexpressed human angiotensinogen.

Angiotensinogen, the precursor of a vasoactive octapeptide angiotensin II, is the only known natural substrate of renin, and its reaction exhibits strict species specificity and is the rate-limiting step in the renin-angiotensin system that controls the blood pressure. We measured blood pressure and heart rate of the transgenic mice with overproduced human angiotensinogen, and showed no significant difference in these parameters between transgenic and nontransgenic mice. We also provided evidence that mouse renin could not cleave human angiotensinogen, indicating a lack of angiotensin production from the human substrate. These results suggested that the blood pressure of transgenic mice is normally maintained, probably due to the inability of mouse renin to release angiotensin from the transgene products.

Angiotensinogen↗
PubMed1992

Development of mouse oocytes superovulated at different ages.

The development of oocytes superovulated at 25, 50, or 90 days in four mouse strains (C57BL/6N, DBA/2N, ICR, and B6D2F1) was examined using the techniques of in vitro fertilization, culture, and transfer of two-cell embryos to pseudopregnant recipients. The highest number of ova were obtained from superovulated 25-day-old mice in all strains. Approximately 80% of oocytes developed to the two-cell stage after in vitro fertilization. Of these living oocytes, 60% developed to weanling stage through the recipient. These results suggested that donor age among 25, 50, or 90-day-old mice has no influence on the viability of superovulated oocytes. Consequently, we conclude that superovulated 25-day-old mice offer an economical and efficient source of viable oocytes for the production of transgenic mice.

Age Factors↗
PubMed1991

Pathogenesis of a newly isolated rat virus in newborn and juvenile rats.

The pathogenesis of the UT-1 strain, a newly isolated rat virus (RV), in juvenile and newborn rats was examined. Intracerebrally (ic) inoculated newborns developed severe pantropic infections resulting in emaciation, stunted growth, diarrhea, dehydration and icterus, and died 13 to 15 days after the inoculation. Newborns inoculated intraperitoneally (ip) developed similar, but milder diseases. The virus replicated in all the organs tested, which was followed by severe viremia. Histopathologically, diffuse vacuolation and necrosis of the hepatocytes were observed in the liver. Juvenile rats inoculated with the virus showed neither clinical signs nor histopathologic lesions, although viral recovery and antibody production were observed. Thus, we conclude that the UT-1 strain of RV caused asymptomatic infections in juvenile rats, and fatal infections with hepatic lesions in newborn rats.

Age Factors↗
PubMed1991

The advantage of enzyme-linked immunosorbent assay (ELISA) as a method of microbiological monitoring for rat virus (RV).

An enzyme-linked immunosorbent assay (ELISA) was tested to detect antibodies against rat virus (RV). The purified ELISA antigens were prepared from rat embryonic cells infected with RV-13 (prototype strain) and UT-2 (Japanese isolate), respectively. Western blotting analysis confirmed that both of these antigens had three structural polypeptides (81 K, 61 K, and 59 K). Eleven laboratory and wild rat colonies in Japan were tested for rat virus contamination, serologically. No significant differences in the sero-positive ratio and the distributions of ELISA titers were demonstrated in the ELISA, using antigens from RV-13 and UT-2. ELISA was more sensitive and specific for detecting antibodies against RV from rat serum rather than hemagglutination inhibition (HI) test. This study also confirmed that the RV contaminated widely in colonies of laboratory and wild rats in Japan, and suggested that RV would have to be checked during the microbiological monitoring of laboratory rats.

Animals↗
PubMed1991

Spontaneous leukemia occurring in aged Slc: Wistar rats and its transplantation into rats.

Spontaneous leukemia occurred in 36% of a group of 39 aged Slc: Wistar rats, which ranged in age at death from 99 to 123 (average age: 114) weeks old. The leukemic rats showed hemolytic anemia, jaundice and leukocytosis (21,000 to 360,000/mm3). Macroscopically, they were characterized by splenomegaly and hepatomegaly. The leukemia cells were rich in basophilic cytoplasm containing eosinophilic granules. Their nuclei were oval and occasionally revealed mitotic figures. These leukemia cells were consistently transplantable into both Slc: Wistar and F 344/NSlc rats. In the transplanted cases, the latency and survival periods were prolonged in proportion to decreases in the inoculated cell dose.

Animals↗
PubMed1988

Morphobiochemical analysis of calcified chondroblastic osteosarcoma of the mandible.

Although the morphological features of osteosarcoma have been widely investigated, there is little information about its biochemistry. In this study, materials obtained from human calcified chondroblastic osteosarcoma were analyzed by microanalytical techniques revealing both morphological and biochemical characteristics at the same tissue site. Morphologically, tumor cells in the surface area showed atypical and mitotic figures. Hypertrophic chondroblastic cells appeared and increased in density closer to the calcified region. Almost all cells in the calcified region were hypertrophic. Biochemical analysis revealed that alkaline phosphatase activity was steeply elevated and inorganic phosphate gradually increased towards the calcified region. The spread of the calcified region was coincident with the contents of acid-soluble phosphate and calcium of the tumor. These results were similar to those found in endochondral calcification of epiphyseal growth cartilage.

Alkaline Phosphatase↗
PubMed1988

Virucidal efficacy of physico-chemical treatments against coronaviruses and parvoviruses of laboratory animals.

Virucidal efficacy of chemical disinfectants, heating and ultraviolet radiation against mouse hepatitis virus (MHV), canine coronavirus (CCV), Kilham rat virus (KRV) and canine parvovirus (CPV) were examined. Coronaviruses (MHV and CCV) were inactivated by ethanol, isopropanol, benzalkonium chloride, iodophor, sodium hypochlorite, sodium chlorite, cresol soap and formaldehyde as well as by heating at 60 degrees C for 15 minutes, whereas parvoviruses (KRV and CPV) appeared to be inactivated by disinfectants such as formaldehyde, iodophor, sodium hypochlorite and sodium chlorite. Parvoviruses were stable under heating of up to 80 degrees C for 30 minutes. Ultraviolet radiation inactivated all viruses within 15 minutes. No significant differences in stability against physico-chemical treatments were seen between viruses in the same group.

Animals↗