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141.
Hamster embryos were treated with various doses of NaNO2 in utero, by its oral administration to the mothers, and then the embryonic cells were examined for micronucleus formation, chromosomal aberrations, morphological or malignant transformation and drug-resistant mutations. For induction of resistant mutations, the cells were cultured in normal medium for 72 h, and then selected in media containing 8-azaguanine (10 or 20 microgram/ml) or 1 mM ouabain. This treatment with NaNO2 caused marked dose-dependent induction of 8-azaguanine- and ouabain-resistant mutations. Cultured embryonic fibroblasts in the resting state also showed a marked dose-dependent increase in micronucleus formation but not an increase in chromosomal aberrations. This treatment also caused morphological and neoplastic transformation of the cells. Transplacental oral treatment with DMN, as a positive control, caused changes of similar extent in biological effects of embryonic fibroblasts, and in addition it caused chromosomal aberrations in metaphase plates. On the contrary, transplacental oral application of NaNO2 did not induce any biological change in cultured embryonic fibroblasts. 相似文献
142.
Analysis of population changes by measurement of body weight in the Koshima troop of Japanese monkeys 总被引:5,自引:0,他引:5
Akio Mori 《Primates; journal of primatology》1979,20(3):371-397
Measurements of the body weight of monkeys in the Japanese monkey troop on Koshima islet in southern Japan have been made
since 1970. Population changes in the troop have been recorded since 1952. The population changes were further analyzed on
the basis of the body weight changes of the troop members. The recent history of the Koshima troop can be divided into three
periods differing according to conditions of artificial feeding: (1) a semi-wild period (SW Period, 1952–63); (2) an artificial
feeding period (AF Period, 1964–71); (3) and a restricted artificial feeding period (Non-AF Period, 1972–77). The AF Period
represented a period of population growth, whereas the Non-AF Period was a declining one when the population density of the
troop was roughly ten times that of most wild troops. These population changes, i.e., changes in population parameters especially
in the population declining phase, could be fairly well understood from the general features of the body weight changes of
the troop members, the slow body weight growth, elevation of age at first birth, and small size of adult females. Reproduction
and survival were affected by seasonal and yearly changes in body weight. The pattern of changes in body weight displayed
seasonal peaks in the autumn and spring. Of these, the former suggests that fruit eating in the autumn is an important factor
in the reproduction and growth of the monkeys. 相似文献
143.
In order to study the regulatory mechanism of motilin release, plasma motilin was measured in healthy dogs during the fasting state and after the ingestion of ordinary nutrient. Fasting plasma motilin levels were found to fluctuate intermittently, but ingestion of a meal completely abolished the intermittent motilin release and resulted in low motilin levels lasting for 6–8 h. To clarify the role of the duodenum in this motilin release, an operation was performed in five dogs by which we excluded from the alimentary tract the upper half of the small intestine not including the duodenum from a point 2 cm below the larger pancreatic duct. After this operation meal ingestion still caused a decrease in plasma motilin levels. However, after a modified version of the operation was performed in 5 other dogs by which the upper half of the small intestine together with the duodenum was transected at the pyloric ring, plasma motilin was not suppressed by meal ingestion. These results suggest that motilin secretion is regulated by nutrient ingestion and that the passage of nutrients through the duodenum plays a important role in its regulation. 相似文献
144.
Distribution and characterization of cyclo(His-Pro)-like immunoreactivity in the rat gastrointestinal tract 总被引:1,自引:0,他引:1
M Mori J Pegues C Prasad R M Edwards J F Wilber 《Biochemical and biophysical research communications》1982,109(3):982-987
The distribution of cyclo(His-Pro), thyrotropin-releasing hormone (TRH) and activity was examined in the rat gastrointestinal (GI) tract. Cyclo(His-Pro)-like immunoreactivity was present in the following order of distribution (fmoles/mg protein): caecum > colon = jejunum = ileum > stomach = duodenum = rectum, and was immunologically and chromatographically identical with the authentic cyclo(His-Pro). Cyclo(His-Pro) concentrations showed significantly positive correlations with TRH concentrations, but not with activities, in most tissues of the GI tract, suggesting a precursor role of TRH for gut cyclo(His-Pro). These data suggest that cyclo(His-Pro) may be involved in regulating rat GI functions. 相似文献
145.
Hepatocyte lysosomes, mitochondria, and peroxisomes show a dramatic translocation during mitosis induced by partial hepatectomy. During prophase, all three organelles move to the perinuclear cytoplasm. In metaphase, they become concentrated in the polar regions. During telophase, these organelles form clusters in the juxtanuclear regions. This organelle translocation is inhibited by the administration of a low concentration of colchicine, suggesting an involvement of microtubules in their movement. 相似文献
146.
Both induction and activation of the branched-chain 2-oxo acid dehydrogenase complex in primary-cultured rat hepatocytes by clofibrate 总被引:1,自引:0,他引:1
Clofibrate administration to rats caused both the activation and induction of the branched-chain 2-oxo acid dehydrogenase complex in the liver; the former phenomenon occurred within the first 6 h after clofibrate administration whereas the latter occurred after 12 h. Essentially the same results were obtained with primary cultures of rat hepatocytes in the presence of 0.5 mM clofibrate, though about three-fourths of the enzyme complex in control cells (without clofibrate addition) was inactivated during a culture for 44 h, with little reduction of the enzyme amount. This was also confirmed by immunotitration analysis with antibodies raised against the purified decarboxylase and transacylase components of the enzyme complex. On the other hand, the activity of dihydrolipoamide dehydrogenase (a constituent of the complex) was little affected by clofibrate administration. The half lives of the decarboxylase and transacylase components in the primary cultures were estimated to be in the range of 22-26 h, and were unchanged in the presence of clofibrate, when determined with the use of cycloheximide and by a pulse-chase experiment. On the contrary, the rates of synthesis of these two enzyme components had increased to about 1.9-fold after 32 h cultivation in the presence of clofibrate. Thus, the increase in the synthesis of both the components resulted in induction of the complex. 相似文献
147.
H Koga N Mori H Yamada Y Nishimura K Tokuda K Kato T Imoto 《Journal of biochemistry》1991,110(6):939-944
We found that rat cathepsin H showed strong transacylation activity under physiological conditions. It is a feature of cathepsin H to utilize amino acid amides not only as acyl-acceptors but also as acyl-donors in the reaction. The pH-dependence of the transacylation activity was distinct from those of other papain-superfamily proteases. The alkaline limb (pKapp = 7.5) could be regarded as the pKa of the alpha-amino group of the acyl-donor, which was also involved in the original amino-peptidase activity. The acidic limb (pKapp = 5.8) was suggested to be involved in the deacylation step, where amino acid amide attacked the acyl-intermediate as a nucleophile in place of water in the hydrolysis. Although the N alpha-deprotonated acyl-acceptor, which is supposed to govern the nucleophilic attack, has a small population in the acidic pH range (above pH5), the transacylation was detectable even at the acidic pH-range because of the high S1'-site binding ability and suitable nucleophilicity of the acyl-acceptor. In the transacylation between various amino acid amides, the S1 and S1' site appeared to prefer hydrophobic residues without and regardless of a branch at beta-carbon, respectively. From these results and the sequence homology in the papain superfamily, we concluded that the reaction was governed by the acyl-donor having a protonated amino group, the acyl-acceptor having a deprotonated amino group and the remarkable hydrophobic character (especially favoring tryptophan amide) of the S1' site, presumably reflecting the good conservation of Trp177 in papain-superfamily proteases. 相似文献
148.
149.
K Kajita K Yasuda N Yamakita T Murai M Matsuda H Morita A Mori M Murayama S Tanahashi M Sugiura 《Endocrinologia japonica》1991,38(2):121-129
In an attempt to investigate the clinical significance of anti-pituitary antibodies in patients with hypopituitarism, anti-pituitary antibody in plasma was examined in 10 such patients (7 cases of isolated ACTH deficiency, 1 of partial hypopituitarism, and 2 of Sheehan's syndrome), on two or three occasions with an interval of more than 6 months (longitudinal study). In a total of 16 relatives of these 4 patients (2 cases of Sheehan's syndrome, one in each of partial hypopituitarism and isolated ACTH deficiency) and one patient not involved in the longitudinal study, anti-pituitary antibodies were also examined (family study). Anti-pituitary antibodies reacting with rat pituitary cytoplasmic antigens (pituitary cell antibodies: PCA) and pituitary cell surface antibodies (PCSA) reacting with GH3 cells and/or AtT-20 cells were measured with indirect immunofluorescence. The longitudinal study revealed the disappearance of antibodies in 3 patients, 2 PCA positive and one both PCA and PCSA positive. In 3 patients, altered antibody titers or a newly appearing antibody were found during the follow-up period. In 4 patients, the pituitary antibodies were negative during the follow-up periods. Of 16 family members studied, positive PCA was found in 3 members (2 in the families of patients with PCA positive Sheehan's syndrome, and 1 in the family of the patients with PCA positive partial hypopituitarism). Positive PCSA was found in 4 members (one in each of families of patients with partial hypopituitarism and isolated ACTH deficiency and of two cases of Sheehan's syndrome), and weakly positive PCSA was found in one family member of a patients with PCA positive Sheehan's syndrome.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
150.
Maturation-promoting factor and a homolog of fission yeast cdc2+ gene product (p34cdc2) were investigated during the final 24 hr of maturation of quail oocytes. Kinase activity of p34cdc2 in the oocyte germinal disk (GD) increased 15 times at maturation. Two bands, at 32 and 34 kDa, were detected in immature oocytes by immunoblotting of SDS-PAGE with anti-p34cdc2 monoclonal antibody. A new band, which is close to the 32-kDa band but with a slightly faster mobility, appeared during maturation. No p34cdc2 could be detected outside the GD. Microinjection of GD extract from mature oocytes caused maturation of Xenopus oocytes. 相似文献