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Biomedical subjects

Y Kudo

Publications and source records attributed to Y Kudo.

At least 235 records · Page 13Linked to original sources
PubMed1992

[An injury of the liver caused by ischemia-reperfusion in rat liver. Report 2: Relationship between the damage of the liver and during the period of reperfusion].

Liver injury by 30-min ischemia following reperfusion was examined biochemically and histopathologically. A greater increase in the level of LDH was observed after 1-hr reperfusion. However, the level of LDH decreased in proportion to the period of reperfusion, while the levels of GOT and GPT were also increased rapidly and reached its peak at 12 hr following reperfusion and were almost restored to the control level by 48 hr. A similar increase was obtained in the lipid peroxides of the liver. In addition, cyt. P-450 content and NADPH cyt. c reductase activity decreased in proportion to the period of reperfusion up to 12 hr and then recovered by 96 hr. On the other hand, heme oxygenase activity was significantly increased by ischemia-reperfusion. The ischemia-reperfused liver resulted in various morphological changes with the period of reperfusion. The destruction of Disse's space, vacuolization of the cytoplasm and nonviable hepatocytes were observed after 12-hr reperfusion. These results indicate the greatest damages of the liver induced by 30-min ischemia following reperfusion is observed after 12-hr or 24-hr reperfusion. The liver injury by ischemia-reperfusion could be a useful experimental model to develop for future studies.

Alanine Transaminase↗
PubMed1992

Attenuation of dysfunction in the ischemia-reperfused liver by glycyrrhizin.

The present study evaluated the effect of glycyrrhizin (GR) on an injury of the liver caused by ischemia-reperfusion in rats. In the liver ischemia-reperfusion model, levels of serum GOT, GPT and LDH activities and lipid peroxides in the liver tissue were significantly increased. On the contrary, total glutathione content in the liver tissue and NADPH cytochrome P-450 reductase activity of liver microsomes were decreased. Pretreatment with GR 20 mg/kg, i.v. 10 min before induction of ischemia resulted in significant decreases in serum GOT, GPT, LDH activities and the lipid peroxide level and a higher tissue glutathione content during the period of reperfusion. Electron microscopic studies revealed various hepatocellular damages with an almost intact sinusoidal endothelium in ischemia-reperfused livers. However, the degree of damage was less severe in the livers from the rats pretreated with 20 mg/kg GR. The results indicate that GR is able to provide partial protection against ischemia-reperfused damage.

Animals↗
PubMed1992

Protective effect of ulinastatin against liver injury caused by ischemia-reperfusion in rats.

The effects of ulinastatin (ULN), a human urinary protease inhibitor, on liver injury caused by ischemia-reperfusion were studied in rats. In the liver ischemia-reperfusion model, ULN suppressed the elevation of serum transaminase levels and tissue lipid peroxide levels in the liver. ULN did not exhibit a radical-trapping action on the superoxide and hydroxyl radicals as measured by electron spin resonance (ESR). ULN suppressed formylmethionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA)-induced superoxide production from polymorphonuclear leukocytes (PMNs) as measured by the cytochrome c assay. ULN did not inhibit either xanthine oxidase (XO) activity or the conversion of xanthine dehydrogenase (XDH) to XO during the ischemic period. ULN also strongly protected against the hypotonic hemolysis of rat erythrocytes. These results suggest that ULN's membrane stabilizing action and suppressive effect against PMNs superoxide production might be attributed to its suppressive effect on the liver's lipid peroxidation caused by ischemia-reperfusion.

Animals↗
PubMed1992

[A study of the humoral immunity of mice injected with beryllium chloride].

We studied changes of humoral immunity, such as complement pathway activity, C3 contents and contents of immunoglobulin, in mice injected subcutaneously with BeCl2 or CuCl2 once a week for 12 weeks. Mean body weights of JCL: ICR female mice were approximately 30g in control mice (control group; n = 7), in mice injected with Be (Be group; n = 8) and in mice injected with Cu (Cu group; n = 8). Values of classical complement pathway activity (CH50) were 18.8 +/- 1.4 U per ml, 15.3 +/- 1.8 U per ml and 16.7 +/- 1.3 U per ml in the control group, Be group and Cu group, respectively. The CH50 values of Be and Cu groups were significantly lower than that of the control group (P < 0.01). In contrast, values of alternative complement pathway activity (ACH50) and contents of C3 were almost constant in the three groups. The immunoglobulin content in the Be group tended to increase. The activity of alanine aminotransferase in the Be group was markedly higher than that in the control group (P < 0.05), and the aspartate aminotransferase activity was also high. The CH50 value of mice injected with a small amount of Be once a week over a 12-week period decreased markedly, although either the ACH50 value or C3 content was the same as in the control group. The immunoglobulin content somewhat increased in the Be group. These results suggest the possibility that immune complex is induced by Be.

Animals↗
PubMed1992

The use of bovine anti-PMSG serum in beef cattle after PMSG-superovulation.

Thirteen beef cows were superovulated using 4,000 i.u. of pregnant mare serum gonadotrophin (PMSG) on days 9 to 14 of the estrous cycle, followed by two injections of 500 micrograms prostaglandin F2 alpha analogue (PGF2 alpha) 48 and 55 hrs later. Seven of them were injected intramuscularly with bovine anti-PMSG serum 12 hrs after the first signs of estrus. The remaining 6 cows were served as controls and received no antiserum. Peripheral blood concentrations of progesterone (P) and estradiol-17 beta (E2) were compared in relation to the superovulatory responses. The injection of anti-PMSG serum did not significantly affect the numbers of the corpora lutea (CL), the anovulatory follicles and the transferable embryos at 7 to 8 days after superovulatory estrus, but increased the ratio of embryos classified as excellent or good quality. Although the plasma P concentration showed no significant differences between the anti-PMSG-treated and control cows, the plasma E2 concentration displayed a characteristic difference, suppressing the second E2 peak in the anti-PMSG-treated cows. It is concluded that the use of bovine anti-PMSG serum for PMSG/PGF2 alpha-treated cows at 12 hrs after the beginning of the estrus improves the quality of embryos recovered, probably due to inhibition of high estrogenic environment following ovulation.

Animals↗
PubMed1992

[Determination of protoporphyrins in blood using HPLC. Standardization of protoporphyrins and interlaboratory comparison of analyses].

1) In order to compare the results of determination of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZP) using HPLC, the preparation procedures for standard solutions of PP and ZP were studied at four laboratories. According to the methods mutually agreeable to the four laboratories, the absorption values using UV-Vis spectrometer from the 4 laboratories were found to be identical. 2) The total of 28 whole blood samples obtained from the same workers whose Pb-B levels ranged from 2.9 to 87.9 micrograms/dl were sent to the 4 laboratories for determination of PP and ZP. The laboratories were allowed to use their own HPLC apparatus, column, mobile phase and fluorometric detectors, although the same procedures were used to prepare the standard solutions of PP and ZP. The results showed that significant biases in ZP and PP levels were found between two out of the 4 laboratories, but the ZP values corrected by the recovery rate showed no statistical difference among the laboratories. 3) Blood levels of ZP, total protoporphyrin (TP, calculated by PP+ZP/1.1), and PP determined by HPLC method correlated well with free erythrocyte protoporphyrin (FEP) determined by the method of extraction into the acidic solvent. The correlation coefficients between Pb-B and log TP, ZP, FEP or PP were 0.82-0.84, 0.80-0.83, 0.786, or 0.70-0.73, respectively. 4) The coincident ratios of PP/TP obtained at 4 laboratories ranged from 12.1 to 19.0%. These values were within a relatively narrow range, although two different kinds of organic solvents (DMF: N',N'-dimethylformamide or Methanol/triton-X 100) were used in the extraction steps.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1992

The mouse ligated intestinal loop assay for the studies on enteroinvasive Escherichia coli.

Enteroinvasive Escherichia coli exhibited a positive reaction in the mouse intestinal loop assay except for noninvasive mutant strains. These mean values of fluid weight per gut length of mouse loops inoculated with enteroinvasive E. coli were significantly higher than that given by brain heart infusion broth. Oedema and swelling in all positive loops, increased bacterial cell numbers within intestinal loops were observed.

Animals↗
PubMed1991

A significant increase in intracellular Ca2+ concentration induced by (2S,3R,4S)-2-(carboxycyclopropyl)glycine, a new potent NMDA agonist, in cultured rat hippocampal neurons.

The increase in intracellular Ca2+ concentration, [Ca2+]i, induced by isomers of 2-(carboxycyclopropyl)glycine (CCG) was examined in cultured rat hippocampal neurons. Some CCG isomers and N-methyl-D-aspartate (NMDA) increased [Ca2+]i in a concentration dependent manner. The 2S,3R,4S isomer of CCG (L-CCG-IV) was the most potent in elevating [Ca2+]i, and its activity was more than 100 times higher than that of NMDA and about 10 times higher than that of L-glutamate. The increase in [Ca2+]i was effectively blocked by NMDA blockers and Mg2+, and was markedly augmented by the addition of a low concentration of glycine. L-CCG-IV would be a useful tool for elucidation of functions of NMDA receptors.

Amino Acids, Dicarboxylic↗
PubMed1991

Specific cholinergic destruction in the basal magnocellular nucleus and impaired passive avoidance behavior of rodents.

A nerve growth factor (NGF)-diphtheria toxin conjugate (NGDT) was found to selectively abolish or depress the activity of NGF receptor-bearing cholinergic neurons of the basal magnocellular nucleus (BMN). Bilateral cortical injections of NGDT impaired the retention of passive avoidance behavior in mice. A memory deficit was also revealed when cortical injections of NGDT were administered after the acquisition of a passive avoidance response. Thus, retrograde destruction of BMN cholinergic neurons by the cortical injection of NGDT interfered with both learning and memory processes. The animal model outlined here should be useful in analyzing the pathogenesis of Alzheimer's disease and the functions of the cholinergic system in the BMN.

Animals↗
PubMed1991

Alterations in intracellular calcium transients of fibroblasts from progressive systemic sclerotic patients: a digital imaging microscopic study.

Intracellular Ca2+ concentrations ([Ca2+]i) in cultured skin fibroblasts from normal subjects and progressive systemic sclerosis (PSS) patients were determined by using Fura-2 and fluorescent videomicroscopy. With the exception of fibroblasts from one PSS patient showing a higher [Ca2+]i, no significant difference was observed in resting [Ca2+]i between the two groups of fibroblasts. Bradykinin (BK) (10 microM) induced a transient [Ca2+]i increase in normal fibroblasts, whereas the BK-induced [Ca2+]i increase was reduced or not detectable in PSS fibroblasts. Removal of extracellular Ca2+ did not eliminate the BK-induced [Ca2+]i increase in normal fibroblasts. These findings suggest that BK stimulates Ca2+ release from intracellular stores in human fibroblasts, and also that the BK-mediated Ca2+ release is impaired in PSS fibroblasts.

Adult↗
PubMed1991

Developmental assembly of calcium-mobilizing systems for excitatory amino acids in rat cerebellum.

The postnatal development of calcium-mobilizing systems was studied by both microfluorometric imaging analysis of Ca2+ on living rat cerebellar slices and immunohistochemical labeling of phosphatidylinositol 4,5-bisphosphate (PIP2) and inositol 1,4,5-trisphosphate binding protein (IP3BP) in fixed rat cerebellum. Stimulation with quisqualate (QA) or N-methyl-D-aspartate (NMDA) enhanced the Ca2+ level only diffusely on postnatal day (PND) 3, but more discretely on PNDs 7 and 15. On PND 21, QA-induced responses were localized in the molecular layer especially, but not in the granular layer. By contrast, NMDA mobilized Ca2+ prominently in the granular layer, but only weakly in the molecular layer. Localized expression of PIP2 in the molecular layer paralleled QA-induced Ca2+ mobilization, but IP3BP was expressed more diffusely. The present study offers the first direct evidence that PIP2, but not IP3BP, is essential for QA-induced Ca2+ mobilization in the cerebellar cortex.

Amino Acids↗
PubMed1991

A 'macro' image analysis of fura-2 fluorescence to visualize the distribution of functional glutamate receptor subtypes in hippocampal slices.

The distribution of functional glutamate receptor subtypes was visualized as regional changes in intracellular Ca2+ concentration induced by administration of a specific agonist for each subtype. An image of the fura-2 fluorescence from a whole hippocampal slice was directly excited at 340 or 380 nm through an optical fibre and observed via a low-magnification objective lens (x4). A heterogeneous distribution of N-methyl-D-aspartate (NMDA) and non-NMDA subtypes was demonstrated by the ratio of fluorescence intensities before and after administration of each agonist. This 'macro' image analysis can reveal distributions of multiple functional receptors in a living brain slice.

Animals↗
PubMed1991

Catecholamine and acetylcholine in the rat cerebral cortex with special reference to pathogenetic mechanisms of Alzheimer's disease.

A direct synapse between catecholamine fibers and neuropeptide Y-containing neurons is demonstrated in rat cerebral cortex using an immunohistochemical double-staining method under the electron microscope. A new method to produce a selective reduction in cholinergic neurons in the basal forebrain without damage to the non-cholinergic neurons, passing fibers or other cholinergic systems, is described. This animal model seems to be very useful to analyze the pathogenesis of Alzheimer's disease and to examine the function of cholinergic neurons of the basal forebrain.

Acetylcholine↗
PubMed1991

[An injury of the liver caused by ischemia-reperfusion in rat liver].

Cellular damage of various organs by ischemia following reperfusion is assumed to be at least in part due to lipid peroxidation in biomembranes, and oxygen-derived free radicals play a major role. The level of lipid peroxides in liver tissue increased during 90-min ischemia. When reflow of hepatic blood was allowed, a greater increase in the lipid peroxides was observed. Similar increases were obtained in several serum markers (GOT, GPT and LDH) during the period of ischemia or ischemia-reperfusion. In addition, levels of cytochrome p-450 and NADPH cyt. c reductase activity decreased in proportion to the decrease in microsomal proteins during ischemia or ischemia-reperfusion. On the other hand, superoxide dismutase in blood was significantly increased by ischemia-reperfusion. Rats died within 2 days after liver ischemia of 90 min, while all animals subjected to 30-min ischemia survived. Histopathological examinations indicated that extensive coagulation with erythrocytes occurred and the extent was dependent on the time of ischemia. The liver injury by ischemia-reperfusion could be a useful experimental model for studying liver injury induced by free radicals, for developing hepatoprotective drugs, or for investigating liver transplantation.

Alanine Transaminase↗
PubMed1991

[Effects of kamikihi-to, a Chinese traditional medicine, on various cholinergic biochemical markers in the brains of aged rats].

The effects of kamikihi-to (EK-49) on various cholinergic biochemical markers, muscarinic receptors, acetylcholinesterase (AChE), choline acetyltransferase (CAT) and choline uptake, in aged rat brains were examined. Administration of kamikihi-to in daily doses of 200 mg/kg, p.o. for 4 weeks to aged rats (24-months-old) significantly increased the density of muscarinic receptors (Bmax) for 3H-QNB (quinuclidinyl benzilate), but did not affect the apparent dissociation constant (Kd). After repeated administration of kamikihi-to to aged rats, AChE activity and choline uptake were not significantly different in the kamikihi-to treated aged rats as compared with the control aged rats. However, administration of kamikihi-to for 4 weeks resulted in a significant increase in Vmax values of CAT in kamikihi-to treated aged rats as compared with those of the control rats. These results indicate that long-term treatment with kamikihi-to enhances both the Bmax and Vmax for QNB binding and CAT activity in aged rats, respectively.

Acetylcholinesterase↗