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Biomedical subjects

N Hashimoto

Publications and source records attributed to N Hashimoto.

At least 559 records · Page 31Linked to original sources
PubMed1988

Role of maternal antibody in protection from hemorrhagic fever with renal syndrome virus infection in rats.

The effect of maternal antibody on the protection of newborn rats from infection of HFRS virus strain SR-11 was examined. Antibody to HFRS virus was transferred from immune dams to their offspring prenatally as well as postnatally. IgG antibody was detected in the sera of fetuses by IFA test (titers from 1:64 to 1:256) and in fetal fluids (1:32) obtained from the uteri of immune dams at 20 days after mating. In the sera of the newborn, IgG titers of maternal antibody ranged from 1:64 to 1:256 just after birth, reached a peak titer around 1:2,048 at 2 weeks after birth, then declined and disappeared at about 8 weeks of age. No IgA and IgM antibodies were detected in the sera of fetuses and newborns. After intraperitoneal challenge by strain SR-11 (10(2.2) LD50), death and infection of 2-day-old rats from immune dams were prevented by the presence of maternal antibody. The protective effect of maternal antibody remained in 8-week-old rats having an IFA titer of maternal antibody as low as 1:16, and even in some 10-week-old rats with negative tests for maternal antibody.

Aging↗
PubMed1988

Regulation of meiotic metaphase by a cytoplasmic maturation-promoting factor during mouse oocyte maturation.

During mouse oocyte maturation the regulation of the activity of a cytoplasmic maturation-promoting factor (MPF) was examined. The mouse MPF activity was determined based on its ability to induce maturation in immature starfish oocytes after microinjection with the cytoplasm from mouse oocytes. MPF appeared initially at germinal vesicle breakdown (GVBD), and its activity fluctuated in exact correspondence with meiotic cycles, reaching a peak at each metaphase and almost disappearing at the time of emission of the first polar body. Cycloheximide affected neither the initial MPF appearance nor GVBD. Thereafter, however, in the presence of cycloheximide the meiotic spindle was not formed and MPF disappeared, although the chromosomes remained condensed. After removing cycloheximide, MPF reappeared and was followed by the first metaphase and subsequently by polar body emission. Finally the meiotic cycle progressed to the second metaphase. Thus, for the appearance of MPF, there is a critical period shortly before the first metaphase, after which protein synthesis is required. In the presence of either cytochalasin D or colcemid, MPF activity remained at elevated levels. Addition of cycloheximide to such cytochalasin-treated oocytes, in which the meiotic cycle was arrested at the first metaphase, caused the MPF levels to decrease and was followed by movement of chromosomes to both poles where they decondensed and two nucleus-like structures were formed. Thus, the disappearance of MPF may initiate the metaphase-anaphase transition. Furthermore, detailed cytological examination revealed that chromosomes in cytochalasin-treated oocytes were monovalent while those treated only with cycloheximide were divalent, suggesting that dissociation of the synapsis is a prerequisite for chromosome decondensation after the disappearance of MPF. In all these respects, MPF seems to be a metaphase-promoting factor rather than just a maturation-promoting factor.

Animals↗
PubMed1988

First-phase insulin response to glucose in nonobese or obese subjects with glucose intolerance: analysis by C-peptide secretion rate.

This study was proposed to clarify the impairment of first-phase insulin response to glucose in subjects with glucose intolerance by analysis of C-peptide secretion rate after glucose or glucagon injection. The rate was calculated from kinetic analysis of peripheral C-peptide behavior. The rate reached the peak two minutes after glucose injection and then rapidly declined (first-phase secretion) in control subjects. In nonobese subjects with impaired glucose tolerance (IGT) or non-insulin-dependent diabetes mellitus (NIDDM), the rate promptly increased in response to glucose and was followed by a second phase increase. The time course of the rate in the subjects was slightly different from that in control subjects. There was a progressively greater deficit in the first-phase increase with increasing severity of glucose intolerance. The time course of the rate in the obese subjects with NIDDM was different from that in control subjects. The first-phase increase was reduced in the obese subjects with NIDDM. The glucose disappearance rate was correlated with the first-phase increase. Since the time course of the rate after glucagon injection in all subjects did correspond well with that in the control subjects, variation of metabolic clearance rate of endogenous C-peptide among the subjects may be negligible for this study. This study provides the precise time course of first- and second-phase insulin response to glucose injection in nonobese and obese subjects with IGT or NIDDM as well as convincing evidence of the progressive reduction of first-phase insulin response with increasing severity of glucose intolerance. First-phase insulin response to glucose might be slightly delayed in some obese subjects with NIDDM.

Adult↗
PubMed1988

Synaptic bases of cortically-induced rhythmical hypoglossal motoneuronal activity in the cat.

Intracellular recordings were made from hypoglossal motoneurons during cortically-induced fictive mastication in paralyzed encéphale isolé cats. Repetitive stimulation of the masticatory area of the cerebral cortex induced rhythmical tongue movements coordinated with jaw movements. After the animal was immobilized, the cortical stimulation still induced rhythmical burst activity in the hypoglossal nerve and the digastric nerve. The burst activities in the medial and lateral branches of the hypoglossal nerve alternated rhythmically, and were in and out of phase with the burst activities of the digastric nerve, respectively. All hypoglossal motoneurons showed rhythmical intracellular potentials during repetitive cortical stimulation. The rhythmical depolarizing potentials superimposed by spike bursts appeared in phase with rhythmical bursts in either the lateral or medial branch of the hypoglossal nerve. No hyperpolarization was present between consecutive depolarizing potentials. Synaptic activation noise increased coincidentally with the depolarizing potential, indicating that EPSPs were involved in the generation of the depolarizing potential. No evidence was obtained for the existence of IPSPs during the inter-depolarizing phase by intracellular current injection. It was concluded that rhythmical bombardment of excitatory impulses to hypoglossal motoneurons was responsible for the rhythmical activity induced by repetitive stimulation of the cortical masticatory area.

Animals↗
PubMed1988

Epimerization kinetics of moxalactam in frozen solution.

The epimerization rate constants of R- and S-epimers of moxalactam (LMOX) in a frozen aqueous solution decreased as the temperature decreased. The reaction proceeded in the unfrozen region remaining in the frozen solution, without being affected by the ice. The reaction stopped completely below the collapse temperature of the LMOX aqueous solution. The ratio of R- and S-epimers at equilibrium, which was equal to the ratio of the epimerization rate constant, increased as the temperature decreased. This change in the ratio at equilibrium could be ascribed to the difference in the activation energy between the two epimers.

Chromatography, High Pressure Liquid↗
PubMed1988

Immunotyping of Chlamydia psittaci by indirect immunofluorescence antibody test with monoclonal antibodies.

Monoclonal antibodies against pigeon and budgerigar strains of Chlamydia psittaci were used to classify the immunotypes of C. psittaci strains by an indirect immunofluorescence antibody (IFA) test. Thirty-three C. psittaci strains from pigeons and 24 from budgerigars were divided into three immunotypes (P-I, P-II, and P-III) and (B-I, B-II, and B-III), respectively. Two strains from human psittacosis patients were identified as P-III and B-I, coinciding with the epidemiological evidence of each human infection. Two strains from psittacine birds, a parrot and a parakeet, were identical to the B-II immunotype. Other mammalian strains were quite distinct from avian strains in their IFA reaction with the monoclonal antibodies.

Animals↗
PubMed1988

Enhanced neutralization of flavivirus by monoclonal antibodies against Negishi virus.

Ten monoclonal antibodies against Negishi virus were classified into 3 groups and 7 types according to the reaction patterns to Negishi virus by the hemagglutination inhibition (HI) test and by several kinds of neutralization tests. When kinetic neutralization was applied to these monoclonal antibodies at the same HI titer of 1:64, the initial slope and the persistent fraction of the kinetic curve was varied in each antibody. In the double-kinetic neutralization test, neutralization did not proceed further when the second antibody was the same type as the first one. When the second antibody was a different type from that of the first one, neutralization proceeded further. The mixtures of 4 monoclonal antibodies classified as different groups and types remarkably enhanced neutralization in the kinetic assay. These results suggested that an assortment of antibodies is needed for effective neutralization of Negishi virus and that a multi-hit model is likely operating in the neutralization of Negishi virus.

Animals↗
PubMed1988

Gingival pigmentation beneath a metallic crown: light and electron microscopic observations and energy dispersive X-ray analysis.

Light and electron microscopic studies and energy dispersive X-ray analysis disclosed that the essential cause of gingival discoloration following the placement of a metallic crown, was marked deposition of melanin pigment. Deposition of melanin pigment was observed in epithelial cells, on basement membranes, and in fibroblasts, macrophages and among intercellular ground substance of the proprial layer. Brown or dark brown colored granules were observed in the deep portion of the proprial layer. Some metallic elements as silver and sulfur were detected. It was presumed that these materials were dental metals accidentally implanted in gingival tissues during the therapeutic procedure. The deposition of melanin pigment closely corresponded with mucosal tissue where these materials were present in the deep portion of the proprial layer. These findings suggested that these materials influenced the physiological metabolism of melanin and induced its pathological deposition in the proprial tissue.

Adult↗
PubMed1988

Involvement of internal elastic lamina in development of induced cerebral aneurysms in rats.

To elucidate the role of the internal elastic lamina in the development of cerebral aneurysm, the bifurcation of the anterior cerebral artery and olfactory artery was histologically studied in control and experimental rats treated with unilateral carotid ligation and renal hypertension. Various stages of aneurysm formation were compared, and it was found that early aneurysmal changes were always present just distal to the apical intimal pad on the anterior cerebral artery side. The internal elastic lamina was thinned and fragmented just distal to the pad even in the very early stage of aneurysm formation when the medial layer was still present. In control rats, the internal elastic lamina had a tendency to thin and fragment at the site where aneurysms would develop in experimental rats. Our study shows that changes of the internal elastic lamina were present just distal to the pad even in control rats, which never develop cerebral aneurysms. Under hemodynamic stress augmented by experimental treatments, further degenerative changes of the internal elastic lamina and involvement of the medial layer are considered to occur and result in aneurysm formation there.

Animals↗
PubMed1988

A case of hypopituitarism due to granulomatous and lymphocytic adenohypophysitis with minimal pituitary enlargement: a possible variant of lymphocytic adenohypophysitis.

A 47-year-old woman complaining of cold intolerance, general weakness and amenorrhea of 10 months duration was diagnosed, by endocrine examinations, as having panhypopituitarism. Skull x-ray films revealed a slightly enlarged sella with double floor sign and MRI showed a low intensity mass in the pituitary. Transsphenoidal exploration disclosed a degenerated pituitary gland, the histology of which showed a granulomatous lesion with moderate lymphocytic infiltration but containing no multinuclear giant cells. No caseous necrosis, causative microorganisms, or BCG antigen were noted. The present case is considered a variant form of lymphocytic adenohypophysitis.

Female↗
PubMed1988

Type IV collagen-degrading enzyme activity in human serum.

Type IV collagen-degrading enzyme activity was detected in human serum. Serum was preincubated with 4-aminophenylmercuric acetate and trypsin to activate the enzyme prior to assay. Type IV collagen, purified from human placentas and radiolabeled with [1-14C] acetic anhydride, was used as the substrate. The enzyme activity was measured at pH 7.5 and inhibited by treatment with ethylenediaminetetraacetic acid or heat. The assay of type IV collagen-degrading enzyme in human serum might be useful for estimating the degradation of type IV collagen.

Blood Proteins↗
PubMed1988

Serum type IV collagen-degrading enzyme in hepatocellular carcinoma with metastasis.

The activity of serum type IV collagen-degrading enzyme was measured in 18 patients with hepatocellular carcinoma (HCC). The enzyme activity was significantly higher, in HCC patients with a tumor thrombus in the portal vein than in healthy controls, liver cirrhosis patients and HCC patients without a tumor thrombus. Moreover, the activity in HCC patients with lung metastasis tended to be higher than that in HCC patients without lung metastasis. The activity of serum type IV collagen-degrading enzyme did not correlate with tumor size, serum alpha-fetoprotein level, or macroscopic classification of tumor growth. These results suggest that the activity of serum type IV collagen-degrading enzyme represents the metastatic potential or the ongoing metastatic activity of HCC. The enzyme is a useful serum marker of metastasis from HCC.

Aged↗
PubMed1988

Ecological studies of Japanese encephalitis virus in Hokkaido: interepidemic outbreaks of swine abortion and evidence for the virus to overwinter locally.

Outbreaks of abortion and stillbirth caused by Japanese encephalitis virus were observed in swine populations in Hokkaido in 1984 and 1985. Two strains of Japanese encephalitis virus were isolated from aborted fetuses in different outbreaks, and the antigenic types of the strains found to be different from Nakayama and JaGAr-01. The outbreak of 1985 was in early June, the interepidemic period of Japanese encephalitis in northern temperate zones. A seroepidemiological survey carried out from 1984 to 1986 in 14 districts showed high rates of Japanese encephalitis antibody in swine sera in two districts. A more detailed 3-year survey showed that pig farms positive for Japanese encephalitis antibody were detected at the same sites in Hiroshima near Sapporo as negative farms. These data suggest that Japanese encephalitis virus is maintained in a distinct endemic focus and has the capacity to overwinter locally in Hokkaido.

Abortion, Veterinary↗