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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 433 records · Page 24Linked to original sources
PubMed1994

Geographic distribution of Gongylonema pulchrum and Gongylonema macrogubernaculum from Macaca fuscata in Japan.

After a first report on the gullet nematode, Gongylonema pulchrum Molin, 1857, being found in the Japanese macaque, Macaca fuscata, in Kyushu, Japan, the geographic distribution of the parasite, a causative agent of gongylonemiasis in cattle and man, was examined in 181 monkeys transferred to the Japan. Monkey Centre from 23 sites in Japan, including Yaku-shima (Island). Yaku-shima is included in the World Natural Heritage List of the United Nations for its subtropical forests, which have an unusual variety of plant and animal species. G. pulchrum was found in M. fuscata yakui monkeys inhabiting Yaku-shima and M. fuscata fuscata monkeys inhabiting Honshu and an is and near Honshu. G. macrogubernaculum was found in M. fuscata yakui monkeys. Comparison of the two kinds of parasite specimens obtained from the variety M. fuscata yakui confirmed that G. macrogubernaculum Lubimov, 1931 is a valid species. Thus, the finding of G. macrogubernaculum constitutes a record of a newly identified host. M. fuscata yakui, and shows that Yaku-shima, Japan, is a natural locality of G. macrogubernaculum.

Animals↗
PubMed1994

Hypoglycemic action of the rhizomes of Polygonatum officinale in normal and diabetic mice.

The hypoglycemic effect of the rhizomes of Polygonatum officinale (Liliaceae) was investigated in both normal and streptozotocin-induced diabetic mice. The methanol extract of rhizomes of Polygonatum officinale (PO) (800 mg/kg) reduced the blood glucose of normal mice from 170 +/- 3 to 136 +/- 5 mg/100 ml 4 hours after intraperitoneal administration (P < 0.001), and also significantly lowered the blood glucose of streptozotocin-induced diabetic mice from 696 +/- 60 to 407 +/- 35 mg/100 ml under similar conditions (P < 0.01). PO also suppressed epinephrine-induced hyperglycemia in mice. In addition, the n-butanol fraction of the methanol extract elicited a significant decrease in the blood glucose level of streptozotocin-induced diabetic mice after 4 hours (P < 0.05).

Animals↗
PubMed1994

Evolution of the replication regions of IncI alpha and IncFII plasmids by exchanging their replication control systems.

The basic replicons of bacterial plasmids consist of two sets of genetic systems, the replication-structural system and the replication control system. Comparison of nucleotide sequences suggested that the basic replicons of plasmids P307 (IncFI) and pMU2200 (IncZ) were generated by reciprocal recombination between ancestors of R100 (IncFII) and ColIb-P9 (IncI alpha), or vice versa. The plasmids of each pair, P307/pMU2200 and R100/ColIb-P9, are structurally unrelated to each other. Based on this information, we constructed in vitro and analyzed P307-like chimeric replicons from ColIb-P9 and R100. When the replication-structural region of ColIb-P9 was combined with the whole replication control region of R100, the resultant replicon replicated stably as R100 did. These results revealed that the basic replicons of the plasmids diverged by exchanging their replication control systems. Thus, we propose that the replication control systems of plasmids, in some cases, evolved independently of their structural systems, although these two systems work together to maintain the replication functions. We also showed that the reciprocal recombination was specified by the unique secondary structures of RNA involved in the control of expression of the genes encoding the replication initiator proteins.

Amino Acid Sequence↗
PubMed1994

Regulation of the Escherichia coli hfq gene encoding the host factor for phage Q beta.

The host factor (HF-I) for phage Q beta RNA replication is a small protein of 102 amino acid residues encoded by the hfq gene at 94.8 min on the Escherichia coli chromosome. The synthesis rate of HF-I at the exponential-growth phase is higher than at the stationary phase, and it increases concomitantly with the increase in cell growth rate. The intracellular level of HF-I is about 30,000 to 60,000 molecules per cell, the majority being associated with ribosomes as one of the salt wash proteins. Taken together, we suggest that HF-I is one of the growth-related proteins.

Allolevivirus↗
PubMed1994

Mechanisms for protective effects of free radical scavengers on gentamicin-mediated nephropathy in rats.

Studies were performed to examine the mechanisms for the protective effects of free radical scavengers on gentamicin (GM)-mediated nephropathy. Administration of GM at 40 mg/kg sc for 13 days to rats induced a significant reduction in renal blood flow (RBF) and inulin clearance (CIn) as well as marked tubular damage. A significant reduction in urinary guanosine 3',5'-cyclic monophosphate (cGMP) excretion and a significant increase in renal cortical renin and endothelin-1 contents were also observed in GM-mediated nephropathy. Superoxide dismutase (SOD) or dimethylthiourea (DMTU) significantly lessened the GM-induced decrement in CIn. The SOD-induced increase in glomerular filtration rate was associated with a marked improvement in RBF, an increase in urinary cGMP excretion, and a decrease in renal renin and endothelin-1 content. SOD did not attenuate the tubular damage. In contrast, DMTU significantly reduced the tubular damage and lipid peroxidation, but it did not affect renal hemodynamics and vasoactive substances. Neither SOD nor DMTU affected the renal cortical GM content in GM-treated rats. These results suggest that 1) both SOD and DMTU have protective effects on GM-mediated nephropathy, 2) the mechanisms for the protective effects differ for SOD and DMTU, and 3) superoxide anions play a critical role in GM-induced renal vasoconstriction.

Acetylglucosaminidase↗
PubMed1994

Acute estradiol modulation of electrical activity of the LHRH pulse generator in the ovariectomized rat: restoration by naloxone.

Whether estrogen has the brain as a site of its negative feedback action was investigated by checking the acute effect of estradiol-17 beta (E2) on the electrical activity of the luteinizing hormone-releasing hormone (LHRH) pulse generator in ovariectomized rats fitted with chronically implanted electrode arrays in the medial basal hypothalamus. Before subcutaneous E2 implantation, the hypothalamic multiunit activity (MUA) exhibited, at an average frequency of 2.43/h, characteristic increases (volleys), each of which was associated with the initiation of an LH pulse. Within 2 h after E2 implantation, the frequency of MUA volleys was reduced significantly, probably associated with decreases in the frequency of LH pulses. The decrease in the amplitude of LH pulses occurred later than 2 h, but this effect was considered not to be mediated by the brain since the duration of MUA volleys was not changed. Since the mean serum LH concentration started to decrease within 2 h after E2 implantation, it was concluded that the acute inhibitory E2 effect on LH release is mediated by the brain. On the day after E2 implantation, intravenous infusion of naloxone (2 mg/kg/h) promptly elicited intermittent MUA volleys each of which was associated with an LH pulse. This suggests that operation of the LHRH pulse generator in the ovariectomized condition is restrained by the action of E2 with the mediation of endogenous opioid peptide neurons.

Animals↗
PubMed1994

Isolation and serological characterization of porcine reproductive and respiratory syndrome (PRRS) viruses from pigs with reproductive and respiratory disorders in Japan.

Three porcine reproductive and respiratory syndrome viruses (PRRSVs) were successfully isolated from stillborn piglets and fattening pigs derived from different herds affected either with an epizootic reproductive failure or a severe chronic respiratory distress in Japan. The isolates were reacted with antisera against both European (Lelystad virus) and American (strain 46448) PRRSVs in indirect immunofluorescence (IIF). However, cross immunoperoxidase monolayer assay revealed the close serological relationships between the Japanese isolates and American PRRSV, but not between the Japanese isolates and the European PRRSV. The data of preliminary serological survey with IIF technique showed a high frequency of antibody positive pigs against both Japanese isolate and the American PRRSV, whereas a low frequency of antibody positive pigs against the European PRRSV, on herds which have had clinical episodes of PRRS-like diseases. These results indicate that PRRSVs are prevalent in Japan, and suggest that the antigenicities of the prevalent PRRSVs are more closely related to those of the American than the European PRRSVs.

Animals↗
PubMed1994

An outbreak of porcine reproductive and respiratory syndrome in Japan.

An emerging swine disease principally involving periweaning piglets was examined. The disease was clinically characterized by lethargy, fever, emaciation, coughing, and severe abdominal breathing, hence colloquially named "Heko-heko" disease. The consistent lesions in affected piglets were diffuse interstitial pneumonia with pronounced type II pneumocytic proliferation, meningoencephalitis, and regression of the lymphoid tissues. The causal virus was isolated in primary porcine lung cell (PLC) cultures from various organs of affected piglets and showed serological relatedness to the European porcine reproductive and respiratory syndrome (PRRS) virus. Numerous virus particles, measured about 49 nm in diameter, were detected in the cytoplasm of alveolar epithelial cells and pulmonary macrophages in PLC cultures infected with the isolate. The condition could be experimentally reproduced in conventional piglets by intranasal inoculation with the isolate and the virus was reisolated from the infected animals.

Animals↗
PubMed1994

Suppressive effects of polygonati rhizoma on hepatic glucose output, GLUT2 mRNA expression and its protein content in rat liver.

The intraperitoneal administration of the methanol extract of Polygonati Rhizoma (OM) into normal rats caused a significant decrease in the blood glucose level at 4 h after its administration of 800 mg/kg (P < 0.01), but not the serum insulin level. Using the perfused rat liver in vitro, a significant decrease of the hepatic glucose output was observed by the infusion of OM (P < 0.05 at 250 micrograms/ml OM). In addition, the hepatic content of facilitative glucose transporter isoform 2 (GLUT2) mRNA and its protein content in the total membrane fraction from rat liver significantly decreased in the intraperitoneally OM-treated rats when compared to that in the controls (mRNA P < 0.01, protein P < 0.001). On the other hand, OM (500 micrograms/ml) exhibited no apparent stimulatory effect on the insulin secretion from the isolated rat pancreatic islets. These results suggest that the hypoglycemic effect of OM is derived, at least in part, from the decrease in hepatic glucose output, due presumably to the reduction of GLUT2 mRNA expression and its protein content in total membrane of the liver, and that because of its unique therapeutic mechanism, OM could be a new category of therapeutic agent for non-insulin-dependent diabetes mellitus.

Animals↗
PubMed1994

Mouse Ly-gene haplotypes and subcutaneous regression of Ehrlich ascites tumor.

Ehrlich ascites tumor cells (EAT cells) lack most cell surface H-2 antigens and grow in any mouse strain following intraperitoneal injection of 10(5) cells. With subcutaneous injection of 2 x 10(7) cells, however, EAT regressed in C57BL/10 (H-2b), BALB/c (H-2d), NZB (H-2d), A (H-2a) and SJL (H-2s) but progressed and formed a solid tumor in DBA/2 (H-2d), C3H (H-2k), AKR (H-2k), CBA (H-2k) and DBA/1 (H-2q). By genotype analysis, Ly haplotypes of EAT-regressive mouse strains were found to have Ly-1.2 and Ly-2.2 as common features, while EAT-progressive mouse strains had Ly-1.1 (except AKR) and Ly-2.1.

Animals↗
PubMed1994

Nephrogenic diabetes insipidus associated with bilateral ureteral obstruction.

Nephrogenic diabetes insipidus associated with ureteral obstruction is rare. We report a case of nephrogenic diabetes insipidus associated with ureteral obstruction caused by ileal leiomyosarcoma in a 32-year-old man. The treatment with trichlorothiazide and diclofenac sodium reduced urine output from 8 L/day to 4 L/day. Six months after nephrostomy, urine output decreased to 2.5 L/day without any drug administration. This case suggests that ureteral obstruction may cause an increase in urine output to 8 L/day and that surgical treatment for ureteral obstruction is effective in reducing urine output in nephrogenic diabetes insipidus patients with ureteral obstruction.

Adult↗
PubMed1994

Roles of hemodynamic and tubular factors in gentamicin-mediated nephropathy.

Gentamicin (GM) often causes polyuric acute renal failure (ARF) in humans and animals. GM-mediated ARF in rats was accompanied with activated renin-angiotensin system, increased renal endothelin content, and enhanced lipid peroxidation. Suppression of the renin-angiotensin activity by desoxycorticosterone acetate and saline drinking, and treatment with superoxide dismutase attenuated the GM-induced decline in whole-kidney GFR with well-maintained RBF but did not reduce the severity of tubular necrosis. On the other hand, treatment with dimethylthiourea, a hydroxyl radical scavenger, attenuated the GM-mediated decline in GFR and lessened tubular necrosis but did not ameliorate the reduction in RBF. These data suggest contributions of both vascular and tubular factors to the GM-induced decline in GFR in rats. However, relative importance of these factors probably differs with different doses of the agent.

Acute Kidney Injury↗
PubMed1994

Erythropoietin production in patients with chronic renal failure.

Studies were performed to reexamine the response of erythropoietin (Epo) production to acute hypoxic stimuli in patients with end-stage renal disease (ESRD). In the absence of acute bleeding or hypoxia, the serum Epo level in ESRD was similar to that of normal subjects despite severe anemia. In 11 dialysis patients with acute bleeding, the decrease in the Hb level from 8.9 to 5.8 g/dL provoked a significant increase in serum Epo up to 52.2 times the normal value. The increase in serum Epo was associated with a significant increase in corrected reticulocyte. Systemic hypoxemia (PaO2 < 65 mm Hg) in 8 dialysis patients provoked a significant elevation in the serum Epo level up to 24.6 times the normal level. There was an inverse relationship between serum Epo and arterial PaO2 (r = -0.715). The serum Epo level in these patients declined to or near the normal value after recovery from acute hypoxic stress. These data suggest that the ability of the Epo production is well preserved in ESRD, indicating that acute hypoxic stimuli provoke a significant increase in serum Epo.

Acute Disease↗
PubMed1994

[A case of dementia associated with multiple iron deposits in the brain on MRI].

We report a 63-year-old man presenting with dementia and cerebellar ataxia associated with multiple iron deposits in the brain on MRI. Numerous small lesions of low-intensity on both T1- and T2-weighted images were found in the parenchyma and surface of the cerebrum, cerebellum and brain stem. The number and size of lesions were increased on MRI with the method of gradient recalled acquisition in the steady state (GRASS), indicating that they were composed of iron. The similar lesions were not found in any organs on the abdominal GRASS-MRI. Any abnormalities were also not found in the cerebral angiography. Meanwhile, the protein and IgG levels and activated CD4-cells were increased in the cerebrospinal fluid, indicating the involvement of chronic inflammation in the iron deposits in this case.

Brain↗
PubMed1994

[Mechanism of ascites formation and its management in liver cirrhosis].

The "underfilling" and "overflow" theories have been proposed as the pathogenesis of ascites formation in patients with liver cirrhosis. The "peripheral arterial vasodilation hypothesis" has been also proposed recently. Essential treatment of ascites are; restriction of physical activity, sodium restriction, supplement of albumin, and diuretic therapy. Alternative therapy for refractory ascites include peritoneal-venous shunt, ascites ultrafiltration and reinfusion and body oppression therapy. Assessment of liver function, renal function and the systemic hemodynamic state as well as characterization of ascitic fluid are also needed to evaluate the effectiveness of the therapy.

Adult↗
PubMed1994

[A case of epileptic laughter associated with temporal epidermoid cyst: surgical treatment combined with subdural grid electrode study].

A case of epileptic laughter associated with deep right temporal epidermoid cyst is reported. Interictal EEG with subdural grid electrodes demonstrated multifocal spike discharges in the right temporal lobe. Ictal EEG localized the epileptogenic foci at the base of the anterior medial temporal lobe. After standard temporal lobectomy, the tumor was completely removed. The patient is free from seizures postoperatively.

Brain Diseases↗