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Biomedical subjects

K Imamura

Publications and source records attributed to K Imamura.

At least 145 records · Page 8Linked to original sources
PubMed1994

Induction of MHC class II antigen expression on murine microglia by interleukin-3.

The effects of various cytokines on MHC class II antigen expression were examined in murine microglia. Interleukin-3 (IL-3), as well as interferon-gamma (IFN-gamma), induced MHC class II antigen expression on these cells. IL-3 additionally enhanced MHC class II antigen expression induced by IFN-gamma. The induction of MHC class II antigen expression by IL-3 was not mediated via IFN-gamma production, because the effect was not blocked by antibodies to IFN-gamma. In contrast, granulocyte-macrophage colony-stimulating factor (GM-CSF) did not affect the expression of MHC class II antigen on naive cells and down-regulated IFN-gamma-mediated induction of MHC class II antigen expression on microglia. Because IL-3 and GM-CSF are apparently produced in the central nervous system, MHC class II antigen expression on microglia may be regulated by these cytokines synthesized in the central nervous system.

Animals↗
PubMed1994

Characterization of ascorbate oxidase from Acremonium sp. HI-25.

The ascorbate oxidase obtained from a microorganism, Acremonium sp. HI-25 (molecular weight, 80 kDa; monomeric protein), was studied with respect to atomic absorption, EPR, absorption spectra, circular dichroism (CD) spectra, and steady-state kinetics. The enzyme was found to be a multicopper protein, containing four copper atoms of three kinds, types 1, 2, and 3 copper, in the ratio of 1:1:2. The EPR parameters of the type 1 and 2 copper atoms in the ascorbate oxidase are very similar to those in the case of the ascorbate oxidase obtained from cucumber, which is a dimeric protein. The apparent Km and kcat values for ascorbic acid of the ascorbate oxidase from Acremonium sp. HI-25 are almost the same as those of the monomeric unit of the ascorbate oxidase from cucumber.

Acremonium↗
PubMed1994

Reproducibility of magnetic resonance spectroscopy in patients undergoing dialysis and evaluation of the therapeutic response of tumors.

RATIONALE AND OBJECTIVES: The reproducibility of repeated magnetic resonance (MR) spectroscopy was studied in patients undergoing dialysis and treatment of a variety of malignant tumors. METHODS: Localized MR spectra were obtained using a 1.5-T system by image-selected in vivo spectroscopy. Total metabolite signal was integrated between phosphomonoester and beta-adenosine triphosphate resonance. We termed this measurement AREA. RESULTS: Intrapatient variability was evaluated on repeated thigh muscle spectroscopy for 10 patients. Sequential spectra of 10 malignant tumors of the extremities were analyzed and compared with the histology of surgical specimens in seven patients. Intrapatient variability in AREA was calculated as 14.0%. The extent of necrosis and AREA ratio (definition: AREA post-therapy/AREA pretherapy) were as follows; 6.1% in > 90% necrosis, 43% in 50% to 90% necrosis, and 79% in < 50% necrosis. CONCLUSIONS: Localized MR spectra are fairly reproducible and may relate to treatment efficacy.

Adolescent↗
PubMed1994

Correlation between bile acid malabsorption and pancreatic exocrine dysfunction in patients with chronic pancreatitis.

Fecal bile acid and fecal fat were determined in 18 normal subjects and 22 patients with chronic pancreatitis, and the relation of fecal bile acid excretion to exocrine pancreatic dysfunction was studied. In chronic pancreatitis fecal bile acid was approximately three times that of control subjects, and large amounts of primary bile acid were detected. A significant correlation between fecal bile acid excretion and bicarbonate secreted from the pancreas was found. This evidence of bile acid malabsorption was not observed until bicarbonate output was < 0.05 mEq/h/kg. A slight correlation between fecal bile acid and absorption rates of fat was demonstrated. These results suggest that bile acid malabsorption observed in chronic pancreatitis is related to an impairment of pancreatic bicarbonate secretion.

Adult↗
PubMed1994

Epidemiologic analysis of spatial clustering of bovine ephemeral fever outbreaks. II. Principal component analysis.

The principal component analysis (PCA) was applied to analyze a correlation matrix of three variables on epidemic data of bovine ephemeral fever (BEF) outbreaks. These original data were summarized from the official outbreak report of Fukuoka Prefecture. The first and the second principal components of the PCA were interpreted as the infectious potency due to BEF virus and the prevention against BEF virus infection, respectively. The BEF outbreak areas were able to be classified epidemically into 4 groups by using the two principal components. The valuable epidemiological insights can be reasonably obtained from an application of the PCA. The results provided an important information for a further BEF vaccination campaign in the western part of Japan.

Animals↗
PubMed1994

Development of early-stage embryos of the Japanese field vole, Microtus montebelli, in vivo and in vitro.

Although ovulation could be easily induced in the Japanese field vole by administering pregnant mares' serum gonadotrophin and hCG, the number of embryos obtained varied from 1 to 47 (mean, 9.6). One-cell embryos were small (57.8-63.3 microns in diameter; mean, 61.0 microns) compared with those in other mammals. Development of the preimplantation vole embryos in vivo was similar to that of mouse embryos. The first cleavage occurred between 24 and 26 h after mating. The second cleavage was between 46 and 52 h after mating, and subsequent cleavages occurred at about 12 h intervals. Blastocysts were clearly observed in the uterus 4 days after mating. Vole embryos could be cultured in vitro from the late two-cell to the blastocyst stage in M16 medium. However, development of one-cell and early two-cell embryos in vitro was limited, and few cleaved beyond the four-cell stage. Eliminating sodium pyruvate from M16 medium significantly improved the development of early two-cell embryos into blastocysts (P < 0.05). The Japanese field vole may be a useful experimental animal for reproductive biology, comparable with the mouse.

Animals↗
PubMed1994

Decreased gastric secretory functions in diabetic patients with autonomic neuropathy.

A total of 37 subjects consisted of 10 healthy subjects (Group III), 15 diabetic patients without autonomic neuropathy (Group II), and 12 diabetic patients with autonomic neuropathy including gastroparesis in 6 cases (Group I). All three groups were comparable in age. In order to clarify the gastric function in diabetic patients with autonomic neuropathy, secretion of serum gastrin, gastric secretory function, endoscopic Congo red test of fundic glands, and coefficiency of variance of electrocardiographic beat-to-beat intervals (C.V. R-R) were examined. In Group I, 5 patients had hypergastrinemia, but its elevation was inhibited when an acid solution was injected into the stomach. Gastric secretion and C.V. R-R were markedly lower in Group I, compared with Groups II and III. In Group I, the area of fundic glands (parietal cells) was reduced considerably. The C.V. R-R was significantly correlated with fasting serum gastrin concentration and with maximal acid output. From these results, in diabetic patients with autonomic neuropathy (vagal neuropathy), gastric acid secretion in response to tetragastrin stimulation was lowered with a reduction in area of fundic gland distribution. Hypergastrinemia may reflect a negative feedback mechanism responding to decreased acidity of gastric content in the antrum.

Adult↗
PubMed1994

Increased plasma gluconeogenic and system A amino acids in patients with pancreatic diabetes due to chronic pancreatitis in comparison with primary diabetes.

We examined the plasma amino acid profiles of 17 patients with pancreatic diabetes in comparison with those of 14 healthy subjects and 16 patients with primary diabetes of similarly poor glycemic control. We also measured fasting plasma glucagon and free insulin levels in patients with pancreatic diabetes and in those with primary diabetes. The fasting plasma amino acid level was highest in patients with pancreatic diabetes. Furthermore, the plasma glucagon level in patients with pancreatic diabetes was significantly low, and negative correlations were found between glucagon and glucagon-related System A and gluconeogenic amino acids. On the other hand, the levels of branched-chain amino acids (BCAA) and System L amino acids, which are subjected to change in the state of diabetes mellitus, increased in patients with pancreatic diabetes. From the above results, we determined that the amino acid profile in patients with pancreatic diabetes resembled that in patients with total pancreatectomy. It is our opinion that the increases of amino acid levels (gluconeogenic and System A amino acids) in patients with pancreatic diabetes is not dependent on maldigestion/malabsorption under treatment, but is mainly dependent on glucagon deficiency.

Amino Acids↗
PubMed1994

Decreased counterregulatory hormone responses to insulin-induced hypoglycemia in patients with pancreatic diabetes having autonomic neuropathy.

Thirteen patients with pancreatic diabetes caused by calcifying pancreatitis were divided into 2 groups; 5 with diabetic autonomic neuropathy [AN(+) group] and 8 without [AN(-) group]. They were subjected to an insulin-induced hypoglycemic stress test to evaluate their blood pancreatic glucagon, adrenalin, and cortisol responses. When a blood glucose level below 45 mg/100 ml was defined to be hypoglycemia, all the patients in the AN(-) group exhibited peripheral adrenalin responses, with a significant increase (mean, 19.0 times the basal level) in the blood adrenalin level. Among the AN(+) group, on the other hand, central nervous symptoms became evident rather than the peripheral adrenalin response (the blood adrenalin level hardly exceeded the basal level). With the exception of a single patient, none exhibited responses in the blood pancreatic glucagon levels. Only one patient showed a minimal cortisol response but the remaining 12 reacted normally in the cortisol release. The findings are summarized as follows: in pancreatic diabetes, insulin-induced hypoglycemia causes little change in pancreatic glucagon secretion; when the condition is complicated with autonomic neuropathy, central nervous symptoms develop while the blood adrenalin level hardly increases. These findings indicated that patients with pancreatic diabetes complicated with diabetic autonomic neuropathy have a risk of lapsing into an acute hypoglycemic coma and difficulty in recovering from the hypoglycemic state.

Alcoholism↗
PubMed1994

Diabetic retinopathy in Japanese patients with long-standing pancreatic diabetes due to calcifying pancreatitis.

This study analyzed the prevalence, aggravating factors (including duration of diabetes, glycemic control, body mass index, hypertension, serum total cholesterol, changes of ST on ECG and diabetic therapies) and characteristics of diabetic retinopathy in 75 patients with pancreatic diabetes resulting from calcifying pancreatitis. The patients were divided into three Groups: Group I (27 patients in whom diabetes was detected earlier than pancreatic stones), Group II (36 patients in whom diabetes and pancreatic stones were simultaneously detected) and Group III (12 patients in whom pancreatic stones were detected earlier than diabetes). The prevalence of retinopathy was dependent on the duration of diabetes as well as poor glycemic control. It was significantly (p < 0.01) higher among the patient with the duration of diabetes that was more than 5 years than that of the patients whose duration was less than 5 years. The prevalence of retinopathy in Group I (63%) was significantly (p < 0.05) higher than that in Group II (30.6%) and Group III (12.5%). Proliferative retinopathy was not found in any patients with a duration of diabetes less than 5 years, while it was found in 5 patients with a duration of more than 5 years (5 cases out of 31 patients). Diabetic retinopathy was correlated with the duration of diabetes and glycemic control, and was not linked to frequency of hypoglycemia and family history of diabetes. From the results above, we concluded that diabetic retinopathy in patients with pancreatic diabetes due to calcifying pancreatitis might be taken as evidence that such complications are primarily due to chronic hyperglycemia and the duration of diabetes mellitus rather than to genetic factors and other factors (body mass index, hypertension, serum total cholesterol and diabetic therapies).

Adult↗
PubMed1994

Octreotide decreases biliary and pancreatic exocrine function, and induces steatorrhea in healthy subjects.

A somatostatin analogue (SMS-201-995, hereinafter "octreotide") was s.c. administered to 5 healthy subjects under consecutive dripping of CCK-PZ (cholecystokinin-pancreozymin) and secretin (0.01 CHR U/kg/minutes), after inserting a Dreiling double tube into Treitz's ligament. Bile acid concentration, and bicarbonate and lipase excretions in duodenal juice were determined every 10 minutes up to 120 minutes and compared with controls. Moreover, octreotide (100 micrograms) was s.c. administered to 5 healthy subjects 30 minutes before meals for 7 days. Fecal fat and bile acid excretions before and after administration were determined. Bile acid concentration, and bicarbonate and lipase excretions in the octreotide group decreased to 1/3-1/4 that of controls. Bile acid concentration became 0 mM for 60 minutes. Fecal fat excretion increased; obvious steatorrhea occurred in 2 cases. Fecal bile acid excretion decreased to about 1/4. These results suggest that decreases in bile acid secretion should be considered, as well as pancreatic lipase and bicarbonate secretions, when fatty stool occurs after octreotide administration.

Adult↗
PubMed1994

The role of the autonomic nervous system in the thermic effects of protein and carbohydrates in rats.

To investigate the roles of the autonomic nervous system in the thermic effects of protein and carbohydrates in rats, we determined the urinary excretion of catecholamines and the resting oxygen consumption by means of HPLC-fluorometry and open-circuit respirometry, respectively. Protein administration significantly increased the urinary excretion of norepinephrine and epinephrine over those on water administration. The thermic effect of protein was 16.6% of the basal metabolic rate and was inhibited by phentolamine, prazosin, or atropine, but not by propranolol. These results suggest that the sympathetic nervous system via alpha 1-adrenoceptors and the parasympathetic nervous system are involved in the thermic effect of protein. The administration of carbohydrates such as glucose, sucrose, and fructose significantly enhanced the urinary excretion of norepinephrine, but only glucose administration increased the urinary excretion of epinephrine. The thermic effects of carbohydrates were 8-9% of the basal metabolic rate and were inhibited by propranolol, but not by phentolamine or atropine. These findings suggest that the sympathetic nervous system via beta-adrenoceptors, but not the parasympathetic nervous system, contributes to the thermic effect of carbohydrates. Thus, we conclude that the autonomic nervous system is involved in the thermic effects of protein and carbohydrates by different mechanisms.

Animals↗
PubMed1994

PF1018, a novel insecticidal compound produced by Humicola sp.

A new insecticidal compound PF1018 was isolated from the culture broth of Humicola sp. It exhibited insecticidal activity against a wide range of critical pest species. The structure of PF1018 was determined to be (7aS)-2-((2E)-1-hydroxy-3-((1S,3aR,4R,5R,7aR)-3a,4,5,7 a-tetrahydro-1,3,5,7- tetramethyl-5,1-((3S)-(Z)-2,3-dimethylpropeno)-1H-inden-4-yl )-2- propenylidene)pyrrolizidine-1,3-dione, by NMR spectral analyses coupled with X-ray crystallographic analysis and chemical degradation study.

Chromatography, High Pressure Liquid↗
PubMed1994

[Clinical efficacy of sairei-to in various urinary tract diseases centering on fibrosis].

A joint multi-institution study was conducted on the efficacy of Sairei-to, centering on urinary tract fibrosis. The subjects consisted of 18 patients with retroperitoneal fibrosis (including 3 women), 77 patients with plastic induration of penis, 5 patients with sclerotic lipogranuloma (all men), and 67 patients with hemorrhagic cystitis (including 6 men). As a rule, Sairei-to was administered in monotherapy for periods of 4 weeks or longer. Efficacy was most pronounced in the patients with sclerotic lipogranuloma and plastic induration of penis, with overall improvement rates (percentage of patients with ratings of effective or better) of 80% in the former and 77.9% in the latter group. The overall improvement rate in the patients with retroperitoneal fibrosis was 61.1%. In the above diseases, there were numerous patients concurrently administered drugs such as antiinflammatory enzyme preparations and corticoid preparations, and the improvement rates were somewhat higher in these patients treated concurrently with other drugs. Outstanding efficacy was also seen in hemorrhagic cystitis. Dividing the patients into irradiation and non-irradiation groups, respective overall improvement rates of 77.8% and 82.8% were obtained, with the non-irradiation group showing a slightly higher rate. The non-irradiation group showed slightly higher improvement rates in the subjects treated concurrently with drugs such as antibacterial drug. Conversely, the irradiation group showed significantly superior rates for monotherapy. Side effects such as mild gastrointestinal disturbances were seen in only 13 of 167 patients (7.8%), and the utility of this drug in treatment of the above diseases should be held in high regard.

Adult↗