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Biomedical subjects

Y Kitagawa

Publications and source records attributed to Y Kitagawa.

At least 181 records · Page 10Linked to original sources
PubMed1996

Intravenous catecholamines alter hepatic blood flow in conscious dogs with experimental hepatic denervation.

Hepatic blood flow is regulated by the autonomic nervous system; however, blood flow through the denervated liver has been controversial. The purpose of this study is to evaluate the changes in hepatic blood flow caused by experimental hepatic denervation during the intravenous infusions of catecholamines (dopamine or dobutamine) with or without prior administration of alpha-adrenoceptor antagonist (phenoxybenzamine) or beta-adrenoceptor antagonist (propranolol). The liver blood flow was measured using transit time ultrasonic flow meter probes at the portal vein and hepatic artery in conscious dogs which (a) underwent hepatic denervation (denervation group, n = 9) and (b) were intact (control group, n = 10). Norepinephrine concentrations in the liver were determined to evaluate the effects of hepatic denervation and were decreased at 1 week and 4 weeks after hepatic denervation. In the control group, dopamine and dobutamine produced an increase of portal venous blood flow (PVF). Conversely, hepatic denervation reduced the increase in PVF by dopamine and dobutamine. Dopamine with prior administration of phenoxybenzamine produced a much larger increase in PVF in both groups. Pretreatment of propranolol in both groups abolished the increasing effects of dopamine and dobutamine in PVF. Dopamine reduced the hepatic arterial blood flow (HAF) regardless of hepatic denervation. During dobutamine infusion, HAF was decreased by hepatic denervation and prior administration of propranolol. These results suggest that hepatic denervation reduces the increasing effects of catecholamines on the hepatic blood flow through greater enhancement of alpha-adrenergic effects than of beta-adrenergic effects in the hepatic vascular autonomic nerve response.

Animals↗
PubMed1996

The effects of intravenously infused catecholamines on hepatic blood flow in conscious dogs with experimental obstructive jaundice.

This study was conducted to examine how the effects of dopamine and dobutamine on hepatic blood flow were influenced by obstructive jaundice in a conscious canine model. Prior to biliary obstruction, portal venous blood flow (PVF) increased in response to the infusion of either dopamine or dobutamine: dopamine infused at 8 micrograms/kg per min produced an increase of 19 +/- 0% in PVF, while dobutamine infused at 16 micrograms/kg per min produced an increase of 30 +/- 2%. Although hepatic arterial blood flow (HAF) decreased dose-dependently in response to the infusion of dopamine, no significant change was observed in HAF in response to any dose of dobutamine. Obstructive jaundice attenuated or completely abolished the PVF-increasing effect of dopamine, whereas it did not significantly alter the effect of dobutamine on hepatic blood flow. In dogs with obstructive jaundice, dopamine at 16 micrograms/kg per min produced a decrease of 17 +/- 3% in PVF. These findings suggest that dobutamine is more effective than dopamine for increasing hepatic blood flow in patients with obstructive jaundice.

Animals↗
PubMed1996

Morphological and anthropological aspects of human triangular deciduous lower first molar teeth.

The crown and root morphology, and bilateral occurrence of human deciduous lower first molars that exhibited a triangular occlusal outline, taken from excavated samples of Japanese, Jomonese and Iraqi origin, were investigated. The crowns of triangular teeth had smaller mesiodistal and larger buccolingual diameters than normally shaped deciduous lower first molars. An elongated buccolingual diameter was derived from the buccal projection of the distobuccal cusp and lingual projection of the portion between the metaconid and distolingual cusp. In this analysis, all triangular deciduous lower first molars in which root morphology could be observed were accompanied by additional distolingual roots. Correlation between the right- and left-hand sides of this trait was high.

History, 15th Century↗
PubMed1996

Meanings of c-erbB and int-2 amplification in superficial esophageal squamous cell carcinomas.

BACKGROUND: Accumulation of genetic abnormalities is linked to the development and progression of cancer. We therefore analyzed the correlation between the clinical characteristics of superficial esophageal squamous cell carcinoma patients and oncogene amplifications. METHODS: Between 1980 and 1991, there were 63 cases of superficial esophageal carcinoma (Tis and T1 cancer) at Keio University Hospital. The T1 cases were divided into two groups: T1a cases, in which the tumor had invaded the lamina propria, and T1b cases, in which the tumor had invaded the submucosa. DNA was isolated from paraffin-embedded blocks. Oncogene amplification was determined by slot-blot hybridization. RESULTS: Amplification of int-2 and c-erbB was detected in 14 and 5, respectively, of the 54 cases. Three of 12 T1b patients with int-2 amplification died of distant organ metastasis. The survival rate for the group with int-2 amplification was significantly lower than that without int-2 amplification. All 4 T1b patients with c-erbB amplification had lymph node metastasis at operation. CONCLUSIONS: These findings mean that genetic abnormalities are a useful marker for treating patients with superficial esophageal squamous cell carcinomas.

Carcinoma, Squamous Cell↗
PubMed1996

Usefulness of fat-suppression magnetic resonance imaging for oral and maxillofacial lesions.

In magnetic resonance imaging (MRI) of the oral and maxillofacial region, where large amounts of fat are normally present, the high signal intensity of fat on T1-weighted images (T1WI) and the chemical-shift artifact have limited the utility of paramagnetic contrast agents. Eliminating fat signal by fat-suppression techniques can increase the value of contrast-enhanced MRI. The present study was designed to evaluate the utility and role of chemical-shift imaging for fat suppression in the detection of oral and maxillofacial lesions in 22 patients (17 with malignant tumors, two with benign tumors, and three with inflammation). The depiction of lesions on the postcontrast fat-suppression T1WI was compared with that of conventional pre- and postcontrast T1 and T2WI on a four-grade scale (grades 0-3). The postcontrast fat-suppression T1WI (average grade, 2.86) were significantly superior to the precontrast T1WI (0.82) and postcontrast T1WI (1.86) and T2WI (1.68). Postcontrast fat-suppression T1WI were particularly beneficial in the detection of central necrosis or extracapsular invasion of metastatic neck lymph nodes as well as in defining the lesion extent at fat-containing areas such as the bone marrow or cheek. These findings demonstrated that the fat-suppression technique is extremely useful in the delineation of oral and maxillofacial lesions without increase of the scan time or image postprocessing procedures.

Actinomycosis↗
PubMed1996

Evaluation of the genotoxicity of stevioside and steviol using six in vitro and one in vivo mutagenicity assays.

Stevioside, a constituent of Stevia rebaudiana, is commonly used as a non-caloric sugar substitute in Japan. The genetic toxicities of stevioside and its aglycone, steviol, were examined with seven mutagenicity tests using bacteria (reverse mutation assay, forward mutation assay, umu test and rec assay), cultured mammalian cells (chromosomal aberration test and gene mutation assay) and mice (micronucleus test). Stevioside was not mutagenic in any of the assays examined. The aglycone, steviol, however, produced dose-related positive responses in some mutagenicity tests, i.e. the forward mutation assay using Salmonella typhimurium TM677, the chromosomal aberration test using Chinese hamster lung fibroblast cell line (CHL) and the gene mutation assay using CHL. Metabolic activation systems containing 9000 g supernatant fraction (S9) of liver homogenates prepared from polychlorinated biphenyl or phenobarbital plus 5,6-benzoflavone-pretreated rats were required for mutagenesis and clastogenesis. Steviol was weakly positive in the umu test using S.typhimurium TA1535/pSK1002 either with or without the metabolic activation system. Steviol, even in the presence of the S9 activation system, was negative in other assays, i.e. the reverse mutation assays using S.typhimurium TA97, TA98, TA100, TA102, TA104, TA1535, TA1537 and Escherichia coli WP2 uvrA/pKM101 and the rec-assay using Bacillus subtilis. Steviol was negative in the mouse micronucleus test. The genotoxic risk of steviol to humans is discussed.

Animals↗
PubMed1996

Rapid diagnosis of methicillin-resistant Staphylococcus aureus bacteremia by nested polymerase chain reaction.

OBJECTIVE: The purpose of this study was to establish a rapid and sensitive diagnostic method for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in postoperative patients. SUMMARY BACKGROUND DATA: As a result of diffusion and abuse of third-generation cephalosporin antibiotics in the 1980s in Japan, an outbreak of MRSA infection has been posed. In the field of surgery, severe postoperative infections with MRSA such as MRSA bacteremia, which may lead to multiple organ failure, have emerged with a high mortality. METHODS: Thirty-five patients with high fever (above 38.5 C) or watery diarrhea or both within 2 weeks after gastrointestinal major surgery and 6 healthy volunteers were examined. Nested polymerase chain reaction was used to detect mecA and toxic shock syndrome toxin-1 (TSST-1) genes in blood specimens. RESULTS: The mecA and TSST-1 genes were not detected in the blood samples of any of the six healthy volunteers. In all 12 samples from which MRSA colonies were isolated by blood culture, mecA and TSST-1 genes were detected. Although it took at least 48 hours to identify MRSA by the blood culture method, the presence of mecA and TSST-1 genes was determined by nested polymerase chain reaction method within only 3 to 4 hours after blood sampling. CONCLUSIONS: This method, as a sensitive and rapid monitoring system for MRS bacteremia, would be clinically beneficial for prevention of cross infection and for early determination of appropriate treatment for infected patients.

Bacteremia↗
PubMed1996

Synthesis of secretory protein in regenerating liver of rat after partial hepatectomy.

Albumin immunoreactivity in the liver was examined on days 2, 5 and 10 after two-thirds partial hepatectomy by light and ultrastructural immunoperoxidase methods and the ultrastructural area of the rough endoplasmic reticulum (ER) in hepatocytes was measured. Albumin immunoreactivity was seen in the rough ER and Golgi apparatus of all hepatocytes in the hepatectomized liver and ultrastructural analysis showed a significantly greater area of rough ER on day 5 than on days 2 or 10. Albumin mRNA was studied by the in situ hybridization technique using radioisotopes and their numbers were determined visually. Albumin mRNA was present as grains in all hepatocytes and the grains varied in number during regeneration of the liver, being more abundant on day 5 than on days 2 or 10. The activity of [3H]-leucine incorporated into albumin synthesis, an indicator of translational activity, was higher on days 5 and 10 than on day 2 and was highest on day 5. In conclusion, albumin synthesis varied during liver regeneration after partial hepatectomy, being reduced at the peak of cell proliferation on day 2 and being most active on day 5.

Albumins↗
PubMed1996

Overexpression of Bcl-2 and mutations in p53 and K-ras in resected human non-small cell lung cancers.

We investigated expression of Bcl-2, mutations in p53, and K-ras oncogene in 51 resected human non-small cell lung cancers. The studies were designed to test for the possibility of cooperativity between these oncogenes and p53 in the pathogenesis of lung cancer. An inverse relationship was found between expression of Bcl-2 and mutant p53 by immunohistochemistry (P < 0.01; Fisher exact test), suggesting that either Bcl-2 overexpression or mutations in p53 may fulfill a critical function in the pathogenesis of human non-small cell lung cancers. Tumors that harbored K-ras codon 12 mutations seldom had p53 mutations or overexpressed Bcl-2. Statistical analysis of these data showed that mutations in p53 and K-ras or overexpression of Bcl-2 and mutations in K-ras occurred at a frequency that could be explained only by chance [P > 0.1 in each case (Fisher exact tests)]. This suggests that cooperativity between mutant K-ras and mutant p53 or mutant K-ras and overexpressed Bcl-2 is not a common mechanism in the pathogenesis of human non-small cell lung cancers.

Adenocarcinoma↗
PubMed1996

Repressor-like factor that interacts with SV40 promoter/enhancer and expressed during differentiation of embryonal carcinoma F9 cells.

Transient expression of the chloramphenicol acetyltransferase gene (cat) under the control of Simian virus 40 early enhancer/promoter complex (pAOcat) was stimulated initially by differentiation of F9 cells into primitive endoderm, but it was repressed by further differentiation into visceral endoderm. Deletion of the 72-base pairs of enhancer reduced cat expression, but the dependence on differentiation was still observed. Gel retardation assays using enhancer or promotor sequences revealed nuclear factors expressed in undifferentiated (stem) and visceral endoderm F9 cells. Co-transfection of pAOcat with an excess of promoter or enhancer sequence stimulated cat expression. Thus, repressor-like factors were suggested to be responsible for the differentiation-dependent control.

Carcinoma, Embryonal↗
PubMed1996

Pericytes from microvessel fragment produce type IV collagen and multiple laminin isoforms.

In the microvascular system, pericytes are located at the abdominal side of capillary endothelial cells. To discover the role of pericytes in the microvascular system, we have analyzed the extracellular proteins secreted from pericytes isolated from microvessel fragments of rat epididymal fat pads and found that they synthesize substantial amounts of basement membrane components such as type IV collagen and laminins. Secretion of type IV collagen was markedly stimulated by ascorbic acid phosphate. Reducing and nonreducing sodium dodecyl sulfate gel electrophoresis showed that pericytes produce six laminin chains assembled into different trimeric isoforms. Two of them were similar to laminin variants produced by aortic and pulmonal endothelial cells but others were suggested to be novel variants.

Adipose Tissue↗
PubMed1996

Treatment of essential and parkinsonian tremor with nipradilol.

Nipradilol is a new type of beta-blocker which possesses nitroglycerin-like vasodilating action in addition to beta-blocking action. We investigated the efficacy and safety of nipradilol for treating tremor in 20 patients with essential tremor (ET group) and 20 patients with Parkinson's disease (PD group). All patients received nipradilol (6 mg per day) for more than 8 weeks. Improvement of tremor appeared within 2 or 4 weeks after the start of nipradilol therapy, and the efficacy rate, defined as "moderately effective" or over, was 42.5% in all 40 patients, while that defined as "slightly effective" or over was 87.5%. The efficacy rate tended to be higher in the ET group compared with the PD group. Mean blood pressure was significantly decreased from the 4th week after the start of treatment and heart rate was significantly reduced from the 2nd week of treatment. Laboratory examination showed no significant changes.

Adrenergic beta-Antagonists↗
PubMed1996

[Oligospermia improved by switching an anticonvulsant from phenytoin to valproate].

We report a case of 30-year-old man with generalized seizure, who had received phenytoin (PHT) for more than 6 years, but developed decrease in sperm count and motility. After PHT had been discontinued and valproate (VPA) had been administered for 3 months, his sperm activity became normalized. The decrease in sperm motility was the most important cause of his infertility. Sperm motility has been reported to be inversely correlated with the ratio of the concentrations of antiepileptic drugs in the plasma and semen. In our case, the ratio was 0.21 for PHT and 0.08 for VPA. We wish to emphasize the importance of measuring the concentration of antiepileptic drugs in the semen of infertile young males if they are on anticonvulsants.

Adult↗
PubMed1996

Immunological discrimination of diverse forms of human alpha 1-proteinase inhibitor.

The immunodiffusion cross-reactivity and competitive inhibition ELISA assays were used for immunological differentiation of latent form, cleaved form and guanidinium hydrochloride (GuHCl) induced polymer of human alpha 1-proteinase inhibitor (alpha 1-PI). Under the conditions studied, the differences between latent form and GuHCl-induced polymers of the inhibitor in terms of immunological response were estimated to amount to about 30% and differences between latent and cleaved alpha 1-PI to about 50%. The immunodiffusion and ELISA data for citrate-induced polymers suggest that in their structure the latent molecule is involved. On the basis of competitive inhibition data, we suggest that the alpha 1-PI protein polymerisation involves insertion of the reactive-site loop (RSL) into the A-sheet under mild conditions and that in the latent form of the inhibitor RSL is incompletely inserted into the A-sheet.

Cross Reactions↗
PubMed1996

Radioimmunoprecipitation assay for glutamic acid decarboxylase antibodies evaluated clinically with sera from patients with insulin-dependent diabetes mellitus.

We evaluated a new, commercially developed radioimmunoprecipitation assay for measuring glutamic acid decarboxylase (GAD) antibodies by using recombinant human GAD65. The intra- and interassay CVs were 8.0% (n = 20) and 8.6% (n = 15), respectively. We found GAD antibodies in 74% (23 of 31; 95% confidence interval 55-88%), 70% (14 of 20; 46-88%), and 65% (28 of 43; 49-79%) of patients at, respectively, < or = 1 year, 1-2 years, and 2-4 years after the onset of insulin-dependent diabetes mellitus (IDDM) and in 30% (30 of 99; 21-40%) of patients with long-term diabetes (4-22 years). We also detected GAD antibodies in 8% (9 of 106; 4-16%) of patients with non-insulin-dependent diabetes mellitus (NIDDM). The frequency of GAD antibodies in the NIDDM group was markedly higher in the insulin-deficient patients [67% (6 of 9; 30-93%)], who initially were nonketotic and non-insulin-dependent for > or = 6 months but later became insulin dependent, than in the non-insulin-deficient patients [3% (3 of 97; 1-9%)]. This new commercial assay is easy to use and provides a specific and sensitive method for evaluating GAD antibodies in IDDM.

Adolescent↗
PubMed1996

Further evidence for prognostic significance of epidermal growth factor receptor gene amplification in patients with esophageal squamous cell carcinoma.

To determine the value of epidermal growth factor receptor (EGFR) gene amplification as a biological prognostic indicator in patients with esophageal squamous cell carcinoma, the EGFR gene amplification was determined by slot-blot hybridization using DNA extracted from formalin-fixed and paraffin-embedded blocks of tissues from 107 patients with esophageal squamous cell carcinoma who had undergone curative surgery. Results were analyzed by both univariate and multivariate statistical analysis. EGFR gene amplification greater than 3-fold was detected in the primary tumors of 13 (12%) of the 107 cases. The cumulative survival rate for patients with EGFR gene amplification in the primary tumors was significantly lower than that for patients without amplification (P < 0.001). A significant correlation was observed between extensive lymph node involvement at the time of surgery and EGFR gene amplification (P < 0.05). In the multivariate analysis, EGFR gene amplification (P = 0.015) and vascular invasion (P = 0.003) proved to retain independent prognostic values. These results suggest that EGFR gene amplification may be a useful biological marker for the prediction of lymph node metastasis and a poorer prognosis of esophageal squamous cell carcinoma.

Adult↗
PubMed1995

Expression of messenger RNA encoding a paraneoplastic cerebellar degeneration-associated antigen in the rat hippocampus.

The PCD17 protein is a paraneoplastic cerebellar degeneration (PCD)-associated neural autoantigen which is recognized by autoantibodies in sera of PCD patients. The localization of the PCD17 mRNA was examined by in situ hybridization histochemistry using a PCD17 cRNA probe. In the cerebellum, the localization of the transcript was in agreement with the distribution of PCD17-immunoreactivity. On the other hand, intense hybridization signals were detected in most of cells in the hippocampus in which notable PCD17-immunoreactivity was undetected. These observations suggest that some negative translational or post-transcriptional mechanisms of the PCD17 mRNA may be involved in neurons of the hippocampus.

Animals↗