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Biomedical subjects

J Watanabe

Publications and source records attributed to J Watanabe.

At least 253 records · Page 14Linked to original sources
PubMed1994

Quantitative assessment of influence of aging on optokinetic nystagmus.

A quantitative assessment of the influence of aging on optokinetic nystagmus (OKN) was investigated using 50 normal adults in ages ranging from 30 to 70 years. In linear stimulus-induced OKN, a statistically significant difference was demonstrated in slow-phase OKN velocity only between the 30-59 year old age group and the 70-79-year-old age group, when OKN stimulus was more than 60 degrees/s. Step stimulus-induced OKN was investigated in the same age groups in order to compare aging effects upon slow-phase OKN velocity. No statistically significant difference was found in slow-phase OKN velocity between younger age groups and the oldest age group. There was no significant difference in fast-phase velocity among the age groups. Thus, step-induced OKN has a wider clinical application than linear stimulus-induced OKN.

Adaptation, Physiological↗
PubMed1994

Rebound positional nystagmus as a peripheral origin.

Three cases of rebound positional nystagmus (RPN) are discussed in the present study. In all cases, spontaneous nystagmus was absent in the primary position, but positional nystagmus appeared in the side down position, and then nystagmus in the reversed direction appeared when the patient was returned to the primary position. The characteristics of RPN in the cases we studied were very similar to those of benign positional nystagmus. Tinnitus was accompanied with vertigo in Cases 2 and 3, and the glycerol tests were positive in Cases 1 and 3. There were no other abnormalities of ocular movements, neurological and neuroradiological examinations suggestive of central nervous system disorders indicating that RPN can be ascribed to peripheral lesions. A selective review of the literature is presented.

Electrooculography↗
PubMed1994

Panclicins, novel pancreatic lipase inhibitors. I. Taxonomy, fermentation, isolation and biological activity.

Panclicins A, B, C, D, and E are novel pancreatic lipase inhibitors isolated from Streptomyces sp. NR 0619. Structurally, panclicins A, B, C, D, and E are analogues of tetrahydrolipstatin (THL), which contains a beta-lactone and a N-formyl leucine ester, and the IC50s of panclicins A, B, C, D, and E for porcine pancreatic lipase are 2.9, 2.6, 0.62, 0.66, and 0.89 microM, respectively. The potency of the inhibitory activity of each compound is attributed to the amino acid moiety of each structure. The panclicins are either glycine-type compounds such as panclicins C, D, E, which are two to threefold more potent than THL, or they are alanine-type compounds such as panclicins A and B, which are less potent than the glycine compounds. The inhibitory profiles of the panclicins for other lipases such as post-heparin plasma lipases and bacterial lipases are similar to those for pancreatic lipase. Panclicins A, B, C, D, and E, in a manner similar to THL, irreversibly inhibit pancreatic lipase. However, the compounds don't irreversibly inhibit the enzyme as strongly as THL does.

Animals↗
PubMed1994

Panclicins, novel pancreatic lipase inhibitors. II. Structural elucidation.

Panclicins A-E are novel and potent pancreatic lipase inhibitors produced by Streptomyces sp. NR 0619. Their structures have been elucidated based on NMR and FAB-MS experiments. The relative configurations have also been determined by NMR experiments. The absolute stereochemistry has been determined by the chiral HPLC analysis of the hydrolysates of panclicins A and B and by modified Mosher's method on a derivative of panclicin A. They are structurally related to beta-lactone esterase inhibitors of microbial origin, lipstatin, valilactone, ebelactones and esterastin. Panclicins also contain a beta-lactone structure with two alkyl chains, one of which has an N-formylalanyloxy or N-formylglycyloxy substituent.

Lactones↗
PubMed1994

Application of the random amplified polymorphic DNA using the polymerase chain reaction for efficient elimination of duplicate strains in microbial screening. II. Actinomycetes.

We evaluated the random amplified polymorphic DNA (RAPD) method using Streptomyces lavendulae and Streptomyces virginiae strains to eliminate duplicate actinomycete strains in our microbial screening program. The RAPD data were compared with phenotypic characteristics, DNA relatedness, HPLC analysis of metabolites and low-frequency restriction fragment analysis by pulsed-field gel electrophoresis. These results were consistent with each other. Therefore, we conclude that RAPD is a simple, efficient, and reliable method for the selection of actinomycete strains.

Base Sequence↗
PubMed1994

Cyclothialidine, a novel DNA gyrase inhibitor. II. Isolation, characterization and structure elucidation.

Cyclothialidine is a novel DNA gyrase inhibitor produced by Streptomyces filipinensis NR 0484. It was isolated from the culture broth by charcoal adsorption, Diaion HP-21, Amberlite CG-50, DEAE Toyopearl, and Toyopearl HW-40 SF column chromatography. The structure of cyclothialidine was determined to be a unique twelve membered lactone by amino acid analysis and various 2D-NMR experiments. Cyclothialidine inhibited Escherichia coli DNA gyrase with an IC50 of 30 ng/ml.

Amino Acid Sequence↗
PubMed1994

[Semi-radical transurethral resection of the prostate for small benign prostatic hyperplasia].

The conventional method of transurethral resection of the prostate (TUR-P) is often not beneficial for small benign prostatic hyperplasia (BPH) because of a high frequency of postoperative bladder neck contracture (BNC). Herein, we examined the usefulness of semi-radical transurethral resection of the prostate (semi-radical TUR-P) from the view points of improvement of peak flow rate, the frequency of postoperative BNC and incidental carcinoma of the prostate in 79 cases of small BPH (group A) and 101 cases (group B) of large BPH in which less than 10 g for more than 10 g of the internal glands was resected, respectively. The bladder neck was resected carefully to avoid over resection which may cause BNC in small BPH cases. Satisfactory results were obtained in both groups, that is, the improvement of the peak flow rate from 7.03 +/- 3.79 ml/sec to 13.9 +/- 7.32ml/sec and from 4.96 +/- 2.88 ml/sec to 15.2 +/- 8.30 ml/sec, and the frequency of BNC were 2.53% (2/79) and 1.98% (2/101) in groups A and B, respectively. The frequency of incidental carcinoma of the prostate were 15.2% (12/79) and 17.8% (18/101) in groups A and B. We conclude that semi-radical TUR-P is a favorable maneuver for small BPH because of satisfactory improvement in peak flow rate with low frequency of postoperative BNC and its superiority in screening test for incidental carcinoma of the prostate.

Aged↗
PubMed1994

[Influence of liver function on stereotactic microwave tissue coagulation therapy for hepatocellular carcinoma].

We studied 21 cases of hepatocellular carcinoma with liver cirrhosis to investigate the influence of liver function on stereotactic microwave tissue coagulation therapy. The cases were divided into three groups by the operation. The first group received only hepatectomy, the second hepatectomy and coagulation therapy for any remaining tumor, and the third group received only coagulation therapy. In group one, the average value of ICG R15 increased from 26.6% to 33.8%. In group 2, the average value of ICG R15 increased from 18.9% to 32.1%. And in group 3, the initial ICG R15 was 26.1%; after four weeks, the ICG test was 25.4%. These results showed that coagulation therapy alone had less influence on hepatic function. We propose that the coagulation therapy should be selected for cases of HCC with liver cirrhosis which have a poor liver function.

Aged↗
PubMed1994

Clinicopathologic study on lymph node metastasis of hepatocellular carcinoma: a retrospective study of 660 consecutive autopsy cases.

There have been few reports in the literature concerning lymph node metastasis (LM) in hepatocellular carcinoma (HCC). Nowadays, hepatectomy has become one of the most popular treatments for HCC, and understanding LM in HCC is indispensable at surgery for improving the patient's prognosis. In the present study, the authors verified this using autopsy cases. The clinicopathologic characteristics of LM have been studied in 660 consecutive autopsy cases of HCC at Kurume University Hospital during the past 22 years. LM was noted in 168 (25.5%) of the 660 cases, and was most frequent (66.7%) in HCCs of the pedunculated type. The incidence of LM was significantly higher in the massive type of HCC (30.1%) than the nodular type (19.9%) (P < 0.05). The incidence of LM was also higher in non-cirrhotic (34.8%) than cirrhotic cases (23.5%) (P < 0.05). No metastasis was found in tumors less than 3 cm in diameter. The metastasis rate increased to 40% in tumors larger than 10 cm in diameter. The LM sites were peripancreatic, 13.6%; hepatic hilar, 13.5% and perigastric, 10.8%. The incidence of LM in the perigastric nodes was significantly higher in tumors located in the left hepatic lobe. LM was not found in well-differentiated HCCs but was frequently found in poorly-differentiated HCCs. Extensive LM was found in 60% of HCCs with sinusoidal tumor growth and in 57% of cases showing sarcomatous changes.

Aged↗
PubMed1993

Tetrafibricin: a nonpeptidic fibrinogen receptor inhibitor from Streptomyces neyagawaensis (I). Its GPIIb/IIIa blockage on solid phase binding assay.

Tetrafibricin is a novel nonpeptidic fibrinogen receptor inhibitor isolated from Streptomyces neyagawaensis NR0577. Its competitive and selective fibrinogen receptor blockage was demonstrated in this study. Tetrafibricin competitively inhibited (Ki = 9.9 nM) the binding of biotinylated fibrinogen to purified active glycoprotein (GP) IIb/IIIa immobilized on plastic plate. When RGDS and tetrafibricin were added in combination, the inhibition was additive. The binding of other RGD-containing proteins, fibronectin and von Willebrand factor, to active GPIIb/IIIa were also completely inhibited by tetrafibricin. The fact that tetrafibricin did not inhibit the binding of von Willebrand factor to GPIb/IX indicates the specific blockage of tetrafibricin for GPIIb/IIIa. Fibrinogen receptor inhibition of tetrafibricin was also confirmed by its ability to inhibit 125I-fibrinogen binding to platelets stimulated with ADP. Because of its competitiveness and specificity, tetrafibricin can be used in a new structural model for the design of fibrinogen receptor inhibitors.

Adenosine Diphosphate↗
PubMed1993

Bioimpedance monitoring of rehydration in cholera.

Measurement of bioimpedance (BI) is a simple non-invasive technique that relies on the different conductivity of tissues to define body composition and can be easily adapted to automated monitoring. We assessed the accuracy of BI in monitoring rehydration and acute fluid fluxes in 35 Peruvian cholera patients. Patients were monitored throughout the acute phase of diarrhoea and followed up at 3 and 10 days. BI was compared with other objective measures of dehydration including packed cell volume, serum protein, and calculated fluid balance. BI rapidly detected inadequate treatment and acute fluid flux, correlating highly with intravascular hydration as measured by serum protein and packed cell volume. BI values during dehydration were significantly raised compared with 10-day convalescent values and age-matched controls (p < 0.05). We also encountered an unexpected difference in the bioelectrical response to dehydration and rehydration between sexes. We conclude that BI has uses in monitoring dehydrated patients, in oral rehydration trials, and in physiological studies.

Acute Disease↗
PubMed1993

Nd:YAG laser trabeculopuncture (YLT) for glaucoma with traumatic angle recession.

Traumatic angle recession caused by blunt trauma often induces uncontrollable glaucoma despite the maximum medical therapy tolerated, such as argon laser trabeculoplasty (ALT), with no or little benefit. Therefore, instead of ALT, we tried Nd:YAG laser trabeculopuncture (YLT) on 11 patients with this type of glaucoma. The intraocular pressure of these patients was followed up for 15 +/- 7 months (average +/- SD). In 6 of 7 eyes treated initially with YLT, the IOP was significantly reduced, so medication was discontinued. Four other cases with uncontrollable IOP after failed ALT were treated with YLT. The IOP of 3 cases was successfully controlled by medication after YLT. These YLT results were then compared with those of ALT in 11 glaucoma patients with traumatic angle recession. Seven of 11 cases treated initially with ALT failed in less than 3 months, and surgical intervention or additional laser treatments were required. The probability of success from the time-series analysis at 12 months after each laser application was 0.909 in YLT, 0.273 in ALT. YLT offers significant advantages over ALT for the treatment of glaucoma with traumatic angle recession after blunt trauma and thus merits further study.

Adolescent↗
PubMed1993

Apolipoprotein E polymorphism affects the response to pravastatin on plasma apolipoproteins in diabetic patients.

In the present study, we examined the levels of plasma lipids and apolipoproteins in patients with non-insulin dependent diabetes mellitus (NIDDM) with hypercholesterolemia in different apolipoprotein E (apo E) phenotypes. We also examined the influences of apo E polymorphism on the response to pravastatin. The patients were divided into three groups, E4/E3, E3/E3, and E3/E2. There were no differences in the baseline levels of plasma lipids and apolipoproteins, except that the level of triglycerides in E3/E2 heterozygotes was significantly higher than E3/E3 homozygotes. Three months of pravastatin administration significantly reduced plasma levels of total cholesterol and low-density lipoprotein cholesterol in each group to the same degree. We observed a significant reduction of apo B both in the E4/E3 and E3/E3 groups and apo E in the E3/E3 group. Such reduction was not observed in the E3/E2 group. We conclude that pravastatin is a potent drug to correct lipid abnormalities, particularly in NIDDM patients with apo E4/E3 and E3/E3. In the E3/E2 group, its effectiveness may be diminished.

Adult↗
PubMed1993

Effect of zatebradine on contractility, relaxation and coronary blood flow.

OBJECTIVES: The purpose of this study was to compare the effects of zatebradine on heart rate, contractility and relaxation with those of its structural analog verapamil. We used isoproterenol, a potent beta-agonist, to see how these effects were modulated by sympathetic activation. We also compared the effects of zatebradine and verapamil on coronary blood flow and coronary blood flow reserve. BACKGROUND: Zatebradine, previously called UL-FS 49, is a new bradycardic agent believed to act selectively at the sinoatrial node. METHODS: Isolated isovolumetric pig hearts were prepared and left ventricular pressure, its first derivative (dP/dt), tau and heart rate were measured both before and after administration of either 0.975 mg of zatebradine (Group I, n = 8) or 125 micrograms of verapamil (Group II, n = 8). After the effects of each drug reached a plateau, a continuous infusion of isoproterenol was started and measurements were obtained again and compared with a third group of measurements from control hearts infused with isoproterenol after receiving only saline solution (n = 8). We also assessed the effects of zatebradine and verapamil on coronary vascular tone by measuring flow in the left anterior descending coronary artery in intact anesthetized open chest pigs both before and after the intracoronary administration of these drugs (n = 8 for each). All preparations were atrially paced to negate any bradycardiac effects of the drugs. RESULTS: In the group that received zatebradine, mean (+/- SE) heart rate decreased from 143 +/- 8 to 99 +/- 4 beats/min (p < 0.01) and there was no significant change in either peak left ventricular systolic pressure, dP/dt or tau. In contrast, verapamil produced a lesser decrease in heart rate (136 +/- 7 to 120 +/- 7 beats/min, p < 0.05) but produced substantial decreases in peak left ventricular pressure (100 +/- 3 to 45 +/- 4 mm Hg, p < 0.01) and dP/dt (68% decrease, p < 0.01) and an increase in tau (+26%, p < 0.05). Isoproterenol restored these variables toward normal values in the hearts treated with verapamil, although left ventricular systolic pressure and dP/dt were restored to control values only at the highest isoproterenol concentrations. In the hearts treated with zatebradine, isoproterenol significantly increased left ventricular pressure and contractility and decreased tau; however, heart rate remained unchanged at peak effect. Zatebradine had no effect on coronary blood flow and there was a 100% increase in flow with reactive hyperemia. Conversely, verapamil increased coronary flow by 100%, with no subsequent further increase by reactive hyperemia compared with control values. CONCLUSIONS: Although structurally similar to verapamil, zatebradine is a highly specific bradycardic agent. It has little direct effect on left ventricular developed pressure, contractility, relaxation and coronary vascular tone. Furthermore, the bradycardic effect of zatebradine unlike that of verapamil, is not overcome by doses of isoproterenol that increase developed pressure and contractility and improve relaxation. Because of its highly specific bradycardic effect, this drug may potentially be useful in treating patients with ischemic heart disease or congestive heart failure.

Animals↗
PubMed1993

The CYP1A1 gene and cancer susceptibility.

A close correlation between cigarette smoking associated lung cancer incidence and an Msp I restriction fragment length polymorphism (RFLP) of the human P-450 1A1 (CYP1A1) gene was found in a Japanese population in terms of genotype frequency and cigarette dose. A Val/Ile codon difference in the primary structure of the CYP1A1 protein (Val-, Ile-type) was in linkage disequilibrium with the Msp I RFLP. A synergistic increase in susceptibility to lung cancer was found when combining genotyping of CYP1A1 and the Mu-class of glutathione S-transferase (GST1). Interindividual variability in the genetic make-up of carcinogen metabolizing enzymes may thus be a key host factor to explain the differences in susceptibility to chemical carcinogenesis among individuals.

Cytochrome P-450 Enzyme System↗
PubMed1993

Quantitative analysis of smooth endoplasmic reticulum proliferation in periportal, midzonal and perivenular hepatocytes of mice after administration of phenobarbital.

Smooth endoplasmic reticulum (SER) proliferation after phenobarbital (PB) administration has been described to occur predominantly in perivenular hepatocytes. We analyzed by quantitative electron microscopy changes in ER amounts in periportal, midzonal and perivenular hepatocytes from mice injected with 35, 50, 100 or 150 mg/kg of PB once a day for 3 days. The SER proliferated in midzonal hepatocytes in addition to perivenular hepatocytes even when low doses (35 or 50 mg/kg) were administered, and in hepatocytes of all three zones in case of high doses (100 or 150 mg/kg). Moreover, net proliferation of SER after administration of an amount of PB was not different in hepatocytes of any zones where the proliferation occurred, except animals injected with 100 mg/kg. The results suggest that there is no difference in SER producing capacity in hepatocytes of three zones when the cells have recognized the stimulation of PB.

Animals↗