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Biomedical subjects

Y Noguchi

Publications and source records attributed to Y Noguchi.

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

The effects of stimulus rates upon median, ulnar and radial nerve somatosensory evoked potentials.

We examined the effect of stimulus rates on the somatosensory evoked potential (SEP) amplitude following stimulation of the median nerve (MN) and the ulnar nerve (UN) at the elbow or wrist, and the radial nerve (RN) at the wrist in 12 normal subjects. We measured the amplitude of frontal (P14-N18-P22-N30) and parietal peaks (P14-N20-P26-N34) at a stimulus rate of 1.1, 3.5 and 5.7 Hz. The amplitude attenuation was found at frontal P22 and N30 and to a lesser degree at parietal N20 and P26 peaks with an increasing stimulus rate from 1.1 to 5.7 Hz. The amplitude attenuation was greatest at the elbow when compared to the wrist stimulation for both MN and UN. The attenuation was least for wrist stimulation for the RN. The UN block by local anesthesia just distal to the stimulus electrode at the elbow abolished the amplitude attenuation caused by the fast stimulus rate. The observed amplitude attenuation with the faster stimulus rate is probably due, in part, to interference from the "secondary" afferent inputs. The secondary afferent inputs arise from peripheral receptor stimulation (muscle, joint and/or cutaneous) as a subsequent effect of efferent volleys initiated from the point of stimulation. The greater number of peripheral receptors being activated as more proximal sites of stimulation in a mixed nerve would result in greater attenuation of the SEP recorded from scalp electrodes. We postulate that the attenuation of frontal peaks by the fast stimulus rate is due to the frontal projection of interfering "secondary" afferent inputs.

Adult↗
PubMed1994

Sepsis increases production of total secreted proteins, vasoactive intestinal peptide, and peptide YY in isolated rat enterocytes.

The effect of sepsis on the synthesis of endogenous and secretory proteins, including vasoactive intestinal peptide (VIP) and peptide YY (PYY), was determined in enterocytes from jejunum of rats. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. Total endogenous and secreted protein synthesis was assessed in incubated jejunal enterocytes by measuring incorporation of 3H-phenylalanine into protein. Release of VIP and PYY into the medium of incubated enterocytes and cellular levels of the gut peptides were measured by radioimmunoassay. Sixteen hours after CLP, synthesis rates of both endogenous and secreted proteins were increased, and this effect of sepsis was most pronounced in cells from the lower parts of the villi and crypts. Enterocytes from septic rats released more VIP and PYY into the incubation medium, and approximately half of the peptides they released were newly synthesized VIP and PYY. Intracellular levels of VIP and PYY were increased as early as 4 hours after induction of sepsis. Our results suggest that sepsis stimulates the synthesis of endogenous and secretory proteins, including certain gut peptides, in small intestine mucosa. This is consistent with previous observations of increased circulating levels of VIP, PYY and other gastrointestinal hormones during sepsis. The biological significance of increased synthesis of gut peptides and other intestinal proteins during sepsis remains to be determined.

Analysis of Variance↗
PubMed1994

Effect of sepsis on mucosal protein synthesis in different parts of the gastrointestinal tract in rats.

1. In a previous study we found that the protein synthesis rate was increased by 50-60% in the mucosa of the jejunum and ileum during sepsis in rats. It is not known if sepsis affects protein turnover in other parts of the gastrointestinal tract as well. 2. In the present study, the influence of sepsis on mucosal protein synthesis in different parts of the gastrointestinal tract, from the stomach to the rectum, was determined in rats. 3. Sepsis was induced by caecal ligation and puncture; control rats underwent sham-operation. Protein synthesis rate was measured in vivo after administration of a flooding dose of [14C]leucine. 4. Basal mucosal protein synthesis rates were lower in the colon than in the rest of the gastrointestinal tract. Sixteen hours after caecal ligation and puncture, the protein synthesis rates were increased by 40-85% in the mucosa of the small and large intestine and the rectum, whereas in the gastric mucosa, the protein synthesis rate was reduced by approximately 40%. 5. The results suggest that mucosal protein synthesis rates differ in the various regions of the gastrointestinal tract, and that the metabolic response to sepsis is different in the stomach than in the rest of the gastrointestinal tract. The finding of a reduced protein synthesis rate in the gastric mucosa may partly explain the tendency to gastric stress ulcers and bleeding seen clinically in sepsis.

Animals↗
PubMed1994

Endoscopic resection of early gastric carcinoma: results of a retrospective analysis of 308 cases.

The purpose of this study was to define the indications and limitations of endoscopic resection (ER) of early gastric carcinoma (EGC). Over the 15 year period from 1978 to 1992, 308 early cancers were resected endoscopically either through a single operative intervention or in stages. Of 266 lesions resected in a single step, 222 (85%) entered remission. Forty-four cases had either residual or recurrent lesions. The size, histology and location affected the curability; 89% of Type IIa lesions less than 2 cm were resected curatively, while only 50% of those larger than 2 cm were resected completely. In Type IIc, 83% of lesions less than 1 cm and 57% of those greater than 1 cm were excised completely by ER. In Type IIc, curative ER was possible in 85% of differentiated carcinomas and 43% of undifferentiated carcinomas. The rate of incomplete resection was higher for lesions of the anterior or posterior wall, than for those of the lesser curvature. Semiserial sections of the resected specimens made at 2 mm intervals, indicated that, if the positive margin was confined to one section, cure may be possible by the burning effect. Follow-up showed that there was no single case undergoing endoscopic resection which subsequently died of gastric carcinoma. The lesions that are suitable for ER comprise Type IIa EGC of less than 2 cm in diameter, and Type IIc differentiated adenocarcinoma of less than 1 cm. Lesions in which the entire margin is difficult to observe by front-view endoscopy should be smaller than defined by the above criteria.

Adenocarcinoma↗
PubMed1994

Enhanced vascular permeability in solid tumor is mediated by nitric oxide and inhibited by both new nitric oxide scavenger and nitric oxide synthase inhibitor.

A newly discovered nitric oxide radical scavenger, an imidazolineoxyl N-oxide derivative, was used to investigate the role of nitric oxide radical (.NO) in the vascular permeability enhancement of solid tumor. Sarcoma-180 solid tumor in ddY mice was used for this experiment. Electron spin resonance spectroscopy was used to quantitate the reacted and unreacted scavenger. The results showed that extensive extravasation, assessed by intravenous injection of Evans blue, could be greatly suppressed by both .NO scavenger administered orally and .NO synthase inhibitor administrated intraperitoneally. This indicates that .NO is responsible for the vascular permeability in solid tumors.

Amino Acid Oxidoreductases↗
PubMed1994

Hereditary nephrotic syndrome with progression to renal failure in a mouse model (ICGN strain): clinical study.

The clinical course of murine hereditary nephrotic syndrome (ICGN strain) was determined by examining 201 animals under different conditions. In the early stage, significant hypoproteinemia and hypoalbuminemia developed (p < 0.001) in parallel with a progressive rise in urinary protein concentration (p < 0.001). In the middle stage, the concentrations of total cholesterol, triglyceride, and beta-lipoprotein markedly increased (p < 0.01, p < 0.001, and p < 0.001, respectively), suggesting that type IIb hyperlipoproteinemia developed as in human nephrotic patients. Systemic edema appeared in 8 of 24 animals. In the terminal stage, both BUN and creatinine values greatly increased (p < 0.001), indicating rapid deterioration of renal function. The present study suggests that ICGN mice could be a useful model to study the pathophysiology of human nephrotic syndrome and its progression to renal failure.

Animals↗
PubMed1994

[Acidified aspirin-induced gastric lesion in rats with hepatic cirrhosis produced by N-nitrosodiethylamine or carbon tetrachloride. Effect of aldioxa on gastric lesions].

Gastric lesion was induced by the oral administration of acidified aspirin in rats with hepatic cirrhosis produced by N-nitrosodiethylamine (NDA) or carbon tetrachloride (CCl4). Gastric lesion by acidified aspirin was aggravated in NDA-induced cirrhosis, but not in CCl4-cirrhotic rats. To clarify this difference in the susceptibility of the gastric mucosa, gastric mucosal blood flow and gastric emptying were measured by the hydrogen gas clearance method and beads method, respectively. Gastric mucosal blood flow was lower and gastric emptying was significantly delayed in NDA-induced cirrhotic rats as compared with the controls, but not in CCl4-induced cirrhotic rats. Gastric mucosal blood flow in NDA-induced cirrhotic rats was significantly decreased by the oral administration of acidified aspirin as compared with the controls. Aldioxa dose-dependently inhibited the gastric lesion formation by acidified aspirin and inhibited the decrease of gastric mucosal blood flow in NDA-induced cirrhotic rats. These results suggest that aggravation of gastric lesion induced by acidified aspirin in NDA-induced cirrhotic rats would be due to the decrease of gastric mucosal blood flow and delay of gastric emptying. In addition, aldioxa showed a protective effect against gastric lesions induced by acidified aspirin in NDA-induced cirrhotic rats, suggesting that this compound would have an inhibitory effect on gastric lesions that are accompanied by hepatic cirrhosis.

Allantoin↗
PubMed1994

[Effect of Y-20811, a thromboxane A2 synthetase inhibitor, on the arachidonic acid-induced response in the blood-superfused canine coronary artery].

Effects of Y-20811, a thromboxane A2 synthetase inhibitor, on the arachidonic acid (AA)-induced responses were investigated in the isolated canine coronary artery superfused with blood from a donor dog and Krebs-Henseleit solution. When the coronary artery was superfused with Krebs-Henseleit solution, AA did not have any remarkable effect on its tone. In the coronary artery superfused with blood, in contrast, AA (10-100 micrograms) caused phasic constriction followed by relaxation. After denudation of the endothelium, the contractile response was augmented, and the relaxant effect was abolished. Y-20811 (1 mg/kg, i.v.), administered into the donor dog, inhibited the contraction and augmented the relaxation. Indomethacin (5 mg/kg, i.v.) and aspirin (30 mg/kg, i.v.) also inhibited the AA-induced contraction. However, indomethacin inhibited the relaxation induced by AA (10-100 micrograms), whereas aspirin inhibited the relaxation induced by a low dose of AA (10-30 micrograms). These results suggest that Y-20811 inhibits the TXA2-induced contraction and augments the production of the relaxant metabolite of AA in the coronary artery.

Animals↗
PubMed1994

[A new electrode (HN-5) for CM measurement in extra-tympanic electrocochleography].

A new electrode (HN-5) for CM measurement in extra-tympanic electrocochleography (ECochG) has been developed. The electrode consists of a silver wire 2.0 mm in diameter and 5 cm in length connected to a low noise cable. The electrode impedance values were low and the frequency characteristics were excellent. In order to explore various artifacts, the electrode was inserted into a glass cup containing 100 ml of tap water, which served as a dummy ear. A sound stimulus with an intensity of 90 dBnHL was delivered by a shielded loudspeaker located 50 cm from the dummy ear (glass cup). In this dummy test, contamination with measurable artifacts, such as electromagnetic inductions generated by a sound transducer and the CM-like mechanical vibrations which activated the dummy ear acoustically, was kept within the noise levels inherent in the recording system. The CMs were recorded from subjects with normal hearing by placing an electrode adjacent to the postero-inferior rim of the tympanic membrane (annulus tympanicus). Short tone bursts were employed as acousti stimuli and delivered by the shielded loudspeaker. CM detection thresholds were very low and CM-like responses with delayed onset time (delayed CM) were clearly observed at lower stimulus levels. The input-output curves of the CMs and delayed CMs were non-linear. These findings from the CMs did not differ from those obtained by the transtympanic needle electrode technique. Responses obtained had satisfactory S/N ratios and resulted in almost the same average calculations as those with transtympanic ECochG.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Ultrastructural alterations of hepatocytes in the tumour-bearing, cachectic rat.

Morphologic changes in the hepatocytes of tumour-bearing rats at the pre-cachectic and cachectic stages were studied by electron microscopy and were quantitatively analysed by a morphometric method. Ten male F-344 rats, subcutaneously inoculated with methylcholanthrene-induced sarcoma cells (TBR) were compared with ten pair-fed controls (CTR). There was no significant difference in the size of the cells or their nuclei, the number of mitochondria, or the number of lysosomes, between TBR and CTR at either the pre-cachectic or cachectic stage. Although the size of mitochondria of TBR was already significantly enlarged at the pre-cachectic stage, before the food intake of the TBR had decreased, the micro-structure within the mitochondria was unaltered. Marked differences were observed in the number, arrangement and distribution of the rough endoplasmic reticulum, all of which decreased significantly in TBR compared with CTR at both the pericentral and periportal zones. Changes at the periportal region were further pronounced at the cachectic stage. These results, distinct from the changes seen in simple starvation, may confirm a part of the biochemical evidence specific to tumour induced metabolic alterations.

Animals↗
PubMed1994

[Mitral valve replacement secondary to resection of mycotic cerebral aneurysm in acute phase of bacterial endocarditis--a case report].

We report a case of mitral valve replacement after ruptured mycotic aneurysm resection in acute phase of bacterial endocarditis. We have experienced a 68-year-old man with vegetation at the anterior leaflet of mitral valve and multiple systemic embolization. He underwent aneurysmectomy of ruptured mycotic cerebral aneurysm and embolectomy of left femoral artery eight days after subarachnoid hemorrhage. Mitral valve was replaced three days after successfully. If there was no heart failure preoperatively, valve replacement operation is recommended in acute phase of infected endocarditis or few days after cerebral aneurysmectomy.

Acute Disease↗
PubMed1994

Effects of tumor removal and body weight loss on insulin resistance in patients with cancer.

BACKGROUND: This study was conducted to evaluate the effects of tumor removal and body weight loss on insulin resistance. METHODS: Insulin sensitivity was examined in 12 patients with cancer and stable weight and five patients with cancer and weight loss before operation, six patients after complete tumor removal, and three normal volunteers (control) by euglycemic hyperinsulinemic glucose clamp. RESULTS: Glucose metabolized (milligrams per kilogram per minute), metabolic clearance rate of glucose (milliliters per kilogram per minute), and glucose metabolized per unit of insulin (milligrams per kilogram per minute/microunits per milligram) were significantly decreased in the cancer group compared with the control (4.50 +/- 1.32 vs 8.11 +/- 0.56 mg/kg/min, 5.26 +/- 2.22 vs 10.67 +/- 1.98 ml/kg/min, and 4.34 +/- 1.16 vs 8.92 +/- 1.03 mg/kg/min/uU/ml, respectively), regardless of the weight loss. Glucose metabolized, metabolic clearance rate of glucose, and glucose metabolized per unit of insulin ratio were significantly increased after tumor removal (3.87 +/- 0.97 vs 4.80 +/- 1.30 mg/kg/min, 4.03 +/- 1.32 vs 5.67 +/- 2.14 ml/kg/min, and 4.14 +/- 1.19 vs 5.26 +/- 1.32 mg/kg/min/uU/ml, respectively); however, increase in these values did not reach normal control levels. CONCLUSIONS: Our results would suggest that insulin resistance in patients with cancer was not caused by cancer-associated malnutrition but at least in part by tumor itself.

Adult↗
PubMed1994

[Chemotherapy-induced thrombotic occlusion of mesenteric arteries--case report and review of the literature].

We encountered two chemotherapy (CDDP and 5-FU) cases related to mesenteric thrombotic occlusion. Case 1 was a 26 yo male with adrenal carcinoma recurrence. He had been treated by CDDP and 5-FU. Five days after completion of the second course, he suffered from acute abdomen. Laparotomy revealed thrombotic occlusion of the superior mesenteric artery. Most of the small intestine and a part of the ascending colon were necrotic. Case 2 was a 60 yo female with lung and hepatic metastasis from uretal tumor. CDDP based chemotherapy was initiated. Severe abdominal pain and melena occurred one day after completion of the second course of chemotherapy. The inferior mesenteric artery was occluded and the descending colon was necrotic. Recently, a variety of chemotherapy-induced vascular lesions, including thrombotic microangiopathy, myocardial infarction and cerebral infarction, have been reported. CDDP and 5-FU were shown to be related to the acute thrombotic occlusion of the major vessels. Although the incidence is rare, the prognosis is poor. Acute vascular obstruction should be taken into consideration as a possible course of chemotherapy-related complications.

Abdomen, Acute↗