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Biomedical subjects

M Yagi

Publications and source records attributed to M Yagi.

At least 19 recordsLinked to original sources
PubMed1995

Human platelet glycoprotein V: its role in enhancing expression of the glycoprotein Ib receptor.

Platelet adhesion to an injured blood vessel wall is a critical initiating step in hemostasis mediated by a four member receptor complex (glycoprotein Ib/V/IX) interacting with plasma von Willebrand factor (vWF). The function of the GPV subunit within this complex is presently undefined. To study the role of glycoprotein (GP) V within the GPIb receptor complex, we transfected the GPV subunit gene into a hematopoietic cell line that constitutively expresses the other three subunits (human erythroleukemia [HEL] cells). Using flow cytometry, we found transfected GPV was surface expressed in HEL cells; this, in turn, led to increased surface expression of the ligand-binding GPIb alpha and GPIX subunits. Radioligand binding assays showed that GPV-transfected HEL cells bound more vWF than their non- or mock-transfected counterparts. We employed confocal microscopy of GPV-transfected HEL cells to show that GPV colocalizes with GPIb alpha on the cell surface. These findings suggest that the GPV subunit plays a role within the GPIb receptor complex by enhancing Ib alpha surface expression.

Cell Membrane↗
PubMed1995

Analgesic and hypnotic effects of subanaesthetic concentrations of xenon in human volunteers: comparison with nitrous oxide.

The purpose of this study was to examine the effects of xenon and nitrous oxide in equipotent doses of 0.3 MAC on pain threshold and auditory response time in six healthy male volunteers. Compared with 100% oxygen inhalation, xenon and nitrous oxide significantly increased the pain threshold as measured by a radiant heat algometer. There was no significant difference in analgesic effects between xenon and nitrous oxide. Xenon significantly prolonged the response time to auditory stimuli compared with 100% oxygen, but nitrous oxide did not. The inhibitory effect of xenon on the auditory response time was significantly greater than that of nitrous oxide. The same six volunteers were studied to test if naloxone antagonized analgesia induced by xenon or nitrous oxide. The analgesic effects of xenon and nitrous oxide did not differ with or without naloxone.

Adult↗
PubMed1995

Transient expression of type I collagen in glomeruli with anti-Thy-1 antibody-induced mesangial proliferative lesions.

Glomerular expression of extracellular matrices at the protein and mRNA levels was examined in rats with mesangial proliferative glomerulonephritis induced by the intravenous administration of a monoclonal anti-rat Thy-1 antibody. In close association with the mesangial proliferative lesion, type I collagen was immunostained at day 8 but not demonstrated at day 28 in the glomeruli of the kidneys. Type I collagen mRNA expression prominently increased in the nephritic glomeruli at day 4, prior to the appearance of type I collagen protein. In addition, fibronectin expression was also elevated in the diseased glomeruli at both the protein and mRNA levels. These results indicated that glomerular, probably mesangial cells, change their phenotypes during this disease, to synthesize abnormal extracellular matrices that lead to the progression of glomerular sclerosis.

Animals↗
PubMed1995

Columbin isolated from calumbae radix affects the sleeping time of anesthetized mice.

In a screening series of bioactive components in edible and medicinal plants, we found that Calumbae Radix (Colombo root, 1% powdered feed, for 5 d) and its component, columbin (20-40 mg/kg/d, for 5 d, orally), shortened the sleeping time induced by a urethane and alpha-chloralose mixture and prolonged the sleeping time induced by hexobarbital in mice.

Anesthesia↗
PubMed1995

Evaluation of long-term survivors after pancreatoduodenectomy for pancreatoduodenal carcinoma.

Long-term survivors (> or = 5 years) of pancreatoduodenal carcinoma were evaluated. The absence of retropancreatic invasion seemed to be an important factor for long-term survival in carcinoma of the pancreatic head, carcinoma of the intrapancretic bile duct confined within the bile duct wall, and stage II papilla of Vater carcinoma. The mode of infiltration was INF alpha or INF beta, with a low infiltration tendency. Lymph node metastasis, when present, was confined to the pancreatic head. It is noteworthy that two of the patients with intrapancreatic bile duct cancer had perineural infiltration to the pancreatic head plexus. In patients treated by extended resection, postoperative malnutrition and diarrhea was severe, indicating the importance of long-term nutritional management.

Aged↗
PubMed1993

Human platelet glycoprotein V: characterization of the polypeptide and the related Ib-V-IX receptor system of adhesive, leucine-rich glycoproteins.

Human platelet glycoprotein (GP) V (M(r) 83,300), whose primary structure is reported here, is a part of the Ib-V-IX system of surface glycoproteins (GPs Ib alpha, Ib beta, V, IX) that constitute the receptor for von Willebrand factor (vWf) and mediate the adhesion of platelets to injured vascular surfaces in the arterial circulation, a critical initiating event in hemostasis. System members share physical associations, leucine-rich glycoprotein (LRG) structures, and a congenital deficiency state, Bernard-Soulier syndrome. With PCR techniques and platelet cDNA templates, 1.4 kb of GP V cDNA sequence was obtained that encodes 469 GP V amino acids. A genomic 3.5-kb BamHI fragment was then isolated that includes 3.46 kb of GP V cDNA sequence: the 1.7-kb open reading frame plus 2 bases of the 5' and 1.8 kb of the 3' untranslated regions. Northern blot analysis reveals three GP V platelet transcripts of 3.8, 4.2, and 5.2 kb. A 16-amino acid signal peptide is present. Mature GP V is a 544-amino acid transmembrane protein with a 504-amino acid extracellular domain that encompasses a set of 15 tandem LRG repeats in a "flank-LRG center-flank" array [Roth, G. J. (1991) Blood 77, 5-19] along with eight putative N-linked glycosylation sites and cleavage sites for thrombin and calpain. GP V is a transmembrane, adhesive LRG protein that plays an undefined, but potentially critical, role in the expression and/or function of the Ib-V-IX receptor for vWf/shear-dependent platelet adhesion in arteries.

Amino Acid Sequence↗
PubMed1992

Alpha-fetoprotein production by hepatocellular carcinoma is prognostic of poor patient survival.

Immunohistochemistry using the avidin-biotin-peroxidase complex method was performed to study the production of alpha-fetoprotein (AFP) in hepatocellular carcinoma (HCC) tissue specimens which were obtained surgically. The relationship between staining for AFP and serum AFP levels or pathological findings was examined. The prognosis of the patients with HCC who underwent curative hepatic resections was studied with respect to the staining for AFP in their tumors. The mean serum AFP level in patients with positive AFP staining was significantly higher than in those with negative AFP staining. No significant relationship was found between AFP positivity and tumor size, tumor encapsulation, degree of vascular invasion, or the histological differentiation grade of the tumor. The patients with AFP-positive carcinomas had a poorer prognosis than did those with AFP-negative carcinomas (5-year survival rate of AFP-positive and negative groups were 26.7% and 56.5%, respectively.

Carcinoma, Hepatocellular↗
PubMed1992

An experience of cell sorting using samples isolated from paraffin-embedded tissue of neuroblastoma.

Flow cytometric DNA content analyses were performed on samples from 72 patients with neuroblastoma. Nuclear suspensions obtained from paraffin-embedded samples were prepared using the method described by Schutte et al. Determination of DNA ploidy was possible in 62 out of 72 patients. DNA diploidy was detected in 23 (37.1%) and DNA aneuploidy was found in 39 (62.9%) of these 62 patients. Cell sorting was performed on two peak areas of the DNA histogram of samples with aneuploidy. The sorted cells of the first peak area were composed of small round cells and were considered to be normal lymphocytes. The sorted cells of the second peak area were composed of relatively large cells with obvious nucleoli and were considered to be neuroblastoma cells. Thus, two cell components could be distinguished by cell sorting. It is concluded that cell sorting may be of benefit in giving detailed information about DNA histograms, even in samples obtained from paraffin-embedded tissue.

Cell Separation↗
PubMed1992

Anterior sagittal anorectoplasty for rectovestibular and anovestibular fistula.

Rectovestibular (or anovestibular) fistula is the most common form of anorectal anomaly in female infants. In the surgical repair of these malformations, anal transplantation has been in widespread conventional use. Based on the idea of posterior sagittal anorectoplasty, we devised a new approach, anterior sagittal anorectoplasty, in which, in the lithotomy position, the anterior portion of sphincter muscles are cut through a median perineal skin incision and then the rectum is pulled through the center of these muscles to make its opening at the normal position. The operation has been performed in 12 patients with satisfactory results.

Anal Canal↗
PubMed1992

Intestinal myoelectric activity and contractile motility in dogs with a reversed jejunal segment after extensive small bowel resection.

To evaluate the functioning and effectiveness of a reversed jejunal segment after extensive small bowel resection, we continuously measured the postoperative bowel motility (using bipolar electrodes and/or contractile strain gage force transducers) in interdigestive and postprandial conscious dogs at 2 to 5 weeks after surgery. The fasting duodenal migrating myoelectric (or motor) complex (MMC) occurred at markedly longer intervals in dogs with a 20-cm reversed jejunal segment created after 75% to 80% extensive small bowel resection (group 3) than in dogs that received extensive resection alone (group 2) or dogs that underwent construction of a reversed jejunal segment without bowel resection (group 1). The MMC arising from the duodenum was often interrupted at the jejunum above the proximal anastomosis and did not migrate smoothly to the reversed segment or terminal ileum in group 3. In addition, brief small discordant contractions were frequent in the reversed segment and the jejunum above the proximal anastomosis in group 3. The duration of the postprandial period without duodenal MMC activity was significantly prolonged in groups 2 and 3. These results suggest that the transit time and passage of intestinal contents were delayed and that the periodical MMC was disturbed in group 3. The delay of transit time was due to prolongation of the interval between duodenal MMCs, the interruption of MMC propagation at the jejunum above the proximal anastomosis, the dominance of MMCs that followed the inherent anatomical continuity of the bowel, and discordant movements across the proximal anastomosis. Functional obstruction could be a potential problem in a 20-cm reversed jejunal segment inserted after extensive small bowel resection.

Anastomosis, Surgical↗
PubMed1992

Sensorineural hearing loss associated with otitis media with effusion.

The clinical records of 1,372 cases of otitis media with effusion (OME) treated during the past 10 years were reviewed in search of associations with sensorineural hearing loss (SNHL). In 14 cases (1.0%), the development of SNHL was considered to be etiologically related to OME. These 14 cases were classified into two groups. In group A, which consisted of 5 cases, the clinical feature was acute onset of SNHL and gradual improvement. In group B of 9 cases, SNHL progressed gradually or insidiously and did not improve. Different pathophysiology may be assumed to underlie these two groups. The results of this study demonstrate that we have to pay attention to a possible development of SNHL during the course of OME.

Acute Disease↗
PubMed1992

Studies on the constituents of edible and medicinal plants. III. Effects of seven limonoids on the sleeping time induced in mice by anesthetics.

Effects of seven limonoids, obakunone (1), 7 alpha-obakunol (2), 7 beta-obakunol (3), limonin (4), 7 alpha-limonol (5), 7 beta-limonol (6) and nomilin (7), on the sleeping time induced in mice by anesthetics were assayed. All the limonoids, except for 2, shortened the sleeping time induced by alpha-chloralose and urethane. 7 gave the highest reduction rate of sleeping time, and the order of the reduction rate of sleeping time was as follows; 7 > 1 and 3 > 4, 5 and 6. As the chemical structures of these compounds are similar to each other, the relationship between the structure and the effects of limonoids on sleeping time was discussed.

Animals↗
PubMed1992

Protective effects of antioxidants on paraquat-induced acute renal failure in mice.

The protective effects of antioxidants against elevated blood urea nitrogen (BUN) were studied in newly developed acute renal failure in mice induced by paraquat. The administration of paraquat caused marked azotemia accompanied by a decreased glomerular filtration rate. In contrast, elevated BUN was significantly reduced by the preadministration of either dimethylthiourea, deferoxamine or alpha-tocopherol. These data suggest that acute renal failure induced by paraquat is mainly related to the hydroxyl radicals produced via the iron-catalyzed Haber-Weiss reaction.

Acute Kidney Injury↗
PubMed1992

[Prognosis of acute low-tone sensorineural hearing loss].

We studied 50 patients with acute low-tone sensorineural hearing loss (ALHL) who were examined at the Department of Otolaryngology, University of Tokyo, and followed up for 18 months or more. We investigated the prognosis of hearing loss within 3 months after onset, rate of recurrence during long-term follow-up, interval between the first and the second episodes of hearing loss or between onset and the time when the diagnosis of Meniere's disease was made, and factors affecting prognosis. The results were as follows. 1. Within the initial 3 months of follow-up, hearing loss continued to fluctuate in 5 patients. In the remaining 45, hearing returned to normal in 34, improved without returning to normal in 6, showed no marked change in 4, and became worse in one. 2. In long-term follow-up, the recurrence of hearing loss without vertigo occurred in 16 patients, and 5 others were eventually diagnosed as having Meniere's disease. The average interval between the first and second episodes of hearing loss was 9.2 months, and the diagnosis of Meniere's disease was made an average of 27 months after onset. 3. Recurrence was not significantly related to the initial prognosis of hearing loss. 4. Within the initial 3 months of follow-up, the prognosis of hearing loss was significantly better in patients whose hearing loss at 1 kHz was within 20 dB, and tended to be better in females and in patients attending within one week of onset. Long-term follow-up showed that the rate of recurrence was significantly lower in patients aged 40 years or more, and tended to be lower in patients who visited the hospital within one week of onset or whose hearing loss at 1 kHz was within 20 dB. 5. There were no significant differences between patients with single and recurrent attacks with respect to sex, subjective symptoms, and results of the glycerol test and electrocochleography. ALHL tends to recur without any relationship to the initial prognosis of hearing loss. Since it is still difficult to predict whether or not hearing loss will recur, long-term follow-up is necessary even in patients with good initial prognosis.

Acute Disease↗
PubMed1992

[A temporal bone study of the jugular fossa].

This study was performed to elucidate the anatomic variations of the jugular fossa (JF) on the basis of examination of 120 human temporal bones. Observations were made of temporal bones sectioned along a plane including the cochlea, the JF, and long axis of the internal auditory canal. The position of the upper margin of the JF was classified according to its relation to the tympanic cavity, the cochlea, and the internal auditory canal. The height of the upper margin of the JF was classified as follows. Low type; inferior to the level of the external auditory canal. Middle type; between the level of the external auditory canal and the cochlea. High type; superior to the level of the cochlea. The results revealed that 58 ears were of low type, 46 middle type, and 16 high type. Middle and high type comprised 62 ears, thus in 52% of ears the upper margin of the JF was situated superior to the external auditory canal. The relation between the JF and the cochlea was classified as follows. Medial type; medial to the medial margin of the cochlea. Lateral type; lateral to the medial margin of the cochlea. The results showed that 74 ears were of medial type, and 46 lateral type. Therefore, in 62% of ears the upper margin of the JF was situated medial to the medial margin of the cochlea. Forty-seven ears of medial type were of middle or high type. Ears of lateral type included none of high type. The jugular bulb diverticulum was observed in 32 ears, which consisted of 3 of low type, 13 middle type, 16 high type. When the upper margin of the JF was positioned higher, the JF was in a more medial position. However, no defect of the bony labyrinth was observed. In conclusion, it is considered that protrusion of the jugular bulb into the tympanic cavity was not caused by the abnormally high position of the JF, but by its lateral displacement. Distances from the JF to the surrounding structures were as follows; to the tympanic membrane 5.58 +/- 2.43mm (mean +/- S.D.), to the tympanic cavity 2.94 +/- 1.92mm, to the cochlea 4.93 +/- 2.20mm, and the internal auditory canal 5.82 +/- 2.38mm.

Adult↗