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Biomedical subjects

Y Yokoi

Publications and source records attributed to Y Yokoi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Distribution of thyrotropin releasing hormone receptor in rats: an immunohistochemical study.

Thyrotropin releasing hormone (TRH) receptor was identified immunohistochemically in the rat tissues using anti-peptide antiserum. Anti-TRH receptor antiserum was raised in New Zealand white rabbits immunized with a conjugate of synthetic TRH-receptor peptide (15-28) to bovine serum albumin. Immunohistochemical analysis was performed by the avidin-biotin complex method. TRH-receptor immunoreactivity was visualized in the central nervous system and anterior pituitary thus supporting previous investigations of TRH receptor distribution using in vitro autoradiographic ligand binding. Significant stain was detected in neural perikarya, axons and dendrites as well as in many cells of the retina, adrenal medulla, stomach mucosa, Auerbach's nervous branch and Mysner's nervous branch of the stomach, small intestine and colon. When using antiserum preincubated with synthetic TRH-receptor peptide (15-28) or rat anterior pituitary homogenate which contains TRH-receptor peptide, no significant stain of the anterior pituitary cells or neurons in the hypothalamus was detected. These findings suggest that TRH-receptor is widely distributed and that this method is valuable in studying the distribution of TRH-receptor in rats.

Journal Article↗
PubMed1995

Distribution of somatostatin receptor type 1 in the rat. An immunohistochemical study.

Somatostatin receptor type 1 (SSTR-1) was identified immunohistochemically in the rat tissues using anti-peptide antiserum. Anti-somatostatin receptor antiserum was raised in New Zealand white rabbits immunized with a conjugate of synthetic SSTR-1 peptide (41-52) with bovine serum albumin. Immunohistochemical analysis was performed by the ABC method. SSTR-1 immunoreactivity was visualized in the central nervous system, anterior pituitary, mucosa of stomach and duodenum, Auerbach's nervous branch and Mysner's nervous branch of gastrointestinal tract and pancreas. Significant staining was detected in neural perikarya, axon and dendrite. When using antiserum preincubated with synthetic SSTR-1 peptide (41-52) or rat anterior pituitary homogenated which contains SSTR-1, no significantly stained anterior pituitary cells or neurons in the hypothalamus were detected. These findings suggest that SSTR-1 is widely distributed and that this method is valuable in studying the distribution of somatostatin receptor in rats.

Journal Article↗
PubMed1994

The role of endothelin in the pathophysiology of renal impairment during acute liver rejection.

We assessed the role of endothelin in the development of renal dysfunction during acute rejection by examining the effect of a selective endothelin A (ETA) receptor antagonist BQ-123 in rats with acute liver rejection. Serum endothelin levels and endogenous creatinine clearance (Ccr) were monitored on days 1, 3, 5, 7, and 9 postoperatively. As indicators of renal hemodynamics, the estimated hemoglobin concentration of renal tissue (IHb) and the oxygen saturation of hemoglobin in renal blood (ISO2) were determined by reflectance spectrophotometry. In addition, the clearance of inulin and P-aminohippurate were determined, and the renal tissue blood flow was estimated by laser-Doppler flowmetry (LDF). As a model of allograft rejection, Lewis rats were transplanted orthotopically with DA rat livers. The serum endothelin level of allografted rejectors was significantly (P < 0.05) higher than that of isografted controls (Lewis rats with Lewis livers) on postoperative day 5, and it increased to a maximum of 5.38 +/- 0.95 pg/ml on day 9 (versus 1.23 +/- 0.18 pg/ml preoperatively). The values of Ccr, IHb, and ISO2 were all significantly (P < 0.05) lower in allografted rejectors than in isografted controls on day 5, and subsequently declined to a minimum on day 9 (P < 0.01). Treatment of allografted rejectors with BQ-123 markedly improved the renal parameters to levels similar to those in the isografted controls. These results strongly suggest that endogenous endothelin may play an important role in the development of renal impairment during acute liver rejection by reducing renal blood flow through binding with ETA receptor.

Acute Disease↗
PubMed1994

Hepatopancreatoduodenectomy for advanced gallbladder carcinoma.

OBJECTIVE: To assess the effectiveness of hepatopancreatoduodenectomy (HPD) in patients with advanced gallbladder carcinoma directly invading the liver and pancreas, generally considered to be nonresectable. PATIENTS AND METHODS: Sixty patients with gallbladder carcinoma admitted to our hospital from 1978 to 1992, of whom 55 had Nevin stage V carcinoma and 21 had resectable tumors. Of these patients, seven underwent HPD. The remaining 34 patients had nonresectable tumors. The outcomes of patients undergoing HPD and those with nonresectable tumors were compared and the effect on their quality of life was also analyzed. RESULTS: Postoperative complications occurred in five of the seven patients after HPD, but there were no operative deaths. The 1- and 2-year survival rates were 57% and 28.6%, respectively, with a median survival time of 12 months. In contrast, the 1- and 2-year survival rates of the 34 patients with nonresectable tumors were both 5.8%, and the median survival time was 2 months. The median and mean durations of home stay after HPD were 6 and 10.5 months, respectively. CONCLUSION: Hepatopancreatoduodenectomy has the potential to improve both survival and the quality of life for carefully selected patients with advanced gallbladder carcinoma.

Adult↗
PubMed1994

Functional abnormalities of sinusoidal endothelial cells in rats with acute liver rejection.

The purpose of this study was to determine the changes of hepatic sinusoidal endothelial cell (SEC) function in acute liver rejection with respect to receptor-mediated endocytosis. Orthotopic rat liver transplantation was performed in Lewis rats grafted with DA livers and in Lewis rats grafted with Lewis livers as rejectors and controls, respectively. Animals were killed at 1, 3, 5, 7, and 10 days after the operation. Fc receptors (FcRs) were histochemically stained on frozen liver sections by applying peroxidase-antiperoxidase IgG complex as a ligand, and the FcR activity, i.e., capacity of binding the ligands represented by the FcR staining intensity, was semiquantitatively analyzed as an indicator of SEC function. The serum level of hyaluronic acid, which is specifically cleared from the circulation by receptor-mediated SEC endocytosis, was also assayed, along with the total serum bilirubin. Three days after the operation, the SECs of rejectors showed a significantly weaker FcR staining intensity of about half the value of that seen in the controls (P < 0.05), and staining disappeared after 5 days (P < 0.01). The decrease of FcR staining intensity, i.e., FcR activity, showed a correlation with elevation of the serum hyaluronic acid level (r = -0.77; P < 0.001). Histological evidence of endothelialitis and a significant elevation of total serum bilirubin (P < 0.01) were also present at 3 and 5 days, respectively. These results suggest that impairment of the endocytic function of SECs occurs at an earlier phase of acute liver rejection when compared with development of abnormalities of traditional indicators. Determination of receptor-mediated SEC endocytic functions may thus provide useful information for the early diagnosis of acute rejection.

Animals↗
PubMed1994

[Spectrophotometric determination of uric acid in serum using a titanium (IV)-porphyrin complex].

Aqueous solution of oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium (IV) complex, a Ti-TPyP reagent, was found to be very useful for the spectrophotometric determination of hydrogen peroxide. The reagent (lambda max 432 nm) reacts with hydrogen peroxide to form a monoperoxocomplex, resulting in a significant decrease of the absorbance at 432 nm. The decrease (delta A) in absorbance was proportional to the concentration of hydrogen peroxide. The Ti-TPyP reagent was successfully applied to the assay of uric acid in the serum, using uricase to produce hydrogen peroxide through enzymatic oxidation. Using only 5 microliters serum, a linear relationship was obtained between delta A and uric acid concentration in the serum ranging from 5 x 10(-6) to 1 x 10(-3) M. The apparent molar delta A of uric acid was 2.2 x 10(5) M-1 cm-1. The relative standard deviation of repeated runs (n = 8) was 2.8% at 3.77 x 10(-4) M uric acid. The analytical recovery of uric acid (5 x 10(-4) M) added to the serum was 96.8 to 105.0%. No pre-concentration and deproteinization were required to determine uric acid in the serum by the present method because of the high sensitivity and selectivity of the Ti-TPyP reagent for hydrogen peroxide.

Gout↗
PubMed1993

[A case of asymptomatic common carotid artery occlusion with the persistent proatlantal intersegmental artery].

A case of asymptomatic common carotid artery occlusion with direct vertebrocarotid anastomosis (proatlantal intersegmental artery) in a 70-year-old male is reported. Despite the acquired left common carotid artery occlusion, there was no demonstrable neurologic deficits that would occur by the involvement of the area supplied by the occluded carotid system. Cerebral angiography revealed, in addition to efficient collateral circulation from the contralateral carotid system through the anterior communicating artery, a collateral channel from the left vertebral artery to the ipsilateral external carotid artery via the proatlantal intersegmental artery. These collateral circulations were indicated to be important in prevention of possible grave neurologic consequences. The proatlantal intersegmental artery, though rarely visualized by ordinary cerebral angiographic procedures, was thus demonstrated to be capable of serving as a collateral channel of potential usefulness in the event of severe intracranial hemodynamic alterations, including acquired common carotid artery occlusion.

Aged↗