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Biomedical subjects

T Shoji

Publications and source records attributed to T Shoji.

At least 235 records · Page 13Linked to original sources
PubMed1992

[A case of paraesophageal bronchogenic cyst with esophageal communication].

A case of mediastinal bronchogenic cyst communicating with the esophagus was reported. Previously, only 2 cases have been reported in the available literature. A 34-year-old man was admitted with a cystic mass communicating with the esophagus which was demonstrated on a barium study. Operation was performed with a suspect of esophageal diverticulum or congenital cyst with esophageal communication. At right thoracotomy, a mass measuring 6.0 x 5.0 cm with a well-defined patent communication to the esophagus was resected. It was a monolocular cyst containing a small amount of viscous mucus. Histologically, the cyst lined by a ciliated columnar epithelium, and it was diagnosed as a bronchogenic cyst because of the presence of the mucous glands, smooth muscle tissue and cartilage. This is the first case report of mediastinal bronchogenic cyst with esophageal communication appeared in the Japanese literature.

Adult↗
PubMed1992

[Regulation of the cultured mouse parenchymal liver cells (P-LC) by mast cells].

Mast cells suppressed the proliferation of parenchymal liver cells (P-LC) in a dose-dependent manner, when they were cocultured with P-LC. On the contrary, mast cells activated by IgE and anti-IgE enhanced DNA synthesis of P-LC dose-dependently. The activity enhancing the proliferation of P-LC was found in the supernatant of the activated mast cells, but not in that of untreated mast cells, suggesting the secretion of active factors by active mast cells. Histamine, which are released by the activated mast cells, suppressed the enhancement of P-LC proliferation by activated mast cells. Since histamine and heparin did not effect the proliferation of P-LC directly, histamine may bring the suppression through regulating the activated mast cell. On the basis of these findings, we discuss the role of mast cells in liver regeneration.

Animals↗
PubMed1991

Comparison of the effects of endothelin-1 and Bay k 8644 on twitch contractions of the field-stimulated rat vas deferens.

Endothelin-1 (ET-1) potentiated both the fast and the slow components of the twitches of the isolated field-stimulated rat vas deferens, whereas Bay k 8644 potentiated only the fast component. Nicardipine tended to decrease the potentiation. ET-1, but not Bay k 8644, caused membrane depolarization and resting tension elevation, which were suppressed by nicardipine. The excitatory junction potentials (EJPs) were augmented by Bay k 8644 and the effect was not changed by nicardipine. ET-1, however, apparently did not augment the EJPs, because of the accompanying depolarization. These results indicate a difference in mechanism of the potentiating effects of ET-1 and Bay k 8644.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

Comparison of the effects of endothelin and Bay k 8644 on cardiohemodynamics in anesthetized pigs.

The effects of endothelin on cardiohemodynamics in anesthetized open-chest pigs were compared with those of the Ca2+ channel agonist Bay k 8644. I.v. administration of endothelin (0.1-1 microgram/kg) dose relatedly decreased coronary blood flow velocity (CFV), cardiac output, the maximal rate of rise in left ventricular pressure (LV dP/dtmax) and heart rate, and increased systolic and diastolic blood pressure and systemic vascular resistance. Bay k 8644 (0.1-30 micrograms/kg) showed similar effects on cardiohemodynamics, except that it caused a substantial increase in LV dP/dtmax and did not change stroke volume. I.c. administration of endothelin (0.1-1 microgram) into the left circumflex coronary artery (LCX) produced a dose-dependent and sustained decrease in CFV followed by a marked increase in the ST segment of epicardial electrocardiograms and a depression in myocardial shortening in the region supplied by LCX. An increase in left ventricular end-diastolic pressure and a reduction in LV dP/dtmax were also observed after endothelin. In contrast, Bay k 8644 caused a transient decrease in CFV and an increase in LV dP/dtmax, without causing any changes indicative of myocardial ischemia. Although the reduction in CFV after i.c. endothelin was not affected by i.v. infusion of nicardipine (1 microgram/kg per min), the reduction in CFV observed after i.c. Bay k 8644 was significantly suppressed (P less than 0.05). We conclude that endothelin is a more potent coronary vasoconstrictor than Bay k 8644 and provokes marked myocardial ischemia.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

Roles of hypoalbuminemia and lipoprotein lipase on hyperlipoproteinemia in continuous ambulatory peritoneal dialysis.

To assess the mechanism of serum lipoprotein abnormalities in continuous ambulatory peritoneal dialysis (CAPD), we measured serum lipids, apolipoproteins, and postheparin lipases in 46 patients with end-stage renal disease (ESRD) treated on CAPD, 26 patients on hemodialysis (HD), and 29 healthy subjects. HD patients had higher serum triglyceride levels than the healthy controls, showing type IV and type III phenotypes. They had significantly lower activities of hepatic triglyceride lipase (HTGL) in postheparin plasma compared with controls, and postheparin lipoprotein lipase (LPL) was also decreased by 15%, although the latter change was not statistically significant. CAPD patients had elevated levels in triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and apolipoprotein (apo) B, showing type IV, III, and II (IIb and IIa) phenotypes. The mean LPL and HTGL activities in CAPD patients were not different from those of HD patients. CAPD patients with hyperlipoproteinemia had significantly higher serum albumin levels than those with normolipidemia. There was a significant positive correlation between albumin and apo B levels in CAPD patients. In hyperlipidemic CAPD patients, there was no difference in serum albumin concentrations or HTGL activities among lipoprotein phenotypes, whereas LPL activities were significantly higher in the patients with type II than those with type IV hyperlipoproteinemia. These results suggest that there was some linkage between alterations in serum albumin and lipoproteins, and that LPL was related to phenotypic variation of hyperlipoproteinemia in CAPD.

Apolipoproteins↗
PubMed1991

Telescience testbed in human space physiology.

The present telescience testbed study was conducted to evaluate the feasibility of physiological experimentation under restricted conditions such as during simulated weightlessness induced by using a water immersion facility, a reduced capacity of laboratory facilities, a delay and desynchronization of communication between investigator and operator, restrictions of different kinds of experiments practiced by only one operator following a limited time line and so on. The three day's experiments were carried out following the same protocols. The operators were changed every day, but was the same the first and the third day. The operators were both medical doctors but not all round experts in the physiological experimentation. The experimental objectives were: 1) ECG changes by changing water immersion levels, 2) blood pressure changes, 3) ultrasonic Echo-cardiographic changes, 4) laser Doppler skin blood flowmetry in a finger, 5) blood sampling to examine blood electrolytic and humoral changes. The effectiveness of the testbed experiment was assessed by evaluating the quality of the obtained data and estimating the friendliness of the operation of the telescience to investigators and operators.

Aerospace Medicine↗
PubMed1991

Change of lipid peroxide levels in rat tissues after cisplatin administration.

cis-Diamminedichloroplatinum(II) (cisplatin) is one of the most effective antitumor agents currently available for cancer chemotherapy. Unfortunately, its clinical use is severely limited by its dose-dependent nephrotoxicity. Recently, it has been reported that this nephrotoxicity is associated with an increase in lipid peroxides in the rat kidney. However, it is not clear if the specific nephrotoxicity is related to the increase in lipid peroxides induced by cisplatin since the increase in lipid peroxides in the kidney has not been compared with that in other tissues. We examined the changes in lipid peroxide levels in rat tissues after cisplatin administration to clarify the relationship between lipid peroxides and cisplatin nephrotoxicity. After cisplatin administration (5 mg/kg i.p.), the relative weight of the rat liver decreased, but that of the kidney increased. The increase in lipid peroxide levels in the kidney and liver of cisplatin-treated rats was significant. The percent change from control was greatest in the kidney on the 5th day after administration among all tissues examined. Cisplatin did not affect enzymatic or non-enzymatic lipid peroxidation in microsomes of rat kidney or liver in vitro. It appears that the increase in lipid peroxides in the kidney was not a direct consequence of cisplatin administration.

Animals↗
PubMed1991

Sensitivity and transduction mechanisms of responses to general odorants in turtle vomeronasal system.

(a) The responses of the vomeronasal organ to general odorants in the turtle, Geoclemys reevesii, were measured by recording the accessory olfactory bulbar responses. The threshold concentrations of the vomeronasal responses to various odorants were similar to those in main olfactory bulbar responses, indicating that vomeronasal cells lacking cilia and olfactory cells having many cilia have similar sensitivities to general odorants. (b) The vomeronasal epithelium was perfused with 100 mM NaCl solution and the salt-free solution and the effects of NaCl on the vomeronasal responses to various odorants were examined. There was no essential difference between the concentration-response curves for n-amyl acetate and menthone dissolved in 100 mM NaCl solution and those dissolved in the salt-free solution in the whole concentration range examined. The ratios of the magnitudes of vomeronasal responses in the salt-free solution to those in 100 mM NaCl solution were between 1.01 and 1.10 for seven odorants tested. (c) The magnitudes of responses to the odorants were unchanged by changes in NaCl concentrations. The replacement of Na+ with organic cations such as choline+, Bis-Tris propane2+, and N-acetyl-D-glucosamine+ did not affect the magnitudes of the responses to the odorants. The Na channel blocker amiloride also did not affect the responses. (d) The vomeronasal responses were practically unchanged by changes in CaCl2 concentration. The Ca channel blockers diltiazem and verapamil did not affect the responses. (e) The replacement of Cl- with SO4(2-) did not affect the magnitudes of the vomeronasal responses. (f) The present results suggest that ion transport across the apical membranes of vomeronasal receptor cells does not contribute to the responses to odorants in the turtle.

Amiloride↗
PubMed1991

Effects of cromakalim on renal hemodynamics and function in dogs: comparison with nicardipine.

The effects of cromakalin, a potassium channel opener, on renal hemodynamics and renal function were investigated in pentobarbital-anesthetized dogs. Intrarenal infusion of cromakalim at 0.5 micrograms/kg/min resulted in significant increases in renal blood flow (RBF), glomerular filtration rate (GFR), urine flow, and renin release. The urinary excretion rate of sodium increased by the same proportion as that of calcium. Free water reabsorption rate/osmolar clearance did not significantly change throughout the experiments. These data suggest that cromakalim did not inhibit sodium transport at the medullary portion of the ascending limb of Henle's loop and may have increased the delivery of sodium to Henle's loop. Intrarenal infusion of nicardipine increased RBF, GFR, urine flow, and the urinary excretion of electrolytes (Na, K, and Ca). The renal effects of cromakalim were very similar to those of nicardipine. Cromakalim was superimposed on a nicardipine infusion of a maximal effective dose. Superimposition of cromakalim to the nicardipine infusion did not cause any additional changes in renal hemodynamics and renal function. These data suggest that cromakalim and nicardipine exert their effects on renal hemodynamics and function via the same pathway.

Animals↗
PubMed1991

Effects of a new nitro compound on the systemic circulatory system in dogs.

The present study was undertaken to evaluate the effects of a newly synthesized nitro compound (E-4701) on the systemic circulatory system with special reference to venous return and vascular compliance. Dogs were anesthetized with sodium pentobarbital. After opening the chest, cannulae were inserted into the superior and inferior vena cavae and into the right atrial appendage. The venous flow from the caval veins was redirected to a blood reservoir with an outlet at a constant height. The blood was pumped into the right atrium at a constant flow rate. E-4701 had a hypotensive effect, and also caused a decrease in reservoir blood volume; i.e., a decrease in venous return. Venous return via the superior vena cava was increased, whereas return via the inferior vena cava was decreased. Similar effects on the systemic circulatory system were observed with nitroprusside. The lowest dose of nitroprusside that caused a significant reduction in blood pressure was the same dose as that which caused a decrease in reservoir blood volume. However, a low dose of E-4701 caused a significant reduction in reservoir blood volume without affecting the systemic blood pressure. Arterial and venous compliances were increased by both E-4701 and nitroprusside. Nitroglycerin and isosorbide dinitrate increased venous compliance, but did not affect arterial compliance. The results suggest that E-4701 caused an almost equipotent reduction in blood pressure and venous return by dilating the arterial and venous vascular beds. The capacitance vessels may be more sensitive to E-4701 than the resistance vessels.

Animals↗
PubMed1991

Uremic serum contains humoral factor(s) larger than fifty kilodaltons which suppresses endothelin production in cultured endothelial cells.

Direct effects of human uremic serum on the production of endothelin-1 in cultured porcine endothelial cells were examined in this study. Uremic serum decreased the level of monomeric endothelin-1 secreted into the culture medium by endothelial cells. This effect occurred at a transcriptional step because uremic serum decreased the endothelin-1 mRNA level in those cells. For the partial characterization of this inhibitory activity, uremic serum was fractionated with a centricut column. Uremic serum contains humoral factor(s) larger than 50 kD which suppress the endothelin-1 mRNA level in cultured endothelial cells.

Animals↗
PubMed1991

Medical vs surgical treatment of acute aortic dissection in an intensive care unit.

To determine which therapeutic procedure is most appropriate for which type of aortic dissection, we investigated 146 cases of acute aortic dissection. In the group with dissection of the ascending aorta, 58.6% of patients given medical therapy and 48.8% of patients given surgical therapy died. In the group with dissection of the descending aorta, 14.0% given medical therapy and 50.0% given surgical therapy died. High mortality in the medical group with type A dissection was caused by delayed operation. Better survival was achieved in treated than surgically treated patients with acute distal dissection. In patients with cardiac tamponade, aortic regurgitation, hemothorax/hemo-mediastinum, visceral ischemia and peripheral ischemia, mortalities following medical treatment were fairly high. Surgical treatment brought on improvement in mortality in these groups. However, in the cases complicated by renal dysfunction, the mortality in the surgical group was higher than that in the medical group. 42 patients (28.8%) had no evidence of any complication and only 6 (14.3%) died. In 20 cases (47.6%) of uncomplicated dissection, no blood flow was observed in the false lumen. In cases with open false lumen, the following abnormal findings were more conspicuous: thrombocytopenia, decreased level of fibrinogen, increased fibrin degradation product and soluble fibrin monomer complex. However, these changes seem to be minimal in cases with thrombosed false lumen. The measurement of coagulation factors may be one useful method to determine which therapeutic procedure is most suitable.

Acute Disease↗
PubMed1991

Forskolin preferentially dilates the afferent arteriole in the canine kidney.

Intrarenal infusion of forskolin (0.2 microgram/kg/min) in anesthetized dogs increased renal blood flow (RBF) and glomerular filtration rate (GFR) to the same degree but did not change the mean arterial pressure or heart rate. Forskolin also increased urine flow and urinary sodium excretion. The proportional increases in RBF and GFR may result from a preferential action of forskolin to dilate the afferent arteriole.

Adenylyl Cyclases↗