Search PubMed⌕ Search

Biomedical subjects

A Takabayashi

Publications and source records attributed to A Takabayashi.

At least 55 records · Page 3Linked to original sources
PubMed1996

Evidence of sensory conflict and recovery in carp exposed to prolonged weightlessness.

BACKGROUND: Evidence in support of the sensory conflict hypothesis for space motion sickness (SMS) is still needed. HYPOTHESIS: We hypothesized that sensory conflict and recovery processes should be demonstrated in intact fish during initial days of microgravity exposure, as a disturbance and restoration of the dorsal light response (DLR; a functional model of visual-graviceptor interaction), respectively. We also expected that this would be true in an otolith-removed fish if it had been fully compensated for dysfunction before the exposure. METHODS: The DLR of carp (Cyprinus carpio) was examined intermittently during the 8-d mission of Spacelab-J. Two carp, normal and labyrinthectomized (LB), made the flight. RESULTS: In the normal carp, the DLR was unstable for the first 3 d inflight but gradually recovered thereafter. The recovery was characterized by gradual restoration of the DLR tilt speed. The LB fish whose otoliths had been removed 2 mo before the flight maintained DLR at the first inflight test session (22 h after launch), but DLR was disrupted at 2 d as in normal fish. The recovery process could not be evaluated in this fish, because the EEG cable which was attached to the fish for supplementary study became tightly twisted and thus immobilized the fish for the remainder of the experiment. CONCLUSION: These findings provided additional evidence in fish for sensory-motor disorder and readjustment during the early phase of microgravity, thus supporting the sensory conflict hypothesis for SMS.

Animals↗
PubMed1995

Recurrent splenic artery aneurysms developing after aneurysmectomy without splenectomy: report of a case.

We report herein the case of a 47-year-old man who developed a huge splenic artery aneurysm (SAA) with splenomegaly, for which ligation of the splenic artery and partial aneurysmectomy was performed. A celiac arteriogram taken 2 months postoperatively revealed that two small aneurysms had developed in the collateral vessels, indicating that increased blood flow through the collateral circulation could be responsible for the formation of secondary aneurysms. This postoperative change suggests that the etiology is related to the SAA and thus, the possibility that aneurysms may develop in the collateral vessels following spleen-preserving procedures for SAA must be borne in mind and careful follow-up performed at regular intervals.

Aneurysm↗
PubMed1995

The ratio of reduced glutathione/oxidized glutathione is maintained in the liver during short-term hepatic hypoxia.

Controversy persists as to whether reperfusion-induced injuries actually occur in the hepatocyte. The liver is the major source of glutathione, a scavenger of hydrogen peroxide. The aim of this study was to evaluate the sensitivity of the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) [GSH:GSSG] as an index of hepatic metabolic stress. A total of 121 rats were studied. The superior mesenteric vein (SMV) was occluded for 30 min, and this was followed by 0, 10, or 120 min of reperfusion. Total glutathione and GSSG levels in the liver, bile, and plasma were quantified, using glutathione reductase-coupled enzymatic assays. Results indicated that the hepatic GSH/GSSG ratio was maintained after an occlusion of the SMV, despite a decrease in adenosine triphosphate (ATP) level and energy charge potential. However, plasma levels of total glutathione and GSSG in the inferior vena cava increased after SMV occlusion and continued to increase after reperfusion. Biliary GSSG efflux decreased during 30-min occlusion of the SMV, and remained low even after reperfusion. The liver maintains homeostasis despite a decrease in biliary GSSG efflux, probably by secreting excess GSSG into the hepatic vein when the SMV is occluded. We conclude that the total amount of glutathione and GSSG in the plasma is directly correlated with oxidative stress in the liver.

Animals↗
PubMed1995

The looping behavior of fish in microgravity.

Fish subjected to microgravity during space flight were monitored for their swimming behavior, particularly the looping response. Experiments were performed on normal fish, unilaterally labyrinthectomized fish, and bilaterally labyrinthectomized fish. Observation were compared against the behavior of other species which had been evaluated in microgravity during parabolic flight.

Animals↗
PubMed1995

Biliary haptoglobin, a potent promoter of cholesterol crystallization at physiological concentrations.

BACKGROUND/AIMS: Several proteins present in human bile have been reported to promote cholesterol crystallization and thus are potentially important in the formation of cholesterol crystals as the initial stage in gallstone pathogenesis. To be physiologically relevant, such proteins must either be present in high concentration in bile or have a potent promoting activity. The current study explored several of the more abundant but unexamined biliary proteins based upon their also having sufficiently high serum concentrations that antibodies were available for both their isolation and quantitation. METHODS: Protein purification was accomplished by immunoaffinity chromatography of bile followed by delipidation. Con A affinity chromatography of bile was used to obtain the bound fraction, a portion of which was delipidated. Crystallization-promoting activity of both the purified proteins and Con A-bound glycoprotein fractions (CABG) was measured by a photometric crystal growth assay. A competitive antibody-capture ELISA assay was developed to measure concentrations of alpha 1-antitrypsin, transferrin, and haptoglobin in native bile. RESULTS: At their relevant physiological concentrations, biliary haptoglobin (15 micrograms/ml) had a crystallization-promoting activity twice that of the biliary IgM (75 micrograms/ml) used as a reference standard (P < 0.05). Biliary transferrin (20 micrograms/ml) had only modest promoting activity (P < 0.05). Biliary alpha 1-antitrypsin (50 micrograms/ml), by contrast, showed no promoting activity. Delipidation of the CABG fraction decreased its promoting activity by 75%. Biliary haptoglobin accounts for about 30% of delipidated total CABG-promoting activity. CONCLUSIONS: Biliary haptoglobin at its physiological concentration has a highly potent crystallization-promoting activity and thus becomes a candidate for major attention in understanding gallstone pathogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Specificity↗
PubMed1994

Complete obstruction of the inferior vena cava due to chronic relapsing pancreatitis: a case report.

A woman aged 62 with long history of chronic relapsing pancreatitis presented with swelling and ulcer in the lower limbs and occasional gastrointestinal bleeding. The radiological imaging showed complete obstruction of Inferior Vena Cava (IVC) at the level of the pancreas and well developed collateral vessels. Portal vein and splenic vein were also obstructed and superior mesenteric venous blood drained into the liver via coronary vein. She was originally found to have pancreas head tumor, which was not resectable. A palliative operation was performed, but histological examination of pancreatic specimen suggested only chronic inflammation and no evidence of malignancy. She was diagnosed as tumor-forming type chronic pancreatitis. Although SPV or SMV-PV obstruction has been recognized as a complication of chronic pancreatitis, IVC obstruction can occur by the same mechanism. This is the only case but one ever reported. Not only splenoportography but IVC-graphy will contribute to more precise understanding of patient's condition with chronic pancreatitis.

Chronic Disease↗
PubMed1994

Space experiment using large-sized fish: in case of carp in Spacelab-J mission.

Two carp of 26 cm in size, intact and otolith-removed (LB), were flown on the Spacelab-J for 8 days in September 12-20, 1992. Light-dependent reaction to alternating direction of illumination was recorded for 10 min twice a day together with the cerebellar EEG activity, on 2 days before the launch, during the flight and for 4 days after the landing, in same fish chamber. Reproducing the video image, it was revealed that both carp were healthy during the mission, but the LB fish was almost immobilized from the 3rd test session (48 hours in flight) by tight twisting of the EEG cable. Both fish after landing tended to stay still on the bottom of the fish chamber. Findings that the body weight reduced remarkably in both fish and that nitrite and nitrate levels of the fish water were usually high, suggested that the fish metabolism might have been enhanced during the flight.

Animals↗
PubMed1993

Isolation of a human biliary glycoprotein inhibitor of cholesterol crystallization.

BACKGROUND: About 50% of populations in developed countries have bile supersaturated with cholesterol, which is a major risk factor for cholesterol gallstone formation. Despite the prevalence of supersaturated bile, only about 10% of these populations develop gallstones. The existence of a biliary protein that inhibits cholesterol crystallization was hypothesized to explain this discrepancy. This report outlines the purification and characterization of such a human biliary glycoprotein. METHODS: Chromatographic methods were used for separation and characterization. Additional steps included activity analysis by crystal growth assay, electrophoresis, and deglycosylation. RESULTS: The glycoprotein consists of a heterodimer, M(r) of 120 kilodalton, with subunits of M(r) of 63 kilodalton and 58 kilodalton. Each of the subunits is characterized by an isoelectric point of 6.6 and shows comparable inhibitory activity. Deglycosylation of the subunits show that they share a similar polypeptide backbone (M(r) of 35 kilodalton) based upon a highly similar amino acid profile. This suggests that differential subunit glycosylation alone may account for the apparent heterodimeric structure. CONCLUSIONS: No other human biliary glycoprotein has been found thus far that shows cholesterol crystal growth-inhibiting activity. Thus, it may be of importance in preventing gallstone formation in healthy populations.

Amino Acids↗
PubMed1993

Postural control of fish related to gravity input.

The disappearance of gravity input during space flight causes many functional disorders in animal and human postural control system. On the other hand, it has been shown that these functional deficits reduce or disappear with time and adapt to weightlessness. Unusual fish behavior was reported during the first few days of orbit flight and also during postflight recovery in Skylab 3 experiment. Similar fish behavior was observed in microgravity obtained during the parabolic flight of airplane. These results suggest that fish might provide a good model for investigating adaptation of sensory-motor interaction in microgravity. The fish generally show a "dorsal light response (DLR)" indicating how these postural mechanisms concern with the environment. That is, when a light is presented laterally, a fish rolls its dorsal surface toward the light an equilibrium point between the gravity vector and the light source vector. In addition, the DLR after bilaterally labyrinthectomy or changes of the DLR in microgravity show the involvement of other factors related to the changes of gravity. In this investigation, the behavioral changes of bilaterally labyrinthectomized (BL) and unilaterally labyrinthectomized (UL) fish adapted for more than 3 months on the ground postoperatively were used to analyze whether buoyancy was affected by injecting of a contrast medium into the swimming bladder.

Adaptation, Physiological↗
PubMed1989

[Single-daily-dose treatment of ceftriaxone for biliary tract infections and bacterial counts in bile].

To evaluate the effects of ceftriaxone (CTRX) administered once daily, the biliary concentration of CTRX and daily changes in the bacterial count in bile from an indwelling T-tube were measured concomitantly. The effects on prophylaxis of postoperative infections after biliary tract surgery were also examined mainly due to clinical symptoms. The biliary CTRX levels increased rapidly and were sustained as high as 92.5-219 micrograms/ml in all patients even 24 hours after 2 g of CTRX was infused intravenously once daily. Five of 7 patients whose bile samples were positive for bacteria showed high CTRX levels in bile and almost no bacteria present after treatment. CTRX-sensitive bacteria eliminated 1 or 2 hours after the administration in response to the increase of biliary CTRX levels. The changes in bacteria count of bile may be closely related to CTRX antibiotic activity. As an antibiotic prophylaxis, other 18 patients with biliary diseases received intravenous infusion of 2 g of CTRX once daily for 5-7 days (mean 5.9 days). Thus, once-daily dose treatment of CTRX 2 g may have antibiotic effects on biliary infection and postoperative prophylaxis of biliary infections and it is indicated that the prolonged biliary levels of CTRX are essential for its efficacy.

Adult↗
PubMed1989

Dorsal light response and changes of its responses under varying acceleration conditions.

In order to improve our understanding about functions of the gravity sensors, we have conducted four experiments in goldfish: 1) To define the effect of visual information influx on the static labyrinthine response, the dorsal light response (DLR) which had been proposed by von Holst as a model for postural adjustment in fish was reexamined with a newly designed, rotatory illumination device. The fish responded to illumination from the upper half of the visual field and a narrow range around 180 degrees of the lower half visual field. The maximal tilting angle of normal fish was about 40 degrees under horizontal illumination. 2) Under the changes of the gravito-inertial force level produced by a linear sled, the threshold of the gravity sensors was determined from postural adjustment responses. 3) Under hypogravic conditions during the parabolic flight of an airplane, the light-dependent behavior was investigated in intact and labyrinthectomized goldfish. 4) As one of the most likely candidates of the neural centers for the DLR, the valvula cerebelli, which receives its visual information not through the optic tectum but through the pretectal areas, is confirmed by the brain lesion experiments.

Acceleration↗
PubMed1988

Deacclimation period in ventricular function after high altitude expedition.

Day-by-day changes in ventricular-ejection time/heart-rate ratio (VET/HR) and in ejection time index (ETI), determined by an impedance method in a decompression chamber, were more labile in the mountaineers who had experienced high altitude (above 6,000 m) within the past 1 year, and the ETI values in the first hypoxic exposure were significantly high in these subjects, though close to those of the non-experienced group in the later exposures, suggesting that the effect of hypoxic acclimation on cardiac function might remain at least 1 year after return to sea level.

Acclimatization↗
PubMed1987

Stimulation of anaerobic metabolism in rats at high altitude hypoxia--adrenergic effects dependent on dietary states.

1. Plasma lactate and pyruvate were increased more markedly in fed rats than in fasted rats exposed to an 8000 m altitude. 2. The increase in plasma lactate and pyruvate was enhanced and inhibited by the alpha 1-adrenergic antagonist prazosin and the beta-blocker propranolol, respectively, in fasted rats exposed to an 8000 m altitude. Blood glucose was not changed by adrenergic blockades under the same conditions. 3. Prazosin and propranolol showed no effect on glycolytic metabolites in plasma in fed rats submitted to an 8000 m altitude. Blood glucose of fed rats was increased by alpha 1-blockade during severe hypoxia. 4. In fasted rats whose energy metabolism depends on oxidation mainly, alpha 1- and beta-adrenergic receptors can participate in the stimulation of respiration and the glycogen degradation, respectively, during an exposure to severe hypoxia. In fed rats energy metabolism depends on glycolysis, which utilizes blood glucose as the substrate preferentially during hypoxia.

Adrenergic alpha-Antagonists↗