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Biomedical subjects

A Takabayashi

Publications and source records attributed to A Takabayashi.

70 records · Page 4Linked to original sources
PubMed1986

Changes in plasma phosphate with the stimulation of anaerobic metabolism in rats during hypoxic-anoxic states.

Exposure of rats to high altitude hypoxia causes a rapid decrease in plasma Pi: this change reached the maximum value after exposure to an altitude of 6000-7000 m. Lactate increased markedly when rats were exposed to a high altitude, above 5500-6000 m, although no increase in lactate was observed on exposure to an altitude below 5500 m. Highly anoxic conditions including cyanide and carbon monoxide poisoning cause a marked increase in inorganic phosphate (Pi) and lactate in plasma. Pi entering the intracellular spaces can be utilized as the substrate of oxidative phosphorylation during exposure to an altitude below 5500-6000 m, and for glycolytic enhancement in rats exposed to an altitude above 6000 m. The increase in plasma Pi may be explained by the inhibition of mitochondrial oxidation and the degradation of high energy phosphate compounds under highly anoxic conditions.

Altitude↗
PubMed1985

Cancer of the gallbladder in Bolivia: suggestions concerning etiology.

In order to investigate the very high incidence of gallbladder cancer in Bolivia, a series of patients with gallbladder cancer and/or cholelithiasis from a hospital in La Paz was compared to a series of patients with cholelithiasis from Philadelphia. Each group demonstrated a similar female predilection. Bolivian patients with gallbladder cancer were older than patients with cholelithiasis who, in turn, were older than the general population (p less than 0.001). Racial differences demonstrated previously were confirmed. Bolivian gallstones were uniformly cholesterol in type, in contrast to the US series, in which 27% of patients had black pigment stones. Bile specimens obtained from Bolivian patients with cholelithiasis had a lower concentration of bile salts, phospholipids, and cholesterol than bile specimens from US cholelithiasis patients (p less than 0.01, less than 0.001, and less than 0.001, respectively). These biochemical differences may help to explain the differing incidence of cholelithiasis and gallbladder cancer in the US and Bolivia.

Bile↗
PubMed1983

The epidemiology of cancer of the extra-hepatic biliary tract in Bolivia.

Data on patients with cancer of the gall bladder and cancer of the extra-hepatic bile ducts were obtained from the tumour registry in La Paz, Bolivia. Incidence rates were calculated using the Bolivian census data and compared to US incidence data from the Third National Cancer Survey. The age and population standardized incidence rates for cancer of the gall bladder in Bolivia were 5.3/100,000 males/year and 10.3/100,000 females/year. Comparable US rates were 1.0/100,000 males/year and 2.1/100,000 females/year. The age and population standardized incidence rates for cancer of the extra-hepatic bile ducts in Bolivia were 1.1/100,000 males/year and 4.1/100,000 females/year. Comparable US rates were 1.6/100,000 males/year and 1.0/100,000 females/year respectively. Both diseases occurred at younger ages in Bolivia than in the US and both showed marked racial variation. Differences in disease incidence between Bolivia and the US could not be fully explained by differences in age, sex, or racial distributions. Studies designed to investigate the causes of this remarkable variation in disease incidence could provide important clues to disease aetiology.

Adolescent↗
PubMed1983

Reduction of maximum heart rate in acute, severe hypoxia.

By determining a ceiling for heart rate increase in a given exercise with increment of simulated altitude up to 7,000 m, a reduction of maximum heart rate (HR max) in acute hypoxia was experimentally ascertained. Such a reduction was similarly observed immediately after a high-altitude expedition. In addition, the reduction rate against altitude was close to that shown previously in chronic hypoxia, indicating that the reduction of HR max might be independent of altitude acclimatization.

Acute Disease↗
PubMed1980

Immunological properties of Fc receptor on lymphocytes. VIII. The behaviour of FcR+ and FcR- T cells in cell-mediated immune responses.

The roles of splenic FcR+ and FcR- T cells from mice immunized either with allogeneic cells or with LCMV or stimulated either with MMC-treated allogeneic cells or TNP-modified syngeneic cells in vitro were examined for cell-mediated cytolytic responses. Effective lysis was observed in the FcR- cell fraction enriched with nylon wool eluted T cells in all experiments. Killer cells were generated from the FcR- T-cell fraction after exposure to either allo-, virus- or chemically modified antigen. On the other hand, the lytic activity of the FcR+ T-cell fraction, was low but nevertheless still significant. However, this weak cytotoxicity was increased by 24 h of incubation, although the recovery of living cells was found to be significantly lower in the FcR+ than in the FcR- T-cell fraction. This suggested that non-killer cells, which could interfere with the activity of pre-killer cells, were perhaps preferentially eliminated after binding with the immune complexes. Moreover, almost complete inhibition of lytic activity was achieved in allo-activated FcR+ T, but not FcR- T-cell fraction, after they had been treated with immune complexes, implying a functional significance of FcR in the manifestation of lytic activity.

Animals↗
PubMedDate not supplied

Black and brown pigment gallstones differ in microstructure and microcomposition.

The two subtypes of pigment gallstones, black and brown stones, differ in chemical composition and pathogenesis. We examined a black bilirubinate stone and a black phosphate stone (which represented opposite ends of the compositional spectrum of black noncarbonate stones), a black carbonate stone, and a brown pigment stone using scanning electron microscopy and microchemical techniques to determine if stone microstructure and microcomposition reflected different patterns of formation. The cross-sectional surfaces of the black bilirubinate and black phosphate stones were smooth and homogenous. Electron probe microanalysis demonstrated high concentrations of sulfur and copper in the center of the black bilirubinate stone; sulfur was in a low valence state consistent with disulfide linkages in proteins. The brown stone was rough-surfaced with lamellated bands on cross-section. The lighter-colored bands in this stone contained virtually all of the detected calcium palmitate, while the darker sections contained much more calcium bilirubinate. Plasma oxygen etching demonstrated a network of protein interdigitating with calcium bilirubinate salts in the black bilirubinate and black phosphate stones but not in the black carbonate or brown stones. Argon ion etching demonstrated that calcium bilirubinate was in a closely packed rod-shaped arrangement in all three black stones but not in the brown stone. We conclude that the marked differences in structure and composition between the black noncarbonate and brown pigment gallstones support the hypothesis that the two major pigment gallstone types form by different mechanisms. In addition, the layered structures of the black carbonate and brown stones suggest that stone growth is affected by cyclic changes in biliary composition.

Argon↗
PubMedDate not supplied

CT manifestations of a ruptured hepatic tumor after transcatheter arterial embolization.

There are few reports of the radiologic diagnosis of ruptured hepatic tumors. In a patient with right upper abdominal pain and impending shock, angiography demonstrated a hypervascular hepatic tumor, and CT imaged an extrahepatic mass suggestive of a hematoma. Following transcatheter arterial embolization with Lipiodol Ultrafluide and gelatin-sponge, multiple contiguous CT sections revealed numerous lipiodol droplets adjacent to a lipiodol-containing hepatic tumor, clearly outside the liver. These findings were indicative of a ruptured hepatic tumor. After embolization, the patient's condition improved and he was discharged.

Carcinoma, Hepatocellular↗