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Biomedical subjects

M Toyoshima

Publications and source records attributed to M Toyoshima.

84 records · Page 5Linked to original sources
PubMed1983

Effects of aging on intracellular transport of vitamin B12 (B12) in rat enterocytes.

To elucidate the effect of aging on the vitamin B12 (B12) transport in enterocytes, young and old (3-4 months and over 1.5 years, respectively) female rats were studied. Two units of rat intrinsic factor (IF), saturated with 57Co-labeled cyanocobalamin were orally administered, and the amount of B12 absorbed into each subcellular fraction of enterocytes was assayed. Concentration of endogenous B12 in each subcellular fraction was also studied. Absorption of radioactive B12 in the lysosomal fraction was maximum between 2 and 4 hr in each age group. In the older rats, the amount absorbed was lower than in the young rats. The older rats showed a significantly lower value of endogenous B12 in the mitochondria. It has already been reported by us that there exist two B12 binders in enterocytes: lysosomal and microsomal binders. The concentrations of lysosomal and microsomal binders as well as B12 uptake in the mitochondria were significantly lower in the older rats than in the young rats. These data might help to explain the lower B12 absorption in the lysosomal fraction and lower B12 contents in the mitochondrial fraction.

Aging↗
PubMed1982

Metal contents in duodenal aspirates of normal subjects during pancreozymin-secretin test.

The calcium, magnesium, zinc, copper and manganese concentrations in the duodenal aspirates obtained during pancreozymin-secretin tests were measured in 16 normal subjects. Total outputs of calcium, magnesium, zinc, copper and manganese during the 70 minute period (10 minutes after pancreozymin injection and 60 minutes after secretin injection) were 4.91 +/- 3.47 mg, 1.88 +/- 0.96 mg, 180 +/- 42 micrograms, 162 +/- 104 micrograms and 16.9 +/- 14.2 micrograms (mean +/- S.D.), respectively. The concentrations of metals were the highest in P fraction (during 10 minutes after pancreozymin injection) and the lowest is S3 fraction (during the 20-40 minute period after secretin injection). Although calcium, magnesium, copper and manganese concentrations varied widely from case to case especially in P fraction, zinc concentration exhibited comparatively small variation in every fraction. Magnesium, copper and manganese concentrations exhibited significant correlations with icterus indices of the aspirates. Zinc and magnesium concentrations correlated with amylase activity and magnesium concentration exhibited an inverse relation to bicarbonate concentration. Most metal concentrations correlated well each other, but there were no correlations between zinc and calcium and between zinc and manganese concentrations. Zinc seemed to be excreted mainly with pancreatic juice and copper and manganese mainly with bile.

Adult↗
PubMed1982

Mechanism of uptake of cobalamin into enterocyte mitochondria.

To study the mechanism which cobalamin is taken up by the mitochondria, 57Co-cyanocobalamin-binder complex and freshly prepared mitochondria were prepared from the enterocytes of rats. Subsequently, the binder complex was incubated together with mitochondria in a calcium-containing medium in vitro. Uptake of cobalamin was determined by measuring the radioactivities bound to the mitochondria. Consequently, lysosomal and microsomal binders enhanced cobalamin uptake into the mitochondria, but intrinsic factor did not. It was found that the uptake into the mitochondria was inhibited by previous treatment with calcium-chelating agents. The uptake was completely restored after addition of calcium ions to the mitochondria.

Animals↗
PubMed1982

Brain content of cobalamin and its binders in elderly subjects.

The biological aspects of cobalamin were studied in autopsy brains of eight elderly subjects who had lacked marked neurologic symptoms. Separation of the gray and white matter of the frontal and temporal lobes, and subsequently, subcellular fractionation of each matter were attempted. The contents of cobalamin and its binders and cobalamin concentrations were measured in each subcellular fraction and whole homogenate. The contents of cobalamin were in the ranges of 50 to 60 ng/g wet tissue. No marked differences in contents were found between the frontal and temporal lobes. The mitochondria-rich fraction contained more cobalamin than did the microsomal fraction. Two binders were found; a large-sized and a small-sized. The molecular weight of the larger binder was ca. 120,000, coinciding with the elution region of transcobalamin I, and the molecular weight of the smaller binder was 40,000, coinciding with the elution region of transcobalamin II, in gel filtration respectively. More of the larger binder than the smaller was found in the mitochondria-rich and microsomal fractions. These data are useful for the study of various aspects of cobalamin in brains with various types of neurologic pathology or aging changes.

Aged↗
PubMed1982

Cobalamin contents of the brains in some clinical and pathologic states.

To study the cobalamin content of the brains in various clinico-pathologic states in the elderly, the patho-histology and cobalamin content were examined in autopsy brains with special attention to the temporal and frontal lobes. Consequently, a decrease of cobalamin contents and its binding protein (binder) was found in brains with dementia, severe neuronal loss, myelin degeneration, brain atrophy, ventricular dilatation, and vascular lesions in comparison with those in the controls.

Aged↗
PubMed1980

Determination of manganese in tissues by neutron activation analysis using an antimony pentoxide column.

A rapid and accurate method is presented for the determination of manganese in biological samples, using neutron activation analysis. Biological samples were irradiated at 5000 kW for 30 min. The samples were ashed on a hot plate with 14 mol/l HNO3 and 6 mol/l HClO4, and resolved in 1 mol/l HClO4. 24Na and 24K were removed by passing each sample through in antimony pentoxide column. 54Mn was added as a tracer to calculate the ratio of manganese recovered by the separation procedure. Recovery was over 90%. This method was applied in order to determine manganese in various tissues. In the cervical spinal cord of the controls, the mean manganese concentrations in the anterior horn, the lateral and the posterior columns were 1.14, 1.06 and 0.90 ng/mg of dried tissue, respectively. In two cases if amyotrophic lateral sclerosis the manganese concentrations in the cervical spinal cord were elevated, particularly in the anterior horn and the lateral column.

Amyotrophic Lateral Sclerosis↗
PubMedDate not supplied

Paclitaxel-platinum combination chemotherapy for advanced or recurrent ovarian clear cell adenocarcinoma: a multicenter trial.

The therapeutic effect of a combination of paclitaxel (PTX) and platinum (PLT) in ovarian clear cell adenocarcinoma (CC) patients with measurable disease has yet to be elucidated. In this study, we used retrospective review to evaluate the results of treatment with a combination of PTX and PLT in CC patients with measurable disease. A total of 28 patients with measurable residual CC (15 cases with primary disease, 13 cases with recurrent disease) treated with combination PTX-PLT chemotherapy was identified through medical records from ten institutions. Clinical response to chemotherapy was evaluated using Response Evaluation Criteria in Solid Tumors criteria. Of the 28 cases, 8 of 15 patients with primary disease (53.3%) and 3 of 13 patients with recurrent disease (23.1%) responded to PTX-PLT chemotherapy. The response rate for cases with late recurrent disease (>12 months) was 20% (1/5), whereas the rate was 25% (2/8) for cases with early recurrent (<12 months) or refractory disease. Our results indicate that the combination of PTX and PLT may have greater efficacy against CC than conventional PLT-based chemotherapy that does not include PTX.

Adenocarcinoma, Clear Cell↗
PubMedDate not supplied

Intra-arterial digital subtraction portography with a blood-isotonic, non-ionic, dimeric contrast medium.

Intra-arterial digital subtraction portography (IA-DSP) with a blood-isotonic, non-ionic, dimeric contrast medium was carried out in 27 patients with hepatocellular carcinoma. It was possible to obtain images of excellent or good quality of the portal vein and its bilateral main branches in all patients. The third-order branches of the portal vein in the right lobe could be identified in all patients, and images of excellent or good quality were obtained in a mean of 80.2% of patients. Images of third-order branches in the left lobe were of lower quality than those of third-order branches in the right lobe; in particular, images obtained were of poor quality for 27.3% of the medial branches of the left lobe. It was impossible to identify the caudal branches in almost all patients. The side effects of IA-DSP, pain and sensations of heat were very mild: only one patient complained of mild pain, while 18 patients (69.2%) complained of no sensations of heat whatsoever.

Aged↗