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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 1,117 records · Page 62Linked to original sources
PubMed1982

Methemoglobin in blood as determined by double-wavelength spectrophotometry.

We describe spectrophotometric determination of methemoglobin (Met-Hb) in blood by absorbance differences at two wavelengths (characteristic of the instrument used) in the 500-600 nm region. Blood is diluted 100- to 200-fold with a solution containing KCN and carbon monoxide to convert hemoglobin to carboxyhemoglobin and Met-Hb to cyanomethemoglobin (CN-Met-Hb). Carboxyhemoglobin has the same absorbance at the two wavelengths used, so that the differences in absorbance reflect only the CN-Met-Hb component. After measurement of absorbance differences, potassium ferricyanide is added to convert all hemoglobin derivatives to CN-Met-Hb; samples are then remeasured at the same wavelengths. The percentage of Met-Hb is determined from the ratio of the absorbance differences. Results agree satisfactorily with currently accepted procedures and with calculated theoretical results for mixtures of oxyhemoglobin, carboxyhemoglobin, and Met-Hb.

Carboxyhemoglobin↗
PubMed1982

Structural mutation in a major human aldehyde dehydrogenase gene results in loss of enzyme activity.

Most Caucasians have two major liver aldehyde dehydrogenase isozymes, ALDH1 and ALDH2, while approximately 50% of Orientals have only ALDH1 isozyme, missing the ALDH2 isozyme. A remarkably higher frequency of acute alcohol intoxication among Orientals than among Caucasians could be related to the absence of the ALDH2 isozyme, which has a low apparent Km for acetaldehyde. Examination of liver extracts by two-dimensional crossed immunoelectrophoresis revealed that an atypical Japanese liver, which had no ALDH2 isozyme, contained an enzymatically inactive but immunologically cross-reactive material corresponding to ALDH2, beside the active ALDH1 isozyme. Therefore, the absence of ALDH2 isozyme in atypical Orientals is not due to regulatory mutation, gene deletion, or nonsense mutation, but must be due to a structural mutation in a gene for the ALDH2 locus, resulting in synthesis of enzymatically inactive abnormal protein.

Alcoholic Intoxication↗
PubMed1982

[Assessment of left ventricular function at rest and during exercise by gated cardiac blood pool scan and pressure measurement of the pulmonary artery by Swan-Ganz catheter].

Gated cardiac blood pool scan and hemodynamic parameters by Swan-Ganz catheter were simultaneously measured in five normal subjects (Group A), five patients with coronary artery disease (CAD) without angina on exercise (Group B) and nine patients with CAD with angina on exercise (Group C) in order to evaluate left ventricular function at rest and during supine bicycle ergometer exercise. Work load was gradually increased every 3 minutes and each data were acquired using a digital computer. There was a fairly good correlation (r = 0.83) between stroke volume by thermodilution method and stroke counts corrected by counts/ml of blood on gated cardiac blood pool scan, which were obtained by subtraction of end-systolic counts (ESC) from end-diastolic counts (EDC) in the region of interest arranged at the left ventricle. Stroke counts obtained by this method are considered to reflect a change in the left ventricular volume during exercise. As to the correlation between pulmonary capillary wedge pressure (PCWP) and stroke work index (SWI) at peak exercise, there was a large increase in SWI (78.9 +/- 17.6 to 112.3 +/- 30.0 g X m/m2) with a small rise in PCWP (10.0 +/- 1.9 to 16.2 +/- 4.0 mmHg) in Group A. In Group B, SWI was increased (57.8 +/- 15.8 to 92.9 +/- 25.2 g X m/m2) with a moderate rise in PCWP (11.8 +/- 3.7 to 20.0 +/- 3.1 mmHg) at peak exercise. In Group C, there was a trivial increase in SWI (74.0 +/- 16.0 to 81.2 +/- 29.3 g X m/m2) despite a marked rise in PCWP (13.1 +/- 3.1 to 33.4 +/- 8.9 mmHg). Similar relationship was present between SWI and EDC. On mild exercise of 25w, however, the rise in PCWP was more prominent rather than the increase in EDC in Group C. This indicates that the left ventricle in Group C is operating on a very steep portion of the diastolic pressure-volume curve.

Adult↗
PubMed1981

Argentaffin carcinoid tumor of the rectum.

A case of rectal carcinoid tumor in a 79-year-old Japanese man is reported. The tumor, 1.5 x 0.9 cm, was localized in both mucosa and submucosa of the rectum with neither invasion nor metastasis. Microscopically, neoplastic cells were mainly arranged in rosette-like and trabecular structures within thin fibrous stroma. Histochemically, both argyrophil and argentaffin reactions were positive. At the ultrastructural level, two distinctive types of neurosecretory granules were found in the cytoplasm of tumor cells.

Aged↗
PubMed1981

Purification and characterization of human serum galactosyltransferase (lactose synthetase A protein).

A galactosyltransferase, which transfers galactose from UDP-galactose to N-acetylglucosamine, was purified 286,000-fold to homogeneity with 40% yield from human plasma by repeated affinity chromatography on alpha-lactalbumin-Sepharose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme showed a single protein band with molecular weight of 49,000. The enzyme is a glycoprotein with 11% by weight carbohydrate, which seems to have only asparagine-N-acetylglucosamine linkage-type carbohydrate chains. The enzyme showed characteristic changes in activity at different alpha-lactalbumin concentrations, indicating that the enzyme is the A protein of lactose synthetase. Km values for the substrates were found to be 0.056 mM for UDP-galactose, 3.2 mM for GlcNAc, and 0.44 mM for Mn2+, and in the presence of alpha-lactalbumin, 3.4 mM for Glc, and 0.20 mM for Mn2+. The activity of the enzyme was neutralized by anti-enzyme antibody, but the antibody did not neutralize the bovine milk galactosyltransferase (A protein) activity.

Amino Acids↗
PubMed1981

Non-invasive thymoma with widespread blood-borne metastasis.

A 49 year-old woman with multiple coin lesions in both lungs died three months after admission to hospital for progressive neurologic manifestations due to increasing intracranial pressure. At autopsy, neoplastic lesions were found in the anterior mediastinum, lungs, spleen, cerebrum, liver, right kidney and right ovary. Microscopically, the tumor was composed predominantly of epithelial cells which were arranged in an hemangiopericytoma-like pattern. Rosette formation was also prominent. This case was diagnosed as a thymoma with widespread blood-borne metastasis. Previous reports of metastasizing thymomas are very uncommon.

Brain Neoplasms↗
PubMed1981

Use of cultured lymphoblastoid cells for the study of abnormal enzymes: molecular abnormality of a phosphoglycerate kinase variant associated with hemolytic anemia.

A phosphoglycerate kinase (PGKase: ATP:3-phosphoglycerate 1-phosphotransferase, EC 2.7.2.3; X chromosome-linked) variant, PGKase-Tokyo, is associated with enzyme deficiency, nonspherocytic hemolytic anemia, and neurological disturbances. Because a sufficient amount of the patient's erythrocytes was not available, the variant enzyme was purified to homogeneity from the cultured lymphoblastoid cells of the patient. The enzyme activity of the variant lymphoblastoid cells was about 16% of that of the normal lymphoblastoid cells. PGKase-Tokyo, compared to the normal enzyme, had a lower specific activity (31% of normal in the backward reaction and 15% of normal in the forward reaction), higher than normal Michaelis constants for ATP and 3-phosphoglycerate, a more acidic pH optimum, and increased thermal instability. Microscale peptide mapping analysis revealed that the structural abnormality of PGKase-Tokyo is a single amino acid substitution from valine to methionine at position 266. Thus, the use of the cultured lymphoblastoid cells is proven to be useful for the study of structural and functional abnormalities of mutant enzymes.

Amino Acids↗
PubMed1981

Effect of dietary quality of protein on liver microsomal mixed function oxidase system, plasma cholesterol and urinary ascorbic acid in rats fed PCB.

Exposure of rat to polychlorinated biphenyls (PCB) results in an increase in activity of liver microsomal mixed function oxidase system, plasma cholesterol and urinary ascorbic acid. Experiments were designed to study the effect of dietary quality of protein on these metabolic responses to dietary addition of PCB. The diets contained either whole egg protein, casein, fish protein, soy protein, soy protein plus 0.34% methionine, wheat-gluten, corn-gluten or gelatin fed at 10% of the diet. In general, the relative biological values of proteins as shown by the gains in body weight were positively correlated with activity of the microsomal enzyme system including aminopyrine N-demethylase, aniline hydroxylase, cytochrome P-450 and NADPH-cytochrome c reductase, plasma level of cholesterol and urinary ascorbic acid. Supplement of methionine to soy protein diet containing PCB caused a significant increase in liver and plasma cholesterol and in urinary ascorbic acid, although the influence on the microsomal enzyme system was slight. The gelatin diet containing PCB gave higher activity of the enzyme system than that expected from the biological value, although the same protein diet without PCB caused quite low activity as expected from the biological value.

Animals↗
PubMed1981

Effect of dietary level of ascorbic acid on the growth, hepatic lipid peroxidation, and serum lipids in guinea pigs fed polychlorinated biphenyls.

Rats exposed to polychlorinated biphenyls (PCB) or other xenobiotics exhibit an increase in tissue and urinary ascorbic acid, serum cholesterol and hepatic lipid peroxidation. To clarify the physiological role of ascorbic acid in exposure to PCB, we studied the influence of dietary levels of ascorbic acid (30-2,000 ppm) on the growth, serum lipids and hepatic lipid peroxidation in guinea pigs fed 50 ppm PCB-containing diets. The results showed that the growth depression due to PCB was ameliorated by increasing dietary ascorbic acid. The increases in serum cholesterol and phospholipid and in hepatic lipid peroxidation due to PCB were suppressed by larger amounts of ascorbic acid, which inversely correlated with the changes in growth. PCB intake also increased serum levels of cortisol and triglyceride, but these effects were not influenced by dietary level of ascorbic acid. The optimum requirement of ascorbic acid in the guinea pigs fed PCB was 800-2,000 ppm in the diet for the changes in the growth, serum cholesterol and hepatic lipid peroxidation.

Animals↗
PubMed1981

Effect of some dietary additions to either an arginine-devoid diet or a diet supplemented with orotic acid refed after starvation on liver lipid content during essential fatty acid deficiency in rats.

Refeeding either an arginine-devoid diet or a 14% casein diet supplemented with 1% orotic acid for 7 days to starved rats caused an increase in liver lipid content which was prevented by the addition of adenine, allopurinol and safflower oil, but not guanine, cytosine, thymine and uracil. When rats were refed the arginine-devoid diet unsupplemented or supplemented with guanine, cytosine, thymine and uracil, their serum triglyceride and cholesterol decreased or tended to decrease as compared with those of rats refed the arginine-devoid diet supplemented with either adenine or allopurinol or rats refed the arginine-supplemented diet. Furthermore, triglyceride and cholesterol in serum of rats refed the arginine-devoid diet supplemented with either adenine or allopurinol increased as compared with those of rats refed the arginine-supplemented diet. The addition of either adenine or allopurinol to the arginine-devoid diet resulted in lowered lipid content in the liver as compared with the arginine-supplemented diet. Thus, when the arginine-devoid diet unsupplemented or supplemented with arginine, adenine and allopurinol was refed, liver lipid content was inversely related to the serum triglyceride level.

Adenine↗
PubMed1981

Complete amino acid sequence of mouse liver metallothionein-II.

The complete amino acid sequence of thionein-II, one of the two major mouse liver thionein components, was determined. The main fragmentation of thionein-II, which consists of 61 amino acid residues, was accomplished by digesting the S-[14C]-carboxymethylated protein and the cyanogen bromide-treated oxidized protein with trypsin. The peptides obtained by papain digestion of S-[14C]carboxymethylated thionein-II were used to align the major tryptic peptides. The sequence was determined by a combination of automated and manual Edman degradation techniques. Remarkable structural homology is observed in mouse thionein-I, mouse thionein-II, and thioneins from man and horse.

Amino Acid Sequence↗
PubMed1981

Immunological responses of hamsters in the acquired immune state to Mycoplasma pneumoniae infection.

Protective effects of vaccination of hamsters against Mycoplasma pneumoniae infection, evaluated according to the recovery of mycoplasmas and histopathological changes in the respiratory tract after challenge infection, persisted for at least 6 months after the final vaccination. Serum antibody levels reached a maximum in the second week after the last vaccination and decreased markedly between the first and the third months, but increased again in sera obtained from animals given booster injections. Metabolism-inhibiting antibodies were detected in bronchial washings of animals showing high resistance obtained by vaccinal or passive immunization. Antiserum transfer was also effective for protection but cell-mediated immune responses were not demonstrated in any animals up to 6 months after the vaccination. Even after 10 months, suppression of both mycoplasmal proliferation and lung lesions was apparent, and a single dose of the vaccine induced a significant booster effect. These findings suggest that (1) humoral immunity is more important than cell-mediated immunity in resistance of hamsters to M. pneumoniae pneumonia, and (2) the antibody secreted in the respiratory tract may be involved in the local defense mechanisms.

Animals↗