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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 1,063 records · Page 59Linked to original sources
PubMed1983

Superficial carcinoma of the esophagus.

Nine cases of superficial carcinoma of the esophagus were described. Although 3 patients complained of abdominal sensations on swallowing or dysphasia, 6 patients did not present with any symptoms related to the esophageal lesion. The radiologic diagnosis is particularly difficult in cases with superficial type esophageal cancer, and no definitive findings were obtained in three such cases. However, esophagoscopy using Lugol spray was far more effective for the recognition of these superficial lesions. Although surgical resection of the esophagus is technically easier in these cases, the indications of surgery should be carefully evaluated. One operative death occurred in our series. In cases that are good indications, however, wide lymph node dissection should be carried out, since metastases occur even to distant lymph nodes, particularly in cases with cancer invasion of the submucosal layer. The histopathologic diagnosis was squamous cell carcinoma in 8 cases, but in one case it was adenocarcinoma of mucus-secreting gland origin in the mid-thoracic esophagus.

Aged↗
PubMed1983

Retinal circulatory changes after scleral buckling procedures.

The noninvasive laser Doppler technique was used to study retinal circulatory characteristics in five patients who underwent uncomplicated scleral buckling procedures. In each patient, the systolic/diastolic variation of the red blood cell speed in the retinal arteries (flow pulsatility ratio) was lower in the eye that had received an intrascleral implant and an encircling band than in the fellow eye. In one patient, an increase in flow pulsatility ratio accompanied an increase in retinal blood flow after removal of the scleral buckling elements. In another patient, the flow pulsatility ratio in the eye that had received a solid implant and an encircling band was less than the ratio in the fellow eye that had received an absorbable implant alone. Our results indicated that reduced retinal blood flow may be common after scleral buckling procedures, and may be a significant factor in otherwise inexplicable postoperative complications.

Adult↗
PubMed1983

Preparation of neuraminidase-resistant human alpha 1-protease inhibitor and its clearance in rat blood circulation.

The sialic acid residues of human alpha 1-protease inhibitor were modified by periodate oxidation and subsequent reductive amination with ethanolamine and sodium cyanoborohydride. The modified inhibitor retained its original trypsin inhibitory activity and was not digested by neuraminidase from Clostridium perfringens. The modified inhibitor disappeared from rat blood circulation at the same rate as the native inhibitor.

Animals↗
PubMed1983

Effects on liver and serum lipids of dietary supplements of methionine and excess lysine given to previously-starved rats.

The addition of lysine hydrochloride (50 g/kg) to a diet supplemented with methionine (3 g/kg) had no effect on liver lipids when rats (Wistar and Sprague-Dawley) were fed ad lib. for 14 d. However, refeeding a diet supplemented with methionine and excess lysine hydrochloride to previously-starved rats (Wistar) for 6, 7 or 9 d, but not 3 or 4 d, resulted in liver lipid accumulation, mainly triglycerides, which was prevented by the addition of arginine, citrulline, ornithine, adenine, allopurinol or maize oil, but not by guanine, cytosine, thymine or uracil. The addition of lysine hydrochloride to a methionine-supplemented diet resulted in reduced serum triglyceride levels after refeeding for 3 or 4 d and reduced serum cholesterol levels after refeeding for 3, 4 or 6 d. Serum lipids were unaffected by refeeding the diets for 7 or 9 d. Since hepatic lipid accumulation was preceded by the decline in the level of serum triglycerides, one of the factors responsible for lipid accumulation in the liver might be reduced transport of triglycerides from the liver into the blood. When adenine and allopurinol were added to the diet supplemented with methionine and lysine hydrochloride refed for 4 d, there was an increase in serum triglycerides. However, when this diet was refed for 7 d, with the addition of arginine, citrulline, guanine, pyrimidine bases, allopurinol or maize oil, no effects on serum cholesterol and triglyceride levels were observed.

Animals↗
PubMed1983

Effect of dietary fiber on hypercholesterolemia induced by dietary PCB or cholesterol in rats.

Effects of 0.03% polychlorinated biphenyls (PCB) in the diet and various dietary fibers [konjac mannan (KM), pectin, sodium carboxymethyl cellulose (CMC) and cellulose] at a 5% level in the diet on serum and liver lipid metabolism and urinary ascorbic acid were studied. A comparison between dietary PCB and 1% cholesterol in the diet was also made. Serum albumin, protein, total and high density lipoprotein (HDL)-cholesterol, triglyceride, urinary and liver ascorbic acid, liver cholesterol and total lipids were increased in rats fed PCB. Pectin or KM depressed the elevation in serum protein, total and HDL-cholesterol, triglyceride and liver lipids due to PCB intake. Cellulose or CMC had no significant effect on these indices. Urinary ascorbic acid was not decreased by these dietary changes. Serum total cholesterol and low density lipoprotein (LDL) plus very low density lipoprotein (VLDL)-cholesterol, and liver total lipids, and cholesterol were significantly higher, and serum HDL-cholesterol and triglyceride were significantly lower in the cholesterol-fed group as compared to PCB-fed rats. Addition of KM to a cholesterol diet significantly depressed serum total cholesterol and LDL plus VLDL-cholesterol, liver cholesterol and total lipids. It seems likely that cholesterol metabolism is quite different during dietary PCB and cholesterol feeding.

Animals↗
PubMed1983

Overall "gain" of the respiratory control system in normoxic humans awake and asleep.

With the addition of external dead space in normoxia, PCO2-ventilation response and CO2 production were determined in 10 healthy male subjects. Overall "gain" (G) of the respiratory control system was calculated from the slope of the CO2-response curve (S) and that of the metabolic hyperbola (SL) at alveolar partial pressure of CO2 (PACO2) of the respective experimental run. We found that 1) despite the depression of ventilation during non-rapid-eye-movement (NREM) sleep, G was generally not changed due to decreased SL, although considerable individual variations were seen; 2) effects of external dead space on PACO2 change during sleep and wakefulness were similar in magnitude; and 3) the above PACO2 changes experimentally induced agreed well with the predicted values estimated from G. Contrary to general opinion, these results demonstrated that overall gain of the respiratory control system is generally not depressed during NREM sleep in normal healthy subjects.

Adult↗
PubMed1983

Biopotency and nuclear binding of glucocorticoids.

Nuclear binding abilities of 3 glucocorticoids, dexamethasone (Dex), prednisolone (Pred) and corticosterone (Cort), which exhibited different biopotencies were compared in vitro. cytosols labelled with 3H-Dex, 3H-Pred and 3H-Cort from the rat liver prepared by incubation at 0 degrees C for 16 hr were bound to isolated liver nuclei in rates of approximately 25%, 9% and 1% of added radioactivity, respectively. Nuclear binding rates observed were correlated with biopotencies of these steroids. Time course studies of the cytosol binding revealed that the difference in the nuclear binding ability of these ligands was attributable, at least in part, to the metabolic transformation of ligands during the incubation period. A significant portion of 3H-Pred and 3H-Cort was transformed to polar metabolite(s) even under the incubation conditions at 0 degrees C. Kd's of the cytosol binding to 3H-Dex which was metabolically stable were decreased with the length of incubation time, significantly lower Kd being observed in the cytosol incubated for 16 hr than in those incubated for 2 and 6 hr. Kd's and the number of maximum binding sites were erratic when the ligands received biotransformation during the course of incubation. Transformed 3H-Pred and 3H-Cort during the incubation still exhibited features of the protein bound state. Besides biotransformation of ligands, structure related difference in the nuclear binding ability of these glucocorticoids was also observed. These observations suggest that metabolic susceptibility as well as structure related ability of the nuclear binding may contribute to the biopotency of glucocorticoids.

Animals↗
PubMed1983

Mechanisms of adverse effect of amaranth feeding in the rat.

In order to clarify the mechanism of the adverse effects of dietary amaranth, trisodium 1-(4-sulfo-1-naphthylazo)-2-naphthyl-3,6 disulfonic acid, the effects of amaranth in vitro and in a jejunum perfusion in vivo on intestinal sucrase were investigated in rats. The inhibitory effect of amaranth in vitro on the sucrase activity was not detected even at the concentration of 1%, whereas the remarkable release of intestinal sucrase from intestine was observed with the jejunum perfusion of Ringer bicarbonate solution (RBS) containing amaranth at the 1% level. On the other hand, the perfusion of RBS containing tris(hydroxymethyl)-aminomethane, a strong inhibitor of intestinal disaccharidase activities, did not produce the release of intestinal alkaline phosphatase. These findings suggest that the toxicity of dietary amaranth is due to the exfoliating or solubilizing effects of amaranth on the brush border membrane of the small intestine.

Alkaline Phosphatase↗
PubMed1983

Effect of several xenobiotics on the activities of enzymes affecting ascorbic acid synthesis in rats.

The dietary addition of several xenobiotics, such as PCB, DDT, aminopyrine, chloretone, BHT and BHA, caused significant increases in the ascorbic acid in urine and liver of rats. The administration of all types of xenobiotics used in the present experiments increased the activity of hepatic UDP-glucose dehydrogenase (1.3-2.8-fold), and the administration of PCB, DDT, BHT or BHA significantly increased the activity of hepatic UDP-glucuronyl transferase (2.2-13.1-fold). The activity of beta-glucuronidase was slightly increased with feeding of PCB, DDT, chloretone or aminopyrine. However, the activity of hepatic UDP-glucuronic acid pyrophosphatase, the conversion of D-glucuronic acid or D-glucuronolactone into L-ascorbic acid and the activity of hepatic L-gulonolactone oxidase did not increase with the administration of PCB or DDT. It is suggested that the increases in the activities of UDP-glucose dehydrogenase and UDP-glucuronyl transferase would have a major role in the stimulation of ascorbic acid synthesis in xenobiotic treated rats.

Aminopyrine↗
PubMed1983

Peplomycin sulfate and pulmonary fibrosis: hydroxyproline, uronic acid, proline hydroxylase and glucosamine 6-phosphate synthetase in lungs of hamsters treated with peplomycin.

Effect of peplomycin sulfate (PLM) on pulmonary fibrosis was examined. Hydroxyproline, uronic acid, proline hydroxylase (EC 1.14.11.2) and glucosamine 6-phosphate synthetase (EC 2.6.1.16) in lungs of hamsters treated with PLM were studied and compared with those of hamsters treated with bleomycin (BLM). PLM, when administered intraperitoneally, one injection daily for 10 consecutive days, at either a high- (5 mg/kg) or low- (2.8 mg/kg) dosage-level, caused no significant increase of lung hydroxyproline and uronic acid as compared with controls. BLM on the other hand effected a significant increase in lung hydroxyproline on the high-dosage level (5 mg/kg) but not on the low-dosage level (2.8 mg/kg). In contrast, when administering PLM intratracheally, the concentrations of hydroxyproline in lungs increased 20% over the control levels. A transient increase of proline hydroxylase and glucosamine 6-phosphate synthetase also occurred shortly after the instillation. These increases were also observed in the corresponding groups treated with BLM, which confirmed the previous observations by other investigators. However, the magnitude of the increase was relatively lower in those values of PLM as compared with those of BLM. These data suggested that (1) PLM, when administered with multiple dosages intraperitoneally, showed no significant effect on the elevation of lung hydroxyproline; (2) PLM, when administered with a dose intratracheally, induced pulmonary fibrosis similar to that caused by BLM. However, the hydroxyproline accumulation in lungs of PLM-treated hamsters was less than in those of the BLM-treated; (3) The fibrotic effect on the lungs caused by either PLM or BLM was probably attributed to acceleration of the syntheses of collagen and acidic glycosaminoglycans.

Animals↗
PubMed1983

Differences in the isozymes involved in alcohol metabolism between caucasians and orientals.

Acute alcohol intoxication is far more commonly observed in Orientals than Caucasians. The human liver contains several cytosolic and microsomal ADHs. One of the major cytosolic ADH isozymes controlled by a gene at the ADH2 locus differs between Caucasians and Orientals. Most Caucasians have the usual enzyme consisting of usual beta 1 subunit, while nearly 90% of Orientals have the atypical enzyme consisting of the atypical beta 2 subunit. The specific activity of the atypical enzyme is several times higher at pH 10 and nearly 100 times higher at physiologic pH than the usual enzyme. Km values for ethanol, NAD, acetaldehyde, and NADH are several times higher for the atypical enzyme than for the usual enzyme. The usual enzyme is rapidly inactivated by iodoacetate, indicating the existence of an "active-site cysteine" in the molecule. In contrast, the atypical enzyme is resistant to iodoacetate inactivation. Peptide mapping analysis revealed that the active site Cys in the usual beta 1 subunit is replaced by His in the atypical beta 2 subunit. A remarkable structural homology exists at the active site of horse and human enzymes. In the usual beta 1 beta 1 enzyme, as in the horse enzyme, the catalytic Zn is expected to link to the sensitive Cys at position 47, His at position 67, and Cys (presumably) at position 174, thus forming the active site. In contrast, the active site of the atypical beta 2 beta 2 enzyme is expected to consist of the catalytic Zn linked to His at position 47, His at position 67, and Cys (presumably) at position 174. The resistance of the atypical beta 2 beta 2 to inactivation by iodoacetate is a direct consequence of the replacement of the sensitive Cys at position 47 by His. Liver ALDH components also differ between Caucasians and Orientals. Virtually all Caucasians have two major ALDH isozymes, ALDH1 and ALDH2, while approximately 50% of Orientals have only the ALDH1 isozyme (cytosolic) missing ALDH2 isozyme (presumably mitochondrial). ALDH1 consists of four subunits with a molecular weight of 56,500, and ALDH2 consists of four subunits with a molecular weight of 52,600. The two isozymes do not share any common subunit. Examination of liver extracts by two-dimensional crossed immunoelectrophoresis revealed that an atypical Oriental liver with no ALDH2 isozyme contained an enzymatically inactive but immunologically cross-reactive material corresponding to ALDH2, besides the active ALDH1 isozyme.(ABSTRACT TRUNCATED AT 400 WORDS)

Alcohol Dehydrogenase↗
PubMed1983

Effect of pharmacological doses of estrogen on ovary-independent rat mammary carcinoma containing estrogen and progesterone receptors.

Mammary carcinoma induced in male Sprague-Dawley rats by multiple intragastric intubations of 7,12-dimethylbenz-(a)anthracene showed ovary-independent growth but contained estrogen receptors (ER) and progesterone receptors (Yoshida, Yoshida. Fukunishi, Sato, Okamoto, and Matsumoto, Cancer Res., 42: 2434-2439, 1982). Transplantable carcinoma (MT6) was obtained from dimethylbenz(a)anthracene-induced mammary carcinoma and then maintained in male rats. MT6 tumors with ER grew equally well in males, females, gonadectomized males, males given injections of bromocryptine (1 mg/day) or lisuride hydrogen maleate (50 micrograms/day), and gonadectomized males receiving smaller doses of 17 beta-estradiol (1 to 100 micrograms/2 days). However, the growth of MT6 was inhibited markedly by injection of a very large amount of 17 beta-estradiol (1 mg/2 days). Although transplanted MT6 tumors were ductal carcinoma with cribriform pattern with ER, tumors recurring after injection with 1 mg 17 beta-estradiol were found to be spindle cell carcinoma without ER, which could grow equally well in recipients treated with or without 1 mg 17 beta-estradiol. These observations suggest that the growth of ovary-independent MT6 tumors with ER and progesterone receptors is inhibited only by pharmacological doses of estrogens and that the loss of growth-inhibiting effect of pharmacological doses of estrogen of MT6 tumors occurs during high-dose estrogen treatment.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

The existence of atypical blood group galactosyltransferase which causes an expression of A2 character in A1B red blood cells.

It is generally accepted that the blood group subtypes A1 and A2 expressions are controlled by two different blood group N-acetylgalactosaminyl-transferases, that is, A1-enzyme and A2-enzyme, respectively, and that the two types of enzymes are governed by the allelic A1 and A2 genes. The observed frequencies of blood types in Caucasians are compatible to this model. However, the subtype A2 character is far more frequently observed in AB red cells than in A red cells in some black and Oriental populations. Two black blood samples with phenotype A2B contained A1-enzyme, but not A2-enzyme, and exhibited several times higher B-enzyme activity than control AB and B blood. The kinetic properties, that is, pH-activity profile and Km for UDP-Gal, of the B-enzyme from these two A2B subjects differed from that of control B-enzyme. In these two cases, therefore, the A2 character was not caused by the subactive A2-enzyme, but because of an insufficient formation of the A-substances in red cell membranes presumably caused by the competition between the A1-enzyme and the super active atypical B-enzyme at the common H-sites. The results suggest that the B gene can be subdivided into usual B1 and atypical B2, and that not only A2B subjects but also A1B2 subjects could express A2 character in their red cells. The B2 gene may be common in certain black and Oriental populations.

ABO Blood-Group System↗