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Biomedical subjects

M Kitada

Publications and source records attributed to M Kitada.

At least 181 records · Page 10Linked to original sources
PubMed1987

Bioenergetic properties of alkalophilic Bacillus sp. strain C-59 on an alkaline medium containing K2CO3.

Alkalophilic Bacillus sp. strain C-59 could grow well on an alkaline medium containing K2CO3, as well as Na2CO3, but did not grow on K+-depleted medium. Right-side-out membrane vesicles, energized in the absence of Na+, however, could not take up [14C]methylamine actively, while vesicles equilibrated with 10 mM NaCl actively took up [14C]methylamine. The uptake of [14C]serine was also stimulated by the addition of Na+, and the imposition of a sodium gradient caused transient uptake. These results indicated that an Na+/H+ antiporter was involved in pH homeostasis and generation of an electrochemical sodium gradient in strain C-59 even though a growth requirement for Na+ was not evident. The efflux of 22Na+ from 22Na+-loaded vesicles was more rapid at pH 9.5 than at pH 7 in the presence of an electron donor. On the other hand, vesicles at pH 7 showed more rapid efflux than at pH 9.5 when the antiporter was energized by a valinomycin-mediated K+ diffusion potential (inside negative).

Bacillus↗
PubMed1987

Follow-up study into early adulthood of patients with congenital heart diseases.

Patients with congenital heart diseases (CHD), who had been under our management during school days (elementary, junior high and senior high schools), were followed up into early adulthood (20-38 years in age, averaging at 27.3 years) to obtain the following results. (1) The course of mild CHD until early adulthood was favorable in terms of fatality rate. However, the incidence of complication and resultant deterioration was higher in non-operated mild CHD cases than in operated CHD cases. Representative complications in mild ventricular septal defect (VSD) cases were infectious endocarditis and aortic incompetence (often found in type I VSD cases). A chief complication in mild atrial septal defect (ASD) cases was prolapse of the mitral valve. (2) Patients with VSD or PDA (particularly mild cases) showed spontaneous recovery even in early adulthood. (3) The prognosis of non-operated CHD cases of moderate or higher severity was evidently poor compared to that of mild or operated cases. These results suggest that surgery is indicated in all CHD cases of moderate or higher severity so long as surgery is possible.

Adult↗
PubMed1986

[Clinical investigation on the mechanism of glucose intolerance in Cushing's syndrome].

We investigated the mechanism of glucose intolerance in 51 patients with Cushing's syndrome. In an oral 100g glucose tolerance test, although prevalence of decreased glucose tolerance was very high as revealed in 36 of 47 patients (77%) studied, impairment was rather mild in the majority of patients and only 10 patients (21%) were judged as diabetic. Plasma insulin was measured in 12 patients and the mean values of these patients reached above normal levels after oral glucose load. When insulin secreting capacity was assessed by measuring the ratio of the incremental area of insulin above fasting level to the corresponding area of glucose during the test, Cushing's syndrome as a whole exhibited a normal ratio compared to 9 control subjects (113 +/- 115 vs. 144 +/- 78 microU/mg, M +/- SD, ns), but in 3 patients with severe impairment of glucose tolerance reaching the diabetic range, the ratio was lower than normal (27 +/- 20 vs. 144 +/- 78 microU/mg, M +/- SD, p less than 0.05). The hypoglycemic effect of iv insulin was studied in 23 patients and was demonstrated to have decreased. Thus, we confirmed the presence of decreased insulin sensitivity, i.e. insulin resistance in Cushing's syndrome. The age of patients showed positive correlation with the degree of impairment in glucose tolerance and insulin secreting capacity, but not with that of insulin sensitivity, that is, in patients with advanced age, glucose intolerance appeared to be severe with decreased insulin secreting capacity. 125I-insulin binding to red blood cells in 8 patients was examined to elucidate the mechanism of insulin resistance in Cushing's syndrome. Percent specific binding at tracer concentration of insulin in Cushing's syndrome was not different from the value obtained in 19 normal subjects (8.2 +/- 3.0 vs. 7.7 +/- 1.0%, M +/- SD, ns). Receptor concentration and affinity were also normal. From these observations, it is likely that glucose intolerance in Cushing's syndrome is primarily due to the effects of chronic glucocorticoid excess on tissue metabolism of glucose as characterized by the presence of insulin resistance, which is not due to a defect in insulin-receptor binding but rather caused by the alteration in post-receptor mechanism, and increased secretion of insulin can be considered as a compensatory mechanism. In some patients, however, a decrease in insulin secreting capacity, the cause of which is not clear but at least related to the patient's age, is found and seems to lead to severe glucose intolerance.

Adenoma↗
PubMed1986

Follow up study of acquired valvular heart disease.

In patients with acquired valvular heart disease detected by group cardiac examinations at school, we analyzed follow-up data obtained during school days as well as after graduation from senior high school. Of the 343 patients followed up after graduation from senior high school up to an age range of 20-38 years (mean: 29.3 years), 18 (5.2%) died, 16 (4.7%) deteriorated, 159 (46.4%) remained unchanged, 40 (11.7%) improved, 18 (5.2%) spontaneously recovered and 30 (9.7%) were treated surgically. Of patients who showed spontaneous recovery after graduation from senior high school, 16 cases (8.4%) had mitral regurgitation and 2 (3.6%) had mitral stenosis-regurgitation. In some patients, the disease type changed many years after graduation from senior high school. In particular, the appearance of stenosal lesions in the mitral or aortic valve was often delayed. The mean annual death rate for patients with acquired valvular heart disease (age range: 6-38 years) between April 1962 and March 1983 was 0.65%. The rate peaked at the 15-17 years age range. In recent years, the fatality rate has been falling and no deaths are seen in younger patients. In the past, the leading cause of death in juvenile patients with acquired valvular heart disease was the recurrence of rheumatic fever. For the past ten years, however, no death attributable to the recurrence of rheumatic fever has been registered.

Adolescent↗
PubMed1986

Effects of cytochrome b5 on aniline hydroxylation catalyzed by a reconstituted system containing acetone or 2,2'-bipyridine.

Cytochrome b5 did not exert any effect on NADPH-dependent aniline hydroxylation in the absence of acetone or 2,2'-bipyridine, whereas cytochrome b5 exhibited a stimulatory effect on the reaction in the presence of acetone or 2,2'-bipyridine. In addition, cytochrome b5 did not have any significant effect on the cumene hydroperoxide-dependent reaction in the presence of acetone or 2,2'-bipyridine.

2,2'-Dipyridyl↗
PubMed1986

Enhancement of aniline hydroxylation in human liver microsomes.

Effects of cyanide, acetone, 2,2'-bipyridine and paraoxon on aniline hydroxylation by human liver microsomes were studied. The activity of aniline hydroxylation was inhibited by cyanide when low concentrations of substrate were used, whereas the activity was increased by the addition of cyanide when higher concentrations of substrate were used. Although there were large variences among different liver samples in the extent of the activation of aniline hydroxylation, acetone, 2,2'-bipyridine and paraoxon also exerted stimulatory effects on aniline hydroxylation in human liver microsomes. The degree of the stimulation was not related with the activities observed in the absence of these compounds.

2,2'-Dipyridyl↗
PubMed1986

Effects of fatness on the electrocardiogram in children aged 12-15 years.

Using the 4-Lead Set Japanese Pediatric ECG Screening Criteria Proposal, the effects of fatness on the electrocardiograms were analyzed in 1025 junior high school children, aged 12-15 years (of whom 114 were obese). As the results show, significant differences were detected by the 1% two-sided test between the averages of the nonfat group and the middle- and high-fat groups with regard to S amplitude in leads V1-V3 for boys and girls, R amplitude in leads V4 and V5, SV1 + RV6, SV1 + RV5, and SV3 + RV3 for boys, and S amplitude in leads V4-V6 for girls. High R amplitudes were observed in leads V3 and V4 for the middle- and high-fat group of girls. When applying conventional ECG criteria for left ventricular hypertrophy to the middle- and high-fat groups of boys, the value of SV1 + RV6 greater than or equal to 4.5 mV instead of SV1 + RV6 greater than or equal to 5.0 mV is recommended.

Adipose Tissue↗
PubMed1985

Immunochemical examinations of cytochrome P-450 in various tissues of human fetuses using antibodies to human fetal cytochrome P-450, P-450 HFLa.

P-450 HFLa is a form of cytochrome P-450 purified from human fetal livers. The amounts of P-450 HFLa in several fetal tissues were determined immunochemically. Detectable amounts presented in livers, kidneys, adrenals, lungs and some other tissues of human fetuses. The amounts were the highest in livers. Activities of 7-ethoxycoumarin O-deethylase and benzo(a)pyrene hydroxylase in livers but not in adrenals were inhibited by the anti-P-450 HFLa antibodies, probably suggesting that distinct forms of cytochrome P-450 are responsible for the oxidations in livers and adrenals.

Adrenal Glands↗
PubMed1985

Purification and characterization of S-phenacylglutathione reductase from rat liver.

An enzyme catalyzing the reduction of S-(2,4-dichlorophenacyl)glutathione to 2',4'-dichloroacetophenone was purified to apparent homogeneity by ion exchange, gel filtration, and hydroxylapatite chromatography from rat hepatic cytosol. The molecular weight was 30,000-37,000. The enzyme is distinct from the glutathione S-transferases, mercaptopyruvate sulfurtransferase, and glyoxalase I. Substrate specificity studies showed that S-phenacylglutathiones are the preferred first substrates and that several thiols (glutathione, mercaptoethanol, L-cysteine, or cysteamine) serve as reducing substrates. The enzyme serves to convert toxic alpha-haloketones, which react rapidly and nonenzymatically with glutathione, to nontoxic alkyl ketones.

Amino Acids↗
PubMed1985

Purification and properties of cytochrome P-450 from homogenates of human fetal livers.

A form of cytochrome P-450, namely P-450HFLa of human fetal livers, was purified to a specific content of 12.6 nmol/mg protein. The cytochrome P-450 preparation was electrophoretically homogeneous and had an apparent monomeric molecular weight of 51,000 as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The cytochrome showed catalytic activities as oxidations of N-methylaniline, ethylmorphine, N,N-dimethylaniline, N,N-dimethylnitrosamine, benzphetamine, aminopyrine, aniline, p-nitroanisole, and 7-ethoxycoumarin to various extents. In fetal liver homogenate, the amount of cytochrome P-450 that reacted with the antiserum to P-450HFLa accounted for more than 36% of the total cytochrome P-450 in three different fetal livers. On the other hand, the amount of P-450HFLa was less than 5% of the total cytochrome P-450 in adult liver microsomes.

Adult↗
PubMed1985

Different effects of cyanide on the activities of 7-ethoxycoumarin O-deethylation catalyzed by two forms of cytochrome P-450 purified from 3-methylcholanthrene-treated rats.

The effect of cyanide on 7-ethoxycoumarin O-deethylation by two cytochrome P-450 isozymes obtained from 3-methylcholanthrene treated rat liver microsomes was investigated. 7-Ethoxycoumarin O-deethylation was stimulated by the addition of cyanide to a reconstituted monooxygenase system consisting of NADPH, dilauroyl 3-L-phosphatidylcholine, NADPH-cytochrome P-450 reductase and MC P-448(2) (low spin form of cytochrome). In contrast, a weak inhibitory effect of cyanide on 7-ethoxycoumarin O-deethylation was observed when MC P-448(1) (high spin form of cytochrome) was used in the reconstituted system. Cyanide did not influence the apparent Km for 7-ethoxycoumarin when either form of cytochrome P-450 was used in the reconstituted system and did not stimulate the cumene hydroperoxide dependent O-deethylation by MC P-448(2). The stimulatory effect of cyanide on O-deethylation by MC P-448(2) was decreased with increasing the concentration of the reductase added to the reconstituted system. On the other hand, the effect of cyanide on O-deethylation by MC P-448(1) was virtually independent on the amount of the reductase added.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1985

[Image diagnosis of adrenal disorders--II. Cushing's syndrome].

Comparative study of image diagnosis of ultrasonography (US) by linear electronic scanner, computed tomography (CT), and adrenal scintigraphy was performed in 14 patients with Cushing's syndrome. Adrenal imaging by scintigraphy was performed at the 5th and 6th day or further 7th day following the injection of 1 mCi of Adosterol. Cushing's disease (11 cases) US failed to detect the adrenals in 4 cases examined. Measurement of the adrenals on CT film demonstrated the enlargement of adrenals (greater than mean + 2SD) in 6 of 7 cases (85.7%). Scintiscanning showed the increased uptake of bilateral adrenals in 4 of 10 cases (40%). Adrenal scintigraphy with dexamethasone pretreatment (DP) still demonstrated the isotope uptake of bilateral adrenals in all of those 4 cases tested, although the other 6 cases were not studied with DP. From these findings, it was suggested that the measurement of adrenal size by CT was useful for the additional image diagnosis of Cushing's disease, and the adrenal scintigraphy with DP was also available for complementary study of Cushing's disease. Cushing's syndrome due to adrenocortical adenoma (3 cases) In one case examined by US, which had the smallest adenoma (0.6 X 1.0 X 2.0 cm) in this syndrome, the adenoma was not detected. All of 3 adrenal adenomas (2.6 X 2.6 X 2.2 cm to 0.6 X 1.0 X 2.0 cm) were detected by CT. Adrenal scintigraphy demonstrated good uptake by adrenal adenoma but no visualization of the contralateral adrenal in every case.

Adenoma↗
PubMed1985

A study on exercise test for mass examination of heart disease.

One thousand and twenty-two of senior high school students and 274 of primary and junior high school students screened as positive through heart disease mass examination were tested by the Master's two step Method. The results are as follow: 1) In order to get informations to give the guide line for school life, it is still insufficient triple amounts of exercise performed during 3 minutes and 45 seconds for high school male students although this may be appropriate for primary, junior high school students and female senior high school students. 2) Fatigue and their history concerning to athletic activity should not be neglected to evaluate the results of exercise test. 3) It is important to consider before evaluation of the test that QTc immediately after exercise shorten by 6 to 8% and QTc 3 minutes after the exercise prolonged by 3 to 4%.

Adolescent↗
PubMed1984

Purification and characterization of a pancreas cancer-associated antigen from normal colonic mucosa.

Pancreas cancer-associated antigen (PCAAc) was extracted, isolated and purified from human normal colonic mucosa. Purified PCAAc from normal colonic mucosa was homogeneous, as determined by polyacrylamide disc gel electrophoresis. The PCAAc had a molecular weight of approximately 600 000 and consisted of 30% carbohydrate and 70% protein. It had an isoelectric point of 4.4, and migrated to the alpha 2-beta region on immunoelectrophoresis. It was apparently different from other known gastrointestinal mucus antigens. Antiserum against purified PCAAc did not react with normal human serum, pancreas, liver, spleen or lung, but did react with ascites fluid from a patient with pancreatic cancer. PCAAc appears to be a mucus antigen that is associated with pancreatic cancer.

Amino Acids↗