Biomedical subjects
M Shirataka
Publications and source records attributed to M Shirataka.
Prevalence of soft tissue calcifications in patients with SLE and effects of alfacarcidol.
OBJECTIVE: To clarify the prevalence and etiology of ectopic calcification in patients with systemic lupus erythematosus (SLE), especially under the active vitamin D3 administrations and to reveal the risk factors of ectopic calcification. METHODS: Sixty patients with SLE, excluding the patients on dialysis were studied. We examined radiographs of hands, forearms, upper and lower extremities, and pelvises of all patients to evaluate ectopic calcification. RESULTS: The prevalence of ectopic calcification in SLE was 40% (24 out of 60 patients), found in 6.7% (4 patients) in peripheral arteries, 33.3% (20 patients) in periarticular area and 16.7% (10 patients) in other soft tissues. The incidence of lupus nephritis and nephrotic syndrome were significantly higher (respectively: P=0. 0144 and P=0.0348) in the calcification-positive than negative group. Total protein levels (7.04+/-0.6 g/dl) of patients in the calcification-positive group were decreased significantly (P=0.0056) compared with 7.48+/-0.55 g/dl in the negative group. However, other biochemical parameters were not significantly different between the two groups. Sixty-three percent of the SLE patients with ectopic calcification received alfacarcidol, which is significantly (P=0. 0007) higher than the 19% in patients without calcification. CONCLUSION: It is suggested that the alfacarcidol therapy and lupus nephritis could increase the risk of ectopic calcification in SLE patients.
[Epidemiological research on incidence of atopic disease in infants and children in relation to their nutrition in infancy].
Incidence and relative risk of atopic disease (atopic dermatitis; AD, bronchial asthma; BA, allergic rhinitis; AR) in Japanese infants and children in relation to their nutrition in infancy was analyzed from the data of the epidemiological survey which was conducted for 10,000 mothers of infants and children in 1993. A total of 4,610 replies were received: 2,714 from mothers of infants (12 months old) and 1,896 from mothers of children (2 years old). The subjects were allocated to following 3 groups based on their nutrition during first 3 months after birth; the breast-fed group (BF), the formula-fed group (EF), the mixed-fed group (MF). Incidence of atopic disease in BF, FF and MF was 23.5%, 22.2% and 21.8%, respectively and no statistical difference could be found among these 3 groups. AD was developed 17.0%, 14.4% and 13.9%; BA was 4.4%, 8.5% and 5.2%; AR was 4.9%, 6.5% and 5.8% in BF, FF and MF, respectively. Incidence of AD was significantly different between BF and MF (p < 0.01). Incidence of BA was also significantly different between BF and FF (p < 0.01). Risk of onset of BA and AR in FF was higher (adjusted odds ratio 2.2, 95% confidence interval 1.5-3.2 and adjusted odds ratio 1.5, 95% confidence interval 1.0-2.2, respectively) than that of BF controlled by age and family history with Cochran-Mantel-Haenzel test. With multiple logistic regression analysis, relative risk of the onset of BA in FF at the age of one year was 2.1, 95% confidence interval 1.2-3.5 and at the age of two years old was 2.5, 95% confidence interval 1.4-4.4. These results suggest that the breast-fed have certain suppression effects on incidence of bronchial asthma in infants and children.
Time-lag effect of dietary fiber and fat intake ratio on Japanese colon cancer mortality.
The daily intake of total dietary fiber (TDF) was evaluated from data of the National Nutrition Survey (NNS) in Japan for 41 years since 1947. An interrelationship between the nutrient intake, including TDF, and the mortality from colon cancer in Japanese people was calculated by a simple correlation coefficient and time-series correlation coefficient. TDF intake per capita decreased rapidly from 27.4 g in 1947 to 15.8 g in 1963, and subsequently decreased by a lesser rate to 15.3 g in 1987. Fat intake increased rapidly from 18.0 g in 1950 to 56.6 g in 1987. The age-adjusted mortality from colon cancer shows a significant positive correlation with both the intakes of animal protein and of total fat, and the fat energy ratio. A time-series analysis indicates that the mortality from colon cancer was negatively correlated with TDF with a 15-27 year delay, the maximum correlation existing with a 23-year lag (r = -0.947). The TDF intake was less than 17.9 g in 1965. At the same time, the mortality from colon cancer increased rapidly. A fat/TDF ratio above 3.0 resulted in a rapid increase in colon cancer mortality. The non-adjusted mortality from colon cancer has much the same interrelationship with TDF and fat intake as the adjusted figures. It is suggested that the cause of the increased mortality from colon cancer in Japan is positively related to the increased intake of fat and protein. In addition, the decrease in TDF intake has accelerated the mortality of colon cancer after a delay of 23-24 years. The importance of fat/TDF as a nutritional criterion for the incidence of colon cancer needs to be better recognized.
Mathematical model of cardiovascular mechanics for diagnostic analysis and treatment of heart failure: Part 1. Model description and theoretical analysis.
The planning of drug therapy for heart failure should involve both the diagnostic analysis of the patient's defective state and a prediction of the drug effects on the identified state. We have devised a mathematical model of cardiovascular system mechanics, on which both quantitative diagnosis and evaluation of drug effects can be made. The model was composed of systemic and pulmonary circulatory networks including the dynamics of the left and right ventricles. The model of the ventricles can represent both systolic and diastolic problems in heart failure through the parameters of ventricular contractility and diastolic stiffness. Each vascular network was composed of arterial and venous resistances and total vascular capacitance. Patient's ventricular and vascular parameters were estimated simultaneously from the clinically measurable haemodynamic variables based on the model. Despite the simplicity of the model, the results showed good agreement with clinical and experimental data. The clinically significant haemodynamic classification of heart failure by Forrester et al. (Forrester et al., 1977) was simulated well by the model. This model provides a useful basis for analysing pathophysiological states in heart failure and evaluating drug effects on the disease.
Prenatal ethanol exposure affects the activity and mRNA expression of neuronal membrane enzymes in rat offspring.
In order to elucidate molecular mechanisms underlying brain dysfunction in offspring exposed to ethanol in utero, subclinical doses of ethanol that do not have apparent structural effect on the offspring were administered intraperitoneally to pregnant rats at various gestational stages. We measured the activity of membrane marker enzymes and the level of mRNA of myelin proteins of the offspring brain. The activity of a myelin specific enzyme, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) decreased in ethanol-exposed offspring. This effect was not related to the period of gestation or the dose of ethanol. Perikaryonal enzymes, acetylcholinesterase and Na+, K(+)-ATPase, were significantly affected in groups exposed to ethanol at early fetal stage and in high doses. Expression of mRNAs of CNP and myelin basic proteins decreased significantly in the ethanol-treated group, with abnormal developmental profile suggesting a relationship with delayed myelination in offspring exposed to ethanol in utero. The present findings suggest that in spite of the low doses of ethanol that do not cause clinical symptoms in the offspring, prenatal exposure to ethanol affects the level of mRNA of membrane enzyme proteins in the offspring brain, consequently causing a corresponding reduction in enzyme activity, that may lead to neuronal dysfunction. In a separate study, blood ethanol levels were found to reach a maximum level within 30 min after injection and be undetectable after 5 to 10 h. No accumulation effects due to daily injection were observed.
Isolation of a subclonal cell line of PC12 transfected with dexamethasone-regulated ras oncogene: morphological differentiation, biochemical properties, and tumorigenicity.
We have isolated and characterized a new subclonal cell line designated as MR31, which was obtained by transfection of PC12 cells with a glucocorticoid-regulated ras oncogene. The mRNA derived from the c-Ha-ras gene was proved to be expressed on exposure of the MR31 cells to dexamethasone, the highest value being attained at 8 h. MR31 cells rapidly extended neurite-like processes within 24 h in response to dexamethasone as well as nerve growth factor (NGF). The time of onset of neurite outgrowth induced by dexamethasone corresponded to the time when the highest ras mRNA level was observed. The catecholamine content of MR31 cells was found to be twice that of PC12 cells. A time course study on the effects of dexamethasone or NGF on cells showed that the former caused an increase in dopamine, a major catecholamine, to twofold the control level at 48 h after the treatment, while the latter caused a decrease in the dopamine level. These effects on catecholamines were almost the same in MR31 and PC12 cells. The acetylcholinesterase activity of MR31 cells was enhanced by both dexamethasone and NGF, whereas that of PC12 cells was enhanced by NGF, but not by dexamethasone. The changes in acetylcholinesterase activity were correlated with neurite outgrowth. Electron-microscopically, MR31 cells were not different from PC12 cells. MR31 cells exhibited extremely decreased tumorigenicity as compared with PC12 cells. The morphological and biochemical properties of MR31 cells remained constant, even after repeated passages.(ABSTRACT TRUNCATED AT 250 WORDS)
Evaluation of five computer programs in the diagnosis of second-degree AV block.
Five electrocardiogram (ECG) analyzing systems were tested with a microcomputer-based ECG signal generator to assess the accuracy of the systems in interpreting Wenckebach periodicity. Although normal sinus rhythm with normal PR intervals and sinus rhythms with first-degree atrioventricular (AV) block were diagnosed by all five systems, second-degree AV block with classic Wenckebach periodicity was routinely misdiagnosed by four of the five systems. No system recognized the atypical Wenckebach periods in a total of 200 trials, misinterpreting the phenomenon as atrial fibrillation, supraventricular rhythm, sinoatrial block, and other rhythm disturbances. In advanced AV block and a variety of ventricular arrhythmias, none of the five systems diagnosed second-degree AV block with Wenckebach periods. Marked unsatisfactory performance with regard to the diagnosis of Wenckebach periodicity indicates the urgent need for accelerated and comprehensive testing of ECG diagnostic equipment. The present generating device was seen as an effective troubleshooter in optimizing the diagnostic competency of computerized ECG systems.
[Computer assisted system for diet therapy in chronic kidney failure with maintenance dialysis].
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A mathematical model of atrioventricular conduction block using the excitability recovery curve of the myocardial cell.
A simple mathematical model of AV conduction block was constructed on the basis of single-cell electrophysiological experiments concerning the rate-dependent property of excitability of the AV nodal cells (the excitability recovery curve, ERC). This ERC was analogous to the phase response curve (PRC) of cardiac pacemaker cells, which the authors had previously used to construct a model of modulated parasystole. Computer simulation was used to reproduce the ERC. The single-cell ERC was then extended to the entire AV node, and this curve was used to formulate a mathematical model of AV conduction block as a nonlinear, first-order difference equation of the successive PR intervals of the ECG. This model predicted a variety of ECG patterns of AV conduction block: normal rhythm, first-degree block, and several second-degree blocks of complex Wenckebach periodicity in relation to the sinus rate and the shape of the ERC. By assuming this model it was possible to identify the underlying ERC of actual ECGs with complex Wenckebach periodicity.
Performance of ECG computer programs in the diagnosis of second-degree AV block.
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Usefulness of anaerobic threshold in estimating intensity of exercise for diabetics.
We examined the utility of the anaerobic threshold (AT) for quantifying the intensity of exercise that a diabetic patient is capable of handling. Thirteen diabetic patients treated with buformin exercised on a bicycle ergometer, and comparison was made with 20 healthy subjects matched for age and sex. The AT was determined from VO2 and VE with a personal computer. The intensity of exercise at the AT was 93 +/- 6 W in diabetic men and 80 +/- 10 W in diabetic women, values that were less than those of healthy subjects (P less than 0.05). There was a negative correlation between the intensity of exercise at the AT and the plasma concentration of buformin (P less than 0.01). There were no significant differences in either plasma lactic acid or pyruvic acid concentration at the AT between healthy subjects and diabetics. The plasma glucose at the AT or after exercise was lower than the baseline values in all subjects (P less than 0.01). The plasma insulin at the AT was lower than the baseline values in healthy subjects (P less than 0.01), but not in diabetics. There were no changes in plasma glucagon in any group. We concluded that determination of the AT is a simple, non-invasive procedure useful for ascertaining the optimal intensity of exercise for diabetics.
Response of atrial natriuretic peptide in plasma and urine to changes in dietary intake of sodium chloride in man.
Plasma concentration and urinary excretion of immunoreactive human atrial natriuretic peptide (ir-hANP), aldosterone, and vasopressin were measured, and renal function and blood pressure were determined in six healthy male subjects in three periods of different sodium intake: the control (172 mEq/day), low (20 mEq/day), and high (285 mEq/day) sodium period. Both plasma concentration and urinary excretion of ir-hANP increased significantly in the high sodium period but did not change between the control and low sodium periods. On the contrary, aldosterone increased and vasopressin decreased in the low sodium period but did not change between the control and high sodium periods. These results may point out the reciprocal action of both endocrine systems. The glomerular filtration rate changed in parallel with sodium intake whereas the fractional excretion of sodium decreased only in the low sodium period, probably reflecting the action of aldosterone. It is concluded from these results that the atrial peptide may be an important component in the regulation of body fluid in the high sodium loading of physiological range but its action may be limited to the control of glomerular filtration rate.
[Formulas of acid-base balance].
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Theoretical analysis of "metabolic indices" of blood buffer system.
The well-known base excess (BE) and buffer base (BB) curves of Siggaard-Andersen's nomogram are based on their empirical finding that the blood buffer lines in the pH-log PCO2 coordinates with the same BE (or BB) always pass through a single point irrespective of the hemoglobin concentration. We have analytically derived the BE and BB curves on the assumption of a two-compartmental model of blood buffer system comprised of plasma and red blood cells. These hyperbolic functions of BE and BB curves fitted the Siggaard-Andersen's observation very well. The simple formulas derived from the buffer equation with the parameters obtained on the least-square basis were shown to estimate "metabolic indices" of blood as accurately as the computer reading of the nomographic curves. These results seem to indicate that the buffer equation based on the two-compartmental model describes the acid-base status of blood satisfactorily, and that it can entirely replace the Siggaard-Andersen's nomogram.
[A study on endocrine disorders in patients with chronic renal failure (author's transl)].
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Hemodynamic parameters of the isolated dog kidney as determined by a frequency response method.
The isolated kidney of the dog was perfused with autologous blood through an oxygenator. Responses of arterial input pressure (PI), venous pressure (PV), and venous flow (UV) were measured during sinusoidal forcing of arterial inflow (UA) at 5 to 1,000 cpm superimposed on a steady-state flow level. Pre- (RA) and postglomerular (REV) resistances, and compliances of artery (CA) and glomeruli (CG) were estimated based on a network model and using the Bode diagram of gains PI/UA, UV/UA. The data were evaluated by the least square method with a digital computer. The mean values of the parameters normalized for the average weight of the kidney (64.5g) were: CA = 0.0027 ml/mmHg, CG = 0.088, RA = 0.45 mmHg . min/ml, and REV = 0.35. Mean arterial pressure (PA) and glomerular pressure (PG) were 111 and 50 mmHg, respectively. The regression lines of PG against PA were significantly different at high and low PA, this being taken as a manifestation of autoregulation of the renal circulation. PG values were less than those given by the classical study of Winton but close to those recently obtained on mutants rats with a direct puncture method by Brenner et al. It is concluded that the present study has given an experimental background with which we may continuously estimate, under more intact conditions, circulatory parameter values by monitoring pressures and flows which respond to external perturbations.