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Biomedical subjects

M Inada

Publications and source records attributed to M Inada.

At least 235 records · Page 13Linked to original sources
PubMed1991

Diastolic time in diabetes. Impairment of diastolic time during dynamic exercise in type 2 diabetes with retinopathy.

To evaluate the effect of microangiopathic complications and autonomic dysfunction on diastolic time (DT) during dynamic exercise, 19 patients with type 2 diabetes and ten normal subjects were studied using ear densitography. All subjects had neither an ischemic electrocardiographic response nor chest pain during maximal treadmill exercise. The DT and heart rate (HR) had an inverse nonlinear relation, and electromechanical systole (QS2) and HR had an inverse linear relation during exercise. When the exercise DT-HR and QS2-HR relations were compared, a significant lengthening of QS2, with a consequent shortening of DT, was observed in diabetic patients with retinopathy, compared to patients without retinopathy and normal subjects (p less than 0.005), while no significant differences were found between diabetic patients without retinopathy and normal subjects; however, there were no significant differences in the exercise DT-HR and QS2-HR relations among diabetic patients with and without autonomic dysfunction and normal subjects. A more prominent abbreviation in the diastolic perfusion time observed in patients with retinopathy would be meaningful because microangiopathy might already have limited subendocardial blood flow. Thus, patients with type 2 diabetes who have retinopathy have a potential risk of aggravation of left ventricular function through the deterioration of myocardial blood flow.

Autonomic Nervous System Diseases↗
PubMed1991

Doppler echocardiographic assessment of prosthetic aortic valve function. Findings in normal valves.

To determine the Doppler-derived aortic flow velocity profiles in relation to type of prosthetic valve and left ventricular function, 70 patients with normal functioning aortic prosthetic valves (group 1 = 44 patients with low-profile mechanical valves and group 2 = 26 patients with high-profile mechanical valves) were evaluated. Peak flow velocity and mean systolic gradient were inversely related to valve size (r = -0.72; r = -0.76) in group 1. On the other hand, aortic flow velocity profiles had significant correlations with left ventricular end-systolic dimension (r = 0.75; r = 0.76) and left ventricular fractional shortening (r = -0.69; r = -0.66) in group 2. Thus, aortic flow velocity profiles in the low-profile mechanical valve were affected by pressure gradient caused by the valve size, whereas the hydromechanical disadvantage of the high profile mechanical valve affected the left ventricular pump function and Doppler-derived flow velocity profiles.

Aortic Valve↗
PubMed1991

Effects of atrial natriuretic peptide infusion and its metabolism in patients with chronic renal failure.

Synthetic alpha-human atrial natriuretic peptide (hANP) was infused continuously at a rate of 80 ng/kg/min for 20 min into normal volunteers and patients with chronic renal failure (CRF) receiving hemodialysis. Blood pressure (BP) decreased significantly both in normals and in patients with CRF. The magnitude and the duration of the decrease, however, were greater in patients with CRF. The plasma aldosterone concentration (PAC) decreased significantly in normals and only minimally in patients with CRF. The half time (T1/2) of plasma hANP in patients with CRF (M +/- SE: 4.5 +/- 0.5 min) was longer than that in normals (1.8 +/- 0.2 min). Moreover, the metabolic clearance rate in patients with CRF (64 +/- 7 ml/kg/min) was less than in normals (150 +/- 20 ml/kg/min). Thus, the T1/2 in plasma of hANP in patients with CRF was noticeably longer than in a normal control group. These findings suggest that hANP suppresses PAC regardless of electrocyte imbalances and/or volume change induced by kidney dysfunction and that the kidney may be important in degrading hANP.

Adrenal Glands↗
PubMed1991

Mechanism of thyroid stimulation by human chorionic gonadotropin in sera of normal pregnant women.

To elucidate the mechanism of thyrotropic activity of human chorionic gonadotropin in sera of normal pregnant women, we examined the effect of blockade of the TSH receptor on the serum-induced cAMP accumulation and the effect of hCG on the TSH binding to FRTL-5 cells. In the presence of crude immunoglobulin fractions in sera from patients with primary hypothyroidism, cAMP accumulation induced by both crude and purified hCG, and normal pregnant women serum were significantly inhibited compared with that in the presence of normal IgGs. The mode of inhibition of these IgGs on the cAMP accumulation was similar for TSH and hCG when analysed by Lineweaver-Burk plots. Moreover, binding of [125I]bTSH to the TSH receptor in porcine thyroid cell membrane was apparently inhibited by adding 4 x 10(6) IU/l of purified hCG. Binding studies of TSH in FRTL-5 cells also indicated the dose-dependent displacements of [125I]TSH by hCG. Although half-maximal inhibitory concentration of hCG was about 20 times as high as that of TSH on a molar basis, displacement of [125I]TSH was observed at a concentration of hCG of 10(5)IU/l or more, which could be a physiological concentration of hCG in sera of normal pregnant women. These results suggest that thyrotropic activity of hCG in sera of normal pregnant women is, at least in a part, mediated by TSH receptors.

Animals↗
PubMed1991

Regulation of atrial natriuretic hormone production by triiodothyronine in cultured rat atrial myocytes.

Since thyroid hormones have been reported to increase the synthesis of rat atrial natriuretic hormone and its mRNA accumulation, we further investigated the mechanism of stimulation of rANH synthesis by T3 using cultured rat atrial myocytes. T3 (10(-9)-10(-7) mol/l) increased cellular content and secretion into the medium of immunoreactive rANH in a dose-dependent manner. However, the ratio of secreted/cellular rANH was not altered by the addition of T3. Furthermore, in both cellular and secreted rANH, the larger molecular form (gamma-rANH) apparently predominated over the smaller one (alpha-rANH), and this profile was not influenced by T3 (10(-7) mol/l). Although T3 (10(-9)-10(-7) mol/l) also increased cellular rANH mRNA accumulation, the ratio of cellular rANH/rANH mRNA was not changed. Moreover, using actinomycin D, we found that T3 (10(-7) mol/l) did not affect the degradation of rANH mRNA. From these findings, we suggest that T3 has no specific effects on the translational and posttranslational processes and the release of rANH, but that T3 stimulates rANH synthesis in the pretranslational levels, probably in the transcriptional level of rANH gene.

Animals↗
PubMed1991

[Frequency of complications of mitral valve prolapse in the elderly].

To evaluate the difference in the frequency of complication of mitral valve prolapse (MVP) according to sex in subjects aged 60 years and older, 543 patients (218 men and 325 women) who were diagnosed as having MVP by echocardiography at the Lahey Clinic Medical Center were studied. Three hundred and fourty eight patients had no complication of MVP (male vs female = 129:219). Infective endocarditis occurred in 20 patients (male vs female = 13:7). Rupture of chordae tendineae occurred spontaneously in 29 patients (male vs female = 20:9) and were associated with infective endocarditis in 8 other patients (male vs female = 6:2). Eighteen patients required mitral valve surgery for severe mitral regurgitation. The frequencies of these complications were higher in males than those in females. Cerebral ischemic events were encountered in 54 patients. There was no significant difference in the frequency between male and female. In conclusion, MVP in elderly men might be at for cardiac complication.

Aged↗
PubMed1991

Urinary excretion of glycated protein determined with a specific radioimmunoassay.

We developed a simple and highly sensitive RIA for glycated protein (GP), and used it to measure GP in serum and urine from 15 normal controls and 30 diabetics (14 with urinary excretion rate of albumin, Ualb less than 15 micrograms/min, group A; nine with 15 less than or equal to Ualb less than or equal to 150 micrograms/min, group B; and seven with Ualb greater than 150 micrograms/min, group C). The mean serum concentration of GP was above normal in all groups of diabetics, and the mean glycation ratios of serum protein (SGP) were higher in groups B and C than in normal subjects. Urinary concentrations of GP also were increased in groups B and C, although the glycation ratio of urinary protein (UGP) was decreased in group C. Consequently, the selectivity of urinary excretion of GP (UGP/SGP) was significantly decreased in group C. Moreover, there was a significant difference in the mean values of selectivity between groups of patients with various degrees of retinopathy. We suggest that measurements of serum and urinary GP are useful to evaluate the progression of diabetic complications.

Blood Proteins↗
PubMed1991

[Radionuclide assessment of left ventricular diastolic function in patients with mitral stenosis before and after percutaneous transvenous mitral commissurotomy; use of list mode method in patients with atrial fibrillation].

To evaluate the effect of percutaneous transvenous mitral commissurotomy (PTMC), equilibrium radionuclide angiocardiography was performed in eight patients with mitral stenosis who had atrial fibrillation. Accurate cardiac function in patients with atrial fibrillation is difficult to assess, since the wide fluctuation of cardiac cycle makes the ventricular hemodynamics variable. A new processing algorithm was devised to make multiple gated images discriminated from a heart rate distribution histogram. We obtained about 1,000 beats data by list mode acquisition, and processed a heart rate distribution histogram. The data in the area +/- 5% of the most frequent heart rate were converted into frame mode and a representative time activity curve was derived. Mitral valve area calculated by echocardiography increased from 1.3 +/- 0.5 to 2.0 +/- 0.6 (cm2) significantly (p less than 0.01). The mean transmitral pressure gradient measured by catheterization decreased from 12.4 +/- 5.9 to 4.9 +/- 3.7 (mmHg) significantly (p less than 0.01) and the clinical symptoms improved in all patients. The change in left ventricular ejection fraction from 43 +/- 9 to 48 +/- 13 (%) was not statistically significant, but peak filling rate (PFR) derived from the time activity curve increased from 1.5 +/- 0.3 to 2.0 +/- 0.4 (EDV/sec) significantly (p less than 0.01). Thus PFR is a noninvasive parameter that can evaluate the effect of PTMC.

Adult↗
PubMed1990

Examination of islets in the pancreas biopsy specimens from newly diagnosed type 1 (insulin-dependent) diabetic patients.

We attempted to examine the immunopathological change of the pancreatic islets of newly diagnosed Type 1 (insulin-dependent) diabetic patients and thereby to obtain useful information for the therapy of the patients. For this purpose, pancreas biopsy under laparoscopy was performed 2-4 months after the onset of Type 1 diabetes in seven newly diagnosed patients. All biopsies were performed safely without any complications. Immunohistochemical examination of the biopsy specimens revealed a marked decrease of insulin-containing cells, preservation of glucagon-containing cells, and various degrees of expression of MHC class I and class II antigens in islet cells and in endothelial cells within and around the islets. Signs of active autoimmune phenomena, e.g. lymphocytic infiltration or immunoglobulin deposition in islets, were not detected in any of these patients by light microscopical evaluation. We conclude that pancreas biopsy under laparoscopy has shown various immunological changes in the islets of newly diagnosed Type 1 diabetic patients. Pancreas biopsy, however, may not be suitable under the present protocol for the selection of patients for immunotherapy because of problems including sampling errors.

Adult↗
PubMed1990

Reconstruction of the triangular fibrocartilage complex after surgery for treatment of synovial osteochondromatosis of the distal radioulnar joint.

Synovial osteochondromatosis of the hand is uncommon, except for tenosynovial chondromatosis of the digits. It is even more rare in the wrist joint. A patient with synovial osteochondromatosis of the distal radioulnar joint that involved the triangular fibrocartilage complex is described. At operation, synovectomy, excision of osteochondral bodies, and removal of the entire triangular fibrocartilage complex was done. The triangular fibrocartilage complex was reconstructed using part of the extensor carpi ulnaris tendon. One year after operation, the patient had regained almost full range of motion and is without pain.

Cartilage, Articular↗
PubMed1990

Factors associated with late onset of advanced atrioventricular block in acute Q wave inferior infarction.

To elucidate the clinical characteristics associated with advanced atrioventricular (AV) block that appears relatively late (more than 24 hours) after the onset of myocardial infarction (MI), 101 patients with acute Q wave inferior MI were studied. Fourteen patients had late-onset advanced AV block, and 87 patients were free of AV block. The hospital mortality rate was 11%. Multivariate analysis was performed to determine the important variables associated with the occurrence of late advanced AV block and hospital mortality rates based on 12 clinical variables. Colloid osmotic pressure, right atrial pressure, serum potassium level, and number of segments with advanced asynergy were the significant factors associated with the occurrence of late advanced AV block, whereas advanced asynergic segments and alveolar arterial oxygen difference were important in the consideration of hospital mortality rates. Therefore not only the extent of myocardial ischemia but also the increases in the extracellular potassium level and interstitial fluid are some of the factors that are associated with the occurrence of late advanced AV block in acute inferior MI. Late advanced AV block, in itself, has no significant influence on hospital mortality rates.

Aged↗
PubMed1990

Effect of propranolol on diastolic time during exercise.

To evaluate the effect of propranolol on diastolic time (DT) during uninterrupted upright exercise, 11 men with normal coronary arteries receiving oral propranolol and 10 men with coronary artery disease (CAD) were studied by ear densitography. The DT-heart rate (HR) regression equation during exercise obtained from persons without CAD receiving propranolol was DT = e(6.923-0.014 X HR), which was not statistically different compared to that of normal volunteers with no medication. All 10 men with CAD had ischemic electrocardiographic responses at peak exercise with no medication but had no signs of ischemia during exercise after receiving oral propranolol therapy. Although propranolol caused no significant difference in the DT-HR relation in patients with CAD at 1-min exercise, a significant difference in the DT-HR relation was observed after propranolol therapy at peak exercise. In addition to negative chronotropic action (leftward shift along the DT-HR curve), prevention of disproportionate DT shortening at peak exercise (upward shift of the DT-HR curve) with propranolol through its beneficial action on myocardial ischemia tends to increase myocardial perfusion in patients who, when off propranolol, had ischemic response to exercise.

Adult↗
PubMed1990

Relation between thyroid and cardiac functions and the geriatric rating scale.

To assess the effects of thyroid hormone and cardiac function on senile dementia, relations between serum thyroid hormone concentrations, hemodynamic parameters and dementia rating scale scores were studied in 83 subjects aged 70 and over. Age and serum-free T3 concentrations had a significantly negative correlation in all subjects and in subjects without dementia, but not when analysed only in dementia subjects. Regarding the genesis of dementia, serum free T3 concentrations and cardiac index were both significantly lower in cerebrovascular dementia than in those without dementia. Moreover, subjects with cerebrovascular dementia showed significantly lower serum free T3 concentrations and cardiac index than those with senile dementia of Alzheimer's type in all age groups. These findings suggest that cognitive function is closely related to serum free T3 and cardiac function in subjects with cerebrovascular dementia and that serum free T3 concentrations may be a good indicator, reflecting health and cognitive status.

Aged↗
PubMed1990

Factors associated with pericardial effusion in acute Q wave myocardial infarction.

To elucidate the clinical characteristics associated with pericardial effusion in the early phase of myocardial infarction, 330 patients with acute Q wave infarction were studied. According to echocardiography, 83 patients had pericardial effusion on the third day of hospitalization, and careful auscultation revealed that a pericardial rub was absent in 45 patients and was present in 38 patients. Based on seven clinical variables, multivariate analysis was performed to determine the important variables related to the occurrence of pericardial effusion with and without pericardial rub. Pulmonary capillary wedge pressure and left ventricular segments with advanced asynergy were the significant factors related to the occurrence of pericardial effusion without a pericardial rub. The presence of ventricular aneurysmal motion, left ventricular segments with advanced asynergy, and alveolar arterial oxygen difference were related to pericardial effusion with a pericardial rub. Therefore, a hemodynamic factor was the major mechanism associated with the increase in extravascular myocardial fluid and the consequent occurrence of hydropericardia in the absence of a pericardial rub, whereas an increase in the microvascular permeability in the myocardium with excessive fluid exudating through the irritated epicardial surface was the mechanism related to pericardial effusion with a pericardial rub in the early phase of acute myocardial infarction.

Capillary Permeability↗