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Biomedical subjects

M Yoshimura

Publications and source records attributed to M Yoshimura.

At least 613 records · Page 34Linked to original sources
PubMed1989

[Influence of pregnancy on IgA nephropathy].

In an attempt to clarify the influence of pregnancy on the natural course of IgA nephropathy, the courses of 79 pregnancies occurring in 47 patients with the disease were studied. These resulted in 3 artificial and 10 spontaneous abortions, and two pre-term and 64 full-term deliveries. Fifty four maternity passbooks were analyzed. In 22 pregnancies (40.7%) proteinuria was increased during the third trimester, and in 13 (76.5%) of 17 pregnancies receiving postpartum urinalysis, urinary protein was decreased to the level of the first trimester within one month after delivery. In two of the remaining four patients with a persistent increase in proteinuria, renal biopsy was carried out two months after delivery, revealing focal glomerular sclerotic lesions, in addition to mild mesangial proliferation compatible with IgA nephropathy. These findings indicated that increased urinary protein observed in the two pregnancies might be attributed to a complication of pre-eclamptic focal glomerular sclerosis rather than exacerbation of underlying IgA nephropathy. The glomerular filtration rate (GFR), examined in 27 patients both before and after pregnancy, was decreased in only two patients (7.4%), but these reductions appeared to go with the individual natural course. In 6 (15.0%) of 40 pregnancies, proteinuria was increased within one month after delivery, and one of them was diagnosed both clinically and pathologically as the acute exacerbation of IgA nephropathy. These data suggest that patients with IgA nephropathy might show transient acute exacerbation just after delivery rather than during pregnancy, and that even if such exacerbations occurred, pregnancy might have little influence on the natural course of the disease.

Adult↗
PubMed1989

[A case of cardiac sarcoidosis with various electrocardiographic change].

The patient was a 61 year old woman of Japanese who was in good health until May 1983, when she came to our hospital because of the visual disturbance. The chest X-ray film showed bilateral hilar lymphadenopathy and a transbronchial lung biopsy revealed sarcoid granuloma. She received systemic steroids (10 to 40 mg/2 days of prednisolone) for visual disturbance from August 1983 to May 1986. Then steroid therapy was suspended temporarily. In August 1987, she was readmitted because of syncopal episodes. She was noted to have irregular bradycardia and the electrocardiogram revealed atrioventricular block and paroxysmal polymorphous ventricular tachycardia. Initially cardioversion to sinus rhythm was accomplished with direct current electric shock and temporary pacemaker was inserted and subsequently a permanent transvenous demand pacemaker implanted. The patient then became asymptomatic. Coronary arteriography revealed no significant organic stenosis and left ventriculogram showed a left ventricular aneurysm of the inferior wall of the left ventricle. A transvenous percutaneous right ventricular endomyocardial biopsy revealed non-specific myocardial degeneration with slight interstitial fibrosis. Thallium-201 myocardial perfusion scans revealed the inferior left ventricular defects. We conclude the syncopal episodes and electrocardiographic abnormalities of this case were due to massive myocardial sarcoidosis which caused left ventricular aneurysm.

Cardiomyopathies↗
PubMed1989

[Progressive supranuclear palsy accompanied with progressive subcortical vascular encephalopathy of Binswanger type--a case report].

We report the clinical and neuropathological findings in an autopsy case of progressive dementia, Parkinsonism, pseudobulbar palsy and supranuclear ophthalmoplegia. Since 70 years old, this hypertensive patient developed forgetfulness, unsteady gait and festination. These symptoms rapidly worsened and he was admitted in October 1983, at age 71. He had severe dementia and showed stiff face. Voluntary vertical movement of the eyes was severely disturbed, but reflex vertical movement by the doll's head eye maneuver was not affected. Muscle tone in the limbs increased slightly, and deep tendon reflexes were hyperactive in jaw and the upper extremities. Babinski sign was negative bilaterally. Sensation and coordination remained normal. Although he was not paretic or ataxic, his movements were very slow. He could not stand by himself and easily fell backward. These clinical features resembled those of progressive supranuclear palsy except for severe dementia and rapid progression. Brain CT scan revealed marked dilatation of the lateral ventricles, prominent periventicular lucency and atrophy of brainstem and cerebral cortex. Treatment with levodopa slightly improved his movement, but difficulty in swallowing worsened increasingly. He died of hypoglycemic coma and aspiration pneumonia in September 1984, about two years after the initial symptoms. General autopsy showed severe pneumonia and atrophy of the liver. The brain weighed 1,210g. Atherosclerotic change in the cerebral arteries were mild. Coronal sections of the cerebral hemispheres revealed diffuse ischemic change and multiple small infarctions in the bilateral cerebral white matter. Cortical atrophy was observed in the cerebral hemispheres. The basal ganglia, thalamus, and pons showed status lacunaris. Atrophy of midbrain and depigmentation of the substantia nigra were observed macroscopically.

Aged↗
PubMed1989

[Median sternotomy for lung and tracheal surgery].

Median sternotomy was used in 30 cases of lung surgery; (1) lung cancer with impaired pulmonary function or local invasion to the mediastinum-12 cases. An average FEV1.0, 960ml, 38% FVC was only reduced to 890ml one month after lobectomy. (2) concomitant heart disease-2 cases. A 5 year old boy, with tracheal stricture and tetralogy of Fallot, was successfully treated by one stage operation. Stenotic cartilage trachea, 2mm in diameter, was resected 15mm in length and anastomosed end to end under total extracorporeal circulation after cardiac operation. A left upper lobectomy for lung cancer was performed under partial extracorporeal circulation after mitral valve replacement and valvoplasty of tricuspid valve on a 62 year old man. Both patients are well two years after operation. (3) bilateral pulmonary lesions--11 cases. (4) others--5 cases. Median sternotomy provides less operative loss of lung function, and excellent exposure for selected cases. But these advantages may be lost in some cases in No. (3) when fragile metastatic nodules must be gently manipulated and when an autosuture must be used in different direction for bullae. Whether or not the median sternotomy or posterolateral skin incision is favorable, may be decided by CT findings preoperatively.

Adult↗
PubMed1989

[Problems of diagnosis and surgical treatment in pleural mesothelioma].

Twelve patients with pleural mesothelioma were operated on over a period of 6 years. Two of six patients with localized type died of recurrence. One of two patients showed fibrous form with low grade malignancy and the other showed a mixed type on their histological examination. The remaining 4 patients are alive and well with the combined resection of the tumor and the chest wall for the past 2 to 3 years. Three of six patients with diffuse type had an operation of pleuropneumonectomy with the resection of adjacent structures such as the diaphragm, SVC and the chest wall. One of them who had had the implantation at the chest wall where the biopsy needle entered, developed peritoneal mesothelioma. At laparotomy, numerous nodules were found. He was given 470 mg of CDDP and 80 mg of ADM into the cavity through the tubes. Though this patient died eventually, nodules were found to be macroscopically disappeared at autopsy. But they were left in the area where the drugs could not reach. The other two patients are alive and well for 16 to 22 months after the operation. The remaining 3 patients, who did not have the diagnosis preoperatively, died of cardio-pulmonary insufficiency due to local compression by the huge tumor at 3 months, 7 months and 2 years respectively after the exploratory thoracotomy. It is concluded that wide resection including the rib for a case with solitary lesion and early thoracotomy for a case with undiagnosed chest fluid, followed by pleuropneumonectomy or pleurectomy and post-operative local chemotherapy, are recommended for this malignant disease.

Adult↗
PubMed1988

Unilateral hemispheric cerebral changes similar to Creutzfeldt-Jakob disease in a case of hemiconvulsion.

A 77-year-old man suffered intermittent hemiconvulsions of unknown etiology on the left side for a period of about 5 weeks. At the autopsy, there was marked neuronal loss, severe proliferation of astrocytes and spongiform changes in the right cerebral cortex. The cerebral white matter showed loosening with astroglial proliferation in areas on the same side. These neuropathological changes were slight or absent in the left cerebral hemisphere. Histopathological changes were similar to those seen in unilateral Creutzfeldt-Jakob disease (CJD). Although unilateral CJD can not be ruled out, these unilateral hemispheric changes might be induced by intermittent hemiconvulsions.

Aged↗
PubMed1988

Lewy bodies are ubiquitinated. A light and electron microscopic immunocytochemical study.

The nature of Lewy bodies (LBs) in the brain stem and cerebral cortex in five cases of diffuse Lewy body disease and one case of Parkinson's disease with dementia were investigated immunocytochemically with various antibodies to cytoskeletal proteins, paired helical filaments (PHF) and ubiquitin. Antibodies to 200-kDa component of neurofilament, tau and PHF showed no significant reactions with most of LBs. Antibodies to high-molecular weight microtubule-associated proteins (HMWMAPs) moderately stained the periphery of a few of LBs. A monoclonal antibody to PHF (DF2) which recognizes ubiquitin, and polyclonal antibodies to ubiquitin immunostained virtually all of the typical and cortical LBs as intensely as Alzheimer's neurofibrillary tangles and senile plaque neurites: the periphery of LBs was darkly stained, whereas the central core of typical LBs and central zone of cortical LBs were less intensely stained or remained unstained. Immunoelectron microscopy of the LBs with DF2 revealed that immune reaction products were located on the filaments exclusively in the periphery of LBs, but not on those in the center. These findings suggest that both types of LBs are immunocytochemically indistinguishable despite some structural differences, and that peripherally located filaments in LBs are tagged with ubiquitin, an element required for the ATP-dependent proteolysis system in the cell. Antibodies to ubiquitin are the most useful marker of LBs ever known.

Aged↗
PubMed1988

Mesangiolysis in diabetic glomeruli: its role in the formation of nodular lesions.

In order to elucidate a participation of the mesangiolysis in the formation of diabetic nodular lesions, 355 kidney specimens obtained from 327 patients with primary diabetes mellitus were studied. Mesangiolyses begun by focal and segmental disintegration of the pivotal structure of the mesangium ("torn off phase"), resulting in cystic or aneurysmal dilatation of the involved tuft, were found in 56 specimens (16%). The dilated tufts were filled with lysed mesangial matrix, which showed a reticular or fibrillar arrangement ("structureless phase"), being followed by a concentrical re-arrangement ("reconstructive phase") and by the ultimate formation of diabetic nodules. The mesangiolysis of various phases was frequently found concomitant with severe diabetic arteriolosclerosis and, in the reconstructive phase, the lysed mesangial matrix near the recanalized capillary along the inner aspect of glomerular basement membrane was observed to be rearranged in a layered structure. These results suggest the hypothesis that: 1) the mesangiolysis is the initial lesion occurring in glomeruli in the process of diabetic nodule formation, and disturbed blood flow into glomeruli, caused by diabetic arteriolosclerosis, may be implicated in the development of the mesangiolysis; and 2) concentric compression of the lysed mesangial matrix by recanalized capillaries forms layered structures and ultimate completed diabetic nodules.

Diabetes Mellitus, Type 1↗
PubMed1988

Brain renin-angiotensin system and the hypothalamic, digitalis-like Na+, K+-ATPase inhibitor in rats.

Since angiotensin (ang) II blockers attenuate the centrally-induced pressor responses to a Na+, K+-ATPase inhibitor, ouabain, a brain renin-ang system is assumed to be involved in this pressor mechanism. Centrally-induced pressor responses to hypertonic saline were also blocked with ang II blockers. Thereby, the increase in the plasma level of digoxin-like immunoreactivity was abolished with simultaneous infusions of an ang II analogue or atrial natriuretic polypeptide (ANP). These results indicate that the pressor responses to sodium salts are mediated via inhibition of the brain Na+, K+-ATPase, and that the brain renin-ang system is involved in this mechanism. We noted the existence of a digoxin-like immunoreactive substance (DLI) containing neurons in the hypothalamus (PVN, SON) with the fibers densely distributed in the AV3V area including OVLT, SFO and the median eminence, an area where receptors for ang II are also distributed (1,2). Since pressor responses to intracerebroventricular (ICV) infusions of hypertonic NaCl are abolished with ICV pretreatment with ang II blockers, a brain renin-ang system may be involved in this mechanism. We then searched for a possible relationship between the central effects of NaCl, a brain renin-ang system and an endogenous Na+, K+-ATPase inhibitor in the hypothalamus.

Animals↗
PubMed1988

Hypothalamic digitalis-like substance is released with sodium-loading in rats.

Role of the hypothalamic digitalis-like substance (EDLS) on the hypertension associated with an excess intake of sodium and the releasing mechanism were investigated. The blood pressure in rats fed with a sodium diet increased significantly after 4 weeks of the treatment compared to the control rats fed with a regular diet, which was accompanied by increased urinary output of the EDLS. Electrical lesions of the AV3V area in the hypothalamus significantly decreased both the urinary EDLS level and the blood pressure elevated by the sodium-loading. With the immunohistochemistry using digoxin antibody, the immunoreactives were localized in the neurons of paraventricular and supraoptic nuclei and some other hypothalamic areas, and were also seen in the nerve fibers distributed in the basal hypothalamus, infundibulum, and pituitary posterior lobe. Assuming that the CSF sodium is responsible for the release of EDLS, hypertonic NaCl (2.5 M) was infused into the lateral ventricle for 30 minutes. Blood pressure increased gradually, attaining peak rises about 30 minutes later. The plasma content of the EDLS was significantly greater in the hypertonic NaCl group than the control group treated with either the artificial CSF or 2.5 M of urea solution. On the other hand, the hypothalamic content decreased with the infusion of the hypertonic saline. Furthermore, the continuous intracerebroventricular infusions of the hypertonic NaCl with osmotic minipumps in conscious rats significantly increased the arterial pressure after 6 days. Thereby, the plasma level of the EDLS was significantly greater than the control rats that received only the artificial CSF.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Endogenous digitalislike substance in an adult population in Japan.

Possible involvement of an endogenous digitalislike substance (EDLS) in blood pressure regulation was investigated using a Japanese population. Mean arterial pressure (MAP) significantly correlated with urinary excretion of the EDLS, age, and the obesity index. The plasma EDLS correlated with urinary EDLS. Urinary EDLS excretion well correlated with the inhibitory activity on Na+,K+-ATPase, and also with the urinary excretion of NaCl. Obesity index correlated with the Na+,K+-ATPase inhibition and arterial pressure. Although plasma content of atrial natriuretic polypeptide correlated with the urinary Na+,K+-ATPase inhibition, it did not correlate with the rest of all parameters. Plasma vasopressin level did not correlate with these parameters either. These results clearly indicate that the circulating EDLS (ie, Na+,K+-ATPase inhibitor) is implicated in the hypertension associated with an excess intake of sodium, aging and obesity.

Adult↗
PubMed1988

Vasopressor responses and hyperthermia by intracerebroventricular injections of penicillin, a pyrogen, in rats: involvement of brain angiotensin II.

Because hypothalamus is a center for both the blood pressure and thermoregulation, we assumed that there is a close interrelationship between them. To prove this hypothesis, effects of intracerebroventricular (ICV) injections of a pyrogen, penicillin-G (Pc), on the blood pressure and rectal temperature (RT) were investigated. The ICV injections increased the mean arterial pressure (MAP), heart rate (HR) and the abdominal sympathetic activity (SNA) dose-dependently in urethane-anesthetized rats. In conscious rats, Pc (100 U) elicited the two components of rises in MAP (+19 +/- 1 and +20 +/- 1 mm Hg), and both the RT and HR increased corresponding to the second phase of MAP responses (+1.0 +/- 0.1 degree C and +60 +/- 7 beats/min). ICV injections of an angiotensin II (ang II) antagonist significantly decreased the MAP (-30 +/- 4 mm Hg), HR (-106 +/- 13 beats/min), and the RT (-0.9 +/- 0.1 degree C). ICV injections of Pc elicited drinking behavior (the vehicle group; 1.1 ml/90 min vs Pc group; 8.6 ml) in rats water-deprivated for 24 hours. In spontaneously hypertensive rats (SHRs), ICV injections of Pc elicited augmented responses in the first phase but diminished in the second pressor phase. ICV injections of an ang II antagonist elicited augmented effects in both the MAP (-39 +/- 1 mm Hg) and RT (-0.8 +/- 0.1 degree C) in SHRs. Thus, RT fluctuated corresponding to the blood pressure level in the latter phase, where a brain ang II mechanism may be involved.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1988

Retardation of the development of hypertension in DOCA salt rats by taurine supplement.

To study the antihypertensive effect of orally administered taurine in DOCA salt hypertension, urinary excretion of catecholamines, electrolytes, and arg-vasopressin was measured over four weeks in 20 taurine treated DOCA rats (group 1), 20 taurine untreated DOCA rats (group 2), and seven taurine untreated sham operated rats (group 3). Additional experiments were performed to determine whether or not the pressor and sympathetic responses to hypothalamic stimulation were altered after taurine treatment in DOCA rats. Systolic blood pressure decreased significantly in group 1 after the first week compared with that in group 2, and the differences became progressively more evident thereafter. At the fifth week the mean blood pressure was significantly lower in group 1 than in group 2, as was the heart rate. Although urinary excretion of adrenaline decreased significantly in group 1 at the first and fourth weeks, the difference in urinary excretion of noradrenaline between groups 1 and 2 was not significant. Urinary excretion of adrenaline and noradrenaline in group 3 was significantly lower than that in both hypertensive groups (groups 1 and 2). Urinary sodium excretion increased significantly in group 1 at the first and second week compared with group 2. With graded electrical stimulation of the ventromedial hypothalamus, resulting pressor and sympathetic responses were significantly smaller in group 1 than in group 2. These results suggest that the hypotensive effects of orally administered taurine in DOCA hypertensive rats are caused by suppression of the peripheral sympathetic nervous activity and by the resulting natriuresis.

Animals↗
PubMed1988

Digitalis-like substance is produced in the hypothalamus but not in the adrenal gland in rats.

We studied the role of the adrenals on the plasma levels and urinary output of the digoxin-like immunoreactivity in order to elucidate the interrelationship between the adrenals and hypothalamic digoxin-like immunoreactivity. Urine was collected for 24 h 6 days after the bilateral adrenalectomy and then rats were killed by decapitation. Urinary excretion of digoxin-like immunoreactivity did not differ significantly between the sham-operated and adrenalectomized groups, regardless of sodium intake. Plasma levels did not change significantly with sodium-loading, and adrenalectomy did not significantly affect the plasma concentrations of the immunoreactivity. However, bilateral adrenalectomy increased the content of digoxin-like immunoreactivity in the hypothalamus significantly in both rat groups fed with a regular (P less than 0.05) and a high-salt (P less than 0.02) diet. However, when the levels were measured only 16 h after bilateral adrenalectomy, both plasma and hypothalamic contents were significantly higher in the high-salt than the regular-salt group. The correlation between the plasma and hypothalamic content was significant (P less than 0.01). These results strongly suggest that digoxin-like immunoreactivity is produced in the hypothalamus but not in the adrenals, and that the adrenal glands influence the turnover of the hypothalamic endogenous digitalis-like substance.

Adrenal Glands↗
PubMed1988

Salt increases blood pressure with biphasic changes in hypothalamic responsiveness in rats.

Tail-cuff systolic pressures became elevated in male Wistar rats fed chow containing 8% NaCl for 4 weeks. After 4 weeks of salt loading, pressor and sympathetic responses to ventromedial hypothalamic stimulation were larger in salt-loaded rats. When similar experiments were done following sinoaortic denervation, all of the effects previously induced by dietary salt loading persisted. By contrast, after only 1 week of salt loading, pressor and sympathetic responses to hypothalamic stimulation were reduced, instead of being increased. Since circulating plasma volume was increased in week 1, it was considered possible that reduced hypothalamic responsiveness was due to enhanced cardiopulmonary baroreflexes. Supporting this interpretation, bilateral vagotomy reversed the hypothalamic inhibition occurring in week 1. Although neither the site nor mechanism causing sympathetic hyperactivity has been determined, our results indicate that chronic dietary salt loading has biphasic effects on the ventromedial hypothalamus: an initial inhibition in the first week followed by stimulation thereafter. These results could mean that dietary salt loading eventually increases sympathetic activity and thereby induces hypertension by stimulating the ventromedial hypothalamus.

Animals↗
PubMed1988

Changes in spontaneous firing patterns of rat hippocampal neurones induced by volatile anaesthetics.

1. The effects of the volatile anaesthetics, halothane, isoflurane and enflurane, on rat hippocampal CA1 and CA3 neurones in in vitro preparations were studied by intracellular recording methods. 2. The three anaesthetics, at concentrations similar to those used clinically (0.2-1.2 mM), initially increased and then subsequently decreased the spontaneous firing of CA1 neurones without affecting the resting membrane properties or the EPSPs evoked by focal stimuli. 3. The anaesthetics at these concentrations depressed both the fast after-hyperpolarization of the soma spike and the post-tetanic hyperpolarization induced by repetitive stimulation. They also decreased the IPSPs evoked by focal stimuli. 4. The threshold for spike generation was gradually elevated by as much as 4-6 mV during application of the anaesthetics at these concentrations. The subthreshold potential oscillations (which are likely to be associated with periodic alterations in non-inactivating Ca2+ and Na+ currents) were enhanced in the low concentrations (0.2-0.5 mM), but were depressed in the high concentrations (0.8-1.2 mM). 5. The results suggest that the transient increase in the firing frequency was caused by a depression of both the spike after-hyperpolarization and the post-tetanic hyperpolarization, and that the reduction of spontaneous firing was mainly due to an elevated threshold for spike generation. 6. The three anaesthetics altered the pattern of spontaneous spike-firing in CA3 neurones from solitary spiking to burst firing without affecting the resting membrane properties. 7. The effects of the anaesthetics on the active membrane properties and the postsynaptic potentials in CA3 neurones were similar to the effects in CA1 neurones. 8. In the majority of CA3 neurones, soma spikes elicited by depolarizing current pulses were followed by a Ca2+-dependent after-depolarization, which was in turn followed by a prolonged after-hyperpolarization (post-burst hyperpolarization). The anaesthetics facilitated the after-depolarizing potential, while they depressed the post-burst hyperpolarization. Combination of the two effects would give rise to the highly stereotyped burst (about 1 Hz in frequency) in the presence of the volatile anaesthetics.

Action Potentials↗