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Biomedical subjects

Z Ota

Publications and source records attributed to Z Ota.

At least 19 recordsLinked to original sources
PubMed1992

The magnocellular arginine-vasopressin mRNA responds differently to food deprivation between the supraoptic and paraventricular nuclei of the hypothalamus in adrenalectomized rats with low corticosterone replacement.

We previously reported that food deprivation significantly decreased arginine-vasopressin (AVP) mRNA levels in the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus and also greatly stimulated the pituitary-adrenocortical system in rats. In this study, we deprived adrenalectomized rats with subcutaneously implanted low-dose corticosterone pellets (ADX + B) of food for 3 days to investigate the involvement of corticosteroid feedback regulation in the food deprivation-induced decrease in AVP mRNA in both the SON and the PVN. The plasma corticosterone levels in these animals were maintained at low levels constantly over 24 h. The ACTH concentration in the morning plasma was markedly increased in the food-deprived ADX + B rats as compared to the fed ADX + B rats. Food deprivation significantly decreased the corticotropin-releasing hormone (CRH) content in the median eminence and increased the CRH and AVP content in the neurointermediate lobe of the pituitary. Semiquantitative in situ hybridization histochemistry revealed that AVP mRNA levels were decreased in the SON but, inversely, increased in magnocellular as well as parvocellular subdivisions of the PVN following food deprivation. These results suggest that: (1) AVP mRNA responds differently to food deprivation between the SON and the PVN; (2) the glucocorticoid feedback can exert on AVP mRNA in the PVN but not in the SON in the food-deprived rats; and (3) food deprivation affects the neurohypophysial levels of CRH and AVP.

Adrenalectomy↗
PubMed1992

Glomerular extracellular matrices in rat diabetic glomerulopathy by scanning electron microscopy.

Characteristic pathological changes in the glomeruli in diabetic nephropathy include expansion of the mesangial matrix and thickening of the glomerular basement membrane (GBM). Using an acellular digestion technique combined with scanning electron microscopy, the three-dimensional ultrastructural changes in glomerular extracellular matrices were studied in rats with diabetic glomerulopathy. Diabetes was induced by the intravenous injection of streptozotocin and morphological analyses were performed 3, 6 and 11 months after the injection. Expansion of mesangial area and GBM thickening became evident with time. After treatment with the series of detergents, all cellular components were completely removed leaving the extracellular matrices intact. In normal controls, the mesangial matrix appeared as fenestrated septa with oval or round stomata between the glomerular capillaries. In diabetic glomerulopathy, expansion of mesangial matrix and narrowing of the mesangial fenestrae were observed. These changes in the mesangial matrices seem to play a vital role in the progression of glomerulosclerosis in rat diabetes. A subendothelial thin layer of the GBM was continuous with the mesangial matrix. One cause of GBM thickening in streptozotocin diabetes may be expansion of the mesangial matrix into the peripheral GBM.

Animals↗
PubMed1992

Central interaction between endothelin and brain natriuretic peptide on vasopressin secretion.

OBJECTIVE: To examine the interaction between i.c.v. administration of endothelin and brain natriuretic peptide (BNP) on vasopressin (AVP) secretion in unanesthetized, freely moving rats. METHODS: I.c.v. cannulation and femoral artery catheterization were performed 7-8 days and 2 days before the experiment, respectively. Endothelin and BNP were injected into the third ventricle through the guide cannula. One millilitre of blood was collected for AVP measurement 30 min before and 10 min after i.c.v. injection. RESULTS: Central administration of endothelin (20 or 40 pmol/2 microliters) dose-dependently evoked the elevation of plasma AVP levels. Preinjection of BNP (0.2 or 1 nmol/3 microliters, i.c.v.) dose-dependently attenuated central endothelin (40 pmol/2 microliters)-induced plasma AVP secretion. CONCLUSIONS: We have already reported that BNP attenuated central endothelin-induced pressor response and plasma catecholamine secretion. Taken together, the results indicate that BNP attenuated central endothelin-induced pressor response, at least partially, by suppressing sympathetic nervous system activation and plasma AVP secretion.

Animals↗
PubMed1992

A case of nephrotic syndrome and renal dysfunction in a pregnant woman with diabetes mellitus.

A 29-year-old diabetic woman who developed severe anaemia, nephrotic syndrome, and hypertension before the 28th week of gestation, had residual evidence of toxaemia and renal dysfunction more than 1 month following delivery. The histopathological findings of renal biopsy specimens were considered most consistent with toxaemia of pregnancy complicated by diabetic glomerulosclerosis. We consider that rapid acceleration of renal dysfunction may have been induced by: (1) poor control of diabetes before pregnancy; (2) glomerular hyperfiltration of the remnant nephrons throughout pregnancy; (3) hypercoagulopathy associated with pregnancy; (4) appearance of hypertension following these three conditions.

Adult↗
PubMed1992

Serum and urinary concentrations of type IV collagen and laminin as a marker of microangiopathy in diabetes.

Serum and urinary concentrations of type IV collagen and laminin were measured by enzyme-linked immunosorbent assay (ELISA) in diabetic patients and compared with normal control subjects. In diabetic patients with proteinuria or with renal insufficiency, serum and urinary concentrations of type IV collagen were higher than those of control subjects (p less than 0.005). Furthermore urinary concentrations of type IV collagen and laminin were significantly higher in diabetes, even in the absence of nephropathy, than in normal controls (p less than 0.05). Urinary concentrations of type IV collagen in patients with diabetes and microalbuminuria (0.73 +/- 0.11 mg mmol-1) were significantly higher than in diabetic patients without nephropathy (0.40 +/- 0.060 mg mmol-1) (p less than 0.025). Urinary concentrations of type IV collagen may have a role as an indicator of early diabetic nephropathy. Serum concentrations of type IV collagen in diabetic patients with retinopathy were significantly higher than in normal controls (p less than 0.025). However, urinary concentrations of type IV collagen (p less than 0.05) and serum concentrations of laminin (p less than 0.025) were significantly higher in diabetic patients than normal controls and the difference between patients with and without retinopathy was not significant.

Albuminuria↗
PubMed1992

Heparan sulfate proteoglycans are lost in patients with diabetic nephropathy.

The pathogenesis of diabetic nephropathy relative to the changes in the glomerular extracellular matrices was investigated. Renal tissues from 10 diabetic patients were immunostained with antibodies directed against heparan sulfate proteoglycans (HS-PGs), laminin, type IV collagen and fibronectin. Seven patients were nephrotic and had advanced glomerulosclerosis with nodular lesion, while the other 3 had no renal manifestations or minor glomerular tissue alterations. Controls included kidneys removed from patients with renal tumors and specimens obtained by renal biopsy from patients with IgA nephropathy. Relationships among proteinuria, intensity of fluorescence and glomerular changes were studied. In diabetes 3 patients with minor glomerular lesions were found to have no changes in various components of extracellular matrices. A marked reduction in the intensity of staining with anti-HS-PG antibodies was observed in renal specimens from patients with nodular glomerulosclerosis and proteinuria, while a mild decrease in the intensity of fluorescence was observed in tissues stained with antilaminin antibodies. An increase compared to normal control sample findings in type IV collagen and fibronectin was observed in the mesangium of sclerosing glomeruli. No loss of HS-PG was observed in patients with IgA nephropathy. These results indicate that glomerular extracellular matrix HS-PG is lost in association with diabetic nephropathy; this loss results in alteration of the charge-selective properties of glomerular capillaries. This alteration may, in part, be the cause of the proteinuria associated with diabetic nephropathy.

Adult↗
PubMed1992

Development of a simple spasticity quantification method: effects of tizanidine on spasticity in patients with sequelae of cerebrovascular disease.

A simple method that can be performed at the bedside using a spring balance was developed in order to quantify spasticity. The effects of tizanidine on spasticity were evaluated in 30 patients with sequelae of cerebrovascular disease using this method. Treatment with tizanidine was effective in 60% of the patients; there were high correlations between spasticity before and after tizanidine administration and the severity of symptoms and also between the degree of improvement in spasticity and in that of the symptoms. Atonic seizures, due to overdose of tizanidine, were observed in only one patient. The simple spasticity quantification method developed was useful for monitoring tizanidine administration in order to prevent drug overdose. The method appears to be very useful for evaluating the degree of spasticity at the bedside and in measuring the effects of antispastic drugs.

Aged↗
PubMed1992

Influence of prostaglandin E1 on slight proteinuria in non-azotaemic diabetics.

In an investigation into the effect of prostaglandin E1 on proteinuria in nephrotic diabetic nephropathy, five patients were treated with 40 micrograms prostaglandin E1 administered intravenously over 2 h twice daily for 4 weeks. The following parameters were compared before and after treatment: protein excretion in urine; total serum protein concentration; serum albumin concentration; creatinine clearance; blood urea nitrogen; and serum creatinine content. A further five patients with nephropathy resulting from non-insulin-dependent diabetes mellitus were selected as controls. Analysis of the results using Student's t-test showed no significant change in any of the parameters before and after treatment.

Adult↗
PubMed1992

Does a dose of 40 micrograms/day prostaglandin E1 reduce creatinine clearance in a patient with diabetic nephropathy of the nephrotic type?

The case history of a woman, who at the age of 25 years on the birth of her second child was found to be diabetic, is reported. Over the subsequent 30 years the patient had been treated with insulin, the dose administered being monitored at regular intervals. At the age of 52 years, the patient was diagnosed as suffering from hypertension and diabetic nephropathy of the nephrotic type. The patient's condition gradually deteriorated and at 55 years of age 40 micrograms/day prostaglandin E1 was given intravenously for 84 days. Treatment resulted in a decline in urinary protein without a reduction in creatinine clearance. Renograms confirmed an improvement in the vascular and secretory phases of both kidneys.

Alprostadil↗
PubMed1992

Age-related changes in cerebrospinal fluid gamma-aminobutyric acid concentration.

The purpose of this study was to clarify the effect of aging on brain gamma-aminobutyric acid metabolism. We measured the cerebrospinal fluid gamma-aminobutyric acid concentration in subjects of various ages, including healthy volunteers and patients without neurological or psychiatric disease. The cerebrospinal fluid gamma-aminobutyric acid concentration was determined by radiolabelled receptor assay using [3H]gamma-aminobutyric acid. Cerebrospinal fluid gamma-aminobutyric acid was significantly higher in the control group (20s and 30s) than in the groups of subjects in their 50s, 60s, 70s and 80s. There was a significant negative correlation between cerebrospinal gamma-aminobutyric acid concentration and age (p less than 0.01). These data suggest that dysfunction of brain gamma-aminobutyric acid metabolism increases with age, and that the various symptoms caused by abnormal gamma-aminobutyric acid metabolism in the brain are therefore more likely to appear in elderly people.

Adult↗
PubMed1992

Mechanism of proteinuria in nephrotic syndrome.

We developed a "tissue negative staining method" to observe the molecular-level ultrastructure in situ in any portion of the ultrathin sections routinely prepared for electron microscopy. This method was used in electron microscopy of the glomerular basement membranes (GBM). The GBM in patients with nephrotic syndrome was discovered to possess a tunnel structure, designated as "nephrotic tunnel", with lumen large enough to allow free passage of protein molecules. This tunnel seemed to be involved in the etiology of nephrotic syndrome. This new method appears to be applicable to a variety of purposes in biological studies.

Animals↗
PubMed1992

Enhanced expression of complement regulatory proteins on thyroid epithelial cells of Graves' disease.

Cytotoxic anti-thyroid microsomal autoantibodies are highly prevalent in sera of patients with Graves' disease, but in Graves' disease thyroid tissues rarely show destructive changes. We postulated that this might be due to membrane-associated complement regulatory proteins which protect target cells from injury by complement activation. We, therefore, investigated the expression of membrane attack complex inhibitory factor (MACIF) and decay accelerating factor (DAF) in the thyroid tissues from patients with Graves' disease, Hashimoto's thyroiditis, thyroid adenocarcinoma and normal human thyroid tissues. We found a high level of expression of MACIF and DAF in Graves' thyroid tissues. Using the membrane immunofluorescence and cell-ELISA techniques, we also investigated the factors which enhanced the MACIF and DAF expression in cultured thyroid cells. Thyroid stimulating hormone, phorbol 12, 13-dibutyrate and thyroid stimulating autoantibody enhanced the MACIF and DAF expression. These findings suggest that the membrane complement regulatory proteins increase in response to the thyroid stimulating factors such as thyroid stimulating autoantibody in Graves' disease and that this increase then protects the cells from damage due to complement activation by thyroid autoantibodies.

Antigens, CD↗
PubMed1992

Frequency of gamma delta T cells in peripheral blood, synovial fluid, synovial membrane and lungs from patients with rheumatoid arthritis.

The percentages and absolute numbers of gamma delta T cells per CD3 positive cells (T cells) in four different compartments, namely peripheral blood, synovial fluid, synovial membrane and lungs from patients with rheumatoid arthritis (RA) and in peripheral blood from healthy controls were studied by two color flow-cytometric analysis. The percentages (mean +/- SEM = 6.3 +/- 0.8%, n = 22) and absolute numbers (70 +/- 11/microliters, n = 22) of gamma delta T cells in peripheral blood from RA patients were not different from those of 22 age-matched healthy controls (7.5 +/- 0.9%, 81 +/- 17/microliters, respectively). The gamma delta T cells in peripheral blood from 50 RA patients were, however, significantly decreased in negative correlation with the value of CRP as a marker for inflammation, although they had no correlation with the titer of rheumatoid factor as an autoantibody. The percentages of gamma delta T cells in synovial fluid from 10 patients (3.3 +/- 0.5%, n = 10) or in synovial membrane from 5 patients (4.2 +/- 1.9%, n = 5) and in bronchoalveolar lavage fluid from 6 patients (3.6 +/- 0.8%, n = 6) were not different from those in peripheral blood from the same patients. Thus, gamma delta T cells are not the dominant infiltrating T cell subset in the inflammatory sites of RA patients.

Adult↗
PubMed1992

Significance of urinary albumin index in the urine collected arbitrarily in the morning.

To evaluate urinary albumin index (UAI), the relationship between albumin excretion rate (AER) in the urine stored for 24 h and UAI in the urine collected arbitrarily on the morning of the same day was studied in 123 inpatients. The patients were admitted to our hospital from September 1, 1988 to August 31, 1989, consisting of 67 non-insulin dependent diabetics (Group 1), 40 patients with collagen disease (Group 2), and 16 patients with primary renal disease (Group 3). The relationship between log(e) AER and log(e)UAI was plotted on a graph. Pearson's rank correlation coefficients of Groups 1-3, Group 1, Group 2, and Group 3 were as follows: r = 0.725, r = 0.691, r = 0.855, and r = 0.611, respectively. The formula obtained by using Pearson's rank correlation coefficients to estimate log(e)AER from log(e)UAI in 123 cases of Groups 1-3, 67 cases of Group 1, 40 cases of Group 2, and 16 cases of Group 3 were: log(e)AER/log(e)UAI = 0.815, log(e)AER/log(e)UAI = 0.860, log(e)AER/log(e)UAI = 0.830, log(e)AER/log(e) = 0.722, respectively. In the present study, log(e)UAI was found to correlate well with log(e)AER. As AER is generally accepted to be the most reliable index to know the stage of albuminuria, UAI is considered to be clinically useful.

Adult↗
PubMed1992

[Chronic administration of lisuride hydrogen maleate increases muscarinic acetylcholine receptor binding in aged rat brain].

Changes in the distribution and densities of muscarinic acetylcholine receptors (mACh-R) in young adult and aged rat brain, and the effects of chronic administration of lisuride hydrogen maleate (lisuride) on these changes were studied by in vitro quantitative autoradiography of [3H] quinuclidinyl benzilate binding. mACh-R was relatively higher in the striatum, hippocampus and cerebral cortex in the young adult rats. In contrast, mACh-R binding was markedly reduced in the striatum, accumbens nucleus, amygdaloid nucleus and frontal cerebral cortex of aged rats compared to young adult rats. However, chronic administration of lisuride significantly increased mACh-R binding in the parietal cerebral cortex as well as in the above-mentioned regions in aged rats. This lisuride-induced increase in mACh-R of aged rat brain is considered to have important implications concerning the mechanism of therapeutic efficacy of lisuride.

Aging↗