Biomedical subjects

F Umeda

Publications and source records attributed to F Umeda.

At least 109 records · Page 6Linked to original sources

PubMed1992

Alterations in femoral bone histomorphometry and vitamin D metabolism in neonatal streptozotocin-induced diabetic rat.

Histomorphometric examination and histological observation of femoral bone were performed on long-standing neonatal streptozotocin-induced diabetic rats (n2STZ, n5STZ) as a human model of non-insulin-dependent diabetes mellitus. The growth and strength of femurs decreased in the STZ diabetic rats. Histomorphometric parameters such as cortical bone thickness, number of metaphysical trabeculae and percent trabecular volume of metaphysical area all significantly decreased in the STZ diabetic rats. There were no significant differences in parameters between the n2STZ and n5STZ diabetic rats. Histological findings demonstrated no significant change in the number of osteoclasts in femur nor change corresponding to osteomalacia. Bone absorption in the STZ diabetic rats appeared unchanged. The plasma calcium level did not change in the STZ diabetic rats, although their plasma phosphate or A1-p levels increased. Circulating 24, 25 (OH)2D3 was significantly lower in the STZ diabetic rats than the controls. However, 25 (OH) D3 or biologically active 1, 25 (OH)2D3 was not different between the controls and STZ diabetic rats. Osteopenia is thus present in the femurs of long-standing neonatal STZ diabetic rats, due in part to abnormal vitamin D metabolism.

Animals↗

PubMed1992

Utility of the latex agglutination nephelometric immunoassay (Albusure Test) in screening for microalbuminuria in patients with diabetes mellitus.

All diabetic patients should be screened for early signs of diabetic nephropathy, because it is a prognostic factor in the disease. The albusure test (AT), a latex agglutination nephelometric immunoassay, is a rapid and low cost test for the detection of microalbuminuria of 30 mg/L or more. We compared the results of AT and of radioimmunoassay (RIA) for urinary albumin to evaluate the clinical utility of AT using fresh urine samples from 74 diabetic patients without persistent proteinuria and from 11 healthy subjects. Urinary albumin levels were 6.0 +/- 2.3 mg/L in the healthy subjects, 11.0 +/- 8.7 mg/L in the AT-negative group (n = 61), and 38.1 +/- 10.2 mg/L in the AT-positive group (n = 13). Using a cut-off value of 30 mg/L by RIA, the rate of coincidence between AT and RIA was 89.2%, although five subjects were false-positive by AT, and three were false-negative. These results show that AT may provide a useful monitor for microalbuminuria, a reliable early marker of diabetic nephropathy.

Adult↗

PubMed1992

[A case of the diabetic nephropathy without hyperglycemia].

We report a case of diabetic nephropathy with impaired glucose tolerance. A 52 year obese woman with nephrotic syndrome and hypertension showed severe and remarkable edema, as her legs were elephantiasis. To be clear the etiology of nephrotic syndrome, we performed renal biopsy. The histological findings of the specimen showed glomerulosclerosis. Additionally the examination of ocular fundus revealed microaneurysm and avascular area. We concluded that diagnosis of this case must be non-insulin-dependent diabetes mellitus.

Diabetes Mellitus, Type 2↗

PubMed1992

Platelet-derived growth factor and growth-promoting activity in the serum samples and platelets of patients with non-insulin-dependent diabetes mellitus.

Although platelet-derived growth factor (PDGF) is thought to be a major mediator of atherosclerotic disease, the pathophysiology of diabetic vasculopathy, including atherosclerosis, is unclear. By means of an enzyme immunoassay that used a monoclonal antibody against human PDGF-B chain, PDGF-like immunoreactivity was determined in serum, platelet-poor plasma, and platelet lysate of 28 patients with non-insulin-dependent diabetes mellitus and 11 control subjects. Growth-promoting activity was also measured by tritiated thymidine incorporation into DNA of cultured human fibroblasts. The PDGF-like immunoreactivity in serum was correlated (r = 0.42; p less than 0.01) with that in platelet lysate prepared from a fixed volume of blood. Furthermore, a correlation (r = 0.70; p less than 0.001) was found between the PDGF-like immunoreactivity and the growth-promoting activity in platelet lysate but not in serum. There was no significant difference between patients with diabetes and control subjects with respect to the PDGF-like immunoreactivity in serum or in platelet lysate (38.2 +/- 2.2 vs 42.8 +/- 3.1 ng/ml or 49.1 +/- 2.4 vs 56.2 +/- 3.4 ng/mg protein; mean +/- SEM). In contrast, the serum growth-promoting activity was lower (p less than 0.05) in patients with diabetes than in control subjects (88.1% +/- 7.1% vs 117.4% +/- 6.9%) and there was a negative correlation (r = -0.39; p less than 0.05) between the serum growth-promoting activity and the fasting plasma glucose level. The growth-promoting activity in platelet lysate of patients with diabetes did not differ from that of the control subjects (59.9% +/- 11.6% vs 65.9% +/- 11.2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗

PubMed1991

Increased intracellular calcium mobilization in platelets from patients with type 2 (non-insulin-dependent) diabetes mellitus.

Enhanced platelet functions have been reported in patients with diabetes mellitus. Our recent study demonstrated that phosphoinositide turnover is increased in platelets from diabetic patients. In the present study, we evaluated the abnormality in platelet intracellular calcium mobilization in patients with Type 2 (non-insulin-dependent) diabetes mellitus using fura-2, a fluorescent calcium indicator. Washed platelets were prepared from six diabetic patients with increased platelet aggregation rates (DM-A group), seven diabetic patients with normal platelet aggregation rates (DM-B group), and eight age-matched healthy control subjects. The basal intracellular free calcium concentrations in platelets were similar among the three groups. Thrombin (0.025-0.1 U/ml) induced a dose-dependent increase in intracellular calcium in both the presence and the absence of extracellular calcium. This increase in the presence of extracellular calcium, which depends on calcium influx and release, was significantly higher in the DM-A group than in the DM-B and control groups. However, there was no significant difference between the control group and the DM-B group. In the absence of extracellular calcium, thrombin-induced calcium increase, which depends only on calcium release, was also significantly enhanced in the DM-A group. Furthermore, the calcium increase stimulated by platelet-activating factor (10 nmol/l) with and without extracellular calcium was significantly higher in the DM-A group than in the other groups. Additionally, calcium ionophore A23187 (100 nmol/l) caused a significantly higher calcium increase in the DM-A group with extracellular calcium, while the calcium increase without extracellular calcium showed no significant difference among the three groups. These observations suggest that enhanced intracellular calcium mobilization due to increased calcium influx and release may be closely related to platelet hyperfunctions in diabetes mellitus.

Analysis of Variance↗

PubMed1991

Increased inositol phosphate accumulation in platelets from patients with NIDDM.

We evaluated thrombin-induced inositol phosphate accumulation in [3H]inositol-labeled platelets prepared from patients with non-insulin-dependent diabetes mellitus. There were no significant differences in [3H]inositol incorporation into and contents of phosphoinositides between the diabetic patients and their age-matched control subjects. Thrombin induced a dose- and time-dependent accumulation of inositol phosphate. The accumulation of [3H]inositol trisphosphate and [3H]inositol bisphosphate by thrombin stimulation were significantly enhanced in platelets from the diabetic patients, although the accumulation of [3H]inositol monophosphate did not differ between the diabetic patients and the control subjects. In addition, the platelet aggregation rate induced by thrombin was also significantly enhanced in the diabetic patients in correlation with the enhanced inositol phosphate accumulation. These results suggest that increased inositol phosphate accumulation may cause accelerated platelet functions in diabetes mellitus.

Blood Platelets↗

PubMed1991

A case of insulin allergy: the crystalline human insulin may mask its antigenicity.

We report an unusual case of insulin allergy. A 48-year-old man with non-insulin-dependent diabetes mellitus receiving biosynthetic isophane human insulin (Humulin N) developed itchy wheal-and-flare reactions at the sites of injection. When Humulin N was changed to a semi-synthetic crystalline human insulin zinc (Novolin U), the allergic reactions completely disappeared. Evaluation of his serum showed a high level of insulin-specific IgE. Skin testing with all commercially available insulins showed immediate local reactions to all agents tested except for Novolin U. In addition, decrystallized Novolin U prepared by lowering the pH with acetic acid also induced a positive reaction. These observations suggest that the crystallized structure of human insulin may mask its antigenicity for allergic reactions.

Diabetes Mellitus, Type 2↗

PubMed1991

Glucose reduces PDGF production and cell proliferation of cultured vascular endothelial cells.

The effect of glucose on PDGF production and cell proliferation was studied on cultured bovine aortic endothelial cells. PDGF levels were measured using an enzyme-linked immunosorbent assay technique newly developed in our laboratory. The cell proliferation rate was determine on the basis of 3H-thymidine incorporation into cellular DNA. PDGF levels in culture medium were below the detection limit of the assay. However, PDGF levels were measurable in cultured endothelial cells at confluence. Both PDGF production and thymidine incorporation were significantly reduced in the endothelial cells cultured with high concentrations of glucose. These results suggest that reduced PDGF production and cell proliferation may be involved in altered vascular endothelial function in diabetics.

Animals↗

PubMed1991

Effects of glucagon-like peptide 1 (7-36) amide and glucagon on amylin release from perfused rat pancreas.

The effects of glucagon-like peptide 1 (7-36) amide [GLP-1 (7-36) amide] and glucagon on the release of islet amyloid polypeptide (IAPP), or amylin, from the isolated perfused rat pancreas were studied. In the presence of 5.6 mM glucose, GLP-1 (7-36) amide and glucagon stimulated the release of amylin from the perfused pancreas. The infusion of GLP-1 (7-36) amide at a concentration of 10(-9) M elicited a biphasic release of amylin similar to that of insulin. The cumulative output of amylin induced by 10(-9)M GLP-1 (7-36) amide was significantly higher than that by 10(-9)M glucagon (p less than 0.01). The amylin/insulin molar ratios induced by GLP-1 (7-36) amide and glucagon were about 1% and did not differ significantly. These findings suggest that GLP-1 (7-36) amide and glucagon stimulate the release of amylin from the pancreas and that the concomitant secretion of amylin and insulin might contribute to glucose homeostasis.

Amyloid↗

PubMed1991

Platelet stimulation for prostacyclin production in aortic endothelial cell cultures: alteration in diabetes mellitus.

We evaluated the effect of platelets on prostacyclin (PGI2) production in bovine aortic endothelial cell cultures. Human platelet extract significantly stimulated PGI2 production by cultured aortic endothelial cells in a time- and dose-dependent manner, suggesting that platelets contain PGI2-stimulatory activity (PSA). Supernatant fluid separated from platelets activated by collagen also exhibited PSA. The factor(s) causing the PSA of platelets was non-dialysable and heat-stable (56 degrees C for 30 min or 100 degrees C for 3 min), was completely inhibited by trypsin pretreatment, and exhibited an affinity to heparin agarose. Furthermore, gel filtration chromatography showed that the factor(s) responsible for the platelet PSA was eluted at three different peaks with approximate molecular weights of 50,000, 25,000 and 11,000. The PSA of platelet extract from patients with non-insulin-dependent diabetes mellitus (NIDDM) (n = 10) was compared to that from age-matched control subjects (n = 10). Platelet extract from patients with NIDDM stimulated cultured aortic endothelial cells to produce greater amounts of PGI2 than did that from control subjects. These data suggest that the increased PSA of platelets isolated from diabetic patients may contribute to the abnormal interaction between platelets and the vascular wall in diabetic patients.

Animals↗

PubMed1991

Haemostatic factors associated with vascular thrombosis in patients with systemic lupus erythematosus and the lupus anticoagulant.

To elucidate the mechanism of vascular thrombosis in patients with systemic lupus erythematosus and the lupus anticoagulant changes in factors associated with haemostasis were investigated. The lupus anticoagulant was associated with an increased incidence of thrombosis, particularly cerebral thrombosis. Concentrations of fibrinopeptide A and fibrinopeptide B beta 15-42 were significantly raised in the plasma of patients with systemic lupus erythematosus and the anticoagulant compared with concentrations in patients without the lupus anticoagulant. The tendency towards formation of thrombosis was not found in all lupus patients with the anticoagulant, however. Concentrations of thromboxane B2 were remarkably raised in the plasma of the two patients with the lupus anticoagulant who had recently had thrombosis. Concentrations of 6-keto-prostaglandin F1 alpha, protein C, antithrombin III, and plasminogen were similar in both groups. No significant decrease in serum stimulatory activity on prostacyclin production by cultured aortic endothelial cells was noted in lupus patients with the anticoagulant, but inhibition was present in the two patients with recent thrombosis. These results indicate that although patients with the lupus anticoagulant are not always in a hypercoagulable state, haemostatic abnormalities found in some patients with the anticoagulant may be predictive of thrombotic events.

6-Ketoprostaglandin F1 alpha↗

PubMed1991

Serum 1,5-anhydro-D-glucitol and glycemic control in patients with non-insulin-dependent diabetes mellitus.

Serum 1,5-anhydro-D-glucitol (AG) levels, which have been reported to decrease specifically in diabetics, were measured in 102 patients with non-insulin-dependent diabetes mellitus (NIDDM). The mean of serum AG levels was 7.9 +/- 0.7 micrograms/ml (mean +/- S.E.). It was found a significant negative correlation between serum AG level and HbA1c or fasting blood sugar level. The decrease in serum AG levels inversely correlated with the extent of glycemic control in the patients with NIDDM. Additionally, the changes of serum AG levels negatively correlated with the changes of HbA1c levels during long-term (2 years) treatment. Furthermore, serum AG levels were compared between the patients with and without diabetic complication such as retinopathy, proteinuria or neuropathy. It was found that each group of the patients with complication had significantly decreased serum AG level compared with the complication free group. On the other hand, however, no differences were found in serum AG levels corrected by HbA1c levels using the linear regression formula between the group of the patients with and without diabetic complication.

Adult↗

PubMed1991

Release of amylin from perfused rat pancreas in response to glucose, arginine, beta-hydroxybutyrate, and gliclazide.

Amylin is a 37-amino acid peptide isolated from the islet amyloid of patients with non-insulin-dependent diabetes mellitus. The isolated perfused normal rat pancreas was used to evaluate the effects of glucose and insulin secretagogues, such as arginine, beta-hydroxybutyrate, and gliclazide, on amylin secretion. Glucose and the other stimulants tested elicited a significant release of amylin from the rat pancreas in a biphasic pattern, similar to that of insulin. Dose-response studies of the glucose-induced release of amylin and insulin revealed that they possessed a similar dependency on glucose. However, the release of amylin induced by high concentrations of glucose was partially dissociated from that of insulin; that is, the amylin-insulin molar ratios induced by 22.2 and 33.3 mM glucose (1.11 +/- 0.05 and 1.05 +/- 0.04%, respectively) were significantly higher than those induced by 16.7 mM glucose (0.90 +/- 0.04%, P less than 0.01 vs. 22.2 mM glucose, P less than 0.05 vs. 33.3 mM glucose). Additionally, when the basal concentration of glucose in the perfusate was increased from 5.6 to 11.1 mM, the response of amylin was unchanged. These data suggest that amylin may be an islet hormone whose abundant response to high concentrations of glucose might contribute to the oversecretion of amylin in the hyperglycemia that accompanies diabetes mellitus.

3-Hydroxybutyric Acid↗

PubMed1991

Cultured bovine endothelial cells convert big endothelin isopeptides to mature endothelin isopeptides.

The incubation of big endothelin-1 (big ET-1), big ET-2 or big ET-3 with cultured bovine endothelial cells (ECs) resulted in their conversions to mature endothelins (ETs). These conversions apparently exhibited Michaelis-Menten kinetics as a function of each big ET isopeptide. The conversions of big ETs were abolished by phosphoramidon. These results indicate that vascular endothelium can convert exogenous big ET-1 to mature ET-1 through a phosphoramidon-sensitive metalloprotease, and that this enzyme has also high affinities for big ET-2 and big ET-3.

Animals↗

PubMed1991

Decreased vasoactive intestinal polypeptide (VIP) level in cerebrospinal fluid from diabetic patients with neuropathy.

The concentration of vasoactive intestinal polypeptide (VIP) was measured in cerebrospinal fluid (CSF) obtained from diabetic patients with neuropathy and their age-matched control subjects. VIP level in CSF from diabetic patients was significantly decreased as compared with that from the controls (12.9 +/- 3.1 pg/ml vs. 35.4 +/- 3.3 pg/ml, p less than 0.01). Decreased VIP level in CSF may relate with diabetic neuropathy in particular sexual dysfunction.

Adult↗

PubMed1990

Enhanced secretion of endothelin-1 by elevated glucose levels from cultured bovine aortic endothelial cells.

We have investigated the effect of glucose on the release of endothelin-1-like immunoreactivity (ET-1-LI) from cultured bovine aortic endothelial cells. Elevation of glucose concentrations in cultured media from 5.5 to 11.1 or 22.2 mM significantly stimulated ET-1-LI release from cultured endothelial cells. An aldose reductase inhibitor did not affect the high glucose-induced ET-1-LI release. These findings suggest the possibility that hyperglycemia in diabetic patients enhances ET-1-LI release at the local site of vascular endothelium, which might be involved in the developments of vascular complications and atherosclerosis.

Animals↗

PubMed1990

Identification and characterization of endothelin converting activity in cultured bovine endothelial cells.

Using a specific and sensitive radioimmunoassay (RIA) for the carboxyl terminal tail of endothelin (ET) (His16-Trp21), we have confirmed the presence of the converting activity from synthetic human big ET-1 to ET-1 in the homogenate of cultured bovine aortic endothelial cells. The optimal pHs for the converting activities were found at pH 3.0 and pH 7.0. The activity at pH 3.0 was completely inhibited by pepstatin A, whereas the activity at pH 7.0 was not affected by known various protease inhibitors except EDTA and EGTA. When the products from big ET-1 were analyzed on an ODS and a CN columns, only ET-1 was detected at pH 7.0, but various ET-like immunoreactivities other than ET-1 were detected at pH 3.0. These findings strongly suggest that mature ET-1 is formed from big ET-1 in the endothelial cells by a metal-dependent neutral protease.

Animals↗

PubMed1990

Modification of prostacyclin-stimulatory activity in sera by glucose, insulin, low density lipoprotein, linoleic acid and linoleic acid hydroperoxide.

Reduced prostacyclin (PGI2) production by the vascular wall has been proposed as one of the possible causes of diabetic vascular complications. We found an activity which stimulated PGI2 production by cultured endothelial cells (PGI2-stimulatory activity, PSA) in human plasma-derived serum (PDS). The PSA was less in patients with diabetes mellitus. The present study was undertaken to evaluate how metabolic factors relevant to diabetic angiopathy modify the PSA. Pooled PDS was prepared from 10 healthy volunteers. The 6-keto-PGF1 alpha (6KF, a stable metabolite of PGI2) production by cultured bovine aortic endothelial cells was maximally stimulated by Dulbecco's modified Eagle's medium (DMEM) containing 10% pooled PDS after incubation for 60 min. The production of 6KF was reduced in a dose-dependent manner by the addition of 10% pooled PDS with glucose and linoleic acid hydroperoxide (lipid peroxide). In contrast, human low density lipoprotein (LDL) and linoleic acid (unsaturated fatty acid) enhanced the production of 6KF by 10% pooled PDS in a dose-dependent manner. Insulin, however, showed no effect on the production of 6KF by 10% pooled PDS. These results suggest that the reduced PSA in diabetics may be the result, in part, of a modification of the PSA by diabetic metabolic factors such as glucose and lipid peroxide.

6-Ketoprostaglandin F1 alpha↗