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Biomedical subjects

H Koh

Publications and source records attributed to H Koh.

100 records · Page 6Linked to original sources
PubMed1982

Changes of glandular kallikrein activity in human plasma following glucose ingestion.

We studied the changes of glandular kallikrein activity in plasma of nine normal female volunteers, aged 22.2 +/- 1.20 years (mean +/- SEM), following 75 g glucose ingestion along with those of immunoreactive insulin, C-peptide immunoreactivity, free fatty acid and blood glucose using our recently developed assay system for plasma glandular kallikrein activity. Glandular kallikrein activities decreased initially from mean baseline level and then returned to baseline level with the lapse of time after glucose load. Furthermore, in hyperinsulinemic group, mean glandular kallikrein activities at 120 min after glucose load revealed to be significantly higher than those of normoinsulinemic group. The findings suggest that active glandular kallikrein is consumed and utilized during glucose uptake at the peripheral tissues, and hyperinsulinemia brings about prolonged activation of kallikrein-kinin system.

Adult↗
PubMedDate not supplied

VIPergic innervation of diabetic pancreas in rats.

Morphological, ultrastructural, and immunocytochemical studies of nerves containing vasoactive intestinal peptide (VIP) are described in diabetic pancreas of rats after streptozotocin treatment. The observations covered 48 hours and 6 months following streptozotocin treatment. At the ultrastructural level, degenerative changes were already observed in axons of nerve ganglia in the pancreas 48 hours (early stage) after streptozotocin treatment. These changes were hardly detected at the light microscopic level and VIP-like immunoreactivities were seen in nerves and fibers in such pancreas. The nerve ganglia were almost absent in the diabetic pancreas 6 months after streptozotocin treatment (late stage). Associated with the absence of nerve ganglia, nerves and fibers containing VIP-like immunoreactivities were also absent at this late stage. The findings indicated that the changes in the diabetic pancreas were neuropathic caused by metabolic disturbance after long standing diabetes and resulting absence of VIP-like immunoreactive nerves occurred. It was suggested from the present study that the changes in nerve ganglia began as damage at the ultrastructural level due to acute toxicity of the chemical at an early stage and then developed destruction and absence at a late stage.

Animals↗
PubMedDate not supplied

The role of oxidative stress in the pathogenesis of age-related macular degeneration.

Age-related macular degeneration (AMD) is the leading cause of blind registration in the developed world, and yet its pathogenesis remains poorly understood. Oxidative stress, which refers to cellular damage caused by reactive oxygen intermediates (ROI), has been implicated in many disease processes, especially age-related disorders. ROIs include free radicals, hydrogen peroxide, and singlet oxygen, and they are often the byproducts of oxygen metabolism. The retina is particularly susceptible to oxidative stress because of its high consumption of oxygen, its high proportion of polyunsaturated fatty acids, and its exposure to visible light. In vitro studies have consistently shown that photochemical retinal injury is attributable to oxidative stress and that the antioxidant vitamins A, C, and E protect against this type of injury. Furthermore, there is strong evidence suggesting that lipofuscin is derived, at least in part, from oxidatively damaged photoreceptor outer segments and that it is itself a photoreactive substance. However, the relationships between dietary and serum levels of the antioxidant vitamins and age-related macular disease are less clear, although a protective effect of high plasma concentrations of alpha-tocopherol has been convincingly demonstrated. Macular pigment is also believed to limit retinal oxidative damage by absorbing incoming blue light and/or quenching ROIs. Many putative risk-factors for AMD have been linked to a lack of macular pigment, including female gender, lens density, tobacco use, light iris color, and reduced visual sensitivity. Moreover, the Eye Disease Case-Control Study found that high plasma levels of lutein and zeaxanthin were associated with reduced risk of neovascular AMD. The concept that AMD can be attributed to cumulative oxidative stress is enticing, but remains unproven. With a view to reducing oxidative damage, the effect of nutritional antioxidant supplements on the onset and natural course of age-related macular disease is currently being evaluated.

Aging↗
PubMedDate not supplied

A 1-year follow-up study on the effect of atenolol on serum beta 2-microglobulin level in hypertensive diabetic patients.

Hypertensive diabetic patients are particularly prone to renal function impairment. A total of nine out-patients with diabetes and hypertension were, therefore, entered into this single-blind uncontrolled study on the effects of 50 mg/day atenolol on reducing blood pressure and preserving normal kidney functioning. Treatment and evaluations were continued for 12 months. Serum beta 2-microglobulin concentration was used as the index for measuring renal impairment. Atenolol significantly reduced heart rate, systolic and diastolic blood pressure, and serum beta 2-microglobulin concentrations compared with baseline. Plasma glucose and glycosylated haemoglobin levels were unchanged, and blood urea nitrogen levels were increased slightly (non-significant). Serum creatinine showed a tendency (non-significant) to reflect the changes in beta 2-microglobulin concentration. Ways in which atenolol may act to improve kidney functioning are suggested. It is concluded that atenolol is a favourable choice for the treatment of hypertension in diabetic patients with normally functioning kidneys since, even in long-term use, normal renal functioning is preserved.

Atenolol↗
PubMedDate not supplied

Shear bond strength of repaired composite resins using a hybrid composite resin.

The shear bond strength of different types of composite resins repaired with a hybrid composite was evaluated. The hybrid composite resin was repaired with itself as a control. The results of this study showed that the shear bond strength of the repair with most types of composite resins was minimally adequate.

Analysis of Variance↗
PubMedDate not supplied

Serum hyaluronate predicts response to interferon-alpha therapy in patients with chronic hepatitis C.

BACKGROUND/AIMS: The response to interferon therapy for chronic hepatitis is known to decrease with progression of the hepatic fibrosis. On the other hand, serum hyaluronate reflects hepatic sinusoidal capillarization or liver cirrhosis, and also serum type IV collagen, which is one of the main components of the basement membrane, rises with the progression of hepatic fibrosis. In this study, the relationship between the degree of hepatic fibrosis and the response to interferon-alpha was determined retrospectively in patients with chronic hepatitis C. In addition, whether the measurement of serum hyaluronate and type IV collagen before interferon-alpha therapy was useful for predicting the response to interferon-alpha therapy in chronic hepatitis C was determined. MATERIALS AND METHODS: Thirty-seven patients with elevated serum ALT levels for at least 6 months and histologically determined chronic hepatitis were studied. All patients were positive for anti-HCV and negative for hepatitis B surface antigen. Twenty-eight healthy adults with normal blood biochemical data, who were negative for hepatitis B antigen and HCV antibody tests, had limited alcohol intake were used as controls. The test group was given IFN-alpha by intramuscular injection for 14 days, and then were treated 3 times per week for 24 weeks. RESULTS: The extent of hepatic fibrosis, particularly, perisinusoidal fibrosis (P < 0.01) was significantly greater in nonresponders than in responders. The mean serum hyaluronate and type IV collagen levels were more elevated in nonresponders than in responders, especially, the serum hyaluronate level showed a significant difference (P < 0.01). Most of the patients having a serum hyaluronate level of more than 100 ng/ml were nonresponders who had chronic active hepatitis with bridging necrosis on liver biopsy. Serum hyaluronate and type IV collagen levels showed significant positive correlation with degree of the portal fibrosis (P < 0.01), perisinusoidal fibrosis (P < 0.001) and focal necrosis (P < 0.01) in histological findings of liver biopsy specimens. CONCLUSION: These results suggest that serum hyaluronate and type IV collagen levels reflect the extent of the hepatic fibrosis in chronic hepatitis C and also that serum hyaluronate level predicts the response to interferon-alpha therapy in patients with chronic hepatitis C.

Adult↗