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Biomedical subjects

D K Yue

Publications and source records attributed to D K Yue.

At least 73 records · Page 4Linked to original sources
PubMed1992

Diabetes education: whose priorities are met?

Two hundred Type 2 diabetic patients newly referred to the diabetes centre at a large university teaching hospital were studied over an 8-month period. Patients completed a diabetes knowledge questionnaire, and specified their educational priorities by selecting six diabetes-related topics from a list of 14. After giving 1 h of individual education and using the same list, the educators selected six topics which they considered to be most important for that particular patient to know. Choice of educational priorities differed between the patients and the corresponding educator (p less than 0.001). In only 38% of cases did the educators' first three priorities coincide with those of the patients. The major discrepancies were in the selection of 'sick day management' and 'complications', especially favoured by patients, as against 'oral hypoglycaemic agents' and other therapy-related topics, especially favoured by educators. Diabetes knowledge was a determinant of educational priority for patients (p less than 0.001) but not educators. In contrast, only the educators' overall choices were affected by duration of diabetes (p less than 0.001). Diabetes treatment type influenced both patients' and educators' selection of priorities (p less than 0.001). We conclude that an educational strategy which relies on health professionals' perceptions to determine what diabetic patients need to know may be inadequate.

Blood Glucose↗
PubMed1991

Interaction between diabetic patients, their general practitioners and a hospital diabetic clinic.

OBJECTIVE: The aim of this study was to examine the sociodemographic data of diabetic patients referred to our clinic and to correlate these with characteristics of their individual general practitioners. How these factors affect the interaction between patients, general practitioners and a hospital diabetic clinic was evaluated. DESIGN: Prospective recruitment of consecutive referrals. SETTING: The diabetic clinic of a teaching hospital located in the inner city suburbs of Sydney. PATIENTS: Two hundred and forty-six patients with diabetes (10% insulin dependent), aged 20-86 years, participating in our Shared Care Project, a randomised controlled study on various methods of following up diabetic patients. INTERVENTIONS: Data for the study were gathered by interview and questionnaire during first assessment at the clinic. MAIN OUTCOME MEASURES: Clinical and sociodemographic characteristics of patients; the location of general practitioners, their diagnostic equipment and type of practice; and the level of detail recorded in referral letters from general practitioners. RESULTS: Diabetic patients of migrant background who cannot speak English are older and have less formal education. They see their doctors more often and seek out general practitioners who speak their language, even if it means travelling longer distances. Patients referred from 24 hour medical centres are younger, more educated and have less contact with their doctors both in duration and frequency of visits when compared with patients whose general practitioners operate in conventional sole or partnership practices. Many patients have more than one general practitioner, making communication with hospitals difficult. In their referral letters, general practitioners usually concentrate on hypertension, hypercholesterolaemia and metabolic aspects of diabetes, but under-emphasise diabetic complications; they make insufficient use of measurement of the glycosylated haemoglobin level to assess diabetic control while over-using glucose tolerance testing in making the diagnosis. The referral letter often does not contain enough information to help clinical decision making. CONCLUSIONS: Demography of patients and characteristics of general practitioners are important factors which can affect their interaction with public hospitals. Bearing in mind the work load of general practitioners and the diverse nature of patients, hospitals must implement systems which make it easier for general practitioners and patients to interact with them.

Adult↗
PubMed1991

Changes in hepatic glutathione metabolism in diabetes.

Glutathione is important in the regulation of the redox state, and a decline in its tissue level has often been considered to be indicative of increased oxidative stress in diabetes. In this study of diabetic rats, the level of hepatic glutathione was normal unless food intake was restricted. Thus, the previous report of a reduction in hepatic glutathione in diabetes is likely to be the result of food deprivation rather than diabetes alone. In contrast to changes characteristic of oxidative stress, the efflux of glutathione in bile from diabetic animals was significantly decreased, whereas hepatic mixed disulfides were unchanged, and the hepatic gamma-glutamyltransferase activity was considerably increased. These changes were not reproduced by food deprivation. The decrease in biliary excretion of glutathione in diabetes may reflect an attempt to conserve glutathione by activation of the hepatic gamma-glutamyl cycle. We conclude that the disturbances of glutathione metabolism in diabetes are not typical of those seen in oxidative stress or food restriction.

Animals↗
PubMed1991

Interaction of ascorbic acid and glucose on production of collagen and proteoglycan by fibroblasts.

Collagen and proteoglycans are two major constituents of the extracellular matrix, and their abnormalities have been incriminated in the pathogenesis of diabetic complications. A decrease of plasma ascorbic acid has been reported in diabetes and thus may play a role in the collagen and proteoglycan abnormalities in diabetes. Ascorbic acid and glucose share structural similarity, and their metabolism may interact at the level of membrane transport and cellular action. In this study, we used a fibroblast culture system to explore this possibility. Ascorbic acid increased collagen and proteoglycan both in the culture medium and the cell layer. This stimulatory action of ascorbic acid was inhibited by the presence of glucose at a concentration of 25 mM. The effect of high glucose concentration was not mediated by inhibition of ascorbic acid uptake by fibroblasts. Insulin is able to abolish this inhibitory action of glucose on collagen production, but the precise mechanism is unclear. These results show that the high glucose concentration in diabetes can impair the action of ascorbic acid at the cellular level. This may further accentuate the problem of decreased availability of this vitamin as a result of its low plasma concentration.

Amino Acids↗
PubMed1991

Use of X-ray diffraction in study of human diabetic and aging collagen.

Extensive investigations of the solubility and fluorescence of collagen fibers in diabetes have revealed that there are significant changes in their physical properties. These changes are associated with increased cross-link formation. We used X-ray diffraction to study these changes in human extensor tendons at a molecular level in relation to both aging and diabetes. Our results indicate that diabetes induces significant alterations in the ultrastructure of collagen in the lateral packing of the molecules and the axial structure of the specimen. These changes can be induced in normal tendon by incubation in ribose and glucose-6-phosphate but are different from those associated with the normal process of aging.

Adolescent↗
PubMed1990

The effects of dietary n - 3 fatty acid in animal models of type 1 and type 2 diabetes.

We studied the incorporation of dietary n - 3 fatty acids from marine oils into red cell membranes, using animal models of type 1 diabetes (streptozotocin-treated Wistar rats) and type 2 diabetes (gold-thioglucose-injected CBA/T6 mice). In type 1 diabetic rats, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were higher following marine oil supplementation, and the increase in EPA was significantly greater than in non-diabetic animals (3.4 +/- 1.4% vs. 0.8 +/- 1.6%). Marine oil supplementation also resulted in higher levels of EPA and DHA in mice, but the increases were quantitatively similar with and without type 2 diabetes. Improvement in glycosylated haemoglobin following n - 3 fatty acid feeding was only found in type 2 diabetes (6.5 +/- 2.9% vs. 9.5 +/- 1.2%). This was associated with a higher plasma insulin concentration (170 +/- 40 vs. 136 +/- 41 mU/ml). The theory that n - 3 fatty acids improve insulin sensitivity would have predicted a decrease in plasma insulin levels. Our results suggest that n - 3 fatty acids may modify insulin secretion.

Animals↗
PubMed1990

Abnormalities of ascorbic acid metabolism and diabetic control: differences between diabetic patients and diabetic rats.

Ascorbic acid is required in the synthesis of collagen and is also an important anti-oxidant. In a previous study, plasma ascorbic acid concentration was found to be decreased in diabetic patients but there was no relationship with blood glucose level. In the current study of diabetic patients, both plasma ascorbic acid and its urinary excretion correlated inversely with glycosylated hemoglobin level. Plasma ascorbic acid was also lower in diabetic rats but urinary ascorbic acid was elevated. The divergent trend in urinary ascorbic acid excretion observed in diabetic patients and diabetic rats may be due to difference in the ability of these two species to synthesize ascorbic acid. Difference in renal reabsorption of ascorbic acid may also be a relevant factor. The lower plasma and urinary ascorbic acid levels in diabetic patients with more severe hyperglycaemia indicates that this group of patients is particularly at risk of developing deficiency of this vitamin. As ascorbic acid has many important functions in the body, it may be necessary to supplement this vitamin in patients with chronically poorly controlled diabetes.

Adult↗
PubMed1989

Increase in crosslinking of nonenzymatically glycosylated collagen induced by products of lipid peroxidation.

The increase in crosslinking in normal and nonenzymatically glycosylated rat tail tendon collagen after treatment with decomposing lipid hydroperoxides was assessed by measuring the breaking time of tendons immersed in 7 M urea under a 3 g weight at 40 degrees C (thermal rupture time). The incubation of tendons in 200 mM glucose for 43 h at 40 degrees C increased thermal rupture times from 5.15 to 26.38 min, (P less than 0.001) with no significant corresponding increase in tendons incubated in buffer alone. After incubation of the glycosylated tendons in the presence of peroxidized linoleic/arachidonic acid vesicles for about 20 h, their thermal rupture time increased to 3360 min (P less than 0.001). The rupture time for normal tendons after the same treatment was 206 min. These apparent crosslinking increases cannot be fully accounted for by reactions involving malondialdehyde, as incubation of both glycosylated and normal tendons in enzymatically produced malondialdehyde resulted in a modest two- to threefold increase in thermal rupture time.

Animals↗
PubMed1989

The effect of improved control on blood filtration properties and non-enzymatic glycosylation of erythrocyte proteins in type 2 diabetes.

Abnormal blood flow in the microcirculation has been reported in diabetes and may be important in the pathogenesis of diabetic complications. The mechanism of this is not understood but non-enzymatic glycosylation of erythrocyte membrane or haemoglobin causing reduced erythrocyte deformability and a secondary change in filtration properties of blood have been suggested as possible factors. The relationship of non-enzymatic glycosylation of erythrocyte membrane and glycosylated haemoglobin to filtration time of blood was investigated during stabilization of diabetes with sulphonylurea therapy. Over an 8-month period, glycosylated haemoglobin, non-enzymatic glycosylation of erythrocyte membrane, and filtration time fell by 41%, 71%, and 53% of the initial value, respectively, but the rate of decline was slower for filtration time which did not change significantly until the last month. Due to the different time-course of improvement, no relationship was found between filtration time and glycosylated haemoglobin or non-enzymatic glycosylation of erythrocyte membrane whereas glycosylated haemoglobin and non-enzymatic glycosylation of erythrocyte membrane correlated significantly (r = 0.49, p less than 0.001). These results suggest that the abnormal filtration property of blood in diabetes is not a direct consequence of non-enzymatic glycosylation, and suggest that the erythrocytes made in the hyperglycaemic milieu are abnormally rigid. The filtration properties of blood are only improved when new generations of erythrocytes enter the circulation.

Diabetes Mellitus, Type 2↗
PubMed1989

Anti-smoking programme for diabetic patients: the agony and the ecstasy.

It is generally accepted that people with diabetes should be encouraged to abstain from smoking but there are few data on the best strategy to implement this. In a preliminary survey of our diabetic patients, knowledge of the general and specific health effects of smoking was poor. In a prospective study of 70 diabetic smokers, only 50% agreed to participate in an anti-smoking programme, and the drop-out rate was high irrespective of whether the content of the programme was general or specific for diabetes. The enrollment rate was best 2 months after the diagnosis of diabetes and the drop-out rate was highest in patients recruited immediately following diagnosis. According to self-reported data, cigarette consumption fell after the first session of the anti-smoking programme but this could not be verified by the measurement of plasma cotinine. It is concluded that an anti-smoking counselling programme based on provision of information, within the context of a specialized diabetes centre, is not cost-effective.

Cotinine↗
PubMed1989

Ascorbic acid metabolism and polyol pathway in diabetes.

It has been reported previously that the plasma concentration of ascorbic acid (AA) is reduced in streptozocin-induced diabetic rats and can be normalized by treatment with the aldose reductase inhibitor tolrestat. This study was designed to investigate further the relationship between the polyol pathway and AA metabolism in diabetic rats. Disturbance of AA metabolism was demonstrable after 1 wk of diabetes. Dietary myo-inositol supplementation was effective in normalizing plasma AA levels, as was treatment with tolrestat. In untreated diabetes, despite low plasma AA concentration, there was increased urinary excretion of AA that was reversed by treatment with either tolrestat or myo-inositol. In contrast, AA supplementation normalized plasma AA concentrations while further increasing urinary AA excretion. The abnormality of AA metabolism was less severe in galactose-fed rats, which had normal plasma AA levels and only minor increases in urinary AA excretion. These studies demonstrated a disturbance in the regulation of plasma and urinary AA concentration in experimental diabetes and confirmed the relationship of AA with the polyol pathway. Because AA has many important biological functions, abnormalities of AA metabolism could be important in the pathogenesis of some diabetic complications. The interaction of the polyol and AA pathways suggests that this could be another site of action for aldose reductase inhibitors.

Aldehyde Reductase↗
PubMed1989

Effects of combined insulin-sulfonylurea therapy in type II patients.

We conducted a double-blind crossover study to determine which patient characteristics best predict a beneficial response to combined insulin-glyburide therapy. Glyburide (15 mg/day) or placebo was added to the treatment regimen of 31 insulin-treated type II (non-insulin-dependent) diabetic subjects. During glyburide therapy, there was a significant improvement in glycemic control with a reduction in glycosylated hemoglobin from 9.9 +/- 1.3 to 9.1 +/- 1.3% (P less than .001). Patients who responded had higher fasting C-peptide levels (P less than .001) and shorter durations of insulin therapy (P less than .01) than those who did not respond. Glyburide withdrawal was associated with a greater than expected deterioration in glycemic control. Patients on insulin therapy for greater than 8 yr are unlikely to benefit significantly from the addition of glyburide to their treatment regimen.

Aged↗
PubMed1988

Catalysis of lipid peroxidation by glucose and glycosylated collagen.

Peroxidation of membranes of linoleic/arachadonic acid vesicles at 40 degrees C was catalysed by glucose or glycosylated collagen. Kinetics of hydroperoxide production were similar in both cases. There was a kinetic lag, the duration of which was inversely proportional to the amount of glucose or glycosylated collagen used to initiate the peroxidation. This was followed by a rapid increase in the rate of oxidation. The final rate was independent of the amount of catalyst added. Vesicle lysis accompanied the increases in peroxidation. Addition of desferrioxamine, an iron chelator, only partially inhibited the oxidative process.

Animals↗