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Biomedical subjects

G Jerums

Publications and source records attributed to G Jerums.

At least 73 records · Page 4Linked to original sources

Diabetes and hypertension: prognostic and therapeutic considerations.

Hypertension and diabetes are common disorders which frequently co-exist. Both are risk factors for atherosclerotic vascular disease and their combination is associated with an increased incidence of nephropathy, ischaemic heart disease, peripheral vascular disease, and stroke. Several trials such as the HDFP and SHEP studies that included diabetic patients have demonstrated the beneficial effects of antihypertensive therapy in reducing mortality. In diabetes, studies have focussed predominantly on the efficacy of antihypertensive therapy in reducing the progression of diabetic kidney disease. Such therapy has been shown to decrease albuminuria in the setting of "normal" and elevated blood pressure in both type I and type II diabetic patients. This reduction in albuminuria has been observed in microalbuminuric diabetic patients and also in those with overt renal disease. Recent studies in type I diabetic patients with overt nephropathy indicate that these effects on urinary albumin excretion are associated with reduction in the rate of decline in renal function and development of end-stage renal failure. Indeed, several groups have shown that the initiation of antihypertensive therapy improves the prognosis of type I diabetic patients with nephropathy. While certain classes of drugs may reduce the rate of progression of complications such as nephropathy, others have side effect profiles that are disadvantageous in patients with diabetes.

Angiotensin-Converting Enzyme Inhibitors↗

Microalbuminuria in diabetes.

This statement summarises current understanding of the role of microalbuminuria in diabetic nephropathy and describes its natural history and clinical relevance. It outlines core facts and makes recommendations for the management of patients with persistent microalbuminuria.

Albuminuria↗

Complementary effects of pravastatin and nicotinic acid in the treatment of combined hyperlipidaemia in diabetic and non-diabetic patients.

BACKGROUND: Given that treatment with a single drug is frequently unsuccessful in patients with combined hyperlipidaemia, there is a rationale for the study of regimens using drugs that have complementary therapeutic profiles. We therefore set out to compare the efficacy of a combined pravastatin and nicotinic acid regimen with higher dose monotherapy using either drug in patients with non-insulin-dependent diabetes and in non-diabetic patients with combined hyperlipidaemia. METHODS: Forty-four patients with total-cholesterol levels of 6.5 mmol/l or higher and triglyceride levels of 2.5 mmol/l or above were randomly assigned to receive either pravastatin alone (40mg/day) or nicotinic acid alone (1500mg/day) for 12 weeks. At the end of this period, the participants received a combination of pravastatin (20mg/day) and nicotinic acid (1000mg/day) for a further 12 weeks. The lipid parameters measured included levels of total cholesterol, triglycerides, low-density-lipoprotein (LDL) cholesterol and high-density-lipoprotein (HDL) cholesterol. RESULTS: Thirty-three patients (22 without and 11 with diabetes) completed the protocol. Monotherapy with pravastatin was more effective than that with nicotinic acid in reducing levels of total cholesterol (-24.9 versus -9.8%, P<0.001) and LDL cholesterol (-32.1 versus -16.9%, P < 0.01), similar in reducing levels of triglyceride (-28.0 versus -31.8%, NS) and tended to be less effective in elevating levels of HDL cholesterol (+16.4 versus +30.8%, P = 0.06). Combination therapy was more effective than pravastatin monotherapy in reducing levels of triglyceride (-39.3 versus -28.0%, P < 0.05) and elevating those of HDL cholesterol (+35.6 versus +16.4%, P < 0.001) and was equally effective in reducing total-cholesterol (-22.3 versus -24.9%, NS) and LDL-cholesterol (-27.1 versus -32.1%, NS) levels. Combination therapy was more effective than nicotinic acid monotherapy in reducing levels of total cholesterol (-23.8 versus -9.8%, P < 0.001), triglyceride (-39.4 versus -31.8%, P < 0.05) and LDL cholesterol (-35.7 versus -16.9%, P < 0.05) and equally effective in elevating HDL-cholesterol levels (+33.6 versus +30.8%, NS). Diabetic and non-diabetic participants responded similarly to combination therapy. Eleven patients (25%) were withdrawn from the study: nine as a result of nicotinic acid intolerance (flushing and nausea) and one through pravastatin intolerance (nausea); one patient died of a myocardial infarction. Combination therapy elevated glycosylated haemoglobin A1c levels in non-diabetic patients (5.5 to 5.8%, P < 0.001); in diabetic patients, however, the observed rise (7.4 to 7.9%) was not statistically significant. Fasting plasma glucose levels, liver function tests and levels of creatine kinase or uric acid were unaffected by either monotherapy or by combination therapy, with the exception of an elevation of the glucose level in diabetic patients receiving nicotinic acid monotherapy. CONCLUSION: Pravastatin and nicotinic acid in lower-dose combination are more effective than pravastatin alone in reducing levels of triglyceride and elevating those of HDL cholesterol and are more effective than nicotinic acid alone in reducing total-cholesterol triglyceride and LDL-cholesterol levels. Combination therapy is equally effective in type-II diabetic and non-diabetic people. The complementary effects of the combination therapy on lipid levels suggest that this regimen should be considered as a therapeutic option in patients with combined hyperlipidaemia who tolerate the side effects of nicotinic acid.

Adult↗

Progressive decline in renal function in diabetic patients with and without albuminuria.

This study describes patterns of progression of albuminuria and renal function in a subgroup of 40 patients from a total cohort of 211 diabetic patients (118 type I, 93 type II) followed over a period of 8-14 years. Forty patients (18 with type I diabetes, 22 with type II diabetes) showed progressive increases in albumin excretion rate (AER) and/or decreases in creatinine clearance (CC) during the study period. Of these, AER alone increased in 15 patients, AER increased and CC decreased in 13 patients, and CC alone decreased in 12 patients, with a similar distribution of type I and type II diabetic patients in each group. Of the 28 patients who showed an increase in albuminuria, AER increased at an annual rate of 30-40%, resulting in a 4- to 8-fold increase in AER to > 20 micrograms/min during the study. Of the 25 patients who showed a decrease in renal function, CC decreased at an annual rate of 4-5 ml/min, resulting in an approximate halving of CC to < 90 ml/min during the study. The rate of fall in CC was not related to the presence or absence of concomitant increases in albuminuria. However, a significant preponderance of women in the group showed a decline in CC alone. The decline in CC was associated with an increase in plasma creatinine as well as a progressive decrease in urinary creatinine excretion, but the underlying mechanisms remain unexplained. These data support the concept that a subgroup of diabetic patients may show a decline in renal function in the absence of significant increases in AER.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Day-night blood pressure variation in normotensive, normoalbuminuric type I diabetic subjects. Dippers and non-dippers.

OBJECTIVE: To examine day-night blood pressure (BP) variation in normotensive, normoalbuminuric subjects with type I diabetes and to assess the prevalence of an impaired nocturnal BP fall. RESEARCH DESIGN AND METHODS: Fourteen healthy volunteers and 13 normotensive, normoalbuminuric subjects with type I diabetes were studied with an ambulatory sphygmomanometric device for 24 h. RESULTS: No significant difference was found between diabetic and control groups with regard to daytime systolic blood pressure (sBP) or diastolic blood pressure (dBP). However, the mean nighttime sBPs (P < 0.01) and dBPs (P = 0.01) were significantly higher in the diabetic group compared with the control group. Furthermore, the night/day ratio for both sBP (P < 0.01) and dBP (P < 0.01) was significantly higher in the diabetic group. Approximately half of the diabetic subjects studied were non-dippers when defined either by a nocturnal fall in sBP/dBP of < 10/5 mmHg (5/13 vs. 0/14, P < 0.05: diabetic group vs. control group) or a day to night fall in either sBP (7/13 vs. 2/14, P < 0.05) or dBP (6/13 vs. 0/14, P < 0.01) of < 10%. CONCLUSIONS: Ambulatory BP may reveal impaired nocturnal BP fall in normotensive, normoalbuminuric subjects with type I diabetes. These subjects may be at greater risk of certain complications as a consequence of an increased BP burden.

Adult↗

Disparate effects of castration on renal structure and function in the streptozotocin diabetic rat.

Diabetic children are protected from the complications of diabetes until puberty, suggesting the involvement of a hormonal mechanism. In order to investigate the contribution of sex steroids to the development of diabetic nephropathy, castrated Wistar-Kyoto rats were made diabetic with streptozotocin and compared with intact diabetic rats. In intact rats, 32 weeks of diabetes resulted in hyperfiltration (p = 0.0001) and a marked increase in albuminuria (control, 1.3 x/divided by 1.3 vs diabetes intact, 11.8 x/divided by 1.3 mg/day, p < 0.001). Concomitant structural changes included glomerular basement membrane thickening (diabetes, 199.2 +/- 7.9 vs control, 175.9 +/- 3.9 nm, p = 0.02) and increased mesangial volume (diabetes, 194 +/- 14 vs control, 129 +/- 20 microns 3, p = 0.02). Although castration resulted in blood pressure lowering of 12 mmHg (p = 0.0003), albuminuria increased to the same extent in intact and castrated diabetic rats (castrated diabetic 10.5 x/divided by 1.3 mg/day). Glomerular filtration rate was lower in castrated rats than in intact rats prior to induction of diabetes, but increased similarly with induction of diabetes. Castrated diabetic rats had increased mesangial volume (castrated diabetic, 213 +/- 20 microns 3), but glomerular basement membrane thickness was lower than in intact diabetic rats (castrated diabetic, 179.5 +/- 4.5 nm). Thus, there is a dissociation between basement membrane thickening and albuminuria in this model of diabetic kidney disease. The mechanism of action of castration on glomerular function and structure remains to be elucidated but may relate to indirect effects such as reduction of blood pressure or renal polyol accumulation or a direct effect of sex steroids.

Albuminuria↗

Relationship of progressively increasing albuminuria to apoprotein(a) and blood pressure in type 2 (non-insulin-dependent) and type 1 (insulin-dependent) diabetic patients.

This study has explored the temporal relationship between apoprotein(a), blood pressure and albuminuria over a mean interval of 11 years in a cohort of 107 diabetic patients of whom 26 (14 Type 2 (non-insulin-dependent), 12 Type 1 (insulin-dependent) had progressively increasing albuminuria ('progressors'). In Type 2 diabetic patients, no significant differences were noted for HbA1, blood pressure, creatinine clearance or serum lipids between progressors and non-progressors. In Type 1 diabetic patients, final systolic and diastolic blood pressures were higher in progressors compared with non-progressors and progressors showed impairment of renal function in association with a rise in blood pressure at the macroalbuminuric stage. Initial apoprotein(a) levels were similar in progressors and non-progressors of either diabetes type. Apoprotein(a) levels increased exponentially with time in 12 of 14 Type 2 progressors but only in 5 of 12 Type 1 progressors (p < 0.01). In Type 2 diabetic patients, the annual increase in apoprotein(a) levels was 9.1 +/- 2.4%, which was significantly greater than in non-progressors, 2.0 +/- 1.2% (p < 0.01) and also exceeded the rates of increase of apoprotein(a) in progressors with Type 1 diabetes, 4.0 +/- 1.4%, (p < 0.05). Apoprotein(a) levels correlated significantly with albuminuria in 8 of 14 Type 2 progressors but only in 3 of 12 Type 1 progressors (p < 0.05). The rate of increase of apoprotein(a) levels was not related to mean HbA1, creatinine or creatinine clearance levels, or to albuminuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Dissociation of blood pressure and albuminuria in normal subjects infused with angiotensin II and noradrenaline.

1. Albuminuria is a predictor of diabetic renal disease and atherosclerosis. Changes in blood pressure (BP) may influence albuminuria. 2. The effect of acute BP elevation on albumin excretion rates (AER) using noradrenaline (NA) and angiotensin II (AII) infusions in six normal subjects was examined. 3. The average rise in BP during a 120 min infusion was 23 mmHg for AII and 16 mmHg for NA. 4. There was a marked dissociation between AER and BP levels in both AII and NA infusions. 5. Previously described correlations between BP and AER in ambulatory BP studies may be explained by other factors such as exercise and postural changes.

Adolescent↗

The effects of perindopril and triple therapy in a normotensive model of diabetic nephropathy.

The effect of the angiotensin-converting enzyme inhibitor, perindopril, on functional and structural parameters of diabetic nephropathy has been compared with triple therapy (hydralazine, reserpine, and hydrochlorothiazide) in normotensive, STZ-induced diabetic Sprague-Dawley rats. Animal groups included control rats, diabetic rats treated with perindopril, diabetic rats receiving triple therapy, and untreated diabetic rats. Treatment was continued for 32 wk. Blood pressure reduction and severity of diabetes, as assessed by body weight and glycemic control were similar with both drug regimens. A similar rise in plasma renin activity occurred in the two groups receiving antihypertensive drugs, whereas the perindopril but not the triple therapy group had suppressed plasma angiotensin-converting enzyme activity. No significant difference was observed in renal function among the four groups. Diabetes was associated with a progressive increase in albuminuria, but this rise was ameliorated by both perindopril and triple therapy. No significant difference was noted in albuminuria between triple therapy and perindopril-treated diabetic rats. Diabetes was associated with glomerular basement membrane thickening, mesangial expansion, and glomerular volume. No glomerular ultrastructural parameter was affected by antihypertensive drugs. No specific benefit of angiotensin-converting enzyme inhibition over triple therapy could be detected in this normotensive model of diabetic nephropathy.

Analysis of Variance↗

The effects of dietary cholesterol on experimental diabetic nephropathy.

Hyperlipidaemia has been previously shown to accelerate various models of renal disease. The present study has evaluated the effects of dietary cholesterol supplementation on functional and structural aspects of experimental diabetic nephropathy. Control and streptozotocin diabetic male Sprague Dawley rats were randomized to receive a normal diet or a high cholesterol (4% cholesterol + 1% cholic acid) diet. After 32 weeks, serum lipids, glycaemic control, urinary albumin excretion and glomerular ultrastructural parameters were evaluated in the 4 groups. Diabetes was associated with increased total cholesterol and triglyceride levels. Cholesterol supplementation increased total and decreased HDL-cholesterol in control and diabetic rats. Diabetes increased albuminuria but cholesterol supplementation did not influence urinary albumin excretion. In diabetic rats, glomerular basement membrane thickness and glomerular volume were increased but cholesterol supplementation did not influence any glomerular ultrastructural parameter. In control rats, increased dietary cholesterol intake led to an increase in blood pressure and glomerular volume. In contrast to other models of renal disease, experimental diabetic nephropathy does not appear to be exacerbated by dietary cholesterol supplementation.

Albuminuria↗

Antihypertensive therapy in a model combining spontaneous hypertension with diabetes.

We have compared the effects of the angiotensin converting enzyme inhibitor, perindopril, and a conventional antihypertensive regimen (triple therapy: hydralazine, reserpine and hydrochlorothiazide) on kidney function and albuminuria in hypertensive diabetic rats. Diabetes was induced with streptozotocin in spontaneously hypertensive (SHR) rats and they were randomized to receive no treatment, perindopril or triple therapy. Antihypertensive drugs were commenced at the time of induction of diabetes and continued for 16 weeks. Blood pressure reduction was equal in the groups treated with perindopril or triple therapy. All groups had similar severity of diabetes as determined by body weight, serum glucose and glycated hemoglobin levels. Whereas plasma renin activity rose in both the perindopril and triple therapy groups, it is likely that the effects on angiotensin II levels were opposite since perindopril but not triple therapy was associated with a significant reduction in plasma angiotensin converting enzyme activity. Diabetes was associated with an increase in glomerular filtration rate. At 12 weeks, glomerular filtration rate was higher in the perindopril treated group when compared to the triple therapy group, but neither group treated with antihypertensive therapy was different to untreated diabetic rats. Both drug regimens reduced albuminuria in the diabetic rats to a similar degree apparently independently of their effects on the renin-angiotensin system. Studies in diabetic subjects are warranted to evaluate different classes of antihypertensive drugs with respect to their effects on kidney function, proteinuria and glomerular morphology.

Albuminuria↗

Angiotensin converting enzyme inhibition and calcium channel blockade in incipient diabetic nephropathy. The Melbourne Diabetic Nephropathy Study Group.

Small increases in blood pressure are a feature of incipient diabetic nephropathy, and mean blood pressure often correlates with the degree of albuminuria in such patients. Antihypertensive therapy with angiotensin converting enzyme inhibitors (CEI) or calcium channel blockers (CCB) has been assessed in several studies to determine if either form of treatment modifies incipient diabetic nephropathy and its evolution to established nephropathy. The acute renal hemodynamic effects of CEI differ from those of CCB under certain circumstances. In incipient diabetic nephropathy, therapy with CEI but not CCB tends to reduce filtration fraction, especially in hyperfiltering patients. In hypertensive patients with incipient diabetic nephropathy, both treatments result in a decrease in albuminuria and the responses are mainly dependent on the lowering of systemic blood pressure. In normotensive patients with incipient diabetic nephropathy, a lowering of mean blood pressure with CEI or CCB is not found consistently while effects on albuminuria are difficult to interpret. Short- and long-term therapy with CEI lowers or stabilizes albuminuria. Short-term administration of CCB has at times been associated with increases in albuminuria, but a comparison of CEI and CCB over 12 months in the Melbourne Diabetic Nephropathy Study (MDNS) has shown that both drugs stabilize albuminuria with no significant differences in their effects. Serial analysis of urinary sodium excretion in the MDNS shows that the hypotensive response to CEI in incipient nephropathy is highly dependent on sodium intake, and that sodium intake may modulate albuminuria during both CEI and CCB therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗

Semi-quantitative determination of microalbuminuria by urinary dipstick.

Microalbuminuria predicts subsequent clinical nephropathy and mortality in diabetic patients. This study was undertaken to determine the usefulness of a new immunochemical urinary dipstick test (Micral-Test, Boehringer Mannheim, GmbH Mannheim, Germany) in identifying urinary albumin concentrations within the microalbuminuric range (urinary albumin concentration 20-200 mg/L). Twenty-four hour urine specimens were collected from 298 consecutive diabetic outpatients. Micral-Test was performed by two laboratory scientists blinded to each other's results and those of radioimmunoassay (RIA) and immunoturbidimetry on the same specimen. When compared with RIA, Micral-Test had an overall sensitivity of 92.2%, specificity of 92.3% and positive predictive value of 86.4%. However, at the threshold value of 20 mg/1 Micral-Test showed false positive results in 37.8% of samples when compared with RIA. Similar results were obtained when Micral-Test was compared with immunoturbidimetry. We conclude that Micral-Test is a useful screening method for the detection of microalbuminuria. We suggest that positive tests be confirmed by a timed urine collection using established methodology and that patients whose Micral-Test is negative be subjected to annual retesting.

Albuminuria↗

Circulating PTH and PTHrP levels before and after treatment of tumor induced hypercalcemia with Pamidronate Disodium (APD).

The effect of lowering ionized calcium on circulating parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) was assessed in twenty patients with hypercalcemia of malignancy following treatment with Pamidronate Disodium. Ionized calcium levels fell rapidly in all treated patients. PTH concentrations were initially suppressed below normal in 18 patients, but rose from 0.48 +/- 0.42 pmol/L to 3.63 +/- 3.13 pmol/L (p less than 0.01) after treatment, reaching higher than normal values in some patients even in the presence of persistent hypercalcemia. PTHrP concentrations did not change significantly after treatment. These findings are consistent with an increased sensitivity of parathyroid tissue to changes in ionized calcium following prolonged exposure to hypercalcemia. Regulation of tumor secretion of PTHrP by calcium was not apparent within the range of calcium concentrations in this study.

Calcium↗

Focal induction of IGF binding proteins in proximal tubules of diabetic rat kidney.

Diabetes-associated kidney enlargement is associated with increased kidney insulinlike growth factor I (IGF-I) binding. IGF-I binds to the type I IGF receptor, which mediates most of its actions, and to specific binding proteins (IGFBPs), which modulate its actions. To explore the nature and extent of IGF-I binding in the kidney, in vitro autoradiography was used to map the distribution of IGF binding in control and diabetic rat kidney. Specificity studies were performed with increasing concentrations of unlabeled IGF-I, IGF-II, des(1-3)IGF-I (an IGF-I derivative that binds to receptors normally but with decreased affinity to binding proteins), and insulin. In control rats, diffuse binding was found throughout the kidney with increased density in the papilla. Binding specificity in the cortex and outer medulla was typical of the type I IGF receptor (IGF-I = des[1-3]IGF-I greater than IGF-II much greater than insulin). Binding in the outer medulla of diabetic kidney was typical of the type I IGF receptor. A marked focal increase in proximal tubular binding occurred in 13 of 22 postpubertal diabetic rats. Binding specificity of the proximal tubular binding was consistent with the predominance of an IGF binding protein (IGF-I = IGF-II greater than des[1-3]IGF-I with minimal displacement by insulin). Northern-blot analysis revealed increased IGFBP-1 and IGFBP-3 mRNA in cortical tissue from diabetic rats displaying increased proximal tubular binding but not from diabetic rats not displaying this phenomenon. As cell surface association of IGFBPs is linked to potentiation of IGF activity, a possible mechanism for potentiation of local IGF-I action may be provided.

Animals↗