Showing papers by "Mark E. Cooper published in 1993"
TL;DR: In predisposed diabetic patients, long-term glycemic control is correlated with the rate of development of early renal abnormalities and Repeated measurements of AER from the time of diagnosis may be useful in the early detection of patients who will develop microalbuminuria and ultimately overt diabetic nephropathy.
99 citations
TL;DR: Variation in maximum osmotic adjustment and desiccation tolerance were determined before anthesis for 21 lines of Sorghum bicolor (L.) Moench, selected on the basis of their capacity for osmosis adjustment and for their putative drought resistance, to suggest that the screening procedure developed in this study in robust, and that it could be used to evaluate the inheritance of osmotics in breeding populations.
38 citations
TL;DR: The effect of the angiotensin-converting enzyme inhibitor, perindopril, on functional and structural parameters of diabetic nephropathy has been compared with triple therapy in normotensive, STZ-induced diabetic Sprague-Dawley rats.
Abstract: 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.
38 citations
TL;DR: It is suggested that increases in apoprotein(a) levels commence during the microalbuminuria stage in diabetic patients, which is earlier than has been documented in non-diabetic proteinuria.
Abstract: 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. The rate of rise of apoprotein(a) was not influenced by initial apoprotein(a) levels, suggesting that specific apoprotein(a) isoforms do not influence albuminuria-related increases in apoprotein(a). The data are consistent with the hypothesis that apoprotein(a) levels increase in response to albuminuria and may be part of a self-perpetuating process. This study also suggests that increases in apoprotein(a) levels commence during the microalbuminuria stage in diabetic patients, which is earlier than has been documented in non-diabetic proteinuria.
37 citations
TL;DR: In this article, a more coordinated and efficient procedure for identifying useful lines for Australian breeding programs was evaluated by assessing the potential for exploiting correlated response to selection for grain yield between CIMMYT international and Australian evaluation trials.
34 citations
TL;DR: Indirect selection and pattern analysis were used to examine the magnitude and form of genotype x environment (GE) interactions for sugar yield in sugarcane clones in southern Queensland and suggest that more emphasis should be placed on sampling a greater number of locations than on the testing of clonal ratooning ability within locations to improve the chances of obtaining both broadly and specifically adapted sugarCane varieties.
Abstract: To develop a strategy to improve the efficiency of selection, indirect selection and pattern analysis were used to examine the magnitude and form of genotype x environment (GE) interactions for sugar yield in sugarcane clones in southern Queensland. Clone x location interactions were the predominant source of clone X environment interactions and were much larger than clone x crop-year and clone x location x crop-year interactions. Both the indirect selection study and the pattern analysis emphasised the relative magnitude of these sources of interactions. Pattern analysis strongly associated crop classes at each location, and indirect selection analysis emphasised an opportunity to exploit correlated genetic advance between crop classes within a location. These suggest that more emphasis should be placed on sampling a greater number of locations than on the testing of clonal ratooning ability within locations. This would improve the chances of obtaining both broadly and specifically adapted sugarcane varieties.
28 citations
TL;DR: The theory for indirect selection is related to classification methodology for grouping of environments in plant breeding experiments and subsets of international environments which improved indirect response to selection in five of the six Australian environments are discussed.
22 citations
Journal Article•
16 citations
TL;DR: Environmental classifications based on the standardised and rank transformations were generally superior to those based onThe untransformed and coded transformations, and the magnitude of this advantage differed between the Australian environments but was substantial for the two environments which expressed the greatest opportunity for exploiting indirect selection.
13 citations
TL;DR: It is suggested that frequent intermittent microalbuminuria predicts the future development of persistent micro Albuminuria particularly in IDDM patients and that AER should be assessed by serial rather than single measurements.
Abstract: Persistent microalbuminuria [albumin excretion rate (AER): 30-300 micrograms/min] is predictive of clinical nephropathy in patients with insulin-dependent diabetes mellitus (IDDM) and cardiovascular mortality in addition to nephropathy in patients with non-insulin-dependent diabetes. The clinical significance of intermittent microalbuminuria, however, is unknown. We performed serial measurements of urinary albumin excretion at intervals of approximately 6 months in 139 diabetic patients who at entry did not have persistent microalbuminuria to determine whether intermittent microalbuminuria occurs more frequently in those patients who subsequently develop persistent microalbuminuria. The relative risk for the development of persistent microalbuminuria in diabetic patients with a greater proportion than 3 out of 20 determinations in the microalbuminuric range was 17.4 (95% confidence interval, 3.92-77.2) in those with IDDM and 2.78 (0.99-7.8) in those with non-insulin-dependent diabetes when compared with matched diabetic patients with fewer elevated measurements. These data suggest that frequent intermittent microalbuminuria predicts the future development of persistent microalbuminuria particularly in IDDM patients and that AER should be assessed by serial rather than single measurements.
9 citations
TL;DR: In this paper, the variability in patterns of performance that could be expected through experimental error at each environment was assessed using repeats of a check line (cultivar) and the hierarchical classification was truncated when the repeats of the check line were partitioned into different groups.
Journal Article•
TL;DR: In contrast to other models of renal disease, experimental diabetic nephropathy does not appear to be exacerbated by dietary cholesterol supplementation.
Abstract: 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.