Pharmacokinetics following continuous subcutaneous insulin infusion of insulin aspart with or without initial subcutaneous bolus.

AIM: To evaluate time to steady state insulin concentration (C(ss)) following continuous subcutaneous insulin infusion (CSII) of insulin aspart (IAsp) with or without an initial s.c. bolus. METHODS: In random order 10 healthy volunteers were given a basal insulin infusion rate (0.5 U/h) for 8 h with or without an initial s.c. bolus (1.4 U). Serum IAsp was measured until 3 h after infusion was stopped. RESULTS: An overshoot of IAsp was seen before C(ss) was achieved following an initial bolus of insulin as compared to no bolus. The apparent half-life (t((1/2))) with or without bolus did not differ (p = 0.15). Time to steady state (T(ss)) was evaluated in two ways: (1) T(ss) defined as the first point within an interval of C(ss)+/- 2 x CV was 233 vs. 166 min with and without a bolus respectively (p = 0.068). (2) A t-test was performed for each concentration-time point vs. mean C(ss), and the first point with no significance was defined, T(ss). This gave 208 (p = 0.09) and 178 min (p = 0.24) with and without bolus respectively. Mathematical modelling suggests that an ideal mean bolus should be 0.89 U, and that this bolus dose may result in a shorter T(ss). CONCLUSION: A bolus of 1.4 U resulted in an overshoot of serum IAsp before C(ss) and a longer period before C(ss) is achieved. Mathematical modelling suggests that a mean bolus of 0.89 U would result in a faster achievement of C(ss) compared to no bolus.

Left ventricular hypertrophy in normoalbuminuric type 2 diabetic patients not taking antihypertensive treatment.

BACKGROUND: Left ventricular hypertrophy (LVH) is an independent risk factor for myocardial ischaemia, cardiac arrhythmia, sudden death, and heart failure, all common findings in patients with type 2 diabetes. AIM: To determine the prevalence of, and risk factors for, LVH in normoalbuminuric type 2 diabetic patients not taking antihypertensive treatment. DESIGN: Cross-sectional study. METHODS: From 1994 to 1998, M-mode echocardiography was performed by one experienced examiner in 262 consecutive, normoalbuminuric Caucasian type 2 diabetic patients, all with blood pressure <160/95 mmHg and not taking antihypertensive medication. Mean +/- SD age was 54 +/- 10 years, 109 were women, and median known duration of diabetes was 4 (range 1-28) years. Body mass index (BMI) was 28 +/- 5 kg/m(2), and blood pressure 134 +/- 13/79 +/- 8 mmHg, all means +/- SD. Median urinary albumin excretion rate was 9 (range 2-30) mg/24 h. RESULTS: The prevalence of LVH indexed to height(2.7) was 43% (95%CI 38-50%), and was similar in men and women. BMI, HbA(1c) and log urinary albumin excretion were significantly associated with left ventricular hypertrophy in a logistic regression model, whereas sex, age, known duration of diabetes and blood pressure were not. Similar results were obtained for left ventricular mass index. DISCUSSION: LVH was frequent in our normoalbuminuric type 2 diabetic patients not taking antihypertensive treatment. Several potentially modifiable risk factors, such as raised BMI, poor glycaemic control and elevated urinary albumin excretion rate, were associated with LVH.

Preventing diabetic nephropathy: an audit.

In type 1 diabetic patients with microalbuminuria not receiving antihypertensive treatment, an increase in urinary albumin excretion rate (AER) of 6% to 14%/year and a risk for the development of diabetic nephropathy of 3% to 30%/year have previously been reported. The aim of the present study was to audit the effect of angiotensin converting enzyme (ACE) inhibition on the progression of microalbuminuria and development of diabetic nephropathy. We consecutively identified 227 type 1 diabetic patients with persistent microalbuminuria (urinary AER between 30 and 300mg/24h, ELISA). According to the level (> or = 100 or < 100mg/24 h) and/or rate of progression in urinary AER (>6% or < or =6%/year), patients were divided into a high-risk group (n= 177) and a low-risk group (n= 50) for development of diabetic nephropathy. According to international guidelines, all patients at high-risk were recommended ACE-inhibitor treatment. Throughout the study, 67% of the patients were treated with an ACE inhibitor. Urinary AER significantly declined by 8.3%/year (95% CI: 2.8 to 13.9) in the whole group of patients, and the risk for the development of diabetic nephropathy during follow-up was 3.5%/year. Glycaemic control and blood pressure remained unchanged during the study. The implementation of modified international guidelines regarding the use of ACE inhibition in the treatment of microalbuminuric type 1 diabetic patients reduced progression to diabetic nephropathy comparable to what has previously been reported in intervention trials.

Cardiovascular morbidity and early mortality cluster in parents of type 1 diabetic patients with diabetic nephropathy.

OBJECTIVE: A familial predisposition was proposed to be a determinant of the increased morbidity and mortality from cardiovascular disease in type 1 diabetic patients with diabetic nephropathy. The insertion allele of an insertion/deletion polymorphism in the ACE (ACE/ID) gene seems to protect against coronary heart disease in nondiabetic and diabetic subjects. The aim of the present study was to evaluate these hypotheses in parents of a large group of type 1 diabetic patients with and without diabetic nephropathy. RESEARCH DESIGN AND METHODS: We investigated cardiovascular morbidity and mortality of parents of 163 type 1 diabetic patients with nephropathy and parents of 163 sex- and age-matched normoalbuminuric patients with type 1 diabetes. RESULTS: Kaplan-Meier curves showed that total parental mortality was significantly increased in parents of type 1 diabetic patients with nephropathy (121 of 244 [ approximately 50%] ) as compared with parents of normoalbuminuric type 1 diabetic patients (119 of 269 [approximately 44%]) (P = 0.008 [log-rank test]) partially due to an increase in cardiovascular deaths (48 of 244 [approximately 20%] vs. 42 of 269 [approximately 16%], P<0.05). In addition, more patients with nephropathy, as compared with the normoalbuminuric group, had at least one parent with fatal/nonfatal cardiovascular disease (46% [95% CI 38-54] vs. 36% [28-44], P = 0.05). Fathers of patients homozygous for the I-allele of the ACE/ID polymorphism had significantly less myocardial infarction as compared with other genotypes (P = 0.03), regardless of the nephropathic state of the offspring. CONCLUSIONS: Cardiovascular morbidity and early mortality clusters in parents of type 1 diabetic patients with diabetic nephropathy The ACE/ID polymorphism helps explain the increased morbidity from cardiovascular disease.

Biochemical characterization of the heteromeric Bacillus subtilis dihydroorotate dehydrogenase and its isolated subunits.

Bacillus subtilis dihydroorotate dehydrogenase (DHOD) consists of two subunits, PyrDI (M(r) = 33,094) and PyrDII (M(r) = 28,099). The two subunits were overexpressed jointly and individually and purified. PyrDI was an FMN-containing flavoprotein with an apparent native molecular mass of 85,000. Overexpressed PyrDII formed inclusion bodies and was purified by refolding and reconstitution. Refolded PyrDII bound 1 mol FAD and 1 mol [2Fe-2S] per mol PyrDII. Coexpression and purification of PyrDI and PyrDII yielded a native holoenzyme complex with an apparent native molecular mass of 114,000 that indicated a heterotetramer (PyrDI(2)PyrDII(2)). The holoenzyme possessed dihydroorotate:NAD(+) oxidoreductase activity and could also reduce menadione and artificial dyes. Purified PyrDI also possessed DHOD activity but could not reduce NAD(+). Compared to PyrDI, the holoenzyme had a more than 20-fold smaller K(m) value for dihydroorotate, an approximately 50-fold smaller K(i) value for orotate, and approximately 500-fold greater catalytic efficiency. Dihydroorotate:NAD(+) oxidoreductase activity could be recovered by mixing the purified subunits. Recovered activity showed a clear dependence on FAD reconstitution of PyrDII but not on reconstitution with FeS clusters. PyrDII had a strong preference for FAD over FMN and bound it with an estimated K(d) value of 4.9 +/- 0.8 nM. pyrDII mutants containing alanine substitutions of the cysteine ligands to the [2Fe-2S] cluster failed to complement the pyr bradytrophy of a DeltapyrDII strain, indicating a requirement for the FeS cluster in PyrDII for normal function in vivo.

Increased sympathetic activity during sleep and nocturnal hypertension in Type 2 diabetic patients with diabetic nephropathy.

AIMS: To elucidate the putative factors involved in the blunted nocturnal blood pressure reduction in hypertensive Type 2 diabetic patients with diabetic nephropathy. METHODS: Extracellular fluid volume and fluid shift from interstitial to plasma volume (haematocrit), sympathetic nervous activity (plasma noradrenaline and adrenaline) and the internal 'body clock' (serum melatonin) were investigated in 31 hypertensive Type 2 diabetes mellitus (DM) patients with diabetic nephropathy (24 males, age 60 (45-73) years). All variables, except extracellular volume, were measured repeatedly with the patients lying awake in bed from 21:30 to 23:00 h (baseline) and during sleep from 23:00 to 07:00 h. Using the median nocturnal blood pressure reduction (8.4%) as a guide, the patients were divided into groups; group 1 with the highest and group 2 with the lowest nocturnal blood pressure reduction. RESULTS: Haematocrit decreased from baseline to the sleep period in group 1 by a mean (95% confidence interval (CI)) of 1.7 (0.3-3.1)%, but it increased by 0.5 (-1.0-1.9)% in group 2, mean difference (95% CI), -2.1 (-4.0 to -0.2)% (P = 0.029). Noradrenaline decreased from baseline to the sleep period, mean (95% CI), by 13.3 (0.0-25.0)% in group 1 but rose by 7.7 (-9.7-28.4)% in group 2, mean difference (95% CI), -19.6 (-35-0.0)% (P = 0.049). The nocturnal blood pressure change correlated to the nocturnal change in both noradrenaline (r = 0.51, P = 0.004) and haematocrit (r = 0.42, P = 0.018). Adrenaline remained constant in both groups. Extracellular fluid volume and plasma melatonin levels were comparable in the two groups. CONCLUSION: Sustained adrenergic activity during sleep is associated with blunted nocturnal blood pressure reduction in hypertensive Type 2DM patients with diabetic nephropathy, probably mediated through a lack of peripheral vasodilatation whereas changes in extracellular fluid volume distribution and melatonin secretion have no impact.

Natural course of kidney function in Type 2 diabetic patients with diabetic nephropathy.

AIMS: To determine the natural course of kidney function and to evaluate the impact of putative progression promoters in Caucasian Type 2 diabetes mellitus (DM) patients with diabetic nephropathy who had never received any antihypertensive treatment. METHODS: A long-term observational study of 13 normotensive to borderline hypertensive Type 2 DM patients with diabetic nephropathy. Glomerular filtration rate (GFR) was measured approximately every year (51Cr-EDTA plasma clearance technique). Albuminuria, blood pressure (BP) and haemoglobin A1c (HbA1c) was determined 2-4 times per year and serum cholesterol every second year. RESULTS: The patients (12 males/one female), age 56+/-9 (mean +/- SD) years, with a known duration of diabetes of 10+/-6 years, were followed for 55 (24-105) (median (range)) months. GFR decreased from 104 (50-126) to 80 (39-112) ml x min(-1) x 1.73 m(-2) (P = 0.002) with a median rate of decline of 4.5 (-0.4 to 12) ml x min(-1) x year(-1). During follow-up, albuminuria rose from 494 (301-1868) to 908 (108-2169) mg/24 h (P = 0.25), while BP, HbA1c and serum cholesterol remained essentially unchanged. In univariate analysis the rate of decline in GFR did not correlate significantly with neither baseline nor mean values during follow-up of BP, albuminuria, HbA1c and serum cholesterol. CONCLUSIONS: Our study suggests that normotensive to borderline hypertensive Type 2 DM patients with diabetic nephropathy have a rather slow decline in kidney function, but we did not unravel the putative progression promoters responsible for the variation in rate of decline in GFR.

Cyclosporine nephrotoxicity in type 1 diabetic patients. A 7-year follow-up study.

OBJECTIVE: To evaluate kidney function 7 years after the end of treatment with cyclosporine A (CsA) (initial dosage of 9.3 tapered off to 7.0 mg.kg-1.day-1) in young patients (mean age 20 years) with newly diagnosed type 1 diabetes participating in a randomized, double-blind, placebo-controlled CsA trial. RESEARCH DESIGN AND METHODS: In this study, 21 patients received CsA for 12.5 +/- 4.0 months (mean +/- SD) and 19 patients received placebo for 14.4 +/- 3.8 months. The two groups were similar with regard to mean arterial blood pressure (BP), urinary albumin excretion rate (UAER), serum creatinine, and estimated glomerular filtration rate (GFR [Cockcroft and Gault]) at initiation of CsA treatment (baseline). HbA1c (mean +/- SEM) during 7 years of follow-up was also the same: 8.7 +/- 0.4 vs. 8.3 +/- 0.4% in the CsA and placebo groups, respectively. RESULTS: During the 7 years after cessation of study medication, two CsA group patients and one control patient were lost to follow-up. One placebo-treated patient developed IgA nephropathy (biopsy proven) and was excluded. Four CsA-treated patients developed persistently elevated UAER > 30 mg/24 h (n = 3 with microalbuminuria), whereas all the 17 placebo-treated patients had normal UAER (< 30 mg/24 h) after 7 years of follow-up. At the end of follow-up, the CsA group had a more pronounced rise in UAER: 2.5-fold (95% CI 1.4-4.5) higher than baseline value vs. 1.1-fold (0.7-1.7) in the placebo-treated group (P < 0.05). Estimated GFR (ml.min-1.1.73 m-2) declined from baseline to end of follow-up (1994) by 6.3 +/- 6.0 in the former CsA group, whereas it rose by 7.4 +/- 5.0 in the placebo group (P = 0.05). In 1994, 24-h blood pressure was nearly the same: 131/77 +/- 4/2 vs. 127/75 +/- 2/2 mmHg (NS) in the CsA and placebo groups, respectively. Five randomly selected CsA-treated patients had a kidney biopsy performed shortly after the CsA treatment was stopped. Interstitial fibrosis/tubular atrophy and/or arteriolopathy were present in two subjects who both subsequently developed persistent microalbuminuria. CONCLUSIONS: The results of our 7-year follow-up study suggested that short-lasting CsA treatment in young, newly diagnosed type 1 diabetic patients accelerated the rate of progression in UAER and tended to induce a loss in kidney function. Longer term follow-up is mandatory to clarify whether CsA-treated patients are at increased risk of developing clinical nephropathy.

Effects of nisoldipine and lisinopril on left ventricular mass and function in diabetic nephropathy.

OBJECTIVE: To compare the effects of the calcium channel blocker, nisoldipine, and the ACE inhibitor, lisinopril, on left ventricular mass (LVM) and systolic function in type 1 diabetic patients with diabetic nephropathy. RESEARCH DESIGN AND METHODS: M-mode echocardiography was performed in 50 hypertensive type 1 diabetic patients with diabetic nephropathy enrolled in a 1-year, randomized, double-blind, parallel study of antihypertensive treatment with nisoldipine CC (20-40 mg/day) or lisinopril (10-20 mg/day). Ambulatory 24-h blood pressure was measured with the Takeda TM 2420 device (A & D, Tokyo, Japan) every 3 months. Three patients dropped out and seven patients were excluded due to technical difficulties. RESULTS: The 24-h diastolic blood pressure was reduced from 83 to 80 mmHg in the nisoldipine group (P = 0.06) and from 85 to 80 mmHg in the lisinopril group (P = 0.02). The decline in systolic blood pressure was not significant with any of the two treatments, and no difference in reduction of blood pressure was seen between groups. LVM corrected for body surface area (LVMI) was comparable between groups at baseline and increased from 96 +/- 5 to 107 +/- 6 g/m2 (mean +/- SEM; P = 0.007) in the nisoldipine group and from 95 +/- 4 to 103 +/- 5 g/m2 (P = 0.03) in the lisinopril group. The mean difference between the change in LVMI in the two groups was 2.9 (95% CI 6.8 to 12.7) g/m2. The prevalence of left ventricular hypertrophy rose from 18 (95% CI 6-30) to 30% (16-44) during the study period. A multiple linear regression analysis revealed that after 1 year of treatment, LVMI increased with higher systolic blood pressure level and declining glomerular filtration rate (R2 = 0.25). Fractional shortening was within normal range at baseline, 42 +/- 1 vs. 41 +/- 1% with nisoldipine and lisinopril, respectively, and did not change during follow-up. CONCLUSIONS: Antihypertensive treatment with nisoldipine or lisinopril to bring diastolic blood pressure level within the normal target range does not hinder a rise in LVMI in type 1 diabetic patients with diabetic nephropathy.

The crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A complexed with the enzyme reaction product throws light on its enzymatic function.

Dihydroorotate dehydrogenases (DHODs) catalyze the oxidation of (S)-dihydroorotate to orotate, the fourth step and only redox reaction in the de novo biosynthesis of pyrimidine nucleotides. A description is given of the crystal structure of Lactococcus lactis dihydroorotate dehydrogenase A (DHODA) complexed with the product of the enzyme reaction orotate. The structure of the complex to 2.0 A resolution has been compared with the structure of the native enzyme. The active site of DHODA is known to contain a water filled cavity buried beneath a highly conserved and flexible loop. In the complex the orotate displaces the water molecules from the active site and stacks above the DHODA flavin isoalloxazine ring, causing only small movements of the surrounding protein residues. The orotate is completely buried beneath the protein surface, and the orotate binding causes a significant reduction in the mobility of the active site loop. The orotate is bound by four conserved asparagine side chains (Asn 67, Asn 127, Asn 132, and Asn 193), the side chains of Lys 43 and Ser 194, and the main chain NH groups of Met 69, Gly 70, and Leu 71. Of these the Lys 43 side chain makes hydrogen bonds to both the flavin isoalloxazine ring and the carboxylate group of the orotate. Potential interactions with bound dihydroorotate are considered using the orotate complex as a basis for molecular modeling. The role of Cys 130 as the active site base is discussed, and the sequence conservation of the active site residues across the different families of DHODs is reviewed, along with implications for differences in substrate binding and in the catalytic mechanisms between these families.

Beneficial impact of ramipril on left ventricular hypertrophy in normotensive nonalbuminuric NIDDM patients.

OBJECTIVE: To evaluate the effect of the ACE inhibitor ramipril as compared with placebo on left ventricular mass index (LVMI) in normotensive, nonalbuminuric NIDDM patients with left ventricular hypertrophy (LVH). Patients with NIDDM are characterized by excessive cardiovascular morbidity and mortality, and LVH, an independent risk factor for cardiac events, is often present in NIDDM patients. RESEARCH DESIGN AND METHODS: A total of 38 normotensive, nonalbuminuric (albuminuria < 100 mg/24 h) NIDDM patients with LVH (LVMI > 131 g/m2 in men and > 100 g/m2 in women) were enrolled in a 6-month randomized, double-blind parallel group study to compare the effects of ramipril (5 mg/day) with placebo on LVMI (echocardiography, Vingmed CFM725, Diasonics Sonotron), QTc dispersion determined as the interlead variation in QTc interval on standard electrocardiogram (ECG), and 24-h ambulatory blood pressure (A&D TM2420, Tokyo, Japan). A total of 16 ramipril (10 men, 60 +/- 9 years [mean +/- SD]) and 15 placebo-treated (8 men, 55 +/- 10 years) patients completed the study, and their data are presented. RESULTS: Ambulatory blood pressure was almost identical at baseline (132/76 +/- 3/1 vs. 133/74 +/- 5/2 mmHg [mean +/- SEM]) and remained stable during follow-up (134/76 +/- 3/1 vs. 136/74 +/- 6/2 mmHg) in the ramipril and placebo group, respectively. LVMI was comparable at baseline (137.1 +/- 7.0 vs. 129.6 +/- 3.7 g/m2) in the ramipril and placebo group, respectively, and decreased significantly more in the ramipril group as compared with the placebo group (17.6 +/- 3.0 vs. 5.7 +/- 4.6 g/m2, respectively, 11.9 [0.7-23.1] g/m2, mean difference [95% CI]; P = 0.037). QTc dispersion was comparable at baseline (60.2 [5.5] vs. 64.1 [6.5] ms) and did not change significantly during follow-up: -2.5 [7.0] vs. -12.2 [9.5] ms; mean difference 9.8 (-14.2 to 33.8 ms) in the ramipril and placebo group, respectively. CONCLUSIONS: Ramipril induces regression of LVH in normotensive, nonalbuminuric NIDDM patients, independent of reduction in systemic blood pressure.

Predisposition to essential hypertension and development of diabetic nephropathy in IDDM patients.

Conflicting results have been reported on the relationship between familial predisposition to hypertension and development of diabetic nephropathy in IDDM. In our case-control study, we assessed the prevalence of hypertension among parents of 73 IDDM patients with diabetic nephropathy (DN+; persistent albuminuria > 200 microg/min or > 300 mg/24 h) and 73 IDDM patients without diabetic nephropathy (DN-; urinary albumin excretion < 20 microg/min or < 30 mg/24 h). Arterial hypertension, defined as antihypertensive therapy or a 24-h ambulatory blood pressure (SpaceLabs 90207) > or = 135/85 mmHg, was present in 57% of parents of DN+ patients compared with 41% of parents of DN- patients (P = 0.034; difference 16% [95% CI 1.3-29.6%]). In addition, the cumulative incidence of hypertension was higher among parents of DN+ patients (log-rank test P < 0.001), with a shift toward younger age at onset of hypertension in this group. However, the difference in prevalence of parental hypertension was not evident using office blood pressure measurements (64 vs. 57%; NS; difference 7% [-5.8-20%). Furthermore, patients with DN+ and with antihypertensive therapy in both parents were themselves more frequently treated for hypertension than were patients with DN+ and without parental treatment for hypertension (100 vs. 61%; P = 0.034; difference 39% [21-57%]). In conclusion, familial predisposition to essential hypertension increases the risk of diabetic nephropathy and may also contribute to the development of systemic hypertension in patients with IDDM and diabetic nephropathy.

Lisinopril improves endothelial dysfunction in hypertensive NIDDM subjects with diabetic nephropathy.

Endothelial dysfunction is a prevalent phenomenon in non-insulin dependent diabetic (NIDDM) patients with hypertension and albuminuria, and may contribute to the development and progression of cardiovascular disease, which is the main cause of the high morbidity and mortality observed in these patients. Therefore the aim of our study was to evaluate whether inhibition of angiotensin-converting enzyme (with lisinopril 10-20 mg day-1) could ameliorate endothelial dysfunction more than reducing blood pressure with conventional antihypertensive treatment (atenolol 50-100 mg day-1), usually in combination with a diuretic. We performed a 12-month prospective, randomized, double-blind, parallel study in 43 hypertensive NIDDM patients with diabetic nephropathy (21 treated with lisinopril and 22 with atenolol). The following variables were measured: 24-h ambulatory blood pressure (ABP); transcapillary escape rate of albumin (TERalb; i.e. initial disappearance of intravenously injected 125I-labelled human serum albumin); serum concentrations of von Willebrand factor (vWF), using ELISA, and urinary albumin excretion rate (UAE). Data are presented for 32 patients (16 lisinopril and 16 atenolol; age 60 years, SD 8; 25 males) out of 35 who completed the study and had valid measurements of TERalb. At baseline the two groups were comparable; TERalb (8.5 (SEM 0.6) vs. 7.2 (0.4)%); vWF (2.09 (range 0.82-4.34) vs. 1.97 (0.95-3.86) IU ml-1; UAE 916 (x/divided by antilog SEM 1.3) vs. 1444 (1.2), and mean ABP 110 (SEM 3) vs. 113 (2) mmHg, in the lisinopril and atenolol group, respectively. During follow up, the mean ABP was equally reduced in the lisinopril and atenolol group, by 12 (SEM 2) vs. 10 (2) mmHg, respectively, TERalb decreased in the lisinopril group by 0.6 (SEM 0.7)%, whereas it increased in the atenolol group 1.5 (0.5)%; the mean difference was 2.2% (95% CI, 0.5 to 3.9; p = 0.015). UAE was reduced by 45% (95% CI, 25 to 60) in the lisinopril group vs. 10% (-15 to 30) in the atenolol group (p = 0.014). Serum vWF was not changed during follow up in either group. Our study suggests that lisinopril has both reno- and vasculoprotective properties in hypertensive NIDDM patients with diabetic nephropathy.

Left ventricular hypertrophy in non-insulin-dependent diabetic patients with and without diabetic nephropathy.

The aim of our cross-sectional case-control study was to evaluate putative mechanisms of the increased cardiac morbidity and mortality in NIDDM patients with or without diabetic nephropathy. Fifty-one NIDDM patients with diabetic nephropathy (38 males, age 61 +/- 8 years, group 1), 53 NIDDM patients with normoalbuminuria (42 males, 61 +/- 7 years, group 2), and 22 non-diabetic control subjects (15 males, 58 +/- 8 years, group 3) were investigated. Previous antihypertensive treatment was withdrawn 2 weeks before the study. Left ventricular mass index (LVMI) and systolic function were determined by echocardiography. LVMI was elevated, mean +/- SE, in group 1: 157 +/- 6 g m(-2), and in group 2: 139 +/- 7 g m(-2), as compared with group 3: 95 +/- 5 g m(-2) (p < 0.001, for both), and in group 1 as compared with group 2 (p = 0.05). The prevalence of left ventricular hypertrophy (LVH) (LVMI > 131 g m(-2) in men and > 100 gm(-2) in women) was much higher in group 1: 75% (95% CI, 60-86), and group 2: 51% (95% CI, 37-65), as compared with group 3: 9% (95% CI, 1-29) (p < 0.001, for both), and in group 1 as compared with group 2 (p < 0.01). Shortening fraction of the left ventricle, % +/- SE, was relatively reduced in group 1: 32.5 +/- 1.1%, and group 2: 33.4 +/- 1.1%, as compared with group 3: 41.2 +/- 1.2% (p < 0.01, for both). In a subgroup of 26 normoalbuminuric normotensive NIDDM patients, LVMI was higher than in 14 normotensive non-diabetic control subjects: 137 +/- 10 g m(-2) vs 96 +/- 7 g m(-2), respectively (p < 0.005). The prevalence of LVH was 42% (95% CI, 23-63) and 14% (95% CI, 2-43) (p = 0.07) in these two groups, respectively. In conclusion, normotensive and hypertensive NIDDM patients with and without diabetic nephropathy frequently suffer from LVH and relatively reduced systolic function which may constitute independent risk factors for fatal and non-fatal cardiac events.

Long-term effect of lisinopril and atenolol on kidney function in hypertensive NIDDM subjects with diabetic nephropathy.

The aim of our study was to evaluate whether inhibition of ACE (lisinopril 10-20 mg/day) can reduce the rate of decline in kidney function more than reducing blood pressure with conventional antihypertensive treatment (atenolol 50-100 mg/day), usually in combination with a diuretic. We performed a prospective, randomized, parallel study for 42 months, double blind for the first 12 months and single blind thereafter. Forty-three (21 lisinopril and 22 atenolol) hypertensive NIDDM patients with diabetic nephropathy were enrolled. Data from 36 patients (17 lisinopril and 19 atenolol, 60 +/- 7 years of age, 27 men) who completed at least 12 months of the study period are presented. At baseline, the two groups were comparable: glomerular filtration rate (51Cr-EDTA plasma clearance) was 75 +/- 6 and 74 +/- 8 ml x min(-1) x 1.73 m(-2), mean 24-h ambulatory blood pressure (A&D TM2420) was 110 +/- 3 and 114 +/- 2 mmHg, and 24-h urinary albumin excretion rate was 961 (range 331-5,727) and 1,578 (476-5,806) mg/24 h in the lisinopril and atenolol groups, respectively. The mean follow-up time was similar, 37 and 35 months in the lisinopril and atenolol groups, respectively. Mean ambulatory blood pressure was equally reduced in the two groups, 12 +/- 2 and 10 +/- 2 mmHg in the lisinopril and atenolol groups, respectively. Glomerular filtration rate declined in a biphasic manner with a faster initial (0 to 6 months) change of 1.25 +/- 0.49 and 0.81 +/- 0.29 ml x min(-1) x month(-1) followed by a slower sustained decline (6 to 42 months) of 0.59 +/- 0.10 and 0.54 +/- 0.13 ml x min(-1) x month(-1) in the lisinopril and atenolol groups, respectively. No significant differences were observed in either initial or sustained decline in glomerular filtration rate between the two groups. Urinary albumin excretion was reduced (% reduction of baseline) more in the lisinopril than in the atenolol group, at 55 (95% CI 29-72) and 15% (-13 to 34), respectively (P = 0.01). In conclusion, the relentless decline in kidney function characteristically found in hypertensive NIDDM patients with diabetic nephropathy can be reduced equally effectively by two antihypertensive treatments, the beta-blocker atenolol and the ACE inhibitor lisinopril.

White coat hypertension in NIDDM patients with and without incipient and overt diabetic nephropathy.

OBJECTIVE: Early data have suggested a high prevalence of white coat hypertension (approximately 50%) in NIDDM patients. To study this phenomenon further, we determined the prevalence of white coat hypertension in NIDDM patients with normo- or microalbuminuria or with diabetic nephropathy. RESEARCH DESIGN AND METHODS: Three groups of hypertensive NIDDM patients (repeated clinic blood pressure > 140/90 mmHg or antihypertensive treatment) attending the Steno Diabetes Center were investigated in a cross-sectional study. Group 1 had normoalbuminuria (a urinary albumin excretion [UAE] rate < 30 mg/24 h, n = 30, age 61 +/- 7 [mean +/- SD] years, 20 men), group 2 had microalbuminuria (UAE rate 30-300 mg/24 h, n = 51, age 55 +/- 7 years, 35 men), and group 3 had diabetic nephropathy (UAE rate > 300 mg/24 h, n = 47, 62 +/- 7 years, 36 men). If given, all previous antihypertensive medication was withdrawn at least 2 weeks before the study (48%). The prevalence of white coat hypertension (clinic hypertension with normal blood pressure values at home) was determined by comparison of clinic blood pressure (Hawksley Random sphygmomanometer) and the ambulatory daytime (7:00 A.M. to 11:00 P.M.) blood pressure (A&D TM2420). By applying established criteria, white coat hypertension was confirmed if daytime blood pressure was < 135/85 mmHg. RESULTS: The clinic blood pressure was 155/86 (SE 3/2) mmHg, 156/89 (2/1) mmHg, and 171/90 (3/2) mmHg in group 1, 2, and 3, respectively (P < 0.05 comparing group 3 with groups 1 and 2). The prevalence of white coat hypertension was significantly higher in group 1 as compared with groups 2 and 3, 23% (95% CI 10-42) vs. 8% (2-19) and 9% (2-20) (P < 0.05), with no difference between the latter two groups. CONCLUSIONS: The prevalence of white coat hypertension in normoalbuminuric NIDDM patients resembles that observed in nondiabetic subjects with essential hypertension, whereas the prevalence is significantly lower in NIDDM patients with incipient or overt diabetic nephropathy, suggesting a difference between primary and secondary hypertension.

Differences between nisoldipine and lisinopril on glomerular filtration rates and albuminuria in hypertensive IDDM patients with diabetic nephropathy during the first year of treatment.

Our objective was to compare the effect of a long-acting calcium antagonist (nisoldipine) versus an ACE inhibitor (lisinopril) on albuminuria, arterial blood pressure, and glomerular filtration rate (GFR) in hypertensive IDDM patients with diabetic nephropathy. We performed a 1-year, double-blind, double-dummy, randomized, controlled study comparing nisoldipine (20-40 mg once daily) with lisinopril (10-20 mg once daily) in 52 hypertensive IDDM subjects with diabetic nephropathy. Three patients dropped out, and results for the remaining 49 (25 nisoldipine, 24 lisinopril) are presented. Diuretics were required in 10 nisoldipine- and 8 lisinopril-treated patients. Every 3 months, 24-h ambulatory blood pressure (TM2420, A&D, Tokyo, Japan) and albuminuria in three 24-h samples (enzyme immunoassay) were measured; GFR (51Cr-EDTA plasma clearance) was recorded every 6 months. Mean arterial blood pressure (24 h) was reduced from (mean +/- SE) 108 +/- 3 mmHg at baseline to 101 +/- 2 in average during treatment in the lisinopril group and from 105 +/- 2 to 103 +/- 2 in the nisoldipine group (P = 0.06 comparing changes in the two groups). Albuminuria was reduced 47% (95% CI 21-65) in the lisinopril group versus an increase of 11% (-3 to 27) in the nisoldipine group (P = 0.001). Fractional albumin clearance was reduced 37% (95% CI 4-59%) in the lisinopril versus an increase of 35% (8-69%) in the nisoldipine group (P < 0.01). GFR decreased from 85 +/- 5 ml x min(-1) x 1.73 m(-2) to 73 +/- 5 in the lisinopril group and from 84 +/- 6 to 80 +/- 7 in the nisoldipine group (P < 0.05). The effect of study medication on albuminuria and GFR was independent of changes in systemic blood pressure and baseline variables in multiple regression analyses. In summary, lisinopril reduced albuminuria, but also GFR, to a greater extent than did nisoldipine in hypertensive IDDM patients with diabetic nephropathy during the 1st year of treatment. Longer follow-up is required to clarify whether these drugs have different renoprotective effects.

The crystal structure of the flavin containing enzyme dihydroorotate dehydrogenase A from Lactococcus lactis.

BACKGROUND: . Dihydroorotate dehydrogenase (DHOD) is a flavin mononucleotide containing enzyme, which catalyzes the oxidation of (S)-dihydroorotate to orotate, the fourth step in the de novo biosynthesis of pyrimidine nucleotides. Lactococcus lactis contains two genes encoding different functional DHODs whose sequences are only 30% identical. One of these enzymes, DHODA, is a highly efficient dimer, while the other, DHODB, shows optimal activity only in the presence of an iron-sulphur cluster containing protein with which it forms a complex tetramer. Sequence alignments have identified three different families among the DHODs: the two L. lactis enzymes belong to two of the families, whereas the enzyme from E. coli is a representative of the third. As no three-dimensional structures of DHODs are currently available, we set out to determine the crystal structure of DHODA from L. lactis. The differences between the two L. lactis enzymes make them particularly interesting for studying flavoprotein redox reactions and for identifying the differences between the enzyme families. RESULTS: . The crystal structure of DHODA has been determined to 2.0 resolution. The enzyme is a dimer of two crystallographically independent molecules related by a non-crystallographic twofold axis. The protein folds into and alpha/beta barrel with the flavin molecule sitting between the top of the barrel and a subdomain formed by several barrel inserts. Above the flavin isoalloxazine ring there is a small water filled cavity, completely buried beneath the protein surface and surrounded by many conserved residues. This cavity is proposed as the substrate-binding site. CONCLUSIONS: . The crystal structure has allowed the function of many of the conserved residues in DHODs to be identified: many of these are associated with binding the flavin group. Important differences were identified in some of the active-site residues which vary across the distinct DHOD families, implying significant mechanistic differences. The substrate cavity, although buried, is located beneath a highly conserved loop which is much less ordered than the rest of the protein and may be important in giving access to the cavity. The location of the conserved residues surrounding this cavity suggests the potential orientation of the substrate.