Multilocus linkage of familial hyperkalaemia and hypertension, pseudohypoaldosteronism type II, to chromosomes 1q31-42 and 17p11-q21.

Essential hypertension is a common multifactorial trait. The molecular basis of a number of rare diseases that after blood pressure in humans has been established, identifying pathways that may be involved in more common forms of hypertension. Pseudohypoaldosteronism type II (PHAII, also known as familial hyperkalaemia and hypertension or Gordon's syndrome; OMIM #145260), is characterized by hyperkalaemia despite normal renal glomerular filtration, hypertension and correction of physiologic abnormalities by thiazide diuretics. Mild hyperchloremia, metabolic acidosis and suppressed plasma renin activity are variable associated findings. The pathogenesis of PHAII is unknown, although clinical studies indicate an abnormality in renal ion transport. As thiazide diuretics are among the most efficacious agents in the treatment of essential hypertension, understanding the pathogenesis of PHAII may be of relevance to more common forms of hypertension. Analysis of linkage in eight PHAII families showing autosomal dominant transmission demonstrates locus heterogeneity of this trait, with a multilocus lod score of 8.1 for linkage of PHAII to chromosomes 1q31-q42 and 17p11-q21. Interestingly, the chromosome-17 locus overlaps a syntenic interval in rat that contains a blood pressure quantitative trait locus (QTL). Our findings provide a first step toward identification of the molecular basis of PHAII.

Nateglinide combination therapy with basal insulin and metformin in patients with Type 2 diabetes.

AIMS: To compare the effect of adding nateglinide or placebo on postprandial glucose excursions (PPGEs), glycated haemoglobin (HbA(1c)), diurnal glucose profiles and hypoglycaemia in patients with Type 2 diabetes treated with the combination of basal insulin and metformin. RESEARCH DESIGN AND METHODS: This was an investigator-initiated, double-blind, randomized, parallel-group, study in five centres. Patients with Type 2 diabetes (n = 88, age 56.0 +/- 0.9 years, duration of diabetes 9.4 +/- 0.5 years, HbA(1c) 7.8 +/- 0.1%, body mass index 32.4 +/- 0.5 kg/m(2)) treated with basal insulin and metformin entered a 24-week period, during which basal insulin was titrated to optimize glucose control. Thereafter, the patients were randomized to receive either nateglinide (120 mg three times daily) or placebo before their main meals for 24 weeks. RESULTS: During the optimization period, HbA(1c) decreased by -0.3 +/- 0.1 and -0.4 +/- 0.2% (NS) and insulin doses increased by 10.0 IU (2.0-32.0) [0.09 IU/kg (0.02-0.34)] and 10.0 IU (0.0-19.0) [0.11 IU/kg (0.0-0.25)] (NS) in the nateglinide and placebo groups. Mean postprandial glucose during weeks 20-24 averaged 9.0 +/- 0.3 and 10.0 +/- 0.3 mmol/l in the nateglinide and placebo groups (P = 0.025) and mean PPGE averaged 2.4 +/- 0.2 and 3.1 +/- 0.2 mmol/l, respectively (P = 0.019). At 24 weeks as compared with 0 weeks, mean HbA(1c) had decreased by 0.41 +/- 0.12% in the nateglinide group and by 0.04 +/- 0.12% in the placebo group (P = 0.023). The frequency of confirmed, symptomatic hypoglycaemia was 7.7 episodes/patient-year vs. 4.7 episodes/patient-year in the nateglinide and placebo groups (P = 0.031). CONCLUSIONS: Addition of a short-acting insulin secretagogue at main meals improves postprandial hyperglycaemia during combination therapy with basal insulin and metformin, but increases the frequency of hypolycaemia.

A novel polymorphism of apolipoprotein A-IV is the result of an asparagine to serine substitution at residue 127.

We have identified a hitherto unknown genetic polymorphism of apolipoprotein A-IV (apoA-IV). The molecular basis for this polymorphism is an A to G substitution at nucleotide 1687 resulting in an Asn to Ser change of amino acid 127. The frequencies of the two apoA-IV alleles (designated apoA-IV127Asn and apoA-IV127Ser), determined by Hin c II restriction analysis of PCR amplified exon three of the apoA-IV gene, were 0.788 and 0.212, respectively, in a Finnish population sample. Allele frequencies of another polymorphism due to a Thr to Ser substitution at amino acid 347 were determined using Hinf I restriction analysis. The allele frequencies were 0.823 for apoA-IV347Thr and 0.177 for apoA-IV347Ser. None of the apoA-IV polymorphisms (apoA-IV127:Asn----Ser, apoA-IV347:Thr----Ser and apoA-IV360:Gln----His) had any effect on plasma lipid and lipoprotein concentrations in cohorts of dyslipidemic men and in a population sample of normolipidemic controls. There was also no association between the history of previous myocardial infarction and any of the apoA-IV alleles.

Serum lipoproteins in patients with myocardial infarction.

The lipid and lipoprotein profile was examined in male patients with acute myocardial infarction (AMI) at the time of infarction (group A) and in male patients who had survived AMI 2-3 years before the study (group B), and compared to that of healthy controls. The myocardial infarction (MI) patients exhibited similar total cholesterol and LDL-cholesterol levels as the controls. However, the LDL mass concentration was higher in patients than in controls (P less than 0.01 for group A, P less than 0.001 for group B). In composition, patients' LDL in both groups was rich in protein and triglycerides but poor in cholesterol. The compositional changes in patient LDL were evident at all levels of LDL-cholesterol. The mean total HDL and HDL2 mass concentrations were lower in patients than in controls (P less than 0.001 for both groups), but there was no difference in HDL3 levels. Upon admission to hospital the patients with AMI at the time of examination (group A) had higher serum total triglyceride concentration than controls, but on the fasting morning samples serum triglyceride and VLDL lipid levels did not differ between patients and controls. Patients who had survived AMI 2-3 years prior to study (group B) exhibited higher serum total triglyceride and VLDL levels than the control subjects. On stepwise discriminant analysis, HDL2 protein concentration was the single best variable for distinguishing between patients and controls. The most powerful discriminatory parameter was the HDL/LDL protein ratio or the HDL2/LDL protein ratio.

Arg506Gln factor V mutation (factor V Leiden) in patients with ischaemic cerebrovascular disease and survivors of myocardial infarction.

The point mutation Arg506- > Gln of factor V was recently shown to be an important and relatively common genetic cause of venous thromboembolism. Using a DNA technique based on polymerase chain reaction, we surveyed the blood samples of 236 patients with ischaemic stroke or a transient ischaemic attack, 122 survivors of myocardial infarction and 137 control subjects for the presence of this mutation. Although the frequency of the factor V mutation in patients with arterial disease (4.5%) was not significantly different from that in healthy blood donors (2.9%), a carrier status for this mutant gene was associated with symptoms of migraine and relatively mild angiographic abnormalities among patients with cerebrovascular disease. A more extensive study addressing the occurrence and significance of the mutant factor V mutation in patients with vasospastic cerebrovascular diseases seems to be warranted.

Insulin glargine or NPH combined with metformin in type 2 diabetes: the LANMET study.

AIMS/HYPOTHESIS: In type 2 diabetic patients we compared 9 months of combination therapy with insulin glargine and metformin with 9 months of NPH insulin combined with metformin. The primary focus was changes in HbA(1c); secondary focus was diurnal glucose profiles and symptomatic hypoglycaemia. METHODS: In this investigator-initiated open, parallel-group clinical trial involving seven centres, 110 insulin-naive type 2 diabetic patients with poor glycaemic control (HbA(1c) >or=8.0%) on oral hypoglycaemic agents (90% using sulfonylurea plus metformin) were randomised to receive bedtime insulin glargine with metformin (G+MET) or bedtime NPH with metformin (NPH+MET) for 36 weeks. The patients were taught how to self-adjust their insulin dose and use a modem to send the results of home glucose monitoring to treatment centres. The goal was to achieve a fasting plasma glucose (FPG) of 4.0 to 5.5 mmol/l in both groups. RESULTS: During the last 12 weeks, FPGs averaged 5.75+/-0.02 and 5.96+/-0.03 mmol/l (p<0.001) and insulin doses were 68+/-5 and 70+/-6 IU/day (0.69+/-0.05 and 0.66+/-0.04 IU kg(-1) day(-1), NS) in the G+MET and NPH+MET groups, respectively. At 36 weeks, mean HbA(1c) was 7.14+/-0.12 and 7.16+/-0.14%, respectively (NS). Symptomatic, but not confirmed symptomatic, hypoglycaemia was significantly lower during the first 12 weeks in the G+MET group (4.1+/-0.8 episodes/patient-year) than in the NPH+MET group (9.0+/-2.3 episodes/patient-year, p<0.05), but not significantly different thereafter. Glucose levels before dinner were higher in the NPH+MET group (10.1+/-0.3 mmol/l) than in the G+MET group (8.6+/-0.3 mmol/l, p=0.002) throughout the 36-week study. With regard to baseline characteristics such as initial glycaemia or C-peptide, there was no difference between patients who achieved good glycaemic control (HbA(1c) <7.0%) and those who did not. Differences were seen in the following: between study centres, weight gain during the run-in period and insulin therapy, and FPG during the last 12 weeks (5.7+/-0.2 vs 6.7+/-0.3 mmol/l for patients reaching vs those not reaching target, p<0.01). CONCLUSIONS/INTERPRETATION: Good glycaemic control can be achieved with both G+MET and NPH+MET. Use of G+MET reduces symptomatic hypoglycaemia during the first 12 weeks and dinner time hyperglycaemia compared with NPH+MET.

Role of apolipoproteins E and C in type V hyperlipoproteinemia.

Type V hyperlipoproteinemia is characterized by elevations of chylomicron (CM) and very low density lipoprotein (VLDL) triglycerides. The development of this lipid disorder involves a multitude of metabolic derangements including deficient clearance of triglycerides and/or their increased output aggravated by obesity, diabetes, alcohol intake, or use of some hormones. Some studies have suggested that the apolipoprotein E4 phenotype is involved in this dyslipoproteinemia but this concept is still a matter of controversy. Therefore, we determined the apoE phenotype in 21 patients with severe hypertriglyceridemia classified as type V. Their apoE4 gene frequency was 0.595 which is 2.6-fold higher (P less than 0.001) than that in the Finnish population. Correspondingly, their apoE3 gene frequency was lower than that in the normal population. No differences were noted in plasma lipoproteins of the apoE4 phenotypes and the other type V subjects. The apolipoprotein C-II and C-III distribution was similar to that in normolipidemic subjects. The results suggest that apoE4 may be involved in the development of type V hyperlipoproteinemia.

Novel polymorphism of the human ob gene promoter in lean and morbidly obese subjects.

OBJECTIVE: Leptin, the circulating product of the human ob gene, may play role in control of appetite and metabolic rate. We screened the proximal promoter area of the ob gene for mutations and common polymorphisms in order to find out whether genetic variation in the regulatory area of this gene plays a role in human obesity. DESIGN: The technique of single-strand-conformation polymorphism (SSCP) was applied to screen for the promoter area of the ob gene for genetic alterations in morbidly obese patients. SUBJECTS: A total of 249 morbidity obese (present or past body mass index [BMI] > or = 40 kg/m2) and 141 lean (BMI < or = 25 kg/m2) subjects. MEASUREMENTS: DNA analysis was carried out using a single-strand conformation polymorphism (SSCP) technique and PCR followed by digestion with the restriction enzyme BssHll. Leptin was determined by radioimmunoassay in obese subjects. Serum lipids, glucose and insulin concentrations in the obese subjects were also determined. RESULTS: A new polymorphism C(-188)A was identified in the promoter region of the ob gene. This polymorphism was detected with allelic frequencies of 0.06 in morbidly obese subjects and 0.09 in lean controls (P = 0.28). Initial studies failed to show an association of this polymorphism with serum leptin, response to treatment for obesity, history and extent of weight gain, or serum insulin, glucose of lipid concentrations. CONCLUSIONS: We have identified a common polymorphism in the promoter area of the human ob gene which appears to be very useful for genetic association and linkage studies. Further studies are needed to elucidate its potential role in the regulation of the human ob gene and in human metabolic disorders.

Contraceptives containing desogestrel or levonorgestrel have different effects on serum lipoproteins and post-heparin plasma lipase activities.

OBJECTIVE: We examined the effects of mono and polyphasic oral contraceptives containing desogestrel or levonorgestrel on serum lipoproteins, sex hormone binding globulin and post-heparin plasma lipase activities. DESIGN: The women took either desogestrel or levonorgestrel during the first menstrual cycle on days 15-28. They then received monophasic ethinyloestradiol plus either desogestrel or levonorgestrel for three cycles. After this, the women took sequential pills containing ethinyloestradiol plus either desogestrel or levonorgestrel for the three following cycles. Fasting blood samples were drawn pretreatment and at the end of each treatment. PATIENTS: The study group consisted of 30 apparently healthy women, aged 18-35. They were randomly divided into desogestrel and levonorgestrel groups, each consisting of 15 women. MEASUREMENTS: Cholesterol, triglyceride and phospholipids were determined in whole serum and in all lipoprotein fractions (following isolation of lipoproteins by ultracentrifugation). Plasma apolipoprotein A-I concentration, post-heparin plasma lipase activities and serum sex hormone binding globulin were also measured. RESULTS: Desogestrel (150 micrograms/day) did not change serum total triglyceride concentration, whereas levonorgestrel (150 micrograms/day) decreased it. Except for monophasic ethinyloestradiol plus levonorgestrel, the oestrogen-containing combinations increased serum triglyceride level. Low density lipoprotein (LDL) cholesterol remained stable with all treatments, but the cholesterol/triglyceride ratio of LDL decreased during all combinations with ethinyloestradiol. Levonorgestrel reduced total high density lipoprotein (HDL) cholesterol and both progestins reduced HDL2 cholesterol concentration. Addition of ethinyloestradiol reversed this change in the desogestrel but not in the levonorgestrel group. The polyphasic ethinyloestradiol plus levonorgestrel combination did not change total HDL cholesterol. Hepatic lipase was activated with either progestin when administered alone but its activity was suppressed below the baseline level when ethinyloestradiol was added. Conversely, both progestins suppressed sex hormone binding globulin levels, but addition of ethinyloestradiol caused marked increases above baseline. These increases were greater in women taking desogestrel than in those taking levonorgestrel. No treatment affected lipoprotein lipase activity significantly. CONCLUSIONS: Monophasic or polyphasic combinations of ethinyloestradiol and desogestrel do not have deleterious effects on serum lipoproteins. If levonorgestrel is used as the progestin component, polyphasic ethinyloestradiol plus levonorgestrel appears more favourable than monophasic ethinyloestradiol plus levonorgestrel.

A high prevalence of hypovitaminosis D in Finnish medical in- and outpatients.

OBJECTIVE: To study the prevalence of hypovitaminosis D [serum 25(OH)D < or = 37 nmol L-1)] in Finnish medical in- and outpatients in a cross-sectional study. METHODS: The subjects were 106 consecutive medical inpatients (57 females, 49 males with mean ages of 65 and 58 years) from the Peijas Hospital, Vantaa, Finland, and 99 ambulatory patients (48 females, 51 males with mean ages of 42 and 46 years) contacting a private outpatient centre in Helsinki, Finland. Serum 25(OH)D, vitamin D binding protein (DBP), free vitamin D index (FDI), intact PTH (iPTH), and albumin-corrected calcium were measured. RESULTS: Serum 25-hydroxyvitamin D [25(OH)D] was 37 nmol L(-1) or less in 70% of female and in 61% of male inpatients and in 44% of female and in 37% of male outpatients. In the whole population, a statistically significant inverse association (P < 0.0001) was detected between iPTH and 25(OH)D levels; the iPTH concentration appeared to start increasing when 25(OH)D concentration was 50 nmol L(-1) or less. The association remained the same (P < 0.0001) when FDI was used instead of 25(OH)D in the calculations. When the sexes were analysed separately, the statistically significant association was found only in females (P < 0.0001 for iPTH versus 25(OH)D; P < 0.0001 for iPTH versus FDI) but not in males. CONCLUSION: Hypovitaminosis D is very common amongst Finnish in- and outpatients in both sexes, causing secondary hyperparathyroidism in females. More extensive studies are warranted to elucidate the vitamin D status of the Finnish population.

Genetic polymorphism of platelet glycoprotein IIIa in patients with acute myocardial infarction and acute ischaemic stroke.

BACKGROUND: It has recently been suggested that the Leu33Pro polymorphism of the platelet glycoprotein IIIa affects the risk of coronary thrombosis. Finland is genetically isolated and has an incidence of cardiovascular disease among the highest in the world. Interestingly, the prevalence of ischaemic heart disease also varies in different parts of the country, being highest in eastern Finland. METHOD: We studied the Leu33Pro polymorphism using polymerase chain reaction in 133 patients with coronary artery disease, 234 patients with cerebrovascular disease and 326 control subjects originating from two areas of Finland. RESULTS: The frequencies of the Pro33 allele in the patients with acute myocardial infarction and cerebrovascular attack were 13% and 14%, respectively, and did not differ from the controls (13%). Among patients with acute myocardial infarction from the Helsinki area, the family history of premature coronary artery disease was more often positive in carriers of the Pro33 allele than in non-carriers, but after adjustment for multiple comparisons the difference was no longer significant. CONCLUSIONS: We could not confirm the original observation that the Pro33 allele constitutes an independent risk factor for coronary artery disease. Further studies are needed to clarify whether co-occurrence of Pro33 and some unrecognized inherited factor pose an additional risk of vascular disease.

Lack of association between the apolipoprotein B gene 3' hypervariable region alleles and coronary artery disease in Finnish patients with angiographically documented coronary artery disease.

Previous studies have suggested that some apolipoprotein B (apoB) 3' variable number of tandem repeats (3'VNTR) locus alleles are associated with coronary artery disease (CAD). We examined the possible association between the apoB 3'VNTR alleles and CAD in 387 Finnish subjects. Using the polymerase chain reaction and polyacrylamide gel electrophoresis, the 3'VNTR genotype was determined in 187 individuals with severe CAD confirmed by coronary angiography (patients), in 121 individuals with normal coronary angiograms (controls), and in 79 apparently healthy subjects (normals). In contrast to previous reports from other populations, the larger apoB 3'VNTR alleles were not significantly more frequent among CAD patients than among controls or normals. In addition, there was no significant association between the 3'VNTR alleles and serum lipid levels in this Finnish population.