Carvedilol does not modulate moderate exercise-induced hyperkalemia in hemodialysis patients

BACKGROUND AND AIM: Non-selective beta-adrenergic blockers may cause hyperkalemia in patients with end-stage renal failure. In contrast, alpha-adrenergic blockade has been found to decrease the hyperkalemic effect of physical exercise in healthy subjects, although we were unable to confirm this effect in hemodialysis patients. In a crossover design, we studied the effect of carvedilol, a non-selective beta-adrenergic blocker with an additional alpha1-blocking activity, on exercise-induced hyperkalemia in 17 anuric hemodialysis patients. METHODS: All subjects were given either carvedilol (25 mg/day) or placebo for 2 weeks in a random order with a 2-week wash-out period. At the end of each treatment period they underwent a 30-minute exercise test on a bicycle ergometer with a fixed load of 20 W. RESULTS: The treatment with carvedilol caused a significant decrease in blood pressure. Serum potassium before exercise tests was similar (5.37 +/- 0.2 and 5.24 +/- 0.2 mmol/l on carvedilol and placebo, respectively; mean +/- SE). During the exercise, serum potassium increased significantly (p < 0.001 in both tests) and subsequently decreased during 30 minutes of recovery (p < 0.05). The mean rate of potassium increment during the exercise was similar (23.3 +/- 3.3 micromol/l/min on carvedilol and 20.0 +/- 3.6 micromol/l/min on placebo). During recovery, the mean rate of potassium decrement was 5.0 +/- 3.0 micromol/l/min and 6.7 +/- 2.7 micromol/l/min, respectively. Serum sodium, ionized calcium, insulin and plasma renin activity were similar before the exercise tests and did not change during the exercise. CONCLUSION: Carvedilol does not enhance the hyperkalemic effect of moderate physical exercise in anuric hemodialysis patients.     

Severe and selective deficiency of interferon-gamma-producing invariant natural killer T cells in patients with myelodysplastic syndromes

Here we show that patients with myelodysplastic syndromes (MDS) have a severe deficiency of glycolipid reactive Valpha24+/Vbeta11+ natural killer T (NKT) cells, but not NK cells or CD4+ or CD8+ T cells. Neither the blood nor marrow of MDS patients had detectable interferon-gamma-producing NKT cells in response to the NKT ligand, alpha-galactosyl ceramide, although influenza-virus-specific effector T-cell function was preserved. This severe and selective deficiency of an important immune regulatory cell may contribute to the pathogenesis of MDS.     

Lipid profiles in Polish adolescents from high- and low-risk families: tracking unfavourable lipid levels over a one-year period

In a country with a high cardiovascular mortality rate, lipid profiles were studied in 929 adolescents (440 from affected and 489 from non-affected families for cardiovascular disease and hypercholesterolaemia). In 334 children with elevated or borderline total cholesterol level, lipid profiles were re-measured after a 1-y period. In boys from affected families, in contrast to boys from non-affected families, significantly higher total cholesterol levels (4.36 +/- 0.81 vs 4.19 +/- 0.78 mmol/L, p < 0.05) and LDL-C level (2.1 +/- 0.72 vs 1.89 +/- 0.79 mmol/L, p < 0.05) and significantly lower HDL-cholesterol levels (1.81 +/- 0.34 vs 1.93 +/- 0.38 mmol/L, p < 0.05) were found. The odds ratio for being in the most unfavourable decile for LDL-cholesterol was significantly higher for girls from affected families (2.17, p = 0.02). A relatively high HDL-C level as well as a favourable TC/HDL-C ratio was demonstrated in all groups, being lowest in boys from affected families. A significant correlation was found between baseline lipids and their values re-measured after 1 y. It is concluded that (1) adolescents with a positive family history are at increased risk for unfavourable lipid profile, (2) adolescents with elevated total cholesterol and LDL-cholesterol levels remain hypercholesterolaemic after a 1-y period and are therefore candidates for further biochemical and clinical monitoring, and (3) children with elevated total cholesterol may not be at high risk for cardiovascular disease owing to the favourable TC/HDL-C ratio. The study results do not indicate that general cholesterol screening in Polish adolescents is necessary, as the proportion of children with elevated LDL-cholesterol is relatively low.     

Anosmia caused by inhaled hazardous substances. Significance for expert assessment general practice

BACKGROUND: Both environmental and occupational pollutants can affect the functional integrity of the olfactory epithelium or even destroy olfactory tissue. However, occupational hyposmia and anosmia have not been included into the list of occupational diseases. Therefore, compensation of occupationally induced smell disorders is difficult. OBJECTIVE: To evaluate patients with toxic hyposmia for the pollutants involved and to discuss consequences for occupational and environmental medicine. METHODS: A total of 19 patients were evaluated in our departments between 1993 and 1997 for olfactory disorders related to environmental or occupational pollutants. The charts of these patients were retrospectically analyzed and the causative pollutants compared with the literature. RESULTS: A chronical exposure to mixtures of metal dusts and steam, volatile organic substances, and anorganic gases were the most common pollutants involved in occupational dysosmia. Only one case of acute development of an anosmia due to exposure to CO and combustion gases was documented. CONCLUSIONS: Olfactory disorders are underestimated in occupational and environmental medicine. Relevance of olfactotoxic substances for occupational medicine can be postulated in metal and chemical workers, in welding and disinfection. The list of occupational diseases should be completed by olfactory hyposmia and anosmia.     

Profile of families with parkinsonism-predominant spinocerebellar ataxia type 2 (SCA2).

Spinocerebellar ataxia type 2 (SCA2) has been recognized recently as an uncommon cause of parkinsonism, an alternate presentation to the typical cerebellar disorder. This research review summarizes the existing literature on parkinsonism-predominant presentation SCA2 and presents new clinical cases of patients with this condition. Various phenotypes are noted in this subtype of SCA2, including parkinsonism indistinguishable from idiopathic Parkinson's disease (PD), parkinsonism plus ataxia, motor neuron disease, and postural tremor. In several kindreds with multiple affected family members, the SCA2 expansion segregated with disease; in addition, several single cases of parkinsonism with and without a family history are also described. The number of repeats in symptomatic patients ranged from 33 to 43. Interruption of the CAG repeat with CAA, CGG, or CCG was found in some individuals, possibly stabilizing the repeat structure and accounting for the relative stability of the repeat size across generations in some families; allele length is not necessarily indicative of trinucleotide repeat architecture. Positron emission tomography scanning in one family showed reduced fluorodopa uptake and normal to increased raclopride binding with a rostrocaudal gradient similar to that found in idiopathic PD. This review emphasizes the importance of testing for SCA2 in patients with parkinsonism and a family history of neurodegenerative disorders. Testing for SCA2 is also important in studies of inherited parkinsonism.