The blood antioxidant defence capacity during intermittent hypoxic training in elite swimmers

The main objective of this study was to examine the chronic effect of simulated intermittent normobaric hypoxia on blood antioxidant defence capacity in swimmers. The study included 14 male and 14 female competitive swimmers performing part of land training under simulated intermittent normobaric hypoxia (O₂ = 15.5%) or in normoxia. Land interval training took place twice per week, with a total of 8 training units during the study, performed with individualized intensity. The activities of blood antioxidant enzymes did not change significantly during the first and last training unit in the hypoxic and normoxic group. However, when comparing individual variables a significant effect of exercise was observed on GPx an CAT activities, whereas training units significantly differentiated GPx and GR activities. The oxygen conditions and gender had a significant influence on CAT activity. The total antioxidant capacity was not significantly affected. Only in male swimmers from the hypoxic group did the training significantly increase resting levels of MDA. In conclusion, training in normobaric hypoxia was not an adequate stimulus for the excessive response of the antioxidant defence system, despite increased oxidative stress in these conditions.

Prediction of retention times of peptide nucleic acids during reversed-phase high-performance liquid chromatography

Peptide nucleic acids (PNAs) are synthetic biopolymers consisting of nucleobase side chains attached to an amino ethyl glycine backbone. At present this family of compounds enjoys a well deserved popularity in biomedical research, due to a number of favorable biological and chemical properties of PNAs compared to conventional oligonucleotides. PNAs are basically peptides, and are synthesized, purified and analyzed by traditional peptide chemistry, chromatography and mass spectrometry techniques. In the current report, we analyzed factors that influence the elution behavior of 29 PNAs on reversed-phase high-performance liquid chromatography using a water-acetonitrile-trifluoroacetic acid gradient elution system on C18 columns. We found that increasing the temperature from 25 degrees C to 55 degrees C resulted in improved peak shape and resolution. The retention times of the PNA analogs were dependent upon the length of the polymers with longer PNAs eluting later. Mixtures of PNAs with length, originating from inefficient monomer coupling during the polymer assembly, could be separated by single chromatographic runs. The retention time also depended upon the cytosine, thymine, adenine and guanine contact of the polymers. These differences in the contribution to the retention times could be explained by simple hydrophobicity features of the monomer side chains at pH 1.8. Based on all data, a linear equation was generated which predicted the retention time of any synthetic PNA based on composition and length. Comparison of the predicted and observed retention times showed a remarkable reliability of the algorithm.

Ataxia with isolated vitamin E deficiency in four siblings

We describe 4 siblings of a consanguineous Bedouin family with Friedreich ataxia phenotype in whom low serum vitamin E levels without other indicators of fat malabsorption were detected. Although age of onset and some of the clinical features were alike in all 4 patients, the electrophysiological parameters were markedly abnormal in 2, but normal in the other 2. Erythrocytes revealed both membranous and intracellular evidence of oxidative damage. The mutations described in other families with ataxia with isolated vitamin E deficiency were not detectable, nor was an abnormal single-stranded conformation polymorphism pattern apparent in the three exons at the 3' region of the gene. Vitamin E administration in pharmacological doses improved the neurological condition in 2 patients and also corrected some of the patients' erythrocyte cell abnormalities. The finding of vitamin E deficiency in other cases of Friedreich ataxia phenotype may allow treatment at an early stage of the disease, when large dose Vitamin E therapy may reverse the neurological lesions.

The association of obesity with joint pain and osteoarthritis in the HANES data

Data from 4225 persons from the National Health and Nutrition Examination Survey (HANES) was used to determine whether obesity was associated with osteoarthritis (OA) or joint pain. Subjects were divided into four groups on the basis of sex and race. We found that obesity was associated with OA of the knee for each sex/race group (p less than 0.01). The association was strongest for women, and it was present even for subjects without evidence of knee pain on physical examination. Frame size was not significantly associated with OA of the knee. Relative weight was weakly associated with OA of the hips in white women and nonwhite men but not significantly associated with OA of the sacroiliac joint. Diabetes did not seem to be an important risk factor for OA. These results suggest that the additional mechanical stress resulting from obesity is the principal reason for the association between obesity and OA.