Antiprotozoal effect of steroid hormone 20-hydroxyecdysone in giardiosis patients.

The World Health Organization reports that approximately 200 million people are infected with Giardia (G.) lamblia worldwide. Taking into account the emergence of resistance and the high toxicity of conventional drugs, research into new strategies to fight against G. lamblia is increasing. The aim of the study was to assess the antiprotozoal activity of 20-hydroxyecdysone in water sports athletes with giardiosis. A randomized, double-blinded, placebocontrolled clinical study was conducted. Seventy-six athletes with G. lamblia infection participated in the study and were divided into 20-hydroxyecdysone, metronidazole and placebo groups. Clinical, parasitological, haematological and biochemical analyses were performed. Positive results for antiprotozoal therapy were revealed in the 20-hydroxyecdysone and metronidazole groups. After therapy, elimination of G. lamblia was observed in 100.0% of the athletes included in the 20-hydroxyecdysone group. However, G. lamblia was resistant to metronidazole in 4.0% of athletes included in the metronidazole group. A positive clinical response to the therapy occurred in the 20-hydroxyecdysone and metronidazole groups. Our study reveals high antiprotozoal activity of 20-hydroxyecdysone against G. lamblia. Further clinical studies are necessary to evaluate the antiprotozoal efficacy of 20-hydroxyecdysone.

Association of the 25(OH) vitamin D status with upper respiratory tract infections morbidity in water sports elite athletes.

BACKGROUND: The aim of this study is to determine seasonal changes of total serum 25(OH) vitamin D (VD) concentration and its influence on upper respiratory tract infection (URTI) morbidity among water sports elite athletes. METHODS: The study was planned as a prospective, non-interventional, observational study. Study participants included 40 elite athletes and 30 control individuals. Serum levels of 25(OH) VD and TNF-α, IFN-γ, IL-4 and IL-6 were detected by ELISA technique. Frequency of acute URTI in participants was determined by medical cards and self-reported questionnaire during the year. RESULTS: VD deficiency/insufficiency dominated in both groups of elite athletes, especially in synchronized swimmers (100%) in comparison with the control individuals (63.3%) (P≤0.05). Prevalence of VD deficiency/insufficiency depends on the season, but independently on the season the highest values were observed among athletes. VD sufficiency was detected in 30% and 13.3% of the control individuals in August and February and only in 10% of swimmers in August. More than 3 episodes of URTI were detected only in elite athletes in winter-spring. The elevation of TNF-α, IL-4, IL-6 and decrease of IFN-γ levels were detected in all athletes, but they were more expressed in swimmers. CONCLUSIONS: VD insufficiency is quite pronounced among elite athletes engaged in synchronized swimming and swimmers. It is accompanied with a decrease of IFN-γ, increase of TNF-α, IL-4 and IL-6 level, and elevation of URTI morbidity. Seasonal monitoring and correction of the VD level for normalization of cytokine profile and decrease of URTI morbidity is definitely advised.

Dorsiflexor Muscle Oxygenation During Low, Moderate and Submaximal Sustained Isometric Contraction.

Sustained isometric contractions of skeletal muscles produce intramuscular pressures that lead to blood flow restriction. Thus, we have the paradox of rising O2 demand due to muscle activity and at the same time reduced blood flow. The aim was to assess muscle oxygenation during sustained isometric low (30%), moderate (60%) and submaximal [90% of maximal voluntary contraction (MVC)] contraction of the dorsiflexor muscle. Experiments were conducted on the dominant (right) leg of 8 male students (age 19 ± 2 years, weight 75 ± 6 kg). Tissue oxygen saturation (StO2) was recorded from the tibialis anterior using near-infrared spectroscopy. StO2 was higher at 30% compared to both 60% and 90% MVC at all time points after the start of the exercise and higher at 60% than 90%. This indicates that the supply of O2 did not keep up with its consumption. During arterial occlusion the minimal StO2 reached 52%, which is significantly higher than StO2 during 60% and 90% MVC. After each contraction there was a large and immediate hyperemic response, whose resaturation rate continuously increased from 30% to 60% to 90% MVC. The StO2 resaturation rate was positively correlated with the MVC, indicating a vasodilation depending on the intensity of the exercise.