Hormonal and metabolic adaptation in professional cyclists during training.

The aim of this study was to examine hormonal and metabolic changes in a group of 18 professional male cyclists ((.)VO(2)max 69.9 [95 % CI 64.9 to 74.9] mL x kg(-1) x min(-1) ) during two successive periods of adapted intensive training. The second training period included 4 days of cycling competition. Intensity was increased while volume was decreased in the second training. Anthropometric data were collected before and at the end of the two training periods. Venous blood samples were taken in a basal state before the two training sessions and after each training session. Serum concentrations of cortisol (C), testosterone (T), dehydroepiandrosterone sulfate (DHEAs), and catecholamines were determined as well as branched-chain amino acids (valine, leucine, isoleucine) (BCAA) and free fatty acids (FFAs). At the end of the two training periods, the subjects lost fat mass whereas mean body mass was unchanged. The T/C ratio was reduced transiently after the first training session (45.90 %), while DHEAs/C remained unchanged. T/C and DHEAs/C were significantly increased after the second training session compared to the first (48.40 and 97.18 %, respectively). Catecholamines and FFAs were unchanged. The significant increase in BCAA levels after the second training session was of note as it might constitute a "store shape" of amino acids in anticipation of future intense training loads. Based on the responses of testosterone, DHEAs, and cortisol, and on the training-induced increase in BCAA, there appeared to be hormonal and metabolic adaptation despite the inherent psychological stress of competition.     

Studies of novel variants associated with Hb F in Sardinians and Tanzanians in sickle cell disease patients from Cameroon

High level of Hb F has been shown to improve survival in sickle cell disease. Among 453 Cameroonians with sickle cell disease, we have investigated 18 selected single-nucleotide polymorphisms (SNPs) in novel and suggestive loci associated with Hb F level identified through a genomewide association study in sickle cell disease patients in Tanzania, and whole-genome sequencing of a population from Sardinia. Seven of 10 variants reported in Sardinians were either monomorphic or very rare in the Cameroonians. No associations were observed with any SNPs and Hb F levels in Cameroonians affected by sickle cell disease. The present study illustrates the complexity of replicating Hb F-promoting variants association results across populations.     

The spread of the Leu-Phe kdr mutation through Anopheles gambiae complex in Burkina Faso: genetic introgression and de novo phenomena

During extensive sampling in Burkina Faso and other African countries, the Leu-Phe mutation producing the kdr pyrethroid resistance phenotype was reported in both Anopheles gambiae ss and A. arabiensis. This mutation was widely distributed at high frequency in the molecular S form of A. gambiae while it has been observed at a very low frequency in both the molecular M form and A. arabiensis in Burkina Faso. While the mutation in the M form is inherited through an introgression from the S form, its occurrence is a new and independent mutation event in A. arabiensis. Three nucleotides in the upstream intron of the kdr mutation differentiated A. arabiensis from A. gambiae ss and these specific nucleotides were associated with kdr mutation in A. arabiensis. Ecological divergences which facilitated the spread of the kdr mutation within the complex of A. gambiae ss in West Africa, are discussed.     

Anemia in patients on chronic hemodialysis in Cameroon: prevalence,characteristics and management in low resources setting

BackgroundAnemia is a common complication of chronic kidney disease. We investigated the prevalence, characteristics and management of anemia in patients on chronic hemodialysis and assessed the response to blood-transfusion based management in Cameroon.MethodsThis was a cohort study of five months'' duration (August–December 2008) conducted at the Yaoundé General Hospital''s hemodialysis center, involving 95 patients (67 men, 70.5%) on chronic hemodialysis by a native arteriovenous fistula. A monthly evaluation included full blood counts, number of pints of red cell concentrates transfused, and vital status.ResultsAt baseline, 75 (79%) patients had anemia which was microcytic and hypochromic in 32 (43%). Anemia was corrected in 67 (70.5%) patients using blood transfusion only, while 28 (29.5%) patients were receiving erythropoietin (11 regularly, 39%). Only 77.2% of 342 pints (median 3.0, range 0–17 per patients) of red cell concentrates prescribed were effectively received during the follow-up at an unacceptably high cost to patients and families. Mean hemoglobin and mean corpuscular hemoglobin levels remained stable during follow-up, while mean corpuscular volume increased. Erythropoietin treatment was the main determinant of favorable trajectories of hematological markers.ConclusionsPatients on chronic hemodialysis have predominantly microcytic hypochromic anemia, with limited capacity for correction using blood transfusion.     

Molecular markers of Plasmodium falciparum drug resistance in southern highland Rwanda

In Rwanda, frequent mutations in the pfdhfr and pfdhps genes of Plasmodium falciparum have suggested intense sulfadoxine-pyrimethamine resistance. However, data on pfmdr1 are not available but might be important in the context of the first-line treatment with artemether-lumefantrine. During a survey among 749 children under five years of age in southern highland Rwanda, 104 P. falciparum isolates were obtained. Parasite polymorphisms associated with drug sensitivity were typed including the genes pfdhfr, pfdhps, pfmdr1, and pfcrt. Plasma concentrations of chloroquine and pyrimethamine were measured by ELISA. Treatment with artemether-lumefantrine within the preceding two weeks was stated by 12.5% of the respondents; chloroquine in plasma was detected in 17.6%, pyrimethamine in none. Isolates with pfdhfr triple and pfdhps double/triple mutations occurred in 75% and 93%, respectively; 69% of the isolates comprised pfdhfr/pfdhps quintuple or sextuple mutations associated with high-grade sulfadoxine-pyrimethamine resistance. Pfdhfr L164 was absent. The pfmdr1 pattern revealed more than 50% of the F184 polymorphism and almost 40% of the N86-F184-D1246 allele combination known to be selected in infections reappearing following artemether-lumefantrine treatment. Molecular markers demonstrate intense antifolate drug resistance of P. falciparum in southern Rwanda. The present, first-time data on pfmdr1 alleles from Rwanda reveal a pattern which might reflect a predominance of wild types for some alleles or, alternatively, substantial artemether-lumefantrine pressure on the local parasite population.     

Mildly elevated thyroid-stimulating hormone is associated with endothelial dysfunction and severe preeclampsia among pregnant women with insufficient iodine intake in Eastern Cape province,South Africa

BackgroundPreeclampsia and hypothyroidism are associated with endothelial dysfunction. Iodine deficiency is a risk factor for subclinical hypothyroidism in pregnancy. However, there is a paucity of data on the relationship between iodine nutrition state in pregnancy, the degree of endothelial dysfunction, and the risk of preeclampsia.MethodsNinety-five normotensive pregnant women, 50 women with preeclampsia with no severe features, and 50 women with severe preeclampsia were enrolled into the current study from the maternity units of Nelson Mandela Academic Hospital and Mthatha Regional Hospitals in Eastern Cape Province, South Africa. Urinary iodine concentration (UIC), serum markers of thyroid function, aortic augmentation index, and pulse wave velocity (PWV) were compared.ResultsMedian UIC was 167.5, 127.7, and 88.5 µg/L, respectively for normotensive pregnant women, those with preeclampsia and severe preeclampsia (p = .150). Participants with severe preeclampsia had significantly higher median thyroid-stimulating hormone (TSH) and oxidized LDL than normotensive and preeclamptic women without severe features (respectively 3.0, 2.3, and 2.3 IU/L; 1.2, 1.0, and 1.0 IU/L, p < .05). The median Aortic augmentation index was 7.5, 19.0, and 21.0 (p < .001), and the pulse wave velocity 5.1, 5.7, and 6.3, respectively for normotensive, preeclampsia, and severe preeclampsia participants (both p < .001). In linear regressions, TSH, age, and hypertensive disease were independent predictors of elevated PWV.ConclusionUpper normal-range TSH levels in women with severe preeclampsia were associated with markers of endothelial dysfunction. The low UIC and trend towards the elevation of thyroglobulin suggest that inadequate iodine intake may have increased TSH levels and indirectly caused endothelial dysfunction.