[Evaluation of erythrocyte deformability in subjects with sickle cell trait during a soccer game: effect of hydration ad libitum]. / Évaluation de la déformabilité érythrocytaire des sujets porteurs de trait drépanocytaire au cours d'un match de football : effet de l'hydratation ad libitum.

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.

The vascular endothelium masks the persistent inhibition of rat thoracic arterial tone induced by S-nitrosoglutathione.

AIM: In endothelium-denuded arteries, the nitric oxide (NO) donor S-nitrosoglutathione (GSNO) induced a persistent hypo-reactivity to vasoconstrictors, and low-molecular weight thiols such as N-acetyl cysteine (NAC) produced a relaxant effect. These effects were attributed to the formation of vascular NO stores. In arteries with a functional endothelium, such long-lasting effects on arterial tone have not been well characterised. In this study, we proposed to examine the possibility of storing exogenous NO when the vascular endothelium is still able to produce its own NO. METHODS: For this purpose, changes in isometric tension of isolated arteries were assessed in organ chambers, and nitrosothiol formation was characterised by confocal microscopy. RESULTS: In rat aortic rings with endothelium pre-exposed to GSNO, the contractile response to norepinephrine (NE) was not attenuated in comparison with control rings, but NAC induced a relaxant effect. However, an attenuation of the response to NE was observed in GSNO-exposed, intact aortic rings after inhibition of NO synthase by N(ω)-nitro-L-arginine methylester (L-AME) or in GSNO-denuded rings. The relaxing effects of NAC were due to the mobilisation of NO from nitrosothiols after nitrosylation of protein SH residues. Moreover, the hypo-reactivity to NE and the relaxant effect of NAC were abolished by 1H-[1,2,4] oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase, and partially by the K+-sensitive channel inhibitor tetra-ethyl-ammonium (TEA). CONCLUSION: These data show that endothelium-derived NO masked the persistent effect of GSNO in rat thoracic aorta. However, the ability of GSNO to form releasable NO stores without altering the vascular tone can be particularly useful in preventing endothelial dysfunction in which NO formation decreases.

[Culture and characterization of porcine coronary endothelial cells]. / Culture et caractérisation des cellules endothéliales d'artère coronaire de porc.

INTRODUCTION: Vascular endothelium possesses biological properties that are involved in important physiological functions such vascular permeability, vascular tone regulation and angiogenesis. The difficulty of culture and long-term maintenance of sufficient amount of normal endothelial cells has proven to be the limitation for the understanding of the biological function of the endothelium. Therefore, the aim of this study was to culture and characterize the porcine coronary endothelial cells. MATERIAL AND METHODS: The endothelial cells were isolated by collagenase treatment and cultured in culture dishes coated with collagen, prepared from rat tail, containing medium RPMI1640/M199 and 15% fetal calf serum supplemented with antibiotics and fungizon. The cells were maintained to grown at 37 degrees C. The medium was changed one day after and then every two day. The cells were incubated with Dil-labeled-acetylated-LDL for determination of acetylated-LDL uptake. Confluence cultures of cells were examined by phase-contrast and confocal microscopy. RESULTS: After a day of culture, the endothelial cells adhere to the collagen and began to grow. While multiplying themselves, they colonize little by little the body of the surface of culture to form to confluence a monolayer of flat cells relatively homogenous. To confluence, the proliferation of the endothelial cells is inhibited by the contact and the cells present a polygonal aspect. Our results show that all the cultivated cells were strongly positive for acetylated-LDL markers. The endothelial cells, cultivated until the second passage corresponding to the second culture of the primary cultures, continued to present a good fluorescence. CONCLUSION: Porcine coronary endothelial cells represent a useful in vitro model to study biological and physiopathological properties of vascular endothelium.

[Physical performance and thermoregulatory study of subjects with sickle cell trait during a sub-maximal exercise]. / Etude de la performance physique et de la thermoregulation des sujets porteurs du trait drepanocytaire au cours d'un exercice sous maximal.

The sickle cell trait is a genetic abnormality of red blood cells. It is due to the mutation of a parental gene, which rest Its to the substitution of glutamic acid by valin on beta globin chain of haemoglobin. The possibility for sickle cell trait carriers (SCT) to present any disturbance during predominantly anaerobic and aerobic exercises is unclear. Ten (10) subjects with sickle cell trait and 10 subjects control were studied during exercise test on cycloergometer. They were all students of the National Institute of Popular Education and Sport of Dakar. The mean of environmental temperature was 26 degrees C and humidity was 60 to 80%. After haematological analysis, a submaximal muscular exercise for one hour with 75% of maximal heart rate was done. We have determined heart rate, blood pressure, rectal and skin temperature during exercise. Haematological parameters shown any significant difference between the two groups. No significant difference was found in cardiocirculatory variables during maximal exercise in cycloergometer between control group and sickle cell trait group. The two groups have done submaximal exercise during 1 hour without particular difficulty. We have not observed a significant difference between the two groups in cardiovascular variables, rectal and skin temperature during exercise, and after 3 minutes of rest. These results show that subjects with SCT have physical capacity comparable with control subjects during a sub maximal exercise for 1 hour. We can assure that subjects with SCT in our country may participate in sports competition, as well as normal subjects (HbAA).

[Comparative study of the effect of fasting during Ramadan on the glycaemia at rest in sportsmen and sedentaries]. / Etude comparative de l'effet du jeûne du ramadan sur la glycémie au repos chez des sportifs et des sédentaires.

The fast of Ramadan submits body to transient metabolic modifications; and decrease of glycaemia can be one of results. Physical exercise modifies rate of plasmatic hormones responsible for its regulation. The purpose of this study is to appreciate the influence of the fast on this biologic parameter in sportsmen and sedentaries. Thirty (30) healthy subjects (15 sportsmen of stamina and 15 sedentaries), with 25 years of average age were recruited. They have all a comparable diet. We excluded subjects having practised a physical exercise the day of the test. Capillary glycaemia was measured after weighed and physical exam, in 2 periods: in second Ramadan's fortnight, 15 minutes before food intake, two (2) months after Ramadan at least 4 hours at distance of the last meal. Comparisons were remitted in the test of Student, significant for p value lower than 0.05. During Ramadan, the glycaemia of the sportsmen at rest, is at one exception always superior or equal to that of the sedentaries. However, there is non significant difference as much during the fast as in normal food intake. Respective averages are 4.6 mmol/l, 0.15 and 4.5 mmol/l, 0.01 during Ramadan. They cross then in 4.8 mmol/l, 0.2 and 4.8 mmol/l, 0.4 in normal food intake. Landmark, the comparison of the averages from period to the other one in every group shows a significant difference only for the sedentaries. The return to normal food intake was expressed by an important gain in weight for all subjects. The fast of Ramadan has no notorious influence on sportsman's glycaemia contrary to that of sedentary. In other words, the sportsman administers better his stocks of glucose. Previous works however strongly advised against sports practice during Ramadan and more particularly the competitions, because, exercises of strong intensity can induce dehydration.

[Hepatitis B infection in infantile population of Sénégal]. / Etude de l'infection par le virus de l'hépatite B dans la population infantile au Sénégal.

Hepatitis B is endemic in Senegal. According to many data, the prevalence of this infection in adult population is up 85%. Young children are victims of the intensive circulation of this virus. Indeed, the risk of becoming chronic carrier which can further lead to Hepatocellular Carcinoma, is related to the age at which the infection had been contracted. In this study, we investigated the prevalence of HBV markers in children less than 5 years living in two regions of Senegal: Dakar and Thies. Using specific Elisa methods, HBV markers were determined in 2962 sera of newborns and children: AgHBs, antiHBc, antiHBs for all children; AgHBe and IgM antiHBc for AgHBs carriers. HBV markers were detected in 59.38% of sera; in 39.26% of the samples only one marker was detected: AgHBs (3.18%), antiHBc (36.08%), antiHBs (0.49%). In 20.12% of samples, markers were associated. So, the global prevalence of the infection is 59.38% with the predominance of chronic forms compared to acute one. The rate of chronic carriage is independent of the sex but is influenced by age and geographic area. The post- infection immunization rate is 7.11%. In Senegal Hepatitis B is contracted at the early childhood. The high prevalence of this infection in children under five years emphasize the need for a spread vaccination in this age bracket, since we well know that the risk for them to become chronic carriers is high.