Abdoulaye Samb

Lipids and fatty acids in muscle, liver and skin of three edible fish from the Senegalese coast: Sardinella maderensis, Sardinella aurita and Cephalopholis taeniops

Lipid content and fatty acid composition were determined in three species of edible fish caught in Senegalese waters during the upwelling season (January, 1993). Sardinella maderensis and Sardinella aurita are fat fish containing more than 5% (fresh wt.) of lipids, whereas Cephalopholis taeniops is a lean fish with approximately 1% of lipids. Skin, liver and muscle were studied for each fish species. About 40 fatty acids were identified by GC and GC/MS as methyl esters and N-acyl pyrrolidides. Palmitic acid was the main acid in the muscle and skin of all samples studied (20-33% of total fatty acids). Oleic acid was the main fatty acid in the liver of S. maderensis (27.2%+/-0.1) and S. aurita (44.7%+/-0.1). Arachidonic acid was a minor component in all samples. The flesh (muscle) of the three fish species contained high concentrations of omega3 polyunsaturated fatty acids (PUFA), ranging from 16.0 to 29.1% and including 20:5 omega3 (eicosapentaenoic acid, EPA) and 22:6 omega3 (docosahexaenoic acid, DHA) acids as major components. These two acids together accounted for 24.7%+/-0.1 and 12.9%+/-0.1 of total acids in the skin of S. maderensis and S. aurita, respectively. The percentages of PUFA found in the fish studied were very similar to those in fish used commercially as sources of PUFA. Muscle sterols, which accounted for 9-11% of total lipids, consisted mainly of cholesterol (up to 97% of total sterols).

Effects of hydration and dehydration on blood rheology in sickle cell trait carriers during exercise

This study compared the hemorheological responses of a group of sickle cell trait (SCT) carriers with those of a control (Cont) group in response to 40 min of submaximal exercise (exercise intensity, 55% aerobic peak power) performed in two conditions: one with water offered ad libitum, i.e., the hydration (Hyd) condition, and one without water, i.e., the dehydration (Dehyd) condition. Blood and plasma viscosities, as well as red blood cell rigidity, were determined at rest, at the end of exercise, and at 2 h recovery with a cone plate viscometer at high shear rate and 37 degrees C. The SCT and Cont groups lost 1 +/- 0.7 and 1.6 +/- 0.6 kg of body weight, respectively, in the Dehyd condition, indicating a significant effect of water deprivation compared with the Hyd condition, in which body weight remained unchanged. Plasma viscosity increased with exercise and returned to baseline during recovery independently of the group and condition. As previously demonstrated, resting blood viscosity was greater in the SCT carriers than in the Cont group. Blood viscosity increased by the end of exercise and returned to baseline at 2 h recovery in the Cont group in both conditions. The blood viscosity of SCT carriers did not change in response to exercise in the Dehyd condition and remained elevated at 2 h recovery. This extended hyperviscosity, in association with other biological changes induced by exercise, could be considered as a risk factor for exercise-related events in SCT carriers, similar to vasoocclusive crises, notably during the recovery. In contrast, the Hyd condition normalized the hyperviscosity and red blood cell rigidity of the SCT carriers, with blood viscosity values reaching the same lower values as those found in the Cont group during the recovery. Adequate hydration of SCT carriers should be strongly promoted to reduce the clinical risk associated with potential hyperviscosity complications.

Mild haemorheological changes induced by a moderate endurance exercise in patients with sickle cell anaemia

The levels and duration of physical activity that can be considered as completely safe in patients with sickle cell anaemia (SCA) is unknown. The present study compared the haemorheological and haematological profile, cell density distribution and basic biochemistry between a group of 17 patients with SCA and 21 healthy subjects before and after a 20 min duration submaximal cycling exercise at the same absolute workload. Blood was sampled at rest and 3 min after the end of exercise for measurement of biological parameters. Exercise did not affect the haematocrit and blood viscosity in the two groups. Plasma viscosity was not different between the two groups at rest and similarly increased with exercise. The proportion of intermediary dense cells (with density between 1·11 and 1·12 g/ml) decreased with exercise in the SCA group resulting in an increase in the proportion of red blood cells with a density >1·12 g/ml. No change was observed in the control group. The present study suggests that mild‐moderate exercise is not very harmful for SCA patients. The haemorheological and haematological changes were very mild, except for the formation of dense cells but no clinically significant signs of medical complication were present in any of the patients.

FATTY ACID COMPOSITION OF TWELVE SPECIES OF CHLOROPHYCEAE FROM THE SENEGALESE COAST

Abstract Twelve macroscopic algal species belonging to three orders of Chlorophyceae from the Senegalese coast were investigated for their fatty acid content by capillary GC. Our results, as well as other published data, show that fatty acid composition offers discriminant features for the chemotaxonomic classification of this algal class. High contents of 16:3ω3 distinguish the Siphonales from the Ulotrichales and the Cladophorales which are rich in 16:4ω3. A ratio of cis -vaccenic to oleic acid higher than one and the presence of large amounts of 18:4ω3 distinguish the Ulotrichales from the Cladophorales.

Sterol composition of twelve chlorophyceae from the senegalese coast and their chemotaxonomic significance

Abstract Twelve macroscopic marine algae belonging to three Chlorophyceae orders were investigated for their sterol composition by capillary GC. Our results, as well as literature data, show that sterol composition offers distinguishing features for the chemotaxonomic classification of these algae. Isofucosterol is typical for Ulotrichales and clionasterol for all species of Siphonales not belonging to Codium genus which is, itself, characterized by clerosterol. Cladophorales seem not to possess a representative sterol profile.

New branched-chain fatty acids from the senegalese gorgonianLeptogorgia piccola (white and yellow morphs)

Fatty acids from total lipids of the gorgonianLeptogorgia piccola (white and yellow morphs), collected from the same area at two different periods with regard to the average water temperature, were studied. More than fifty fatty acids were identified as methyl esters andN-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry. Three new, branched-chain unsaturated fatty acids were identified in addition to the unusual 7-methyl-6-hexadecenoic acid, namely 10-methyl-6-hexadecenoic, 7,9-dimethyl-6-hexadecenoic, and 10-methyl-6,9-heptadecadienoic acids. Also 6,9-heptadecadienoic acid was identified. The fatty acid patterns of specimens harvested in colder waters were quite different from those harvested in warmer waters in that the former contained high amounts of methylene-interrupted polyunsaturated acids, including tetracosapolyenoic acids, especially 6,9,12,15,18–24∶5 (up to 15.8% of the total acid mixture) and 6,9,12,15,18,21–24∶6 (up to 5.3%). Arachidonic acid was, nevertheless, a major component in all the fatty acid mixtures studied (13.6–20.5%). Based on gas chromatography/Fourier transform infrared experiments, the double bonds were assigned the (Z) configuration. Several fatty aldehydes and their dimethyl acetals were also detected, of which the most abundant was octadecanal.

Polysiphenol, a new brominated 9,10-dihydrophenanthrene from the senegalese red alga polysyphonia ferulacea

Polysiphenol (3), the first metabolite with a 9,10-dihydrophenanthrene skeleton isolated from marine source, was isolated from the Senegalese red alga Polysiphonia ferulacea. Its structure, including absolute configuration, was determined by spectroscopic data, and its conformation studied by molecular mechanics.

An unusual ether glycolipid from the Senegalese sponge Trikentrion loeve Carter

Abstract A unique ether glycolipid, 1 , characterized by the glycosylation of two glycerol hydroxy groups, has been isolated from the Senegalese sponge Trikentrion loeve Carter, and its structure determined by spectroscopic and chemical analysis.

Exercise-related complications in sickle cell trait

This review presents the epidemiological data regarding the exercise-related complication in exercising sickle cell trait carriers, and focuses on the different potential mechanisms that could be involved in these adverse events, such as hemorheological alterations, inflammation, vascular adhesion of circulating blood cells, oxidative stress and impaired nitric oxide metabolism. We also discuss the effects of different modulating factors such as vascular function, environment (hot temperature), hydration status, physical fitness, exercise intensity and genetic factors.

Effects of hydration and water deprivation on blood viscosity during a soccer game in sickle cell trait carriers

The present study compared the changes in blood viscosity, hydration status, body temperature and heart rate between a group of sickle cell trait (SCT) carriers and a control (Cont) group before and after a soccer game performed in two conditions: one with water offered ad libitum (hydration condition; Hyd) and the other one without water (dehydration condition; Dehyd). Blood viscosity and haematocrit per blood viscosity ratio (HVR; an index of red blood cell oxygen transport effectiveness) were measured before and at the end of each game. Resting blood viscosity was greater in the SCT carriers than in the Cont group. The increase of blood viscosity over baseline at the end of the game in the Cont group was similar in the two conditions. In contrast, the change in blood viscosity occurring in SCT carriers during soccer games was dependant on the experimental condition: (1) in Dehyd condition, blood viscosity rose over baseline; (2) in Hyd condition, blood viscosity decreased below resting level reaching Cont values. The Cont group had higher HVR than SCT carriers at rest. HVR remained unchanged in the Cont group at the end of the games, whatever the experimental condition. Although HVR of SCT carriers decreased below baseline at the end of the game performed in Dehyd condition, it increased over resting level in Hyd condition reaching the values of the Cont group. Our study demonstrated that ad libitum hydration in exercising SCT carriers normalises the blood hyperviscosity.