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J Coene

Publications and source records attributed to J Coene.

9 recordsLinked to original sources
PubMed1993

Gas chromatographic determination of alkyl lysophospholipids after solid-phase extraction from cell culture media.

The gas chromatographic determination of 1-O-octadecyl-2-O-methyl-DL-glycero-3-phosphorylcholine (Et-18-OMe), an anti-invasive alkyl lysophospholipid, in cell culture media is described. Sample clean-up was performed by solid-phase extraction on a weak cation-exchange column of the CBA type (carboxylic acid). For quantitation, the structural analogue Et-16-OMe as the internal standard was used after derivatization with trimethylsilyl bromide. The described method was free of interferences in cell culture media. The overall precision for twenty determinations was 14.99%.

Cells, Cultured↗
PubMed1993

Malaria in urban and rural Kinshasa: the entomological input.

Mosquitoes were collected on human bait over a 16-month period (September 1988 to December 1989) in an urban and a rural area of Kinshasa, Zaïre. P. falciparum malaria sporozoite rates were determined by ELISA. In the urban area Culex quinquefasciatus accounts for 96% of the 121 bites/person/night (b/p/n). The only anopheline is Anopheles gambiae, sensu stricto, with an average of 5.1 b/p/n and a sporozoite rate of 1.86%. The entomological inoculation rate (EIR) averages 0.08 infective b/p/n. Malaria transmission is almost interrupted at the end of the dry season. In the rural area mosquito nuisance is small (20 b/p/n), almost entirely due to six species of Anopheles including four vectors of malaria: An.gambiae (13.3 b/p/n), An.funestus (2.4 b/p/n), An.nili (0.4 b/p/n) and An.brunnipes (0.7 b/p/n) with mean sporozoite rates of 7.85%, 6.60%, 6.63% and 0.53% respectively. An.paludis (0.4 b/p/n) and An.hancocki (0.2 b/p/n) were not found infective. Malaria transmission is intense and perennial: the overall EIR varies monthly between 0.60 and 3.29 infective b/p/n. The specific contributions of An.gambiae, An.funestus and An.nili average 1.07, 0.14 and 0.03 infective b/p/n respectively. Malaria transmission peaks during the rainy season in both study areas. The daily mean survival rates for An.gambiae were 0.91 and 0.78 in the rural and urban area, respectively. All An.gambiae examined belonged to the forest cytotype (Coluzzi et al., 1979). Through its effect on the sporozoite rate, the higher vector survival rate in the rural environment appears to be the major determinant of the greater malaria transmission rate in the rural area as compared to urban Kinshasa.

Animals↗
PubMed1991

Comparison of the isolation of adducts of 2'-deoxycytidine and 2'-deoxyguanosine with phenylglycidyl ether by high-performance liquid chromatography on a reversed-phase column and a polystyrene-divinylbenzene column.

2'-Deoxycitidine (dCyd) and 2'-deoxyguanosine (dGuo) were subjected to reaction with phenylglycidyl ether (PGE) in methanol in order to study the formation of the corresponding 2'-deoxynucleoside adducts. Separation methods were developed on analytical and semi-preparative scales using high-performance liquid chromatography with photodiode-array detection on a reversed-phase column and on a polystyrene-divinylbenzene column. The use of the latter column was prompted by decomposition of the preparatively isolated dGuo-PGE adducts on the reversed-phase column. The use of a polystyrene-divinylbenzene column solved this problem and also revealed the presence of one more peak in both the dCyd- and dGuo-PGE reaction mixtures. The adducts of dCyd and dGuo were isolated on preparative reversed-phase and polystyrene-divinylbenzene columns and characterized by UV, fast atom bombardment mass and 360 MHz 1H NMR spectrometry. The adducts of dCyd were the diastereomers of N-3-(2-hydroxy-3-phenoxypropyl)-2'-deoxycytidine and N4-(2-hydroxy-3-phenoxypropyl)-2'-deoxycytidine whereas those of dGuo were the two diastereomers of N-7-(2-hydroxy-3-phenoxypropyl)-2'-deoxyguanosine and a third peak which appeared to be mainly N2-(2-hydroxy-3-phenoxypropyl)-2'-deoxyguanosine.

Chromatography, High Pressure Liquid↗
PubMed1991

Prospects for malaria control in urban and rural Kinshasa.

Malaria is a major cause of paediatric illness and death in Kinshasa, and all 3 million inhabitants are at risk. In view of the increasing chloroquine-resistance of Plasmodium falciparum, the early treatment of fever cases as the sole malaria control measure is no longer acceptable. The prospects for vector control are determined by the effectiveness, the acceptability and the practicability of the various methods in the local conditions of Kinshasa. Pronounced differences in the level of endemicity exist between the various parts of the town. These differences, and the ecological and socio-economic factors that underlie them, must be taken into account when estimating the potential of a control method. The reduction of man-vector contact through personal protection with impregnated bednets is the only realistic goal at this moment, but even a very marked decrease of the inoculation rate will produce little apparent effect in the highly endemic (semi-)rural districts at the periphery of town. In the urbanized center of Kinshasa, where the moderate to low intensity of transmission is more susceptible to a critical reduction, the same method may have an impact on malaria morbidity. Moreover, the big nuisance from non-vector mosquitoes in the urban area is an important motivating factor for the acceptance and the use of bednets. A mass effect, on the other hand, only is to be expected in isolated villages. Field trials are needed to evaluate the short- and long-term effect on malaria transmission and on its' clinical expression, as well as on the build-up of natural immunity, in the epidemiologically distinct areas. However, the final outcome of a large scale implementation of malaria control with impregnated mosquitonets will equally depend on health education, on the availability of bednets at low cost, on the creation of the appropriate structures for the (re)impregnation and distribution of the nets, and finally on the sustainability of the whole effort.

Democratic Republic of the Congo↗