Browsing by Author "Njogu, A. R."
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Item Monosaccharide composition of the surface glycoprotein antigens of Trypanosoma brucei(1974) Allsopp, B. A.; Njogu, A. R.; East African Trypanosomiasis Research Organization, Tororo, UgandaEvidence has been adduced that the surface antigens of Trypanosoma brucei subgroup are a group of glycoproteins having D-galactose, D-mannose and D-glucosamine as monosaccharide components. There was considerable variation in the number of antigen components, and their relative amounts, as revealed by isoelectric focusing on polyacrylamide gel. The relevance of these variations to the adaptation theory of antigenic variation in trypanosomes is discussed.Item Nature and Location of Trypanosoma bruce Subgroup Exoantigen and Its Relationship to 4S Antigen(1971) Allsopp, B. A.; Njogu, A. R.; Humphreys, K.C.; East African Trypanosomiasis Research Organisation, Tororo, UgandaIt has been suggested that exoantigen of Trypanosoma brucei subgroup is not continuously secreted by trypanosomes in the bloodstream of hosts. The antigen was not detected in plasma collected quickly, but appeared in increasing quantities when blood was removed from the host and allowed to stand. Analysis of exoantigen by isoelectric focusing in polyacrylamide gel has shown it to be a heterogeneous antigen of at least three components with a common antigenic determinant. Each of the components is a protein carbohydrate complex, having an isoelectric point (pI) in the pH range 6.0–5.5. Evidence was presented suggesting that this antigen is identical to 4S antigen, AND has its main location as a major component of the surface coat of bloodstream forms of T. brucei subgroup. The name “surface antigen” has been proposed, AND a method for rapidly preparing it in an apparently fairly pure form from trypanosomal homogenates has been detailed.Item Preliminary efficacy trial of Cymelarsan, a novel trypanocide, in camels naturally infected with Trypanosoma evansi in Kenya(1992) Otsyula, M.; Kamar, K.; Mutugi, M.; Njogu, A. R.; Kenya Trypanosomiasis Research InstituteThe novel trypanocide Cymelarsan (Mel Cy. RM11O; Rhone Merieux, France) was shown to have therapeutic activity against Trypanosoma evansi in naturally infected camels in Kenya, at dose rates ranging between 0.2 to 1.2 mg/kg body weight. Systemic and local reactions were mild and transient.Item Report on the Symposium on African Trypanosomiases(veterinary Record, 1986) Njogu, A. R.; Kenya Trypanosomiasis Research Institute,The ability of the African trypanosomes to vary their surface coats of glycoprotein antigens during infections of susceptible host animals has prevented the development of vaccines employing cell surface proteins, as is being attempted with other parasitic protozoa (see Cohen, 1986). Since the phenomenon of antigenic variation in protozoa was the subject of another symposium, of the five papers presented in this symposium one dealt with the possibility of sexual phenomena occurring in trypanosomes, one with the transmission of the organisms by tsetse to vertebrate hosts and one with the characteristics of the trypanosomes isolated from man. The fourth paper described the vertebrate host response to the parasites and the fifth described the control of such infections by chemotherapy.Item Trypanosomal antigen and antibody levels in field camels following treatment with two trypanocidal drugs(1992) Olaho-Mukani, W.; Munyua, W. K.; Njogu, A. R.; Mutugi, M. W.; Otsyula, M.; Kenya Trypanosomiasis Research InstituteThe efficacy of treatment in 61 naturally trypanosome- infected camels was evaluated by antigen and antibody detection. Following treatment of 14 infected field camels with an arsenical drug (RM ll0) no trypanosomal antigens could be detected in the animals which were treated with 0.6 mg/kg body weight and 1.2 mg/kg body weight, 90 days thereafter. In two out of three camels treated with 0.4 mg/kg body weight no trypanosomal antigens could be detected by day 90 post-treatment. However, there was evidence of trypanosomal antigens in camels treated with 0.2 mg/kg body weight and untreated positive controls. Antibody levels were still high in all the 14 camels, 90 days post-treatment. In another group of 55 field camels, of which 47 camels were parasite-positive and eight parasite-negative, trypanosomal antigens could not be detected in 42 camels, 28 and 48 days post-treatment with Quinapyramine Prosalt. However, antigen levels were still high in five parasite-positive camels, 48 days post-treatment. In all the parasite-positive camels, antibody levels were still high 48 days after treatment. In the eight parasite-negative camels, antigens were detected in four camels before treatment. By day 48 post-treatment, all the four camels were antigen-negative. However, four of the eight parasite-negative camels were still antibody-positive by day 48 post-treatment. These observations indicated that antigen-detection could be used to evaluate the success of therapeutic trials where trypanosome detection tests may fail to pick low patent infections.Item Trypanotolerance in East African Orma Boran cattle(veterinary Record, 1985) Njogu, A. R.; Dolan, R. B.; Wilson, A. J.; Sayer, P. D.Comparative studies on two types of large East African zebu (Bas indicus) Boran cattle, on a beef ranch in Kenya, have indicated that a Boran type bred by the Orma tribe has a superior response to tsetse fly challenge. The Orma Boran when compared with an improved Boran was found to have lower trypanosome infection rates and, when untreated, better control of anaemia and decreased mortality.
