Prevalence of traditional cardiovascular risk factors among Nigerians with stroke.

UNLABELLED: Stroke is an important cause of morbidity and mortality worldwide. The case fatality rates from stroke are two- to three-fold higher in sub-Saharan Africa, including Nigeria, than in the developed world, mainly because of limited healthcare facilities and untreated risk factors. The aim was to determine the prevalence of traditional cardiovascular risk factors among Nigerians with stroke and compare the prevalence of risk factors between young and older adults with stroke. METHODS: The study was cross-sectional in design, and was carried out on stroke patients who were 15 years of age or older, in the medical wards and neurology clinic of Aminu Kano Teaching Hospital, Nigeria. Data was collated consecutively over six months. RESULTS: A total of 81 patients were studied. Sixteen of them (19.8%) were under 45 years old (group 1) while the remaining 65 patients (80.2%) were 45 years or older (group 2). All patients had at least one risk factor. One-third of group 1 patients (37.5%) and 81.5% of group 2 patients had three or more cardiovascular risk factors (p = 0.0004). The most widespread risk factor in all patients, particularly in group 2 patients was systemic hypertension, while dyslipidaemia was most common among group 1 patients. Recurrent stroke was significantly more common among group 2 than group 1 patients (30.8 and 6.3% respectively) (p = 0.045). CONCLUSION: Cardiovascular risk factors, particularly hypertension and dyslipidaemia were prevalent in the studied patients with stroke. The older patients in group 2 had more multiple-risk factors than the younger ones in group 1. Secondary prevention strategies including detection and treatment of risk factors may curtail the burden of the disease.

Properties of a blood-meal-induced midgut lectin from the tsetse fly Glossina morsitans.

The properties of a blood-meal-induced lectin (agglutinin) from the midgut of Glossina morsitans capable of agglutinating Trypanosoma brucei were studied in vitro. The midgut homogenate from flies that had been fed twice had the highest agglutination activity, followed by that from the once-fed flies and that from the unfed insects. As compared with the bloodstream-form trypanosomes, a much lower concentration of the midgut homogenate was required for agglutination of the procyclic parasites. Furthermore, the agglutination process was specifically inhibited by D-glucosamine. Soybean trypsin inhibitor abrogated agglutination of the bloodstream-form parasites, whereas the procyclics were unaffected. The agglutination process was temperature-sensitive, with little activity being evident between 4 degrees and 15 degrees C. Similarly, heating the midguts to 60 degrees-100 degrees C led to loss of activity. When the midgut homogenate was separated by anion-exchange chromatography, the agglutination activity co-eluted with trypsin activity at approximately 50% NaCl. These results suggest a very close relationship between midgut trypsin-like enzyme and the agglutinin. Since successful agglutination of bloodstream-form trypanosomes requires protease activity, it may be that the enzyme cleaves off some surface molecules on the parasite surface, thus exposing the lectin-binding sites.

Purification and characterization of a midgut lectin-trypsin complex from the tsetse fly Glossina longipennis.

A blood-meal-induced lectin (agglutinin) with proteolytic activity was isolated from midgut extracts of Glossina longipennis by a two-step procedure involving anion-exchange chromatography. It is a glycoprotein [native molecular weight (M(r) 61,000 +/- 3000 da) composed of two noncovalently-linked subunits designated alpha (M(r), approximately 27,000 da) and beta (M(r), approximately 33,000 da). The trypsin activity and the glycosyl residues were present on the alpha- and beta-subunits, respectively. The native protein was capable of agglutinating both bloodstream-form and procyclic trypanosomes as well as rabbit red blood cells. This activity was strongly inhibited by D-glucosamine and weakly inhibited by N-acetyl-D-glucosamine. Similarly, soybean trypsin inhibitor abrogated agglutination of bloodstream-form parasites, whereas the procyclics were unaffected. The agglutination activity was sensitive to temperatures above 40 degrees C but was unaffected by chelators of metal ions. Antibodies raised against the protein were used in immunoblotting experiments to show the presence of a similar protein in several members of the Glossina species. However, no cross-reactivity was detected with midgut extracts prepared from sandflies, mosquitoes, or stable flies. It is proposed that this molecule might play an important role in differentiation of bloodstream-form trypanosomes into procyclic (midgut) forms.