Effects of root extracts of Fagara zanthoxyloides on the in vitro growth and stage distribution of Plasmodium falciparum

The development of resistance by Plasmodium falciparum to conventional drugs poses a threat to malaria control. There is therefore a need to find new, effective, and affordable remedies for malaria, including those derived from plants. This study demonstrates that crude, reverse-phase high-pressure liquid chromatography (RP-HPLC)-semipurified, and RP-HPLC-purified root extracts of Fagara zanthoxyloides inhibit the growth of P. falciparum in vitro, with 50% inhibitory concentrations (IC(50)s) of 4.90, 1.00, and 0.13 microg/ml, respectively. Roots of F. zanthoxyloides, known as chewing sticks, are widely used for tooth cleaning in West Africa. Microscopic examination of Giemsa-stained slides showed a virtual absence of schizonts in ring-stage synchronized cultures treated with crude extracts at concentrations of 30 to 60 microg/ml during 36 to 48 h of incubation. These observations suggest that the active constituent in the extract may be cytotoxic for P. falciparum trophozoites, thereby inhibiting their development to the schizont stage. A pure bioreactive fraction was subsequently obtained from the chromatographic separations. When this fraction was mixed with pure fagaronine, the mixture coeluted as a single peak on the analytical RP-HPLC column, suggesting that fagaronine may be the active antimalarial constituent of Fagara root extracts. Additional experiments showed that fagaronine also inhibited P. falciparum growth, with an IC(50) of 0.018 microg/ml. The results of this study suggest that the antimalarial activity of fagaronine deserves further investigation.     

Periodontal health status of school children in St. Vincent and the Grenadines.

A national oral health survey of school children was conducted in October through November 1991. The objective was to determine the periodontal status of school children in St. Vincent and The Grenadines (SVG), the pattern and severity of periodontal disease, estimate treatment needs and provide information for health planners. The study had a cross-sectional design, and 1646 schoolchildren representing all school districts were selected via multistage, systematic sampling. Examinations were conducted by three examiners using CPITN probe. Periodontal indicators and treatment needs were determined using the CPITN index. Calculus was the most prevalent condition with values ranging from 26 to 83 percent, bleeding was the least prevalent condition, while children with healthy indicator were intermediate in prevalence. Subjects with healthy indicators ranged from a low of 12 percent among 15-19 year olds, to a high of 51 percent among seven-year-olds. The mean number of healthy sextants varied from three to five, and mean number of sextants with bleeding or calculus varied from one to three. Oral hygiene instruction (OHI) was the most common treatment need, ranging from 49 to 88 percent. The need for prophylaxis was associated with increase in age, with the highest prophylaxis treatment needs of 83 percent, among 15-19 year olds. No significant differences were observed in periodontal status between gender, and also between urban and rural children. A high prevalence of calculus and bleeding was observed among SVG school children. Study recommends initiation of primary prevention programs in form of health promotion and health education.     

Correlates of myocardial oxygen demand measured by positron emission tomography in the hypertrophied left ventricle

BACKGROUND: The aim of this study was to identify the best correlate of myocardial oxygen demand (MVO(2)) in patients with hypertension induced left ventricular hypertrophy (LVH), and to examine whether relationships between these surrogates and MVO(2) differed between patients with LVH and control subjects. METHODS: We measured MVO(2) by positron emission tomography using carbon-11 acetate in 20 patients and 10 normotensive control subjects, and compared the relationships between commonly used surrogates and MVO(2). RESULTS: With the exception of diastolic blood pressure, the same variables correlated with resting MVO(2) in the patients and control subjects. CONCLUSIONS: The best correlate of resting MVO(2) in the patients with hypertension induced LVH was the stress-mass-heart rate product.     

Status of forest onchocerciasis in the Lower Cross River basin, Nigeria: entomologic profile after five years of ivermectin intervention

In the Lower Cross River basin in Nigeria, no pre-control entomologic profile of Onchocerca volvulus infection in the local Simulium damnosum population was available prior to the initiation of an ivermectin control program in 1995. A longitudinal entomologic study was therefore carried out over a 12-month period (January-December 2001) at the Agbokim waterfalls and Afi River, which are breeding sites of S. damnosum in the river basin. A total of 9,287 adult S. damnosum were caught on human bait; 9,048 (97.43%) were dissected, of which 313 (3.46%) were infected. Annual biting rates (ABRs) of 42,419 and 28,346 bites per persons per year were recorded at the Agbokim Waterfalls and Afi River, respectively. The annual transmission potential (ATP) was 419 infective larvae per person per year at the Agbokim Waterfalls and 427 at the Afi River. Monthly biting rate and monthly transmission potential varied significantly (P < 0.05) at the two sites. Transmission was highly seasonal from April to September, corresponding to the peak biting period of the vector. The high ATP and ABR values are a measure of the mesoendemicity of onchocerciasis in the river basin. There was a significant F(0).05 (1, 10) (P < 0.05) variation in the relative fly abundance from both sites. It was observed that human activities such as farming, fishing, timber cutting, and hunting are done in the early morning and late afternoon, which corresponds to the peak diurnal biting period of the vector. Changes in these practices and attitudes may markedly affect the disease intensity and transmission.     

Novel colorimetric assay of indomethacin using 4-carboxyl-2,6-dinitrobenzene diazonium ion

A simple, sensitive and direct colorimetric method for the determination of indomethacin either in pure form or in capsules has been developed. The method is based on the diazo coupling reaction between indomethacin and a highly reactive arenediazonium ion, 4-carboxyl-2,6-dinitrobenzene diazonium ion, with the consequent formation of an azo dye. The reaction is fast and gave an orange azo dye in ethyl acetate. The assay was carried out at 470 nm and the azo adduct was stable for three hours. Beer's law is obeyed in the concentration range of 3.3-11 microg mL(-1) of indomethacin. Optimization studies established an optimum reaction time of 20 minutes at 30 degrees C and the drug-to-reagent ratio of 1:2 for optimal detector response. The method developed has a low limit of detection of 0.90 microg mL(-1) and is precise (RSD 2.3%). The new method has been successfully applied to the determination of indomethacin in capsules and the method is of equivalent accuracy as the official (BP) spectrophotometric method. The new method could find application as a simple analytical method for the assay of indomethacin in capsules.     

The epidemiology of Entamoeba histolytica in a Nigerian urban population.

Microscopic examination of multiple faeces samples of 2 825 persons was carried out in the Metropolitan Lagos. Overall prevalence of Entamoeba histolytica was 11.2%. Prevalence increased rapidly in younger age groups and there were no real differences between males and females. Prevalence was high among families who ate together from the same plate, among those who ate with their fingers and among those who ate away from home. Prevalence was not associated with type of water supply but was seemingly influenced by storage of household supplies. A low infection rate was associated with the availability of water closets and toilet habit. No association was found between prevalence and standard of education but the rate of infection was increased among workers with high occupational interaction. Significant differences were found among different ethnic groups. The highest infection rate was recorded in the last month of the wet season.     

Smokeless tobacco-induced lamellar body abnormalities

OBJECTIVES: To compare the morphological changes and quantitative distribution of lamellar bodies (Lb) (membrane coating granules) in the hamster cheek pouch epithelium with smokeless tobacco (ST). MATERIALS AND METHODS: Archives of experimental material from previously published studies [S. Ashrafi, A. Das, R. Worawongvasu, B. Mehdinejad and J. Waterhouse (1992) Scanning Microscopy6: 183] were utilized. Animals in experimental group received most ST (snuff) in their right pouch, 5 days weekly, for 24 months, while no snuff was given to control group. After 24 months, the epithelial tissues were processed for electron microscopic study. Volume densities of Lb were assessed by morphometry. MAIN OUTCOME MEASURES: Densities of Lb in the two groups, experimental vs control. RESULTS: In the control, Lb extruded their contents into the intercellular spaces of upper granular layers and in between the last granular cell layers and keratin layers to form a permeability barrier. Conversely, in the smokeless tobacco-treated epithelium, the majority of the Lb that were formed remained inside and accumulated within the granular cells, without extruding their contents into the intercellular spaces to form a lipid compound permeability barrier. CONCLUSIONS: Commercial alkaline ST may have contributed to the abnormal accumulation of Lb in the granular cell layer and affected the extrusion process of Lb to form an incomplete permeability barrier in the oral epithelium.