Qualitative determination of carbon black in food products.

Carbon black (C.I. 77266) is an insoluble pigment produced by the partial combustion of hydrocarbons. The pigment is known by several synonyms, including vegetable carbon, lamp black and carbon ash, that correspond to the raw materials and methods used for its production. Vegetable carbon (E153) is permitted for use in colouring food in the European Union. The US Food and Drug Administration (USFDA) has not approved the use of any type of carbon black for colouring food, although the agency batch certifies the pigment as D&C Black No. 2 for use in colouring certain cosmetics. Since carbon black (as vegetable carbon) may be present in food products offered for import into the United States, the USFDA's district laboratories need a qualitative analytical method for determining its presence. We have developed an extraction method for this purpose. A sample is broken down and dissolved with nitric acid. The resulting solution is filtered and treated with hydrochloric acid to dissolve any black iron oxide also present as a colour additive. A black residue remaining on the filter paper indicates the presence of carbon black in the food. We confirmed the presence of carbon black in residues from several standards and food products using Raman spectroscopy. The limit of detection for this method is 0.0001%.

Changes in blindness prevalence over 16 years in Malawi: reduced prevalence but increased numbers of blind.

BACKGROUND/AIMS: In the coming two decades significant increases in the burden of blindness are anticipated unless concerted efforts are made to improve eye care in developing countries. Evidence of changing prevalence rates or numbers of blind people are few. The change in blindness prevalence and the number of blind people in an adult population of Malawi was measured over a 16 year period. METHODS: In 1999 a population based survey of blindness in adults (age 50+) was conducted in Chikwawa district of Malawi. Visual acuity and cause of vision loss were recorded for each eye independently. Blindness was defined as presenting better eye vision of <6/60. Findings from a 1983 survey of blindness in the same district (using similar methods) were re-analysed to be comparable with the survey conducted in 1999. RESULTS: Among 1630 enumerated adults 89% were examined. The age adjusted prevalence of blindness in the adult population was 5.4% and more common in women than men. In each age group the prevalence of blindness was lower in 1999 than in 1983; the overall reduction in blindness was 31%. During this period the 50+ population in Malawi increased almost twofold. Extrapolating the Chikwawa district data to the Malawi population reveals that the number of blind people has increased by 24%; the increase is primarily because of the large increase in the size of the most elderly group, aged 70 and above. CONCLUSION: The majority of blind people in Chikwawa (1983 and 1999) are in the age group 70 and over. This group has had the largest proportional increase in population size in this time. Services in this population have improved in the intervening 16 years and yet there was still an increase in the number of blind people. There was little change in excess blindness in women, suggesting that the same barriers that prevented utilisation of services in 1983 probably persist in 1999. Efforts to reach the most elderly and to reach women are needed to lead to a reduction in blind people in settings such as rural Malawi.

Reduction of trachoma in the absence of antibiotic treatment: evidence from a population-based survey in Malawi.

PURPOSE: A survey was conducted in Chikwawa District, Malawi in order to compare the current prevalence of trachoma with a similar survey in 1983. METHODS: Using random cluster household sampling, children aged 1 to 6 and adults aged 50 or older were enumerated and examined for the presence of trachoma. RESULTS: Among the 1313 children enumerated, 1249 (95.1%) were examined and among the 1431 adults enumerated, 1221 (85.3%) were examined. The prevalence of active trachoma among the children was 13.9% (11.9-15.9%), 10.0% in males and 14.4% in females. The prevalence of active trachoma varied significantly among the 25 clusters, ranging from 3.9% to 38.2% with 5 clusters (20%) having a prevalence >20%. Signs of trachomatous trichiasis were observed in 1.0% of adults examined. Active disease in 1999 was associated with a longer distance to the primary water source. CONCLUSIONS: Since 1983 there has been no mass antibiotic treatment programme in the district and little change in socioeconomic status. However, compared to the 1983 findings, active trachoma has been reduced by over 50% (p < 0.001) and trachomatous trichiasis by over 80%. In the 16-year interim (especially in the past 7 years) health, water and hygiene programmes were initiated and we hypothesize that the reduction in active disease is likely due to these changes. Our findings suggest that sustained reductions in active trachoma can be achieved without community-based antibiotic distribution.

The inducible prostaglandin biosynthetic enzyme, cyclooxygenase 2, is not mutated in patients with attenuated adenomatous polyposis coli.

Germ-line mutations in the APC gene cause adenomatous polyposis coli (APC), a syndrome in which patients develop hundreds to thousands of precancerous adenomatous colorectal polyps. We described previously an attenuated form of APC (AAPC) resulting from very 5' mutations in APC in which affected patients exhibit fewer colorectal polyps and a later age of onset of colorectal cancer. However, because striking variations in colorectal polyp numbers occur among patients carrying identical AAPC mutations, alleles of another gene may modify the expression of the APC disease phenotype. We tested the hypothesis that loss of function of human cyclooxygenase 2 (COX-2), known to modify the APC phenotype in the Apc delta716 mouse, results in a decreased tumor burden in AAPC patients that develop very few colorectal polyps. Genomic DNA sequence analysis of human COX-2 revealed a silent mutation in exon 3 that was evenly distributed between two classes of patients with AAPC, those with small or large numbers of colorectal polyps. We also found no difference in levels of COX-2 mRNA in transformed blood lymphocytes among AAPC patients of either class or patients with classical APC, and no alterations that correlated with a lesser or greater number of colorectal polyps were detectable within approximately the first 1 kb of the promoter sequence. Therefore, mutation of the human COX-2 gene does not appear to be responsible for a low tumor burden among AAPC subjects.

Vitamin A capsule supplementation in Malawi villages: missed opportunities and possible interventions.

A population-based survey was used to assess childhood and maternal vitamin A capsule coverage in Malawi and to investigate missed opportunities for capsule distribution. Overall, 9.3% of children had received vitamin A supplementation in the previous 6 months. Missed opportunities for receiving vitamin A were high in younger children. Fifty-five percent of mothers were covered in 8 villages served by volunteers and 23% in the 58 villages without volunteers. Existing strategies need to be redesigned and new strategies defined. For instance, mothers could receive supplementation during infant BCG vaccination, and children could receive initial supplementation during measles vaccination. Village health volunteers could be used to target children over 2 years of age.