Codon usage patterns in chromosomal and retrotransposon genes of the mosquito Anopheles gambiae

Codon usage was compiled for fourteen chromosomal genes and four retrotransposons from the mosquito Anopheles gambiae. Variation exists among chromosomal genes in the degree of bias. The genes showing the highest bias are probably most highly expressed. In these genes, the base composition at the third codon position is much richer in G + C than is the overall coding sequence. Thus, codon usage is biased toward G- or C-ending codons. Codon usage in each retrotransposon is quite different, not only from chromosomal genes but also from the other retrotransposons. Codon usage comparisons among homologous genes from An. gambiae and two other Dipterans, the yellow fever mosquito Aedes aegypti and the fruitfly Drosophila melanogaster, show that while there are similarities, particularly between An. gambiae and D. melanogaster in the preference for G-and C-ending codons, each species has evolved a distinct pattern of codon usage.     

Using clinical signs to diagnose anaemia in African children.

Anaemia is a serious and common problem among young children in sub-Saharan Africa. As a first step towards developing guidelines for its recognition and treatment, we conducted a study to evaluate the ability of health workers to use clinical findings to identify children with anaemia. Health care workers examined a total of 1104 children under 5 years of age at two hospital-based outpatient clinics in rural Malawi. Blood samples were taken to determine haemoglobin concentrations. Pallor of the conjunctiva, tongue, palm or nail beds was 66% sensitive and 68% specific in distinguishing children with moderate a anaemia (haemoglobin concentration, 5-8 g/dl) and 93% sensitive and 57% specific in distinguishing those with severe anaemia (haemoglobin concentration, < 5 g/dl). Even without laboratory support, which is often unavailable in rural Africa, clinical findings can identify the majority of children with anaemia.     

Breast and cervical cancer surveillance, United States, 1973-1987.

Breast and cervical cancer incidence and mortality rates were reviewed for the period 1973-1987. For breast cancer, mortality has been relatively stable, increasing from 26.9/100,000 women in 1973 to 27.1 in 1987. Alternatively, data from the National Cancer Institute's Surveillance, Epidemiology, End Results Program (SEER) showed a 36% increase in the incidence of this malignancy over the same period. In 1987, overall incidence of invasive breast cancer was 111.9/100,000 women. White women experienced lower overall mortality rates and higher overall incidence than black women; however, these differences varied by age. Examination of breast cancer incidence by stage of disease at diagnosis revealed that rates for distant and regional disease have remained relatively stable since 1973. In contrast, rates of localized and in situ cancers exhibited an increase in the 1980s that may correspond to increased use of mammography in this country. The rate of decline in cervical cancer incidence and mortality has slowed in recent years. In 1987, 3.0 cervical cancer deaths/100,000 women occurred. SEER incidence for invasive disease for that year was 8.2/100,000. Rates varied by race, age, state, and stage of disease. In general, black women experienced much higher incidence and mortality from invasive cervical cancer than white women. For both races, rates of in situ disease were highest among young women and decreased rapidly with age. Rates of in situ cervical cancer were consistently higher than rates of invasive cancer for the time period studied.     

三峡建坝后血吸虫病传播危险因素研究Ⅲ库区血吸虫病监测方案的研究

目的了解三峡库区血吸虫病传播危险因素,为三峡库区血吸虫病动态监测提供技术方案。方法在三峡库区进行钉螺生存模拟试验,调查库区流动人口、家畜血吸虫病传染源和钉螺输入库区的潜在危险因素,以及建坝后社会经济发展变化对血吸虫病传播的潜在影响因素,找出库区血吸虫病监测的重点。结果钉螺在三峡库区的适宜环境中能够生长繁殖;血吸虫病传染源主要是往返于血吸虫病流行区的流动人口;从血吸虫病疫区引进花草树木和牲畜,存在将钉螺和动物传染源输入库区的可能;库区社会经济发展可使血吸虫病传入的危险增加,三峡库区已成为血吸虫病的潜在流行区。结论三峡库区血吸虫病监测工作重点应是流动人口、引进的牲畜等血吸虫病传染源和钉螺输入因素的监测。