“In the 1990s Black reviewed thirty-six studies of South American Indians. Not to his surprise, he discovered that overall Indians have fewer HLA types than populations from Europe, Asia, and Africa. European populations have at least thirty-five main HLA classes, whereas Indian groups have no more than seventeen. In addition, Native American HLA profiles are dominated by an unusually small number of types. About one third of South American Indians, Black discovered, have identical or near-identical HLA profiles; for Africans the figure is one in two hundred. In South America, he estimated, the minimum probability that a pathogen in one host will next encounter a host with similar immune spectrum is about 28%; in Europe, the chance is less than 2%. As a result, Black argued, that people of the New World are unusually susceptible to diseases of the old.” (Mann, Charles C. 1491. New Revelations of the Americas before Columbus. New York: Alfred A Knopf, 2005:104–5)

All obesity studies would agree that Americans are much more likely to be overweight than Europeans. In contrast, Europeans are likely to smoke much more than Americans. Only 19% of adult Americans smoke, whereas 34% of Germans and 27% of Britons do. Investigators from Harvard University tried to answer why there was this increased rate of smoking in Europe. Cost of cigarettes does not seem to be the issue since cigarettes are 37% cheaper in America. The conclusion of the authors was that information is the primary difference. Only 73% of Germans believe smoking is dangerous whereas 91% of Americans do. The implications of this study obviously suggest that further public health measures and campaigns to discourage smoking, particularly in Europe, are warranted. (Go to: www.nber.org/papers/w12124)

Progressive supranuclear palsy (PSP) is the second most common neurodegenerative extrapyramital disorder after Parkinson’s disease. Because of the prominent ocular motor difficulties in this disorder ophthalmologists are often the first physicians to evaluate these patients. Investigators from Italy have recently used voxel based morphometry and diffusion tensor imaging to investigate the pathological nature of this disease. In this study the investigators demonstrated that even in very early PSP both grey and white matter degeneration occurs. This study suggests that structural methods of this type can help to differentiate PSP from other neurodegenerative diseases with extrapyramital symptoms even in its earliest phases. (

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The annual cost to the United States of diabetes is upwards of $132 billion. Autism costs more than $43 billion and asthma approaches nearly $11 billion. Thus one would assume that spending $100 million in the next 20 years to better understand the origin of these conditions would be financially prudent. Nevertheless, President George W Bush has proposed to eliminate from the 2007 budget the National Children’s Study designed to ferret out the causes of these three major health disorders. Congress may re-establish funds for this project but the indications are that it is likely not to be fully funded. (

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Why colour vision developed in humans and related primates is a question still to be answered. Birds and bees have colour receptors that are evenly sensitive across the spectrum whereas two of the three kinds of colour photoreceptors in humans and old world primates are both most sensitive to roughly the 550 nm wavelength of light. Investigators from the California Institute of Technology suggest that this sensitivity is optimised towards detecting subtle changes in skin tone because of varying concentrations of oxygenated haemoglobin in the blood. They further suggest that this would help primates determine if a potential mate is “rosy” and in good health or if an enemy is blanched with alarm. (Biology Letters 22 June 2006)

Roche has recently announced deals with other pharmaceutical companies to dramatically ramp up production of oseltamiver (Tamiflu) in 2007. This will give it a capacity to produce 400 million treatment courses annually. This would be an increase from six million courses produced just 3 years ago. While the supply will increase in availability it is not clear that the cost will decrease. Roche still plans to charge developing countries approximately $15 per treatment course, whereas rich countries will pay $18 per course. (

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Creating a continuous curvilinear caspulorrhexis in an eye with a white mature cataract can be challenging because it is difficult to distinguish the anterior capsule from the underlying white cortex. Several techniques have been developed to try to enhance the visibility of the anterior capsule in this circumstance. Recently the use of brilliant blue G for capsular visualisation has been advocated. Investigators from Fukuoka, Japan, have evaluated brilliant blue G staining ability and biocompatibility. In this study brilliant blue G contributed to better capsular visualisation and caused no apparent complications to the corneal endothelium. Apoptotic cell death of the endothelial cells was only detected in a control group studied with trypan blue. The authors conclude, therefore, that brilliant blue G is a good alternative dye for capsular staining with superior staining ability and excellent biocompatibility. (

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In humans, microsporidia are opportunistic pathogens that are reported to cause gastrointestinal, sinus, pulmonary, muscular, renal, and ocular disease primarily in immunocompromised patients. Investigators from the Prasad Eye Institute in India report a study of 19 cases of microsporidial keratoconjunctivitis in immunocompetent individuals. In this study the authors concluded that microsporidial keratoconjunctivitis should be considered in the differential diagnosis of atypical punctuate epithelial keratitis associated with conjunctivitis. It can be diagnosed by routine microbiological methods. They emphasise that the disease can occur in healthy individuals and the outcome of treatment is often satisfactory. (

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Although the surgical treatment of infantile esotropia is usually successful in establishing a cosmetically acceptable ocular motor alignment even peripheral fusion can be difficult to establish. It remains to be seen if true foveal fusion can be established in these patients. Jampolsky has suggested that alternative occlusion therapy before surgery might enhance the ocular motor outcomes. In a multicentre study investigators completed a prospective study of alternate occlusion before surgical alignment for infantile esotropia. Alternating occlusion did not increase the angle of deviation before surgery nor did it increase the likelihood of good surgical alignment postoperatively. The outcome of the control group and the alternating occlusion group in this study were identical. (

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