Why HIV-1 has diffused so much more rapidly in Sub-Saharan Africa than in North America.

AIDS was first identified in Sub-Saharan Africa and North America in the early 1980s. Over the past twenty years, however, HIV-1 has diffused much more rapidly in the former continent than in latter. This appears to be because the virus cannot diffuse well in local populations that have an adequate dietary intake of selenium.

Why the preeminent risk factor in sporadic Alzheimer's disease cannot be genetic.

If genetic risk factors are preeminent in the etiology of sporadic Alzheimer's disease, three corollaries follow: age-adjusted death rates from it should be fairly spatially uniform, should not vary significantly over time and should not alter markedly with migration. Globally, none of these corollaries hold true. The APO E(4) allele and other genetic aberrations that promote sporadic Alzheimer's disease do so most effectively in low alkalinity-high aluminum environments, especially if these are experiencing acid rain.

Landscapes of longevity: the calcium-selenium-mercury connection in cancer and heart disease.

Cancer and heart disease display spatial patterns that suggest the possible involvement of calcium and selenium deficiencies and mercury excess in their aetiologies. As a consequence, longevity tends to be most common in regions where the environment is calcium- and selenium-enriched but contains only low levels of mercury. Examples are cited from West Africa, China, England and the USA.

Longevity and selenium deficiency: evidence from the People's Republic of China.

Data were abstracted from the Atlas of Aged Population in the People's Republic of China and from The Atlas of Endemic Diseases and their Environments in the People's Republic of China. The spatial distribution of the elderly, those aged 80 years or more in 1982, in 2408 counties, was then compared with the prevalences of Kaschin-Beck and Keshan diseases, both of which involve extreme selenium deficiency. Pearson chi-square, the Mantel-Haenszel test for linear, association and Spearman correlation all clearly indicate that the elderly in China are not normally distributed. Far fewer people of advanced age reside in those counties in which Kaschin-Beck and Keshan diseases are endemic than in unaffected counties. The possible reasons for this are thought to include elevated mortality from endemic and chronic diseases in selenium deficient areas and accelerated ageing due to excessive cellular damage caused by free radicals. These two phenomena may be related.

The iodine-selenium connection: its possible roles in intelligence, cretinism, sudden infant death syndrome, breast cancer and multiple sclerosis.

Several diseases and disorders display spatial patterns that suggest the involvement of both selenium and iodine deficiencies, or excesses, in their etiologies. It is suggested that many of these similarities in geographical distribution occur because both elements influence thyroid hormone metabolism.

A survey of patients' attitudes towards inpatient psychiatric ward rounds.

Attitudes towards the multidisciplinary ward round were assessed in fifty psychiatric inpatients, from two wards, using a semi-structured interview. About three quarters of them had at least a moderately favourable impression of the ward round but more than half would still prefer not to be interviewed in this way. Levels of anxiety and perceived helpfulness were positively correlated. Afro-Caribbeans found the interview significantly less helpful, less understandable and less memorable. Men found it less helpful than women and there were differences found between the two wards. Possible explanations for these findings are discussed.

A survey of patients' attitudes towards inpatient psychiatric ward rounds

Attitudes towards the multidisciplinary ward round were assessed in fifty psychiatric inpatients, from two wards, using a semi-structures interview. About three quarters of them had at least a moderately favourable impression of the ward round but more than half would still prefer not to be interviewed in this way. Levels of anxiety and perceived helpfulness were positively correlated. Afro-Caribbeans found the interview significantly less helpful, less understandable and less memorable. Men found it less helpful than women and there were differences found between the two wards. Possible explanations for these findings are discussed. (AU)

Disease family trees: the possible roles of iodine in goitre, cretinism, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's and Parkinson's diseases and cancers of the thyroid, nervous system and skin.

Geographical distribution patterns of incidence and mortality for a wide variety of diseases display strong positive and negative correlations when analyzed statistically. It is argued that these relationships do not occur by chance, but reflect the causal role of surpluses and/or deficiencies of various bulk and trace elements. This concept is explored for one such "disease family tree", that of iodine. Deficiencies of this essential trace element appear to be associated with many diseases, or birth defects, including goitre, cretinism, multiple sclerosis, amyotrophic lateral sclerosis and cancer of the thyroid and nervous system. Although the evidence is weaker, iodine deficiency may also be implicated in Alzheimer's and Parkinson's diseases. In contrast, too much iodine may be linked to elevated mortality from cancer of the skin and melanoma. Rat studies indicate that iodine deficiencies can cause reduced brain weight, limited myelin formation, retarded neuronal maturation, a lowering of the production of various enzymes and slowing of the rates of protein and R.N.A. synthesis. Similar processes appear to occur in many of the diseases identified above.