The pneumococcus at the millennium: not down, not out.
(9/5154)
In the 12 decades that will have elapsed between the first isolation of the pneumococcus and the coming millennium, much of fundamental biologic importance has been learned from the study of this bacterium and the diseases it causes. Streptococcus pneumoniae is associated with the development of Gram's stain, the Quellung reaction, and many of the fundamentals of immunology. It has also played a significant role in the history of antimicrobial therapy. After a transitory period of euphoria engendered by the improved prognosis of pneumococcal pneumonia resulting from therapeutic advances, recognition that the newer treatments could not bring about the recovery of those sustaining early irreversible physiologic injury led to renewed interest in immunoprophylaxis. Added impetus to this approach has been fostered by the recent rapid increase in the number of pneumococcal isolates resistant to antimicrobial agents and in the magnitude of their resistance. Pneumococcal vaccines are increasingly relevant. (+info)
Documenting the diet in ancient human populations through stable isotope analysis of hair.
(10/5154)
Fundamental to the understanding of human history is the ability to make interpretations based on artefacts and other remains which are used to gather information about an ancient population. Sequestered in the organic matrices of these remains can be information, for example, concerning incidence of disease, genetic defects and diet. Stable isotopic compositions, especially those made on isolates of collagen from bones, have been used to help suggest principal dietary components. A significant problem in the use of collagen is its long-term stability, and the possibility of isotopic alteration during early diagenesis, or through contaminating condensation reactions. In this study, we suggest that a commonly overlooked material, human hair, may represent an ideal material to be used in addressing human diets of ancient civilizations. Through the analysis of the amino-acid composition of modern hair, as well as samples that were subjected to radiation (thus simulating ageing of the hair) and hair from humans that is up to 5200 years old, we have observed little in the way of chemical change. The principal amino acids observed in all of these samples are essentially identical in relative abundances and content. Dominating the compositions are serine, glutamic acid, threonine, glycine and leucine, respectively accounting for approximately 15%, 17%, 10%, 8% and 8% of the total hydrolysable amino acids. Even minor components (for example, alanine, valine, isoleucine) show similar constancy between the samples of different ages. This constancy clearly indicates minimal alteration of the amino-acid composition of the hair. Further, it would indicate that hair is well preserved and is amenable to isotopic analysis as a tool for distinguishing sources of nutrition. Based on this observation, we have isotopically characterized modern individuals for whom the diet has been documented. Both stable nitrogen and carbon isotope compositions were assessed, and together provide an indication of trophic status, and principal type (C3 or C4) of vegetation consumed. True vegans have nitrogen isotope compositions of about 7/1000 whereas humans consuming larger amounts of meat, eggs, or milk are more enriched in the heavy nitrogen isotope. We have also analysed large cross-sections of modern humans from North America and Europe to provide an indication of the variability seen in a population (the supermarket diet). There is a wide diversity in both carbon and nitrogen isotope values based at least partially on the levels of seafood, corn-fed beef and grains in the diets. Following analysis of the ancient hair, we have observed similar trends in certain ancient populations. For example, the Coptics of Egypt (1000 BP) and Chinchorro of Chile (5000-800 BP) have diets of similar diversity to those observed in the modern group but were isotopically influenced by local nutritional sources. In other ancient hair (Egyptian Late Middle Kingdom mummies, ca. 4000 BP), we have observed a much more uniform isotopic signature, indicating a more constant diet. We have also recognized a primary vegetarian component in the diet of the Neolithic Ice Man of the Oetztaler Alps (5200 BP). In certain cases, it appears that sulphur isotopes may help to further constrain dietary interpretations, owing to the good preservation and sulphur content of hair. It appears that analysis of the often-overlooked hair in archaeological sites may represent a significant new approach for understanding ancient human communities. (+info)
Early medieval cattle remains from a Scandinavian settlement in Dublin: genetic analysis and comparison with extant breeds.
(11/5154)
A panel of cattle bones excavated from the 1000-year-old Viking Fishamble Street site in Dublin was assessed for the presence of surviving mitochondrial DNA (mtDNA). Eleven of these bones gave amplifiable mtDNA and a portion of the hypervariable control region was determined for each specimen. A comparative analysis was performed with control region sequences from five extant Nordic and Irish cattle breeds. The medieval population displayed similar levels of mtDNA diversity to modern European breeds. However, a number of novel mtDNA haplotypes were also detected in these bone samples. In addition, the presence of a putative ancestral sequence at high frequency in the medieval population supports an early post-domestication expansion of cattle in Europe. (+info)
Freezer anthropology: new uses for old blood.
(12/5154)
Archived blood fractions (plasma, settled red cells, white cells) have proved to be a rich and valuable source of DNA for human genetic studies. Large numbers of such samples were collected between 1960 and the present for protein and blood group studies, many of which are languishing in freezers or have already been discarded. More are discarded each year because the usefulness of these samples is not widely understood. Data from DNA derived from 10-35-year-old blood samples have been used to address the peopling of the New World and of the Pacific. Mitochondrial DNA haplotypes from studies using this source DNA support a single wave of migration into the New World (or a single source population for the New World), and that Mongolia was the likely source of the founding population. Data from Melanesia have shown that Polynesians are recent immigrants into the Pacific and did not arise from Melanesia. (+info)
Early theory and research on hemispheric specialization.
(13/5154)
This article provides an account of early theory and research on hemispheric specialization. It begins by tracing theory and research on localization of function that set the stage for the discovery of hemispheric specialization. After that, it describes the studies of Paul Broca, John Hughlings-Jackson, and others on hemisphere specialization and reviews some of the proposed explanations for the phenomenon. It then turns to the study of hemispheric specialization and mental illness, and it ends by identifying some of the linkages between theory and research from the past and the present. (+info)
An appreciation of A.E. Malloch, MB, MD (1844-1919): a forgotten surgical pioneer.
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Dr. Archibald Edward Malloch was a surgeon whose life and work were greatly influenced by Joseph Lister and his revolutionary system of antiseptic surgery. This paper describes how a young Canadian medical man came to introduce Lister's system to North America in 1869 and studies his career in the light of Lister's surgical epoch. (+info)
Driving through: postpartum care during World War II.
(15/5154)
In 1996, public outcry over shortened hospital stays for new mothers and their infants led to the passage of a federal law banning "drive-through deliveries." This recent round of brief postpartum stays is not unprecedented. During World War II, a baby boom overwhelmed maternity facilities in American hospitals. Hospital births became more popular and accessible as the Emergency Maternal and Infant Care program subsidized obstetric care for servicemen's wives. Although protocols before the war had called for prolonged bed rest in the puerperium, medical theory was quickly revised as crowded hospitals were forced to discharge mothers after 24 hours. To compensate for short inpatient stays, community-based services such as visiting nursing care, postnatal homes, and prenatal classes evolved to support new mothers. Fueled by rhetoric that identified maternal-child health as a critical factor in military morale, postpartum care during the war years remained comprehensive despite short hospital stays. The wartime experience offers a model of alternatives to legislation for ensuring adequate care of postpartum women. (+info)
The Framingham Offspring Study: a commentary. 1980.
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Forty-three of 1,312 men aged 35 to 54 years in the Framingham Offspring Study had clinically recognized coronary heart disease at the initial examination. Twenty-six men in this group had previously had a myocardial infarction. Of 1,296 women in the same age range, only 11 had coronary disease and 3 a prior myocardial infarction. The prevalence of coronary heart disease in men was strongly associated with age, smoking, high density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol using univariate analyses. When multivariate logistic regression analysis was used, age, smoking and HDL and LDL cholesterol retained their significant association with coronary heart disease. The total cholesterol/HDL cholesterol ratio was also strongly associated with coronary heart disease in the multivariate analysis. It is concluded that both HDL and LDL cholesterol are strongly and independently associated with the prevalence of coronary heart disease, whereas the level of very low density lipoprotein cholesterol makes no statistically significant independent contribution. (+info)