Prisoners of the proximate: loosening the constraints on epidemiology in an age of change.
"Modern epidemiology" has a primary orientation to the study of multiple risk factors for chronic noncommunicable diseases. If epidemiologists are to understand the determinants of population health in terms that extend beyond proximate, individual-level risk factors (and their biological mediators), they must learn to apply a social-ecologic systems perspective. The mind-set and methods of modern epidemiology entail the following four main constraints that limit engagement in issues of wider context: 1) a preoccupation with proximate risk factors; 2) a focus on individual-level versus population-level influences on health; 3) a typically modular (time-windowed) view of how individuals undergo changes in risk status (i.e., a life-stage vs. a life-course model of risk acquisition); and 4) the, as yet, unfamiliar challenge of scenario-based forecasting of health consequences of future, large-scale social and environmental changes. The evolution of the content and methods of epidemiology continues. Epidemiologists are gaining insights into the complex social and environmental systems that are the context for health and disease; thinking about population health in increasingly ecologic terms; developing dynamic, interactive, life-course models of disease risk acquisition; and extending their spatial-temporal frame of reference as they perceive the health risks posed by escalating human pressures on the wider environment. The constraints of "the proximate" upon epidemiology are thus loosening as the end of the century approaches. (+info)
Reconstruction of a historical genealogy by means of STR analysis and Y-haplotyping of ancient DNA.
Archaeological excavations in St Margaretha's church at Reichersdorf, Germany, in 1993 led to the discovery of eight skeletons, so far assumed to be of the Earls of Konigsfeld, who used the church as a family sepulchre over a period of seven generations from 1546 to 1749. DNA-based sex testing and analysis of autosomal short tandem repeat systems (STR) was carried out to confirm the assumption of kinship. Since five of the individuals were determined as males, analysis of Y-specific STRs seemed feasible. A comparison of Y-haplotypes revealed that one individual could not be linked to the Konigsfeld patrilineage, an observation supported by autosomal STR evidence. Two individuals typed as females posed an identification problem, since supposedly only male members of the family were buried in St Margaretha's. Nevertheless, these individuals could tentatively be identified as members of the House of Konigsfeld through genetic fingerprinting. (+info)
A bit of history.
Reviews of scientific literature began to appear in the 17th century. Journals dedicated to them soon followed, leading eventually to this one, which emerged in the 1930s as Bacteriological Reviews; it adapted to the many changes in our fluid discipline, evolving into the present, much broader Microbiology and Molecular Biology Reviews. (+info)
Fin-de-siecle Philadelphia and the founding of the Medical Library Association.
Philadelphia at the time of the founding of the Medical Library Association (MLA) is described. Several factors that promoted the birth of the association are discussed, including the rapid increase in the labor force and the rise of other health related professions, such as the American Hospital Association and the professionalization of nursing. The growth of the public hygiene movement in Philadelphia at the time of Sir William Osler's residency in the city is discussed. Finally, the rapid growth of the medical literature is considered a factor promoting the development of the association. This article continues the historical consideration of the MLA begun in the author's article on the three founders of the association. The background information is drawn from the items listed in the bibliography, and the conclusions are those of the author. (+info)
Early use of 'open-air' treatment for 'pulmonary phthisis' at the Dreadnought Hospital, Greenwich, 1900-1905.
The use of open-air treatment for tuberculosis ('pulmonary phthisis') at the Dreadnought Hospital, Greenwich from 1900 to 1905 is reviewed. A marked reduction in mean mortality rate compared to 'orthodox' management was observed. (+info)
Identification of Treponema pallidum subspecies pallidum in a 200-year-old skeletal specimen.
Treponema pallidum subsp. pallidum, the causative agent of venereal syphilis, was detected in a 200-year-old skeletal specimen from Easter Island. An initial diagnosis of treponemal infection was confirmed by extensive purification of immunoglobulin that reacted strongly with T. pallidum antigen. Extracted DNA exhibited a single-base polymorphism that distinguished T.p. subsp. pallidum from 4 other human and nonhuman treponemes. Extensive precautions against contamination of the subject matter with modern treponemal DNA were employed, including analysis of archaeological and modern specimens in 2 geographically separate laboratories. Molecular determination of historical disease states by using skeletal material can significantly enhance our understanding of the pathology and spread of infectious diseases. (+info)
Two closely linked mutations in Drosophila melanogaster that are lethal to opposite sexes and interact with daughterless.
A new spontaneous mutation named Sex-lethal, Male-specific No. 1 (SxlM1) is described that is lethal to males, even in the presence of an Sxl+ duplication. Females homozygous for SxlM1 are fully viable. This dominant, male-specific lethal mutation is on the X chromosome approximately 0.007 map units to the right of a previously isolated female-specific mutation, Female-lethal, here renamed Sex-lethal, Female-specific No. 1 (SxlF1). SxlM1 and SxlF1 are opposite in nearly every repect, particularly with regard to their interaction with maternal effect of the autosomal mutation, daughterless (da). Females that are homozygous for da produce defective eggs that cannot support female (XX) development. A single dose of SxlM1 enables daughters to survive this da female-specific lethal maternal effect. A duplication of the Sxl locus weakly mimics this action of SxlM1. In contrast, SxlF1 and a deficiency for Sxl, strongly enhance the female-lethal effects of da. The actions of SxlM1 and SxlF1 are explained by a model in which expression of the Sxl locus is essential for females, lethal for males, and under the control of a product of the da locus. It is suggested that SxlM1 is a constitutive mutation at the Sxl locus. (+info)
The effect of recombination-defective meiotic mutants on fourth-chromosome crossing over in Drosophila melanogaster.
Crossing over was measured on the normally achiasmate fourth chromosome in females homozygous for one of our different recombination-defective meiotic mutants. Under the influence of those meiotic mutants that affect the major chromosomes by altering the spatial distribution of exchanges, meiotic fourth-chromosome recombinants were recovered irrespective of whether or not the meiotic mutant decreases crossing over on the other chromosomes. No crossing over, on the other hand, was detected on chromosome 4 in either wild type or in the presence of a meiotic mutant that decreases the frequency, but does not affect the spatial distribution, of exchange on the major chromosomes. It is concluded from these observations that (a) in wild type there are regional constraints on exchange that can be attenuated or eliminated by the defects caused by recombination-defective meiotic mutants; [b] these very constraints account for the absence of recombination on chromosome 4 in wild type; and [c] despite being normally achiasmate, chromosome 4 responds to recombination-defective meiotic mutants in the same way as do the other chromosomes. (+info)