Detail and generality in mechanistic explanation.

This article is about the role of abstraction in mechanistic explanations. Abstraction is widely recognised as a necessary concession to the practicalities of scientific work, but some mechanist philosophers argue that it is also a positive explanatory feature in its own right. I claim that in as much as these arguments are based on the idea that mechanistic explanation exhibits a trade-off between fine-grained detail and generality, they are unsuccessful. Detail and generality both appear to be important sources of explanatory power, but investigators do not need to make a choice between these desiderata, at least when an explanation incorporates further detail through the decomposition of the mechanism's parts.

Biological Criteria of Disease: Four Ways of Going Wrong.

We defend a view of the distinction between the normal and the pathological according to which that distinction has an objective, biological component. We accept that there is a normative component to the concept of disease, especially as applied to human beings. Nevertheless, an organism cannot be in a pathological state unless something has gone wrong for that organism from a purely biological point of view. Biology, we argue, recognises two sources of biological normativity, which jointly generate four "ways of going wrong" from a biological perspective. These findings show why previous attempts to provide objective criteria for pathology have fallen short: Biological science recognizes a broader range of ways in which living things can do better or worse than has previously been recognized in the philosophy of medicine.

Toward point-of-care diagnostic metabolic fingerprinting: quantification of plasma creatinine by infrared spectroscopy of microfluidic-preprocessed samples.

Infrared (IR) spectroscopy has previously been established as a means to accurately quantify several serum and urine metabolites, based upon spectroscopy of dry films. The same technique has also provided the basis to develop certain diagnostic tests, developed in the 'metabolomics' spirit. Here, we report on the further development of an integrated microfluidic-IR technology and technique, customized with the aim of dramatically extending the capabilities of IR spectroscopy in both analytical and diagnostic (metabolomic) applications. By exploiting the laminar fluid diffusion interface (LFDI), serum specimens are processed to yield product streams that are better suited for metabolic fingerprinting; metabolites are captured within the aqueous product stream, while proteins (which otherwise dominate the spectra of films dried from serum) are present in much reduced concentration. Spectroscopy of films dried from the aqueous stream then provides enhanced diagnostic and analytical sensitivity. The manuscript introduces an LFDI card design that is customized for integration with IR spectroscopy, and details the development of a quantitative assay for serum creatinine--based upon LFDI-processed serum samples--that is substantially more accurate (standard error of calibration, SEC = 43 micromol/L) than the corresponding assay based upon unprocessed serum specimens (SEC = 138 micromol/L). Preliminary results of diffusion modeling are reported, and the prospects for further optimization of the technique, guided by accurate modeling, are discussed.

Epidemiology, etiology, and impact of traveler's diarrhea in Jamaica

CONTEXT: Traveler's diarrhea (TD) can incapacitate travelers. Characteristics of TD could be helpful in identifying individuals who might benefit from a vaccine against TD. OBJECTIVE: To determine epidemiology, etiology, and impact of TD in Jamaica. DESIGN: Two-armed, cross-sectional survey conducted between March 1996 and May 1997. SETTING: To investigate epidemiology and impact, 30369 short-term visitors completed a questionnaire just before boarding their homebound aircrafts. To investigate etiology, 322 patients (hotel guests) with TD provided stool samples. MAIN OUTCOME MEASURES: Attack and incidence rates of reported diarrhea and of classically defined TD (> or = 3 unformed stool samples in 24 hours and > or = 1 accompanying symptom), incapacity, risk factors, and etiology. RESULTS: The attack rate for diarrhea was 23.6 percent overall, with 11.7 percent having classically defined TD. For a mean duration of stay of 4 to 7 days, the incidence rate was 20.9 percent (all TD) and 10.0 percent (classic TD). Among airport respondents, the incapacity lasted a mean of 11.6 hours. Less than 3 percent of all travelers avoided potentially high-risk food and beverages. The most frequently detected pathogens were enterotoxigenic Escherichia coli, Rotavirus, and Salmonella species. CONCLUSIONS: A realistic plan for reducing TD is needed. Preventive measures such as the improvement of hygienic conditions at the destination, and/or the development of vaccines against the most frequent pathogens associated with TD may contribute toward achieving this goal (Au)

The aetiology of diarrhoea in five hotels in Jamaica

Diarrhoea is a self-limited disease which commonly affects tourists traveling from low risk to high risk destinations. It is estimated to affect 20-50 percent of the residents of industrialized countries who visit a developing country each year. Jamaica and other countries of the Caribbean, Latin America, Sub-Saharan African and South East Asia are considered to be intermediate to high risk tourist destinations. Data generated between 1979 and 1981 estimated that approximately 20 percent of European visitors to the Caribbean are afflicted with travellers' diarrhoea (TD) during their stay. Since the time, tourist arrivals to Jamaica have increased from 0.4 to 1.2 millions. To meet the challenges faced by this rapid growth, significant changes have been made to the tourism product, which may have impacted on the health visitors. Immediately following Jamaica's citation by the US Travel Advisory after an outbreak of typhoid in the parish of Westmoreland in 1991, the country was faced by a threat of a cholera epidemic in neighbouring Latin America. With a view to implementing a strategy for cholera prevention and control of cholera and other foodborne diseases, the Ministry of Health initiated a study of epidemiology and aetiology of TD in Jamaica. The first phase of the study was designed to assess the magnitude of TD amongst travellers to Jamaica, by region and by hotel. Those data have been reported elsewhere. Bacterial enteropathogens cause 80 percent of TD.(AU)