Differences between self-referred and physician-referred hospital admissions

Aim  

Compare self- and physician-referred hospital admissions.     

Association between phonocardiographic third and fourth heart sounds and objective measures of left ventricular function

Context  The third (S₃) and fourth (S₄) heart sounds detected by phonocardiography are considered to represent the criterion standards of the gallop sounds, but their test characteristics have not been explored. Objective  To determine the diagnostic test characteristics of the S₃ and S₄ for prediction of left ventricular dysfunction using a computerized heart sound detection algorithm. Design, Setting, and Participants  Prospective study of 90 adult patients undergoing elective left-sided heart catheterization at a single US teaching hospital between August 2003 and June 2004. The mean age was 62 (SD, 13) years (range, 24-90 years) and 61 (68%) were male. Within a 4-hour period, participants underwent computerized heart sound phonocardiographic analysis, cardiac catheterization, transthoracic echocardiography, and blood sampling for assessment of an S₃/S₄, left ventricular end-diastolic pressure (LVEDP), left ventricular ejection fraction (LVEF), and B-type natriuretic peptide (BNP), respectively. Main Outcome Measures  Diagnostic test characteristics of the computerized phonocardiographic S₃ and S₄ using markers of left ventricular function as criterion standards. Results  Mean (SD) LVEDP was significantly elevated (18.4 [6.9] mm Hg vs 12.1 [7.3] mm Hg; P<.001), mean (SD) LVEF was reduced (49.4% [20.2%] vs 63.6% [14.8%]; P<.001), and median (interquartile range) BNP was elevated (330 [98-1155] pg/mL vs 86 [41-192] pg/mL; P<.001) in those with an S₃, S₄, or both compared with patients without a diastolic heart sound. The sensitivities of these heart sounds to detect an elevated LVEDP, reduced LVEF, or elevated BNP were 41%, 52%, and 32% for an S₃, and 46%, 43%, and 40% for an S₄, respectively. For abnormal levels of the same markers of ventricular function, the specificities of the S₃ were 92%, 87%, and 92%, while the specificities of the S₄ were 80%, 72%, and 78%, respectively. Conclusions  Neither the phonocardiographic S₃ nor the S₄ is a sensitive marker of left ventricular dysfunction. The phonocardiographic S₃ is specific for left ventricular dysfunction and appears to be superior to the moderate specificity of the phonocardiographic S₄.      

How to avoid common errors in clinical photography

This paper demonstrates some of the errors commonly seen in both conventional and digital photography when used for clinical purposes, and details how some of these mistakes may be avoided.     

Keratinocyte cell-mediated mutagenesis assay: correlation with in vivo tumor studies

A murine keratinocyte cell-mediated mutagenesis assay was characterizedand examined as an in vitro model system for studying the biotransformationof promutagens/procarcinogens by mouse skin. The assay usedliving cultured newborn SENCAR keratinocytes for the metabolicactivation of promutagens and Chinese hamster lung V-79 fibroblastsfor detection of resulting mutagens. Mutations at, or affecting,the hypoxanthine-guanine phosphoribosyltransferase locus werescored by resisistance to 6-thioguanine. The relative mutagenicitiesof several polycyclic aromatic hydrocarbons (PAHs) in the cell-mediatedassay correlated with the in vivo skin tumongenicity of thePAHs determined in a two-stage carcinogenesis protocol. Metabolicactivation of the promutagenic PAHs to ultimate mutagens wasdependent upon the presence of the cultured keratinocyte feederlayer. 7,8-Benzoflavone, a potent inhibitor of 7, 12-dimethylbenz-[a]anthracene (DMBA)-dependent initiation in mouse skin, inhibitedDMBA-dependent mutagenesis in the cell-mediated assay in a concentrationresponsive manner. The non-PAH promutagens, dimethylnitrosamine(DMN) and sterigmatocystin (STC) were both activated by culturedkeratinocytes to cytotoxic derivatives. DMN was neither mutagenicin the cell-mediated assay nor tumorigenic in mouse skin whentested in a two-stage carcinogenesis protocol. STC was weaklymutagenic and tumorigenic in mouse skin.