The Case of the Positive Pregnancy Pretender: A Potential Cause of Erroneous Test Results in Active-Duty Personnel.

The detection of pregnancy is common among those who participate in the care of reproductive-age females. This is especially true in the medical care of active-duty personnel in the armed forces. Considering the impact of a positive urine pregnancy test in this population, it is important to recognize the possibility of false-positive results and their causes.

Cone outer segments: a biophysical model of membrane dynamics, shape retention, and lamella formation.

An hypothesis is developed to explain how the unique, right circular conical geometry of cone outer segments (COSs) in Xenopus laevis and other lower vertebrates is maintained during the cycle of axial shortening by apical phagocytosis and axial elongation via the addition of new basal lamellae. Extension of a new basal evagination (BE) applies radial (lateral) traction to membrane and cytoplasmic domains, achieving two coupled effects. 1), The bilayer domain is locally stretched/dilated, creating an entropic driving force that draws membrane components into the BE from the COS's distributed bilayer phase, i.

A simplified mass-transfer model for visual pigments in amphibian retinal-cone outer segments.

When radiolabeled precursors and autoradiography are used to investigate turnover of protein components in photoreceptive cone outer segments (COSs), the labeled components--primarily visual pigment molecules (opsins)--are diffusely distributed along the COS. To further assess this COS labeling pattern, we derive a simplified mass-transfer model for quantifying the contributions of advective and diffusive mechanisms to the distribution of opsins within COSs of the frog retina. Two opsin-containing regions of the COS are evaluated: the core axial array of disks and the plasmalemma.

Association of Birth Weight with Health and Long-Term Survival up to Middle and Old Ages in China.

This study is based on an unique dataset of birth records of 11,693 persons born in Beijing, China from 1921-54 and from clinical examinations (May 2003-April 2005) of 2,085 tracked surviving cohort members (aged 50-82) to diagnose seven major chronic diseases. Data were analyzed using the extended Fixed Attribute Dynamics (FAD) method and multivariate regressions. The results of our FAD analysis have shown that, as compared to the persons with low birth weight (<2,500 g), the probability of survival from age 0 to ages 50-56, 63-67 and 68-82 for persons with higher birth weight (2,500-2,999 g, 3,000-3499 g, or ≥3,500 g) was 16-31, 62-104, and 52-108% higher respectively.

The use of leukotriene modifying drugs in asthma and other respiratory diseases.

Only rarely in modern medicine is an entirely new class of drug developed. Recently, a number of drugs that act as leukotriene modifiers (LTM's) have been licensed for use in the treatment of asthma. Airway obstruction in asthma has two key components--bronchoconstriction of airway smooth muscle and airway inflammation.