Plausible and implausible parameters for mathematical modeling of nominal heterosexual HIV transmission.

Purpose: Several mathematical models simulate a HIV/AIDS epidemic by using the assumption that heterosexual transmission is the major or sole transmission mode. The validity of these models has been unclear. To understand the validity of these models, empirical estimates for relevant model parameters are needed that can be compared with parameters used in mathematical models.

Male and female circumcision associated with prevalent HIV infection in virgins and adolescents in Kenya, Lesotho, and Tanzania.

Purpose: Remarkable proportions of self-reported virgins and adolescents in eastern and southern Africa are infected with HIV, yet non-sexual routes of transmission have not been systematically investigated in such persons. Many observers in this region have recognized the potential for HIV transmission through unhygienic circumcision procedures. We assessed the relation between male and female circumcision (genital cutting) and prevalent HIV infection in Kenyan, Lesothoan, and Tanzanian virgins and adolescents.

Approaches to heart valve tissue engineering scaffold design.

Heart valve disease is a significant cause of mortality worldwide. However, to date, a nonthrombogenic, noncalcific prosthetic, which maintains normal valve mechanical properties and hemodynamic flow, and exhibits sufficient fatigue properties has not been designed. Current prosthetic designs have not been optimized and are unsuitable treatment for congenital heart defects.

Scaffold with a natural mesh-like architecture: isolation, structural, and in vitro characterization.

An intact extracellular matrix (ECM) with a mesh-like architecture has been identified in the peri-muscular sub-serosal connective tissue (PSCT) of cholecyst (gallbladder). The PSCT layer of cholecyst wall is isolated by mechanical delamination of other layers and decellularized with a treatment with peracetic acid and ethanol solution (PES) in water to obtain the final matrix, which is referred to as cholecyst-derived ECM (CEM). CEM is cross-linked with different concentrations of glutaraldehyde (GA) to demonstrate that the susceptibility of CEM to degradation can be controlled.

Biaxial mechanical evaluation of cholecyst-derived extracellular matrix: a weakly anisotropic potential tissue engineered biomaterial.

A new acellular, natural, biodegradable matrix has been discovered in the cholecyst-derived extracellular matrix (CEM). This matrix is rich in collagen and contains several other macromolecules useful in tissue remodeling. In this study, the principal material axes, collagen fiber orientations, and biaxial mechanical properties in a physiological loading regime were characterized.

A transgenic FOXJ1-Cre system for gene inactivation in ciliated epithelial cells.

Ciliated airway epithelial cells are critical for mucosal barrier function, including host defense against pathogens. This cell population is often the primary target and thereby the first line of defense against many common respiratory viruses. It is also the precursor for mucous cells and thereby promotes mucociliary clearance of infectious and other noxious agents.

Circadian rhythms in Neurospora crassa: clock mutant effects in the absence of a frq-based oscillator.

In Neurospora, the circadian rhythm is expressed as rhythmic conidiation driven by a feedback loop involving the protein products of frq (frequency), wc-1 (white collar-1), and wc-2, known as the frq/wc (FWC) oscillator. Although strains carrying null mutations such as frq(10) or wc-2Delta lack a functional FWC oscillator and do not show a rhythm under most conditions, a rhythm can be observed in them by the addition of geraniol or farnesol to the media. Employing this altered media as an assay, the effect of other clock mutations in a frq(10)- or wc-2Delta-null background can be measured.

Lack of autodisable syringe use and health care indicators are associated with high HIV prevalence: an international ecologic analysis.

Purpose: A growing body of evidence strongly suggests that unsafe health care is an important factor driving the human immunodeficiency virus (HIV) epidemic in sub-Saharan Africa. We investigate whether nonuse of autodisable syringes and other health care indicators predict national HIV prevalence.

Methods: These ecologic analyses use countries as study units in descriptive analyses and regression analyses.

The effect of cholecyst-derived extracellular matrix on the phenotypic behaviour of valvular endothelial and valvular interstitial cells.

Cholecyst-derived extracellular matrix (CEM) is a novel, proteinaceous biomaterial, derived from the porcine cholecyst, which may have potential applications as a scaffold in the area of heart valve tissue engineering. In this study the potential of CEM to support the proliferation of valvular endothelial cells (VECs) and valvular interstitial cells (VICs), while maintaining their phenotypic mRNA synthesis, protein expression and morphology was assessed by biochemical assays, electron microscopy, immunostaining and reverse-transcriptase polymerase chain reaction. VICs and VECs were isolated from the porcine aortic valve and techniques were developed for the isolation of CEM for cell culture.

Regulation of lipopolysaccharide-induced increases in neutrophil glucose uptake.

The pathogenesis of many lung diseases involves neutrophilic inflammation. Neutrophil functions, in turn, are critically dependent on glucose uptake and glycolysis to supply the necessary energy to meet these functions. In this study, we determined the effects of p38 mitogen-activated protein kinase and hypoxia-inducible factor (HIF)-1, as well as their potential interaction, on the expression of membrane glucose transporters and on glucose uptake in murine neutrophils.

The role of health care in the spread of HIV/AIDS in Africa: evidence from Kenya.

It is commonly asserted that the sub-Saharan African HIV/AIDS epidemic is predominantly due to heterosexual transmission. However, recent re-examination of the available evidence strongly suggests that unsafe health care is the more likely vector. The present report adds to the evidence for health-care transmission by showing that Kenyan women who received prophylactic tetanus toxoid injections during pregnancy are 1.

Trefoil factor family 3 peptide promotes human airway epithelial ciliated cell differentiation.

Human airway surface epithelium is frequently damaged by inhaled factors (viruses, bacteria, xenobiotic substances) as well as by inflammatory mediators that contribute to the shedding of surface epithelial cells. To regain its protective function, the epithelium must rapidly repair and redifferentiate. The Trefoil Factor Family (TFF) peptides are secretory products of many mucous cells.

Identifying potential conflict associated with oil and gas exploration in Texas state coastal waters: A multicriteria spatial analysis.

Recent interest in expanding offshore oil production within waters of the United States has been met with opposition by groups concerned with recreational, environmental, and aesthetic values associated with the coastal zone. Although the proposition of new oil platforms off the coast has generated conflict over how coastal resources should be utilized, little research has been conducted on where these user conflicts might be most intense and which sites might be most suitable for locating oil production facilities in light of the multiple, and often times, competing interests. In this article, we develop a multiple-criteria spatial decision support tool that identifies the potential degree of conflict associated with oil and gas production activities for existing lease tracts in the coastal margin of Texas.

Student perceptions of the effectiveness of education in the responsible conduct of research.

Responsible conduct of research (RCR) courses are widely taught, but little is known about the purposes or effectiveness of such courses. As one way to assess the purposes of these courses, students were surveyed about their perspectives after recent completion of one of eleven different research ethics courses at ten different institutions. Participants (undergraduate and graduate students, post-doctoral fellows and faculty, staff and researchers) enrolled in RCR courses in spring and fall of 2003 received a voluntary, anonymous survey from their instructors at the completion of the course.

Influenza virus receptor specificity and cell tropism in mouse and human airway epithelial cells.

Recent human infections caused by the highly pathogenic avian influenza virus H5N1 strains emphasize an urgent need for assessment of factors that allow viral transmission, replication, and intra-airway spread. Important determinants for virus infection are epithelial cell receptors identified as glycans terminated by an alpha2,3-linked sialic acid (SA) that preferentially bind avian strains and glycans terminated by an alpha2,6-linked SA that bind human strains. The mouse is often used as a model for study of influenza viruses, including recent avian strains; however, the selectivity for infection of specific respiratory cell populations is not well described, and any relationship between receptors in the mouse and human lungs is incompletely understood.

Characterizing nanoscale topography of the aortic heart valve basement membrane for tissue engineering heart valve scaffold design.

A fully effective prosthetic heart valve has not yet been developed. A successful tissue-engineered valve prosthetic must contain a scaffold that fully supports valve endothelial cell function. Recently, topographic features of scaffolds have been shown to influence the behavior of a variety of cell types and should be considered in rational scaffold design and fabrication.

Blocking airway mucous cell metaplasia by inhibiting EGFR antiapoptosis and IL-13 transdifferentiation signals.

Epithelial hyperplasia and metaplasia are common features of inflammatory and neoplastic disease, but the basis for the altered epithelial phenotype is often uncertain. Here we show that long-term ciliated cell hyperplasia coincides with mucous (goblet) cell metaplasia after respiratory viral clearance in mouse airways. This chronic switch in epithelial behavior exhibits genetic susceptibility and depends on persistent activation of EGFR signaling to PI3K that prevents apoptosis of ciliated cells and on IL-13 signaling that promotes transdifferentiation of ciliated to goblet cells.

A synthetic, chloride-selective channel that alters chloride transport in epithelial cells.

An Ussing chamber was used to demonstrate that synthetic amphiphilic anion transporters function as chloride transporters in mammalian airway epithelial cells.

Pseudomonas aeruginosa acquires biofilm-like properties within airway epithelial cells.

Pseudomonas aeruginosa can notably cause both acute and chronic infection. While several virulence factors are implicated in the acute phase of infection, advances in understanding bacterial pathogenesis suggest that chronic P. aeruginosa infection is related to biofilm formation.