Healing of a large bronchoesophageal fistula secondary to hodgkin lymphoma managed with a removable esophageal stent.

We describe the management of a large bronchoesophageal fistula secondary to Hodgkin lymphoma with a fully covered self-expanding metallic stent.

Early expression profile of inflammatory markers and kidney allograft status.

Cellular rejection after renal transplantation, in general, occurs as a result of an interaction between immunologic processes that maintain graft tolerance versus allograft rejection. A potential mechanism that triggers such processes might be through the activation of the innate immune response initiated during organ procurement and ischemia/reperfusion injury, contributing to delayed graft function or graft dysfunction. Our goal was to test the impact of molecular markers that have key roles in innate immunity such as cytokines, Toll-like receptors (TLRs), and allograft inflammatory factor-1 (AIF- 1) at early times after transplantation.

Characterization of chitosan films and effects on fibroblast cell attachment and proliferation.

Chitosan has been researched for implant and wound healing applications. However, there are inconsistencies in reports on the tissue and fibroblast responses to chitosan materials. These inconsistencies may be due to variations in chitosan material characteristics.

Velocity and strain-rate profiles in materials subjected to unlubricated sliding.

This Letter focuses on the plastic response of a material, treated as a fluid, when subjected to sliding interactions. The analysis couples momentum conservation with material flow laws to predict velocity and strain-rate profiles that develop during sliding. The profiles depend on the strain-rate sensitivity.

Outliers involving the Poly(A) effect among highly-expressed genes in microarrays.

Background: The Poly(A) effect is a cross-hybridization artifact in which poly(T)-containing molecules, which are produced by the reverse transcription of a poly(A)+ RNA mixture, bind promiscuously to the poly(A) stretches of the DNA in microarray spots. It is customary to attempt to block such hybridization by adding poly(A) to the hybridization solution. This note describes an experiment intended to evaluate circumstances under which the blocking procedure may not have been successful.

Teaching international nursing students: challenges and strategies.

Cross-cultural education presents many challenges and focuses attention on the significant differences in teaching and learning styles around the world. In 1995, the George Mason University College of Nursing and Health Science embarked on the Saudi-US University Project, an effort that brought these theoretical differences to life. The stark contrast between the Saudi Arabian and Western cultures provided administration, faculty, and students the opportunity to develop creative strategies to accommodate learning across cultures.

Downregulation of DNA topoisomerase I in old versus young human diploid fibroblasts.

DNA topoisomerase I (Topo I) is an enzyme that alters the superhelicity of DNA. It has been implicated in such critical cellular functions as transcription, DNA replication, and recombination. Roles for Topo I in DNA repair following DNA damage have also been studied extensively.

Effects of head-down bed rest on complex heart rate variability: response to LBNP testing.

Head-down bed rest is used to model physiological changes during spaceflight. We postulated that bed rest would decrease the degree of complex physiological heart rate variability. We analyzed continuous heart rate data from digitized Holter recordings in eight healthy female volunteers (age 28-34 yr) who underwent a 13-day 6 degree head-down bed rest study with serial lower body negative pressure (LBNP) trials.

Two-dimensional electrophoretic profile of human sperm membrane proteins.

The purpose of this study was to characterize highly enriched human spermatozoa membrane proteins by two-dimensional electrophoresis and computer image analysis. Sperm membrane proteins were extracted by detergent solubilization from three different preparations: 1) washed semen cells following centrifugation and three wash steps in Ham's F-10 medium (the standard sperm preparation, which is contaminated with seminal immature germ cells, white blood cells, and acellular material), 2) the motile sperm fraction following centrifugation of diluted semen cells through a Percoll density gradient to enrich (> 98%) the viable mature sperm population, and 3) sperm membrane vesicles isolated from Percoll-purified motile mature sperm by nitrogen cavitation followed by differential centrifugation. The two-dimensional gel profiles of extracts of washed semen cells and motile spermatozoa contained more than 600 protein spots between pH 4 and 7 and apparent molecular mass ranging from 7.

Increased walking variability in elderly persons with congestive heart failure.

Objectives: To determine the effects of congestive heart failure on a person's ability to walk at a steady pace while ambulating at a self-determined rate.

Setting: Beth Israel Hospital, Boston, a primary and tertiary teaching hospital, and a social activity center for elderly adults living in the community.

Participants: Eleven elderly subjects (aged 70-93 years) with well compensated congestive heart failure (NY Heart Association class I or II), seven elderly subjects (aged 70-79 years) without congestive heart failure, and 10 healthy young adult subjects (aged 20-30 years).

Conventional heart rate variability analysis of ambulatory electrocardiographic recordings fails to predict imminent ventricular fibrillation.

Objectives: The purpose of this report was to study heart rate variability in Holter recordings of patients who experienced ventricular fibrillation during the recording.

Background: Decreased heart rate variability is recognized as a long-term predictor of overall and arrhythmic death after myocardial infarction. It was therefore postulated that heart rate variability would be lowest when measured immediately before ventricular fibrillation.

bpshape wk4: a computer program that implements a physiological model for analyzing the shape of blood pressure waveforms.

We describe the theory and computer implementation of a newly-derived mathematical model for analyzing the shape of blood pressure waveforms. Input to the program consists of an ECG signal, plus a single continuous channel of peripheral blood pressure, which is often obtained invasively from an indwelling catheter during intensive-care monitoring or non-invasively from a tonometer. Output from the program includes a set of parameter estimates, made for every heart beat.

Cocaine effects on neonatal heart rate dynamics: preliminary findings and methodological problems.

Cocaine use by pregnant women has been reported to cause fetal and neonatal morbidity and mortality. We hypothesized that human neonates exposed to cocaine via maternal use during pregnancy might manifest changes in beat-to-beat heart rate variability, similar to those described in experimental animals. In this preliminary report, we present findings from the first systematic analysis of heart rate dynamics in a small group of (n = 5) neonates exposed in utero to cocaine compared to gestationally age matched controls (n = 6) without known drug exposure.

A new technique for simultaneous monitoring of electrocardiogram and walking cadence.

A new technique for simultaneously recording continuous electrocardiographic (ECG) data and walking step rate (cadence) is described. The ECG and gait signals are recorded on 2 channels of an ambulatory Holter monitor. Footfall is detected using ultrathin, force-sensitive foot switches and is frequency modulated.

Personal computer interface and software for the ZONAX microscope attachment controller.

We describe the hardware and software of a general-purpose interface that permits a personal computer (PC) running MS-DOS to control cytometric devices, e.g., a scanning stage, shutters, and focus motor attached to a microscope.

Nonlinear mechanics of the heart's swinging during pericardial effusion.

When excessive fluid accumulates in the pericardial space, the heart, suspended by the great vessels, is then free to swing as a pendulum. The swinging may occur at either the same frequency as the heart rate (1:1 oscillation) or at half the heart rate (2:1 oscillation), the latter frequency often arising during cardiac tamponade. We show that these two frequencies of oscillation may be explained by the nonlinearity of Newton's equation of motion as applied to the heart.

Note on the dispersion of generations among cells in senescing diploid fibroblast populations.

The cells in a cultured diploid fibroblast population have heterogeneous intermitotic times--even cells derived from the same mitosis may divide at different ages. This heterogeneity of inter-mitotic times results in asynchronous population growth and a dispersion of generations among members of the cell population. Because the appearance of non-dividing cells in middle-age populations has been attributed to the presence of lineages with more generations than average, we estimated the magnitude of the dispersion of cell generations as functions of the population doubling level and of the coefficient of variation of inter-mitotic times.

Nonlinear dynamics in sudden cardiac death syndrome: heartrate oscillations and bifurcations.

Patients at high risk of sudden cardiac death show evidence of nonlinear heartrate dynamics, including abrupt spectral changes (bifurcations) and sustained low frequency (.01-.04 Hz) oscillations in heartrate.

A novel motion detection method for improving the quality of two-dimensional echocardiographic images.

Two-dimensional echocardiographic pictures from elderly patients are often technically unsatisfactory. It may be helpful or even necessary to improve the signal-to-noise ratio of these images before interpreting them. A novel picture-averaging method for obtaining the improved image is described here.

Multiple-transition cell cycle models that exhibit transition probability kinetics.

Cell cycle models that allow multiple random transitions and asymmetric cell division may exhibit a property that has been used to support the transition probability model of the cell cycle: that the absolute value of the difference between sibling cell inter-mitotic times varies from one sibling pair to another and is described by an exponential statistical distribution. Three models that show this property are described, each of which postulates the existence of objects that are partitioned between daughter cells during cell division and whose number influences the duration of the subsequent cell cycle, e.g.