Computational models of cardiovascular function for analysis of post-flight orthostatic intolerance.

The work presented in this paper is part of an ongoing effort to use mathematical models to investigate the effects of microgravity on the cardiovascular system. In particular, a thirteen compartment lumped parameter representation of the cardiovascular system is used to simulate some of the current hypotheses concerning the mechanism of post-flight orthostatic intolerance. Simulations are compared to astronaut stand test data pre - and post-flight in an effort to quantitatively evaluate alternative hypotheses.

cgh-1, a conserved predicted RNA helicase required for gametogenesis and protection from physiological germline apoptosis in C. elegans.

A high frequency of apoptosis is a conserved hallmark of oocyte development. In C. elegans, about half of all developing oocytes are normally killed by a physiological germline-specific apoptosis pathway, apparently so that they donate cytoplasm to the survivors.

Microdermabrasion: a clinical and histopathologic study.

Background: Microdermabrasion is a widely performed skin rejuvenation procedure. Few studies have examined its efficacy.

Objective: To evaluate the clinical and histopathologic effects of microdermabrasion.

Transcriptional repression by the Caenorhabditis elegans germ-line protein PIE-1.

In the early Caenorhabditis elegans embryo, maternally expressed PIE-1 protein is required in germ-line blastomeres to inhibit somatic differentiation, maintain an absence of mRNA transcription, and block phosphorylation of the RNA polymerase II large subunit (Pol II) carboxy-terminal domain (CTD). We have determined that PIE-1 can function as a transcriptional repressor in cell culture assays. By fusing PIE-1 sequences to the yeast GAL4 DNA-binding domain, we have identified a PIE-1 repression domain that appears to inhibit the transcriptional machinery directly.

Binding of the winged-helix transcription factor HNF3 to a linker histone site on the nucleosome.

The transcription factor HNF3 and linker histones H1 and H5 possess winged-helix DNA-binding domains, yet HNF3 and other fork head-related proteins activate genes during development whereas linker histones compact DNA in chromatin and repress gene expression. We compared how the two classes of factors interact with chromatin templates and found that HNF3 binds DNA at the side of nucleosome cores, similarly to what has been reported for linker histone. A nucleosome structural binding site for HNF3 is occupied at the albumin transcriptional enhancer in active and potentially active chromatin, but not in inactive chromatin in vivo.

Nucleosome positioning by the winged helix transcription factor HNF3.

Nucleosome positioning at genetic regulatory sequences is not well understood. The transcriptional enhancer of the mouse serum albumin gene is active in liver, where regulatory factors occupy their target sites on three nucleosome-like particles designated N1, N2, and N3. The winged helix transcription factor HNF3 binds to two sites near the center of the N1 particle.

Short-pulse carbon dioxide laser resurfacing in the treatment of rhytides and scars. A clinical and histopathological study.

Background: Previous studies have shown the efficacy of short-pulse carbon dioxide (CO2) lasers in the treatment of rhytides and scars. To date, there have been few studies examining the histological aspects of these treatments.

Objective: The purpose of this study was to perform a prospective clinical and histopathological study of CO2 laser resurfacing for improvement of facial rhytides and scars.

Numerical analysis of three-dimensional Björk-Shiley valvular flow in an aorta.

Laminar vortical flow around a fully opened Björk-Shiley valve in an aorta is obtained by solving the three-dimensional incompressible Navier-Stokes equations. Used is a noniterative implicit finite-element Navier-Stokes code developed by the authors, which makes use of the well-known finite difference algorithm PISO. The code utilizes segregated formulation and efficient iterative matrix solvers such as PCGS and ICCG.

Development of thymic carcinoma in transgenic mice expressing SV40 T antigen.

We produced transgenic mice using SV40 Tag gene under the control of its own enhancer and promoter. Three transgenic lines (SNU-SVT125, 127, 248) consistently developed thymic carcinoma as well as choroid plexus carcinoma and dysplastic renal tubule. In SNU-SVT248 line, SV40 Tag transgene was expressed at thymus, spleen and kidney.

A comparison of once-daily and 8-hour gentamicin dosing in the treatment of postpartum endometritis.

Objective: To evaluate whether once-daily gentamicin dosing is as effective as the traditional 8-hour regimen for the treatment of postpartum endometritis.

Methods: Postpartum women with endometritis were randomized to receive gentamicin 5 mg/kg as a single daily dose or 1.75 mg/kg every 8 hours.

T cell lymphoma in transgenic mice expressing the human Hsp70 gene.

In the course of studying the role of hsp70 in the differentiation of pancreatic beta cells, transgenic founder mice were generated with the human hsp70 gene fused to the human insulin gene promoter. One resulted in a transgenic line that consistently developed diabetes mellitus, but unexpectedly three other independent transgenic founders developed generalized malignant lymphoma within 10 months after birth. Immunochemical and RT-PCR analyses revealed that the transgene was expressed in the lymphoma cells.

Allosteric interaction of a herpes simplex viral thymidine kinase with host DNA polymerase alpha in mouse LP1-1 cells.

A DNA polymerase alpha-associated multienzyme complex isolated from mouse LP1-1 cells transfected with the thymidine kinase gene of herpes simplex virus type I (1) showed activities of DNA polymerase alpha, topoisomerase II, and thymidine kinase (TK) in the complex. TK antiserum recognized a 43 kDa polypeptide only in the fraction of the multienzyme complex prepared from the LP1-1 cells but not that from L-M(TK-) cells. In permeabilized cells, hydroxyurea did not show any inhibitory effect on either DNA polymerase or TK, whereas aphidicolin, novobiocin, and TK antiserum inhibited both enzymes.

An active tissue-specific enhancer and bound transcription factors existing in a precisely positioned nucleosomal array.

Nucleosomes positioned over promoters are usually inhibitory to protein binding and activity. We analyzed at the nucleotide level of resolution the nucleosomal organization of a distal, liver-specific enhancer in various mouse tissues and found that the enhancer exists in an array of three precisely positioned nucleosomes only in liver chromatin, where the enhancer is active. In vivo footprinting reveals that essential transcription factor-binding sites are occupied on apparent nucleosome surfaces, in one case leading to a perturbed nucleosomal structure.

Axial and peripheral bone density and nutrient intakes of postmenopausal vegetarian and omnivorous women.

The study investigated whether differences exist between postmenopausal Caucasian vegetarian and omnivorous women regarding trabecular and cortical bone density measured with single- and dual-photon absorptiometry. Anthropometric measurements, blood and urine samples, and food intakes of the twenty-eight matched pairs were also compared. The Wilcoxon signed-rank test indicated no significant differences in bone measurements between vegetarians and omnivores at any sites except the skull.