Citations

Lower-limb ischemia is a major health problem. Because of the absence of effective treatment in the advanced stages of the disease, amputation is undertaken to alleviate unbearable symptoms. Novel therapeutic approaches include the intramuscular use of autologous bone marrow cells (BMCs). Because tissue ischemia is associated with an overwhelming generation of oxygen radicals and negative effects due to perturbed shear-stress, metabolic intervention with antioxidants and l -arginine could potentially induce beneficial effects beyond those achieved by BMCs. The protective effect of autologous BMCs and vascular protection by metabolic cotreatment (1.0% vitamin E added to the chow and 0.05% vitamin C and 6% l -arginine added to the drinking water) were examined in ischemia-induced angiogenesis in the mouse hindlimb, a model of extensive acute peripheral arterial occlusion. i.v. BMC therapy improved blood flow and increased capillary densities and expression of Ki-67, a proliferation-associated protein. This beneficial effect was amplified by metabolic cotreatment, an intervention inducing vascular protection, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress, and macrophage activation. Therefore, although a cautious approach is mandatory when experimental findings are extended to human diseases, autologous BMCs together with metabolic intervention could be an effective clinical treatment for peripheral arterial disease.

Pulse pressure, the difference between systolic and diastolic blood pressure, is an independent risk factor for cardiovascular disease. Increased pulse pressure reflects reduced compliance of arteries and is a marker of atherosclerosis. To locate genes that affect pulse pressure, a genome-wide linkage scan for quantitative trait loci influencing pulse pressure was performed using variance components methods as implemented in sequential oligogenic linkage analysis routines. The analysis sample included 10 798 participants in 3320 families who were recruited as part of the Family Blood Pressure Program and were phenotyped with an oscillometric blood pressure measurement device using a consistent protocol across centers. Pulse pressure was adjusted for the effects of sex, age, age 2 , age-by-sex interaction, age 2 -by-sex interaction, body mass index, and field center to remove sources of variation other than the genetic effects related to pulse pressure. Significant linkage was observed on chromosome 18 (logarithm of odds [LOD]=3.2) in a combined racial sample, chromosome 20 (LOD=4.4), and 17 (LOD=3.6) in Hispanics, chromosome 21 (LOD=4.3) in whites, chromosome 19 (LOD=3.1) in a combined sample of blacks and whites, and chromosome 7 (logarithm of odds [LOD]=3.1) in blacks from the GenNet Network. Our genome scan shows significant evidence for linkage for pulse pressure in multiple areas of the genome, supporting previous published linkage studies. The identification of these loci for pulse pressure and the apparent congruence with other blood pressure phenotypes provide increased support that these regions contain genes influencing blood pressure phenotypes.

Abstract Deletion of phenylalanine 508 (ΔF508) accounts for nearly 70% of all mutations that occur in the cystic fibrosis transmembrane conductance regulator (CFTR). The ΔF508 mutation is a class II processing mutation that results in very little or no mature CFTR protein reaching the apical membrane and thus no cAMP-mediated Cl− conductance. Therapeutic strategies have been developed to enhance processing of the defective ΔF508 CFTR molecule so that a functional cAMP-regulated Cl− channel targets to the apical membrane. Sarcoplasmic/endoplasmic reticulum calcium (SERCA) inhibitors, curcumin and thapsigargin, have been reported to effectively correct the CF ion transport defects observed in the ΔF508 CF mice. We investigated the effect of these compounds in human airway epithelial cells to determine if they could induce ΔF508 CFTR maturation, and Cl− secretion. We also used Baby Hamster Kidney cells, heterologously expressing ΔF508 CFTR, to determine if SERCA inhibitors could interfere with the interaction between calnexin and CFTR and thereby correct the ΔF508 CFTR misfolding defect. Finally, at the whole animal level, we tested the ability of curcumin and thapsigargin to (1) induce Cl− secretion and reduce hyperabsorption of Na+ in the nasal epithelia of the ΔF508 mouse in vivo, and (2) induce Cl− secretion in intestine (jejunum and distal colon) and the gallbladder of the ΔF508 CF mouse. We conclude that curcumin and thapsigargin failed to induce maturation of ΔF508 CFTR, or induce Cl− secretion, as measured by biochemical and electrophysiologic techniques in a variety of model systems ranging from cultured cells to in vivo studies.

Canine blood was diluted with isotonic Rous-Turner solution at pH 5.8 or at 7.0. The suspended erythrocytes were exposed to ultrasonic energy at 495 kc/sec with cavitation either occurring or being suppressed by excess pressure. The same power was applied to the transducer whether or not cavitation was occurring. The rupture of the cells was measured spectrophotometrically. In addition, the osmotic fragility of the exposed cells was compared with that of control cells. The results were analyzed and graphed, using an IBM-1620 computer. These studies indicated that (1) canine erythrocytes can be ruptured in the absence of cavitation, albeit more slowly; (2) mechanical strength as determined ultrasonically is not simply related to osmotic fragility; (3) the changes of osmotic fragility after ultrasonic treatment were different from those after heating; (4) the destruction not due to cavitation occurred at intensities between those used for surgery and those used for physical therapy. [This work, performed with the technical assistance of N. Nolder, A. Hildestad, and L. C. Gatewood, was aided by National Institutes of Health grants GM 08299-02 and FR-00007.]

A number of recently developed and promising approaches to antitumoral immunotherapy are being investigated as potential treatments for advanced prostate cancer. These approaches largely revolve around strategies to increase antigen-specific T-cell activation against prostate tumors as well as precise manipulations of critical co-regulatory receptors that help to maintain and prolong the activity of antigen-presenting cells and T cells that are capable of mediating tumor regression. Herein, we describe the experience with the most recent and promising approaches pertaining to prostate cancer immunotherapy. Additionally, we discuss the mechanistic basis for these approaches as well as current limitations that must still be addressed in order to propel immunotherapy into the forefront of prostate cancer treatment.

Sp1 is one of the best characterized transcriptional activators. The biological importance of Sp1 is underscored by the fact that several hundreds of genes are thought to be regulated by this protein. However, during the last 5 years, a more extended family of Sp1-like transcription factors has been identified and characterized by the presence of a conserved DNA-binding domain comprising three Krüppel-like zinc fingers. Each distinct family member differs in its ability to regulate transcription, and, as a consequence, to influence cellular processes. Specific activation and repression domains located within the N-terminal regions of these proteins are responsible for these differences by facilitating interactions with various co-activators and co-repressors. The present review primarily focuses on discussing the structural, biochemical and biological functions of the repressor members of this family of transcription factors. The existence of these transcriptional repressors provides a tightly regulated mechanism for silencing a large number of genes that are already known to be activated by Sp1.

Abstract Background: Aging, body composition, and sex steroids jointly determine GH production. However, the actions of any given factor are confounded by the effects of the other two. Hypothesis: Age and abdominal visceral fat (AVF) mass govern GH secretion via individually distinctive mechanisms, which can be unmasked by short-term sex steroid deprivation. Design/Subjects: In a university setting, healthy pre- and postmenopausal volunteers underwent GnRH agonist-induced down-regulation for 6 wk to deplete ovarian sex steroids. GH secretion was evaluated by frequent blood sampling, saline vs. dual secretagogue infusions, an irregularity statistic, variable waveform deconvolution analysis, and a simplified feedback model. Computerized tomography was used to estimate AVF mass. Outcomes/Measures: In the sex steroid-deficient milieu, postmenopausal compared with premenopausal women exhibited 1) lower concentrations of IGF-I (P = 0.028) and GH (P < 0.05); 2) reduced pulsatile, but elevated basal, GH secretion (P < 0.05); 3) more irregular GH patterns (P = 0.027); 4) an attenuated GH response to simultaneous GHRH/GH-releasing peptide-2 stimulation (P < 0.01); and 5) more rapid onset of GH release within secretory bursts (P < 0.01). In contrast, AVF negatively forecast GH responses to l-arginine/GH-releasing peptide-2 (r2 = 0.45; P < 0.001) and l-arginine/GHRH (r2 = 0.57; P = 0.007). From these marked contrasts, model-based analyses predicted distinguishable mechanisms by which aging and AVF alter pulsatile GH production. Conclusion: Under limited confounding by sex steroids, age and body composition modulate GH secretion via highly selective peptidyl pathways in healthy women.

The goal of “Practice Abstracts” is to present interesting, topical, and novel applications of operations research methodology to a wide range of industrial applications. “Practice Abstracts” are intended to provide Interfaces readers with short (2–4 page) descriptions of the most relevant aspects of operations research-based projects, in a form that is accessible to academics and practitioners in other organizations. Contributions should be sent for evaluation to the editor of “Practice Abstracts,” Brian T. Denton, Division of Health Care Policy and Research, Pavilion 3, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, denton.brian@mayo.edu.