Hemorrhage induces an increase in serum TNF which is not associated with elevated levels of endotoxin

Although tumor necrosis factor (TNF) and interleukin 6 (IL 6) are purported to be important mediators of inflammatory responses following trauma, it is not known if the serum levels of these cytokines are altered by simple hemorrhage. The objective of this study therefore was to determine whether or not: 1) there is any elevation of TNF or IL 6, and 2) if endotoxin, an important upregulator of these cytokines, is also increased following hemorrhage. To study this, C3H/HeN mice were bled to, and maintained at a mean blood pressure of 35 mmHg for 60 min, and then resuscitated with their own shed blood and adequate fluid. Mice were sacrificed at 30 min into hemorrhage and at 2, 4 or 24 hr post-hemorrhage to obtain serum samples. IL 6 and TNF levels were measured using cytokine dependent cellular assays. Using a quantitative Limulus amebocyte lysate assay, endotoxin levels were determined. TNF levels were significantly elevated at 30 min into hemorrhage, remaining so at 2 hr after resuscitation, but absent by 4 hr. Although there was a trend toward elevated IL 6 levels at 2 hr following hemorrhage, which was sustained up to 24 hr, the values were not significantly different from sham controls. When compared to controls, no marked increase in endotoxin was seen at any time point during or following hemorrhage. These results indicate that hemorrhage, in the absence of significant tissue trauma, causes enhanced TNF release which is not the result of increased endotoxin.     

Hypertrophic Cardiomyopathy. An Electrophysiological Study

Recordings of the transmembrane action potential of the cardiac myofibril from a patient with hypertrophic obstructive cardiomyopathy showed that the repolarization time was appreciably prolonged and that the maximum rate of follow was grossly reduced. This electrical abnormality is compatible with the late and irregular activation of the ventricular muscle in the disease. Propranolol was found to produce a similar “quinidine-like” effect on the transmembrane actionpotential in both cardiomyopathic and control tissue.     

Single-Cell Analysis Reveals Early Manifestation of Cancerous Phenotype in Pre-Malignant Esophageal Cells

Cellular heterogeneity plays a pivotal role in a variety of functional processes in vivo including carcinogenesis. However, our knowledge about cell-to-cell diversity and how differences in individual cells manifest in alterations at the population level remains very limited mainly due to the lack of appropriate tools enabling studies at the single-cell level. We present a study on changes in cellular heterogeneity in the context of pre-malignant progression in response to hypoxic stress. Utilizing pre-malignant progression of Barrett’s esophagus (BE) as a disease model system we studied molecular mechanisms underlying the progression from metaplastic to dysplastic (pre-cancerous) stage. We used newly developed methods enabling measurements of cell-to-cell differences in copy numbers of mitochondrial DNA, expression levels of a set of mitochondrial and nuclear genes involved in hypoxia response pathways, and mitochondrial membrane potential. In contrast to bulk cell studies reported earlier, our study shows significant differences between metaplastic and dysplastic BE cells in both average values and single-cell parameter distributions of mtDNA copy numbers, mitochondrial function, and mRNA expression levels of studied genes. Based on single-cell data analysis, we propose that mitochondria may be one of the key factors in pre-malignant progression in BE.     

High-density small-volume gel loading directly from capillary tubes

A technique has been developed for high lane density loading of small-volume DNA samples in a horizontal agarose gel. This technique has been investigated with a simple hand-held tool that is made to couple to sample output from a new capillary-based sample automation system. The approach consists of piercing the gel with pressurized sample capillaries and relieving the pressure shortly before withdrawal. The pressurization prevents the capillary from aspirating the gel buffer and keeps the sample at the tip of the capillary, so that it may be sucked into the gel during withdrawal. This method is shown to be adequate for a wide range of DNA ladders and PCR-based screening. In addition to allowing smaller lanes and a higher lane density than is achievable with traditional well-forming techniques, it relaxes the need for well formation and the alignment of the sample loader with those wells, providing an easy, efficient means of loading agarose gels.     

Endothelial monocyte-activating polypeptide II causes NOS-dependent pulmonary artery vasodilation: a novel effect for a proinflammatory cytokine

Endothelial monocyte-activating polypeptide (EMAP) II is a novel proinflammatory cytokine that is released from apoptotic and hypoxic cells. The purpose of this study was to determine the effect of EMAP II on the pulmonary artery (PA) and to characterize its mechanism of action. To study this, isolated PA rings from adult male Sprague-Dawley rats were suspended on steel hooks connected to force transducers and immersed in 37 degrees C organ baths containing modified Krebs-Henseleit solution. After equilibration, force displacement of phenylephrine-preconstricted PA was measured in response to EMAP II. Experiments were performed in endothelium-intact rings, endothelium-denuded rings, and in the presence of the NOS inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME). Pulmonary artery rings were then subjected to quantitative PCR analysis for inducible NOS (iNOS) mRNA. EMAP II caused a maximal vasodilation of 251 +/- 30.7 mg in endothelium-intact PA. EMAP II caused no vasodilation in endothelium-denuded and l-NAME-treated PA (20 +/- 14.0 mg and 17.5 +/- 7.5 mg, respectively, P < 0.001 vs. endothelium intact). In addition to its vasoactive properties, EMAP II increased PA iNOS mRNA twofold compared with controls. These results demonstrate that 1) EMAP II causes PA vasodilation; 2) EMAP II-mediated PA vasodilation is endothelium dependent and NOS dependent; and 3) EMAP II upregulates iNOS mRNA expression in PA. This report constitutes the first demonstration of EMAP II's effects on the pulmonary artery, its mechanism of action, and represents the identification of the first proinflammatory cytokine to cause PA vasodilation.     

Stress-induced thermoprotection of neuromuscular transmission

Environmental stresses such as high temperature or low levelsof oxygen can lead to structural destabilization of cells, disruptionof cellular processes, and, in extreme cases, death. Previousexperience of sub-lethal stress can lead to protection duringa subsequent stress that may otherwise have been lethal. Synapsesare particularly vulnerable to extreme environmental conditionsand failure of function at this level may be the primary causeof organismal death. Prior heat shock induces enhanced thermotoleranceat neuromuscular junctions in the locust extensor tibiae muscleand in abdominal muscles of larval Drosophila. Synaptic thermoprotectionis associated with an increase in short-term plasticity at thesesynapses. Prior anoxic coma in locusts induces synaptic thermotolerancesuggesting that the same protective pathways are activated.It is well established that diverse forms of stress induce theupregulation of cellular chaperones (heat shock proteins; HSPs)that mediate acquired protection. The mechanisms underlyingHSP-mediated synaptic protection are currently unknown but evidenceis accumulating that stabilization of the cytoskeleton may playan important role.     

The aesthetic earlobe: classification of lobule ptosis on the basis of a survey of North American Caucasians

North American Caucasian male subjects (n = 59) and female subjects (n = 72) were surveyed, to investigate earlobe height preferences that could serve as guidelines for aesthetic earlobe surgical procedures and reconstructions. Subjects were asked to rank their preferences for variously shaped earlobes in life-size-scaled sketched male and female profiles. Earlobe heights were varied on the basis of previously established anatomical landmarks, including the intertragal notch, the most caudal anterior attachment of the earlobe to the cheek skin (the otobasion inferius), and the most caudal extension of the earlobe-free margin (the subaurale). While the intertragal notch-to-otobasion inferius distance (range, 5 to 20 mm) and otobasion inferius-to-subaurale distance (range, 0 to 20 mm) varied, all other facial and ear anthropometric measurements were held constant. Each of the rank orders for the female and male facial profiles completed by the female and male subjects demonstrated statistical significance, as determined by one-way analysis of variance analysis of ranks (p < 0.001 for all four groups). No difference was noted between the two sexes' rank orders for either sex (p > 0.05). Therefore, analysis of the combined male and female preferences for each sex was completed with one-way analysis of variance analysis of ranks (p < 0.001 and p < 0.001) and a post hoc Dunn's test, to delineate significant preference differences between subgroups with respect to the intertragal notch-to-otobasion inferius and otobasion inferius-to-subaurale distances. Both female and male earlobe intertragal notch-to-otobasion inferius distances were preferred at either 5, 10, or 15 mm, more so than at 20 mm (p < 0.05 for all female and male comparisons). Furthermore, both female and male earlobe otobasion inferius-to-subaurale distances were preferred, in descending order, at 5 mm > 10 mm > 0 mm > 15 mm > 20 mm (p < 0.05 for all female and male comparisons). On the basis of the findings of this survey, the first classification of earlobe ptosis (based on otobasion inferius-to-subaurale distances), as well as a criterion for earlobe pseudoptosis (intertragal notch-to-otobasion inferius distance of greater than 15 mm), is presented. These findings suggest a role for independent assessment of the lobule length with respect to its anteriorly attached cephalad component (intertragal notch-to-otobasion inferius distance) and its free-margin caudal component (otobasion inferius-to-subaurale distance).     

Heat shock prevents simulated ischemia-induced apoptosis in renal tubular cells via a PKC-dependent mechanism

Heat shock produces cellular tolerance to a variety of adverse conditions; however, the protective effect of heat shock on renal cell ischemic injury remains unclear. Protein kinase C (PKC) has been implicated in the signaling mechanisms of acute preconditioning, yet it remains unknown whether PKC mediates heat shock-induced delayed preconditioning in renal cells. To study this, renal tubular cells (LLC-PK1) were exposed to thermal stress (43 degrees C) for 1 h and heat shock protein (HSP) 72 induction was confirmed by Western blot analysis. Cells were subjected to simulated ischemia 24 h after thermal stress, and the effect of heat shock (delayed preconditioning) on ischemia-induced apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling) and B cell lymphoma 2 (Bcl(2)) expression (Western) was determined. Subsequently, the effect of PKC inhibition on HSP72 induction and heat stress-induced ischemic tolerance was evaluated. Thermal stress induced HSP72 production, increased Bcl(2) expression, and prevented simulated ischemia-induced renal tubular cell apoptosis. PKC inhibition abolished thermal induction of HSP72 and prevented heat stress-induced ischemic tolerance. These data demonstrate that thermal stress protects renal tubular cells from simulated ischemia-induced apoptosis through a PKC-dependent mechanism.     

Substitutions in the pheromone-responsive Gbeta protein of Saccharomyces cerevisiae confer a defect in recovery from pheromone treatment.

The pheromone-responsive Galpha protein of Saccharomyces cerevisiae, Gpa1p, stimulates an adaptive mechanism that downregulates the mating signal. In a genetic screen designed to identify signaling elements required for Gpa1p-mediated adaptation, a large collection of adaptive-defective (Adp-) mutants were recovered. Of the 49 mutants characterized thus far, approximately three-quarters exhibit a dominant defect in the negative regulation of the pheromone response. Eight of the dominant Adp- mutations showed tight linkage to the gene encoding the pheromone-responsive Gbeta, STE4. Sequence analysis of the STE4 locus in the relevant mutant strains revealed seven novel STE4 alleles, each of which was shown to disrupt proper regulation of the pheromone response. Although the STE4 mutations had only minor effects on basal mating pathway activity, the mutant forms of Gbeta dramatically affected the ability of the cell to turn off the mating response after exposure to pheromone. Moreover, the signaling activity of the aberrant Gbetagamma subunits was suppressed by G322E, a mutant form of Gpa1p that blocks the pheromone response by sequestering Gbetagamma, but not by E364K, a hyperadaptive form of Gpa1p. On the basis of these observations, we propose that Gpa1p-mediated adaptation involves the binding of an unknown negative regulator to Gbetagamma.