A hypothesis for reactivation of pulmonary tuberculosis: How thoracic wall shape affects the epidemiology of tuberculosis

This study was aimed at determining the cause for the high incidence of tuberculosis (TB) reactivation occurring in males with a low body mass index (BMI). Current thinking about pulmonary TB describes infection in the lung apex resulting in cavitation after reactivation. A different hypothesis is put forward for TB infection, suggesting that this occurs in subclinical apical cavities caused by increased pleural stress due to a low BMI body habitus. A finite element analysis (FEA) model of a lung was constructed including indentations for the first rib guided by paramedian sagittal CT reconstructions, and simulations were conducted with varying antero‐posterior (AP) diameters to mimic chests with a different thoracic index (ratio of AP to the transverse chest diameters). A Pubmed search was conducted about gender and thoracic index, and the effects of BMI on TB. FEA modeling revealed a tenfold increase in stress levels at the lung apex in low BMI chests, and a four‐fold increase with a low thoracic index, r² = 0.9748 P < 0.001. Low thoracic index was related to BMI, P = 0.001. The mean thoracic index was statistically significantly lower in males, P = 0.001, and increased with age in both genders. This article is the first to suggest a possible mechanism linking pulmonary TB reactivation to low BMI due to the flattened thoracic wall shape of young male adults. The low thoracic index in young males may promote TB reactivation due to tissue destruction in the lung apex from high pleural stress levels. Clin. Anat. 28:614–620, 2015. © 2015 Wiley Periodicals, Inc.     

In vivo Intracellular Recording of Neurons in the Supraoptic Nucleus of the Rat Hypothalamus

Intracellular recordings were made from cells in the hypothalamic supraoptic nucleus in the urethane-anaesthetized male rat using the ventral surgical approach. Impalements lasted from 5 min to 1 h and recorded cells had an input resistance of 55 to 170 megohms. Spikes of over 50 mV were recorded from 14 cells which could be antidromically activated by stimulation of the neural stalk. The spikes showed a hyperpolarizing afterpotential and the broadening characteristic of rapidly firing magnocellular neurons, which recovered rapidly (<200 ms). When depolarized, the cells showed evidence of a transient potassium current. Recurrent synaptic coupling between the recorded cell and adjacent cells would be expected to alter the hyperpolarizing afterpotential of an antidromic spike as compared with a spontaneous spike; no perceptible difference in the waveforms of the different types of spike could be detected in 11 spontaneously active cells. Application of just subthreshold stimuli to the neural stalk did not evoke depolarizing or hyperpolarizing potentials. Suprathreshold shocks to the neural stalk, when the antidromic spike was prevented by collision, also had no discernible effect on membrane potential. Thus intracellular recordings from magnocellular neurons in vivo revealed electrophysiological properties similar to those seen in vitro. No evidence for synaptic interconnection between magnocellular neurons was found in male rats.     

The Usefulness of Magnetic Resonance Imaging in the Diagnosis of Anterolateral Impingement of the Ankle

The purpose of this study is to assess the sensitivity and specificity of magnetic resonance imaging (MRI) in the diagnosis of anterolateral impingement of the ankle and to assess the most helpful sequence in making the diagnosis. Twenty-four patients who had undergone ankle arthroscopy were chosen. Twelve patients had arthroscopically documented anterolateral impingement, and 12 patients with no impingement on arthroscopy served as controls. Two musculoskeletal radiologists and an orthopedic surgeon, blinded to the operative diagnosis, retrospectively reviewed selective MRI images in the sagittal, axial, and coronal planes. The sensitivities and specificities were calculated for all 3 reviewers. The Kendall coefficient of concordance was calculated for overall agreement among reviewers. Sensitivities varied from 0.75 to 0.83, whereas specificities varied from 0.75 to 1.00. Using the Fisher exact test of contingency, the sensitivities and specificities showed that all reviewers' interpretations were statistically significant with P = .039, .001, and .012, respectively. The axial images were felt to be most helpful in making the diagnosis. The physicians felt that the sagittal images were helpful in 67%, 83%, and 100%, respectively. MRI is a useful tool that can aid the clinician in the diagnosis of anterolateral impingement of the ankle. T1 sagittal images demonstrating displacement of the normal fat signal anterior to the fibula by scar can be useful and help to confirm the diagnosis.     

Responses to ethanol challenge in long- and short-sleep mice prenatally exposed to alcohol

Individual sensitivity to alcohol may influence the severity of functional deficits due to prenatal alcohol exposure. To examine this hypothesis, Long-Sleep (LS) and Short-Sleep (SS) mice, selectively bred for differences in ethanol-induced narcosis, were intubated with either 2.9 g/kg ethanol (E) or an isocaloric amount of sucrose (S) twice per day on days 7 through 15 of pregnancy. An untreated control group (C) was maintained for each line. Offspring were fostered to lactating Rockland-Swiss mice at birth. Males and females from each litter were challenged with an acute dose of ethanol (3.8 g/kg) at 30 days of age. Measures of sleep time duration, waking blood ethanol concentrations (BEC), rectal temperatures, heart rate, and ethanol clearance were obtained to examine whether the acute effects of ethanol are altered by prenatal alcohol exposure. Prenatal alcohol exposure did not differentially affect responses to ethanol challenge within either genotype. Ethanol-induced hypothermia, heart-rate depression, and sleep time did differ between genotypes, with LS more affected than SS mice. Ethanol clearance rates were faster for SS than LS mice. These results suggest postnatal pharmacological responses to acute ethanol challenge are not altered by prenatal alcohol exposure in LS and SS mice. Prenatal alcohol-exposed offspring of both mouse genotypes showed lower average heart rate responses than controls, suggesting this measure may be a sensitive indicator of prenatal alcohol effects in mice.     

Calmodulin stimulates the degradation of brain spectrin by calpain

Brain spectrin has been shown to be a preferential substrate of calcium-dependent proteases (Baudry, Bundman, Smith, and Lynch: Science 212:937-938, 1981) and a major calmodulin-binding protein (Kakiuchi, Sobue, and Fujita: FEBS Lett. 132:144-148, 1981). Since calmodulin, spectrin, and a proteolytically derived spectrin fragment are all components of isolated postsynaptic density preparations (Grab, Berzins, Cohen, and Siekevitz: J. Biol. Chem. 254:8690-8696, 1979; Carlin, Bartelt, and Siekevitz: J. Cell Biol. 96:443-448, 1983), we investigated the functional role of calmodulin binding to brain spectrin with respect to its susceptibility to digestion by proteases. We report that calmodulin's interaction with brain spectrin results in a marked acceleration of the rate of spectrin degradation by calcium-dependent proteases (calpains I and II), but not by chymotrypsin. The cleavage of erythrocyte spectrin (which lacks a high-affinity calmodulin binding site) by calpain I is unaffected by the presence of calmodulin. The stimulatory effect of calmodulin is blocked by trifluoperazine, a calmodulin antagonist, which by itself does not modify brain spectrin proteolysis by calcium-dependent proteases. These results suggest a novel role for calmodulin in neuronal function--namely, a synergistic interaction with calcium-dependent proteases in the regulation of cytoskeletal integrity.     

142Effects of Low‐Frequency Ultrasound Applied In Vitro to Highly Antibiotic‐Resistant Acinetobacter Isolates Recovered From Soldiers Returning From Iraq

Abstract  Brooke Army Medical Center isolated 25 highly antibiotic‐resistant Acinetobacter ssp . (primarily A. baumannii ) from wounded soldiers returning from Iraq. Concern about effective treatment of these organisms led our institution to begin investigating low‐frequency ultrasound (LFU) as a method of increasing the effectiveness of antibiotics on A.baumannii in wound management. Studies have suggested that LFU applied in conjunction with antibiotics may increase their overall effectiveness. We hypothesize that combining antibiotics with LFU may be an effective method of wound management and that this combination may be synergistic in its overall effect. In this initial work, we wanted to determine if sonocation would have an effect on our organism of interest, A. baumannii . We selected several organisms, both gram positive and gram negative, that have been shown to be killed by sonocation ( E. coli, S. aureus , and S. pyogenes ) and added three highly resistant A. baumannii isolates. Bacterial death was measured by both colony counts after 24 hours of growth and acridine orange staining using a standard protocol.
Colony counts were significantly reduced by sonocation. Furthermore, A.'baumannii colony counts were also greatly reduced by sonocation. Actual cell destruction was also visualized using acridine orange staining. Our data support the assertion that sonocation has an antibacterial effect on some bacteria, including A. baumannii . Our next step is to add antimicrobial agents and determine if their effectiveness can be increased by sonocation.     

Comparison of three intracellular markers for combined electrophysiological, morphological and immunohistochemical analyses.

Hypothalamic paraventricular and supraoptic neurons were recorded intracellularly in coronal slices and injected with Lucifer yellow, ethidium bromide or biocytin. Electrical properties, morphological staining and neurophysin immunohistochemistry were compared among the 3 markers. Lucifer yellow electrodes had a high resistance and frequently blocked during experiments. Neurons recorded with Lucifer yellow electrodes had low input resistances and low-amplitude, broad spikes. Lucifer yellow labeling in whole mount was highly fluorescent, revealing distal dendrites and axons. Of cells injected with Lucifer yellow, 64% were recovered but were faint after immunohistochemical processing. Recordings with ethidium bromide electrodes were similar to controls, although electrode blockage sometimes occurred. Only somata and proximal dendrites of ethidium bromide-filled neurons were visible in whole-mount. Forty percent of cells injected with ethidium bromide were recovered after immunohistochemical processing; these were invariably faint. Recordings with biocytin-filled electrodes were similar to control recordings. Biocytin-filled, HRP-labeled cells showed distal dendrites and often dendritic spines and axons in 50-75-microns sections. Seventy percent of biocytin-injected cells labeled with fluorescent markers were recovered and remained strongly labeled after immunohistochemical processing. Biocytin had the best electrical and staining properties for combined electrophysiological and anatomical studies.     

Induction of islet cytodifferentiation by fetal mesenchyme in adult pancreatic ductal epithelium.

Recombinant tissue consisting of adult ductal epithelium isolated from pancreas and fetal mesenchyme was transplanted subcutaneously in the inguinal region of nude mice or epididymal fat pads of rats with a tissue chamber device for short-term (8-day) or long-term (6- to 12-wk) duration. We found that recombinant tissue underwent morphogenesis and cytodifferentiation, thereby forming islets that contained cells immunocytochemically positive for insulin and glucagon. Islet cytodifferentiation occurred in approximately 20% of the recombinants. In recombinants that developed into islets, the tissue was always in close association with an extracellular matrix, nerves, and blood vessels. Controls consisting of mesenchyme alone or duct epithelium alone showed no evidence of morphogenesis of cytodifferentiation. Pancreatic rudiments were also implanted to serve as positive controls. This is the first demonstration of islet cytodifferentiation from adult duct epithelium.     

Association between inflammation and epithelial damage-restitution processes in allergic airways in vivo

Background Associations between allergen challenge-induced sites of epithelial damage and the distribution of leucocytes and extravasated plasma remain unexplored. Objective To study neutrophils, eosinophils, and fibrinogen at allergen challenge-induced patchy epithelial damage-restitution sites in guinea-pig trachea. Methods After local challenge tracheal tissue (cryo sections and whole-mounts) and lumen (selective tracheal lavage) were examined at 1, 5, and 24 h. Eosinophils, neutrophils and fibrinogen were identified by histochemistry. Results Neutrophils increased markedly in tracheal lavage fluids and in tissue and were strongly associated with the challenge-induced epithelial craters of damage-restitution. At 1 and 24 h eosinophils were increased in the tracheal lumen whereas the surrounding tissue displayed a reversed pattern. Gels rich in fibrinogen, neutrophils, and eosinophils were present in epithelial crater areas, protruding into the lumen. Clusters of free eosinophil granules, Cfegs, released through lysis of eosinophils, and neutrophils with long cytoplasmatic protrusions abounded in these crater areas. Conclusions The present findings provide important new insights into allergic airways where sites of epithelial damage-restitution processes emerge as the major loci for eosinophil, neutrophil, and plasma protein activities, the latter likely causing leukocyte adhesion and activation in vivo. The disttibution of eosinophils in this study suggests roles of these cells both in airway mucosa and in regional lymph nodes. Based on the present study we also propose that lysis of eosinophils and Cfegs generation are a major paradigm for activation of these cells in vivo.     

Genotype-dependent effects of GABAergic agents on sedative properties of ethanol

Two lines of mice, selectively bred for differential sensitivity to the soporific effects of ethanol (ETOH), were administered GABAergic drugs in an effort to evaluate a role for GABA in ETOH sensitivity. ETOH sensitive Long-Sleep mice (LS) showed potentiated ETOH sedation when administered bicuculline, muscimol and aminooxyacetic acid (AOAA). ETOH-insensitive SS mice exhibited reduced ETOH sedation in the presence of the antagonists, bicuculline and picrotoxin, and potentiated sedation in the presence of muscimol and AOAA. These changes in narcosis duration were interpreted as central effects, since blood ethanol levels at waking from ETOH sedation varied with GABAergic drug treatment. Picrotoxin antagonized pentobarbital-induced nacrosis in both lines, but to a greater extent in SS mice. These and other experiments with a genetically heterogeneous stock suggest GABA involvement in genotype-dependent ETOH sensitivity, but do not support a simple role of GABA receptor involvement.