Cardioprotective effects of exogenous and endogenous hydrocortisone in the rabbit model of ischemia-reperfusion Efectos cardioprotectores de la hidrocortisona exógena y endógena en el modelo isquemia-reperfusión de conejo

Reducing the infarct size in acute myocardial infarction is one of the most important goals driving new drug research and development. During the last two decades, many clinical studies have found cardioprotective effects of corticosteroids, but their exact role in ischemic preconditioning remains questionable. The aim of the present study was to determine the protective effects of hydrocortisone sodium succinate on myocardial preconditioning in rabbit hearts. Twenty-four male New Zealand rabbits were divided randomly & equally in four groups: 1) control, 2) Infarct, 3) Ischemic preconditioning (IP) and 4) Hydrocortisone (HYD). The HYD group received 50mg/kg Hydrocortisone 45min before major ischemia. Serum levels of cardiac troponin-T(cTNT) and cortisole were measured before and after the protocols. Triphenyl-tetrazolium chloride staining was used to determine the infarcted area. In the present study, exogenous hydrocortisone decreased infarct size by 53 in comparison to the infarct group. Serum level of cortisole was increased in the IP and HYD groups, and was significant in the HYD group (p0.01). In conclusion, we showed that hydrocortisone has cardioprotective effects when injected before the onset of myocardial infarction. In addition, we have proposed for the first time that endogenous hydrocortisone may play a role in ischemic preconditioning phenomena

Morphometric evidences for regional variation in potential of neural plasticity

The neural plasticity showing the ability of nervous system to change its structure and function is a well-documented fact. However regional variation within a CNS structure to undergo plastic changes has been shown by limited studies. Along medial-lateral sequences of parasagittal sections, the molecular layer thickness of primary fissure borderlands in rat cerebellar left hemisphere was studied to assess the regional difference in plasticibility. Despite the homogeneity of cerebellar histology, this study showed that there is a significant interlobular difference between ML thicknesses of Prf borderlands. In addition, it revealed that the thickness alters in a significant trend within each borderland. The quantitative heterogeneity of cerebellar architecture such as variation of cortical thickness may provide some evidences to show that different regions of a homogenous cortex, even two adjacent borderlands and areas within them, can have different potentials for plasticity. © 2006 Sociedad Chilena de Anatomía

Gaucher disease: A 10 year old girl with anemia and huge spelenomegaly (a case report)

Gaucher's disease is a rare lipid storage disorder, affecting one in 40,000-200,000 people and results from a genetic deficiency of the enzyme glucocerebrosidase (glucosylceramidase). We report a 10-year old Iranian girl with chief complaint of anemia from 8 years ago, managed for iron deficiency anemia. The patient had hepatomegaly associated with huge splenomegaly which was confirmed by sonography. No skeletal disorder was found. Bone marrow aspiration revealed typical Gaucher cells. Low level of β-glucocerebrosidase enzyme activity confirmed the Gaucher disease. The patient is now under treatment with CEREZIME, a recombinant DNA modified form of glucocerebrosidase with good condition. © 2008 Asian Network for Scientific Information

Can formaldehyde exposure induce histopathologic and morphometric changes on rat kidney? [¿la exposición al formaldehído puede inducir cambios histopatológicos y morfométricos sobre el riñón de rata?]

Formaldehyde is used traditionally for fixing the cadaver, and vaporized during dissection and practical studying on cadaver. This study was designed to determine the histopathologic and morphometric changes of rat kidney while all of the experiments were exposed to formaldehyde for 18 weeks. 28 male albino Wistar rats were divided into the following three experimental groups (E1: 2hrs/d, 2d/w; E2: 2hrs/d, 4d/w; E3: 4hrs/d, 4d/w) and one control group (C). when the exposure period was expired the animals were anaesthetized with chloroform. After cervical dislocation, the abdomen was dissected and the kidneys were taken. The kidney specimens were sectioned and stained with Haematoxylin and Eosin technique for histologic and morphometric study. Data were obtained from an Olympus light microscope and the analyzed with spss (version 11.5) and ANOVA test. In all histopathology sections of groups E1, E2 and E3, these similar changes were seen: mild glumerolar congestion, focal congestion, and vacuolar degeneration of tubular cells. There were no evidences of inflammatory cells infiltration or fibrotic changes of interstitial tissue. Only mild, non-specific congestion was seen in cortical vessels. Also there were not any abnormalities in the staining of nucleus and cytoplasm. According to Morphometric study, Mean ±SD of glomerulus's area in control, E1, E2 and E3 group were 10802.66±1038.18, 10759.50±1971.88, 10434.73±1763.76 and 10077.64±2068.78 micrometer, respectively. Mean ±SD inner proximal tubule diameter in control, E1, E2 and E3 group were 16.16±2.49, 16.92±2.90, 16.31±2.79 and15.66±4.11 μm, respectively. Mean ±SD of inner distal tubule diameter in control, E1, E2 and E3 group were 15.96±4.47, 16.20±1.66, 16.96±1.63 and17.45±3.26 μm, respectively. These differences were not significant between cases and control. This study showed that formaldehyde inhalation in 1.5 ppm can not make specific Histopathologic and Morphometric changes in rat kidney

Efficient and optimized identification of generalized Maxwell viscoelastic relaxation spectra

Viscoelastic relaxation spectra are essential for predicting and interpreting the mechanical responses of materials and structures. For biological tissues, these spectra must usually be estimated from viscoelastic relaxation tests. Interpreting viscoelastic relaxation tests is challenging because the inverse problem is expensive computationally. We present here an efficient algorithm that enables rapid identification of viscoelastic relaxation spectra. The algorithm was tested against trial data to characterize its robustness and identify its limitations and strengths. The algorithm was then applied to identify the viscoelastic response of reconstituted collagen, revealing an extensive distribution of viscoelastic time constants. © 2015 Elsevier Ltd

Formaldehyde exposure induces histopathological and morphometric changes in the rat testis

Formaldehyde is a chemical which is traditionally used for fixing cadavers and routine histopathology techniques. It is vaponsed during the dissection and practical study of a cadaver. Previous studies have shown that this vapour may cause clinical symptoms such as throat, eye, skin and nasal irritation. This study was designed to determine the histopathology and morphometrics of the rat testis when all the experimental animals were exposed to formaldehyde for 18 weeks. The study was performed in 2004 on 28 albino Wistar rats of 6-7 postnatal weeks. The rats were divided into three case groups (E1: 4 h/d, 4 d/w; E2: 2 h/d, 4 d/w; E3: 2 h/d, 2 d/w) and one control group. The testes specimens were sectioned at 5 μm and stained with the haematoxylin and eosin staining technique for histological and morphometrical studies. We found a severe decrease in germ cells associated with spermatogenesis arrest in the E1 group. A decrease in germ cells and a thickening of the basal membrane of the seminiferous tubules were seen in E2. Displacement of Sertoli and germinal cells were also found in the E3 group. The mean seminiferous tubular diameter and seminiferous epithelial height in the experimental groups were decreased in comparison with the control group and the differences were statistically significant (p < 0. 05). The findings of this study revealed that chronic formaldehyde exposure can cause histopathological and morphometric changes to the seminiferous epithelium in rats and that these changes depend on the duration of the formaldehyde exposure. Copyright © 2007 Via Medica

Altered levels of nodal excitability by rate-dependent inhibitory effects of essential oil of Citrus aurantium on the electrophysiological properties of isolated perfused rabbit AV-Node. Protective role in the prevention of ouabain toxicity [Alteración de los niveles de excitabilidad nodal por efectos inhibitorios velocidad-dependiente del aceite esencial de Citrus aurantium sobre las propiedades electrofisiológicas del nodo AV aislado y perfundido de conejo. Papel protector en la prevención de toxicidad por ouabaína]

Treatment of supraventricular arrhythmia includes a wide range of medical interventions. Herbal remedies are suitable alternatives to synthetic drugs due to their availability, minimal side effects and lower price. Pharmacological studies and traditional medical literature point to the cardiovascular effects of Citrus aurantium L. (Rutaceae) in many instances. In the present study we used isolated perfused AV-node of rabbit as an experimental model to determine the effect of various concentrations of essential oil of C. aurantium (0.1-0.3 v/v) on the nodal conduction time and refractoriness of an isolated rabbit AV-nodal preparations. Selective stimulation protocols were used to independently quantify AV nodal recovery, facilitation and fatigue in 18 rabbits. Our results showed concentration-dependent and rate-independent suppressive effects of essence of C. aurantium on the Wenchebach cycle length (WBCL), AV Conduction Time (AVCT) and effective and functional refractory periods (ERP & FRP). Functional properties such as facilitation and fatigue were significantly increased by this plant. Citrus aurantium plays a protective role against the toxic effects of ouabaine by increasing AV nodal conduction time and refractoriness. The above results indicated differential effects of C. aurantium on slow and fast pathways, with a dominant role on fast pathways. This research has explained the protective role of C. aurantium on ouabaine toxicity. All results indicated the potential anti-arrhythmic effects of C. aurantium in treating supraventricular tachyarrhythmia

Morphometric alterations to the rat spleen following formaldehyde exposure

Formaldehyde is commonly used in the production of various industrial and medical products. At room temperature formaldehyde easily evaporates. Exposure to formaldehyde can be hazardous to human health. Studies show that the vapour can be the cause of clinical symptoms such as throat, eye, skin and nasal irritation. It can also decrease the production of IgM in the spleen cells. This study was designed to determine the morphometric changes to the spleen in rats when samples were exposed to formaldehyde for 18 weeks. A total of 28 albino Wistar rats aged 6-7 postnatal weeks were divided into the following three case groups according to their exposure to formaldehyde: E1 (2 h/day, 2 days/week), E2 (2 h/day, 4 days/week), E3 (4 h/day, 4 days/week) and one control group. When the exposure period had expired the animals were anaesthetised with chloroform. After cervical dislocation, the abdomen was dissected and spleen specimens were taken. These were sectioned and stained with the haematoxylin and eosin technique for morphometric study. Data was obtained from an Olympus light microscope and then analysed with SPSS (version 11.5) and one-way ANOVA test. The white pulp area and diameter and the marginal zone diameter were greater in group E3 than those in the other groups. The germinal centre area and diameter and the diameter of the periarterial lymphoid sheaths (PALS) were greater in group E2 than in other groups, although there was no significant difference between groups in the area of white pulp and the PALS diameter (p < 0.05). This study showed that formaldehyde vapour can cause morphometric changes in the white pulp of the spleen in rats. Copyright © 2008 Via Medica

Remodeling by fibroblasts alters the rate-dependent mechanical properties of collagen

The ways that fibroblasts remodel their environment are central to wound healing, development of musculoskeletal tissues, and progression of pathologies such as fibrosis. However, the changes that fibroblasts make to the material around them and the mechanical consequences of these changes have proven difficult to quantify, especially in realistic, viscoelastic three-dimensional culture environments, leaving a critical need for quantitative data. Here, we observed the mechanisms and quantified the mechanical effects of fibroblast remodeling in engineered tissue constructs (ETCs) comprised of reconstituted rat tail (type I) collagen and human fibroblast cells. To study the effects of remodeling on tissue mechanics, stress-relaxation tests were performed on ETCs cultured for 24, 48, and 72 h. ETCs were treated with deoxycholate and tested again to assess the ECM response. Viscoelastic relaxation spectra were obtained using the generalized Maxwell model. Cells exhibited viscoelastic damping at two finite time constants over which the ECM showed little damping, approximately 0.2 s and 10-30 s. Different finite time constants in the range of 1-7000 s were attributed to ECM relaxation. Cells remodeled the ECM to produce a relaxation time constant on the order of 7000 s, and to merge relaxation finite time constants in the 0.5-2 s range into a single time content in the 1 s range. Results shed light on hierarchical deformation mechanisms in tissues, and on pathologies related to collagen relaxation such as diastolic dysfunction. Statement of Significance As fibroblasts proliferate within and remodel a tissue, they change the tissue mechanically. Quantifying these changes is critical for understanding wound healing and the development of pathologies such as cardiac fibrosis. Here, we characterize for the first time the spectrum of viscoelastic (rate-dependent) changes arising from the remodeling of reconstituted collagen by fibroblasts. The method also provides estimates of the viscoelastic spectra of fibroblasts within a three-dimensional culture environment. Results are of particular interest because of the ways that fibroblasts alter the mechanical response of collagen at loading frequencies associated with cardiac contraction in humans. © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Autonomous Integrated Receive System (AIRS) requirements definition. Volume 2: Design and development

Functional requirements and specifications are defined for an autonomous integrated receive system (AIRS) to be used as an improvement in the current tracking and data relay satellite system (TDRSS), and as a receiving system in the future tracking and data acquisition system (TDAS). The AIRS provides improved acquisition, tracking, bit error rate (BER), RFI mitigation techniques, and data operations performance compared to the current TDRSS ground segment receive system. A computer model of the AIRS is used to provide simulation results predicting the performance of AIRS. Cost and technology assessments are included