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Secondary Changes (secondary + change)
Selected AbstractsCellular Damage and Prevention in Childhood HydrocephalusBRAIN PATHOLOGY, Issue 3 2004Marc R. Del Bigio The literature concerning brain damage due to hydrocephalus, especially in children and animal models, is reviewed. The following conclusions are reached: 1Hydrocephalus has a deleterious effect on brain that is dependent on magnitude and duration of ventriculomegaly and modified by the age of onset. 2Animal models have many histopathological similarities to humans and can be used to understand the pathogenesis of brain damage. 3Periventricular axons and myelin are the primary targets of injury. The pathogenesis has similarities to traumatic and ischemic white matter injury. Secondary changes in neurons reflect compensation to the stress or ultimately the disconnection. 4Altered efflux of extracellular fluid could result in accumulation of waste products that might interfere with neuron function. Further research is needed in this as well as the blood-brain barrier in hydrocephalus. 5Some, but not all, of the changes are preventable by shunting CSF. However, axon loss cannot be reversed, therefore shunting in a given case must be considered carefully. 6Experimental work has so far failed to show any benefit in reducing CSF production. Pharmacologic protection of the brain, at least as a temporary measure, holds some promise but more pre-clinical research is required. [source] Increased temperature sensitivity of net DOC production from ombrotrophic peat due to water table draw-downGLOBAL CHANGE BIOLOGY, Issue 4 2009J. M. CLARK Abstract The production and release of dissolved organic carbon (DOC) from peat soils is thought to be sensitive to changes in climate, specifically changes in temperature and rainfall. However, little is known about the actual rates of net DOC production in response to temperature and water table draw-down, particularly in comparison to carbon dioxide (CO2) fluxes. To explore these relationships, we carried out a laboratory experiment on intact peat soil cores under controlled temperature and water table conditions to determine the impact and interaction of each of these climatic factors on net DOC production. We found a significant interaction (P < 0.001) between temperature, water table draw-down and net DOC production across the whole soil core (0 to ,55 cm depth). This corresponded to an increase in the Q10 (i.e. rise in the rate of net DOC production over a 10 °C range) from 1.84 under high water tables and anaerobic conditions to 3.53 under water table draw-down and aerobic conditions between ,10 and , 40 cm depth. However, increases in net DOC production were only seen after water tables recovered to the surface as secondary changes in soil water chemistry driven by sulphur redox reactions decreased DOC solubility, and therefore DOC concentrations, during periods of water table draw-down. Furthermore, net microbial consumption of DOC was also apparent at , 1 cm depth and was an additional cause of declining DOC concentrations during dry periods. Therefore, although increased temperature and decreased rainfall could have a significant effect on net DOC release from peatlands, these climatic effects could be masked by other factors controlling the biological consumption of DOC in addition to soil water chemistry and DOC solubility. These findings highlight both the sensitivity of DOC release from ombrotrophic peat to episodic changes in water table draw-down, and the need to disentangle complex and interacting controls on DOC dynamics to fully understand the impact of environmental change on this system. [source] Association of tightly locked occlusion with temporomandibular disordersJOURNAL OF ORAL REHABILITATION, Issue 3 2007M.-Q. WANG summary, The association between teeth loss and temporomandibular disorders (TMD) is still inconclusive. A kind of secondary changes of the occlusion after teeth lose called the tightly locked occlusion (TLO), defined as the occluding contact that delivers angled occlusal force on the drifted neighbour and/or the tipped antagonists of the lost posterior teeth, was hypothesized to be association with TMD. The study aimed at investigating the association between the TLO and TMD. A total of 113 posterior-teeth losing patients, 64 with TMD symptoms (group of TMD) and 49 without (group of TMD-Free) were included. Study casts and joint radiographs were made to diagnose the TLO and joint morphological changes. The simultaneous contribution of the potential variables of gender, age, tooth losing number, the TLO, joint symmetry and signs of osteoarthrosis shown on radiographs were tested through binary logistic regression analysis. In women, the TLO entered into logistic model, and had an effect on the incidence of TMD (P = 0·008). The odds ratio of with-TLO versus without-TLO is 2·6 (95% CI: 1·2, 5·8) after controlling for the effect of gender. Age, tooth lose number, joint asymmetry or osseous changes had no effect on the incidence of TMD. The tightly locked occlusion is associated with some signs and symptoms of TMD. Randomized controlled trials will be needed in further studies to test the hypothesis that treatment of a TLO, as defined in the present study, will have a beneficial effect on the signs and symptoms of TMD. [source] Proteomic profiling of antisense-induced exon skipping reveals reversal of pathobiochemical abnormalities in dystrophic mdx diaphragmPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 3 2009Philip Doran Abstract The disintegration of the dystrophin,glycoprotein complex represents the initial pathobiochemical insult in Duchenne muscular dystrophy. However, secondary changes in signalling, energy metabolism and ion homeostasis are probably the main factors that eventually cause progressive muscle wasting. Thus, for the proper evaluation of novel therapeutic approaches, it is essential to analyse the reversal of both primary and secondary abnormalities in treated muscles. Antisense oligomer-mediated exon skipping promises functional restoration of the primary deficiency in dystrophin. In this study, an established phosphorodiamidate morpholino oligomer coupled to a cell-penetrating peptide was employed for the specific removal of exon 23 in the mutated mouse dystrophin gene transcript. Using DIGE analysis, we could show the reversal of secondary pathobiochemical abnormalities in the dystrophic diaphragm following exon-23 skipping. In analogy to the restoration of dystrophin, ,-dystroglycan and neuronal nitric oxide synthase, the muscular dystrophy-associated differential expression of calsequestrin, adenylate kinase, aldolase, mitochondrial creatine kinase and cvHsp was reversed in treated muscle fibres. Hence, the re-establishment of Dp427 coded by the transcript missing exon 23 has counter-acted dystrophic alterations in Ca2+ -handling, nucleotide metabolism, bioenergetic pathways and cellular stress response. This clearly establishes the exon-skipping approach as a realistic treatment strategy for diminishing diverse downstream alterations in dystrophinopathy. [source] Morphological changes induced in the pig kidney by extracorporeal shock wave lithotripsy: Nephron injuryTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2003Youzhi Shao Abstract While shock wave lithotripsy (SWL) is known to cause significant damage to the kidney, little is known about the initial injury to cells along the nephron. In this study, one kidney in each of six juvenile pigs (6,7 weeks old) was treated with 1,000 shock waves (at 24 kV) directed at a lower pole calyx with an unmodified HM-3 lithotripter. Three pigs were utilized as sham-controls. Kidneys were fixed by vascular perfusion immediately after SWL or sham-SWL. Three of the treated kidneys were used to quantitate lesion size. Cortical and medullary samples for light (LM) and transmission electron microscopy (TEM) were taken from the focal zone for the shock waves (F2), the contralateral kidney, and the kidneys of sham-SWL pigs. Because preservation of the tissue occurred within minutes of SWL, the initial injury caused by the shock waves could be separated from secondary changes. No tissue damage was observed in contralateral sham-SWL kidneys, but treated kidneys showed signs of injury, with a lesion of 0.2% ± 0.1% of renal volume. Intraparenchymal hemorrhage and injury to tubules was found at F2 in both the cortex and medulla of SWL-treated kidneys. Tubular injury was always associated with intraparenchymal bleeding, and the range of tissue injury included total destruction of tubules, focal cellular fragmentation, necrosis, cell vacuolization, and membrane blebbing. The initial injury caused by SWL was cellular fragmentation and necrosis. Cellular vacuolization, membrane blebbing, and disorganization of apical brush borders appear to be secondary changes related to hypoxia. Anat Rec Part A 275A:979,989, 2003. © 2003 Wiley-Liss, Inc. [source] Is there an increased frequency of food allergy in children delivered by caesarean section compared to those delivered vaginally?ACTA PAEDIATRICA, Issue 2 2009Bente Kvenshagen Abstract Aim: Allergic diseases are increasing. At the same time an increasing number of children are delivered by caesarean section. These children do not get the same contact with their mother's gut flora as babies delivered vaginally. Theoretically, lack of exposure to maternal vaginal and perineal bacteria might change the gut flora, with secondary changes in the immune system. The aim of this study was to investigate whether children delivered by caesarean section were more prone to develop food allergy. Methods: Six hundred and nine children were included at birth. At 2-year follow-up, 512 children participated, 171 delivered by caesarean section, 341 born vaginally. The children reported to have symptoms consistent with possible food allergy, were examined at the outpatient clinic. The diagnosis was based on the history, skin prick test (SPT), specific IgE, elimination/challenge test and double blind placebo controlled challenge. Results: Thirty-five (6.8%) children were diagnosed with adverse reactions to food, 27 with non-IgE-mediated and eight with IgE-mediated allergy. There was no over representation of children born by caesarean section. Conclusion: In this study there seems to be no increased risk for food allergy in the first 2 years of life in children delivered by caesarean section. [source] Renal And Cardiac Sympathetic Baroreflexes In Hypertensive RabbitsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2001Geoffrey A Head SUMMARY 1. The purpose of the present study was to assess the changes to renal sympathetic nerve activity (RSNA) baroreflexes during the development of hypertension after renal clipping in conscious rabbits. 2. Rabbits were fitted with a clip on the right renal artery or underwent a sham operation under halothane anaesthesia. A recording electrode was implanted on the left renal nerve 1 week before the experiment, 3 or 6 weeks after the initial operation. During the experiment, drug-induced ramp rises and falls in mean arterial pressure (MAP) were used to produce RSNA and heart rate (HR) baroreflex curves. The RSNA for each experiment was calibrated against maximum RSNA evoked by stimulation of baroreceptor-independent trigeminal afferents. 3. Mean arterial pressure was 20 and 36% higher 3 and 6 weeks after clip implantation, respectively. Renal sympathetic nerve activity baroreflex curves were reset rightwards accordingly, but the shape of the RSNA curves was differentially affected. 4. At both hypertensive periods, MAP,HR baroreflex gain was markedly reduced due to a reduction in curvature. The HR baroreflex range was increased. The RSNA baroreflex gain was reduced at 3 weeks, which was due to a 35% lower RSNA baroreflex range, but was similar to sham animals at 6 weeks. 5. The results show that, in established two kidney, one clip hypertension in rabbits, the sympathetic baroreflex is relatively well preserved but sensitivity of cardiac baroreflexes is attenuated. Therefore, the short-term inhibition of RSNA baroreflexes is not related to the level of blood pressure or the development of secondary changes, such as cardiac or vascular hypertrophy, but may be related to circulating angiotensin, which is known to increase at this time. [source] | |||||||||||||