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Predisposed Individuals (predisposed + individual)
Selected AbstractsN -methyl- d -aspartate, hyperpolarization-activated cation current (Ih) and ,-aminobutyric acid conductances govern the risk of epileptogenesis following febrile seizures in rat hippocampusEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2010Mohamed Ouardouz Abstract Febrile seizures are the most common types of seizure in children, and are generally considered to be benign. However, febrile seizures in children with dysgenesis have been associated with the development of temporal lobe epilepsy. We have previously shown in a rat model of dysgenesis (cortical freeze lesion) and hyperthermia-induced seizures that 86% of these animals developed recurrent seizures in adulthood. The cellular changes underlying the increased risk of epileptogenesis in this model are not known. Using whole cell patch-clamp recordings from CA1 hippocampal pyramidal cells, we found a more pronounced increase in excitability in rats with both hyperthermic seizures and dysgenesis than in rats with hyperthermic seizures alone or dysgenesis alone. The change was found to be secondary to an increase in N -methyl- d -aspartate (NMDA) receptor-mediated excitatory postsynaptic currents (EPSCs). Inversely, hyperpolarization-activated cation current was more pronounced in naïve rats with hyperthermic seizures than in rats with dysgenesis and hyperthermic seizures or with dysgenesis alone. The increase in GABAA -mediated inhibition observed was comparable in rats with or without dysgenesis after hyperthermic seizures, whereas no changes were observed in rats with dysgenesis alone. Our work indicates that in this two-hit model, changes in NMDA receptor-mediated EPSCs may facilitate epileptogenesis following febrile seizures. Changes in the hyperpolarization-activated cation currents may represent a protective reaction and act by damping the NMDA receptor-mediated hyperexcitability, rather than converting inhibition into excitation. These findings provide a new hypothesis of cellular changes following hyperthermic seizures in predisposed individuals, and may help in the design of therapeutic strategies to prevent epileptogenesis following prolonged febrile seizures. [source] Rats bred for high alcohol drinking are more sensitive to delayed and probabilistic outcomesGENES, BRAIN AND BEHAVIOR, Issue 7 2008C. J. Wilhelm Alcoholics and heavy drinkers score higher on measures of impulsivity than nonalcoholics and light drinkers. This may be because of factors that predate drug exposure (e.g. genetics). This study examined the role of genetics by comparing impulsivity measures in ethanol-naive rats selectively bred based on their high [high alcohol drinking (HAD)] or low [low alcohol drinking (LAD)] consumption of ethanol. Replicates 1 and 2 of the HAD and LAD rats, developed by the University of Indiana Alcohol Research Center, completed two different discounting tasks. Delay discounting examines sensitivity to rewards that are delayed in time and is commonly used to assess ,choice' impulsivity. Probability discounting examines sensitivity to the uncertain delivery of rewards and has been used to assess risk taking and risk assessment. High alcohol drinking rats discounted delayed and probabilistic rewards more steeply than LAD rats. Discount rates associated with probabilistic and delayed rewards were weakly correlated, while bias was strongly correlated with discount rate in both delay and probability discounting. The results suggest that selective breeding for high alcohol consumption selects for animals that are more sensitive to delayed and probabilistic outcomes. Sensitivity to delayed or probabilistic outcomes may be predictive of future drinking in genetically predisposed individuals. [source] Implicit Associations in Tension-Type Headaches: A Cognitive Analysis Based on Stress Reactivity ProcessesHEADACHE, Issue 8 2006Jennifer F. Armstrong BS Objective.,To determine whether tension-type headache (TTH) patients display stronger associations between negative events and headache-related information than headache-free controls. Background.,Generally, stress/diathesis models are common in clinical research and in the context of TTHs specifically. Data involving stress reactivity processes are compatible with such models. However, it would be of interest to tap the associative cognitive processes that likely mediate such relations. Methods.,In the present study, we selectively recruited individuals who do (n = 19) and do not (n = 19) suffer from episodic TTHs. We examined implicit associations between negative evaluations and headache-related information through the use of an implicit association test. Results.,As hypothesized, TTH patients displayed associations between negative evaluations and headache-related information, whereas the control group did not. Conclusions.,These data provide initial support for a plausible cognitive model for the occurrence of TTHs among predisposed individuals. [source] Loudness dependence of evoked dipole source activity during acute serotonin challenge in femalesHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 1 2008Christine Norra Abstract Objectives Direct challenge of cortical serotonergic (5-hydroxytryptamine, 5-HT) availability by tryptophan depletion test (TDT) was used to assess the hypothesized inverse relationship between central 5-HT function and loudness dependence of auditory evoked potentials (LDAEPs). Gender must be taken into particular account here, since there are gender differences in 5-HT brain synthesis, with women reacting more strongly to TDT. Methods In a double-blind, controlled cross-over study, 16 healthy females were ingested two highly concentrated amino acid mixtures with (+TRP) or without TRP (,TRP). While monitoring TRP levels and mood states, the AEP of different loudness stimuli were recorded, followed by dipole source analysis. Results Under the ,TRP condition, free plasma TRP levels decreased by 81.10% (±5.14). Most of the loudness change rates of the relevant N1/P2 tangential dipole activities were significantly increased under ,TRP, but calculated LDAEP did not differ significantly between treatments. LDAEP and states of mood were not correlated. Conclusions Despite strong TRP depletion, the results did not reach sufficient evidence that LDAEP is a valid biological marker of central 5-HT activity in females when using TDT. This agrees with the literature and supports the view that LDAEP indicates predominantly biological vulnerability in predisposed individuals. Copyright © 2007 John Wiley & Sons, Ltd. [source] IL-5-induced airway eosinophilia , the key to asthma?IMMUNOLOGICAL REVIEWS, Issue 1 2001Eckard Hamelmann Summary: Bronchial asthma is a chronic inflammatory airway disease defined by reversible airway obstruction and non-specific airway hyper-responsiveness (AHR). Although profound insights have been made into the pathophysiology of asthma, the exact mechanisms inducing and regulating the disease are still not fully understood. Yet, it is generally accepted that the pathological changes in asthma are induced by a chronic inflammatory process which is characterized by infiltration of the bronchial mucosa with lymphocytes and eosinophils, increased mucus production and submucosal edema. There is increasing evidence that an imbalance in the T-helper (Th) cell response of genetically predisposed individuals to common environmental antigens plays a pivotal role in the pathogenesis of allergic bronchial asthma and other atopic disorders. Following allergic sensitization, T cells from atopic patients tend to produce elevated levels of Th2-type cytokines, especially interleukin (IL)-4, IL-13, IL-5 and IL-6, which induce and regulate IgE production and eosinophil airway infiltration. In this review, the role of Th2-type cytokines, IgE and airway eosinophils in the induction of airway inflammation and AHR is discussed, and animal studies of asthma and AHR, mainly in rodents will be considered. A better understanding of the underlying mechanisms leading to asthma pathology may yield more specific immunological strategies for the treatment of this disease which is increasing worldwide. I thank the many colleagues in the laboratory of Dr. E. W. Gelfand, National Jewish Research Center, Denver CO, USA, for continuous support and encouragement. E.H. is a fellow of the Deutsche Forschungsgemeinschaft (DFG Ha 2162/1-1 and 2-1). [source] Pancreatic stem cells: a therapeutic agent that may offer the best approach for curing type 1 diabetesPEDIATRIC DIABETES, Issue 4 2001M Chaudhari Chaudhari M, Cornelius JG, Schatz D, Peck AB, Ramiya VK. Pancreatic stem cells: a therapeutic agent that may offer the best approach for curing type 1 diabetes. Abstract: Type 1 (insulin-dependent) diabetes is one of the most costly chronic diseases of children and adolescents in North America and Europe. It occurs in genetically predisposed individuals when the immune system attacks and destroys specifically the insulin-producing beta cells of the pancreatic islets of Langerhans. Although routine insulin injections can provide diabetic patients their daily insulin requirements, non-compliance commonly results in blood glucose excursions that eventually lead to microvascular and macrovascular complications and early death. The only real ,cure' for type 1 diabetes is replacement of the beta-cell mass which, today, is either an ectopancreatic transplant or an islet of Langerhans implant. Two new developments may offer additional options: surrogate, non-endocrine cells genetically modified to secrete insulin in response to high blood glucose levels; and stem cells that possess the capacity to differentiate to endocrine pancreas. In this short review, we discuss the efforts currently being made to regulate pancreatic stem cell growth in order to produce large numbers of functional islets that can be used as implants. Hopefully, autologous stem cell-derived islet cell implants without lifelong immunosuppressive therapy may one day be realized. [source] Behçet's disease and vitiligo in two brothers: coincidence or association?CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 8 2009M. Borlu Summary Behçet's disease (BD) and vitiligo are disorders with unknown aetiology. We report on two brothers with ocular Behcet's disease who had advanced unilateral ophthalmic symptoms associated with vitiligo. The two brothers had recurrent oral and genital ulceration, uveitis and white patches on their skin. The most probable hypothesis for the aetiology of BD is that of an autoimmune reaction in genetically predisposed individuals, with vasculitis as the main pathological hallmark. Despite many years of research, the specific causes of vitiligo remain obscure, and the most advanced aetiological hypothesis remains that of autoimmunity. To our knowledge, this is the first reported case within the literature of BD associated with vitiligo. The existence of the two different disorders is noteworthy as they were observed in two brothers during the same period in their lives, with very similar clinical observations. [source] | |||||||||||||