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Underlying Pathophysiological Mechanisms (underlying + pathophysiological_mechanism)
Selected AbstractsMigraine With Aura After Intracranial Endovascular ProceduresHEADACHE, Issue 4 2001R. Beekman MD Objective.,To describe three cases of migraine (two with aura) after an intracranial endovascular procedure. Method.,Retrospective. Results.,One patient had an attack of migraine with prolonged aura after embolization of a dural arteriovenous fistula. Another patient had an attack of migraine with aura (and hemiparesis) after a diagnostic angiogram. The third patient already suffered from migraine with aura and had a migraine attack after embolization of an occipital arteriovenous malformation. A quadrantanopia persisted in this patient. Outcome of the other two patients was good. Conclusion.,Intracranial endovascular procedures can induce migraine with aura. We could not identify the underlying pathophysiological mechanism, but mechanical, chemical, immunological, or hemodynamic factors could be involved. [source] Treatment-induced diabetic neuropathy: A reversible painful autonomic neuropathyANNALS OF NEUROLOGY, Issue 4 2010Christopher H. Gibbons MD Objective To describe the natural history, clinical, neurophysiological, and histological features, and outcomes of diabetic patients presenting with acute painful neuropathy associated with glycemic control, also referred to as insulin neuritis. Methods Sixteen subjects presenting with acute painful neuropathy had neurological and retinal examinations, laboratory studies, autonomic testing, and pain assessments over 18 months. Eight subjects had skin biopsies for evaluation of intraepidermal nerve fiber density. Results All subjects developed severe pain within 8 weeks of intensive glucose control. There was a high prevalence of autonomic cardiovascular, gastrointestinal, genitourinary, and sudomotor symptoms in all subjects. Orthostatic hypotension and parasympathetic dysfunction were seen in 69% of subjects. Retinopathy worsened in all subjects. Reduced intraepidermal nerve fiber density (IENFD) was seen in all tested subjects. After 18 months of glycemic control, there were substantial improvements in pain, autonomic symptoms, autonomic test results, and IENFD. Greater improvements were seen after 18 months in type 1 versus type 2 diabetic subjects in autonomic symptoms (cardiovascular p < 0.01; gastrointestinal p < 0.01; genitourinary p < 0.01) and autonomic function tests (p < 0.01, sympathetic and parasympathetic function tests). Interpretation Treatment-induced neuropathy is characterized by acute, severe pain, peripheral nerve degeneration, and autonomic dysfunction after intensive glycemic control. The neuropathy occurred in parallel with worsening diabetic retinopathy, suggesting a common underlying pathophysiological mechanism. Clinical features and objective measures of small myelinated and unmyelinated nerve fibers can improve in these diabetic patients despite a prolonged history of poor glucose control, with greater improvement seen in patients with type 1 diabetes. ANN NEUROL 2010;67:534,541 [source] On the role of cortical glutamate inobsessive-compulsive disorder and attention-deficit hyperactivity disorder, two phenomenologically antithetical conditionsACTA PSYCHIATRICA SCANDINAVICA, Issue 6 2000Maria L. CarlssonArticle first published online: 24 DEC 200 Objective: The objective of the present study was to compare the phenomenology and pathophysiology of obsessive-compulsive disorder (OCD) and attention-deficit hyperactivity disorder/deficits in attention, motor control and perception (ADHD/DAMP). Method: Through detailed studies of the literature on OCD and ADHD/DAMP the phenomenology of these two conditions is compared, and possible underlying pathophysiological mechanisms involving interactions between glutamate, dopamine, serotonin and acetylcholine are discussed, with emphasis on OCD. The present paper also discusses possible mechanisms of action for current pharmacological treatments of OCD and ADHD, as well as possible future treatment strategies for these disorders. Results: OCD and ADHD/DAMP are common neuropsychiatric conditions which in many regards appear to be each other's antipodes with respect to clinical manifestations, associated personality traits and brain biochemistry, notably prefrontal cortical glutamate activity. Future pharmacological treatments of these disorders may involve manipulations with glutamate, dopamine D1, serotonin 2A and nicotine receptors. Conclusion: It appears that OCD is a hyperglutamatergic and ADHD a hypoglutamatergic condition, with prefrontal brain regions being especially affected. [source] Analysis of circadian variation of acute myocardial infarction: afternoon predominance in Turkish populationINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 1 2009I. Sari Summary Background:, Although data about circadian variation of myocardial infarction (MI) in western populations reveal morning peak between 06:00 and 12:00 hours, differences have been reported in different regions of the world and ethnic groups. We aimed to evaluate circadian variation of MI in a Turkish cohort. Methods:, A total of 476 patients (mean age 56.7 ± 11.7; 80% men) with acute st elevation MI were included into the study. Patients were categorised into four 6-h increments (00:01,06:00; 06:01,12:00; 12:01,18:00 and 18:01,24:00 hours). Results:, Onset of MI exhibited significant circadian variation among four time periods (p < 0.001), demonstrating afternoon peak (between 12:01 and 18:00 hours) and trough between 00:01 and 06:00 hours. Incidence of MI between 12:01 and 18:00 hours was significantly higher when compared with other three 6-h periods (p = 0.001). Incidence of MI between 00:01 and 06:00 hours was significantly lower when compared with other three 6-h periods (p = 0.001). Incidence of MI between 12:01 and 18:00 hours was 1.64 times that of average frequency of the remaining 18:00 hours of the day and 2.3 times that of frequency between 00:01 and 06:00 hours. When analysed for the subgroups of the study sample, only smoking blunted the afternoon peak. Conclusions:, Instead of early morning peak in western countries, there is afternoon predominance in circadian variation of MI in a Turkish cohort. It may be related with genetic and/or demographic characteristics of Turkish population. Further studies are required to determine underlying pathophysiological mechanisms causing these differences in chronobiology of MI among populations. [source] Emerging treatments for pulmonary arterial hypertensionTHE CLINICAL RESPIRATORY JOURNAL, Issue 3 2008Dermot S. O'Callaghan Abstract Introduction:, Pulmonary arterial hypertension (PAH) is a rare, progressive disease for which no cure exists. However, improved understanding of underlying pathophysiological mechanisms has led to the development of several effective treatments that improve haemodynamics and functional status. Objective:, An overview of emerging pharmacological approaches to the management of PAH is presented. Materials and methods:, A Medline search was performed for studies describing novel treatments and potential therapeutic targets relevant to PAH. Results:, Several different treatments that modulate abnormalities in the prostacyclin, endothelin and nitric oxide pathways have shown efficacy in randomised, controlled studies and are now licensed for use for PAH patients with advanced disease. Furthermore, there is now encouraging long-term survival data associated with use of these agents. A number of other targets with therapeutic potential have also been identified, such as serotonin, platelet-derived growth factor and vasoactive intestinal peptide. Recently, strategies involving combinations of different PAH-specific agents have emerged as a promising approach for those failing monotherapy. Conclusion:, The therapeutic options available for PAH has improved considerably in recent years and is likely to expand in the future. Please cite this paper as: O'Callaghan DS. Emerging treatments for pulmonary arterial hypertension. The Clinical Respiratory Journal 2008; 2: 132,140. [source] UNRAVELLING THE PATHOPHYSIOLOGY OF COMPLEX REGIONAL PAIN SYNDROME: FOCUS ON SYMPATHETICALLY MAINTAINED PAINCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 7 2008Gael F Gibbs SUMMARY 1In diseases such as complex regional pain syndrome (CRPS), where neuropathic pain is the primary concern, traditional pain classifications and lesion descriptors are of limited value. To obtain better treatment outcomes for patients, the underlying pathophysiological mechanisms of neuropathic pain need to be elucidated and analysed so that therapeutic targets can be identified and specific treatments developed. 2In the present review, we examine the current literature on sympathetically maintained pain (SMP), a subset of neuropathic pain, within the context of CRPS. Evidence from both human and animal studies is presented and discussed in terms of its support for the existence of SMP and the mechanistic information it provides. 3We discuss three current hypotheses that propose both a site and method for sympathetic,sensory coupling: (i) direct coupling between sympathetic and sensory neurons in the dorsal root ganglion; (ii) chemical coupling between sympathetic and nociceptive neuron terminals in skin; and (iii) the development of a-adrenoceptor-mediated supersensitivity in nociceptive fibres in skin in association with the release of inflammatory mediators. 4Finally, we propose a new hypothesis that integrates the mechanisms of chemical coupling and a-adrenoceptor-mediated supersensitivity. This hypothesis is based on previously unpublished data from our laboratory showing that a histological substrate suitable for sympathetic,sensory coupling exists in normal subjects. In the diseased state, the nociceptive fibres implicated in this substrate may be activated by both endogenous and exogenous noradrenaline. The mediating a-adrenoceptors may be expressed on the nociceptive fibres or on closely associated support cells. [source] | ||||||||||