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New Subtype (new + subtype)
Selected AbstractsChlorotoxin-sensitive Ca2+ -activated Cl, channel in type R2 reactive astrocytes from adult rat brainGLIA, Issue 4 2003Stanislava Dalton Abstract Astrocytes express four types of Cl, or anion channels, but Ca2+ -activated Cl, (ClCa) channels have not been described. We studied Cl, channels in a morphologically distinct subpopulation (, 5% of cells) of small (10,12 ,m, 11.8 ± 0.6 pF), phase-dark, GFAP-positive native reactive astrocytes (NRAs) freshly isolated from injured adult rat brains. Their resting potential, ,57.1 ± 4.0 mV, polarized to ,72.7 ± 4.5 mV with BAPTA-AM, an intracellular Ca2+ chelator, and depolarized to ,30.7 ± 6.1 mV with thapsigargin, which mobilizes Ca2+ from intracellular stores. With nystatin-perforated patch clamp, thapsigargin activated a current that reversed near the Cl, reversal potential, which was blocked by Cl, channel blockers, 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) and Zn2+, by I, (10 mM), and by chlorotoxin (EC50 = 47 nM). With conventional whole-cell clamp, NPPB- and Zn2+ -sensitive currents became larger with increasing [Ca2+]i (10, 150, 300 nM). Single-channel recordings of inside-out patches confirmed Ca2+ sensitivity of the channel and showed open-state conductances of 40, 80, 130, and 180 pS, and outside-out patches confirmed sensitivity to chlorotoxin. In primary culture, small phase-dark NRAs developed into small GFAP-positive bipolar cells with chlorotoxin-sensitive ClCa channels. Imaging with biotinylated chlorotoxin confirmed the presence of label in GFAP-positive cells from regions of brain injury, but not from uninjured brain. Chlorotoxin-tagged cells isolated by flow cytometry and cultured up to two passages exhibit positive labeling for GFAP and vimentin, but not for prolyl 4-hydroxylase (fibroblast), A2B5 (O2A progenitor), or OX-42 (microglia). Expression of a novel chlorotoxin-sensitive ClCa channel in a morphologically distinct subpopulation of NRAs distinguishes these cells as a new subtype of reactive astrocyte. GLIA 42:325,339, 2003. © 2003 Wiley-Liss, Inc. [source] Sporadic dystrophic epidermolysis bullosa with albopapuloid and prurigo- and folliculitis-like lesionsINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 8 2009Yi-Ming Fan MD A case of sporadic dystrophic epidermolysis bullosa (DEB) with albopapuloid and prurigo- and folliculitis-like lesions is reported. Histopathology of the scalp biopsy showed hyperkeratosis, a subepidermal cleft near the orifice of a hair follicle, dermal fibrosis, and a moderate perivascular and perifollicular lymphohistiocytic inflammatory cell infiltrate in the papillary dermis, without neutrophilic infiltrate in the orifice of the hair follicle. It is uncertain whether the present case should be classified as DEB pruriginosa or represents a new subtype of DEB. [source] Pretibial epidermolysis bullosa: is this case a new subtype with loss of types IV and VII collagen?INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 8 2009Hong-sun Lee MD Pretibial epidermolysis bullosa (PEB) is an extremely rare subtype of dominant dystrophic epidermolysis bullosa (DDEB), in which recurrent blistering with scarring predominantly involves the pretibial skin. Nail dystrophy, albopapuloid lesions, and hypertrophic scars may also occur. In PEB, immunohistochemical and electron microscopic studies demonstrate the complete or partial loss of the anchoring fibril (AF) in the basement membrane zone, suggesting disturbed synthesis or excessive degradation of collagen VII, the main component of AF. Interestingly, we report a case of PEB with unusual results of joint loss of types IV and VII collagen. [source] The M5 muscarinic receptor as possible target for treatment of drug abuseJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 6 2009R. B. Raffa Summary Two reports published in the latter 1980s are generally given credit for being the first to announce the discovery of a new subtype of muscarinic acetylcholine receptor (mAChR), designated m5 or M5, and now officially M5 (1). Both identifications were assigned using molecular biology techniques. Then , as now , no selective high-affinity ligands or toxins were available. In situ hybridization and reverse-transcriptase PCR have found M5 AChR expression in brain to be distinct from that of the four other G protein-coupled mAChR subtypes and primarily localized to the substantia nigra, ventral tegmental area, hippocampus (CA1 and CA2 subfields), cerebral cortex (outermost layer) and striatum (caudate putamen). M5 AChR brain region localization and involvement in the regulation of striatal dopamine release and in rewarding brain stimulation suggests a possible role for M5 AChR as a target for novel therapy to treat excess hedonic drive, including drug abuse. [source] Classification conundrums in paroxysmal dyskinesias: A new subtype or variations on classic themes?MOVEMENT DISORDERS, Issue 8 2005Michael H. Pourfar MD Abstract Paroxysmal movement disorders are a group of heterogeneous entities that have been categorized based on their most salient features. The four classic categories of paroxysmal dyskinesias are kinesigenic, nonkinesigenic, hypnogenic, and exercise-induced. The phenotypic variability of these disorders, coupled with new insights into their possible etiologies, has made the task of classification increasingly problematic. We describe 4 cases that do not fit easily into the current classification scheme, compare them with four others recently described in the literature, and raise the question as to whether they constitute a new subtype. © 2005 Movement Disorder Society [source] Subtypes of substance dependence and abuse: implications for diagnostic classification and empirical researchADDICTION, Issue 2006Thomas F. Babor ABSTRACT Aims To evaluate the relevance of a form of diagnostic classification called clinical subtyping in relation to possible revisions in the diagnostic criteria for substance abuse and dependence in psychiatric classification systems. Methods A general rationale for subtyping is presented. To explore the implications for diagnostic classification, recent research on a variety of subtyping schemes is reviewed in terms of the development of new subtypes and the validation of established theories. Results Subtypes of alcoholism and other psychiatric disorders have been proposed since the beginning of modern psychiatry. Recent subtyping research suggests that no consensus has emerged about the nature, much less the number, of subtypes that could be used to characterize the clinical heterogeneity assumed to be present in groups of people with substance use disorders. Although several relatively simple binary typologies have been developed (e.g. Cloninger's type I and type II; Babor et al.'s type A and type B), validation research has produced mixed results in terms of the construct, concurrent and predictive validity of these classifications. Conclusions The adoption of a subtyping scheme in the major psychiatric classification systems is not recommended until further international research is conducted. [source] | ||||||||||