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1.
Calciphylaxis – a topical overview 总被引:3,自引:0,他引:3
G Arseculeratne† AT Evans‡ SM Morley† 《Journal of the European Academy of Dermatology and Venereology》2006,20(5):493-502
'Calciphylaxis', a calcification syndrome associated with ischaemic cutaneous necrosis, is acquired naturally in humans in disease states. It is a life and limb-threatening complication, usually observed in patients with renal disease and secondary hyperparathyroidism, but known to occur in the absence of renal or parathyroid disease. The reported mortality rate, which ranges from 60-80%, relates to wound infection, sepsis and organ failure. It is a small-vessel vasculopathy, which is estimated to occur in about 4% of haemodialysis patients. Clinically, violaceous, reticulate areas of cutaneous necrosis and eschar may be evident, particularly in the extremities. In addition to the clinical picture, a raised calcium phosphorous product, an elevated parathyroid hormone level, radiographic evidence of vessel and soft-tissue calcification and the finding of mural calcification affecting small arteries and arterioles on histopathology help to confirm the diagnosis of this entity which generally has a poor prognosis. A high index of suspicion and an active multidisciplinary management approach, with rigorous attention to wound care and prevention of sepsis, are vital in the management of these patients. In this overview, we discuss the pathophysiology, clinical features and associations, risk factors, diagnosis and management issues relating to calciphylaxis. 相似文献
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Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy 总被引:3,自引:0,他引:3
Kelsell RE; Gregory-Evans K; Payne AM; Perrault I; Kaplan J; Yang RB; Garbers DL; Bird AC; Moore AT; Hunt DM 《Human molecular genetics》1998,7(7):1179-1184
The dominant cone-rod dystrophy gene CORD6 has previously been mapped to
within an 8 cM interval on chromosome 17p12-p13. The retinal- specific
guanylate cyclase gene (RETGC-1), which maps to within this genetic
interval and previously was implicated in Leber's congenital amaurosis, was
screened for mutations within this family and in a panel of small families
and individuals with various cone and cone- rod dystrophy phenotypes. A
missense mutation (E837D) was identified in affected members of the CORD6
family, as well as a second missense mutation (R838C) in three other
families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene
to be implicated in cone-rod dystrophy and this is the first report of
dominant mutations in this gene.
相似文献
5.
Multiple effects of dopamine on layer V pyramidal cell excitability in rat prefrontal cortex 总被引:5,自引:0,他引:5
The mechanisms underlying the inhibitory effects of dopamine (DA) on layer V pyramidal neuron excitability in the prelimbic region of the rat medial prefrontal cortex were investigated. Under control conditions, DA depressed both action potential generation (driven by somatic current injection) and input resistance (R(N)). The presence of GABA(A) receptor antagonists blocked DA-induced depression of action potential generation and revealed a delayed increase in excitability that persisted for the duration of experimental recording, up to 20 min following the washout of DA. In contrast to spike generation, disinhibition did not affect the transient depression of R(N) produced by DA, suggesting independent actions of DA on spike generation and R(N). Consistent with the hypothesis that DA acts to decrease pyramidal cell output via a GABAergic mechanism, DA increased the frequency of spontaneous inhibitory postsynaptic currents in both the absence and presence of TTX. Furthermore focal application of GABA to a perisomatic region mimicked the inhibitory effect of DA on spike production without affecting R(N). Focal application of bicuculline to the same location reversed the inhibitory effect of bath-applied DA on spike generation, while again having no effect on R(N). The depression of R(N) by DA was both occluded and mimicked by the Na(+) channel blocker TTX, suggesting the involvement of a Na(+) conductance in reducing pyramidal cell R(N) during the acute presence of DA. Together these data demonstrate that the acute presence of DA decreases pyramidal neuron excitability by two independent mechanisms. At the same time DA triggers a delayed and longer-lasting increase in excitability that is partially masked by synaptic inhibition. 相似文献
6.
Anderson RA; Wallace AM; Kicman AT; Wu FC 《Human reproduction (Oxford, England)》1997,12(8):1657-1662
Administration of supraphysiological doses of testosterone to normal men
causes inhibition of spermatogenesis, but while most become azoospermic,
30-55% maintain a low rate of spermatogenesis. We have investigated whether
there are differences in endogenous androgen production, of testicular and
adrenal origin, which may be related to the degree of suppression of
spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m.
injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic,
while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a
specific testicular product, was reduced to <10% of pretreatment values,
with no differences between the groups. Similar results were obtained for
other markers of testicular steroidogenesis. Urinary and plasma adrenal
androgens were also reduced during TE treatment: a statistically
significant decrease in both (P < 0.001 and P < 0.05 respectively)
was seen in the azoospermic but not oligozoospermic responders. These
results suggest that testicular steroidogenesis is decreased to <10% by
the administration of supraphysiological doses of exogenous testosterone.
Differences in the degree of ongoing steroidogenesis in the testis do not
appear to account for incomplete suppression of spermatogenesis, thus
differences in androgen metabolism may underlie this heterogeneous
response. A small but significant reduction in secretion of adrenal
androgens was also detectable, the relevance of which is unclear.
相似文献
7.
Berry V; Ionides AC; Moore AT; Plant C; Bhattacharya SS; Shiels A 《Human molecular genetics》1996,5(3):415-419
Inherited cataract is a clinically and genetically heterogeneous disease.
Here we report the identification of a new locus for an autosomal dominant
anterior polar cataract on the short arm of chromosome 17. To map this new
locus we performed genetic linkage analysis with microsatellite markers in
a four-generation pedigree. After exclusion of seven candidate loci for
cataract, we obtained significant positive LOD scores for markers D17S849
(Z = 4.01 / theta = 0.05) and D17S796 (Z = 4.17 / theta = 0.05). Multipoint
analysis gave a maximum LOD score of 5.2 (theta max = 0.06) between these
two markers. From haplotype analysis, the cataract locus lies in the 13 cM
interval between markers D17S849 and D17S796. This study provides the first
genetic mapping of an autosomal dominant anterior polar cataract.
相似文献
8.
Tamanini F; Willemsen R; van Unen L; Bontekoe C; Galjaard H; Oostra BA; Hoogeveen AT 《Human molecular genetics》1997,6(8):1315-1322
Lack of expression of the fragile X mental retardation protein (FMRP)
results in mental retardation and macroorchidism, seen as the major
pathological symptoms in fragile X patients. FMRP is a cytoplasmic RNA-
binding protein which cosediments with the 60S ribosomal subunit. Recently,
two proteins homologous to FMRP were discovered: FXR1 and FXR2. These novel
proteins interact with FMRP and with each other and they are also
associated with the 60S ribosomal subunit. Here, we studied the expression
pattern of the three proteins in brain and testis by immunohistochemistry.
In adult brain, FMR1, FXR1 and FXR2 proteins are coexpressed in the
cytoplasm of specific differentiated neurons only. However, we observed a
different expression pattern in fetal brain as well as in adult and fetal
testis, suggesting independent functions for the three proteins in those
tissues during embryonic development and adult life.
相似文献
9.
D E Parker D L Wood W L Gulledge R L Goodrich 《Aviation, space, and environmental medicine》1979,50(11):1112-1121
Two types of experiments concerning estimated magnitude of self-motion during exposure to linear oscillation on a parallel swing are described in this paper. Experiment I examined changes in magnitude estimation as a function of variation of the subject's head orientation, and Experiments II a, II b, and II c assessed changes in magnitude estimation performance following exposure to sustained, "intense" linear oscillation (fatigue-inducing stimulation). The subjects' performance was summarized employing Stevens' power law (R = k . Sn, where R is perceived self-motion magnitude, k is a constant, S is amplitude of linear oscillation, and n is an exponent). The results of Experiment I indicated that the exponents, n, for the magnitude estimation functions varied with head orientation and were greatest when the head was oriented 135 degrees off the vertical. In Experiments II a-c, the magnitude estimation function exponents were increased following fatigue. Both types of experiments suggest ways in which the vestibular system's contribution to a spatial orientation perceptual system may vary. This variability may be a contributing factor to the development of pilot/astronaut disorientation and may also be implicated in the occurrence of motion sickness. 相似文献
10.