The efficacy of excimer laser (308 nm) for vitiligo at different body sites

BACKGROUND: The treatment with XeCl-excimer laser generated 308-nm UVB radiation has shown promising results in patients with vitiligo. OBJECTIVE: In this controlled, prospective trial we studied the primary efficacy (start and grade of repigmentation) and patient's satisfaction of XeCl-excimer laser for treatment of vitiligo patches at different body sites and re-evaluated the achieved repigmentation 12 months after the end of therapy. METHODS: Twenty-five patients with generalized or localized vitiligo with a total of 85 lesions at different body sites were enrolled in this study. Vitiligo patches were treated with 308-nm XeCl-excimer laser 3 times a week for 6 to 10 weeks. The overall repigmentation grade of each treated lesion was evaluated once a week on a 5 point scale rating from 0 (no repigmentation), 1 (1-5%), 2 (6-25%), 3 (26-50%), 4 (51-75%), to 5 (76-100%). RESULTS: Twenty-four patients completed the study. Within 6 to 10 weeks of treatment 67% of the patients (16/24) developed follicular repigmentation of at least one of their vitiligo lesions. Lesion repigmentation started after a mean of 13 treatments in lesions located on the face, trunk, arm, and/or leg (high-responder location), and after a mean of 22 treatments in lesions located on the elbow, wrist, dorsum of the hand, knee, and/or dorsum of the foot (low-responder location). Untreated control lesions and lesions located on the fingers did not achieve any repigmentation. After 10 weeks of treatment repigmentation of more than 75% was found in 25% (7/28) of lesions of the high-responder location group versus 2% (1/43) of lesions of the low-responder location group. In most cases, laser-induced repigmentation was persistent, as determined 12 months after the end of treatment. CONCLUSIONS: 308-nm excimer laser is an effective modality for the treatment of vitiligo. However, similar to other non-surgical treatment modalities, the therapeutic effect is mainly dependent on the location of vitiligo lesions.     

Homozygous deletion mutations in the plectin gene (PLEC1) in patients with epidermolysis bullosa simplex associated with late-onset muscular dystrophy

In a distinct autosomal recessive variant of epidermolysis bullosa, EB- MD, life-long skin blistering is associated with late-onset muscular dystrophy of unknown etiology. Electron microscopy of these patients' skin suggests that tissue separation occurs intracellularly at the level of the hemidesmosomal inner plaque, which contains plectin, a high molecular weight cytoskeletal associated protein, also expressed in the sarcolemma of the muscle. In this study, we report two patients with EB-MD, each with a homozygous deletion mutation in the plectin gene, PLEC1. In the first case, the proband and her similarly affected sister had a homozygous 9 bp deletion mutation, designated as 2719de19, which resulted in elimination of three amino acids, QEA, in a sequence of 23 amino acids entirely conserved between the mouse and human sequences. The proband in the second family demonstrated a single nucleotide deletion at position 5866, designated as 5866delC, which resulted in frameshift and a premature termination codon for translation 16 bp downstream from the site of deletion. The absence of plectin in the hemidesmosomes, as reflected by negative immunofluorescence with an anti-plectin antibody (HD-1), associated with fragility of basal keratinocytes, implicates plectin as critical for binding of intermediate keratin filament network to hemidesmosomal complexes. The function of plectin as a putative attachment protein also in the muscle would explain the clinical phenotype consisting of cutaneous fragility and muscular dystrophy in EB-MD.      

False-negative results by polymerase chain reaction due to contamination by glove powder

The polymerase chain reaction (PCR) technique has become an important, widely employed method for the detection and quantitation of the nucleic acid sequences used in the diagnosis and monitoring of genetic and infectious diseases. Much attention has been directed at the problem of false-positive PCR results, which are generally attributed to low-level laboratory contamination of amplified sequences ("carryover"). In contrast, few investigators have commented on the somewhat less frequent, but equally problematic, false-negative PCR results. Investigation of the source of sporadic false-negative PCR reactions found that glove powder, inadvertently introduced into tubes when gloves are changed in an effort to reduce false-positive results, can nonspecifically inhibit each of the major steps in the PCR detection process. Methodologic precautions are recommended to minimize this problem.     

CLINICAL AUDIT: IS DAY-CASE ADENOTONSILLECTOMY SAFE?

SUMMARY The trend towards day-case procedures is growing, as a consequence not only of improved medical care but the increasing importance of economic considerations in today's healthcare environment. In the largest worldwide study to date to assess the safety of day-case adenotonsillectomy, we reviewed the records of 4386 patients at the otolaryngology department of the Bradford Royal Infirmary. We found a reactionary haemorrhage rate of 0.57%. All patients who underwent surgery in the morning session had presented with haemorrhage and returned to the operating theatre before the end of the afternoon session. We discuss the implications of these findings, and consider that with careful monitoring day-case tonsillectomy and/or adenoidectomy may safely be introduced.     

Platelet glycoprotein (Gp) IX associates with GpIb alpha in the platelet membrane GpIb complex

The platelet membrane glycoprotein (Gp) Ib complex consists of four polypeptides: the disulfide-linked GpIb alpha and GpIb beta subunits; GpIX, tightly, but noncovalently associated with GpIb alpha-beta; and the more weakly associated GpV. It is not certain whether the association of GpIX to Gplb alpha-beta is via GpIB alpha, GpIb beta, or both subunits, although recently published evidence implicates an interaction with GpIb beta. We have investigated the interaction of GpIX with GpIb alpha-beta using polyclonal rabbit antibodies to GpIb alpha and GpIb beta raised by immunization with purified glycocalicin and with synthetic peptide sequences from GpIb beta, respectively, as well as monoclonal antibodies directed against GpIX (FMC-25) and against GpIb alpha (AP-1). We performed two types of experiments, using either purified GpIb complex or platelets. (1) When wells were coated with nonreduced GpIb complex, the binding of FMC-25 was inhibited 73% by GpIb alpha antibody, but only 30% by the GpIb beta antibody; when wells were coated with reduced complex, FMC-25 binding was inhibited by the same two antibodies by 86% and 13%, respectively. When wells were coated with polyclonal GpIb alpha or GpIb beta antibodies and then incubated with reduced GpIb complex, only wells coated with GpIb alpha antibodies captured GpIX reactivity. When wells were coated with FMC-25 and then incubated with nonreduced GpIb complex, both the GpIb alpha and GpIb beta polyclonal antibodies reacted strongly; in contrast, only GpIb alpha reactivity was retained when wells coated with FMC-25 were incubated with reduced GpIb complex. In the reciprocal experiment, AP-1- coated wells incubated with either nonreduced or reduced GpIb complex bound radiolabeled FMC-25. (2) The ability of polyclonal GpIb alpha and GpIb beta antibodies to inhibit binding of FMC-25 to platelets was studied by ELISA and by flow cytometry. In both systems, FMC-25 binding was inhibited by the GpIb alpha antibody, but not significantly by the GpIb beta antibody. We conclude that GpIX is strongly associated with GpIb alpha in the purified platelet GpIb complex and in the platelet membrane.     

Influence of preload on left ventricular relaxation in isolated ejecting hearts during myocardial depression

BACKGROUND:

The controversially discussed intrinsic effect of end-diastolic pressure (EDP) on ventricular relaxation (lusitropy) is a prerequisite for interpretation of lusitropic changes induced by physiological and pharmacological interventions because the latter usually alter the ventricular loading conditions.

OBJECTIVES:

Characterization of the lusitropic effect of preload changes at low and high absolute EDP and after spontaneous cardiodepression.

METHODS:

Repeated preload tests (increasing cardiac inflow at constant mean aortic pressure) were performed in isolated ejecting rat and guinea pig hearts. Preload was quantified by left ventricular EDP, lusitropy was quantified using peak negative left ventricular pressure change velocity (−dP/dt), and relaxation time constant τ was calculated from monoexponential and four-parametric logistic pressure fall models. Regression coefficients of relaxation indexes, −dP/dt and τ versus EDP, were calculated and compared at different degrees of cardiac depression.

RESULTS:

Increasing EDP in the ejecting hearts less than 2 h after isolation caused τ to decrease and −dP/dt to increase initially at low EDP levels. Both parameters remained constant or even reversed at higher EDP levels. In the spontaneously depressed hearts, over 3 h after isolation, basic τ values were higher and −dP/dt values were lower, but EDP changes no longer had significant lusitropic effects. The same behaviour was observed in pentobarbital depressed hearts.

CONCLUSIONS:

A positive lusitropic effect (falling τ, rising −dP/dt) was observed when preload was increased in the range of lower EDP values in undepressed hearts early after isolation. However, preload changes did not influence lusitropy in isolated hearts either early after isolation at high EDP levels or in the spontaneously depressed condition at any EDP level.     

Protein C deficiency in a controlled series of unselected outpatients: an infrequent but clear risk factor for venous thrombosis (Leiden Thrombophilia Study) [see comments]

A deficiency of protein C (PC), antithrombin, or protein S is strongly associated with deep-vein thrombosis in selected patients and their families. However, the strength of the association with venous thrombosis in the general population is unknown. This study was a population-based, patient-control study of 474 consecutive outpatients, aged less than 70 years, with a first, objectively diagnosed, episode of venous thrombosis and without an underlying malignant disease, and 474 healthy controls who matched for age and sex. Relative risks were estimated as matched odds ratios. Based on a single measurement, there were 22 (4.6%) patients with a PC deficiency (PC activity, less than 0.67 U/mL or PC antigen, less than 0.33 U/mL when using coumarins). Among the controls, the frequency was 1.5% (seven subjects). Thus, there is a threefold increase in risk of thrombosis in subjects with PC levels below 0.67 or 0.33 U/mL [matched odds ratio, 3.1; 95% confidence interval (CI), 1.4 to 7.0]. When a PC deficiency was based on two repeated measurements, the relative risk for thrombosis increased to 3.8 (95% CI, 1.3 to 10); when it was based on DNA-confirmation, the relative risk increased further to 6.5 (95% CI, 1.8 to 24). In addition, there was a gradient in thrombosis risk, according to PC levels. The results for antithrombin are similar to those for PC, although less pronounced (relative risk, 2.2; 95% CI, 1.0 to 4.7). We could not find an association between reduced total protein S (relative risk, 0.7; 95% CI, 0.3 to 1.8) or free protein S levels (relative risk, 1.6; 95% CI, 0.6 to 4.0) and thrombosis risk. Although not very frequent, PC and antithrombin deficiency are clearly associated with an increase in thrombosis risk.     

结肠黑变病的研究现状及进展

随着便秘的发病率增加和结肠镜检查率提高,结肠黑变病的检出率明显升高,其具体的病因及发病机制不清,多与服用泻药和便秘有关.随着分子生物学技术的广泛应用及动物实验研究的深入,会逐步认识结肠黑变这种现象.目前研究的重点多集中于结肠黑变与结肠上皮细胞增殖与凋亡;泻剂滥用造成的结肠运动功能的改变的原理;该病与结肠肿瘤、息肉、息肉病等细胞增殖性疾病相关性.我们综述近年的相关文献,从流行病学、发病相关因素、病理形态学改变及治疗和预后等方面加以分析和总结,以期对该病以及相关疾病加深认识.