Klinische Wertigkeit einer dermatoskopischen Klassifikation von Clark‐Nävi

Background and objectives: The aim of this study was to evaluate the practical value of the dermatoscopic classification of Clark nevi Patients and methods: Dermatoscopic images of 268 lesions clinically and dermatoscopically diagnosed as Clark nevi were presented to 2 dermatologists without knowledge of the histological diagnosis. The dermatologists evaluated the lesions according to a simplified version of the classification scheme for Clark nevi proposed by Hofmann‐Wellenhof and differentiated between 12 different types of Clark nevi. Results: The most common type of Clark nevus was the reticular‐homogenous type (n = 64, 23,9 %), followed by the globular‐homogeneous type (n = 32, 12 %) and by the homogenous type (n = 30, 11,2 %). The overall inter‐rater agreement between the examiners was moderate to good (kappa = 0,58). The highest level of agreement was found for the peripheral hyperpigmented type (kappa = 0,83). Histologically, 17 lesions (6,3 %) were diagnosed as melanomas. The frequency of melanoma was highest among the peripheral‐hyperpigmented type for one observer and among the homogenous type for the other observer. No melanoma was found among the globular, reticular‐globular, and the central‐hyperpigmented types. Conclusions: A dermatoscopic classification of Clark nevi is practically feasible and allows – to some extent – a risk stratification of Clark nevi, which could be useful for clinical management.     

Cognitive deficits among functionally psychotic patients: a rehabilitative perspective

Psychological and neuropsychological assessments of psychiatric patients are usually designed to contribute to or document psychiatric diagnoses. The present article suggests that reframing the task to focus on cognitive rehabilitation issues can contribute significantly to the treatment of the chronic patient. A test protocol is proposed and exemplary tests suggested.     

Highly oxygen-permeable copoly(methacrylate/siloxane)s with perfluoroalkyl ester groups

Basic materials for contact lenses were obtained by radical copolymerization of linear α,ω-bis(methacryloyloxy)-terminated oligo- and poly(dimethylsiloxane)s, methyl methacrylate and 2,2,3,3,4,4,4-heptafuorobutyl methacrylate. Oxygen permeabilities, contact angles and ball indentation hardness were determined.     

WHERE ARE THE GATES IN GAP JUNCTION CHANNELS?

1. In the formation and function of gap junction channels two types of gates ought to be discriminated: the docking gate and the channel gates proper. The docking gate is involved in the transformation of a closed hemichannel to a patent gap junction channel. By definition the trigger mechanism for this gate and maybe even the gate itself is contained within the extracellular loops of the gap junction proteins, the connexins. The channel gates proper determine the open and closed states of the complete gap junction channels. 2. Probing the docking gate by mutagenesis of connexins and by synthetic peptides indicates that this gate is the consequence of complex interactions between a large fraction of the amino acids comprising the extracellular loops. Probably both inter- and intra-molecular interactions are involved, and disulfide exchange may be entailed in the stabilization of the open and closed states. 3. Of the various effectors on the channel gate(s) the voltage effects have obtained the most scrutiny to date. The response of gap junction channels and hemichannels is diverse, the various channels respond differently to transjunctional and membrane potential. No equivalent to the S4 segment representing the voltage sensor in other voltage dependent ion channels is present in the connexin sequences, instead mutations in various segments of connexins have been reported to affect the voltage dependence of gap junction channels. To understand the complexity of voltage effects on gap junction channels, non-connexin peptides may need to be considered as voltage sensors or as modifiers thereof.     

Quantitative assessment of variables that influence soft-tissue electrovaporization in a fluid environment

Objectives. To evaluate the process of soft-tissue electrovaporization and to study variables that affect tissue clearance rates in a laboratory setting, in order to identify parameters that can optimize transurethral electrovaporization of the prostate.Methods. Fresh bovine skeletal muscle, equivalent in impedance and surface properties to the human prostate, was submerged in 3.3% sorbitol solution and electrovaporized with a grooved monopolar electrode attached to the weighted arm of a linear actuator. The effects of excursion rate, applied mechanical load, power setting, electrode configuration, and generator performance on the volume of tissue removed, were assessed.Results. Tissue removal increased significantly when electrode excursion rate was slowed from 25 to 15 mm/s (P <0.05) and then to 10 mm/s (P <0.05); when the load was increased from 20 to 50 g (P <0.005); and when dial power was increased from 120 to 150 W (P <0.01). Tissue removal was generator dependent. There was no significant difference between the Force 40 and the Force 2 (P > 0.4), but a new computer-controlled constant power output generator (Force FX) did significantly improve tissue vaporization at an equivalent power setting (P <0.005 and P <0.01, respectively). Tissue removal was also dependent upon electrode configuration, with the VaporTrode-Grooved Bar removing significantly more tissue than either an ungrooved roller bar of equivalent size or 2-mm smooth roller ball, respectively, both after a single pass (P <0.001 and P <0.05) and after five repeated passes (P <0.05 and P <0.005). The histologic depth of tissue thermal effect was less than 1 mm, but it was 38% greater for the VaporTrode-Grooved Bar (0.68 mm) than for the standard cutting loop (0.5 mm, P <0.01).Conclusions. Using a novel method to quantify tissue removal, we have demonstrated that electrode configuration, excursion rate, applied load, power setting, and generator performance are interdependent factors that influence the efficacy of the electrovaporization process in a fluid environment.     

Respiratory tract infections due to different rhinovirus serotypes and the influence of maternal antibodies on the clinical expression of the disease in infants.

Rhinoviruses were isolated from nasopharyngeal secretions of 49 children hospitalized because of severe respiratory tract infection. The isolates were typed using 90 type-specific antisera. No obvious relation between certain serotypes and the severity of illness was found. Serum samples were drawn from all children simultaneously with the nasopharyngeal secretions and screened for the presence of type-specific neutralizing antibodies. Children aged 1 week to 6 months had higher neutralizing antibody titers and revealed a lower degree of morbidity than older children. The decline of neutralizing serum antibodies with increasing age was correlated with a higher incidence of severe disease in those aged 7-12 months. Nevertheless, also in this age group children with mild clinical courses of disease were observed despite a low concentration or an absence of neutralizing serum antibodies. This indicates that not only neutralizing serum antibodies, but other factors also influence the clinical expression of RHV-induced disease.