The Dynamic Behavior of the Diastolic Slope of Monophasic Action Potential Can be Related to the Occurrence and Maintenance of Delayed Afterdepolarization Dependent Arrhythmias

We have described the value of the diastolic slope of the MAP recording at the end of a pacing train as a qualifying marker for the induction of delayed afterdepolarization (DAD) dependent arrhythmias. In the present study (1) the behavior of the slope at different time points during a pacing train was quantified and related to the arrhythmogenic outcome (group A) and (2) termination of DAD dependent VT was related to changes in the slope steepness (group B). In dogs with chronic complete AV block, a MAP was recorded during (1) ventricular pacing, before and after ouabain administration (group A) and (2) 6 spontaneous and 6 lidocaine induced VT terminations (group B). During control (group A), the slope at the end of pacing train was 5 ± 3 mV/s (mean ± SD), independent of the pacing duration. During ouabain, this increased to 20 ± 15 mV/s (P < 0.05), varying with the duration of pacing. The slope was steeper after pacing for 4 seconds, compared to 20 seconds (26 ± 12 mV/s vs 16 ± 13 mV/s, P < 0.05) which corresponded with more frequent VT induction. In spontaneously terminating VTs (group B), CL increased from 353 ± 54 ms at the start to 434 ± 78 ms (P < 0.05) before VT termination. This corresponded with a decreasing steepness of the slope from 19 ± 10 mV/s to 6 ± 5 mV/s (P < 0.05). In lidocaine induced VT termination, the CL and the steepness of the slope showed an identical behavior. There is a dynamic variation in the steepness of the diastolic slope during pacing, which depends on the duration of pacing and predicts arrhythmogenic outcome. Furthermore, a decrease in steepness of the slope during DAD dependent VT can be used to predict VT termination.     

Down to the Wire: Tricuspid Stenosis in the Setting of Multiple Pacing Leads

Tricuspid stenosis in the setting of endocardial pacing leads is a rare entity, attributed to infection or lead malposition. We report the case of a 37‐year‐old man without these risk factors, who presented with new onset severe tricuspid stenosis in the setting of multiple chronic pacing leads. (PACE 2010; e49–e52)     

CYCLIN D1 OVEREXPRESSION IN NON-SMALL CELL LUNG CARCINOMA: CORRELATION WITH Ki67 LABELLING INDEX AND POOR CYTOPLASMIC DIFFERENTIATION

Cyclin D1 is part of the molecular system regulating the cell cycle G1 to S transition point. Its overexpression, a common finding in carcinomas of the breast, oesophagus, and head and neck, has also been demonstrated in a high percentage of non-small cell lung carcinomas (NSCLCs). The role of cyclin D1 in NSCLC has been studied by correlating its immunoreactivity with the Ki67 labelling index in paraffin-embedded, autoclaved surgical samples of 56 NSCLC cases. In addition, flow cytometric determination of ploidy and cell cycle status was carried out on 172 fresh tumour samples from the same cases. Twenty-four (42·8 per cent) NSCLCs showed positive cyclin D1 immunostaining, a finding which showed no relationship to ploidy pattern, cell cycle phase, histological subtype, or lymph node metastasis, but was significantly associated with the Ki67 labelling index ( P =0·03) and with poor cytoplasmic differentiation ( P =0·01). Cyclin D1-positive nuclei were abundant in poorly differentiated zones and absent in the best differentiated areas, particularly in heavily keratinized fields. These data indicate that in NSCLC, cyclin D1 overexpression is not only associated with a high cell proliferation rate, but also seems to play a role in the process of tumour differentiation.     

The effects of corticosteroid administration before preterm delivery: an overview of the evidence from controlled trials

Summary. Continuing differences of opinion among obstetricians and neonatologists about the place of corticosteroid administration before preterm delivery have prompted us to carry out a systematic review of the relevant controlled trials, using methods designed to minimize systematic and random error. Data from 12 controlled trials, involving over 3000 participants, show that corticosteroids reduce the occurrence of respiratory distress syndrome overall and in all the subgroups of trial participants that we examined. This reduction in respiratory morbidity was associated with reductions in the risk of intraventricular haemorrhage, necrotizing enterocolitis and neonatal death. There is no strong evidence suggesting adverse effects of corticosteroids. The risks of fetal and neonatal infection may be raised if they are administered after prolonged rupture of the membranes, but this possibility is not substantiated by the results of the available trials. The available data on long-term follow-up suggest that the short-term beneficial effects of corticosteroids may be reflected in reduced neurological morbidity in the longer term.     

Family,school, delinquency and criminality,the predictive power of an elaborated social control theory for males

The developmental paradigm of the criminal career implies that different factors, among a particular set of control theory variables, may support adolescent delinquency and adult criminality. In this paper we use a large set of family and school control theory variables, measured during early and late adolescence, to predict late adolescent delinquency and adult official and self-reported criminality. To do so, we use a representative sample of male adolescents and multiple regression. When 18 family and 19 school variables are combined to predict adult criminality, only three remain highly significant, in the following order: school performance, attachment to parents and adolescent delinquency. Late adolescent delinquency accounts for a higher proportion of explained variance than adult criminality (36% versus 22% for official and 29% for self-reported criminality). For the prediction of adolescent delinquency, the variables are, in the following order: previous self-reported delinquency, school performance and family bonding. Some variables, such as school performance and parental attachment, have a long-term impact on adult offending but others, such as deviant behaviour, demonstrate a situational impact on adolescent delinquency. On the basis of these results, a lifespan control theory of adult criminality is proposed.     

High Atrial Pacing Impedance: Efficient or Wasteful? A Comparison of an Active and a Passive Fixation Lead

We compared the stimulation characteristics of two atrial fixation leads: the CPI model 4269 (n = 45) and Cordis-Telectronics model 327–752 (n = 42). The CPI lead uses an active fixation method, whereas the Cordis-Telectronics lead is fixated passively. Impedance and threshold were measured at implant and during 12 months of follow-up. P wave sensing was good with both types of leads. Follow-up of these 87 leads showed that both the impedance and threshold increased with the active leads, but not with the passive fixation leads. In the active fixation group, regardless of the high atrial pacing impedance, 93% could still be programmed to 2.5 V-0.6 msec (with a 2:1 threshold safety margin). It is concluded that the high chronic pacing impedance of the active fixation leads will be beneficial on current drain if no major increase in pacing threshold occurs simultaneously.     

Evaluation of the Inhibitory Activity on Serine and Aspartic Proteases of 4-Amino-4H-1,2,4-triazole and 5-Aminothiazole Derivatives Structurally Related to β-Lactam Antibiotics

Abstract— Twenty new derivatives of 4-amino-4H-1,2,4-triazole and 5-aminothiazole have been examined for their inhibitory potential towards serine and aspartic proteases. Upon prolonged incubation with enzyme, the phenylacetylaminothiazolium salts exhibit progressive, time-dependent inhibition of chymotrypsin according to a first-order process. The formation of a tetrahedral transition state-like complex by attack of the active-site serine at the C2-position of the pseudobase form of the thiazolium may be responsible for the observed effect. Triazolium salts appeared to be simple competitive inhibitors of this enzyme, effective in the Mm range concentration. Poor inhibitions of trypsin and pepsin were also obtained in the triazolium series. In spite of their structural analogy with β-lactams, the selected derivatives failed to inhibit human leucocyte elastase.