Conduction velocity during the supernormal and late subnormal periods in human nerve fibres

Zusammenfassung An die relative Refraktärperiode schließt sich eine supernormale Phase an und daran wiederum eine späte subnormale Phase. Die Wirkung dieser beiden letzten Phasen auf die Leitgeschwindigkeit wurde an sensiblen Nervenfasern untersucht. 80% der Untersuchten zeigten während der supernormalen Phase (4–10 msec nach der ersten Aktivierung) eine Beschleunigung der Leitgeschwindigkeit auf 106% des Normwertes. Die Beschleunigung ist weniger ausgeprägt, wenn die Gewebstemperatur erniedrigt ist. Bei 65% der Versuchspersonen wurde eine Verzögerung der Impulsfortleitung während der subnormalen Phase (10–100 msec nach voraufgegangener Aktivierung) beobachtet. Die Veränderungen der Leitgeschwindigkeit laufen zu den bekannten Veränderungen der Membranerregbarkeit parallel.     

Radiofrequency modified maze procedure for chronic atrial fibrillation

Background We studied the effectiveness of Radiofrequency (RF) modified maze in early and late restoration of sinus rhythm in patients with rheumatic heart disease (RHD). Methods We studied 84 patients with RHD over 23.6±12.5 months after the RF modified maze and another group of 64 patients over six months after valvular surgery alone (the Non-Maze group). Any thromboembolic episodes and NYHA class of the patient were recorded. The short term survivors in sinus rhythm, underwent stress test and echocardiography for atrial transport function at 3–6 months after surgery. Results In the Maze group, sinus rhythm was restored in 60/70 patients (85.71%) immediately and sustained in 55/70 patients (78.57%) over the follow-up as against an immediate conversion rate of 5.3% (5/53 patients, p<0.001) in the Non-maze group. The additional Cardiopulmonary (CP) bypass time (p=0.13) and cross clamp time (p=0.511) needed for maze is not statistically significant. Left atrial (LA) transport function was preserved in 41/51 patients (80.4%) and Right atrial (RA) transport function in 51/51 patients (100%). Stress test showed good chronotropic response in all the 41 patients in whom it was performed. In the Maze group one patient presented with acute valve thrombosis and subsequently, succumbed to it. In the non maze group 3/55 patients (5.66%) were hospitalized for stroke. No patient needed permanent pacemaker nor was sinus node dysfunction seen. The immediate postoperative morbidity and mortality was comparable in the two groups. Conclusions The RF modified maze is safe, effective and brief without any additional risk. It restores sinus rhythm in the majority, however there is an attrition in some.     

Performance characteristics of a glycoprotein G based oligopeptide (peptide 55) and two different methods using the complete glycoprotein as assays for detection of anti-HSV-2 antibodies in human sera

Assays for serological diagnosis of HSV-2 infection in clinical settings have been generally available only recently. We wanted to investigate and compare the diagnostic utility of three different ELISAs for detection of anti-HSV-2 IgG antibodies, using intact glycoprotein G or an oligopeptide from a portion of the protein as antigens. HSV-1 negative/HSV-2 negative sera (n = 32), HSV-1 positive/HSV-2 negative sera (n = 30) and sera from HSV-2 culture positive individuals (n = 36), collected at least 6 months after culture verified HSV-2 genital infection were examined. Cut-off values were determined according to the manufacturer's instructions, and also by establishing new cut-off values at the level of highest diagnostic efficiency. Sensitivities and specificities were compared for each assay. In addition, test accuracies were compared using receiver-operating characteristics (ROC) methodology. Establishment of new cut-off values increased the performance characteristics for all three tests. At similarly set cut-off values, the peptide 55 assay showed the highest diagnostic sensitivity (100%) and specificity (98%). All three assays displayed high efficiency and also high agreement between the tests (kappa > 0.85 for all comparisons). The performance of all three assays were satisfactory although the highest efficiency and accuracy was obtained with the peptide 55 assay.     

Sigmoid colon perforation with local peritonitis caused by indirect trauma--case report and review of the literature

Injuries to the sigmoid occur either as acute or protracted events. In the first case, enteral contents discharge into the abdominal cavity and a generalized, fecal, life-threatening peritonitis with a bad prognosis develops. In the protracted form, the rupture is covered by peritoneum and adherent organs before perforation.The ensuing abscess formation may lead to perforation into contiguous visceral organs or the cutis. Frequently an intestinal or cutaneous fistula results. The trigger for a sigmoid perforation can be a spontaneous rupture in an already vulnerable intestine. Common precursory diseases are diverticulitis, colitis, carcinomas, and necroses. Also, elevated intestinal pressure invoked by increased bearing down or coproliths may cause disruption. Diagnostic procedures such as rectoscopy and rectal contrast instillation are frequent idiopathic causes of traumatic injuries to the sigmoid. Perforating injuries of the abdominal cavity by stabbing, gunshot, or impalement may affect the sigmoid and open its lumen. Foreign bodies often lead to traumatic injuries of the rectosigmoid junction. In contrast, indirect trauma as a cause of sigmoid perforation, which is described in the following case, is very rare. A 62-year-old woman,who had a cholecystectomy and adhesive strangulation of intestine in her history, was admitted to our clinic after falling down stairs and landing on her bottom. She suffered a sigmoid rupture and peritonitis.Laparotomy and suturing of the sigmoid defect were performed.     

Nitric oxide synthase (NOS-1) coclustered with agrin-induced AChR-specializations on cultured skeletal myotubes

Previously we reported that neuronal nitric oxide synthase type-1 (NOS-1) is expressed in skeletal myotubes in vitro. In the present paper we sought to determine whether agrin-induced membrane specializations known to include the nicotinic acetylcholine receptor (AChR) on cultured myotubes may also contain NOS-1 and related molecules. After treatment with various agrin constructs containing the full C-terminally AChR-clustering domain (fragments N2, N4), but not with fragment C2 (truncated), NOS-1 expressed in the cytosol of mouse C2C12 skeletal myotubes coclustered with AChR, 43K rapsyn, MuSK, and the dystrophin/utrophin glycoprotein-complex (DUGC). Agrin-induced specializations also included coaggregates of N-methyl-d-aspartic acid (NMDA)-receptor, alpha-sodium (NaCh), or Shaker-type K+ channel (KCh)/PSD-95 complexes, and NOS-1. We conclude that agrin is crucial for recruitment of preassembled multimolecular membrane clusters, including AChR, NMDAR, and ion channels linked to NOS-1. Coassembly of NOS-1 to postsynaptic molecules may reflect site-specific NO-signaling pathways in neuromuscular junction formation and functions.     

Effects of food on the pharmacokinetics of levodopa in a dual-release formulation.

The objective was to assess the effect of food on the pharmacokinetics of levodopa and 3-O-methyldopa after administration of a new levodopa/benserazide formulation with a dual-release drug delivery profile (Madopar DR). In an open-label, two-way cross-over study, 19 healthy volunteers who had fasted overnight were randomized to receive a single oral dose of levodopa/benserazide (200/50 mg) in the absence or presence of a standardized, high-fat breakfast, administered 30 min before drug administration. The treatment periods (fasting, non-fasting) were preceded by a baseline regimen of levodopa/benserazide (100/25 mg t.i.d. for 6 or 7 days). Blood samples were taken at specific times over a 12-hour period. Plasma concentrations of levodopa and 3-O-methyldopa were determined by high-performance liquid chromatography for pharmacokinetic evaluation. The parameter C(max) of levodopa was significantly lower and t(max) longer under postprandial conditions than under fasting conditions (mean C(max) 1.41 vs. 2.09 mg l(-1); mean t(max) 3.1 vs. 1.0 h). With food, the area under the curve (AUC) of levodopa was equivalent to that following an overnight fast. Compared with volunteers who had fasted, food did not alter t(1/2). Estimates of C(max), t(max) and AUC of 3-O-methyldopa under non-fasting conditions were not significantly different from those under fasting conditions. In conclusion, food decreases the rate of levodopa absorption, but had no effect on the systemic exposure to levodopa and the degree of 3-O-methyldopa formation. Standardization of levodopa/benserazide administration with respect to meal times is recommended.