Mapping molecular binding by means of conformational dynamics measurements

Protein–protein interactions are key in virtually all biological processes. The study of these interactions and the interfaces that mediate them play a key role in the understanding of biological function. In particular, the observation of protein–protein interactions in their dynamic environment is technically difficult. Here two surface analysis techniques, dual polarization interferometry and quartz crystal microbalance with dissipation monitoring, were paired for real-time mapping of the conformational dynamics of protein–protein interactions. Our approach monitors this dynamics in real time and in situ, which is a great advancement within technological platforms for drug discovery. Results agree with the experimental observations of the interaction between the TRIM21α protein and circulating autoantibodies via a bridging bipolar mechanism. This work provides a new chip-based method to monitor conformational dynamics of protein–protein interactions, which is amenable to miniaturized high-throughput determination.

Protein–protein interactions are key in virtually all biological processes.     

Thoracoscopic surgery in elderly lung cancer patients

Age is a recognized risk factor for death after thoracotomy in elderly patients with lung cancer. Among other factors, the genesis of this risk is the physiologic debilitation that occurs after division of the intrathoracic respiratory muscles during thoracotomy, as well as the loss of lung tissue after lung resection. Recent advances in video-assisted thoracic surgery (VATS) techniques provide an alternative to standard thoracotomy in elderly lung cancer patients, resulting in decreased recovery times and fewer perioperative complications. Likewise, smaller lung resections (VATS-guided limited wedge resection versus lobectomy with thoracotomy) can be adequate oncologic procedures in patients with a limited life expectancy but resectable disease. We studied these alternative procedures in a cohort of thoracic surgical patients at the Brigham and Women's Hospital in Boston, MA. Proposed investigations of the psychosocial implications of thoracic surgery in the elderly, irrespective of the safety of these maneuvers, are addressed.     

Selective stimulation of colonic motor response to a meal by sigma ligands in dogs

The influence of central vs. peripheral administration of sigma ligands (dl- and l-N-allylnormetazocine, 1-3-di-o-tolylguanidine, (+) cinnamyl-1-phenyl-1-N-methyl-N-cyclopropylene and phencyclidine on colonic motility was investigated in fasted and fed dogs equipped with strain-guage transducers implanted on proximal and transverse colon. When injected intravenously at a dose of 0.25 mg/kg just before feeding, dl- or d-N-allylnormetazocine, 1-3-di-o-tolylguanidine, and (+) cinnamyl-1-phenyl-1-N-methyl-N-cyclopropylene (but not phencyclidine) enhanced the colonic motor response to a meal by increasing the 0-4-hour motility indexes from 64.1%-159.3% in both the proximal and transverse colon but had no effect on colonic motility in fasted animals or animals injected intracerebroventricularly. The motor-stimulatory effects of d-N-allylnormetazocine (1 mg/kg), 1-3-di-o-tolylguanidine (0.25 mg/kg), and (+) cinnamyl-1-phenyl-1-N-methyl-N-cyclopropylene (1 mg/kg) were abolished after previous treatment with haloperidol (0.5 mg/kg, intravenous) but not after sulpiride (0.1 mg/kg) or (+) R-(+)-8-chloro-2,3,4,5-tetrahydro-3- methyl-5-phenyl-1-H-3-benzozepine-OH. Prazosin (0.1 mg/kg, intravenous) and 1-methyl-3-(2-indolyl)amino-5-phenyl-3H-1,4-benzodiazepin-2-one (0.01 mg/kg) also suppressed the enhancement of the colonic motor response to eating induced by d-N-allylnormetazocine, 1-3-di-o-tolylguanidine, and (+)cinnamyl-1-phenyl-1-N-methyl-N-cyclopropylene whereas naltrexone did not affect their effects. It is concluded that d-N-allylnormetazocine, 1-3-di-o-tolylguanidine, and (+)cinnamyl-1-phenyl-1-N-methyl-N-cyclopropylene stimulate the postprandial colonic motility in dogs by acting selectively on sigma receptors located peripherally and probably by affecting the release of cholecystokinin octapeptide through a central adrenergic mechanism.     

Influence of acoustic stress by noise on gastrointestinal motility in dogs

The effects of acoustic stress (AS) on gastrointestinal motility and their prevention by previous treatment with naloxone, phentolamine, propranolol, muscimol, and diazepam were investigated in intact and vagotomized fasted dogs fitted with chronically implanted strain gauges on the antrum at 10 cm from pylorus and on the jejunum at 70 and 140 cm from the pylorus. These effects were compared to those produced by intracerebroventricular administration of ovine corticotropin releasing factor (oCRF). Beginning 40–50 min after the occurrence of a gastric migrating motor complex (MMC), a 1-hr hearing of prerecorded intense music through earpieces (<100 dB) delayed the occurrence of the next gastric MMC observed after 2.8±1.2 hr, while jejunal MMC were still present at a normal frequency. During AS, heart rate and plasma cortisol were significantly increased by 32.7 and 215%, respectively, 10–15 min after the beginning of hearing. The AS-induced lengthening of the gastric MMC cycle as well as cortisol increase were abolished after previous administration of diazepam (0.5 mg/kg intramuscular) or muscimol (10 g/kg intravenous), while they were still present after naloxone (0.1 mg/kg intravenous), phentolamine (0.2 mg/kg intravenous), or propranolol (0.1 mg/kg intravenous). CRF administered intracerebroventricularly (100 ng/kg) also delayed the occurrence of gastric MMC without affecting jejunal motility, and this effect was not antagonized by previous treatment with diazepam or muscimol. Both the effects of AS and CRF were abolished after bilateral thoracic vagotomy. These results suggest that the selective inhibition of gastric motility induced by noise in dog is due to the CNS release of CRF which affects, in turn, the vagal output to the stomach. The suppressive action of diazepam or GABA agonist on noise-induced gastric hypomotility may be related to blockade of the AS-induced CRF release.     

Irritable bowel syndrome in France: a common, debilitating and costly disorder

OBJECTIVE: This epidemiological investigation aims to measure the prevalence of irritable bowel syndrome (IBS) in the general population using the Rome II criteria and to evaluate the medical management including treatments and the impact of IBS on patient life. METHODS: A nationally representative sample of 20,000 French subjects, aged 18 years and over, were interviewed by SOFRES (French Public Opinion Poll Institute) in May 2001. In a second phase (June/July 2001), a 48-question self-administered questionnaire was given to the subjects who have been selected during the first phase as suffering from IBS (Rome II criteria). RESULTS: The prevalence of IBS was 4.7% (confidence interval, 4.36-5.04% with 5% risk) with a predominance in women (5.7% versus 3.7%, P < 0.01). The abdominal pain was often longstanding (> 5 years, 50%), intense (43%) and nocturnal (35%). During the most recent painful episode the levels of associated transit problems were almost equally divided between diarrhoea (36%), constipation (29%) and alternate episodes of both (31%). Apart from pain, bloating was given as the most frequent (73%) and most troublesome (24%) symptom. Since the onset, 80% of subjects with IBS had consulted a doctor (90% consulted a general physician, 57% a gastroenterologist, 50% both) and of these, 80% consulted within the previous 12 months. Sixty-seven per cent of subjects underwent additional investigations since the start of their illness (average of 3.4 examinations per patient examined: colonoscopy, 34.1%; laboratory tests, 34%; and abdominal ultrasound, 27.7%). Over the previous 12 months, 8% of the subjects had been admitted to hospital (average length of stay, 6.6 days), 11% of employed subjects had to take time off, 93% of subjects had taken prescribed medication (87%), but 43% of people thought it was ineffective. The effect on daily life was considerable (score, 6.2/10; close to the score for flu, 7/10). Two-thirds of the individuals changed their diet; 54% said it affected their social life and 29% their professional life. Seventy-four per cent of patients trusted their doctor, with a satisfaction index of 63%, but 45% of patients would like to have more information on IBS. CONCLUSION: This study confirmed that the Rome II criteria detected IBS with a prevalence of 4.7%. The recruited subjects had severe symptoms (frequency, intensity and duration) that had a considerable effect on their daily life. The high level of referrals and initial consultations in all categories and the patient's attitudes towards the illness and its treatment emphasize the relative ineffectiveness of care for patients suffering from IBS.     

Impact of scatter on double-pass image quality and contrast sensitivity measured with a single instrument

We compared objective Double-Pass (DP) image quality data with subjective visual parameters measured within the same modified instrument for different amounts of scatter. The original DP imaging channel of a clinical instrument was maintained intact and two additional channels were included, one for visual testing and another for tear film (TF) imaging by using a retro-illumination technique. Contrast sensitivity (CS) was compared with measurements of the Objective Scattering Index (OSI) obtained from DP retinal images corresponding to different scatter levels induced by pre-defined filters. OSI values were correlated with the change in CS for different spatial frequencies measured with the same instrument. Since TF and DP images were recorded at the same rate, this provided additional information about the dynamic spatial stability of the tear film. This new DP instrument has been proven to provide accuracy and repeatability, and to be suitable for clinical diagnosis, with a complete evaluation of the eye’s performance by a simultaneous objective and subjective assessment under the same experimental conditions.OCIS codes: (330.4460) Ophthalmic optics and devices, (330.7327) Visual optics, ophthalmic instrumentation     

Rentabilidad del estudio genético mediante técnicas de next-generation sequencing masiva de pacientes con miocardiopatía arritmogénica de alto riesgo

Introduction and objectives

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by progressive fibrofatty replacement of predominantly right ventricular myocardium. This cardiomyopathy is a frequent cause of sudden cardiac death in young people and athletes. The aim of our study was to determine the incidence of pathological or likely pathological desmosomal mutations in patients with high-risk definite ARVC.