Early management of abdominal trauma: the role of diagnostic peritoneal lavage

This report reviews the contemporary value of diagnostic peritoneal lavage (DPL) in the assessment of abdominal trauma, and reports the methods and results of its application within one trauma centre (Washington Hospital Center). DPL was reserved for those patients where doubt existed as to the presence of intra-abdominal injury, and gave a very accurate assessment of intraperitoneal injury. The complication rate was 0.4% and the accuracy of DPL was 97.7%. Except for laparotomy, DPL is the most sensitive indicator of haemoperitoneum available. It was first introduced with the aim of reducing the number of missed diagnoses of abdominal injury and it performs this task excellently when a low threshold for positivity is used. The open technique is safest and gives fewer false positive results, and the colorimetric method of analysis of lavage fluid is recommended, with strict adherence to advised criteria for negativity. A clinical algorithm is described, utilizing DPL, aimed at early diagnosis of all intra-abdominal injuries. This was extremely sensitive and failed in only one case in 384 (0.3%). The attendant, non-therapeutic laparotomy rate was 19%, and is regarded as acceptable within the aims of early diagnosis. In this series, there was no mortality or morbidity attached to the use of DPL or from non-therapeutic laparotomy, and there was only one delayed diagnosis in the entire series. No bowel, bladder, diaphragmatic, duodenal or pancreatic injuries were missed or diagnosed late.     

Effects of different cellulose derivatives on drug release mechanism studied at a preformulation stage.

As a matter of fact, in vitro dissolution is well known to be the method of choice for the pharmaceutical industry to develop effective medicines. However, many experiments must be performed all along a new product life and they represent an overcharge of work for researchers. The purpose of this paper was to assess the relevance of new parameters obtained during preformulation stage by Nuclear Magnetic Resonance (NMR) experiments to better understand drug release mechanism. This study was carried out with three cellulose derivatives currently used as carrier matrices (Microcrystalline cellulose (MCC), Hydroxypropylmethyl cellulose (HPMC) and Ethyl cellulose (EC)). Granules and tablets were produced with these three excipients (60% w/w) and theophylline as drug model (40%). On the one hand, in vitro dissolution studies were performed with the rotating paddle method displaying the different release behaviour of these three matrices (immediate release for MCC, steady release for HPMC and sustained release for EC). On the other hand, the evolution of the T2m spin-spin relaxation time in NMR experiments during granules hydration was recorded. NMR findings shore up dissolution data, both depending on interactions between the matrix and water. NMR spectroscopy appears to be a valuable tool for obtaining, at an earlier stage of drug development, more information about drug release mechanism.     

Allodynia in rats infected with varicella zoster virus—a small animal model for post-herpetic neuralgia

The most common complication of herpes zoster is post-herpetic neuralgia (PHN), which has been defined as severe pain occurring 1 month after rash onset or persisting for greater than 3 months. PHN is classed as a neuropathic pain that is associated with mechanical allodynia where normally innocuous tactile stimuli are perceived as painful. The development of therapies to treat PHN has been hampered by the lack of animal models, which mimic the clinical situation. We have previously reported that varicella zoster virus (VZV) infection in the rat results in mechanical allodynia and thermal hyperalgesia. Here, we report that following VZV infection of the left footpad rats develop a chronic mechanical allodynia, which is present for longer than 60 days post-infection and which resolves by 100 days PI. The model is robust and reproducible with animals consistently developing allodynia by 3 days PI and continuing to present with symptoms for at least 30 days. The reproducible nature of the induction and course of the allodynia allows the use of this model to determine the effect of various compounds on, and to investigate the pathogenic mechanisms underlying the development of VZV-induced allodynia. Comparative studies using HSV-1 show that the induction of the chronic allodynia is VZV-specific and is not a result is of virus replication-induced tissue damage or accompanying inflammation.Therefore, we propose that the rat VZV infection model could prove useful in studying the mechanisms underlying post-herpetic neuralgia.