Local anaesthesia in elective inguinal hernia repair: a randomised, double-blind study comparing the efficacy of levobupivacaine with racemic bupivacaine.

OBJECTIVE: To assess the use of infiltration with local anaesthetics levobupivacaine and bupivacaine, during inguinal hernia repair. DESIGN: Double-blind, randomised study. SETTING: Postgraduate medical school, United Kingdom. SUBJECTS: 69 male patients aged 18 years or older. INTERVENTIONS: Wound infiltration with 0.25% levobupivacaine and 0.25% racemic bupivacaine. MAIN OUTCOME MEASURES: Area under the curve (AUC) of visual analogue scale (VAS) scores for postoperative pain at rest in the supine position, rising from the supine to the sitting position, and walking, against time for both treatment groups. RESULTS: There were no significant differences between treatment groups for the AUC of VAS scores for postoperative pain, global verbal pain rating or time to first dose of analgesic medication. CONCLUSIONS: Levobupivacaine exerts a similar anaesthetic and analgesic effect to racemic bupivacaine when infiltrated both intraoperatively and during the early postoperative period for elective inguinal hernia repair.     

Nitrates do not affect prostacyclin formation by rat arteries: this is unrelated to increased vascular prostacyclin formation with age

The question of whether vasodilator nitrates act by releasing prostacyclin is controversial. Since the ability of blood vessels to form prostacyclin changes with age, we have investigated whether this may explain the discrepancies in the literature. It does not, since isosorbide dinitrate or glyceryl trinitrate incubated with rat aorta or vena cava from male Wistar rats had little or no effect on the release of prostacyclin, measured as 6-keto-PGF1 alpha. We confirm that the aorta produces substantially more prostacyclin than the vena cava. The arterial production of prostacyclin was greater in rats weighing 350-400 g than in those weighing 116-152 g, but the production by the veins was similar in both groups.     

Statistical analysis of categorical data

This article has presented the most widely used techniques for analyzing categorical data. Data that are qualitative are naturally categorical. Even continuous (or measurement) data can be classified into categories (eg, ages can be grouped into above and below 40) and, hence, these procedures can be applied to a wide range of data. All of these statistical tests are classified as nonparametric statistics, although many statistical textbooks treat hypothesis testing of categorical data separately from the more common nonparametric methods. The most widely used nonparametric procedures will be reviewed in the next issue.     

Mohs micrographic surgery for skin cancers of the neck

The neck is not a common area for a skin cancer to occur. However, when it does occur and extends deeply, careful extirpation is necessary so that vital structures will be identified and, if possible, preserved. The Mohs surgeon can most accurately determine the true extent of malignancies in this area; the head and neck surgeon can best identify and protect important anatomic structures. Together both physicians can achieve the best chance of cure and lessen the complication rate for patients with selected invasive cutaneous tumors of the neck. Future collaborative efforts will undoubtedly be directed toward complete extirpation of deeper tumors of the neck, especially those of the pharynx, hypopharynx, and trachea.     

Schedule-controlled brain self-stimulation: Has it utility for behavioral pharmacology?

We review evidence that schedule-controlled intracranial self-stimulation (ICSS) has properties in common with conventional reinforcements, such as food and water, but unlike the latter, animals will respond for ICSS for long periods of time at a near-constant rate. Schedule-controlled ICSS has proven to be more sensitive to drug-induced changes than has ICSS on a continuous reinforcement schedule, and it permits a more fine-grained analysis of the pattern of responding that results in the reinforcement. Evidence is accumulating that the schedule of ICSS itself leads to neurochemical changes in areas of the brain, such as the nucleus accumbens, in which reward processes occur. Results obtained from schedule-controlled ICSS would complement those obtained by drug self-administration studies which generally use intermittent reinforcement. A systematic examination of ICSS schedules at different brain sites would greatly facilitate our interpretation of drug effects and this would have utility for behavioral pharmacology.     

Brain and kidney of progressive multifocal leukoencephalopathy patients contain identical rearrangements of the JC virus promoter/enhancer

The kidneys of six progressive multifocal leukoencephalopathy (PML) patients were examined by PCR amplification for the presence of JC virus. Amplification of three different areas of the viral genome from multiple samples of each kidney revealed three that were positive for the virus. The use of a PCR-based typing assay on all tissue samples, and cloned sequences from the viral coding region from each positive kidney showed that the same viral genome was present in the kidney as in the brain of the patient. Regulatory region clones all had the archetypal promoter/enhancer structure. However, when PCR fragments from the regulatory region were digested with a restriction enzyme which cuts in region D, the region most often deleted in PML-type promoters, a low level of undigested DNA remained. This DNA refractory to digestion had a rearranged sequence identical to that of the unique rearranged promoter in the brain of each patient. © 1994 Wiley-Liss, Inc.