Corneal sensitivity during the menstrual cycle.

Corneal sensitivity was determined in 5 women with regular menstrual cycles by means of a new aesthesiometer developed by Dräger. Throughout one menstrual cycle we measured corneal touch thresholds (CTT) daily and did serial determinations of urinary luteinising hormone and pregnanediol levels. CTT rose in 4 women with proved ovulation in the days before or on the day of ovulation, while corneal sensitivity remained unchanged in one anovulatory subject. We observed no changes in CTT prior to menstruation. The decrease in corneal sensitivity might be related to the preovulatory oestrogen peak.     

Integration of synaptic and intrinsic dendritic currents in cat spinal motoneurons

The results of recent studies designed to reveal some of the ‘rules’ governing the integration of synaptic and intrinsic dendritic currents in spinal motoneurons are reviewed. When two or more sources of synaptic input are activated concurrently, their combined postsynaptic effects on cat spinal motoneurons with ‘passive dendrites’ are generally equal to or slightly less than those predicted from the linear sum of their individual effects. However, for experimental preparations in which active conductances on motoneuron dendrites are enabled, instances of greater-than- or less-than linear summation can occur. Further, these studies demonstrate that the persistent inward currents that are generated by motoneuron dendrites provide an intrinsic source of excitatory drive that is larger than those associated with any of the individual synaptic input systems studied to date. Since these intrinsic depolarizing currents can be rapidly inactivated by a hyperpolarizing input, they are ideally suited to providing a major source of the alternating ‘drive’ to motoneurons during locomotion.     

The interpretation of test results

BACKGROUND: Dermatologists need to interpret an increasing number of research studies and diagnostic tests. Understanding the techniques for interpreting test results and making decisions based upon those tests represent important tools for decision making for both clinicians and researchers. OBJECTIVE: This article focuses briefly on the key parameters of diagnostic tests: sensitivity, specificity, prevalence, predictive values, likelihood ratios, and the concept of receiver-operating-characteristic (ROC) curves. A simple example is presented in a step-by-step manner. CONCLUSION: The principles of interpreting test results are easy to learn and applicable in daily clinical routine. Therefore, dermatologists should be familiar with the concepts outlined in this paper.     

Relevance of interrater agreement to violence risk assessment

This study considered whether assessments of violence risk in which 2 clinicians reach similar conclusions are more accurate than the conclusions of either clinician alone when their assessments disagree. One hundred ten physicians and 44 nurses estimated the probability of physical assault of 478 patients admitted to a short-term locked psychiatric inpatient unit. The level of assessed risk showed a substantial correspondence with the likelihood of later violence when the physician and nurse ratings were highly concordant. As the extent of agreement between the physician and nurse ratings decreased, the strength of the association between the risk assessments and the occurrence of violence decreased accordingly.     

Combining physostigmine with meperidine for sedation and analgesia during colonoscopy

BACKGROUND AND STUDY AIM: Opiate or benzodiazepine drugs are often used during colonoscopy, but they are associated with respiratory depression and prolonged recovery. Physostigmine, a tertiary anticholinesterase agent, is known to enhance analgesia and to reverse the central nervous system depressant effects of these drugs. This study compared the effect of giving meperidine alone with the effect of giving meperidine in combination with physostigmine in patients who were undergoing complete colonoscopy. PATIENTS AND METHODS: A total of 44 outpatients undergoing elective colonoscopy were randomly assigned to receive analgesia with either meperidine 0.5 mg/kg intravenously (group 1, n=24) or physostigmine 10 micrograms/kg intravenously, followed 5 minutes later by meperidine 0.5 mg/kg intravenously (group 2; n=20). The patients were assessed with regard to oxygen saturation, hemodynamic changes, pain perception and sedation scores, readiness to go home, and adverse effects. RESULTS: The group 1 patients' oxygen saturations consistently fell, both during the procedure and in the recovery period; in group 2, oxygen saturations remained stable throughout the procedure and recovery period (95.88%+/-0.99 vs. 98.15+/-0.99, P<0.001). Patients in group 2 reported lower pain perception scores during the procedure (measured using a visual analog scale) than patients in group 1 (1.46+/-0.31 vs. 1.75+/-0.41; F1,42=6.484, P<0.015) and were less sedated during recovery (F1,41=6.56, P<0.015). No significant differences were found between the two groups with regard to heart rate or arterial blood pressure. All patients in group 2 were ready to go home after 25 minutes in the recovery area; three patients in group 1 were not ready to leave at 25 minutes and left the facility after 60 minutes. Four patients suffered from minor side effects of physostigmine (sweating and nausea). CONCLUSIONS: Combining physostigmine with meperidine as preparatory treatment for patients undergoing colonoscopy prevents respiratory depression, improves analgesia, and shortens recovery time, with only mild side effects.