The potential hazard of laser pointers.

We have examined 30 laser pointers that have been removed from the possession of accused persons by police in Scotland. An analysis has shown that 28 were Class 3B (European), with radiated power up to 9.3 mW. We have reviewed the relevance of these findings and this shows that they are potentially hazardous if viewed directly. Transient exposure is unlikely to cause long-term damage but prolonged exposure may cause permanent retinal injury. They may also cause dazzle, the consequences of which could be serious.

An evaluation of the flammability of five dental gloves.

OBJECTIVE: To assess the flammability of five brands of dental procedure glove. DESIGN: A total of ten gloves of each brand (Biogel-D, Premier Protectors, Roeko-D, Safeskin Satin Plus and Schottlander Low Allergy) underwent flammability testing. Five of these were tested as supplied (unwashed) and five following the application of the hand disinfectant Hydrex (washed). Each glove was stretched over a metal frame and the time to ignition, when exposed to a standardised butane flame, recorded. In addition, the thickness of each glove was also assessed by micrometer measurement. RESULTS: All the gloves tested ignited in less than 2.5 seconds. Two way analysis of variance revealed significant effects of glove type (P< 0.001) and treatment (P< 0.05), together with a significant interaction of these factors (P < 0.05), upon the ignition time. Washing Roeko-D gloves with Hydrex significantly (P< 0.01) retarded the ignition time compared with those in the unwashed state. Both the glove thickness and material type appeared to be related to ignition time. CONCLUSION: The work presented here demonstrates the acute and varying flammability of a range of dental procedure gloves. It should serve as a reminder to those who routinely use open flames whilst gloved of the dangers of this practice.

Muscle fatigue in some neurological disorders.

Fatigue of tibialis anterior (TA) was induced by repetitive electrical stimulation. Using this test, patients with upper motor neuron muscle weakness owing to multiple sclerosis (MS) and injuries to the spinal cord showed greater fatigability of their TA muscles, suggesting that the muscle fiber population changed toward that typical of fatigable motor units. During repetitive stimulation, in addition to the decrement in tension there was an increase in half-relaxation time of tetanic contractions at 40 Hz in both subjects and patients. The increase in half relaxation during repeated activity was greater in patients with MS and spinal cord injury than in healthy subjects, suggesting that the long-term inactivity affected the efficiency of the Ca2+ uptake mechanism of their muscle fibers. Thus long-term inactivity of patients with upper motoneuron dysfunction leads to increased fatigability of their muscles and exaggerates the slowing of muscle relaxation after prolonged exercise.

Computerized 24-hour esophageal pH monitoring: a new ambulatory technique using radiotelemetry.

A computerized telemetric system using a portable microprocessor receiving unit has been designed for clinical use in ambulatory 24-hour esophageal pH monitoring. The receiving unit can be used with either a pH-sensitive radiotelemetry pill or a standard intraesophageal pH probe. Esophageal pH data is collected under microprocessor control while the patient is in the usual home or work environment. Computerized plotting and analysis of the compiled pH data is performed at the conclusion of the ambulatory testing. The system has been successfully used in patients with symptoms of esophageal reflux and healthy volunteers with no symptoms. The development of a computer-based radiotelemetry system for prolonged monitoring of esophageal pH represents a substantial advance in existing investigational technology. It allows the use of new radiotelemetric techniques of esophageal pH recording with increased patient comfort and acceptance over a 24-hour ambulatory testing period. Microprocessor control of both data collection and analysis allows rapid interpretation of complex 24-hour esophageal pH tracings and greatly facilitates the performance of esophageal pH monitoring as a routine clinical investigation.