Brain metabolism and blood flow in acute cerebral hypoxia studied by NMR spectroscopy and hydrogen clearance.

We have developed a reliable, reproducible model of hypoxia in the gerbil. 1H and 31P NMR spectroscopy demonstrates that cerebral energy metabolism is very resistant to hypoxia. Cerebral blood flow (measured by hydrogen clearance) began to increase when the arterial oxygen tension (paO2) was reduced to 40-50 mm Hg, and there was no change in phosphorus metabolites or lactate until paO2 was below 40 mm Hg. In 50% of the animals lactate increased prior to any change in the phosphorus metabolites or intracellular pH, suggesting that 1H NMR may be more sensitive than 31P NMR at detecting hypoxic or ischaemic changes. The calculated rate of oxygen delivery at a time when phosphorus energy metabolism becomes impaired is similar in both hypoxia and ischaemia (ca 4mL/100 g/min). We suggest that the critical factor in ischaemia is the reduction in oxygen supply, rather than the accumulation of toxic metabolites, such as lactate.     

Wireless pH testing as an adjunct to unsedated transnasal esophagoscopy: the safety and efficacy of transnasal telemetry capsule placement.

OBJECTIVES: The introduction of 48-hour wireless pH testing offers clinicians a new alternative for the objective documentation of reflux. The success of transnasal wireless pH capsule placement has not been previously described. The purpose of this investigation was to describe our experience with transnasal wireless pH capsule placement. METHODOLOGY: All patients undergoing unsedated transnasal esophagoscopy and wireless pH capsule placement between January 1, 2003 and July 31, 2003 were prospectively evaluated. Data concerning patient tolerance, success of capsule placement and function, complications, and pH recordings were collected. RESULTS: During this time, 46 persons were evaluated. The mean age of the cohort was 52 years. Of the patients, 50% were male. The indications for the procedure were chronic cough (18/46), gastroesophageal reflux disease (18/46), and larygopharyngeal reflux (10). Of the procedures performed, 85% (39/46) were successful. Complications included epistaxis (2/46), laryngospasm (2/46), and vasovagal reaction (1/46). CONCLUSIONS: The transnasal placement of a wireless pH capsule is a safe and effective diagnostic adjunct to unsedated transnasal esophagoscopy.     

BOOK REVIEW

Book reviewed in this article: OLD AGE: A REGISTER OF SOCIAL RESEARCH 1985–1990. Ed by G. Crosby, Information Service, Centre for Policy on Ageing, UK, 1991.     

Nine Years of the Freebase Cocaine Epidemic in the Bahamas

Nine years after the beginning of the epidemic of freebase (crack) cocaine abuse in the Bahamas, this historical study was done to characterize the natural course of the epidemic and to estimate the effectiveness of control measures. The authors' data include the incidence of new cases at the only psychiatric hospital in the Bahamas and at the primary community psychiatric clinic in the nation. The Bahamian response included 1) demand reduction, 2) supply reduction, and 3) reduction of money laundering. The annual number of new cases of crack abuse presenting for treatment declined from 1987 to mid-1991 in both facilities, but in 1992 it began rising again in the inpatient setting only. The changes in recent years have been accompanied by an increase in violent crimes against persons, especially robberies. (American Journal on Addictions 1994; 3:14–24)     

Screening for Meares–Irlen sensitivity in adults: can assessment methods predict changes in reading speed?

Two methods of assessing candidates for coloured overlays were compared with the aim of determining which method had the most practical utility. A total of 58 adults were assessed as potential candidates for coloured overlays, using two methods; a questionnaire, which identified self-reported previous symptoms, and a measure of perceptual distortions immediately prior to testing. Participants were classified as normal, Meares-Irlen sensitive, and borderline sensitive. Reading speed was measured with and without coloured overlays, using the Wilkins Rate of Reading Test and the change in speed was calculated. Participants classified as normal did not show any significant benefit from reading with an overlay. In contrast, a significant reading advantage was found for the borderline and Meares-Irlen participants. Current symptom rating was found to be a significant predictor of the change in reading speed, however the previous symptom rating was not found to be a reliable predictor. These data indicate that the assessment of perceptual distortions immediately prior to measuring colour preference and reading speed is the most meaningful method of assessing pattern glare and determining the utility of coloured overlays.