The occupational risk to dental anesthesiologists of acquiring 3 bloodborne pathogens

OBJECTIVE: To estimate the occupational risk to dental anesthesiologists of contracting 3 bloodborne pathogens: hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV). METHODS: Through an anonymously returned, mailed questionnaire, dental anesthesiologists in Canada and the United States provided information regarding percutaneous and mucocutaneous contacts with contaminated fluid during the treatment of patients under deep sedation and general anesthesia as well as other general practice information. A mathematical model was applied to determine the occupational risk. RESULTS: Of the 101 (65%) returned questionnaires, 98 reported having treated patients within the previous 6 months. Of these, 41 (42%) had at least one percutaneous accident (89 accidents in total), and the projected mean annual injury rate for dental anesthesiologists overall was 1.82. The most common causes of injury were burs, intraoral needles, and dental instruments. Operator error during use was associated with 31% of reported accidents. Significantly more injuries were reported by those who also reported a mucocutaneous contact and by those working more than 25 hours per week. The projected mean annual number of mucocutaneous exposures was 0.88 for dental anesthesiologists overall. CONCLUSIONS: The calculated annual risk to the average dental anesthesiologist of acquiring HBV (if not immune), HCV, and HIV following percutaneous injury was very low for all infections (HBV the most; HIV the least). The risk of contracting HIV following mucocutaneous contact was extremely low.     

Channel properties determine the transient activation kinetics of recombinant GABA(A) receptors

To understand the mechanisms underlying activation and deactivation of GABA(A) receptor (GABAR) channels, we studied the properties of an identified GABAR isoform under conditions similar to those present at central GABAergic synapses. Recombinant alpha5beta3gamma2L GABARs were expressed in L929 fibroblasts and studied using patch-clamp recording techniques. Brief application of a high GABA concentration to outside-out membrane patches elicited transient currents that resembled those reported for miniature inhibitory postsynaptic currents (mIPSCs), as well as native GABAR currents recorded under similar conditions. Characteristic of these currents was a rapid activation phase followed by a prolonged biphasic deactivation phase that far outlasted GABA application. Single-channel recordings revealed unique patterns of channel activity with two channel conductance states of 22 and 16 pS. The prolonged deactivation phase appeared to be sustained by entry into and reopening from long-lasting closures or desensitized states. Agonist affinity determined the time course of deactivation, indicating that occupied receptors drove the channel activity underlying the decay of current. The time course of deactivation was also longer at depolarized membrane potentials. The similarities between transient activation kinetics of recombinant alpha5beta3gamma2L GABARs to activation of synaptic GABARs (rapid activation and prolonged, voltage-dependent deactivation) suggest that intrinsic channel properties determine much of the response patterns of native GABARs.     

Trends and geographical disparities in coronary heart disease in France: are results concordant when different definitions of events are used?

OBJECTIVES: To assess whether different definitions of acute coronary events yielded concordant results concerning trends and geographical disparities in coronary heart disease (CHD) mortality and morbidity in France. STUDY DESIGN: Data from three French CHD registries participating in the WHO MONICA Project during the period 1985-1992. SETTING: Three areas of about one million inhabitants each in the North, South and East of France. SUBJECTS: About 2,000 acute coronary events each year. MAIN OUTCOME MEASURES: Mortality, annual rate of fatal and non-fatal events, incidence of first and recurrent events, case-fatality rates. RESULTS: For incidence and mortality, the broader the broader the definition of the acute event, the higher the reported rates. The same tendency was not observed for case-fatality rates. Comparing between-registry rates for mortality, 28-day case-fatality and hospital case fatality yielded relatively concordant results whatever the definition of event. As a whole, the higher mortality rate in Lille and its intermediate rank in Strasbourg were related more to disparities in case-fatality rates, with only small variations in incidence rates, independently of the definition used. Comparing temporal trends in rates within and between regions, a consistent decrease in annual mortality rates and case-fatality rates was observed, whatever the definition. In contrast, the incidence of non-fatal probable myocardial infarction did not change during the period in any register. CONCLUSIONS: Although the absolute estimates of rates were variable with the definition of the event, major findings in relation to trends and geographical disparities were fairly consistent across the definitions: the North-South gradient in mortality observed in France was found to be much more pronounced for case fatality than for incidence. The proportion of milder acute myocardial infarction is currently increasing and this element should be taken into account when analysing CHD rates.     

Outcomes and health status of socially disadvantaged women during pregnancy

We sought to examine the health status of disadvantaged pregnant women more broadly and to consider if poor maternal health predisposes a woman to an adverse birth outcome. We surveyed 250 women recruited from six health centers in the greater Boston area during their third trimester. The main predictor variables were maternal physical functioning (PF), emotional health (EH), and overall health status in the month prior to pregnancy. The main outcome variables were the decline of maternal PF and EH during pregnancy and adverse birth outcomes. Mean PF scores fell from 91.9 prior to pregnancy to 63.7 during the third trimester (mean scores transformed 0 to 100, where a higher score represents better health). EH remained unchanged during pregnancy. After adjustment, women with a preexisting medical condition reported a lower PF score prior to pregnancy (87.8 versus 94.5, p < 0.05). Poor PF prior to pregnancy or during the third trimester was associated with an increased risk of preterm labor (odds ratio 2.02, 95% confidence interval 1.03-3.97). This study is the first to employ general health status measures to examine changes in health during pregnancy. Our findings support the use of preconception care to improve the health status of disadvantaged women with pre-existing conditions. This study suggests that poor maternal health may predispose a woman to an increased risk of preterm labor.     

Evaluation of a new fletcher applicator using cesium-137

The improved Fletcher Applicator¹ is a recent modification of the afterloading Fletcher system. Its aluminum construction reduces the weight by 50 % and is more comfortable for the patient. Removable caps contain medially placed tungsten screens that shield tissues anteriorly and posteriorly. When the caps are removed, the colpostats can be used as Delclos mini-ovoids. A method for evaluating the dosimetry of brachytherapy applicators in a water phantom was devised so this applicator could be studied and compared with other gynecologic applicators. The results show that the transmission ratios—the fraction of radiation transmitted through the tungsten shields—differ from those of the preloaded Fletcher colpostat, but are similar to the transmission ratios of the Fletcher-Suit applicator. There is a 10 % to 25 % reduction in the radiation dose to the region of the bladder trigone and anterior rectum with the shield containing cap in place. This percent reduction in dose is in agreement with other Fletcher applicators. Misalignment of the source basket within the colpostat, and motion of the source in the carrier cause variations in the dose rate at specific distances from the colpostat.     

Progressive resistance neck exercises using a compressible ball coupled with an air pressure gauge

Strength training of neck muscles, a potentially important approach to injury prevention and rehabilitation, has been limited by the lack of a convenient means of instituting progressive resistance exercise (PRE) programs. By positioning a compressible ball coupled with an air pressure gauge between the head and a wall, eight men, ranging in age from 21 to 46 years, initially measured the maximum voluntary pressure (MVP) generated within the ball (a measure of neck muscle force), while maximally flexing, extending, and laterally flexing their head into the ball. In accordance with PRE principles, they then performed three sets of 10 repetitions of each motion while maintaining ball pressure at 60-80% of the measured MVP. This training program, consisting of three to five sessions per week for 4-7 weeks: 1) increased the MVPs for flexion [to 156 +/- 9% (SE) pretraining, p < 0.05], extension [to 162 +/- 11% (SE) pretraining, p < 0.05], and lateral flexion [to 173 +/- 12% (SE) pretraining, p < 0.05]; and 2) decreased the disparity between the MVPs for left and right lateral flexion, indicating that the weaker side showed greater improvement than the stronger side (p < 0.05). These findings demonstrate that progressive resistance neck exercises, facilitated by a compressible ball coupled with an air pressure gauge, can markedly increase neck muscle strength and decrease lateral force imbalance. J Orthop Sports Phys Ther 1992;16(6):275-280.     

Calcitonin Gene-related Peptide Stimulates the Induction of c-fos Gene Expression in Rat Astrocyte Cultures

The action of calcitonin gene-related pepide (CGRP) was studied on c-fos gene expression in rat astrocyte cultures. A strong and transient increase in c-fos mRNA was observed in cultured astrocytes after treatment with CGRP. Quantitative Northern blot analysis revealed an increase of c-fos mRNA within 15 min, a peak after 30 min with a 10 - 15 fold increase over unstimulated cells and a subsequent decline. Induction of the c-fos gene by CGRP was concentration-dependent, half maximal stimulation of c-fos mRNA being obtained with 100 nM CGRP. The CGRP effect appeared to be mediated by a CGRP receptor and calcitonin was found to mimic only weakly the action of CGRP on cultured astrocytes. Calcitonin transiently induced c-fos gene expression with a similar time course to CGRP, but its effect was much less pronounced. Agents affecting the intracellular cyclic AMP level, forskolin and Ro 20-1724, stimulated c-fos mRNA in a strong and transient fashion with a temporal sequence similar to the response to CGRP. Further, the phosphodiesterase inhibitor Ro 20-1724 potentiated the action of CGRP on c-fos mRNA induction, suggesting a role for cyclic AMP in the action of CGRP. The present results indicate that CGRP may play a physiological role as a regulator of astrocyte gene expression.     

55. Einfluß der Blutmikrofiltration bei Massivtransfusionen

Zusammenfassung Die Mikrofiltration soll Aggregate und Zellzerfallsprodukte aus dem Transfusionsblut entfernen, ohne den Blutdurchfluß zu beeinflussen, einen Anstieg des freien Hämoglobins zu verursachen und ohne die Blutgerinnung zu aktivieren. Im Hinblick auf diese Anforderungen haben wir das Standard-Transfusion-Set, den Pall- und MF-10-Mikrofilter untersucht. Mit gesteigerter Blutmenge fanden wir leichte Anstiege des freien Hämoglobins und der Durchflußzeiten, deren Ausmaße mit der Porengröße der verwendeten Filter korrelieren. Bei Massivtransfusionen müssen deshalb 101i Porenfilter öfter gewechselt werden als 40 Porenfilter. Die Mikrofiltration von Blut aktiviert die Gerinnung nicht, sondern entfernt gerinnungsfördernde Substanzen.