Can accurate ultrasonographic measurement of the optic nerve sheath diameter (a non-invasive measure of intracranial pressure) be taught to novice operators in a single training session?

Novices can be quickly and easily taught to ultrasonographically measure optic nerve sheath diameter as a noninvasive surrogate for intracranial pressure. One intensive care unit senior medical officer, one junior intensive care unit registrar, one junior neurosurgery trainee and two registered nurses, all ultrasound novices, were given a four-hour workshop on how to measure the optic nerve sheath diameter with ultrasound. One week later they had the accuracy of their technique assessed by recording their measurements for both eyes of 12 healthy volunteers. Each eye was measured three times and the average and 'best' measurements were determined. The median, 5th and 95th centiles and standard deviation for intra-observer variation were calculated. Median, 5th and 95th centiles for inter-observer variation were obtained by comparing each of the novice operator's measurements with those of an experienced sonographer Median intra-observer difference was < or = 0.27 mm, standard deviation < or = 0.46 mm and 95th centiles < or = 1.19 mm for the five novice operators. Comparing the average of three measurements for each eye, median inter-observer difference for all operators was < or = 0.42 mm and 95th centile values < or = 1.15 mm. Using the single 'best' measurement for each eye, median inter-observer difference was < or = 0.3 mm and 95th centiles < or = 1.43 mm. Ultrasonographic optic nerve sheath diameter measurement can be taught to novice operators in a four-hour workshop with variation comparable to published results collated from 'experts'.

Comparative acute and combinative toxicity of aflatoxin B1 and fumonisin B1 in animals and human cells

Aflatoxin B(1) (AFB(1)) and fumonisin B(1) (FB(1)) are important food-borne mycotoxins. The co-contamination of food stuffs with these two mycotoxins is well known and has been possibly implicated in the development of human hepatocellular carcinoma in high risk regions around the world. In this study the acute and combinative toxicity of AFB(1) and FB(1) were tested in F-344 rats, mosquitofish (Gambusia affinis), immortalized human hepatoma cells (HepG2) and human bronchial epithelial cells (BEAS-2B). Preliminary experiments were conducted in order to assess the acute toxicity and obtain LD(50), LC(50) and IC(50) values for individual toxins in each model, respectively. This was followed by testing combinations of AFB(1) and FB(1) to obtain LD(50), LC(50) and IC(50) values for the combination in each model. All models demonstrated a significant dose response in relation to toxin treatment. The potency of the mixture was gauged through the determination of the interaction index metric. Results of this study demonstrate that these two toxins interacted to produce alterations in the toxic responses with a strong additive interaction noted in the cases of F344 rats and mosquitofish. It can be gathered that this combination may pose a significant threat to public health and further research needs to be completed addressing alterations in metabolism and detoxification that may influence the toxic manifestations in combination. These results will provide foundational knowledge for future studies on long-term combinative toxic and health effects of these mycotoxins.

Brain stem evoked potential findings in children with otitis media

Sixty-three children from 2 to 12 years of age were studied by means of brain stem evoked potentials (BEP) and otoscopic evaluation in a preliminary assessment of the sensitivity of BEP latency measures to middle ear abnormality. Wave I proved to be the most sensitive component; 81.25% of subjects with acute suppurative otitis media and 62.50% of subjects with secretory otitis media demonstrated latencies prolonged by more than 1 SD beyond the values observed in normal control subjects. Of the same subject groups, 86.21% and 93.31% demonstrated wave I latencies within normal limits upon retesting after the otitis had resolved. The BEP technique permitted identification of several subjects with abnormal audiometric findings despite normal otoscopy. There are implications for use of the BEP as a clinical adjunct to traditional methods of auditory assessment.