The influence on spinal cord evoked potentials of chymopapain applied to the rat lumbar spine canal

Electrically evoked compound action potentials were used to quantify the neurophysiologic abnormalities caused by application of chymopapain into the lumbar spinal canal in rats. A branch of the sciatic nerve was stimulated with voltage impulses of constant amplitude (40 V) and duration (0.1 msec) at the right external malleolus. The responses were recorded at the dorsal root entry zone L1. The authors used different doses of chymopapain (low dose = 100 IU, middle dose = 250 IU, and high dose = 500 IU). The control rats were subjected to exactly the same stimulus and recording procedures, but the test solution was a corresponding volume of isotonic saline. The prolongation of the latency of the electrically evoked potential due to chymopapain is very clear at the doses of 250 IU and 500 IU, being about 10 to 15% relative to the mean latency before application of the drug. This study indicates that locally applied chymopapain has a dose-dependent effect on nerve conduction properties.     

Sociodemographic risk indicators for depressive symptoms among persons with oral cancer or oral epithelial dysplasia.

PURPOSE: We report findings from a study that measured associations between sociodemographic risk indicators and depressive symptoms among individuals diagnosed with either oral cancer or a premalignant lesion. MATERIALS AND METHODS: Incident cases of oral cancer and oral epithelial dysplasia (OED) were identified by reviewing pathology reports generated by 3 oral pathology laboratories serving primarily community-based oral and maxillofacial surgeons. Subjects were interviewed by telephone to collect information on sociodemographic characteristics, depressive symptoms using the Center for Epidemiologic Studies-Depression (CES-D) Scale, and social support using the Berkman Social Network Inventory. RESULTS: The analysis included 167 oral cancer and 234 OED cases. Nineteen percent of the subjects had a CES-D score indicative of clinical depression (CES-D > or =16). Forward and backward stepwise logistic regression identified diagnosis (cancer/OED), age, social support, employment status, and gender as sociodemographic indicators of CES-D scores of 16+. In the final model, which also controlled for smoking and drinking, the odds of having elevated CES-D scores (16+) were 79% higher among oral cancer relative to OED cases. The odds of high CES-D scores were significantly reduced in persons over the age of 50 compared with those aged 50 years and younger as well as in persons with higher, relative to low, levels of social support and in persons employed outside the home compared with those who were not. Although not statistically significant, men were more likely to have CES-D scores indicative of clinical depression. CONCLUSIONS: Knowledge of sociodemographic characteristics may assist the clinician in identifying those individuals with an elevated risk of concomitant depressive symptoms.     

Transport of an antifungal trypsin inhibitor isolated from corn across the blood-brain barrier

We determined whether an antifungal 14-kDa protein trypsin inhibitor isolated from corn is able to cross the blood-brain barrier. We found that it completely crossed the blood-brain barrier by means of a saturable mechanism at a rate of 0.153 microl/g. min, with about 0.082% of the intravenously injected dose being taken up per gram of brain.     

Fungicidal activity of cecropin A.

Cecropin A (CA) fungicidal properties were explored. Nongerminated and germinated Aspergillus spp. and Fusarium spp. conidia were treated with CA. CA achieved complete lethality at < or = 25 microM (99 micrograms/ml) for germinating, but not nongerminating, conidia of Aspergillus spp. CA achieved total lethality for nongerminated and germinating conidia of Fusarium spp at 1.5 microM (6 micrograms/ml). MIC and minimal lethal concentration assays in buffered RPMI medium gave similar results.     

Acoustic field of a ballistic shock wave therapy device

Shock wave therapy (SWT) refers to the use of focused shock waves for treatment of musculoskeletal indications including plantar fascitis and dystrophic mineralization of tendons and joint capsules. Measurements were made of a SWT device that uses a ballistic source. The ballistic source consists of a handpiece within which compressed air (1-4 bar) is used to fire a projectile that strikes a metal applicator placed on the skin. The projectile generates stress waves in the applicator that transmit as pressure waves into tissue. The acoustic fields from two applicators were measured: one applicator was 15 mm in diameter and the surface slightly convex and the second was 12 mm in diameter the surface was concave. Measurements were made in a water tank and both applicators generated a similar pressure pulse consisting of a rectangular positive phase (4 micros duration and up to 8 MPa peak pressure) followed by a predominantly negative tail (duration of 20 micros and peak negative pressure of -6 MPa), with many oscillations. The rise times of the waveforms were around 1 micros and were shown to be too long for the pulses to be considered shock waves. Measurements of the field indicated that region of high pressure was restricted to the near-field (20-40 mm) of the source and was consistent with the Rayleigh distance. The measured acoustic field did not display focusing supported by calculations, which demonstrated that the radius of curvature of the concave surface was too large to effect a focusing gain. Other SWT devices use electrohydraulic, electromagnetic and piezoelectric sources that do result in focused shock waves. This difference in the acoustic fields means there is potentially a significant mechanistic difference between a ballistic source and other SWT devices.     

In vivo quantification of lead in bone with a portable x-ray fluorescence system--methodology and feasibility

This study was conducted to investigate the methodology and feasibility of developing a portable x-ray fluorescence (XRF) technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal settings of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (intraclass correlation coefficient, ICC = 0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC = 0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 μSv and should pose minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements.