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Biomedical subjects

W C Clark

Publications and source records attributed to W C Clark.

88 records · Page 5Linked to original sources
PubMed1969

Venom neutralization by rattlesnake serum albumin.

The blood serum of the eastern diamond back rattlesnake (Crotalus adamanteus) neutralizes lethal doses of C. adamanteus venom in mice. The protective capacity of the serum is associated with the serum albumin, rather than the immunoglobulin fraction of the blood. Neither the serum nor its albumin fraction form precipitin bands on immunophoresis against venom.

Animals↗
PubMedDate not supplied

Effects of moderate and high doses of marihuana on thermal pain: a sensory decision theory analysis.

Sixteen habitual marihuana users, selected for their good mental and physical health, were hospitalized for three months in the New York State Psychiatric Institute. During the first month, the subjects were drug free; during the second month, they smoked marihuana cigarettes provided by NIDA (2% THC, 20 mg per cigarette) at the rate of 3 to 12 a day. A modified Hardy-Wolff dolorimeter was used to present 20 thermal stimuli of 30-second duration in a random manner at nine different intensities. Subjects responded from a 14-category scale, and data were analyzed according to sensory decision theory analysis. During the third month, the subjects were again drug free. At the noxious thermal intensities, there was a decrease in the pain report criterion during the first two weeks of smoking. The pain enhancement effect was followed by return to the presmoking pain level during weeks 3 and 4 and in the postsmoking period, indicating that tolerance had developed. There was also an increase in pain discriminability during the four weeks of smoking which extended for one week after smoking. Tolerance developed to the pain report criterion but not to the thermal discriminability. This study suggests that marihuana may have hyperalgesic activity and probably enhances the perception of pain, in moderate smokers. In contrast, heavy smoking had little effect on discriminability and caused an increase in the pain report criterion.

Adolescent↗
PubMedDate not supplied

CO2 laser stapedotomy: is it practical?

The argon laser has been described as an instrument capable of performing stapedotomy for otosclerosis. Because of the possibility of cost ineffectiveness and damage to the saccule using the argon laser, this study was undertaken to ascertain the possibility of using the CO2 laser for stapedotomy. the operation was done on seven cats, and the resulting histopathologic findings were studied. Stapedotomy was also performed with the CO2 laser on human cadaver temporal bones to measure temperature changes in the vestibule and to develop guidelines for the laser's use in humans. The authors' results indicated that the CO2 laser can be used effectively and safely in cats and should be considered for human use.

Animals↗
PubMedDate not supplied

Thermal sensory decision theory indices and pain threshold in chronic pain patients and healthy volunteers.

Fifty-five low back pain patients and 47 healthy volunteers judged the intensity of calibrated thermal stimuli. The method of constant stimuli yielded a pain threshold, and sensory decision theory (SDT) methods provided two independent indices of perceptual performance: discriminability, P(A), the ability to differentiate among various stimulus intensities; and report criterion, B, the tendency to use a particular response. Compared to healthy volunteers, chronic pain patients were far poorer discriminators [lower P(A)]. In addition, the chronic pain patients were more stoical (higher B) and had higher thresholds for reporting both very faint pain and pain. The poor discriminability in patients could be due to attenuation of afferent neural input. The higher criterion suggests that the thermal stimuli were perceived as being innocuous relative to their clinical pain. Comparison of SDT indices with the threshold measures revealed that the pain threshold was highly correlated to the subject's criterion for reporting pain, B, and unrelated to discriminability, P(A).

Adaptation, Physiological↗