Hyperbaric oxygen as prophylaxis or treatment for radiation myelitis.

This animal study was designed to investigate HBO as a treatment or prophylaxis for radiation myelitis. All animals received identical spinal cord radiation doses of 69 Gy in 10 daily fractions. Group I received no HBO; group II began HBO at the onset of signs of myelitis; group III received HBO with prophylactic intent beginning 6 wk after irradiation; and group IV received both modalities on the same day, but radiation always preceded HBO by at least 4 h. HBO consisted of 90 min oxygen at 2.4 atm abs for 20 daily treatments. Animals were objectively assessed for the loss of certain neurologic reflexes indicative of four levels of myelitis. Although all animals progressed to severe myelitis, group III animals had group-averaged levels of myelitis consistently less than control. The differences were statistically significant for several weeks. Group IV animals progressed to severe myelitis much more rapidly than any other group. Additional study is justified by this trial. Key questions to be answered include the optimal timing of HBO to produce a beneficial rather than detrimental effect.

Control of protein synthesis by amino acid supply. The effect of asparagine deprivation on the translation of messenger RNA in reticulocyte lysates.

The enzyme asparaginase, which hydrolyses asparagine to aspartic acid, inhibited cell-free protein synthesis by reticulocyte lysates. The inhibition was rapid and complete when sufficient enzyme was added but could be prevented or reversed by the addition of asparagine. The initial effect of asparaginase appears to be a block in polypeptide chain elongation due to asparagine deprivation, but there are some indications that prolonged incubation under these conditions may give rise to a secondary decrease in initiation of protein synthesis.

Effects of demand for performance, self-monitoring of arousal, and increased sympathetic nervous system activity on male erectile response.

Clinical programs for the treatment of impotence generally have been successful but without experimental verification of their individual components or factors associated with the development of impotence. Twenty-four normal males participated in an investigation comparing factors believed to inhibit or facilitate penile tumescence. The effects of demand for performance, self-monitoring of erection, and increased SNS activity, were evaluated. Subjects were exposed to sexual stimuli under these conditions and measurements of penile responses were taken. Results indicated that there were no differential effects on penile responses between demand and no-demand or between self-monitoring and no self-monitoring. Increased SNS activity appeared to facilitate loss of erection, but only after, and not during, the sexual stimulus. The clinical and theoretical implications of these findings are discussed, and suggestions are made for future research.

Psychological functioning of bipolar manic-depressives in remission.

Several dimensions of psychological functioning of bipolar manic-depressives in remission were investigated. The following hypotheses were examined: (1) During remission, these individuals exhibit psychological maladjustment or a lack of positive mental health. (2) Bipolar manic-depressives are characterized by strong external orientations. The Personal Orientation Inventory, Marlowe-Crowne Social Desirability Scale, Levenson's Internal and Powerful Others Locus of Control Scales, and the Embedded Figures Test were administered to matched groups of 35 bipolar manic-depressives and 35 normal comparison subjects. Discriminant analysis disclosed no significant differences between the two groups on measures of positive mental health and on measures of external orientation. The relationship between these results and the etiology and treatment of manic-depressive disorder is briefly discussed, as well as the contradiction these findings pose to current views of this disorder pervasive among professional and lay populations.