Alteration in myelin-associated proteins following spinal cord irradiation in guinea pigs.

The aim of this study was to investigate the pathological and cellular basis for radiation-induced myelopathy in guinea pigs by monitoring biochemical alterations in levels of myelin basic protein and 2',3'-cyclic nucleotide phosphohydrolase. Guinea pigs were irradiated to the lumbar region with various doses of neutrons or cobalt gamma irradiation. The ED50s for paralysis were 17.2 Gy and 67.5 Gy for neutron and cobalt irradiation, respectively, and was histologically associated with demyelination. In spinal cords taken from animals at the onset of paralysis myelin basic protein levels were decreased in direct relationship to the radiation dose. The lowest doses to cause paralysis led to a 25% decrease in MBP levels. In a separate experiment, alterations in MBP were measured in the spinal cords over the time period leading up to paralysis. Surprisingly, decreases in MBP were found immediately after the end of the 4 week irradiation period. These early changes in MBP were not markedly dose dependent and occurred with nonparalyzing doses. Dose-dependent decreases were found only just before the onset of paralysis. CNPase activity measured in the same specimens showed changes that were essentially similar to those for MBP. In the CSF, MBP levels were essentially constant until onset of paralysis. This study showed that demyelination, as assessed by the levels of the myelin-associated proteins MBP and CNPase, can occur soon after spinal cord irradiation but that profound dose-dependent changes are seen only immediately preceding the onset of paralysis. Although increases in MBP in the CSF were associated with the onset of radiation-induced myelopathy, its assay is unlikely to predict this complication of irradiation.     

Smoking in patients with panic disorder.

We compared smoking prevalence in 217 patients with panic disorder with that in 217 age- and sex-matched control subjects who were obtained by telephone survey from the same neighborhoods. Data were obtained for current smoking habits and smoking status at either the onset of illness (patients) or 10 years previously (control subjects). Patients had been ill for 10.6 (SD = 10.0) years. Female patients with panic disorder had a significantly higher smoking prevalence at the onset of their illness than did control subjects 10 years previously (54% vs. 35%). The current smoking prevalence for female patients was also significantly higher than that of control subjects (40% vs. 25%). Male smoking rates did not differ between patients and control subjects. Caffeine use did not appear to explain these findings. These data suggest a link between smoking behavior and panic disorder in women.     

Lorazepam versus diazepam for the treatment of status epilepticus

A retrospective study was performed to compare intravenous lorazepam and intravenous diazepam in the treatment of status epilepticus. Forty-five episodes of status epilepticus in children between the ages of 2 weeks and 18 years were reviewed. Lorazepam and diazepam proved similar in efficacy of seizure control and incidence of adverse effects. The dose of lorazepam required to control status epilepticus ranged from 0.03 to 0.22 mg/kg with a mean of 0.11 mg/kg (S.D. = 0.05 mg/kg). Among children treated with lorazepam, only children younger than 2 years of age had respiratory depression which required intubation.     

Platelet and whole blood serotonin content in depressed inpatients: correlations with acute and life-time psychopathology.

Platelet or whole blood serotonin content did not differ significantly in patients with major depression compared to healthy controls, but within the patient group, platelet serotonin levels correlated negatively with severity of depression (r = -0.49, p = 0.007). Levels were 39% lower in patients who had made a suicide attempt compared to nonattempter patients (47.2 +/- 27.3 versus 77.6 +/- 41.7 ng/10(8) platelets, p = 0.04). Conversely, comorbid borderline personality disorder (85.3 +/- 41.5 ng/10(8) platelets) was associated with 31% greater platelet serotonin content than nonborderline patients (58.9 +/- 31.1 ng/10(8) platelets) and 27% greater than healthy controls (62.4 +/- 19.8 ng/10(8) platelets). A pronounced seasonal variation in whole blood and platelet serotonin content was found in both patients and controls, largely due to lower levels in summer. Excluding cases tested in the summer abolished the statistically significant differences in patients with and without comorbid borderline personality disorder (BPD). Nevertheless, BPD attempters had lower serotonin levels than BPD nonattempters but higher serotonin levels than non-BPD attempters. Current hostility and a life-time history of aggression were positively correlated with platelet serotonin content (r = 0.44, p = 0.04 and r = 0.41, p = 0.06). This study provides evidence for an association between lower platelet serotonin content and depression and suicidal behavior, and association of higher platelet serotonin content and comorbid borderline personality disorder and behavior traits such as aggressivity.