Influence of renal clearance on peripheral homovanillic acid measurements in healthy subjects and schizophrenic patients.

In order to investigate the effect of renal clearance on plasma homovanillic acid (HVA) concentrations, we examined plasma concentration and urinary excretion of HVA and creatinine per 4 h over 24 h in eight male schizophrenic patients and eight healthy male subjects. Renal clearances of HVA and of creatinine were determined per 4 h period. No significant differences were found between groups in the total 24 h excretion of either HVA or creatinine. Although differences between groups in plasma HVA concentrations and urinary HVA excretion per 4 h did not reach statistical significance, the renal clearance of HVA was significantly lower in the patient group than in the control group. There was no difference between groups in creatinine clearance. Diurnal changes were seen in the renal clearance of HVA and creatinine in both groups. Renal HVA clearance decreased from 23.00-07.00 h, with a coincident decrease in urinary HVA excretion and an increase in plasma HVA concentration. We provide evidence that renal clearance is an important determinant of plasma HVA concentration, and should be considered when interpreting plasma HVA data.

Sleep, Epstein-Barr virus infection, musculoskeletal pain, and depressive symptoms in chronic fatigue syndrome.

Sleep physiology, viral serology and symptoms of 14 patients with chronic fatigue syndrome (CFS) were compared with 12 healthy controls. All patients described unrefreshing sleep and showed a prominent alpha electroencephalographic nonrapid eye movement (7.5-11.0 Hz) sleep anomaly (p less than or equal to 0.001), but had no physiologic daytime sleepiness. There were no group differences in Epstein-Barr virus (EBV) antibody titers. The patient group had more fibrositis tender points (p less than 0.0001), described more somatic complaints (p less than 0.0001), and more depressive symptoms (p less than 0.0001). Patients with CFS do not show evidence for a specific chronic EBV infection, but show altered sleep physiology, numerous tender points, diffuse pain, and depressive symptoms. These features are similar to those found in fibromyalgia syndrome.

Developmental and neurologic correlates of treatment response in schizophrenia.

Reliable predictors of outcome in schizophrenia remain elusive, and assessment of unidimensional variables is unlikely to provide new information. We examined developmental, neurologic and psychosocial variables together to assess their correlation with several separate aspects of outcome in male schizophrenic patients (N = 31) treated with neuroleptics for a minimum of six months. Outcome measures evaluating social performance were significantly inter-correlated, but these measures did not correlate significantly with "positive" symptom measures. Persistent positive symptoms were predicted by post-natal neurologic impairment. Persistent negative symptoms and social dysfunction were predicted by psychosocial dysfunction during the developmental years. Poor early treatment response significantly correlated with persistent positive symptoms and psychosocial dysfunction. Impairment on neurobehavioral testing correlated significantly with post-natal neurologic impairment and with persistent positive symptoms.