Jonathan H. Pincus

Unilateral Destruction of Dopamine Pathways Increases Ipsilateral Striatal Serotonin Turnover in Rats

In order to evaluate the influence of dopaminergic transmission on regional brain utilization of serotonin (5HT), the effects of the destruction of the ascending dopamine (DA) pathways on regional brain 5HT metabolism in the rat were examined. Complete unilateral lesions of the nigrostriatal DA pathways (> 90% DA loss) were made by infusing the neurotoxin 6-hydroxy-dopamine into either the left medial forebrain bundle (MFB) or the left substantia nigra (SN). At 6 weeks after the lesions, levels of 5HT and its major metabolite, 5-hydroxyindoleacetic acid (5HIAA), were determined bilaterally in the striatum, frontal cortex, and hypothalamus. In the striatum of the lesioned hemisphere, the 5HT level decreased by more than 50%, while the ratio of 5HIAA:5HT (an index of 5HT turnover) increased by more than 90%. In the same rats, cortical and hypothalamic 5HT, 5HIAA, and 5HT turnover were not changed as a result of the MFB or SN lesions. These results suggest that the loss of DA innervation in the striatum triggers an increase in 5HT turnover and a net depletion of 5HT in the striatum. To verify that the loss of DA was responsible for the observed striatal 5HT changes, we examined the effect of intracerebral implantation of DA-containing pellets into one group of MFB-lesioned rats. The lesioned rats with placebo pellets did not differ from lesioned rats without pellets, whereas the implantation of DA pellets reversed the lesion-induced changes in the 5HT levels and 5HIAA:5HT ratios.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspartame use in Parkinson's disease

The artificial sweetener aspartame (Nutra Sweet) is hydrolyzed in the gut as phenylalanine (PA), a large neutral amino acid (LNAA). LNAAs compete with levodopa for uptake into the brain. To determine the effect of aspartame on levodopa-treated Parkinsons disease (PD) patients, we studied 18 PD patients with protein-sensitive motor fluctuations by administering in a double-blind and single-crossover design, on alternate days, aspartame (600 or 1,200 mg) and placebo. Every hour, we performed a motor examination and drew blood to estimate plasma LNAA, PA, and levodopa levels. Six-hundred mg of aspartame had no effect on plasma PA or motor status. Although 1,200 mg of aspartame significantly increased plasma PA, motor performance did not deteriorate. Aspartame consumption in amounts well in excess of what would be consumed by heavy users of aspartame-sweetened products has no adverse effect on PD patients.

Screening for Mild Traumatic Brain Injury in the Presence of Psychiatric Comorbidities

OBJECTIVE To determine whether or not a battery of neurobehavioral tests, the Brief Objective Neurobehavioral Detector (BOND), could detect mild traumatic brain injury (mTBI) among a group of psychiatric inpatients with numerous substance-related and medical comorbidities. The 16-item BOND is comprised of neurologic examination tasks and has been shown to correlate with radiologic and cognitive findings in previous studies. DESIGN Masked comparison. SETTING Inpatient psychiatric unit at the Veterans Affairs Medical Center in Washington, DC. PARTICIPANTS Patients (N=51) sequentially admitted for suicidal ideation in the context of various psychiatric disorders. INTERVENTIONS No intervention. MAIN OUTCOME MEASURE BOND total and subtest scores. RESULTS Forty-three patients were eligible and analyzed. Twenty-seven had sustained an mTBI in the distant past, and 16 had never sustained a traumatic brain injury (TBI) (non-TBI group). On average, the mTBI group demonstrated a significantly greater number of abnormal subtests on the BOND (mean, 7.22) than did the non-TBI group (mean, 4.50; P=.003). Although the BOND significantly correlated with the presence of mTBI, it did not correlate with any of the psychiatric, substance-related, or medical comorbidities. Multiple regressions indicated that the BOND total score was not explained by age, posttraumatic stress disorder diagnosis, or any combination of the psychiatric, substance-related, or medical comorbidities. High rates of sensitivity (70%) and specificity (69%) were found. CONCLUSIONS The results of this pilot study suggest that the inexpensive, brief, and objective BOND instrument may be a useful screening tool for the detection of subtle neurologic brain abnormalities after mTBI, even in the presence of substantial comorbidities.

Reply from the Authors Neurology and murderers

Reply from the Authors: We agree with Dr. Di Rocco that poverty, lack of education, and lack of a supportive environment are potential factors for the formation of violent behavior and are often present in violent subjects, but they do not cause violence when they occur as isolated phenomena. Interestingly, about one-third of our criminal offenders were not from the lowest socioeconomic groups, but rather, were in Hollingshead and Redlich Group III. Clearly, most individuals who are poor …

Evaluation of the Violent Adolescent

There is considerable disagreement regarding the prevalence and severity of neuropsychiatric impairment in the delinquent and criminal populations. Similar disagreement exists in the literature concerning the medical histories of delinquents. There is, however, a growing body of evidence that certain forms of delinquency are associated with disorders of the nervous system.