Psychophysics of muscle tension in psychiatric inpatients

Twelve psychiatric inpatients and 16 control subjects each took part in a psychophysics experiment in which the method of production was used to study the perception of tension in the frontalis and forearm extensor muscles. Subjects tensed each muscle between 0% and 50% maximum effort, with 25% effort repeated every third trial, and used as a reference stimulus. Patients showed significantly lower correlations between frontalis EMG and percent effort than the control subjects, but no between-groups differences were found for forearm. Correlations were higher for differences between successive trials than for absolute values because of apparent baseline shifts in perception and/or production of muscle tension. The performance among the patients was not correlated with severity of psychiatric symptoms, antipsychotic medication, abnormal movements, or parkinsonian symptoms, although the n was small. Analysis of the regression of EMG on percent effort revealed approximately equal descriptive strength for three functions: a linear relationship, Stevens' power function, and Fechner's law. The implications of these findings for self-regulation therapies are discussed.

Bromocriptine for "negative" schizophrenia

The hypothesis that the pathophysiology of negative symptoms in schizophrenia may involve relative hypoactivity of central dopaminergic neurotransmission prompts the exploration of dopamine agonist strategies in the treatment of this condition. Although the use of dopamine agonists in otherwise unmedicated schizophrenic patients often leads to the exacerbation of psychosis, trials of dopamine agonists in combination with neuroleptic agents warrant investigation. We therefore report on open clinical experience involving six patients with chronic negative symptoms of schizophrenia, maintained on neuroleptic medication, who appeared to have favorable responses to the addition of moderate doses of bromocriptine (10 to 20 mg/d orally in divided doses). One particular factor that makes these trials potentially informative is that five of the six patients had failed to respond to standard treatments with anticholinergic antiparkinsonian medication before the bromocriptine trial, making it unlikely that the bromocriptine had its effect purely by counteracting neuroleptic-induced akinesia. A trial of bromocriptine under these circumstances has never been reported. A second unique feature of this report concerns the lengthy period of follow-up. Adjunctive bromocriptine was continued for a total of 27 patient-years in the six individuals, with maintenance of favorable course and minimal incidence of psychotic exacerbation.

A somatic gene rearrangement contributing to genetic diversity in maize

We have discovered a somatic genomic rearrangement that occurs at high frequency at a duplicated zein locus in certain cultures of the maize inbred line A188. The rearranged allele arises from the duplication by a two-step process involving a homologous recombination and a second event, which may be a deletion, inversion, or insertion; both steps always occur together. The frequency of rearrangement is lower in homozygous states of the parental allele than in heterozygotes. In both cases, the rearrangement is shown to be mitotic. The rearranged product can be transmitted through meiosis, providing another mechanism for genome evolution in higher eukaryotes.