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Biomedical subjects

J W Crayton

Publications and source records attributed to J W Crayton.

16 recordsLinked to original sources
PubMed1992

Regulation of murine T-lymphocyte function by spleen cell-derived and exogenous serotonin.

The modulatory effects of serotonin on T-cell activity were investigated. T-cell blastogenesis of normal spleen cells was slightly stimulated by the addition of low doses (1 and 10 ng/ml) of the inducer of serotonin release, fenfluramine. In contrast to the stimulatory effects of low doses of fenfluramine, high doses of fenfluramine (1 and 10 ug/ml) or of exogenously added serotonin (> or = 0.1 ug/ml) inhibited T-cell activation. Both the stimulation by low dose fenfluramine and the inhibition by high dose fenfluramine were accentuated by pretreating mice with tryptophan to heighten intracellular stores of serotonin and then inducing serotonin release. Pretreatment of mice with the serotonin inhibitor p-chlorophenylalanine (PCPA) abolished the fenfluramine inhibition of T-cell activation indicating that the fenfluramine inhibitory effect was mediated via endogenous spleen cell-derived serotonin. However, the PCPA treatment diminished T-cell activation. These results suggest that endogenous serotonin causes a biphasic dose-response effect on T-cell activity with serotonin being required for optimal T-cell function, low doses being immune stimulatory and higher doses being suppressive.

Adjuvants, Immunologic↗
PubMed1979

Improvement in tardive dyskinesia after muscimol therapy.

Muscimol, thought to be a agonist of gamma-aminobutyric acid (GABA), was administered to eight neuroleptic-free subjects with tardive dyskinesia. At oral dose levels from 5 to 9 mg, involuntary movements were consistently attenuated, usually in the absence of sedation. These results support the view that pharmacologic attempts to stimulate GABA-mediated synaptic transmission may afford symptomatic relief to patients with tardive dyskinesia.

Adult↗
PubMed1979

Relationship of butaperazine blood levels to plasma prolactin in chronic schizophrenic patients.

The relationship of plasma prolactin to plasma or red blood cell butaperazine levels was investigated in chronic schizophrenic patients treated with clinical doses of butaperazine, both after a single acute dose of the drug and during regular, twice daily butaperazine administration. Although there was a significant curvilinear relationship between peak plasma butaperazine levels after an acute single oral dose of butaperazine and the maximum prolactin response that we measured, steady-state levels of plasma or red cell butaperazine and plasma prolactin were not related. We conclude that plasma prolactin cannot be used as a substitute for or even as a rough indicator of butaperazine blood levels in chronic schizophrenic patients being treated with clinical doses of butaperazine.

Adult↗
PubMed1979

Degeneration and regeneration of motor neurons in psychotic patients.

The pattern of distribution of intramuscular nerve twigs was studied in muscle biopsies of peroneus brevis muscle from 62 schizophrenic and affective psychotic patients, and 8 normal control volunteers. Using methylene blue staining, the incidence of abnormally increased collateral branching was significantly greater in the patient population compared with normal controls. Paranoid psychotic patients had significantly higher values for branching than did non-paranoid schizophrenics. Abnormal branching was also correlated with excessive percentages of small angular muscle fibers. There was a significant relationship between increased branching and a positive family history of psychosis. The findings are suggestive of a process of neuronal degeneration followed by compensatory regeneration in some psychotic patients.

Adolescent↗
PubMed1977

The motor unit in psychotic patients: a single fibre EMG study.

Single fibre EMG recording from extensor digitorum communis muscle is described in patients with psychotic illness. The fibre density, or average number of single muscle fibre action potentials belonging to the same motor unit within the uptake area of the electrode, was higher in the patient group than in normal controls. Increased jitter was occasionally seen. Motor and sensory nerve conduction velocity values were within the normal range. The results indicate that psychosis is associated with denervation and reinnervation by collateral sprouting.

Adult↗
PubMed1977

Electrophysiological (H-reflex) studies of patients with tardive dyskinesia.

The authors studied the H-reflex recovery curves of 31 schizophrenic patients with tardive dyskinesia in response to acute administrations of apomorphine, amphetamine, or physostigmine and compared them with curves of chronic schizophrenic patients without tardive dyskinesia and normal volunteers. Their most unexpected finding was the absence of an H-reflex in 9 of the 31 patients with tardive dyskinesia. They also found a relationship between severity of tardive dyskinesia and the value of the facilitatory peak Hchi: patients with more severe tardive dyskinesia symptoms had significantly higher values for Hchi.

Amphetamine↗
PubMed1977

Motoneuron excitability in psychiatric patients.

The excitability at the alpha-motoneuron pool was studied by measuring the spinal monosynaptic reflex responses of soleus muscle to paired stimuli in psychiatric patients and controls. Patients showed significant alterations in the recovery of excitability when compared with normal volunteers. Specifically, the value for the peak of "secondary facilitation" was reduced in 5 of 8 chronic schizophrenic patients, while the following trough in the recovery cycle was reduced in 9 of 18 acutely schizophrenic patients. Drug effects were studied in 10 patients. Phenothiazine antipsychotic medication tended to enhance recovery of excitability. Patients of all types showed alterations of excitability. The altered excitability may relfect one aspect of a widespread abnormality of CNS function or may be a specific response to a supraspinal defect in neurophysiological activity in psychotic patients.

Affective Disorders, Psychotic↗
PubMed1976

Serum creatine phosphokinase activity in psychiatrically hospitalized children.

Serum creatine phosphokinase (CPK) activity was determined in a series of 101 sequential admissions to the Pritzker Children's Hospital, an inpatient psychiatric facility. Black children had significantly higher serum CPK levels than whites, and males had significantly higher levels than females, as is the case with adults. There was a higher incidence of CPK elevations in children with organic brain pathology than in children with personality disorders or schizoprenia. Children with chronic symptoms of a psychotic nature did not have increased serum CPK activity, which is similar to the findings in adults. There were no children in the sample with acute psychotic symptoms, so it was not possible to determine whether acute psychosis in children is accompanied by increased serum CPK activity, as it frequently is in psychotics over the age of 17.

Adolescent↗
PubMedDate not supplied

Penicillamine-induced myasthenic responses in the guinea pig.

To study the basis for the myasthenic illness that develops in some patients receiving D-penicillamine (D-P), we measured neuromuscular transmission in D-P-treated guinea pigs. Treated animals manifested edrophonium chloride-repairable decremental responses to 30-Hz nerve stimulation (8.5% +/- 1.5%--mean +/- SEM; N = 16) compared with the response in saline-treated control animals (-0.3% +/- 0.85%, N = 10, p less than 0.005). Posttetanic phenomena were studied in 5 treated animals; 3 revealed posttetanic exhaustion. Miniature endplate potential (MEPP) amplitudes were significantly reduced in 11 treated animals (0.612 +/- 0.016 mV) compared with 6 controls (0.713 +/- 0.024 mV, p less than 0.01). The MEPP frequency appeared reduced in treated animals. Both MEPP amplitude and MEEP frequency correlated with the decrement.

Animals↗