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Biomedical subjects

J W Crayton

Publications and source records attributed to J W Crayton.

At least 37 records · Page 2Linked to original sources

Adverse reactions to foods: relevance to psychiatric disorders.

There is some evidence in the literature that adverse reactions to foods can contribute to behavioral dysfunction. In view of what is known about food and behavior, this suggestion is entirely plausible. However, clear demonstrations of adverse behavioral reactions to foods have not been reported. The major methodologic problems are those of defining suitable baseline conditions and dealing with large ranges in dose, time course, and severity of reactions among putatively food-sensitive individuals. These problems, although large, are surmountable. Another problem for studies in this area is nomenclature. The imprecision with which terms are used undoubtedly will diminish as the various mechanisms by which food can affect individuals are delineated. Until these issues are clarified, we are confronted with a group of patients who are convinced that their symptoms are somehow related to the food that they eat. Some basic guidelines may help in the initial screening of these patients. If a history of behavioral dysfunction related to food intolerance occurs in the context of other signs of allergy or hypersensitivity, it seems prudent to evaluate and treat the allergic or hypersensitivity condition and note the effect of that treatment on behavior. If the food complaints occur in the context of marked suggestibility and large numbers of unexplained complaints are registered without any evidence of allergy or hypersensitivity, a diagnosis of somatization disorder should be entertained. If food complaints occur in a patient who does not meet the criteria for somatization disorder, a working diagnosis of undiagnosed medical condition should be entertained.(ABSTRACT TRUNCATED AT 250 WORDS)

Anxiety Disorders↗

Blood tryptophan metabolism in chronic schizophrenics.

Concomitant measures of blood indole metabolism were conducted in 33 chronic schizophrenics who showed significantly elevated mean platelet serotonin (5-HT) values and lower platelet monoamine oxidase (MAO) and plasma amine oxidase activities than normals. When subdivided according to Research Diagnostic Criteria diagnosis, the 20 chronic undifferentiated (CU) schizophrenics showed these same deviations from normal; the 13 chronic paranoid (CP) schizophrenics also had significantly higher mean 5-HT values but significantly lower plasma concentrations of total and bound tryptophan. In CP schizophrenics, platelet MAO activity, but not plasma amine oxidase activity, was significantly lower than in CU schizophrenics and controls. Hyperserotonemia occurred in 11 of the chronic patients (33%); nine were CU schizophrenics. In the latter, total tryptophan concentration was significantly lowered. Hyperserotonemia was not associated with reduced liver tryptophan pyrrolase activity or platelet MAO or plasma amine oxidase activities; rather, it may be a consequence of enhanced tissue tryptophan uptake and utilization.

Adult↗

Myasthenia induced by monoclonal anti-acetylcholine receptor antibodies: clinical and electrophysiological aspects.

To investigate individual components of the humoral immune response directed against the acetylcholine receptor in experimental myasthenia, we injected monoclonal antireceptor antibody into normal rats. These antibodies were produced by cloned hybridoma lines formed by fusion of immune spleen cells with the myeloma cell line P3-X63-Ag8. Antibodies from two of seven clones induced acute experimental myasthenia, manifested by clinical weakness, decremental electromyographic response to repetitive nerve stimulation, and diminished mean amplitudes of miniature end-plate potentials (mepps): 0.55 +/- 0.02 mv (SEM) versus 0.71 mv for controls (p less than 0.001). In clinically affected animals, mepp amplitudes from the diaphragm correlated with decremental responses in the gastronemius muscle (r = -0.91, p less than 0.01). The results suggest that binding of a single antibody species to a single determinant on the acetylcholine receptor molecule is sufficient to induce acute experimental myasthenia gravis.

Animals↗

An oscillatory component of the H-reflex.

H-reflex recovery curves studied in 57 normal volunteers could be divided into three groups: one with sinusoidal properties having one or more periods, one having primarily linear or exponential properties, and a third, indeterminate group.

Adolescent↗

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↗

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↗

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↗

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↗

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↗

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↗