Search PubMed⌕ Search

Biomedical subjects

C F Terrence

Publications and source records attributed to C F Terrence.

At least 37 records · Page 2Linked to original sources

Do phenytoin and carbamazepine depress excitation and/or facilitate inhibition?

The effect of phenytoin and carbamazepine on the segmental and the periventricular inhibition was investigated in interneurons of the spinal trigeminal nucleus oralis of cats. The segmental inhibition was elicited by delivering a conditioning stimulus to the maxillary nerve 100 ms prior to the test stimulus to the maxillary nerve, and the periventricular inhibition was elicited by delivering a conditioning stimulus to the periventricular gray matter. Therapeutic serum levels of phenytoin and carbamazepine facilitated the segmental inhibition, but depressed the periventricular inhibition, while also depressing the response of trigeminal nucleus neurons to an unconditioned maxillary nerve stimulus. These results indicate that the depression of neural activity by phenytoin and carbamazepine is selective, leaving some inhibitory pathways relatively untouched and thus greatly enhancing their effectiveness. It is suggested that the anticonvulsant properties of phenytoin and carbamazepine are due to their ability to produce a relative facilitation of inhibitory feedback mechanisms.

Animals↗

Complications of baclofen withdrawal.

In three patients taking baclofen on a long-term basis, hallucinosis and/or seizures developed with abrupt reduction of dose or discontinuation of baclofen therapy. These cases emphasize the advisability of tapering the dose of baclofen gradually after long-term administration.

Adolescent↗

Neurogenic pulmonary edema in unexpected, unexplained death of epileptic patients.

Eight cases of unexpected, unexplained death in young ambulatory epileptics were examined postmortem with special attention to the heart and lungs. Lung weights uniformly exceeded the expected value, with gross evidence of hemorrhagic pulmonary edema. Microscopic examination revealed moderate to severe pulmonary edema with protein-rich fluid as well as alveolar hemorrhage. There was no evidence of recent or old myocardial disease. Although death due to a seizure is usually thought to be almost instantaneous, the neurogenic pulmonary edema exemplified by these cases takes time to develop and may be remediable. The high frequency of absent or non-therapeutic anticonvulsant levels at the time of death in these patients may play a role in a possible centrally mediated adrenergic cause of neurogenic pulmonary edema and ventricular arrhythmia.

Adolescent↗

Role of inhibitory mechanisms in trigeminal neuralgia.

Segmental inhibition was elicited in the spinal trigeminal nucleus of cats by delivering a conditioning stimulus to the maxillary nerve 100 msec before the test stimulus. Carbamazepine, baclofen, and phenytoin markedly facilitated this segmental inhibition, as well as depressing the response to an unconditioned maxillary nerve stimulus. Phenobarbital, on the other hand, usually depressed the segmental inhibition. These results suggest that drugs that relieve trigeminal neuralgia both facilitate inhibitory mechanisms and depress excitatory mechanisms in the spinal trigeminal nucleus. The facilitation of inhibitory mechanisms appears to be at least as important as the depression of excitatory mechanisms and suggests that a failure of inhibitory mechanisms may play a significant role in the pathogenesis of trigeminal neuralgia.

Animals↗

Baclofen in trigeminal neuralgia: its effect on the spinal trigeminal nucleus: a pilot study.

Experiments with cats showed that baclofen resembles carbamazepine and phenytoin sodium in its ability to depress excitatory synaptic transmission in the spinal trigeminal nucleus. Baclofen was, therefore, given to 14 patients with refractory trigeminal neuralgia. Ten patients were relieved of the paroxysms of tic douloureux while taking 60 to 80 mg/day of baclofen. A reduction in the dosage of baclofen in six of these patients resulted in a recurrence of painful paroxysms in five patients. Seven patients have been pain-free or almost pain-free on a regimen of baclofen for four to 12 months. Our results suggest that baclofen may be a useful drug in the treatment of trigeminal neuralgia and that our experimental model may successfully predict the efficacy of a drug in the treatment of this condition.

Adult↗

Neuropathologic correlation of computerized tomography in Huntington's disease.

CT has proved a useful adjunct to the clinical examination in the differential diagnosis of chorea in adults. The CT abnormalities in cases of Huntington's disease are compared with those of a pathologically verified case of Huntington's disease cut in the CT scan plane of tomography. Relative measurements of caudate atrophy on CT agree well with atrophic processes noted neuropathologically.

Atrophy↗

Hearing loss in carcinomatous meningitis.

Although the syndrome of carcinomatous meningitis presenting as multiple cranial neuropathies is well known, hearing loss as a presenting complaint has not been previously stressed. Five cases of carcinomatous meningitis beginning as hearing loss are presented and the clinical and laboratory features discussed. A thorough review of the literature summarizes the pathology, pathogenesis and recommended modes of therapy of this disease and the importance of early diagnosis and treatment is stressed.

Arachnoid↗

Computed tomography for Huntington's disease.

CT scans of twelve patients with Huntington's disease were compared with a large series of normal and abnormal scans. The frontal horn/bicaudate ratio in the Huntington's disease group was found to be much smaller than and statistically different from the normal or abnormal CT scan groups. The CT scan appears to be a useful adjunct in the evaluation of patients with suspected Huntington's disease.

Adult↗

Myotonic dystrophy and multiple sclerosis.

A 48-year-old man with myotonic dystrophy did well until the age of 37, when he developed the first of many remissions and exacerbations of multiple sclerosis. The only serum value done while the patient was infection free, revealed serum hypogammaglobulinemia. Three determinations of the relative concentration of gama globulin in the cerebrospinal fluid over 11 years, yielded markedly elevated levels. Previous work on the immunological abnormalities in both disease entities is discussed. This is the only published case in which these two diseases were manifested in the same patient.

Humans↗

Unexpected, unexplained death in epileptic patients.

Thirty-seven cases of unexpected, unexplained death in epileptic patients were recorded by the Allegheny County Coroner's Office during the years 1969 through 1973. In no case was there anatomic or chemical evidence at autopsy sufficient to explain death. All patients had a duration of epilepsy greater than a year. All but two had less than one seizure per month. Blood levels of anticonvulsants at autopsy revealed only three patients with therapeutic levels of the drugs. Almost 50 percent of the cases studied had no demonstrable anticonvulsant. It is suggested that inadequate levels of anticonvulsant drugs are a significant factor associated with unexpected, unexplained death in epileptic patients.

Adolescent↗

Comparison of progabide with other antiepileptic and GABAergic drugs.

The effect of the experimental antiepileptic gamma-aminobutyric acid (GABA) agonist drug progabide, [alpha-(chloro-4-phenyl)fluor-5-hydroxy-2-benzilideneamino]-4-buty ramide, on the trigeminal complex of cats was compared with the effect of established antiepileptic drugs and with the effect of various GABA agonists and antagonists. Intravenous administration of 10-40 mg/kg progabide depressed excitatory transmission and descending periventricular inhibition, similar to carbamazepine and phenytoin. However, progabide depressed, rather than facilitated, segmental inhibition. The serum levels of progabide were comparable with those in patients receiving long-term treatment with progabide. The GABA antagonist bicuculline had the opposite effect of progabide on our experimental model, but the other GABA agonists THIP (4,5,6,7-tetrahydroisoxazolo-5,4-C-pyridine-3-ol) and muscimol did not have the same effects as progabide. THIP had no effect on excitatory transmission, periventricular inhibition, or segmental inhibition, whereas muscimol facilitated periventricular inhibition and sometimes segmental inhibition and had no effect on excitatory transmission. Our experiments thus indicate that progabide, but not THIP or muscimol, should have antiepileptic properties, in agreement with the clinical experiences that have been reported. The reason for the differential effect of these three GABA agonists remains to be elucidated.

Animals↗