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Biomedical subjects

R W Homan

Publications and source records attributed to R W Homan.

27 records · Page 2Linked to original sources
PubMed1983

Single-proton tomographic study of regional cerebral blood flow in epilepsy. A preliminary report.

Regional cerebral blood flow (rCBF) may be measured with a single-photon-emission computed tomograph (SPECT) after inhalation of xenon 133. Our SPECT studies of rCBF in a group of 18 patients with seizure disorders, when compared with studies in 32 normal control subjects, have shown enhanced flow to an active seizure focus and ischemia of brain areas in certain subjects between seizures. Thus, SPECT determination of rCBF has demonstrated a number of findings recently observed with positron-emission tomography and may become a useful modality in the study of patients who have epilepsy.

Adolescent↗
PubMed1983

Clinical studies of lorazepam in status epilepticus.

The collective clinical data support the concept that lorazepam is highly effective for a broad range of seizure types, with the major inadequacy being in myoclonus, a seizure type typically highly resistant to other anticonvulsants as well. In addition to its effectiveness, lorazepam appears to have two other major advantages; a prolonged duration of action, which makes frequent or continuous administration unnecessary, and a high degree of freedom from serious side effects involving either the respiratory or cardiovascular system. Although experience at this time is insufficient to allow a firm statement concerning effective concentrations, such concentrations appear readily achievable in most patients with injections of 4 to 5 mg. Lorazepam appears to meet all the requirements of an anticonvulsant useful for treatment of status epilepticus and should prove to be a major drug in the treatment of this condition.

Adolescent↗
PubMed1981

Alpha-pattern coma in a 2-month-old child.

A 2-month-old infant is described in whom the electroencephalographic finding of alpha-frequency activity was correlated with a clinical state of unresponsiveness. This condition occurred following a period of hypoxia and was similar to alpha-patter coma in adults. The finding of alpha-pattern coma in a young infant suggests that alpha-frequency activity in comatose states in abnormally generated since alpha-frequency activity normally is not found in this age group.

Alpha Rhythm↗
PubMed1980

Phenytoin plasma concentrations in paroxysmal kinesigenic choreoathetosis.

We studied five patients with paroxysmal kinesigenic choreoathetosis (PKC) to evaluate the minimum effective plasma concentration of phenytoin. In two children, the minimum concentration necessary to control symptoms approximated the concentrations necessary to control epileptic seizures. In three adults, symptoms were controlled with concentrations of phenytoin well below the therapeutic range of phenytoin in epilepsy. These findings suggest an age-dependent change in the disease state, and support the concept that the clinical course of PKC may be explained by delayed maturation of extrapyramidal systems.

Acetylcholine↗
PubMed1979

Lorazepam in status epilepticus.

Lorazepam, a dichloro-3-hydroxy-1,4-benzodiazepine, has been shown to be a potent anticonvulsant in animal models of epilsepsy and has minimal depressant effects on respiration and circulation in humans. The effects of this compound were studied in status epilepticus. Twenty-five patients were given intravenous lorazepam during status epilepticus of varying cause. Four or 8 mg of the drug controlled status in 22 of the 25 patients. Although single seizures recurred in 5 of the 22 patients, none experienced recurrence of status during a prolonged follow-up period. Transient respiratory arrest occurred in 1 patient, but no other significant complications were observed. Studies of plasma drug levels suggest that most patients attain good seizure control at concentrations between 30 and 100 ng per milliliter. Clinical observations indicate that repetitive injections are not required for continuing control of seizures in patients whose seizures are initially controlled. Lorazepam appears to be an effective and safe drug for treatment of status epilepticus, with a duration of control longer than that achieved with diazepam.

Adolescent↗
PubMedDate not supplied

Kindled seizures elevate blood pressure and induce cardiac arrhythmias.

The effect of kindled seizures on the cardiovascular system was examined in amygdaloid kindled rats. The most prominent cardiovascular response during a generalized kindled seizure was an abrupt 50% increase in mean arterial pressure (MAP) lasting 20-30 s after initiation of the seizure. Superimposed on this change in blood pressure (BP) was a profound bradycardia characterized by a rate about half that recorded before stimulation. Changes in heart rate (HR) and BP observed during amygdaloid kindled seizures were similar to those observed during secondary spontaneous seizures. These effects apparently are independent of the kindling stimulus because stimulus-induced cardiovascular changes were not present at the beginning of the kindling process. These results suggest that the kindling seizure model is useful to study the underlying mechanisms of seizure-induced cardiac arrhythmias and possibly the clinical phenomenon of sudden unexplained death in epileptic patients.

Animals↗
PubMedDate not supplied

Single-photon tomographic determination of regional cerebral blood flow in epilepsy.

Using a single-photon emission computed tomographic scanner (SPECT) the authors determined regional cerebral blood flow (rCBF) with inhaled xenon-133, a noninvasive procedure. Studies were performed in 40 normal individuals, and these were compared with rCBF determinations in 51 patients with seizure disorders. Although positive results were obtained in 15 of 16 patients with mass lesions, the group of principal interest comprised 25 patients suffering from "temporal lobe" epilepsy. Only one of these had a positive x-ray computed tomogram, but 16 had positive findings on rCBF study. These findings included increased local blood flow in the ictal state and reduced flow interictally.

Adolescent↗