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Biomedical subjects

J M Pellock

Publications and source records attributed to J M Pellock.

At least 91 records · Page 5Linked to original sources
PubMed1985

Postictal pulmonary edema in children.

Pulmonary edema complicating generalized tonic-clonic seizures has rarely been reported in children, although it has been well documented in adults. We report two patients, aged 8 and 9 years, who developed clinical and radiographic evidence of the condition. Fever, leukocytosis, and arterial hypoxemia are seen in the absence of cardiac dysfunction or infection. Rapid and complete recovery is to be expected if supportive therapy is instituted. Since these patients had no underlying cardiac pathology, control of the seizures will prevent further episodes.

Carbamazepine↗
PubMed1985

Pyridoxine deficiency in children treated with isoniazid.

Isoniazid-induced deficiency of pyridoxine (vitamin B6) is reportedly not uncommon in adults but rare in children. In the present study, 38 children had serum levels of pyridoxine tested while receiving therapy with isoniazid. A biologic assay using the protozoan Tetrahymena thermophila determined pyridoxine status after 2 to 18 months of therapy with isoniazid. Five children (13 percent) were deficient. None had definitive clinical symptoms or signs consistent with pyridoxine deficiency. Three had normal nerve conduction velocity. Children receiving isoniazid in dosages greater than 10 mg/kg/day had a higher incidence of deficiency. Present recommendations for withholding pyridoxine prophylaxis from children receiving isoniazid therapy must be reconsidered in light of these findings, particularly in those children who are debilitated or have a poor nutritional history with a known pyridoxine deficit prior to therapy with isoniazid.

Child↗
PubMed1981

Effect of antacids on phenytoin bioavailability.

Eight subjects were studied in a randomized crossover design to determine the effect of aluminum-magnesium hydroxide (AMH), calcium carbonate (CC), and aluminum hydroxide-magnesium trisilicate (AHMT) on the bioavailability of a single, 600-mg dose of phenytoin administered orally. Each subject received phenytoin alone on two separate occasions and phenytoin plus each of the three antacids on three other occasions. Each antacid was administered as 160 mEq at 1 and 3 hr after each meal and at bedtime on the day phenytoin was given. The mean area under the curve (AUC) was significantly decreased by AMH (p less than 0.005) and CC (p less than 0.05). AHMT had a similar trend but did not reach statistical significance (p = 0.1). Large inter- and intrasubject variability in AUC was observed when phenytoin was administered alone. In two subjects, cumulative urinary 5-(4-hydroxyphenyl)-5-phenylhydantoin at 72 hr (HPPH72) was determined. The amount of HPPH recovered had similar trends as the AUC with antacid treatments but not the same magnitude. In this study, antacids altered not only the extent of absorption but also appeared to alter the rate of absorption. Antacids administered in a peptic ulcer regimen may decrease the AUC of a single dose of phenytoin. Patients should be cautioned against concomitant use of antacids and phenytoin.

Adult↗
PubMed1981

Effects of food on valproic acid absorption.

The effect of food on valproic acid absorption was investigated in a randomized, cross-over study with eight subjects. Two 250-mg soft-gelatin capsules of valproic acid were administered to the participants under fasting and nonfasting conditions. The time of peak serum concentration, height of the peak concentration, and total area under the curve were determined and compared by the Student's t test for paired data. The time to attain a peak serum concentration was significantly delayed (p less than 0.005) from the 1.6 hours during fasting conditions to four hours after a standard meal. A statistically insignificant trend toward lower peak serum concentrations (54.6 micrograms/ml versus 49.4 micrograms/ml) was found under the nonfasting conditions. This trend becomes significant if the data of one subject who exercised before taking the drug are eliminated. The area under the curve was not different between the two conditions. The administration of the drug with food did not significantly alter the volume of distribution, half-life, or elimination constant. No clinically important interaction resulted from the administration of valproic acid with food. If a patient experiences gastrointestinal side effects with valproic acid, the patient may be advised to take the drug with food.

Adult↗
PubMed1980

Childhood hypertensive stroke with neurofibromatosis.

A child with neurofibromatosis had hypertension and acute hemiplegia resulting from both renal and cerebral vascular occlusive disease. This case illustrates the importance of recognizing surgical antihypertensive therapy was attempted, and may have contributed to rapid neurologic deterioration. Children with neurofibromatosis and hypertension require a careful neurologic evaluation, including computed tomography, before therapy.

Arterial Occlusive Diseases↗
PubMed1978

Periventricular leukomalacia related to neonatal anoxia: recognition by computed tomography.

Periventricular areas of decreased attenuation coefficient were demonstrated by computed tomography (CT) in two infants with neurological involvement after episodes of neonatal hypoxia. This CT finding is related to anoxic periventricular leukomalacia, which is well documented in the literature. Follow-up CT scans in our two patients demonstrated reversibility of the white matter changes.

Brain Diseases↗
PubMedDate not supplied

Pharmacokinetics and safety of lamotrigine (Lamictal) in patients with epilepsy.

In a double-blind parallel study, patients with epilepsy on stable regimen of antiepileptic drugs (AEDs) were given lamotrigine (8 pts) or placebo (3 pts). Patients were sequentially dosed with 100, 200 and 300 mg/day given as a b.i.d. regimen. After steady state was achieved, timed plasma lamotrigine levels were obtained post dose. No medical, psychogenic, neurologic, or hematologic changes were observed and no subjective effects were detected as a result of treatment with lamotrigine. No changes in heart rhythm or blood pressure were observed related to lamotrigine. Pharmacokinetic parameters were calculated using 1-compartment and non-compartment models. The results were similar using both models. Area under the plasma concentration vs. time curves increased linearly with dose. Mean half life (13.5 h), volume of distribution (1.36 l/kg) and clearance (1.27 ml/min/kg) were similar to previously reported results and did not change with increasing dose. These findings indicate that lamotrigine pharmacokinetics can be described by the 1-compartment model, has linear kinetics, and does not induce its own metabolism in patients on concomitant AEDs.

Adolescent↗
PubMedDate not supplied

Single dose comparison of the relative bioavailability of phenytoin suspension and extended capsules.

There is presently only one preparation of phenytoin approved for once-daily dosing--extended phenytoin sodium capsules. We have observed many hospitalized patients switched from either this preparation or the intravenous form of phenytoin to phenytoin oral suspension. The bioavailability and single dose pharmacokinetics of extended phenytoin sodium capsules (Dilantin Kapseals) and phenytoin oral suspension (Dilantin oral suspension) were compared in seven healthy adult volunteers. Each subject was administered both three 100-mg Dilantin Kapseals (276 mg free acid) and 11 ml (275 mg) Dilantin-125 oral suspension in a randomized cross-over design with a 1-week washout period between preparations. Blood samples were drawn over 78 h after the administration of each preparation for determination of serum phenytoin concentration. In addition, total urinary output was collected for 48 h. Statistical analysis consisted of a comparison of the area under the curve (AUC) from time zero to 48 h and time-to-peak concentration using a two-tailed paired t test at a level of significance of p less than 0.05. The total alpha level was 0.10. No significant differences were found between the two preparations. The power of detecting a 15% difference in AUC was 0.80, and the power of detecting a 5-h difference in time to peak was 0.52. Following is a summarization of the pharmacokinetic parameters (capsules mean +/- 1 SD; suspension mean +/- 1 SD).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗