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Biomedical subjects

E A Rodin

Publications and source records attributed to E A Rodin.

At least 19 recordsLinked to original sources
PubMed1991

Some problems in the clinical use of topographic EEG analysis.

The correct clinical use of topographic EEG analysis is labor intensive, time consuming and does not bypass the problems involved in conventional EEG interpretations. The physician interpreting maps needs not only to be fully cognizant of all the aspects of clinical electroencephalography but also of the special issues inherent in this methodology. Certain problems that are specific to topographic EEG analysis and that can lead to wrong interpretations are presented.

Brain Mapping↗
PubMed1989

Derivation and evaluation of an equation for prediction of free phenytoin concentration in patients co-medicated with valproic acid.

The relationship between free phenytoin fraction (F-PHT-F) and valproic acid (VPA) was studied under two conditions: (a) in serum samples from 43 institutionalized patients (212 serial data points) at plateau steady state, and (b) in plasma samples from 50 outpatients coming for regular visits to our clinic throughout the day. Results for both groups led to identical linear regression equations relating F-PHT-F to VPA: F-PHT-F = 0.095 + 0.001 (VPA). Nevertheless, as expected, the resulting equation gave an unreliable prediction of F-PHT-F due to a variable physiological matrix. Substituting the parameter F-PHT-F by its equivalent (F-PHT/PHT) gave the equation F-PHT = [0.095 + 0.001 (VPA)] PHT. The predictive power of this equation was evaluated by the comparison of obtained and predicted F-PHT concentrations. For the combined patient group (n = 93), an excellent agreement (r = 0.972 and F = 999.9; p less than 0.001) was obtained. Although the empirically derived constants of the equation are not unique and may vary depending on the conditions of different methodologies, the fundamental relationship has been established and can be used to reliably predict F-PHT concentration from plasma VPA and PHT concentrations.

Adult↗
PubMed1989

Derivation and evaluation of an equation for prediction of free carbamazepine concentrations in patients comedicated with valproic acid.

The relationship between free carbamazepine fraction (F-CBZ-F) and valproic acid (VPA) was studied in 50 outpatients coming for regular visits to our clinic throughout the day, and was compared with 50 patients without VPA comedication under similar conditions. F-CBZ-F was found to be significantly (t = 3.5, df = 98, p less than 0.001) higher for VPA comedicated patients (0.291 +/- 0.024) when compared with patients without VPA (0.247 +/- 0.016). Linear regression analysis for total plasma VPA concentration versus F-CBZ-F gave the equation: F-CBZ-F = 0.247 + 0.00062 (VPA); n = 50, r = 0.697, p less than 0.001, indicating unreliable prediction of F-CBZ-F from VPA concentration. Substituting the parameter F-CBZ-F by its equivalent (F-CBZ/CBZ) yielded the equation F-CBZ = [0.247 + 0.00062 (VPA)] CBZ. The predictive power of this equation was evaluated by the comparison of obtained and predicted F-CBZ concentrations. An excellent agreement (n = 50, r = 0.981, p less than 0.001) was obtained. Although the empirically derived constants of the equation are not unique and may vary depending on the conditions of different methodologies, the fundamental relationship has been established and can be used to reliably predict F-CBZ concentration from plasma VPA and CBZ concentration.

Adolescent↗
PubMed1987

Chronic antiepileptic drug therapy: classification by medication regimen and incidence of decreases in serum thyroxine and free thyroxine index.

Results are described on the association of decreased serum total thyroxine (T4) and free thyroxine index (FTI) with antiepileptic drug therapy in a group of randomly selected chronically medicated outpatients (n = 291). For monotherapy subgroups (n = 164), the highest incidence (T4, 23.9%; FTI, 25.4%) of below normal values occurred in patients medicated with carbamazepine (CBZ), followed by phenytoin [(PHT) T4, 13.2%; FTI, 7.9%], and phenobarbital [(PB) (T4, 3.4%; FTI, 0%]. No T4 and FTI values below normal were detected in any patients (n = 30) on chronic valproic acid (VPA) monotherapy. For CBZ monotherapy (n = 67), women (n = 37) had a higher frequency of below normal values of T4 (p less than 0.05) and FTI (p less than 0.001) than men (n = 30). Therefore, the order of decreasing T4 and FTI effect was as follows: CBZ (women) greater than CBZ (men) greater than PHT greater than PB greater than VPA. For polytherapy subgroups (n = 127), the highest incidence (T4, 51.9%; FTI, 48.1%) was found in patients medicated with PHT and CBZ, followed by PHT and VPA (T4, 37.0%; FTI, 23.9%), and PHT and PB (T4, 17.2%; FTI, 10.3%). For PHT and CBZ poly-therapy (n = 52), women (n = 21) had a higher frequency of below normal values of T4 (p less than 0.05) and FTI (p less than 0.001) than men (n = 31). The magnitude of the decreasing T4 and FTI effect was greater for polytherapy subgroups (versus monotherapy subgroups) and in order as follows: PHT + CBZ (women) greater than PHT + CB (men) greater than PHT + VPA greater than PHT + PB.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Intellectual functions of patients with childhood-onset epilepsy.

The intellectual functions of 64 epileptic patients who had had an initial evaluation between five and 16 years of age, including the WISC, were re-evaluated after a period of at least five years. In general the seizure states had improved, and 50 per cent were in remission for between two and eight years. All but four were still taking at least one anticonvulsant drug. WISC IQ estimates showed a slight decrease. Verbal and performance areas could be differentially affected, and a gain in one could be offset by a loss in the other, so the Full-scale IQ might not be a reliable measure of day-to-day performance. Those whose seizures remained uncontrolled had a statistically significant decrease in performance IQ, whereas in general it was stable or increased for patients in remission. There was evidence that decreased IQ indicated slower mental growth rather than loss of previously acquired function. Phenobarbital but not phenytoin levels were inversely correlated with IQ, suggesting that the upper limit of the 'therapeutic range' of phenobarbital may already be toxic with regard to learning abilities. To optimize an epileptic child's functioning in school and to prevent long-term intellectual problems, it is advisable that IQ testing should be part of the routine initial evaluation, and that drug levels should be checked at regular intervals.

Adolescent↗
PubMed1985

Chronic valproic acid therapy and incidence of increases in venous plasma ammonia.

Results are described on the association of elevated ammonia (NH3) with valproic acid (VPA) therapy in a large group (n = 157) of randomly selected, chronically medicated (greater than 2 years) outpatients. The highest incidence (45.5%) of elevations occurred in patients comedicated with VPA-phenobarbital (PB)-phenytoin (PHT) combinations, followed by VPA-PB (33.3%) and VPA-PHT (15.4%). No NH3 elevations were detected in all patients (n = 38) on chronic VPA monotherapy. Considering the total sample (n = 157), NH3 concentrations were found to be linearly and directly correlated with VPA plasma concentration (n = 125, r = 0.249, p less than 0.001), PB concentration (n = 86, r = 0.411, p less than 0.001), sum of VPA-PB concentration (n = 60, r = 0.721, p less than 0.001), and sum of VPA-PB-PHT concentration (n = 33, r = 0.802, p less than 0.001). When patients in the subgroups (n = 73) that included all the patients with elevated NH3 were separated into one group (n = 47) with normal NH3 (less than or equal to 0.70 micrograms/ml) and one group (n = 26) with elevated NH3 (greater than or equal to 0.71 micrograms/ml), Student's t tests for equality of means showed that the group with elevated NH3 had a significantly higher mean plasma concentration for VPA, PB, sum of VPA-PB, and sum of VPA-PB-PHT (all at p less than 0.001) when compared with the normal group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Effect of phenothiazines on serum antiepileptic drug concentrations in psychiatric patients with seizure disorder.

The intrapatient effect of starting (group A, n = 16), increasing (group B, n = 19), decreasing (group C, n = 23), and discontinuing (group D, n = 34) the phenothiazines (PHZs) thioridazine, chlorpromazine, or mesoridazine on serum phenytoin (PHT), phenobarbital (PB), and primidone (PRI) was studied at a constant antiepileptic drug regimen and between two consecutive steady-state concentration determinations in 92 institutionalized epileptic patients with psychiatric disorders. For PHZ initiation or dosage increase (groups A and B), serum PHT and PHT concentration-to-dose ratio (C/D) decreased by 44 (p less than 0.001) and 41.6% (p less than 0.001) in group A, and 32.9 (p less than 0.001) and 35.3% (p less than 0.005) in group B, respectively. For PHZ dosage decrease or discontinuation (groups C and D), serum PHT and C/D ratio increased by 54.8 (p less than 0.001) and 51.3% (p less than 0.01) in group C, and 71.2 (p less than 0.001) and 69.2% (p less than 0.001) in group D, respectively. The changes for PB were in the same direction, although to a lesser extent. No statistically significant differences were noted for PRI. For groups A and B, the clinical trend was for increase in number of seizures when PHZs were started or dosage increased. For groups C and D, a clear trend for PHT intoxication was evident when PHZ dosages were decreased or discontinued.

Adolescent↗
PubMed1981

Clorazepate therapy for refractory seizures.

We treated 61 patients with seizures refractory to conventional anticonvulsants by adding clorazepate to their regimen. There was some improvement of seizure control, but no overall improvement in the electroencephalogram. Improvement of seizure control was not significantly related to seizure type. No significant side effects, drug interactions, or laboratory abnormalities were noted with doses up to 3 mg per kilogram per day.

Adolescent↗
PubMed1980

Monitoring clorazepate dipotassium as desmethyldiazepam in plasma by electron-capture gas--liquid chromatography.

We describe a procedure for determing clorazepate dipotassium as its decarboxylated, pharmacologically active metabolite, desmethyldiazepam, in 100 microL of plasma, with use of electron-capture gas--liquid chromatography and with methylnitrazepam as the internal standard. The procedure is a one-tube, one-step extraction without derivative formation and is accurate, reproducible, and rapid. The sensitivity limit is 20 micrograms/L. Within-run and between-run CV's (concentration, 3.5 mg/L) were 2.9 and 3.5%, respectively. Within-run CV's for 1.5 and 1.0 mg/L concentrations were 3.9 and 4.3%, respectively. For a 1.0 mg/kg per day dose of clorazepate dipotassium, the mean steady-state concentration of desmethyldiazepam in plasma was 1.037 mg/L.

Anti-Anxiety Agents↗
PubMed1976

A comparison of the effectiveness of primidone versus carbamazepine in epileptic outpatients.

Prior to the release of carbamazepine for the treatment of patients with psychomotor and grand mal seizures, primidone was regarded as the drug of choice for these disorders, especially when combined with diphenylhydantoin (DPH). It was, therefore, of interest to compare the effectiveness of carbamazepine against primidone when added to a therapeutic dose of DPH. Forty-five patients completed a 6-month study with each patient serving as his own control. The patients were initially stabilized on therapeutic doses of DPH and one of the test compounds, while all other medications were withdrawn. After 3 months of treatment, they were transferred onto the other drug for a second 3-month period. Extensive laboratory testing, including anticonvulsant levels, electroencephalograms, and neuropsychological evaluations, was performed. For the most part, the patients remained on outpatient status, returning for reports of seizure frequency, side effects, and laboratory studies every 14 days. The study was conducted in a single blind fashion by the treating neurologists; double blind by the electroencephalographer and psychologists. The results indicated that the two drugs did not differ in their effectiveness on seizure control. There were somewhat more side effects--none serious--with carbamazepine than with primidone. The EEG showed increased fast activity with primidone and increased theta activity with carbamazepine. There was no difference in regard to decrease of electroencephalographic seizure discharges. The patients showed more impairment on a repeatable neuropsychological test battery with primidone than with carbamazepine, and they also showed an increase on the psychopathic deviate scale of the Minnesota Multiphasic Inventory. Depressive feelings, when present, lessened while under treatment with carbamazepine. The results suggest that patients with the seizure types under consideration and who do not respond to DPH alone or to a DPH-phenobarbital combination can be placed on either carbamazepine or primidone while phenobarbital is discontinued. A patient who is intellectually and emotionally intact with no past history of behavioral disturbances may do better on primidone than carbamazepine, because this drug gives fewer side effects. On the other hand, those patients who have a past history of emotional and/or intellectual disturbances may profit more from carbamazepine.

Adolescent↗
PubMed1976

Differences between patients with temporal lobe seizures and those with other forms of epileptic attacks.

Seventy-eight patients with temporal lobe type seizures were precisely matched for age, sex, and Wechsler I.Q. levels with patients suffering from other seizure types. Statistically significant differences were established between the groups in regard to treatment response, etiologies, and behavioral variables. Further analysis of the data showed that the behavioral problems of the temporal lobe patients were present only in that group that suffered from more than one seizure type. That temporal lobe epilepsy group having only one seizure type differed from the controls with one seizure type in regard to etiological factors; they actually showed better performance on certain subscales of the WAIS, as well as better employment records. The clinical impression of the temporal lobe epilepsy patient usually presenting more difficulties than other patients with epilepsy results from the fact that the temporal lobe patients have, in the overwhelming majority of instances, more than one seizure type.

Adolescent↗