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Biomedical subjects

S McLean

Publications and source records attributed to S McLean.

At least 145 records · Page 8Linked to original sources
PubMed1982

Determinants of patient compliance and clinical response in general-practice treatment of hypertension.

Self-reported compliance, its relationship with clinical response, and possible determinants of each were examined in 154 general-practice patients who were treated for hypertension. Patient compliance and therapeutic response were highly correlated. Multivariate analyses supported the proposal that (a) relative body weight, drug regimen complexity, and concern at the time of diagnosis were independently influencing patient compliance; (b) compliance was contributing to blood pressure control; and (c) compliance and blood pressure control were each contributing to a lack of concern about hypertension and its risks. Prescribing simple drug regimens, and intentionally increasing the patient's concern at the time of diagnosis may be useful methods to promote compliance with antihypertensive therapy.

Adult↗
PubMed1982

Plasma protein binding of phenytoin in 100 epileptic patients.

The plasma protein binding of phenytoin was investigated in 100 epileptic patients, using equilibrium dialysis at 37 degrees C. The unbound fractions of phenytoin in plasma formed a skewed distribution, with a range of 9.7 to 24.7% and a median value of 12.3%. Most (80%) patients appeared to form one group with free phenytoin fractions from 9.7 to 14.5%, while the remainder formed a group with elevated free fractions (greater than 14.5%). Total and unbound plasma concentrations of phenytoin were strongly correlated (r=0.95, P less than 0.0001). There was a weak correlation between increasing age and the unbound phenytoin fraction (r=0.28, P less than 0.01). The results indicate that measurement of the total phenytoin concentration in plasma should usually provide a reliable index of anticonvulsant effect. However, determination of the unbound phenytoin fraction would be beneficial in the management of those patients in whom this fraction may be elevated, due to interacting drugs or biochemical abnormalities.

Adolescent↗
PubMed1982

Determinants of patient compliance with anticonvulsant therapy.

Determinants of compliance were examined in 101 hospital outpatients with epilepsy. Self-reported patient compliance was associated with plasma anticonvulsant levels, prescription refill frequencies, and appointment keeping. Factors independently related to compliance were worry about one's health, having generalized tonic-clonic seizures, and the absence of barriers to good compliance. Seizure frequency indirectly contributed to patient compliance through worry about one's health. Removing potential barriers to compliance and counselling patients who have been relatively seizure-free may improve compliance with anticonvulsant therapy.

Adult↗
PubMed1981

Determination of therapeutic plasma concentrations of tetrabenazine and an active metabolite by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method for the determination of tetrabenazine and a hydroxy metabolite in plasma is described. Tetrabenazine and the hydroxy metabolite are quantified as their dehydro derivatives using fluorescence detection. This method has been applied to the analysis of plasma samples from patients with Huntington's chorea and has been found to be sensitive, reliable and specific for tetrabenazine and the hydroxy metabolite. The plasma concentrations of tetrabenazine found in patients were lower than could be detected using previously published methods.

Chromatography, High Pressure Liquid↗
PubMed1981

Stability of CNS bindings sites under various conditions.

The effects of (1) method of sacrifice, (2) treatment of tissue and membranes, and (3) gavaging on neurotransmitter receptors were assessed. Most variables did not affect binding, but freezing of forebrain tissue decreased protein recovery and therefore estimates of binding sites per brain weight. Serotonin binding was especially sensitive to freezing to neurotoxicology is discussed.

Animals↗
PubMed1979

Intracranial self-stimulation thresholds: a model for the hedonic effects of drugs of abuse.

We present the thesis that many drugs of abuse are used for their hedonic effects and that a relevant animal model for the study of these effects is the action of these drugs on the pathways that support rewarding intracranial self-stimulation. A relationship between abuse potential of a drug and its ability to lower the threshold for rewarding brain stimulation in the rat was found. Of all the compounds we have studied, morphine and cocaine were the drugs that caused the maximum lowering of the rewarding threshold. Phencyclidine hydrochloride and the mixed agonist-antagonist pentazocine also lowered the threshold to a lesser degree, while the mixed agonist-antagonists cyclazocine and nalorphine hydrochloride had inconsistent effects. Naloxone hydrochloride, at the doses tested, had no effect on the threshold. Further, there is no evidence that tolerance develops to the threshold-lowering effect of morphine, suggesting that continued use of narcotics by the physically dependent individual is not simply due to an effort to avoid the pain of withdrawal.

Animals↗
PubMed1978

Metabolism of phenacetin and N-hydroxyphenacetin in isolated rat hepatocytes.

The fate of phenacetin and some of tis metabolites have been examined in isolated rat hepatocytes. The overall pattern of metabolism was similar to that found in vivo by others. The major metabolites of phenacetin were paracetamol, free and conjugated, and phenetidine, and about 10% was lost. No N-hydroxyphenacetin was found, but experiments with N-hydroxyphenacetin as substrate showed that at low concentration (as might be formed from phenacetin) it disappeared very rapidly from cell suspensions. N-hydroxyphenacetin was metabolized to its conjugates, and to paracetamol, phenacetin and phenetidine, with a large proportion unaccounted for. With all substrates, increasing concentration resulted in a decreased percentage being metabolized, indicating that the metabolic pathways were saturable. Relatively more phenetidine was found at high phenacetin concentrations, however, apparently because phenetidine is an intermediate metabolite whose own elimination was slowed relatively more than its formation. N-hydroxylated arylamines were toxic to hepatocytes in a dose-dependent manner, suggesting that these cell suspensions could be used to test for hepatotoxicity.

Acetaminophen↗
PubMed1978

Young adult, geriatric and aphasic group responses to simple analogies.

The efficiency of interactive language processing was compared in three groups: 25 young adults, 25 geriatric subjects, and 25 adult aphasic subjects. The task involved simple analogy completion. Data analysis included six categories of responses which represetned levels of convergence toward the expected relationships. Results of chi-square comparisons between groups were all significant, and indicated substantial reductions in interactive processing for geriatric subjects. The findings suggest that a general aging factor may contribute to the poor prognosis in elderly aphasic patients.

Adult↗