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Biomedical subjects

C M Swartz

Publications and source records attributed to C M Swartz.

At least 73 records · Page 4Linked to original sources
PubMed1991

Determination of drug half-life while giving doses between blood samples.

Traditional methods of determining drug elimination half-life require that no doses be given between the blood samples, which delays drug administration. This article details a new method to determine drug half-life from blood samples drawn with intervening drug doses, that is, while blood levels are building rather than falling. This method was derived from one-compartment pharmacokinetic modeling to assist regulation of doses of central nervous system drugs whose blood concentrations have clinical meaning, for example, lithium and some antidepressants. It should improve the accuracy and practicality of pharmacokinetic methods to predict desirable steady-state drug doses at start-up and to monitor the total daily drug exposure during followup.

Half-Life↗
PubMed1990

Albumin decrement in depression and cholesterol decrement in mania.

Within all psychiatric inpatients over a 4-year period, on admission depressives showed serum albumin 5.4% lower (P less than 0.001) than non-psychiatric controls. Similarly, manics showed cholesterol 10% lower (P less than 0.0005) and serum calcium/protein ratio 2.2% higher (P less than 0.05) than controls. These deviations suggest a tendency towards dietary aberrations in these patients of potential medical significance. These tests had shown the most distinct variation with diagnosis on split-half discriminant function analysis of routine chemistry and hematology tests of 107 patients with mania, 132 with depression, 67 with schizophrenia, 18 with schizoaffective illness, and 83 non-psychiatric controls admitted for elective surgery.

Adult↗
PubMed1990

Electroconvulsive therapy emergence agitation and succinylcholine dose.

In this prospective study, five patients who had repeatedly shown troublesome restless emergence agitation after each of 20 sessions of electroconvulsive therapy (ECT) with a succinylcholine dose about .7 mg/kg showed no agitation after 15 ECT sessions in which the succinylcholine dose was increased to about 1.0 mg/kg. The probability that the pattern of response to higher succinylcholine dose resulted from random processes is less than .005. This provides evidence that patients predisposed to emergence agitation are sensitive to seizure-induced metabolic changes in skeletal muscle tissue and that the likelihood of emergence agitation rises with the ratio of skeletal muscle mass to succinylcholine dose. Because ECT-inducted serum lactate elevations are blocked by succinylcholine, emergence agitation might be essentially the same phenomenon as lactate-induced panic.

Adult↗
PubMed1990

Multiple muscle enzyme release with psychiatric illness.

Associations (p less than .001) between serum concentrations of lactate dehydrogenase (LDH) and glutamic oxaloacetic transaminase (SGOT) were observed in physically well patients with mania (N = 100, r = .70), depression (N = 138, r = .51), chronic schizophrenia (N = 85, r = .68), and schizoaffective or atypical psychosis (N = 39, r = .52) discharged from 1978 through 1981. In contrast, there was a negligible association between these enzymes in 90 nonpsychiatric inpatient control subjects. Patients with mania (229.0 +/- 106.1 IU/l) showed significantly (t = 3.16, p less than .002, two-tailed) higher lactate dehydrogenase (LDH) levels than control subjects (191 +/- 41.7 IU/l) and a 14% incidence of abnormally high serum LDH levels vs. 1% among control subjects. Results were unchanged when patients taking neuroleptics were excluded. These results indicate that psychiatric illness, especially mania, induces release of LDH and SGOT, occasionally to unusually high levels. This is similar to previous reports of muscle creatine phosphokinase release in psychiatric patients. Presumably, these enzymes are released from skeletal muscle in association with agitation, with muscle tension, or with blood stasis and local tissue hypoxia consequent to hypoactivity.

Aspartate Aminotransferases↗
PubMed1990

Serum prolactin levels during extended cocaine abstinence.

Following a report indicating almost a 100% risk for hyperprolactinemia in cocaine users after 1 month of abstinence, the authors determined the serum prolactin concentrations of 23 male inpatients who had abstained from cocaine for 2-43 weeks. None showed high prolactin levels; this places the incidence below 12.3% with 95% confidence. These results imply that persistent hyperprolactinemia requires a medical explanation other than cocaine abstinence itself.

Bromocriptine↗
PubMed1990

Blood pressure reduction with ECT response.

A group of 48 male inpatients who responded to electroconvulsive therapy for major depression showed decreases in resting blood pressure along the course of treatment. Decreases occurred in both systolic (mean +/- SD = 8.0 +/- 17.3 mm Hg, p = .0025) and diastolic (7.4 +/- 13.2 mm Hg, p = .00030) pressures. Systolic pressure decreased by at least 20 mm Hg in 15 patients. These findings are consistent with reports that depressives show elevated plasma catecholamine levels, and that, with response to tricyclic antidepressants, their blood pressures decrease. Depression-associated blood pressure elevation might contribute to the excessive cardiac mortality of depressives; conversely, antidepressant treatment might control hypertension in some depressives.

Antidepressive Agents, Tricyclic↗
PubMed1989

Correction of blood drug levels for changes over the day.

A graph-based method is presented to compensate for the influence of variations in drug dosage schedules and blood sampling times upon the blood concentrations of drugs whose elimination half-life is between 7 and 48 hours. This method permits the clinician to interpret blood drug levels drawn at nonstandard times, and to correct blood drug levels for how the daily dose was divided. This method is expected to improve the convenience of monitoring blood drug levels.

Blood Specimen Collection↗
PubMed1989

Pharmacologic provocation and dexamethasone suppression test sensitivity.

In expectation of improving sensitivity, the standard 1-mg dexamethasone suppression test (DST) was given to 10 depressed inpatients and repeated with theophylline or caffeine and again following 3 days of lorazepam with abrupt discontinuation. Two patients showed nonsuppression on the standard DST; 2 suppressors changed to nonsuppression after lorazepam discontinuation, and 1 also changed after theophylline. This increase from 20 to 40% sensitivity remains significantly less than a desirable minimum 80% sensitivity (p less than 0.001), which suggests that a consistent DST sensitivity of 80% in melancholia is unlikely to be attained.

Caffeine↗
PubMed1989

Differential effects of right unilateral and bilateral ECT on heart rate.

In a series of 11 melancholic patients who received both right unilateral and bilateral ECT during a single course of treatment, mean and minimum postictal heart rates were greater after bilateral ECT. Greater catecholamine release during bilateral ECT is the most likely explanation for these effects. These differences complement other evidence that bilateral ECT has a more pronounced physiological impact than unilateral ECT.

Catecholamines↗
PubMed1989

Antidepressant effects of right versus left unilateral ECT and the lateralization theory of ECT action.

In a random-assignment, double-blind, controlled comparison of right versus left unilateral ECT in 30 melancholic men, the two methods were not significantly different in overall antidepressant potency, although there was a significantly faster rate of improvement with left unilateral ECT. These results imply that the antidepressant effects of ECT cannot be attributed primarily to right hemisphere mechanisms, as others have postulated.

Adult↗
PubMed1988

Cell surface oligosaccharide modulation during differentiation: III. Lectin affinity class distributions.

In previous studies we showed that the onset of the morphological phenotype of cellular senescence (IMR-90) in vitro is preceded by complex cell surface changes. Using fluorescently conjugated lectins these studies showed: (1) quantitative PDL-dependent decreases in cell surface mannosyl, galactosyl, and N-acetyl-glucosamine residues; (2) these changes were correlated with changes in ligand/lectin membrane mobility, suggesting a functional relationship for the quantitative changes. To further investigate the biological significance of these observations we have developed a synthetic ligand competition assay to analyze the lectin binding event itself. The results of these analyses show that: (1) the number of binding affinity class distributions is highly restricted; (2) the PDL-dependent mannosyl change is due to the loss of a high-affinity class distribution without significant change in the low-affinity site; and (3) PDL-dependent changes in both galactosyl and N-acetyl glucosamine binding events are the result of changes in the affinity class distributions. These results are interpreted in terms of the potential available energy to act as the basis for signal transduction at the cell surface.

Binding, Competitive↗