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Biomedical subjects

P Jatlow

Publications and source records attributed to P Jatlow.

At least 73 records · Page 4Linked to original sources
PubMed1980

Is cocaine a sympathetic stimulant during general anesthesia?

Eighteen patients undergoing coronary artery surgery were observed to examine whether cocaine in a clinically used dose exerts sympathomimetic effects during general anesthesia. Eleven patients received cocaine hydrochloride as a 10% solution (1.5 mg/kg) applied topically to the nasal mucosa before nasotracheal intubation. Seven patients had a similar procedure without cocaine. Blood pressure, pulse rate, cardiac index, left ventricular stroke work index, total peripheral vascular resistance, and pulmonary vascular resistance were measured. There were no important differences in cardiovascular function between patient groups. The rapid rise in plasma cocaine concentration, reaching 331 ng/mL at 30 minutes and 320 ng/mL at 45 minutes, bore no apparent relationship to any changes in cardiovascular function. We conclude that under conditions of this study, administration of topical cocaine does not exert any clinically significant sympathomimetic effect and appears to be well tolerated in anesthetized patients with coronary artery disease.

Administration, Topical↗
PubMed1980

Kinetics of bilirubin photodegradation with application to amniotic fluid.

By spectrophotometric methods we have studied the photodegradation of bilirubin in simple solution and in amniotic fluid and have found that: (1) the photodegradation process can be described by kinetics which are first-order in concentration and second-order in time; (2) the photodegradation products of bilirubin do not prevent the determination of the absorbance of the parent compound; (3) although the rate of the photodegradation process depends upon both the oxygen partial pressure and the irradiation intensity, the determination of the original bilirubin absorbance is independent of both of these parameters so long as they are constant over the period of photodegradation; (4) other chromagens in amniotic fluid (including hemoglobin and methemoglobin) experience little photodegradation in the time required to degrade bilirubin; (5) several absorbance measurements over a short (approximately five-minute) period of photodegradation are sufficient for the determination of the original bilirubin absorbance for the complete range of interest in amniotic fluid with an accuracy of about five percent.

Amniotic Fluid↗
PubMed1980

Platelet MAO and amitriptyline treatment.

Some tricyclic antidepressants have been reported to inhibit monoamine oxidase (MAO) activity in vitro in addition to blocking the reuptake of norepinephrine and/or serotonin. While the inhibition of MAO is reversible, platelet MAO activity in depressed patients responding to amitriptyline treatment has been reported to be reduced after drug treatment. In a reverse design, we measured platelet MAO activity and drug levels in patients chronically being treated with amitriptyline and again 2 and 4 weeks after stopping the medication. Although tricyclic drug concentrations were initially within the therapeutic range and undetectable on placebo treatment, platelet MAO activities were unchanged.

Amitriptyline↗
PubMed1980

Intranasal and oral cocaine kinetics.

Plasma cocaine levels were determined in 7 subjects after intranasal and oral cocaine. Intranasal doses of 0.19, 0.38, 0.75, 1.5, and 2.0 mg/kg were given as a 10% aqueous solution; 0.38 mg/kg was given as crystalline cocaine HCl. Oral cocaine was administered in doses of 2.0 and 3.0 mg/kg. Intranasal cocaine kinetics were described by a 1-compartment open model with 2 consecutive first-order input steps and first-order elimination. Oral cocaine disposition was described by a 1-compartment open model with a lag time followed by a single first-order input phase and first-order elimination. The mean elimination half-life (t 1/2) for cocaine by the intranasal route to 7 subjects was 75 +/- 5 min (mean +/- SE). The mean t 1/2 after oral administration to 4 subjects was 48 +/- 3 min. The relative bioavailability [as determined by the area under the concentration-time curve (AUC)] for the 2.0-mg/kg dose by the intranasal and oral routes was not different. There was a linear increase in AUC with increasing intranasal dose.

Administration, Intranasal↗
PubMed1980

Acute toxicology of ethanol ingestion. Role of the clinical laboratory.

Information from the clinical laboratory can contribute in several ways to the evaluation and management of the acute consequences of alcohol ingestion. If a blood alcohol analysis is not available, measurement of serum osmolality can be helpful. An elevated ethanol level can explain central nervous system depression. Evidence of acute or chronic alcohol use can explain atypical responses to various drugs. Severe acidosis in association with an increased anion gap may suggest ingestion of other toxic volatiles, such as methanol or ethylene glycol. Alcoholic ketoacidosis, also associated with a large anion gap, may occur in the absence of measureable alcohol or positive test for ketones.

Alcoholic Intoxication↗
PubMed1980

Therapeutic monitoring of plasma concentrations of tricyclic antidepressants. Perspective of the clinical laboratory.

Therapeutic ranges for plasma concentrations of the tricyclic antidepressant drugs (TCAs) have not been established with the same degree of certainty as for other commonly monitored drugs, such as antiepileptic and cardioactive agents. Nevertheless, sufficient information is presently available to suggest that measurement of TCAs in appropriate circumstances can be helpful in managing the pharmacotherapy of depressed patients. Presently available techniques for measuring TCAs are time-consuming and costly. Clinical research relevant to understanding the significance of plasma levels, as well as their actual clinical application, would benefit from the development of a reliable, relatively convenient, and inexpensive assay.

Antidepressive Agents, Tricyclic↗
PubMed1979

Serum diazepam concentrations in overdose. Their significance.

Total serum benzodiazepine concentrations were correlated with clinical manifestations in 93 cases of diazepam overdose. Diazepam and nordiazepam were also each separately determined in 101 serum specimens from cases of diazepam overdose, including 27 cases from the aforementioned clinical correlation study. In addition, serum nordiazepam concentrations were measured in five cases of chlorazepate overdose. Concentrations of total benzodiazepine ranged from 1 to 22 microgram/ml. All patients survived with supportive therapy only. Each of the 25 patients who had ingested only diazepam was awake or in grade 0 coma, even when drug concentrations were ten-fold greater than the accepted upper limit of the therapeutic range. None of the patients who had ingested only diazepam needed hospitalization; all were discharged from acute medical care after a period of emergency room observation. The ratios of parent drug to N-desmethyl metabolite (nordiazepam) in those overdose specimens analyzed by gas chromatography averaged 3:1. This high ratio may be useful in differentiating acute overdose from high concentrations resulting from chronic therapy. Although determination of diazepam concentrations aid in establishing that an overdose has occurred, when more than grade I or II coma is present, other drugs or an alternative explanation should be sought, regardless of the drug concentration.

Alcohol Drinking↗
PubMed1979

Improved liquid-chromatographic determination of propranolol in plasma, with fluorescence detection.

We describe an analysis for propranolol in plasma, with use of reversed-phase "high-pressure" liquid chromatography and fluorescence detection. Pronethalol is used as the internal standard. The procedure, which involves extraction into an organic solvent, evaporation, and clean-up by micro-scale back extraction from hexane into an aqueous phase, is specific and sensitive. The detection limit is less than 6 microgram/L (2.3 X 10(-8) mol/L). Within-day and between-day coefficients of variation are 1.8 and 4.4%, respectively. Commonly used drugs, including procainamide, N-acetylprocainamide, and quinidine, do not interfere.

Chromatography, High Pressure Liquid↗
PubMed1978

Oral cocaine: plasma concentrations and central effects.

Cocaine (2.0 milligrams per kilogram) given by the oral route is at least as effective as the same dose given intranasally. Cocaine is not detected in the plasma until 30 minutes after oral administration, but peak plasma concentrations are similar after both routes. The subjective "highs" in man are greater after oral than after intranasal administration.

Administration, Intranasal↗
PubMed1977

Urinary excretion of immunologically reactive metabolite(s) after intranasal administration of cocaine, as followed by enzyme immunoassay.

Using the enzyme immunoassay technique (EMIT), we determined the time course of urinary excretion of benzoylecgonine in 16 surgical patients and three volunteers who received intranasal cocaine. After doses varying from 13 to 130 mg, the test for benzoylecgonine was positive in 1 to 4 h, peaked at about 10 to 12 h, remained positive for 18 to 27 h, and became negative after about 17 h. This information should be considered by drug dependency treatment programs in which the EMIT procedure is used to screen urines for cocaine use.

Administration, Intranasal↗
PubMed1976

Cocaine: plasma concentrations after intranasal application in man.

Cocaine (1.5 milligrams per kilogram) was applied to the nasal mucosa of human subjects. The cocaine persisted in the plasma for 4 to 6 hours and reached peak concentrations of 120 to 474 nanograms per milliliter at 15 to 60 minutes. In that residual cocaine was detectable on the nasal mucosa for 3 hours, continuous absorption secondary to its vasoconstrictive action might explain its persistence in the plasma.

Administration, Intranasal↗
PubMed1975

Ultraviolet spectrophotometry of theophylline in plasma in the presence of barbiturates.

Ultraviolet spectrophotometry is widely used for the analysis of theophylline in blood, for purposes of monitoring therapy, and for pharmacokinetic studies. Phenobarbital, a component of common oral theophylline preparations, interferes with assays now in use. The modification of the method of Schack and Waxler [J. Pharmacol. Exp. Ther. 97, 283 (1949)] presented in this paper eliminates barbiturate interference. After solvent extraction and back extraction into NaOH, the pH of the alkaline solution is adjusted from pH 13 to 10 before spectrophotometric measurement. This shifts the barbiturate absorption maximum from 255 to 240 nm, permitting accurate analysis of theophylline, the spectrum of which is unaffected by the pH change.

Humans↗