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Biomedical subjects

D S Thompson

Publications and source records attributed to D S Thompson.

At least 19 recordsLinked to original sources

Pharmacokinetic model for procaine in humans during and following intravenous infusion.

A multicompartment pharmacokinetic model is presented to describe procaine distribution in humans during and following intravenous infusion. The model, based on a general perfusion model, relates individual characteristics such as sex, age, weight, height, infusion rate and duration, and hematocrit to general parameters such as drug metabolism, protein binding, ion-trapping effects, and tissue-plasma distribution coefficients to provide an individualized distribution prediction. Experimentally observed kinetics of blood procaine levels collected during intravenous procaine infusion as an adjunct to surgical anesthesia and blood lidocaine levels obtained from the literature compared very well with the model simulation.

Humans

Reappraisal of intravenous procaine as a short-acting anesthetic adjuvant.

Our data in 74 patients demonstrate that procaine hydrochloride is a safe anesthetic adjuvant in doses of 1 mg/kg/min even when total doses are 5 to 7 g. Blood pressure, heart rate, electrocardiographic variables, and blood gases were not adversely affected. Patients had no nausea or untoward postanesthesia symptoms. Emergence from anesthesia was rapid, within less than 15 minutes in all patients, and most were fully awake before leaving the operating room. In two patients in whom blood levels were studied the drug disappeared within 40 minutes. Procaine is inexpensive, $1.16 for 10 g, and it is not a known liver or kidney toxin. Until studies on cardiovascular dynamics and analgesic effects as in whom a low plasma cholinesterase activity is present or suspected. The clinical appraisal in 56 patients indicates its usefulness in suppressing premature venticular contractions and cough reflexes during endoscopic procedures in the respiratory tract. Procaine can be used to advantage in supplementing general anesthesia in outpatient surgery because of its brief action. For these reasons, the drug merits further study.

Adolescent

Haemodynamic effects of disopyramide in patients after open-heart surgery.

Disopyramide phosphate was administered intravenously in a dose of 1.2 mg/kg body weight over one minute to nine patients after open-heart surgery and coronary artery bypass grafting. The haemodynamic changes were studied during and for 30 minutes after drug administration. Heart rate was unchanged throughout the study. During infusion the only significant changes were an increase in systemic blood pressure and systolic impedance signifying a direct increase in peripheral arterial resistance. Systemic blood pressure remained significantly higher for 10 minutes and systolic impedance for 30 minutes. Immediately after infusion max. dPower/dT, a measure of ventricular contractility, was significantly depressed for 15 minutes. Both cardiac output and aortic flow were significantly depressed for 30 minutes. DPTI/TTI, an estimate of subendocardial supply/demand ratio, showed an insignificant increase throughout the study. This study shows that intravenous disopyramide starts acting within 45 seconds of the start of infusion, directly increases peripheral arterial resistance, has a breif negative inotropic action, and does not reduce subendocardial blood flow.

Adult

Assessment of thrombocytopenic patients for splenectomy.

Platelet survival and splenic sequestration patterns were studied in 32 patients with thrombocytopenia using donor platelets labelled with chromium-51. A shorter mean platelet lifespan was observed in immune thrombocytopenia (ITP) (mean 12 hours) than in hypersplenism (mean 56 hours) or marrow hypoplasia (mean 102 hours). There was no such correlation between diagnosis and splenic sequestration. A biphasic survival curve was seen in nine of 22 patients with ITP. Thirteen patients underwent splenectomy with complete (9) or partial (4) response, but no consistent pattern of results was manifest. It is concluded that in vivo isotope studies are of little value in predicting the benefit of splenectomy in thrombocytopenic patients, although they may demonstrate the mechanism of the thrombocytopenia, in particular the biphasic survival curve revealing separate 'immune' and 'hypersplenic' components of platelet destruction in ITP.

Adolescent

Use of supine pressor test to prevent gestational hypertension in primigravid women.

The supine pressor (roll-over) test was performed on 62 nulliparous patients under 20 years of age at conception. The 28 patients (45%) with positive tests were treated to prevent the development of gestational hypertension. Four of those with a positive test and two of those with a negative test developed gestational hypertension. Compared with a composite of other reported studies of this test in which the patients were not treated, our results indicated a statistically significant reduction in the incidence of gestational hypertension. The supine pressor test appears to be useful clinically in young nulliparous women.

Adult

Preoperative oral antacid therapy for patients requiring emergency surgery.

Preoperative oral antacid therapy has been used effectively to reduce the number of emergency obstetric patients "at risk" of developing acid-aspiration syndrome. Thirty-three nonobstetric adult patients requiring emergency surgery were selected to determine whether the protective effects of antacid therapy could also be derived in this high-risk group. Maalox-treated patients had a mean gastric pH of 6.46 +/- 0.5 and gastric volume 21.5 +/- 3.6 ml, with none at risk, whereas control patients had mean pH of 3.71 +/- 0.43, gastric volume 71.5 +/- 16.5 ml, and 42.1% at risk. This report suggests that preoperative antacid therapy should reduce the incidence of acid aspiration and subsequent morbidity and mortality in patients requiring emergency surgery.

Administration, Oral

Intravenous procaine for general anesthesia in dogs: a new look at an old technic.

New anesthetics have been introduced during the last 25 years which are not without inherent disadvantages. They are expensive, and some produce nephrotoxicity and possibly hepatotoxicity. Although the use of procaine intravenously as an anesthetic has been discarded, probably because of a convulsive effect, it is believed this disadvantage can be controlled by concomitant use of other drugs. Hence procaine, preceded by thiamylal, was administered to dogs to test its anesthetic capability, reversibility, and effects on the cardiovascular and central nervous systems. Blood levels of procaine were measured and correlated with these physiologic responses. Convulsive doses were ten times those producing anesthesia. There were no detrimental effects which would preclude a reevaluation in humans. Intravenous procaine produces definite general anesthesia, and it has the additional advantages of being rapidly hydrolyzed and providing antiarrhythmic effects. It may prove useful in modern anesthesia.

Anesthesia, General

Changes in liver enzyme values after halothane and enflurane for surgical anesthesia.

For over a decade there has been concern about hepatitis related to halothane anesthesia. No dose relationship or other direct cause has ever been established, and jaundice has been found to occur after other anesthetics for surgical operations. Enflurane is a newer halogenated compound with a remarkable record of safety, yet a few cases of hepatitis are reported to be associated with its administration. We have compared effects on the liver of the two anesthetics by testing hepatic serum enzymes and sulfobromophthalein in 12 patients who received halothane and 12 who received enflurane. No significant differences between the two groups were found. Both had similar but minimal elevations of the hepatic serum enzymes and retention of sulfobromophthalein. More than half the patients had enzyme increases over normal levels but reasons for this were not obvious. Since hepatic change may take place in many postoperative patients, it is not surprising to have an occasional one develop hepatitis. The exact cause is unknown and therefore it is impossible to predict the patient who will develop the disease, regardless of the anesthetic.

Adult

Auto-immune neutropenia in an infant.

A case of neutropenia in an infant is described, associated with repeated minor infections which responded to treatment with antibiotics. A granulocyte agglutinin was detected in the serum. Following treatment with prednisolone the neutropenia remitted, the antibody disappeared and the infections ceased. Treatment was discontinued after three months and the child remained well five months later. Reports of similar cases are reviewed and the significance of the antibody discussed.

Agranulocytosis

Measurement of chloroprocaine and procaine in plasma by flame ionization gas-liquid chromatography.

We describe an isothermal gas-liquid chromatographic procedure developed for measuring procaine and chloroprocaine in plasma. The unchanged drug is extracted into toluene from alkalinized plasma, together with an internal standard. The solvent is removed, the residue redissolved in methanol, and aliquots are injected into a 91.5-cm gas-liquid chromatographic column containing 3% OV-210. Sensitivity of detection is in the nanogram range.

Flame Ionization

ATYPICAL SURFACE MAKER CHARACTERISTICS IN A T-cell lymphoma.

A case of T-cell lymphoma with an unusual phenotype is described. The majority of malignant tumour cells did not form E-rosettes, and lacked surface immunoglobulin but reacted with an antiserum to T cells and thymocytes. Localised acid phosphatase and non-specific alpha naphthol acid esterase activities and a prominent, convoluted, nuclear pattern in some neoplastic cells also supported the T cell derivation. The results demonstrate the importance of using a panel of markers for identification of the cellular derivation of some lymphomas.

Acid Phosphatase

Ventricular haemangioendothelioma diagnosed in life.

A case of right ventricular outflow obstruction is described in which the electrocardiogram and chest x-ray film suggested a cardiac tumour. Cardiac catheterisation confirmed outflow obstruction and angiography showed a tumour. At operation a haemangioendothelioma was found.

Child

Measurement of thiamylal and thiopental in plasma by electron capture and flame photometric gas-liquid chromatography.

We describe an isothermal gas-liquid chromatographic procedure developed for measuring thiamylal and thiopental in plasma. The unchanged drug is extracted into ethyl acetate from acidified plasma, together with an internal standard. The solvent is removed, the residue methylated, aliquots, diluted with benzene, are injected into a 183-cm gas-liquid chromatographic column containing 3% OV-17. Sensitivity of detection is in the nanogram to picogram range.

Chromatography, Gas

Repeat aborters.

In an attempt to learn more about the phenomenon of repeat abortions, 116 women seeking a repeat abortion were compared in various ways with three groups of women not seeking a repeat abortion but otherwise similar. From this study it is apparent that postabortion women become, over time, less persistent users of contraception than sexually active nonpregnant women. However, they are more likely to use contraception continually than are women seeking a first abortion. The abortion experience, with or without concurrent family-planning guidance, does not create universally sufficient long-lasting motivation to use of contraception. Some other factors which might contribute to this motivation are presented.

Abortion Applicants

A comparison of the incidence of cardiac arrhythmia during two methods of anaesthesia for dental extractions.

One hundred premedicated inpatients undergoing wisdom tooth extraction were divided into two groups of 50. Group A was anesthetized by a technique based on droperidol and phenoperidine, whilst group B was anaesthetized with halothane. The e.c.g. in both groups demonstrated a similar overall incidence of cardiac arrhythmia, but analysis revealed a significantly higher incidence of ventricular arrhythmia in group B. The heart rate was significantly less in group A.

Adolescent