Proarrhythmic effects of procainamide and tocainide in a canine infarction model.

A canine model of myocardial infarction (MI) was used to study the type and frequency of ventricular antiarrhythmic and proarrhythmic effects due to procainamide and tocainide and the risk factors associated with development of proarrhythmia. An anterior MI was created by a 2-h occlusion of the left anterior descending artery (LAD) with complete reperfusion. Programmed ventricular stimulation was performed on two occasions after MI, on days 4-6 and on days 8-10, before drug and during antiarrhythmic drug infusion at three dose levels.

Pseudo 2:1 atrioventricular block and T wave alternans in the long QT syndromes.

The extreme prolongation of ventricular action potential duration that occurs in some of the long QT syndromes may result in two forms of alternating activity of the heart: a "pseudo" 2:1 atrioventricular (AV) block and a T wave alternation, both of which are rate dependent. The pseudo 2:1 AV block relates to the extreme prolongation of ventricular refractoriness. The T wave alternation reflects the fact that the rate dependence of action potential duration differs in degree or magnitude in the subendocardial and subepicardial layers of the ventricular wall.

Regional differences in adrenoreceptor status of adipose tissue in adults and prepubertal children.

The relative anatomical distribution of adipose tissue in central (abdominal) vs. peripheral (extremity) depots is highly correlated with the risk of adiposity-related morbidities, such as hypertension, cardiovascular disease, and diabetes mellitus. In adults, comparisons of the functional status of plasma membrane adrenergic receptors indicate that abdominal adipocytes are more responsive to the lipolytic action of beta 1-adrenergic agonists, while gluteal adipocytes are more responsive to the antilipolytic action of alpha 2-adrenergic agonists.

Staying off methadone maintenance.

Methadone maintenance is again receiving attention as an intervention for needle use/sharing among intravenous drug users. A major criticism is that methadone has its own addictive properties; consequently, the client is unable to detoxify and stay off opioids permanently. Study respondents had been off methadone for several years and offered their strategies for success.

Violence in psychiatric wards. Role of the lax milieu.

In recent years there has been a marked increase in interest and publications dealing with violence in psychiatric facilities. There is general agreement that the increase in violent behavior is real despite underreporting prior to the late 1970s. The author proposes that the changes in structure and functioning of psychiatric facilities following the Community Mental Health Act of 1963 may be one of the factors responsible for the increase of violent behavior.

Immediate reproducibility of electrically induced sustained monomorphic ventricular tachycardia before and during antiarrhythmic therapy.

The immediate reproducibility of sustained ventricular tachycardia induction was evaluated prospectively during 106 studies performed in 53 patients with clinical sustained monomorphic ventricular tachycardia. Programmed electrical stimulation was performed twice, using the same protocol during 53 drug-free studies and 53 subsequent studies on antiarrhythmic therapy. Sustained monomorphic ventricular tachycardia was reproduced in 104 (98%) of the 106 studies.

Rate dependence and supernormality in excitability of guinea pig papillary muscle.

It is well known that in most cardiac tissues an increase in rate results in a decrease of excitability and, eventually, conduction block. We used microelectrode techniques to evaluate the rate and time dependence of excitation latency in 27 isolated guinea pig papillary muscles (GPPM). Latency was measured as the interval between the stimulus onset and action potential upstroke.

Contrasting effects of verapamil and procainamide on rate-dependent bundle branch block: pharmacologic evidence for the role of depressed sodium channel responses.

The mechanisms responsible for intermittent bundle branch block are still under debate. The role of the time-dependent behavior of the slow calcium channel has recently been emphasized. To test this hypothesis and ascertain the possible involvement of the fast sodium channel, the effects of the slow calcium channel blocker verapamil and the fast sodium channel blocker procainamide were compared in 10 patients with intermittent bundle branch block.

Effects of systemic growth hormone (GH) administration on regional adipose tissue distribution and metabolism in GH-deficient children.

Chronic administration of exogenous GH to GH-deficient children is associated with a redistribution of adipose tissue from an abdominal (android) to a more peripheral (gynoid) distribution. We studied abdominal and gluteal sc adipose tissue from seven GH-deficient children 1) before beginning and 2) after 3 months of therapy with exogenous GH (0.1 mg/kg, sc, three times per week).

Newer technique of laryngeal reinnervation: superior laryngeal nerve (motor branch) as a driver of the posterior cricoarytenoid muscle.

This report analyzes the experience gained using two different techniques to reinnervate the paralyzed vocal cord. In the neurotization group, the superior laryngeal nerve (SLN) motor branch-cricothyroid muscle pedicle was used to reinnervate the posterior cricoarytenoid muscle. In the direct nerve anastomosis group, the SLN was anastomosed to the abductor branch of the recurrent laryngeal nerve (RLN), and the ansa hypoglossi (AH) to the adductor branch of the RLN.

Identification of major Trypanosoma cruzi antigenic determinants in chronic Chagas' heart disease.

To identify Trypanosoma cruzi target antigens in overt Chagas' heart disease, a parasite lambda gt11 cDNA library was screened with the serum of a patient with a severe chagasic heart involvement (JL). Using a phage dot array immunoassay, 5 highly antigenic clones, JL1, JL5, JL7, JL8, and JL9, were probed with sera from clinically characterized T. cruzi infected subjects.

Metabolic clearance rates of synthetic human growth hormone in children, adult women, and adult men.

The MCR of biosynthetic human GH was studied in 12 prepubertal children, 9 adult women, and 13 adult men. Subjects received a constant infusion of biosynthetic GH, and clearance was calculated by dividing the infusion rates by steady state serum concentrations of GH. We found that adult men have a significantly more rapid MCR of human GH than women (125.

Intravenous refeeding blocks growth hormone (GH)-provoked rises in serum free fatty acids and blunting of somatotroph response to GH-releasing hormone in normal men.

We measured the serum GH responses to GHRH (1 micrograms/kg) in six normal men who had been rendered hyperinsulinemic and hypolipidemic by 10 days of total parenteral nutrition (TPN subjects) with a 25% dextrose-amino acid solution. The men underwent GHRH testing after 3 h of infusion of NaCl or Met-human (h) GH (2 micrograms/kg.h).

Acute inhibition of somatotroph response to human growth hormone-releasing hormone 1-44 occurs following three hours but not one hour of growth hormone infusion.

Our previous studies have demonstrated that a short-term (three hour) infusion of methionyl human growth hormone (met-hGH, 2 micrograms/kg/h) is associated with a rise in serum concentrations of free fatty acids and glycerol, and a blunting of somatotroph response to human growth hormone releasing hormone 1-44 (GRH) in normal volunteers. To gain more information on the time course of this blunting, and to determine whether it could be temporally dissociated from the GH-induced rise in serum concentrations of lipolytic products, the response to GRH (0.3 micrograms/kg) was measured in five normal adult volunteers from hours 1.

Recombinant growth hormone enhances muscle myosin heavy-chain mRNA accumulation and amino acid accrual in humans.

A potentially lethal complication of trauma, malignancy, and infection is a progressive erosion of muscle protein mass that is not readily reversed by nutritional support. Growth hormone is capable of improving total body nitrogen balance, but its role in myofibrillar protein synthesis in humans is unknown. The acute, in situ muscle protein response to an infusion of methionyl human growth hormone was investigated in the limbs of nutritionally depleted subjects during a period of intravenous refeeding.