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Biomedical subjects

J J Lynch

Publications and source records attributed to J J Lynch.

At least 163 records · Page 9Linked to original sources
PubMed1983

Intracellular localization of the calcium antagonist propyl-methylenedioxyindene in cardiac tissue.

Propyl-methylenedioxyindene (pr-MDI) is a coronary dilating and antiarrhythmic calcium antagonist with an intracellular site of action in cardiac tissue, probably involving inhibition of calcium mobilization from the sarcoplasmic reticulum and preservation of mitochondrial structural and functional integrity. Perfusion of isolated guinea-pig hearts with [14C]pr-MDI resulted in negative inotropism, with the time-course of this effect paralleling the uptake of the drug in the whole heart and the time-course of its accumulation in atrial and ventricular tissue. Tissue-to-medium ratios of pr-MDI for both atria and ventricles were high, and washout of the drug from the heart was biexponential. Pr-MDI associated poorly with a cardiac subcellular fraction exhibiting the highest specific activity of sarcolemmal marker enzyme. The highest specific activity of pr-MDI occurred in the cardiac mitochondrial fraction and in a fraction enriched with a putative sarcoplasmic reticular marker, and the accumulation of drug in these fractions was temporally correlated with its negative inotropic action. The results support an intracellular site of action of pr-MDI in cardiac tissue.

Animals↗
PubMed1983

Social interaction and blood pressure. Influence of animal companions.

The effect of the presence of a friendly animal on children's blood pressures and heart rates while resting and their cardiovascular responses to verbalization were examined. The presence of the dog resulted in lower blood pressures both while the children (N = 38) were resting and while they were reading. The effect of the presence of the dog was greater when the dog was present initially than when it was introduced in the second half of the experiment. We speculate that the animal causes the children to modify their perceptions of the experimental situation and the experimenter by making both less threatening and more friendly. This study provides insight into the use of pets as adjuncts in psychotherapy.

Adolescent↗
PubMed1982

The effect of status on blood pressure during verbal communication.

Blood pressures and heart rates of 40 subjects were recorded at 1-min intervals over 35 min during which subjects engaged in a variety of verbal activities with either a high-status or an equal-status experimenter. All subjects showed statistically significant increases in blood pressure and heart rate when speaking compared to when quiet. Blood pressure increases during speaking of the 20 subjects exposed to a high-status experimenter were significantly greater than those of subjects exposed to an equal-status experimenter. While the blood pressure increase was related partly to the act of speaking, the amount of increase was also related to the social distance between experimenter and subject. The results are discussed relative to behavioral interventions for the treatment of hypertension.

Adult↗
PubMed1982

Interpersonal aspects of blood pressure control.

Recent observations of large, consistent increases in blood pressure during human communication prompted a reassessment of the role of interpersonal factors in the behavioral control of hypertension. It was noted that the conceptual framework around which earlier behavioral studies have been carried out, as well as in the physical methods of pressure determination themselves, have contributed to a general lack of information about the role of interpersonal interactions in hypertension. An awareness of the relationship between speaking and pressure elevations has led to the development of a new conceptual approach to understanding the etiology and treatment of hypertension. Using techniques developed out of transactional psychophysiology, hypertensive patients have been able to observe the importance of interpersonal communications in the regulation of their own blood pressure. Evidence from the clinical use of such information suggests that a new way can be developed to help patients lower their blood pressure.

Behavior Therapy↗
PubMed1982

The effects of normal and rapid speech on blood pressure.

The effects of two rates of speech on blood pressure and heart rate were measured in 30 normotensive individuals. Verbalization was linked to rapid and significant rises in blood pressure. Faster rates of speaking were associated with greater increases in blood pressure. These findings are discussed in light of earlier research on the blood pressure communication response and are evaluated in the context of the speech pattern characteristics of the Type A (coronary-prone) individual. Clinical applications of this research for hypertensive and Type A individuals are discussed.

Adult↗
PubMed1982

Absence of blocking effects on cardiac slow calcium channels by the intracellular calcium antagonist 2-n-propyl-3-dimethylamino-5,6-methylenedioxyindene.

Extensive pharmacological evidence supports the contention that 2-n-propyl-3-dimethylamino-5,6-methylenedioxyindene hydrochloride (pr-MDI) is a calcium antagonist with a predominantly intracellular site of action. On the other hand, electro-physiological evidence points to a possible membrane slow inward calcium channel blocking property of this agent. To gain further insight as to the site of action of pr-MDI, the interactions between the negative inotropic action of this agent and the positive inotropic actions of excess extracellular calcium (which directly penetrates the myocardial cells through the slow calcium channels), isoproterenol (which indirectly augments calcium influx through the slow calcium channels), and ouabain (which enhances calcium influx through membrane calcium entry routes distinct from the slow calcium channels) were investigated in the isolated, electrically drive guinea pig left atrium. Although excess extracellular calcium, isoproterenol, and ouabain reversed the negative inotropic effect of pr-MDI, an analysis of the concentration-response relationships to all three positive inotropic agents in the presence and the absence of pr-MDI demonstrated that this agent did not significantly inhibit the contractile effects of calcium, isoproterenol, or ouabain, at pr-MDI concentrations which exhibit intrinsic negative inotropic effects. It is concluded that pr-MDI does not block the membrane slow inward calcium channel nor other presumptive membrane routes of calcium entry into myocardial cells at concentrations of 10(-4) M or less. At very high concentrations (3 X 10(-4) M) some inhibition of slow channel calcium influx may occur.

Animals↗
PubMed1982

Effects of tertiary and quaternary derivatives of aminomethylenedioxyindenes on some experimental arrhythmias.

The 2-n-propyl- and 2-n-butyl-3-dimethylamino-5,6-methylenedioxyindene hydrochlorides are intracellular calcium antagonists with coronary dilating and antiarrhythmic effects against ouabain- and calcium-induced arrhythmias. In the present study, pretreatment with these tertiary methylenedioxyindenes afforded significant protection against the calcium-dependent arrhythmias induced by chloroform in mice. On the other hand, their antiarrhythmic activity against aconitine- and methacholine-induced arrhythmias in rats (in which calcium does not play a primary etiological role) was suggestive but not impressive. The quaternary derivative, 2-n-butyl-5,6-methylenedioxy-3-trimethylammonium iodide, which was synthesized with the expectation of being devoid of antiarrhythmic activity owing to its exclusion from the intracellular compartment, unexpectedly demonstrated greater antiarrhythmic potency than the tertiary analogues against calcium-induced arrhythmias in rats and chloroform-induced arrhythmias in mice. Like the tertiary methylenedioxyindenes, the protective activity of the quaternary analogue against arrhythmias induced by aconitine or by methacholine in rats was suggestive but not impressive. Because of the relative inactivity of the quaternary methylenedioxyindene in vitro, it is proposed that its in vivo activity may be due either to metabolic activation or to concentration in cardiac tissue in sufficient quantity to allow diffusion into cardiac cells down a concentration gradient or to alter membrane electrophysiological properties to the extent of exerting antiarrhythmic activity.

Aconitine↗
PubMed1982

Effects of tertiary and quaternary derivatives of aminomethylenedioxyindenes on the mechanical and electrical activity of isolated guinea pig atria.

The 2-n-propyl- and 2-n-butyl-3-dimethylamino-5,6-methylenedioxyindenes (pr-MDI and bu-MDI, respectively) have been characterized as calcium antagonists with coronary dilating and antiarrhythmic properties. The quaternary 2-n-butyl-3-trimethylamino MDI (Q-bu-MDI) has been demonstrated to possess very potent antiarrhythmic activity in several model systems. In this investigation, the effects of pr-MDI, bu-MDI, and Q-bu-MDI on the mechanical and electrical behavior of isolated guinea pig atria were investigated. The tertiary pr- and bu-MDIs caused marked, concentration-dependent decreases in contractile force of stimulated left atria, while the Q-bu-MDI caused only a slight peak reduction in contractile force which was partially reversed at high concentrations. At a concentration of 3 x 10(-4) M, the pr- and bu-MDIs significantly depressed the frequency-force profile of stimulated left atria, and significantly decreased membrane excitability (as reflected by a significant increase in threshold voltage), while the Q-bu-MDI did not significantly alter either parameter. Spontaneous right atrial rate was only slightly depressed by the three MDI analogues at concentrations of 3 x 10(-5) M or less. At higher concentrations, the tertiary pr- and bu-MDIs were much more potent than the quaternary analogue in reducing atrial rate. The results indicate that Q-bu-MDI, the most potent antiarrhythmic analogue in the MDI series, exhibits significantly lesser deleterious effects on cardiac function than the tertiary MDIs.

Animals↗
PubMed1982

Automated blood pressure recording: the phenomenon of blood pressure elevations during speech.

The recent development of automatic non-invasive blood pressure devices has allowed the rapid and repeated assessment of both the blood pressure and pulse rate in the clinical setting. The development of this technology has allowed us to observe a striking relationship between human communication and blood pressure. Talking produces rapid increases in their systolic, diastolic and mean arterial pressures as well as pulse rate in both normotensive and hypertensive subjects. This phenomenon has been obscured by the conventional assessment techniques of blood pressure measurement. Ignoring the pattern of verbal communication during the assessment of blood pressure can result in marked differences in recorded blood pressure and its interpretation.

Adult↗
PubMed1982

Blood pressure changes while talking.

Using a noninvasive automatic device to rapidly and repeatedly measure blood pressure, a striking relationship was found between talking and an increase in blood pressure and heart rate. This finding was demonstrated in a variety of experimental settings (the laboratory, medical clinic, classroom and home) in both children and adults and in both normotensive and hypertensive individuals. A significant positive correlation was also observed between the level of resting pressure and the magnitude of increase in pressure while talking. These findings point toward an important link between human communication and blood pressure control that has previously been overlooked. They also suggest a new conceptual approach to the understanding and treatment of hypertension.

Adolescent↗
PubMed1981

The effects of talking on the blood pressure of hypertensive and normotensive individuals.

The use of a recently developed noninvasive automated blood-pressure device has revealed a striking relationship between human communication and elevations in blood pressure in both normotensive and hypertensive individuals. Individuals with higher resting baseline pressures tended to show greater increases during talking than did those with lower pressures. In some hypertensive individuals increases blood pressure greater than 25-40% occurred within 30 sec after the initiation of human speech. Links between difficulties surrounding human communication and elevations in blood pressure are discussed.

Adult↗
PubMed1981

Evidence for messenger ribonucleic acid of an ammonium-inducible glutamate dehydrogenase and synthesis, covalent modification, and degradation of enzyme subunits in uninduced Chlorella sorokiniana cells.

The cells of Chlorella sorokiniana cultured in nitrate medium contain no detectable catalytic activity of an ammonium-inducible nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH). However, several lines of experimental evidence indicated that the NADP-GDH messenger ribonucleic acid was present at high levels and was being translated in uninduced cells. First, binding studies with 125I-labeled anti-NADP-GDH immunoglobulin G and total polysomes isolated from uninduced and induced cells showed that NADP-GDH subunits were being synthesized on polysomes from both types of cells. Second, when polyadenylic acid-containing ribonucleic acid was extracted from polysomes from uninduced and induced cells and placed into a messenger ribonucleic acid-dependent in vitro translation system, NADP-GDH subunits were synthesized from the ribonucleic acid from both sources. Third, when ammonia was added to uninduced cells, NADP-GDH antigen accumulated without an apparent induction lag. Fourth, by use of a specific immunoprecipitation procedure coupled to pulse-chase studies with [35S]sulfate, it was shown that the NADP-GDH subunits are rapidly synthesized, covalently modified, and then degraded in uninduced cells.

Ammonium Sulfate↗
PubMed1980

Human speech and blood pressure.

The recent development of a noninvasive automated blood pressure device has revealed a strong relationship between human conversation and blood pressure. Conventional techniques of pressure measurement such as the stethoscope and manometer, which require silence during the measurement, tended to obscure this important relationship. Findings from this study indicate that interpersonal communications surrounding the measurement of blood pressure can rapidly alter systolic and diastolic pressures. In certain situations, changes greater than 20 per cent in systolic and diastolic blood pressure and heart rate can occur within 30 seconds after the initiation of human speech. Such variance can be of critical significance in making clinical judgments concerning hypertension. These findings are discussed in the context of recent nonpharmacological treatment approaches being developed to help control hypertension.

Adult↗
PubMed1980

Typhoid fever. An unusual radiographic presentation with appendicitis.

Previous reports have well documented the radiographic appearance of typhoid fever as seen on barium meal antegrade studies. A case is presented whereby barium enema, with small bowel reflux, presents similar radiographic findings. Because the enema is more likely to be employed in emergency situations to exclude appendicitis prior to definitive diagnosis, knowledge of such an appearance of typhoid fever is important.

Appendicitis↗
PubMed1980

A study of leadership and satisfaction variables in medical record departments of general hospitals.

Twenty-nine hospital medical record departments participated in a study to measure specific leadership and satisfaction variables. The variables studied were leader consideration, leader initiating structure, satisfaction with job, and satisfaction with department head. Medical record directors were characterized by a moderate degree of initiating structure and a moderately high degree of consideration. Medical record department employees expressed low levels of satisfaction. The results are discussed and recommendations made.

Costs and Cost Analysis↗