The pharmacokinetics and pharmacodynamics of newer inotropic agents

In the past few years an intense effort has been directed toward the development of new inotropic agents for the treatment of chronic cardiac failure. Traditionally, therapy of this disease has included treatment with digitalis glycosides, diuretics, sodium restriction and vasodilators. While digitalis has proven to be an effective inotropic agent, it possesses a low therapeutic index and many patients remain symptomatic or 'refractory' despite its inotropic effects. This review focuses on the pharmacokinetics and pharmacodynamics of newer inotropic agents that have been developed or which are currently undergoing investigation. Amrinone and milrinone are two bipyridine derivatives which have been shown to be effective in the short term treatment of cardiac failure. Milrinone is currently being evaluated for its long term efficacy. The mechanism of action of amrinone and milrinone appears to be unrelated to the cardiac glycosides and sympathomimetic agents, and they are rapidly and well absorbed following oral administration. The bioavailability of milrinone appears to be somewhat reduced in patients with chronic cardiac failure. The distribution of these drugs to extravascular tissues is very rapid; the volume of distribution suggests that they are not extensively bound to tissues. While the volume of distribution of amrinone appears to be unaffected by the presence of heart failure, that of milrinone appears to be somewhat enhanced. The major route of elimination of both drugs appears to be excretion into urine as unchanged drug. A substantial fraction of the amrinone dose, however, undergoes hepatic metabolism to many metabolites, including an N-acetyl derivative. Clearance of amrinone and milrinone is dramatically reduced in patients with chronic cardiac failure compared with normal volunteers, resulting in proportionate increases in the serum half-lives of these drugs. Studies examining the acute and chronic disposition of these agents in cardiac failure patients have not demonstrated changes in their pharmacokinetics secondary to improvements in cardiocirculatory function. Both drugs show strong correlations between mean improvements in haemodynamics and drug serum concentrations, although considerable intrapatient variability may exist. It is currently unclear as to whether the site for the pharmacological action of amrinone is pharmacokinetically distinguishable from plasma. Enoximone and its sulphoxide metabolite, piroximone, are two compounds currently undergoing investigation for the treatment of chronic cardiac failure.(ABSTRACT TRUNCATED AT 400 WORDS)

Mood, cognition and cortisol: their temporal relationships during recovery from depressive illness

Single-case methodology, using cross-lagged panel correlations, was applied to study the order of change in mood, cognition and cortisol concentration in eight in-patients with a diagnosis of major, endogenous depression. Daily measures included: two visual analogue scales measuring depressed mood and general feeling of unwellness; cortisol concentration in saliva (sampled four times a day) and in 24-h urine; two cognitive scales, the Automatic Thoughts Questionnaire and the Cognitive Style Test. The results relating to the temporal relationship between biological and psychological data were ambiguous as the pattern of change was inconsistent among individuals. Group data indicated that changes in feeling unwell preceded changes in early evening salivary cortisol and changes in negative automatic thoughts preceded changes in day and early evening salivary cortisol. Psychological variables and cortisol concentrations were generally negatively correlated within individuals indicating that over the short recovery period improving mood and cognition were associated with increasing levels of cortisol. A more consistent pattern of precedence of change was obtained for mood and cognition: negative cognitive style predicted changes in both mood measures and feeling unwell predicted changes in negative automatic thoughts.

Dihydropyridazinone cardiotonics: synthesis and inotropic activity of 5'-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)spiro[cycloalkane- 1,3'-[3H]indol]-2'(1'H)-ones

In the 1,3-dihydro-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)-2H-indol-2-one series of cardiotonics, we found that a spirocycloalkyl ring may be annealed to the 3-position of the indolone moiety while retaining inotropic activity. An inverse relationship was found between spirocyloalkyl ring size and inotropic potency. ED50 values of the spirocyclopropane 10, spirocyclobutane 12, and spirocyclopentane 13 were 2.7, 35, and 133 micrograms/kg, respectively, following iv administration to pentobarbital-anesthetized dogs. The most potent compound prepared was 11 (5'-(1,4,5,6-tetrahydro-4-methyl-6-oxo-3-pyridazinyl)spiro[cyclopropane- 1,3'-[3H]indol]-2'(1'H)-one), the 4-methyl analogue of 10. This compound had an iv ED50 of 1.5 microgram/kg. Oral activity was evaluated by administering 50 micrograms/kg of 10 to conscious, chronically instrumented dogs. A 39% increase in LV dP/dt60 was observed, and an inotropic effect was demonstrable in excess of 7 h. Thus, the spirocyclic dihydropyridazinone inotropes are potent, long-acting, orally effective cardiotonics. Compound 11 was a potent inhibitor (IC50 = 13 nM) of cAMP phosphodiesterase derived from canine cardiac sarcoplasmic reticulum (SR-PDE). Importantly, -log IC50 values for inhibition of SR-PDE for this entire series of compounds were highly correlated (r = 0.949, p less than 0.02) with their inotropic -log ED50 values, supporting the hypothesis that inhibition of this enzyme contributes to the mechanism of action of the spirocyclic dihydropyridazinones.

Pharmacokinetics and hemodynamics of amrinone in patients with chronic cardiac failure of diverse etiology

The pharmacokinetics of amrinone and its relationship to ventricular function were assessed in 15 patients with chronic cardiac failure following the administration of a single 100 mg oral dose. Patients examined had Class II (1 patient), Class III (13 patients) and Class IV (1 patient) heart failure as characterized by the New York Heart Association classification. Blood samples were obtained following amrinone administration at selected times for 8 hours following the dose. Cardiac output was assessed serially for 5 hours following amrinone dosing. Mean (SD) peak plasma concentrations of amrinone (2.1 (1.1) mcg/ml) were obtained 0.5 to 2 hours after drug administration. The mean (SD) apparent oral clearance, apparent volume of distribution at steady state and half-life of amrinone were 0.23 (0.13) L/hr/kg, 1.2 (0.4) L/kg, and 4.8 (3.0) hr. Peak increases in cardiac index averaged 50% of baseline values and improvement was maintained at least 5 hours following amrinone dosing when compared to baseline cardiac index (p less than 0.05). Examination of the relationship between cardiac index corrected for baseline and amrinone plasma concentrations within individuals yielded strong and highly significant relationships (r greater than 0.90; p less than 0.025) in five patients, while in the remaining patients, either no relationship existed or insufficient data was available for analysis. When the data from all patients were pooled, a modest though significant relationship (r = 0.67; p less than 0.01) existed between cardiac index corrected for baseline and the post-absorptive, post-distributive amrinone plasma concentration. No difference in response to amrinone as a function of failure etiology or functional aerobic capacity was evident. Evaluation of the relationships between the mean improvement in cardiac index versus amrinone plasma concentration, as well as the time courses of these parameters indicate that the site of action of amrinone may be pharmacokinetically distinguishable from plasma and the tissues in instantaneous equilibrium with plasma.

Pharmacology of LY195115, a potent, orally active cardiotonic with a long duration of action

Compound LY195115 is a novel cardiotonic with both inotropic and vasodilator activities. In cat papillary muscles, LY195115 increased contractility in a concentration-dependent manner; its actions were not blocked by either prazosin or propranolol. An intravenous dose of 7.0 micrograms/kg LY195115 resulted in a 50% increase in contractility in anesthetized dogs; comparable inotropic responses were observed in anesthetized cats receiving 10 micrograms/kg i.v. These doses of LY195115 increased heart rates of both dogs and cats by less than 10%. Oral administration of 25 micrograms/kg to conscious dogs was associated with a selective inotropic response that was maximal at 3 h and maintained in excess of 23 h. This effect was not accompanied by gross behavioral changes or emesis. The hemodynamic profile of LY195115 was evaluated in anesthetized beagle dogs. A 60-min infusion of 1.0 microgram/kg/min LY195115 followed by a 5-min infusion of 10 micrograms/kg/min resulted in dose-dependent increases in contractility (LV dP/dt60) and heart rate; doses that increased LV dP/dt60 by 50% increased heart rate by less than 10%. Doses of greater than 5.0 micrograms/kg decreased left ventricular end-diastolic pressure and systemic vascular resistance; mean arterial blood pressure and cardiac output were unchanged. Estimated myocardial oxygen consumption (heart rate times either systolic or mean arterial blood pressure) was not altered by doses as high as 110 micrograms/kg. This balance of inotropic/vasodilator activities may provide a means of improving cardiac function while maintaining myocardial oxygen supply/demand.

Severe pulmonary hypertension and arterial adventitial changes in newborn calves at 4,300 m

Some human newborns have a syndrome characterized by irreversible pulmonary hypertension and severe hypoxemia and by medial hypertrophy and adventitial thickening of pulmonary arteries. We considered that newborn calves made severely hypoxic might reproduce features of the human disease. When 2-day-old calves were placed at 4,300 m simulated altitude, pulmonary arterial pressure was increased and could be reversed by 100% O2. However, after 2 wk at 4,300 m, pulmonary arterial pressures were suprasystemic and there was right-to-left shunting probably through the foramen ovale and a patent but restrictive ductus arteriosus. Suprasystemic pulmonary pressure and hypoxemia persisted with 100% O2 breathing. Morphometrical examination of the lung arteries showed a markedly thickened adventitia with cellular proliferation and collagen and elastin deposition. There was increased medial thickness and distal muscularization of the pulmonary arteries associated with decreased luminal diameter. The rapid development of severe pulmonary hypertension and poor responsiveness to O2 was associated with increased arterial wall thickness, particularly involving the adventitia. Thus the pulmonary arterial circulation in these calves, which were placed at high altitude for 2 wk, exhibited features resembling persistent pulmonary hypertension in newborn infants.

The use of the Diagnostic Interview Schedule in drug-dependent patients

In an attempt to diagnose other psychiatric disorders in substance abusers, some clinicians and investigators have utilized the NIMH Diagnostic Interview Schedule (DIS). This study assessed the validity of the DIS in a drug-dependent population by comparing DIS diagnoses with clinical diagnoses in 124 hospitalized drug abusers. Every attempt was made to establish the validity of the clinical diagnoses; these represented a consensus of two independent psychiatrists, based on repeated clinical interviews, observation of ward behavior, and information obtained from relatives regarding patient and family history. Concordance between clinical and DIS diagnoses (represented by the kappa statistic and percent agreement) was only moderate for DSM-III Axis I disorders other than substance abuse. In addition, the DIS diagnosed alcoholism less often and antisocial personality disorder more often than the clinicians. Factors contributing to the discrepancy between clinical and DIS diagnoses in this specific population include (a) drug abuse effects, whereby distinguishing between drug effects and primary psychiatric symptoms may be difficult; and (b) the effect of the treatment process itself, whereby patients are encouraged to rethink the role drugs have played in causing some of their difficulties. Patients' reports of the chronology of their symptoms may thus change according to what they have learned in treatment. The authors conclude that the DIS, like any single diagnostic interview, may have limited utility early in the treatment of drug-dependent patients, since their recollection of their previous symptoms may change dramatically as a result of treatment efforts.

Clinical spectrum of Kawasaki disease in infants younger than 6 months of age

We report an unselected series of eight patients younger than 6 months of age with Kawasaki disease evaluated between January 1982 and May 1984. The incidence of coronary artery aneurysms (six patients) and the mortality (two patients) were unusually high in this small series. Because of the confusing clinical presentation in three patients, diagnosis was delayed until pathologic or echocardiographic evidence of coronary vasculitis or aneurysm was discovered. The currently accepted clinical criteria for Kawasaki disease may not always identify patients with the pathologic findings of the syndrome who are younger than 6 months of age. The diagnosis of Kawasaki disease and echocardiographic evaluation of the coronary arteries should be considered in young infants with prolonged fever of unknown origin.

Dihydropyridazinone cardiotonics: the discovery and inotropic activity of 1,3-dihydro-3,3-dimethyl-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)-2H -indol-2- one

We discovered that 6 (N-[4-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)phenyl]acetamide) is a potent positive inotrope in dogs, and we have prepared several lactam analogues of this agent. These included 16 (1,3-dihydro-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)-2H-indol-2-one), 32 (the analogous quinolin-2-one), and 37 (the analogous benzazepin-2-one). The inotropic ED50's of these compounds were 24, 3.3, and 5.2 micrograms/kg, respectively, after iv administration to pentobarbital-anesthetized dogs. Compound 20 (LY195115, 1,3-dihydro-3,3-dimethyl-5-(1,4,5,6-tetrahydro-6-oxo-3-pyridazinyl)-2H-i ndol-2- one), the geminal dimethyl analogue of 16, was 3.5-fold more potent than 16 when administered iv (ED50 = 6.8 micrograms/kg). However, the most profound effect of the geminal alkyl substitution was on oral activity. The approximate ED50's of 20 and 16 after oral administration to conscious dogs were 25 and 400 micrograms/kg, respectively. The increase in contractility produced by 25 micrograms/kg of 20 was maximally sustained in excess of 8 h. Thus, 20 is one of the most potent and long-acting oral inotropes described to date.

The effects of alfentanil and selected narcotic analgesics on the rate of action potential discharge of medullary respiratory neurones in anaesthetized rats

The effects of intravenous injections of alfentanil, fentanyl, phenoperidine or morphine on respiratory and peak inspiratory air flow rate, the diaphragm electromyogram (EMG), the activity recorded extracellularly from respiratory neurones located in the ventral respiratory group and the cardiovascular system were examined in anaesthetized rats. Alfentanil produced dose-dependent changes in peripheral and central respiratory parameters, which were prevented by naloxone pretreatment. Minimal effects were produced on the cardiovascular system. The bradypnoea was principally due to a prolongation of the inspiratory phase and was accompanied by a comparable decrease in the peak inspiratory air flow rate. Alfentanil prolonged the discharge duration of inspiratory neurones such that it still maintained a strict phase correlation with the diaphragm EMG, but changes in firing frequency were inconsistent and negligible. The action on expiratory neuronal discharge was analogous to that on inspiratory neuronal discharge but delayed in onset. Hypotension produced by morphine limited the dose used but the respiratory responses to morphine and other selected narcotic analgesics were otherwise similar to that of alfentanil, differing mainly in time-course and magnitude. From the respiratory parameters assessed, the order of duration of effect was morphine greater than phenoperidine greater than fentanyl greater than alfentanil and the relative potencies were 0.1, 0.5, 2.5 and 1 respectively. The selective prolongation of inspiration and the immediate action on inspiratory neurones suggests that systemically administered narcotic analgesics may alter the mechanisms within the central respiratory rhythm generator which determine the cessation of inspiration.

Effects of exposure of DNA to methyl mercury on its activity as a template-primer for DNA polymerases

A previous publication [Frenkel, Cain, and Chao, Biochem. Biophys. Res. Commun. 127, 849-856 (1985)] described the observation that double-stranded DNA which was briefly exposed to methyl mercury (MeHg) and purified to remove free methyl mercury was transcribed at a higher rate by RNA polymerase II from wheat germ. The specificity of this phenomenon has now been investigated by examining the activity of this MeHg-exposed DNA as a template-primer for DNA polymerases. DNA synthesis by the bacteriophage T4-induced DNA polymerase was higher with the MeHg-exposed DNA as a template-primer than with control DNA. In contrast, the rate of DNA synthesis by E. coli DNA polymerase I was lower with the MeHg-exposed DNA as template-primer. With both enzymes (as well as with RNA polymerase II), after denaturation of the MeHg-exposed and control DNAs the differences in template activity were either eliminated or markedly reduced. The enzymes are thus able to detect a MeHg-induced alteration in DNA. In contrast, circular dichroism, a physical method that is sensitive to conformational changes in DNA, did not detect any difference between the MeHg-exposed and control DNAs.

Bipyridine cardiotonics: the three-dimensional structures of amrinone and milrinone

The cardiotonic drug milrinone (1,6-dihydro-2-methyl-6-oxo-[3,4'-bipyridine]-5-carbonitrile) is superior to its analogue amrinone (5-amino-[3,4'-bipyridin]-6(1H)-one) by virtue of its greater potency and reduced side effect profile. We confirmed initial reports on the potencies of milrinone and amrinone and found that after intravenous administration to phenobarbital anesthetized dogs, the drugs had cumulative inotropic ED50's of 37 and 1891 micrograms/kg, respectively; relative effects on heart rate and blood pressure were comparable. There are two structural differences between amrinone and milrinone: (1) milrinone has a pyridone 2-methyl substituent and (2) the pyridone 5-amino substituent of amrinone is replaced with a nitrile in milrinone. We confirmed structure-activity studies that indicated that the 2-methyl substituent appears to be primarily responsible for the dramatic difference in the potencies of amrinone and milrinone. A plausible explanation for the effect of the methyl substituent is an altered molecular topology resulting from its steric interaction with the 3',5'-hydrogen atoms. Consequently, we probed the three-dimensional structures of these two compounds by X-ray crystallography. The dihedral angle between the planes formed by the two aromatic rings of amrinone was 1.3 degrees. In marked contrast, the corresponding angle for milrinone was 52.2 degrees. Moreover, 1H NMR studies revealed conformational differences in solution. Whereas the 2-methyl substituent undoubtedly produces some electronic and hydrophobic perturbations in the bipyridine cardiotonic series, the most significant effect, from a global viewpoint, is the altered molecular topology.

Effect of insulin and oral glutathione on glutathione levels and superoxide dismutase activities in organs of rats with streptozocin-induced diabetes

The effect of insulin or glutathione treatment on glutathione content of liver and jejunal mucosa and on superoxide dismutase (SOD) activity of liver, kidney, and erythrocytes was investigated in pair-fed animals with streptozocin (STZ)-induced diabetes. Diabetes lowered hepatic glutathione concentration, but glutathione concentration of the jejunal mucosa was not affected. Insulin, but not oral glutathione, restored hepatic glutathione concentration to normal levels. Diabetes depressed activity of the cytosolic form of SOD in liver, kidney, and erythrocyte. Treatment of diabetic rats with oral glutathione or intramuscular insulin increased cytosolic SOD activity of renal cortex and liver (but not erythrocytes) to control levels. These results suggest a link between glutathione metabolism and cytosolic SOD activity in diabetes.

Milrinone in the treatment of chronic cardiac failure: a controlled trial

This study examines the acute hemodynamic response to intravenous and oral milrinone in 12 patients with moderate to moderately severe heart failure. The patients received milrinone or placebo at random in an 8-week double-blind trial. Dosing level and schedule were determined by the hemodynamic results. Acute and chronic plasma samples for milrinone concentration were drawn from patients throughout the study. Milrinone was administered intravenously in successive doses of 25, 50, and 75 micrograms/kg. This resulted in a 16.5%, 12.5%, and 28.4% peak increase in cardiac index, with a concomitant 24%, 29%, and 38% decrease in pulmonary capillary wedge pressure. There were no significant relationships between any of the mean maximal hemodynamic values and milrinone plasma concentration. Six patients received milrinone and six patients received placebo; only five patients completed the blinded phase. There was no significant difference between the groups in exercise capacity, but the conditions of five of the six patients who received placebo deteriorated. In two of the patients who received milrinone the aerobic capacity improved greater than 2 cc/min/kg over baseline, and an additional two patients reported a marked subjective improvement. The results of this study indicate that oral milrinone in the management of patients with chronic cardiac failure would justify larger controlled studies.

Structure-activity relationships of arylimidazopyridine cardiotonics: discovery and inotropic activity of 2-[2-methoxy-4-(methylsulfinyl)phenyl]-1H-imidazo[4,5-c]pyridine

Recently several noncatecholamine, nonglycoside cardiotonic drugs have been discovered that possess both inotropic and vasodilator activities in experimental animals and man. Prototypical compounds include amrinone, sulmazole, and fenoximone. We investigated the structural requirements necessary for optimal inotropic activity in a series of molecules containing a heterocyclic ring fused to 2-phenylimidazole and discovered that 2-phenylimidazo[4,5-c]pyridines were generally 5-10-fold more potent than analogous 2-phenylimidazo[4,5-b]pyridines (e.g., sulmazole) or 8-phenylpurines. Furthermore, all imidazo[4,5-c]pyridine analogues we tested were orally active; in contrast, only one of the imidazo[4,5-b]pyridine derivatives, sulmazole, was significantly active. One of several highly active compounds in the [4,5-c] series was 50 (LY175326, 2-[2-methoxy-4-(methylsulfinyl)phenyl]-1H-imidazo[4,5-c]pyridine hydrochloride). The structure-activity relationship of this series is presented and compared to that of the imidazo[4,5-b]pyridine and purine series.

Antidepressant treatment of children: clinical relapse is unrelated to tricyclic plasma concentrations

Plasma concentrations of imipramine and amitriptyline and their desmethylated metabolites were measured in 20 children being treated for major depressive illness 2 wk. and 5 to 10 wk. after achieving drug dosages of 2.25 mg/kg body weight. At 2 wk. all children had exhibited clinical improvement, but by 10 wk. 4 of the 10 children treated with imipramine and 5 of the 10 children treated with amitriptyline had experienced clinical relapse of depressive symptoms. Tricyclic antidepressant plasma concentrations and ratios were comparable in the subgroups of children who maintained their clinical improvement and those who relapsed. There was no evidence of a systematic decline in plasma tricyclic antidepressant concentrations in those children who relapsed.

Pharmacology of LY175326: a potent cardiotonic agent with vasodilator activities

Compound LY175326 is one of a series of novel cardiovascular agents with both inotropic and vasodilator activities. In cat papillary muscles, LY175326 increased contractility in a concentration-dependent manner; these actions were not blocked by prazosin, propranolol or cimetidine. Inotropic responses were observed in unpaced, perfused guinea-pig hearts and these effects were associated with modest increases in heart rate and coronary flow. An i.v. dose of 0.1 mg/kg of LY175326 caused 54 and 95% increases in contractility in either the anesthetized cat or dog, respectively; corresponding heart rates were increased by less than 10%. Oral administration of 0.5 mg/kg to dogs was associated with an inotropic response that was maximal between 60 and 90 min and lasted in excess of 3 hr. These effects were not accompanied by increases in heart rate, gross behavioral changes or emesis. The pharmacology of LY175326 was evaluated in a propranolol-induced heart failure model using anesthetized beagle dogs. A bolus injection of 0.15 mg/kg of LY175326 followed by an infusion of 0.4 mg/kg/hr reversed the hemodynamic symptoms of heart failure by increasing left ventricular dP/dt60, cardiac output and stroke volume and reducing left atrial filling pressure and vascular resistance; heart rate was unchanged and calculated myocardial oxygen consumption was reduced. This balance of inotropic:vasodilator activities may provide a means of improving cardiac function while maintaining the myocardial oxygen supply:demand.

Biochemical studies on rabbits with aluminium induced neurofilament accumulations

The activities of acid phosphatase, hexosaminidase, beta-galactosidase, Mg2+-stimulated Na+K+ATPase, fumarase and ATP:citrate lyase were measured in grey matter of rabbit spinal cord 7-8 days after intra-ventricular or intra-cisternal injection of aluminium. RNA, DNA, and water content were measured in whole spinal cords. Choline acetyltransferase (CAT) and acetylcholinesterase were assayed in dorsal grey matter of the cord, which contained no aluminium-induced neurofilament accumulations (NFAs), and ventral grey matter, which had large numbers of such NFAs. CAT was also assayed in the hypoglossal nerve. None of these measures were consistently altered in the aluminium treated rabbits, although the activity of beta-galactosidase was increased in the NFA-free caudate nucleus of rabbits given aluminium intra-ventricularly, possibly due to the presence of phagocytes on the ventricular surface of the caudate. It is concluded that neither aluminium nor its induced NFAs has a gross effect on neuronal metabolism within 7-8 days.

A comparison of the cardiotonic effects of AR-L115 and AR-L57: evidence for distinct inotropic mechanisms

AR-L57 and AR-L115 have been of interest as inotropic agents for management of heart failure. Although their physiological effects are well documented, their mechanism(s) of action are unclear. Both AR-L57 and AR-L115 increased contractile force of cat papillary muscles in concentration-dependent manners; these effects were independent of either alpha- or beta-adrenoceptor stimulation. To determine if these effects occurred via a cAMP-dependent mechanism, cardiotonic actions were studied in the presence of carbachol. Muscarinic stimulation of papillary muscles attenuated contractile responses to AR-L115 thus implying a cAMP-mediated response. By contrast, carbachol did not alter the dose-response profile to AR-L57. In addition, AR-L115 potentiated the inotropic actions of isoproterenol whereas AR-L57 was ineffective. Both AR-L57 and ouabain increased diastolic resting tension in papillary muscles--a phenomenon associated with a state of Ca2+ overload; AR-L115 was without effect. In anesthetized dogs, i.v. AR-L57 and AR-L115 increased contractility and heart rate while reducing mean arterial blood pressure. Both agents had similar rates of onset (10-15 s) and durations of action (40-60 min). Although in vitro studies clearly indicate that AR-L57 and AR-L115 enhance inotropic state by distinct mechanisms, their in vivo cardiovascular profiles are comparable.

Amrinone in the treatment of chronic cardiac failure

The efficacy and safety of oral amrinone were examined in 17 patients with moderately severe to severe heart failure that was refractory to standard medical therapy and vasodilators. The short-term and 28 week response to open amrinone therapy was assessed first, followed by a placebo-controlled, double-blind withdrawal study of two 13 week stages in nine patients. Rest and exercise ventricular function were determined before and after 32 hours of amrinone; aerobic capacity was serially assessed. After 2 hours, 1.64 mg/kg amrinone produced a 40% (p less than 0.001) increase in cardiac output and a 32% (p less than 0.02) decrease in pulmonary wedge pressure without altering heart rate or blood pressure. The exercise cardiac index-wedge pressure curve obtained 32 hours after the first oral dose was significantly shifted (p less than 0.05) above control values. A sustained improvement in maximal oxygen uptake was noted during long-term open amrinone therapy. Subsequently, seven of the patients randomized to placebo therapy had a significant deterioration of symptoms or exercise tolerance, or both. After 4 weeks of readministration of amrinone, clinical stability was once again established and exercise tolerance was improved by Weeks 8 to 16. Adverse effects of thrombocytopenia (one patient) and hepatic dysfunction (one patient) attributable to amrinone were observed. It is concluded that amrinone is effective in the long-term treatment of chronic cardiac failure.

Jugular foramen syndrome as a complication of metastatic cancer of the prostate

The jugular foramen syndrome results from paralysis of various combinations of any of the last four cranial nerves. While trauma, vascular disease, and infection may be etiologic, most cases result from malignancies, usually metastatic. We have described a case of metastatic adenocarcinoma of the prostate resulting in the Collet-Sicard variant of this syndrome.

Generalized primary parathyroid hyperplasia: studies of the evolution of autogenous parathyroid graft function

The functional evolution of autogenous parathyroid grafts was monitored in six patients with primary parathyroid hyperplasia using a sensitive radioimmunoassay specific for the midregion of parathyroid hormone (PTH). After successful total parathyroidectomy and graft implantation in the forearm, basal immunoreactive PTH (iPTH) fell to undetectable levels for about 12 to 18 weeks, and then rose to normal. By 3 weeks after surgery, an iPTH increment appeared in venous blood from the arm bearing the graft. Graft function was demonstrated in all six cases. Graft-independent hypercalcemia occurred in two patients and appeared to inhibit PTH secretion by the graft. In one case, elevated levels of calcium and iPTH persisted after surgery but iPTH remained equal in both arms. At 5 months, a fifth hyperplastic gland was resected from the mediastinum, and the calcium level decreased to normal; the parathyroid implant was secreting iPTH vigorously 5 days later. Hypercalcemia had not prevented establishment of a viable implant. In the second case, hypercalcemia developed 80 weeks after operation, and the previously demonstrated iPTH gradient disappeared; presumably a fifth gland had become hyperplastic. In this patient, iPTH had remained in the upper portion of the normal range during the first postoperative week, probably indicating the potential for recurrence. Each of the other five patients remains normocalcemic 4 to 103 weeks after grafting.

Plasma acid-base patterns in diabetic ketoacidosis

In a study of the types of plasma acid-base patterns present at 196 admissions for diabetic ketoacidosis we found no relation between the initial level of serum total carbon dioxide and the plasma anion gap; instead, there was a broad spectrum of acid-base patterns, ranging from pure anion-gap acidosis to pure hyperchloremic acidosis. Although the degree of renal dysfunction on admission, which reflected the magnitude of volume depletion, was independent of the severity of metabolic acidosis, it was responsible for the variable retention of plasma ketones: the more severe the volume depletion on admission, the greater the ketone retention and the less prominent the hyperchloremic acidosis. Recovery from acidosis was significantly slower in patients admitted with pure hyperchloremic acidosis. After therapy, hyperchloremia developed in most patients at four to eight hours after admission, because of the retention of chloride in excess of sodium and the excretion of ketones by the kidney.

Reduplicative paramnesia: a disconnection syndrome of memory

A case of post-traumatic reduplicative paramnesia (Capgras syndrome) is presented in which the patient experiences duplications in all three spheres of orientation (time, place, person). We postulate that these duplications are the result of a disconnection of new memory registration from past memory stores. The patient is unable to integrate present cues with premorbid experience, and bases judgments of his present orientation upon recollections from the past. A deep lesion at the right posterior hippocampus and temporo-parieto-occipital junction is suggested as the site of this postulated primary memory disconnection, based upon neuropsychological testing and CAT scan results. This right temporal atrophy and memory disconnection appears to have induced immature personality changes.

Cognitive improvement associated with tricyclic antidepressant treatment of childhood major depressive illness

11 children fulfilling DSM-III criteria for major depressive illness were administered detailed neuropsychological batteries prior to and 3 to 6 mo. after starting tricyclic antidepressant treatment. Remission of depressive illness in children with melancholic major depression was associated with significant improvement in WISC-R Verbal IQ and Performance IQ, and on the Similarities, Comprehension, Block Design, and Coding subtests. In addition, there were significant improvements on the Halstead Categories test, on the Visual Reception subtest of the Illinois Test of Psycholinguistic Abilities, and in response latencies on the Matching Familiar Figures test. Two children with evidence of mild left hemiparesis showed amelioration of hemiparesis during tricyclic antidepressant treatment.

Myotonic dystrophy as a disease of abnormal membrane receptors: an hypothesis of pathophysiology and a new approach to treatment

Muscle weakness, clinical myotonia, and multiple systemic organ disturbances characterize myotonic dystrophy. Many of these systemic disturbances involve target organ insensitivity to aminergic or peptidergic (hormonal) stimulation. Reduced density or impaired function of aminergic and peptidergic (hormonal) receptors throughout the body may underlie this disorder. Tricyclic antidepressant augmentation of aminergic function ameliorates depressive symptoms, increases strength, and improves clinical myotonia in myotonic dystrophy patients.

Rubidazone in adults with previously treated acute leukemia and blast cell phase of chronic myelocytic leukemia: a Southwest Oncology Group Study

Rubidazone, a new anthracycline antibiotic, is the benzoyl hydrazone derivative of daunorubicin. The Southwest Oncology Group carried out a phase II study of the drug in 126 patients with previously treated acute leukemia; 116 patients were evaluable. Good-risk patients were given doses of 450 mg/m2, and poor-risk patients were given doses of 300 mg/m2 approximately every 3 weeks. No complete response was observed in 25 patients with chronic myelocytic leukemia blast cell transformation. In the remaining patients the overall complete response rate was 22% and the rate of complete plus partial response was 29%. In good-risk patients these rates were 27% and 35%, respectively. Toxicity was similar to that observed with other anthracyclines except that acute febrile reactions were more pronounced. On the basis of the results, there are plans for a large-scale comparison study of rubidazone versus doxorubicin, each in combination with cytarabine, vincristine, and prednisone.

Neuropsychological study of children during and after remission of endogenous depressive episodes

2 children experiencing endogenous depressive episodes show impaired cognitive functioning. Following tricyclic antidepressant-induced remission of depression, there was significant improvement in psychometric test performance.

Baker's antifol in combination with 5-fluorouracil and methyl-CCNU in the treatment of metastatic colorectal cancer: a Southwest Oncology Group Study (Protocol 7764)

Fifty-one previously untreated patients with metastatic colorectal cancer were treated with a combination of 5-fluorouracil, methyl-CCNU, and Baker's antifol. Six of 34 fully evaluable patients achieved a response. There were no apparent benefits obtained with this combination compared to treatment with 5-fluorouracil alone.

Action of clonidine on centrally evoked salivation in anaesthetized cats

1. Clonidine (4 microgram/kg) given intracisternally to anaesthetized cats inhibited brain stem-evoked parasympathetic submaxillary or parotid salivation by 62% at 5 Hz and 44% at 15 Hz. 2. The inhibitory action of clonidine on salivation was equally prevented by pretreatment with either intracisternal yohimbine (175 microgram/kg) or phentolamine (250 microgram/kg), used as preferential pre- and post-synaptic alpha-adrenoreceptor-blocking drugs respectively. 3. the inhibition of centrally evoked salivation by clonidine is due to an action on alpha-adrenoreceptors but no clear evidence was obtained to indicate whether these were located pre- or post-synaptically. This is in contrast to the preferential presynaptic action of clonidine in reducing peripheral parasympathetic nerve-evoked salivation.

Amine metabolites in ventricular cerebrospinal fluid in coma

The concentrations of homovanillic acid (HVA), 3-methoxy, 4-hydroxyphenylglycol (MHPG), and 5-hydroxyindolylacetic acid (5-HIAA) were measured in samples of ventricular cerebrospinal fluid (CSF) taken from 15 patients who were comatose as a result of an acute head injury, a tumour, or a cerebrovascular accident. The metabolite levels were not related to the ventricular fluid pressure. In the eight patients who recovered and from whom serial samples of CSF were obtained, the metabolite levels did not change, except for two patients in whom HVA increased as coma progressed. The concentration of MHPG, but not of HVA or 5-HIAA, was greater (P less than 0.02) in the five patients who died without regaining consciousness than in the 10 patients who recovered.

The mechanism of the clonidine-induced reduction in peripheral parasympathetic submaxillary salivation

The mechanism of the clonidine induced reduction in submaxillary salivation evoked by electrical stimulation of the chorda tympani was investigated in anaesthetised cats. This effect of clonidine was found to be dose and frequency dependent. In addition to clonidine, tramazoline, also a preferential presynaptic alpha-adrenoceptor agonist, produced a reduction in electricallly evoked salivation. Methoxamine, noradrenaline and naphazoline, which are less potent presynaptic alpha-receptor agonists, caused increases in salivation. Phentolamine only partially antagonized the decrease in salivation produced by clonidine whereas it was virtually abolished by yohimbine. Clonidine increased salivation evoked by intra-arterial injections of carbachol. These findings suggest that clonidine reduces peripheral parasympathetically evoked submaxillary salivation by activation of presynaptic alpha-adrenoceptors which inhibit cholinergic transmission.