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Biomedical subjects

J W Mason

Publications and source records attributed to J W Mason.

At least 73 records · Page 4Linked to original sources
PubMed1989

Immunosuppression and beta-blockade in heart failure.

Two potential treatments, immunosuppression for myocarditis and beta-adrenergic blockade for heart failure, have been advocated. However, definitive conclusions await the result of ongoing large, multicenter, randomized clinical trials. There is circumstantial evidence that myocarditis may be a common precursor of dilated cardiomyopathy. Animal studies of myocarditis suggest that critically timed immunosuppression may be an effective therapy. Although promising, clinical studies to date are small and mostly uncontrolled. Clinical studies have demonstrated that beta-blockers are generally well tolerated in heart failure, and long-term treatment may result in improved symptomatic and functional status. These effects may be due to antagonism of direct and indirect effects of chronic reflex sympathetic stimulation on the cardiovascular system, including down-regulation of the myocardial beta-adrenergic receptor. However, prolongation of survival has not been documented by any studies. Initiation of beta-blockade requires careful patient selection and titration with small initial doses of metoprolol.

Adrenergic beta-Antagonists↗
PubMed1989

Diagnosing and treating active myocarditis.

The treatment of dilated cardiomyopathy is palliative and, hence, has little effect on the natural history. Therapy directed toward the cause rather than the effect will be necessary before mortality can be affected. Active myocarditis is postulated to be the cause of dilated cardiomyopathy in a subset of patients. A model of murine coxsackievirus B3 myocarditis has immunopathogenic parallels to the disease in humans and suggests that persistent autoimmune reactivity following viral clearance leads to progressive myocyte damage and dilated cardiomyopathy. In preliminary uncontrolled studies, patients with myocarditis have shown clinical and histologic improvement with the addition of immunosuppressive therapy, but there may also be a significant rate of spontaneous improvement. A multicenter study currently acquiring patients is designed to determine the efficacy of immunosuppression and the natural history of active myocarditis.

Clinical Trials as Topic↗
PubMed1988

Prognostic significance of arrhythmia inducibility or noninducibility at initial electrophysiologic study in survivors of cardiac arrest.

The value of arrhythmia inducibility or noninducibility at initial electrophysiologic study to predict the likelihood of arrhythmia recurrence was assessed in 150 consecutive survivors of cardiac arrest. Ventricular tachycardia (greater than or equal to 6 beats) or ventricular fibrilation was induced in 113 patients (75%); ventricular arrhythmia could not be induced in 37 patients (25%). During follow-up of a mean of 16 months (range 1 to 72), there were 65 arrhythmia recurrences, 34 of them fatal, in 58 patients. Multivariate regression analysis showed that inducibility at initial study of ventricular tachycardia or ventricular fibrilation was an independent predictor of total arrhythmia recurrence (p less than 0.0001) and fatal arrhythmia recurrence (p = 0.02). At 1 year, 25 +/- 5% of patients with an inducible arrhythmia had a fatal arrhythmia recurrence compared with only 4 +/- 4% of patients without (p = 0.003). The nature of the inducible arrhythmia had no additional predictive value. Inducibility or noninducibility of ventricular arrhythmias at initial electrophysiologic study is a powerful, independent predictor of subsequent arrhythmia recurrence in survivors of cardiac arrest. Patients without inducible arrhythmias have a low frequency of fatal arrhythmia recurrence.

Arrhythmias, Cardiac↗
PubMed1988

Serum testosterone differences between patients with schizophrenia and those with affective disorder.

Serum testosterone levels (ng/dl) were measured at 2-week intervals during the course of hospitalization in 35 male inpatients in the following four diagnostic groups: undifferentiated schizophrenia, paranoid schizophrenia, bipolar I disorder-manic, and major depressive disorder (endogenous type). The mean (+/- SE) testosterone levels during hospitalization were significantly higher (p less than 0.001) in the schizophrenic patients (510 +/- 38) than in the affective disorder patients (347 +/- 25). This difference persisted throughout hospitalization, being present in the first sample following admission (p less than 0.03) and the final sample before discharge (p less than 0.01). The above group differences were largely due to high testosterone levels in the paranoid schizophrenic subgroup (mean +/- SE level of 559 +/- 41). A longitudinal, as well as cross-sectional, view of the hormonal and clinical data suggests that the testosterone system is linked to both state and trait psychological factors, and this issue is discussed in the light of prior basic psychoendocrine research on this system. The potential application of these findings for new approaches to the development of biological criteria for psychiatric diagnosis is discussed.

Adult↗
PubMed1988

Preclinical evaluation of the abdominal aortic counterpulsation device.

A valveless, single-orifice abdominal aortic counterpulsation device (AACD) was implanted retroperitoneally on the abdominal aorta and was pumped continuously, providing aortic diastolic augmentation for 45 +/- 4.9 days in four calves (group A). The hematocrit, lactate dehydrogenase (LDH), bilirubin, blood urea nitrogen, and creatinine were obtained before implantation and weekly thereafter. Biocompatibility data were compared to those obtained from 11 calves (group B) that received a total artificial heart (TAH) and were electively terminated 50.0 +/- 19.5 days after implantation. The hematocrit values in the first week were 20.9 +/- 11.5% and 39.8 +/- 11.5% below control values for group A and group B, respectively (p less than 0.02); in the sixth week they were 5.1 +/- 14.6% above control values (group A) and 22.6 +/- 9.0% below control values (group B) (p less than 0.05). LDH did not change in group A, while in group B it was constantly about 100% above control values. Autopsy revealed one to three infarcts 1 to 3 mm in diameter in 63% of the kidneys in group A, while in all of group B kidneys there were multiple infarcts of more than 10 mm. After the induction of left ventricular (LV) failure, the AACD decreased the LV end-diastolic pressure (EDP) by 21.2% (p less than 0.005) and the aortic (AO) EDP by 18% (p less than 0.005). It increased the endocardial viability ratio by 300% (p less than 0.0005), and the cardiac index by 66.9% (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Clinical predictors of arrhythmia inducibility in survivors of cardiac arrest: importance of gender and prior myocardial infarction.

Clinical characteristics that correlate with arrhythmia inducibility were determined in 150 consecutive survivors of cardiac arrest. All underwent electrophysiologic study with a uniform protocol when they were not receiving antiarrhythmic drugs. A ventricular tachyarrhythmia (sustained monomorphic ventricular tachycardia, ventricular fibrillation or nonsustained ventricular tachycardia) was induced in 113 patients (75%). The strongest correlates of inducing a tachyarrhythmia were male gender (p less than 0.0001) and a history of prior myocardial infarction (p less than 0.0001). Induction of sustained monomorphic tachycardia alone was also strongly related to gender and prior infarction; in particular, none of 26 women without prior infarction had induction of sustained monomorphic ventricular tachycardia. Among patients with induced sustained tachyarrhythmias, those with induced monomorphic ventricular tachycardia were distinguished from those with induced ventricular fibrillation in they were more likely to have coronary artery disease (p = 0.0001), healed myocardial infarction (p = 0.0002), left ventricular aneurysm (p = 0.0007) and ventricular tachycardia documented at the time of cardiac arrest (p = 0.02). Other variables showing significant correlations with arrhythmia inducibility were ejection fraction, documentation of ventricular tachycardia at the time of cardiac arrest and presence of an intraventricular conduction delay. However, stepwise logistic regression identified male gender and healed myocardial infarction as the only independent predictors of arrhythmia inducibility. On the basis of these two variables alone, arrhythmia inducibility or noninducibility could be correctly predicted in 89% of the patients in this series.

Arrhythmias, Cardiac↗
PubMed1988

Elevation of urinary norepinephrine/cortisol ratio in posttraumatic stress disorder.

We have previously reported the unusual combination of low urinary free cortisol levels with high urinary norepinephrine excretion in posttraumatic stress disorder (PTSD) patients in comparison with four other patient groups: major depressive disorder, endogenous type; bipolar I, manic; paranoid schizophrenia; undifferentiated schizophrenia. Cortisol levels alone did not distinguish PTSD from paranoid schizophrenia patients and norepinephrine levels alone did not distinguish PTSD from bipolar I, manic, patients. In further consideration of these findings, we have found that combining the values for the two systems in a norepinephrine/cortisol (N/C) ratio provides a measure that significantly distinguishes PTSD from all the other patient groups throughout the hospitalization period. The N/C ratio was more than twice as high in the PTSD group than in all the other patient groups in the first sample following hospital admission, in the mean sample during hospitalization, and in the last sample before discharge. The mean N/C ratio for the PTSD group was 2.54, compared with a mean of .99 for the other four groups, which ranged from .81 to 1.18. The diagnostic sensitivity was 78% and the specificity was 94% for correct classification of PTSD in our sample. These preliminary findings yield further encouragement for exploring multivariate strategies, using hormonal ratios or profiles, in an effort to increase the diagnostic sensitivity of neuroendocrine criteria in the assessment of psychiatric patients.

Combat Disorders↗
PubMed1988

Relationship of age to TSH response to TRH in depressed men.

The relationship between age and TSH response to TRH was studied in 40 men with unipolar major depressive disorder (range 24-65 years, mean 44.7 years) and 36 healthy male volunteers of similar ages. Both groups were subdivided into younger and older than 40 years of age. "Blunted" TSH response to TRH was observed in 58% of depressed men and in 28% of controls, using a dTSH maximum of less than or equal to 6 microU/ml as a cut-off criterion. Older healthy men had a higher blunting rate (40%) than the younger group (19%). In depressed patients, by contrast, the blunting rate was 50% in the older group and 65% in the younger group. Higher mean maximum dTSH, higher basal TSH and lower mean circulating FT4 levels were also noted in older depressed men, suggestive of a subtle thyroid subsensitivity to TSH stimulation and subclinical primary hypothyroidism that may have contributed to the depression. Age is known to be a confounder of TRH test results. There may be a subset of depressed patients over 40 where the confounding effect of age is associated with an exaggerated, rather than decreased TSH response to TRH.

Adult↗
PubMed1988

Neuroendocrine aspects of suicidal behavior.

To assess biologic risk factors in suicidal behavior accurately, it is necessary to distinguish prospective from retrospective design. The former studies are more likely to elicit information concerning possible risk factors in suicide, whereas the latter may be better indicators of biologic traits. In both types of investigations, measures taken close to the suicide attempt are more likely to reflect the biologic state of the individual at the time of the behavior. Although the abnormalities present in suicidal individuals are not entirely clear, most evidence to date suggests an overactivity of the hypothalamic-pituitary-adrenal axis and a dysregulation of both serotonin and adrenergic metabolism. These systems are interrelated. Both animal and human studies have established that a multivariate biologic approach is necessary to the understanding of the pathophysiology of suicide.

Dexamethasone↗
PubMed1988

Neuroendocrine aspects of suicidal behavior.

To assess biologic risk factors in suicidal behavior accurately, it is necessary to distinguish prospective from retrospective designs. The former studies are more likely to elicit information concerning possible risk factors in suicide, whereas the latter may be better indicators of biologic traits. In both types of investigations, measures taken close to the suicide attempt are more likely to reflect the biologic state of the individual at the time of the behavior. Although the abnormalities present in suicidal individuals are not entirely clear, most evidence to date suggests an overactivity of the hypothalamic-pituitary-adrenal axis and a dysregulation of both serotonin and adrenergic metabolism. These systems are interrelated. Both animal and human studies have established that a multivariate biologic approach is necessary to the understanding of the pathophysiology of suicide.

Adrenal Cortex Hormones↗
PubMed1987

Features of cardiac arrest episodes with and without acute myocardial infarction in the Coronary Artery Surgery Study (CASS).

Angiographic evidence of coronary artery disease was present in 16,002 patients in the Coronary Artery Surgery Study (CASS) registry. Of these patients, 551 had a history of cardiac arrest before enrollment angiography. Cardiac arrest was a complication of acute myocardial infarction (AMI) in 372 patients (68%). Electrocardiographic documentation of the responsible rhythm was available in 283 patients. Ventricular fibrillation (VF) was present in 112 (60%), ventricular tachycardia (VT) in 41 (22%) and both VT and VF in 26 (14%) patients. Stepwise linear discriminant analysis comparing the 551 cardiac arrest patients with the other 15,451 patients selected left ventricular wall motion score (F = 265), use of digitalis (F = 71), impaired blood supply to any segment (F = 16) and particularly to the anterior wall (F = 11) as discriminating variables associated with cardiac arrest. Patients with cardiac arrest occurring as a complication of AMI were younger (F = 12), had greater impairment of coronary blood supply (F = 7) and were more likely to be on a cholesterol-lowering diet (F = 16) than were patients with arrest remote from infarction. Comparison of patients with VT versus those with VF showed a positive association of VT with age (F = 8), a trend toward worse left ventricular function and presence of a left ventricular aneurysm, but no difference in severity and collateralization of coronary artery disease. It is concluded that cardiac arrest is related to the extent of myocardial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Acute hemodynamic response to low dose enoximone (MDL 17,043): an oral dose-range study.

The efficacy of low dose oral enoximone (MDL 17,043) was evaluated in the treatment of congestive heart failure (CHF). Fourteen male patients with stable, moderately severe CHF (New York Heart Association functional class II or III) and mean left ventricular ejection fraction of 0.21 +/- 0.02 were randomized to receive 50, 75, 100, 150 or 200 mg of enoximone (mean dose 1.46 +/- 0.16 mg/kg). Hemodynamic data were measured before and during the first 24 hours of therapy. An oral dose was given in the first 24 hours, and then every 8 hours. Acute administration of enoximone resulted in significant improvement in cardiac index (2.07 +/- 0.18 to 2.36 +/- 0.16 liters/min/m2, p less than 0.05), mean pulmonary arterial pressure (35 +/- 4 to 30 +/- 4 mm Hg, p less than 0.02), mean pulmonary artery wedge pressure (22 +/- 3 to 18 +/- 2 mm Hg, p less than 0.05) and systemic vascular resistance (1,712 +/- 148 to 1,384 +/- 82 dynes s cm-5, p less than 0.02). Neither hypotension nor tachycardia was observed. Although there was a trend toward a dose-response relation, hemodynamic responses to doses less than 1.5 mg/kg and greater than 1.5 mg/kg were not significantly different. Clinical symptoms improved with long-term therapy, but left ventricular ejection fraction and exercise treadmill time did not change. In patients with moderate and severe CHF, low doses of enoximone result in significant acute hemodynamic improvement.

Administration, Oral↗
PubMed1987

Amiodarone.

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Amiodarone↗
PubMed1987

Sex differences in prolactin change during mourning.

Fourteen men and 12 women were interviewed eight weeks after conjugal bereavement to discuss the events prior to the spouse's death and the subsequent bereavement period. Prolactin (PRL) was measured at the beginning and end of the interview. Descriptions of the deceased spouse were obtained during the interview and rated for Developmental Level of Object Representation (DLOR), a measure of the cognitive complexity of the description. There were significant correlations between DLOR and PRL change for both men and women but the correlation for women was positive and the correlation for men was negative. These findings extend the literature on the psychological correlates of PRL change and suggest that the physiological changes associated with mourning are different for men and women.

Female↗
PubMed1987

Sustained urinary norepinephrine and epinephrine elevation in post-traumatic stress disorder.

Urinary norepinephrine and epinephrine levels (microgram/day) were measured at two-week intervals during the course of hospitalization in the following patient groups: post-traumatic stress disorder (PTSD); major depressive disorder (MDD); bipolar I, manic (BP); paranoid schizophrenia (PS); and undifferentiated schizophrenia (US). The mean norepinephrine level during hospitalization was significantly higher in PTSD (76 +/- 10.4 micrograms/day) than in BP (60.6 +/- 8.4 micrograms/day), MDD (41.2 +/- 4.7 micrograms/day), PS (33.4 +/- 4.9 micrograms/day) and US (34.3 +/- 5.9 micrograms/day) groups, according to Duncan's multiple range test, (F(4,39) = 6.94, p less than 0.0003). The norepinephrine elevations in the PTSD group were sustained throughout hospitalization. The only other group to show mean levels in this range was the BP group in the first sample after hospital admission. This finding supports prior psychophysiological studies indicating increased sympathetic nervous system activity in PTSD patients. The mean epinephrine level during hospitalization was also significantly higher in PTSD (22.7 +/- 2.4 micrograms/day) than in MDD (13.6 +/- 1.7 micrograms/day), PS (14.7 +/- 2.4 micrograms/day), and US (18.9 +/- 1.8 micrograms/day), but not higher than in BP (21.5 +/- 2.7 micrograms/day). The relationship of epinephrine levels among diagnostic groups was sustained throughout hospitalization. It appears likely that the main underlying mechanisms for elevations of both hormones are psychological, but further work will be required to establish the exact nature of these mechanisms.

Animals↗