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Biomedical subjects

J L Anderson

Publications and source records attributed to J L Anderson.

At least 253 records · Page 14Linked to original sources
PubMed1986

Effects of bright incandescent light on seasonal and nonseasonal major depressive disorder.

Previous research has indicated that exposure to bright fluorescent light can benefit clinically depressed individuals. The present study, a 1- to 2-week open trial of bright (greater than or equal to 2,000 lux) incandescent light with seasonal (fall/winter) and nonseasonal depressives, produced a therapeutic effect on seasonal depression, as measured by three criteria for recovery: final score on the Hamilton Rating Scale for Depression (HRSD) less than 10; final HRSD score less than or equal to 50% of pretreatment HRSD score; no longer meets DSM-III criteria for major depressive disorder. Phototherapy was not effective in the nonseasonal patients, whose functioning was more impaired than that of the seasonal subjects even before the trial. No adverse effects were observed in any patient.

Adult↗
PubMed1986

Coronary bypass surgery early after thrombolytic therapy for acute myocardial infarction.

The safety of coronary bypass operations after coronary reperfusion with streptokinase for acute myocardial infarction is not well documented. Therefore we studied 23 consecutive patients (mean age, 59.5 years; 22 men) undergoing bypass operations a median of 5 days (range, 1 to 23 days) after thrombolysis (streptokinase). The control group consisted of 169 concurrent patients of similar mean age (58.8 years) having bypass operations for standard indications. The preoperative angiographic ejection fraction was 68 +/- 14% in the control patients and 61 +/- 14% in the streptokinase group (p less than 0.05). The number of diseased vessels (70% stenosis or greater) averaged 2.6 in control and 2.3 in streptokinase patients. A previous myocardial infarction had occurred in 42% of the controls and all of the streptokinase patients. Aortic cross-clamp times did not differ between the two groups (80 +/- 35 minutes for the controls and 68 +/- 25 minutes for the streptokinase group). Cardiopulmonary bypass times were similar: 108 +/- 45 minutes in the controls versus 109 +/- 28 minutes in the streptokinase group. Grafts per patient averaged 3.7 +/- 1.5 for the controls versus 2.8 +/- 1.1 for the streptokinase patients (p less than 0.01). Difficult operative hemostasis was noted in 4% of both groups. Inotropic support was given postoperatively to 11% of the control and 13% of the streptokinase patients (p = not significant). Measured blood loss during the first 48 hours postoperatively was similar, averaging 809 ml in controls and 776 ml in the streptokinase group. Blood product replacement was also comparable: mean, 713 ml in the control group versus 759 ml in the streptokinase group.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Bypass↗
PubMed1986

Recainam, a potent new antiarrhythmic agent: effects on complex ventricular arrhythmias.

The antiarrhythmic efficacy and safety of intravenous recainam, a newly synthesized compound displaying potent class I antiarrhythmic activity, were tested in 10 hospitalized patients with frequent (greater than 30/h) complex ventricular ectopic beats. There were seven men and three women of average age 57 years (range 21 to 74); five had ischemic heart disease, three had cardiomyopathy and two had valvular heart disease. Recainam was given as a 3.0 mg/kg per 40 min loading infusion followed by a 0.9 mg/kg per h maintenance infusion over a 24 hour observation period. Arrhythmia response was assessed both in the short term (comparing 2 hours before and 1 hour after drug loading) and in the long term (comparing 48 hours before drug loading and 23 hours of maintenance infusion). The median frequency of total premature ventricular complexes decreased in the short term by 99.6% (from 392.5 to 1.5/h, p less than 0.005) and in the long term by 99.7% (from 435 to 1.3/h, p less than 0.01). Repetitive beats were suppressed by a median of 100% both in the short term (p less than 0.006) and during 24 hour infusion (from 80.9 to 0/h, p less than 0.003). More than 90% suppression of repetitive beats occurred in all 10 patients (100%) and more than 90% suppression of total arrhythmias occurred in 9 patients (90%) during the maintenance period. Electrocardiographic PR and QRS intervals increased by 19% (p less than 0.001) and 24% (p less than 0.003), respectively, during therapy, but the JTc interval decreased (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Quantification of aortic regurgitation utilizing continuous wave Doppler ultrasound.

Aortic regurgitation and mitral stenosis are hemodynamically similar, insofar as both result in passive ventricular filling across a narrow orifice driven by a declining pressure gradient. Because mitral stenosis is successfully characterized by Doppler ultrasound determination of the velocity half-time, or time constant, aortic regurgitation might be quantified in an analogous fashion. Eighty-six patients with diverse causes of aortic regurgitation underwent continuous wave Doppler examination before cardiac catheterization or urgent aortic valve replacement. The Doppler velocity half-time was defined as the time required for the diastolic aortic regurgitation velocity profile to decay by 29%, whereas catheterization pressure half-time was calculated as the time required for transvalvular pressure to decay by 50%. Doppler velocity and catheterization pressure half-times were linearly related (r = 0.91). Doppler velocity half-times were inversely related to regurgitant fraction (r = -0.88). Angiographic severity (1+ = mild to 4+ = severe) was also inversely related to pressure and velocity half-time; a Doppler half-time threshold of 400 ms separated mild (1+, 2+) from significant (3+, 4+) aortic regurgitation with high specificity (0.92) and predictive value (0.90). The Doppler velocity half-time was independent of pulse pressure, mean arterial pressure, ejection fraction and left ventricular end-diastolic pressure. Estimation of transvalvular aortic pressure half-time utilizing continuous wave Doppler ultrasound is a reliable and accurate method for the noninvasive evaluation of the severity of aortic regurgitation.

Acute Disease↗
PubMed1986

Classification by type of ventricular arrhythmia predicts frequency of adverse cardiac events from flecainide.

Antiarrhythmic therapy is known to be associated with a significant risk of adverse cardiac reactions, including a proarrhythmic response. This study assessed in 1,330 patients followed up for 292 +/- 393 days the predictive value for cardiovascular safety of a system by which patients were classified according to ventricular arrhythmias on entry, presence or absence of organic heart disease and drug dose for flecainide acetate. Baseline arrhythmia subgroups included patients with premature ventricular complexes only, nonsustained ventricular tachycardia, and sustained ventricular tachycardia. Proarrhythmic events occurred in 6.8% of patients overall and were serious in 2.3% and lethal in 1.0%. However, proarrhythmia was highly dependent on arrhythmia class on entry: serious nonlethal proarrhythmic events occurred in 6.6% of patients with sustained ventricular tachycardia, only 0.9% with nonsustained ventricular tachycardia and 0% with premature ventricular complexes (p less than 0.01). Proarrhythmic death occurred in 3.1% of patients with sustained ventricular tachycardia, 0.2% with nonsustained ventricular tachycardia and 0% with premature ventricular complexes only (p less than 0.01). Proarrhythmia was also influenced by the presence of structural heart disease: serious nonlethal proarrhythmia occurred in 2.6% of patients with versus 0.4% of those without organic heart disease, and death occurred in 1.2 versus 0%, respectively. These adverse events were also dependent on dosing regimen. Flecainide caused premature discontinuation due to new or worsened heart failure in 1.4% of patients, all with underlying organic heart disease; however, heart failure was not clearly related to dose or type of arrhythmia. Symptomatic conduction disturbances occurred in 2.2%, and were predicted by preexistent sinus node disease but not by other baseline features.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1986

Multicenter trial of sotalol for suppression of frequent, complex ventricular arrhythmias: a double-blind, randomized, placebo-controlled evaluation of two doses.

Sotalol is a unique beta-adrenergic blocking agent with additional actions characteristic of Vaughn-Williams class III antiarrhythmic agents in experimental models. To test the efficacy of sotalol to suppress ventricular arrhythmias, a 6 week parallel, placebo-controlled out-patient study of two doses (320 and 640 mg/day, in two divided doses) was performed in four hospitals in 56 patients with chronic premature ventricular complexes at a frequency of 30/h or more (mean +/- SE, 528 +/- 60/h) on 48 hour ambulatory electrocardiographic recording. During a placebo week, no change occurred in arrhythmia frequency (532 +/- 76/h). Subsequent sotalol therapy significantly reduced median arrhythmia frequency in patients receiving both low (n = 19) and high (n = 18) doses compared with that in patients receiving placebo (by 77 and 83%, respectively, versus 6%; p less than 0.001). Twenty-two (59%) of 37 sotalol-treated patients, 11 in each group, reached the prospectively defined criterion of efficacy (greater than or equal to 75% arrhythmia reduction) versus 2 (11%) of 19 placebo control patients (p less than 0.001). Sotalol reduced the median frequency of couplets by 94% (p less than 0.0001) and that of runs by 89% (p less than 0.0007). The electrocardiographic effects of sotalol included reductions in heart rate (by 17 to 27%) and increases in the QTc (by 6 to 9%) and PR (by 6%) intervals. Ejection fraction was unchanged. The most common adverse side effect was fatigue, but drug discontinuation was required in only three patients taking 640 mg/day. No proarrhythmic events or biochemical abnormalities were observed. In summary, sotalol displays significant antiarrhythmic activity of moderately high degree with good tolerance in doses of both 320 and 640 mg/day. Its antiarrhythmic actions are distinguished from those reported for other beta-blockers by its effects on the QTc interval and its moderately high degree of antiarrhythmic activity.

Aged↗
PubMed1986

Transport mechanisms of biological colloids.

An effort was made to distinguish among various mechanisms by which colloidal particles can be transported through liquid solutions. Figures 1-3 provide a visual (Figure: see text) summary of these differences. The various "phoretic" motions (electrophoresis, diffusiophoresis, osmophoresis) differ from sedimentation in that the driving forces operate within a thin interfacial layer at the surface of a particle rather than on the bulk of the article. Because of these surface forces, the velocity field of solvent dragged by a particle undergoing phoretic motion is much weaker (O(r-3)) than in the case of sedimentation (O(r-1)). As a consequence, particle-particle and particle-pore interactions are weak for the phoretic motions; Figures 4 and 5 demonstrate this point. It should be emphasized that the results presented in this paper are strictly valid only for very thin interfacial layers (kappa-1 much less than a, L and K much less than a). The Einstein relation (Eq. 1), which applies to sedimentation and diffusion with Equation 2 used for f, has been incorrect for the phoretic transport. As shown in Table 2, there is no unique value of f that fits all the phenomena, and in fact the magnitude of f for phoretic motion greatly exceeds the Stokes' law coefficient. Unfortunately, Equation 1 is well ingrained in the literature; one objective here was to bring its inadequacies to light. The phoretic transport processes offer important advantages in separations because of the selectivity that may be achieved through surface chemistry. For example, experiments are underway that demonstrate transport of particles across porous membranes by diffusiophoresis. It may prove economically attractive to develop both analytical and preparative separation methods that rely more on the surface properties of biological colloids rather than just their size.

Biological Transport↗
PubMed1986

Changes in liver glutathione S-transferase activities in Coturnix quail fed municipal sludge-grown cabbage with reduced levels of glucosinolates.

Cabbage, green beans, or seeds from sunflowers grown either on municipal sewage sludge-amended soil or soil alone were fed to male and female Coturnix quail, as 50% of a complete diet, for 5 weeks. Specific activities of liver glutathione S-transferase (GST) were similar in all quail fed the latter two plant diets and also similar to quail fed a nonplant, control diet. Sludge-grown cabbage-treated quail exhibited liver GST activities significantly higher (P less than 0.05) than levels of liver GST in birds fed the other plants, with a further twofold activity increase in quail fed the soil-grown cabbage. This response seems to be correlated with the levels of glucosinolates present in the cabbage, i.e., 3040 and 9253 ppm (dry basis) in the sludge-grown and soil-grown cabbage, respectively.

Animal Feed↗
PubMed1986

Clinically silent atrial septal defects with evidence for cerebral embolization.

The cause of stroke in young patients frequently cannot be established. Eleven consecutive patients, age 50 and younger, had clinical evidence of cerebral embolization. Results of physical, radiographic, electrocardiographic, and two-dimensional echocardiographic examinations were normal in all patients. During normal respiration, eight of the patients had right-to-left shunts at the atrial level shown by microcavitation contrast two-dimensional echocardiography. Six of the eight patients with positive contrast studies had cardiac catheterization. Five of six patients had an atrial septal defect, normal right and left heart pressures, and small right-to-left shunts during a Valsalva strain. Four patients had surgical closure of the defect, which ranged in size from 5 to 10 mm. The remaining patients received anticoagulants. Interatrial communications appear to be common in young patients with stroke, suggesting paradoxical embolization as a possible mechanism. Contrast two-dimensional echocardiography should be done in such patients because it is the only noninvasive technique that reliably finds these defects.

Adolescent↗
PubMed1986

Subfractionation of human peripheral blood lymphocytes by partitioning in two-polymer aqueous phase systems. Characteristics of a small subpopulation of cells with high partition coefficient.

Mixtures of aqueous solutions of dextran and poly(ethylene glycol) form immiscible 2-phase systems that are suitable for the separation of viable, functionally-competent cells on the basis of their surface properties. With the appropriate choice of ionic composition, these systems will separate cells on the basis of charge-related surface characteristics. We have previously shown that in charge-sensitive phase systems, human B lymphocytes have a low partition coefficient (K) and T cells have an intermediate K. The cell subpopulation with the highest K values contains large null lymphocytes that have most of the antibody-dependent and natural killer activities. The present study further characterizes this latter cell subpopulation. 8-33% of peripheral blood lymphocytes in normal persons had high K values. About 50% of these cells had typical Giemsa-staining granules characteristic of killer cells and one third had Fc receptors, but lacked complement receptors. Although 15-30% of the cells with high K values formed rosettes with sheep erythrocytes, there was virtually no response to T-cell mitogens such as PHA and Con A. Mixing cells having high K values with mitogen-responsive T cells from intermediate cell fractions revealed no evidence of suppressor-cell activity to explain the poor mitogen response. The studies indicate that a heterogeneous population of cells share charge-related surface properties resulting in a high partition coefficient. These cells comprise a significant proportion of human peripheral blood lymphocytes and include virtually all of the large granular lymphocytes as well as a large population without this morphology that shares the feature of unresponsiveness to T-cell mitogens.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

Current clinical perspectives on antiarrhythmic drug therapy.

The approach of arrhythmia evaluation and therapy is rapidly changing because of new diagnostic approaches and new antiarrhythmic agents, and because of evolving concepts about arrhythmia risk. Ventricular arrhythmias and the degree of associated heart disease define three broad risk categories: benign, potentially lethal, and lethal arrhythmia groups. Benign arrhythmias require therapy only if symptomatic, and arrhythmias with lethal potential should always be aggressively treated. The approach to potentially lethal arrhythmias remains problematic. It is now clear that complex arrhythmias in the presence of advanced heart disease (e.g., myocardial infarction) signify an increased risk (two- to fourfold). The optimal approach to risk reduction, however, is uncertain, and empirical therapy with standard antiarrhythmic agents alone appears inadequate. Antiarrhythmic drugs may be classified into four groups based on electrophysiological and pharmacological effects, and class I (membrane-active) agents are now divided into three subgroups (classes IA, IB, and IC). Current agents are far from ideal. Four new agents, however, are becoming available: tocainide (1984) and mexiletine (1985-1986) (class IB, lidocaine congeners); flecainide (1985) (class IC); and amiodarone (1986) (class III). These agents will extend the current scope of antiarrhythmic therapy. Novel nonpharmacological therapies are also becoming increasingly important, including surgical and catheter ablation procedures after electrophysiological mapping, advanced pacemaker/cardioverter units for tachyarrhythmia termination, and automatic implantable defibrillator devices. These new developments promise more specific and successful arrhythmia management in the future.

Anti-Arrhythmia Agents↗
PubMed1986

Stability of levodopa in 5% dextrose injection at pH 5 or 6.

The stability of solutions of levodopa 1 mg/mL in 5% dextrose injection adjusted to pH 5 or 6 and stored at one of three temperatures was determined. Solutions were adjusted to pH 5 or 6 with sodium acetate injection or sodium phosphate injection, respectively. Three samples of solution adjusted to pH 5 were stored at each of three temperatures (4, 25, and 45 degrees C), and three samples of solution adjusted to pH 6 were stored at 25 degrees C. Samples were assayed for levodopa concentration by high-performance liquid chromatography at various times during the 21-day study period. All solutions maintained at least 90% of the initial concentration of levodopa for seven days. Discoloration of all solutions except those stored at 4 degrees C was noted at some point during the study period; solutions stored at 45 degrees C began to darken within 12 hours. The pH values of the solutions did not change during the study period. Under the conditions studied, solutions of levodopa 1 mg/mL in 5% dextrose injection adjusted to pH 5 or 6 are stable for seven days. Slight degradation of levodopa may cause a brownish-black discoloration of the admixtures.

Drug Stability↗
PubMed1986

Familial automaticity-conduction disorder with associated cardiomyopathy.

An unusually large family of European descent was afflicted over four generations by an automaticity and conduction disorder with an associated dilated cardiomyopathy of variable expression. Ten living members affected with the disorder and three presumed affected but dead members were identified. Typically, the disorder presented as a sinoatrial bradyarrhythmia/tachyarrhythmia syndrome, followed by atrial enlargement and, variably, ventricular enlargement and dysfunction. Three family members required pacemaker implantation. Longevity did not seem to be greatly affected, but the demonstrated potential for embolic cerebrovascular events stresses an associated morbidity. The familial incidence was best explained by autosomal dominant inheritance with incomplete penetrance (greater in males and usually occurring first in adolescence) and variable expressivity. The large size of the family, frequency and profile of disease manifestations and disease tracking through at least four generations are unusual features of the familial disease described.

Adolescent↗
PubMed1985

Hepatic glutathione S-transferase activity and aflatoxin B1-induced enzyme altered foci in rats fed fractions of brussels sprouts.

The aim of the present study was to determine whether the liver cytosol detoxication enzymes, glutathione S-transferases (GSTases) as well as gamma-glutamyl transpeptidase (GGT) foci induced by aflatoxin B1 (AFB) were changed by feeding weanling rats diets containing brussels sprouts, a glucosinolate fraction of brussels sprouts (extract), or a non-glucosinolate fraction (residue). All 3 of these diets induced high levels of hepatic GSTase specific activity as compared to purified-basal diet fed control rats. The brussels sprouts and the extract treatments, but not the residue dietary treatment, inhibited hepatic GGT foci induced by AFB. Thus, glucosinolates and non-glucosinolate fractions of brussels sprouts induce hepatic enzymes involved in detoxication mechanisms but the non-glucosinolate compound(s) apparently are not involved in all chemical carcinogen metabolic processes.

Aflatoxin B1↗
PubMed1985

Quantitation of lymphocyte subsets by immunofluorescence flow cytometry in idiopathic dilated cardiomyopathy.

Idiopathic dilated cardiomyopathy (IDC) is a disease in which immune aberration has been postulated but not confirmed. The frequency of lymphocyte subsets was evaluated in 22 patients with IDC and in 22 blood bank control subjects, using monoclonal antibodies to cell surface markers to allow cell sorting by immunofluorescence flow cytometry. Eighteen patients with heart failure from other causes were also studied. Functional correlations were also made for the natural killer cell subset. Total T-cell frequency, determined with antihuman T (Hybritech), was similar in IDC and control groups: mean 73 +/- 12% in IDC patients and 70 +/- 9% in control subjects. B-cell frequency, determined with antihuman Ia (Hybritech), was also similar: 36 +/- 11% in IDC patients and 31 +/- 10% in control subjects. Helper T-cell frequency, identified by OKT4 (Ortho), averaged 47 +/- 11% in IDC and 44 +/- 8% in control subjects (difference not significant). Suppressor/cytotoxic T-cell frequency, established by OKT8, was the same: 28 +/- 8% in IDC and 30 +/- 7% in control subjects, although relative deficiency in suppressor functional activity has been reported in IDC. Helper to suppressor (OKT4/8) ratios, aberrant in many autoimmune diseases, did not differ significantly (IDC 1.9 +/- 0.8, control 1.5 +/- 0.6). Lymphocyte subsets and OKT4/8 ratio were also similar between IDC and heart failure patients. Natural killer cell frequencies, estimated using 2 antibodies (antihuman Leu-7 and Leu-11, Becton-Dickinson) were the same (9.3 +/- 4.9% in IDC patients, 9.0 +/- 4.5% in control subjects, Leu-7).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗