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Biomedical subjects

J L Anderson

Publications and source records attributed to J L Anderson.

At least 361 records · Page 20Linked to original sources
PubMed1972

Model pores of molecular dimension. The preparation and characterization of track-etched membranes.

Extremely uniform pores of near molecular dimension can be formed by the irradiation-etching technique first demonstrated by Price and Walker. The technique has now been developed to the stage where it can be used to fabricate model membranes for examining the various steric, hydrodynamic, and electrodynamic phenomena encountered in transport through molecular-size pores. Methods for preparing and characterizing membranes with pores as small as 25 A (radius) are described in this paper. Results on pore size determination via Knudsen gas flow and electrolyte conduction are compared. Pore wall modification by monolayer deposition is also discussed.

Biological Transport↗
PubMed1971

Eggshell thinning in Japanese quail fed mercuric chloride.

The eggs produced by developing Japanese quail (Coturnix coturnix japonica) fed 1 to 8 parts of mercury per million as mercuric chloride for 10 weeks have thinned shells. Total amounts of mercury in tissues were quite proportional to the dosage and were higher in males than in females. Methylation of mercury was not observed.

Animals↗
PubMedDate not supplied

Disposition of intravenous pirmenol.

Twelve patients having frequent premature ventricular complexes (PVCs) averaging more than 60 per hour received a single 150-mg intravenous dose of pirmenol. Plasma pirmenol concentration declined biexponentially following the infusion and was analyzed according to a two-compartment open model. Following an erratic distribution phase, the terminal elimination half-life ranged from 4.2 to 16.9 hours, with a geometric mean of 7.6 hours. Total body clearance averaged 164 +/- 58 ml/min, and the mean volume of distribution was 1.45 +/- 0.38 liter/kg. Renal clearance averaged 46.6 +/- 21.2 ml/min, representing 30 +/- 10 per cent of total body clearance. Excretion of unchanged drug in the urine averaged 31.8 +/- 8 per cent of the dose. Renal clearance and elimination half-life were correlated (r = -0.61, P less than 0.05). Eight of the 12 patients achieved greater than 95 per cent suppression of PVCs with a duration between 20 minutes and 23 hours. These favorable pharmacokinetics indicate that pirmenol may be a useful addition to the therapy of ventricular arrhythmias.

Adult↗
PubMedDate not supplied

Flecainide: a new prototype antiarrhythmic agent.

Flecainide acetate is the first class IC antiarrhythmic agent marketed in the United States. In vitro, animal and human studies have shown that the drug markedly prolongs conduction and has minimal effect on repolarization. Efficacy trials have shown flecainide to be effective in a wide range of ventricular and selected atrial arrhythmias. The drug is generally well tolerated, although minor adverse effects are common. These generally are related to the central nervous system and respond to a reduction in dosage. Like other antiarrhythmic agents, flecainide may demonstrate proarrhythmic effects. It is excreted in the urine as the parent compound and inactive metabolites. The elimination half-life ranges from 12-27 hours in patients with normal renal function, allowing convenient dosing regimens of 100-200 mg twice daily in most patients. Flecainide has the potential for widespread use.

Administration, Oral↗
PubMedDate not supplied

Bethanidine sulfate in paroxysmal ventricular tachycardia: toxicity and antifibrillatory actions.

Programmed ventricular stimulation was used to test oral bethanidine sulfate in 10 patients with life-threatening ventricular arrhythmias. These patients had previously documented, recurrent, sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) complicating stable heart disease. During control electrophysiologic studies, VT could be induced in all 10 patients: 6 with nonsustained VT, 3 with sustained VT, and 1 with VT/VF. After control, bethanidine 20-30 mg/kg was administered orally and beginning 60 minutes later, programmed ventricular stimulation was repeated. After bethanidine administration, VT could be induced in nine patients; in four, the VT was essentially unchanged from that induced during control studies. In four others, worse VT was induced after bethanidine. The remaining two patients had a potentially beneficial response to the drug. Bethanidine was poorly tolerated: seven patients had symptomatic orthostatic hypotension that persisted for several days despite concurrent protriptyline therapy. Furthermore, in four patients, spontaneous VT or VT/VF occurred 3-8 hours after the last dose. Nausea, vomiting, flushing, and blood pressure elevation were also noted. Bethanidine sulfate in the dosages used usually does not prevent the induction of VT by programmed ventricular stimulation and frequently causes serious toxicity. These findings suggest that the drug would be ineffective and poorly tolerated for long-term therapy in patients with serious ventricular arrhythmias.

Administration, Oral↗
PubMedDate not supplied

Communicating with terminal cancer patients.

Communication between doctors and terminal cancer patients has been identified as a problem area in medical care. There have been attempts to overcome this problem by establishing new teaching programs; however, the most effective teaching methods are costly. A model is described that requires minimal staff involvement in teaching about communicating with terminal cancer patients.

Attitude to Death↗