Search PubMed⌕ Search

Biomedical subjects

B Alexander

Publications and source records attributed to B Alexander.

At least 145 records · Page 8Linked to original sources
PubMed1984

Practical miniaturized membrane oxygenator for isolated organ perfusion.

Silastic membrane tubing oxygenators possess valuable atraumatic properties, but no satisfactory miniature system for isolated organ perfusion has been achieved. We describe the construction of a new type of miniaturized Silastic membrane tubing oxygenator, 1.5 m long, 1.5-mm diameter, 75-micron wall thickness, incorporated in a single self-supporting unit readily applicable to isolated organ perfusion because of its simplicity, durability, and small prime volume of less than 3 ml. In vitro experiments using out-dated human banked blood demonstrated that the unit can effectively oxygenate blood of hematocrit 35% at flow rates of at least 10 ml/minute and that higher flow rates may be used to oxygenate blood or perfusates of a lower hematocrit. The results were verified in three different practical experimental applications: isolated rat liver, rabbit heart, and rat free skin flap perfusion.

Animals↗
PubMed1983

Prolonged partial cardiopulmonary bypass in rats.

Membrane oxygenators have been shown to be atraumatic during cardiopulmonary bypass. A novel design for a membrane tubing oxygenator originated in this laboratory was used for prolonged partial supportive cardiopulmonary bypass in lambs and displayed excellent biocompatability characteristics. This was miniaturized, to result in a prime volume of 12 ml, in order to investigate the feasibility of prolonged partial supportive cardiopulmonary bypass in rats. The performance of this miniaturized circuit over perfusion periods up to 6 hr is described, with particular reference to hematological changes.

Animals↗
PubMed1983

The impact of psychopharmacology education on prescribing practices.

The authors describe a pharmacology education program on the psychiatry service of a Veterans Administration medical center. The program, directed by a clinical pharmacist, includes weekly lectures to medical students and weekly psychopharmacology review rounds for psychiatric residents that are also attended by staff psychiatrists. To determine the impact of the psychopharmacology review rounds on prescribing practices, the authors conducted a retrospective chart review of psychopharmacologic treatment methods before and after the rounds were instituted. The review compared prescribing practices in the two periods and focused particularly on changes in practices related to multiple daily dosages, polypharmacy, prophylactic anticholinergics, and drug use in alcohol withdrawal. The review demonstrated that the teaching effort resulted in a use of psychotropic medications that was more in line with recommendations in the literature.

Adult↗
PubMed1983

Purification, characterization, and serologic characteristics of Bacteroides nodosus pili and use of a purified pili vaccine in sheep.

Hair-like appendages (pili) were isolated and purified from Bacteroides nodosus, the etiologic agent of foot rot disease in sheep. Microscopic and biochemical analyses indicated that pili from organisms isolated in Australia, New Zealand, and the United States are morphologically and structurally similar. Pili are filamentous assemblies of identical protein subunits. Using specific antisera raised in rabbits against pili, 7 antigenic types were identified. A geographic pattern in the distribution of the pilus serotypes was not evident. In a preliminary vaccine trial, sheep vaccinated with purified pili developed resistance to challenge exposure to B nodosus. Protection was correlated positively with the serum anti-pilus antibody titers.

Amino Acids↗
PubMed1983

Prediction of lithium maintenance doses using a single point prediction protocol.

Conflicting reports regarding the utility of a previously described single point prediction dosing method for lithium prompted the present study's reexamination of the relationship between a single point lithium concentration and the lithium maintenance dose. Seventeen informed, adult patients with affective illness were studied. The relationship between their 24-hour lithium concentration after a test dose and the maintenance dose was significant, hence confirming earlier reports. In addition, more confident relationships were noted when steady state range concentrations for lithium prophylaxis (0.41 to 0.89 mEq/liter) and for treatment of acute mania (0.9 to 1.27 mEq/liter) were analyzed separately. Maintenance dose predictive equations were generated for these lithium steady state ranges from a 24-hour single point level after a 1200-mg test dose. The clinical usefulness of the new relationships observed for maintenance dose prediction must await prospective testing.

Adult↗
PubMed1982

Therapeutic use of albumin: 2.

It has previously been shown that albumin costs in a Veterans Administration Hospital constituted a large portion of the pharmacy drug budget and that much albumin was prescribed inappropriately. Therefore, a program of education and use monitoring was instituted to improve understanding and prescribing of this product. Inappropriate use declined from 41% to 26% of total albumin units and, more dramatically, total cost of albumin used had decreased by 90% one year after this program was initiated. Projected yearly savings from decreased use was more than $85,000. These results demonstrate that such a program can promote more appropriate use of albumin and effect a cost savings for hospitals.

Albumins↗
PubMed1982

Evaluation of a chemical technique for determining the oxygen permeability of synthetic membranes.

The biocompatibility and high gas transfer characteristics of gas-permeable membranes have led to their use for total and supportive cardiopulmonary bypass. The gas transfer rates, particularly of oxygen, have previously been measured with sophisticated apparatus and this has restricted accurate measurements to a few laboratories. A simple chemical technique for measuring the oxygen permeability of synthetic membranes is described, in which sodium hydrosulfite is used to provide the highest possible oxygen gradient and the volume of oxygen crossing the membrane is measured volumetrically. Results agreed with those obtained with orthodox apparatus and replacement of the reducing agent with blood gave much lower oxygen transfer rates demonstrating the rheological influences of the blood upon oxygen transfer.

Blood Gas Analysis↗
PubMed1982

Temazepam (Restoril, Sandoz Pharmaceuticals).

Temazepam is a benzodiazepine derivative indicated for the treatment of insomnia. Pharmacokinetic studies of the hard capsule formulation indicate that the mean time to peak is 2.99 hours and the mean elimination half-life is 14.7 hours. Sleep laboratory studies have demonstrated improvements in all sleep parameters except sleep onset latency. Clinically, patients report improvements in all sleep parameters including sleep onset latency. The efficacy of temazepam compares favorably with barbiturates, glutethimide, nitrazepam, lorazepam, oxazepam, and flurazepam. It has not been compared with diazepam in the clinical setting. Side effects include drowsiness, dizziness, and lethargy. The incidence of hangover effects from 15- and 30-mg doses is relatively low. Temazepam has no proven advantages over other benzodiazepine hypnotics. The major issues that need further clarification include temazepam's sleep induction properties and the relative incidence of hangover and rebound insomnia when compared with longer-acting benzodiazepines.

Animals↗
PubMed1981

Mathematical analysis of a phenytoin--disulfiram interaction.

A case of phenytoin-disulfiram drug interaction is analyzed with a mathematical technique used in enzyme kinetics. Serum anticonvulsant levels, obtained before, during, and after disulfiram administration, were collected from hospital records retrospectively. Phenytoin kinetic constants--maximal velocity of metabolism (Vmax) and Michaelis-Menten constant (km)--before, during, and after disulfiram administration, were compared. The slopes (km) of the regression lines analyzed by a small sample t test for parallelism were not significantly different (p greater than 0.05). Y-intercept (Vmax) values obtained before (433 mg/day) and after (463 mg/day) disulfiram are both significantly different when compared with the y-intercept during (264 mg/day) disulfiram administration, by a small-sample t test for common intercept (p less than 0.05). Changes in the elimination rate of phenytoin or changes in y-intercept result from noncompetitive drug effects. It is concluded that disulfiram affects phenytoin's elimination rate by noncompetitive mechanisms.

Disulfiram↗
PubMed1981

Taking the sexual history.

Sexual concerns are commonly presented to family physicians in the course of routine care. Familiarity with issues central to most sexual concerns can facilitate history taking and appropriate treatment or referral for treatment. Physician requisites include comfort in discussing sexual issues directly, tolerance of value differences in patients and a working knowledge of various treatment options.

Communication↗