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Biomedical subjects

B Riley

Publications and source records attributed to B Riley.

27 records · Page 2Linked to original sources
PubMed1990

Effects of molecular oxygen, oxidation-reduction potential, and antioxidants upon in vitro replication of Treponema pallidum subsp. pallidum.

The effects of various concentrations of dithiothreitol, molecular oxygen, and several antioxidants upon the in vitro replication of Treponema pallidum were studied. The optimal dithiothreitol concentration was between 0.65 and 1.62 mM, and the optimum oxygen concentration was 3.0% +/- 0.5% in both the presence and absence of additional antioxidants. It was discovered that the reduced sulfhydryl concentration and the oxidation-reduction potential of the medium were stabilized after 5 days. The water-soluble antioxidants cobalt chloride, cocarboxylase, mannitol, and histidine were individually tested for their ability to increase treponemal growth in vitro. The optimum concentrations for these antioxidants were 21 nM, 4.3 nM, 0.55 mM, and 0.23 mM, respectively. When combined at these concentrations, the mixture of antioxidants stimulated the in vitro replication of T. pallidum. The number of treponemes in cultures with the antioxidants averaged a 59-fold increase, compared with a 43-fold increase in cultures lacking the antioxidants. It was further demonstrated that histidine and mannitol were the most critical components of this mixture. Catalase and superoxide dismutase were investigated for their ability to promote the growth and maintain viability of T. pallidum in tissue culture. The optimum concentrations for these enzymes were 10,000 U/liter and 25,000 U/liter, respectively. When these enzymes and the above antioxidants were combined and added to a chemically reduced modified Eagle medium, the treponemes increased an average of 70-fold, compared with an average of 35-fold in cultures lacking them. Furthermore, this medium, T. pallidum culture medium, supported the replication of T. pallidum at oxygen concentrations from 5 to 7% with little loss in yield or viability. The lipid-soluble antioxidants vitamin A and vitamin E acetate were also shown to enhance the in vitro growth of T. pallidum in this medium.

Antioxidants↗
PubMed1988

Continuous arteriovenous haemodialysis in critically ill patients.

Continuous arteriovenous haemodialysis (CAVHD) is a new treatment for critically ill patients with renal failure that combines convective and diffusive solute removal. The clearance of urea (14.8-22.1 ml/min) is sufficient to achieve a steady-state urea concentration of 22 mmol/l, even in patients with a high catabolic rate and cardiovascular instability. The technique is simple and does not involve the use of blood pumps or specialised staff. Initial experience in 36 critically ill patients with renal failure indicates that it is safe and reliable, with less associated morbidity than other techniques.

Acute Kidney Injury↗
PubMed1983

Mechanical ventilation with air-oxygen mixtures during total intravenous anaesthesia. An evaluation of the Penlon Nuffield Series 400 ventilator.

Mechanical ventilation with air-oxygen mixtures during total intravenous anaesthesia is discussed with the associated problem of obtaining a medically suitable source of air in British rooms. Independently powered ventilators capable of entraining filtered room air were thought to be the best solution. The Penlon Nuffield Series 400 ventilator was modified and assessed for use in this mode. An entrainment adapter and circuit was devised which allowed the ventilator to entrain more than sufficient ambient air, premixed with added oxygen for patient ventilation even under adverse conditions. The entrainment system ensured good mixing of the entrained air and oxygen and allowed accurate determination of oxygen concentration in the patient system using a suitable nomogram and without an oxygen analyser. An assessment of one-way patient valves was also undertaken. The Laerdal valve was found to be the most suitable for use with the system described.

Air↗
PubMed1980

Bioavailability and pharmacokinetics of a new, slow-release potassium chloride capsule.

The bioavailability of a new, slow-release potassium chloride product consisting of coated beads in a hard gelatin capsule was compared with the bioavailability of two marketed products, an elixir and a slow-release tablet, by determining the urinary excretion of potassium. Twelve healthy male volunteers were dosed with a total of 80 mEq of potassium, in a single dose for the capsule and tablet and in three 26.6-mEq doses at 6-hr intervals for the elixir. Mean recoveries in 24-hr urine potassium levels from all three dosage forms after subtracting normal urine potassium excretion levels were 50.8% from the capsule, 53.9% from the elixir, and 63.1% from the tablet. Maximum excretion rates were reached at 2.0 hr for the elixir, 6.8 hr for the capsule, and 4.0 hr for the tablet. Fewer side effects were reported with the capsule than with the elixir and tablet.

Adult↗
PubMed1977

Papaverine hydrochloride: the evaluation of two new dosage forms.

The bioavailability of papaverine, administered as sustained release capsules, an elixir, and soft gelatin capsules, was studied with volunteers. Blood samples were assayed for papaverine, using a gas chromatographic method, following the administration of single 150 mg doses of papaverine HC1. The elixir and the soft gelatin capsule resulted in nearly identical papaverine blood levels, while peak levels, area under the blood level-time curve, and plasma levels 0.5, 1.0, 1.5, and 2.0 hours after dosing with the sustained release capsule were significantly (p less than 0.01) lower.

Administration, Oral↗
PubMedDate not supplied

Assessment of clinical decision-making ability of critical care nurses.

What are nurse administrators to do when their institution is in need of competent nurses to staff the ICU and the majority of applicants are either inexperienced or new graduates? Nurses from one institution grappled with this question. They decided that it was their job to teach novice nurses to make sound clinical judgments in life-threatening situations. As part of this process, they developed a Clinical Decision-Making Assessment (CDMA) tool. This article describes the CDMA and provides suggestions for classroom and clinical teaching.

Adult↗
PubMedDate not supplied

Intrapartum care of a woman with aortic aneurysms.

Advances in technology and complex care have enabled women with various health problems to become and remain pregnant. Consequently, health-care practitioners are seeing an increasing number of pregnant women who have aortic aneurysms. This case study describes the culturally sensitive intrapartum care of a Middle Eastern woman with ascending and descending aortic aneurysms.

Aorta, Abdominal↗