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Biomedical subjects

B A Robinson

Publications and source records attributed to B A Robinson.

At least 55 records · Page 3Linked to original sources
PubMed1985

Comparison of the FeKal CON-Trate system with the formalin-ethyl acetate technique for detection of intestinal parasites.

The ability of the FeKal CON-Trate system (Trend Scientific, Minneapolis, Minn.) to recover parasite ova, cysts, or larvae from 300 fecal specimens was compared with that of the Formalin-ethyl acetate sedimentation technique. One hundred stool samples had previously been determined to contain 129 parasite forms. The FeKal system detected 127 parasites (sensitivity, 98.4%), and the Formalin-ethyl acetate sedimentation technique detected 125 parasites (sensitivity, 96.9%). Higher counts of parasite forms were obtained for 11 of 14 species of parasites in specimens prepared by the FeKal system. Four specimens were negative by the Formalin-ethyl acetate method and two by the FeKal system. These false-negative observations occurred in specimens with low counts of parasites. There were no false-positive results.

Acetates↗
PubMed1985

Carboplatin: a very active new cisplatin analog in the treatment of small cell lung cancer.

Carboplatin, a cisplatin analog without significant clinical nephrotoxicity, has been evaluated in the treatment of 56 patients with small cell lung carcinoma at a dose of 300-400 mg/m2 iv monthly in a phase II study. Twenty-three patients (41%) achieved a response, including five (9%) complete remissions. Of 30 previously untreated patients, 18 (60%) achieved a response, including three (10%) complete remissions. Median response duration was 4.5 months (range, 2-9). No nephrotoxicity was seen and hydration was not required. Nausea or vomiting occurred in only 24 patients (43%) and was rarely severe. Myelosuppression was dose-limiting: 20 patients (36%) developed leukopenia and eight (14%) developed thrombocytopenia, but leukopenic infections occurred in only three patients. Carboplatin is a very active new agent in the treatment of small cell lung cancer, with less toxicity and better tolerance than cisplatin. It merits further investigation in combination chemotherapy and against non-small cell lung cancer.

Adult↗
PubMed1985

Enzymatic correction of interference in the kinetic Jaffé reaction for determining creatinine in plasma.

We evaluated a simple, specific method for measuring plasma creatinine concentration, involving enzymatic degradation of creatinine before analysis by a kinetic Jaffé reaction. The enzymes--prepared in a dry, stable form--are convenient to use and eliminate the need to correct for sample dilution. As little as 50 microL of plasma is required, making the procedure ideal for use with samples from children. Between-day precision studies for determination of plasma creatinine at concentrations of 70 and 470 mumol/L yielded CVs of 7.8 and 4.3%, respectively. Analytical recovery of creatinine added to plasma samples ranged from 94 to 113%. Linear regression analysis demonstrated excellent agreement between results by this method and those by a "high performance" liquid-chromatographic technique.

Amidohydrolases↗
PubMed1983

Serum profiles and safety of intermediate-dose (500-1,000 mg) methotrexate following IV and IM administration.

Despite extensive clinical experience with methotrexate there is no consensus of opinion as to the ideal method of administration. This study tested the hypotheses that intermediate-dose (500-1,000 mg) methotrexate can safely by administered to outpatients as an IM injection, and that similar serum profiles of methotrexate result from IM and IV administration. Fourteen patients received 500 mg methotrexate, and nine of these received 1,000 mg as an IM injection. Methotrexate levels at 24 and 48 h were below the levels at which toxicity can be expected. Six patients received 500 mg both IM and IV and 1,000 mg both IM and IV. Serum methotrexate profiles over 48 h were similar following both IM and IV administration. This study showed no evidence of significant toxicity in terms of bone marrow, gastrointestinal, or renal impairment.

Adult↗
PubMed1983

Liquid-chromatographic determination of aminoglutethimide in plasma.

A simple, rapid "high-performance" liquid-chromatographic procedure is presented for the determination of aminoglutethimide in plasma. After precipitation of the protein with acetonitrile, an aliquot of the supernate is injected directly onto a radially compressed, reversed-phase column. The aminoglutethimide is isocratically eluted with a mobile phase of acetonitrile/water/tert-butyl ammonium phosphate. The method is both accurate and precise and has been in routine use in our laboratory for more than 12 months.

Aminoglutethimide↗
PubMed1980

Evaluation of xylazine in camels.

When xylazine was given intramuscularly to 12 apparently healthy adult camels (Camelus dromedarius) at the rate of 0.4 mg/kg of body weight, mean values for onset of weak time, down time, and time until recovery were 8.6 +/- 1.1, 10.5 +/- 0.6, and 150 +/- 56.9 minutes, respectively. Mild salivation, drooping of lower lips, and relaxation of neck were observed at meant times of 15.3 +/- 4.9, 11.0 +/- 1.7, and 22.7 +/- 3.9 minutes, respectively. Analgesic effects remained for 60 to 90 minutes. Hemocytologic changes were not statistically significant. Marked hyperglycemia was observed at 30 minutes after xylazine administration. Hypotension from 30 to 60 minutes after xylazine administration was not correlated with elevated central venous pressure or with bradycardia. Electrocardiography revealed 1st-degree atrioventricular block, sinoatrial block, sinus arrhythmia, and wandering pacemaker in sinoatrial node, which were attributed to vagal stimulation. Primary T-wave changes and ST segment elevation also were observed. When xylazine was used at the same dosage in 13 clinical cases involving surgery of short duration, it proved to be a satisfactory sedative, analgesic, and muscle relaxant.

Analgesia↗
PubMed1976

Relationships between serosal medium potassium concentration and sodium transport in toad urinary bladder. I. Effects of different medium potassium concentrations on electrical parameters.

When serosal medium potassium was decreased from the usual concentration of 3.5 mM, the short-circuit current (SCC) of hemibladders in chambers immediately and transiently increased. The maximum SCC attained was greater the greater the decrease in serosal potassium, and was twice the initial SCC when the final serosal medium was potassium-free. The SCC then fell to its previous level for final serosal potassium concentrations greater than 2 mM and to less than its previous level for those less than 2 mM, being lowest (15% of previous levle) in potassium-free sodium Ringer's. When serosal medium potassium was increased from 3.5 mM by substituting potassium for sodium, SCC transiently decreased and then recovered to its previous level. Steady SCC was the same in serosal media of 2-116 mM potassium; conductance increased and p.d. decreased after incubation in 50-116 mM potassium serosal media. Short-circuit current and p.d. transiently increased (decreased) whenever serosal medium potassium was decreased (increased); conductance increased with any change in serosal potassium. Changing mucosal medium potassium concentration between 0 and 50 mM did not affect SCC. The initial transient increase and subsequent decrease in SCC on removing serosal potassium were partially prevented by 3.5 mM rubidium or caesium, or by 116 mM choline in the serosal medium. The transient changes in SCC were due partly to changes in transepithelial sodium transport.

Animals↗
PubMed1976

Relationships between serosal medium potassium concentration and sodium transport in toad urinary bladder. II. Effects of different medium potassium concentrations on epithelial cell composition.

Epithelial cells from hemibladders incubated in potassium-free sodium Ringer's serosal medium lost potassium, both in exchange for serosal sodium and with chloride and water. Cellular sodium of mucosal origin did not change. The loss of cellular potassium, chloride and water closely followed the fall in short-circuit current (SCC). One third as much potassium, chloride and water were lost in 1 mM potassium serosal medium; SCC fell 1/3 as much. Potassium-free choline Ringer's serosal medium abolished the initial increase in SCC and reduced the fall in cellular potassiu, chloride and water and in SCC. Ouabain (10(-2)M) in potassium-free medium prevented the initial increase in SCC and the loss of cellular chloride and water. Ouabain (5 X 10(-4)M) caused loss of cellular potassium in exchange for mucosal and serosal sodium, effects different from those of absence of serosal potassium although SCC was similarly inhibited. Sodium-free mucosal medium abolished SCC and prevented the initial transient of SCC and diminished loss of cellular potassium, chloride and water on removing serosal potassium. When serosal potassium concentration was increased considerably, cells gained potassium, chloride and water, and in 116 mM potassium media, lost sodium of serosal origin. A hypothesis is advanced to explain the transients in SCC on changing serosal potassium concentration. The fall in cellular potassium, not water, probably inhibits sodium transport in media of less than 2 mM potassium.

Animals↗
PubMed1976

Relationships between serosal medium potassium concentration and sodium transport in toad urinary bladder. III. Exchangeability of epithelial cellular potassium.

The exchangeability of toad bladder epithelial cell potassium has been investigated. An insignificant amount of cellular potassium exchanged with mucosal medium 42K. From the rate of uptake of 42K into the cells from the serosal medium at least two cellular potassium pools were identified. The more rapidly exchanging pool contained about one-quarter to one-third of the cellular potassium and exchanged with a half-time of about 30 min. It was from this pool that potassium was lost from cells exposed to ouabain or to a potassium-free medium. In addition, when 3.5 mM rubidium replaced 3.5 mM potassium in sodium Ringer's the epithelial cells lost in 60 min about one-quarter of their cellular potassium in exchange for rubidium. Inhibition of transepithelial sodium transport by amiloride, 10(-5) mM, seemed to depress the rate of potassium uptake into the more rapidly exchanging pool without affecting total cellular potassium content. However, stimulation of transepithelial sodium transport by vasopressin appeared not to affect the rate of potassium uptake. The rate of potassium uptake into this pool seemed much less than that required for a tight 1:1 coupling between transepithelial sodium transport and potassium uptake. The remaining cellular potassium exchanged at a much slower rate and even after 19 hours of incubation only 67% of cellular potassium was labelled. If this slower exchanging potassium represents a single pool, 99% of cellular potassium would be labelled only after incubation with 42K for 56 hours.

Animals↗
PubMed1975

Metabolic studies of [75Se]selenocystine and [75Se]selenomethionine in the rat.

1. The long-term fate in rats of an oral dose of [75Se]selenocystine was compared with that of an oral dose of [75Se]selenomethionine. 2. Urinary and faecal radioactivities were measured during the 1st week and whole-body radioactivity was determined for 10 weeks. Rats were killed at weekly intervals for 4 weeks and at weeks 6 and 10 for analysis of tissue distribution of 75Se. 3. Intestinal absorption of [75Se]selenocystine was 81% of the administered dose; that of [75Se]selenomethionine was 86%. Urinary excretion of absorbed [75Se]selenocystine was 13-9% and that of [75Se]selenomethionine was 5-8% in the 1st week. 4. Whole-body retention of 75Se was greater for [75Se]selenomethionine than for [75Se]selenocystine but after the 1st week it decreased at a similar rate in both groups. Tissue distribution of retained 75Se was also similar in both groups. 5. The initial utilization of [75Se]selenocystine was different from that of [75Se]selenomethionine. However, after the 1st week 75Se from both sources appeared to be metabolized similarly, suggesting that dietary Se of both forms is ultimately incorporated into the same metabolic pool. 6. When these findings were compared with those of earlier studies with [75Se]selenite and 75Se incorporated in vivo into rabbit kidney (RK-64Se) (Thomson, Stewart & Robinson, 1975) the metabolism of [75Se]selenocystine resembled that of [75Se]selenite and RK-75Se, rather than that of [75Se]selenomethionine.

Amino Acids, Sulfur↗
PubMed1974

The regulation of cellular volume in liver slices.

1. Rat, rabbit and guinea-pig liver slices were incubated in media at 37 degrees C to study effects of ouabain and of metabolic inhibition on tissue composition.2. Slices initially incubated in oxygenated balanced medium did not swell when exposed to either balanced media or potassium-free media containing ouabain in concentrations ranging from 0.1 to 10 mM though they lost potassium and gained a comparable amount of sodium.3. Without prior incubation in oxygenated medium slices initially swelled when incubated with ouabain but then maintained their new volume.4. Slices whose metabolism was inhibited by incubation with nitrogen and 1 or 10 mM iodoacetamide lost as much potassium as slices exposed to 10 mM ouabain but became swollen with the uptake of sodium, chloride and water.5. The results show that liver cells, like renal cortical cells, possess a metabolically dependent, ouabain-insensitive, potassium-independent mechanism concerned in the regulation of cellular volume.

Acetamides↗
PubMedDate not supplied

A risk factor for relapse in Hodgkin's disease: female gender?

A retrospective study of 163 patients with Hodgkin's disease treated between 1969 and 1987 was performed to identify adverse prognostic factors. One hundred and thirty-five patients (83 per cent) attained a complete remission and 42 (31 per cent) of these have relapsed (median follow-up--43 months). Using multivariate analysis, no independent factors predicted for the event of relapse. However, analysis of disease-free survival revealed that females fared significantly worse than males (p less than 0.05) and this was independent of other prognostic variables. Female sex has not been recognized as an independent prognostic factor predictive of inferior survival and inferior disease-free survival.

Antineoplastic Agents↗
PubMedDate not supplied

The saturated zone at Yucca Mountain: an overview of the characterization and assessment of the saturated zone as a barrier to potential radionuclide migration.

The US Department of Energy is pursuing Yucca Mountain, Nevada, for the development of a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste, if the repository is able to meet applicable radiation protection standards established by the US Nuclear Regulatory Commission and the US Environmental Protection Agency (EPA). Effective performance of such a repository would rely on a number of natural and engineered barriers to isolate radioactive waste from the accessible environment. Groundwater beneath Yucca Mountain is the primary medium through which most radionuclides might move away from the potential repository. The saturated zone (SZ) system is expected to act as a natural barrier to this possible movement of radionuclides both by delaying their transport and by reducing their concentration before they reach the accessible environment. Information obtained from Yucca Mountain Site Characterization Project activities is used to estimate groundwater flow rates through the site-scale SZ flow and transport model area and to constrain general conceptual models of groundwater flow in the site-scale area. The site-scale conceptual model is a synthesis of what is known about flow and transport processes at the scale required for total system performance assessment of the site. This knowledge builds on and is consistent with knowledge that has accumulated at the regional scale but is more detailed because more data are available at the site-scale level. The mathematical basis of the site-scale model and the associated numerical approaches are designed to assist in quantifying the uncertainty in the permeability of rocks in the geologic framework model and to represent accurately the flow and transport processes included in the site-scale conceptual model. Confidence in the results of the mathematical model was obtained by comparing calculated to observed hydraulic heads, estimated to measured permeabilities, and lateral flow rates calculated by the site-scale model to those calculated by the regional-scale flow model. In addition, it was confirmed that the flow paths leaving the region of the potential repository are consistent with those inferred from gradients of measured head and those independently inferred from water-chemistry data. The general approach of the site-scale SZ flow and transport model analysis is to calculate unit breakthrough curves for radionuclides at the interface between the SZ and the biosphere using the three-dimensional site-scale SZ flow and transport model. Uncertainties are explicitly incorporated into the site-scale SZ flow and transport abstractions through key parameters and conceptual models.

Forecasting↗