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Biomedical subjects

A Anderson

Publications and source records attributed to A Anderson.

At least 271 records · Page 15Linked to original sources
PubMed1982

Transplantation of islets and bone marrow cells to animals with immune insulitis.

The results of islet transplantation in an animal model of spontaneous immune insulitis were studied to see whether this disease process might damage transplanted tissue. Since the insulitis occurs only in "BB" rats (which are not genetically uniform) syngeneic grafts could not be used, therefore allograft rejection was avoided by rendering "BB" rats tolerant of WF transplantation antigens by inoculating them neonatally with WF bone marrow cells. Despite the resultant tolerant state, which permitted successful engraftment of WF skin and islets transplanted to artificially diabetic "BB" rats, tolerant "BB" rats with spontaneous diabetes accepted transplanted WF islets only briefly before they were destroyed by immune insulitis. "BB" rats were found to have abnormalities in immune response (delayed skin graft rejection and decreased alloreactivity in mixed lymphocyte response). "BB" rats that were treated neonatally with WF bone marrow. Moreover, "BB" rats inoculated with WF bone marrow neonatally were found less likely to become diabetic than untreated "BB" controls. It is suggested that the chimeric state (persistence of WF bone marrow cells) may be responsible for the improved immune response and perhaps for the decreased susceptibility to diabetes.

Animals↗
PubMed1981

Analysis of the anti-coccidial drug, halofuginone, in chicken tissue and chicken feed using high-performance liquid chromatography.

Methods are described for the analysis of the anti-coccidial drug, halofuginone, in chicken tissue at concentrations as low as 1 ppb (0.001 ppm) and in chicken feed at a concentration of 3 ppm, using high-performance liquid chromatography. The tissue analysis involves: enzymatic release of the halofuginone followed by ethyl acetate extraction under basic conditions, partition into ammonium acetate buffer, concentration using Sep-pakTM C18 cartridge. The feed analysis involves: ethyl acetate extraction under basic conditions, partition into hydrochloric acid, concentration using XAD-2 column chromatography. Both methods use high-performance liquid chromatography with ultraviolet detection for the final analysis. Precision and accuracy data for both methods are given.

Animal Feed↗
PubMed1981

High-performance liquid chromatographic analysis of captopril in plasma.

A sensitive assay is described for quantitating plasma captopril levels. Captopril is an orally active inhibitor of angiotensin-converting enzyme. Blood from patients taking this drug was collected into tubes containing edetate and ascorbic acid, and the plasma was separated by centrifugation. After addition of an internal standard, the plasma was deproteinized and the supernate was adjusted to pH 6.5 N-(1-Pyrene)-maleimide was added to derivatize captopril and an internal standard to fluorescent adducts. These derivatives then were extracted into ethyl acetate-benzene (1:1) and separated from other derivatized thiols by high-performance liquid chromatography. The sensitivity of the assay was 150 pmoles/ml. Preliminary pharmacokinetics were obtained in patients taking captopril chronically for essential hypertension. After administration of 100 mg of captopril for patients who had fasted overnight, the plasma levels rose rapidly; peak levels were obtained at approximately 37 min. Thereafter, the plasma levels declined rapidly, and the terminal half-life was approximately 40 min. In these patients, the time course of the plasma levels did not reflect changes in blood pressure, so there appeared to be no direct relationship between plasma levels of the parent compound and blood pressure changes.

Captopril↗
PubMed1981

Pharmacokinetics of the H2- receptor antagonist ranitidine in man.

1 Ranitidine pharmacokinetics were studied in six healthy volunteers. Following an overnight fast, doses of 20 mg intravenously 20, 40 and 100 mg orally and 100 mg orally with a standard meal, were administered to each subject on separate occasions. 2 Following intravenous administration there was a bioexponential decline in plasma levels from 576 +/- 56 ng/ml at 4 min to 10 +/- 2 ng/ml at 8 h. The distribution half-life (T 1/2 alpha) was 6.1 +/- 0.9 min, elimination half-life (T 1/2 beta) was 1.9 +/- 0.1 h, the volume of distribution (Vd beta) was 115 +/- 7 l and systemic plasma clearance (Cltp) was 709 +/- 62 ml/min. 3 Following 20 mg oral doses, peak levels were reached at 1.6 +/- 0.2 h and the systemic availability was 88 +/- 10%. Elimination half-life (T 1/2 beta) was unaffected by dose and the area under the curve increased linearly with dose and was unaffected by food. 4 Renal excretion (24 h) of unmetabolized ranitidine accounted for 50-70% of the dose with a further 1-3% appearing as desmethyl ranitidine.

Adult↗
PubMed1981

Types of paradoxical intervention and indications/contraindications for use in clinical practice.

A review of theoretical mechanisms underlying paradoxical interventions is undertaken in an effort to classify them into three broad types: redefinition, symptom escalation and crisis induction, and redirection. A list of individual and family patient characteristics and problems particularly applicable to each type of paradoxical intervention is presented along with contraindications for use. Last, implications for training and cautions as to their use are presented.

Adolescent↗
PubMed1981

Pharmacokinetic and gastric secretory studies of ranitidine in man.

A sensitive and specific high pressure liquid chromatographic procedure for ranitidine estimation is described and pharmacokinetic studies in six healthy volunteers reported. Each subjects received 20 mg of ranitidine i.v.; 20 mg, 40 mg and 100 mg orally having fasted overnight and 100 mg with a standard meal. Following the i.v. dose, ranitidine plasma concentrations fell biexponentially with a distribution half-life of 6.1 +/- 0.9 min and a terminal elimination half-life of 1.9 +/- 0.1 h. The volume of distribution was 115 +/- 7 1 and the systemic plasma clearance 709 +/- 62 ml/min. After 20 mg oral doses the systemic availability was high (88 +/- 10%). Bioavailability was unaffected by food and AUC increased linearly with dose to 100 mg. Renal excretion of unchanged ranitidine was between 50 and 70% and a further 1-3% was excreted as desmethylranitidine. In separate studies, the inhibitory action of cimetidine and ranitidine on pentagastrin stimulated gastric acid output was compared in seven duodenal ulcer patients. Results so far indicate that ranitidine 150 mg i.v. produces a more pronounced and more prolonged suppression of pentagastrin stimulated gastric acid output than cimetidine 200 mg i.v. (p less than 0.001). Ranitidine produced a sustained near total (greater than 90%) suppression in acid output in the period 60 to 120 min after drug administration, whereas acid output with cimetidine was less and fell from 82 to 54% in the same period.

Administration, Oral↗
PubMed1980

Kupffer cell phagocytosis in relation to BSP clearance in liver and inflammatory bowel diseases.

Experience using microaggregated human serum albumin for a Kupffer cell phagocytic capacity "stress test" in patients with liver and inflammatory bowel diseases is described. Each result has been related to a 1-hr BSP clearance in order to account for variations in liver blood flow. Kupffer cell clearances are reduced in proportion to BSP clearance in obstructive jaundice and in secondary biliary cirrhosis but are increased in patients with chronic hepatocellular inflmmation. Conversely Kupffer cell phagocytosis is often depressed in patients with alcoholic hepatitis. In Crohn's disease or ulcerative colitis RES function is normal unless patients are receiving corticosteroid suppression.

Colitis, Ulcerative↗
PubMed1980

Pseudobacteremia caused by Clostridium sordellii.

Thirteen of 280 (4.6%) blood cultures collected over a 12-day period were positive for Clostridium sordellii, a spore-forming anaerobe, rarely considered a human pathogen. Nosocomial bacteremia and intrinsic contamination of material used to culture blood were excluded as the source of the organism. Contaminated tincture of thimerosal used to swab the rubber stoppers of blood culture bottles prior to venting (aerobic) or during blind subculturing after 24 hours of incubation (anaerobic) in the clinical microbiology laboratory was determined to be the cause of the pseudobacteremia. After appropriate safe-guards were implemented, we have continued to use tincture of thimerosal for these procedures with no further growth of C sordellii from blood cultures. The importance of less-conspicuous steps in the routine processing of culture material have been reemphasized.

Blood Specimen Collection↗
PubMed1980

A technique developed for isolated canine papillary muscle function in various plasmas; and utility ascertained with plasma containing myocardial depressant factors.

Isolated papillary muscles from young dogs were studied to determine the feasibility of utilizing plasma, without added foam depressants, as a test solution to support muscle function. Diluted canine plasma, undiluted canine plasma, plasma with adjusted protein content, monkey plasma, and plasma containing myocardial depressant factors (MDF) were evaluated. For each test, each papillary muscle served as its own control, with either Krebs-Henseleit solution or a control plasma to establish a basis for evaluation of the test plasma. A technique was implemented to oxygenate the muscle, in plasma, without foam production and to monitor pH continuously. These studies indicated that plasma (diluted, undiluted, or with protein adjustments to accommodate experimental procedural requirements) was a satisfactory test solution. Furthermore, plasma from species unrelated to the dog could be utilized. In utilizing plasma, it was essential to establish or adjust the pH and osmolarity for normal muscle function. These studies with plasma containing MDF indicated that MDF depressed canine papillary muscle function. The Vmax values and Po values were decreased and latency was increased. The effects of MDF in canine papillary muscle preparations were completely reversible in short-term studies (up 10 10 hours' duration).

Animals↗