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Biomedical subjects

C Forbes

Publications and source records attributed to C Forbes.

At least 19 recordsLinked to original sources
PubMed1994

Economic evaluation of standard heparin and enoxaparin for prophylaxis against deep vein thrombosis in elective hip surgery.

Deep vein thrombosis (DVT) is a common complication in patients undergoing elective hip surgery. Because of the associated risk of pulmonary embolism, prophylaxis with standard (unfractionated) heparin is becoming increasingly important. Recent clinical trials have shown a low molecular weight form of heparin, enoxaparin, to be more effective than standard heparin in preventing DVT, but the new drug is also more expensive. Data on clinical effectiveness and cost were combined in an economic evaluation of the two regimens. It was found that prophylaxis with enoxaparin would be expected to lead to a net saving of 20 pounds per patient. The economic results are sensitive to the costs of enoxaparin, the costs of drug administration and the probability of false clinical diagnosis of DVT or pulmonary embolism.

Decision Trees↗
PubMed1993

The effects of unilateral stellate ganglion blockade on human cardiac function during rest and exercise.

INTRODUCTION: Left-sided stellate ganglion predominance has been proposed as a mechanism responsible for lethal ventricular arrhythmias, due to heterogenous ventricular repolarization. To determine the cardiovascular effects of such asymmetric sympathetic ganglion innervation in man, studies were performed in 15 patients undergoing unilateral stellate ganglion blockade for the management of chronic arm pain. METHODS AND RESULTS: Standard 12-lead ECGs, systemic blood pressure, body surface potential mapping, and radionuclide angiography were performed during rest and graded exercise before and after blockade. Successful unilateral blockade was accomplished in 13 of the patients, 11 of whom had right-sided blockade and two left-sided blockade. No significant changes due to blockade of stellate ganglia, including QT intervals, were detected during rest or graded exercise in standard ECGs. No cardiac rhythm disturbances occurred in these states. Body surface potential maps and arterial blood pressure were similar during resting supine and upright positions, as well as immediately after exercise before and after blockade. Unilateral ganglionic blockade did not modify resting or exercise cardiac ejection fractions. CONCLUSION: Unilateral stellate blockade in man does not induce untoward cardiovascular effects during rest or exercise.

Adult↗
PubMed1991

The pharmacokinetics of dermatan sulphate MF701 in healthy human volunteers.

1. The pharmacokinetics of dermatan sulphate MF701 were studied in 12 healthy males after administration of single intravenous bolus (200 mg), intramuscular (100 and 300 mg) and oral (1 g) doses. The study was conducted according to a within-subject crossover design in two paired blocks. 2. Plasma drug concentrations were measured using a competitive binding assay and a range of biological activity assays, including a sensitive catalysed thrombin inhibition test. 3. Following intravenous administration, plasma concentrations of dermatan sulphate determined by competitive binding assay were described by a two-compartment open model with an initial t1/2, in of 0.6 h and a t1/2,z of 7.5 h. Biological activity assays were insufficiently sensitive to detect the second phase, and therefore yielded apparent monoexponential kinetics. 4. After intramuscular injection the apparent bioavailability of dermatan sulphate was 16-20%. Plasma drug concentrations increased in proportion to dose when measured by competitive binding assay. Low concentrations persisted for more than 24 h at the higher dose, and these may prove therapeutically relevant on chronic administration. 5. We confirm that dermatan sulphate is the only glycosaminoglycan known to generate significant plasma concentrations following oral administration. Oral bioavailability was estimated to be 7%.

Adolescent↗
PubMed1987

Characterization of an expanded large granular lymphocyte subset lacking natural killer activity present in renal allograft recipients.

We have previously reported that, in long-term renal allograft recipients who receive chronic chemical immunosuppression and who are at risk for late chronic viral infections and virus associated tumors, the percentage of lymphocytes the phenotype of which is Leu-7+/Leu-11(-) (CD16) is markedly and significantly increased compared with that in normal controls. Since this population may lack natural killer (NK) activity and may explain the state of decreased host resistance, we carried out studies in 16 kidney transplant recipients on conventional immunosuppression and 10 age-matched normal controls to further define the phenotype, the morphology, and the NK cell activity of this particular subset. Using two-color flow cytometry analysis we found that the Leu-7+ cell subset comprises two essentially nonoverlapping subpopulations, depending on whether cells are coexpressing the NK cell marker Leu-11/CD16 (Leu-7+/Leu-11+ phenotype) or the pan-T cell marker Leu-4/CD3 (Leu-7+/Leu-4+ phenotype). We thus demonstrated that Leu-7+/Leu-11- cells do coexpress the Leu-4+/CD3 surface determinant. The percentage of Leu-7+/Leu-4+ (CD3) is significantly elevated in transplant recipients compared with that in normal controls (26 +/- 4% versus 8 +/- 2%, P less than 0.005). In contrast, the size of the Leu-7+/Leu-11+ cell subset is similar in both groups. Although in transplant recipients 70% of Leu-7+ cells coexpress Leu-4/CD3, only 43% do so in the control group. Cell sorter experiments isolated the Leu-7+/Leu-4+ cells and showed that morphologically these cells are typical large granular lymphocytes that cannot be distinguished from Leu-11+ NK cells. NK-sensitive K562 target cells showed no cytotoxicity. In contrast, Leu-7+/Leu-11+ cells exhibited high killing activity. Therefore, in long-term stable renal allograft recipients at increased risk of developing cancers and chronic viral infections, a subpopulation of non-NK large granular lymphocytes, the phenotype of which is Leu-7+/Leu-11-/Leu-4+, is abnormally expanded. This subset likely contributes to the diminished functional attributes of the chronic drug-induced immunodeficiency.

Adult↗
PubMed1981

Sex-linked lethal frequencies produced by 7,12-dimethylbenz[a]anthracene in five Drosophila melanogaster wild strains.

7,12-Dimethylbenz[a]anthracene (DMBA) was tested for the induction of mutations in 5 strains of Drosophila melanogaster. Larvae were fed mixtures containing either 1.0 or 4.0 mM DMBA in darkness. After emergence the males were mated to Basc females to test for sex-linked lethals. Canton-S males produced the highest frequency with no significant differences in the induction of lethals by the 2 concentrations. DMBA was slightly mutagenic in Oregon-R males over controls without significant differences between the 2 concentrations. Berlin-K, Lausanne-S and Urbana-S males all produced significantly more mutations at the 4.0-mM than the 1.0-mM concentrations. DMVA produced partial sterility in Canton-S and Urbana-S males. The DMBA mutation frequencies of all 5 wild strains are interpreted as being related to the levels of activating enzymes that metabolize DMBA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Sex-linked lethal mutations induced in Drosophila melanogaster by 7,12-dimethylbenz[a]anthracene.

One of the most potent carcinogens, 7,12-dimethylbenz[a]anthracene (DMBA), was tested for the induction of mutations in 2 strains of Drosophila melanogaster. Larvae were fed mixtures containing DMBA, peanut oil and solubilizing agents in darkness. After emergence the males were mated with Basc or FM7a females to test for sex-linked lethals. For Canton-S males, all DMBA treatments produced highly significant increases in mutation frequencies over controls. DMBA was slightly mutagenic for Oregon-R males.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Self-perception of employed and unemployed haemophiliacs.

Semi-structured interviews concerning various aspects of mental health were carried out with 13 employed and 13 unemployed haemophiliacs 20-35 years old. Significant differences in patients' responses were related to their employment status and the degree of severity of haemophilia. Unemployed patients with milder forms of haemophilia appeared to be least adjusted and suffered most from psychosomatic symptoms.

Adult↗