PubMed Health⌕ Search

Biomedical subjects

D Farrar

Publications and source records attributed to D Farrar.

17 recordsLinked to original sources
PubMed2005

Volatile organic compounds in selected micro-environments.

A program of sampling for volatile organic compounds (VOCs) in ambient air was undertaken in selected locations and micro-environments in Perth, Western Australia to characterise concentrations of target VOCs and to determine the relative strength of the contributing sources to ambient air in different micro-environments in a major Australian city. Twenty-seven locations were sampled and, of the forty-one target compounds, 26 VOCs were detected in the samples collected. The highest concentrations were recorded for benzene, toluene, ethylbenzene, xylenes (BTEX), chloroform and styrene. The maximum 12-h toluene and benzene concentrations observed were from a basement carpark and were 24.7 parts per billion (ppb) and 5.6 ppb, respectively. The maximum xylenes concentration was 29.4 ppb and occurred in a nightclub where styrene was also detected. A factor analysis of the data was undertaken. Two key factors emerge that appear to be associated with petroleum and motor vehicles and environmental tobacco smoke. A third significant occurrence was a high concentration of chloroform that was observed at a sports centre complex with a swimming pool text and was uncorrelated with other compounds in the data set. This study indicates that locations associated with motor vehicles and petrol fuel, tobacco and wood smoke and chlorinated water represent the major risks for personal exposure to VOCs in Perth.

Air Pollutants↗
PubMed2004

Assessment of preoperative fluid depletion using bioimpedance analysis.

BACKGROUND: Fluid depletion during the perioperative period is associated with poorer outcome. Non-invasive measurement of total body water by bioimpedance may enable preoperative fluid depletion and its influence on perioperative outcome to be assessed. METHODS: Weight and foot bioimpedance were recorded under standardized conditions in patients undergoing bowel preparation (n=43) or day surgery (n=44). Fifteen volunteers also followed standard nil-by-mouth instructions on two separate occasions to assess the variabilities of weight and bioimpedance over time. RESULTS: Body weight fell by 1.27 kg (95% CI 1.03-1.50 kg; P<0.0001) and foot bioimpedance increased by 51 ohm after bowel preparation (95% CI 36-66; P<0.0001). Weight change after the nil-by-mouth period in day-surgery patients (mean -0.22 kg, 95% CI -0.05 to -0.47 kg; P=0.07) correlated (r=-0.46; P=0.005) with an increase in bioimpedance (16 ohms, 95% CI 5-27 ohms; P=0.01). No difference between two separate bioimpedance measurements was seen in the volunteer group. CONCLUSIONS: Further work is warranted to determine if bioimpedance changes may serve as a useful indicator of perioperative fluid depletion.

Adult↗
PubMed2004

Blood usage in an Australian intensive care unit: have we met best practice goals?

The transfusion of blood products, especially red cell concentrates, in critically ill patients is controversial and benefits of red cell concentrate transfusion in these patients have not been clearly demonstrated. We performed a prospective observational study to compare best evidence to actual practice of red cell concentrate and other blood product administration in an intensive care unit (ICU) in a university-associated tertiary hospital. All primary admissions during a 28-day period were included in the study and data collected included transfusion of red cells and blood products, patient demographics and ICU and hospital outcome. One hundred and seventy-five admissions were studied; 44% followed cardiac surgery. Forty-one patients (23%) received red cell concentrates in ICU, with 120 units transfused in 61 separate episodes. Other blood product usage was minimal. One third (20/61) of red cell concentrate transfusion episodes were of a single unit. The mean (+/- SD) pre-transfusion haemoglobin was 7.9 +/- 1.1 g/dl. Despite transfusion, such patients left ICU with a lower haemoglobin concentration compared with untransfused ICU patients (9.5 +/- 1.0 versus 10.5 +/- 2.1 g/dl; P < 0.001). Cardiac surgical patients received similar red cell transfusion to general ICU patients. Univariate analysis showed no significant difference in mortality between patients who did or did not receive red cell concentrate transfusion (P = 0.17). However, red cell concentrate transfusion was associated with a reduced adjusted mortality both in ICU (OR 0.13, 95% CI 0.02-0.73) and in hospital at 28 days (OR 0.10, 95% CI 0.02-0.58). The low red cell concentrate and blood product usage in our ICU were consistent with restrictive transfusion practice and selective red cell concentrate transfusion was associated with reduced mortality.

APACHE↗
PubMed2001

Medical repatriation via fixed-wing air ambulance: a review of patient characteristics and adverse events.

Anaesthetists are often employed as medical escorts for patients undergoing international transfer by air ambulance. There is little published data on the types of patients being transferred and on the incidence of adverse events. We performed a retrospective review of the documentation of all air ambulance transfers performed by a single company over a 2-year period followed by a prospective assessment of all high-risk patients transferred over a 1-year period. Of 483 transfers identified, 47% were defined as high-risk and 20% were of patients receiving mechanical ventilation. In the prospective group, 28% of patients required pretransfer optimisation, 7% required a major therapeutic intervention during transfer and there was a major adverse event in 12% of transfers. There were two deaths during transport. These data support the recommendation that escorting personnel should be from an appropriate speciality, have reasonable seniority and be adequately trained and supervised.

Adolescent↗
PubMed2001

Bell's palsy, childbirth and epidural analgesia.

We report a case of Bell's palsy following delivery in a parturient who had successful epidural analgesia. Most reported cases have occurred after spinal anaesthesia or inadvertent dural puncture complicating epidural analgesia. Review of the literature revealed few cases of Bell's palsy associated with uncomplicated epidural analgesia. In this report we discuss the controversy surrounding the aetiology and possible mechanism of onset of this unpleasant complication.

Journal Article↗
PubMed1991

Recombinant human stem cell factor, a c-kit ligand, stimulates hematopoiesis in primates.

Recombinant human stem cell factor (SCF) is homologous with recombinant rat SCF (rrSCF) and is a ligand for c-kit. We determined the influence of SCF on hematopoiesis in vitro and in vivo in baboons. In vitro, SCF alone stimulated little growth of hematopoietic colony-forming cells from baboon marrow, but did increase the number of colonies formed in response to erythropoietin (Epo), interleukin-3 (IL-3), and granulocyte-macrophage colony-stimulating factor (GM-CSF). In vivo, SCF caused an increase in the peripheral blood of the number of erythrocytes, neutrophils, lymphocytes, monocytes, eosinophils, and basophils. In marrow, it caused an increase in marrow cellularity and in the absolute number of colony-forming unit-granulocyte-monocyte (CFU-GM) and burst-forming unit-erythroid (BFU-E) in marrow following infusion of SCF. The in vivo stimulation of multiple lymphohematopoietic lineages corroborates previous in vitro studies and suggests a potentially important clinical role for SCF.

Animals↗
PubMed1990

Exact statistical tests for any carcinogenic effect in animal bioassays. II. Age-adjusted tests.

Statistical methods are discussed for application in animal carcinogenesis bioassays that test a general null hypothesis that response frequencies are independent of the treatment level for all tumor endpoints, sexes, and species considered in the bioassay, conditional on survival. These methods are similar to those proposed earlier by Farrar and Crump (1988, Fundam, Appl. Toxicol. 11, 652-663) which involve test statistics that are functions of p values from multiple standard statistical hypothesis tests, and evaluation of significance using randomization. Refinements include the introduction of an exact incidental tumor test analogous to the asymptotic test of Hoel and Walburg (1972, J. Natl. Cancer Inst. 49, 361-372), which takes into account the possibility that any differences among treatment groups in response rates result from differences in survival that is independent of tumors. Additional consideration is given to selection of test statistics, and a test is proposed that is sensitive specifically to cases where the same tumor endpoints are affected in multiple sexes and species. Applications of the procedures to results of National Toxicology Program (NTP) bioassays concerning decabromodiphenyl oxide and iodinated glycerol illustrate the sensitivity of tests based on different test statistics to distinct alternative hypotheses. When compared with the qualitative conclusions of the NTP regarding the strength of evidence for a carcinogenic effect in the same bioassays, the results presented suggest that the methods can be useful in clarifying otherwise equivocal evidence for carcinogenicity. Various difficulties are discussed relevant to the construction of exact combined fatal and incidental tumor tests analogous to the tests of Peto et al. (1980, IARC Monogr. Suppl. 2).

Age Factors↗
PubMed1990

Exercise as a treatment for hypertension in low-socioeconomic-status black children.

Low-socioeconomic-status (SES) Black children have a higher mean blood pressure than most other groups. The antihypertensive effects of a 12-week aerobic exercise program were examined on 11 low-SES Black children, ages 8-12, who had blood pressure above the 95th percentile. A multiple baseline across three groups of children with baseline and exercise conditions was conducted. After the introduction of the exercise program, there were significant decreases in diastolic and systolic blood pressure. Cardiovascular fitness improved concurrently. The results suggest that vigorous exercise can decrease the blood pressure of low-SES hypertensive Black children.

Black or African American↗
PubMed1989

Evaluation of uncertainty in input parameters to pharmacokinetic models and the resulting uncertainty in output.

Physiologically-based pharmacokinetic (PBPK) models may be used to predict the concentrations of parent chemical or metabolites in tissues, resulting from specified chemical exposures. An important application of PBPK modeling is in assessment of carcinogenic risks to humans, based on animal data. The parameters of a PBPK model may include metabolic parameters, blood/air and tissue/blood partition coefficients, and physiological parameters, such as organ weights and blood flow rates. Uncertainty in estimates of these parameters results in uncertainty regarding tissue concentrations and resulting risks. Data are reviewed relevant to the quantification of these uncertainties, for a PBPK model-based risk assessment for tetrachloroethylene. Probability distributions are developed to express uncertainty in model parameters, and uncertainties are propagated by a sequence of operations that simulates processes recognized as contributing to estimates of human risk. Distributions of PBPK model output and human risk estimates are used to characterize uncertainty resulting from uncertainty in model parameters.

Animals↗
PubMed1989

Attitudes of French-Canadian university students toward use of condoms: a structural analysis.

164 French-Canadian university students took part in a study analyzing the factorial pattern of attitudes toward the use of condoms. A principal component analysis identified 7 factors, namely, positive general attitude toward use of condoms, contraceptive security, inhibition of sexual pleasure, inconvenience, embarrassment, responsibility, and lessening of physical pleasure.

Adult↗
PubMed1987

Phase II study of Zoladex depot in advanced prostatic cancer with special reference to criteria of response and survival.

Zoladex is a potent decapeptide analogue of luteinising hormone releasing hormone (LHRH). The drug is formulated as a 3.6 mg depot dispersed in a matrix of d,l-lactide-glycolide copolymer, which is totally biodegradable. This formula releases drug continuously for at least 28 days and reliably suppresses serum testosterone into the castrate range. The effect of the depot was studied in 29 patients with locally advanced or metastatic carcinoma of the prostate. Average age at entry was 71 years (range 52-87) and follow-up was from 13.5 to 34.5 months (median 23). Endocrine studies showed that medical castration was maintained in all cases. Three patients experienced bone pain in the first month of treatment and two others had temporary nephrostomies for worsening ureteric obstruction. Subjective improvement was seen in 23/28 cases (82%). There were no complete responses, but partial response was seen in 24/28 (85.7%) using our own criteria, 24/28 (85.7%) using the criteria recommended by the British Prostate Group (BPG) and 15/28 (53.6%) using NPCP criteria. Stable disease was seen in 3/28 patients (10.7%) by our own or BPG criteria, and in 12/28 patients (42.9%) according to NPCP criteria. Progression of disease was measurable in 21 patients (72.4%) whatever criteria were applied; 11/29 (37.9%) have died, giving a median survival of 10 months (range 2.4-26). Following these encouraging results, a multicentre randomised comparative study with stilboestrol 3 mg daily is being undertaken.

Aged↗
PubMed1986

Pharmacokinetic and endocrinological parameters of a slow-release depot preparation of the GnRH analogue ICI 118630 (zoladex) compared with a subcutaneous bolus and continuous subcutaneous infusion of the same drug in patients with prostatic cancer.

Seventeen patients with advanced prostatic cancer were treated with the gonadotrophin-releasing hormone analogue DSer (tBU)6 AzaGly 10 GnRH (ICI 118630), either as a constant SC infusion, or in the form of a monthly SC slowrelease depot formulation, in which case patients were randomised to receive one of three doses. Six of these patients also received a 250-microgram SC bolus of ICI 118630, for pharmacokinetic studies, before starting the infusion or the depot. Drug levels were measured using a double-antibody radioimmunoassay. In contrast to the SC infusion, which gave a smooth serum 118630 level profile, drug release from the depot preparation was not constant, levels varying in a predictable manner throughout each 28-day period, reaching a peak proportional to the dose of ICI 118630 received, between days 15 and 18 of each cycle. With all methods of administration there was an initial rise in LH, usually followed by a rise in testosterone, after which the SC infusion and the depot were both effective in reducing serum LH to basal levels and testosterone into the castrate range within 1 month. It is too early to make any assessment of clinical response; however, depot treatment was well tolerated: Four patients experienced an initial flare in bone pain, probably related to the initial rise in testosterone, and twelve patients experienced flushing; one patient with pre-existing hydronephrosis and hydroureter developed renal failure, possibly related to a tumour flare reaction. No patients have experienced cardiovascular side effects or local reaction.

Buserelin↗