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Biomedical subjects

I Boyd

Publications and source records attributed to I Boyd.

18 recordsLinked to original sources
PubMed2000

Clinical features of tiaprofenic acid (surgam) associated cystitis and a study of risk factors for its development.

A case-control study was performed to describe the clinical course and identify risk factors predisposing to the development of tiaprofenic acid associated cystitis. Cases were identified from reports to the Australian Adverse Drug Reactions Advisory Committee and a two-year (1995-1996) national surveillance programme. Definition of a case was onset of symptoms of cystitis while taking tiaprofenic acid with pyuria (>10 WBC/microl) and/or hematuria (>10 RBC/microl), and no evidence of urinary tract infection. Definitions of "prescriber-matched" and "unmatched" controls were those who had been prescribed tiaprofenic acid by the same prescriber within 12 months of the case without developing cystitis or were identified from the databases of local pharmacies of the cases respectively. 81 of 109 identified cases and 109 of 184 potential controls completed a standardised interviewer-administered questionnaire. Median time between the commencement of tiaprofenic acid and symptom onset was 6. 3 months (range 0.1-47.1 months). Median interval between presentation to doctor and drug cessation was 3.0 months (range 0-24. 5 months). In half the patients, symptoms resolved within 14 days of ceasing therapy. Increasing age was a risk factor for the development of tiaprofenic-acid associated cystitis, age >70 years-odds ratio 3.2 (95% confidence interval 1.3-7.9) compared with age <55 years. Patients taking aspirin had a reduced risk (odds ratio 0.3, 95% confidence interval 0.1-0.9). Dose and amount of fluid consumed per day were not related to the risk of cystitis. Earlier recognition of tiaprofenic acid associated cystitis can potentially reduce the morbidity related to this condition. Apart from an increased risk among older patients, it is likely that this condition represents a drug reaction that cannot be predicted from clinical variables.

Adult↗
PubMed1997

Heart rates and abdominal temperatures of free-ranging South Georgian shags, Phalacrocorax georgianus

The South Georgian shag (Phalacrocorax georgianus) shows a remarkable diving ability comparable to that of penguins, yet nothing is known of the physiology of these birds. In this study, heart rates and abdominal temperatures were recorded continuously in four free-ranging South Georgian shags using an implanted data-logger. A time&shy;depth recorder was also attached to the back of the implanted birds to record their diving behaviour. The diving behaviour of the birds was essentially similar to that reported in other studies, with maximum dive durations for individual birds ranging between 140 and 287 s, and maximum depths between 35 and 101 m. The birds, while at the nest, had a heart rate of 104.0&plusmn;13.1 beats min-1 (mean &plusmn; s.e.m.) and an abdominal temperature of 39.1&plusmn;0.2 &deg;C. During flights of 221&plusmn;29 s, heart rate and abdominal temperature rose to 309.5&plusmn;18.0 beats min-1 and 40.1&plusmn;0.3 &deg;C, respectively. The mean heart rate during diving, at 103.7&plusmn;13.7 beats min-1, was not significantly different from the resting values, but the minimum heart rate during a dive was significantly lower at 64.8&plusmn;5.8 beats min-1. The minimum heart rate during a dive was negatively correlated with both dive duration and dive depth. Abdominal temperature fell progressively during a diving bout, with a mean temperature at the end of a bout of 35.1&plusmn;1.7 &deg;C. The minimum heart rate during diving is at a sub-resting level, which suggests that the South Georgian shag responds to submersion with the 'classic' dive response of bradycardia and the associated peripheral vasoconstriction and utilisation of anaerobic metabolism. However, the reduction in abdominal temperature may reflect a reduction in the overall metabolic rate of the animal such that the bird can remain aerobic while submerged.

Journal Article↗
PubMed1994

THE USE OF HEART RATE TO ESTIMATE OXYGEN CONSUMPTION OF FREE-RANGING BLACK-BROWED ALBATROSSES DIOMEDEA MELANOPHRYS

Heart rates (fh) and rates of oxygen consumption (V(dot)O2) were measured in eight black-browed albatrosses (Diomedea melanophrys) when walking on a treadmill, with the aim of using fh to predict V(dot)O2 in free-ranging albatrosses. The resulting relationship between the variables was: V(dot)O2 (ml min-1) = [0.0157fh (beats min-1)]1.60, r2=0.80, P<0.001. In addition to the calibration procedure, six of the albatrosses were injected with doubly labelled water (DLW), and fh and V(dot)O2 were monitored continuously over a 3 day period while the birds were held in a respirometer. During the 3 day period, the birds were walked for up to 3&shy;4 h day-1 in bouts lasting approximately 0.5 h. The heart rate data were used to estimate the metabolic rates of these birds using the above regression. Estimates of metabolic rate derived from fh, DLW and respirometry did not differ (ANOVA; P=0.94), primarily because of the variance between individual birds. There was also no significant difference between the different estimates obtained from the different equations used to calculate energy expenditure from the DLW technique (ANOVA; P=0.95). Mean estimates of V(dot)O2 from fh under active and inactive conditions differed from measured values of V(dot)O2 by -5.9 % and -1.7 % respectively. In addition, the estimates of V(dot)O2 from fh at different walking speeds did not differ significantly from the measured values. It appears that, in the black-browed albatross, fh is as good a predictor of the mean metabolic rate of free-ranging birds as DLW or time&shy;energy budgets combined with either respirometry or DLW. However, the method should be applied to as many individuals and as many instances of a particular behaviour as possible. The heart rate technique offers potential for much more detailed analyses of the daily energy budgets of these birds, and over much longer periods, than has previously been possible.

Journal Article↗
PubMed1993

Risk factors for development of flucloxacillin associated jaundice.

OBJECTIVES: To identify risk factors predisposing to the development of flucloxacillin associated jaundice. DESIGN: Case-control study. Medical records of cases and controls were reviewed and information recorded on standard data collection forms. SETTING: Alfred Hospital recruiting subjects from Melbourne, Sydney, and Brisbane. SUBJECTS: Cases were defined as patients who had developed jaundice within eight weeks of stopping flucloxacillin, biochemical test results suggesting cholestasis, normal calibre bile ducts, and not been taking recognised hepatotoxic drugs. 51 of the 53 patients referred were included in the study. Four controls for each case were randomly selected from the patient register of the prescribing doctor. These were defined as patients who had been prescribed flucloxacillin without developing jaundice. MAIN OUTCOME MEASURES: Demographic characteristics, medical history, indication for flucloxacillin, dose, route and duration of treatment, other drugs, smoking, and previous drug allergies or use of flucloxacillin. RESULTS: Increasing age and a prolonged duration of flucloxacillin treatment were found to be risk factors for the development of jaundice. Patients aged over 55 years had an odds ratio of 18.61 (95% confidence interval 5.16-67.17) compared with patients under 30. The odds ratio for patients prescribed flucloxacillin for over 14 days was 7.13 (2.90 to 17.58) compared with patients treated for 14 days or less. Dose and route of administration were not related to the risk of jaundice. CONCLUSIONS: Older patients and those receiving flucloxacillin for longer than two weeks are at a substantially greater risk of jaundice. Careful consideration of the risk-benefit ratio is required when flucloxacillin is used in these settings.

Adult↗
PubMed1983

Comparison of the effects of atracurium and tubocurarine on heart rate and arterial pressure in anaesthetized man.

The effects of atracurium and tubocurarine on heart rate and arterial pressure were studied in anaesthetized patients. A bolus of 0.6 mg kg-1 of either atracurium or tubocurarine was administered. Following atracurium, the change in heart rate was minimal (mean +/- SEM: -1.6 +/- 1.3 beat min-1) whereas after tubocurarine heart rate was increased (mean +/- SEM: +9.9 +/- 1.9 beat min-1). Atracurium produced a transient decrease in arterial pressure in 28% of subjects; by the 4th min after its injection the change was minimal (mean +/- SEM: -1.5 +/- 1.1 mm Hg). Tubocurarine produced an initial decrease in mean arterial pressure in all patients, of up to 50% of control values. In the 4th min following its injection arterial pressure was still significantly different from control (mean +/- SEM: -10 +/- 1.5 mm Hg). Endotracheal intubation caused an increase in arterial pressure in all subjects. It is concluded that atracurium has minimal effects on heart rate and arterial pressure when compared with tubocurarine. It does not appear to have a vagal blocking action.

Adult↗
PubMed1979

Relationship between the antibacterial activity towards Escherichia coli NCTC 5933 and the physico-chemical properties of some esters of 3,4,5-trihydroxybenzoic acid (Gallic acid).

Aqueous solubilities, oleyl alcohol: water and octanol: water partition coefficients, RM values, reduction in surface tension of water, relative antioxidant activities and pKa values, were determined for gallic acid and a series of its alkyl esters. Correlations were sought between these physico-chemical measurements and MIC, MBC and killing-rate determinations against Escherichia coli. Variations in antibacterial activity generally correlated well with partition parameters, but these correlations did not accurately predict the cut-off point in antibacterial activity.

Chemical Phenomena↗
PubMed1978

Correlations between physico-chemical properties and antimicrobial activity for some glycolmonophenyl ethers.

Aqueous solubilities, octanol: water partition coefficients and Rm were determined for twelve glycolmonophenyl ether analogues. Their correlation with growth inhibitory activity towards eight bacterial, yeast and fungal species was assessed. Correlations were also sought between bactericidal activity and inhibition of respiration of E. coli suspensions with these physico-chemical properties. Variations in antimicrobial activity generally correlated well with aqueous solubility. Partition coefficients were found to correlate poorly with biological response with the exception of those correlations involving Gram-negative micro-organisms. Regression equations relating solubility to biological activity generally varied significantly between micro-organisms and for different biological responses with E. coli. This suggested the possibility of different problems of drug penetration in different microbial species and/or different sites of action for the various biological responses.

Anti-Bacterial Agents↗
PubMedDate not supplied

The origin(s) of the periarticular osteophytes of osteoarthritic knee joints.

Oestophites obtained from the margins of 25 osteoarthritic knee joints undergoing replacement have been investigated using a battery of tinctorial stains. The microarchitecture of the osteophyte appears to be identical to that of the normal articular cartilage. Other findings suggest that oesteophytes are derived from hyperplasia of the surface chondrocytes at the 'marginal transitional zone'.

Cartilage, Articular↗