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T Clarke

Publications and source records attributed to T Clarke.

At least 19 recordsLinked to original sources
PubMed2005

Assessing intervention effects in a community-based trial to reduce self-harm: a methodological case study.

This paper considers the assessment of the impact of a community-based randomized controlled trial to reduce repeat deliberate self-harm. It considers the drawbacks in simplistic applications of conventional significance testing procedures, as well as possible failures regarding the statistical assumptions underlying such tests. Instead, the paper considers how relevant prior information might be incorporated within a fully Bayesian-model-based assessment procedure. The model includes a latent trait approach to patient morbidity; controlling for morbidity and other patient characteristics enhances the impact of the intervention (measured by a hazard rate ratio). If allowance is made for external information (e.g. ethical approval of the treatment), the weight of evidence shifts towards a positive intervention effect.

Adolescent↗
PubMed2005

Cytochrome c nitrite reductase: from structural to physicochemical analysis.

The recent structural characterization of the NrfA from Escherichia coli provides a framework to rationalize the spectroscopic and functional properties of this enzyme. Analyses by EPR and magnetic CD spectroscopies have been complemented by protein-film voltammetry and these are discussed in relation to the essential structural features of the enzyme.

Circular Dichroism↗
PubMed2003

Effects of breathing air containing 3% carbon dioxide, 35% oxygen or a mixture of 3% carbon dioxide/35% oxygen on cerebral and peripheral oxygenation at 150 m and 3459 m.

The effects of gas mixtures comprising supplementary 3% carbon dioxide, 35% oxygen or a combination of 3% CO(2) plus 35% O(2) in ambient air have been compared on arterial blood gases, peripheral and cerebral oxygenation and middle cerebral artery velocity (MCAV) at 150 m and on acute exposure to 3459 m in 12 healthy subjects. Breathing 3% CO(2) or 35% O(2) increased arterial blood oxygen at both altitudes, and the CO(2)/O(2) combination resulted in the most marked rise. MCAV increased on ascent to 3459 m, increasing further with 3% CO(2) and decreasing with 35% O(2) at both altitudes. The CO(2)/O(2) combination resulted in an increase in MCAV at 150 m, but not at 3549 m. Cerebral regional oxygenation fell on ascent to 3459 m. Breathing 3% CO(2) or 35% O(2) increased cerebral oxygenation at both altitudes, and the CO(2)/O(2) combination resulted in the greatest rise at both altitudes. The combination also resulted in significant rises in cutaneous and muscle oxygenation at 3459 m. The key role of carbon dioxide in oxygenation at altitude is confirmed, and the importance of this gas for tissue oxygenation is demonstrated.

Adult↗
PubMed2002

Evidence for separate disease phenotypes in intestinal Crohn's disease.

BACKGROUND: This study investigated the hypothesis that separate phenotypes of Crohn's disease exist which display differing patterns of recurrence with a tendency to preservation of phenotype between serial operations. METHODS: Some 483 abdominal operations (278 patients) were identified from a prospectively compiled database. Patterns of recurrence (reoperation) were analysed by Kaplan-Meier plots and log rank tests according to disease phenotype (perforated, stenosed or ulcerated). Serial operations were analysed by agreement of phenotype and microscopic features of disease using kappa statistics and correlation coefficients. RESULTS: There was no significant difference in recurrence according to disease phenotype (median reoperation-free survival time 43.0, 50.2 and 47.9 months for perforated, stenosed and ulcerated types respectively; log rank chi(2) = 3.5, P = 0.18). There was poor agreement in phenotype between serial operations (kappa = 0.22 for first/second operation and kappa= 0.15 for second/third operation) and no significant correlation between pathological features was identified (r between -0.19 and 0.48). CONCLUSION: No evidence was found for the existence of separate disease phenotypes with differing natural histories or underlying pathological characteristics.

Crohn Disease↗
PubMed2002

Can pre-colposcopy sessions reduce anxiety at the time of colposcopy? A prospective randomised study.

The main objective of this prospective randomised study was to evaluate whether offering pre-colposcopy group sessions reduces anxiety at the time of colposcopy. We also examined whether this strategy improved knowledge about abnormal smears and colposcopy and improved satisfaction with the colposcopy service provided. One hundred and forty-seven women undergoing colposcopy for the first time were randomised into two groups. The control group (n = 75) received conventional management. The study group (n = 72), in addition to conventional management, were invited to attend a pre-colposcopy group session led by a trained colposcopy nurse. Questionnaires were used to determine state anxiety inventory scores and knowledge scores at the time of randomisation, immediately before colposcopy and 6 weeks after the clinic visit. Satisfaction questionnaires were completed 6 weeks after the clinic visit. We found that women attending colposcopy clinics are anxious. Those women who attended the pre-colposcopy session had improved knowledge scores (P = 0.039) at the time of colposcopy and satisfaction (P = 0.037). However, the intervention failed to significantly reduce anxiety at the time of colposcopy (P > 0.05).

Adult↗
PubMed2001

The stowaways.

Explore the source record for details and available documents.

Adenosine Triphosphate↗
PubMed2001

Polio's last stand.

Explore the source record for details and available documents.

Disease Outbreaks↗
PubMed2001

Activation of postsynaptic 5-HT(1A) receptors by fluoxetine despite the loss of firing-dependent serotonergic input: electrophysiological and neurochemical studies.

Systemic doses of fluoxetine slow dorsal raphe cell firing by blocking the reuptake carrier located in the cell body region with the surplus 5-HT thus generated activating inhibitory autoreceptors. The concurrent actions of fluoxetine on postsynaptic receptors in raphe projection areas has not been as thoroughly investigated, although it is presumed that a reduction in cell firing should curtail these targeted effects. The goal of the present studies was to assess the degree of postsynaptic receptor activation obtained with fluoxetine and relate it to cell body autoreceptor activation and the level of extracellular 5-HT obtained at the nerve endings. Changes in firing rates of CA3 hippocampal neurons following systemic administration of fluoxetine were used as a marker of SSRI-dependent changes in postsynaptic 5-HT receptor activation; monitoring of unit activity of neurons in the dorsal raphe nucleus served to gauge the degree of serotonergic input in a parallel series of animals. Estimates of the corresponding changes in terminal 5-HT release in the CA3 region were analyzed by microdialysis. The results indicate that fluoxetine inhibits hippocampal cell firing in a dose-dependent manner (ED(50) = 4.4 mg/kg i.v.) and one sensitive to pretreatment with the 5-HT(1A) antagonist WAY-100,635. Within the same dose range, increases in hippocampal extracellular 5-HT approaching 300% above basal levels were achieved. Both the changes in hippocampal neuronal activity and extracellular 5-HT are evident at doses of fluoxetine in excess of that required to inhibit dorsal raphe cell firing (ED(50) = 1.1 mg/kg i.v.). Taken together, these data suggest that increases in extracellular levels of 5-HT on the order of that observed are sufficient to alter postsynaptic excitability and that this accumulation of synaptic 5-HT and the subsequent activation of postsynaptic 5-HT(1A) receptors are achievable despite loss of firing-dependent 5-HT release.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

A consensus driven method to measure the required number of intensive care nurses in Australia.

This paper describes a methodology for determining the number of nurses required to staff Australia's intensive care unit (ICU) beds. The evidence used is level IV, that is the use of expert panel opinion, and it is the strongest and most accurate attempt yet to describe how Australia's ICU beds should be staffed with nurses. The researchers provide ratios of staffing applicable to a variety of situations that should be of use to ICU managers and hospital administrators. Equally, the broader calculations explaining the national supply and demand needs provide an easy to use approach and explanation suitable to health professionals, health administrators, policy advisors, governments, politicians and the broader community. Limitations of the approach and further recommendations are made to encourage future work in this area. Finally, a strong correlation between the number of available 'open' ICU beds in Australia and the number of nurses actually working in ICU at any given time is well demonstrated using the methodology outlined in this paper. Clarification of scope and terminology: This paper focuses on the nursing requirements of ICUs only; occasionally we use the word critical care nurse--this generally refers to those nurses who have completed a generic critical care nursing course but who, for the purposes of our study, are working in ICUs. Critical care units encompass ICUs but may also encompass recovery room, cardiothoracic units, coronary care, emergency departments and many other environments where critically ill patients are cared for and treated. This paper does not cover the broader scope of critical care units, only ICUs.

Australia↗
PubMed2001

Can we predict who will return to a genitourinary clinic?

One hundred and eighty-eight first-time attenders at a genitourinary (GU) clinic were monitored to establish who returned following discharge after treatment. Thirty-six (19%) returned within 2 years with a new infection. The re-attenders did not differ significantly from the rest of the cohort by age, gender or occupation, nor did they differ in their sexual history and psychological variables. Re-attenders were significantly more likely to have consulted their general practitioner (GP) in the 6 months prior to their first clinic attendance.

Female↗
PubMed2001

Carbon dioxide contributes to the beneficial effect of pressurization in a portable hyperbaric chamber at high altitude.

Regional cerebral oxygenation (rSO2) and peripheral oxygen saturation (SpO2) have been studied in subjects inside a portable hyperbaric chamber at altitude during pressurization. The effects of the accumulation of carbon dioxide within the chamber on rSO2 and SpO2 have also been investigated. Three studies of cerebral regional oxygenation were undertaken, using near-IR spectroscopy, in subjects who had ascended to 3475 m in the Alps, 4680 m in the Andes or 5005 m in the Himalayas. At 3475 m and 5005 m the effects of the removal of inspired carbon dioxide by a soda lime scavenger were also studied. On pressurization of the chamber to 19.95 kPa, inspired carbon dioxide rose within the chamber from 0.03% (0.06 kPa) ambient to over 1% (1.3 kPa). At 5005 m, SpO2 rose from a baseline of 79.5% (S.D. 4.5%) to 95.9% (2.0%) (P<0.0001), and cerebral rSO2 rose from 64.6% (3.4%) to 69.4% (3.6%) (P<0.0001). The introduction of a soda lime CO2 scavenger into the breathing circuit resulted in a drop in SpO2 from 95.9% (2.03%) to 93.6% (2.07%) (P<0.001) and a fall in rSO2 from 69.4% (3.64%) to 68.5% (3.5%) (P<0.01). Chamber pressure was maintained throughout at 19.95 kPa. Similar changes were seen at the other altitudes. Cerebral rSO2 increased rapidly following pressurization at all three altitudes. Scavenging of inspired carbon dioxide was associated with a significant fall in cerebral rSO2 and SpO2, and we estimate that the contribution of carbon dioxide may account for up to one-third of the beneficial effect of the portable hyperbaric chamber.

Adult↗
PubMed2001

The HELLP syndrome: maternal and perinatal outcome.

The HELLP syndrome is a rare condition with a variable presentation, and in general, the outlook for mother and baby is felt to be poor. The aims of this study were to determine the maternal and perinatal outcome in cases of the HELLP syndrome at the Rotunda hospital over a five-year period. A retrospective review of all cases of confirmed HELLP syndrome from 1/1/95 to 1/9/99 was undertaken. Antenatal, intrapartum and neonatal data and in particular, maternal and neonatal complications were recorded. There were 20 cases of HELLP syndrome over the 5-year period. Mean maternal age was 29.8 (19-43) years. 70% were nulliparous. 80% delivered within 24 hours of diagnosis. 85% were delivered by caesarean section. Mean gestation at delivery was 33.5 (24-41) weeks, 65% of which were preterm. 70% of the babies were admitted to the neonatal intensive care unit (NICU). Mean birth weight was 1923g (440-4640g). Mean length of stay was 23.8 (1-68) days. 40% developed respiratory distress syndrome (RDS) with a mean duration of ventilation for these infants of 2.4 (0.5-7) days. There were 2 perinatal deaths both of whom weighed <500g. 95% of women were admitted to the High Dependency Unit. There were no maternal deaths. The mean interval to resolution of laboratory indices to within normal reference ranges was 11 (2-30) days. Maternal morbidity was high, but short-term, with full resolution in all cases. Once the diagnosis was made, delivery was immediate. The neonatal morbidity was also high and was most closely related to the gestation at delivery.

Female↗
PubMed2001

Questionnaire on practices and priorities in neonatal care in Ireland.

As part of a process of audit of neonatal practice, a questionnaire on clinical practice and priorities which need to be addressed was sent to all consultant neonatologists, and to a consultant paediatrician in all other units caring for newborn infants, in the Republic of Ireland. The response rate was 88% (22 out of 25 replied). Thirteen respondents specified greater than 24 weeks and/or greater than 500 grams as the criteria at which infants were resuscitated. Eleven routinely intubated very premature infants. Seven treated any infant intubated for respiratory distress syndrome with surfactant, and seven sometimes used prophylactic surfactant. Poor perfusion or low blood pressure was the most common criterion for volume expansion during the first hour, using albumen (15 of 22), fresh frozen plasma (10), whole blood (9), normal saline (20 and haemacell (1). Most (18 of 22) used steroids for established bronchopulmonary dysplasia. Oral feeds were generally begun "as soon as possible". Persistent foetal circulation was treated with various vasodilators, tolazoline (14 of 22), magnesium sulphate (8) and nitric oxide (4). The main local priorities noted are the need for more neonatally trained nursing and / or medical staff. Almost all respondents noted the need for a national neonatal transport system. While this summary reveals a considerable variation in clinical practice this variation reflects the lack of evidence on which to base clinical decision making. Where evidence exists from clinical trials considerable uniformity exists in clinical decision making and practice. This study highlights the need for continued audit of clinical practice and the essential role clinical research plays in informing decision making in practice.

Birth Weight↗
PubMed2000

Development of a high-performance liquid chromatographic-mass spectrometric assay for the specific and sensitive quantification of Ro 64-0802, an anti-influenza drug, and its pro-drug, oseltamivir, in human and animal plasma and urine.

Oseltamivir phosphate (Ro 64-0796/002) is a pro-drug of the anti-influenza neuraminidase inhibitor, Ro 64-0802, and as Tamiflu, has been developed for the treatment of both A and B strains of the disease. This paper describes an HPLC-MS-MS assay for both compounds in plasma and urine which fulfils all of the criteria for a good analytical method. It is sensitive with limits of quantification of 1 and 10 ng/ml for the pro-drug and active neuraminidase inhibitor, respectively. It is both accurate and precise with typical coefficients of variation from some 5,000 quality control samples of approximately +/-3 and +/-6%, respectively. Extensive stability studies have demonstrated the absence of significant problems associated with the decomposition of either compound, although ex vivo hydrolysis of Ro 64-0796 to Ro 64-0802 in rodent plasma has to be prevented by the use of the esterase inhibitor, dichlorvos.

Acetamides↗