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Biomedical subjects

M Peake

Publications and source records attributed to M Peake.

9 recordsLinked to original sources

Randomized trial of continuous positive airways pressure to prevent reventilation in preterm infants.

A prospective randomized controlled trial was performed comparing the use of a short period (24 hr) of postextubation nasal continuous positive airways pressure (CPAP) with direct extubation into headbox oxygen on the outcome of the need for reintubation within 7 days of initial extubation. Infants at less than 32 weeks of gestation who had received mechanical ventilation in the first 28 postnatal days and were being extubated for the first time were recruited. Ninety-seven babies were entered into the study (48 CPAP and 49 headbox oxygen). Twenty-four (49%) babies in the headbox group were reventilated within a week, compared to 16 (33%) in the CPAP group (P=0.17). By 14 days after initial extubation, 25 babies (51%) in the headbox group and 23 (48%) in the CPAP group required reventilation (P=0.9). There was a trend toward babies in the CPAP group requiring fewer reintubations (median, 2; range, 1-6) compared to those in the headbox group (median, 3; range, 1-7) (P=0.063). There was no significant difference between groups with respect to total number of days of ventilation (headbox median, 4; range, 1-24; CPAP median, 2; range, 1-20). In conclusion, this study showed that a short period of nasal CPAP is not associated with a reduction in reventilation.

Continuous Positive Airway Pressure↗

Bilirubin measured on a blood gas analyser: a suitable alternative for near-patient assessment of neonatal jaundice?

The reliability of a recently released total bilirubin assay for a blood gas analyser was assessed in two Australian hospital laboratories. The instrument computes total bilirubin concentration from multi-wavelength absorbance measurements of undiluted whole blood or plasma. Performance of the Radiometer ABL 735 blood gas analyser bilirubin method (software version 3.6) was compared with a proven Roche diazo method for Hitachi analysers, calibrated using primary standards prepared from NIST SRM 916a bilirubin. Acceptable bilirubin results were found over a wide concentration range for most neonatal samples of whole blood or plasma. For adult specimens, bilirubin results were approximately 10% lower on the blood gas analyser. Within-run imprecision (whole blood) was < 2.5%, between-day imprecision (synthetic controls) < 1.0%, and the bilirubin assay for both whole blood and plasma was linear to 1,000 micromol/L. Using sampling options from 35 microL to 195 microL, bilirubin results differed by less than 3%, with a 95 microL syringe option producing the highest results. We conclude that the Radiometer ABL 735 bilirubin assay is suitable for near-patient assessment of neonatal jaundice using whole blood, thus eliminating the need for sample centrifugation. Verification using laboratory methods can be used when required. A positive correction of approximately 10% is required for adult specimens to conform with Hitachi results (SRM 916a calibration), possibly due to the optical characteristics of the higher proportion of conjugated bilirubin and other substances present in most adult samples.

Adult↗

Performance of a novel spectrophotometric lithium assay on a routine biochemistry analyser.

A new spectrophotometric lithium assay was assessed after adaption to a Hitachi 917. Results on this analyser were in close agreement with lithium measured on a flame photometer (95% confidence interval+/-0.06 mmol/L, n = 120). Assay precision was <2.5% over a range of lithium concentrations from 0.5-3.0 mmol/L. The assay was linear to 3 mmol/L and interference from haemolysis, icterus, lipaemia and other metal ions was minimal. The assay is a useful substitute or "back-up" for traditional lithium assays. Improved "on-board" calibration stability (currently 24 h) is required by improving the stability of uncapped reagent.

Antimanic Agents↗

An ecdysteroid-responsive gene in a lobster - a potential crustacean member of the steroid hormone receptor superfamily.

The role of ecdysteroids in modulating exoskeletal growth during the moult cycle of Crustacea has been well described. However, little is known about the action of ecdysteroids at the level of gene transcription and regulation in Crustacea. This paper reports the cloning of an ecdysteroid responsive gene, HHR3, a potential Manduca sexta MHR3 homologue in the American lobster, Homarus americanus. Levels of HHR3 expression are up-regulated in response to in vivo injections of premoult concentrations (10(-6) M) of 20-hydroxyecdysone in the epidermal and muscle tissue of the lobster after 6 h. Maximal mRNA levels are observed after 21 h before returning to basal levels. In muscle tissue, elevated levels of HHR3 mRNA follow a time course similar to elevated actin mRNA expression in response to hormonal injection. In contrast, in eyestalk tissue, the HHR3 levels decline up to 21 h post-injection before rising to basal levels after 48 h. Eyestalk, epidermal and leg muscle tissue was extracted over the moult cycle to determine the levels of expression. In muscle, HHR3 is high during the premoult period that corresponds to the period of the moult cycle when the ecdysteroid titre is high. In the epidermis, HHR3 levels are also high during the premoult with elevated levels maintained into the postmoult period. In the eyestalk, mRNA levels of HHR3 show an opposite pattern of expression with low levels during premoult and postmoult and high levels found during the intermoult period. Our results provide novel evidence for an ecdysteroid responsive gene in a crustacean that has many similarities to MHR3 in Manduca and DHR3 in Drosophila melanogaster. This raises the question of whether a similar cascade of ecdysteroid responsive genes exist in other members of Arthropoda such as the Crustacea, as has been demonstrated in Drosophila. In addition, we provide further evidence for negative feedback regulation of ecdysteroids at the site of moult-inhibiting hormone (MIH) production in the lobster eyestalk.

Amino Acid Sequence↗

Clinical and histologic features of vulvar carcinomas analyzed for human papillomavirus status: evidence that squamous cell carcinoma of the vulva has more than one etiology.

The association between the human papillomavirus (HPV) and malignant neoplasms of the uterine cervix is well established; however, its role in the pathogenesis of vulvar cancer has not been well defined. This study correlates the clinical and histopathologic features of 21 invasive carcinomas of the vulva with the presence of HPV DNA as detected by Southern blot and polymerase chain reaction (PCR) analysis. By one or both techniques, HPV DNA was detected in 10 of the 21 tumors analyzed; all HPVs containing tumors hybridized with HPV-16 probes, although PCR also detected HPV-6 in two of the HPV-16-containing tumors. No HPV-18 DNA was detected in any tumor by PCR or Southern blot hybridization. Both the invasive cancer and the surrounding intraepithelial disease tended to display histopathologic features that usually could distinguish HPV-associated cancers from those without HPV DNA. The intraepithelial lesions associated with HPV-containing tumors were of the bowenoid type with koilocytosis, while tumors lacking HPV generally demonstrated a simplex type of intraepithelial lesion. Invasive tumors with no viral DNA were more frequently keratinizing than the HPV-containing cancers. Race, parity, hormonal therapy, and alcohol use did not affect the HPV status; however, HPV DNA was more prevalent in the tumors of younger women and in those with a history of tobacco use. Human papillomavirus status had no impact on the stage of disease or its prognosis. These findings identify two subsets of vulvar carcinoma cases based on HPV hybridization data and the histopathologic characteristics of the tumor.

Adult↗

Multi-centre clinical respiratory research: a new approach?

BACKGROUND: Recruitment to clinical trials organised by the research committee of the British Thoracic Society (BTS) has declined. We suspected that this was due to increasing workloads for consultant physicians in the National Health Service (NHS). We investigated possible causes in study 1 and a possible solution in study 2. METHODS: Study 1--a questionnaire was sent to BTS members listing possible factors that might deter them from entering patients into trials. These were scored on a 0-5 scale. Study 2--we set up 13 panels of experts to cover all major fields of respiratory medicine. They were asked to design projects that would address the most important research questions that could be answered by multi-centre clinical trials. We sent 11 projects for scoring to consultant members of the BTS who were asked to score them on scientific merit and on their ability to contribute patients to the study. RESULTS: Study 1--of the 59% of consultants who responded, 77% said that competition with increasing demands on their time was the major reason for not participating. Study 2--40% of consultants returned project scores. Three projects were subsequently selected for grant application. CONCLUSIONS: Clinical research in the UK is under threat from increasing workloads on consultants. One solution to this problem is a national approach to commission major projects. The most important clinical research questions might then still be answered in the limited time available to consultants.

Attitude of Health Personnel↗