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Biomedical subjects

C Brett

Publications and source records attributed to C Brett.

17 recordsLinked to original sources
PubMed2005

Cranial computed tomography in trauma: the accuracy of interpretation by staff in the emergency department.

OBJECTIVES: Cranial computed tomography (CT) is replacing skull radiography in head trauma. Rapid radiological opinions on these images may not always be available. We assessed the ability of our permanent emergency department staff to interpret the images. METHODS: A retrospective series of 100 consecutive cases was reviewed and interpreted by five permanent emergency department medical staff, and their interpretation compared with the consensus opinion of two radiologists. RESULTS: An overall agreement of 86.6% (95% confidence interval (CI) 83.4 to 89.9) was achieved, with a false negative rate of 4.2% (95% CI 3.9 to 4.3). No findings that would have changed the overnight management of any patient were missed. CONCLUSIONS: Our results for CT scans are similar to studies of interpretation of other radiographic images in emergency departments. Our emergency staff could safely make the initial interpretation of cranial CT images in trauma out of hours, and formal reporting may wait until a suitably experienced radiologist is available.

Adult↗
PubMed2002

P-R segment depression: an early diagnostic feature in acute pericarditis: a telephone survey of UK accident and emergency departments.

P-R segment depression is an early ECG change in the evolution of acute pericarditis. This is widely recognized in the USA and appears in several major emergency medicine texts. A telephone survey was conducted to gain an overview of the knowledge of accident and emergency career doctors in the UK. We hope to use the results to highlight this potentially useful sign. One hundred accident and emergency departments, listed in the 1999 British Association for Accident and Emergency Medicine as seeing more than 40,000 new patients per year, were contacted in a telephone survey. The registrar, staff grade or consultant on call was asked to respond to a brief questionnaire. One hundred accident and emergency (A&E) specialist doctors were contacted--60 specialist registrars, 23 consultants and 17 staff grades. Of those questioned, 24% had a background in general medicine. The remainder had trained in surgery, A&E medicine or anaesthetics. None of the doctors questioned volunteered knowledge of P-R depression when asked an open question. Six doctors (6%) admitted, when prompted, to having previously heard of this sign. Knowledge of P-R segment depression is not widespread amongst UK A&E specialists. It is a potentially useful early electrocardiogram change in the evolution of acute pericarditis. Its recognition may aid diagnosis and prevent the inappropriate administration of thrombolytic therapy.

Adult↗
PubMed2001

Let's swap: early understanding of social exchange by British and Nepali children.

Recent research with adults has suggested that they readily understand conditional rules that include a deontic or prescriptive element. The possibility that young children might also understand such conditional rules when they are embedded in the context of an exchange agreement was explored in three studies. Children 3-7 years of age listened to stories in which two protagonists agreed to an exchange of mutual benefit. Children tested both in Britain and Nepal were accurate in identifying (1) when either protagonist had reneged on the agreement and (2) when both protagonists had kept the agreement. The findings indicate that young children are sensitive to the obligations that stem from an exchange agreement even if it is made between equals rather than imposed by adult authority.

Child↗
PubMed1998

Interferon-gamma and monoclonal antibody 131I-labeled CC49: outcomes in patients with androgen-independent prostate cancer.

To assess the tumor targeting, safety, and efficacy of monoclonal antibody 131I-labeled CC49 in patients with androgen-independent prostate cancer, 16 patients received 75 mCi/m2 of the radiolabeled antibody after 7 days of IFN-gamma pretreatment. Sequential tumor biopsies in three patients showed a median 5-fold (range, 2-6-fold) increase in the proportion of cells staining positively for the TAG-72 antigen, whereas one showed a decrease in staining. Fourteen patients received 131I-labeled CC49, whereas 2 showed a disease-related decrease in performance status, precluding antibody treatment. The antibody localized to sites of metastatic androgen-independent prostate cancer in 86% (12 of 14; 95% confidence interval, 57-95%) of cases. Both osseous and extraosseous sites were visualized, and in six (42%) patients, more areas were visible when the radioimmunoconjugate was used than were apparent when conventional scanning techniques were used. The localization of the conjugate in the marrow cavity was usually a site not visualized by the radionuclide bone scan, in which the isotope localizes primarily to the tumor-bone interface. The dose-limiting toxicity was thrombocytopenia because five (36%) patients showed grade IV and seven (50%) showed grade III effects. In addition, six (42%) patients, four of whom were hospitalized, showed a flare in baseline pain, and four showed a decrease in pain. No patient showed a >50% decline in prostate-specific antigen, although radionuclide bone scans remained stable in four cases for a median of 4 months. The results are consistent with dosimetry estimates showing that the delivered dose to tumor was subtherapeutic and suggest that approaches that exclusively target the bone tumor interface or the marrow stroma may be unable to completely eradicate disease in the marrow cavity. For CC49, improving outcomes would require repetitive dosing, which was precluded by the rapid development of a human antimouse antibody response.

Aged↗
PubMed1997

Life and death on the waiting list for coronary bypass surgery.

AIM: To assess the baseline characteristics of patients referred for isolated coronary bypass surgery (CABG), waiting times for coronary bypass surgery and clinical events while waiting for coronary bypass surgery. To compare the New Zealand priority scoring system with a previously validated Ontario urgency score. METHODS: Outcomes in a consecutive case series of 88 patients referred from Christchurch Hospital for coronary bypass surgery between July 1 and December 31 1993 were compared with a previous Christchurch case series and a contemporary Canadian case series. Patients were stratified according to both Ontario and New Zealand priority scores. RESULTS: Of 88 patients, one patient died prior to surgery, 79 had undergone coronary bypass surgery (with three deaths), and eight were still waiting as at December 31 1995. Twenty five percent of patients had left main disease, another 60% had multivessel disease that included the proximal left anterior descending coronary artery and 64% had angina at rest or on minimal exertion. The median waiting time was 92 days (inter-quartile range 20-234), 8 (6-12) days in the 23 patients who underwent surgery as in-hospital cases, and 181 (83-295) in those who waited at home. Patients with left main disease waited a median of 41 (11-205) days. While waiting at home one patient died, one patient suffered a myocardial infarction, and 17 patients were readmitted with unstable angina. Readmissions were not predicted by New Zealand or Ontario priority scores, nor by clinical variables. CONCLUSIONS: Thresholds for referral are very similar, but waiting times for coronary bypass surgery are far longer in New Zealand than Canada. The long waiting times are a considerable cost to both patients and government. Priority scores facilitate comparison between countries but they may not predict readmission to hospital while on a long waiting list.

Aged↗
PubMed1997

Bicalutamide for advanced prostate cancer: the natural versus treated history of disease.

PURPOSE: To determine the therapeutic effects of bicalutamide 200 mg in patients with prostate cancers of different hormone sensitivities. METHODS: Patients with progressive prostate cancer were treated with bicalutamide 200 mg daily. Before treatment, patients' tumors were classified on the basis of prior hormone exposure and by serum testosterone levels into androgen-dependent and androgen-independent groups. Prior exposure to flutamide and response to flutamide withdrawal was also considered. Outcomes were reported independently on the basis of posttherapy changes in prostate-specific antigen (PSA), measurable disease, and radionuclide bone scans. RESULTS: Outcomes varied by prior hormone exposure as a higher proportion of patients with progression of androgen-dependent tumors showed posttherapy PSA decreases of more than 50% or more than 80%, measurable disease regression, and improvement on radionuclide bone scans than did patients with androgen-independent progression. Within the category of androgen-independent progression, clinical benefit was observed in patients who had previously progressed on flutamide, independent of the response to flutamide withdrawal. Patients who had progressed on a gonadotropin-releasing hormone (GnRH) analog alone had a low response proportion, whereas those who progressed after two or more hormone therapies did not respond. Overall, the drug was well tolerated. After progression on bicalutamide monotherapy, one third of patients with androgen-dependent progression responded to medical castration with a GnRH analog. CONCLUSION: Classifying patient tumors on the basis of prior hormone exposure permits a more precise estimate of the potential benefit of a specific hormone therapy for the individual patient. The precision is further increased by reporting the effects of a drug on each parameter of disease independently. The difference in outcomes for patients with androgen-independent progression suggests that the specific hormone therapy administered and the response to that therapy can influence the biology of the relapsing tumor and the sensitivity to subsequent therapies. The sensitivity to bicalutamide after progression on flutamide deserves further study.

Aged↗
PubMed1988

Short-term hemodynamic effects of captopril in infants with congestive heart failure.

We studied the short-term hemodynamic effects of captopril in ten infants with congestive heart failure secondary to large left-to-right shunts who were refractory to routine medical management with digoxin and diuretics. During cardiac catheterization, captopril (0.5 to 1.0 mg/kg) was administered by nasogastric tube. For the entire group, mean systemic blood flow, pulmonary blood flow, and the pulmonary-to-systemic blood flow ratio did not change significantly after captopril administration. However, in the seven patients in whom baseline systemic vascular resistance was greater than 20 U/m2, captopril decreased the pulmonary-to-systemic blood flow ratio. In contrast, in the three patients in whom baseline systemic vascular resistance was less than 20 U/m2, captopril increased the pulmonary-to-systemic blood flow ratio. We conclude that captopril acutely decreases the pulmonary-to-systemic blood flow ratio in infants with large left-to-right shunts who have elevated systemic vascular resistance. Renal function must be monitored closely when using captopril.

Captopril↗
PubMed1985

Developmental changes in myocardial contractile reserve in the lamb.

We have assessed serial changes in myocardial contractility and reserve in the normal lamb over the first month of life using an in vivo adaptation of the endsystolic pressure-volume relationship. Via a left thoracotomy, we insert a catheter tip pressure transducer into the left ventricle, affix an echo transducer onto the left ventricular epicardium, place an electromagnetic flow transducer around the pulmonary artery, and insert catheters for monitoring and infusions. We measure contractility by generating left ventricular wall stress-volume index (the cube of dimension) curves, at the same time increasing afterload by infusing phenylephrine. The slope of the endsystolic wall stress-volume index relationship is our index of contractility. Weekly studies were performed at rest and during isoproterenol infusion in 12 animals, and after propranolol administration in four. The data showed a progressive decrease in resting contractility but no change in maximal contractility during isoproterenol infusion over the 4 wk. Taking each week separately, the average increase in contractility during isoproterenol infusion was small at 1 wk (13%), moderate at 2 and 3 wk (24 and 26%, respectively), and large at 4 wk (79%). beta-Adrenergic blockade with propranolol caused a significant decrease in contractility in three of four animals studied at 1 wk, in only one of four animals at 2 wk, and in none of four animals at 3 or 4 wk. Thus, the newborn lamb shows a limited reserve in contractility that increases progressively with age; the limited reserve appears secondary to a high resting beta-adrenergic state.

Animals↗
PubMed1982

Prophylactic indomethacin therapy for patent ductus arteriosus in very-low-birth-weight infants.

We performed a double-blind, controlled study of prophylactic indomethacin therapy in 47 premature infants (less than 1700 g) who had subclinical patent ductus arteriosus. They received either indomethacin or placebo at a mean age of 2.9 days. Among the 25 infants weighing more than 1000 g, a hemodynamically important ductus shunt developed in only four of the 14 given placebo. The incidence of important shunts, the number of surgical ligations, and the duration of oxygen therapy were not appreciably different between the study groups. In contrast, among the 22 infants who weighed 1000 g or less, a major ductus shunt developed in 10 of the 12 given placebo. In the smaller infants indomethacin therapy was associated with a significantly lower incidence of major shunts, fewer surgical ligations, a decreased duration of oxygen therapy, and fewer days necessary to regain birth weight. We conclude that prophylactic indomethacin therapy in infants weighing under 1000 g prevents the later development of large ductus shunts and decreases morbidity.

Clinical Trials as Topic↗
PubMed1981

Developmental follow-up of hyperventilated neonates: preliminary observations.

A group of 13 newborn infants greater than 37 weeks' gestation were selected to be hyperventilated because of severe hypoxemia refractory to conventional mechanical ventilation, ie, failure to maintain PaO2 greater than 50 torr with an FIO2 of 1.0, despite PaCO2 less than or equal to 40 torr and pH greater than or equal to 7.40. Eleven survived; nine were available for follow-up evaluations. As a group, the nine infants were exposed to a PaCO2 less than or equal to 20 torr for 51.8 +/- 11.8 (mean +/- SEM) hours, to PaCO2 less than or equal to 15 torr for 11.8 +/- 3.3 hours, to a pH greater than 7.50 for 64.4 +/- 18.6 hours, and to a pH greater than or equal to 7.60 for 6.1 +/- 2.9 hours. One infant was lost to follow-up after a normal assessment at nine months. the other eight infants (seven AGA, one markedly SGA) were at least 1 1/4 years old at the time of evaluation. The seven AGA infants had a normal developmental quotient (mean 110 [range 96-130] by Stanford-Binet or Bayley assessment); the one SGA infant had a Bayley score of 89. All eight had normal neurologic examinations. These preliminary findings are reassuring with respect to neurologic and developmental outcome following prolonged hyperventilation.

Child Development↗
PubMed1980

Circulating prostaglandin E2 concentrations and incidence of patent ductus arteriosus in preterm infants with respiratory distress syndrome.

In several species prostaglandin E2 (PGE2) appears to be the most important prostanoid to regulate patency of the ductus arteriosus. We measured the arterial plasma concentration of PGE2 in 29 premature infants (17 with respiratory distress syndrome alone and 12 with respiratory distress syndrome and patent ductus arteriosus) to determine if there was an association between circulating PGE2 and patent ductus arteriosus. The PGE2 concentrations during the first two days after birth were higher than PGE2 concentrations after the third postnatal day (17.1 +/- 3.1 pg/ml, mean +/- SEM, n = 23, vs 6.12 +/- 0.63 pg/ml, n = 19, P < .005). By the third postnatal day, arterial concentrations were similar to adult venous values. There was no significant difference between the plasma PGE2 concentrations in the 12 infants with patent ductus arteriosus and the concentrations in the 17 infants who had no signs of patent ductus arteriosus. These findings do not support the hypothesis that an increased concentration of circulating PGE2 is the primary cause for the persistent patency of the ductus arteriosus in preterm infants with respiratory distress syndrome.

Ductus Arteriosus, Patent↗
PubMedDate not supplied

From the cholinergic gene locus to the cholinergic neuron.

The cholinergic gene locus (CGL) was first identified in 1994 as the site (human chromosome 10q11.2) at which choline acetyltransferase and a functional vesicular acetylcholine transporter are co-localized. Here, we present recent neuroanatomical, developmental, and evolutionary insights into the chemical coding of cholinergic neurotransmission that have been gleaned from the study of the CGL, and its protein products VAChT and ChAT, which comprise a synthesis-sequestration pathway that functionally defines the cholinergic phenotype.

Animals↗