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Biomedical subjects

M Barton

Publications and source records attributed to M Barton.

At least 19 recordsLinked to original sources
PubMed2006

Predictors of poor outcome in neonates with bacterial sepsis admitted to the University Hospital of the West Indies.

To determine factors that affect outcome in neonates with culture-proven sepsis, the charts of all neonates with culture-proven sepsis admitted to the University Hospital of the West Indies between January 1995 and December 2000 were reviewed retrospectively. Neonates who survived without developing any complications (favourable outcome group) were compared with those who died and/or developed severe complications during the course of treatment (poor outcome group). Chi-square tests were done to determine factors associated with poor outcome; univariate and multivariate logistic regression analyses were also performed. One hundred and thirty-five neonates had culture-proven sepsis, of which 89 (66%) were term infants and 46 (34%) were preterm. Male to female ratio was 1.6:1. One hundred and twenty-six (93%) survived and 9 (7%) died. Case fatality rates were higher for premature infants (15%) than for term infants (2%). Twenty-four (18%) of the neonates with culture proven sepsis had a poor outcome. Gram negative organisms accounted for 19 (70%) of the cases with poor outcome. Prematurity (p < 0.001), very low birthweight (p < 0.001) and female gender (p < 0.05) were factors associated with poor outcome. Strategies aimed at decreasing morbidity and mortality in neonates with sepsis must include measures that will decrease the incidence of prematurity and low birthweight.

Analysis of Variance↗
PubMed2005

Importance of radiation time and dose factors on outcome for childhood medulloblastoma.

The purpose of this study was to investigate the relationship of posterior fossa radiation therapy duration (PFRTD) and relapse-free survival (RFS) following adjuvant craniospinal RT for childhood medulloblastoma. A retrospective audit was performed assessing all children aged <18 years managed with adjuvant craniospinal RT for medulloblastoma in Australia and New Zealand in 1980-1993. Children receiving prolonged (>180 days) pre-RT chemotherapy were excluded. Data were obtained for potential prognostic factors in domains of patient, tumour and treatment factors. Radiation therapy time factors assessed were PFRTD and time interval from surgery to commencement of RT (SRTD). The end-point assessed was RFS and analysis was performed using Cox regression and Kaplan-Meier survival. One hundred and eighty-nine children were identified from 10 oncology units, with data available from 182 children for analysis. Median follow up was 5.3 years. Seventy-three per cent of children presented with disease confined to the cerebellum; 13% had initial neuraxis disease. Macroscopic resection was described in 54%; 42% received adjuvant chemotherapy. Median RT dose and RT duration to PF was 55 Gy and 45 days, respectively. Seventy-eight relapses occurred with a 10-year actuarial RFS of 58.2% (standard error +/- 4%). On univariate analysis, increasing PF dose (P = 0.002), age >5 years (P = 0.006), and more thorough extent of surgical resection (P = 0.043) were associated with improved RFS; PFRTD (P = 0.20) and SRTD (P = 0.51) were not associated with RFS. On multivariate analysis, although both PF dose (P = 0.004) and extent of surgery (P = 0.045) remained strongly significant, RT duration was now associated with RFS (P = 0.049). Other factors assessed that did not reach significance were patient age, local tumour extent, presence of internal shunt and use of chemotherapy. The importance of local treatment factors was confirmed in this audit with established prognostic factors such as primary tumour macroscopic resection and adequate PF RT dose being associated with RFS. A treatment time effect is weakly suggested, although less significant than RT dose delivered.

Adolescent↗
PubMed2005

Neonatal sepsis in Jamaican neonates.

AIM: To determine the incidence and causative organisms of bacterial sepsis in neonates at The University Hospital of the West Indies. METHODS: A retrospective review of all neonates with culture-proven sepsis admitted to the hospital between January 1995 and December 2000 was conducted. Incidence rates and antimicrobial susceptibility patterns were determined. RESULTS: There were 4702 admissions to the neonatal unit during the study period. Of these, 135 had culture-proven sepsis and 115 were inborn, giving an incidence of 6.7/1000 live births. There were 89 positive blood cultures, 51 positive urine cultures and two positive CSF cultures. The single most common organism was Klebsiella spp (28%). Other organisms included Escherichia coli (16%), group B Streptococcus (11%) and Enterobacter spp (10%). The aminoglycoside resistance rate of Klebsiella spp was 46% and seven isolates had multiple resistance to antibiotics. There was a case fatality rate of 6.7%. CONCLUSION: Physicians involved in newborn care at The University Hospital of the West Indies need to recognise the important role Klebsiella now plays in neonatal sepsis and its contribution to neonatal mortality. Empirical antibiotic regimens for gram-negative sepsis must take into consideration the high rates of aminoglycoside resistance that are now prevalent.

Anti-Bacterial Agents↗
PubMed2005

Student self-assessment in a paediatric objective structured clinical examination.

OBJECTIVE: The objective structured clinical examination (OSCE) has been recognized not only as a useful assessment tool but also as a valuable method of promoting student learning. Student self-assessment is also seen as a means of helping students recognize their strengths and weaknesses, understand the relevance of core learning objectives and to take more responsibility for each stage of their work The authors sought to evaluate the accuracy of medical student self-assessment of their performance in the paediatric clerkship OSCE and thus obtain preliminary data for use in programme strengthening. DESIGN AND METHODS: A self-administered questionnaire was completed by successive groups of students immediately after the OSCE at the end of each clerkship rotation. Students assessed their performance at each station, using a performance rating scale. Performance data were summarized using descriptive and non-parametric tests. Basic statistical analysis of the Likert items was conducted by calculatingfrequencies, means and standard deviations. Regression analysis was used to correlate self-reported rating and actual performance in each station. A p value of < 0.05 was considered significant. Eighty-one students (92%) completed the questionnaire. RESULTS: Fifty-eight (72%) of the students achieved greater than minimum competence in their overall scores. Significant positive correlation (p < 0.05) between student self-rating and actual score was noted- among the following stations: technical skills, cardiovascular examination, assessment of dysmorphism, dermatology, communication and photographic interpretation stations. Students overestimated their performance in the gastrointestinal examination, radiological and arterial blood gas interpretation. Students underestimated their performance in the following: respiratory system, examination of the head, developmental and nutritional assessment. CONCLUSIONS: The findings highlight the perceived strengths and weaknesses in clinical competence and self-assessment skills and provide direction for programme training needs.

Clinical Clerkship↗
PubMed2005

The impact of the establishment of a neonatal intensive care unit on the outcome of very low birthweight infants at the University Hospital of the West Indies.

A retrospective analysis of the outcome of inborn very low birthweight infants admitted to the neonatal unit of the University Hospital of the West Indies pre- (period 1) and post- (period 2) establishment of a neonatal intensive care unit was conducted. During the study, 250 infants were admitted to the neonatal unit, 132 (53%) during period 1 and 118 (47%) during period 2. There was improved survival during period 2 when 81 (69%) infants survived compared to period 1 when 73 (55%) survived (p = 0.02). This increased survival was due to an increase in survival of infants weighing 750-999g in period 2 when 17 (65%) infants survived compared to 9 (29%) in period 1 (p < 0.05). There was an increase in the number of infants ventilated in period 2, 39 (33%) compared to 12 (9%) period 1 (p < 0.001). Infants who were ventilated in period 2 were less likely to die than those ventilated in period 1 (OR 0.05, CI 0.01, 0.66). After controlling for gender, weight, gestational age and ventilation, infants born in the second time period were less likely to die than those born in the first time period (OR 0.33, CI 0.14, 0.76). The establishment of a neonatal intensive care unit has resulted in improved survival of very low birthweight infants; further improvement in survival of these infants will be dependent on increased accessibility to surfactant therapy, initiation of total parenteral nutrition and availability of trained personnel.

Confidence Intervals↗
PubMed2004

[Postmenopausal hormone replacement therapy and cardiovascular risk: role of conjugated equine estrogens and medroxyprogesterone acetate].

Atherosclerosis is a chronic systemic inflammatory disease of the vasculature that accounts for the majority of morbidity and mortality in women. The incidence of atherosclerosis is low in premenopausal women and increases after ovariectomy. Experimental studies demonstrate inhibitory effects of natural estrogens on the progression of atherosclerosis. In contrast, results from recent hormone replacement trials using conjugated equine estrogens and medroxyprogesterone acetate in postmenopausal women showed no effects or even an increase in cardiovascular morbidity and mortality such as thrombosis or stroke. Therefore, conjugated equine estrogens alone or in combination with medroxyprogesterone acetate should not be recommended for the prevention or treatment of cardiovascular disease. Optimizing the risk factor profile such as cessation of smoking, normalizing body weight and blood pressure, regular physical activity, and statin treatment of patients with coronary artery disease remain important treatment options.

Cardiovascular Diseases↗
PubMed2004

Comparison of face-to-face and videoconferenced multidisciplinary clinical meetings.

A trial of videoconferencing of multidisciplinary breast cancer clinical meetings between three public hospitals was conducted in an attempt to increase attendance by medical staff at the meetings, and thus facilitate multidisciplinary care for breast cancer patients. The videoconferences were compared with the previously existing face-to-face clinical meetings through questionnaires, attendance, number of cases discussed and anthropological analysis. Although more people attended the videoconferences than the face-to-face meetings, most of the participants in the trial preferred the face-to-face meetings to the videoconferences. The mean number of cases discussed at the videoconferences was significantly less than the mean number of cases presented at the face-to-face clinical meetings. The face-to-face meetings were informal, spontaneous and conducive to open discussion. In contrast, the videoconferences were formal and regimented. Multidisciplinary case discussion can be facilitated by videoconferencing. Some of the negative experiences we encountered could be overcome with changes in meeting format. Our experience may help others in setting up a successful multidisciplinary team via videoconference.

Breast Neoplasms↗
PubMed2004

Invasive pneumococcal disease in Jamaican children.

A 5-year retrospective review of cases of invasive pneumococcal disease admitted to the Bustamante Hospital for Children, Jamaica was conducted. A total of 111 cases were identified. The estimated incidence of invasive pneumococcal disease in Kingston and St Andrew was 21/100,000 children under the age of 10 years. The majority of cases (76%) were in the under-2-years age group. All four deaths were of infants. Pre-existing medical conditions included sickle cell disease, HIV and undernutrition. The rate of resistance to penicillin was 13.8%. Meningitis accounted for three of the four deaths identified and poor outcome was identified in 28% of cases of meningitis. We conclude that invasive pneumococcal disease causes significant morbidity and mortality in young Jamaican children. Strategies directed at preventing HIV infection and malnutrition and improving the care of children with sickle cell disease and HIV infection would significantly reduce disease incidence.

Anemia, Sickle Cell↗
PubMed2004

Hypernatraemic dehydration in Jamaican breastfed neonates: a 12-year review in a baby-friendly hospital.

A 12-year retrospective review of neonates admitted with hypernatraemic dehydration to the neonatal unit of the University Hospital of the West Indies was conducted between 1 January 1990 and 31 December 2001. Twenty-four infants fulfilled the criteria for hypernatraemic dehydration. Nineteen (79%) women were either nulliparous or primiparous with a mean (SD) age of 26.9 (4.4) yrs. Modal length of hospital stay for mothers was 24 hrs. Twenty (83.3%) infants were exclusively breastfed. Mean (SD) age at presentation was 7.4 (3.8) days. Mean (SD) percentage weight loss between birth and presentation was 18.9% (6.3). Mean (SD) serum sodium at presentation was 164.8 (13.9) mmol/L. Babies visited at home by nurses had a lower mean serum sodium, were less dehydrated and were significantly less acidiotic. Their mean (SD) length of hospital stay was also significantly less [4.2 (1.4) days] than those who were not visited [7.9 (3.8) days] (p < 0.05). Complications occurred in 19 (79%) of infants and included renal failure (19, 79%), seizures (3, 13%) and intraventricular haemorrhage (1, 4%), and one died (4%). Hypernatraemic dehydration is an uncommon complication of failure to establish breastfeeding but is associated with severe morbidity and mortality. Education programmes are needed to increase awareness amongst health-care workers and mothers in order to prevent the problem.

Acidosis↗
PubMed2003

Recent upsurge of tuberculosis in paediatric admissions at the University Hospital of the West Indies.

These case reports describe the clinical course of eight children who were admitted to the University Hospital of the West Indies, Kingston, Jamaica, between July 2000 and November 2001 because of a diagnosis of tuberculosis. This represented an increase in the incidence of the disease in children at this institution. The purpose of this report is to make healthcare workers aware of the resurgence of tuberculosis. The diagnosis of paediatric tuberculosis is challenging and requires a high index of suspicion in the presence of suggestive clinical and laboratory findings. The diagnosis should not be limited to the immunocompromised patient, as in this report the majority of the patients were HIV negative.

Antitubercular Agents↗
PubMed2002

Angiotensin-converting enzyme inhibitor therapy prevents upregulation of endothelin-converting enzyme-1 in failing human myocardium.

In this study, we investigated the role of the renin-angiotensin system in expression of the endothelin system in atrial myocardium of patients with congestive heart failure. Atrial myocardium of control patients without angiotensin-converting enzyme (ACE) inhibitor therapy and heart failure patients without or with ACE inhibitor therapy undergoing aorto-coronary bypass surgery was studied. Endothelin-converting enzyme-1 (ECE-1) expression and endothelin-1 peptide level was upregulated in myocardium of heart failure patients without ACE inhibition. ACE inhibitor therapy prevented upregulation of ECE-1 and endothelin-1 in failing myocardium. Prepro-endothelin-1 and endothelin receptor A expression were not affected by heart failure. Endothelin receptor B was downregulated in heart failure patients. Our data demonstrate an upregulation of ECE-1 mRNA expression in failing human myocardium. Inhibition of the renin-angiotensin system by ACE inhibitor treatment prevents upregulation of ECE-1, suggesting that angiotensin II regulates ECE-1 expression in vivo.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

[Ileus of the small intestine in intestinal marginal-zone B-cell lymphoma of mucoid-associated lymphoid tissue (MALT)].

HISTORY AND ADMISSION FINDINGS: A 67-year-old man had complained of diffuse abdominal pain and constipation for 4 days without indication of any underlying disease. On admission there was no evidence of weight loss, fever or nocturnal sweating. INVESTIGATIONS: Physical examination revealed signs of an acute abdomen with high-pitched bowel sounds and diffuse abdominal guarding. The X-ray showed ileus of the small intestine which required emergency laparotomy. An obstructing conglomerate tumour was present in the area of the ileum, ca. 80 cm proximal to the caecum. It was removed by partial resection of the small intestine. DIAGNOSIS: Ileus of the small intestine with a low-malignant marginal zone B-cell (non-Hodgkin) lymphoma of MALT type (mucoid-associated lymphoid tissue). TREATMENT AND COURSE: Postoperative staging indicated no further manifestation of the lymphoma. As no radical operation in resecting the tumour had been performed, combined radio- and chemotherapy was undertaken. CONCLUSION: Marginal B-cell lymphomas of the small intestine are only rarely seen in central Europe. Despite its usually slow growth this non-Hodgkin lymphoma of low malignancy can produce an acute mechanical ileus without prodromal symptoms. A multimodal therapeutic approach is often employed, but there are no established treatment strategies.

Abdominal Pain↗
PubMed2001

Endothelin and cardiac arrhythmias: do endothelin antagonists have a therapeutic potential as antiarrhythmic drugs?

Endothelin-1 (ET-1), the predominant isoform of the ET peptide family and a potent vasoconstrictor, has been shown to aggravate ischemia-induced ventricular arrhythmias. However, there is also evidence that ET-1 may have a direct arrhythmogenic action that is not solely attributable to myocardial ischemia. Proposed mechanisms for the arrhythmogenic effects of ET-1 are prolongation or increased dispersion of monophasic action potential duration, QT prolongation, development of early afterdepolarizations, acidosis, and augmentation of cellular injury. As for an ionic basis for the observed electrophysiologic effects, ET-induced Ca(2+) release from intracellular stores, generation of inositol triphosphate, inhibition of delayed rectifier K(+) current, and stimulation of the Na(+)/H(+) exchanger may be involved. Recently, some studies have shown that ET receptor antagonists, which promise to be powerful tools in cardiovascular medicine, may also demonstrate antiarrhythmic properties. This review describes the current state of knowledge on the interactions between the ET system and cardiac arrhythmias, and discusses the therapeutic potential of ET antagonists as antiarrhythmic drugs.

Action Potentials↗
PubMed2001

Increased expression of endothelin-1 and inducible nitric oxide synthase isoform II in aging arteries in vivo: implications for atherosclerosis.

We here report that aging increases expression of endothelin-1 and NO synthases in the vasculature and kidney of normotensive rats in vivo. Expression of preproendothelin-1 mRNA was quantified by RT-PCR and in situ hybridization, and endothelin-1 protein was determined by radioimmunoassay/HPLC. Vascular mRNA expression of NO synthase isoforms II and III was analyzed by RT-PCR. In young animals, vascular endothelin-1 protein was differentially expressed (aorta < renal artery < carotid artery) and increased with aging in all vascular beds (P < 0.05). In the intact aorta of aged rats, mRNA expression of preproendothelin-1, "inducible" NO synthase II, and endothelial cell NO synthase III gene was up-regulated (P < 0.05). Moreover, preproendothelin-1 mRNA expression increased in glomeruli and tubulointerstitial cells (P < 0.05). To our knowledge this is the first study demonstrating local vascular up-regulation of the trophic factor endothelin under physiological conditions. Activation of vascular endothelin and NO synthases may be important, pressure-independent factors contributing to structural and functional abnormalities of age-dependent diseases, including atherosclerosis.

Aging↗
PubMed2001

Leaving the meristem behind: regulation of KNOX genes.

The mechanism by which the plant reserves some cells as pluripotent stem cells while partitioning others into differentiated leaf tissue is fundamental to plant development. New work in Arabidopsis elucidates the genetic circuitry that distinguishes meristem from leaf.

Arabidopsis↗
PubMed2001

The therapeutic potential of endothelin receptor antagonists in cardiovascular disease.

Endothelin (ET)-1, a 21-amino acid peptide, is the predominant isoform of the endothelin peptide family. ET-1 is ubiquitously expressed and stimulates vasoconstriction and cell proliferation. Enzymes such as endothelin converting enzymes (ECE), chymases, and non-ECE metalloproteinases contribute to the synthesis of ET-1, which is regulated in an autocrine fashion in vascular and nonvascular cells. Endothelin ET(A) receptors mediate vasoconstriction and cell proliferation, whereas ET(B) receptors are involved in the clearance of ET-1, inhibition of endothelial apoptosis, release of nitric oxide and prostacyclin, and inhibition of ECE-1 expression. Most cardiovascular diseases, such as arterial hypertension, atherosclerosis, restenosis, heart failure, idiopathic cardiomyopathy, pulmonary hypertension, and renal failure are associated with local activation of the endothelin system. Experimental studies and first clinical trials suggest that ET-1 is importantly involved in the functional and structural changes in the cardiovascular system, and that many of the actions of ET-1 are mediated through pressure-independent mechanisms. Endothelin antagonists promise to be successful as a new class of drugs for the treatment of cardiovascular diseases.

Cardiovascular Diseases↗
PubMed2001

Smoking and symbolism: children, communication and cigarettes.

Health promotion, with its concern with empowerment and autonomy, must recognize the agency of its target population. Based on 85 in-depth interviews with 10- to 11-year-old children throughout Northern Ireland, this paper argues that it is necessary to focus on the social relations of children if we are to understand and prevent childhood smoking. Addressing the complex issue of childhood agency, it is argued that regardless of various restrictions to their choices, children can act intentionally in constructing their identities. Instead of viewing the smoking children as communicating with the adult world, we focus on smoking as negotiation of status within the children's culture. Such negotiations utilize symbolism derived from and shared with the 'adult world'. It is important that those analyzing children's lives understand children's ideas and behaviour on their own terms. We must make sure that the very concepts in which the children's experiences are put are appropriate ones. It is suggested that the metaphor 'rite of passage' and terminology such as peer 'pressure' versus adult 'influence', commonly used to analyse the children's smoking behaviour, may actually conceal important aspects of childhood agency.

Attitude to Health↗