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Biomedical subjects

D Maxwell

Publications and source records attributed to D Maxwell.

At least 19 recordsLinked to original sources
PubMed2006

Vaginal delivery can be considered in monochorionic diamniotic twins.

The outcomes of 60 sets of monochorionic diamniotic (MCDA) twins were compared with 218 sets of dichorionic diamniotic (DCDA) twins. The caesarean section rates for MCDA were similar to those for DCDA twins (56.6 versus 53.6%, P > 0.1). Although the number of babies with 5-minute Apgar score of <7 was significantly higher for vaginally delivered MCDA twins compared with that of DCDA twins (12 versus 3.5%, P < 0.001), the umbilical artery pH of <7.2 was similar (20 versus 13%, P > 0.05). Admission to neonatal intensive care unit (NICU) and neonatal mortality were also similar in both groups. Delivery by caesarean section was associated with increased admission to the NICU and neonatal mortality for MCDA twins when compared with vaginal delivery group. From this retrospective cohort study, we can conclude that vaginal delivery for MCDA twins appeared to be a reasonable management option when similar selection criteria for vaginal delivery of DCDA twins were applied.

Adult↗
PubMed2006

A correlation between the shape of the epiglottis and obstructive sleep apnea.

The incidence of Obstructive Sleep Apnea (OSA) is increasing with the rise in the prevalence of obesity in the population. Upon performing esophagogastroduodenoscopy (EGD) on more than 50 patients with BMI ranging from 21 to 63, we noticed an increase in the concavity of the posterior surface of the epiglottis in correlation with the increase in BMI. Since OSA is caused by collapse of the airways, this same pressure seems to be responsible for the deformity of the epiglottis, which normally has a minimally concave posterior surface. Therefore the shape of the epiglottis reflects the degree of airway collapse and thus the severity of OSA. We recommend that patients with increased concavity of the posterior epiglottal surface seen endoscopically should be tested for OSA.

Body Mass Index↗
PubMed2005

Tools of the trade.

An unhurried, deft, economical technique allied to efficient use of available resources, surgical instruments and support staff is the hallmark of a 'good' surgeon. To achieve this sense of fluency, surgeons need to be familiar with the tools of their profession so that these can be employed appropriately for the task at hand. The range of instruments available in obstetrics and gynaecology is no less wide or complex than in any other branch of surgery, but formal teaching in the full range of surgical hardware is frequently lacking and an individual's exposure is generally limited to the instruments used in his or her own training hospital. This chapter sets out to describe key technical areas with which surgeons need to be familiar.

Electrosurgery↗
PubMed2005

The emergency department as an asthma surveillance tool at the community level: a decline in the burden of pediatric asthma in halifax, Canada.

We report pediatric emergency department (PED) asthma visit and inpatient asthma (AS) admission data in our area over a 5-year period. AS visits decreased by 33.9%, AS admissions by 24.6%, both significant compared with the decline in elementary school enrollment. The decrease in asthma visits was due to a decrease in the number of asthmatic patients, not a decline in repeat visits, or use of alternate venues of care. Explanations include a decrease in the burden of disease or an improvement in ambulatory care, but not alternate treatment venues or improvement in acute (PED) care. Readily available, emergency department data are useful in the community surveillance of asthma.

Asthma↗
PubMed2004

Survey of the needs of patients with spinal cord injury: impact and priority for improvement in hand function in tetraplegics.

OBJECTIVE: To investigate the impact of upper extremity deficit in subjects with tetraplegia. SETTING: The United Kingdom and The Netherlands. STUDY DESIGN: Survey among the members of the Dutch and UK Spinal Cord Injury (SCI) Associations. MAIN OUTCOME PARAMETER: Indication of expected improvement in quality of life (QOL) on a 5-point scale in relation to improvement in hand function and seven other SCI-related impairments. RESULTS: In all, 565 subjects with tetraplegia returned the questionnaire (overall response of 42%). Results in the Dutch and the UK group were comparable. A total of 77% of the tetraplegics expected an important or very important improvement in QOL if their hand function improved. This is comparable to their expectations with regard to improvement in bladder and bowel function. All other items were scored lower. CONCLUSION: This is the first study in which the impact of upper extremity impairment has been assessed in a large sample of tetraplegic subjects and compared to other SCI-related impairments that have a major impact on the life of subjects with SCI. The present study indicates a high impact as well as a high priority for improvement in hand function in tetraplegics.

Activities of Daily Living↗
PubMed2002

Association between presence of HLA-B*5701, HLA-DR7, and HLA-DQ3 and hypersensitivity to HIV-1 reverse-transcriptase inhibitor abacavir.

BACKGROUND: The use of abacavir--a potent HIV-1 nucleoside-analogue reverse-transcriptase inhibitor--is complicated by a potentially life-threatening hypersensitivity syndrome in about 5% of cases. Genetic factors influencing the immune response to abacavir might confer susceptibility. We aimed to find associations between MHC alleles and abacavir hypersensitivity in HIV-1-positive individuals treated with abacavir. METHODS: MHC region typing was done in the first 200 Western Australian HIV Cohort Study participants exposed to abacavir. Definite abacavir hypersensitivity was identified in 18 cases, and was excluded in 167 individuals with more than 6 weeks' exposure to the drug (abacavir tolerant). 15 individuals experienced some symptoms but did not meet criteria for abacavir hypersensitivity. p values were corrected for comparisons of multiple HLA alleles (p(c)) by multiplication of the raw p value by the estimated number of HLA alleles present within the loci examined. FINDINGS: HLA-B*5701 was present in 14 (78%) of the 18 patients with abacavir hypersensitivity, and in four (2%) of the 167 abacavir tolerant patients (odds ratio 117 [95% CI 29-481], p(c)<0.0001), and the HLA-DR7 and HLA-DQ3 combination was found in 13 (72%) of hypersensitive and five (3%) of tolerant patients (73 [20-268], p(c)<0.0001 ). HLA-B*5701, HLA-DR7, and HLA-DQ3 were present in combination in 13 (72%) hypersensitive patients and none of the tolerant patients (822 [43-15 675], p(c)<0.0001). Other MHC markers also present on the 57.1 ancestral haplotype to which the three markers above belong confirmed the presence of haplotype-specific linkage disequilibrium, and mapped potential susceptibility loci to a region bounded by C4A6 and HLA-C. Within the entire abacavir-exposed cohort (n=200), presence of HLA-B*5701, HLA-DR7, and HLA-DQ3 had a positive predictive value for hypersensitivity of 100%, and a negative predictive value of 97%. INTERPRETATION: Genetic susceptibility to abacavir hypersensitivity is carried on the 57.1 ancestral haplotype. In our population, withholding abacavir in those with HLA-B*5701, HLA-DR7, and HLA-DQ3 should reduce the prevalence of hypersensitivity from 9% to 2.5% without inappropriately denying abacavir to any patient.

Adult↗
PubMed2002

Spinal lamina I neurones that express neurokinin 1 receptors: II. Electrophysiological characteristics, responses to primary afferent stimulation and effects of a selective mu-opioid receptor agonist.

Intracellular recordings were made from neurones in laminae I and II of the dorsal horn of a longitudinal, parasagittal spinal cord slice from the neonatal rat. Their responses to peripheral nerve stimulation were first tested. Then the responses to bath application of [Sar(9),Met(O(2))(11)]-substance P and [D-Ala(2),N-MePhe(4),Gly-ol(5)]-enkephalin, neurokinin 1 (NK(1)) and mu-opioid receptor agonists respectively, were studied. Finally, the structure of each neurone was investigated by injecting neurobiotin intracellularly following recording, and immunocytochemical studies were performed on post-fixed tissues to reveal whether they expressed the NK(1) receptor. Nine lamina I neurones where shown to express NK(1) receptor and these were depolarised by [Sar(9),Met(O(2))(11)]-substance P. These neurones typically received a powerful C-fibre input that was strongly inhibited, presynaptically, by the mu-opioid receptor agonist.The structure, afferent input, opioid sensitivity and intrinsic properties of these neurones are all consistent with the view that they are a major relay for nociceptive information leading to intense pain. The characteristics of 10 other neurones studied in which the NK(1) receptor was not found to be expressed at levels detectable by immunocytochemistry are briefly described for comparison. These results contribute to the emergent view that the large neurones in the most dorsal neuronal layer (lamina I) of the spinal cord, which express the principal receptor for substance P (NK(1)) over their entire soma and dendrites, are a major relay for information leading to intense pain. Inhibition of the relay of information by these neurones would be predicted to result in analgesia and hence, a detailed knowledge of their unique neurochemical characteristics is of paramount importance.

Action Potentials↗
PubMed2001

Renal function following pregnancy in renal transplant recipients.

We set out to analyse the effect of pregnancy and hypertension in renal transplant recipients and review serum creatinine levels as a marker of graft function, before, during and after pregnancy. The study was conducted at a major tertiary referral centre in London. This was a retrospective analysis of renal transplant patients who had achieved a successful pregnancy. During the period 1967-1998, there have been 272 women of childbearing age with successful renal transplants functioning for over 1 year. Within this population there have been 66 pregnancies in 41 patients resulting in 53 births. Among the pregnancies that progressed beyond 24 weeks, preterm delivery occurred in 32 (60.4%). The mean gestation was 35.7 (range 30-41), mean birth weight was 2365 grams (range 908-3430 grams) with 47%of infants weighing <2500 grams. There were vaginal deliveries in 14 (26%), the rest delivered by caesarean section. Patients that developed hypertension in late pregnancy tended to have higher pre-pregnancy creatinine levels and a deterioration of graft function postpartum. Serum creatinine levels greater than 130 micromol/l before pregnancy predict deteriorating renal function postpartum. Kaplan-Meier life survival analysis showed that the risk of subsequent graft loss is associated with increased serum creatinine levels (130-180 micromol/l) before pregnancy. Pregnancy figures in our unit are favourable compared to those reported in the literature. Poor pre-pregnancy renal function (creatinine 130-180 micromol/l) and previous hypertension is associated with a significant risk of graft failure. Creatinine levels currently deemed as being acceptable during the pregnancy of renal transplant recipients may need to be reappraised.

Journal Article↗
PubMed2001

Late termination for fetal abnormality: providing essential information for parents.

Termination of pregnancy for fetal abnormality in the second half of pregnancy is a distressing experience for parents who are often fearful of the process of termination. Some of this fear may be engendered by a lack of information, and staff caring for couples in this situation may not feel sufficiently sure of the likely course of late termination to answer their questions. There is little existing literature to provide guidance. We studied all late terminations for abnormality occurring in our unit over an 18-month period in order to provide parents and staff with appropriate information.

Journal Article↗
PubMed2001

Screening for trisomy 21: the significance of a positive second trimester serum screen in women screen negative after a nuchal translucency scan.

Screening of pregnancies for trisomy 21 is now an accepted part of antenatal care. Measurement of fetal nuchal translucency in the first trimester and analysis of maternal serum biochemistry in the second trimester are both established methods of screening. The performance characteristics of both tests in an unselected population are well described and the choice of test offered is usually determined by local policy and resources. We present data from a screening programme offering women with a low risk result from nuchal translucency measurement a second trimester serum screen. There were eight cases of trisomy 21 in the 2683 women screened, all of which presented with a high-risk nuchal screen result. Serum screening of 1057 women who screened negative by nuchal translucency gave 46 high-risk results, all of which were, therefore, false positive for trisomy 21. Second trimester biochemistry screening following a negative nuchal translucency screen did not increase the detection of trisomy 21.

Journal Article↗
PubMed2000

Fetal penile length.

OBJECTIVE: To construct a reference range for fetal penile length. METHODS: The length of the penis was measured during ultrasound assessment of 95 structurally normal male fetuses of gestational ages 16-38 weeks. Two fetuses with bladder outflow obstruction were also examined. RESULTS: Fetal penile length increases significantly with gestational age, from a mean value of 6.0 mm at 16 weeks to 26.4 mm at 38 weeks. One fetus with urethral agenesis had a penile length on the 0.3rd centile. CONCLUSIONS: Measurement of the fetal penis is easy and not time-consuming. In cases of bladder outflow obstruction, assessment of penile length assists in the differentiation between urethral agenesis and posterior urethral valves.

Female↗
PubMed1999

Programmes in chronically vulnerable areas: challenges and lessons learned.

In the 'chronically vulnerable areas' (CVAs) of East Africa a smooth linear transition away from emergency programming towards rehabilitation and long-term development is difficult, if not impossible. This makes uncritical application of the 'relief-to-development' continuum to programming unhelpful at best, and perhaps counter-productive. This paper is the result of CARE's efforts to review its own programmes--and those of some of its sister agencies--in chronically vulnerable areas in the East Africa region, to derive important lessons learned and to identify areas where improvements are needed. The paper focuses on strategic considerations and decision-making in relation to entry, programme design and strategies for transition and exit.

Africa, Eastern↗
PubMed1996

Esophageal and duodenal atresia in a fetus with Down's syndrome: prenatal sonographic features.

Ultrasound examination of a 22-week fetus demonstrated a grossly distended stomach and proximal duodenum, with a large cystic area in the chest. There was associated polyhydramnios. A presumptive diagnosis of duodenal atresia with a congenital diaphragmatic hernia was made. Analysis of a fetal blood sample showed that the fetus had Down's syndrome. Histological examination after termination of the pregnancy revealed the unusual combination of duodenal and esophageal atresia, with an intact diaphragm.

Adult↗
PubMed1996

Estimation of fetal lung volume using enhanced 3-dimensional ultrasound: a new method and first result.

OBJECTIVE: To measure fetal lung volume using a computer based, enhanced, 3-dimensional ultrasound imaging system. DESIGN: An observational study. SETTING: The Fetal Medicine Unit at Guys Hospital, London. PARTICIPANTS: Twenty healthy women with a singleton pregnancy between 24 and 36 weeks of gestation were scanned on one occasion during pregnancy using an ultrasound based 3-dimensional imaging system. All delivered at term with weights above the 10th centile for gestation. RESULTS: Total lung volume increased exponentially with gestational age. Right lung volume measured consistently greater than left lung volume. CONCLUSIONS: The use of this new enhanced 3-dimensional imaging system allows for estimations of fetal lung volume. Preliminary data confirm that fetal lung volume, measured by a computerised 3-dimensional ultrasound imaging system increased exponentially with gestational age. The use of this system has obvious application in the further study of lung growth in utero and possible clinical application in disease states where fetal lung growth may be impaired.

Female↗
PubMed1996

A new lethal chondrodysplasia with platyspondyly, long bone angulation and mixed bone density.

A fetus diagnosed by sonography at 20 weeks' gestation had multiple skeletal abnormalities. The main features were absent ossification of the skull and cervical and upper thoracic vertebral bodies; short, angulated femora, tibiae, radii and ulnae but normal humeri; platyspondyly; trident-shaped acetabular roofs; sclerotic bands on the iliac wings and scapulae; clavicular hooks; and overall, mixed bone density. We suggest that this is a new chondrodysplasia which, since the parents are first cousins, could follow autosomal recessive inheritance.

Abnormalities, Multiple↗