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Biomedical subjects

M L Hughes

Publications and source records attributed to M L Hughes.

At least 19 recordsLinked to original sources
PubMed2004

Pancreatic hamartoma.

Pancreatic hamartoma is a rare benign lesion and may be mistaken for a malignancy, as demonstrated by two cases. The first case was a 29-year-old man who presented with a 7-month history of intermittent upper abdominal pain, nausea and vomiting and a 15-kg weight loss. CT and MRI revealed a mass in the head of the pancreas. The second case was a 62-year-old man who presented with a 2-year history of intermittent abdominal pain, vomiting and a 25-kg weight loss. Although positron emission tomography was normal, CT revealed thickening of the duodenal wall and endoluminal ultrasonography revealed a tumour in the head of the pancreas. Both patients recovered from uneventful Kausch-Whipple pancreatoduodenectomy (in the first patient, it was pylorus-preserving), and in each case the histological diagnosis was hamartoma. Pancreatic hamartoma can present with vague, non-specific symptoms which, despite modern diagnostic tools, can be difficult to diagnose. Surgical resection with histopathological examination is required to confirm the diagnosis.

Adult↗
PubMed2004

Major resection for chronic pancreatitis in patients with vascular involvement is associated with increased postoperative mortality.

BACKGROUND: The aim was to evaluate the outcome of major resection for chronic pancreatitis in patients with and without vascular involvement. METHODS: Of 250 patients with severe chronic pancreatitis referred between 1996 and 2003, 112 underwent pancreatic resection. The outcome of 17 patients (15.2 per cent) who had major vascular involvement was compared with that of patients without vascular involvement. RESULTS: The 95 patients without vascular involvement had resections comprising Beger's operation (39 patients), Kausch-Whipple pancreatoduodenectomy (28), total pancreatectomy (25) and left pancreatectomy (three). Twenty-five major vessels were involved in the remaining 17 patients. One or more major veins were occluded and/or compressed producing generalized or segmental portal hypertension, and three patients also had major arterial involvement. Surgery in these patients comprised Beger's operation (eight), total pancreatectomy (five), Kausch-Whipple pancreatoduodenectomy (two) and left pancreatectomy (two). Perioperative mortality rates were significantly different between the groups (two of 95 versus three of 17 respectively; P = 0.024). There were similar and significant improvements in long-term outcomes in both groups. CONCLUSION: Resection for severe chronic pancreatitis in patients with vascular complications is hazardous and is associated with an increased mortality rate. Vascular assessment should be included in the routine follow-up of patients with chronic pancreatitis, to enable early identification of those likely to develop vascular involvement and prompt surgical intervention.

Adolescent↗
PubMed2004

Improved early ventricular performance with a right ventricle to pulmonary artery conduit in stage 1 palliation for hypoplastic left heart syndrome: evidence from strain Doppler echocardiography.

OBJECTIVE: To quantify non-invasively right ventricular (RV) performance in infants after stage 1 palliation for hypoplastic left heart syndrome (HLHS). DESIGN: Prospective, observational study with two dimensional and strain Doppler echocardiography. SETTING: Single tertiary paediatric cardiology centre. PATIENTS: Convenience sample of nine consecutive infants with HLHS. Four whose surgery involved a systemic to pulmonary artery (S-PA) shunt were compared with five whose surgery incorporated a right ventricle to pulmonary artery (RV-PA) conduit. METHODS: Basal RV free wall longitudinal strain rate, systolic strain (epsilon), and RV percentage area change were calculated during a single assessment between 27-50 days after surgery. RESULTS: Cardiopulmonary bypass time was longer in patients who underwent RV-PA (226 (30) minutes v 181 (18) minutes, p = 0.03), but cross clamp time, duration of ventilation, and inotrope use did not differ. Two patients in the S-PA group died, on days 29 and 60 after surgery. Peak systolic strain rate (-1.24 (0.19)/s v -0.91 (0.21)/s, p = 0.048), peak epsilon (-17.8 (1.8)% v -13.4 (2.0)%, p = 0.01), and RV percentage area change (56 (6)% v 25 (6)%, p < 0.01) were all greater among RV-PA patients. These indices also tended to be greater in survivors as a group. Ventricular loading conditions (oxygen saturations, diuretic treatment, and blood pressure) were similar in both groups. CONCLUSION: Strain Doppler echocardiography shows improved RV longitudinal systolic contractility in patients during convalescence after the RV-PA modification of stage 1 palliation for HLHS compared with those with an S-PA shunt.

Anastomosis, Surgical↗
PubMed2003

Minimally invasive retroperitoneal pancreatic necrosectomy.

INTRODUCTION: Open surgery for pancreatic necrosis is associated with considerable morbidity and mortality. We report the results of a recently developed minimally invasive technique that we adopted in 1998. METHODS: A descriptive explanation of the approach is given together with the results of a retrospective analysis of patients who underwent a minimally invasive retroperitoneal pancreatic necrosectomy (MIRP) between August 1998 and April 2002. PATIENTS: There were 24 patients with a median (range) age of 61 (29-75) years. The initial median (range) APACHE II score was 8 (2-21). All patients had infected pancreatic necrosis with at least 50% pancreatic necrosis. In three patients it was not possible to complete the first MIRP because of technical reasons. RESULTS: A total of 88 procedures were performed with a median (range) of 4 (0-8) per patient. Twenty-one (88%) patients developed 36 complications during the course of their illness. Five patients required an additional open procedure: 2 for subsequent distant collections, 2 for bleeding and 1 for persisting sepsis and a distant abscess. Six (25%) patients who had MIRP died. The median (range) post-operative hospital stay was 51 (5-200) days. CONCLUSIONS: MIRP is a new technique that has shown promising results, and could be preferable to open pancreatic necrosectomy in selected patients. However, unresolved issues remain to be overcome and the exact role of MIRP in the management of pancreatic necrosis has yet to be defined.

Adult↗
PubMed2002

Prospective comparison of costs and short term health outcomes of surgical versus device closure of atrial septal defect in children.

OBJECTIVE: To compare surgical and device closure of isolated secundum atrial septal defect (ASD) in terms of hospital costs, clinical outcome, and impact on the patient and family. DESIGN: Prospective, observational study. SETTING: Paediatric tertiary referral centre. PATIENTS: Consecutive local children with a secundum ASD, admitted between 1 May 1999 and 1 May 2001. METHODS: Parents completed a standardised questionnaire at recruitment (on admission), at discharge, and one month after the procedure. Clinical and hospital generated cost data were collated at discharge. RESULTS: 62 children were included in the analysis: 19 who underwent surgical repair and 43 who underwent device closure with the Amplatzer septal occluder. Median procedure times and hospital stay were significantly longer for surgical patients (170 (147 to 180) v 92 (70 to 115) minutes and 88 (78 to 112) v 29 (28 to 30) hours, respectively; p < 0.01). There was no difference in the complication rate. No device patients required intensive care or blood products. The median values for postoperative pain score, analgesia use, and convalescence time were greater for surgical patients. The median cost of each procedure was similar, but higher nursing and laboratory costs contributed to a slightly greater total cost for surgical repair (Aus$12 969 ($11 569 to $14 215) v Aus$11 845 ($10 669 to $12 555), p = 0.03). CONCLUSIONS: Device closure of ASD involves a shorter hospital stay, causes less discomfort and familial disturbance, and carries less cost than surgical closure. However, there should be guarded acceptance of this technique until long term data are available.

Adolescent↗
PubMed2001

Evidence for a susceptibility locus on chromosome 6q influencing phonological coding dyslexia.

A linkage study of 96 dyslexia families containing at least two affected siblings (totaling 877 individuals) has found evidence for a dyslexia susceptibility gene on chromosome 6q11.2-q12 (assigned the name DYX4). Using a qualitative phonological coding dyslexia (PCD) phenotype (affected, unaffected, or uncertain diagnoses), two-point parametric analyses found highly suggestive evidence for linkage between PCD and markers D6S254, D6S965, D6S280, and D6S251 (LOD(max) scores = 2.4 to 2.8) across an 11 cM region. Multipoint parametric analysis supported linkage of PCD to this region (peak HLOD = 1.6), as did multipoint nonparametric linkage analysis (P = 0.012). Quantitative trait linkage analyses of four reading measures (phonological awareness, phonological coding, spelling, and rapid automatized naming speed) also provided evidence for a dyslexia susceptibility locus on chromosome 6q. Using a variance-component approach, analysis of phonological coding and spelling measures resulted in peak LOD scores at D6S965 of 2.1 and 3.3, respectively, under 2 degrees of freedom. Furthermore, multipoint nonparametric quantitative trait sibpair analyses suggested linkage between the 6q region and phonological awareness, phonological coding, and spelling (P = 0.018, 0.017, 0.0005, respectively, for unweighted sibpairs < 18 years of age). Although conventional significance thresholds were not reached in the linkage analyses, the chromosome 6q11.2-q12 region clearly warrants investigation in other dyslexia family samples to attempt replication and confirmation of a dyslexia susceptibility gene in this region.

Adolescent↗
PubMed2001

A longitudinal study of electrode impedance, the electrically evoked compound action potential, and behavioral measures in nucleus 24 cochlear implant users.

OBJECTIVE: The primary goal of this study was to examine changes that may occur in electrode impedance, electrically evoked compound action potential (EAP) threshold and slope of the EAP growth function, and behavioral measures of threshold T-level) and maximum comfort (C-level) over time in both adult and child cochlear implant users. Secondary goals were to determine whether changes in these measures are consistent between children and adults, and to determine whether behavioral measures (MAP T- and C-levels) and electrophysiologic measures (EAP thresholds) exhibit the same trends over time. DESIGN: Thirty-five children and 33 adults implanted with the Nucleus CI24M between November 1996 and August 1999 participated in this study. Subjects were included in this study if 1) they had used their implant for at least 1 yr after device connection, and 2) they had participated in the necessary data collection at a minimum number of the time intervals assessed in this study. EAP threshold, slope of the EAP growth function, and common ground electrode impedance measures were collected intraoperatively, at initial stimulation, and at several subsequent visits up to 2 yr post initial stimulation. MAP T- an d C-levels weremeasured at initial stimulation and at the same time intervals as described above. RESULTS: Changes in electrode impedance, EAP thresholds, and slope of the EAP growth function from measures made intraoperatively, at initial stimulation, and at 1 to 2 mo post initial stimulation were similar in both children and adults. Beyond the 1- to 2-mo visit, children exhibited significant increases in electrode impedance, EAP thresholds, slope, and MAP T-levels, whereas these samemeasures in adults remained relatively stable. EAP thresholds in children stabilized by the 3- to 8-mo visit, and electrode impedance stabilized by the 6- to 8-mo visit, while slope of the EAP growth function, MAP T-levels,and MAP C-levels werestable by 1 yr post initial stimulation. C-levels in adults increased up to 1 yr post initial stimulation; however, the amount of increase was much smaller than that seen in children. In both children and adults, longitudinal trends in EAP thresholds mirrored T-level more closely than C-level. CONCLUSIONS: The results of this study suggest that peripheral changes occur in many children that do not generally occur in adults within the first year of cochlear implant use. One implication of these results is that if EAP thresholds are to be used to assist in programming the speech processor for children, it is best to make those measures at the same time interval as device programming rather than using measures made intraoperatively or at the initial programming session to set MAP levels at later visits.

Acoustic Impedance Tests↗
PubMed2001

Molecular quantification of human beta-glucuronidase levels in a patient with Vohwinkel's syndrome.

The skin must undergo the process of keratinization in order to perform its functions. During the process of differentiation, certain genes are activated while others are repressed, leading to changes in structural proteins and enzymes and in the synthesis of various lipids. An error in any of these steps can ultimately impair the process of keratinization. Vohwinkel's syndrome is the direct result of a defect in keratinization. Patients who have this epidermolytic palmoplantar keratoderma present clinically with hyperkeratosis of the stratum corneum. Hyperkeratosis has been linked to an increase in beta-glucuronidase levels. The authors studied the absolute concentration of human beta-glucuronidase in a patient with Vohwinkel's syndrome as determined through a double-antibody sandwich enzyme-linked immunosorbent assay and a Western blot assay of the blood, urine, and skin of the patient.

Adult↗
PubMed2000

Postprandial decrease in splenic volume demonstrated by magnetic resonance imaging and stereology.

The aim of this study was to determine if the volume of the spleen changes after food intake. We applied an unbiased and efficient method for splenic volume estimation using magnetic resonance imaging (MRI) in combination with modern design stereology. MR images of the spleen were obtained for 10 healthy volunteers (five men and five women; mean age 28.9 years [range 23-35 years]) without a history of splenomegaly. The initial scans were performed in the morning after overnight fasting. Each volunteer then consumed a standard balanced meal weighing 500 g [2,460 kJ (627 kcal) energy] with 500 ml of still mineral water. Second identical MR scans were performed approximately 1 hr later. Postprandially, splenic volume decreased by an average of 6.6% (P = 0.005), probably due to increased splanchnic blood flow after food intake.

Adult↗
PubMed2000

Pulmonary vascular resistance and reactivity in children with end-stage cardiomyopathy.

Pulmonary vascular resistance (PVR) and reactivity were compared in 63 children with end-stage cardiomyopathy (CM) referred for cardiac transplantation. Diagnostic category of CM was the sole determinant of PVR. Compared with other patients, children with restrictive CM were younger at diagnosis and had a significantly higher pulmonary vascular resistance index (PVRI). Children with a baseline PVRI of up to 11.8 units per meter squared (U.m(2)) who showed reactivity underwent successful orthotopic cardiac transplantation.

Adolescent↗
PubMed2000

Obesity in women from developing countries.

OBJECTIVES: The key objective was to estimate obesity (>/=30 kg/m2) in women 15-49 y from developing countries. A second objective was to study how obesity varies by educational level and by residence in urban and rural areas. A third objective was to investigate how national incomes shape the relationship between obesity and eduction or residence. DESIGN: The analyses use cross-sectional data from nationally representative surveys from developing countries carried out in the last decade. Most of the surveys were Demographic Health Surveys (DHS). Data from a survey from the USA are used for comparison. SETTING: The 39 surveys used come from 38 developing countries and the USA. SUBJECTS: A total of 147,938 non-pregnant women 15-49 y were included in the analyses. RESULTS: The percentage of obese women was 0.1% in South Asia, 2.5% in Sub-Saharan Africa, 9. 6% in Latin America and the Caribbean, 15.4% in Central Eastern Europe/Commonwealth of Independent States (CEE/CIS), 17.2% in the Middle East and North Africa, and 20.7% in the USA. Levels of obesity in countries increased sharply until a gross national product of US$1500 per capita (1992 values) was reached and changed little thereafter. In very poor countries, such as in Sub-Saharan Africa, obesity levels were greatly concentrated among urban and higher educated women. In more developed countries, such as those in Latin America and the CEE/CIS regions, obesity levels were more equally distributed in the general population. CONCLUSIONS: Based on the analyses presented and on a review of the literature, it is concluded that obesity among women is a serious problem in Latin America and the Caribbean, the Middle East and North Africa, and the CEE/CIS region. Obesity is less of a concern in Sub-Saharan Africa, China and South Asia. Obesity levels increased over time in most of the limited number of countries with data, but at varying rates. Rising national incomes in developing countries and increased 'Westernization' will most likely lead to increased levels of obesity in the future. SPONSORSHIP: Financial support was provided by the Food and Nutrition Program of the Pan American Health Organization and by the World Bank.

Adolescent↗
PubMed2000

Overweight and obesity in preschool children from developing countries.

OBJECTIVES: To estimate levels and trends in overweight and obesity in preschool children from developing countries; to study how overweight varies by the educational level of the mother, by urban or rural residence, and by gender; to investigate how these relationships are related to the gross national product (GNP). DESIGN: 71 national nutrition surveys since 1986 from 50 countries were used. SUBJECTS: 150,482 children 12 to 60 months from the most recent survey from each country were the primary sample. MEASUREMENTS: Overweight and obesity were defined as weight-for-height (>1 or >2 s.d., respectively) of the WHO/NCHS reference curves. Stunting was <-2 s.d. of the same reference. Urban was as defined in each of the surveys and higher education was defined as at least one year of secondary schooling or higher. RESULTS: 32 of 50 countries had a prevalence of obesity below 2.3%, the value in the reference population. The prevalences of overweight and obesity were lowest in Asia and in Sub-Saharan Africa. In 17 countries with serial data, no consistent regional trends could be detected. Overweight was more common in urban areas, in children of mothers with higher education, and in girls; these relationships did not differ by GNP but GNP was related negatively to stunting and positively to overweight. CONCLUSIONS: Obesity does not appear to be a public health problem among preschool children in Asia and Sub-Saharan Africa. In a number of countries in Latin America and the Caribbean, the Middle East and North Africa, and the region of Central Eastern Europe/Commonwealth of Independent States, levels are as high as in the United States.

Child Welfare↗
PubMed2000

The relationship between EAP and EABR thresholds and levels used to program the nucleus 24 speech processor: data from adults.

OBJECTIVE: The objective of this study was to determine the relationship between electrically evoked whole nerve action potential (EAP) and electrical auditory brain stem response (EABR) thresholds and MAP threshold (T-level) and maximum comfort level (C-level) for subjects who use the Nucleus 24 cochlear implant system. DESIGN: Forty-four adult Nucleus 24 cochlear implant users participated in this study. EAP thresholds were recorded using the Neural Response Telemetry System developed by Cochlear Corporation. EABR thresholds were measured for a subset of 14 subjects using standard evoked potential techniques. These physiologic thresholds were collected on a set of five electrodes spaced across the cochlea, and were then compared with behavioral measures of T-level and C-level used to program the speech processor. RESULTS: EAP thresholds were correlated with MAP T- and C-levels; however, the correlation was not strong. A technique for improving the correlation by combining measures of T- and C-levels made on one electrode with the EAP thresholds was presented. Correlations between predicted and measured T- and C-levels using this technique were 0.83 and 0.77, respectively. Similar results were obtained using the EABR thresholds for a smaller set of subjects. In general, EABR thresholds were recorded at levels that were approximately 4.7 programming units lower than EAP thresholds. CONCLUSIONS: Either EAP or EABR thresholds can be used in combination with a limited amount of behavioral information to predict MAP T- and C-levels with reasonable accuracy.

Acoustic Stimulation↗
PubMed2000

Comparison of EAP thresholds with MAP levels in the nucleus 24 cochlear implant: data from children.

OBJECTIVE: The purpose of this study is to examine the relationship between the electrically evoked compound action potential (EAP) thresholds and the MAP thresholds (T-levels) and maximum comfort levels (C-levels) in children implanted with the Nucleus 24 device. DESIGN: EAP thresholds were measured using the Neural Response Telemetry system of the Nucleus 24 device. Twenty children implanted with the Nucleus 24 cochlear implant participated in this study. EAP thresholds were compared with the behavioral measures of T- and C-level used to construct the MAP these children used on a daily basis. For these subjects, both EAP and MAP T- and C-levels were obtained the same visit, which occurred at 3 to 5 mo postconnection. RESULTS: EAP thresholds were shown to fall between MAP T- and C-level for 18 of 20 subjects tested; however, considerable variability across subjects was noted. On average, EAP thresholds fell at 53% of the MAP dynamic range. Correlations between EAP threshold and MAP T- and C-level improved substantially when combined with behavioral measures obtained from one electrode in the array. CONCLUSIONS: Moderate correlations were found between EAP thresholds and MAP T- and C-levels for the children participating in this study. However, a technique is described for improving the accuracy of predictions of MAP T- and C-levels based on EAP data combined with a small amount of behavioral information.

Acoustic Stimulation↗
PubMed2000

Electrically evoked compound action potentials recorded from subjects who use the nucleus CI24M device.

The ability to directly measure the response to a pulse with the NRT opens the possibility of using this system to characterize the responses to more complex stimuli. An example is the responses to constant-amplitude pulse trains. With further changes in the software that controls the implant, it may be possible to characterize the responses to modulated pulse trains or other stimuli that better approximate the type of stimuli that are normally used with a cochlear implant speech processor.

Action Potentials↗
PubMed1999

Summary of results using the nucleus CI24M implant to record the electrically evoked compound action potential.

OBJECTIVE: This study outlines a series of experiments using the neural response telemetry (NRT) system of the Nucleus CI24M cochlear implant to measure the electrically evoked compound action potential (EAP). The goal of this investigation was to develop a protocol that allows successful recording of the EAP in a majority of CI24M cochlear implant users. DESIGN: Twenty-six postlingually deafened adults participated in this study. A series of experiments were conducted that allowed us to examine how manipulation of stimulation and recording parameters may affect the morphology of the EAP recorded using the Nucleus NRT system. RESULTS: Results of this study show consistent responses on at least some electrodes from all subjects. Cross-subject and cross electrode variations in both the growth of the response and the temporal refractory properties of the response were observed. The range of stimulus and recording parameters that can be used to record the EAP with the Nucleus NRT system is described. CONCLUSIONS: Using the protocol outlined in this study, it is possible to reliably record EAP responses from most subjects and for most electrodes in Nucleus CI24M cochlear implant users. These responses are robust and recording these responses does not require that the subject sleep or remain still. Based on these results, a specific protocol is proposed for measurement of the EAP using the NRT system of the CI24M cochlear implant. Potential clinical implications of these results are discussed.

Adult↗