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Biomedical subjects

W Doyle

Publications and source records attributed to W Doyle.

At least 19 recordsLinked to original sources
PubMed2001

Late seizure recurrence after multiple subpial transections.

We studied long-term outcome (range, 28-89 months; mean, 56 months) after multiple subpial transections (MST) for medically refractory epilepsy. Forty-three (79.6%) of 54 patients had a consistent significant reduction in seizure frequency, and 27 (50%) of the 54 were either entirely seizure free or virtually so. However, 10 (18.5%) patients sustained an increase in seizure frequency several years after surgery, after showing initial postoperative improvement. This suggests that late seizure recurrence is a more important problem in cases in which MST has been performed than for pure resections.

Cerebral Cortex↗
PubMed2001

Inter-pregnancy folate and iron status of women in an inner-city population.

The purpose of the present study was to evaluate whether micronutrient supplementation improved the nutritional status of women with poor diets during the inter-pregnancy interval. Fifty-five women who had given birth to a low birth weight baby (<2.5 kg), and who planned to have a further pregnancy, were recruited to a prospective randomised study in East London, UK. Of the fifty-five mothers recruited, forty-four (78 %) met fewer than four of sixteen dietary reference values according to the information provided in a 7 d diet diary, and were categorised as having an 'inadequate' diet. Half of the mothers in the 'inadequate'-diet group were randomly assigned to receive a micronutrient and a single cell oil supplement containing docosahexaenoic acid. All participants received dietary advice based on analysis of their diet diaries, and general lifestyle advice on preparing for pregnancy. Mothers had a blood sample taken at 3 and 9 months post-partum to measure their folate, Fe stores and fatty acid status. Mean serum and erythrocyte folate levels increased significantly between 3 and 9 months post-partum in both the adequate-diet group and the supplemented group. At 9 months post-partum, over half of the unsupplemented, inadequate-diet group remained severely deficient in folate (serum folate <230 nmol/l) and had low serum ferritin levels (<15 microg/l). The high prevalence of inadequate diets in this inner-city population and the low motivation of women to participate in a nutrition programme suggests that consideration should be given to the provision of free folate and Fe supplements to all women in this and similar populations, or at least to women who have delivered a low birth weight baby, who plan further pregnancies.

Adolescent↗
PubMed2000

Laboratory scaledown of protein purification processes involving fractional precipitation and centrifugal recovery.

The ability to predict the performance of large-scale processes is central to the rapid development of successful operations at the pilot and industrial scale. In this article, we examine the operation, at laboratory scale, of precipitation reactors and centrifuges for protein precipitate recovery and dewatering and how they might best mimic large-scale reactors and centrifuges, in this case, a pilot-scale batch stirred-tank reactor and a multichamber-bowl centrifuge. Novel approaches to bench-top centrifuge operation are provided, in particular with a view to delivery of material for subsequent high-resolution purification, which would be obtained at full pilot scale. Results are presented in terms of properties of the protein precipitates, the fraction of solids recovered, and the extent of dewatering achieved. Good agreement was obtained at bench scale (a 1000-fold scale down factor) for all of these parameters for pilot-scale, batch-feed operation. In addition, the methodology developed allows identification of the extent of break-up that occurs in continuous-feed centrifuges when processing shear-sensitive materials such as the protein precipitates studied here.

Alcohol Dehydrogenase↗
PubMed2000

Relation of cortical language distribution and cognitive function in surgical epilepsy patients.

PURPOSE: To investigate the relation between the number and spatial distribution of language sites and specific patient-and epilepsy-related variables. METHODS: Patients with stimulation-induced reading or naming errors from anterior or inferior temporal cortex (i.e., atypical temporal language sites) were compared with those with language sites confined to Wernicke's area (WA) in the posterosuperior temporal and inferior parietal perisylvian area. In a consecutive series of 44 left hemisphere language dominant patients with complex partial seizures before left temporal lobectomy, correlations were compared between cortical language distribution and measures of cognitive function. RESULTS: Patients with atypical temporal language sites (group 1) had significantly fewer years of education that did patients with language sites in WA (group 2). Patients in group 1 had poorer verbal learning and fluency than did patients in group 2. Patients with IQ <80 were significantly more likely to have multiple sites where stimulation disrupted language than did patients with normal IQ. Number of language sites had significant negative correlations with full-scale IQ, and measures of confrontation naming, verbal fluency, and immediate verbal memory. CONCLUSIONS: Language cortex has a wider spatial distribution in epilepsy surgery patients with lower intelligence, poorer education, and worse verbal and memory skills.

Adult↗
PubMed1999

Micronutrients: highlights and research challenges from the 1994-5 National Diet and Nutrition Survey of people aged 65 years and over.

The aims of the National Diet and Nutrition Survey series are summarized, and the new National Diet and Nutrition Survey of people aged 65 years and over is explored, with particular emphasis on micronutrient intakes and status indices. Mean nutrient intakes were generally satisfactory for most micronutrients, but intakes of vitamin D, Mg, K and Cu were low. Intakes of vitamin D were far below the reference nutrient intake for people aged 65 years and over, and there was also biochemical evidence of vitamin D deficiency, for 8% of free-living and 37% of institution participants, attributed partly to limited exposure to sunlight. A substantial proportion of people living in institutions had inadequate biochemical status indices, notably for vitamin C, Fe and folate. Relationships between intake and status were close for vitamins. Mineral intakes did not correlate well with currently used status indices. Some intakes and indices, especially those of vitamin C, carotenoids, Na and K, were strongly correlated with socio-economic status and with north-south gradients in Britain. Future research challenges should address the functional and health significance of low intakes and sub-optimal biochemical indices for certain micronutrients, especially for people living in institutions; the shortcomings of mineral status indices especially as indicators of mineral intake; the social and geographical inequalities of micronutrient intakes and status, and why micronutrient status deteriorates with increasing age. The answers to these questions will help to define the characteristics of nutritional risk for older people in Britain, and to clarify future needs for education and intervention.

Aged↗
PubMed1999

Iron deficiency in older people: interactions between food and nutrient intakes with biochemical measures of iron; further analysis of the National Diet and Nutrition Survey of people aged 65 years and over.

OBJECTIVE: To quantitatively investigate relationships between food consumption, nutrient intake and biochemical markers of iron status in a population of older people. DESIGN: National Diet and Nutrition Survey: cross-sectional survey of a nationally representative population of men and women aged 65 y and over. SETTING: Mainland Great Britain SUBJECTS: 1268 participants (651 men and 617 women) who provided both dietary intake and blood biochemistry. 986 were living in private households and 282 were living in residential or nursing homes. RESULTS: Intakes of alcohol, vitamin C, protein, haem and non-haem iron and fibre were positively associated with iron status. Consumption of meat, poultry and fish were positively associated with six measures of iron status, and vegetables and potatoes with four measures. Calcium, dairy foods and tea generally had a negative association with most measures of iron status. CONCLUSIONS: A varied diet containing meat, poultry and fish, vegetables and fruit, with a moderate intake of alcohol will make a positive contribution to the iron status of elderly people.

Aged↗
PubMed1999

Function-specific high-probability "nodes" identified in posterior language cortex.

PURPOSE: Posterior, "Wenicke's," language areas have a high degree of between-subject variability, as shown by electrical-stimulation mapping. We investigated the possibility of an organized structure in the distribution of posterior language areas. METHODS: Extraoperative subdural grid stimulation was performed on 67 left hemisphere-dominant patients before resective epilepsy surgery during counting, naming, and reading. Intersubject-averaged language maps were generated in which stimulation disrupted only one language function and not the others, or combinations of language functions. RESULTS: Language sites, although highly variable between subjects, were not organized randomly and appeared to be arranged into several focal, non-contiguous, higher probability "nodes" devoted to different aspects of language processing. Speech-arrest sites were concentrated in classic Wernicke's area. Areas where stimulation induced only reading errors were found in the posterior middle temporal gyrus and the inferior parietal lobule. These regions may correspond with an orthographic input lexicon. Areas eliciting only naming errors were found in the posterior inferior temporal gyrus extending into the mid-middle temporal gyrus and may represent a visual-representation input lexicon. Sites where stimulation elicited errors in both naming and reading were more variable in location than sites devoted to only one function, extended farther anteriorly along the temporal neocortex, and may correspond with a semantic lexicon. CONCLUSIONS: The existence of high-probability nodes in posterior language cortex supports a modality-specific modular architecture and the possibility of a conserved, universal structure.

Adolescent↗
PubMed1998

Increased interleukin-6 levels in nasal lavage samples following experimental influenza A virus infection.

Interleukin-6 (IL-6) is a pleotropic cytokine implicated in the pathogenesis of local inflammation during viral upper respiratory infections. This study determined if experimental influenza A virus infection causes local IL-6 production. Seventeen healthy, adult subjects were intranasally inoculated, by course drops, with a safety-tested strain of influenza A/Kawasaki/86 (H1N1) virus. Nasal lavage samples were collected, symptoms were recorded, and expelled nasal secretions were weighed once before and then daily for 8 days after the virus inoculation. Lavage samples were submitted for virus culture and were examined for IL-6 and IL-4 by enzyme-linked immunosorbent assay. The IL-6, but not IL-4, levels were significantly increased in the nasal lavage samples of the 12 subjects who shed virus but not in those of the 5 subjects who did not shed virus. Moreover, the elevations in IL-6 levels were related temporally to the development of nasal symptoms and secretions but not to systemic symptoms. These results suggest a role for locally produced IL-6 in the pathogenesis and expressed symptomatology of influenza A virus infection.

Adult↗
PubMed1998

Preoperative predictors of anterior temporal language areas.

OBJECT: Although it is known that 5 to 10% of patients have language areas anterior to the rolandic cortex, many surgeons still perform standard anterior temporal lobectomies for epilepsy of mesial onset and report minimal long-term dysphasia. The authors examined the importance of language mapping before anterior temporal lobectomy. METHODS: The authors mapped naming, reading, and speech arrest in a series of 67 patients via stimulation of long-term implanted subdural grids before resective epilepsy surgery and correlated the presence of language areas in the anterior temporal lobe with preoperative demographic and neuropsychometric data. Naming (p < 0.03) and reading (p < 0.05) errors were more common than speech arrest in patients undergoing surgery in the anterior temporal lobe. In the approximate region of a standard anterior temporal lobectomy, including 2.5 cm of the superior temporal gyrus and 4.5 cm of both the middle and inferior temporal gyrus, the authors identified language areas in 14.5% of patients tested. Between 1.5 and 3.5 cm from the temporal tip, patients who had seizure onset before 6 years of age had more naming (p < 0.02) and reading (p < 0.01) areas than those in whom seizure onset occurred after age 6 years. Patients with a verbal intelligence quotient (IQ) lower than 90 had more naming (p < 0.05) and reading (p < 0.02) areas than those with an IQ higher than 90. Finally, patients who were either left handed or right hemisphere memory dominant had more naming (p < 0.05) and reading (p < 0.02) areas than right-handed patients with bilateral or left hemisphere memory lateralization. Postoperative neuropsychometric testing showed a trend toward a greater decline in naming ability in patients who were least likely to have anterior language areas, that is, those with higher verbal IQ and later seizure onset. CONCLUSIONS: Preoperative identification of markers of left hemisphere damage, such as early seizure onset, poor verbal IQ, left handedness, and right hemisphere memory dominance should alert neurosurgeons to the possibility of encountering essential language areas in the anterior temporal lobe (1.5-3.5 cm from the temporal tip). Naming and reading tasks are required to identify these areas. Whether removal of these areas necessarily induces long-term impairment in verbal abilities is unknown; however, in patients with a low verbal IQ and early seizure onset, these areas appear to be less critical for language processing.

Adolescent↗
PubMed1998

Maximising response rates in a survey of general practitioners. Lessons from a Victorian survey on sexually transmissible diseases.

OBJECTIVE: To describe factors that influence participation by general practitioners (GPs) in survey research, and in particular to examine the effectiveness of telephone prompts made by a GP researcher compared with non-medical researchers in a survey of GPs on sexually transmissible diseases (STDs). DESIGN AND SETTING: A questionnaire survey of knowledge, attitudes, behaviour and practice (KABP) in relation to STDs was distributed to 520 Victorian GPs randomly selected from the Australian Medical Publishing Company's (AMPCo) database of Australian medical practitioners. MAIN OUTCOME MEASURES: Number of GPs able to be contacted by telephone and cumulative and overall response rates to the questionnaire. RESULTS: The overall response rate was 85%. Although the GP researcher was able to make contact by telephone in a higher proportion of cases (80%) than the non-GP researchers combined (69%, p < 0.01) response rates were not significantly different (83% versus 87%). CONCLUSIONS: Telephone prompts to encourage GP response in survey research need not be made by a medical practitioner. Other important factors in relation to response rate that should be considered by researchers are GP involvement in the developing and piloting of the survey instrument, incentives and provision of detailed feedback of the results of the survey.

Adult↗
PubMed1998

The relationship between gait parameters and pain in persons with transtibial amputation: a preliminary report.

This is a preliminary study of the potential relationship between pain and gait parameters in 11 persons with transtibial amputation who underwent gait analysis under both baseline and discomfort walking conditions. Gait analysis included measurement with a VA-Rancho Stride Analyzer of the following gait parameters: velocity, cadence, stride length, gait cycle, and support time. These data were correlated with pain intensity data determined with a standard Visual Analog Scale. Wide ranges of discomfort were reported and corresponding alterations in gait parameters varied greatly in both magnitude and quality. There was no obvious pattern in acclimation to discomfort. A significant correlation was found between pain intensity and the magnitude of change in velocity (p < 0.05). In addition, all subjects reporting significant pain (> 33% of maximum) slowed down, while gait alterations of others varied widely in response to the experience of pain. Further studies with a larger and more homogeneous subject pool to examine these relationships fully are recommended to follow this preliminary report.

Aged↗
PubMed1996

Research in pediatric residency programs.

BACKGROUND AND OBJECTIVES: We have required residents in pediatrics at the Cleveland Clinic Foundation to give research presentations since 1989; this article reviews our experience with this program. Additionally, we sought to determine how many other accredited pediatric programs in the United States also require this. METHODS: Retrospective review of the Cleveland Clinic program; descriptive statistics of other United States residency programs, obtained by questionnaire. RESULTS: Pediatric residents at the Cleveland Clinic have given 108 research presentations since 1989, and have developed 33 (30.5%) of them into manuscripts or abstracts. We mailed questionnaires to 215 pediatric residency program directors and received responses from 177 (82%). Of these, 48 (27%) indicated their programs had a research requirement; residents could present their findings in departmental meetings or submit an abstract or manuscript to a professional society or journal. Respondents cited several barriers to research: residents are too busy, there are too few faculty members to mentor them, financial resources are limited, and there is no residency review committee requirement. CONCLUSIONS: Even though only approximately one fourth of the pediatric residency programs in the United States require research, we feel it is worthwhile experience. Despite barriers, residents can and do perform research and publish their findings.

Curriculum↗
PubMed1995

Ictus emeticus: further evidence of nondominant temporal involvement.

We report two cases of ictal vomiting in patients who had left temporal lobe epilepsy. In one patient, vomiting developed when the discharge spread to the right temporal lobe as seen during depth electrode recording. In the second patient, ictal vomiting occurred with a restricted left temporal discharge, but the patient was left-handed and had right-hemisphere language dominance. These cases provide additional evidence of the involvement of the nondominant temporal lobe in ictus emeticus.

Adolescent↗
PubMed1995

Gait initiation of persons with below-knee amputation: the characterization and comparison of force profiles.

The purpose of this study was to characterize gait initiation of persons with leg amputation and determine whether prosthetic alignment was a critical parameter in the initiation process. Gait initiation was chosen for study because of the difficult neuromuscular demands placed on the body in negotiating the transition from stance to ambulation. In this investigation, ground reaction force data were collected on seven persons with below-knee amputation. These subjects underwent a series of gait initiation trials while varying prosthetic alignment. An analysis of the data demonstrated key elements in the gait initiation process, including the motion of the center of gravity in preparation for steady-state walking. Significant asymmetries in the force profiles of the residual and nonamputated limbs were also found; gait initiation forces were consistently higher for the prosthetic limb and the timings of maxima and minima were indicative of an intact limb preference. Relatively small changes in prosthesis alignment proved not to have statistically significant effects on generalized force parameters. This result is consistent with the findings of other studies that gait initiation is a motor program with certain invariant characteristics.

Aged↗