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L Stewart

Publications and source records attributed to L Stewart.

At least 19 recordsLinked to original sources
PubMed2001

Neuropsychology: music of the hemispheres.

Music may be the food of love but it is also good fodder for cognitive scientists. Here we highlight a recent study of a neuropsychological patient who has lost her ability to read music, but not text, in the absence of any other musical deficit.

Cognition↗
PubMed2001

TMS produces two dissociable types of speech disruption.

We aimed to use repetitive transcranial magnetic stimulation (rTMS) to disrupt speech with the specific objective of dissociating speech disruption according to whether or not it was associated with activation of the mentalis muscle. Repetitive transcranial magnetic stimulation (rTMS) was applied over two sites of the right and left hemisphere while subjects counted aloud and recited the days of the week, months of the year, and nursery rhymes. Analysis of EMG data and videotaped recordings showed that rTMS applied over a posterior site, lateral to the motor hand area of both the right and the left hemisphere resulted in speech disruption that was accompanied by activation of the mentalis muscle, while rTMS applied over an anterior site on the left but not the right hemisphere resulted in speech disruption that was dissociated from activation of the mentalis muscle. The findings provide a basis for the use of subthreshold stimulation over the extrarolandic speech disruption site in order to probe the functional properties of this area and to test psychological theories of linguistic function.

Adult↗
PubMed2001

The role of transcranial magnetic stimulation (TMS) in studies of vision, attention and cognition.

Transcranial magnetic stimulation (TMS) can be conceptualized as a virtual lesion technique, capable of disrupting organized cortical activity, transiently and reversibly. The technique combines good spatial and temporal resolution and, moreover, because it represents an interference technique, can be said to have excellent functional resolution. The following is a review and discussion of the contribution which TMS has made to the study of vision, attention, development and plasticity and speech and language.

Attention↗
PubMed2001

Left posterior BA37 is involved in object recognition: a TMS study.

Functional imaging studies have proposed a role for left BA37 in phonological retrieval, semantic processing, face processing and object recognition. The present study targeted the posterior aspect of BA37 to see whether a deficit, specific to one of the above types of processing could be induced. Four conditions were investigated: word and nonword reading, colour naming and picture naming. Repetitive transcranial magnetic stimulation (rTMS) was delivered over posterior BA37 of the left and right hemispheres (lBA37 and rBA37, respectively) and over the vertex. Subjects were significantly slower to name pictures when TMS was given over lBA37 compared to vertex or rBA37. rTMS over lBA37 had no significant effect on word reading, nonword reading or colour naming. The picture naming deficit is suggested to result from a disruption to object recognition processes. This study corroborates the finding from a recent imaging study, that the most posterior part of left hemispheric BA37 has a necessary role in object recognition.

Adult↗
PubMed2001

Barriers and gateways: a study of nursing students' utilisation of learning support resources.

Many first year nursing students require additional academic support from both their lecturers and learning resources. Anecdotal evidence at an Australian university suggested that 'at risk' students did not follow up lecturer referral. This study identified what learning resources were accessed and what factors influenced students' decisions to follow up or not to follow up lecturer referral. First-year nursing students (n =150) were surveyed towards the end of their second semester regarding their use of learning support services. Twelve students were randomly selected and interviewed regarding their use of learning support and their first year learning experience. Demographic data were analyzed using descriptive statistics. Qualitative data were subjected to content analysis. Results revealed learning support utilisation was related to age and publicity but unrelated to gender or culture. Older students entering through non-traditional entry modes displayed a tendency to self refer to learning support. Younger students (<25 years) often lacked effective learning strategies and were reluctant to access on-campus learning support. For all students positive on and off campus support led to positive outcomes. Faculty and learning support lecturers need to foster integration of learning support for all students and encourage peer-learning partnerships within the foundation subjects.

Adult↗
PubMed2001

Randomized controlled trial comparing couple satisfaction with appointment and telephone follow-up consultation after unsuccessful IVF/ICSI treatment.

Couples undergoing in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) at Aberdeen Maternity Hospital come from a wide geographical area. Increasingly, telephone discussions after unsuccessful treatment have replaced appointments for those who do not live locally. The aim of this study was to compare patient satisfaction with telephone follow-up discussions versus clinic appointments. Couples were separated into those undergoing their first treatment cycle (100 couples) and those undergoing their second or subsequent treatment cycle (85 couples), and then randomized to either a telephone or appointment follow-up. Satisfaction was assessed by a postal questionnaire and analysis conducted on an 'intention to treat' basis. An overall response rate of 91% was achieved. Analysis indicated no statistically significant difference between telephone and appointment groups with regard to the degree of satisfaction. However, there was an association between the type of follow-up and the duration of discussion (P < 0.001): telephone follow-up discussions were significantly shorter than appointment follow-ups. There is the potential for significant savings in costs, both to the service and to patients, by providing telephone follow-up consultations. The savings may be achieved without compromising patient satisfaction as long as clinic appointments remain available as an option for those couples who prefer them.

Appointments and Schedules↗
PubMed2001

High prevalence of celiac disease in patients with type 1 diabetes detected by antibodies to endomysium and tissue transglutaminase.

OBJECTIVE: To establish the prevalence of celiac disease (CD) in children with type 1 diabetes in British Columbia. PATIENTS AND METHODS: Two hundred thirty-three children with type 1 diabetes were prospectively screened for CD using blind testing with the current 'gold standard', immunoglobulin A endomysium antibody (EmA), and the novel immunoglobulin A tissue transglutaminase (tTG) antibody. Those children with positive results were offered small bowel biopsy; a gluten-free diet was recommended if CD was confirmed. RESULTS: Nineteen children were positive for EmA and had an elevated tTG level. One patient from this group was already known to have CD, and the other 18 patients consented to biopsy. One biopsy was normal, three biopsies demonstrated elevated intraepithelial lymphocyte counts with normal morphology and 14 biopsies had morphological changes consistent with CD. Growth parameters were normal in all patients, and nine of 19 children who were positive for EmA were asymptomatic. Seven patients had mild elevation of tTG levels alone. Two children from this latter group had normal biopsies, and five declined biopsy. CONCLUSIONS: At least 14 new cases of CD were detected in addition to four known cases, yielding an overall biopsy-confirmed prevalence of CD of 7.7% (18 of 233). The present study confirms that CD is as prevalent in the pediatric type 1 diabetic population in British Columbia as it is in Europe. Serological screening of these children is important because many children have no symptoms or signs suggestive of CD. This study suggests that tTG serology may also be useful in monitoring response and compliance with a gluten-free diet.

Adolescent↗
PubMed2001

Does the family APGAR effectively measure family functioning?

BACKGROUND: The Family APGAR has been widely used to study the relationship of family function and health problems in family practice offices. METHODS: Data were collected from 401 pediatricians and family physicians from the Pediatric Research in Office Settings network and the Ambulatory Sentinel Practice Network. The physicians enrolled 22,059 consecutive office visits by children aged 4 to 15 years. Parents completed a survey that included the Family APGAR and the Pediatric Symptom Checklist. Clinicians completed a survey that described child psychosocial problems, treatments initiated or continued, and specialty care referrals. RESULTS: Family dysfunction on the index visit often differed from dysfunction at follow-up (kappa=0.24). Only 31% of the families with positive Family APGAR scores at baseline were positive at follow-up, and only 43% of those with positive scores at follow-up had a positive score at the initial visit. There were many disagreements between the Family APGAR and the clinician. The Family APGAR was negative for 73% of clinician-identified dysfunctional families, and clinicians did not identify dysfunction for 83% of Family APGAR-identified dysfunctions (kappa=0.06). CONCLUSIONS: Our data do not support the use of the Family APGAR as a measure of family dysfunction in the primary care setting. Future research should clarify what it does measure.

Adolescent↗
PubMed2001

Melanoma differentiation associated gene-7 (mda-7): a novel anti-tumor gene for cancer gene therapy.

BACKGROUND: The mda-7 gene (melanoma differentiation associated gene-7) is a novel tumor suppressor gene. The anti-proliferative activity of MDA-7 has been previously reported. In this report, we analyze the anti-tumor efficacy of Ad-mda7 in a broad spectrum of cancer lines. MATERIALS AND METHODS: Ad-mda7-transduced cancer or normal cell lines were assayed for cell proliferation (tritiated thymidine incorporation assay, Alamar blue assay, and trypan-blue exclusion assay), apoptosis (TUNEL, and Annexin V staining visualized by fluorescent microscopy or FACs analysis), and cell cycle regulation (Propidium Iodide staining and FACs analysis). RESULTS: Ad-mda7 treatment of tumor cells resulted in growth inhibition and apoptosis in a temporal and dose-dependent manner. The anti-tumor effects were independent of the genomic status of p53, RB, p16, ras, bax, and caspase 3 in these cells. In addition, normal cell lines did not show inhibition of proliferation or apoptotic response to Ad-mda7. Moreover, Ad-mda7-transduced cancer cells secreted a soluble form of MDA-7 protein. Thus, Ad-mda7 may represent a novel gene-therapeutic agent for the treatment of a variety of cancers. CONCLUSIONS: The potent and selective killing activity of Ad-mda7 in cancer cells but not in normal cells makes this vector a potential candidate for cancer gene therapy.

Adenoviridae↗
PubMed2000

Expression of human topoisomerase I with a partial deletion of the linker region yields monomeric and dimeric enzymes that respond differently to camptothecin.

Human topoisomerase I is a 765-residue protein composed of four major domains as follows: the unconserved and highly charged NH(2)-terminal domain, a conserved core domain, the positively charged linker region, and the highly conserved COOH-terminal domain containing the active site tyrosine. Previous studies of the domain structure revealed that near full topoisomerase I activity can be reconstituted in vitro by fragment complementation between recombinant polypeptides approximating the core and COOH-terminal domains. Here we demonstrate that deletion of linker residues Asp(660) to Lys(688) yields an active enzyme (topo70DeltaL) that purifies as both a monomer and a dimer. The dimer is shown to result from domain swapping involving the COOH-terminal and core domains of the two subunits. The monomeric form is insensitive to the anti-tumor agent camptothecin and distributive during in vitro plasmid relaxation assays, whereas the dimeric form is camptothecin-sensitive and processive. However, the addition of camptothecin to enzyme/DNA mixtures causes enhancement of SDS-induced breakage by both monomeric and dimeric forms of the mutant enzyme. The similarity of the dimeric form to the wild type enzyme suggests that some structural feature of the dimer is providing a surrogate linker. Yeast cells expressing topo70DeltaL were found to be insensitive to camptothecin.

Baculoviridae↗
PubMed2000

Fat absorption in cystic fibrosis after correction of hypokalaemia.

Extracellular potassium up-regulates exocrine pancreatic function in tissue preparations of mammalian pancreatic lobules. We report on a child with cystic fibrosis in whom clinical evidence suggested that this laboratory observation may be of relevance to clinical practice.

Administration, Oral↗
PubMed2000

Postcholecystectomy abdominal bile collections.

HYPOTHESIS: The clinical syndromes caused by bile collections in the abdomen span a wide spectrum and their natural history and risks are not fully appreciated. DESIGN: Analysis of 179 patients with bile fistulas after cholecystectomy, of which 154 patients had undrained bile collections. OBJECTIVE: To characterize the manifestations and natural history of abdominal bile collections. SETTING: A tertiary care teaching hospital. PATIENTS AND METHODS: The clinical findings in 179 patients with bile fistulas resulting from iatrogenic laparoscopic bile duct injuries and other miscellaneous operations between 1990 and 1999 were analyzed. The group of main interest consisted of 154 patients with undrained bile collections. Of these 154 patients, 21% had serious complications, including sepsis and multiorgan failure. The data were analyzed to identify the variables associated with this undesirable outcome. MAIN OUTCOME MEASURES: Symptoms, physical findings, course of illness, and laboratory and imaging findings. RESULTS: The clinical manifestations of intra-abdominal bile collections were initially discounted in 77% of patients, so the problem went unsuspected for a variable and often lengthy period. Abdominal pain and tenderness (bile peritonitis) gradually developed in 18% of patients with bile ascites. There were no differences in the initial clinical findings in this group compared with those who did not develop peritonitis. Nineteen percent of patients with undrained bile collections experienced serious morbidity. The initial clinical findings did not differ in these patients compared with those with a less complicated illness. Serious illness, however, was associated with the following: (1) a longer period of undrained bile (15.4 vs 9.2 days, P=.04) and (2) a higher incidence of infected bile (45% vs 7%, P=.001). CONCLUSIONS: (1) Prominent abdominal pain and tenderness developed in only 21% of patients with abdominal bile collections; (2) the symptoms caused by bile collections were often subtle and their significance was overlooked, which resulted in a delay in diagnosis; (3) the early clinical findings could not distinguish patients who did become critically ill from those who did not; and (4) seriously ill patients more often had delayed drainage and infected bile. Still, failure to drain a bile collection within just 5 days resulted in serious illness in a few patients. Surgeons must watch for the clinical manifestations of bile ascites after laparoscopic cholecystectomy. This diagnosis should be suspected whenever persistent bloating and anorexia last for more than a few days; failure to recover as smoothly as expected is the most common early symptom of bile ascites. If bile collections were promptly diagnosed and drained, the rate of serious illness resulting from this complication would decline.

Adolescent↗