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Biomedical subjects

D W Lewis

Publications and source records attributed to D W Lewis.

At least 19 recordsLinked to original sources
PubMed2005

Atomoxetine treatment in children and adolescents with ADHD and comorbid tic disorders.

OBJECTIVE: To test the hypothesis that atomoxetine does not significantly worsen tic severity relative to placebo in children and adolescents with attention deficit/hyperactivity disorder (ADHD) and comorbid tic disorders. METHODS: Study subjects were 7 to 17 years old, met Diagnostic and Statistical Manual of Mental Disorders-IV criteria for ADHD, and had concurrent Tourette syndrome or chronic motor tic disorder. Patients were randomly assigned to double-blind treatment with placebo (n = 72) or atomoxetine (0.5 to 1.5 mg/kg/day, n = 76) for up to 18 weeks. RESULTS: Atomoxetine treatment was associated with greater reduction of tic severity at endpoint relative to placebo, approaching significance on the Yale Global Tic Severity Scale total score (-5.5 +/- 6.9 vs -3.0 +/- 8.7, p = 0.063) and Tic Symptom Self-Report total score (-4.7 +/- 6.5 vs -2.9 +/- 5.2, p = 0.095) and achieving significance on the Clinical Global Impressions (CGI) tic/neurologic severity scale score (-0.7 +/- 1.2 vs -0.1 +/- 1.0, p = 0.002). Atomoxetine patients also showed greater improvement on the ADHD Rating Scale total score (-10.9 +/- 10.9 vs -4.9 +/- 10.3, p < 0.001) and CGI severity of ADHD/psychiatric symptoms scale score (-0.8 +/- 1.1 vs -0.3 +/- 1.0, p = 0.015). Discontinuation rates were not significantly different between treatment groups. Atomoxetine patients had greater increases in heart rate and decreases of body weight, and rates of treatment-emergent decreased appetite and nausea were higher. No other clinically relevant treatment differences were seen in any other vital sign, adverse event, or electrocardiographic or laboratory measures. CONCLUSIONS: Atomoxetine did not exacerbate tic symptoms. Rather, there was some evidence of reduction in tic severity with a significant reduction of attention deficit/hyperactivity disorder symptoms. Atomoxetine treatment appeared safe and well tolerated.

Adolescent↗
PubMed2003

Observer agreement in the grading of oral epithelial dysplasia.

OBJECTIVES: To determine the extent of observer agreement in diagnosis of oral epithelial dysplasia (OED). Published studies of OED examiner agreement report relatively low agreement levels; however, these studies were limited by the methodologies employed. METHODS: For this study, 64 slides were each independently examined twice by three oral pathologists. Consistency was assessed by determining intra- and interexaminer agreement. Conformity was assessed by using the modal diagnosis as a gold standard. RESULTS: The group showed moderate interobserver agreement when grading the presence or absence of OED with a group-simple kappa (Ks) of 0.51 (95% CI = 0.42-0.61), and substantial agreement when using a 5-point ordinal scale with a group-weighted kappa (Kw) of 0.74 (95% CI = 0.64-0.85). The group showed fair to substantial intraexaminer agreement when assessing the presence or absence of OED, with Ks ranging from 0.22 to 0.78, and showing almost a perfect agreement using a 5-point ordinal scale, with Kw ranging from 0.82-0.96. Conformity with the comparison standard modal diagnosis was almost perfect, with pairwise Kw ranging from 0.81 to 0.92. CONCLUSION: Overall, there was substantial intra- and interobserver consistency and almost perfect conformity in the grading of OED. Appropriate statistical methods are necessary to determine the degree of observer agreement.

Adult↗
PubMed2002

Practice parameter: evaluation of children and adolescents with recurrent headaches: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society.

OBJECTIVE: The Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society develop practice parameters as strategies for patient management based on analysis of evidence. For this parameter, the authors reviewed available evidence on the evaluation of the child with recurrent headaches and made recommendations based on this evidence. METHODS: Relevant literature was reviewed, abstracted, and classified. Recommendations were based on a four-tiered scheme of evidence classification. RESULTS: There is inadequate documentation in the literature to support any recommendation as to the appropriateness of routine laboratory studies or performance of lumbar puncture. EEG is not recommended in the routine evaluation, as it is unlikely to define or determine an etiology or distinguish migraine from other types of headaches. In those children undergoing evaluation for recurrent headache found to have a paroxysmal EEG, the risk for future seizures is negligible; therefore, further investigation for epilepsy or treatments aimed at preventing future seizures is not indicated. Obtaining a neuroimaging study on a routine basis is not indicated in children with recurrent headaches and a normal neurologic examination. Neuroimaging should be considered in children with an abnormal neurologic examination or other physical findings that suggest CNS disease. Variables that predicted the presence of a space-occupying lesion included 1) headache of less than 1-month duration; 2) absence of family history of migraine; 3) abnormal neurologic findings on examination; 4) gait abnormalities; and 5) occurrence of seizures. CONCLUSIONS: Recurrent headaches occur commonly in children and are diagnosed on a clinical basis rather than by any testing. The routine use of any diagnostic studies is not indicated when the clinical history has no associated risk factors and the child's examination is normal.

Adolescent↗
PubMed2001

Solvent-free routes to clean technology.

A major aim for the chemical technology of the future is the avoidance of noxious and environmentally unacceptable organic solvents. In this concept article we discuss more environmentally friendly and highly selective alternatives which we have evolved for carrying out a number of important chemical conversions. These entail the use of porous heterogeneous catalysts in which the active sites have been atomically engineered and fully characterized. Such solid catalysts operate under solvent-free conditions and usually entail one-step processes.

Journal Article↗
PubMed2001

Headache in the pediatric emergency department.

Headache is one of the most common presenting complaints to emergency departments. Although the overwhelming majority of these headaches are benign and self-limited, headache can be the initial symptom of life-threatening disorders. It is therefore essential for physicians to have a rational approach to the evaluation of a child or adolescent who presents to the emergency department with headache. The purpose of this article is to review the causes, evaluation, and appropriate investigations for nontraumatic headache in the pediatric emergency department.

Adolescent↗
PubMed2000

Acute headache in children and adolescents presenting to the emergency department.

OBJECTIVES: Our goals were (1) to investigate the causes of acute headache in childhood from the emergency department perspective and (2) to search for clinical clues that might distinguish headache associated with serious underlying disease. BACKGROUND: The clinical presentation of headache in children and adolescents can be separated into 5 temporal patterns: acute, acute-recurrent, chronic progressive, chronic nonprogressive, and mixed. Few data exist regarding acute headache in children. METHODS: Consecutive children who presented to our emergency department with the abrupt onset of severe headache were prospectively evaluated. The headache character, location, severity, and associated symptoms, as well as underlying causes, were recorded using a standardized survey. RESULTS: One hundred fifty children, aged from 2 to 18 years, 87 boys and 63 girls, were enrolled over a 10-month period. Upper respiratory tract infection with fever (viral upper respiratory tract infection 39%, sinusitis 9%, streptococcal pharyngitis 9%) was the most frequently identified cause of acute headache (57%). Other causes included migraine (18%), viral meningitis (9%), posterior fossa tumors (2.6%), ventriculoperitoneal shunt malfunction (2%), epileptic seizure (postictal headache) (1.3%), concussion (postconcussive headache) (1. 3%), intracranial hemorrhage (1.3%), and undetermined (7%). Two clinical features were found to have statistically significant associations with serious underlying disease: occipital location of headache and an inability of the patient to describe the quality of the head pain. All children with surgically remediable conditions had clear and objective neurological signs. CONCLUSIONS: In children and adolescents, the abrupt onset of severe headache is most frequently caused by upper respiratory tract infection with fever, sinusitis, or migraine. Special attention is warranted if the acute headache is occipital in location and if the affected patient is unable to describe the quality of the pain. Serious underlying processes such as brain tumor or intracranial hemorrhage are uncommon and, when present, are accompanied by multiple neurological signs (ataxia, hemiparesis, papilledema).

Acute Disease↗
PubMed2000

The utility of neuroimaging in the evaluation of children with migraine or chronic daily headache who have normal neurological examinations.

OBJECTIVES: To assess the utility of neuroimaging in the evaluation of children presenting with two of the most common forms of headache, migraine and chronic daily headache, and to determine the utility and pathological yield of neuroimaging in specific headache syndromes in children whose neurological examinations are normal. METHODS: We retrospectively reviewed the medical records of patients coded for headache (ICD 784) in the Pediatric Neurology Clinic at Children's Hospital of the King's Daughters between 1997 and 1999. The age range considered was between 6 and 18 years. The study focused on the two most common types of headache, uncomplicated migraine and chronic daily headache. Only patients with normal physical and neurological examinations were considered in this analysis. RESULTS: Three hundred two patients were coded for headache within the defined age group. One hundred seven (35.4%) patients fulfilled IHS-R criteria as having uncomplicated migraine with a normal examination, and 30 (9.9%) patients fulfilled criteria for chronic daily headache. Twenty-nine (9.6%) patients presented with migrainelike symptoms, and 6 (2.0%) presented with chronic daily symptoms, but had neurological abnormalities present on examination. The remainder of the patients with headache had the following etiologies: 50 (16.6%) with secondary headache, 22 (7.3%) with complicated migraine, 20 (6.6%) with posttraumatic headache, 13 (4.3%) with seizure-related headache, 11 (3.6%) with brain tumors, 10 (3.3%) with tension-type headache, and 4 (1.3%) with pseudotumor cerebri. Of the 107 patients with migraine, 42 (39.3%) received CT scans; 2 (4.8%) of which were considered "abnormal." One of the abnormalities was an arachnoid cyst and the other was a dilated Virchow-Robin space. Twelve (11.2%) patients with migraine received an MRI, 2 (16.7%) of which were considered abnormal. Both of the abnormal findings were Chiari type I malformations. Of the 30 patients with chronic daily headache, 17 (56.7%) received CT scans, 3 (17.6%) of which were considered abnormal. The abnormalities consisted of a maxillary opacification, a mucous retention cyst, and an occult vascular malformation. Eight (26.7%) of the patients with chronic daily headache had an MRI, 2 (25.0%) of which were abnormal. One of the abnormalities was a Chiari I malformation, and the other was an occult vascular malformation. CONCLUSION: The yield of neuroimaging in children with uncomplicated migraine and normal neurological examination was 3.7%. The yield in children with chronic daily headache and normal neurological examination was higher at 16.6%. The abnormalities discovered included arachnoid cysts, Chiari I malformations, sinus disease, occult vascular malformations and "dilated Virchow-Robin spaces." While none of the neuroimaging findings were apparent clinically, their discovery did not influence the diagnosis, management, or outcome of the patients. None of the abnormalities necessitated surgical intervention or were associated with the headache presentation. Therefore, neuroimaging is not warranted in children and adolescents with defined clinical headache syndrome diagnoses whose neurological examinations are normal.

Adolescent↗
PubMed1998

Optimized therapy for the edentulous predicament: cost-effectiveness considerations.

After proof of the clinical effectiveness of prosthodontic interventions, comparative economic analyses (cost-effectiveness, cost benefit, cost utility) should be undertaken to establish the relative value of each intervention in terms of its costs and consequences. Over time, these analyses must consider the balance between each intervention's initial and maintenance costs versus a broad array of clinician and patient-based multidimensional benefits or outcomes. The findings of current research will enhance increased economic analysis in prosthodontics, which, in turn, may help both dentists' and patients' decision-making. Even implant-supported prostheses that are clinically effective have yet to be proven societally effective because they are inaccessible economically to some who need them. Long-term, multidimensional comparative economic analyses of overdenture and conventional denture use may lead to the expansion of implant-supported dentures to selected patients who, to date, have not had access to this treatment modality.

Aged↗
PubMed1998

Dental caries knowledge in a group of Northwest Territories children.

A total of 953 children in schools in communities in the Northwest Territories was surveyed to determine their attitudes and knowledge about dental decay. A questionnaire was answered by these Native and non-Native children in the Northwest Territories. The median age of the children was 12.5 years. The girls tended to brush their teeth more frequently and consumed less sugared sweets between meals. More of the girls and in particular the Native girls knew about "nursing" caries. The Native students more often than not went for dental treatment when it was necessary. The Native students brushed their teeth less frequently and often learned to brush their teeth on their own. The consumption of sugared sweets between meals was greater in the Native sample. The knowledge level of the factors that affect dental decay rates was lower in the Native group, but was not extremely high in either group. These children should receive more information on oral health practices and be given an opportunity to improve their oral health knowledge.

Adolescent↗
PubMed1998

How competent do our graduates feel?

As part of a review of the undergraduate curriculum to assess its relevance for a future general practitioner, a survey of self-perceived competency at graduation based on the competency list developed by the Association of Canadian Faculties of Dentistry was circulated to recent graduates and the graduating class. The overall response was 67.5 percent, and revealed that approximately 70 percent of the respondents felt well prepared in approximately 69 percent of the competencies. These were the common "bread and butter" items of dentistry, such as basic restorative dentistry, examination, diagnosis, treatment planning, local anaesthesia, and scaling. Those areas reported as less well-prepared for included financial and personnel management, performance of soft-tissue biopsies, and management of chronic orofacial pain. Clarification of the raw survey results in focus groups was needed to uncover specific details that could lead to remedial action in problem areas.

Analysis of Variance↗
PubMed1997

L-[1-(13)C] Phenylalanine oxidation as a measure of hepatocyte functional capacity in end-stage liver disease.

BACKGROUND: Liver disease is associated with impaired metabolism of these amino acids phenylalanine and tyrosine. Decreased metabolism of these amino acids leads to abnormal plasma elevations and impaired clearance rates. We have developed a noninvasive breath test that measures hepatic cytosolic enzyme activity. METHODS: The rate of hepatic phenylalanine metabolism was quantitatively calculated from the appearance of 13CO2 in the breath using the nonradioactive tracer L-[1-(13)C]phenylalanine. RESULTS: Normal controls (n = 47) oxidized phenylalanine more than twice that of end-stage liver disease patients (n = 117). Significant differences in the percent of phenylalanine oxidized per hour (mean +/- SEM) were found between controls (7.08% +/- 0.33%, 95% CI: 6.42%-7.74%) and Child Pugh classification patients, class A (4.96% +/- 0.69%, 95% CI: 3.50%-6.42%), class B (2.88% +/- 0.13, 95% CI: 2.39%-3.38%) and class C (1.75% +/- 0.13, 95% CI: 1.50%-2.01%). The phenylalanine breath test score significantly correlated with albumin levels, prothrombin time and total bilirubin. CONCLUSION: We have demonstrated that phenylalanine oxidation is significantly decreased with end-stage liver disease and is correlated with the best clinical measures of liver disease.

Adult↗
PubMed1997

Influence of the addition of restorations on the diagnosis of caries from digitized bitewing radiographs.

OBJECTIVES: The purpose of this study was to assess the influence of additional caries and restorations on the detection of caries on the same radiograph. STUDY DESIGN: Six participants examined five series of four radiographs in which natural carious lesions were present. Each series consisted of the same image with progressively more restorative treatment digitally painted on. The films were randomly presented to the observers who examined the films for the presence and depth of carious lesions. The observers were not informed that the 20 films were disguised versions of the same original five radiographs. RESULTS: The number of carious lesions reported by the six observers did not increase despite the apparent increased restorative intervention viewed on the radiographs. CONCLUSIONS: The complexity of restorative care does not affect observers' ability to correctly detect approximal carious lesions.

Adult↗
PubMed1997

Restorative certainty and varying perceptions of dental caries depth among dentists.

OBJECTIVE: The question of whether dentists who most frequently identify tooth surfaces for definite restoration perceive dental caries as significantly deeper than other dentists is assessed. METHODS: One group of 20 dentists independently examined 145 unrestored approximal tooth surfaces on 16 bitewing radiographs and recorded their restorative and depth decisions. Another group of 15 dentists similarly scored 304 unrestored surfaces on 30 bitewing radiographs. Each group of dentists was later divided into four subgroups according to the number of surfaces designated for definite restoration by each dentist. RESULTS: As the number of tooth surfaces designated for definite restoration increased, mean caries depth (P < .05 for the high vs low subgroups) and the percent of dentinally carious surfaces increased, while the percent of surfaces assessed as sound decreased. Dentists with the lower numbers of surfaces designated for definite restoration came closest to the true histologic mean caries depth of the examined tooth surfaces. CONCLUSIONS: Dentists who designated high numbers of approximal tooth surfaces for definite restoration assessed caries as deeper than other dentists, and deeper than was proven histologically.

Analysis of Variance↗
PubMed1997

A survey of general dentists in Ontario, Part II: Knowledge and use of topical fluoride and dental prophylaxis practices.

A mail questionnaire was used to assess variations in the knowledge and practices of Ontario dentists with respect to topical fluoride and prophylaxis procedures. The questionnaire was answered by 1,276 general dentists. A high percentage (72 to 83 per cent) of respondents identified six months as the optimal time interval at which both procedures should be repeated for all patients under 19 years of age. Relatively few dentists (< 10 per cent) indicated that there should be no specific time interval for re-treatment (i.e. that it should be individually selected). The respondents' preventive knowledge was found to be deficient in two areas: few dentists (16 per cent) knew that it is not necessary to provide a prophylaxis prior to topical fluoride application to achieve maximum caries protection; and most dentists overestimated the speed of caries progress from outer enamel to the dentinoenamel junction (DEJ) in both primary (83 per cent) and permanent (82 per cent) approximal tooth surfaces. In bivariate analysis, three variables were found to be consistently and significantly related to optimal time intervals selected for both topical fluoride application and prophylaxis procedures: year of graduation from dental school; level of hygienist employment; and percentage of patients with private insurance. Multivariate analysis also identified three significant variables: year of graduation from dental school; level of dental hygienist employment; and practice business. Continuing education courses are suggested as a means of updating dentists' knowledge regarding preventive services. Studies are needed to determine the extent to which recent recommendations regarding the professional application of topical fluorides have been followed.

Adolescent↗
PubMed1996

Pediatric headaches: what do the children want?

One hundred consecutive children (aged 3 to 17 years), drawn from primary care pediatric clinics, with a greater than 3-month history of headaches completed surveys to determine the type and associated features of their headache and to query their reasons for wanting to see a physician. Additionally, the children were asked to draw pictures of how they felt when they had a headache to assess their nonverbal perceptions. Over 90% of the headaches were migrainous (65% common, 23% classic, 5% basilar). The children wanted three answers from the physician: what was the cause of their headache, what would make it better, and reassurance that they had no life-threatening illness. Furthermore, 33% of the children's illustrations disclosed depressive features of helplessness, frustration, and anger. Over 20% of the adolescents depicted themselves as dead, dying, or about to be killed by their headache.

Adolescent↗
PubMed1996

Dentists' variability in restorative decisions, microscopic and radiographic caries depth.

Restorative and dental caries depth decisions were recorded for 5168 un restored approximal tooth surfaces by 17 dentists who worked in the school dental clinics of the North York (Ontario) Public Health Department. Each dentist examined 15 pairs of experimental bitewing radiographs for which true caries depth had previously been determined by microscopy of the sectioned teeth following production of the radiographs. The dentists independently recorded their restorative decisions and radiographic caries depth perceptions. The relationship between the variation in the dentists' restorative decisions and their perceptions of caries depth based on a re-reading of the bitewings on the one hand, and true caries depth on the other was also examined. The percentages of total variability in each dentist's restorative decisions attributable to radiographic and to microscopic caries depth were estimated using regression analyses. Large variations were found among the 17 dentists' distributions of overall restorative and depth decisions. The relationship between microscopic caries depth and the dentists' restorative decisions was, understandably, less strong than that of the dentists radiographic perceptions of caries depth and restorative decisions. Relative to true caries depth, high numbers of false positive and false negative restorative decisions were made. Overall, 50% of the variability in the dentists' restorative decisions was explained by the perceptions of radiographic caries depth; however, among individual dentists, the range was from 29% for one dentist to 69% for another. A much lower percentage of the overall restorative variation was explained by microscopic depth, 18%. Like the finding of the only two previous European studies that quantified the role of radiographs on clinical decisions, this study demonstrated that dentists' perceptions of dental caries depth using bitewing radiographs play a major but variable role in their restorative decisions for approximal tooth surfaces.

Clinical Competence↗
PubMed1996

Dentists' stated restorative treatment thresholds and their restorative and caries depth decisions.

OBJECTIVE: This study examines the relationships between stated restorative treatment thresholds of 16 dentists and both their restorative decisions and caries depth determinations for approximal tooth surfaces based on bitewing radiographs. METHODS: Sixteen dentists independently examined 15 pairs of experimental bitewing radiographs. They separately recorded restorative and dental caries depth decisions for 4,864 unrestored approximal tooth surfaces, 304 identical surfaces per dentist. In addition to caries depth and restorative decision data, these dentists provided their restorative thresholds using a five-point scale. RESULTS: Three dentists stated it would be appropriate to restore enamel lesions, nine would wait until caries had reached the dentinoenamel junction, and four would wait until caries extended into the dentine. Although dentists stating an enamel restorative threshold intended definitely or probably to restore relatively more surfaces and recorded relatively more surfaces with dentinal caries, ANOVA analyses revealed that the differences among the restorative and the depth means according to the restorative thresholds were not significant. Considerable variation existed in both the restorative and depth decisions among the dentists in each threshold group. CONCLUSION: Although interesting trends occurred in the restorative and depth decisions relative to the stated thresholds, this study suggests, like others in Europe, that these thresholds cannot be taken at face value to explain restorative decisions.

Analysis of Variance↗