Search PubMed⌕ Search

Biomedical subjects

W Morgan

Publications and source records attributed to W Morgan.

At least 19 recordsLinked to original sources
PubMed2001

Effect of choice of reference equation on analysis of pulmonary function in cystic fibrosis patients.

Pulmonary function is an important measure of disease severity and prognosis in cystic fibrosis (CF). It is generally expressed as a percentage of a predicted value, calculated using regression equations derived from a reference population. A number of reference equations are in widespread use. The purposes of this study were to determine: 1) the extent to which, for a given absolute FEV(1) value, percent of predicted (PPFEV(1)) values vary when derived by different reference equations; and 2) whether these differences affect conclusions of longitudinal and cross-sectional analyses. Subjects were all Caucasians 6-18 years old in the 1990 Cystic Fibrosis Foundation Registry. We found clinically important discrepancies in PPFEV(1) when calculated by the methods of Dockery et al. [Am Rev Respir Dis 1983;128:405-412] and Wang et al. [Pediatr Pulmonol 1993;15:75-78] as compared to Knudson et al. [Am Rev Respir Dis 1983;127:725-734] or Polgar and Promadhat [Pulmonary Function Testing in Children 1971; Philadelphia: W.B. Saunders]. In longitudinal analyses, the choice of reference equation resulted in varying apparent rates of decline in FEV(1). For example, among subjects ages 12-14 years in 1990, the decline in PPFEV(1) from 1990-1995 varied between 2-11%, depending on the choice of reference equation. In cross-sectional analyses, the choice of reference equation affected the distribution of subjects classified as having mild, moderate, or severe lung disease. CF physicians should be aware of the impact of choice of reference equation in both clinical care and research.

Adolescent↗
PubMed2000

Comparison of optic disc image assessment methods when examining serial photographs for glaucomatous progression.

AIM: To assess serial, simultaneous stereo optic disc images by four methods for glaucomatous progression. METHODS: Using varying techniques, two ophthalmologists assessed serial optic disc images of 52 eyes from 27 patients with a mean duration between images of 18 months. The neuroretinal rim width was qualitatively assessed by four assessment methods and compared with quantitative rim measurements made using PC based software. RESULTS: The highest sensitivity of 83% was achieved using computerised stereo chronoscopy. CONCLUSION: Stereo chronoscopy improved the detection of subtle optic disc changes when compared with simpler assessment techniques.

Disease Progression↗
PubMed2000

International transmission of tele-ophthalmology images.

Tele-ophthalmic consultations were conducted between a hospital in East Java, Indonesia, and an ophthalmology centre in Perth, Western Australia. Twenty-two eyes of 14 subjects were screened for glaucoma using a hand-held fundus camera. Optic disc images comprised 267 x 234 pixels at 24 bit/pixel (187 kByte). The images were compressed and stored together with patient information on a laptop computer. The images were then transmitted to Perth using either a mobile phone or a satellite phone, taking 170 s or 240 s, respectively. Images were also compressed to five different compression levels before transmission. At a compression ratio of 1:5, the images were 36 kByte in size and took 29 s to transmit by mobile phone and 60 s by satellite phone. To measure the loss of quality, the root mean square error was calculated for each colour component, comparing the transmitted and original images. The coefficients of variation were 10% (green), 15% (blue) and 22% (red). The images received in Perth were considered to be of excellent quality and readily interpreted by ophthalmologists in terms of the likely presence of glaucoma.

Glaucoma↗
PubMed1999

Optic disc topographic changes post-trabeculectomy visualized by anaglyphs.

BACKGROUND: Publications on changes of optic disc topography usually illustrate their findings with two-dimensional images. METHODS: With the introduction of computerized imaging, anaglyphs of stereo images can be produced for illustrations. Anaglyphs are viewed three-dimensionally with red-green spectacles that are included in refraction sets and are normally used to assess phoria. An anaglyph of progressive, glaucomatous progression is included to demonstrate the method, along with conventional colour images. RESULTS: We present two cases of severely altered optic disc topography post-trabeculectomy and illustrate these cases with anaglyphs that can be viewed three-dimensionally. CONCLUSION: Three-dimensional viewing of illustrations assists with the visualization, perception and interpretation of optic disc changes.

Aged↗
PubMed1999

Postoperative deposits on the Acrysof intraocular lens.

PURPOSE: To report a commonly occurring change on the anterior surface of the Acrysof intraocular lens which is presumed to be due to the proliferation of lens epithelial cells from the capsulo-rhexis margin. METHOD: Forty-one consecutive cases (31 patients) of Acrysof intraocular lens implantation were followed prospectively. Clinical charts were reviewed for changes on or within the lens and visual acuity and refractive changes recorded. All cases were dilated at 3-5 weeks postoperatively to facilitate observation of changes. Representative slit lamp photos were taken. RESULTS: Deposits on the intraocular lens surface were noted on 18 of 41 lenses at 3-5 weeks post surgery. Deposits were not found on examinations conducted during the first postoperative week. All changes had fully resolved by 3 months. CONCLUSIONS: The changes recorded had no impact on visual acuity. The deposits noted do not represent clinically important pathology. They may be an unusual marker of biocompatibility with this lens. Surgeons using this lens should be aware of these changes.

Biofilms↗
PubMed1999

Work-related upper-extremity disorders: prospective evaluation of clinical and functional outcomes.

The purpose of this study was to describe the demographic, vocational, medical, workplace, and psychosocial characteristics of patients treated for work-related upper-extremity disorders, to document treatment patterns in a community-practice setting, and to determine which of these factors predicts subsequent employment and functional status outcomes. A questionnaire was administered by mail or telephone to 112 patients seen at the University of Massachusetts Occupational Upper Extremities Disorders Clinic and included measures of disease-specific functional status, pain, reactions to pain, employer-employee relations, and number and type of interventions used to treat the disorder. Results were compared with baseline data obtained, on average, 16 months prior to follow-up. Of the original cohort (n = 124), 112 participated in the prospective study. Although most patients reported improvement in pain severity, fear of pain, life situation, and functional status, there was little change in employment status. Patients' self-reported intentions of return to work at baseline did not predict work status at follow-up. In general, those who were employed at baseline remained employed, had a greater reduction in symptom severity over time, and were significantly more likely to report improvement in their problem than those who were unemployed. The efficacy of various interventions was examined by type, mix, and intensity (number of different interventions undergone by the patient). No positive relationship was found between these measures and employment status, self-reported change in the problem, or self-reported improvement in functional status. Significant negative relationships were found between surgery, psychotherapeutic interventions, and outcomes. This was likely to have occurred because of a selection bias toward the more chronic and severely disabled patients for these treatments. However, the relative ineffectiveness of such intensive interventions as surgery in improving the work and health status of chronically symptomatic work-related upper-extremity patients cannot be overlooked. The findings suggest that more emphasis be placed on interventions aimed at resolving differences between employers and injured employees. More careful selection of patients for expensive and invasive procedures is recommended.

Adult↗
PubMed1999

Evaluation of a portable fundus camera for use in the teleophthalmologic diagnosis of glaucoma.

PURPOSE: The digital images of the optic disk from a portable fundus camera were evaluated for suitability in teleophthalmologic screening for glaucoma. METHODS: Fifty-one eyes of 27 consecutive patients from our glaucoma clinic were dilated and photographed with a Zeiss FF retinal camera (Carl Zeiss, Oberkochen, Germany) and a portable Nidek NM-100 (Nidek, Tokyo, Japan) fundus camera. Digital images from the portable fundus camera were digitized, compressed and stored in a Fujix DF-10M (Fuji, Tokyo, Japan) digitizer. Lossy compressed digital images and photographs from the Zeiss camera were presented separately in random order to three ophthalmologists for estimation of vertical cup:disk ratios (VCDR) and to evaluate image quality as good, acceptable, or unacceptable for screening glaucoma. Gold standard VCDRs were measured from monoscopic photographic slides obtained using the Zeiss camera by a fourth ophthalmologist. RESULTS: Measurement of agreement (Kappa values) between estimated VCDR of digital images and photographs by the three ophthalmologists were 0.52, 0.38, and 0.50 respectively. Agreement between gold standard and estimated VCDR from photographs were 0.87, 0.45, and 0.84 respectively (specificity between 79% and 97%, sensitivity between 70% and 95%). Kappa values obtained between gold standard and estimated VCDR from digital images were 0.52, 0.49, and 0.49, respectively (specificity between 68% and 79%, sensitivity between 67% and 87%. CONCLUSION: Moderate to good agreement indicates that the digital images from the portable fundus camera may be suitable for optic disk assessment in the current configuration. This easy to use Nidek hand-held camera could be a viable instrument for teleophthalmology if a better digitizing system is incorporated to improve the quality of the images.

Diagnostic Techniques, Ophthalmological↗
PubMed1998

The joining of blunt DNA ends to 3'-protruding single strands in Escherichia coli.

In eukaryotic and prokaryotic organisms DNA double-strand breaks with non-complementary ends can be joined by mechanisms of illegitimate recombination. We examined the joining of 3'-protruding single strand (PSS) ends, which do not have recessed 3' hydroxyls that can allow for fill-in DNA synthesis, to blunt ends. End-joining was examined by electro-transforming Escherichia coli strains with linearized plasmid DNA, sequencing the resulting junctions, and determining the transformation frequencies. Three different E.coli strains were examined: MC1061, which has no known recombination or DNA repair defects, HB101 (rec A-) and SURE (recB- recJ-). No striking differences were found in either the spectrum of products observed or the efficiency of end-joining between these strains. As in vertebrate systems, the majority of the products were overlaps between directly repeated DNA sequences. 3'-PSS are frequently preserved in vertebrate systems, but they were not preserved in our experiments unless the transforming DNA was pretreated with a DNA polymerase.

Base Sequence↗
PubMed1995

Congenital hemangiopericytoma of the clitoris.

Hemangiopericytoma is a rare vascular tumor that is believed to arise from the pericyte of Zimmermann. Approximately 10% of cases occur in children and a third are congenital. To our knowledge we report the first case of a congenital hemangiopericytoma arising from the clitoris, describe its management and review the literature.

Clitoris↗
PubMed1995

Work-related upper-extremity disorders and work disability: clinical and psychosocial presentation.

Work-related upper-extremity disorders (WRUEDs) are an increasingly common cause of work-related symptoms and disability. Although most upper-extremity disorders are acute and self-limited, a small percentage of workers with symptoms go on to permanent disability and account for the majority of costs associated with these conditions. Little is known, however, about this progression from symptoms to disability and how it might be prevented. In this study, we evaluate the demographic, vocational, medical, and psychosocial characteristics of patients with WRUEDs and examine several hypotheses regarding the differences between working and work-disabled patients. One hundred twenty-four consecutive patients were evaluated in a clinic specializing in occupational upper-extremity disorders. Patients currently working (n = 55) and work-disabled patients (n = 59) were similar with regard to age, gender, and reported job demands. The work-disabled group reported less time on the job, more surgeries, a higher frequency of acute antecedent trauma, and more commonly had "indeterminate" musculoskeletal diagnoses. They also reported higher pain levels, more anger with their employer, and a greater psychological response or reactivity to pain. These findings, though cross-sectional in nature, suggest that, in addition to medical management, more aggressive approaches to pain control, prevention of unnecessary surgery, directed efforts to improve patients' abilities to manage residual pain and distress, and attention to employer-employee conflicts may be important in preventing the development of prolonged work disability in this population.

Adult↗
PubMed1994

Development of a multidisciplinary research clinic for patients with work-related upper extremity disorders.

The health care reform debate has focused attention on the need for outcomes research performed in ambulatory care settings. In this article, the authors describe the development of a research clinic focusing on symptomatic, functional, and vocational outcomes of patients with work-related upper extremity disorders. The authors describe the programmatic and research challenges associated with performing such research and emphasize the need for balancing the research and clinical agendas. Research efforts in this setting require careful consideration of the patient selection process and allocation of sufficient time for the clinical staff to collect and record essential research data.

Academic Medical Centers↗
PubMed1994

Renal function and hyperfiltration capacity in lead smelter workers with high bone lead.

OBJECTIVE: The study was undertaken to assess whether the changes in urinary excretion of eicosanoids (a decrease of 6-keto-PGF1 alpha and PGF2 and an increase of thromboxane) previously found in lead (Pb) exposed workers may decrease the renal haemodynamic response to an acute oral protein load. METHODS: The renal haemodynamic response was estimated by determining the capacity of the kidney to increase the glomerular filtration rate (in terms of creatinine clearance) after an acute consumption of cooked red meat (400 g). A cross sectional study was carried out in 76 male Pb workers (age range 30 to 60 years) and 68 controls matched for age, sex, socioeconomic state, general environment (residence), and workshift characteristics. RESULTS: The Pb workers had been exposed to lead on average for 18 (range 6-36) years and showed a threefold higher body burden of Pb than the controls as estimated by in vivo measurements of tibial Pb concentration (Pb-T) (geometric mean 66 v 21 micrograms Pb/g bone mineral). The geometric mean concentrations of Pb in blood (Pb-B) and Pb in urine (Pb-U) were also significantly higher in the Pb group (Pb-B: 430 v 141 micrograms Pb/l; Pb-U: 40 v 7.5 micrograms Pb/g creatinine). These conditions of chronic exposure to Pb did not entail any significant changes in the concentration of blood borne and urinary markers of nephrotoxicity, such as urinary low and high molecular weight plasma derived proteins (beta 2-microglobulin, retinol binding protein, albumin, transferrin), urinary activities of N-acetyl-beta-D-glucosaminidase and kallikrein, and serum concentrations of creatinine, beta 2-microglobulin, urea, and uric acid. All participants also had normal baseline creatinine clearances (> 80 ml/min/1.73 m2) amounting on average to 115.5 in the controls v 121.3 ml/min/1.73 m2 in the Pb group. Both control and Pb exposed workers showed a significant increment in creatinine clearance (on average 15%) after oral protein load suggesting that the previously found changes in secretion of urinary eicosanoids apparently has no deleterious effect on renal haemodynamics in the examined Pb workers. CONCLUSIONS: The finding that both baseline and stimulated creatinine clearance rates were not only significantly higher in the Pb workers but also positively correlated with Pb-T, suggests that moderate exposure to Pb may be associated with a slight hyperfiltration state, which has been found to attenuate the age related decline in baseline creatinine clearance by a factor of two. Although the relevance of this effect for the worker's health is unknown, it can be concluded that adverse renal changes are unlikely to occur in most adult male Pb workers when their blood Pb concentration is regularly kept below 700 micrograms Pb/l. One should, however, be cautious in extra-polating this conclusion to the general population because of pre-employment screening of the Pb workers for the absence of renal risk factors.

Adult↗
PubMed1994

Epidemiology of physician-diagnosed allergic rhinitis in childhood.

OBJECTIVE: To investigate the natural history of and risk factors for allergic rhinitis in the first 6 years of life. METHODS: Parents of 747 healthy children followed from birth completed a questionnaire when the child was 6 years old. Data were obtained regarding physician-diagnosed allergic rhinitis (PDAR), associated symptoms, and age at onset. Risk-factor data were taken from earlier questionnaires, and data regarding immunoglobulin E (IgE) and skin-test reactivity were obtained at age 6. RESULTS: By the age of 6, 42% of children had PDAR. Children whose rhinitis began in the first year of life had more respiratory symptoms at age 6 and were more likely to have a diagnosis of asthma. Early introduction of foods or formula, heavy maternal cigarette smoking in the first year of life, and higher IgE, as well as parental allergic disorders, were associated with early development of rhinitis. Risk factors for PDAR that remained significant in a multivariate model included maternal history of physician-diagnosed allergy (odds ratio: 2.2, 95% confidence interval: 1.35-3.54), asthma in the child (4.06, 2.06-7.99), and IgE greater than 100 IU/mL at age 6 (1.93, 1.18-3.17). The odds for atopic as opposed to nonatopic PDAR were significantly higher only among those with high IgE and those who had dogs. CONCLUSION: Allergic rhinitis developing in the first years of life is an early manifestation of an atopic predisposition, which may be triggered by early environmental mental exposures.

Age of Onset↗
PubMed1993

Gender related differences in airway tone in children.

The effects of gender, volume history, and inhaled atropine and isoproterenol on lung mechanics were assessed in 16 normal boys and 14 normal girls using lung volumes, flow-volume curves, and oscillatory resistances. Flows were measured from full and partial forced expiratory flow-volume curves. Six girls and 6 boys were studied before and after inhaled atropine, and 10 boys and 8 girls before and after inhaled isoproterenol. Girls demonstrated a significant increase in flows on full and partial curves with a deep inspiration [Vmax-partial 0.73 +/- 0.34 (SD) to Vmax-full 0.80 +/- 0.37 and 0.83 +/- 0.20 to 1.06 +/- 0.29 TLC/s in each group] and following inhalation of isoproterenol on the partial curves only (0.73 +/- 0.34 to 0.93 +/- 0.40 TLC/s). Boys showed a small but significant increase in Vmax with isoproterenol on full curves but not on partial curves. Following atropine, boys demonstrated a significant increase in Vmax on partial flow-volume curves (0.78 +/- 0.28 to 1.00 +/- 0.35 TLC/s) and a significant decrease in specific respiratory resistance (7.6 +/- 2.7 to 5.1 +/- 0.9 cmH2O/s), whereas girls had no such changes. These data suggest that boys have greater resting airway tone than girls and that this tone is less responsive to deep inspiration and isoproterenol independently, although a combination of isoproterenol and a deep inspiration will produce increased flows in boys. Atropine reduces airway tone predominantly in boys, suggesting that the increased resting airway tone in boys is partially mediated via the vagus nerve.

Airway Resistance↗
PubMed1993

Isolated amyloidosis of the penile urethra and corpus spongiosum: a case report.

Localized amyloidosis of the penile urethra and corpus spongiosum is rare. The pathogenesis is obscure and optimal management of such patients has not been defined. We report a case that was treated with transurethral removal of amyloid tissue, which was obstructing the urethral outlet. Previously, the patient had been treated with dilation with temporary relief of the symptoms. He was disease-free 1 1/2 years postoperatively.

Adult↗
PubMed1993

Activity of microbial peptidases, oxidases, and esterases in lake waters of varying trophic status.

The range and activities of microbial enzymes present in lake water were assessed directly in cells concentrated by tangential flow filtration. A total of 108 enzymes were assayed in this study, which included tests for 60 peptidases, 20 oxidases, and 10 esterases, and 18 miscellaneous tests. In general, no trends in the range of enzymes were associated with trophic status of the lakes. However, one lake that was hypereutrophic had a greater range of enzymes than the other lakes tested. An increase in total enzyme activity (activity/mL) was recorded with an increase in trophic status of the water. The relationship between the physical and chemical attributes of each lake and microbial enzyme activities was investigated by principal component analysis. Quantitative changes between lakes in 11 of the 21 variables were shown to be closely related to changes in the enzyme activities of the lakes; total organic carbon, particulate carbon, particulate nitrogen, pH, and chlorophyll a showed the closest relationships.

Bacterial Proteins↗
PubMed1993

Africa: using radio soap operas to promote family planning.

Programmes that combine mass media and popular entertainment formats can be a potent force in health communication since they can reach large audiences with persuasive messages. Not only can such programmes increase knowledge and stimulate approval, but also, when used effectively, they can change behaviour.

Adult↗