Internet addiction: genuine diagnosis or not?
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Attitude to Computers↗
Biomedical subjects
P Mitchell
Publications and source records attributed to P Mitchell.
Dietary fat and fish intake and age-related maculopathy.
OBJECTIVE: To assess whether dietary intake of fat or fish is associated with age-related maculopathy (ARM) prevalence. DESIGN: Cross-sectional, urban population-based study. PARTICIPANTS: People (N = 3654) aged 49 years or older. MAIN OUTCOME MEASURES: Subjects with ARM were identified from masked grading of retinal photographs. A 145-itemself-administered, semiquantitative food frequency questionnaire was completed adequately by 88.8% of participants and was used to assess intakes of dietary fat and fish. RESULTS: A higher frequency of fish consumption was associated with decreased odds of late ARM (odds ratio for frequency of consumption more than once per week compared with less than once per month, 0.5). Subjects with higher energy-adjusted intakes of cholesterol were significantly more likely to have late ARM, with an increased risk for late ARM for the highest compared with the lowest quintile of intake (odds ratio, 2.7). CONCLUSION: The amount and type of dietary fat intake may be associated with ARM.
Aged↗
Iris color and cataract: the Blue Mountains Eye Study.
PURPOSE: To investigate the relationship between eye color and cataract. METHODS: A population-based cross-sectional study (N = 3654) was conducted near Sydney, Australia. Lens photographs were graded for cortical, nuclear, and posterior subcapsular cataract. Iris color was assessed at slit-lamp examination by comparison with four photographic standards. RESULTS: Eyes with dark brown irises were more likely to have nuclear (adjusted odds ratio, 1.59; 95% confidence interval [CI], 1.03 to 2.28) or posterior subcapsular cataract (adjusted odds ratio, 2.50; 95% CI, 1.57 to 3.98) than eyes with lighter-colored irises. CONCLUSIONS: People with dark brown eyes are at increased risk of cataract and should be encouraged to protect their eyes from direct exposure to sunlight.
Cataract↗
Covered expandable tracheal stents in the management of benign tracheal granulation tissue formation.
BACKGROUND: Tracheal obstruction secondary to benign proliferation of granulation tissue is a difficult problem to address if tracheal resection is contraindicated. Some patients may benefit from Nd:YAG (neodymium: yttritium-aluminum garnet) laser fulguration or tracheal stenting. If uncovered expandable metallic stents are employed granulation tissue can regrow and proliferate through the mesh, thereby obstructing the lumen once again. Covered metallic stents confer the advantage of preventing granulation tissue proliferation and therefore maintain patency of the tracheal lumen. METHODS: Two patients who developed tracheal obstruction secondary to proliferating granulation tissue formation after tracheostomy and who were medically unfit for prolonged general anesthesia were successfully treated using covered expandable metallic tracheal stents. RESULTS: Each patient demonstrated a significant improvement in respiratory status, and in both patients, at 6 and 9 months' follow-up, stent position has not changed, tracheal lumen remains patent, and there has been no proliferation of granulation tissue through the stent. CONCLUSIONS: Covered expandable metallic stents should be considered in the management of patients with proliferating tracheal granulation tissue when tracheal resection is contraindicated.
Adult↗
The prevalence of age-related maculopathy: the visual impairment project.
PURPOSE: To determine the prevalence of age-related maculopathy (ARM) lesions in residents of the state of Victoria, Australia. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Total of 5147 residential and institutionalized persons aged 40 years and older, living in Victoria. METHODS: Participants were recruited through a cluster, stratified, random sampling from nine urban clusters and four rural clusters. The presence of ARM lesions was graded from color stereo fundus photographs as well as slit-lamp stereo biomicroscopy according to the International Classification and Grading System. MAIN OUTCOME MEASURES: The presence of ARM lesions. RESULTS: The mean age of participants was 60.2 years, and 55% were females. Gradable fundus photographs were available for at least one eye in 4345 (92%) of the participants. The weighted prevalence of neovascular age-related macular degeneration (AMD) was 0.39% (95% confidence limits [CL] = 0.20, 0.58), atrophic AMD was 0. 27% (95% CL = 0.04, 0.50), and total AMD was 0.68% (95% CL = 0.30, 1. 1). Prevalence of AMD was strongly related to age (P < 0.001). Prevalence of early ARM was 15.1% (95% CL = 13.7, 16.4). Large drusen, 125 micrometer or more, were present in 6.3% of the participants. There was a higher prevalence of soft distinct drusen (7.5%) than soft indistinct drusen (4.3%). Retinal pigmentary abnormalities were present in 8.2% (95% CL = 7.2, 9.2). The prevalence of large drusen, soft drusen, and pigmentary abnormalities increased with age (P < 0. 001). Prevalence of retinal pigmentary abnormalities increased with increasing drusen size (P < 0.001). Soft indistinct drusen were more common in women aged 70 years or older (P < 0.001). Bilaterality of any ARM was strongly age related, and women appeared to have a higher risk of both bilateral early ARM and AMD. CONCLUSIONS: These data provide age- and gender-specific prevalence of ARM and its component lesions in an ethnically diverse Australian population. Early ARM and AMD prevalence rates increased sharply from ages 70 and 80 years, respectively, in all ethnic groups. These higher rates will continue to increase the importance of AMD as our population ages.
Adult↗
Diet and cataract: the Blue Mountains Eye Study.
PURPOSE: To investigate relationships between a wide range of macro- and micronutrients, including antioxidant vitamins, and the three main types of cataract in older people. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Two thousand nine hundred people aged 49 to 97 years living in an urban community near Sydney, Australia. TESTING: Food frequency questionnaires and lens photography. MAIN OUTCOME MEASURE: Lens photographs were graded for presence and severity of cortical, nuclear, and posterior subcapsular cataracts. RESULTS: Higher intakes of protein, vitamin A, niacin, thiamin, and riboflavin were associated with reduced prevalence of nuclear cataract. After adjusting for multiple known cataract risk factors, the odds ratios for those in the highest intake quintile groups compared to those in the lowest intake quintiles were 0.5 (95% confidence interval [CI], 0.3-0.8) for protein, 0.5 (95% CI, 0.3-0.9) for vitamin A, 0.6 (95% CI, 0.4-0.9) for niacin, 0.6 (95% CI, 0.4-0.9) for thiamin, and 0.5 (95% CI, 0.3-0.9) for riboflavin. Intake of polyunsaturated fats was associated with reduced prevalence of cortical cataract. No nutrients were associated with posterior subcapsular cataract. CONCLUSIONS: The nucleus of the lens is particularly sensitive to nutrient deficiencies. Protein, vitamin A, niacin, thiamin, and riboflavin protected against nuclear cataract in this study.
Aged↗
The nature of bipolar depression: implications for the definition of melancholia.
AIM: To examine if melancholic depression is over-represented in those with 'bipolar depression' and, if confirmed, to use that phenomenon to assist the clinical definition of melancholia. METHODS: We contrast 83 bipolar and 904 unipolar depressed patients on three melancholic sub-typing systems (DSM, Clinical and CORE system) and compare representation of their clinical depressive features. RESULTS: By all three melancholic sub-typing systems, the bipolar patients were more likely to receive diagnoses of 'melancholia' and of psychotic depression. To the extent that this differential prevalence of depressive sub-types was reflected in varying patterns of clinical features, we so indirectly identified a set of items defining 'melancholia'. By such a strategy, melancholia was most clearly distinguished by behaviourally-rated psychomotor disturbance. While a number of 'endogeneity symptoms' were significantly over-represented, logistic regression analyses refined the set to psychomotor disturbance (both as a symptom and as a sign) and pathological guilt. We also established a distinctly higher prevalence of bipolar depression in those where a refined diagnosis of melancholia was made. CONCLUSIONS: Bipolar depression appears to be more likely to be 'melancholic' in type, thus providing an indirect strategy for the clinical definition of melancholia.
Adult↗
mRNA stability in eukaryotes.
During the past two years, the role of the proteins HuR and hnRNP D in regulated mRNA degradation in humans has become clearer, and a putative mRNA deadenylase, DAN or PARN, has been identified. In yeast, the relationship between translation and mRNA turnover is clearer, but the mRNA decapping process has turned out to be unexpectedly complex.
Animals↗
Twelve-month outcome of nonmelancholic depressive subjects: refinement of subgroups by examination of trajectories.
We previously studied a sample of patients with nonmelancholic depression and attempted to subtype their depression on the basis of etiological factors and current clinical features, analyzed individually and together. We now examine the validity of the three contrasting analytic approaches by examining outcome trajectories in a prospective study. At follow-up we reinterviewed 67% of our initially assessed nonmelancholic subjects, with progress over the 12-month interval assessed across a range of outcome parameters. The "anxious depressed" groups identified across all three differing analytic strategies consistently had the poorest 12-month outcome. However, varying definitions of this group influenced quite differing trajectories, with the worst outcome being for those defined on the basis of clinical features. Study results strongly suggest that patients presenting with a nonmelancholic depressive disorder and who acknowledge a significant number of concurrent anxiety symptoms are likely to have a distinctly poor medium-term outcome. Thus, clinical definition does have predictive utility in such a group.
Affect↗
Subtyping depression by clinical features: the Australasian database.
OBJECTIVE: To distinguish psychotic, melancholic and a residual non-melancholic class on the basis of clinical features alone. Previous studies at our Mood Disorders Unit (MDU) favour a hierarchical model, with the classes able to be distinguished by two specific clinical features, but any such intramural study risks rater bias and requires external replication. METHOD: This replication study involved 27 Australasian psychiatrist raters, thus extending the sample and raters beyond the MDU facility. They collected clinical feature data using a standardized assessment with precoded rating options. A psychotic depression (PD) class was derived by respecting DSM-IV decision rules while a cluster analysis distinguished melancholic (MEL) and non-melancholic classes. RESULTS: The MELs were distinguished virtually entirely by the presence of significant psychomotor disturbance (PMD), as rated by the observationally based CORE measure, with over-representation on only three of an extensive set of 'endogeneity symptoms'. CONCLUSION: In comparison to PMD, endogeneity symptoms appear to be poor indicators of 'melancholic' type, confounding typology with severity. Results again support the hierarchical model.
Adult↗
Seasonal variation in hospital admission for bipolar disorder, depression and schizophrenia in Tasmania.
OBJECTIVE: Seasonal variation has been reported for both affective disorders and schizophrenia. The current study examines seasonal variation in admissions in schizophrenia, depression and bipolar disorder in Tasmania, the southernmost state of Australia. METHOD: All admissions with a diagnosis of schizophrenia, bipolar disorder and depression in Tasmania between 1983 and 1989 were examined for evidence of seasonal variation in admission patterns. RESULTS: Using the modified Kolmogorov-Smirnov statistic defined by Freedman no significant seasonal variation was found in admissions with diagnoses of mania, depression or schizophrenia. There was a significant seasonal variation in admissions with schizoaffective disorder (winter peak). CONCLUSION: There is no significant seasonal variation in admissions with schizophrenia, depression or bipolar disorder in Tasmania. This may be due to a combination of geographical location and the stringent test of seasonal variation used in the current study.
Bipolar Disorder↗
Musing on the structural organization of the exosome complex.
The exosome complex of 3'-->5' exoribonucleases functions in both the precise processing of 3' extended precursor molecules to mature stable RNAs and the complete degradation of other RNAs. Both processing and degradative activities of the exosome depend on additional cofactors, notably the putative RNA helicases Mtr4p and Ski2p. It is not known how these factors regulate exosome function or how the exosome distinguishes RNAs destined for processing events from substrates that are to be completely degraded. Here we review the available data concerning the modes of action of the exosome and relate these to possible structural arrangements for the complex. As no detailed structural data are yet available for the exosome complex, or any of its constituent enzymes, this discussion will rely heavily on rather speculative models.
Allosteric Regulation↗
Predictors of 1-year outcome in depression.
OBJECTIVE: We compared several different methods for assessing depression 'recovery' over a 1-year review interval, to determine the utility of the contrasting approaches. Second, we assessed baseline predictors of 1-year outcome and recovery status. Third, we examined the extent to which predictors showed consistency across the variable definitions of outcome and recovery. METHODS: Twelve-month outcome was assessed in a sample of 182 subjects who at baseline assessment met DSM criteria for a major depressive episode. The contrasting methods involved a defined percentage reduction in Beck Depression Inventory self-rating scores, formalised change point definitions, no longer meeting DSM-IV major depression criteria, and clinical global improvement (CGI) ratings. RESULTS: Sixty-one per cent reached formalised change point criteria for full remission or recovery when trajectories across the 12-month interval were examined. Other measures quantified recovery rates ranging from 43% to 70%. Those with a psychotic or melancholic depression were more likely to have achieved recovery status in some analyses. Non-recovery at 12 months was predicted most consistently by higher baseline levels of anxiety and depression; high trait anxiety and a lifetime anxiety disorder; disordered personality function; and having reported exposure to acute and enduring stressors at baseline assessment. CONCLUSIONS: While the CGI was the superior system in terms of number of significant discriminating predictors of outcome, the change point definitional approach provides much greater information across the follow-up interval, arguing for their complementary utility. As several currently identified baseline predictors of outcome (i.e. anxiety, disordered personality function) also predicted onset of depression, their relevance as both depression-inducing and depression-propagating variables is suggested.
Adult↗
Risk factors and significance of finding asymptomatic retinal emboli.
PURPOSE: To assess the prevalence rates for asymptomatic retinal emboli among both younger and older individuals, with single and multiple potential risk factors, in order to alert clinicians to the probability of finding retinal emboli in patients with varying characteristics. METHODS: In all, 3654 people aged 49-97 attending the Blue Mountains Eye Study had a detailed eye examination which included retinal photographs of the central and peripheral retinal fields. Retinal emboli were identified during masked photographic grading and definite cases were adjudicated. RESULTS: Retinal emboli were found in 51 subjects (1.4% of the population); these included 1.1% of people aged 49-69 years (middle-aged subjects) and 2.0% of people aged more than 70 years (older subjects). Risk factors identified were male sex, increasing age, hypertension, current smoking, history of any vascular event (angina, myocardial infarct, stroke) or history of vascular surgery. Among middle-aged subjects, current smoking and history of hypertension or a vascular event were significantly associated with emboli (odds ratios (OR) 2.3-3.1), while in older subjects, history of vascular surgery was related (OR 4.7). The highest prevalence of emboli (5.5%) was found in people who reported a history of hypertension and also smoked (OR 6.0). Among hypertensive men who smoked, emboli were present in 7.6%. CONCLUSIONS: This study indicates that although asymptomatic retinal emboli are relatively infrequent in the general older population, these lesions are surprisingly common in people (particularly men) with multiple risk factors. Ophthalmologists could routinely screen for emboli and consider alerting the patients' general practitioners to review vascular risk factors.
Aged↗
Visual function tests, eye disease and symptoms of visual disability: a population-based assessment.
PURPOSE: To examine associations between eye disease and tests of visual function with self-reported visual disability. METHODS: The Blue Mountains Eye Study is a cross-sectional census-based survey of eye disease in two postcode areas in the Blue Mountains, west of Sydney, Australia. Of 4433 eligible residents, 3654 (82,4%) participated. Subjects had a detailed eye examination, including tests of visual acuity, contrast sensitivity, disability glare and visual field. Lens and retinal photographs were taken and graded according to standardized protocols for presence of cataract, early and late age-related maculopathy, glaucoma, diabetic retinopathy, retinal vein occlusion and other eye diseases. An interviewer-administered questionnaire included questions about perception of visual disability. RESULTS: Scores on all tests of visual function significantly decreased with age (P < 0.0001). This decrease persisted for all tests except disability glare after excluding subjects with identifiable eye disease. The presence of one or more eye diseases was significantly associated with all (self-reported) measures of visual disability (trouble driving at night, difficulty recognizing a friend across the street, reading a newspaper or recognizing detail on televsion): mixed cataract (cortical and nuclear, or posterior subcapsular and nuclear) was associated with trouble driving at night and difficulty recognizing a friend across the street. A 10-letter (two-line) decrease in best corrected or presenting visual acuity was significantly associated with all self-reported measures of vsual dsability, as was a two-step decrease in contrast sensitvity. A five-point increase in points missing in the visual field was weakly but significantly associated with all self-reported measures of visual disability except trouble driving at night. CONCLUSIONS: Visual function declines with age. Impaired visual function was strongly, and eye disease relatively weakly associated with reports of visual disability.
Aged↗
Projected number of Australians with visual impairment in 2000 and 2030.
This study aimed to project population-based prevalence data associated with visual impairment, in order to estimate the number of affected older Australians (aged 50 or older) in the years 2000 and 2030. We used data from the Blue Mountains Eye Study (BMES) and Melbourne Visual Impairment Project (MVIP), together with Australian Bureau of Statistics population projections. Similar definitions for moderate (6/24-6/60 visual acuity) and severe (< 6/60 visual acuity) visual impairment were used. Combining age-standardized data, we estimated that in the year 2000, 38 820 (0.73%) and 25590 (0.48%) Australians aged 50 years or older will have moderate and severe visual impairment, respectively. By 2030, these rates will have more than doubled, to an estimated 85910 (0.92%) and 57930 (0.62%) Australians with moderate and severe visual impairment, respectively. Women aged 50 years or older will have a 1.8-fold and four-fold risk, respectively, of moderate and severe visual impairment compared to men. Visual impairment will affect an increasing proportion of older Australians, Newer approaches to therapy, rehabilitation and community support for persons with visual impairment will be needed to meet this challenge.
Aged↗
Projected number of Australians with glaucoma in 2000 and 2030.
Accurate Australian glaucoma prevalence has been provided by two population-based studies: the Blue Mountains Eye Study (BMES) and the Melbourne Visual Impairment Project (MVIP). Both stud es defined glaucoma as the presence of matching optic disc cupp ng with rim thinning and g aucomatous field defects demonstrated on automated perimetry Combining 'definite' and 'probable' rates, the glaucoma prevalence in persons aged 50 and over, age-standardized for the 2000 projected Australian population, was 2.70% (BMES) and 3.13% (MVIP), including rates for 'definite' glaucoma of 2.12% (BMES) and 2.50% (MVIP). The number of Australians aged 50 and over in the year 2000 with g aucoma could be estimated as from 144 000 persons (BMES) to 167 000 persons (MVIP). Assuming similar age-specific rates, the number of Austral ans aged 50 and over in the year 2030 wth glaucoma could be estimated as from 307 000 persons (BMES) to 337 000 persons (MVIP). Ocular hypertens on (OH) was defined as present in subjects without glaucoma wth intraocular pressure (IOP) of more than 21 mmHg, including treated subjects with 'normal' examination IOP The age-standardized OH prevalence was 5.15% (BMES), which projects to 275000 Australians with OH in 2000, increasing to 513000 in 2030.
Aged↗
Age-specific prevalence and causes of bilateral and unilateral visual impairment in older Australians: the Blue Mountains Eye Study.
PURPOSE: To report age-specific prevalence and causes of bilateral and unilateral visual impairment in a representative older Australian population. METHODS: Participants in the Blue Mountains Eye Study (n = 3654) underwent a detailed eye examination. Any visual impairment was defined as best-corrected visual acuity (VA) of 6/12 or worse, moderate impairment as VA 6/24-6/60 and severe impairment as VA worse than 6/60 (the Australian definition for legal blindness). Bilateral visual impairment was defined from the better eye and unilateral impairment from the worse eye. Proportional causes for visual loss were determined by the examining ophthalmologist. RESULTS: Prevalence of bilateral and unilateral visual impairment was strongly age related. Corresponding bilateral and unilateral visual impairment prevalence rates were, respectively, 0.6% and 3.6% for persons aged 49-59 years, 1.1% and 8.2% for ages 60-69, 5.4% and 20.1% for ages 70-79, and 26.3% and 52.2% for persons aged 80+ years. Overwhelmingly, age-related maculopathy (ARM) was the predominant cause of bilateral blindness (13/17) and of moderate to severe bilateral visual impairment in persons aged 70+ years. However, cataract was the most frequent cause of mild bilateral visual impairment among persons aged 60+ years. Amblyopia was the most frequent cause of mild or worse unilateral visual impairment in persons aged 49-59 years. Cataract was the most common cause of mild unilateral visual impairment in people aged 60+ years, while ARM and cataract were jointly the most frequent causes of moderate to severe unilateral visual impairment in people aged 70+ years. CONCLUSIONS: These findings indicate that around half of visually impaired persons aged 60 years or over had cataract, a cause amenable to treatment.
Age Distribution↗