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PubMed2006

Sources of mercury wet deposition in Eastern Ohio, USA.

In the fall of 2002, an enhanced air monitoring site was established in Steubenville, Ohio as part of a multi-year comprehensive mercury monitoring and source apportionment study to investigate the impact of local and regional coal combustion sources on atmospheric mercury deposition in the Ohio River Valley. This study deployed advanced monitoring instrumentation, utilized innovative analytical techniques, and applied state-of-the-art statistical receptor models. This paper presents wet deposition data and source apportionment modeling results from daily event precipitation samples collected during the calendar years 2003-2004. The volume-weighted mean mercury concentrations for 2003 and 2004 were 14.0 and 13.5 ng L(-1), respectively, and total annual mercury wet deposition was 13.5 and 19.7 microg m(-2), respectively. Two new EPA-implemented multivariate statistical models, positive matrix factorization (PMF) and Unmix, were applied to the data set and six sources were identified. The dominant contributor to the mercury wet deposition was found by both models to be coal combustion (approximately 70%). Meteorological analysis also indicated that a majority of the mercury deposition found at the Steubenville site was due to local and regional sources.

Air Pollutants↗
PubMed2006

Serum autoantibodies to alpha-fodrin are present in glaucoma patients from Germany and the United States.

PURPOSE: Glaucoma is characterized by a progressive loss of retinal ganglion cells that results in a characteristic optic neuropathy associated with visual field loss. In previous studies, changes in the antibody profiles have been shown in the sera of patients with glaucoma, and these findings suggest a role for autoimmune involvement in the pathogenesis of glaucoma in some patients. The purpose of this study was to compare the antibody profiles against optic nerve antigens in patients with glaucoma in two different study populations from Germany and the United States. METHODS: One hundred twenty patients were included in the study, 60 from Germany and 60 from the United States: a control group (CTRL, n = 20), a group of patients with primary open-angle glaucoma (POAG, n = 20), and one group of patients with normal-pressure glaucoma (NPG, n = 20) from each country. Western blot analyses against bovine optic nerve antigens were used to detect the IgG antibody patterns present in the patients' sera. The complex antibody profiles were analyzed by multivariate statistical techniques. RESULTS: Complex IgG autoantibody repertoires were present in all patients with glaucoma as well as healthy subjects from both the German and the United States study population. A large similarity between all antibody profiles in both study populations was demonstrated in the number and frequency of both up- and downregulation of antibody reactivities in patients with glaucoma of both national cohorts. The multivariate analysis of discriminance found a significant difference between the glaucoma groups and healthy subjects against optic nerve antigens. As in previous studies, the NPG group revealed the highest variance from the control group (P < 0.01). Furthermore, a newly described antibody biomarker in both study populations was identified as alpha-fodrin. Western blot results revealed that there was an increased frequency and enhanced immunoreactivity to alpha-fodrin (120 kDa) in the sera of patients with NPG. The presence of alpha-fodrin autoantibodies were confirmed by ELISA, in which a highly elevated anti-alpha-fodrin titer in patients with NPG was found to be significantly greater than in the control subjects (P < 0.01) or age-matched patients with POAG (P < 0.04). CONCLUSIONS: Complex IgG antibody patterns against optic nerve antigens can be reproducibly identified in the serum of study populations from the United States and Germany. In both cohorts, patients with glaucoma have characteristic differences in serum autoantibody repertoires from those in control subjects. A newly described autoantibody to alpha-fodrin found in other neurodegenerative diseases such as Alzheimer's, further implicate a role for autoimmunity and the neurodegenerative processes in glaucoma. The high correspondence of the autoantibody patterns found in the study populations from different continents provides further evidence that serum autoantibody patterns may be useful biomarkers for glaucoma detection or for determining prognosis in future studies by means of pattern-matching algorithms.

Aged↗
PubMed2006

Statistical dissection of genetic pathways involved in prostate carcinogenesis.

Molecular markers that could stratify prostate cancer patients according to risk of disease progression would allow a significant improvement in the management of this clinically heterogeneous disease. In the present study, we analyzed the genetic profile of a consecutive series of 51 clinically confined prostate carcinomas and 27 benign prostatic hyperplasias using comparative genomic hybridization (CGH). We then added our findings to the existing literature data in order to perform a meta-analysis on a total of 294 prostate cancers with detailed CGH and clinicopathological information, using multivariate statistical methods that included principal component, hierarchical clustering, time of occurrence, and regression analyses. Whereas several genomic imbalances were shared by organ-confined, locally invasive, and metastatic prostate cancers, 6q and 10q losses and 7q and 8q gains were significantly more frequent in patients with extra-prostatic disease. Regression analysis indicated that 8q gain and 13q loss were the best predictors of locally invasive disease, whereas 8q gain and 6q and 10q losses were associated with metastatic disease. We propose a genetic pathway of prostate carcinogenesis with two distinct initiating events, namely, 8p and 13q losses. These primary imbalances are then preferentially followed by 8q gain and 6q, 16q, and 18q losses, which in turn are followed by a set of late events that make recurrent and metastatic prostate cancers genetically more complex. We conclude that significant differences exist in the genetic profile of organ-confined, locally invasive, and advanced prostate cancer and that genetic features may carry prognostic information independently of Gleason grade.

Aged↗
PubMed1988

Identification of best electrocardiographic leads for diagnosing left ventricular hypertrophy by statistical analysis of body surface potential maps.

In view of the increased risk of cardiovascular mortality associated with left ventricular (LV) hypertrophy, early recognition and quantitation of LV hypertrophy are important clinical goals. The standard 12-lead electrocardiogram is the easiest and most widely used noninvasive method for the diagnosis of LV hypertrophy; unfortunately, the diagnostic accuracy of commonly used electrocardiographic criteria remains unsatisfactory. Body surface potential maps contain diagnostic information not present in conventional lead systems. The present investigation combines the increased information content of surface maps with the power of multivariate statistical techniques in order to identify practical subsets of electrocardiographic leads that would allow improved diagnosis of LV hypertrophy. Discriminant analysis was performed on 120-lead data simultaneously recorded in 250 normal subjects and 214 patients with LV hypertrophy using as features instantaneous voltages on time-normalized P, PR, QRS and ST-T waveforms as well as the duration of these waveforms. Leads and features for optimal separation of 173 normal subjects aged greater than or equal to 30 years from 122 patients with pure LV hypertrophy were selected. A total of 6 features from 5 torso sites accounted for a specificity of 97% and a sensitivity of 94%. The single most potent discriminator was the duration of the P wave; voltages were measured in mid and late P on leads located in the lower left parasternal area, the left precordial region and the upper right back, in mid-QRS on a lead positioned 10 cm below V1 and slightly before the peak of the T wave on a lead in the lower left flank.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Discriminant analysis of the standard 12-lead ECG for diagnosing non-Q wave myocardial infarction.

Discriminant analysis was performed on 12 standard lead data from 159 normal subjects (N) and 304 patients with first myocardial infarction (MI): the latter group consisted of 543 patients with acute non-Q wave MI (NQMI-group A), 68 patients with acute Q wave MI (QMI-group B) and 183 patients (group C) with recent (29) or old (154) QMI. A discriminant function was computed to separate optimally the larger group of QMI patients (group C) from N. A total of 7 features accounted for a specificity of 92% and a sensitivity of 89%. The classification model was then tested on patients with acute MI, regardless of the presence of Q waves (groups A and B); rates of correct classification were 72% for acute NQMI and 85% for acute QMI. The best measurements were voltages in the late portion of the T wave in aVR, V1 and V5, in early and late QRS in V2, at mid-QRS in lead II and in the second half of the P wave in V1. A weighted combination of these features with the coefficients of the discriminant function produced individual discriminant scores for each subject. Group-mean scores were 1.82 for N, -1.27 for acute QMI, -1.14 for old QMI and -.44 for acute NQMI, indicating that acute NQMI was "closer" to N than both acute and old QMI. QRS measurements from the 12-lead ECG were also used to derive the 45 criteria/33 point Selvester score in 53 patients with NQMI: 32% of NQMI were classified as MI with a score of 3 points or more (corresponding to a posterior probability greater than .50). These results were compared with those achieved by multivariate analysis using only QRS measurements: 56% of NQMI were classified as MI with a posterior probability threshold greater than .50. Associating a point score greater than or equal to 1 with criteria for ST-T abnormalities yielded a sensitivity of 72% at a specificity level of 95%. The results emphasize the presence of diagnostic information outside the initial part of QRS, the power of multivariate statistical procedures applied on continuous measurements and the potential benefit of discriminant scores for quantitative assessment of myocardial infarction.

Discriminant Analysis↗
PubMed2002

Diagnostic value of the RR-variability indicators for mild hypertension.

Experimental and clinical studies have shown that an imbalance of the cardiovascular system autonomous regulation can lead to complications. In this study we have aimed to investigate whether the vegetative control of patients with mild hypertension is disturbed and to evaluate the power of the RR-variability indicators to detect the disturbances. RR variability has been studied in two groups of individuals: normotensive and mildly hypertensive. The indicators of the heart rate variability (HRV) from the 'Cardiovit CS-100 ECG Module' electrocardiograph have been used. The HRV is known to exhibit circadian variations, therefore RR intervals were recorded in two separate sessions: morning (8-9 am) and afternoon (2-3 pm). Each session included three tests: in a resting state, with a handgrip test and with the Valsalva manoeuvre. The multivariate statistical method was applied separately to the morning and afternoon data. A number of classification algorithms were synthesized, yielding correct recognition of normotensive and mildly hypertensive subjects of 91.9% and 94.2% for the morning and afternoon sessions, respectively. We have thoroughly discussed the substantiating reasons for the high statistical significance and reliability of the discrimination obtained. The high sensitivity and specificity of the RR-variability indicators included in the classification models suggest correlative changes of the nervous system vegetative balance in mildly hypertensive patients. The results of the study show the possibility for statistically significant diagnosis of mild hypertension, for prediction of ventricular arrhythmia, left ventricular hypertrophy and ischaemic heart disease.

Adult↗
PubMed1994

Artificial intelligence versus logistic regression statistical modelling to predict cardiac complications after noncardiac surgery.

The traditional approach to developing models predictive of cardiac events has been to perform logistic regression (LR) analysis on a variety of potential predictors. An alternative to use an artificial intelligence system called a neural network (NN) which simulates biological intelligence. To evaluate the potential applicability of the latter method, we compared the ability of LR and NN techniques to predict cardiac events after noncardiac surgery. A total of 200 patients (training group) underwent cardiac risk assessment before major noncardiac surgery using 17 clinical parameters and 7 quantitative indices based on dipyridamole-thallium imaging. There were 21 post-operative myocardial infarctions and/or cardiac deaths. Data from the training group were used to develop two predictive models: one based on backward stepwise LR multivariate statistical analysis and the other one using a neural network. Both models were then validated on a second group of 160 consecutive patients also referred for preoperative risk stratification (validation group). The NN consisted of 14 input, 29 hidden, and 1 output neurons and used a back-propagation algorithm (learning rate 0.2, training tolerance 0.5, sigmoid transfer function). The sensitivity, specificity, positive and negative predictive accuracies for the prediction of postoperative events in the validation group of 160 patients were, respectively, 67% (6/9), 82% (124/151), 18% (6/33), and 98% (124/127) for LR, and 67% (6/9), 96% (145/151), 50% (6/12), and 98% (145/148) for the NN, with a difference in specificity which attained statistical significance (p < 0.01). Artificial intelligence may provide a useful alternative to conventional LR statistical analysis for the purpose of preoperative cardiac risk assessment.

Artificial Intelligence↗
PubMed2005

Development of a ligand knowledge base, part 1: computational descriptors for phosphorus donor ligands.

A prototype collection of knowledge on ligands in metal complexes, termed a ligand knowledge base (LKB), has been developed. This contribution describes the design of DFT-calculated descriptors for monodentate phosphorus(III) donor ligands in a range of representative complexes. Using the resulting data, a ligand space is mapped and predictive models are derived for metal complexes. Important characteristics, including chemical, computational and statistical robustness for the generation and exploitation of such an LKB are described. Chemical robustness ensures transferability of the descriptors, as well as comprehensive sampling of ligand space. To make the calculations amenable to automation in an e-science setting, a reliable, well-defined computational approach has been sought from which the descriptors can be readily extracted. The LKB has been explored with multivariate statistical methods. Principal component analysis (PCA) is used for the mapping of chemical space, projecting multiple descriptors into scatter plots which illustrate the clustering of chemically similar ligands. Interpretation of the resulting principal components in terms of established steric and electronic properties and the importance of its statistical robustness to variations in the ligand set are discussed. Multiple linear regression (MLR) models have been derived, demonstrating the versatility of the descriptors for modeling varied experimentally determined parameters (bond lengths, reaction enthalpies and bond-stretching frequencies). The importance of re-sampling methods for testing the robustness of predictions is highlighted. A strategy for the construction of a robust LKB suitable for the modeling of ligand and complex behavior is outlined based on these observations.

Journal Article↗
PubMed1982

Scientific inquiry in forensic psychiatry.

Forensic psychiatry and psychology, with an extensive history of clinical practice, is only recently emerging as a new scientific specialty. It is confronted with both general scientific-methodological issues, as well as unique, empirically-based psycholegal applications. Aimed towards a broader, more flexible paradigm for understanding the basis of our scientific inquiry, the paper examines various research and methodological issues. As a model for connecting and understanding these complicated and interrelated issues, Holton's explicit and useful model of scientific structure is provided. The methodology, logical and statistical analysis, and themata are explored with regards to their potential impact on scientific inquiry in forensic psychiatry. This paper argues for several considerations in furthering research. From a methodological basis, the prospective researcher has to consider (1) whether the methodology is, in part, predetermining the results; (2) whether the results are a prediction of the inclusion criteria rather than an independent finding; (3) what balance between specificity and generalizability is designed within the research study; and (4) what is the impact of various methodological artifacts on the results and conclusions of forensic psychiatric research (e.g., demand characteristics, evaluation apprehension, experimenter bias, systems influence). Further, the forensic psychiatric researcher is asked to consider the basis of the "validity" of his research findings in comparison with "objective reality" from the perspective of logical and statistical analysis. Scientists within forensic psychiatry are asked to consider (1) whether to employ "best fit" or complementarity in understanding their results; (2) how to make explicit the steps in data transformation and redefinition within their study; (3) what are the implications of exclusive use of null hypothesis testing in establishing research results; and (4) what is the comparative utility of non-parametric and multivariate statistical procedures in studying and understanding experimental variables. Finally, in acknowledging the non-linear and sometimes self-justifying aspect of science, researchers are invited to examine their basic assumptions, and the self-perpetuating and constraining nature of unacknowledged themata, as well as their impact on forensic psychiatry. This paper is conceptualized as a movement towards articulating both general methodological issues and their unique application to forensic psychiatry. The brief exposition of Holton's model and review of illustrative research in forensic psychiatry constitutes one attempt to strengthen the scientific rigor of forensic psychiatric research.

Forensic Psychiatry↗
PubMed2002

[Efficacy and safety of sildenafil in patients with erectile dysfunction and hypertension. Prognostic factors].

BACKGROUND: Our purpose was to assess the efficacy and safety of sildenafil as a treatment for erectile dysfunction in hypertensive patients, and to investigate those factors associated with a treatment failure. PATIENTS AND METHOD: Open, prospective study including 114 patients suffering from erectile dysfunction plus arterial hypertension who were evaluated by anamnesis, physical examination, blood tests including glycemia and lipidic and hormonal profiles, penile colour Doppler ultrasonography after intracavernosal prostaglandin E1 (PGE1) injection, and the Sexual Health Inventory for Men (SHIM). Efficacy of sildenafil was assessed by administering again the SHIM and by means of a global assessment questionnaire. Side effects were also recorded. Factors influencing treatment outcome were evaluated by univariate and multivariate statistical analysis. RESULTS: Overall, sildenafil was effective in 59.2% of 103 eligible patients. Efficacy in patients with psychogenic erectile dysfunction was 75%, whereas in those with an organic etiology, the efficacy was 50.7%. Age, diabetes mellitus, nocturnal penile tumescence, response to intracavernosal PGE1 injection and erectile dysfunction severity (defined by the SHIM basal score) significantly influenced treatment response (p < 0.05) after an univariate analysis. The multivariate analysis, however, selected only diabetes mellitus and severity of erectile dysfunction as the prognostic factors. No severe side effects were noticed. CONCLUSIONS: Sildenafil is a rather effective and well-tolerated treatment for erectile dysfunction in hypertensive patients. Baseline severity of erectile dysfunction and diabetes mellitus represent the prognostic factors most significantly associated with treatment outcome.

Erectile Dysfunction↗
PubMed2000

Ovarian cancer. an institutional review of patterns of care, health insurance and prognosis.

The purpose of this study was to investigate the prognostic importance of the health insurance status in 145 consecutive patients with ovarian cancer diagnosed between 1984 and 1996. All patients had basic (Type III) insurance to cover outpatient treatment and hospital expenses for a per diem flat fee; some patients had one of two types of supplemental private insurance (Type I and Type II) to cover the treatment by physicians of their choice and fee-for-service hospital treatment. The prognostic impact of health insurance was evaluated by multivariate statistical methods. The median follow-up was 81.9 months (range: 21-181); the 5-year probability of survival was 72% (standard error of the mean (SEM) 9.8%) for stage I, 53% (SEM 16.2%) for stage II, 17% (SEM 5. 9%) for stage III and 11% (SEM 5.5%) for stage IV cancer. Age, stage, histological grade and debulking surgery were independent predictors of survival in multivariate proportional hazards regression analysis. Patients with private insurance were younger and received more chemotherapy than patients with basic insurance. In multivariate analysis, insurance was an independent predictor of survival: patients with Type II insurance had a hazard ratio of 2.31 (95% confidence interval (CI): 1.05-5.04), and patients with Type III insurance had a hazard ratio of 3.30 (95% CI 1.52-7.17) compared with the reference group of Type I insured patients. Health insurance status was an independent predictor of survival in ovarian cancer. Research is needed to devise strategies to improve the medical care of patients with basic insurance.

Adult↗
PubMed1997

Variation during autorefraction: influence of two different target types.

An investigation was performed on seven subjects of varying ages in order to determine the influence of two different target types on autorefractor results. A single autorefractor capable of presenting two different targets was used. Multivariate statistical methods which only recently have become available in optometry are used to illustrate graphically the results obtained and formal hypothesis tests further demonstrate that most of the eyes in the sample display similar variation or behaviour with both targets. The mean refractive state likewise is not significantly different for both targets for five of the seven eyes at a 99% confidence level. Departures from multivariate normality (such as resulting from outliers) are shown to be of great importance in order to reach appropriate decisions with respect to target influence on autorefractor measurements and an example is provided to illustrate this point. In the absence of departures from normality it is believed that this study exhibits only weak evidence for differences in variation or mean refractive state with the different target types.

Adolescent↗
PubMed2004

[Analyses of the allogeneic stem cell transplantation outcome based on the new risk classification].

To disclose the information for the risk in allogeneic hematopoietic stem cell transplantation (allo-HSCT), we propose a new concept of the risk in allo-HSCT. We analyzed all 94 allo-HSCT cases (86 patients) in our hospital since 1983. The overall survival rate was 56.4%. Among 27 patients considered to be at standard risk judged by conventional risk criteria who underwent initial transplantation from HLA-identical donors, 66.7% of them survived. Univariate statistical analyses among subgroups classified by conventional risk criteria and several reported prognostic factors show significant differences. However, all of them failed to show significant difference because of too much variation between cases in the same subgroup or a too small number of patients as compared with the U.S.A or European transplantation centers. We propose an alternative comprehensive classification of transplantation risk according to two newly-recognized distinct risks, disease state and transplantation risk. This comprehensive classification revealed significance in the multivariate statistical analyses in our hospital. We expect further discussion or the appearance of other beneficial nationwide proposals to evaluate and disclose the risk affecting survival following allo-HSCT.

Adolescent↗
PubMed2003

Preoperative and operative predictors of delayed neurologic deficit following repair of thoracoabdominal aortic aneurysm.

PURPOSE: Delayed neurologic deficit has been recognized in recent years as a source of morbidity following thoracic and thoracoabdominal aortic repair. We wanted to find risk factors specifically significant for delayed neurologic deficit. In this initial study we looked at preoperative and operative risk factors. METHODS: We performed 854 thoracoabdominal aortic repairs between February 1991 and May 2001. For this study we excluded 26 patients who died before postoperative neurologic status could be evaluated and 38 who had immediate neurologic deficit on initial postoperative evaluation, leaving 790 consecutive patients. We evaluated a wide range of demographic, preoperative physiological and intraoperative data, using univariate and multivariable statistical analyses. RESULTS: Twenty-one of 790 (2.7%) patients had delayed neurologic deficit. Significant univariate predictors included preoperative renal dysfunction (odds ratio 5.9; P <.006), acute dissection (odds ratio 3.9; P <.05), extent II thoracoabdominal aorta (odds ratio 3.0; P <.03), and use of adjuncts (cerebrospinal fluid drainage and distal aortic perfusion; odds ratio 7.7; P <.03). The use of the adjuncts dropped from the multivariable model but all other factors remained. No other significant risk factors were identified. Twelve of 21 (57%) patients recovered neurologic function with optimization of blood pressure and cerebrospinal fluid drainage. CONCLUSION: Preoperative renal dysfunction, acute dissection, and extent II thoracoabdominal aorta are significant predictors of delayed neurologic deficit. Previous studies have demonstrated that the use of adjuncts protects against immediate neurologic deficit. The findings of this study are consistent with the hypothesis that adjuncts reduce ischemic insult enough to prevent immediate neurologic deficit but that a period of increased spinal cord vulnerability persists several days postoperatively.

Adolescent↗
PubMed1999

Evaluation of serum levels of solubilized adhesion molecules and cytokine receptors in coronary heart disease.

OBJECTIVES: The diagnostic importance of circulating solubilized tumor necrosis factor-alpha receptor II (sTNF-alphaRII) and interleukin-2 receptor in coronary heart disease (CHD) was evaluated. In addition, these variables were correlated with solubilized adhesion molecule levels (i.e., intracellular adhesion molecule [ICAM], vascular cell adhesion molecule [VCAM], and E-selectin). BACKGROUND: Atherosclerosis is considered to be a chronic inflammatory process. Because the immunologic network presents an abundance of positive and negative feedback mechanisms, information obtained from different immunologic variables might be highly redundant. METHODS: In a cross-sectional study design, 60 patients with angiographically proven CHD were compared with 60 individuals who had undergone coronary angiography but in whom no evidence of stenosis could be found (control subjects). Angiography was performed at least one year before the study. Cytokine levels were determined by enzyme-linked immunosorbent assay technique and evaluated by univariate and multivariate statistical methods. RESULTS: All immunologic variables except E-selectin (p = 0.08) significantly discriminated between patients and control subjects. Coronary artery bypass graft surgery after angiography did not lead to significant differences in the variables investigated in the patients with bypass surgery as compared with the subjects without bypass surgery. Receiver-operating characteristics analysis showed comparable test accuracy for solubilized adhesion molecules and cytokine receptors. Multivariate logistic regression analysis, including age, revealed that only ICAM and sTNF-alphaRII were independently correlated with the presence of CHD. Patients belonging to the third tertile of at least one of these two variables demonstrated a 1.6- to 2-fold increased relative risk for the presence of CHD. CONCLUSIONS: We concluded that both circulating ICAM and TNF-alphaRII should be further evaluated as markers for atherosclerotic changes in the coronary system.

Adult↗
PubMed1993

The effects of age, gender, race and concomitant disease on postoperative complications.

The purpose of this study was to identify factors from simple past medical history which could alert surgeons to patients at increased risk of postoperative complications. Five hundred and fourteen patients undergoing elective surgery were studied prospectively. Factors evaluated included the patients' age, gender, race and the presence in the past medical history of coronary artery disease, congestive heart failure, cardiac dysrhythmias, respiratory disease, endocrine disease, peripheral atherosclerosis, renal disease, neuropsychiatric disease, hypertension, diabetes mellitus, prior major surgery and prior or active malignancy. All complications were recorded. The data were analysed by univariate and multivariate statistical methods. Gender, race and age were not associated with any complications. Coronary artery disease, respiratory disease, atherosclerotic peripheral vascular disease, neuropsychiatric disease, malignancy, the absence of prior major surgery, hypertension and diabetes mellitus were associated with specific postoperative complications by univariate analysis. Malignancy, diabetes mellitus, peripheral atherosclerosis, coronary artery disease, neuropsychiatric disease, renal disease and respiratory disease were independent predictors of complications as determined by multivariate analysis. Of interest is the phenomenon that the risk of postoperative complications when a combination of risk factors was present was greater than what would be predicted by the cumulative risk of these factors. This study helps identify those patients which by simple history may be at increased risk of postoperative complications and may require aggressive preoperative evaluation.

Age Factors↗
PubMed1998

Anxiety disorders in later life: a report from the Longitudinal Aging Study Amsterdam.

OBJECTIVE: To study the prevalence and risk factors of anxiety disorders in the older (55-85) population of The Netherlands. METHOD: The Longitudinal Aging Study Amsterdam (LASA) is based on a random sample of 3107 older adults, stratified for age and sex, which was drawn from the community registries of 11 municipalities in three regions in The Netherlands. Anxiety disorders were diagnosed using the Diagnostic Interview Schedule in a two-stage screening design. The risk factors under study comprise vulnerability, stress and network-related variables. Both bivariate and multivariate statistical methods were used to evaluate the risk factors. RESULTS: The overall prevalence of anxiety disorders was estimated at 10.2%. Generalized anxiety disorder was the most common disorder (7.3%), followed by phobic disorders (3.1%). Both panic disorder (1.0%) and obsessive compulsive disorder (0.6%) were rare. These figures are roughly similar to previous findings. Ageing itself did not have any impact on the prevalence in both bivariate and multivariate analyses. The impact of other factors did not change much with age. Vulnerability factors (female sex, lower levels of education, having suffered extreme experiences during World War II and external locus of control) appeared to dominate, while stresses commonly experienced by older people (recent losses in the family and chronic physical illness) also played a part. Of the network-related variables, only a smaller size of the network was associated with anxiety disorders. CONCLUSIONS: Anxiety disorders are common in later life. The risk factors support using a vulnerability-stress model to conceptualize anxiety disorders. Although the prevalence of risk factors changes dramatically with age, their impact is not age-dependent. The risk factors indicate which groups of older people are at a high risk for anxiety disorders and in whom active screening and treatment may be warranted.

Aged↗
PubMed1988

Vision following helium ion radiotherapy of uveal melanoma: a Northern California Oncology Group study.

One hundred eighty-six uveal melanoma patients were treated with helium ion radiotherapy at Lawrence Berkeley Laboratory and followed for at least 6 months. (Follow-up times ranged from 6 to 90 months; median 26.4 months.) At last examination, 92 of 186 patients (49%) had visual acuity of 20/200 or better in the treated eye. Univariate statistical analysis revealed that post-treatment vision correlated with tumor size, distance between tumor and optic disc, distance between tumor and fovea, pretreatment visual acuity, dose delivered to the optic disc, and dose delivered to the fovea (p less than .05). Neither the maximum tumor dose nor site of tumor origin (ciliary body vs. choroid) correlated with post-treatment vision on a univariate basis. However, multivariate statistical analysis revealed that the strongest independent risk factors influencing vision outcome (p less than .05) were tumor size, pretreatment visual acuity, tumor-fovea distance, and maximum tumor dose. Neither the fovea dose nor the dose to optic disc appeared to significantly affect vision outcome when other variables were taken into account. These results suggest that post-treatment visual acuity of 20/200 or better can be achieved in one-half of uveal melanoma patients treated using helium ion irradiation. Several independent risk factors affecting vision outcome have been identified.

Helium↗