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PubMed1999

Validity of the Malaise Inventory in general population samples.

BACKGROUND: The Malaise Inventory is a commonly used self-completion scale for assessing psychiatric morbidity. There is some evidence that it may represent two separate psychological and somatic subscales rather than a single underlying factor of distress. This paper provides further information on the factor structure of the Inventory and on the reliability and validity of the total scale and two sub-scales. METHODS: Two general population samples completed the full Inventory: over 11,000 subjects from the National Child Development Study at ages 23 and 33, and 544 mothers of adolescents included in the Isle of Wight epidemiological surveys. RESULTS: The internal consistency of the full 24-item scale and the 15-item psychological subscale were found to be acceptable, but the eight-item somatic sub-scale was less reliable. Factor analysis of all 24 items identified a first main general factor and a second more purely psychological factor. Receiver operating characteristic (ROC) analysis indicated that the validity of the scale held for men and women separately and for different socio-economic groups, by reference to external criteria covering current or recent psychiatric morbidity and service use, and that the psychological sub-scale had no greater validity than the full scale. CONCLUSIONS: This study did not support the separate scoring of a somatic sub-scale of the Malaise Inventory. Use of the 15-item psychological sub-scale can be justified on the grounds of reduced time and cost for completion, with little loss of reliability or validity, but this approach would not significantly enhance the properties of the Inventory by comparison with the full 24-item scale. Inclusion of somatic items may be more problematic when the full scale is used to compare particular sub-populations with different propensities for physical morbidity, such as different age groups, and in these circumstances it would be a sensible precaution to utilise the 15-item psychological sub-scale.

Adult↗
PubMed2005

Methodological aspects of outcomes research.

A critical evaluation of existing scientific evidence of treatment efficacy can be an important part of communicating risk and benefits of treatment options to patients during the course of clinical practice. A checklist of key methodological issues to examine when reading a research study is presented and discussed. Steps in reading a paper include: identifying the research question; identifying the manner in which subjects get enrolled in the study; identifying the treatments and outcomes used; identifying the study design and the comparisons being made; evaluating the study methods for the possibility of bias and uncontrolled confounding; assessing whether the statistical analysis used is appropriate for the study design; assessing whether the study has sufficient statistical power to demonstrate hypotheses being tested. Finally, procedures for grading and evaluating evidence, as used by systematic review groups and international best evidence synthesis consensus groups is briefly described.

Back Pain↗
PubMed1996

Quantitative EEG in the prediction of antidepressant response to imipramine.

The purpose of this study was to examine the utility of quantitative electroencephalography (QEEG) in the prediction of response to imipramine in depressed patients. Forty patients with a diagnosis of unipolar depression were subjected to a placebo washout and were assessed at pre-drug, 3 h after their first dose of imipramine, and again 2 weeks into treatment. Following 4 weeks of open imipramine treatment, patients were separated into responder (R) and non-responder (NR) groups. Statistical analysis of the 29 patients who completed the study focused on group comparisons of power spectral estimates in four frequency bands from multi-channel recordings. Results showed that theta power differentiated R and NR groups prior to treatment, in response to an acute test dose, as well as after 2 weeks of active drug treatment. Results based on this exploratory study suggest that QEEG may be a useful early predictor of response to imipramine.

Adult↗
PubMed2005

Influence on the mechanisms of generation of distortion product otoacoustic emissions of mobile phone exposure.

Mobile phones have become very commonly used throughout the world within a short period of time. Although there is no clear evidence to show harmful physiological effects of electromagnetic fields (EMF) at the levels used by mobile phones, there is widespread public concern that there may be potential for harm. Because mobile phones are usually held close to the ear, it is appropriate to study effects on hearing. In this study, the outer hair cell function of 15 subjects was assessed by DPOAE recording before and after a controlled EMF exposure. To increase the sensitivity of DPOAE recording to identify even small changes in hearing function, an inverse fast Fourier transform (IFFT) analysis and time-domain windowing was applied to separate the two generation mechanisms of DPOAE, the so-called place-fixed and wave-fixed mechanisms, in order to verify if EMF can affects the two DPOAE emission mechanisms. Statistical analysis of the data showed that 10 min of EMF exposure at the maximum power (2 W at 900 MHz or 1 W at 1800 MHz) does not induce any changes in either DPOAE generation mechanism.

Adolescent↗
PubMed2005

Alzheimer disease is substantially preventable in the United States -- review of risk factors, therapy, and the prospects for an expert software system.

Epidemiology studies, including both regional incidence and the analysis of specific risk factors for Alzheimer's disease indicate that substantial prevention of the disease, in the 50-70 percent range, is a practical possibility for the United States. Epidemiology has identified a rich diversity of specific prevention strategies relating to nutrition, dietary supplements, lifestyle, food and environmental toxins, and in some cases medication, many of which have a capacity to reduce Alzheimer's risk by 50 percent or more. The interaction of these risk factors with brain biology is increasingly understood. In contrast, therapeutic strategies for un-prevented Alzheimer's generally prove incapable of delaying disease progression by more than 3-11 months, because extensive brain cell death occurs even in preclinical or mild cases. A public health program aimed at prevention can be fashioned with expert software packages, based on already identified risk factors. Such statistical analysis should allow the prediction of individual and group Alzheimer's risks of sufficient power to instruct the formulation of lifestyle, nutritional and environmental programs to substantially reduce disease incidence. A less satisfactory but complementary alternative is very early disease detection with therapeutic strategies focused on retardation of brain cell death, so that the person dies of another cause before the disease is clinically manifested.

Alzheimer Disease↗
PubMed2003

3D-QSAR studies on thieno[3,2-d]pyrimidines as phosphodiesterase IV inhibitors.

Cyclic nucleotide phosphodiesterase IV (PDE IV) inhibitors find utility in asthma and Chronic Obstructive Pulmonary Disease (COPD) therapy. A series of 29 thieno[3,2-d]pyrimidines with affinity for PDE IV was subjected to three dimensional quantitative structure activity relationship (3D-QSAR) studies using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). Both CoMFA and CoMSIA provided statistically valid models with good correlative and predictive power. The incorporation of hydrophobic, hydrogen bond donor and hydrogen bond acceptor fields showed insignificant improvement in CoMSIA model. The 3D-QSAR models provide information for predicting the affinity of related compounds and designing more potent inhibitors.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2004

GIS tools for tick and tick-borne disease occurrence.

Geographic information systems (GIS), their fundamental components and technologies are described. GIS is a computer-based system enabling the storage, integration, query, display and analysis of data using information on data location. Further, remote sensing (RS) methods and their application in landscape characterization are described. Landscape pattern analysis, combined with statistical analysis, allows the determination of landscape predictors of disease risk. This makes RS/GIS a powerful set of tools for disease surveillance, enabling the prediction of potential disease outbreaks and targeting intervention programs. The 'pre-GIS era' is briefly described including the early mapping of tick distribution, analyses and the display of biogeographical and medical data. The theory of natural focality of diseases (NFD) is explained and its significance in tick-borne diseases (TBD) research is discussed. Many problems of tick ecology and TBD epidemiology and epizootology have been addressed by means of GIS and examples of these studies are presented and discussed.

Animals↗
PubMed1980

A test for the radomness of the occurrence of a disease trait in familial or other similar ordered sequences of epidemiological data.

Through the construction of a probability distribution, a test is proposed for the randomness of the occurrence of an epidemiological event in a series of structured ordered sequences. Such sequences may be of persons admitted to hospital in some specified order, individuals seen in a large set of extended screening program, or individuals in a large set of extended genealogies. Modifications to account for the limited length of ascertained sequences are also given. The method will be particularly important in the first-stage evaluation of genealogical data to indicate the existence and degree of familial aggregation of diseases such as cancer and to justify more complex methods of analysis designed to evaluate the specific elements of causation that may be operating. The statistical power of this approach is also derived, considering the anticipated sample sizes in its application, to detect some forms of familial aggregation in a large genealogical data base from Laredo, Texas.

Age Factors↗
PubMedDate not supplied

Use of the spontaneous Tsc2 knockout (Eker) rat model of hereditary renal cell carcinoma for the study of renal carcinogens.

The kidney is a frequent site for chemically induced cancers in rodents and among the 10 most frequent sites for cancer in human patients. Renal cell carcinoma (RCC) is the most frequent upper urinary tract cancer in humans and accounts for 80-85% of malignant renal tumors. Hereditary RCC occurs in Eker rats that are heterozygous for an insertion mutation in the Tsc2 tumor suppressor gene. The germline mutation renders heterozygous mutants highly susceptible to renal carcinogens. The utility of this model in studying potential renal carcinogens is due to an ordered progression of proliferative renal lesions that can be identified and counted microscopically. The quantitative nature of the model allows for the production of statistically powerful data to understand the relative degree and potency of chemical effects and allow analysis of genetic alterations that may be chemical specific.

Animals↗
PubMed1994

Sex differences in measles mortality: a world review.

BACKGROUND: In general females have a lower mortality than males at all ages. Excess female mortality has been documented in certain high mortality situations, in particular in South Asia. However, females may have a higher mortality for certain causes of death. One of the causes of death for which excess female mortality is suspected is measles. METHOD: Sex differences in measles mortality are investigated using all national data on causes of death published by WHO since 1950. An index of excess mortality is used: the geometric mean of the female sex ratios of age-specific deaths rates from measles, from age 0 to 44 years. RESULTS AND CONCLUSIONS: When pooled together, the results show an excess of female mortality from birth until age 50 years. The excess female mortality appears small at age 0-4 (+4.2%), larger at age 5-14 (+10.9%) and peaks during the female reproductive period, at age 15-44 (+42.6%). This pattern of excess female mortality occurs in all the major regions of the world: Europe, North and South America, Far-East Asia, the Middle East and South Asia. The only noticeable exceptions are the Philippines and Thailand. The validity of the finding is extensively reviewed. Emphasis lies on the statistical power to prove that sex differences in measles mortality do exist, on the critical analysis of a case study in England and Wales, on the comparison with the overall pattern of sex differences and on available data on sex differences in incidence. Possible explanations are reviewed.

Adolescent↗
PubMed2006

Tongue-base suspension in conjunction with uvulopalatopharyngoplasty for treatment of severe obstructive sleep apnea: long-term follow-up results.

OBJECTIVES/HYPOTHESIS: To evaluate the usefulness of tongue-base suspension (TBS) in addition to uvulopalatopharyngoplasty (UPPP) in the treatment of obstructive sleep apnea syndrome (OSAS). STUDY DESIGN: Long-term prospective case series. SETTING: University tertiary care medical center. METHODS: Fifty-five consecutive patients with severe OSAS (apnea-hypopnea index [AHI] 52.8+/-14.9 events/hr) with multilevel upper airway obstruction who refused treatment with continuous positive airway pressure underwent UPPP plus TBS with the Repose system. All patients were evaluated before surgery by clinical history, Epworth Sleepiness Scale (ESS), fiberoptic nasopharyngoscopy with Müller maneuver, and nocturnal polysomnography (PSG). After 3 years of surgery, all patients were re-evaluated at the clinic and had ESS test and full PSG. Surgical success was defined when the ESS dropped bellow 11, and the AHI decreased below the threshold of 20 events per hour of sleep and at least 50% from the preoperative value RESULTS: There were 42 (78%) patients in which the AHI score decreased more than 50%, the AHI was lower than 20 events/hr in the PSG, and the ESS was lower than 11 after 3-years of follow-up (surgical success index). Logistic regression analysis demonstrated that body mass index at baseline was the only variable with significant statistical power to predict surgical success (odds ratio 0.85; 0.73-0.95, 95% confidence interval, P<.01) CONCLUSION: When associated with UPPP, the TBS technique performed with the Repose system demonstrates a surgical success of up to 78% for patients with severe OSA who refused nasal continuous positive airway pressure.

Female↗
PubMed2002

Adverse environmental impact: a consultant's perspective.

Environmental consultants are in a unique position to address the practical aspects of a working definition of "adverse environmental impact" (AEI) within Section 316(b) of the Clean Water Act. In our work with the electric utility industry, attorneys, and regulatory agencies, we have encountered numerous and sometimes conflicting interpretations as to what constitutes AEI. In our over 30 years of experience, we have applied most of the approaches suggested for addressing this issue, including biostatistical methods, trend analysis, time series methods, conditional mortality rate models, stock-recruitment models, equivalent adult models, and ecosystem models. In our experience, the paradigm most helpful in bringing about agreement among stakeholders is to (1) create a model of operating scenarios, (2) use empirical data from on-site studies to parameterize the model, (3) convert losses by life stage to equivalent adult losses, (4) convert equivalent adult losses to economic value, and (5) compare scenarios on an economic basis.

Consultants↗
PubMed1976

EEG and task performance after ACTH4-10 in man.

Effects of the heptapeptide ACTH4-10 (Org OI-63) on EEG, some memory tests, and behavior were examined in 12 normal male volunteers under 30 years of age. An intravenous dose of 60 mg was compared to placebo in a Latin square design. EEG was recorded for 2 h after administration of ACTH4-10 or placebo and was quantified by power spectral density analysis. Drug differences were tested by analyses of variance and covariance. No statistical drug effect was seen on the EEG or behavioral measures. Of the psychological tests, only the digit span test showed a decrease in number of errors with ACTH4-10 (p less than or equal to o.05). These results are consistent with previous studies and suggest that an intravenous bolus of ACTH4-10 has a limited effect on the brain function tested.

Adrenocorticotropic Hormone↗
PubMed1998

Large datasets: common uses and caveats.

BACKGROUND: Increasingly, large collections of pre-existing data are being used to analyze the occurrence, burden, and health care resources directed to the management of various skin diseases. OBJECTIVE: This article discusses a number of different types of large datasets along with their common uses. Various concerns about the use of this information are also discussed. CONCLUSION: Although large datasets provide significant statistical power with readily available data, there are significant concerns, particularly regarding data quality and statistical analysis. Readers need to be aware of how an investigator has addressed these issues. Furthermore, the profession needs to be cognizant of very legitimate public concerns regarding confidentiality of personal information.

Databases, Factual↗
PubMed2005

A prospective double-blind randomized controlled trial of the effect of topical bupivacaine on post-operative pain in bilateral nasal surgery with bilateral nasal packs inserted.

To ascertain whether local anaesthetic use is of clinical benefit in nasal surgery, a prospective double-blind randomized controlled trial of topical bupivacaine on post-operative pain in patients packed after bilateral nasal surgery was carried out. Each patient received a bupivacaine-soaked and a saline-soaked Merocel pack, thereby acting as their own control. Power analysis ascertained the number of patients required to enter the trial to detect a statistically significant difference in pain. Fifty-seven patients completed the trial. Visual analogue scales determined the level of post-operative pain at different time points in each nostril. Less pain was demonstrated in nostrils containing bupivacaine-soaked packs compared with saline-soaked packs at two hours (p < 0.0001), four hours (p = 0.0183) and six hours (p = 0.0476) post-operatively. Although not statistically significant, less pain was noted on pack removal on the local anaesthetic sides. These results provide clinical-based evidence for the use of bupivacaine as a local anaesthetic in reducing pain following nasal surgery with packing.

Adolescent↗
PubMed2001

Estimates of appropriate number of rats: interaction with housing environment.

An extensive list of physiological parameters from previous experiments was re-analysed in order to evaluate the effects of enrichment, cage type and group size on the within-group variation and hence on the number of animals needed in studies using Wistar rats. The independent factors studied in these experiments included the provision of aspen gnawing blocks for enrichment, solid bottom cages (SBCs) and grid floor cages (GFCs) and animal number per cage (varied from 1-4). SOLO power analysis was used to calculate the smallest number of animals (n) needed to detect an arbitrarily chosen 20% effect size, when significance was set at P = 0.05 and statistical power at 0.90. N ratios (nlarger/nsmaller) were calculated for the effect of enrichment, cage type and group size to compare the 'treatment group' with the 'control group'. The n values of adrenal gland, interscapular brown adipose tissue (BAT) and epididymal adipose tissue (EAT) weights seemed to vary most, whereas final body weight (FBWJ and growth seemed to be the least variable ones. According to one-sample t-test, the N ratios of most physiological parameters differed significantly from zero (except the ones of FBW) indicating that n values in 'treatment' and 'control' groups were unequal. The results indicate that some of the physiological parameters are susceptible to variability attributable to environmental modifications in general whereas some are not. Furthermore, they suggest that the variation of different parameters may vary from one experiment to another and between different environments thus hindering the estimations of appropriate number of animals.

Animal Husbandry↗