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PubMed1990

Multivariate analyses of carbohydrate data from lipopolysaccharides of Actinobacillus (Haemophilus) actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus.

The taxonomic distinction between Actinobacillus (Haemophilus) actinomycetemcomitans and Haemophilus aphrophilus and the taxonomic distinction between H. aphrophilus and Haemophilus paraphrophilus have been questioned. This study was done to determine whether multivariate statistical analyses of carbohydrate data from lipopolysaccharides could be used to distinguish between these closely related species. Lipopolysaccharides were extracted with phenol-water and purified. Carbohydrates were assessed by using gas chromatography and gas chromatography-mass spectrometry after methanolysis and derivatization with trifluoroacetic acid anhydride. The lipopolysaccharides from all of the species contained rhamnose, fucose, galactose, glucose, L-glycero-D-mannoheptose, and glucosamine plus galactosamine, but in varying amounts. A. actinomycetemcomitans and H. paraphrophilus also contained D-glycero-D-mannoheptose, while H. aphrophilus did not. Sample- and variable-oriented principal-component analyses of the carbohydrate data clearly distinguished among A. actinomycetemcomitans, H. aphrophilus, and H. paraphrophilus. Soft independent modelling of class analogy showed that no sample in the A. actinomycetemcomitans class fell within the 95% confidence limits of the H. aphrophilus class. H. paraphrophilus fell outside both classes.

Actinobacillus↗
PubMed2005

Burnout in clinical research coordinators in the United States.

PURPOSE/OBJECTIVES: To assess burnout among clinical research coordinators (CRCs) and to determine which personal and job-related factors are associated with burnout. DESIGN: Random, stratified, cross-sectional mail survey. SETTING: CRCs from membership lists of clinical research organizations. SAMPLE: 252 CRCs in the United States. To be included in the study, participants must have been in their current position longer than six months and involved in clinical trial coordination or data management. Of 2,770 records, 900 CRCs were mailed questionnaires; 35% (316) responded, and 252 of those were eligible for analysis. Eligible respondents were Caucasian (86%), female (94%), and employed full-time (92%) in an oncology setting (71%). METHODS: Respondents completed mailed self-administered questionnaires measuring burnout, job satisfaction, personality characteristics, perceived work overload, and selected personal- and employment-related data. Data analyses included descriptive, univariate, and multivariate statistics. MAIN RESEARCH VARIABLE: Burnout. FINDINGS: About 70% of respondents were satisfied with their job, and 74% would still choose the clinical research profession. Approximately 44% reported high emotional exhaustion, a component of burnout. Factors independently associated with high emotional exhaustion burnout were low satisfaction with job (p 0.0001), high perceived daily workload (p 0.0001), and low endurance personality (p = 0.002). CONCLUSIONS: Burnout is prevalent in CRCs. Job dissatisfaction, perceived daily work overload, low endurance, and nurturance personality traits were associated with high burnout. IMPLICATIONS FOR NURSING: Nurses are involved significantly in clinical trial coordination. High burnout rates have potentially negative implications for data quality and productivity in clinical trial data management-important values for nursing and the clinical research profession.

Administrative Personnel↗
PubMed2003

Is health care spending higher under Medicaid or private insurance?

This paper addresses the question of whether Medicaid is in fact a high-cost program after adjusting for the health of the people it covers. We compare and simulate annual per capita medical spending for lower-income people (families with incomes under 200% of poverty) covered for a full year by either Medicaid or private insurance. We first show that low-income privately insured enrollees and Medicaid enrollees have very different socioeconomic and health characteristics. We then present simulated comparisons based on multivariate statistical models that estimate the effects of private and Medicaid coverage on the likelihood of using services, and the level of expenditures, given any use, holding constant demographic, economic, and health status characteristics. The simulations demonstrate that if people with Medicaid coverage--with their health status, disability, and chronic conditions--were given private coverage, they would cost considerably more than they do today. Conversely, if the privately insured were given Medicaid coverage, spending would be lower. We find no evidence that spending differences between Medicaid and private coverage for low-income people are due to lower service use by Medicaid beneficiaries. We conclude that most of the difference in expenditures is due to differences in provider payment rates.

Acute Disease↗
PubMed1992

Frequency domain models of the EEG.

The structure of the normal resting EEG crosspectrum SVV(omega) is analyzed using complex multivariate statistics. Exploratory data analysis with Principal Component Analysis (PCA) is followed by hypothesis testing and computer simulations related to possible neural generators. The SVV(omega) of 211 normal individuals (ages 5 to 97) may be decomposed into two types of processes: the xi process with spatial isotropicity reflecting diffuse, correlated cortical generators with radial symmetry, and processes that seem to be generated by more spatially concentrated, correlated sources. The latter are reflected as spectral peaks such as the process. The eigenvectors of the xi process are the Spherical Harmonic Functions which explains the recurring pattern of maps characteristic of the spatial PCA of qEEG data. A new method for estimating sources in the frequency domain which fits dipoles to the whole crosspectrum is applied to explain the characteristics of the localized sources.

Age Factors↗
PubMed1997

Concept of segmentation in nosocomial epidemiology: epidemiological relation among antimicrobial-resistant isolates of Pseudomonas aeruginosa.

Typing studies on 271 clinical strains of Pseudomonas aeruginosa isolated from the University Teaching Hospital were conducted to obtain their serotypes, antimicrobial susceptibility patterns and plasmid profiles. These strain typing data were arranged through multivariate statistical analysis by computation to classify individual strains. Plots in the scatter diagrams obtained from both principal component analysis and quantification theory type III expressed the clinical strains of P. aeruginosa with various degrees of antimicrobial resistance. Epidemiological relation among these clinical strains was analysed in those scatter diagrams by segmentation, in combination with their epidemiological information (date and place of isolation, type of specimen, etc.). The results showed that the serotype E strains both with high-level resistance to gentamicin and with a plasmid of 3.9 x 10(6) dalton, and the strains resistant to more than five antimicrobial agents, were colonized and localized each in certain clinical wards for inpatients. It was suggested that segmentation analysis could be of practical use in the management of nosocomial infection control against P. aeruginosa with antimicrobial resistance.

Cluster Analysis↗
PubMed2006

Application of NMR-based metabonomics in the investigation of myocardial ischemia-reperfusion, ischemic preconditioning and antioxidant intervention in rabbits.

NMR based metabonomics was applied in rabbit plasma samples during myocardial ischemia-reperfusion injury, with the following interventions: (1) Control (no intervention); (2) ischemic preconditioning (IpC); (3) administration of melatonin; (4) IpC+administration of melatonin; (5) treatment of the indole derivative C6458. The (1)H NMR signal intensity ratio of lactate/glucose was found to increase in Control samples during reperfusion compared to baseline, while lactate+alanine/acetate was decreased suggesting impairment of aerobic glycolysis and concomitant lipid utilization. In contrast, after IpC or treatment with C6458, the lactate/glucose ratio was similar to baseline in accordance with the previously reported decrease in infarct size. Multivariate statistical methods such as Principal Component Analysis (PCA), and Discriminant Analysis (DA) were used for the discrimination of samples. The use of ANOVA variable preselection prior to PCA was advantageous in producing adequate models. PCA could classify the Control group in three clusters according to the condition of the heart (baseline-ischemia-reperfusion) while in the IpC groups no classification was evident. PCA discrimination upon treatment with melatonin and C6458 provided further evidence of their effect on the metabolic profile. The supervised DA resulted in fine discrimination between the different subgroups. Plasma NMR spectra in combination with pattern recognition techniques proved to be an efficient and simple method to depict the metabolic changes produced upon ischemia-reperfusion of the myocardium.

Acetates↗
PubMed1996

Assessing the stages of pain processing: a multivariate analytical approach.

A four-stage model of pain processing was proposed, consisting of pain sensation intensity, pain unpleasantness (stage 1 affect), suffering (stage 2 affect), and pain behavior. We studied 506 chronic pain patients (230 male and 276 female) using a multivariate statistical technique (LISREL) in order to demonstrate the structural relationship among multiple indicators of pain processing; and to characterize these stages in terms of their interactions. A strong relationship was revealed between the majority of the underlying indicators of each pain processing stage. A linear stage sequence best fitted the relationship between the four stages. Successive stages did not have recursive effects on earlier pain components. A confirmatory LISREL analysis was conducted with an additional sample of 502 chronic pain patients. In this replication analysis the structural equation model consisted of pain intensity, unpleasantness (stage 1 affect), emotional suffering (stage 2 affect), and pain behavior. This study extends the validation of these pain dimensions, as well as the validity of the measure(s) of each separate stage.

Adolescent↗
PubMed1998

Analysis of factors associated with long-term (five or more years) cure in patients undergoing operation for Zollinger-Ellison syndrome.

BACKGROUND: Only 30% to 40% of patients with Zollinger-Ellison syndrome (ZES) undergoing operation with curative intent have biochemical cures. The purpose of this analysis was to identify perioperative factors associated with long-term (> or = 5 years) biochemical cures. METHODS: From December 1981 to September 1997, 128 patients with potentially curable ZES underwent 152 abdominal explorations with resection of all identifiable disease. Of these, 31 outcomes were identified with documented cures at > or = 5 years from operation and were compared with outcomes of 110 patients who were not cured. Univariate and multivariate statistical analyses were performed. RESULTS: The results of a normal immediate postoperative fasting serum gastrin and secretin stimulation test were significantly and independently correlated with 5-year cure (P2 = .005 and .0099, respectively). A diagnosis of multiple endocrine neoplasia type 1 was significantly inversely correlated with cure on univariate analysis (P2 = .027). Gender, age, duration of symptoms, results of diagnostic tests, or results of imaging studies did not correlate with outcome. CONCLUSIONS: All patients with sporadic potentially curable ZES should undergo exploration because outcome is not associated with preoperative tests. Only 5% of patients with ZES and multiple endocrine neoplasia type 1 were cured at 5 years. A normal fasting serum gastrin or secretin stimulation value value immediately postoperatively provides important prognostic information.

Female↗
PubMed2006

Cortisol levels are positively associated with pup-feeding rates in male meerkats.

In societies of cooperative vertebrates, individual differences in contributions to offspring care are commonly substantial. Recent attempts to explain the causes of this variation have focused on correlations between contributions to care and the protein hormone prolactin, or the steroid hormone testosterone. However, such studies have seldom considered the importance of other hormones or controlled for non-hormonal factors that are correlative with both individual hormone levels and contributions to care. Using multivariate statistics, we show that hormone levels explain significant variation in contributions to pup-feeding by male meerkats, even after controlling for non-hormonal effects. However, long-term contributions to pup provisioning were significantly and positively correlated with plasma levels of cortisol rather than prolactin, while plasma levels of testosterone were not related to individual patterns of pup-feeding. Furthermore, a playback experiment that used pup begging calls to increase the feeding rates of male helpers gave rise to parallel increases in plasma cortisol levels, whilst prolactin and testosterone levels remained unchanged. Our findings confirm that hormones can explain significant amounts of variation in contributions to offspring feeding, and that cortisol, not prolactin, is the hormone most strongly associated with pup-feeding in cooperative male meerkats.

Animals↗
PubMed1997

The effect of universal coverage on health expenditures for the uninsured.

OBJECTIVES: Universal coverage will trigger an increase in health-care spending, because the uninsured will use more services after they are insured. The effect of insurance status on expenditures is estimated here from a multivariate statistical model. METHODS: The model is estimated with data from the 1987 National Medical Expenditure Survey, aged to 1994 using population projections from the US Bureau of the Census and expenditure projections from the Health Care Financing Administration. RESULTS: Expenditures for the full-year uninsured increase by approximately $700 per person in 1994 as a result of universal coverage. Nearly half of the increase is because of a substantial increase in the likelihood of hospitalization. CONCLUSIONS: If the uninsured are enrolled in plans similar to those offered by employers currently, personal health-care spending increases by approximately $20 billion in 1994. There are other costs associated with universal coverage that are not included in this figure.

Adolescent↗
PubMed2000

Exercise capacity in chronic fatigue syndrome.

BACKGROUND: Patients with chronic fatigue syndrome (CFS) suffer from various symptoms, including debilitating fatigue, muscle pain, and muscle weakness. Patients with CFS can experience marked functional impairment. In this study, we evaluated the exercise capacity in a large cohort of female patients with CFS. METHODS: Patients with CFS and matched sedentary control subjects performed a maximal test with graded increase on a bicycle ergometer. Gas exchange ratio was continuously measured. In a second stage, we examined only those persons who achieved a maximal effort as defined by 2 end points: a respiratory quotient of at least 1.0 and an age-predicted target heart rate of at least 85%. Data were assessed using univariate and multivariate statistical methods. RESULTS: The resting heart rate of the patient group was higher, but the maximal heart rate at exhaustion was lower, relative to the control subjects. The maximal workload and maximal oxygen uptake attained by the patients with CFS were almost half those achieved by the control subjects. Analyzing only those persons who performed a maximal exercise test, similar findings were observed. CONCLUSIONS: When compared with healthy sedentary women, female patients with CFS show a significantly decreased exercise capacity. This could affect their physical abilities to a moderate or severe extent. Reaching the age-predicted target heart rate seemed to be a limiting factor of the patients with CFS in achieving maximal effort, which could be due to autonomic disturbances. Arch Intern Med. 2000;160:3270-3277.

Adult↗
PubMed2004

Prediction of ozone concentration in ambient air using multivariate methods.

Multivariate statistical methods including pattern recognition (Principal Component Analysis--PCA) and modeling (Multiple Linear Regression--MLR, Partial Least Squares--PLS, as well as Principal Component Regression--PCR) methods were carried out to evaluate the state of ambient air in Miskolc (second largest city in Hungary). Samples were taken from near the ground at a place with an extremely heavy traffic. Although PCA is not able to determine the significance of variables, it can uncover their similarities and classify the cases. PCA revealed that it is worth to separate day and night data because different factors influence the ozone concentrations during all day. Ozone concentration was modeled by MLR and PCR with the same efficiency if the conditions of meteorological parameters were not changed (i.e. morning and afternoon). Without night data, PCR and PLS suggest that the main process is not a photochemical but a chemical one.

Air↗
PubMed2004

Analysis of factors contributing to improved outcome for carotid endarterectomy.

Since carotid endarterectomy was revitalized following the North American Symptomatic Carotid Endarterectomy Trial and Asymptomatic Carotid Atherosclerosis Study, results have improved. However, types of carotid endarterectomy, indications, risk factors, surgical factors, techniques, and other treatment modalities may be associated with outcomes of carotid endarterectomy. The purpose of this study was to identify those factors in a broad-based carotid endarterectomy patient. This study involved review of the data from 3,644 patients undergoing carotid endarterectomy in New York State hospitals. A multivariate statistical model was used to identify significant patient risk factors to examine the association of the process of care and surgical factors, including surgical specialty for outcome of carotid endarterectomy. In-hospital death and stroke rate overall was 1.84%. After adjustment for patient risk factors, specific processes of care, such as eversion endarterectomy, protamine, heparin, or shunt, were associated with lower adverse outcomes relative to patients undergoing carotid endarterectomy without these processes. Similarly, patients undergoing carotid endarterectomy by vascular surgeons had lower adverse outcomes compared to neurosurgeons and general surgeons. This retrospective review showed that processes of care and surgical specialty were significant factors that contributed to outcomes following carotid endarterectomy.

Age Factors↗
PubMed2004

Genetic changes of the E-cadherin and APC tumour suppressor genes in clear cell renal cell carcinoma.

AIMS: The roles of tumour suppressor genes: adenomatous polyposis coli (APC) and E-cadherin (CDH1) were investigated in clear cell renal cell carcinoma. METHODS: Forty-five human clear cell renal cell carcinomas were tested for APC gene instability by polymerase chain reaction/loss of heterozygosity using the restriction fragment length polymorphism method. E-cadherin gene was analysed by PCR amplification of tetranucleotide marker (D16S752) and the alleles were visualised by PAGE/silver staining. RESULTS: The overall proportion of loss of heterozygosity of the APC gene was 37.5% (9/24). D16S752 marker linked to E-cadherin gene (informativeness 91%) revealed three samples with loss of heterozygosity (7.5%). Interestingly, replication error phenotype was detected in 9.1% of clear cell renal cell carcinoma samples. Multivariate statistical analysis of samples informative for both APC and E-cadherin genes showed that, in this data set, loss of heterozygosity of the APC gene is correlated with advanced age and more severe TNM stages. Genetic changes of the E-cadherin gene, on the other hand, appear to be correlated with younger age groups and less severe TNM stages. CONCLUSIONS: Our results suggest that alterations, both in APC and E-cadherin genes, are involved in the evolution and progression of clear cell renal cell carcinoma. Microsatellite genetic instability of the E-cadherin gene indicates that another cellular mechanism, mismatch repair, may also be targeted in this malignancy.

Adenocarcinoma, Clear Cell↗
PubMed2004

Impact of self-assessed hearing loss on a spouse: a longitudinal analysis of couples.

OBJECTIVES: Hearing loss is increasingly common among older persons and is negatively associated with health and well-being. Its impact on spouses, however, is poorly researched. This study analyzed the relationship between a spouse's self-assessed hearing loss and his or her partner's physical, psychological, and social well-being 5 years later. METHODS: Subjects were 418 older married couples from the Alameda County Study. Hearing loss and adjustment variables were assessed in 1994 and outcomes in 1999. Longitudinal analyses included multivariate statistical models using generalized estimating equations to adjust for paired data and partners' hearing loss, age, gender, chronic conditions, and financial problems. RESULTS: Spouse hearing loss increased the likelihood of subsequent poorer physical, psychological, and social well-being in partners. The negative impact of husbands' hearing loss on wives' well-being appears stronger than the reverse. DISCUSSION: Findings suggest that early diagnosis and treatment of hearing loss constitute important clinical strategies to enhance the well-being of both hearing-impaired individuals and their spouses and support policy change to cover hearing devices by insurance. Further research incorporating theoretical perspectives from communication theory and qualitative methodology would enhance understanding of how hearing loss impacts older couples and support refinement of interventions to promote quality of life.

Adaptation, Psychological↗
PubMed1993

Solid organ transplantation: results and implications of acyclovir use in liver transplants.

CMV infection is a major cause of morbidity and mortality following liver transplantation (LT). A prospective study of 218 LT recipients showed that 55% of patients developed CMV infection during the 1st year post-transplantation. Symptomatic CMV infection developed in 25% of all patients, being a major cause of death (21% of all deaths). Of 62 episodes of documented organ invasion, liver was the major site (38 episodes), followed by lung (20), gastrointestinal (4), and retina (4). The main patient group at risk (according to CMV serology of the recipient [(R)/donor(D)]) was the R-/D+: 77% of patients developed CMV infection, all of them with symptoms. The lowest group at risk was the R-/D-: 13% of patients developed CMV infection, half of whom developed symptoms. Time-dependent multivariate statistical analysis of risk factors indicated that the R-/D+ group was the main risk factor for CMV infection (P < .02) and symptomatic infection (P < .0001). To decrease the incidence and severity of CMV infection following LT, a randomized study is ongoing to evaluate the efficacy of ganciclovir (5 mg/kg/IV/q 12 hours for the first 14 days post-LT) followed by acyclovir (800 mg/po/qid for 14 weeks) GCV + ACV (group I), versus acyclovir (same dose for 16 weeks, starting immediately post-LT) ACV (group II). These treatment groups are compared to matched historical controls (C). Preliminary analysis of 83 LT recipients indicates that in group I the median date for the first evidence of CMV infection is delayed (82 days) as compared to group II and C (41 and 33 days, respectively) (P = .004).(ABSTRACT TRUNCATED AT 250 WORDS)

Acyclovir↗
PubMed2005

Studies on codon usage in Thermoplasma acidophilum and its possible implications on the occurrences of lateral gene transfer.

Codon usage studies have been carried out on the coding sequences of Thermoplasma acidophilum, which is an archaeon and grows at very low pH and high temperature. Overall codon usage data analysis indicates that all the four bases are almost equifrequent at the third position of codons, which is expected (since genomic GC % of this genome is about 46%). However, multivariate statistical analysis indicates that there are two major trends in the codon usage variation among the genes in this organism. In the first major trend it is observed that genes having G and C ending codons are clustered at one end while, A and T ending ones are clustered at the other end. We have also found a significant positive correlation between the expressivities of genes and GC contents at the synonymous third codon positions. In the second major trend, it is seen that the genes are clustered into three distinct parts. A comparative analyses of codon usage data of T. acidophilum and Sulfolobus solfataricus reveals that one of the three clusters of genes of T. acidophilum is very similar to a considerable number of S. solfataricus genes, suggesting possible occurrences of lateral gene transfer between these two microorganisms as reported by earlier workers.

Codon↗
PubMed1996

Prognostic factors for patients with advanced non-small cell lung cancer: univariate and multivariate analyses including recursive partitioning and amalgamation.

In an attempt to determine the prognostic significance of pretreatment factors for patients with advanced non-small cell lung cancer (NSCLC), 24 pretreatment clinical variables were analyzed for 185 patients with NSCLC who underwent chemotherapy and/or radiotherapy between 1985 and 1994. Following univariate analysis, we applied two multivariate statistical techniques. In a Cox regression mode, independently significant factors influencing patient survival included performance status (PS), disease stage, hemoglobin level, and serum calcium level. Recursive partitioning and amalgamation (RPA) resulted in three distinct prognostic subgroups based on PS, stage, weight loss, and hemoglobin level. The best survival was observed for patients with a good PS and Stage III disease who had a hemoglobin level > 11 g/dl. The worst survival was observed for patients with a poor PS and presence of weight loss irrespective of stage. All other patients had an intermediate prognosis. Median survival times were 95.1 weeks, 17.1 weeks and 39.3 weeks, respectively (P < 0.00005). The results of our analyses show that three important prognostic subgroups could readily be discerned using RPA.

Adult↗