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Results for “Statistics, Nonparametric”

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PubMed1988

Is chymotrypsin output a better diagnostic index than the measurement of chymotrypsin in random stool?

This study compares the diagnostic utility of fecal chymotrypsin (CT) output in timed stool collections and random stools using a new photometric enzyme assay. The CT output (mean +/- SD, U/24 h) was 1,487 +/- 1,980 in 127 children with normal fat absorption and negative sweat-chloride test (mean age 45 months), and 1,804 +/- 1,452 in 27 cases with fat malabsorption due to nonpancreatic disease (mean age 41 months). 66 cases of cystic fibrosis (CF) were examined (mean age 119 months). Stool output in 19 newly diagnosed patients before therapy was 85 +/- 94, in 42 patients receiving enzyme replacement therapy was 3,462 +/- 2,841, and in 5 patients with pancreatic sufficiency 1,754 +/- 1,482. Using nonparametric statistics, 120 U/24 h was defined as the lower limit of the 95-percentile for stool CT output. Only 5 of the 127 patients with normal fat absorption had output below that limit. None of the patients with nonpancreatic malabsorption and only 1 treated CF patient had lower values. Sixteen of the newly diagnosed CF patients had stool CT less than 120 U/24 h. The sensitivity of the test is therefore 84% and its specificity 97% at this decision threshold. However, no diagnostic advantage is gained from measuring CT output in timed stool collections as compared to random stools.

Age Factors↗

PubMed1999

Linkage of a candidate gene locus to familial combined hyperlipidemia: lecithin:cholesterol acyltransferase on 16q.

Familial combined hyperlipidemia (FCHL) is a common lipid disorder characterized by elevated levels of plasma cholesterol and triglycerides that is present in 10% to 20% of patients with premature coronary artery disease. To study the pathophysiological basis and genetics of FCHL, we previously reported recruitment of 18 large families. We now report linkage studies of 14 candidate genes selected for their potential involvement in the aspects of lipid and lipoprotein metabolism that are altered in FCHL. We used highly polymorphic markers linked to the candidate genes, and these markers were analyzed using several complementary, nonparametric statistical allele-sharing linkage methodologies. This current sample has been extended over the one in which we identified an association with the apolipoprotein (apo) AI-CIII-AIV gene cluster. We observed evidence for linkage of this region and FCHL (P<0.001), providing additional support for its involvement in FCHL. We also identified a new locus showing significant evidence of linkage to the disorder: the lecithin:cholesterol acyltransferase (LCAT) locus (P<0.0006) on chromosome 16. In addition, analysis of the manganese superoxide dismutase locus on chromosome 6 revealed a suggestive linkage result in this sample (P<0.006). Quantitative traits related to FCHL also provided some evidence of linkage to these regions. No evidence of linkage to the lipoprotein lipase gene, the microsomal triglyceride transfer protein gene, or several other genes involved in lipid metabolism was observed. The data suggest that the lecithin:cholesterol acyltransferase and apolipoprotein AI-CIII-AIV loci may act as modifying genes contributing to the expression of FCHL.

Adult↗

PubMed1999

Intravenous immunoglobulin reduces anti-HLA alloreactivity and shortens waiting time to cardiac transplantation in highly sensitized left ventricular assist device recipients.

BACKGROUND: Recipients of left ventricular assist devices (LVADs) develop prominent B-cell hyperreactivity. We investigated the influence of anti-HLA antibodies on waiting time to cardiac transplantation in LVAD recipients and compared the effects of 2 immunomodulatory regimens on anti-HLA serum reactivity. METHODS AND RESULTS: Fifty-five previously nonsensitized LVAD recipients of a TCI device implanted between 1990 and 1996 were studied. Patients with anti-HLA antibodies received monthly courses of either intravenous immunoglobulin (IVIg) or plasmapheresis, in conjunction with cyclophosphamide. The effects of these regimens on anti-HLA alloreactivity and waiting time to transplantation were then determined by Kaplan-Meier log-rank statistics, nonparametric Wilcoxon rank-sum test, and Student's t test. Prolongation in transplant waiting time was related to serum IgG anti-HLA class I alloreactivity. Infusion of IVIg (2 g/kg) caused a mean reduction of 33% in anti-HLA class I alloreactivity within 1 week. Waiting time to transplantation was significantly reduced by IVIg therapy and subsequently approximated that in nonsensitized patients. Side effects of IVIg (2 g/kg) were minimal and related primarily to immune complex disease. Although plasmapheresis caused a similar reduction in alloreactivity to IVIg, this effect was achieved after longer treatment. Moreover, plasmapheresis was associated with an unacceptably high frequency of infectious complications. In patients resistant to low-dose (2 g/kg) IVIg therapy, high-dose (3 g/kg) IVIg was effective in reducing alloreactivity but was associated with a high incidence of reversible renal insufficiency. CONCLUSIONS: These results indicate that IVIg is an effective and safe modality for sensitized recipients awaiting cardiac transplantation, reducing serum anti-HLA alloreactivity and shortening the duration to transplantation. The therapeutic and safety profile of IVIg would appear to be superior to plasmapheresis.

Graft Rejection↗

PubMed1995

Plasma elastase levels and the development of the adult respiratory distress syndrome.

Inflammatory cells, particularly neutrophil granulocytes, have been implicated in the pathogenesis of the adult respiratory distress syndrome (ARDS). In this study, we investigated whether a relationship exists between neutrophil elastase in the plasma of multiple-trauma patients on initial hospital presentation and the subsequent development of lung injury and ARDS. Sixty-one multiple-trauma patients were enrolled prospectively. Neutrophil elastase was measured by a specific radioimmunoassay, and analysis was performed by nonparametric statistical methods. A highly significantly elevated plasma elastase level was found in patients who progressed to ARDS (median 217 ng/ml, range 127 to 480) (n = 8) compared with those who did not (median 117 ng/ml, range 21.4 to 685) (n = 53) (p = 0.009). Significant correlation was found between initial elastase values and subsequent requirement for mechanical ventilation (p = 0.01), lowest arterial oxygen saturation/oxygen supplementation recorded (p = 0.003), and organ failure score (p = 0.006). This study shows that within minutes of the initiating trauma event, there is evidence of enhanced neutrophil degranulation as manifested by elevated levels of immunoreactive neutrophil elastase in the peripheral blood. The level of this enzyme correlates with the degree of subsequent lung injury and ARDS. These findings reinforce the importance of neutrophils and their secretory products in early ARDS disease pathogenesis.

Adolescent↗

PubMed2003

Expression of the lipogenic enzyme fatty acid synthase (FAS) in retinoblastoma and its correlation with tumor aggressiveness.

PURPOSE: Fatty acid synthase (FAS) performs the anabolic conversion of dietary carbohydrate or protein to fatty acids. Many common human cancers express high levels of FAS, and its differential expression between normal and neoplastic tissues has led to the consideration of FAS as a target for anticancer therapy. To investigate the potential of targeting FAS in the treatment of retinoblastoma, we first determined whether FAS was activated in this human tumor. Moreover, correlation of FAS expression with tumor aggressiveness was determined. METHODS: FAS reactivity was evaluated by immunohistochemistry in 66 retinoblastoma specimens from 65 patients. Degree of tumor differentiation, choroid invasion, optic nerve infiltration, mitotic rate, and necrosis extension were estimated. FAS expression was correlated with all these tumor characteristics by means of parametric and nonparametric statistical analyses. RESULTS: Eighty-two percent of tumors were FAS positive. Stronger FAS expression correlated with more advanced choroid (P < 0.001) and optic nerve (P = 0.016) invasion, high mitotic index (P < 0.001), and less differentiated histology (P = 0.047). Correlation with extension of necrosis was not statistically significant. Unaffected retina was negative. CONCLUSIONS: The data suggest that expression of FAS and fatty acid synthesis support an essential functional aspect of retinoblastoma cells, perhaps cell growth or survival. FAS activation may serve as a novel target for systemic and local antineoplastic therapy and, because it increases with tumor aggressiveness, its inhibition could represent an alternative treatment strategy in advanced and resistant retinoblastomas.

Child↗

PubMed2003

Multifocal electroretinographic features of central retinal vein occlusion.

PURPOSE: To determine the features of wide-field multifocal electroretinography (WF-mfERG) recorded in patients with central retinal vein occlusion (CRVO) and to compare WF-mfERG responses of the affected and fellow eyes. In addition, WF-mfERG responses were also compared by using standard electroretinography (ERG). METHODS: WF-mfERG and ERG responses were recorded from both eyes of 56 patients with CRVO. The WF-mfERG responses, obtained using a custom-built system were grouped into central and peripheral rings. The P1 amplitudes, and P1 and N1 implicit times were grouped and averaged within both rings. Nonparametric statistical analysis was used to compare the ERG results from the affected and fellow eyes. The results were also compared with normative data (5% to 95% confidence limits). RESULTS: CRVO markedly affected all the parameters of the WF-mfERG. In the affected eyes, 98% of the central and 91% of the peripheral P1 implicit times fell outside the normal range, as opposed to 35% of the 30-Hz flicker implicit times. The WF-mfERG responses obtained from eyes with CRVO were significantly different (P<0.01) from those derived from the fellow eye. The central and peripheral P1 implicit times were also abnormal in 59.2% and 46.9% of the fellow eyes, respectively. CONCLUSIONS: WF-mfERG is more susceptible than the standard ERG to changes in the nonlinear dynamics of the eye due to the multiple frequencies of stimulation used to record WF-mfERG responses. WF-mfERG could be a sensitive indicator of the underlying disease affecting the retina in eyes with CRVO and may have a role in the clinical setting.

Adult↗

PubMed1994

Treatment of consecutive episodes of major depression in the elderly.

OBJECTIVE: The purpose of this study was to determine treatment outcome in elderly patients with consecutively treated episodes of recurrent unipolar major depression. METHOD: Subjects were 32 "young" elderly patients with recurrent unipolar depression (mean age = 66.8 years, SD = 5.1) and with two consecutively treated episodes of major depression. Both index and subsequent episodes of major depression were treated in open trial with combined nortriptyline and interpersonal psychotherapy. Rates of remission in index and subsequent episodes were compared by using nonparametric statistics and survival analysis with proportional hazards modeling. RESULTS: Of 30 patients who completed treatment of the subsequent episode, 27 (90%) achieved stable remission of symptoms in both consecutively treated episodes, whereas three patients (10%) did not. Twenty-two (81%) of 27 patients who responded to treatment had a shorter time to remission in treatment of the subsequent episode than in the index episode. Survival analysis with proportional hazards modeling detected a significant difference in time to remission of the index and subsequent episodes (32 paired observations). CONCLUSIONS: In this research study group, recurrent episodes of unipolar major depression in the young elderly were successfully treated to remission in over 80% of patients by using combined pharmacotherapy and psychotherapy similar to that employed in treatment of the index episode. Remission rate and time to remission in consecutively treated episodes were comparable to those in a group of midlife patients with recurrent depression reported by Kupfer et al. in 1989. Thus, recurrent depressive disorder appears to be as treatable in the young elderly as it is in midlife patients.

Age Factors↗

PubMed1995

Demographic and clinical comparison of obsessional followers and offenders with mental disorders.

OBJECTIVE: The purpose of this study was to compare certain demographic and clinical variables in a group of obsessional followers and in a group of offenders with mental disorders. METHOD: A static group design comprised of a nonrandom group of convenience and a randomly selected comparison group was used. Twenty obsessional followers in custody and 30 offenders with mental disorders in custody were evaluated by psychiatrists and psychologists for court-ordered reasons during their criminal proceedings. Both groups were evaluated during the same period, in the same court diagnostic clinic, and for the same psycholegal reasons. The group of obsessional followers was measured on demographic, clinical, and victim variables. Inferential comparisons that used nonparametric statistics were done between groups on selected demographic and clinical variables. RESULTS: The obsessional followers were significantly older, more intelligent, and better educated than the offenders. There were no significant differences in DSM-III-R axis I diagnoses. Axis II diagnoses showed significant differences, with the obsessional followers more likely to have a personality disorder other than antisocial personality disorder and less likely to have antisocial personality disorder. CONCLUSIONS: The likelihood of obsessional followers having a nonantisocial axis II personality disorder (related to attachment pathology) distinguishes them from offenders with mental disorders in general. They are also likely to be older, smarter, and better educated, consistent with their resourcefulness and manipulativeness. Idiographic aspects of the obsessional followers further illuminate their psychological defenses and object relations.

Adolescent↗

PubMed2003

Are gender differences important for the clinical effects of antidepressants?

OBJECTIVE: Gender differences in antidepressant treatment response, side effects, dropout rates, and plasma concentrations were examined in patients with major and predominantly melancholic depression. METHOD: The study included a subgroup of 292 inpatients (96 men, 196 women) from three Danish double-blind, randomized, controlled trials. All patients completed a 5-week treatment period and fulfilled the DSM-III or DSM-III-R criteria for major depression. Clomipramine (150 mg/day) was the reference treatment, and comparable treatments were citalopram (40 mg/day), paroxetine (30 mg/day), and moclobemide (400 mg/day). Assessments were performed by using the 17-item Hamilton Depression Rating Scale and the Udvalg for Kliniske Undersøgelser Side Effect Rating Scale. In a subgroup of 110 patients, weekly measurements of clomipramine plasma concentrations were obtained. Nonparametric statistical tests and multiple linear and logistic regression models were used for statistical evaluations. RESULTS: Both genders had similar remission rates (Hamilton depression scale score <8) when treated with clomipramine and had significantly higher remission rates with clomipramine than with the comparable treatments. The plasma concentrations of clomipramine were significantly higher for female than for male patients. No gender differences were found in posttreatment Hamilton depression scale scores, nor did the therapeutic effects of treatment depend on gender. Rates of dropout and side effects were similar for men and women. No relationship between plasma concentrations, gender, and therapeutic outcome was found. CONCLUSIONS: In a group of patients with major and predominantly melancholic depression, differentiation according to gender was not important in treatment with common antidepressants. Women appeared to have higher plasma concentrations of tricyclic antidepressants than men. The consequences of this difference for clinical effects are unclear. Gender-specific recommendations for dosing of tricyclic antidepressants may be considered.

Antidepressive Agents↗

PubMed2002

New-generation pulsed carbon dioxide laser: comparative effects on vocal fold wound healing.

We investigated wound healing of vocal fold mucosal excisions using a canine model, comparing cold steel, the continuous wave (CW) carbon dioxide (CO2) laser, and a new, microsecond-pulsed CO2 laser. The thermal injury to the surrounding normal tissues produced by the laser increases the risk for scar formation and poor functional voice outcome. This injury may be reduced with a pulsed CO2 laser. Acute, 2-week, and 6-week studies of 15 dogs were made with blinded observers and nonparametric statistical analyses. Histologic comparison showed less thermal injury and scar formation in the vocal folds treated with the pulsed CO2 laser than with the CW CO2 laser. Functional outcomes as studied with laryngeal videostroboscopy revealed better vibratory characteristics with the pulsed CO2 laser as compared with the CW CO2 laser. No differences were seen on these measures between the pulsed laser and cold techniques. Pulsed CO2 lasers may offer the ease of laser laryngology and the superior wound healing of cold steel.

Animals↗

PubMedDate not supplied

Syringe disposal practices and gender differences.

PURPOSE: The purpose of this study was to describe syringe disposal practices of individuals with diabetes who take insulin and to investigate the attitude toward and effect of previous information on proper syringe disposal. METHODS: Adult men and women who injected insulin were recruited from an endocrinology practice and given 2 questionnaires concerning syringe disposal practices and attitude toward proper syringe disposal. Completed questionnaires were returned by mail to the investigator. Nonparametric statistical procedures were used to analyze the data. RESULTS: Men with higher income tended to use the trash for syringe disposal more often than lower income men, and older women exhibited a higher positive attitude score than younger women. A positive attitude significantly correlated with the likelihood of proper syringe disposal, and those who had received previous information were more likely to dispose of syringes properly. Healthcare providers were identified as the main source of information. CONCLUSIONS: Diabetes educators can improve the syringe disposal practices of their patients through education at each office visit. Knowing more about the environmental and social problems that may ensue from improper syringe disposal may influence patients to practice better disposal methods.

Adult↗

PubMedDate not supplied

Greatest fears of type 1 and type 2 patients about having diabetes: implications for diabetes educators.

This exploratory study was undertaken to describe the differences in the greatest fears about having diabetes between type 1 and type 2 patients. Frequency distributions, measures of central tendency, and nonparametric statistics were employed to examine the traits of the sample and to make comparisons between type 1 and type 2 patients. Content analysis was used to describe and analyze the subjects' responses to the question, What is your greatest fear about having diabetes? Subjects' answers to this question were categorized and scored as representing fear of either a long-term or acute complication based on the clinical judgment of the authors. Results revealed that both type 1 and type 2 patients were likely to have given responses that were suggestive of fear of long-term complications. The major fears concerned amputation, cardiovascular disease, nephropathy, neuropathy, retinopathy, and stroke. The findings of the present investigation suggest that diabetes educators may need to address patients' fears of long-term complications directly and effectively. Several areas of research that grew out of this exploratory study were recommended for future consideration.

Adult↗

PubMed1997

Description of a self-care instrument for elders.

The psychometric properties of the self-care component of the Abilities Assessment Instrument were studied with elderly women. Thirty of the participants were cognitively impaired and 20 participants were not. Nonparametric statistics were used as the data were not normally distributed. Using the Spearman rank order correlation coefficient, test-retest reliability was rs = .79; p < .01 (n = 10) and interrater agreement was rs = .97; p < .01 (n = 9). Cronbach's alpha was .97. Between two content experts, the index of content validity was .89. Concurrent validity was assessed by comparing the self-care scores with the MMSE scores (rs = .91; p < .01). To establish construct validity, the self-care scores of those with dementia were shown to be statistically different from those who did not have dementia (Mann-Whitney U = 85). This study provided evidence for the reliability and validity of this self-care instrument.

Aged↗

PubMedDate not supplied

Power and sample size in cost-effectiveness analysis.

For resource allocation under a constrained budget, optimal decision rules for mutually exclusive programs require that the treatment with the highest incremental cost-effectiveness ratio (ICER) below a willingness-to-pay (WTP) criterion be funded. This is equivalent to determining the treatment with the smallest net health cost. The designer of a cost-effectiveness study needs to select a sample size so that the power to reject the null hypothesis, the equality of the net health costs of two treatments, is high. A recently published formula derived under normal distribution theory overstates sample-size requirements. Using net health costs, the authors present simple methods for power analysis based on conventional normal and on nonparametric statistical theory.

Bias↗

PubMed2002

Acute psychiatric inpatient care for people with a dual diagnosis: patient profiles and lengths of stay.

OBJECTIVE: This study describes characteristics of psychiatry inpatients with developmental disabilities (DD) and their admissions to psychiatry wards in 2 acute care hospitals. It also compares differences in lengths of stay between admissions of this group with a comparison sample of inpatient admissions without DD. METHOD: A retrospective chart review was conducted on all individuals with DD who were psychiatric inpatients at 2 Kingston, Ontario, general hospitals, within a 4-year period (1994 to 1998). A comparison sample of admissions of patients without DD was chosen. Frequency tables were used to describe the inpatients with DD and to describe the 2 samples of admissions. Nonparametric statistics were used to compare the median length of stay between the 2 samples. Associations between length of stay and other covariates were explored within the sample of patient admissions with DD. RESULTS: The 62 individuals with DD had 101 admissions over the study period. Suicidal ideation was the most common admission reason (46%), and mood disorder was the most common discharge diagnosis (29%). The median length of stay for patients with DD was 8 days, which did not differ meaningfully from the comparison sample. Variables that were significantly associated with length of stay among individuals with DD included sex, referral source, and diagnosis. CONCLUSION: When individuals with DD are psychiatric inpatients, their length of stay is affected by some factors that have been identified in previous studies not specific to DD (for example, referral source and diagnosis). Our finding that male patients with DD have longer lengths of stay than do female patients in the same sample has not been reported in previous research.

Adolescent↗

PubMed2001

Stormwater run-off and pollutant transport related to the activities carried out in a modern waste management park.

Stormwater run-off from twelve different areas and roads has been characterized in a modern waste disposal site, where several waste management activities are carried out. Using nonparametric statistics, medians and confidence intervals of the medians, 22 stormwater quality parameters were calculated. Suspended solids, chemical oxygen demand, biochemical oxygen demand, total nitrogen and total phosphorus, as well as run-off from several areas, showed measured values above standard limits for discharge into recipient waters--even higher than those of leachate from covered landfill cells. Of the heavy metals analyzed, copper, zinc and nickel were the most prevalent, being detected in every sample. Higher concentrations of metals such as zinc, nickel, cobalt, iron and cadmium were found in run-off from composting areas, compared to areas containing stored and exposed scrap metal. This suggests that factors other than the total amount of exposed material affect the concentration of metals in run-off, such as binding to organic compounds and hydrological transport efficiency. The pollutants transported by stormwater represent a significant environmental threat, comparable to leachate. Careful design, monitoring and maintenance of stormwater run-off drainage systems and infiltration elements are needed if infiltration is to be used as an on-site treatment strategy.

Environmental Monitoring↗

PubMed1992

Aerosolized pentamidine and Pneumocystis carinii pneumonia: patient compliance and outcomes.

OBJECTIVE: The study objectives were to compare compliance between every-two-week and every-four-week aerosolized pentamidine regimens, and to determine if patients who were more compliant with the use of aerosolized pentamidine were at decreased risk for developing Pneumocystis carinii pneumonia (PCP). DESIGN: Nonrandomized observational study of patients receiving aerosolized pentamidine for PCP prophylaxis using the hospital pharmacy computer system to document aerosolized pentamidine use and compliance, and the Patient Administration Division's computer to document cases of PCP. SETTING: Tertiary care, US Army medical center. PATIENTS: All patients who were prescribed aerosolized pentamidine (60 mg every two weeks, 300 mg every four weeks, or both) over a 3.5-year period. MAIN OUTCOME MEASURES: Mean percent compliance was determined and compared between every-two-week and every-four-week regimens. The relationship between compliance and cases of PCP as determined using nonparametric statistics. RESULTS: Patients (n = 146) who were prescribed aerosolized pentamidine 60 mg every two weeks were more compliant (p = 0.006) than those prescribed 300 mg every four weeks. In addition, those patients who initially received the 60-mg regimen and were switched to the 300-mg regimen were more compliant when taking the 60-mg dose (p = 0.027). There was no association between compliance with either regimen and cases of PCP. Compliance generally was poor with both regimens. CONCLUSIONS: Patients on every-two-week regimens of aerosolized pentamidine were more compliant than those on every-four-week regimens. However, regardless of compliance, some patients failed aerosolized pentamidine over the 3.5-year period. Other agents that lend themselves to compliance may be more appropriate for PCP prophylaxis than aerosolized pentamidine.

Administration, Inhalation↗

PubMed2005

Identification of a small molecule that induces mitotic arrest using a simplified high-content screening assay and data analysis method.

High-content screening has emerged as a new and powerful technique for identifying small-molecule modulators of mammalian cell biology. The authors describe the development and execution of a high-content screen to identify small molecules that induce mitotic arrest in mammalian cancer cells. Many widely used chemotherapeutics, such as Taxol and vinblastine, induce mitotic arrest, and the creation of new drugs that also induce mitotic arrest may have tremendous therapeutic value. In their screen, the authors employed a simple DNA stain (DAPI) and a sensitive nonparametric statistical test to identify compounds from an internal collection of approximately 13,000 high-quality lead-like small molecules. Subsequent analysis of 1 active compound indicated that it induces mitotic arrest, assessed using a high-content phosphohistone H3 detection assay, and caused cell proliferation defects in multiple cancer cell lines. The active compound, a quinazolinone originating from a natural product-like subset of the screened compounds, is active in cells at approximately 500 nM and appears to act by inhibiting the polymerization of tubulin.

Biological Assay↗