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Results for “multivariate analysis”

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PubMed1999

Multivariate analysis of primitive reflexes in patients with human immunodeficiency virus type-1 infection and neurocognitive dysfunction.

To prove that primitive reflexes are independent markers of symptomatic human immunodeficiency virus type-1 (HIV-1) infection, a case-control study was carried out in a tertiary care, university teaching hospital. Thirty HIV-1-positive symptomatic cases, 30 seropositive asymptomatic controls and 30 HIV-1 seronegative controls consented to participate and were selected consecutively. A single examiner blinded to serostatus administered the Mini-Mental State Exam and a structured neurological exam to each participant. Up to 45% of cases had cognitive impairment. The occurrence of neurologic signs between seropositive cases and seropositive controls was similar, but the number of primitive reflexes was significantly higher in cases (P < 0.001). By multivariate discriminant analysis, all primitive reflexes but two correctly classified 83.3% of all participants (P = 0.0013). The model had a positive predictive value of 97% when motor, mood, and cognitive symptoms were added (P = 0.0001). Primitive reflexes were independent predictors of HIV-1 serostatus, especially for those with cognitive dysfunction. Primitive reflexes should be included in future case definitions of HIV-1-related neurocognitive disorders.

AIDS Dementia Complex↗

PubMed2003

Voltammetry assisted by multivariate analysis as a tool for speciation of metallothioneins: competitive complexation of alpha- and beta-metallothionein domains with cadmium and zinc.

Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) is applied to voltammetric data obtained in the study of competitive complexation of Zn(II) and Cd(II) by alpha- and beta-domains of metallothionein (MT). The application of MCR-ALS allows the estimation of both the voltammograms and the concentration profiles associated with each electrochemical process. The complexity of the voltammograms obtained in titrations of the alpha- or beta-domains of MT with Cd(II) and later Zn(II) (or vice versa) prevents their direct interpretation using traditional electrochemical methods. But when MCR-ALS is applied, voltammograms can be interpreted rather satisfactorily in both qualitative and quantitative terms. MCR-ALS showed the formation of Cd2Znbeta dom and Cd3Znalpha dom complexes when both metals were competitively added. A method based on the combined use of voltammetry and some chemometric techniques is proposed. It can be useful for the metal speciation of environmentally relevant natural ligands.

Cadmium↗

PubMed1998

Umbilical blood flow and neonatal morphometry: a multivariate analysis.

OBJECTIVE: To study the relation between the state of umbilical blood flow and neonatal morphometry. STUDY DESIGN: We have recorded data from 460 pregnant women. Umbilical systolic to diastolic ratio was measured within the 3 days prior to the birth. Weight, height, head and chest circumferences, ponderal and head to chest circumferences ratio were considered for the study. RESULTS: In a univariate analysis, the best correlated variable to S/D ratio was the weight (r=-0.35). However, a forward stepwise multiple regression analysis demonstrated that the best predictors of S/D ratio were height and ponderal index. Small-for-gestational-age fetuses with placental insufficiency (n=20) had a significant more pronounced decrease of weight, height, head circumference and chest circumference than those with normal placental perfusion (n=31). The degree of decrease of ponderal index and HC/TC was similar in both groups. CONCLUSIONS: Umbilical blood flow is one important factor determining newborn morphometry. If only one growth variable is considered, the best correlation with umbilical S/D ratio is found to be the weight. The multivariate regression analysis concluded that the two most influential factors by umbilical blood flow are height and ponderal index and the rest of the morphometric parameters lost their significant correlations when adjusted by these variables. The impairment on neonatal morphometry in small-for-gestational-age fetuses associated to placental insufficiency is more severe than that with normal placental perfusion. However, it does not have a more pronounced decrease of ponderal index than the rest of causes of small-for-gestational-age fetuses.

Adult↗

PubMed1994

Role of hepatitis C and delta viruses in the termination of chronic hepatitis B surface antigen carrier state: a multivariate analysis in a longitudinal follow-up study.

Influences of hepatitis delta (HDV) or C virus (HCV) superinfection on the spontaneous clearance of hepatitis B virus (HBV) surface antigen (HBsAg) were investigated in 992 patients. Patients were infected with HBV alone (group 1), HBV and HDV (group 2), HBV and HCV (group 3), or all three viruses (group 4). They were followed for 6.2 +/- 3.7 years. Thirty-six patients (3.6%) had spontaneous serum HBsAg clearance. There was an increasing linear trend in the annual incidence from 0.43% (group 1) to 0.64% (group 2), 2.08% (group 3), and 2.33% (group 4; P < .0001). Relative risk (RR) of group 3 to 1 was 4.8 (P < .001) and of group 4 to 1 was 5.1 (P < .02). RR was significantly higher in group 3 than 2 (P < .02). By Cox multivariate regression analysis, only HCV superinfection and age at entry were significant influencing factors. Moreover, there was a significant interaction between HCV and age. Patients > 35 years old with HCV had a higher HBsAg clearance rate. Results suggest that HCV is the most important hepatotropic virus that enhances HBsAg clearance in chronic hepatitis B.

Adolescent↗

PubMed2002

A multivariable analysis of factors influencing mucositis after autologous progenitor cell transplantation.

Mucositis is a common and vexing complication of autologous progenitor cell transplantation (ABMT). A modified oral mucositis assessment scale (OMAS) has been found to be a reproducible and effective tool for monitoring mucositis after radiation therapy or chemotherapy. We utilized the modified OMAS scale to study clinical parameters associated with the development of mucositis in 79 patients undergoing ABMT. Median patient age was 52; 61% had non-Hodgkin's lymphoma (NHL), 23% multiple myeloma and 14% Hodgkin's disease. Patients were mobilized with G-CSF alone or the combination of etoposide plus G-CSF. Univariable correlates of worse mucositis were prior radiation therapy (P = 0.004), a diagnosis of NHL (P = 0.014), progenitor cell mobilizing regimen containing etoposide (P = 0.001), and ABMT preparative regimen containing etoposide (P = 0.006). Multivariable regression analysis revealed that NHL diagnosis (P = 0.007), prior radiation therapy (P = 0.001), and etoposide in the mobilizing regimen (P = 0.034) were associated with worse post-transplant mucositis. Worsening mucositis correlated with a longer inpatient length of stay. We conclude that several variables contribute to worsening mucositis during autologous transplantation, including etoposide in the progenitor cell mobilizing regimen.

Etoposide↗

PubMed2002

[Multivariate analysis of factors influencing the effect of radiosynovectomy].

OBJECTIVE: In this prospective study, the time to remission after Radiosynovectomy (RSV) was analyzed and the influence of age, sex, underlying disease, type of joint, and duration of illness on the success rate of RSV was determined. METHODS: A total number of 57 patients with rheumatoid arthritis (n = 33) and arthrosis (n = 21) with a total number of 130 treated joints (36 knee, 66 small and 28 medium-size joints) were monitored using visual analogue scales (VAS) from one week before RSV up to four to six months after RSV. The patients had to answer 3 times daily for pain intensity of the treated joint. The time until remission was determined according to the Kaplan-Meier survivorship function. The influence of the prognosis parameters on outcome of RSV was determined by multivariate discriminant analysis. RESULTS: After six months, the probability of pain relief of more than 20% amounted to 78% and was significantly dependent on the age of the patient (p = 0.02) and the duration of illness (p = 0.05), however not on sex (p = 0.17), underlying disease (p = 0.23), and type of joint (p = 0.69). CONCLUSION: Irrespective of sex, type of joint and underlying disease, a measurable pain relief can be achieved with RSV in 78% of the patients with synovitis, whereby effectiveness is decreasing with increasing age and progress of illness.

Arthritis, Rheumatoid↗

PubMedDate not supplied

[Prognosis and immunomorphological characteristics in rectal cancer: results of a multivariate analysis].

The survival advantage of a pronounced lymphocytic infiltration within and around the primary tumor and some hyperplastic reactions in the regional lymph nodes in specimens of colorectal cancer has been reported in many studies. However, none of these studies allowed the grade of these immunomorphological reactivities to compete with more traditional prognostic variables, using the proportional hazard models. In this study the survival rates of 219 patients who underwent operation for rectal cancer were analyzed statistically according to sex, age, tumor site, type of operation, histology, nuclear grade, p-TNM stage of disease and to the following immunomorphological parameters: lymphocytic infiltration (LI) within and around the primary tumor, paracortical activity (PCA), cortical activity (CA) and sinus histiocytosis (SH) of the regional lymph nodes. The presence of an evident local and regional immune reactivity was significantly related to a less advanced stage of disease and better differentiated tumor. The multivariate survival analysis (Cox model) identified LI, PCA and SH and p-TNM stage as independent prognostic factors. Survival within each stage progressively increased in presence of one or more favourable immunomorphologic features. These results indicate that an adequate prospective evaluation of LI, PCA and SH should improve our ability to assess prognosis in rectal cancer and, therefore, allow a more rational utilization of adjuvant therapy.

Female↗

PubMed2002

Differentiating benign nevi from malignant melanoma using DNA microdensitometry and karyometry and maturation: a zonal comparison, correlation and multivariate analysis.

OBJECTIVE: To evaluate the diagnostic effectiveness of cytometric features of DNA microdensitometry, karyometry (nuclear morphometry) and maturation and their combinations in separating benign nevi from malignant melanomas. STUDY DESIGN: Tumor cells were measured from each of the superficial, middle and deep zones of 81 melanocytic lesions using video image analysis for nuclear DNA content, chromatin compactness, and nuclear size and shape variables. There were 27 banal compound melanocytic nevi, 20 dysplastic compound nevi, 10 Spitz nevi and 24 malignant melanomas (MM). Maturation of cells with depth into the dermis was also studied by comparing cells from superficial to deep zones. RESULTS: MM showed distinct characteristics of DNA microdensitometry, karyometry and maturation as compared to all groups of benign nevi. There were overall close correlations between nuclear DNA content variables and nuclear size parameters in the total group of 81 lesions. However, there were fewer significant correlations between the various indices in the group of melanomas alone. Using multivariate discriminant analysis, up to 97% of the lesions could be correctly separated as benign or malignant by a combination of five key microdensitometric, karyometric and maturation parameters. CONCLUSION: DNA microdensitometry, karyometry and maturation parameters have independent abilities in identifying individual malignant melanomas. Coevaluation of various cytometric features and maturation profiles offers better diagnostic ability in separating benign nevi from MM.

Adolescent↗

PubMed1986

Genetic EEG patterns in febrile convulsions--a multivariate analysis.

Genetically determined EEG patterns being found during a longterm follow-up of children with febrile convulsions are subjected to a multivariate statistical analysis. The study is mainly concerned with the examination of interrelationships between spikes and waves, theta-rhythms, and photosensitivity. The three patterns form two-categorial variables (occurrence yes, no) and enter a three-way contingency table. Associations between the variables are examined by fitting a log-linear model to the data. Three effects in the structure of the contingency table are statistically significant: the main effect of theta-rhythms which are relatively frequent in the group, and the two-variable-interactions of spikes and waves with theta-rhythms and photosensitivity respectively. The results of the study emphasize that combinations of different genetic factors are important in the pathogenesis of febrile convulsions.

Analysis of Variance↗

PubMed1998

Multivariate analysis of predictors of hematoma enlargement in spontaneous intracerebral hemorrhage.

BACKGROUND AND PURPOSE: We conducted this study to determine, through use of multivariate analyses, the independent predictors of hematoma enlargement occurring after hospital admission in patients with spontaneous intracerebral hemorrhage (i.c.h.). METHODS: We reviewed 627 patients with ICH admitted within 24 hours of onset. The first CT was performed at admission and the second within 24 hours of admission, and a blood sample was taken for laboratory examinations. Univariate and multivariate analyses were performed to assess the relationships between hematoma enlargement and time from onset, consciousness level, CT findings, amount of alcohol consumption, systolic blood pressure at and after admission, clinical outcome, and hematologic parameters. RESULTS: Eighty-eight patients (14.0%) showed enlarged hematomas after admission. Multivariate analyses revealed that the following five factors were independently associated with hematoma enlargement: the time from onset (odds ratio [OR], 0.26 for a 1-SD change; 4.9 hours; P < 0.001); the amount of alcohol consumption (OR, 1.50 for 1 SD; 46.3 g/d; P = 0.002); the sharp of hematoma (OR, 1.40 for 1 SD; 0.45 round; P = 0.006); the presence of consciousness disturbance (OR, 1.38 for 1 SD; 0.50 coma; P = 0.026); and the level of fibrinogen (OR, 0.74 for 1 SD; 87.1 mg/dL; P = 0.042). Hematoma enlargement was an independent factor increasing the mortality rate in the ICH patients (OR, 1.57; P < 0.001). CONCLUSIONS: A particularly high likelihood of hematoma enlargement was observed in patients who (in order of importance) were admitted shortly after onset, who were heavy drinkers; who had an irregularly shaped hematoma, whose consciousness was disturbed, and who had a low level of fibrinogen.

Aged↗

PubMed2006

Integrated mechanistic and data-driven modelling for multivariate analysis of signalling pathways.

Mathematical models of highly interconnected and multivariate signalling networks provide useful tools to understand these complex systems. However, effective approaches to extracting multivariate regulation information from these models are still lacking. In this study, we propose a data-driven modelling framework to analyse large-scale multivariate datasets generated from mathematical models. We used an ordinary differential equation based model for the Fas apoptotic pathway as an example. The first step in our approach was to cluster simulation outputs generated from models with varied protein initial concentrations. Subsequently, decision tree analysis was applied, in which we used protein concentrations to predict the simulation outcomes. Our results suggest that no single subset of proteins can determine the pathway behaviour. Instead, different subsets of proteins with different concentrations ranges can be important. We also used the resulting decision tree to identify the minimal number of perturbations needed to change pathway behaviours. In conclusion, our framework provides a novel approach to understand the multivariate dependencies among molecules in complex networks, and can potentially be used to identify combinatorial targets for therapeutic interventions.

Apoptosis↗

PubMed1993

Surgical lateral clearance in resected rectal carcinomas. A multivariate analysis of clinicopathologic features.

BACKGROUND: Incomplete removal of the tumor is the main cause of local recurrence in rectal carcinomas; this often occurs at the lateral aspects devoid of the peritoneum. The authors examined prospectively 80 resected rectal carcinoma specimens in an attempt to discover a reliable method to detect lateral resection margin (LRM) involvement by these tumors and to identify pathologic factors that would be prognostically important. METHODS: In each of the 80 resected specimens, the whole tumor was embedded, and whole-mount sections of the entire tumor and the surrounding mesorectum were examined after serial transverse slicing. The distance from the outermost part of the tumor to the LRM (surgical clearance) was measured. RESULTS: Six (7.5%) of the 80 specimens showed LRM involvement (defined as surgical clearance < or = 1 mm) in the single slice seen macroscopically to have the deepest tumor invasion, whereas 16 specimens (20%) were found to have LRM involved after examining all slices microscopically. Surgically clearance had a strong inverse relationship with Dukes staging (P < 0.001) and depth of tumor invasion (P = 0.001). The overall local recurrence rate was 28%; it was much higher (53%) in the patients who had LRM involved by tumor. As a whole, local recurrence was related significantly to LRM involvement (P = 0.006). Survival rates were correlated with macroscopic (n = 3) and microscopic (n = 13) features of the resected specimens using Cox multivariate regression analysis. Three of the nine pathologic parameters isolated (i.e., surgical clearance, cellular differentiation, and number of involved pericolic lymph nodes) were identified as favorable independent prognostic factors. CONCLUSIONS: Local recurrence is related closely to LRM involvement. Embedding and examining the entire tumor and mesorectum is the only reliable and satisfactory means of assessing LRM. Detailed pathologic study on the resected tumor is important when assessing the prognosis.

Adenocarcinoma↗

PubMed2001

A 35-item version of the Caring Dimensions Inventory (CDI-35): multivariate analysis and application to a longitudinal study involving student nurses.

The present study was designed to investigate the perceptions of caring among student nurses and how these develop throughout the course of a programme of pre-registration nurse education. A 35-item version of the caring dimensions inventory was administered to a cohort of nursing students in a department of nursing in Scotland at entry to the programme, after 12 months and after 24 months on the programme. Caring was largely perceived through a technical dimension, demonstrated by factor analysis, but other dimensions such as intimacy, support and unnecessary and inappropriate aspects of nursing also became apparent as students progressed through the programme.

Adult↗

PubMed1993

A multivariate analysis of psychological factors related to body mass index and eating preoccupation in female college students.

Using a composite questionnaire, we measured the degree to which preoccupation with eating and body mass index (BMI) are related to a series of psychological measures in a sample of female college students. Eating preoccupation was measured using a set of questions designed to be free of affective content. Thirty volunteers filled out the questionnaire; their height and weight were measured under standard conditions. Correlations showed that BMI was positively related to the variables Depression and Emotional Response to Environmental Stimuli, while Eating Preoccupation was most closely related to Anxiety. Principal components analysis revealed two factors, one containing measures of positive emotionality, and one containing Eating Preoccupation and measures of negative emotionality, with BMI loaded on both components. These factors reflect the relationship of BMI to measures of both positive and negative emotionality. Positive emotionality may be a reflection of activation of a neurobehavioral system, the behavioral facilitation system, while negative emotionality may be a reflection of activation of the behavioral inhibition system. The overweight women in this study appeared to have high levels of activation of one or both systems, while the underweight women appeared to have low activation of both systems. Approaches to the study of obesity in women should take into account the fact that positive emotionality, as well as negative emotions such as depression and anxiety, may be related to BMI, and that eating preoccupation appears to be a subset of overall anxiety.

Adolescent↗

PubMed1991

Multivariate analysis of donor-specific versus random transfusion protocols in haploidentical living-related transplants.

A total of 127 haploidentical living-related transplants have been performed at our institution since March 1986. A donor-specific transfusion plus azathioprine protocol was used until July 1988 (n = 74) and a random transfusion (RT) protocol without AZA used thereafter (n = 53) in an effort to decrease risk of recipient sensitization and reduce the burden on the prospective donor. All patients were given cyclosporine 8 mg/kg/day orally beginning 1 week prior to transplantation. Immunosuppression was similar in both groups and consisted of triple induction therapy with prednisone, CsA, and AZA. A positive T cell crossmatch eliminated the potential donor. Seven individuals (9.6%) were sensitized in the DST group and 1 (1.9%) in the RT group, leaving 67 and 52 patients in the two groups of the study, respectively. Groups were similar with respect to age, sex, history of pregnancy in female patients, peak and baseline panel-reactive antibody (PRA), DR match, and prior transplants. The groups differed slightly with respect to AB antigens shared, with an advantage in the RT group. Actuarial graft survival was not statistically significantly different between the two groups, with 2-year graft survival of 95% in the DST and 91% in the RT group (log rank, P = 0.16). Patients in the RT group had significantly more rejection episodes and had them sooner than their counterparts in the DST group. At the end of 1 year, 50% of patients in the DST group had at least 1 rejection episode, compared with 75% of patients in the RT group (P = 0.0008). Multivariate (Poisson) analysis of 10 variables was performed, with an overall model P-value of 0.0001. Only DST (P = 0.0001) and pregnancy (P = 0.015) were significant predictors of rejection episodes, both protective. The difference in rejection episodes and the timing with which they occur has not yet translated into a significant difference in graft survival between DST and RT groups.

Adult↗

PubMed1998

Estimating urea clearance in patients on continuous ambulatory peritoneal dialysis: a multivariate analysis.

The purpose of this study was to determine if Kt/V urea in continuous ambulatory peritoneal dialysis (CAPD) could be estimated by a multivariate model based upon simple clinical observations. The study included 439 clearance studies in 301 CAPD patients followed in 8 dialysis centers. Weekly urea clearance, 24 h urine volume and 24 h drain volume were normalized to body water by the formulae of Watson (Kt/V, UV/V and DV/V respectively). Adequate dialysis was defined as Kt/V > or = 2.0 weekly. Subjects at 2 units were used to derive the models, while others were used for model validation. Stepwise multiple linear regression was performed on the derivation set (DS) to identify the clinical variables that correlated with Kt/V. The model was then used to estimate Kt/V for the validation set (VS). In the DS, 110 clearance studies were performed in subjects with residual renal function. Multiple linear regression showed that weekly Kt/V was defined by the expression: Kt/V=1.48 + 24.1 (UV/V) + 2.92(DV/V) - 0.049 (serum creatinine) (r=0.750, p<0.001). In 204 VS studies, the correlation between estimated and measured Kt/V was 0.633. There were marked differences in the proportion of adequately dialyzed patients when Kt/V estimated from the formula shown was <2.0, between 2.0 and 2.3, and >2.3 weekly (7.9%, 54.7% and 79.7%, respectively; p 2.3 weekly (8.1%, 68.8%, and 100%, respectively; p<0.001). The risk of low Kt/V can be estimated by multivariate linear models requiring only simple clinical measurements.

Female↗

PubMedDate not supplied

A multivariate analysis of HIV-1 protease inhibitors and resistance induced by mutation.

This paper describes the use of the multivariate statistical procedure principal component analysis as a tool to explore the inhibitory activity of classes of protease inhibitors (PIs) against HIV-1 viruses (wild type and more-frequent single mutants, V82A, V82F, and I84V) and against protease enzymes. The analysis of correlations between biological activity and molecular descriptors or similarity indexes allowed a reliable classification of the 51 derivatives considered in this study. The best results were obtained in the case of the I84V mutant for which a high number of predictions was achieved. On this basis, this statistical approach is proposed as a reliable method for the prediction of the activity of PIs, for which the data against mutant strains have not been reported.

Drug Resistance, Viral↗

PubMed1984

Multivariate analysis of familial and non-familial influences for commonality in drug use.

A multivariate behavioral genetic analysis of common legal drug usage was performed on data from 238 Swedish families. By calculating cross-covariances between parents and offspring for pairs of traits, familial and non-familial correlations were computed to determine the extent to which pairs of measures share the same familial and non-familial influences. Factor analyses resulted in a 3- and a 2-factor solution for the familial and non-familial correlations, respectively. This suggests that familial and non-familial influences for drug usage are structured differently. If replicable, these results also suggest that the phenotypic structure reflects familial factors more than non-familial influences.

Adult↗