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PubMed1998

Identification of animal species in ground meat mixtures by multivariate analysis of isoelectric focusing protein profiles.

The present work investigates the possibility of constructing a multivariate calibration model to predict the composition of ground meat with respect to animal species, based on intensity profiles from isoelectric focusing of water-soluble proteins in mixtures of ground meat. Samples containing various amounts of beef, pork and turkey meat were analyzed by isoelectric focusing in immobilized pH-gradients. The gels were photographed and the images transferred to a digital format. The digital images were processed in order to reduce background and optimize signal strength. Resulting gel profiles were analyzed by multivariate regression allowing the determination of sample composition with prediction errors close to 10%.

Algorithms↗
PubMed2003

Advances in multivariate analysis in pharmaceutical process development.

In the last five years, reports of the application of multivariate methods in pharmaceutical process research and development have burgeoned. Examples range from the widespread adoption of statistical experimental design for screening and process optimization to the implementation of workflows that integrate multivariate characterization, experimental design and the development of quantitative structure-property relationships. Having learned from the application of these techniques in drug discovery and armed with modern high-throughput experimentation platforms, practitioners are discovering the power of experimental design and multivariate methods for shortening process development timelines.

Drug Evaluation, Preclinical↗
PubMed1995

Multivariate analysis of risk factors for postoperative pneumonia.

PURPOSE: Many risk factors for postoperative pneumonia have been identified, but those for the progression from atelectasis to pneumonia have been poorly examined. We undertook the present study to find risk factors for the progression from atelectasis to pneumonia. PATIENTS AND METHODS: We completed a retrospective analysis of 2,969 patients who underwent major abdominal surgery during the past 13 years. RESULTS: Pneumonia developed in 45 patients (1.5%), and postoperative atelectasis with a high risk for the subsequent infection occurred in 44 patients in whom pneumonia did not develop. A series of 13 variables was compared in the two patient categories. By multivariate discriminant analysis, we identified three independent significant correlates of the development of postoperative pneumonia: blood loss of more than 1,200 mL during surgery, age over 65 years, and preoperative utilization of inhalation therapy devices. CONCLUSION: This study shows that a substantial number of cases of postoperative pneumonia can be prevented.

Aged↗
PubMed1990

Prognostic factors of hepatocellular carcinoma in the west: a multivariate analysis in 206 patients.

To investigate the prognostic factors in Western patients with hepatocellular carcinoma, 206 patients with confirmed diagnoses of hepatocellular carcinoma were studied in terms of survival. All patients were diagnosed between 1983 and 1987. A multivariate survival analysis (Cox regression model) using clinical, biochemical, ultrasonographical and pathological data obtained at diagnosis disclosed that bilirubin (p = 0.0001), ascites (p = 0.0001), toxic syndrome (defined by the presence of weight loss greater than 10% premorbid weight, malaise and anorexia) (p = 0.009), blood urea nitrogen (p = 0.025), tumor size (p = 0.001), gamma-glutamyltranspeptidase (p = 0.0006), age (p = 0.0005), serum sodium (p = 0.003) and presence of metastases (p = 0.002) were independent predictors of survival. According to the contribution of each of these factors to the final model, a prognostic index was constructed allowing division of patients in different groups according to their relative risk of death: RRD = EXP (Age x 0.03 + Ascites x 0.8281 + BUN x 0.0137 + Serum sodium x (-0.0538) + gamma-Glutamyltranspeptidase x 0.0019 + Bilirubin x 0.0734 + Tumor size x 0.33 + Toxic syndrome x 0.4965 + Metastases x 0.55). These results facilitate the stratification of hepatocellular carcinoma patients to design and evaluate future controlled trials.

Adult↗
PubMed2000

What patients can survive disease free after complete resection for hepatocellular carcinoma?: A multivariate analysis.

BACKGROUND: Although there have been extensive studies to determine risk factors affecting survival after resection for hepatocellular carcinoma (HCC), we still do not know which patients can survive disease free after curative resection. This study was undertaken to determine independent risk factors affecting the length of disease-free survival. METHODS: 171 patients, who survived disease free more than 1 year after curative resection, were divided into four groups according to the disease-free period: Group I (n = 96) for the patients with intrahepatic recurrence between 1 and 3 postoperative years, Group II(n = 27) for those between 3 and 5 years, Group III (n = 40) for those between 5 and 10 years and Group IV (n = 8) for those without recurrence within 10 years. The 37 variables (host factors, tumor factors, non-tumor liver factors, surgical factors) were compared among the four groups. Activity of hepatitis and hepatic fibrosis was scored by the Histological Activity Index (HAI). In a multivariate study, possible prognostic variables with a statistical difference in the disease-free survival rate among each category were preliminarily selected from the 37 variables and the independent variables were finally selected using a proportional hazard analysis. RESULTS: The patients' age, indocyanine green retention rate, microscopic tumor capsular invasion and portal invasion, cell differentiation, extent of hepatectomy, aggressiveness of chronic hepatitis and inflammatory activity assessed by HAI score were significantly different among the four groups. In the multivariate analysis, the following variables were selected as the independent determinants favorable for achieving a longer disease-free period: younger age, lower indocyanine green retention rate, solitary HCC with expansive growth, no microscopic portal invasion and lower activity of co-existing hepatitis. CONCLUSIONS: The importance of inflammatory activity in addition to aging, hepatic reserve and tumor characteristics was confirmed as a risk factor for recurrence by multivariate analysis. To achieve better disease-free survival, not only early detection but also suppression of co-existing hepatitis is necessary.

Aged↗
PubMed2000

Are clinical parameters valuable prognostic factors in childhood primitive neuroectodermal tumors? A multivariate analysis of 105 cases.

BACKGROUND: Medulloblastoma is one of the most frequent brain tumors in children. Long-term survivors are often confronted with serious late sequelae, caused by the therapy. Therefore, prognostic markers must be identified that allow the children to be assigned to different treatment schedules according to their predicted outcome. PATIENTS AND METHODS: The medical data of 110 children with a medulloblastoma or central primitive neuroectodermal tumor (PNET), that were admitted to the Emma Kinderziekenhuis in Amsterdam were analyzed by univariate and multivariate analyses. RESULTS: In univariate analysis the following characteristics had a significant influence on progression free survival (PFS): (a) presence of meningeal metastases at the time of diagnosis, (b) presence of tumor cells in the cerebrospinal fluid before or after surgery, (c) extent of resection, (d) necessity for permanent cerebrospinal fluid (CSF) shunting and (e) radiation dose to the posterior fossa. On multivariate analysis only the presence of metastases and the radiation dose to the posterior fossa retained significance. CONCLUSION: At the time of diagnosis, no reliable clinical prognostic markers are available for the majority of patients. Further molecular studies must be undertaken to identify such prognostic factors.

Adolescent↗
PubMed1992

A multivariate analysis of weight-loss behavior.

This study used a theoretical framework with multiple variables in multivariate analyses (factor, multiple regression, and path analyses) to investigate the sociopsychological predictors of weight loss. Responses from 309 participants of a comprehensive weight-loss program indicated that self-assurance was the most significant predictor of actual weight loss, followed by weeks completed. Other factors, such as program satisfaction and perceived importance, indirectly predicted weight loss through the intervening variables of self-assurance and weeks completed. Differences in the factors predicting weight loss were observed between completers and dropouts. The implications of these results for professionals concerned with weight control are discussed.

Adult↗
PubMed2006

Use of multivariate analysis to extract latent variables related to level of production and lactation persistency in dairy cattle.

Multivariate factor analysis and principal component analysis were used to decompose the correlation matrix of test-day milk yields of 48,374 lactations of 21,721 Italian Simmental cows. Two common latent factors related to level of production in early lactation and lactation persistency, and 2 principal components associated with the whole lactation yield and persistency were obtained. Factor and principal component scores were treated as new quantitative phenotypes related to prominent features of lactation curve shape. Genetic parameters were estimated by univariate and bivariate animal models. Estimates of heritability were moderately low for both latent factors (0.13 for persistency and yield early in lactation). Heritabilities of the principal component related to total lactation yield and 305-d yield were similar (0.19 and 0.20, respectively). Finally, heritability was quite low for the principal component related to lactation persistency (0.07). Repeatabilities between lactations were about 0.27 for both latent factors, around 0.4 for the first principal component and 305-d yield, and 0.11 for the second principal component. Moderate genetic correlation among common factors (0.26) and their high genetic correlation with total lactation yield (>0.60) suggest that selection can be used to change the shape of lactation curve as well as improve yield. Scores of the second principal component can be used to genetically improve persistency while maintaining constant total lactation yield.

Analysis of Variance↗
PubMed2000

Prognostic factors in Hodgkin's disease: multivariate analysis of 327 patients from a single institution.

On the basis of a retrospective study of 327 patients with Hodgkin's disease (HD), the prognostic significance of several factors, accepted previously and recently proposed, has been analyzed with regard to response to treatment and the survival time. Multivariate regression analysis strongly decreased the number of potentially prognostic parameters. The only independent, pretreatment factors negatively influenced by either time of survival or response to treatment were the following: age at diagnosis of more than 45 years, advanced (IIIB/IV) clinical stage, poor clinical status according to Karnofsky's scale (score less than 70), presence of systemic symptoms, mixed cellularity/lymphocyte depletion histological type, multisite peripheral nodal localization of the disease, abdominal lymphadenopathy, and large primary tumor mass (bulky disease). Short time to achieve complete remission (during the first four courses of chemotherapy) has proven to be significantly positive predictive factor. Cumulative dose of cytostatics lower than programmed was a significantly negative prognostic factor that correlated with a shorter time of survival. Lack of or a too-low dose of radiotherapy had the same predictive value. High activity of serum lactate dehydrogenase correlated moderately with poor response to the first-line treatment but did not influence the survival time. Other clinical, morphological, and biochemical parameters influenced neither the prognosis nor the response to treatment. Additionally, immunohistochemical examinations for proliferating cell nuclear antigen and the protein products of the p53 and bcl-2 genes were performed on the lymph nodes obtained from the patients with HD. High expression of proliferating cell nuclear antigen, p53, and BCL-2 correlated with poor response to the treatment and/or short time of survival. Statistical analysis has led us to the conclusion that the pretreatment expression of these oncoproteins can be taken into consideration as a new prognostic factor in HD.

Adolescent↗
PubMed1997

Multivariate analysis of pathophysiological factors in reflux oesophagitis.

BACKGROUND: Reflux oesophagitis is considered a multifactorial disease, but the respective roles of the main factors involved in its pathophysiology have not been clearly established. AIMS: To attempt to assign these roles by means of a multivariate logistic regression analysis of the main parameters associated with reflux oesophagitis. PATIENTS: Eighty seven patients with gastro-oesophageal reflux disease were studied: 41 without oesophagitis and 46 with reflux oesophagitis grade 1 to 3. METHODS: (1) Monovariate comparison of patients' characteristics and of parameters derived from in hospital 24 hour oesophageal pH monitoring, oesophageal manometry, double isotope gastric emptying studies, and basal and pentagastrin stimulated gastric acid and pepsin output determinations, between patients with and without oesophagitis. (2) Multivariate logistic regression analysis including the parameters significant in the monovariate analysis. RESULTS: Among the 16 significant parameters from monovariate analysis, three significant independent parameters were identified by multivariate logistic regression analysis: number of refluxes lasting more than five minutes, reflecting oesophageal acid clearance (p = 0.002); basal lower oesophageal sphincter pressure (p = 0.008); and peak acid output (p = 0.012). These three parameters were not correlated with each other. The multivariate model was highly discriminant (correct classification of 81.3% of the cases (95% confidence intervals 0.723, 0.903). Risk for oesophagitis increased as a function of the tercile threshold values of the three parameters. Odds ratios of the three parameters for oesophagitis risk were similar, regardless of whether they were calculated when the patients were compared as a function of oesophagitis grade or the presence or absence of oesophagitis. CONCLUSIONS: This multivariate approach adds evidence that impaired oesophageal acid clearance and hypotonic lower oesophageal sphincter are the two major independent pathophysiological factors of oesophagitis, but also showed that the acid secretion level is an independent pathophysiological factor.

Adult↗
PubMedDate not supplied

Assessment of chromatographic peak purity of drugs by multivariate analysis of diode-array and mass spectrometric data.

Numerous multivariate chemometric approaches have been developed for LC-UV data acquired using a diode-array detector (DAD), but these methods have not been widely exploited for LC-MS data. Principal component analysis (PCA) and subsequent axis rotation within the reduced factor space are assessed for LC-DAD and LC-MS data as approaches for estimating the number of components (i.e. the rank of the data) under a single chromatographic peak for compounds whose UV-spectra are very similar. Multivariate techniques for LC-DAD data are shown to suffer from inherent limitations of sensitivity for the minor components. The novel technique in LC-MS of plotting the rotated PCA data in two-dimensional factor space generates characteristic ion clusters, giving a visual criterion of peak purity. Single ion chromatograms produced subsequently confirm the profile of each coeluting component and give evidence of the degree of peak overlap. The application of this new chemometric technique to the detection of low levels of coeluting impurities by LC-MS is discussed as a novel approach for the validation of LC separations in pharmaceutical research and development.

Chromatography, Liquid↗
PubMed1992

Religion and education as mediators of attitudes: a multivariate analysis.

The transmission of social attitudes has been investigated as a possible model of cultural inheritance in a sample of 3810 twin pairs from the Australian National Health and Medical Research Twin Registry. Six social attitude factors were identified and univariate genetic models fitted to scores on each factor. A joint multivariate genetic analysis of the six attitude factors, church attendance, and education indicated that the attitudes were correlated--the same genes and shared environments influenced more than one attitude factor. A current controversy regarding social attitudes is whether the significant loadings on this shared environmental component represent true cultural influences or are actually the genetic consequences of phenotypic assortative mating for church attendance and educational attainment (Martin et al., 1986). In our data, church attendance is almost entirely due to the impact of the shared environment. The large shared environmental component on church attendance also accounts for a substantial part of the family resemblance in social attitudes, suggesting that not all of the apparent cultural effects found in earlier studies can be ascribed to the genetic effects of assortative mating. However, church attendance and education do not completely account for the cultural component. Therefore, effects in addition to church attendance, education, and assortative mating for church attendance and education must be involved in the cultural component of the inheritance of attitudes.

Adolescent↗
PubMedDate not supplied

Complementarity of blue dye and isotope in sentinel node localization for breast cancer: univariate and multivariate analysis of 966 procedures.

BACKGROUND: The hypothesis that sentinel lymph node (SLN) mapping in breast cancer patients is optimized by combining blue dye and isotope is reasonable and intuitive. Despite this, few studies examine in detail the factors contributing to the success of these techniques, either individually or in combination. METHODS: During a time period of 21/2 years, 1000 consecutive patients at Memorial Sloan-Kettering Cancer Center had SLN mapping performed by using both blue dye and isotope, with preoperative lymphoscintigraphy (LSG). Among the 966 patients with invasive cancer, 12 variables were examined for their correlation with the success of SLN localization by blue dye, by isotope, and by the combined method, using univariate and multivariate models. RESULTS: By univariate analysis, blue dye success was more frequent in association with: a positive LSG (P = .02), age < or = 60 (P < .0005), a previous surgical biopsy (P = .03), and an outer quadrant tumor (P < .0005). Isotope success was more frequent with a positive LSG (P < .0005), age < or = 60 (P = .004), and intradermal isotope injection (P < .0005). Combined (dye and/or isotope) success was more frequent when there was a positive LSG (P < .0005), age < or = 60 (P = .006) and intradermal isotope injection (P < .0005). In multivariate analysis, blue dye success remained uniquely associated with outer quadrant tumor location (P < .0005), and isotope success was uniquely associated with intradermal isotope injection (P = .012). Combined success was more frequent with a positive LSG (P < .0005), age < or = 60 (P = .033), and intradermal isotope injection (P = .003). CONCLUSIONS: The five variables associated with successful SLN localization by blue dye or by isotope overlap but are not identical. Only three of these, intradermal isotope injection, a positive LSG, and age < 60, predicted success by the dye-isotope combination in the multivariate model. Dye and isotope complement each other, and SLN biopsy for breast cancer should use both.

Breast Neoplasms↗
PubMed1989

Multicomponent analysis of near-infrared spectra of anesthetized rat head: (II). Quantitative multivariate analysis of hemoglobin and cytochrome oxidase by non-negative least squares method.

We developed a method for quantitating absolute value of Hb oxygenation and that of redox state of cyt. aa3 on the basis of multiple regression analysis of near-infrared spectrophotometric data. Flattening of the spectrum of Hb in both RBC suspension and the brain in situ was observed. This phenomenon was explained by localization of Hb within RBC for in vitro flattening, and by localization of RBC within the vessels as well as deformation of RBC in the microcirculation in vivo. Under resting air-breathing conditions, So2 and redox state of cyt. aa3 were estimated to be 50-70% and over 90%, respectively. Increase in FIO2 up to 3 ATA O2 caused stepwise increase in So2, whereas cyt. aa3 was fully oxidized when the animal inspired O2 under 1 ATA. Problems which must be solved for more accurate estimation of absolute values of So2 and redox state of cyt. aa3 were described and discussed.

Algorithms↗
PubMed2004

Taxonomic discrimination of flowering plants by multivariate analysis of Fourier transform infrared spectroscopy data.

Fourier transform infrared spectroscopy (FTIR) provides biochemical profiles containing overlapping signals from a majority of the compounds that are present when whole cells are analyzed. Leaf samples of seven higher plant species and varieties were subjected to FTIR to determine whether plants can be discriminated phylogenetically on the basis of biochemical profiles. A hierarchical dendrogram based on principal component analysis (PCA) of FTIR data showed relationships between plants that were in agreement with known plant taxonomy. Genetic programming (GP) analysis determined the top three to five biomarkers from FTIR data that discriminated plants at each hierarchical level of the dendrogram. Most biomarkers determined by GP analysis at each hierarchical level were specific to the carbohydrate fingerprint region (1,200-800 cm(-1)) of the FTIR spectrum. Our results indicate that differences in cell-wall composition and structure can provide the basis for chemotaxonomy of flowering plants.

Biomarkers↗
PubMed2005

Multivariate analysis of trace metal levels in tannery effluents in relation to soil and water: a case study from Peshawar, Pakistan.

Tannery effluents and relevant ground water and soil samples collected from various tanning industries of Peshawar were analyzed for Na, Ca, K, Mg, Fe, Mn, Cr, Co, Cd, Ni, Pb and Zn by the AAS method. The metal concentration data for the three media are reported in terms of basic statistical parameters, metal-to-metal correlations and linear regression analyses. Metal distributions in the three media were quite divergent and showed non-normal distributions with high standard deviation and skewness parameters. Sodium exhibited the highest mean levels of 1,277mg/L, 881mg/L and 12,912mg/kg in the effluent, ground water and soil samples, respectively. Among other metals, Cr concentrations were 410mg/L, 0.145mg/L, 100mg/kg and Ca, 278mg/L, 64.8mg/L, and 2,285mg/kg in the effluent, ground water and soil samples, respectively. Some significant correlations were observed between effluent and soils in terms of Na, Cr, Ni, Co and Pb. The ground water-soil interrelationship suggested that Na levels in the soil and ground water were significantly correlated with each other (r=0.486, P<0.01). Similarly, Cr in the soil is strongly correlated with Ca in ground water (r=0.486, P<0.01). These results were duly supported by the linear regression analysis of data. The source identification studies conducted using Principal Component Analysis (PCA) and Cluster Analysis (CA) evidenced that ground water and soil were being contaminated by the toxic metals emanating from the tannery effluents.

Cluster Analysis↗
PubMed2006

Multivariate analysis of heavy metal contamination in urban dusts of Xi'an, Central China.

Though there are many studies of heavy metal contaminations of urban dusts in developed countries, little attention has been paid to this kind of study in developing countries, including China. Therefore, a series of investigations were performed to provide heavy metal signatures of urban dusts and to evaluate potential sources in Xi'an, Shaanxi Province. Sixty-five samples of urban dusts were collected in Xi'an. Then Ag, Cr, Cu, Mn, Pb and Zn concentrations were determined by using atomic absorption spectrophotometry, and As, Hg and Sb concentrations by atomic fluorescence spectroscopy. The results indicate that, in comparison with Chinese soil, urban dusts in Xi'an have elevated metal concentrations as a whole, except those of arsenic and manganese. These concentration levels are comparable to those in other studies. Correlation coefficient analysis, principal component analysis (PCA) and cluster analysis (CA) were performed and three main sources with corresponding cluster elements were identified: (1) Ag and Hg have commercial and domestic sources; (2) Cr, Cu, Pb, Sb and Zn are mainly derived from industrial sources, combined with traffic sources as well for Pb and Zn; (3) As and Mn come mainly from soil sources, and As also has an industrial source. Based on PCA and CA analyses, manganese was selected as the reference element, and heavy metal enrichment factors (Efs) were calculated, which in turn further confirms the source identification. Also, Efs give an insight of human influence degree of urban dusts.

Arsenic↗