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PubMedDate not supplied

Direct determination of lycopene content in tomatoes (Lycopersicon esculentum) by attenuated total reflectance infrared spectroscopy and multivariate analysis.

Lycopene is a potent antioxidant that has been shown to play critical roles in disease prevention. Efficient assays for detection and quantification of lycopene are desirable as alternatives to time- and labor-intensive methods. Attenuated total reflectance infrared (ATR-IR) spectroscopy was used for quantification of lycopene in tomato varieties. Calibration models were developed by partial least-squares regression (PLSR) using quantitative measures of lycopene concentration from liquid chromatography as reference method. IR spectra showed a distinct marker band at 957 cm(-1) for trans Carbon-Hydrogen (CH) deformation vibration of lycopene. PLSR models predicted the lycopene content accurately and reproducibly with a correlation coefficient (sigma) of 0.96 and standard error of cross-validation <0.80 mg/100 g. ATR-IR spectroscopy allowed for rapid, simple, and accurate determination of lycopene in tomatoes with minimal sample preparation. Results suggest that the ATR-IR method is applicable for high-throughput quantitative analysis and screening for lycopene in tomatoes.

Carotenoids↗
PubMed1995

A multivariate analysis of kinanthropometric profiles of elite female orienteers.

The purpose of this study was to examine the relevance of various kinanthropometric features of elite female orienteers in terms of success at the Student World Orienteering Championships (SWOC)(1992). Participants at this competition were divided into successful (final placing in top 35; n = 12) and less successful (final placing below 35; n = 11) competitors. A non-orienteering reference group was used to enable the identification of any sport specific factors. Measurements of the orienteering group were taken during the week of the SWOC and included 5 skinfold thicknesses, 2 limb girths, 2 bone breadths, 3 proportional lengths and 3 physical tests (grip strength, leg strength, flexibility). Using the results of these, percent adiposity, somatotypes and various anthropometric indices were also obtained. Age and adiposity variables were found to correlate significantly with competitive performance (p < 0.01). Discriminant function analysis successfully distinguished between the successful and less successful orienteers (Wilks' Lambda = 0.603; p < 0.01). There was no difference (p > 0.05) between the orienteering group and the reference group for the majority of the proportionality measures and similarily in the results of the physical tests. Adiposity values were higher in the non-orienteers. In conclusion, body composition measures discriminated between successful and less successful orienteers at a major event at an elite level. The primary difference between the orienteers and the reference group was in body composition rather than linear or proportional measures.

Adipose Tissue↗
PubMed1994

An important role of glomerular segmental lesions on progression of IgA nephropathy: a multivariate analysis.

The independent predictors of progression of IgA nephropathy (IgAN) were investigated by multivariate life table analysis, using Cox's proportional hazard model, in 225 patients with IgAN diagnosed by renal biopsy (Bx). There were 105 men and 120 women. Mean age at Bx was 32.5 years. The follow-up period following Bx was 4.0 +/- 2.6 yrs, ranging from 5 months to 11 yrs. The clinical parameters analyzed were age at the time of discovery of the disease, age at Bx, intervals from discovery to Bx, presence or absence of macrohematuria, and clinical data at Bx such as presence or absence of hypertension, the degree of hematuria, the amount of urinary protein excretion, serum creatinine and serum IgA concentration. The following immunopathological parameters were also examined; glomerular hypercellularity index, percentage of glomeruli associated with segmental lesions such as tuft adhesions, crescents and segmental sclerosis, percentage of obliterated glomeruli by global sclerosis, severity of interstitial infiltration, fibrosis, arterial wall thickening, arterial hyaline changes, and intensity of the depositions of IgG, IgA, IgM, C3, C1q and fibrinogen by immunofluorescent study. Among all clinical and pathologic parameters examined, the following parameters were proved to be significant independent predictors of progression of IgAN: serum creatinine exceeding 1.5 mg/dl in men and 1.3 mg/dl in women, proteinuria over 2 g/day, segmental lesions involving more than 25% of glomeruli and interstitial fibrosis occupying more than 25% of cortical area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1982

Multivariate analysis of HLA-disease associations.

A multivariate procedure is presented for the analysis of HLA-disease associations. This formulation explicitly accounts for the inner correlations of the HLA complex itself, both within loci (arising from the fact that multinomial allelic frequencies must sum to unity) and between loci (arising from a failure of independent assortment). The analysis yields a single test criterion for association of the HLA complex, as a whole, with the disease in question: this criterion has an approximately chi square distribution. The overall test may conveniently be partitioned into a variety of interesting and independent subtests, so a decomposition of the problem is possible. The analysis is illustrated with data derived from a study of guttate psoriasis by Williams et al. (1976, British Journal of Dermatology 95, 163-167). Extensions to related problems are indicated.

Alleles↗
PubMed1986

[The application of multivariate analysis to the radioallergosorbent test (RAST)].

Multivariate statistical analyses using principal component analyses (PCA) and Mahalanobis' method were applied to the quality control of radioallergosorbent test (RAST). Mites and foods allergen were analyzed by PCA method, and foods allergen were analyzed by Mahalanobis' method. The vast differences in the distribution on titers among the mites and the foods were observed. To evaluate the results of a test and the quality of kits for test statistically, it should be better to use multivariate analyses such as PCA or Mahalanobis' method.

Allergens↗
PubMed2002

Factors associated with clinically significant anastomotic leakage after large bowel resection: multivariate analysis of 707 patients.

The aim of this study was to determine by univariate and multivariate analyses the factors associated with clinically significant anastomotic leakage (AL) after large bowel resection. From 1990 to 1997 a series of 707 patients underwent colonic or rectal resection (without a stoma). Patients were divided into two groups: those with clinical anastomotic leakage (group 1) and those without it (group 2). AL occurred in 43 of 707 patients (6%). The overall mortality was 2.2% and was significantly higher in patients with AL than in those without: 5 of 43 (12%) versus 11 of 664 (1.6%), p < 0.001. Univariate analysis showed 15 variables associated with the risk of AL: previous abdominal or pelvic irradiation (p = 0.02), American Society of Anesthesiologists (ASA) score > 2 (p = 0.04), leukocytosis (p = 0.02), renal failure (p = 0.03), steroid treatment (p = 0.01), duration of operation (p = 0.001), intraoperative septic conditions (p = 0.006), total colectomy (p = 0.009), transverse colectomy (p = 0.02), difficulties encountered during anastomosis (p = 0.001), ileorectal anastomosis (p = 0.02), colocolic anastomosis (p = 0.01), abdominal drainage (p = 0.05), and blood transfusion intraoperatively (p = 0.006) and postoperatively (p = 0.001). Multivariate analysis showed that only preoperative leukocytosis (p = 0.04), intraoperative septic conditions (p = 0.001), difficulties encountered during anastomosis (p = 0.007), colocolic anastomosis (p = 0.004), and postoperative blood transfusion (p = 0.0007) were independent factors associated with AL. The risk of AL increased from a range of 12% to 30% if one risk factor was present, to 38% with two factors, to 50% with three factors. After colorectal resection and intraperitoneal anastomosis, a temporary protective stoma is proposed in selected patients with high risk factors for AL, as observed in our study.

Adolescent↗
PubMed1976

Multivariate analysis: data reduction and treatment evaluation.

In a recent article, Everitt (1975) discussed several problems with multivariate techniques. However, two useful applications of multivariate techniques were not covered. The present paper describes the use of factor analysis to reduce a large array of outcome variables to a statistically manageable number, and multivariate analysis of variance to determine the relative effectiveness of several treatment regimes where a single outcome variable cannot be specified. It is concluded that the advantages of a multivariate approach out-weigh the disadvantages, provided the researcher is careful in interpreting and reporting his results.

Alcoholism↗
PubMed1995

Impact of the Crohn's-like lymphoid reaction on staging of right-sided colon cancer: results of multivariate analysis.

The presence of lymphoid aggregates within the muscularis propria or pericolic fibroadipose tissue apposing invasive colorectal carcinoma, termed the Crohn's-like lymphoid reaction, has been related to improved patient length of survival according to univariate statistical analysis. We tested the Crohn's-like lymphoid reaction as an indicator of prognosis in a multivariate statistical analysis of 344 resected right-sided colonic cancers. Improved 5-year survival in univariate analysis was associated with low tumor grade, regular tubule configuration, expanding tumor growth pattern, prominent peritumoral lymphocytic infiltration, absence of tumoral invasion of extramural veins, all levels of intramural and extramural invasion short of widespread local tumor permeation, conspicuous Crohn's-like lymphoid reaction, and absence of both nodal metastasis and nodal-independent tumor nodules in pericolic fat. By the Cox proportional hazard model using the stepwise method, depth of tumor invasion, lymph node metastasis, Crohn's-like lymphoid reaction, and metastatic tumor nodules in pericolic fat retained independent prognostic significance. Combining the four variables to formulate pathological prognostic categories yielded a highly favorable prognostic group-92% 5-year survival and 95% confidence limits (88% to 96%)--encompassing 53% of the study population. It included all Dukes' stage A carcinomas, 66% of Dukes' stage B adenocarcinomas, and 11% of Dukes' stage C cancers. Lymph node metastases coupled with intramural and extramural extent of tumor invasion are the cornerstones of colorectal cancer staging. Addition of other variables improves prognostication for the cecum and ascending colon. From this study the Crohn's-like lymphoid reaction and metastatic tumor nodules in pericolic fat emerge as significant independent indicators of prognosis for right-sided colon cancer. Complex correlations of both indicators with nonselected variables were observed.

Adenocarcinoma↗
PubMedDate not supplied

Global analysis of lymphocyte gene expression: perturbation of H-9 cells by infection with distinct isolates of human immunodeficiency virus--an exposition by multivariate analysis of a host-parasite interface.

AIDS is a progressive disease associated with steady loss of helper T cells and several other functions. As the disease evolves, cytopathogenic human immunodeficiency (HIV) variants of increasing virulence can be isolated from the host. The HIV is an unusually variable genome by virtue of a low replication fidelity. In this report we describe our effort to test the hypothesis that there is a correlation between virus variability and cytopathogenicity, and further, that there is an "impact" of the virus infection on the expression of host cellular genes. To search for such a relationship, we infected H-9 cells (human CD4+ lymphoblastoid cell line) with each of 5 isolates of HIV of distinct origin and cytopathogenicity. To measure the influence of the virus infection on the expression of host cellular genes, shortly after infection, (3 h or 13 h), cells were radiolabeled and the radioactive polypeptides separated by two-dimensional gel electrophoresis. Radiofluorographs were prepared and analyzed to determine relative rates of biosynthesis of cellular polypeptides. To organize the large amounts of data found, cluster analysis and principal component analysis were used to expose the data in formats that allowed a model construction. The rates of biosynthesis of many cellular polypeptides were altered upon viral infection in terms of both enhancements and impairment of biosynthesis. Some of the variation in polypeptide synthesis was isolate-specific, while most alterations were of modest magnitude. There appears to be no "overall effect" associated with infection by a cytopathic variant of the virus. Polypeptides affected by the cytopathic variants were determined as targets for further investigation. The method used promotes the measurement of "ensemble" information that is characteristic of the process and it promotes the creation of models of virus action.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Does multivariate analysis of post-thaw sperm characteristics accurately estimate in vitro fertility of boar individual ejaculates?

The objective of this study was to determine if a multivariate pattern analysis of frozen-thawed sperm characteristics of boar semen of unknown fertility, thus identifying groups of ejaculates as "good" or "bad" freezers, would estimate their fertilizing potential in an in vitro embryo production (IVP) system. Frozen-thawed spermatozoa from a single ejaculate collected from 46 boars were evaluated for sperm motility and kinematic patterns, for sperm viability and for early changes in sperm membrane stability. All data generated were used for a multivariate pattern analysis (PATN; CSIRO, Canberra, Australia) which objectively classified all ejaculates within a data set in to one of two groups, categorised as "good" (n = 25) or "bad" (n = 21) according with their freezability. In vitro matured oocytes were exposed to 2000 or 4000 frozen-thawed spermatozoa per oocyte for 6h and then cultured in embryo culture medium for either 6h (assurance of fertilization) or 7 days (to collect data on embryo development). Rates of sperm oocyte penetration and of embryo development significantly (p < 0.05) increased in a sperm:oocyte ratio-dependent manner. A similar pattern was observed when sperm characteristics were grouped. Indeed, ejaculates classified as "good" showed significantly (p < 0.05) higher rates of oocyte penetration, cleavage and of blastocyst formation than those classified as "bad". However, variation was still present among individuals (ejaculates, boars) in their ability to produce blastocysts in vitro. It is therefore concluded that despite the presence of a relationship for ejaculates with good semen quality post-thaw (thus grouped as "good") to higher IVP-results, the presence of individual variation does not allow for an accurate estimation of in vitro fertility based solely on the frozen-thawed semen quality parameters of a single ejaculate from a given boar.

Analysis of Variance↗
PubMed1975

Multivariate analysis of early hominid pelvic bones.

Multivariate analyses of the acetabular and iliac parts of fossil hominid and extant hominoid pelvic bones show that (1) the best preserved fossil from Swartkrans (SK 3155) is more similar to the Sterkfontein pelvis (Sts 14) than either fossil is to any extant hominoid species; (2) of the living hominoids, all of the fossils are closer to modern Homo sapiens than to the apes; and (3) the robust and gracile forms of South African australopithecines are somewhat different from one another, the gracile form falling nearer to Homo sapiens, but neither form demonstrably closer to the pongids.

Acetabulum↗
PubMed2000

Predicting difficult intubation: a multivariable analysis.

PURPOSE: To develop a clinically useful and valid model for predicting difficult laryngoscopic tracheal intubation in patients with seemingly normal airways by adhering to the principles of multivariable model development. METHODS: This was an observational study performed at a tertiary-care teaching hospital. Preoperatively, 444 randomly selected patients requiring tracheal intubation for elective surgery were assessed. In addition, 27 patients in whom tracheal intubation was difficult, but were not assessed preoperatively, were assessed postoperatively. One assessor, blinded to the intubation information, collected the predictor variables. A reliable definition for difficult intubation was used and all attempts were made to eliminate sources of bias. Multivariable modeling was performed using logistic regression and the model was validated using the bootstrapping technique. RESULTS: Of the 461 patients included in the analysis, 38 were classified as difficult to intubate. Multivariable analysis identified three airway tests that were highly significant for predicting difficult tracheal intubation. These were: 1) "mouth opening", 2) "chin protrusion", and 3) "atlanto-occipital extension". Using these tests, a validated, highly reliable and predictive model is produced to determine the probability of difficult intubation for patients. At a selected probability cut-off value, the model is 86.8% sensitive and 96.0% specific. CONCLUSION: A simple and accurate multivariable model, consisting of three airway tests, is produced for predicting difficult laryngoscopic tracheal intubation. Additional studies will be required to determine the accuracy and feasibility of this model when applied to a large sample of new patients by multiple anesthesiologists.

Adult↗
PubMed2001

Shortcuts in genome-scale cancer pharmacology research from multivariate analysis of the National Cancer Institute gene expression database.

Application of a soft multivariate statistical procedure, called PLS, partial least squares modelling in latent variables or projections to latent structures, allows extensive exploitation of the enormous amount of information embedded in the National Cancer Institute gene expression and antitumour screen databases. Interpretation of the statistical results provides new significant biological insights such as classification of human tumour cell lines based on their gene expression patterns, evaluation of the influence of gene transcripts on drug efficacy and assessment of their selectivity for classes of compounds which act by the same mechanism, and identification of uncharacterized gene expression targets involved in cancer chemotherapy. Among them, the transcripts GC11121, GC17689, and GC18564 (unknown gene products extremely selective for RNA/DNA antimetabolites) are indicated by the present work as deserving high priority in future molecular studies.

Databases, Factual↗
PubMed2001

Proximal compared with distal gastric cancer: multivariate analysis of prognostic factors.

The major determinants of the poor prognosis of the patients with proximal-third gastric cancer (proximal gastric cancer or PGC) when compared with that of patients with more distally located gastric tumors (distal gastric cancer or DGC) rely both on the more advanced age and tumor stage at the moment of clinical presentation and on the higher postoperative mortality for PGC patients. We reviewed hospital records of 707 patients with gastric cancer (187 with PGC and 520 with DGC) observed during the period 1981 through 1996 at the same surgical unit. Demographic and pathological data, type of treatment, and hospital morbidity and mortality rates were recorded. Univariate and multivariate survival analysis was used to calculate the 5-year survival probabilities with respect to the following clinical and pathological variables: age, sex, gross appearance according to Borrmann classification, histological type according to Lauren, stage of the disease, tumor location, and type of treatment. PGC was associated with more advanced tumor stage (P < 0.0001), older age (P = 0.039), and higher necessity of extended surgery (P < 0.0001) when compared with DGC. Hospital mortality was 9.6 and 5 per cent in PGC and DGC patients respectively (P = 0.033). Overall 5-year survival was 17.7 and 36.4 per cent in PGC and DGC patients (P < 0.0001): 35.9 versus 57.6% (P = 0.0001) and 3.7 versus 7.6 per cent (P = 0.03) after radical and palliative surgery respectively. At multivariate survival analysis proximal location was found to be independently associated (P = 0.0007) with poor survival. The multivariate model shows the proximal location as an independent predictor of lesser favorable outcome in gastric cancer. The major determinants of the poor prognosis of PGC with respect to DGC rely both on the more advanced age and tumor stage at the moment of clinical presentation and on the higher postoperative morbidity for PGC patients.

Age Factors↗
PubMed1993

Mortality in pneumococcal meningitis: a multivariate analysis of prognostic factors.

OBJECTIVES: The mortality due to pneumococcal meningitis remains high, ranging from 15 to 60%. The purpose of this study was to analyze the prognosis of pneumococcal meningitis using a multivariate approach. The objectives were to select the most accurate initial mortality risk factors in pneumococcal meningitis and to determine an individual probability of death according to these prognostic factors. METHODS: The records of 105 consecutive cases of proven pneumococcal meningitis were retrospectively reviewed. The following parameters, recorded at presentation were considered for prognostic analysis: age, sex, duration of symptoms and antimicrobial chemotherapy before admission, underlying debilitating conditions, occurrence of seizures, pneumococcal bacteraemia or pneumonia, Glasgow coma scale score, Simplified Acute Physiological Score (SAPS), Cerebral Spinal Fluid (CSF) leucocyte count, CSF protein level, CSF glucose level and CSF/blood glucose ratio. Those parameters having a prognostic value after univariate logistic regression analysis were then entered into a multivariate stepwise logistic regression model. RESULTS: In multivariate analysis, a fatal outcome was best predicted by 4 variables. In descending order, these were the Glasgow coma scale score, age, CSF glucose level and concomitant pneumonia. The risk of dying was ten times higher in patients with Glasgow coma scale score < 7, seven times higher in patients older than 45 or having a CSF glucose level lower than 0.6 mmol/L and 4 times higher in patients with pneumonia. The logistic model provided an equation for the probability of dying that proved to have predictive values greater than 80% in determining the individual prognostic of pneumococcal meningitis. CONCLUSIONS: Our results are in agreement with most of previously published findings. We further demonstrated that the individual prognosis of pneumococcal meningitis could be accurately predicted with only 4 variables and highlighted the preeminent prognostic value of Glasgow coma scale score.

Adolescent↗