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Results for “Multivariate statistics”

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At least 109 records · Page 6Linked to original sources
PubMed1991

[Cytomorphological criteria of atypical hyperplasia and cancer of the endometrium based on data from a multivariate statistical analysis].

Multifactorial statistical analysis was used to identify differential diagnostic cytological features of glandular hyperplasia, atypical hyperplasia and well-differentiated adenocarcinoma of the endometrium. Twelve cytological features were identified for calculating linear discriminant function. The effectiveness of the diagnostic algorithm depends upon the diagnostic value of the sample and proficiency of the cytologist.

Adenocarcinoma↗
PubMedDate not supplied

Multivariate statistical analysis of bile cytology.

Cytologic features predictive of carcinoma in bile fluid were characterized by a review of 35 cases (22 malignant and 13 benign). Thirty-two cytologic variables were subjected to a stepwise multiple regression model to separate the criteria best suited to the benign versus malignant groups. Six key criteria were selected as useful indicators of malignancy: loss of honeycomb arrangement, enlarged nuclei, loss of polarity, bloody background, flat nuclei and cell-in-cell arrangement. Three or more of these criteria were observed in carcinoma cases more often than they were in noncancer cases (P < .01). By using these criteria, the overall sensitivity of diagnosing carcinoma by bile cytology was 86.4%, and the specificity was 76.9%.

Aged↗
PubMed1992

Simultaneous evaluation of genotoxicity data from different sources: a multivariate statistical approach.

A great deal of information on short-term mutagenicity assays presently exists, having been generated through individual as well as large comparative programs. The comparative programs have often examined the same tests, but with different sets of chemicals; this then gives rise to the problem of how to identify the information which is common to the different data bases, i.e., the general properties of the assays. This paper continues previous analyses of this subject, and describes a general approach by which different and heterogeneous data bases can be compared to each other. The results relative to 4 assays (Salmonella typhimurium gene mutation, mouse lymphoma L5178Y cell gene mutation, chromosomal aberrations in CHO cells, and SCEs in CHO cells) in 4 different data bases were studied. Factor analysis was used to model the different pieces of information. The analysis demonstrated a concordance between the indications of the U.S. National Toxicology Program and the International Program for the Evaluation of Short-Term Tests for Carcinogens, whereas the results of Gene-Tox and the International Program for Chemical Safety turned out to be biased, to different degrees, by their specific aims and characteristics. Moreover, the general properties--independent of the specific data bases--of the 4 assays were highlighted, and the similarities between the performances of the assays were given a quantitative measure.

Animals↗
PubMed1991

[Lactose--a potential dietary fiber. The regulation of its microecologic effect in the intestinal tract. 4. Dietary fiber action of lactose: evaluation with multivariate statistical analysis].

The conditions and the intestinal processes responsible for the action of lactose as a potential dietary fibre are described. The beta-galactosidase activity in the rat caecum and colon is influenced by dietary factors: It declines with increasing lactose concentration and it rises with increasing protein and phosphate concentration in the diet. The enzyme activity correlates negatively with the content of lactose, and positively with the content of protein and phosphate in the chymus. The products of lactose hydrolysis are degraded by microbial glycolysis in caecum and colon. The glycolytic products are mainly absorbed and energetically utilized by the macroorganism. Phosphate stimulates the microbial metabolism and, therefore, accelerates the consumption of the energy substrate lactose. Mathematical optimization gives the necessary composition of the diet which causes an intended microecological effect. To minimize the chymus pH (5.1 in the colon ascendens; 4.6 in the colon descendens; 4.3 in the faeces) the lactose content of the diet has to be greater than or equal to 160 mumol/g, the protein content less than or equal to 10 mg/g, and the phosphate content less than or equal to 5.5 mumol/g. The minimal pH value depends to a greater extent on variations in the supply of protein and phosphorus with the diet whereas the response to changes in lactose concentration is less noticeable.

Animals↗
PubMed1995

[Alpha blockers, TUS-P and TUR-P in the treatment of benign prostatic hypertrophy. A comparison using multivariate statistical analysis].

To evaluate the effectiveness of Alpha-blockers, TUI-P and TUR-P in the treatment of obstruction due to BPH, 50 patients, never before treated, were considered. Fifteen were treated with alfuzosin chlorhydrate 7.5 mg/day for four months, 15 were submitted to TUI-P and 20 to TUR-P. In all patients linear purr was carried out before treatment and was repeated from 60 to 90 days after intervention in surgical patients and during the fourth month of treatment in patients treated with alfuzosin. The data obtained were analyzed with the T-test both for dependent and independent samples. The results show that Alpha-blocker contain an increase in maximal flow, without decreasing bladder voiding pressures. On the contrary TUI-P and TUR-P, besides the increase in maximal flow obtain a significant reduction of bladder pressures. The conclusions are the following: maximal flow alone is not a sufficient parameter to evaluate the work of the bladder, the entity of the obstruction and the effectiveness of the therapy. The treatment with Alpha-blockers is unable to reduce the obstruction due to BPH. TUI-P and TUR-P realize an effective deobstruction. Under the same deobstructing effect TUR-P assures a better voiding performance by obtaining higher flow values.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Diagnostic effectiveness of serum bile acids in liver diseases as evaluated by multivariate statistical methods.

The aims of this study were to determine the diagnostic effectiveness of fasting and postprandial serum bile acid determinations in liver diseases, and to compare results with those of conventional liver function tests. In 322 patients with biopsy-proved liver disease and 93 healthy subjects, fasting and postprandial (2 hr) serum levels of cholic, chenodeoxycholic, and lithocholic acid conjugates and conventional liver function tests were evaluated. Data were subjected to variance and discriminant and factor analyses. Fasting serum bile acids were higher in patients when compared to controls and were significantly higher in severe than in mild liver diseases. Determination of cholic plus lithocholic acid provided the highest discrimination capacity. The percent of correct allocation was 75.4% for conventional liver function tests, 70.1% for fasting serum bile acids and increased to 79.6% when liver function tests plus serum bile acids were considered. Postprandial percentages were always lower than fasting. Factor analysis identified two factors possibly related to cytolysis and protein synthesis. The serum bile acid concentrations highly correlated with both factors. We conclude that serum bile acid determinations increase the diagnostic and discriminant capacities of liver function tests and are more sensitive and discriminant when obtained in fasting than postprandially.

Adult↗