A multivariate approach in statistical analysis for perinatal research: Cox regression analysis.
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Biomedical subjects
Publications and source records attributed to A Farina.
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Stage grouping is a method of summarizing multiple categories generated from the tumor, node, metastasis (TNM) classification system. Recently three different systems, the T and N integer score (TANIS), Hart, and 1997 Union Internationale Contre le Cancer systems, have been proposed. To verify their correlation to survival, a series of 64 patients affected by primary squamous cell carcinoma of the oropharynx was considered in this retrospective study. The data set was classified according to Union Internationale Contre le Cancer T stage and then grouped as recommended by the three systems. Results showed a crude survival rate of 28.13%. Univariate analysis by means of the logrank test yielded significant P values for the T and N integer score and Hart systems (0.0452 and 0.0179, respectively) and a borderline P value (0.0728) for the stratification based on the 1997 Union Internationale Contre le Cancer system. Multivariate analysis (Cox regression adjusted for age and sex) showed a significant correlation between the three staging systems and the mortality rate. Odds ratios were 1.36 (95% confidence interval, 1.12-1.66), 1.58 (95% confidence interval, 1.18-2.12), and 1.63 (95% confidence interval, 1.08-2.48) for the T and N integer score, Hart, and 1997 Union Internationale Contre le Cancer systems, respectively. The T and N integer score system showed the best statistical correlation, but a conclusive result could not be achieved because of the low number of patients in this study.
OBJECTIVE: The aim of this pictorial essay is to describe the sonographic guided approach to investigation and local injection therapy of a small joint in a patient with psoriatic arthritis (PA). METHODS: Sonographic pictures are obtained using a high frequency ultrasonography apparatus equipped with a 13-MHz transducer. RESULTS: Ultrasonography allows a careful morphostructural assessment of soft tissue involvement in PA patients. Sonographic findings include joint cavity widening, capsular thickening, synovial proliferation, synovial fluid changes, tendon sheath widening. Ultrasound guided placement of the needle within the joint and injection of corticosteroid under sonographic control can be easily performed. CONCLUSIONS: High frequency ultrasonography is a quick and safe procedure that allows a useful diagnostic and therapeutic approach in patients with arthritis of small joints.
In a cross-sectional study, the intrauterine growth pattern of 32 twins was compared to that of 205 singletons by analysis of the coefficients of the equations of biparietal diameter (BPD), femur length (FL) and abdominal circumference (AC). Lower values were observed in twins from the 20th week. BPD and AC curves showed a progressively diverging pattern, and yielded different coefficients of equations. AC showed the highest discriminant capacity followed by BPD and FL. Combined values of the two series solved by discriminant function output produced an overlapping of 58%. Based on our data, nomograms of growth of singletons should not be used for twins.
In 1997, the U.I.C.C. (International Union against Cancer) modified the previous TNM stage grouping published in 1987. In the present study, TANIS and TNM '97 systems were compared in order to evaluate their prognostic ability. Data from 164 patients affected by primary squamous cell carcinoma cancers of the oral cavity (n=100) and oropharynx (n=64) were analyzed by means of survival analyses. Both systems showed a significant correlation with survival rate. TANIS yielded better results in association with the survival rate as compared with TNM '97.
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Halogen bonds, attractive intermolecular interactions between perfluoroalkyl bromides and bromide ions, are present in cocrystals of (-)-sparteinium hydrobromide (1) and (S)-1,2-dibromohexafluoropropane (2; shown schematically), and result in enantiopure and infinite supramolecular helices. The perfluorocarbon-hydrocarbon self-assembly allows the resolution of racemic 2.
The aim of the present study was to generate different latent variables that classify the major chromosome aneuploidies using frequency and patterns of fetal sonographic abnormalities in a large database. A total of 1867 fetuses with sonographic abnormalities recorded in a database at New England Medical Center from January 1995 to March 1998 were available for the statistical analysis. Included within this group were 61 aneuploid fetuses, including 11 with 45,X, 30 with trisomy 21, 14 with trisomy 18 and 6 with trisomy 13, 40 structural malformations and/or sonographic markers were detected in these 61 aneuploid fetuses. The ability of malformations and sonographic markers to generate different groups of phenotypes was evaluated by means of latent class analysis, using the 61 affected cases. Four different classes were generated with the hypothetical assumption that each of them could satisfactorily identify a respective fetal aneuploidy represented in the study group. Among 40 fetal malformations and/or sonographic markers, the most important findings in generating specific karyotypic groups were cystic hygroma (class 1), duodenal atresia (class 2), holoprosencephaly (class 3) and omphalocele (class 4), respectively. Accuracy of the classification was 72 per cent for Turner syndrome (class 1), 74 per cent for Down syndrome (classes 1 and 2), 88 per cent for trisomy 13 (class 3) and 93 per cent for trisomy 18. The frequency of associated malformations detected sonographically can help to define a phenotype that is likely to be representative of a specific aneuploidy. Before the definitive karyotype is available or, in cases in which patients refuse an invasive prenatal diagnostic procedure, this may improve antenatal clinical management.
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Explore the source record for details and available documents.
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We report a retrospective study of 64 patients with primary squamous cell carcinoma of the oropharynx. The tumours were classified by the UICC (Union Internationale Contre le Cancer) system and a New Tumour Staging (NTS) system. Results showed a crude survival of 29% at 5 years. The most important prognostic factor for survival rate was the tumour (T) stage in both classifications. NTS recommendations that consider the number of sites and subsites involved yield a better correlation between survival and T stage. NTS also discriminates better between the T stages than the UICC criteria.
PURPOSE: The 1987 TNM classification system modified some T and N definition but it did not change stage grouping. Consequently it has not improved the prognostic validity of the advanced stage groups. In 1993, a new stage grouping was purposed, TANIS, that seems to have a higher correlation with survival. In this report, the TNM classification and TANIS system were compared to evaluate this prognostic ability. PATIENTS AND METHODS: Data from 164 patients affected by primary cancers of oropharynx or oral cavity were analyzed by means of Kaplan-Meier and Cox regression analysis. RESULTS: The crude survival rate at 5 years was 43.9%. Both systems showed a significant correlation with the survival rate by means of Cox regression analysis. TANIS subcategories were correlated to the mortality rate in the stage IV patients. TANIS resulted a better predictor of mortality when compared with TNM. CONCLUSION: The TANIS system was able to separate the TNM stage IV patients into prognostic groups, yielding more information with respect to TNM for such a category of patients. When a comparison between TNM and TANIS was performed, it was observed that TANIS had a higher correlation with survival rate, whereas TNM did not add any information in defining the survival function.
Human alpha1-acid glycoprotein (alpha1-AGP) has been used as a chiral stationary phase (CSP) for the enantioseparation of midodrine and deglymidodrine racemates in the same HPLC run. The imobilized AGP resulted as the best chiral selector for the enantioresolution of two compounds. Due to the modification of alpha1-AGP characters as a result of changing the composition of the mobile phase, an attempt study of the watery mobile phase (ionic strength and pH of the buffer, nature and concentration of the organic modifier) allowed for an increase in the enantioselectivity of the chromatographic system and an optimization of the resolution base-line of both enantiomeric pairs.
A micellar electrokinetic chromatographic method for the separation and quantification of ceftazidime, its delta2-isomer and pyridine (two ceftazidime related impurities) was developed and validated. Optimised conditions were obtained using an electrolyte system consisting of 25 mM sodium tetraborate, at pH 9.2, and 75 mM sodium dodecylsulphate. A limit of detection of 0.2 microg ml(-1) and a limit of quantitation of 0.6 microg ml(-1) were estimated for pyridine and delta2-isomer: this means that levels of < 0.1% of pyridine and delta2-isomer in ceftazidime can be determined. Calibration curves for all analytes were linear over the studied ranges with correlation coefficients >0.999. Good reproducibility for migration times and corrected peak areas were achieved (RSD % 0.3 and 1.0, respectively). The results demonstrate that the method is reproducible, accurate and appropriate for ceftazidime assay in pharmaceutical samples.
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