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Results for “multivariate analysis”

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PubMed2005

Estuarial fingerprinting through multidimensional fluorescence and multivariate analysis.

As part of a strategy for preventing the introduction of aquatic nuisance species (ANS) to U.S. estuaries, ballast water exchange (BWE) regulations have been imposed. Enforcing these regulations requires a reliable method for determining the port of origin of water in the ballast tanks of ships entering U.S. waters. This study shows that a three-dimensional fluorescence fingerprinting technique, excitation emission matrix (EEM) spectroscopy, holds great promise as a ballast water analysis tool. In our technique, EEMs are analyzed by multivariate classification and curve resolution methods, such as N-way partial least squares Regression-discriminant analysis (NPLS-DA) and parallel factor analysis (PARAFAC). We demonstrate that classification techniques can be used to discriminate among sampling sites less than 10 miles apart, encompassing Boston Harbor and two tributaries in the Mystic River Watershed. To our knowledge, this work is the first to use multivariate analysis to classify water as to location of origin. Furthermore, it is shown that curve resolution can show seasonal features within the multidimensional fluorescence data sets, which correlate with difficulty in classification.

Classification↗

PubMed1991

Isolated coronary artery bypass grafting in one hundred consecutive octogenarian patients. A multivariate analysis.

One hundred consecutive patients aged 80 or older underwent isolated coronary artery bypass grafting for New York Heart Association functional class III (24%) or IV (76%) disease in our institution from 1985 to 1989. The operations were elective in 36 patients, urgent in 52, and emergent in 12. Twenty-eight patients had significant disease of the left main coronary artery, with the remainder having an average of 2.8 diseased coronary vessels. Preoperative left ventricular ejection fraction was considered good (greater than 50%) in 62 patients, fair (30% to 50%) in 24 patients, and poor (less than 30%) in 14 patients. An average of 2.8 grafts were performed per patient, and the internal mammary artery was used in 10 patients. Univariate analysis of 36 perioperative factors followed by multivariate logistic regression analysis of the significant variables (p less than 0.05) revealed that the urgency of the operation and left ventricular ejection fraction were independent predictors of operative mortality. There were 12 in-hospital deaths, and the mortality was significantly lower in the elective cases (2.8%) than in the urgent (13.5%) and emergent cases (33.3%). Major complications occurred in 14% of the elective cases, in 21% of the urgent cases, and in 67% of the emergent cases. The operative mortality rates for good, fair, and poor left ventricular ejection fraction were 4.9%, 12.5%, and 42.9%, respectively. Long-term follow-up averaging 22 months revealed a 77% actuarial probability of survival at 24 months and 51% at 48 months, with only two cardiac-related deaths. We conclude that coronary artery bypass grafting can be performed in octogenarians with a favorable outcome when done electively in patients with normal to moderately depressed left ventricular function.

Aged↗

PubMed2001

Heavy metal contents in the Delft canal sediments and suspended solids of the River Rhine: multivariate analysis for source tracing.

We have analyzed heavy metal contents in the sediments of three Delft inner city canals (Rietveld, Oude Delft and Zuiderstraat) and compared them with the heavy metal contents in the River Rhine suspended solids. All the data were examined by multivariate analysis in order to explain the behavior and sources of each metal. Correlation coefficient matrices were studied in order to find an internal structure and assist in identification of pollutant sources. The good correlation among almost all the heavy metals (except Pb) indicates that there are common sources or at least one major source for them. Based on the factor analysis technique, principal components score plots were obtained to cluster the data (63 samples from the Delft canals and 10 from the River Rhine) and describe their different characteristics. It was found in the plots that the data from the River Rhine clustered together with 2 out of the 3 Delft stations (Rietveld, Oude Delft). This supports the view that the River Rhine is an important external micropollutant source for the Delft inner city canals. The third station (Zuiderstraat) showed much higher pollution levels than the other Delft canals; apparently it has been influenced not only by the River Rhine but also by internal pollutant inputs such as metal corrosion and paints from local boathouses.

Cities↗

PubMed2004

Prediction of success rate after extracorporeal shock-wave lithotripsy of renal stones--a multivariate analysis model.

OBJECTIVES: To define prognostic factors that affect the success rate after extracorporeal shock-wave lithotripsy (ESWL) of renal calculi and to estimate the probability of stone-free status using a regression analysis model. MATERIAL AND METHODS: Between February 1992 and February 2002, 2954 patients with single or multiple radiopaque renal stones (<30 mm) underwent ESWL monotherapy. The results of treatment were evaluated after 3 months of follow-up. Treatment success was defined as complete clearance of the stones with no residual fragments. The stone-free rate was correlated with stone features and patient characteristics using the chi2 test. Factors found to be significant using the chi2 test were further analyzed using multivariate regression analysis. RESULTS: At 3-month follow-up, the overall stone-free rate using ESWL monotherapy was 86.7%. Failure to disintegrate the stones was observed in 7.3% of cases (n = 216) and failure to clear the fragmented stones occurred in 6% (n = 177). Repeat ESWL was needed in 53% of cases. Static steinstrasse occurred in 4.9% of cases (n = 146) and post-ESWL auxiliary procedures were required in 4% (n = 118). Using the chi2 test, patient age (p < 0.001), stone size (p < 0.001), location (p < 0.001), number (p < 0.001) and nature (p = 0.003), radiological renal picture (p < 0.001) and congenital renal anomalies (p < 0.001) had a significant impact on the stone-free rate. Multivariate analysis excluded stone nature from the logistic regression model while other factors maintained their statistically significant effect on success rate, indicating that they were independent predictors. A regression analysis model was designed to estimate the probability of stone-free status after ESWL. The sensitivity of the model was 83%, the specificity 91% and the overall accuracy 87%. CONCLUSION: Patient age, stone size, location and number, radiological renal features and congenital renal anomalies are prognostic factors determining stone clearance after ESWL of renal calculi. Our regression model can predict the probability of the success of ESWL with an accuracy of 87%.

Adolescent↗

PubMed1989

Multivariate analysis of prognostic factors in patients with advanced prostatic cancer: results from 2 European Organization for Research on Treatment of Cancer trials.

The European Organization for Research on Treatment of Cancer Genitourinary Group performed a multivariate statistical analysis of prognostic factors based on 436 patients entered between 1976 and 1981 in 2 randomized prospective trials that compared 4 different hormonal treatment regimens. Only previously untreated patients with advanced (stage T3/T4/M0 or M1) prostatic cancer were eligible. After identification of prognostic factors by means of univariate analyses a multivariate analysis using Cox's proportional hazards regression model was done. This test identified performance status (according to the Eastern Cooperative Oncology Group scale) as the most important factor, followed by acid phosphatase (more than 2 times normal) for stage M0 cancer patients, and alkaline phosphatase, T category and the presence or absence of associated chronic disease for stage M1 cancer patients. Based on these 4 variables nonbedridden patients with metastatic disease can be divided into 2 groups: poor and good risk patients, with median survivals of 1 and 3 years, respectively. This study shows that routine clinical and laboratory data already provide an excellent indication as to the prognosis.

Adult↗

PubMed1983

Multivariate analysis of urinary RNA catabolites in malignancies: cross-sectional and longitudinal studies.

Urinary RNA catabolites, especially modified nucleosides and nucleobases, have turned out to represent valuable new criteria for diagnosis and follow-up of malignancies. Here we show for the first time that multivariate analysis of urinary RNA catabolites can distinguish between tumor carriers and controls who, if examined by univariate procedures, would remain undifferentiated. Two such models have been demonstrated. We hope that a continuation of this work will support primary clinical diagnostic procedures, the control of therapy effects, and the long-term follow-up of patients, which should be regarded as special medical applications of the general principles of molecular biology.

Analysis of Variance↗

PubMed1999

Prognostic value of p53 protein expression for patients with gastric cancer--a multivariate analysis.

Mutations in the p53 gene, one of the most common genetic alterations in human cancer, are implicated in tumorigenesis and tumour progression. Although p53 protein expression appears to be correlated to prognosis in patients with malignancy, its prognostic role in gastric cancer has remained controversial. We examined the clinical significance of p53 overexpression in 427 patients with gastric cancer, using multivariate analysis. Tumour sections of gastric cancer tissues from these 427 Japanese patients were stained immunohistochemically with monoclonal antibody PAb1801. The presence of p53 expression was statistically compared with clinicopathological features and post-operative survival, using univariate and multivariate analyses. p53 expression was detected in 38.6% (165 out of 427) of these gastric cancers and immunoreactivity was not observed in normal mucosa adjacent to the tumour. A higher rate of p53 detection was observed among large tumours and in those with a prominent depth of invasion, lymphatic and vascular invasion and lymph node involvement. Prognosis was significantly worse for patients with p53-positive-staining tumours. The 5-year survival rate was 62.5% for patients with p53-negative tumours and 43.3% for those with positive malignancies. p53 expression was a significant prognostic factor for node-positive gastric cancers in subjects undergoing treatment with curative resection, as assessed by Cox regression analysis. Thus, the expression of p53 was closely related to the potential for tumour advance and a poorer post-operative prognosis for patients with gastric cancer.

Analysis of Variance↗

PubMed1985

Prognostic factors in children with acute lymphoblastic leukemia. Part II: Multivariate analysis. Children's Cancer and Leukemia Study Group.

The pretreatment characteristics of 158 children with previously untreated acute lymphoblastic leukemia diagnosed April 1972 to June 1978 were analyzed for their ability to predict prognosis. The children were treated according to therapeutic protocols 721, 745 and 765, by members of the Japanese Children's Cancer and Leukemia Study Group. Multivariate analysis was performed to determined the relationship between the characteristics and duration of survival of the patients. The following characteristics were analyzed: initial white blood cell (WBC) count, age at diagnosis, initial hemoglobin level, initial platelet count, sex, organomegaly, and treatment regimen that was provided. By using multivariate techniques, factors were found which the independently and significantly predict the length of survival. These factors were initial WBC count (r0 = 0.2908), age at diagnosis (r0 = 0.2982), and treatment regimen (r0 = 0.2488). Using the major prognostic factors of age at diagnosis and initial WBC count, a formula to predict the survival time was established. According to the initial WBC count and age at diagnosis, we classified all cases of childhood ALL as standard risk and high risk.

Adolescent↗

PubMed1984

A multivariate analysis of factors affecting wound-healing time.

For post-Mohs surgical defects of the head and neck, the width of the defect is the best predictor of the length of that time it will take the wound to heal. This conclusion is based on a multivariate analysis, testing the effect of the following factors on wound-healing time: (1) age, (2) sex, (3) sound location, (4) wound width, (5) wound length, and (6) wound length X wound width. After accounting for wound width, none of the other factors significantly influenced the rate of wound healing. The 64 wounds evaluated were dressed daily with one of five bandages. When compared with the controls, and after correcting for wound width, each of the test bandages shortened wound-healing time. Among the treatment groups, no significant differences were found in the cultures or in the appearance of the wounds.

Aged↗

PubMed1989

Mortality in pediatric paratesticular rhabdomyosarcoma: a multivariate analysis.

We performed a retrospective analysis of 28 children presenting with confirmed paratesticular embryonal rhabdomyosarcoma to examine factors predictive of fatal outcome. Complete surgery, defined as radical inguinal orchiectomy with clear microscopic margins plus radical, retroperitoneal lymph node dissection with extirpation of all gross disease, was performed in 21 patients (75 per cent). All patients received chemotherapy and 20 received radiation therapy according to protocol. Of the patients 16 have survived for more than 5 years with no evidence of disease. Univariate analysis revealed that only the presence of parenchymal metastases at diagnosis (p less than or equal to 0.040) and unresectability (p less than or equal to 0.003) were significant predictors of fatal outcome. Multivariate analysis showed that unresectability was the most important predictor of mortality with an estimated relative risk of 5.8.

Adolescent↗

PubMed2004

Multivariate analysis of biochemical markers in synovial fluid from the shoulder joint for diagnosis of rotator cuff tears.

Multivariate discriminant analysis allowed definition of cytokine, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) levels in synovial fluid (SF) of patients with rotator cuff tears and other shoulder lesions. We analyzed SF aspirated from the glenohumeral joints of 17 patients with rotator cuff tears; SF from nine patients with other shoulder lesions was used to characterize a non-rotator-cuff-tear (NRCT) group. Discriminant analysis demonstrated statistically significant differences in (1) the determination of whether rotator cuff tear patients are separable from the NRCT group using the influential functions, the most influential of which were interleukin 1-beta, MMP-2, and MMP-13, and (2) the assessment of whether full-thickness rotator cuff tears are distinguishable from partial tears using identical influential functions. The most influential function in the latter analysis was MMP-13. Both interleukin 1-beta and MMP-13 might be biochemical markers of impending rotator cuff tears.

Adolescent↗

PubMed1989

Acute cholangitis. Multivariate analysis of risk factors.

In order to identify risk factors in patients with acute cholangitis, 140 clinical, biochemical, etiologic, and pathologic variables of 449 attacks of acute cholangitis seen in one center over a 20-year period were analyzed. Simple regression revealed 24 factors with prognostic significance, but multivariate analysis detected only seven factors with independent significance in predicting mortality (acute renal failure, cholangitis associated with liver abscesses or liver cirrhosis, cholangitis secondary to high malignant biliary strictures or after percutaneous transhepatic cholangiography, female gender, and age). When the presence of each of these factors is weighted proportional to its coefficient of regression, patients with cholangitis could be scored on a scale of 0-27. A score of seven was clinically the most useful cut off--388 attacks of cholangitis associated with a score of less than 7 had a mortality rate of only 1.8%, whereas 61 attacks associated with a score greater than or equal to 7 had a mortality rate of 49%. The value of this scoring system needs to be confirmed in prospective studies, but it may prove useful, for example, in selecting a group of high-risk patients for urgent biliary decompression in an attempt to reduce the mortality associated with this pathology.

Acute Disease↗

PubMed1991

Multivariate analysis of factors associated with calving interval and calving rate in dairy cows.

We collected data on reproductive events of cows (n = 2116) that included dates of calving, first service, last artificial insemination before pregnancy examination, pregnancy examination, abortion, diagnosis of cystic ovary, and treatment with prostaglandin. We used multivariate analysis to evaluate the relationship between the interval from insemination to pregnancy examination and the length of calving interval, adjusting for other factors affecting the calving interval. The effect of the interval from insemination to pregnancy examination on calving rate was estimated using logistic regression analysis. The calving interval was long for cows with a short interval from artificial insemination to first pregnancy examination, it was at a minimum at 55 d and increased thereafter. Other factors affecting the calving interval were cystic ovaries, prostaglandin treatment, abortion, number of artificial inseminations, and days to first service. The calving rate was low among cows with a short interval to pregnancy examination, reached a maximum at 48 d, and then declined. Other factors affecting the calving rate were abortion, number of artificial inseminations and whether the cow was bred by a clean-up bull.

Journal Article↗

PubMed1984

A multivariate analysis of the risk indicators of reduction limb defects.

In order to evaluate associations of various selected risk indicators with reduction limb defects, data on 453 cases of reduction limb defects and their time-area matched pair controls from the Finnish Registry of Congenital Malformations was studied. A multivariate analysis of the earlier reported associations was performed. This analysis showed that the following risk indicators were associated with the defects: high birth order, threatened abortion, low placental weight, low birth weight, previous malformations in the family, influenza during early pregnancy, other infectious diseases, and mother's alcohol consumption during pregnancy.

Abortion, Threatened↗

PubMed2002

[Effectiveness of neck dissection in metastasizing mouth carcinoma. Uni- and multivariate analysis of factors of influence].

BACKGROUND: The purpose of this study was to evaluate the oncologic effectiveness of radical and different types of modified neck dissections with preservation of n. accessorius, v. jugularis interna, and m. sternocleidomastoideus and to identify prognostic factors for regional control and survival in univariate and multivariate analysis. METHODS: This retrospective study included 373 patients with squamous cell carcinoma of the oral cavity who underwent 401 neck dissections between January 1986 and December 1995 at the Department for Oral and Maxillofacial Surgery, Hanover Medical School. RESULTS: The 5-year regional control was estimated at 87%. Relapse occurred only within the first 2 years after neck dissection. The number of positive nodes, metastases without lymphatic tissue, preparation of metastases from the carotid artery and cranial base, and preoperative radiochemotherapy were analyzed as prognostic factors with significant influence. The grade of metastases, extracapsular spread, lymphangiosis carcinomatosa, and postoperative radiation showed no prognostic significance. DISCUSSION: The comparison of recurrent metastases after radical and modified neck dissection demonstrated that as the extent of neck disease increased there was a tendency toward improved regional control after radical neck dissection.

Adult↗

PubMed1985

Multivariate analysis of glycosylated haemoglobin in insulin-treated diabetics.

Glycosylated haemoglobin (HbA1), as an assessment of overall control, was estimated in 858 insulin-treated diabetics attending for changeover to U100 insulin in North East Wales. Details of age, sex, duration of diabetes, insulin regimen and monitoring method were recorded. Multivariate analysis revealed lower HbA1 in patients receiving twice-daily (mean 11.01) as compared with once-daily insulin (11.42, P = 0.011), but no difference was found between urine and blood glucose testers when other variables were taken into consideration. HbA1 was lower in men (mean 10.94) compared with women (mean 11.39, P = 0.004) and there was a positive correlation of HbA1 in men with age (P = 0.046) and in women with duration of disease (P = 0.005).

Age Factors↗

PubMed1989

Factors determining sodium chloride sensitivity of patients with essential hypertension: evaluation by multivariate analysis.

Factors which determine sodium chloride sensitivity, defined as the difference between the mean blood pressure after 1 week of a low sodium chloride diet (3 g/day) and that after 1 week of a high sodium chloride diet (20 g/day), were studied in 60 inpatients with essential hypertension using a multivariate analysis. The sodium chloride sensitivity was independently correlated with the change in erythrocyte sodium concentration (r = 0.47) and with the change in plasma renin activity (r = 0.29); but it was not related to basal blood pressure, the change in plasma volume of the change in plasma norepinephrine concentration. These data suggest that both intracellular sodium accumulation and inadequate suppression of the renin-angiotensin system may be independently involved in the elevation of blood pressure after sodium chloride loading. We could not find the independent importance of volume retention, hyperadrenergic activity or basal blood pressure in the sodium chloride sensitivity.

Blood Pressure↗

PubMed1993

[Multivariate analysis of clinical signs, parameters of anorectal manometry, defecography, transit time of radiopaque markers in 76 patients complaining of fecal incontinence].

The aim of this study was to evaluate clinical symptoms, disease past-history, and parameters of anorectal manometry, defecography, and radiopaque pellet transit time in anal incontinence by multivariate analysis. We studied 76 patients, 68 women and 8 men, who complained of anal incontinence, excluding that due to obstetrical lesions. All patients were asked to complete a standard questionnaire. Results indicated that: a) hemorrhoidectomy, hysterectomy, and cholecystectomy appeared to play a role, b) daily incontinence for air or liquid stools is more frequent after hemorrhoidectomy, c) decreased resting pressure of the upper part of the anal canal was observed mainly after hysterectomy, d) decreased resting pressure of the upper part of the anal canal could be a factor of poor prognosis after treatment, e) anal incontinence in men was secondary to traumatic lesions of the anal sphincter in 7 of 8 cases.

Adult↗