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PubMed1994

A retrospective analysis of bone scan abnormalities in mastocytosis: correlation with disease category and prognosis.

UNLABELLED: To investigate the usefulness of bone scintigraphy in systemic mastocytosis (SM), the scans of 73 patients were retrospectively reviewed and correlated with disease category. METHODS: A modification of a previously described method for bone scan classification in this disease was used. In addition to the group as a whole, two subsets of patients with multiple bone scans were identified for closer analysis: those with (n = 13) and without (n = 12) scintigraphic evidence of progression of disease. RESULTS: Overall, patients with more aggressive SM tended to have increasingly abnormal initial bone scans (p2 = 0.0003), although there was a considerable degree of overlap. Of patients undergoing serial studies, those with scintigraphic progression also tended to have more aggressive disease (p2 = 0.006) and a poorer prognosis than those with stable bone scans. CONCLUSIONS: Both the degree of abnormality on initial bone scan and progression of scintigraphic abnormalities with serial scanning appear to correlate with the presence of more aggressive systemic mastocytosis. Based on the patterns seen, in many cases this may be a reflection of bone marrow expansion, which in turn probably reflects increased marrow disease.

Adolescent↗

PubMed2000

Nonhistological diagnosis of human cerebral tumors by 1H magnetic resonance spectroscopy and amino acid analysis.

We describe a multivariate analysis procedure to classify human cerebral tumors nonhistologically in vitro, combining the use of 1H magnetic resonance spectroscopy (MRS) with automatic amino acid analysis of biopsy extracts. Eighty-one biopsies were obtained surgically and classified histologically in eight classes: high-grade astrocytomas (class 1, n = 19), low-grade astrocytomas (class 2, n = 10), normal brain (class 3, n = 9), medulloblastomas (class 4, n = 4), meningiomas (class 5, n = 18), metastases (class 6, n = 8), neurinomas (class 7, n = 9), and oligodendrogliomas (class 8, n = 4). Perchloric acid extracts were prepared from every biopsy and analyzed by high resolution 1H MRS and automatic amino acid analysis by ionic exchange chromatography. Intensities of 27 resonances and ratios of resonances were measured in the 1H MRS spectra, and 17 amino acid concentrations were determined in the chromatograms. Linear discriminant analysis provided the most adequate combination of these variables for binary classifications of a biopsy between any two possible classes and in multiple choice comparisons, involving the eight possible classes considered. Correct diagnosis was obtained when the class selected by the computer matched the histological diagnosis. In binary comparisons, consideration of the amino acid profile increased the percentage of correct classifications, being always higher than 75% and reaching 100% in many cases. In multilateral comparisons, scores were: high-grade astrocytomas, 80%; low-grade astrocytomas, 74%; normal brain, 100%; medulloblastomas, 100%; meningiomas, 94.5%; metastases, 86%; neurinomas, 100%; and oligodendrogliomas, 75%. These results indicate that statistical multivariate procedures, combining 1H MRS and amino acid analysis of tissue extracts, provide a valuable classifier for the nonhistological diagnosis of biopsies from brain tumors in vitro.

Algorithms↗

PubMed2002

Interobserver reliability in the interpretation of radiologic signs in Legg-Calvé-Perthes disease.

An accurate interpretation of radiographs is crucial in determining therapeutic choices in Legg-Calvé-Perthes disease. The aim of this study was to measure the interobserver reliability of a group of surgeons in this condition. Twenty-three radiographs were shown to nine pediatric orthopedic surgeons at nine different medical centers. Differences in coding between members of the group was assessed using a two-way random factor analysis of variance. Reliability was excellent for the Catterall classification [intraclass correlation coefficient (ICC) = 0.94], and good for the stage of disease and Head at Risk signs (ICC ranging from 0.74 to 0.85) except for lateral subluxation, whose reliability is fair (ICC = 0.68). Analysis of results shows that lateral subluxation should be expressed in a quantitative measurement rather than a binary answer. The reliability of Gage's sign would be improved if multiple definitions did not exist in the literature. In experienced hands, Catterall's classification can be used with reliability. Difficulties are still noted in separating group II frorm group III.

Child↗

PubMed1985

Statistical age-period-cohort analysis: a review and critique.

Descriptive and statistical age-period-cohort (APC) analysis methods have received considerable attention in the literature. The statistical modeling of APC data often involves the popular multiple classification model, a model containing the effects of age groups (rows), periods of observation (columns), and birth cohorts (diagonals of the age-by-period table). The identifiability problem inherent to this model is discussed, and its adverse effects on the results of APC modeling exercises are illustrated numerically. Potential problems attendant with the use of two-factor models are described, and other possible modeling approaches currently in use are discussed. Interpretational limitations due to certain innate characteristics of typical APC data sets are also detailed. Given all the documented potential sources for error, the current state-of-the-art regarding the statistical modeling of APC data should be considered to be at an early stage of development.

Adult↗

PubMed2003

The Maternal Phenylketonuria International Study: 1984-2002.

OBJECTIVE: The purpose of this report is to review the obstetric medical, psychological, and nutritional aspects and outcome of the women and offspring enrolled in the Maternal Phenylketonuria Study, which was established to assess the efficacy of a phenylalanine (Phe)-restricted diet in preventing the morbidity associated with this disorder. METHODS: A total of 382 women with hyperphenylalaninemia (HPA) were enrolled in the study and completed 572 pregnancies. Outcome measures were analyzed with chi2, Fisher exact text, analysis of variance, t test, Wilcoxon nonparametric test, and multiple logistic regression. Outcome measures were stratified according to maternal HPA classification and the time when dietary control was achieved. RESULTS: Optimal birth outcomes occurred when maternal blood Phe levels between 120 and 360 micromol/L were achieved by 8 to 10 weeks of gestation and maintained throughout pregnancy (trimester averages of 600 micromol/L). Mothers with mild HPA achieved similar birth outcomes as mothers who were in control preconceptually and those in control by 8 to 10 weeks of pregnancy. CONCLUSIONS: Before conception, counseling and early entrance into a prenatal care program is essential in achieving optimal fetal outcome in women with HPA. The achievement of pre- and periconceptional dietary control with a Phe-restricted diet significantly decreased morbidity in the offspring of women with HPA.

Analysis of Variance↗

PubMed2005

The Irish Affected Sib Pair Study of Alcohol Dependence: study methodology and validation of diagnosis by interview and family history.

BACKGROUND: This article is the first report of the Irish Affected Sib Pair Study of Alcohol Dependence, whose goal is to detect the genomic location of susceptibility loci for alcohol dependence (AD). This article describes phenotypic characteristics of the probands, siblings, and parents included in the sample and examines agreement among different sources of diagnostic information, including the validity of family history (FH) assessment. METHODS: Structured diagnostic interviews were conducted with 1414 individuals from 591 families ascertained in Ireland. AD was assessed among 1201 probands and affected siblings with use of the Semi-Structured Assessment for the Genetics of Alcoholism and among 213 parents with use of a modified version of the Structured Clinical Interview for DSM. Probands and siblings were also assessed for drinking history, comorbid disorders, and other clinical characteristics. FH reports based on FH-Research Diagnostic Criteria were obtained for 1113 of these individuals as well as for 3652 first-degree relatives who were not interviewed. RESULTS: Sample characteristics confirm the severity of AD among the affected individuals. Agreement between FH ratings and diagnoses based on direct interviews was high for both parent-offspring and sibling-sibling comparisons (e.g., positive and negative predictive values > 80% for a range of cutoffs). Agreement among individuals about their family members was also high for a single item (1 month or more of drinking problems, tetrachoric r = 0.86-0.98), the total number of DSM-IV AD symptoms (polychoric r = 0.86-0.96), and classifications based on a range of cutoffs (kappa = 0.75-0.80). Use of multiple informants improved classification accuracy only slightly (6-10%). CONCLUSIONS: The authors successfully collected data for a large sample of affected sibling pairs for molecular genetic analysis of AD. Individuals with AD were able to provide accurate evaluations of alcoholism symptoms in their parents and adult siblings. A single screening item performed nearly as well as the full scale. Collecting information from multiple informants may not be cost effective for the gain in predictive accuracy. FH information collected from affected informants can be a valuable source of diagnostic information for family studies of alcoholism.

Adult↗

PubMed1986

Applications of computerized interactive morphometry in pathology. II. A model for computer generated diagnosis.

We present a model for the analysis and tentative diagnosis of pathologic problems by a trained observer utilizing data generated by a video based computerized interactive morphometry system in conjunction with multivariate methods of discriminant classificatory analysis that separate classes based on unweighted numerical values and with adhoc algorithms based on hierarchical analysis. The model was tested with two diagnostic problems that could benefit from a morphometric approach: the classification of non-Hodgkin's lymphomas from routine histologic slides and the distinction of malignant mesotheliomas from benign effusions in smears prepared from pleural effusions. The touch-sensitive screen of the computerized interactive morphometry system enables trained observers to measure the real time image of profiles of interest either by using graphic standards or simply by touching the two extreme points of the diameter of interest. This procedure generates multiple data in the form of classes that can be effectively used toward the more objective discrimination of lesions of difficult classification by analysis with a combination of adhoc diagnostic algorithms and multivariate statistical methods.

Computers↗

PubMed2003

GARBAN: genomic analysis and rapid biological annotation of cDNA microarray and proteomic data.

SUMMARY: Genomic Analysis and Rapid Biological ANnotation (GARBAN) is a new tool that provides an integrated framework to analyze simultaneously and compare multiple data sets derived from microarray or proteomic experiments. It carries out automated classifications of genes or proteins according to the criteria of the Gene Ontology Consortium at a level of depth defined by the user. Additionally, it performs clustering analysis of all sets based on functional categories or on differential expression levels. GARBAN also provides graphical representations of the biological pathways in which all the genes/proteins participate. AVAILABILITY: http://garban.tecnun.es.

Algorithms↗

PubMed2006

Rediscovering the species in community-wide predictive modeling.

Broadening the scope of conservation efforts to protect entire communities provides several advantages over the current species-specific focus, yet ecologists have been hampered by the fact that predictive modeling of multiple species is not directly amenable to traditional statistical approaches. Perhaps the greatest hurdle in community-wide modeling is that communities are composed of both co-occurring groups of species and species arranged independently along environmental gradients. Therefore, commonly used "short-cut" methods such as the modeling of so-called "assemblage types" are problematic. Our study demonstrates the utility of a multiresponse artificial neural network (MANN) to model entire community membership in an integrative yet species-specific manner. We compare MANN to two traditional approaches used to predict community composition: (1) a species-by-species approach using logistic regression analysis (LOG) and (2) a "classification-then-modeling" approach in which sites are classified into assemblage "types" (here we used two-way indicator species analysis and multiple discriminant analysis [MDA]). For freshwater fish assemblages of the North Island, New Zealand, we found that the MANN outperformed all other methods for predicting community composition based on multiscaled descriptors of the environment. The simple-matching coefficient comparing predicted and actual species composition was, on average, greatest for the MANN (91%), followed by MDA (85%), and LOG (83%). Mean Jaccard's similarity (emphasizing model performance for predicting species' presence) for the MANN (66%) exceeded both LOG (47%) and MDA (46%). The MANN also correctly predicted community composition (i.e., a significant proportion of the species membership based on a randomization procedure) for 82% of the study sites compared to 54% (MDA) and 49% (LOG), resulting in the MANN correctly predicting community composition in a total of 311 sites and an additional 117 sites (n = 379), on average, compared to LOG and MDA. The MANN also provided valuable explanatory power by simultaneously quantifying the nature of the relationships between the environment and both individual species and the entire community (composition and richness), which is not readily available from traditional approaches. We discuss how the MANN approach provides a powerful quantitative tool for conservation planning and highlight its potential for biomonitoring programs that currently depend on modeling discrete assemblage types to assess aquatic ecosystem health.

Animals↗

PubMed1988

[Prognostic and therapeutic significance of bone marrow biopsy in multiple myeloma. Analysis of 31 stage II A and III A patients].

The prognostic value of bone marrow biopsy was established in 31 patients suffering from stage IIA and IIIA myeloma (Durie and Salmon classification). Data obtained from quantitative marrow cytology permit to differentiate 3 sub-groups of cells: plasmocytes, plasmoblasts, plasmocytes/plasmoblasts of which the incidence on the prognosis and the response to treatment was studied. There is a correlation between the response to MP and the nature of various cells populations and, on the other hand, the type of infiltration. A sub-group of patients, resisting to MP, was identified: diffuse plasmoblastic myelomas of poor prognosis. Induction poly-chemotherapy seems far superior over the MP combination, which was always a controverted issue.

Aged↗

PubMed2003

Laryngeal carcinoma--multivariate analysis of prognostic factors in 1252 consecutive patients treated with primary radiotherapy.

Multivariate analyses of prognostic factors were carried out in 1252 consecutive patients with laryngeal squamous cell carcinoma treated with primary radical radiotherapy. Ten percent of patients had positive neck nodes Most of the patients were in stage I (48%), the remainder in stage II (24%), III (18%) and IV (10%). Of these patients, 746/1 252 (60%) were controlled by primary treatment but 506/1 252 (40%) had residual tumor or recurrent disease. The larynx was preserved in 62% of patients. The 5-year actuarial values for disease-specific and overall survival were 78% and 60%, respectively. The results of a univariate analysis showed multiple significant prognostic factors, and in a Cox proportional hazards model it was found that gender and T-classification were significant for T-failure, locoregional failure, death from cancer and death from all causes. The region of origin, nodal involvement, differentiation and pretreatment hemoglobin value were significant for several of the above-mentioned endpoints. Laryngeal carcinoma is curable when treated with primary radiotherapy, and this treatment confers a high degree of organ preservation. Independent prognostic factors in the multivariate analyses were gender, region of origin, T-stage, nodal involvement, differentiation and hemoglobin.

Adolescent↗

PubMed2005

Application of sliding-window discretization and minimization of stochastic complexity for the analysis of fAFLP genotyping fingerprint patterns of Vibrionaceae.

Minimization of stochastic complexity (SC) was used as a method for classification of genotypic fingerprints. The method was applied to fluorescent amplified fragment length polymorphism (fAFLP) fingerprint patterns of 507 Vibrionaceae representatives. As the current BinClass implementation of the optimization algorithm for classification only works on binary vectors, the original fingerprints were discretized in a preliminary step using the sliding-window band-matching method, in order to maximally preserve the information content of the original band patterns. The novel classification generated using the BinClass software package was subjected to an in-depth comparison with a hierarchical classification of the same dataset, in order to acknowledge the applicability of the new classification method as a more objective algorithm for the classification of genotyping fingerprint patterns. Recent DNA-DNA hybridization and 16S rRNA gene sequence experiments proved that the classification based on SC-minimization forms separate clusters that contain the fAFLP patterns for all representatives of the species Enterovibrio norvegicus, Vibrio fortis, Vibrio diazotrophicus or Vibrio campbellii, while previous hierarchical cluster analysis had suggested more heterogeneity within the fAFLP patterns by splitting the representatives of the above-mentioned species into multiple distant clusters. As a result, the new classification methodology has highlighted some previously unseen relationships within the biodiversity of the family Vibrionaceae.

Algorithms↗

PubMed2005

Consideration of role of radiotherapy for lymph node metastases in patients with HCC: retrospective analysis for prognostic factors from 125 patients.

OBJECTIVES: To evaluate the role of radiotherapy (RT) for hepatocellular carcinoma (HCC) patients with abdominal lymph node (LN) metastasis at our institution in the past 7 years. METHODS AND MATERIALS: We identified 125 patients with HCC metastasis to regional LNs treated with or without external beam RT (EBRT) between 1998 and 2004. Clinical characteristics collected included alpha-fetoprotein status, gamma-glutamyltransferase, status of intrahepatic tumors (size and number), previous therapy for intrahepatic tumors, metastatic LN status (location, number, and size), tumor thrombi, and Child-Pugh classification. Of the 125 patients, 62 received local limited EBRT and were classified as the EBRT group. They received locoregional LN irradiation. The tumor dose ranged from 40 to 60 Gy in daily 2.0-Gy fractions, 5 times weekly. Another 63 patients, who did not receive EBRT, were selected from hospitalized patients in the same period and were classified as the non-EBRT group. The parameters studied included survival rates and tumor response to EBRT both as demonstrated by clinical symptoms and as seen on CT. The Kaplan-Meier method was used to evaluate the survival rates, and the Cox regression model was used to identify predictors of outcome. RESULTS: After EBRT, partial responses and complete responses were observed in 37.1% and 59.7% of patients, respectively. The median survival was 9.4 months (95% confidence interval 5.8-13.0) for the EBRT group and 3.3 months (95% confidence interval, 2.7-3.9) for the non-EBRT group (p < 0.001). Multivariate analysis showed that multiple intrahepatic primary tumors, occurrence of tumor thrombi, no therapy for intrahepatic tumors, and greater Child-Pugh classification were related to a poorer prognosis in all patients. In the EBRT group, the survival periods decreased as the distance of LN involvement from the liver increased (following the natural flow of lymph) and was also associated with the intrahepatic primary tumor size. The incidence of death resulting from LN-related complications was lower in the EBRT group. CONCLUSION: Lymph node metastasis from HCC is sensitive to EBRT. EBRT with 25 fractions of 2 Gy is an effective palliative treatment for patients with LN metastases from HCC presenting with good performance status and may prolong overall survival.

Adult↗

PubMed1997

Secondary cytoreductive surgery at second-look laparotomy in advanced ovarian cancer: a Gynecologic Oncology Group Study.

Reports which analyzed the effects of secondary cytoreductive surgery at second-look laparotomy have often included small numbers of patients who have been treated with a variety of first-line chemotherapy regimens and those who may have progressed on first-line therapy. The purpose of this study was to analyze survival following secondary cytoreductive surgery at second-look laparotomy in patients with advanced ovarian cancer. Review of the surgical data of 153 patients allowed classification of tumor size found at second-look laparotomy and tumor size remaining after cytoreduction. Multivariate analysis evaluated multiple risk factors for survival. Of 153 patients, 124 had macroscopic tumor at second-look laparotomy and 29 had microscopic disease only. Fifteen of 69 (22%) patients were found to have tumor > 1 cm in diameter and were cytoreduced to microscopic residual and 18/69 (26%) were left with 1 cm tumor. Twenty-one of 55 (38%) patients with < or = 1 cm tumor were debulked to microscopic residual. The shortest survival relative to patients found to have microscopic disease at second-look laparotomy was observed among patients whose maximum tumor size remained > 1 cm following second-look laparotomy (relative risk = 3.1, P = 0.0004). No difference in survival was seen between patients found to have microscopic disease and those cytoreduced to microscopic disease (P = 0.24). The risk of death was lower among patients debulked to a lower category (< or = 1 cm debulked to microscopic, relative risk = 0.48, P = 0.02; > 1 cm reduced to < or = 1 cm, relative risk = 0.49, P = 0.02; > 1 cm reduced to microscopic, relative risk = 0.44, P = 0.01). Whether this apparent beneficial effect of cytoreductive surgery at second-look laparotomy reflects the biology of the tumor which allows surgical cytoreduction or the effects of cytoreduction can only be addressed in a randomized prospective trial.

Adult↗

PubMed1984

Use of logistic regression analysis to improve prediction of prognosis in acute myeloid leukaemia.

The prognostic usefulness of a range of factors has been examined for patients with acute myeloid leukaemia. Although there was a statistical association between some of these factors and remission rate, the association was only partial. To improve the usefulness of the data, multiple logistic regressional analysis was used. The features selected for use in the analysis were age, blood blast count, FAB classification and colony growth pattern. The last three features could be used as categorical variables, since blood blast counts of greater than 100 X 10(9)/1, FAB group 1 and a prolific pattern of colony growth were associated with a low remission rate. Age was used as a continuous variable. Using these features, eight regression groups were defined. Thus when this data for an individual patient is analysed, it is possible to obtain a value for the probability of that patient achieving remission.

Adult↗

PubMed2000

Classification of fusiform neocortical interneurons based on unsupervised clustering.

A classification of fusiform neocortical interneurons (n = 60) was performed with an unsupervised cluster analysis based on the comparison of multiple electrophysiological and molecular parameters studied by patch-clamp and single-cell multiplex reverse transcription-PCR in rat neocortical acute slices. The multiplex reverse transcription-PCR protocol was designed to detect simultaneously the expression of GAD65, GAD67, calbindin, parvalbumin, calretinin, neuropeptide Y, vasoactive intestinal peptide (VIP), somatostatin (SS), cholecystokinin, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, N-methyl-d-aspartate, and metabotropic glutamate receptor subtypes. Three groups of fusiform interneurons with distinctive features were disclosed by the cluster analysis. The first type of fusiform neuron (n = 12), termed regular spiking nonpyramidal (RSNP)-SS cluster, was characterized by a firing pattern of RSNP cells and by a high occurrence of SS. The second type of fusiform neuron (n = 32), termed RSNP-VIP cluster, predominantly expressed VIP and also showed firing properties of RSNP neurons with accommodation profiles different from those of RSNP-SS cells. Finally, the last type of fusiform neuron (n = 16) contained a majority of irregular spiking-VIPergic neurons. In addition, the analysis of glutamate receptors revealed cell-type-specific expression profiles. This study shows that combinations of multiple independent criteria define distinct neocortical populations of interneurons potentially involved in specific functions.

Action Potentials↗

PubMed2004

Left ventricular chamber stiffness at rest as a determinant of exercise capacity in heart failure subjects with decreased ejection fraction.

Impaired exercise tolerance, determined by peak oxygen consumption (VO2 peak), is predictive of mortality and the necessity for cardiac transplantation in patients with chronic heart failure (HF). However, the role of left ventricular (LV) diastolic function at rest, reflected by chamber stiffness assessed echocardiographically, as a determinant of exercise tolerance is unknown. Increased LV chamber stiffness and limitation of VO2 peak are known correlates of HF. Yet, the relationship between chamber stiffness and VO2 peak in subjects with HF has not been fully determined. Forty-one patients with HF New York Heart Association [(NYHA) class 2.4 +/- 0.8, mean +/- SD] had echocardiographic studies and VO2 peak measurements. Transmitral Doppler E waves were analyzed using a previously validated method to determine k, the LV chamber stiffness parameter. Multiple linear regression analysis of VO(2 peak) variance indicated that LV chamber stiffness k (r2 = 0.55) and NYHA classification (r2 = 0.43) were its best independent predictors and when taken together account for 59% of the variability in VO2 peak. We conclude that diastolic function at rest, as manifested by chamber stiffness, is a major determinant of maximal exercise capacity in HF.

Blood Pressure↗

PubMed1984

A comparison of MMPI profiles of heroin addicts based on multiple methods of classification.

MMPI profiles of 442 male narcotic addicts in a drug treatment program were classified according to one of three methods: (a) highest 2-point code, (b) cluster analysis, and (c) concordance with common actuarial rules of profile fit. Profiles were then compared with those previously reported in the research literature. While each method resulted in slightly different perspectives, each reported modal profiles analogous to the 49'/94', 42'/24', and 48'/84' profiles. A frequency table of 33 different profiles by rates per thousand were presented as prototypal base rates for future comparison.

Adult↗