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At least 199 records · Page 11Linked to original sources

PubMed2002

Comparison of predictive accuracy among six prognosis prediction systems for patient mortality in intensive care units.

BACKGROUND AND PURPOSE: This study compared the goodness-of-fit of six prognostic prediction systems. METHODS: A total of 1,170 patients in the medical and surgical intensive care units of a public tertiary care hospital were included in this study. Data from the Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE III, Simplified Acute Physiology Score II (SAPS II), Condition Index Score (CIS), and Mortality Probability Models II (MPM II; at admission MPM IIadm and 24-hours later MPM II24 h) prediction systems were collected. The scores or death-risks from these systems were compared between survivors and non-survivors. Lemeshow-Hosmer (LH) statistics, calibration curve, classification matrix, and receiver operating characteristic (ROC) curve for the whole study group were determined. Mortality ratio, LH statistics, and ROC curve for individual disease categories and operative states were compared. A model with good fit was defined as having an LH chi-square value close to the degrees of freedom and yielding a corresponding p value of greater than 0.05, conformation to the ideal calibration diagonal (low deviation value), high classification matrix overall accuracy, a large area under the ROC curve (> 0.8), and a mortality ratio close to 1. RESULTS: LH chi-square value was 12.37 for APACHE II and 8.61 for MPM II24 h. The calibration curve deviation value was 1.5069 for APACHE II and 1.4308 for MPM II24 h. Classification matrix overall accuracy was 78.88% for APACHE II and 79.54% for MPM II24 h. The area under the ROC curve was 0.779 for APACHE II and 0.790 for MPM II24 h. The mortality ratios of trauma were 1.00 for both APACHE II and MPM IIadm. The mortality ratios for respiratory diseases and rare diseases were both 1.02 for MPM II24 h. The other systems studied did not provide good-fit data. CONCLUSION: In this study, MPM II or APACHE II had the best predictive model of the tested systems for critically ill patients.

APACHE↗

PubMed1992

Evaluation of the predicted secondary structure of bacteriorhodopsin. Prediction of the bovine rhodopsin secondary structure and its sequence similarity with bacteriorhodopsin.

The secondary structure of bacteriorhodopsin (bacR) is predicted using the Chou and Fasman method in conjunction with the hydropathic index of Kyte and Doolittle. The predicted bacR structure was compared with the structure determined by Henderson et al. (1990) using electron diffraction and was found to correlate extremely well. The secondary structure of bovine rhodopsin (bovR) was then predicted using the same techniques. The proposed transmembrane regions of bovR were then examined and found to have sequence similarity with those transmembrane regions of bacR.

Amino Acid Sequence↗

PubMed1983

Prediction of lithium maintenance doses using a single point prediction protocol.

Conflicting reports regarding the utility of a previously described single point prediction dosing method for lithium prompted the present study's reexamination of the relationship between a single point lithium concentration and the lithium maintenance dose. Seventeen informed, adult patients with affective illness were studied. The relationship between their 24-hour lithium concentration after a test dose and the maintenance dose was significant, hence confirming earlier reports. In addition, more confident relationships were noted when steady state range concentrations for lithium prophylaxis (0.41 to 0.89 mEq/liter) and for treatment of acute mania (0.9 to 1.27 mEq/liter) were analyzed separately. Maintenance dose predictive equations were generated for these lithium steady state ranges from a 24-hour single point level after a 1200-mg test dose. The clinical usefulness of the new relationships observed for maintenance dose prediction must await prospective testing.

Adult↗

PubMed1995

Prediction in the presence of measurement error: general discussion and an example predicting defoliation.

Motivated by the particular problem of predicting defoliation based on a measure of gypsy moth egg mass density, prediction in the presence of measurement error is discussed. The measurement error variances and covariances are allowed to vary from unit to unit and are estimated by some type of within unit sampling. A general discussion is given as to when one should correct for the measurement error, and a method of estimating the prediction standard deviation is given when a correction is needed. The results are illustrated with the defoliation example.

Animals↗

PubMed2002

Successful prospective prediction of type 1 diabetes in schoolchildren through multiple defined autoantibodies: an 8-year follow-up of the Washington State Diabetes Prediction Study.

OBJECTIVE: Almost 90% of type 1 diabetes appears in individuals without a close family history. We sought to evaluate the best current predictive strategy, multiple defined autoantibodies, in a long-term prospective study in the general population. RESEARCH DESIGN AND METHODS: Autoantibodies to pancreatic islets (islet cell antibodies [ICAs]) and defined autoantibodies (d-aab) to human GAD, IA2/ICA512, and insulin were tested in 4,505 Washington schoolchildren. Eight years later, 3,000 (67%) subjects were recontacted, including 97% of subjects with any test >99th percentile. RESULTS: Six subjects developed diabetes (median interval 2.8 years), all from among the 12 individuals with multiple d-aab, representing 50% positive predictive value (95% CI 25-75%) and 100% sensitivity (58-100%). Among the others, diabetes occurred in 0 of 6 with one d-aab plus ICA, 0 of 26 with ICA only, 0 of 7 with one d-aab equaling the 99th percentile and another d-aab equaling the 97.5th percentile, 0 of 86 with one d-aab, and 0 of 2,863 with no d-aab or ICA. Adjusted for verification bias, multiple d-aab were 99.9% specific (99.86-99.93%). At this age, new d-aab seldom appeared. Once present, d-aab usually persisted regardless of disease progression, although less so for insulin autoantibodies. Insulin secretion by sequential glucose tolerance testing remained normal in four multiple d-aab subjects not developing diabetes. Of children developing diabetes, five of six (83%) would be included if HLA-DQ genotyping preceded antibody testing, but HLA-DQ did not explain outcomes among high-risk subjects, even when considered along with other genetic markers. CONCLUSIONS: Multiple d-aab were established by age 14 years and prospectively identified all schoolchildren who developed type 1 diabetes within 8 years.

Adolescent↗

PubMed2006

Predicting 5-fluorouracil chemosensitivity of liver metastases from colorectal cancer using primary tumor specimens: three-gene expression model predicts clinical response.

We identified genes related to 5-fluorouracil (5-FU) sensitivity in colorectal cancer and utilized these genes for predicting the 5-FU sensitivity of liver metastases. Eighty-one candidate genes involved in 5-FU resistance in gastric and colon cancer cell lines were previously identified using a cDNA microarray. In this study, the mRNA expression levels of these 81 selected genes and the genes of 5-FU-related enzymes, including thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and orotate phosphoribosyltransferase (OPRT), were measured using real-time quantitative RT-PCR assays of surgically resected materials from primary colorectal tumors in 22 patients. Clinical responses were estimated by evaluating the effects of 5-FU-based hepatic artery injection (HAI) chemotherapy for synchronous liver metastases. Four genes (TNFRSF1B, SLC35F5, NAG-1 and OPRT) had significantly different expression profiles in 5-FU-nonresponding and responding tumors (p < 0.05). A "Response Index" system using three genes (TNFRSF1B, SLC35F5 and OPRT) was then developed using a discriminate analysis; the results were well correlated with the individual chemosensitivities. Among the 11 cases with positive scores in our response index, 9 achieved a reduction in their liver metastases after 5-FU-based chemotherapy, whereas only 1 of the 11 cases with negative scores responded well to chemotherapy. Our "Response Index" system, consisting of TNFRSF1B, SLC35F5 and OPRT, has great potential for predicting the efficacy of 5-FU-based chemotherapy against liver metastases from colorectal cancer.

Aged↗

PubMed2004

In lung cancer patients, age, race-ethnicity, gender and smoking predict adverse comorbidity, which in turn predicts treatment and survival.

OBJECTIVE: This study evaluates the relationship between sociodemographic/exposure factors and comorbidity, and their impact on lung cancer treatment and survival. STUDY AND DESIGN SETTING: Data for 1,155 patients were abstracted from the Josephine Ford Cancer Center Tumor Registry and medical records. Associations were analyzed by linear, logistic, and Cox regression. RESULTS: Approximately 88% of patients had > or = 1 of 56 comorbidities assessed. In multivariate analysis, comorbidity count was associated with older age, pack-years smoked, heavy alcohol use, lower socioeconomic status (SES), and female gender. Approximately 63% of patients had > or = 1 of 18 adverse prognostic comorbidities (AC), and significant independent predictors of AC were age, pack-years, African-American race/ethnicity, and gender. In multivariate analysis, comorbidity count and AC predicted nonreceipt of surgery in localized disease (OR(> or = 1 vs. 0 AC)=0.38, 95% 0.18, 0.81) and chemotherapy in advanced disease (OR > or = 1 vs. 0 AC)=0.72, 95% 0.51, 1.00). In adjusted analysis, comorbidity predicted survival in localized (hazard ratio (HR)(> or = 2 vs. 0 AC)=2.99, 95% CI 1.75, 5.10) and advanced lung cancer (HR(> or = 2 vs. 0 AC)=1.56, 95% CI 1.25, 1.94). CONCLUSION: Comorbidity has important deleterious effects on lung cancer outcomes and significant predictors of comorbidity included age, smoking, race/ethnicity, SES, alcohol, and gender.

Age Factors↗

PubMed2005

Do health care providers' attitudes towards back pain predict their treatment recommendations? Differential predictive validity of implicit and explicit attitude measures.

The current study aimed to measure the differential predictive value of implicit and explicit attitude measures on treatment behaviour of health care providers. Thirty-six physiotherapy students completed a measure of explicit treatment attitude (Pain Attitudes And Beliefs Scale For Physiotherapists-PABS-PT) and a measure of implicit treatment attitude (Extrinsic Affective Simon Task-EAST). Furthermore, they gave treatment recommendations for a patient simulating back pain on three video scenes. The implicit and explicit measures of attitudes were only weakly related to each other. However, both were differentially related to treatment recommendations. The implications of the differential predictive value of implicit and explicit attitude measures for treatment behaviour are discussed.

Adult↗

PubMed1995

Predicting common bile duct lithiasis: determination and prospective validation of a model predicting low risk.

BACKGROUND: The aim of this two-part prospective study was: (1) to identify simple, noninvasive, preoperative factors associated with low or very low risk of common bile duct lithiasis (CBDL); and (2) to test the validity of the statistical model obtained during Part One by the postcholecystectomy follow-up of patients classified into a low-risk group. PATIENTS AND METHODS: In Part One of the study, preoperative clinical, biologic, and ultrasonographic data, and intraoperative cholangiographic findings were collected from 503 consecutive patients undergoing cholecystectomy for symptomatic lithiasis from 1985 to 1989. Using the data obtained in Part One, a linear logistic model was used prospectively in Part Two to determine the prediction of absence of CBDL in 279 consecutive patients. No jaundice, normal transaminase levels, common bile duct (CBD) diameter < 8 mm, and no intrahepatic duct enlargement defined the low-risk group of CBDL. RESULTS: In Part One, CBDL was present in 84 (17%) of all patients. Five parameters were used to classify 73% of all patients as low risk of CBDL and 27% as high risk. In the low-risk groups, CBDL was present in 1% of 116 cases with acute gallbladder complications, and 5% of 250 cases with no acute gallbladder complications. In Part Two, 171 (61%) patients were classified in the low-risk group (Group 1), and CBD stones were not sought by any additional preoperative investigations or intraoperative cholangiography (IOC). One hundred eight patients (39%) were considered at risk of CBDL (Group 2). Mean follow-up was 20.6 months (median 19); 2 patients (1%) in the low-risk group presented a symptomatic retained stone. CONCLUSIONS: This study validated this simple model for predicting risk of CBDL and avoiding invasive preoperative investigations--as well as IOC--in more than 60% of symptomatic cholelithiases. In addition, this model seemed useful for defining patients in whom further exploration for CBDL was justified, since 42 (39%) of the 108 Group 2 patients were proved to have CBDL.

Analysis of Variance↗

PubMed1996

Research to develop a predicting system of mammalian subacute toxicity, (3). Construction of a predictive toxicokinetics model.

A new predictive toxicokinetics model was developed to estimate subacute toxicity (target organs, severity, etc.) of non-congeneric industrial chemicals, where the chemical structures and physico-chemical properties are only available. Thus, a physiological pharmacokinetics model, which consists of blood, liver, kidney (these were experimentally found as major toxicological targets), muscle and fat compartments, was established to simulate the chemical concentrations in organs/tissues with pharmacokinetic parameters by means of Runge-Kutta-Gill algorithm. The pharmacokinetic parameters, i.e. absorption rate, absorption ratio, hepatic extraction ratio of metabolism and renal clearance were calculated by using separately established Quantitative Structure-Pharmacokinetics Relationship equations. The developed predictive model was then applied to simulations of 43 non-congeneric industrial chemicals. The chemical concentrations in organs/tissues after single oral administration were simulated, and their maximum concentrations (Cmax's) and area under the concentration-time curves (AUC's) were calculated. Fast Inverse Laplace Transform was newly applied for the purpose of simulation of 28-day repeated dose toxicity. Simulated concentrations of 28 days repeated dose were, however, found to be the same as those of simple repetitions of a single administration per day because of the short half-lives of non-congeneric industrial chemicals. A comparison of subacute toxicity data with Cmax's and AUC's in a single dose scenario suggested that the organs/tissues with relatively high concentrations of tested chemical substances were the most sensitive targets within a chemical. Chemical concentrations in liver, for instance, were correlated with the severity of hepatotoxicity among the chemicals. It was also suggested that to improve and widen the present approach, data of metabolite and reactivity of non-congeneric industrial chemicals to organs/tissues, receptors, etc. should be incorporated into the model.

Adipose Tissue↗

PubMed1999

Sensitivity, specificity and predictive value of tympanometry in predicting a hearing impairment in otitis media with effusion. MRC Multi-Centre Otitis Media Study Group.

Children with otitis media with effusion (OME) need monitoring over time to identify persistence of disease and to assess their hearing thresholds as a surrogate of auditory disability. It would be useful if tympanometry could be used to predict those with an impairment. This study looked at 1153 children, aged between 3.25 and 6.75 years, referred for suspected OME. The inclusion of type C2 tympanograms with type B tympanograms versus all other tympanogram types increased the sensitivity of detecting air-conduction thresholds and air-bone gaps of various magnitudes in the better hearing ear but lowered the specificity and the positive predictive value. Extending the pressure range to -600 daPa and excluding the 30% of children with poor concentration on audiometry made no difference to the sensitivity and specificity. The results were the same for the poorer hearing ear. These findings are of practical help in monitoring children with OME. Thus taking an air-conduction average of 25 dB HL in the better ear as the level needing detection, if all children are audiometrically assessed then 100% of those with an impairment will be identified. Limiting audiometry to those with a bilateral type B tympanogram reduces the workload by 50%, but 90% of impaired children will still be detected. Limiting audiometry to those with type B or C2 tympanograms reduces the workload to 69% of the sample, and 95% of impaired children will be identified. With such data, decisions as to how to allocate limited audiometric resources for monitoring children with OME are made easier.

Acoustic Impedance Tests↗

PubMed2002

Predictive validity of a measure of treatment readiness for out-of-treatment drug users: enhancing prediction beyond demographic and drug history variables.

The predictive validity of a treatment readiness measure designed for out-of-treatment drug users, tapping dimensions of perceived problem severity, perceived need for formal treatment, motivation for treatment, and negative attitudes toward treatment is examined using data from a National Institute on Drug Abuse (NIDA)-funded HIV outreach intervention in San Antonio, Texas. Logistic regression is used to predict use of substance abuse treatment services three months after program intake on the basis of readiness scores, controlling for demographic and drug history variables. Analyses of data from 673 drug users in an HIV outreach intervention indicated that treatment readiness dimensions accounted for a 12% increase in variation in "use of any modality" and 14% for "use or attempted service use". Only Motivation to Quit was a significant predictor of "use of any modality" and both Perceived Need for Treatment and Motivation to Quit were significant predictors of "use or attempted use". Findings support the importance of the individual's perception of "readiness" to change their substance-abusing behavior and enter treatment.

Adult↗

PubMed2003

Prediction of sites of coronary atherosclerosis progression: In vivo profiling of endothelial shear stress, lumen, and outer vessel wall characteristics to predict vascular behavior.

PURPOSE OF REVIEW: Native atherosclerosis and in-stent restenosis are focal and evolve independently. The endothelium regulates arterial behavior by responding to its local environment of hemodynamic stresses, in particular, shear stress. Identification of endothelial shear stress and arterial wall characteristics may allow for the prediction of the progression of atherosclerosis. Accurate identification of arterial segments at high risk for progression may permit preemptive intervention strategies to avoid adverse coronary events. RECENT FINDINGS: In vitro studies indicate that low endothelial shear stress upregulates the genetic and molecular responses leading to the initiation and progression of atherosclerosis, and promotes inflammation and formation of other features characteristic of vulnerable plaque. Physiologic endothelial shear stress is vasculoprotective and fosters quiescence of the endothelium and vascular wall. High endothelial shear stress promotes platelet aggregation. Recent studies have now provided evidence that endothelial shear stress and vascular wall morphology along the course of human coronary arteries can be characterized in vivo, and, in serial studies, may actually predict the focal areas in which atherosclerosis progression occurs. SUMMARY: Rapidly evolving methodologies are able to characterize the arterial wall and the local hemodynamic environmental factors likely responsible for progression of coronary disease in humans. These new diagnostic modalities allow for identification of plaque progression. Future studies need to identify the factors responsible for vulnerable plaque formation. The current availability of drug-eluting stents with a low risk of restenosis allows for consideration of preemptive intervention strategies for these high-risk vascular sites such that future adverse coronary events can be averted.

Coronary Artery Disease↗

PubMedDate not supplied

[A possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction by early radiation response ].

The experiments on dogs and monkeys have shown that the severity of radiation sickness following the exposure to supralethal radiation doses can be predicted by early response of an individual. For such prediction, the most informative criteria include general severity of clinical manifestations during primary radiation response and evaluated within a few post-damage hours, the degree of tension in cardiac rhythm control, the cortisol level, the endocrine status index.

Animals↗

PubMedDate not supplied

[Evaluation of thermal comfort in a student population: predictive value of an integrated index (Fanger's predicted mean value].

Practical applications and predictive values of a thermal comfort index (Fanger's PRV) were verified on a sample school population (1236 subjects) by studying the relationships between thermal sensations (subjective analysis), determined by means of an individual questionnaire, and the values of thermal comfort index (objective analysis) obtained by calculating the PMV index individually in the subjects under study. In homogeneous conditions of metabolic expenditure rate and thermal impedence from clothing, significant differences were found between the two kinds of analyses. At 22 degrees C mean radiant and operative temperature, the PMV values averaged 0 and the percentage of subjects who experienced thermal comfort did not exceed 60%. The high level of subjects who were dissatisfied with their environmental thermal conditions confirms the doubts regarding the use of the PMV index as a predictive indicator of thermal comfort, especially considering that the negative answers were not homogeneous nor attributable to the small thermal fluctuations (less than 0.5 degree C) measured in the classrooms.

Adolescent↗

PubMed1991

The prediction of suicide. Sensitivity, specificity, and predictive value of a multivariate model applied to suicide among 1906 patients with affective disorders.

Stepwise multiple logistic regression was utilized in an attempt to develop a statistical model that would predict suicide in a group of 1906 Iowans with affective disorders admitted to a tertiary care hospital. The risk factors identified by this approach included the number of prior suicide attempts, suicidal ideation on admission, bipolar affective disorder (manic or mixed type), gender, outcome at discharge, and unipolar depressive disorder in individuals with a family history of mania. However, the model failed to identify any of the patients who committed suicide. The results appear to support the contention that, based on present knowledge, it is not possible to predict suicide, even among a high-risk group of inpatients.

Adult↗

PubMed2004

Fine-tuning the prediction of sequences cleaved by signal peptidase II: a curated set of proven and predicted lipoproteins of Escherichia coli K-12.

A curated set of 81 proven and 44 predicted lipoproteins of Escherichia coli K-12 was defined with the combined use of a literature survey, a variety of predictive tools and human expertise. The well-documented Gram-negative proteome of E. coli K-12 was chosen to assess how the different approaches complement each other and to ensure a stable definition of a consistent set of lipoproteins. The results of detailed analysis of such proteins at the level of a single proteome are presented, corroborated and rationalized.

Amino Acid Motifs↗

PubMed1996

Correlation of in vivo topical efficacies with in vitro predictions using acyclovir formulations in the treatment of cutaneous HSV-1 infections in hairless mice: an evaluation of the predictive value of the C* concept.

The purpose of this study was to carry out an extensive examination of the C* concept for prediction of the topical antiviral efficacies of acyclovir (ACV) formulations in a hairless mouse model for the treatment of cutaneous herpes simplex virus type-1 (HSV-1) infections. This method is based on estimation of the free drug concentration at the target site (C*), which is presumed to be the basal cell layer of the epidermis. Five different formulations (containing 5% ACV) were examined in a finite dose multiple dosing regimen (twice a day application) to simulate the clinical situation. For determination of C*, in vitro ACV fluxes across the hairless mouse skin were measured in an in vivo-in vitro experimental design that approximated the in vivo antiviral treatment protocol. Then, the in vivo antiviral efficacies were measured using a 1-day delayed (after HSV-1 virus inoculation) 4-day treatment protocol. 10 microL/cm2 dose of ACV formulation was applied every 12 h for 4 days after which the lesions were scored and efficacies were calculated. Our results indicate that, over a wide range of efficacies, the predictions based on C* (estimated from the experimental fluxes) are in good agreement with the in vivo antiviral efficacies. These studies, therefore, support the validity of the C* concept for various ACV formulations and suggest that the C* approach has potential for future practical situations.

Acyclovir↗