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PubMedDate not supplied

An engineering model of dynamic cardiomyoplasty. II. Clinical applications.

Previously, a modification to the Sunagawa engineering model for the isolated left ventricle and arterial system was proposed and validated for dynamic cardiomyoplasty in an acute goat preparation. To test the hypothesis that this model may be applied to the clinical scenario in cardiomyoplasty patients, we predicted human stroke volume using the model with human clinical data from the literature. Predicted stroke volume correlated well with published stroke volume in patients who have had the dynamic cardiomyoplasty procedure. These results suggest that the modest hemodynamic improvement commonly reported after the procedure is performed may be due to diminished latissimus dorsi strength after transformation. The validity of both the original Sunagawa model and the previously proposed modification for dynamic cardiomyoplasty is further supported with these results. A nomogram methodology for predicting stroke volume after dynamic cardiomyoplasty for any particular patient is presented.

Biomechanical Phenomena↗
PubMed2004

The role of uroflowmetry in diagnosis of infravesical obstruction in the patients with benign prostatic enlargement.

OBJECTIVE: Determine sensitivity and specificity of uroflowmetry in the diagnosis of clear defined outlet obstruction in the patients with benign prostatic enlargement (BPE). MATERIALS AND METHODS: 102 patients with proved BPE, after fulfilling International Prostatic Symptom Score (I-PSS), underwent complete urodynamic measurements (uroflowmetry, cystometry and pressure/flow studies). The patients were dichotomized in obstruction zone or out of obstruction, according to the models presented in the literature, but also with combination of Schafer and URA nomograms. Then sensitivity and specificity of uroflowmetry (with cut-off point of Qmax < 10 ml/sec) to the obstruction were determined, as well as to the level of I-PSS. RESULTS: 52 patients (51%) had Qmax < 10 ml/sec. T-test has shown that noninvasive variables (age, level of I-PSS, volume of prostate, volume of post void residual or voided volume) differ among the patients of two observed groups (p < 0.05). Discriminant validity of Qmax < 10 ml/sec for diagnosis of clear defined urodynamic obstruction (combination of URA and Schafer nomograms) is calculated by ROC curve, with excellent area of 0.92 (p < 0,00001). According to the levels of I-PSS, the patients were trichotomized. Increase of uroflowmetry sensitivity and specificity to the obstruction by increment of symptoms is noticed. Post-test probability (accuracy) for Qmax < 10 ml/sec to the obstruction for the patients with mild symptoms was 84%, while the same test in the groups of the patients with moderate and severe symptoms were 93% and 95%, respectively. CONCLUSION: Value of uroflowmetry, as non-invasive tool in the diagnosis of outlet obstruction is enhanced by accurate defining of obstruction, but also with increase of the lower urinary tract symptoms. By this mean, clinical decision making in the treatment for the individual BPE patient is easier.

Aged↗
PubMed2026

Could the preoperative urethral curve be used to predict immediate urinary continence following Retzius-sparing robot-assisted radical prostatectomy? A retrospective multi-center study.

PURPOSE: Immediate urinary continence (UC) recovery following Retzius-sparing robot-assisted radical prostatectomy (RS-RARP) remains highly variable, highlighting the need for reliable preoperative prediction. We aimed to develop and validate models to identify patients likely to achieve immediate UC recovery following RS-RARP. MATERIALS AND METHODS: A total of 580 prostate cancer patients who underwent RS-RARP from four medical centers were assigned to a training set (n=348), an internal validation set (n=103) and an external validation set (n=129). Independent predictors were identified through univariate analysis and LASSO regression. A nomogram was constructed using multivariate logistic regression. Its performance was evaluated with receiver operating characteristic (ROC) curve, calibration curves, and decision curve analysis. RESULTS: Immediate UC recovery was observed in 84.5% (294/348) of patients in the training cohort, 80.6% (83/103) in the internal validation cohort, and 81.4% (105/129) in the external validation cohort, respectively. Multivariate analysis identified membranous urethral length (MUL) (OR=1.23, P=0.029) and urethral curvature (OR=2.84, P<0.001) as independent predictors, while prostate volume (PV) (OR=0.84, P <0.001) as a protective factor. The nomogram integrating MUL, PV, and urethral curvature demonstrated superior predictive accuracy, with an AUC of 0.87 (95% CI, 0.83-0.91) in the training cohort. The bootstrap-corrected calibration slope was 0.96, and the Brier score was 0.08.&#xa0;Calibration curves and decision curve analysis confirmed the predictive accuracy and clinical utility of the nomogram. CONCLUSIONS: Our study introduces a novel quantitative method for assessing urethral curvature. The mpMRI-based model, integrating urethral curvature and prostate spatial configuration, offers enhanced predictive accuracy for postoperative immediate UC recovery.

Humans↗
PubMed2006

Precystectomy nomogram for prediction of advanced bladder cancer stage.

OBJECTIVE: To evaluate precystectomy prediction of pT and pN stages at cystectomy. METHODS: Multivariate logistic regression analyses modelled variables of 726 evaluable patients treated with radical cystectomy and bilateral pelvic lymphadenectomy. The first set of models predicted pT(3-4) stage at cystectomy, and the second set predicted pN(1-3) stages at cystectomy. Transurethral resection (TUR) predictors consisted of 2002 T stage, 1973 WHO tumour grade, presence of carcinoma in situ, age, gender, and delivery of neo-adjuvant chemotherapy. The area under the ROC curve quantified nomogram accuracy. Two hundred bootstrap resamples were used to reduce overfit bias. RESULTS: At TUR, 11% of patients were staged as pT(3-4) versus 42% at cystectomy. Lymph node metastases were found in 24% of patients at cystectomy (pN(1-3)). The multivariate pT(3-4) nomogram was 75.7% accurate versus 71.4% for TUR T stage. The multivariate pN(1-3) nomogram was 63.1% accurate versus 61.0% for TUR T stage. CONCLUSION: Multivariate nomograms are not perfect, but they do predict more accurately than TUR T stage alone.

Adult↗
PubMed1982

Parameter optimisation in clinical pharmacokinetics.

This paper describes a package of computer programs designed to be used in Clinical Pharmacokinetics or Clinical Chemistry Laboratories to assist in the interpretation of plasma drug concentration measurements. A simple pharmacokinetic model is utilised, and values of the necessary parameters for the general population determined using standard nomograms. Parameter estimates for individual patients are obtained by a feedback process using Bayes' theorem and the principle of maximum likelihood. Thus optimal dosage regimes can be obtained for individual patients. The package can be used with a series of drugs.

Clinical Laboratory Techniques↗
PubMed1993

Construction of the flow rate nomogram using polynomial regression.

The urinary flow rates of normal individuals depend on the initial bladder volume in a non-linear fashion (J. Urol. 109 (1973) 874). A flow rate nomogram was developed by Siroky, Olsson and Krane, (J. Vol. 122 (1979) 665), taking the non-linear relationship into account, as an aid in the interpretation of urinary flow rate data. The use of a flow rate nomogram is to differentiate normal from obstructed individuals and is useful in the post operative follow-up of urinary outflow obstruction. It has been shown (J. Urol. 123 (1980) 123) that the flow rate nomogram is an objective measure of the efficacy of medical or surgical therapy. Instead of manually reading nomogram values from the flow rate nomogram, an algorithm is developed using polynomial regression to fit the flow rate nomograms and hence compute nomogram values directly from the fitted nomogram equations.

Humans↗
PubMed1983

Theoretical analysis of "metabolic indices" of blood buffer system.

The well-known base excess (BE) and buffer base (BB) curves of Siggaard-Andersen's nomogram are based on their empirical finding that the blood buffer lines in the pH-log PCO2 coordinates with the same BE (or BB) always pass through a single point irrespective of the hemoglobin concentration. We have analytically derived the BE and BB curves on the assumption of a two-compartmental model of blood buffer system comprised of plasma and red blood cells. These hyperbolic functions of BE and BB curves fitted the Siggaard-Andersen's observation very well. The simple formulas derived from the buffer equation with the parameters obtained on the least-square basis were shown to estimate "metabolic indices" of blood as accurately as the computer reading of the nomographic curves. These results seem to indicate that the buffer equation based on the two-compartmental model describes the acid-base status of blood satisfactorily, and that it can entirely replace the Siggaard-Andersen's nomogram.

Acid-Base Equilibrium↗
PubMed2005

Sample sizes for clinical trials with time-to-event endpoints and competing risks.

We consider clinical trials where the time to occurrence of events in the presence of competing risks is the primary endpoint for treatment evaluation. The number of events with regard to the defined primary endpoint required to ensure the specified power can be calculated according to Schoenfeld's formula like in classical survival studies. However, determination of the number of patients that have to be recruited to observe the calculated number of events requires specification of the length of the accrual period, the trial duration and assumptions about the event-specific hazard functions. Information from previous studies about expected failure rates for the reference treatment is useful and can be translated into assumptions about the appropriate model parameters. A formula for sample size computation is presented for two competing outcome states. Nomograms help to communicate different alternatives of duration and size of the trial to interdisciplinary committees whose members plan and monitor the clinical trial. The 4D trial (Die Deutsche Diabetes Dialyse Studie) designed to compare lipid lowering treatment with HMG-CoA reductase inhibitor atorvastatin with placebo in type 2 diabetic patients on hemodialysis with respect to time to the composite event "cardiovascular death or non-fatal myocardial infarction" is used as an example to outline the statistical methods.

Clinical Trials Data Monitoring Committees↗
PubMed2006

Comparative pharmacokinetics of Panadol Extend and immediate-release paracetamol in a simulated overdose model.

BACKGROUND: Panadol Extend is a modified-release paracetamol formulation in which each 665 mg tablet contains 69% slow-release and 31% immediate-release paracetamol. There are no data on Panadol Extend pharmacokinetics in overdose. It is unknown whether the paracetamol treatment nomogram can be used to make decisions regarding the toxicity of this product in overdose. OBJECTIVE: To compare the pharmacokinetics of Panadol Extend and immediate-release paracetamol (APAP-IR) in simulated overdose model in healthy volunteers. METHODS: Cross-over study using a dose of 90 mg/kg ideal body weight of Panadol Extend or APAP-IR in seven healthy volunteers. Serum paracetamol concentrations were measured over 12 h. Maximal paracetamol concentration (Cmax), time to Cmax (Tmax), area under the curve (AUC) and elimination half-life (t(1/2)) were compared. RESULTS: Mean paracetamol dose was 73 mg/kg actual body weight. Panadol Extend produced lower Cmax (0.208 mmol/L +/- 0.02 vs 0.48 mmol/L +/- 0.02, P = 0.0001) and AUC(0-12 h) when compared with APAP-IR. Tmax was delayed with Panadol Extend (2.83 h +/- 0.26 vs 0.94 h +/- 0.17, P = 0.0001). Absorption was complete in all subjects by 4 h post ingestion in both study arms. Elimination t(1/2) was 1.69 +/- 0.09 h for APAP-IR and 1.65 +/- 0.13 h for Panadol Extend (not significant). CONCLUSIONS: Reductions in Panadol Extend Cmax and AUC(0-12 h) might be related to elimination occurring during the absorption phase. In this model of Panadol Extend moderate overdose, Tmax was significantly delayed. In larger overdoses, time to peak paracetamol levels might be further delayed, because of continuing absorption from the formulation. Therefore, the paracetamol treatment nomogram might not reliably predict hepatotoxicity from Panadol Extend if paracetamol levels are measured too early.

Absorption↗
PubMed2025

Construction of a prognostic model for gastric cancer based on immune infiltration and microenvironment, and exploration of MEF2C gene function.

BACKGROUND: Advanced gastric cancer (GC) exhibits a high recurrence rate and a dismal prognosis. Myocyte enhancer factor 2c (MEF2C) was found to contribute to the development of various types of cancer. Therefore, our aim is to develop a prognostic model that predicts the prognosis of GC patients and initially explore the role of MEF2C in immunotherapy for GC. METHODS: Transcriptome sequence data of GC was obtained from The Cancer Genome Atlas (TCGA), the Gene Expression Omnibus (GEO) and PRJEB25780 cohort for subsequent immune infiltration analysis, immune microenvironment analysis, consensus clustering analysis and feature selection for definition and classification of gene M and N. Principal component analysis (PCA) modeling was performed based on gene M and N for the calculation of immune checkpoint inhibitor (ICI) Score. Then, a Nomogram was constructed and evaluated for predicting the prognosis of GC patients, based on univariate and multivariate Cox regression. Functional enrichment analysis was performed to initially investigate the potential biological mechanisms. Through Genomics of Drug Sensitivity in Cancer (GDSC) dataset, the estimated IC50 values of several chemotherapeutic drugs were calculated. Tumor-related transcription factors (TFs) were retrieved from the Cistrome Cancer database and utilized our model to screen these TFs, and weighted correlation network analysis (WGCNA) was performed to identify transcription factors strongly associated with immunotherapy in GC. Finally, 10 patients with advanced GC were enrolled from Sun Yat-sen University Cancer Center, including paired tumor tissues, paracancerous tissues and peritoneal metastases, for preparing sequencing library, in order to perform external validation. RESULTS: Lower ICI Score was correlated with improved prognosis in both the training and validation cohorts. First, lower mutant-allele tumor heterogeneity (MATH) was associated with lower ICI Score, and those GC patients with lower MATH and lower ICI Score had the best prognosis. Second, regardless of the T or N staging, the low ICI Score group had significantly higher overall survival (OS) compared to the high ICI Score group. For its mechanisms, consistently, for Camptothecin, Doxorubicin, Mitomycin, Docetaxel, Cisplatin, Vinblastine, Sorafenib and Paclitaxel, all of the IC50 values were significantly lower in the low ICI Score group compared to the high ICI Score group. As a result, based on univariate and multivariate Cox regression, ICI Score was considered to be an independent prognostic factor for GC. And our Nomogram showed good agreement between predicted and actual probabilities. Based on CIBERSORT deconvolution analysis, there was difference of immune cell composition found between high and low ICI Score groups, probably affecting the efficacy of immunotherapy. Then, MEF2C, a tumor-related transcription factor, was screened out by WGCNA analysis. Higher MEF2C expression is significantly correlated with a worse OS. Moreover, its higher expression is also negatively correlated with tumor mutation burden (TMB) and microsatellite instability (MSI), but positively correlated with several immunosuppressive molecules, indicating MEF2C may exert its influence on tumor development by upregulating immunosuppressive molecules. Finally, based on transcriptome sequencing data on 10 paired tumor tissues from Sun Yat-sen University Cancer Center, MEF2C expression was significantly lower in paracancerous tissues compared to tumor tissues and peritoneal metastases, and it was also lower in tumor tissues compared to peritoneal metastases, indicating a potential positive association between MEF2C expression and tumor invasiveness. CONCLUSIONS: Our prognostic model can effectively predict outcomes and facilitate stratification GC patients, offering valuable insights for clinical decision-making. The identified transcription factor MEF2C can serve as a biomarker for assessing the efficacy of immunotherapy for GC.

Humans↗
PubMed2003

Use of nomograms for predicting survival in patients with castrate prostate cancer.

Given the heterogeneity of prognoses in patients with castrate metastatic prostate cancer, the ability to accurately predict survival is vital for optimal patient counseling, selection of treatments, clinical trial design, and interpretation of clinical data. Over the past 20 years, several prognostic models have been developed in an attempt to refine the clinician's predictive ability. Early models were based on patients with more advanced disease. They included variables that are no longer regularly encountered today and involved cumbersome calculations that were not practical for everyday use in the clinic. Recently, 2 point-based nomograms have been developed based on pretreatment variables measured on a routine basis. These models provide a user-friendly format in which to make sophisticated predictions of survival. These models have improved our ability to predict the outcomes of patients with castrate metastatic disease. However, further work to identify novel prognostic markers to improve the accuracy of these predictions is needed.

Adenocarcinoma↗
PubMed2006

Significant upgrading affects a third of men diagnosed with prostate cancer: predictive nomogram and internal validation.

OBJECTIVE: To explore the rate of significant upgrading from biopsy to radical prostatectomy (RP) specimens in a contemporary cohort, and to develop a prognostic model capable of predicting the probability of significant upgrading, as previous reports indicate that up to 43% of men with low-grade prostate cancer at biopsy will be diagnosed with high-grade cancer at RP. PATIENTS AND METHODS: The study cohort comprised 4789 men (median age 63 years, range 39-82) treated with RP, with available clinical stage, prostate-specific antigen levels, biopsy and RP Gleason sum values. These variables were used as predictors in multivariate logistic regression models (LRMs) addressing the rate of significant Gleason sum upgrading, defined as a Gleason sum increase either from < or = 6 to > or = 7 or from 7 to > or = 8 between the biopsy and RP specimens. Regression coefficients were used to develop and validate (200 bootstrap re-samples) a nomogram predicting significant biopsy Gleason sum upgrading. RESULTS: Significant biopsy Gleason sum upgrading was recorded in 1349 (28.2%) patients. In multivariate LRMs, all predictors were highly significant (all P < 0.001). The bootstrap-corrected accuracy of the nomogram predicting the probability of significant Gleason sum upgrading between biopsy and RP specimens was 75.7%. CONCLUSION: Our nomogram might prove highly useful when the possibility of a more aggressive Gleason variant could change the treatment options.

Adult↗
PubMed2003

Predictors of hospital mortality in the global registry of acute coronary events.

BACKGROUND: Management of acute coronary syndromes (ACS) should be guided by an estimate of patient risk. OBJECTIVE: To develop a simple model to assess the risk for in-hospital mortality for the entire spectrum of ACS treated in general clinical practice. METHODS: A multivariable logistic regression model was developed using 11 389 patients (including 509 in-hospital deaths) with ACS with and without ST-segment elevation enrolled in the Global Registry of Acute Coronary Events (GRACE) from April 1, 1999, through March 31, 2001. Validation data sets included a subsequent cohort of 3972 patients enrolled in GRACE and 12 142 in the Global Use of Strategies to Open Occluded Coronary Arteries IIb (GUSTO-IIb) trial. RESULTS: The following 8 independent risk factors accounted for 89.9% of the prognostic information: age (odds ratio [OR], 1.7 per 10 years), Killip class (OR, 2.0 per class), systolic blood pressure (OR, 1.4 per 20-mm Hg decrease), ST-segment deviation (OR, 2.4), cardiac arrest during presentation (OR, 4.3), serum creatinine level (OR, 1.2 per 1-mg/dL [88.4- micro mol/L] increase), positive initial cardiac enzyme findings (OR, 1.6), and heart rate (OR, 1.3 per 30-beat/min increase). The discrimination ability of the simplified model was excellent with c statistics of 0.83 in the derived database, 0.84 in the confirmation GRACE data set, and 0.79 in the GUSTO-IIb database. CONCLUSIONS: Across the entire spectrum of ACS and in general clinical practice, this model provides excellent ability to assess the risk for death and can be used as a simple nomogram to estimate risk in individual patients.

Aged↗
PubMed1999

Pretreatment nomogram for prostate-specific antigen recurrence after radical prostatectomy or external-beam radiation therapy for clinically localized prostate cancer.

PURPOSE: To present nomograms providing estimates of prostate-specific antigen (PSA) failure-free survival after radical prostatectomy (RP) or external-beam radiation therapy (RT) for men diagnosed during the PSA era with clinically localized disease. PATIENTS AND METHODS: A Cox regression multivariable analysis was used to determine the prognostic significance of the pretreatment PSA level, 1992 American Joint Committee on Cancer (AJCC) clinical stage, and biopsy Gleason score in predicting the time to posttherapy PSA failure in 1,654 men with T1c,2 prostate cancer managed with either RP or RT. RESULTS: Pretherapy PSA, AJCC clinical stage, and biopsy Gleason score were independent predictors (P < .0001) of time to posttherapy PSA failure in patients managed with either RP or RT. Two-year PSA failure rates derived from the Cox regression model and bootstrap estimates of the 95% confidence intervals are presented in the format of a nomogram stratified by the pretreatment PSA, AJCC clinical stage, biopsy Gleason score, and local treatment modality. CONCLUSION: Men at high risk (> 50%) for early (< or = 2 years) PSA failure could be identified on the basis of the type of local therapy received and the clinical information obtained as part of the routine work-up for localized prostate cancer. Selection of these men for trials evaluating adjuvant systemic and improved local therapies may be justified.

Humans↗
PubMed2005

Development and internal validation of a nomogram predicting the probability of prostate cancer Gleason sum upgrading between biopsy and radical prostatectomy pathology.

OBJECTIVE: Previous reports indicate that as many as 43% of men with low grade PCa at biopsy will be diagnosed with high-grade PCa at RP. We explored the rate of upgrading from biopsy to RP specimen in our contemporary cohort, and developed a model capable of predicting the probability of biopsy Gleason sum upgrading. MATERIALS AND METHODS: The study cohort consisted of 2982 men treated with RP, with available clinical stage, serum prostate specific antigen and biopsy Gleason scores. These clinical data were used as predictors in multivariate logistic regression models (LRM) addressing the rate of Gleason sum upgrading between biopsy and RP pathology. LRM regression coefficients were used to develop a nomogram predicting the probability of Gleason sum upgrading and was subjected to 200 bootstrap resamples for internal validation and to reduce overfit bias. RESULTS: Overall, 875 patients were upgraded (29.3%). In multivariate LRMs, all predictors were highly significant (all p values <0.0001). Bootstrap-corrected predictive accuracy of the nomogram predicting the probability of Gleason sum upgrading between biopsy and RP was 0.804. CONCLUSION: We developed a highly accurate clinical aid for treatment decision-making. It may prove useful when the possibility of a more aggressive Gleason variant may change the treatment options.

Biopsy↗
PubMed2003

Amniotic fluid index measured with the aid of color flow Doppler.

OBJECTIVE: To determine whether using color flow Doppler to identify the umbilical cord affects amniotic fluid index (AFI) measurements. METHODS: A total of 2236 AFI measurements between 24 and 42 weeks in singleton gestations with no known or suspected fetal anomalies and < 14 days' discrepancy between menstrual and ultrasonographic dating were included. Color flow Doppler was used to identify loops of umbilical cord; these were excluded from the measurement. Polynomial regression was used to generate means and centiles. Data were grouped according to completed weeks of gestation and descriptive statistics were calculated. At each week of gestation, the number and percentage of pregnancies diagnosed as < or = 2.5th, < or = 5th, > or = 95th, and > or = 97.5th centile according to a 'standard' nomogram derived without using color flow Doppler were calculated. RESULTS: The AFI decreased significantly over gestational age, starting at 31 weeks (p < 0.05 by ANOVA). The relationship between AFI and gestational age was best modeled by a second-degree polynomial (p < 0.001). The median and range of the proportion of AFIs that fell outside the ranges of the standard nomogram at each completed gestational age was: 6.0 (2.3-35.4)% for the < or = 2.5th centile, 9.9 (3.1-37.5)% for the < or = 5th centile, 3.8 (0-30)% for the > or = 95th centile, and 1.8 (0-20)% for the > or = 97.5th centile. The 2.5th and 5th centiles using the current data were lower than those of the 'standard', and the difference increased with advancing gestation. Upper centiles were also different. CONCLUSION: The AFI measured using color flow Doppler overestimates oligohydramnios and may underestimate polyhydramnios when a standard AFI table obtained without color flow Doppler is used. Normal values specific for measurement method should be used for reference.

Amniotic Fluid↗