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PubMed1993

[The assessment of nutrient value of vegetables].

The criterion for the nutrient value of vegetables ist their specific contribution to the nutrition of man, whereby particular emphasis must be placed on vitamin C, carotene, raw fibre, calcium and iron. The contents of these constituents have been summarized as "factor of essential nutritive value". The metabolic processes and other biochemical transformations, however, require a dynamical consideration of the mentioned factor with regard to the changing nutrition components. In review of the dependence of quality changes on storage temperature (teta) and storage period in days (xi) a model is presented demonstrating a "dynamical factor of the essential nutrient value WNF (teta:xi) "for different vegetable crops. It is supplemented by the corresponding regression functions and nomograms for its calculation, which emanate from the degree of quality of product at the moment of harvesting. For quickly perishable vegetables WNF (teta:xi) decreased by up to 27%. Species which store well as well as favourable storage conditions produced significantly lower decreases. Introducing a dynamical assessment of the nutritive value may contribute to a preciser rating of the physiological value of vegetables.

Ascorbic Acid↗
PubMed1989

Evaluation of three methods for determining initial vancomycin doses.

Dosing methods proposed by Matzke et al., Moellering et al., and Lake and Peterson were used to predict initial doses of vancomycin for serum concentration simulation using a two-compartment open model. Previously reported pharmacokinetic data from 25 of 28 patients were used to simulate steady-state serum vancomycin concentrations for doses derived from the three methods. The Matzke method failed to provide simulated one-hour postinfusion levels less than 30 micrograms/mL in 48 percent and troughs greater than 5 micrograms/mL in more than 88 percent of the patients. The Moellering method succeeded in achieving this goal in 96 percent of the simulated one-hour levels, and in 72 percent of the troughs when a six-hour dosing interval was selected. For the 8 mg/kg Lake-Peterson doses, one-hour levels greater than 30 micrograms/mL occurred in 28 percent of the simulations, and for the 10 mg/kg doses this increased to 40 percent. The 8 mg/kg doses resulted in trough simulations less than 5 micrograms/mL in 28 percent and the 10 mg/kg reduced this to only 20 percent. These simulations indicated that the Moellering nomogram with the six-hour dosing interval was the most successful method for initial dose selection, but early serum concentration monitoring and adjustment of initial empirical and nomogram-derived doses is necessary to assure safe and effective vancomycin serum concentrations.

Analysis of Variance↗
PubMed1998

A preoperative nomogram for disease recurrence following radical prostatectomy for prostate cancer.

BACKGROUND: Few published studies have combined clinical prognostic factors into risk profiles that can be used to predict the likelihood of recurrence or metastatic progression in patients following treatment of prostate cancer. We developed a nomogram that allows prediction of disease recurrence through use of preoperative clinical factors for patients with clinically localized prostate cancer who are candidates for treatment with a radical prostatectomy. METHODS: By use of Cox proportional hazards regression analysis, we modeled the clinical data and disease follow-up for 983 men with clinically localized prostate cancer whom we intended to treat with a radical prostatectomy. Clinical data included pretreatment serum prostate-specific antigen levels, biopsy Gleason scores, and clinical stage. Treatment failure was recorded when there was clinical evidence of disease recurrence, a rising serum prostate-specific antigen level (two measurements of 0.4 ng/mL or greater and rising), or initiation of adjuvant therapy. Validation was performed on a separate sample of 168 men, also from our institution. RESULTS: Treatment failure (i.e., cancer recurrence) was noted in 196 of the 983 men, and the patients without failure had a median follow-up of 30 months (range, 1-146 months). The 5-year probability of freedom from failure for the cohort was 73% (95% confidence interval = 69%-76%). The predictions from the nomogram appeared accurate and discriminating, with a validation sample area under the receiver operating characteristic curve (i.e., comparison of the predicted probability with the actual outcome) of 0.79. CONCLUSIONS: A nomogram has been developed that can be used to predict the 5-year probability of treatment failure among men with clinically localized prostate cancer treated with radical prostatectomy.

Adult↗
PubMed1980

Nomographic estimation of time to reach steady-state serum concentration during phenytoin therapy.

The time to reach steady-state on phenytoin therapy depends on the dose and the pharmacokinetic parameter of the individual patient. A nomogram is presented to help the physician to decide whether a measured serum concentration of phenytoin can be regarded as being within 20% of the steady-state level. The nomogram is based on the pharmacokinetic parameters of phenytoin reported for adult patients.

Humans↗
PubMed1979

Correction for the presence of cross-reactants in saturation assays: application to thyroxine cross-reactivity in 3,3',5'-(reverse)-triiodothyronine radioimmunoassay.

Cross-reaction of anti-3,3',5'-triiodothyronine (rT3) antisera with thyroxine has proved problematical in the development of radioimmunoassays for rT3. Results of experimental work with two antisera with differing specificities are presented which illustrate certain aspects of cross-reacting assay systems. The mathematical theory of a single binding-site, two ligand assay is discussed and extended by use of a multiple binding-site computer model to a two binding-site, two ligand system. It is suggested that for the practical evaluation of the nature and extent of cross-reaction, a family of response curves for the hormone should be drawn, each curve representing the addition of a fixed mass of the cross-reactant to a set of standard incubation mixtures. Such curves will reveal whether the antiserum is (a) specific, implying that assay results require no correction, (b) behaves as a single binding site system, in which case measurement of the relative potency of the two ligands at the point on the response curve generated by the serum sample will enable an algebraic correction to be made, given that the T4 concentration is known or (c) behaves as a multiple binding-site system where correction necessitates the use of a nomogram.

Binding Sites, Antibody↗
PubMed2001

[Integral parameters of electrocardiogram: perfection of assessment].

The role of such parameter as electric quality of the heart (EQH) is assessed by a biophysical analysis of a new model of dipolic equivalent electric generator of the heart taking account of myocardial inductivity in the course of excitation. How to estimate EQH by standard ECG parameters using calculated nomogram is shown. Results of EQH estimation in the course of treatment are provided.

Adult↗
PubMed2003

The alteration of urine composition due to stone material present in the urinary tract.

OBJECTIVES: Based on a recently introduced mathematical model approach we show that uroliths located in the urinary tract (UT) can substantially deplete the urinary concentrations of lithogenic constituents by continuous growth. METHODS: To illustrate the influence of the urinary depletion effect on urinalysis, a "typical" calcium oxalate (CaOx) stone former, presently not stone-free, was investigated. Serum and urine samples were analyzed. Several metabolic tests were performed. Crystallization risk according to the BONN-Risk-Index (BRI) and the relative supersaturation in respect to CaOx (RS(CaOx)) were determined. X-ray films taken before and after a period of six months were evaluated in order to estimate stone size and average stone growth rate taken place within that period. RESULTS: Regarding CaOx urolithiasis the urine samples show a pathologically altered pH, a low 24h-citric acid excretion, and a low 24h-urine volume. Neither calcium nor oxalate excretion data reflect values indicating these substances as risk factors. However, BRI and RS(CaOx) reflect a high crystallization risk. The patient's intestinal oxalate absorption is high. Applying the depletion model, the patient's 24h-urine composition shifts from normooxaluric to hyperoxaluric. CONCLUSION: In the patient, a hitherto undetected hyperoxaluria is diagnosed when in-vivo stone growth is taken into account. This is a clear indication that the metabolic status can only be evaluated correctly in "stone-free" patients. Any stone material present in the UT must be considered in urinalysis interpretation as the stone-related urinary depletion effect is of high clinical relevance. A helpful nomogram is presented, allowing the estimation of the extent of urinary depletion caused by CaOx uroliths.

Adult↗
PubMed1995

Astigmatism reduction clinical trial: a multicenter prospective evaluation of the predictability of arcuate keratotomy. Evaluation of surgical nomogram predictability. ARC-T Study Group.

OBJECTIVE: To determine the accuracy of the Lindstrom surgical nomogram for astigmatism. DESIGN: A prospective multicenter study. PATIENTS: One hundred sixty eyes of 95 patients underwent astigmatic keratotomy in eight centers by nine surgeons. Inclusion criteria for the study included age of at least 18 years with 1 to 6 diopters (D) of naturally occurring corneal astigmatism and less than 1 D of lenticular astigmatism. INTERVENTIONS: A standardized astigmatic keratotomy surgical technique was performed on each eye. Surgical measurements were determined using the Lindstrom surgical nomogram for astigmatism. MAIN OUTCOME MEASURE: The Holladay, Cravy, Koch vector analysis method was used to determine the change in refractive cylinder results. Refractive changes also are presented without vector analysis merely using the absolute change in refractive cylinder and axis. RESULTS: Multiple regression analysis was used to develop a mathematical model determining the factors predictive of the change in refractive cylinder. The significant predictors for the amount of astigmatic correction achieved were, in order of decreasing importance, the following: number of incisions (R2 = 30%), incision length (R2 = 16%), age (R2 = 8%), and gender (R2 = 2%). CONCLUSIONS: Astigmatism is a two-dimensional measurement of both quantity and direction that is most appropriately analyzed with vector analysis. The original Lindstrom surgical nomogram for arcuate keratotomy used in this study is still quite useful although it tended to underpredict results for many patients, especially those having two incisional surgeries. Some older subjects having minimal surgery achieved greater correction than predicted by the original nomogram. The most important factors predictive of greater astigmatic keratotomy surgical effect are incision number, incision length, older age, and male gender.

Adult↗
PubMed1993

Discrete subaortic stenosis. Operative age and gradient as predictors of late aortic valve incompetence.

Between January 1969 and May 1990, 100 patients were operated on for discrete subaortic stenosis. Three patients died in the perioperative period. Patients with intrinsic lesions, prosthetic replacement, or extensive operative remodeling of the aortic valve were excluded from the analysis. The 67 remaining patients had a median follow-up of 62 months. Preoperatively, 8 patients had aortic valve competence, 51 had mild incompetence, and 8 patients moderate aortic valve incompetence. At follow-up mild incompetence persisted in 27 and moderate incompetence in 6 patients. In 1 patient it worsened from no incompetence to mild and in another patient from mild to moderate. The probability of aortic incompetence at follow-up was significantly and simultaneously related (multivariate ordinal logistic model) to (1) older age at operation (logarithm of months, p = 0.007), (2) higher preoperative gradient (third power of milligrams of mercury, p = 0.0004), (3) preoperative cardiomegaly (p = 0.04), and (4) surgical myectomy (p = 0.002). There was an interaction between age and gradient (p = 0.03). Two nomograms are proposed as a generalizable aid to decision making. The data support the policy of early repair of subaortic stenosis.

Adolescent↗
PubMed2003

The role of human glandular kallikrein 2 for prediction of pathologically organ confined prostate cancer.

BACKGROUND: In recent studies serum levels of human glandular kallikrein 2 (hK2) demonstrated significant differences in pathologically organ-confined versus non-organ-confined prostate cancer (PCa). In this study we investigated whether hK2 adds independent information when considered together with traditionally used parameters to predict organ confined (pT2a/b) PCa. METHODS: Serum levels of hK2, total and free prostate-specific antigens (PSA) were obtained one day before radical prostatectomy in 245 consecutive men. These were included with clinical stage and biopsy Gleason grade into univariate analysis and multivariate logistic regression models. RESULTS: pT2a/b PCa was found in n = 148 patients. In univariate analysis all preoperative parameters demonstrated significant association with the presence of pT2a/b PCa. Using multivariate logistic regression model hK2 (P = 0.022), clinical stage (P < 0.0001), and Gleason grade (P < 0.0001) were independent predictors of pT2a/b PCa whereas PSA (P = 0.3) was not. In bootstrap corrected logistic regression based nomograms the addition of hK2 density marginally enhanced predictive accuracy when PSA, PSA density, clinical stage, and Gleason grade were considered (AUC = 0.879 without hK2 density and 0.883 with hK2 density). CONCLUSIONS: hK2 and hK2 density could independently predict pT2a/b PCa. However, improvement in predictive accuracy was marginal when nomograms based on traditional variables were complemented with this serum marker.

Area Under Curve↗
PubMed1992

Color Doppler determination of regurgitant flow: from proximal isovelocity surface areas to proximal velocity profiles. An in vitro study.

There is not yet a completely satisfactory Doppler method for determining the severity of valvular regurgitation. Recently, interest has focused on the so-called "flow convergence region." Color Doppler provides a longitudinal velocity profile of the flow convergence region proximal to restrictive orifices. With respect to determination of regurgitant flow rate, we studied the influence of orifice flow rate and orifice size on the proximal velocity profile. In a phantom model, flow across circular orifices was studied. The distance r (v) of discrete velocities detected proximal to the orifice was measured along the flow center line. Velocity profiles were established. (1) Proximal isovelocity surfaces: The radius r (v) also represented the central radius of the proximal isovelocity surfaces. Increases in flow resulted in larger central radii r (v). Application of the continuity equation and analysis of the resulting values yielded a radius and an orifice size dependence of the geometric isovelocity surface shape. Therefore, their surface area and flow rate could not be calculated from these axial measurements alone. (2) Proximal velocity profiles: The resulting hyperbolic velocity profile curves (x axis = velocity [v], y axis = distance [r (v)]) are shifted rightward by increases in flow. In contrast, increases in orifice size make the curve steeper, but large r (v) are not affected. This differential influence of flow rate and orifice size allows orifice size independent determination of flow rate. A nomogram is presented as one possible method for flow determination.

Blood Circulation↗
PubMed2002

Population pharmacokinetics of digoxin in pediatric patients.

Digoxin pharmacokinetics were studied in a pediatric population with an age range of 6 days to 1 year using the population pharmacokinetic approach. Digoxin data were analyzed by mixed-effects modeling according to a one-compartment steady-state pharmacokinetic model using NONMEM software. The final model selected for the population prediction of digoxin clearance in pediatric patients was as follows: [equation: see text] Individual empirical Bayesian estimates were generated on the basis of the population estimates and were used to correlate the optimum dose of digoxin and patient age according to the following equation: [equation: see text] This equation and its derived nomogram may be used for the initial dosing of digoxin in children aged between 0 and 1 year. The use of this nomogram in routine monitoring requires further pharmacokinetic and clinical validation.

Algorithms↗
PubMed2003

Blood pressure nomograms for school children in Iran.

Currently there are no blood pressure (BP) nomograms based on local data available in Iran. In order to obtain data on BP distribution in Iranian school children, 8848 children aged 7-12 years were studied in Tehran. BP was found to increase with age. Both systolic and diastolic BP showed a positive correlation with height and weight in both sexes. The systolic and diastolic BP in boys and girls were not significantly different. As the sample was representative of Iranian school children, reference standard curves were constructed by modeling data using fractional polynomial. The 50th and 95th percentiles of systolic and diastolic BP of Iranian children were compared for each age with the results reported in the study of the Second Task Force. These percentiles were different from the Second Task Force study. Environmental and genetic determinants are likely to be responsible for the differences. The differences show that the use of local BP nomograms is necessary for assessing the BP levels in Iranian children.

Aging↗
PubMed1976

Evaluation of serum ionic calcium measurement in a general hospital population.

Direct measurement of ionic calcium was evaluated in light of conflicting reports concerning the correlation of ionic calcium with total calcium and ionic calcium as predicted from total calcium and serum protein. Ionic calcium in the sera of normo- hypo-, and hypercalcemic adult hospitalized patients was measured anaerobically using an Orion model 98-20 calcium flow-thorugh electrode. Good correlation (r = .77) was found with the calculated ionic calcium value derived from total protein and total calcium, using the McLean-Hastings nomogram. Good correlation was also present between the measured ionic and total calcium (r = .80). In view of these correlations, the introduction of serum ionic calcium measurements into the general hospital laboratory repertoire is of questionable value.

Calcium↗
PubMed1983

[Experimental studies with a new Giessen model high frequency jet ventilator].

In some critically ill patients respiratory can be maintained by high frequency jet ventilation. Gas exchange and transport by this method cannot be explained exactly up to date. Therefore it is impossible to compare this method with classical IPPV. Statistics and nomograms must be prepared for common clinical use.

Humans↗