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PubMed2006

Relationship between metabolism and biomass of medically important zygomycetes.

Little is known about the relationships between metabolic activity and fungal biomass or time of incubation for medically important fungal pathogens. Understanding these relationships may be especially relevant for rapidly growing organisms, such as zygomycetes. A range of inocula of five clinical isolates of zygomycetes (one each of Rhizopus oryzae,Rhizopus microsporus, Cunninghamella bertholletiae, Mucor circinelloides and Absidia corymbifera) were incubated for 6, 8, 12, 24 and 48 h, after which hyphal mass was assessed spectrophotometrically and metabolic activity was measured using various concentrations of XTT and menadione. Both linear regression and the Boltzmann sigmoid model were used and compared for description of relationships between metabolic activity, biomass and time of incubation. Modeling was further applied to eleven additional zygomycete isolates. The relationships of biomass or metabolic activity as a function of time of incubation were well described with the Boltzmann sigmoid model. The latter was superior to linear regression in describing the relationship between metabolic activity and fungal biomass. For all isolates of zygomycetes, increases in metabolic activity preceded increases in biomass. Inter-species differences in growth patterns were observed, with Rhizopus microsporus and Mucor spp. reaching the plateau of growth earlier compared to other species. These findings on the temporal relationship and inter-species differences of hyphal growth and metabolic activity for zygomycetes may be useful in the design and interpretation of in vitro studies of these emerging pathogens.

Humans↗

PubMed1991

Age of onset in siblings concordant for multiple sclerosis.

We have evaluated genetic and environmental influences in multiple sclerosis (MS) by comparing age of onset in 99 sibling pairs concordant for the disease. We used three methods of analysis: (1) comparison of mean differences in age of onset and year of onset, (2) linear regression of differences in age or year of onset vs difference in ages, and (3) intraclass correlation of age of onset which is also used for monozygotic twins concordant for MS. Comparison of the mean differences in age of onset or year of onset is found to be inappropriate and potentially misleading. No significant results were found in linear regression of the age of onset or year of onset vs differences in ages, although a trend towards onset at the same age is present. However, nontwin siblings show a significant intraclass correlation for age of onset (P less than 0.01) as is seen in genetic disorders. A stronger intraclass correlation in age of onset in concordant monozygotic twins vs concordant sibling pairs further suggests that age of onset is partly under genetic control, assuming common exposure to an environmental agent. The results give little support for common exposure to an environmental trigger in concordant MS sibling pairs. They are consistent with a mixture of random independent exposures and common exposures leading to the development of the disease, with the former predominating.

Adolescent↗

PubMedDate not supplied

Neighborhood environment, racial position, and risk of police-reported domestic violence: a contextual analysis.

OBJECTIVES: The purpose of this study was to examine the contribution of neighborhood socioeconomic conditions to risk of police-reported domestic violence in relation to victim's race. Data on race came from police forms legally mandated for the reporting of domestic violence and sexual assault. METHODS: Using 1990 U.S. census block group data and data for the years 1996-1998 from Rhode Island's domestic violence surveillance system, the authors generated annual and relative risk of police-reported domestic violence and estimates of trends stratified by age, race (black, Hispanic, or white), and neighborhood measures of socioeconomic conditions. Race-specific linear regression models were constructed with average annual risk of police-reported domestic violence as the dependent variable. RESULTS: Across all levels of neighborhood poverty (< 5% to 100% of residents living below the federal poverty level), the risk of police-reported domestic violence was higher for Hispanic and black women than for white women. Results from the linear regression models varied by race. For black women, living in a census block group in which fewer than 10% of adults ages > or = 25 years were college-educated contributed independently to risk of police-reported domestic violence. Block group measures of relative poverty (> or = 20% of residents living below 200% of the poverty line) and unemployment (> or = 10% of adults ages > or = 16 years in the labor force but unemployed) did not add to this excess. For Hispanic women, three neighborhood-level measures were significant: percentage of residents living in relative poverty, percentage of residents without college degrees, and percentage of households monolingual in Spanish. A higher degree of linguistic isolation, as defined by the percentage of monolingual Spanish households, decreased risk among the most isolated block groups for Hispanic women. For white women, neighborhood-level measures of poverty, unemployment, and education were significant determinants of police-reported domestic violence. CONCLUSION: When data on neighborhood conditions at the block group level and their interaction with individual racial position are linked to population-based surveillance systems, domestic violence intervention and prevention efforts can be improved.

Adolescent↗

PubMed2001

Assessment of LV systolic function in atrial fibrillation using an index of preceding cardiac cycles.

The clinical assessment of left ventricular (LV) systolic function during atrial fibrillation (AF) is unreliable and difficult because of beat-to-beat variability. We evaluated an index for the estimation of LV systolic function in AF that is based on the relationship between the preceding (R-R1) and prepreceding (R-R2) R-R intervals. LV Doppler stroke volume (SV), ejection fraction (EF), peak aortic flow rate (AoF) and the maximum value of the first derivative of the LV pressure curve (dP/dt(max)) were evaluated in 13 healthy open-chest dogs during triggered AF. All parameters showed a significantly strong positive linear relationship with the ratio of R-R1/R-R2 (r = 0.65, 0.74, 0.75, and 0.70 for SV, EF, AoF, and dP/dt(max), respectively). The calculated value of LV systolic parameters at R-R1/R-R2 = 1 in the linear regression line showed a good relationship and an agreement with the measured average value of the parameter over all cardiac cycles (SV, 12.1 vs. 12.8 ml; EF, 49.6 vs. 51.2%; AoF, 1.37 vs. 1.48 l/min; and dP/dt(max), 2,323 vs. 2,454 mmHg/s). Using the LV systolic parameters estimated at R-R1/R-R2 = 1 in the linear regression line allows the LV contractile function to be accurately and reproducibly evaluated during AF and obviates the less-reliable process of averaging multiple cardiac cycles.

Animals↗

PubMed2006

Asymmetry of retinal arteriolar branch widths at junctions affects ability of formulae to predict trunk arteriolar widths.

PURPOSE: To describe a revised formula for the estimation of retinal trunk arteriole widths from their respective arteriolar branch widths that improves the summarizing of retinal arteriolar diameters. METHODS: A group of young, healthy individuals underwent retinal photography and arteriolar and venular branching points were identified. Vessel widths of the vessel trunks and their branches were determined. The relationship between the branching coefficient (BC; quotient of the area of the branch and trunk vessels) and the asymmetry index (AI) of the vessel branches was explored. The result was used to formulate a new BC. To test the new BC, a second group of young, healthy individuals also underwent retinal photography. Arteriolar branching points were identified, and the trunk and branch arteriolar widths were recorded. This "revised" BC was compared against the gold standard of the BC as a constant value (1.28), as well as a theoretical formula for the BC that includes the angle between the two vessel branches. RESULTS: The BC of arterioles (but not venules) related to the AI (R = 0.275, P = 0.0001; BC arterioles = 0.78 +/- 0.63 . AI). In the second group, the mean arteriolar trunk diameter was 15.56 pixels. The linear regression model for the arteriolar BC was superior to the BC constant of 1.28 (mean difference between estimated and calculated trunk vessel width was 2.16 vs. 2.23 pixels, respectively). The model based on the angle between the branch arterioles was the least accurate (3.43 pixels). CONCLUSIONS: A revised formula has been devised for the arteriolar BC using a linear regression model that incorporates its relationship to the AI. Further studies using this refined formula to calculate the BC are needed to determine whether it improves the ability to detect smaller associations between the retinal vascular network and cardiovascular disease.

Adult↗

PubMed2002

Supplemental nocturnal nasogastric refeeding for better short-term outcome in hospitalized adolescent girls with anorexia nervosa.

OBJECTIVE: Although controversy exists regarding nasogastric refeeding for patients with anorexia nervosa, current methods of inpatient care often result in low discharge weight, a critical risk factor in relapse. This study compared the short-term outcomes of standard oral refeeding and supplemental nocturnal nasogastric refeeding. METHOD: Subjects were 100 hospitalized Caucasian adolescent girls who met DSM-IV criteria for anorexia nervosa. Subjects were partitioned into two groups: oral refeeding (N=48, mean age=15.0 years, SD=1.8) and nocturnal nasogastric refeeding (N=52, mean age=14.8 years, SD=1.9). Unpaired t tests, with Bonferroni correction, were used to compare groups at hospital admission and at discharge. Multivariate linear regression was used to establish the independent effects of nocturnal nasogastric refeeding after adjustment for potential confounding variables. RESULTS: On admission, the groups were comparable in terms of age, weight, and other factors but differed significantly in number of prior hospitalizations (the nocturnal nasogastric refeeding group had more than the oral refeeding group). A series of separate multivariate linear regression models revealed that nocturnal nasogastric refeeding was a significant predictor of weight at discharge and absolute weight gain. CONCLUSIONS: Over a comparable period of time, patients treated with nocturnal nasogastric refeeding had a greater and more rapid weight gain than patients treated with traditional oral refeeding. Supplemental nocturnal nasogastric refeeding was more effective than oral refeeding alone in weight restoration during hospitalization. However, further study is needed on its short-term and long-term effectiveness.

Adolescent↗

PubMed2007

Determination of low tetanus or diphtheria antitoxin titers in sera by a toxin neutralization assay and a modified toxin-binding inhibition test.

A method for the screening of tetanus and diphtheria antibodies in serum using anatoxin (inactivated toxin) instead of toxin was developed as an alternative to the in vivo toxin neutralization assay based on the toxin-binding inhibition test (TOBI test). In this study, the serum titers (values between 1.0 and 19.5 IU) measured by a modified TOBI test (Modi-TOBI test) and toxin neutralization assays were correlated (P < 0.0001). Titers of tetanus or diphtheria antibodies were evaluated in serum samples from guinea pigs immunized with tetanus toxoid, diphtheria-tetanus or triple vaccine. For the Modi-TOBI test, after blocking the microtiter plates, standard tetanus or diphtheria antitoxin and different concentrations of guinea pig sera were incubated with the respective anatoxin. Twelve hours later, these samples were transferred to a plate previously coated with tetanus or diphtheria antitoxin to bind the remaining anatoxin. The anatoxin was then detected using a peroxidase-labeled tetanus or diphtheria antitoxin. Serum titers were calculated using a linear regression plot of the results for the corresponding standard antitoxin. For the toxin neutralization assay, L+/10/50 doses of either toxin combined with different concentrations of serum samples were inoculated into mice for anti-tetanus detection, or in guinea pigs for anti-diphtheria detection. Both assays were suitable for determining wide ranges of antitoxin levels. The linear regression plots showed high correlation coefficients for tetanus (r(2) = 0.95, P < 0.0001) and for diphtheria (r(2) = 0.93, P < 0.0001) between the in vitro and the in vivo assays. The standardized method is appropriate for evaluating titers of neutralizing antibodies, thus permitting the in vitro control of serum antitoxin levels.

Animals↗

PubMed2006

Layover sleep prediction for cockpit crews during transmeridian flight patterns.

INTRODUCTION: Current models of fatigue and alertness use a combination of biological (circadian) and homeostatic factors to predict sleep and wake. Such models do not include social factors in their calculations. The aim of our analysis was to compare the relative contributions of social and biological factors in models designed to predict the total sleep time (TST) during layover periods between transmeridian flights. METHOD: The study actigraphically collected sleep information from 86 cockpit crew (mean age 46.7 yr, SD 4.3 yr) during round-trip patterns from Australia to Los Angeles (n=15), Europe (n=42), New York (n=10), and Hong Kong (n=19). Linear regression models were constructed to predict TST using data from airline schedules. This schedule information included layover length, flight duration, the number of night hours at the destination (social hours), the number of night hours in Australian Eastern Standard time (biological hours), and time zone displacement. These models were then validated using independent data. RESULTS: Analysis indicated that the schedule data was highly correlated. Linear regression analyses indicated that social night hours account for more variance than biological night hours (r = 0.8 vs. 0.7). Additionally, the layover length achieved a correlation coefficient of 0.9. These results were strengthened when the model parameters were applied to the cross-validation dataset. DISCUSSION: Social night hours significantly influence sleep during international layovers and may be a better predictor than biological night hours. More research must be carried out to determine the validity of these findings in a larger, randomly collected flight sample.

Aerospace Medicine↗

PubMed2005

The inverse relationship between thoracic aortic intima media thickness and testosterone level.

BACKGROUND: It is known that testosterone prevents coronary artery disease, and lower testosterone level is a risk factor for ischemic heart disease in men. However, there is no report showing the relationship between testosterone level and severity of thoracic aortic atherosclerosis. AIM: To investigate whether a relationship exists between atherosclerotic thoracic aortic intima media thickness (TAIT) and testosterone level. METHOD: Forty-two male patients (mean age 56 +/- 12 years) without a history of atherosclerotic cardiovascular disease referred for transesophageal echocardiography (TEE) were included. Intima media thickness of aorta was evaluated in each patient by using TEE. Testosterone levels were measured using a commercial kit. Blood chemistry parameters were measured by automated analyzers. The data obtained was evaluated by using correlation analyses and linear regression analysis tests. RESULTS: Mean testosterone values were 507 +/- 209 ng/dl. Testosterone levels showed a negative significant correlation with TAIT (r = -765, p < 0.001). In addition, testosterone levels showed positive correlations with albumin (r = 0.690, p = 0.019) and negative correlations with uric acid (r = -0.630, p < 0.001), HsCRP (r = -0.449, p = 0.003), fibrinogen (r = -0.508, p = 0.001), and white blood cells (r = -0.433, p = 0.005). On the other hand, multiple linear regression analysis showed that TAIT was independently associated with testosterone and uric acid (beta = -0.610, p = 0.002 versus beta = 0.409, p = 0.026 respectively). CONCLUSION: This study indicates that there is an independent relationship between testosterone and TAIT.

Adult↗

PubMed2003

Does cerclage location influence perinatal outcome?

OBJECTIVE: The study was undertaken to measure cerclage location within the cervix and to determine whether placement closer to the internal os is related to perinatal outcome. STUDY DESIGN: We analyzed data collected during a randomized trial of cervical cerclage versus no cerclage that was conducted at Lehigh Valley Hospital between May 1998 and June 2001 in women with ultrasound findings of short cervix less than 25 mm or funneling between 16 and 24 weeks' gestation. Women who were randomly assigned to the cerclage arm had cervical measurements performed before cerclage, including dilation of the internal os, depth of membrane prolapse into the endocervical canal, cervical length below any funnel (distal length), and total cervical length (including any funnel). Measurements obtained after cerclage placement included the distance from external os to cerclage (A), and a repeat of the same four measurements. The distance from the external os to the cerclage (A) was divided by the total cervical length (B) and a cerclage to cervical length ratio (A/B) was calculated. The relationship between these measurements and gestational age at birth was assessed by linear regression analysis. RESULTS: Of 150 patients enrolled, 74 received a McDonald cerclage suture. Mean distal cervical length was 1.9+/-0.9 cm before and 2.9+/-1.0 cm after cerclage (P=.001). The mean distance between the cerclage and external os (A) was 1.8+/-0.6 cm; the total cervical length after cerclage (B) was 3.6+/-0.9 cm. The mean cerclage to cervical length ratio (A/B) was 0.5+/-0.1. Linear regression analysis did not demonstrate a correlation between either the cerclage to external os measurement (A) or the cervical length ratio (A/B) and gestational age at birth (R(2)=0.0006 and 0.008, P=.8 and.6, respectively). CONCLUSION: The length of the cervix below the level of cerclage is not related to duration of pregnancy in women treated with cerclage because of ultrasound evidence of cervical effacement.

Adult↗

PubMedDate not supplied

Gastric emptying characteristics of a novel (13)C-octanoate-labeled muffin meal.

GOALS: Determine the gastric emptying characteristics of a novel, 350-kcal test meal consisting of two muffins, using scintigraphy and the 13C-octanoate breath test (OBT). STUDY: Healthy volunteers underwent three studies on separate days within a 1-week period. On day 1, we measured emptying of the 350-kcal muffin test meal labeled simultaneously with 99mTc sulfur colloid and 13C-octanoate. On day 2, reproducibility of the OBT using a single-labeled 350-kcal test meal was assessed. On day 3, the effect of erythromycin on the 350-kcal OBT was determined. RESULTS: The mean (+/-SD) half-emptying time (T1/2) as measured by scintigraphy was 104 +/- 24 minutes, versus 212 +/- 52 minutes by OBT. There was a strong correlation between T1/2 determined by scintigraphy and the breath test (r = 0.83). Multiple linear regression analysis identified a significant relationship between T1/2 determined by scintigraphy and the 90-and 180-minute breath samples. There was a strong correlation (r = 0.830, slope = 0.732 +/- 0.120 [SE], intercept = 26.4 +/- 12.7) between the T1/2 obtained using the regression equation and the actual T1/2 obtained by scintigraphy. The mean T1/2 (+/-SD) for replicate determinations using the OBT was 209 +/- 52 minutes, compared with 196 +/- 42 minutes on days 1 and 2, respectively (not significant, p = 0.28, paired Student t test). Treatment with erythromycin on day 3 produced a significant decrease in T1/2 (155 +/- 49 minutes, p = 0.002). CONCLUSIONS: The 350-kcal muffin meal OBT provides a convenient, nonscintigraphic way of measuring solid-phase gastric emptying. Multiple linear regression appears promising as a method of analyzing OBT data and may allow for an abbreviated breath test protocol.

Adult↗

PubMed1996

Sciatic function index, nerve conduction tests, muscle contraction, and axon morphometry as indicators of regeneration.

The purpose of this study was to determine which parameters were the best measure of nerve regeneration, assuming that the sciatic functional index (SFI) represented the "gold standard." Three different sciatic functional indexes and 11 commonly used electrophysiologic and morphologic indicators of regeneration were all determined in 24 rats 12 weeks after one of three lesions was created in the sciatic nerve. With linear regression analysis, only fiber/axon diameter ratio (D/d) and myelin thickness/axon diameter ratio showed statistically significant correlations with sciatic functional index (r = 0.55 and 0.53, respectively). The other 11 parameters had poorer correlation. Therefore, if sciatic functional index is the best measure of comprehensive nerve function, then other parameters are not. It is probable that each parameter measures some different component of the regeneration process. A stepwise multiple linear regression analysis produced a model that included D/d, nerve conduction velocity, and nerve action potential amplitude that gave a slightly better correlation (r = 0.67). The relatively poor correlation between sciatic functional index and the other parameters of nerve function indicates that all nerve regeneration studies must be interpreted carefully before comparisons are made. Furthermore, the best measure of nerve function remains unproved or undiscovered in the experimental animal.

Animals↗

PubMed2006

Factors associated with oral health-related quality of life in institutionalized elderly.

OBJECTIVE: The aim of this study was to investigate factors associated with the oral health-related quality of life (OHRQoL) of institutionalized elderly in Germany. MATERIAL AND METHODS: One-hundred-and-fifty-eight subjects from old people's homes were selected (mean 82.8 years). OHRQoL was measured using the Oral Health Impact Profile (OHIP). Denture characteristics (kind and age of denture, retention of removable denture, number of teeth in static occlusion) and general issues (age, gender, education level, and general pain status) were assessed. All factors were subjected to bivariate testing for their effects on the OHIP summary score (OHIP-SC) and to multivariate testing in subjects with removable dentures (n = 128); a linear regression model with backward elimination was used, with OHIP-SC as the dependent variable. RESULTS: In the context of other studies, a median OHIP-SC of 29 indicated highly impaired OHRQoL. According to the bivariate analysis, retention, age of denture, number of teeth in static occlusion, general pain status, and education all exhibited significant influence on OHIP-SC. In the final linear regression model, general pain status, education level, and retention of denture remained at a statistically significant level. The model explained 34% (R2 = 0.34) of the variance of the OHIP-SC. The kind of denture had no significant impact on OHIP-SC. CONCLUSIONS: In contrast to other groups, the kind of denture exhibited little impact on OHIP-SC for this highly specific collective. However, there were functional aspects of dentures which seemed to be important. Non-dental factors had a striking effect on OHRQoL.

Aged↗

PubMed1989

Evaluation of enhanced luminescence immunoenzymometric assays (LIA) for ferritin and free T4.

The Amerlite enhanced luminescence immunoenzymometric assays (LIA) for ferritin and free T4 (FT4) have been evaluated. The LIA assay system employs a two-site binding approach in which one antibody is coated on the interior of plastic microtiter wells and another antibody, or antigen, is tagged with horseradish peroxidase (HRPO). Signal, proportional to the amount of patient analyte, is produced when the HRPO catalyzes the oxidation of luminol resulting in light production. The light signal is increased in magnitude by the incorporation of an enhancing agent which also greatly prolongs the lifetime of the signal. Light production is monitored by an automated luminometer which uses a stored calibration curve to calculate patient results. FT4 within-run coefficients of variation (CVs) ranged from 2.7% to 6.6%; day-to-day CVs from 6% to 15.5% for three levels of control. Sensitivity is 0.03 ng/dl. T3 concentrations up to 8 ng/ml produced no cross-reactivity. Dilutional linearity was exhibited. Lipemia and icterus produced positive interferences. Linear regression analysis of Amerlite and radioimmunoassay (RIA) FT4 values yielded the following values: Amerlite = 0.63 RIA - 0.2, r = .87, n = 79. Ferritin within-run CVs ranged from 4.9% to 10.5%; day-to-day CVs from 5.8-12.5% for three levels of control. Sensitivity is less than 1 ng/ml. Recoveries ranged from 93% to 106% (av. = 99.4%). Dilutional linearity was exhibited. Lipemia caused a positive interference; hemoglobin caused a negative interference. Linear regression analysis of Amerlite and RIA ferritin values yielded the following values: Amerlite = 1.0 RIA + 11.1, r = .96, n = 55.

Bilirubin↗

PubMed1988

Effect of hyaluronic acid on the emergence of neural crest cells from the neural tube of the quail, Coturnix coturnix japonica.

Hyaluronic acid (HA) added to the medium of quail neural tubes explanted in vitro influences the number of migratory neural crest cells that emerge, compared with controls. Neural crest cells were counted with an ocular grid after 20 h of migration into 0.1 mm wide areas or 'bins' lying parallel to the neural tube, and the results were analyzed by linear regression. A low concentration of HA (5 micrograms/ml) significantly decreased the total number of neural crest cells in all bins adjacent to the neural tube, whereas several high concentrations of HA (250, 500, and 1000 micrograms/ml) significantly increased the number of neural crest cells. Intermediate concentrations of HA (50 and 100 micrograms/ml) did not differ from that of controls. Linear regressions of number of cells versus distance from the tube showed no significant differences among the slopes of control, low HA, and high HA treatments, providing evidence that HA does not influence the rate of cell migration. Scanning electron microscopy showed that cells in neuroepithelia exposed to low HA (5 micrograms/ml) appeared in tighter contact, while cells of neuroepithelia in high HA (500 micrograms/ml) appeared more loosely organized, compared with controls. Cells in tight contact could be restrained from leaving the neuroepithelium, whereas cells in loose contact could more readily move out of the neural tube, thus explaining the differences in cell numbers in low HA and high HA, respectively. We conclude that HA can be a factor in the differential adhesivity among neuroepithelial cells and may be important in the initial separation of the neural crest from the neural tube.

Animals↗

PubMed2006

Bone mineral density of the proximal tibia relates to axial torsion in the lower limb.

This study sought to determine the relationship between bone mineral density distribution in the proximal tibia and tibial and femoral torsions, hip-knee-ankle angle, hip rotation index (internal-external rotation), knee abduction moments, and the foot progression angle. Simple linear regression found that the hip rotation index (r=-0.59, p<0.001), tibial torsion (r=-0.41, p=0.004), and knee abduction moments (r=0.39, p=0.005) were significantly related to medial-lateral BMD ratio for all subjects. The three variables were then studied together to determine their relationship to the bone mineral distribution in the proximal tibia using multiple linear regression (r=0.80, p<0.001). These findings suggest that higher medial knee joint loads, loss of internal rotation of the hip, and internal tibial torsion may lead to increased medial versus lateral BMD of the proximal tibia of healthy knees. Similar bone distribution patterns are found in knees with osteoarthritis; therefore, we suggest these may be risk factors.

Adult↗

PubMedDate not supplied

Right ventricular end-diastolic volume index as a predictor of preload status in patients with low right ventricular ejection fraction during orthotopic liver transplantation.

OBJECTIVE: The objective of this study was to compare the accuracy of 2 variables: pulmonary artery occlusion pressure (PAOP) and right ventricular end diastolic volume index (RVEDVI) as predictors of the hemodynamic response to fluid challenge as well as definition of the overall correlation between RVEDVI and change in PAOP, right ventricular ejection fraction (RVEF), central venous pressure (CVP), and determination of the right ventricular function during orthotopic liver transplantation. MATERIALS AND METHODS: A modified pulmonary artery catheter equipped with a fast response thermistor was used to determine RVEF, allowing calculation of RVEF end-diastolic volume index (EDVI, as the ratio of stroke index [SI] to EF). The above-mentioned hemodynamic measures were taken in 4 phases: T0, after induction of anesthesia; T1, during anhepatic phase; T2, 30' after graft reperfusion; and T3, at the end of surgery. RESULTS: The variation of the REF value was 36 +/- 4% and 39 +/- 6%. Linear regression analysis showed a significant correlation between RVEDVI (range, 133 +/- 33-145 +/- 40 mL/m(2)) and stroke volume index (SVI) in each phase (r(2) = 0.49, P < .01; r(2) = 0.57, P < .01) at T0 and T1, respectively, and at T2 and T3 (r(2) = 0.51, P < .01; r(2) = 0.44, P < .01), respectively. No significant variations in the linear regression analysis between RVEDVI, PAOP, CVP, and RVEF were observed. No relationship was found between PAOP (range, 10 +/- 2-6 +/- 2 mm Hg) and SVI. CONCLUSION: RVEDVI may be the best clinical estimate of right ventricular preload. In fact, minor changes of RVEF have been recorded, confirming that RV function was not altered during uncomplicated orthotopic liver transplantation.

Adult↗

PubMed2004

Modeling of bromate formation by ozonation of surface waters in drinking water treatment.

The main objective of this paper is to try to develop statistically and chemically rational models for bromate formation by ozonation of clarified surface waters. The results presented here show that bromate formation by ozonation of natural waters in drinking water treatment is directly proportional to the "Ct" value ("Ctau" in this study). Moreover, this proportionality strongly depends on many parameters: increasing of pH, temperature and bromide level leading to an increase of bromate formation; ammonia and dissolved organic carbon concentrations causing a reverse effect. Taking into account limitation of theoretical modeling, we proposed to predict bromate formation by stochastic simulations (multi-linear regression and artificial neural networks methods) from 40 experiments (BrO(3)(-) vs. "Ctau") carried out with three sand filtered waters sampled on three different waterworks. With seven selected variables we used a simple architecture of neural networks, optimized by "neural connection" of SPSS Inc./Recognition Inc. The bromate modeling by artificial neural networks gives better result than multi-linear regression. The artificial neural networks model allowed us classifying variables by decreasing order of influence (for the studied cases in our variables scale): "Ctau", [N-NH(4)(+)], [Br(-)], pH, temperature, DOC, alkalinity.

Ammonia↗