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PubMed2003

Linear displacement and force induced by polymerization shrinkage of resin-based restorative materials.

PURPOSE: To measure the linear displacement and force induced by polymerization shrinkage of a series of resin-based restorative materials. METHODS: The materials tested were 10 ultrafine midway-filled resin-based composites, mainly used in anterior restorations (Brilliant Dentin, Brilliant Enamel, Charisma F, Pertac II Aplitip, Prodigy, Resulcin, Sculpt-it, Synergy Duo, Tetric and Z100), 11 ultrafine compact-filled composites, suggested by the manufacturers as "amalgam substitutes" for posterior restorations (Alert, Ariston pHc, Definite, EXI-119, EXI-120, Nulite F, Prodigy Condensed, Prodigy High Viscosity, Solotaire, Surefil and Synergy Compact), and six polyacid-modified composites (Compoglass, Dyract, Dyract AP, Elan, F2000 and Hytac Aplitip), also known as compomers. Each property was measured for 180 seconds from the start of curing with the help of custom made devices in eight specimens for each material. Statistical evaluation of the data was performed with one-way ANOVA, Tukey's Studentized Range (HSD) Test (P= 0.05) and simple linear regression. RESULTS: Statistically significant differences among groups and among composites were found for both of the properties that were studied. The ultrafine compact-filled composites (amalgam substitutes) exhibited the least linear displacement, followed by the polyacid-modified composites (compomers) and the ultrafine midway-filled composites, with statistically significant differences among all groups. The groups followed the same order in the polymerization force, with only the compomer-amalgam substitute comparison not being statistically significantly different. The simple linear regression showed that the two studied properties were also highly correlated (r=0.89).

Analysis of Variance↗
PubMed1997

Effects of nedocromil sodium on the oxidative burst of polymorphonuclear leukocytes: comparison with salbutamol.

The effects of nedocromil sodium and of salbutamol on the generation of oxygen-derived free radicals in human polymorphonuclear leukocytes (PMNs) were compared in vitro by the luminol-amplified-chemiluminescence (LACL) assay induced by both particulate (Candida albicans) and soluble formyl-methionyl-leucyl-phenylalanine (fMLP) stimulants. Inhibitory dose-effect linear regressions were observed from 10(-3) to 10(-8) M for nedocromil and salbutamol after a 3' period of incubation with either C. albicans or fMLP. There was a linear regression with nedocromil sodium after 30' incubation, but desensitization was observed with salbutamol after this longer period of incubation. The generation of oxygen-derived free radicals was significantly greater for asthmatic patients than for normal subjects; therefore antiasthmatic drugs with this inhibitory activity could be an extra pharmacological benefit in the treatment of asthmatic patients.

Albuterol↗
PubMed1996

Physicians, pharmaceutical sales representatives, and the cost of prescribing.

OBJECTIVE: To evaluate the influence of primary care physicians' attitudes toward and use of information provided by pharmaceutical representatives on prescribing costs in ambulatory practice. DESIGN: A mailed questionnaire collected information about physician demographic and practice characteristics and attitudes toward and use of information provided by pharmaceutical representatives. PARTICIPANTS: Kentucky physicians practicing primary care adult medicine (family medicine, general practice, general medicine; n = 1603). MAIN OUTCOME MEASURE: Relative cost of prescribing, based on physician responses to treatment choices for ambulatory clinical scenarios in primary care. A multivariable regression model assessed predictive relationships between independent variables and prescription costs. RESULTS: Four hundred forty-six returned questionnaires were suitable for analysis. No significant differences were noted in age, gender, days worked per week, or years since graduation between responders and a sample of nonresponders. A significant positive correlation was found between physician cost of prescribing and perceived credibility, availability, applicability, and use of information provided by pharmaceutical representatives (P < .01, Pearson's Product-Moment Correlation Coefficient). Physicians in academic or hospital-based practice settings had significantly lower prescribing costs than physicians in nonacademic and nonhospital practices (P = .001, analysis of variance). Frequency of use of information provided by pharmaceutical representatives (P = .01, multiple linear regression) and the group practice setting (P = .02, multiple linear regression) remained significant, independent positive predictors of cost in the multivariable regression model. CONCLUSIONS: Frequency of use of information provided by pharmaceutical representatives and the group practice, nonacademic and nonhospital setting may be associated with increased primary care physician prescribing costs.

Attitude of Health Personnel↗
PubMed2005

Catheter-directed MR angiography and cross-sectional imaging for the assessment of renal artery stenosis.

PURPOSE: Catheter-directed intraarterial (IA) gadolinium (Gd)-enhanced gradient-echo (GRE) imaging has been used in the setting of magnetic resonance (MR) imaging-guided endovascular procedures for two-dimensional (2D) or three-dimensional (3D) depiction of blood vessels. In a swine model, the hypothesis was tested that the combination of 2D IA GRE and 2D cross-sectional steady-state free precession (SSFP) imaging improves assessment of renal artery stenosis (RAS) compared with 3D IA GRE imaging alone. MATERIALS AND METHODS: Bilateral RAS was surgically induced in seven pigs. Detection of stenoses was then compared between the combination of 2D projection IA GRE and cross-sectional 2D SSFP imaging without contrast agent and 3D IA GRE alone. Radiographic digital subtraction angiography (DSA) was employed as the reference standard. Linear regression was used to compare stenosis measurements, with an alpha of 0.05. RESULTS: Radiographic DSA and MR imaging were successful in the seven animals (14 stenoses). With use of linear regression analysis, the combination of 2D IA GRE and 2D SSFP imaging had a higher r(2) (0.87 vs 0.72) and a slope closer to unity (1.02 vs 0.77) compared with 3D IA GRE imaging alone. When comparing intercepts, the regression line for SSFP significantly differed from that of 3D IA GRE imaging (P < .05). CONCLUSION: The combination of 2D IA GRE and cross-sectional 2D SSFP imaging improves the accuracy of RAS detection compared with IA 3D IA-GRE alone.

Anatomy, Cross-Sectional↗
PubMed1995

Zinc, biochemical markers of nutrition, and type I osteoporosis.

Having observed previously that the reduction of levels of biological markers of nutrition in postmenopausal osteoporosis may be related to zinc deficiency, we measured plasma and urinary zinc concentrations in 30 women with postmenopausal osteoporosis and in 30 healthy postmenopausal women who served as controls. Plasma zinc levels did not differ between groups, but urinary zinc excretion was significantly higher in the women with postmenopausal osteoporosis (p = 0.002). The relation between total body bone mineral content corrected for body weight (TBBMC/W) and markers of nutrition was significant (multiple regression analysis: p < 0.0001) in the women with postmenopausal osteoporosis but not in the healthy postmenopausal controls. Likewise, the relation between TBBMC/W and plasma and urinary zinc levels also was significant in the women with postmenopausal osteoporosis but not in the controls (multiple regression analysis: p = 0.0022). Neither group showed any correlation between plasma or urinary zinc concentrations and levels of biological markers of nutrition. Urinary zinc concentration correlated significantly with serum tartrate-resistant acid phosphatase level (simple linear regression analysis: r = 0.583, p < 0.001) in the women with postmenopausal osteoporosis but not in controls. TBBMC correlated with urinary zinc concentration significantly in the women with postmenopausal osteoporosis (simple linear regression: r = 0.567, p = 0.0015), but the correlation was nonsignificant in healthy postmenopausal controls. These findings indicate that the elevation of urinary zinc elimination in osteoporosis is dependent on bone resorption.

Aged↗
PubMed2003

A multiple regression model of combined duplex criteria for detecting threshold carotid stenosis and predicting the exact degree of carotid stenosis.

BACKGROUND AND PURPOSE: Combined duplex criteria are commonly used in vascular laboratories for evaluating carotid stenosis. However, most of these combinations are empirical, and systemic validation is lacking. This study was completed using a multiple regression method to evaluate the accuracy of different combined duplex criteria for detecting threshold carotid stenosis and predicting the exact degree of carotid stenosis on angiography. METHODS: Two hundred sixty-six sets of unilateral carotid duplex and angiographic data were randomly divided into 2 sets: a derivation set and a validation set. The derivation set was used to develop a multiple logistic regression model for detecting 70% threshold carotid stenosis. Age, sex, systolic blood pressure, diastolic blood pressure, Doppler peak systolic velocity (PSV), Doppler and diastolic velocity (EDV), the systolic carotid ratio (SCR), and ophthalmic artery flow direction were tested as independent variables. A multiple linear regression model was also developed for predicting the exact degree of carotid stenosis on angiogram. The validation set was then used to evaluate the accuracy of these models. RESULTS: According to the logistic regression strategy, the best multiple logistic regression model was as follows: probability of threshold carotid stenosis = exp(2.6 PSV - 6.2)/[1 + exp(2.6 PSV - 6.2)]. The best linear regression model was as follows: degree of carotid stenosis = 20.2 PSV - 7.4 EDV + 0.4 SCR + 8.5. Both models proved to be valid following an evaluation of the validation set. CONCLUSIONS: This study illustrates that Doppler parameters may be of use in predicting the exact degree of carotid stenosis and the probability of threshold carotid stenosis. This is important if duplex criteria are going to replace angiography as the only tool for selecting endarterectomy candidates.

Aged↗
PubMed2000

Invisible nursing: exploring health outcomes at a global level. Relationships between infant and under-5 mortality rates and the distribution of health professionals, GNP per capita, and female literacy.

AIMS: To explore the relationship between the global distribution of health professionals (physicians and nurses), gross national product per capita (GNP), female literacy and the health outcome indicators of infant, and under-5 mortality rates using available data from United Nations' (UN) sources. To consider the reliability and validity of the variables included, and the implications of the findings for health policy and practice, and for further research. DESIGN: Using a database on 155 countries, regression analyses were performed using GNP, female literacy, numbers of physicians per 1000 population and numbers of nurses per 1000 population as independent variables, and infant mortality (IMR) and under-5 mortality rates (u5MR) as dependent variables. RESULTS: Linear regression analyses give R2 values for the two mortality indicators (IMR and u5MR) of 63% and 66% for physicians and 51% and 52% for nurses. Multiple linear regression analyses reveal a more complex picture. Countries with high ratios of physicians and nurses to population relative to their GNP also tend to show low IMRs and u5MRs. However, when female literacy is included in the model, the majority of these outlying countries move back towards the regression line. Nurses disappear from the model altogether when regressed with physicians, GNP per capita and female literacy for both outcome indicators. CONCLUSIONS: Despite the acknowledged need for caution in the validity and reliability of the UN data sources used in the analyses, interesting positive relationships are identified between the input variables and mortality outputs. The implications for future health policy, practice and research are considered. These include the need for more reliable, comprehensive and up-to-date data sets.

Child, Preschool↗
PubMed2006

Long-term study of intraocular pressure changes in patients with human immunodeficiency virus treated with highly active antiretroviral therapy.

PURPOSE: To characterize a longitudinal relationship between highly active antiretroviral therapy immune recovery as defined by an increase in CD4 cell counts and any associated changes in intraocular pressure (IOP) in both patients with and patients without a history of cytomegalovirus (CMV) retinitis and to determine if human immunodeficiency (HIV)-induced reduction in IOP is reversible. DESIGN: Retrospective analysis of patient data collected from 1997 through 2004. PARTICIPANTS: Cohort of patients from one eye center, including patients from the Longitudinal Study of Ocular Complications of Acquired Immunodeficiency Syndrome. METHODS: Linear regression analyses were conducted within the CMV and non-CMV groups to determine the change in IOP per 100-unit change in CD4 count. Average changes in IOP per change in CD4 count were compared between the CMV and the non-CMV groups using a Wilcoxon rank-sum test. Linear regression analyses were conducted within the CMV and non-CMV groups to determine the linear relationship between the 12-month change in IOP per 12-month 100-unit change in CD4 count. MAIN OUTCOME MEASURE: Intraocular pressure in relation to changes in CD4 cell counts. RESULTS: Compared with the non-CMV group, the median IOP change per change in CD4 count was not statistically different from the CMV group (0.9 vs. 1.7 mmHg/100 CD4 cells, respectively; P = 0.20). Analysis of the linear relationship between the 12-month change in IOP and the 12-month change in CD4 count within both the CMV and non-CMV groups showed a strong linear relationship: 67% of the variability in a 12-month IOP change for the CMV group (P<0.0001) and 36% of the variability in a 12-month IOP change for the non-CMV group (P<0.001). CONCLUSIONS: Reduction in T-lymphocyte count in HIV infection is accompanied by a decrease in IOP in both CMV-infected and non-CMV-infected eyes, and immune recovery is associated with an increase in IOP.

Adult↗
PubMed1999

The poor accuracy of indirect measurements of cadaveric donor kidney weights.

Reports that examined the issue of whether transplantation of inadequate nephron mass may be a risk factor for long-term allograft failure yielded conflicting results. One of the more accurate methods of estimating glomerular mass is kidney weight. Most of the clinical studies used body surface area (BSA) or kidney length as estimates of kidney weight. To test the hypothesis that indirect measures of kidney weight are accurate estimates of kidney weight, we compared the kidney weight of 41 consecutive cadaveric kidneys to donor BSA, dimensions measured with calipers at the time of transplantation, and dimensions supplied by the Organ Procurement Agency (OPA). Linear regression analysis was used with kidney weight as the dependent variable and BSA, kidney length, or kidney volume as the independent variable. Kidney length measured with calipers was also compared to kidney length supplied by the OPA. Kidney weight had the best correlation with kidney volume and kidney length determined by caliper measurements (r = 0.640 and 0.646, respectively). The regression analysis showed that the correlation of kidney weight with BSA was 0.487. The correlation of OPA-provided kidney length with kidney weights was poor (r = 0.410). The linear regression of caliper-measured kidney length versus OPA length yielded a slope of 0.360, instead of an ideal slope of 1. The assumption has been made that kidney weight or a surrogate of kidney weight has an excellent correlation with nephron mass. Some of the variability in studies that attempted to examine the effect of transplanted nephron mass on allograft outcome may be due to inaccurate estimates used for kidney weight. Our data suggest that surrogate measurements of kidney weight may not be accurate. We recommend that measured kidney weight should be used in studies examining the effect of donor renal mass on allograft outcomes.

Body Surface Area↗
PubMed2004

Effect of laser photocoagulation on the retinal vessel diameter in branch and macular vein occlusion.

OBJECTIVE: To investigate the response of retinal vessel diameters to photocoagulation treatment and their role for the success of laser treatment in patients with retinal vein occlusion. METHODS: The study included 14 patients with branch vein occlusion or macular vein occlusion. The ophthalmologic examination included best-corrected visual acuity, biomicroscopy, fundus photography, and fluorescein angiography. Retinal vessel diameters were quantified before and after laser photocoagulation using a retinal vessel analyzer. MAIN OUTCOME MEASURE: Retinal vessel diameters. RESULTS: In cases manifesting macular vein occlusions, no significant change of the vessel diameter in any vessel was observed during the follow-up period. In the group with branch vein occlusion, all vessels tended to constrict after the laser photocoagulation. The effect of laser treatment on retinal vessel diameters was significant for superotemporal (P =.045, analysis of variance [ANOVA]) and inferotemporal branch veins (P =.03, ANOVA). Vasoconstriction was more pronounced in the occluded branch veins (P =.009, ANOVA) compared with the nonaffected veins (P =.12; ANOVA). The change of visual acuity after 3 months was correlated with the change of vessel diameter 3 months after laser treatment for occluded venular branches (r = 0.78, P =.02, linear regression). There was no correlation between the number of laser burns and the change of vessel diameters in the affected veins in this period (r = 0.12, P =.75, linear regression). CONCLUSIONS: Our results show that retinal photocoagulation in patients with branch vein occlusion has a vasoconstrictive effect on occluded veins. The correlation between the change in visual acuity and the change in vessel diameter indicates that branch vein constriction after photocoagulation may be an early indicator of the success of laser treatment.

Aged↗
PubMed1989

Correlation between neuroretinal rim area and age in normal subjects.

The Rodenstock Optic Nerve Head Analyzer was used to study the age distribution of the neuroretinal rim area in 194 eyes of 122 normal subjects aged 7-84 years. No significant linear correlation was found between neuroretinal rim area and age. Linear regression analysis of the neuroretinal rim area in the temporal disc quadrant as a function of age led to the following equation: y = 0.00029x + 0.245; r = 0.052. Linear regression analysis of the neuroretinal rim area in the total disc as a function of age led to the following equation: y = 0.001x + 1.314; r = 0.0053. The 99% confidence limits of the regression slope ranged from -0.0025 to + 0.0045 (temporal disc quadrant) and from -0.00077 to + 0.0013 (total disc), respectively. A nonlinear correlation between neuroretinal rim area and age is very unlikely. Using the Mann-Whitney U-test, no statistically significant difference between the smallest (group of subjects aged 7-19 years) and the largest mean neuroretinal rim area (group of subjects aged 30-39 years) was detectable. From our data we conclude that there are no age-related changes in the neuroretinal rim area as measured with the Optic Nerve Head Analyzer. Changes in the neuroretinal rim area during follow-up examinations of glaucoma suspects may therefore be interpreted as an important sign of early glaucomatous damage. This confirms our previous suggestion that follow-up examinations of the optic disc structure with the Rodenstock Optic Nerve Head Analyzer are useful to confirm the diagnosis of glaucoma, even at a stage where a visual field loss cannot yet be detected by routine perimetry.

Adolescent↗
PubMed2006

Correlation between optic disc area and retinal nerve fiber layer thickness: a study on scanning laser polarimetry with variable corneal compensation.

PURPOSE: To evaluate if a significant increase of the peripapillary retinal nerve fiber layer (RNFL) thickness can be measured in a sample of healthy eyes by means of scanning laser polarimetry with variable corneal compensation (GDx-VCC) as the optic disc (OD) area increases. METHODS: One eye each of 232 healthy subjects (mean age: 57.8 years; range:40-70) was considered. Temporal-superior-nasal-inferior-temporal average (TSNIT Avg) and OD area (area within the ellipse placed on inner border of peripapillary scleral ring) values were collected. Ellipse horizontal and vertical diameters provided on printout were used to estimate OD area using the equation: OD area = pi x horizontal radius x vertical radius. TSNIT Avg values were plotted against OD area and a multiple linear regression including age calculated. RESULTS: Mean OD area was 2.19 mm(2)+/-0.45 (range: 1.23-3.59) and mean TSNIT Avg was 54.3 micro +/- 3.2 (range: 45.8-61.8). Multiple linear regression equation was TSNIT Avg=57.7-0.096 x OD Area-0.055 x Age (Pearson r=-0.146: p=0.086) CONCLUSION: In our sample of healthy eyes, no significant correlation was found between TSNIT Avg and OD area. In spite of a shorter distance between OD and measurement ellipse margins, larger discs did not necessarily show a thicker RNFL. Probably the large inter-subject variability for RNFL thickness, and then for axonal count, was a predominant factor over OD area.

Adult↗
PubMed1999

Circulating levels of interleukin-6, its soluble receptor and interleukin-6/interleukin-6 receptor complexes in patients with type 2 diabetes mellitus.

We evaluated the relationship between plasma fibrinogen concentration and the serum levels of interleukin-6 (IL-6), its soluble receptor, and their complex in patients with type 2 diabetes mellitus. The study comprised 57 patients with type 2 diabetes and 15 normal healthy controls. Serum levels of IL-6, soluble IL-6 receptor (IL-6R), and circulating IL-6/IL-6R complex were determined by enzyme-linked immunosorbent assays. Correlations between the different study parameters and serum IL-6, IL-6R, or IL-6/IL-6R complex levels were determined by multiple linear regression analysis. Any association between the different study parameters and the serum levels of IL-6, IL-6R, or IL-6/IL-6R complex were determined by stepwise linear regression analysis. The serum IL-6 level in diabetic subjects was significantly higher than in normal healthy controls (3.48 +/- 3.29 pg/ml vs 0.784 +/- 0.90 pg/ml, mean +/- SD, respectively, P = 0.0001). The specific optical density of the serum IL-6/IL-6R complex in diabetic patients was also significantly higher than in normal healthy controls, although there was no significant difference in the serum IL-6R level between diabetic patients and controls. The serum IL-6 concentration was correlated significantly with the HbA(1C) level (beta = 0.58, P = 0. 04) by multiple regression analysis. Stepwise regression analysis revealed that the levels of serum IL-6 (F = 8.251), HbA(1C) (F = 1. 08), and serum urea nitrogen (F = 5.603) were associated with the plasma fibrino gen concentration. These results suggest that hyperglycaemia and increased levels of serum IL-6 can increase the plasma fibrinogen concentration, one of the known risk factors for atherosclerosis in patients with type 2 diabetes mellitus.

Adult↗
PubMed2002

The impact of antihypertensive drug groups on urinary albumin excretion in a non-diabetic population.

AIMS: Microalbuminuria (30-300 mg 24 h-1) is recognized to be independently associated with renal and cardiovascular risk. Antihypertensives may lower microalbuminuria. We questioned whether the use of different antihypertensive drug classes in general practice influences microalbuminuria as related to blood pressure in nondiabetic subjects. METHODS: To study this, we used the data from 6836 subjects of an on-going population based study, focused on the meaning of microalbuminuria (PREVEND). Odds ratios, adjusted for age, sex, blood pressure, cholesterol level, smoking and the use of other antihypertensive or cardiovascular drugs, were calculated to determine the association of drug groups with microalbuminuria. Influence of antihypertensives on the relation between blood pressure and (log) urinary albumin excretion was determined by comparing linear regression lines. RESULTS: Microalbuminuria was significantly associated with the use of dihydropyridine calcium channel blockers (odds ratio: 1.76 [1.22-2.54]), but not with other antihypertensive drug groups. The linear regression line of the relation between blood pressure and (log) urinary albumin excretion was significantly steeper (P = 0.0047) for users of calcium channel blockers, but not for other antihypertensives, compared with subjects using no antihypertensive. Users of a combination of renin-angiotensin system inhibitors and diuretics however, had a less steep regression line (P = 0.037). CONCLUSIONS: This study suggests a disadvantageous effect of dihydropyridine calcium channel blockers on microalbuminuria compared with other antihypertensive drug groups. Thus, if microalbuminuria is causally related to an increased risk for cardiovascular morbidity and mortality, dihydropyridines do not seem to be agents of choice to lower blood pressure. Furthermore, the combination of renin-angiotensin system inhibition and diuretics seems to act synergistically.

Adult↗
PubMed2005

Use of lithium dilution and pulse contour analysis cardiac output determination in anaesthetized horses: a clinical evaluation.

OBJECTIVE: To assess the suitability of a human algorithm for calculation of continuous cardiac output from the arterial pulse waveform, in anaesthetized horses. STUDY DESIGN: Prospective clinical study. ANIMALS: Twenty-four clinical cases undergoing anaesthesia for various conditions. MATERIALS AND METHODS: Cardiac output (Qt), measured by lithium dilution (QtLiDCO), was compared with a preceding, calibrated Qt measured from the pulse waveform (QtPulse). These comparisons were repeated every 20-30 minutes. Positive inotropes or vasopressors were administered when clinically indicated. Cardiac indices from 30.7 to 114.9 mL kg(-1) minute(-1) were recorded. Unusually shaped QtLiDCO curves were rejected and the measurement was repeated immediately. RESULTS: Eighty-nine comparisons were made between QtLiDCO and QtPulse. The bias between the mean (+/-SD) of the two methods (QtLiDCO - QtPulse) was -0.07 L minute(-1)(+/-3.08) (0.24 +/- 6.48 mL kg(-1) minute(-1)). The limits of agreement were -12.72 and 13.2 mL kg(-1) minute(-1) (Bland & Altman 1986; Mantha et al. 2000). Linear regression analysis demonstrated a correlation coefficient (r2) of 0.89. Cardiac output in individual patients varied from 49.1 to 183% of the initial measurement at the time of calibration. Linear regression of log-transformed Qt variation for each method found a mean difference of 9% with limits of agreement of -4.1 to 22.1%. CONCLUSIONS AND CLINICAL RELEVANCE: This method of pulse contour analysis is a relatively noninvasive and reliable way of monitoring continuous Qt in the horse under anaesthesia. The ability to easily monitor Qt might decrease morbidity and mortality in the anaesthetized horse.

Anesthesia, General↗
PubMed2002

Renal copper as an index of copper status in marginal deficiency.

Marginal copper (Cu) deficiency is difficult to study, in part because its effects may be small, but also because feeding of a deficient diet may not cause a discernable change in Cu status. The key to resolution of effects may be in the choice of Cu status index. In this study, liver Cu concentration, a commonly used index of Cu status, was compared with activity of ceruloplasmin (CP), a circulating Cu-dependent enzyme, and kidney Cu concentration for their utility in resolving effects of marginal Cu deficiency. Seventy male, weanling rats were fed diets containing, nominally, 0, 1.5, 3, 4.5, or 6 mg Cu/kg diet for 5 wk. All three indices showed strong depression with severe deficiency (dietary Cu=0), but were relatively weak in their ability to distinguish between animals fed marginally deficient diets when compared by group statistics (ANOVA). Further, group statistics revealed no effect of marginal deficiency on six other variables known to change with severe Cu deficiency: heart weight/body weight, hematocrit, red cell distribution width, neutrophil count, glycated hemoglobin, and platelet count. To take into account interanimal variation, the three putative indices were plotted against these six variables and linear regression was performed on points representing marginally deficient rats. None of the variables showed significant regression with liver Cu or serum ceruloplasmin, but three showed significant regression with kidney Cu. These findings indicate that kidney Cu is preferable to liver Cu or ceruloplasmin as an index of Cu status in marginal deficiency and that linear regression is a possible way of testing for effects of marginal Cu deficiency, especially when effects are subtle.

Analysis of Variance↗
PubMed1994

[The distribution of gene frequencies of immunoglobulin allotype G2m(23) factor in Chinese populations].

The distribution of G2m(23) gene frequencies in eight Chinese populations, which cover three ethnic groups, was studied by enzyme linked immunosorbent assay inhibition test. According to the results of multiple linear regression and multiple liner correlation there exists a cline of G2m(23) gene frequencies along with the height and latitude in China. In addition, an equation of multiple linear regression which can be used to expect the G2m(23) gene frequencies in some Chinese populations was established. Some possible reasons for this cline were also discussed.

Asian People↗
PubMed2003

Simulation of aerated lagoon using artificial neural networks and multivariate regression techniques.

The aim of this study was to develop an empirical model that provides accurate predictions of the biochemical oxygen demand of the output stream from the aerated lagoon at International Paper of Brazil, one of the major pulp and paper plants in Brazil. Predictive models were calculated from functional link neural networks (FLNNs), multiple linear regression, principal components regression, and partial least-squares regression (PLSR). Improvement in FLNN modeling capability was observed when the data were preprocessed using the PLSR technique. PLSR also proved to be a powerful linear regression technique for this problem, which presents operational data limitations.

Biotechnology↗