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PubMed1989

Assessment of progression of chronic renal failure--using reciprocal of serum creatinine.

Twenty-seven patients with chronic renal failure (CRF) were studied over a period of 6 to 57 months. The mean serum creatinine (Scr.) was 4 mg/dl. All patients were started on conservative therapy. The rate of progression of renal failure was assessed by least square linear regression analysis using reciprocal of Scr. (1/Scr.) versus time plots. Group I (13 patients) showed steady progression to end-stage renal failure (mean slope 0.013328). 7 of 13 patients had chronic glomerulonephritis. 11 had nephrotic proteinuria. In group II (14 patients), the regression line remained static indicating arrest of progression of renal disease (mean slope 0.0087858). 6 of 14 had nephrosclerosis. 3 had nephrotic proteinuria. We conclude that (1) assessment of progression of CRF by linear regression analysis of 1/Scr. vs time is a useful method. (2) persistent nephrotic proteinuria is an adverse longterm risk factor. (3) conservative therapy has a definite role in the management of CRF.

Adolescent↗
PubMed1995

Sodium-retaining activity of some natural and synthetic 21-deoxysteroids.

The effect of progesterone and six other C21-deoxysteroids on renal sodium retention by male adrenalectomized rats was compared with the effect exerted by the natural corticoids aldosterone, 11-deoxycorticosterone, and corticosterone. Steroids were active in the following order: aldosterone > 11,19-oxidoprogesterone > 5 alpha H-3,20-pregnanedione > or = 5 beta H-3,20-pregnanedione > progesterone = 11-ketoprogesterone > 6,19-oxidoprogesterone = 11-keto-6,19-oxidoprogesterone > or = corticosterone. All C21-deoxysteroids, except 11,19-oxidoprogesterone, exhibited parabolic log dose-response functions, indicating an effect that opposes renal sodium retention at high doses. 11,19-Oxidoprogesterone and the natural corticoids exhibited normal, exponential, log dose-response curves. Diverse geometric parameters related to molecular planarity were calculated and their correlation with biopharmacological properties was attempted. The best linear regression was obtained for correlation of the concavity of log dose-response parabolas (second-order coefficients) of C21-deoxysteroids with the C3 = O/ring D angle of these molecules. A good linear regression could also be obtained for correlation of the affinity of C21-deoxysteroids, except 11,19-oxidoprogesterone, for purified type I mineralocorticoid receptors with those angles. The latter correlation deteriorated upon incorporation of the affinity data for the three natural corticoids, due to similar affinities of these hormones for type I mineralocorticoid receptors, but could be restored when the binding data for the unpurified, corticosterone-binding globulin-containing stage of the receptors were considered. In vivo binding data followed the same trend as that for unpurified receptors.

Adrenal Glands↗
PubMed2003

School league tables: a new population based predictor of dental restorative treatment need.

AIM: To test whether dental restorative treatment need was related to the school league tables and level of social deprivation of the school ward. DESIGN: An ecological study using clinical data aggregated at school level, collected in the school dental screening examinations (1996-97), National Census (1991) and the results of the UK school league tables--Key Stage 2 SATs (1996-97). SETTING: State primary schools in the Greenwich District of SE London, UK (1996-97). SUBJECTS: 12,854 pupils (6-11 years of age) in 62 schools. OUTCOME MEASURE: The percentage of 6 to 11 year old pupils per school requiring dental restorative treatment. RESULTS: Deprivation as measured by the overall Jarman Under Privileged Area Index (UPA) of the school ward was not associated with dental restorative treatment need (p > 0.05). Only two components of the Jarman Index, level of unemployment and the number of lone parent families in the school ward were found to be significantly associated with dental restorative treatment need (p < 0.05). Results of stepwise multiple linear regression analysis showed that the association with the school league table results in all three subjects, English, Mathematics and Science remained statistically significant after adjusting for levels of unemployment and single parents. Results of multiple linear regression analysis showed that a high level of dental restorative treatment need was significantly associated with poor school league table results in English, Mathematics and Science (p < 0.05) after adjusting for the overall Jarman score of the school ward. A separate analysis for the 11-year-old pupils aggregated by school (n = 46 schools) gave similar results. CONCLUSIONS: Aggregate measures of academic achievement may be a potential indicator of dental restorative treatment need.

Child↗
PubMed1998

Hyperhomocysteinemia increases intimal hyperplasia in a rat carotid endarterectomy model.

PURPOSE: This preliminary study investigated the ability to elevate the serum homocysteine (H[e]) levels and investigated the increases in postoperative neointimal hyperplasia (IH) in an environment with hyperhomocysteinemia and the resultant restenosis in a rat carotid endarterectomy (CEA) model. METHOD: The 9 rats for the control group were fed rat chow, and the 8 rats for the H(e) group were fed H(e)-supplemented rat chow for 2 weeks before and after CEA. The animals underwent anesthesia, and a left common CEA was performed. After 14 days, the serum H(e) levels were measured and the left carotid artery was harvested and elastin stained. Morphometric measurements were used to calculate the area of stenosis of the lumen. The mean and the standard deviation of the mean were determined. The 2 groups were compared with the Mann-Whitney test and a linear regression model. Three additional rats per group were studied, with carotid artery sectioning with double immunohistochemical staining for 5-bromodeoxyuridine (BrdU) and alpha-smooth muscle (alpha-SM) actin. RESULTS: The serum H(e) level in the H(e) group was 36.32 micromol/L +/- 15.28, and in the control group the level was 5.53 micromol/L +/- 2.06 (P =.0007). IH presented as percent lumen stenosis was 21.89% +/- 4.82% in the H(e) group and 4.82% +/- 1.64% in the control group (P =.0007). The linear regression model of the serum H(e) levels and the percent stenosis showed a linear relationship (r2 =.72). The alpha-SM actin staining revealed that nearly all of the cells in the IH area were of smooth muscle or myofibroblast origin and that 10.1% +/- 2.6% of the cells were stained for BrdU in the control group versus 23% +/- 7.1% in the H(e) group. Also, 9.3% +/- 2.6% of the cells in the IH area were stained for BrdU and for alpha-SM actin versus 19.1% +/- 5. 6% stained for both BrdU and alpha-SM actin in the H(e) group. CONCLUSION: This is the first study to examine IH after CEA and hyperhomocysteinemia in rats. The study shows that the elevation of serum H(e) levels can be obtained by feeding rats modified diets with added H(e). The consistent elevation of serum H(e) levels was associated with more than 4 times the amount of IH after a CEA in a rat model.

Animals↗
PubMed2003

Prostate-specific antigen as an estimator of prostate volume in the management of patients with symptomatic benign prostatic hyperplasia.

OBJECTIVES: To assess the ability of serum prostate specific antigen (PSA) to estimate prostate volume (PV) to aid in the management of patients with benign prostatic hyperplasia (BPH). METHODS: From 1989 to 2002, data were collected from 2264 patients complaining of lower urinary tract symptoms (LUTS) who visited the Department of Urology of the University Medical Centre Nijmegen, The Netherlands. Baseline PV and serum PSA was determined using standard techniques. All patients who had a baseline PV < or =200 ml, as well as a baseline serum PSA 0-10 ng/ml, were included. Patients with a history of prostate surgery, prostate cancer and conditions other than BPH at baseline were excluded. A log-transformed linear regression model was used to estimate PV. Receiver-operating characteristic (ROC) curves were constructed to evaluate the ability of serum PSA to estimate threshold PVs in men with BPH, and to select the optimal serum PSA cut-off values. RESULTS: The analyses included 1859 patients with a mean age of 63.5 years, mean baseline PV 43.9 ml, and mean baseline PSA value 3.1 ng/ml. PV as well as serum PSA increases with age. Linear regression analyses showed that PV and serum PSA have an age-dependent log-linear relationship, where 42% of the variance of PV can be explained by PSA and age. ROC's area under the curves (AUC) reveal that PSA has a good predictive value for assessing 'prostate enlargement', with AUC around 82% in the overall age groups irrespective of the PV cut-off values. Optimal serum PSA cut-off values for the overall study population irrespective of age are 2.0 ng/ml to detect PV >30 ml and 2.5 ng/ml to detect PV >40 ml. CONCLUSIONS: This study suggests that serum PSA can estimate prostate enlargement sufficiently accurately to be useful for therapeutic, especially medical, management. It is well accepted that the outcome of pharmacotherapy for BPH depends on baseline PV. Therefore, in the absence of reliable direct measurement of PV, serum PSA determination may be used to optimise patient management.

Adult↗
PubMed2005

Low-density lipoprotein cholesterol estimation by a new formula in Indian population.

BACKGROUND: Estimation of low-density lipoprotein cholesterol is crucial in the management of ischemic heart disease patients. Low-density lipoprotein cholesterol is routinely calculated in laboratories world over by applying Friedewald formula for logistic reasons. We derived a new formula based on multiple regression approach. METHODS: Lipid profiles were done on blood samples of 2008 patients. In initial 1000 patients, low-density lipoprotein cholesterol was estimated by a direct method and also by Friedewald formula. By applying linear regression methods on the data of direct estimation method, a new formula was obtained and the accuracy of this new formula was validated in the next 1008 patients. RESULTS: The mean low-density lipoprotein cholesterol was 116+/-41.5 mg/dl (3.02+/-1.08 mmol/l) measured by direct low-density lipoprotein cholesterol assay and that calculated by Friedewald formula was 119+/-46 mg/dl (3.09+/-1.2 mmol/l) for the initial 1000 patients. Low-density lipoprotein cholesterol measured by direct low-density lipoprotein cholesterol assay and calculated from Friedewald formula showed good correlation (r = 0.88), however, there was minimal overestimation by the Friedewald formula. The correlation improved between direct low-density lipoprotein cholesterol and calculated low-density lipoprotein cholesterol after excluding the patients with triglycerides more than 350 mg/dl (r = 0.92). The mean low-density lipoprotein cholesterol measured by the direct assay and by new formula in the next 1008 patients was 117+/-40 mg/dl (3.04+/-1.04 mmol/l) and 113.7+/-37 mg/dl (2.96+/-0.96 mmol/l), respectively with very good correlation (r = 0.97) between them. CONCLUSIONS: The new formula derived from multiple linear regression analysis appears to be more accurate than Friedewald formula in Indian population.

Algorithms↗
PubMed2006

Relationship between insulin sensitivity and in vivo mitochondrial function in skeletal muscle.

Recent data have shown that individuals with low insulin sensitivity (S(I)) also have reduced whole body maximal oxygen uptake. The objectives of this study were to determine 1) whether muscle mitochondrial function was independently related to S(I) after being adjusted for known determinants of S(I) and 2) whether lower S(I) among African-American (AA) vs. Caucasian-American (CA) women was due to lower muscle mitochondrial function among AA women. Subjects were 37 CA and 22 AA premenopausal women (age: 33.6 +/- 6.3 yr). Mitochondrial function [time constant of ADP (ADP(tc))] was assessed during a 90-s unilateral isometric contraction using (31)P magnetic resonance spectroscopy, S(I) with an intravenous glucose tolerance test, body composition by dual-energy X-ray absorptiometry, and visceral adipose tissue (VAT) with computed tomography. ANOVA was used to compare AA and CA groups, and multiple linear regression modeling was used to identify independent predictors of S(I). Between-race comparisons indicated that muscle oxidative capacity was lower among AAs vs. CAs (ADP(tc): 25.6 +/- 9.8 vs. 21.4 +/- 9.9 s). Multiple linear regression models for the dependent variable S(I) contained 1) VAT and race and 2) VAT, race, and ADP(tc). Significant independent effects for all predictor variables were observed in both the first (r(2) = 0.345) and second (r(2) = 0.410) models. The partial correlation for race was lower in the second model (-0.404 vs. -0.300), suggesting that muscle mitochondrial function contributed to the racial difference in S(I). Lower muscle mitochondrial function among AAs may in part explain lower S(I) among them.

Absorptiometry, Photon↗
PubMed2002

Resource utilization for acute lower gastrointestinal hemorrhage: the Ontario GI bleed study.

OBJECTIVES: Acute lower gastrointestinal hemorrhage (LGIH) is a common indication for hospitalization. However, there are few published studies of related health care resource utilization. Resource utilization, length of stay (LOS) and direct medical costs were characterized in a cohort of patients admitted for nonmalignant LGIH to centres in Ontario. METHODS: Consecutive admissions for LGIH were identified at four Ontario hospitals. Profiles of resource utilization, LOS and estimates of direct medical costs were compiled through detailed chart review and adaptation of an administrative database. All centres were participants in the Ontario Case Cost Project. Linear regression models of log-transformed data were constructed to identify demographic variables predictive of LOS and case cost. RESULTS: Among 124 patients enrolled (mean age 58.8 years) the average case cost was dollars 4832 (SD dollars 7187) for 7.5 days in hospital (SD 12.0). Diverticular disease was the bleeding source most often identified (34.6%), followed by hemorrhoids (13.7%) and ischemic colitis (9.7%). Older age and comorbid illness, specifically coronary artery disease (CAD), were associated with both increased LOS and higher case cost in univariate regression analyses. Age persisted as the lone independent predictor of LOS in the multivariate model (P<0.05, R2=0.076), and age and CAD were both independent predictors of cost (P<0.05, R2=0.109) in a stepwise multiple linear regression analysis. Neither sex nor nonsteroidal anti-inflammatory drug use predicted LOS or cost. CONCLUSIONS: Admissions for acute LGIH are associated with significant resource utilization, particularly among elderly patients with CAD.

Acute Disease↗
PubMed2005

Bone mineral density in subjects using central nervous system-active medications.

PURPOSE: Decreased bone mineral density defines osteoporosis according to the World Health Organization and is an important predictor of future fractures. The use of several types of central nervous system-active drugs, including benzodiazepines, anticonvulsants, antidepressants, and opioids, have all been associated with increased risk of fracture. However, it is unclear whether such an increase in risk is related to an effect of bone mineral density or to other factors, such as increased risk of falls. We sought to examine the relationship between bone mineral density and the use of benzodiazepines, anticonvulsants, antidepressants, and opioids in a representative US population-based sample. SUBJECTS AND METHODS: We analyzed data on adults aged 17 years and older from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). Total femoral bone mineral density of 7114 male and 7532 female participants was measured by dual-energy x-ray absorptiometry. Multivariable linear regression models were used to quantify the relation between central nervous system medication exposure and total femoral bone mineral density. Models controlled for relevant covariates, including age, sex, and body mass index. RESULTS: In linear regression models, significantly reduced bone mineral density was found in subjects taking anticonvulsants (0.92 g/cm2; 95% confidence interval [CI]: 0.89 to 0.94) and opioids (0.92 g/cm2; 95% CI: 0.88 to 0.95) compared with nonusers (0.95 g/cm2; 95% CI: 0.95 to 0.95) after adjusting for several potential confounders. The other central nervous system-active drugs--benzodiazepines or antidepressants--were not associated with significantly reduced bone mineral density. CONCLUSION: In cross-sectional analysis of NHANES III, anticonvulsants and opioids (but not benzodiazepines or antidepressants) were associated with significantly reduced bone mineral density. These findings have implications for fracture-prevention strategies.

Adolescent↗
PubMed1990

Prediction of postoperative intraocular lens chamber depth.

The postoperative intraocular lens (IOL) chamber depth was predicted using a multiple linear regression analysis of the postoperative chamber depth as a function of the corneal height, the preoperative chamber depth, and the axial length in 279 patients with a posterior chamber lens implant. Based on a linear regression formula incorporating these preoperatively defined parameters, the postoperative IOL chamber depth could be predicted with a correlation coefficient of 0.71 and an error of +/- 0.30 mm (SD). It is concluded that an individual prediction of the IOL chamber depth will improve the accuracy in IOL calculation.

Aged↗
PubMed2001

Association between serum triiodothyronine (t3) level and risk of disease recurrence in men with localized prostate cancer.

We assessed the relationship of serum triiodothyronine (t3) level and risk of disease recurrence in men treated for localized prostate cancer. Participants in our study were found through urology and radiation oncology clinics, and all eligible patients were asked to take part. All patients had been initially diagnosed on the basis of rising prostate specific antigen (PSA) or abnormal physical examination. Histological confirmation of diagnosis was obtained for all subjects. Serum (t3) level was determined by chemoluminescent assay with a standard, commercially available instrument (Immulite Diagnostic Products Corporation, Los Angeles, California). Sixty-eight men with prostate cancer were studied. In our treatment protocol, patients are divided into three risk groups: low risk: serum PSA</=10, stage</=T2a, or Gleason grade</=6. These patients are treated with a radioactive implant; moderate risk: serum PSA 10-15 or Gleason 7 or stage</=T2b. These patients are treated with 3 months of combined hormonal therapy followed by an implant; high risk: Gleason >7, tumor in seminal vesicle biopsy, serum PSA >15 or stage T2c or T3. These patients are treated with 3 months combined hormonal therapy, an implant, and after 2 months break 6000 rad external beam radiotherapy. There was a significant increase in serum t3 with risk category (P=0.011). Tukey's multiple range B-test showed a significant difference between the t3 levels of the high risk patients, when compared to the t3 levels of the moderate (P=0.013) and low risk patients (P=0.041). The range test showed no significant difference between the t3 levels of the moderate and low risk patients (P=0.897). Because t3 levels may be affected by age, we performed multivariate linear regression, with t3 as the dependent variable. There was a statistically significant (P=0.035) association of t3 level with risk group, but there was no significant association of t3 with age (P=0.803). Multivariate linear regression, with t3 as dependent variable, PSA, Gleason score, and stage as independent variables showed a significant overall association of the three independent variables with t3 (P=0.042), though individually the relationships were not significant. None of the men had a t3 level that was above the normal range for our laboratory (137 ng/dl). Urologists are actively seeking additional biomarkers of prostate cancer aggressiveness. Many prostate cancers are quite indolent and may never cause a problem, but it is impossible to identify such tumors with certainty. Further studies of serum t3 level as a biomarker in prostate cancer might therefore be worthwhile. With more and better biomarkers, many older men might be spared the rigors of radiation therapy and/or surgery and the complications. Also, new prostate cancer therapies might be directed toward inhibiting the mitogenic effects of t3.Prostate Cancer and Prostatic Diseases (2001) 4, 232-234.

Journal Article↗
PubMed1991

Neuroepithelial bodies stimulate proliferation of airway epithelium in fetal hamster lung.

Autoradiographs were prepared from lungs of a newborn Syrian golden hamster exposed continuously to [3H]thymidine throughout the final 4.5 days of gestation. Silver grains were counted over nuclei of 1,145 nonendocrine airway epithelial cells adjacent to 28 mature neuroepithelial bodies (NEBs). Generally, accumulated label was greater in cells nearer a NEB than in those further away. Diminution of label with increasing distance from the closet NEB was confirmed statistically. In 24 of 28 instances, both rank-order correlation and linear regression were significant (P less than 0.001-0.05); in two others, only one test was significant; in another two, neither test was significant. The pattern was consistent and widespread. Rank-order correlations and linear regressions were significant (P less than 0.001) in populations pooled separately from left lung, right upper, and right lower lobes, and the three regression lines were superimposable. Confirmation was obtained in another animal by labeling S-phase cells with a 2-h transplacental pulse of bromodeoxyuridine (BrdU) on fetal day 15. Of 322 BrdU-positive cells counted in 270,204 microns 2 of bronchial epithelium, 174 (54%) lay within 20 microns of a neuroepithelial body. This concentration of dividing cells was significant by chi-square test: chi 2[1] = 101.62; P less than 0.001. We conclude that established NEBs promote growth of the developing airway by stimulating proliferation of local endoderm. A few daughter cells may enter NEBs; most move away to join the expanding nonendocrine airway lining.

Animals↗
PubMed2004

Lower capillary density but no difference in VEGF expression in obese vs. lean young skeletal muscle in humans.

Obesity is associated with lower skeletal muscle capillarization and lower insulin sensitivity. Vascular endothelial growth factor (VEGF) is important for the maintenance of the skeletal muscle capillaries. To investigate whether VEGF and VEGF receptor [kinase insert domain-containing receptor (KDR) and Flt-1] expression are lower with obesity, vastus lateralis muscle biopsies were obtained from eight obese and eight lean young sedentary men before and 2 h after a 1-h submaximal aerobic exercise bout for the measurement of VEGF, KDR, Flt-1, and skeletal muscle fiber and capillary characteristics. There were no differences in VEGF or VEGF receptor mRNA at rest between lean and obese muscle. Exercise increased VEGF (10-fold), KDR (3-fold), and Flt-1 (5-fold) mRNA independent of group. There were no differences in VEGF, KDR, or Flt-1 protein between groups. Compared with lean skeletal muscle, the number of capillary contacts per fiber was the same, but lower capillary density (CD), greater muscle cross sectional area, and lower capillary-to-fiber area ratio were observed in both type I and II fibers in obese muscle. Multiple linear regression revealed that 49% of the variance in insulin sensitivity (homeostasis model assessment) could be explained by percentage of body fat (35%) and maximal oxygen uptake per kilogram of fat-free mass (14%). Linear regression revealed significant relationships between maximal oxygen uptake and both CD and capillary-to-fiber perimeter exchange. Although differences may exist in CD and capillary-to-fiber area ratio between lean and obese skeletal muscle, the present results provide evidence that VEGF and VEGF receptor expression are not different between lean and obese muscle.

Adult↗
PubMed2006

Comparison of methods for calculating prostate specific antigen velocity.

PURPOSE: Prostate specific antigen velocity is frequently calculated using regression analysis of multiple prostate specific antigen measurements during an interval of 18 to 24 months. It has been reported that the prostate specific antigen velocity in the year before prostate cancer diagnosis is associated with the cancer specific mortality rate following radical prostatectomy and radiation therapy. There are limited data comparing alternate methods of calculating prostate specific antigen velocity. In this study we compared simple arithmetic prostate specific antigen velocity calculations to the more complicated regression analysis using prostate specific antigen measurements from varying intervals to determine whether the methods were interchangeable. MATERIALS AND METHODS: From 2003 to 2005 a total of 540 men underwent radical retropubic prostatectomy for localized prostate cancer. Preoperative prostate specific antigen velocity was calculated using arithmetic and linear regression methods during 12 and 18-month intervals. The correlation, mean and median prostate specific antigen velocity were compared among methods. RESULTS: Prostate specific antigen velocity calculations using simple arithmetic and linear regression had a strong correlation when restricted to prostate specific antigen values from 12 months before diagnosis (r = 0.92). When prostate specific antigen measurements beyond 1 year were included in the calculation, prostate specific antigen velocity was significantly lower than in the 12 months before cancer diagnosis. CONCLUSIONS: Using a simple arithmetic prostate specific antigen velocity calculation yields results comparable to those of the more complicated regression analysis when restricted to prostate specific antigen values from within the year before diagnosis in patients with clinically localized prostate cancer. In this manner arithmetic prostate specific antigen velocity calculations may be used in daily clinical practice to help predict the outcome following definitive therapy. Prostate specific antigen velocity is significantly lower when calculated during a longer interval before prostate cancer diagnosis.

Disease Progression↗
PubMed1991

Alternative method of gestational age assessment by the measurement of human erythrocyte differentiation antigen expression.

Standard estimates of gestational age are dependent on such subjective data as maternal recollection of last menstrual period, ultrasound examination of the fetus, and the postnatal physical and neurological examination (Ballard score). We hypothesized that a quantitative, objective laboratory test using flow cytometric analysis of erythroid differentiation antigens could be useful to predict gestational age. For this study erythrocyte samples were obtained within 24 hours of birth from 25 infants (gestational ages 20 to 41 weeks) who met the criteria that traditional estimates of gestational age, such as the Ballard score, fetal ultrasound, and maternal estimate of last menstrual period all agreed within 1 week for the assessed infant's gestational age. Study measurements included reticulocyte count and determination of the percentage of erythrocytes that expressed the 5F1 and 20.3 erythropoietic differentiation antigens. Linear regression analysis indicated that the best correlations with gestational age were reticulocyte count (R2 = .354) and the reciprocal of the percentage of erythrocytes expressing the 5F1 antigen (R2 = .470). When both variables were incorporated into a linear regression model, the predictability of gestational age achieved an R2 = .608. Through this study we have established the feasibility and methodology of using fetal and newborn erythrocytes to provide an objective assessment of gestational age by flow cytometric analysis of erythroid differentiation antigen expression. This methodology will allow for an independent assessment of gestational age when fetal blood sampling is performed for other prenatal diagnostic studies. Further investigation is needed to identify other erythroid differentiation markers that would improve the accuracy of our model to predict gestational age.

Antigens, Differentiation↗
PubMedDate not supplied

Fractional wavelet analysis for the simultaneous quantitative analysis of lacidipine and its photodegradation product by continuous wavelet transform and multilinear regression calibration.

Fractional wavelet transform (FWT) was applied to the original absorption spectra of lacidipine (LAC) and its photodegradation product (LACD), and the resulting FWT spectra were processed by continuous wavelet transform (CWT) and multilinear regression calibration (MLRC) for the simultaneous quantitative analysis of both products in their binary mixtures. These methods do not require any chemical separation step and chemical complex reaction to obtain a detectable signal for the degradation product. By using the Mexican hat function, 2 calibration functions for LAC and LACD were obtained by measuring the CWT transformed signals at 416.1 nm for LAC and 414.6 nm for LACD, after FWT processing of the original absorption spectra. The calibration graphs were linear in the concentration range of 5.08-40.64 microg/mL for LAC and 0.51-8.16 microg/mL for LACD. The limit of detection and the limit of quantitation were found to be 0.289 and 0.956 microg/mL for LAC and 0.036 and 0.118 microg/mL for LACD, respectively. For comparison, the MLRC algorithm was applied to the linear regression functions for the individual drug and its photoproduct. In this approach, a set of linear regression functions was obtained from the relationship between concentrations and FWT signals in the wavelength range 411.0-412.4 nm. Both methods were applied to the quantitative evaluation of LAC and LACD in laboratory and pharmaceutical samples, and produced very satisfactory results.

Algorithms↗
PubMed2004

The effect of maintenance immunosuppression medication on the change in kidney allograft function.

BACKGROUND: The optimum maintenance immunosuppression regimen for kidney transplant recipients is uncertain. In this study we determined the effect of maintenance immunosuppression medications on the rate of kidney allograft function loss defined by the annualized change in glomerular filtration rate (GFR). METHODS: We studied 40,963 first kidney only transplant recipients between 1987 and 1996 with allograft survival of at least two years in the United States Renal Data System. Linear regression methods were applied to serial GFR estimates after transplantation to determine the annualized change in GFR. Patients were classified according to the type of maintenance calcineurin and purine metabolism inhibitor received after transplantation. Multiple linear regression was used to determine the independent effect of maintenance immunosuppression medications on the annualized change in GFR (mL/min/1.73m2/year). RESULTS: Compared to patients who received cyclosporine microemulsion (Neoral), a slower decline in GFR was observed in tacrolimus-treated patients (1.60 mL/min/1.73m2/year, 95% CI 1.22-1.97, P < 0.001) and patients who did not receive calcineurin inhibitors (0.82 mL/min/1.73m2/year, 95% CI 0.08-1.56, P= 0.03). In contrast, compared to compared to patients who received Neoral, a faster decline in GFR was observed in patients who received the original oil-based formulation of cyclosporine (Sandimmune) (-0.16 mL/min/1.73m2/year, 95% CI -0.003 to -0.32, P= 0.04) and patients with unknown calcinuerin inhibitor exposure (-2.11 mL/min/1.73m2/year, 95% CI -2.27 to -1.95, P < 0.001). Compared to patients who received azathioprine, patients who received mycophenolate mofetil (MMF) had a slower decline in GFR (0.61 mL/min/1.73m2/year, 95% CI 0.14-1.08, P= 0.01) and patients with unknown purine metabolism inhibitor exposure had a faster decline in GFR (-0.61 mL/min/1.73m2/year, 95% CI -0.75 to -0.47, P < 0.001.) In a subgroup analysis of patients who received a transplant after 1993, the decline in GFR was slower for tacrolimus compared to neoral treated patients (1.64 mL/min/1.73m2/year, 95% CI 1.15-2.14, P < 0.001) but was not different for MMF compared to azathioprine-treated patients (0.24 mL/min/1.73m2/year, 95% CI -0.38-0.85, P= 0.45). CONCLUSION: Tacrolimus and MMF were the calcineurin inhibitor and purine metabolism inhibitor associated with the most favorable effects on rates of change in allograft function. Because most transplant recipients establish a low baseline level of allograft function, the effect of immunosuppression medication on GFR decline should be considered when selecting a maintenance immunosuppression regimen.

Adolescent↗
PubMed1998

Application of the concise exposure index (OCRA) to tasks involving repetitive movements of the upper limbs in a variety of manufacturing industries: preliminary validations.

A summary of eight investigations is presented, which were carried out using standardized methods, for the purpose of quantifying exposure to tasks involving repetitive movements of the upper limbs, as well as quantifying the prevalence of work-related musculoskeletal disorders (WMSDs) of the upper limbs in groups of exposed workers. A total of 462 exposed workers were examined, and the study also took into account the data pertaining to a matched reference group comprising 749 workers not exposed to any specific occupational risk. Regarding the quantification of exposure to increased risk, use was made of a concise index (OCRA index), proposed by Occhipinti, in this issue. The data resulting from the eight investigations were used for the study of measurements and models of association among the exposure variables (mainly represented by the OCRA index), as well as the effect variables represented by the prevalence of the various WMSDs of the upper limbs taken both individually and jointly. Significant associations were reported between the OCRA index and an effect indicator represented by the prevalence of all the WSMDs of the upper limbs, calculated on the number of upper limbs at risk. When a logarithmic conversion of the relative exposure (OCRA) and injury indices was carried out, a simple linear regression model resulted that seems to provide a satisfactory predictive performance of the risk of WMSDs of the upper limbs, based on the exposure index. The study confirmed the efficacy of various other models designed to predict effects based on multiple linear regression functions, in which the independent variables are represented by both the OCRA exposure index and by parameters relative to the breakdown by gender and age of the groups of exposed workers.

Arm↗