Association between vitamin d deficiencies in sarcoidosis with disease activity, course of disease and stages of lung involvements

Background: Despite negative association between 25-hydroxy vitamin D and incidence of many chronic respiratory diseases, this feature was not well studied in sarcoidosis. Current study investigated the association between 25-hydroxy vitamin D deficiency with sarcoidosis chronicity, disease activity, extra-pulmonary skin manifestations, urine calcium level and pulmonary function status in Iranian sarcoidosis patients. Results of this study along with future studies, will supply more effective programs for sarcoidosis treatment. Methods: Eighty sarcoidosis patients in two groups of insufficient serum level and sufficient serum level of 25-hydroxy vitamin D were studied. Course of sarcoidosis was defined as acute and chronic sarcoidosis. Pulmonary function test (PFT) was assessed by spirometry. Skin involvements were defined as biopsy proven skin sarcoidosis. 24-hour urine calcium level was used to specify the disease activity. Stages of lung involvements were obtained by CT-scan and chest X-ray. The statistical analyses were evaluated using Statistical Package for the Social Sciences. Results: A significant negative correlation was obtained between vitamin D deficiency in sarcoidosis patients and disease chronic course and stages two to four of lung involvements. Considering other parameters of the disease and vitamin D deficiency, no significant correlation was detected. Conclusions: In conclusion, results of the current study implies in the role of vitamin 25(OH)D deficiencies in predicting the course of chronic sarcoidosis. Furthermore, it was concluded that vitamin 25(OH)D deficiency can direct pulmonary sarcoidosis toward stage 2–4 of lung involvements

Approximate Confidence Bounds For Ratios Of Variance Components In Two-Way Unbalanced Crossed Models With Interactions

Consider the general unbalanced two-factor crossed components-of-variance model with interaction given by Yijk=μ+Ai+BjCij+Eijk (i - 1,2, …a; j=1,…b; k = 1,.. n ij \u3e 0) Ai,Bj,Cij and Eijkare independent unobservable random variables. Also Ai~N(0,(0,σ2B), Cij~N(0,σ2C) and Eijk~N(0,σ2E). In this paper approximate confidence bounds are obtained for ρA= σ2A/σ2 and ρB= σ2B/σ2 (where σ2= σ2A+σ2B+σ2C + σ2E) for special cases of the above model. The balanced incomplete block model is studied as a special case. © 1991, Taylor & Francis Group, LLC. All rights reserved

Confidence Intervals On Individual Variances In Two-Way Models

Approximate confidence bounds on individual variances for unbalanced two-way crossed models are obtained. A simulation study was done to check the effectiveness of the approximate bounds, and to compare the proposed bounds with the cell mean procedure proposed by Srinivasan from the Colorado State Un. in her Ph.D. Thesis. Balanced incomplete block (BIB) designs are used as a special case of designs with empty cells, and confidence bounds on the variances are constructed for various design configurations. © 1992

A Statistical Approach To The Configuration Interaction Problem

A new statistical approach to the configuration interaction problem is proposed. It will potentially reduce the size of CI vectors significantly and thus alleviate one of the main hindrances to doing very large CI calculations. This method will also provide us with statistical confidence limits on lower and upper bounds. These confidence bounds are qualitative different from mathematically more rigorous lower bounds discussed elsewhere. The approach is discussed and possible algorithms presented. © 1991

Length Biased Density Estimation Of Fibres

Cox (1969) discussed several procedures used in sampling of textile fibres. One such procedure is called length biased or weighted sampling and occurs when the chance of selection is proportional to fibre length. Cox considered the problem of estimating the unweighted distribution function Fat a fixed x \u3e 0 and compared the asymptotic variance of estimators based on length biased samples with those based on unweighted samples. Consideration here is devoted to estimating the probability density function f at a fixed x \u3e 0 based on length biased samples.It is shown, under suitable regularity conditions, that thesquare of the bias of the weighted estimator is less (greater) than the square of the bias of the Parzen (1962)-Rosenblatt (1956) kernel estimator of f(x) based on unweighted observations when (f\u27(x)/x)(f(2)(x)+f\u27(x))\u3c 0(\u3e0) and n is sufficiently large. Moreover, the variance of the length biased estimator isless (greater) than that of the unweighted estimator when x \u3e μ(x \u3c μ) for allnsufficiently large, where μ denotesthe mean with respect to f. An optimal window width hn((x) is given which makes the asymptotic meansquare error of the length biased estimator a minimum. Under regularity assumptions, it is shown thatthe optimal asymptotic mean square error of the lengthbiased estimator at x is less than that for the unweighted estimator exactly when (μ/x)3|g(2)(x)/f(2)(x)| 1. Moreover, simulations are undertaken to compare the two estimators for several sample sizes. © 1991, Taylor & Francis Group, LLC. All rights reserved

CD4:CD8 ratio: A valuable diagnostic parameter for pulmonary sarcoidosis

Sarcoidosis is a multi-organ disease and is characterized by sarcoidal noncaseating granuloma comprised of T-helper/inducer (CD4+) lymphocytes and scant cytotoxic (CD8+) T-lymphocytes. CD4+:CD8+ T-cell elevated ratio is a characteristic diagnostic parameter for sarcoidosis. This is the first report from Iran evaluating the CD4:CD8 ratio capability in differentiating pulmonary sarcoidosis from other interstitial lung diseases (ILDs) on a large cohort. Fifty pulmonary sarcoidosis patients and 50 non-sarcoidosis interstitial lung diseases (nsILDs) patients were included in the current study. Bronchoalveolar lavage (BAL) was performed using flexible fiberoptic bronchoscopy and flow cytometer. Non-sarcoidosis group was established by 50 components that were classified into eight subgroups. Fifty-two percent of sarcoidosis patients and 62% of non-sarcoidosis interstitial lung disease patients had normal spirometric results. The CD4/CD8 ratio was significantly higher in sarcoidosis than in non-sarcoidosis interstitial lung diseases (p 3.5 in 33.3%, 2.5-3.5 in 7.1%, 1.5-2.5 in 20.2% and < 1.5 in 39.4% of the entire study population. The best cut off point was 1.1 with the sensitivity of 92% and specificity of 80% for distinguishing sarcoidosis from other interstitial lung diseases. Performing bronchoalveolar lavage as the safe and rapid first step confirms the diagnosis of sarcoidosis in 92% of cases (current study sensitivity). Hence, performing an invasive procedure was required in a few patients only. Bronchoalveolar lavage flow cytometry in the assessment of clinical and radiological findings supplies an appropriate diagnostic adjunct for discriminating sarcoidosis from non-sarcoidosis interstitial lung diseases