Nadeem Shafique Butt

A Class of Weighted Weibull Distribution

The weighted Weibull model is proposed following the method of Azzalini (1985). Basic properties of the distribution; including moments, generating function, hazard rate function and estimation of parameters; have been studied.

The Four-Parameter Burr XII Distribution: Properties, Regression Model and Applications

ABSTRACT This paper introduces a new four-parameter lifetime model called the Weibull Burr XII distribution. The new model has the advantage of being capable of modeling various shapes of aging and failure criteria. We derive some of its structural properties including ordinary and incomplete moments, quantile and generating functions, probability weighted moments, and order statistics. The new density function can be expressed as a linear mixture of Burr XII densities. We propose a log-linear regression model using a new distribution so-called the log-Weibull Burr XII distribution. The maximum likelihood method is used to estimate the model parameters. Simulation results to assess the performance of the maximum likelihood estimation are discussed. We prove empirically the importance and flexibility of the new model in modeling various types of data.

Simulation Study to Compare the Random Data Generation from Bernoulli Distribution in Popular Statistical Packages

In study of the statistical packages, simulation from probability distributions is one of the important aspects. This paper is based on simulation study from Bernoulli distribution conducted by various popular statistical packages like R, SAS, Minitab, MS Excel and PASW. The accuracy of generated random data is tested through Chi-Square goodness of fit test. This simulation study based on 8685000 random numbers and 27000 tests of significance shows that ability to simulate random data from Bernoulli distribution is best in SAS and is closely followed by R Language, while Minitab showed the worst performance among compared packages.

Infrequent Immunohistochemical Expression of Napsin A in Endometrial Carcinomas.

Introduction: Many studies described napsin A as a specific diagnostic marker that aids in differentiating lung adenocarcinomas from other respiratory tumors. This study describes the expression phenotype of napsin A in endometrial neoplasms, it investigates the relationship between this expression profile and the clinicopathologic parameters, and assess its utilization as an independent predictive marker. Methods: A total of 76 cases of previously diagnosed endometrial carcinoma (including 53 endometrioid adenocarcinomas, 6 endometrioid adenocarcinomas with squamous differentiation, 9 serous adenocarcinomas, 6 clear cell adenocarcinomas, and 2 malignant mixed mullerian tumors) and 30 tissue samples of noncancerous endometrium (including 16 proliferative endometriums, 10 secretory endometriums and 4 endometrial polyps) were retrieved from the archives of Pathology Department at King Abdulaziz University, Jeddah, Saudi Arabia. For napsin A detection, tissue microarrays and immunostaining were used. Results: A total number of 12 (15.78%) cases were positive for napsin A immunostaining. Brown granular cytoplasmic expression of napsin A was detected in 9.4% of endometrioid adenocarcinomas, 16.7% of endometrioid adenocarcinomas with squamous differentiation, 22.2% of papillary serous endometrial carcinomas, and 66.7% of clear cell carcinomas. Three (10%) control cases showed similar granular cytoplasmic expression. Positive napsin A immunostaining was more frequent in clear cell carcinoma, and there is a significant association between positive napsin A immunostaining and clear cell carcinoma (P-value=0.007). Significant associations have been found also between napsin A expression and older ages (above 60 y) and higher stage (IVB), the P-values of which were 0.035 and 0.043, respectively, but not with the tumor recurrence or survival rate. Conclusions: Although napsin A is infrequently expressed in endometrial carcinomas, positive results of napsin A immunostaining in endometrial neoplasms might support the diagnosis of clear cell carcinoma when the pathologic differential diagnosis includes other histologic subtypes.

Cyclin D1 is significantly associated with stage of tumor and predicts poor survival in endometrial carcinoma patients

Cyclin D1 overexpression has been described to have oncogenic role and association with diagnosis, prognosis and survival in various tumors. This study will describe the immunohistochemical phenotype of cyclin D1, and investigate the correlation between these patterns of expression and clinicopathological parameters of endometrial carcinomas, to conclude the clinical relevance of cyclin D1 expression in the evolution of endometrial neoplasms. This study employed 101 endometrial tissue samples which include 71 endometrial carcinomas and thirty normal and benign endometrium cases. All these tissue samples were used in the assembly of tissue microarrays which have been utilized afterward in immunohistochemistry staining to detect cyclin D1 expression. Forty (56.3%) cases of endometrial carcinomas showed brown nuclear expression of cyclin D1 including 36 (61%) cases of endometrioid carcinomas, and 3 (33.3%) cases of serous carcinomas. Twenty three (76.6%) cases of control group demonstrated nuclear expression. High score cyclin D1 immunohistochemical staining has been significantly linked with patient age (P=0.0001). Large proportion of high score cyclin D1 immunohistochemical staining was observed in females who are <40years of age while high proportions of negative staining were observed in older age groups. Histologic type of tissue was also significantly related to cyclin D1 immunohistochemical staining (P-value=0.0001), high staining is more common in normal proliferative and secretory endometrium while serous carcinoma is more prevalent with negative staining. Stage of tumor was significantly associated with cyclin D1 immunohistochemical staining (P-value=0.029), proportion of stage III and IV are higher in negative cyclin D1 immunostaining. Significantly higher proportion of high score cyclin D1 immunostaining is observed in controls while higher proportion of negative cyclin D1 immunostaining is observed among carcinoma cases (P-value=0.0001). No significant associations between cyclin D1 immunohistochemical staining and grade, recurrence and alive status were observed. Significant different survival distributions were observed (P-value=0.011) and poor survival behavior was correlated with negative cyclin D1 immunohistochemical staining. In conclusion, greater frequency of cyclin D1 expression was revealed in normal endometrial tissues in comparison with carcinomas. The distribution pattern of cyclin D1 immunoexpression suggests poor prognoses in endometrial carcinoma patients.

Clusterin immunoexpression is associated with early stage endometrial carcinomas

Clusterin has anti-apoptotic, regeneration and migration stimulating effects on tumor cells. This study investigates the relation between clusterin expression and the clinicopathological parameters in endometrial carcinomas. Seventy one cases of previously diagnosed endometrial carcinoma (including 59 endometrioid adenocarcinoma, 9 serous adenocarcinoma, 1 clear cell adenocarcinoma, and 2 malignant mixed Mullerian tumor) and 30 tissue samples of non-cancerous endometrium (including 16 proliferative endometrium, 10 secretory endometrium and 4 endometrial polyps) were employed for clusterin detection using tissue microarrays and immunostaining. A total number of 23 (32.4%) cases were positive for clusterin immunostaining. Brown granular cytoplasmic expression of clusterin was detected in 33.9% of endometrioid adenocarcinomas, 22.2% papillary serous endometrial carcinomas. Three (10%) control cases showed granular cytoplasmic expression. Positive clusterin immunostaining was found more frequent in well differentiated and stage I endometrial carcinomas, showing significant statistical association (p-value=0.036 and p-value=0.002 respectively). Significant difference in clusterin expression was observed between tumor cases and control group (P-Value=0.019), i.e., endometrial carcinoma cases are more than four times likely to show positive clusterin immunostaining (odds ratio 4.313 with 95% confidence interval 1.184-15.701). This study did not find relation between clusterin expression and disease recurrence, survival or any of the other clinicopathological parameters in endometrial tumors. The results of our study confirms the diagnostic values of clusterin in supporting the diagnosis of endometrioid carcinoma. When clusterin is expressed in endometrial tumors, it is associated with lower stage. The correlation of clusterin with tumor stage suggests involvement of this molecule in endometrial tumor progression.

Psychometric Analysis of Depression, Anxiety and Stress Among Women of Wazirabad City

In this paper psychometric analysis of Depression, Anxiety and Stress among Women living in Wazirabad City has been explored. Cluster sampling technique was used to collect a sample of size 334. For this purpose Urdu version of Depression, Anxiety and Stress (DASS-21) questionnaire was administered along with 10 demographic. DASS-21 data has been analyzed to study the relationship between “depression”, “anxiety” and “stress” across various demographic characteristics. DASS-21 shown good internal consistency (Cronbach’s alpha 0.86) and Confirmatory Factor Analysis showed consistency with previously found factor structures. Strong relationship of “anxiety” and “stress” has been observed with age; while no association was observed with “income”. “Education” has mild effect with the items of “depression”, “anxiety” and “stress”. “Illness” and “occupation” found to be strong factors of “depression”, “anxiety” and “stress”. Another major factor of “stress” found to be “family living system” while “marital status” also affects some of items.

ANOVA with Summary Statistics: A Stata Macro

Almost all available statistical packages are capable of performing Analysis of Variance (ANOVA) from raw data. Some of statistical packages have capability to perform independent sample t-test, and some other tests of significance on summary data, but seldom would you come across a software that has the capability to perform ANOVA directly on summary data. However some packages can perform one-way ANOVA after generating surrogate data from summary statistics. In this short note we have given STATA program to perform one-way ANOVA on summary data; in addition this program also performs Bartllet’s tests of equality of variances. The idea can be extended to two-way and higher way ANOVA’s. Examples have been given for illustration.

Awareness of diabetic retinopathy among people with diabetes in Jeddah, Saudi Arabia

Background: Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus (DM) and the foremost cause of blindness. This study aimed to assess the level of awareness of DR and its related risk factors among patients with DM in Jeddah, Saudi Arabia. Methods: A cross-sectional study was conducted among patients with DM attending primary health care centers at the Ministry of Health in Jeddah. A structured, pretested, self-administered questionnaire was used to collect information on the sociodemographic and DM- and DR-related characteristics of the patients. Results: A total of 377 patients were enrolled. About 82.6% of the patients were aware that DM can affect their eyes, and they listed physicians, ophthalmologists, television, and family members as common sources of information on the topic. About 36% of the patients reported that their doctors had not advised them about it. More than half responded that they did not feel their vision to be affected by DM. More than 58% had never been diagnosed with DR. About 35% did not go to their eye checkups, even though around 59% thought that DR could lead to blindness. Of the 64% of patients whose DM was well controlled, 11% and 25% listed surgery and laser treatment, respectively, as available treatment options for DR. The following factors were found to be significant in relation to the subjects’ awareness that DM can affect their eyes: the patients’ perception of their doctors’ advice about DR; the experience of having their vision affected by DM; the knowledge that DR may lead to blindness; the practice of going to eye checkups. Conclusions: Despite having good awareness about DM and its effects on eyes, the patients exhibited a relative lack of awareness about DR. Considering the association of DR with DM, its increasing magnitude is a potential burden on the community and health systems.

Immunohistochemical expression of galectin-3 is significantly associated with grade, stage and differentiation of endometrial carcinomas

This study describes galectin-3 immunohistochemical phenotype and its association with clinicopathological factors in the carcinoma of endometrium. Seventy one cases of endometrial carcinoma and 30 cases of benign and normal endometrium were employed for the detection of galectin-3 protein using tissue microarrays and immunohistochemistry staining. Thirty nine (55%) cases, including 54.2% of endometrioid adenocarcinomas and 55.5% serous carcinomas, were positively stained for galectin-3. Brown granular expression of this glycoprotein was detected in transformed epithelial cells of 36 cases including 28 cases with membranous and cytoplasmic staining and 8 cases with only cytoplasmic staining; nuclear expression was present in stromal cells of the remaining 3 cases. Twenty-four (80%) control cases showed granular cytoplasmic and membranous expression, and six control cases were negative. Tumor grade, stage and differentiation were significantly associated with galectin-3 immunoreactivity (p-values are 0.043, 0.016, and 0.044 respectively), cases with membranous and cytoplasmic staining is significantly associated with grade I and stage II, while cases with loss of staining are more frequent in grade II, III and poorly differentiated tumors. No significant association of galectin-3 staining was observed with age, diagnosis, recurrence and alive status. The current study supports the tumor suppression role of galectin-3 in endometrial carcinoma. Greater galectin-3 immunostaining has been found in control endometrial tissues compared to endometrial tumors. Loss or decreased galectin-3 immunoexpression gives a sign for poor prognoses in endometrial carcinoma patients.