49 research outputs found
Molecular and morphological characterization of the tapeworm Taenia hydatigena (Pallas, 1766) in sheep from Iran
Although Taenia hydatigena is one of the most prevalent taeniid species of livestock, very little molecular genetic information exists for this parasite. Up to 100 sheep isolates of T. hydatigena were collected from 19 abattoirs located in the provinces of Tehran, Alborz and Kerman. A calibrated microscope was used to measure the larval rostellar hook lengths. Following DNA extraction, fragments of cytochrome c oxidase 1 (CO1) and 12S rRNA genes were amplified by the polymerase chain reaction method and the amplicons were subjected to sequencing. The mean total length of large and small hooks was 203.4 μm and 135.9 μm, respectively. Forty CO1 and 39 12S rRNA sequence haplotypes were obtained in the study. The levels of pairwise nucleotide variation between individual haplotypes of CO1 and 12S rRNA genes were determined to be between 0.3-3.4% and 0.2-2.1%, respectively. The overall nucleotide variation among all the CO1 haplotypes was 9.7%, and for all the 12S rRNA haplotypes it was 10.1%. A significant difference was observed between rostellar hook morphometry and both CO1 and 12S rRNA sequence variability. A significantly high level of genetic variation was observed in the present study. The results showed that the 12S rRNA gene is more variable than CO1. © 2013 Cambridge University Press
Seroprevalence and risk factors of Toxoplasma gondii infection among healthy blood donors in south‐east of Iran
This prospective cross-sectional study was aimed to evaluate
the prevalence of IgM and IgG anti-T. gondii antibodies
and the associated risk factors among healthy blood donors
in Kerman province, south-eastern Iran. Structured questionnaires
(before the donors gave blood) were used to obtain
information on risk factors for infection. Totally, 500 serum
samples from healthy blood donors of Kerman Blood Transfusion
Organization (KBTO) at Kerman, Iran, were
screened for IgG and IgM anti-T. gondii antibodies by
enzyme-linked immunosorbent assay (ELISA) and Roche
Elecsys Toxo IgM assay. Real-time PCR was used to detect
DNA of T. gondii in the IgM-positive samples. Seroprevalence
of IgG and IgM anti-T. gondii antibodies was 28�8%
and 3�2%, respectively. In the multiple logistic regression, it
could be observed that living in rural regions, having B blood
type, being in contact with cats, consuming raw vegetables
and raw milk/egg and doing agricultural activities were independent
risk factors for Toxoplasma seropositivity. T. gondii
DNA was also found in one (9�0%) of IgM-positive
samples. In this study, it was found that T. gondii infection
was present among healthy blood donors in south-east of
Iran. Therefore, it is suggested to design screening
programmes for preventing transfusion-transmitted
toxoplasmosi
Molecular and morphological characterization of the tapeworm Taenia hydatigena (Pallas, 1766) in sheep from Iran
Although Taenia hydatigena is one of the most prevalent taeniid species of
livestock, very little molecular genetic information exists for this parasite. Up to
100 sheep isolates of T. hydatigena were collected from 19 abattoirs located in the
provinces of Tehran, Alborz and Kerman. A calibrated microscope was used to
measure the larval rostellar hook lengths. Following DNA extraction, fragments
of cytochrome c oxidase 1 (CO1) and 12S rRNA genes were amplified by the
polymerase chain reaction method and the amplicons were subjected to
sequencing. The mean total length of large and small hooks was 203.4 mm and
135.9 mm, respectively. Forty CO1 and 39 12S rRNA sequence haplotypes were
obtained in the study. The levels of pairwise nucleotide variation between
individual haplotypes of CO1 and 12S rRNA genes were determined to be
between 0.3–3.4% and 0.2–2.1%, respectively. The overall nucleotide variation
among all the CO1 haplotypes was 9.7%, and for all the 12S rRNA haplotypes it
was 10.1%. A significant difference was observed between rostellar hook
morphometry and both CO1 and 12S rRNA sequence variability. A significantly
high level of genetic variation was observed in the present study. The results
showed that the 12S rRNA gene is more variable than CO1
Bayesian mixture cure rate frailty models with an application to gastric cancer data
Mixture cure rate models are commonly used to analyze lifetime data with long-term survivors. On the other hand, frailty models also lead to accurate estimation of coefficients by controlling the heterogeneity in survival data. Gamma frailty models are the most common models of frailty. Usually, the gamma distribution is used in the frailty random variable models. However, for survival data which are suitable for populations with a cure rate, it may be better to use a discrete distribution for the frailty random variable than a continuous distribution. Therefore, we proposed two models in this study. In the first model, continuous gamma as the distribution is used, and in the second model, discrete hyper-Poisson distribution is applied for the frailty random variable. Also, Bayesian inference with Weibull distribution and generalized modified Weibull distribution as the baseline distribution were used in the two proposed models, respectively. In this study, we used data of patients with gastric cancer to show the application of these models in real data analysis. The parameters and regression coefficients were estimated using the Metropolis with Gibbs sampling algorithm, so that this algorithm is one of the crucial techniques in Markov chain Monte Carlo simulation. A simulation study was also used to evaluate the performance of the Bayesian estimates to confirm the proposed models. Based on the results of the Bayesian inference, it was found that the model with generalized modified Weibull and hyper-Poisson distributions is a suitable model in practical study and also this model fits better than the model with Weibull and Gamma distributions. © The Author(s) 2020
Factors Affecting Long-Survival of Patients with Breast Cancer by Non-Mixture and Mixture Cure Models Using the Weibull, Log-logistic and Dagum Distributions: A Bayesian Approach
Background: Breast cancer is a top biomedical research priority, and it is a major health problem. Therefore, the present study aimed to determine the prognostic factors of breast cancer survival using cure models. Methods: In this retrospective cohort analytic study, data of 140 breast cancer patients were collected from Ali Ibn Abi Taleb hospital, Rafsanjan, Southeastern Iran. Since in this study, a part of the population had long-term survival, cure models were used and evaluated using DIC index. The data were analyzed using Openbugs Software. Results: In this study, of 140 breast cancer patients, 23 (16.4) cases died of breast cancer. Based on the findings, the Bayesian nonmixture cure model, with type I Dagum distribution, was the best fitted model. The variables of BMI, number of children, number of natural deliveries, tumor size, metastasis, consumption of canned food, tobacco use, and breastfeeding affected patients� survival based on type I Dagum distribution. Conclusion: The results of the present study demonstrated that the Bayesian nonmixture cure model, with type I Dagum distribution, can be a good model to determine factors affecting the survival of patients when there is the possibility of a fraction of cure. In this study, it was found that adapting a healthy lifestyle (eg, avoiding canned foods and smoking) can improve the survival of breast cancer patients. © This work is licensed under a Creative Commons Attribution Non Commercial 4.0 International License
Augmentation of the think aloud method with users� perspectives for the selection of a picture archiving and communication system
Objectives: Users attitude toward a picture archiving and communication system (PACS) and their interaction with this system are among the most important factors that influence its acceptance. This study aimed to augment the user's interaction with the user's perspective to select a usable PACS among three systems available on the market. Methods: We augmented the think aloud (TA) usability evaluation method with the Post-Study System Usability Questionnaire (PSSUQ) to compare user interaction problems of three PACS user interfaces. Four radiologists and four internist physicians participated in this study. Usability characteristics including efficiency, effectiveness, learnability, error, and satisfaction were used to assess the usability of each PACS. Results: There was a significant difference in efficiency (p = 0.01), effectiveness (p = 0.005), learnability (p = 0.001), and satisfaction (p = 0.009). However, no significant difference in the number of errors (p = 0.18), mouse clicks and keystrokes (p = 0.12), and the number of usability problems (p = 0.6) were observed among the three PACS systems studied. Conclusions: This study showed that applying the proposed approach to augment TA with the user's perspective addresses almost all of the theoretical aspects of usability and can be employed to select the most usable PACS. © 201