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Search Results: 1 - 10 of 455 matches for " Payam Nahid "
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Impact of Isoniazid Resistance-Conferring Mutations on the Clinical Presentation of Isoniazid Monoresistant Tuberculosis
Raymund Dantes, John Metcalfe, Elizabeth Kim, Midori Kato-Maeda, Philip C. Hopewell, Masae Kawamura, Payam Nahid, Adithya Cattamanchi
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037956
Abstract: Background Specific isoniazid (INH) resistance conferring mutations have been shown to impact the likelihood of tuberculosis (TB) transmission. However, their role in the clinical presentation and outcomes of TB has not been evaluated. Methods We included all cases of culture-confirmed, INH monoresistant tuberculosis reported to the San Francisco Department of Public Health Tuberculosis Control Section from October 1992 through October 2005. For cases with stored culture isolates, we used polymerase chain reaction (PCR) testing and gene sequencing to identify INH resistance-conferring mutations, and compared genotypic and phenotypic characteristics. Results Among 101 consecutive cases of INH monoresistant TB in San Francisco 19 (19%) had isolates with a katG mutation other than S315T; 38 (38%) had isolates with the katG S315T mutation, 29 (29%) had isolates with a inhA-15;c-t promoter mutation, and 15 (15%) had isolates with other mutations. The katG S315T mutation was independently associated with high-level INH resistance (risk ratio [RR] 1.56, 95% confidence interval [CI] 1.07–2.27), and the inhA-15;c-t promoter mutation was inversely associated with high-level INH resistance (RR 0.43, 95% CI 0.21–0.89). However, specific INH resistance-conferring mutations were not associated with the clinical severity or outcomes of INH monoresistant TB cases. Conclusion These data suggest that INH resistance-conferring mutations do not impact the clinical presentation of TB.
Pyrazinamide Resistance, Mycobacterium tuberculosis Lineage and Treatment Outcomes in San Francisco, California
Jonathan M. Budzik, Leah G. Jarlsberg, Julie Higashi, Jennifer Grinsdale, Phil C. Hopewell, Midori Kato-Maeda, Payam Nahid
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095645
Abstract: Background Pyrazinamide (PZA) is a first line agent for the treatment of active tuberculosis. PZA is also considered a potent companion drug for newer regimens under development. There are limited data on the demographic, clinical, and pathogen characteristics of PZA resistant tuberculosis. Methods Using a retrospective cohort study design, we evaluated all PZA resistant M. tuberculosis (M.tb) and M. bovis cases reported in San Francisco from 1991 to 2011. Demographic, clinical, and molecular data were analyzed. M.tb lineage was determined for all PZA resistant strains and compared to PZA susceptible strains. Results PZA resistance was identified in 1.8% (50 of 2,842) of mycobacterial isolates tested, corresponding to a case rate of 0.3 per 100,000 in the population. Monoresistant PZA infection was associated with the Hispanic population ([OR], 6.3; 95% [CI], 1.97–20.16) and 48% of cases were due to M. bovis. Infection with monoresistant PZA was also associated with extrapulmonary disease ([OR], 6.0; 95% [CI], 2.70–13.26). There was no statistically significant difference between treatment failure and mortality rates in patients infected with PZA monoresistance compared to pansusceptible controls (4% vs. 8%, p = 0.51), or those with PZA and MDR resistance (PZA-MDR) compared to MDR controls (18% vs. 29%, p = 0.40). PZA resistance was not associated with M.tb lineage. Conclusions Across two decades of comprehensive epidemiologic data on tuberculosis in San Francisco County, PZA resistance was uncommon. PZA resistance caused predominantly extrapulmonary disease and was more common in Hispanics compared to other ethnicities, with nearly half the cases attributed to M. bovis. No association was found between PZA monoresistance and M.tb lineage. Treatment outcomes were not adversely influenced by the presence of PZA resistance.
Throughput Maximizing Frequency and Power Scheduling for Wireless Ad-Hoc Networks in the Low-SINR Regime  [PDF]
Nahid Saberi
Wireless Engineering and Technology (WET) , 2012, DOI: 10.4236/wet.2012.33017
Abstract: We study the problem of frequency and power allocation and scheduling at a time-slotted cognitive ad-hoc wireless network, where cognitive nodes share a number of frequency bands and frequency reuse is allowed. In such a network the throughput maximization problem generally results in a mixed zero-one nonlinear non-convex problem. Interestingly, in the low-SINR regime, the power allocation policy that maximizes the total throughput follows an “on/off” strategy with maximum power usage in the “on” state. In this paper we show that the on/off strategy in the low-SINR regime is also optimal with respect to throughput when scheduling users over time and frequency subject to minimum SINR requirements. We show that these additional constraints will not change the optimum strategy, but may affect the set of “on” or “off” transmitters. Also we present an approach that transforms the mixed zero-one nonlinear problem to an equivalent mixed zero-one linear problem at the expense of extra variables.
Factors associated with mortality in patients with drug-susceptible pulmonary tuberculosis
Payam Nahid, Leah G Jarlsberg, Irina Rudoy, Bouke C de Jong, Alon Unger, L Masae Kawamura, Dennis H Osmond, Philip C Hopewell, Charles L Daley
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-1
Abstract: Retrospective chart review of patients with drug-susceptible tuberculosis reported to the San Francisco Tuberculosis Control Program from 1990-2001.Of 565 patients meeting eligibility criteria, 37 (6.6%) died during the study period. Of 37 deaths, 12 (32.4%) had tuberculosis listed as a contributing factor. In multivariate analysis controlling for follow-up time, four characteristics were independently associated with mortality: HIV co-infection (HR = 2.57, p = 0.02), older age at tuberculosis diagnosis (HR = 1.52 per 10 years, p = 0.001); initial sputum smear positive for acid fast bacilli (HR = 3.07, p = 0.004); and experiencing an interruption in tuberculosis therapy (HR = 3.15, p = 0.002). The association between treatment interruption and risk of death was due to non-adherence during the intensive phase of treatment (HR = 3.20, p = 0.001). The median duration of treatment interruption did not differ significantly in either intensive or continuation phases between those who died and survived (23 versus 18 days, and 37 versus 29 days, respectively). No deaths were directly attributed to adverse drug reactions.In addition to advanced age, HIV and characteristics of advanced tuberculosis, experiencing an interruption in anti-tuberculosis therapy, primarily due to non-adherence, was also independently associated with increased risk of death. Improving adherence early during treatment for tuberculosis may both improve tuberculosis outcomes as well as decrease mortality.Tuberculosis is a leading cause of death worldwide. According to the World Health Organization (WHO) over 1.7 million people with tuberculosis died in 2008 [1]. Advanced age, male gender, delays in diagnosis and treatment, drug resistance, and co-morbid conditions including HIV co-infection, diabetes, renal disease and COPD, have been associated with increased risk of death in patients with active tuberculosis [2-8]. A substantial proportion of deaths occur during tuberculosis treatment despite patient
Elucidating Novel Serum Biomarkers Associated with Pulmonary Tuberculosis Treatment
Mary A. De Groote, Payam Nahid, Leah Jarlsberg, John L. Johnson, Marc Weiner, Grace Muzanyi, Nebojsa Janjic, David G. Sterling, Urs A. Ochsner
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061002
Abstract: In an unbiased approach to biomarker discovery, we applied a highly multiplexed proteomic technology (SOMAscan, SomaLogic, Inc, Boulder, CO) to understand changes in proteins from paired serum samples at enrollment and after 8 weeks of TB treatment from 39 patients with pulmonary TB from Kampala, Uganda enrolled in the Center for Disease Control and Prevention’s Tuberculosis Trials Consortium (TBTC) Study 29. This work represents the first large-scale proteomic analysis employing modified DNA aptamers in a study of active tuberculosis (TB). We identified multiple proteins that exhibit significant expression differences during the intensive phase of TB therapy. There was enrichment for proteins in conserved networks of biological processes and function including antimicrobial defense, tissue healing and remodeling, acute phase response, pattern recognition, protease/anti-proteases, complement and coagulation cascade, apoptosis, immunity and inflammation pathways. Members of cytokine pathways such as interferon-gamma, while present, were not as highly represented as might have been predicted. The top proteins that changed between baseline and 8 weeks of therapy were TSP4, TIMP-2, SEPR, MRC-2, Antithrombin III, SAA, CRP, NPS-PLA2, LEAP-1, and LBP. The novel proteins elucidated in this work may provide new insights for understanding TB disease, its treatment and subsequent healing processes that occur in response to effective therapy.
Childhood Tuberculosis in Northern Viet Nam: A Review of 103 Cases
Robert J. Blount, Bao Tran, Leah G. Jarlsberg, Ha Phan, Van Thanh Hoang, Nhung Viet Nguyen, Deborah A. Lewinsohn, Payam Nahid
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0097267
Abstract: Background Childhood tuberculosis causes significant morbidity and mortality in Southeast Asia, yet little is known about the epidemiology and clinical characteristics of this disease in Viet Nam. Objectives To determine the demographics, clinical presentations, radiographic and microbiologic findings, treatment regimens, and outcomes of children admitted with tuberculosis (TB) to a national referral hospital in Viet Nam. Methods We conducted a retrospective case series study of children ≤ 15 years old with bacteriologically confirmed or clinically diagnosed TB admitted to a national referral hospital in Ha Noi, Viet Nam from January through December 2007. Results One hundred three children were identified: median age 5 years (IQR 2-10), 44% female, 99% Kinh ethnicity, 27% residing in Ha Noi, 88% with BCG vaccination, 27% with known TB contact, and 38% malnourished. Intrathoracic TB was present in 62%, extrathoracic in 52%, both intra and extrathoracic in 19%, and undetermined site in 5%. The most common extrathoracic manifestation was peripheral lymphadenitis, and children under 5 were more likely to have miliary TB or both intra and extrathoracic TB. Fever and failure to thrive were common presenting symptoms among all participants (65% and 56%, respectively), 66% of those with intrathoracic TB presented with cough, and 92% of those with TB meningitis presented with severe neurologic impairment. Acid-fast bacilli smears and mycobacterial cultures were positive in 18% and 21% of children tested, and histopathology was positive in 88% of those biopsied. There were no adverse drug reactions necessitating change in therapy, and no inpatient mortality. Conclusions Extrathoracic TB was common, treatment well tolerated and clinical outcomes excellent. Culture confirmation rates were low and emphasize the need for improved diagnostics.
An Inquiry into Cultural Continuity and Change in Housing: An Iranian Perspective  [PDF]
Rafooneh Mokhtarshahi Sani, Payam Mahasti
Sociology Mind (SM) , 2013, DOI: 10.4236/sm.2013.33031
Abstract:

The arrival of modernization has had an adverse effect on current Iranian housing architecture; as such, that it is now finds itself in a difficult predicament. Therefore, various national architectural conferences, in addition to individual investigations, have been focused on the renewal of Iranian housing architecture over recent decades. Whilst these examples have not culminated or resulted in defining a clear Iranian trend and style in housing with recognizable characteristics, it would be useful to explore some of the more successful examples in order to obtain an overview of what has been done in Iran in this respect during recent years. Accordingly, the study has focused on identifying the architectural characteristics of Iranian houses, which have been modified and used in the present designs. In this study, through a comparative typological analysis of the different traditional Iranian housing types, their main characteristics have been categorized. The categorization later applied for the analysis of the contemporary houses designs. The results of this investigation have shown that, in contemporary samples, although the idea of Iranian traditional houses has remained; the concept of traditional houses has been altered and changed.

The Relationship between Locus of Control, Test Anxiety, and Religious Orientation among Iranian EFL Students  [PDF]
Mina Rastegar, Nahid Heidari
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.31009
Abstract:

The present study was designed to investigate the relationship between locus of control (LOC), religious orientation (RO) and test anxiety (TA) among Iranian EFL learners. Furthermore, it scrutinized the role of gender on these variables. To achieve such goals, 100 Iranian EFL students (57 females, 43 males) studying English at Shahid Bahonar University of Kerman participated in the study. These students were randomly selected from among junior and senior students majoring in English Translation and English Literature. In order to obtain the required data, three questionnaires were utilized: Rotters’s (1966) locus of control scale (LOCS) to measure participants’ level of LOC, Sarason’s (1975) test anxiety scale (TAS) to measure participants’ TA, and Allport and Ross’s (1967) Religious Orientation Scale (ROS) to determine participants’ intrinsic or extrinsic religious orientation. For analysis of data, the Pearson Product Moment Correlation and T-test were used. The results revealed that there was a significant negative relationship between ILOC and TA and a significant positive relationship between ELOC and TA. Furthermore, there was a significant positive relationship between ILOC and IRO and a significant positive relationship between ELOC and ERO. Also, there was a significant negative relationship between ILOC and TA, and a significant positive relationship between ELOC and TA. Finally, there were not any significant differences among males and females regarding ILOC, ELOC, TA, IRO, and ERO.

Assessment of CropWat Model Accuracy for Estimating Potential Evapotranspiration in Arid and Semi-arid Region of Iran
Payam Najafi
Pakistan Journal of Biological Sciences , 2007,
Abstract: The aim of this research was estimating the accuracy of CropWat software to calculating potential evapotranspiration (ET0) in arid and semi-arid region of Iran. For this purpose, 9 locations of arid and semi-arid regions of Iran selected and the grass lysimeter data collected too. The lysimeter data are collected duration of May through November during 1988-1997. For the comparisons of the ET0 lysimeter data and ET0 resulted CropWat software in different point, three statistical parameters were used include Mean Absolute Relative Error (MARE), Root Mean Square Difference (RMSD) and correlation coefficient (R2). The results of this research show that the average of MARE, RMSD and R2 computed about 31%, 2.3 and 0.7, respectively in the study areas. In addition, the results of this research show that when the average of wind speed was less than 1 m sec-1 or wind speed was more than 1 m sec-1 with low ET0 lysimeter (ET0 less than 6 mm per day), CropWat has a low sensitive for estimating ET0 and it's necessary to improve the results for these areas. In concluded, the results of this research were showed that in these area because of intensive temperature and solar radiation, CropWat can not be estimated ET0 exactly.
The Realm of Management in Radiology: What Are the Borders?
Payam Tarighi
Iranian Journal of Radiology , 2010,
Abstract: If we carefully think about "management", there is little space in our life far from its influence. We feel the presence of management in every decision, from the most personalized matters to world-wide issues. In an interesting general model, there are four categories for management levels: managing yourself, managing people, managing the organization and finally, managing the society. So we need management as a scientific key for dealing with challenges in every category Challenges facing the medical imaging industry are numerous, such as handling daily changing technologies, managing resources (human and financial) for providing high competitive cost-effective consumer-satisfying services, quality improvement and many other obstacles. How can we be sure about the best practice, medical safety, correct investments, cost-saving and other similar topics in our settings? Questions like these can not be answered truly unless we believe management as an inseparable part of our practice which needs to be handled by professionals whether as consultants or as leaders. This presentation focuses on defining the realm of management in radiology from the health administration specialist point of view.
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