A system dynamics model for national drug policy

Background

Data modeling techniques can create a virtual world to analyze decision systems. National drug authorities can use such techniques to take care of their deficiencies in decision making processes. This study was designed to build a system dynamics model to simulate the effects of market mix variables (5 P’s) on the national drug policy (NDP) indicators including availability, affordability, quality, and rationality. This was aimed to investigate how to increase the rationality of decision making, evaluate different alternatives, reduce the costs and identify the system obstacles.System dynamics is a computer-based approach for analyzing and designing complex systems over time. In this study the cognitive casualty map was developed to make a concept about the system then the stock-flow model was set up based on the market demand and supply concept.

Results

The model demonstrates the interdependencies between the NDP variables through four cognitive maps. Some issues in availability, willingness to pay, rational use and quality of medicines are pointed in the model. The stock-flow diagram shows how the demand for a medicine is formed and how it is responded through NDP objectives. The effects of changing variables on the other NDP variables can be studied after running the stock-flow model.

Conclusion

The model can initiate a fundamental structure for analyzing NDP. The conceptual model made a cognitive map to show many causes’ and effects’ trees and reveals some relations between NDP variables that are usually forgotten in the medicines affairs. The model also provides an opportunity to be expanded with more details on a specific disease for better policy making about medication.     

In Vitro Comparison of Two Different Mechanical Circulatory Support Devices Installed in Series and in Parallel

This study investigates the novel approach of placing a ventricular assist pump in the descending aorta in series configuration with the heart and compares it with the two traditional approaches of left‐ventricle‐to‐ascending‐aorta (LV‐AA) and left‐ventricle‐to‐descending‐aorta (LV‐DA) placement in parallel with the heart. Experiments were conducted by using the in‐house simulator of the cardiovascular blood‐flow loop (SCVL). The results indicate that the use of the LV‐AA in‐parallel configuration leads to a significant improvement in the systemic and pulmonic flow as the level of continuous flow is increased; however, this approach is considered highly invasive. The use of the LV‐DA in‐parallel configuration leads to an improvement in the systemic and pulmonic flow at lower levels of continuous flow but at higher levels of pump support leads to retrograde flow. In both in‐parallel configurations, increasing the level of pump continuous flow leads to a decrease in pulsatility to a certain extent. The results of placing the pump in the descending aorta in series configuration show that the pressure drop upstream of the pump facilitates cardiac output as a result of afterload reduction. In addition, the pressure rise downstream of the pump may assist with renal perfusion. However, at the same time, the pressure drop generated at the proximal part of the descending aorta induces a slight drop in carotid perfusion, which would be autoregulated by the brain in a native cardiovascular system. The pulse wave analysis shows that placing the pump in the descending aorta leads to improved pulsatility in comparison with the traditional in‐parallel configurations.     

Agreement between DSM-IV and ICD-10 criteria for opioid use disorders in two Iranian samples

The aim of this study was to determine the agreement between the two systems in opioid users in the general population and a clinical sample. Two series of data were used in this study. The first was the data of 236 home-residing opioid abusers aged 15–64, who had previously participated in the Iran Mental Health Survey (IranMHS) in 2011, and the second was the data of 104 general psychiatry patients from inpatient or outpatient wards of two psychiatry hospitals in Tehran. Opioid use disorders were evaluated with CIDI-version 2.1. The disorders were assessed in all participants who used opioid substances for at least 5 times during the past 12 months. In the sample from the general population, the agreement between the two systems on the diagnosis of dependence was excellent (0.81). The agreement between the two systems on the diagnosis of abuse and harmful use was 0.41. In the clinical sample, the agreement between the two systems on the diagnosis of dependence or any opioid use disorder was 0.96 and 0.93, respectively. The agreement between abuse and harmful use was 0.9 and − 0.02 with and without regarding hierarchy, respectively. The inter-rater reliability of both DSM-IV and ICD-10 systems for all diagnosis was more than 0.95. The results of the diagnosis of dependence in the two systems had a weak concordance with treatment. The diagnostic criteria of DSM-IV and ICD-10 regarding dependence are very similar and the diagnosis produced by each system is concordant with the other system. However, the two systems have noticeable discrepancies in the diagnosis of abuse and harmful use. The discrepancies result from their conceptual differences and necessitate further revision in the definition of these disorders in the two systems.     

Standardization of Prothrombin Time/International Normalized Ratio (PT/INR)

The prothrombin time (PT) represents the most commonly used coagulation test in clinical laboratories. The PT is mathematically converted to the international normalized ratio (INR) for use in monitoring anticoagulant therapy with vitamin K antagonists such as warfarin in order to provide test results that are adjusted for thromboplastin and instrument used. The INR is created using two major PT ‘correction factors’, namely the mean normal PT (MNPT) and the international sensitivity index (ISI). Manufacturers of reagents and coagulometers have made some efforts to harmonizing INRs, for example, by tailoring reagents to specific coagulometers and provide associated ISI values. Thus, two types of ISIs may be generated, with one being a ‘general’ or ‘generic’ ISI and others being reagent/coagulometer-specific ISI values. Although these play a crucial role in improving INR results between laboratories, these laboratories reported INR values are known to still differ, even when laboratories use the same thromboplastin reagent and coagulometer. Moreover, ISI values for a specific thromboplastin can vary among different models of coagulometers from a manufacturer using the same method for clot identification. All these factors can be sources of error for INR reporting, which in turn can significantly affect patient management. In this narrative review, we provide some guidance to appropriate ISI verification/validation, which may help decrease the variability in cross laboratory reporting of INRs.     

Prevalence of drug resistance under the DOTS strategy in Hyderabad, South India, 2001-2003.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB), defined as resistance to at least isoniazid (INH) and rifampicin (RMP), is considered a threat to TB control. Implementation of DOTS ensures high cure rates and prevents MDR. OBJECTIVE: To study the prevalence of MDR-TB from a retrospective analysis of the data in a tuberculosis unit where DOTS was implemented over a period of 6 years through public private mix (PPM). METHODS: Drug susceptibility testing of Mycobacterium tuberculosis samples isolated from the cultures of newly registered and retreatment sputum smear-positive cases during 2001-2003. RESULTS: During the study, 909 sputum-positive cases were registered and analysed. Of these, 714 were new and 195 were retreatment sputum-positive cases. INH resistance was found in 3.2% (23) of new and 9.2% (18) of retreatment cases. RMP resistance was present in 1.5% (11) of new and 7.2% (14) of retreatment cases. MDR was present only in 0.14% (1) of new and 2% (4) of retreatment cases. New cases had cure rates of 96% compared to 85% in retreatment cases. CONCLUSION: The prevalence of MDR-TB is low where success rates are high.     

Plurihormonal pituitary adenoma with concomitant adrenocorticotropic hormone (ACTH) and growth hormone (GH) secretion: a report of two cases and review of the literature

Plurihormonal pituitary adenomas are tumours that show immunoreactivity for more than one hormone that cannot be explained by normal adenohypophysial cytodifferentiation. The most common combinations in these adenomas include growth hormone (GH), prolactin (PRL) and one or more glycoprotein hormone sub-units (β-TSH, β-FSH, β-LH and αSU). The authors report two cases of a plurihormonal pituitary adenoma expressing the rare combination of ACTH and GH. They both underwent successful transphenoidal hypophysectomy (TSH). Long-term post-operative follow-up revealed no evidence of tumour recurrence. Due to the multiple secretions and plurihormonal characteristics clinical diagnosis of composite pituitary adenomas can be difficult. The authors discuss the diagnosis and management of composite pituitary adenomas and review the literature regarding this rare phenomenon.     

Natural products against cancer: Review on phytochemicals from marine sources in preventing cancer

Marine natural products have as of now been acknowledged as the most important source of bioactive substances and drug leads. Marine flora and fauna, such as algae, bacteria, sponges, fungi, seaweeds, corals, diatoms, ascidian etc. are important resources from oceans, accounting for more than 90% of the total oceanic biomass. They are taxonomically different with huge productive and are pharmacologically active novel chemical signatures and bid a tremendous opportunity for discovery of new anti-cancer molecules. The water bodies a rich source of potent molecules which improve existence suitability and serve as chemical shield against microbes and little or huge creatures. These molecules have exhibited a range of biological properties antioxidant, antibacterial, antitumour etc. In spite of huge resources enriched with exciting chemicals, the marine floras and faunas are largely unexplored for their anticancer properties. In recent past, numerous marine anticancer compounds have been isolated, characterized, identified and are under trials for human use. In this write up we have tried to compile about marine-derived compounds anticancer biological activities of diverse flora and fauna and their underlying mechanisms and the generous raise in these compounds examined for malignant growth treatment in the course of the most recent quite a long while.     

The Effect and Side Effect of Hydroxyurea Therapy on Patients With β-Thalassemia: A Systematic Review to December 2012

Hydroxyurea (HU) is being used for patients with transfusion-dependent β-thalassemia major (β-TM) as well as non transfusion-dependent β-TM. As controversy exists regarding efficacy and safety of HU, we searched the published literature on efficacy, effectiveness and toxicity of HU in patients with β-TM. The research sources we used were: Medline, SID, PubMed, Scopus, Request, Web of Knowledge, Springer, Ovid, Cochrane searched up to October 2012. Using search terms sensitive to studies of clinical trials combined with searches on terms related to thalassemia and HU. We selected studies on randomized trials, quasi experimental trials (before and after design), case reports (with 1–5 cases), side effect studies in patients with β-TM, studies related to the mechanism of action and toxicity when used in patients with other hemoglobinopathies. We researched studies in English and Persian. Eligible articles were reviewed by two independent reviewers. Patient’s characteristics, duration of trial, outcome and side effects were extracted. The main outcomes were synthesized under a random-effects model. Heterogeneity was assessed using the Q statistic, Tau² and I². Subgroup analyses were performed and the statistics data (STATA) software used. More than 500 articles were reviewed. No randomized clinical trial was found. Seventeen trials with before and after designs were found, 16 case reports (1–5 cases), 19 articles for mechanism of action and 16 studies for side effects were published from 1969 to October 2012. Hemoglobin levels after treatment showed modest but significant increase in non transfusion-dependent β-TM (p?p?相似文献