Improved diffusion imaging through SNR‐enhancing joint reconstruction

Quantitative diffusion imaging is a powerful technique for the characterization of complex tissue microarchitecture. However, long acquisition times and limited signal‐to‐noise ratio represent significant hurdles for many in vivo applications. This article presents a new approach to reduce noise while largely maintaining resolution in diffusion weighted images, using a statistical reconstruction method that takes advantage of the high level of structural correlation observed in typical datasets. Compared to existing denoising methods, the proposed method performs reconstruction directly from the measured complex k‐space data, allowing for Gaussian noise modeling and theoretical characterizations of the resolution and signal‐to‐noise ratio of the reconstructed images. In addition, the proposed method is compatible with many different models of the diffusion signal (e.g., diffusion tensor modeling and q‐space modeling). The joint reconstruction method can provide significant improvements in signal‐to‐noise ratio relative to conventional reconstruction techniques, with a relatively minor corresponding loss in image resolution. Results are shown in the context of diffusion spectrum imaging tractography and diffusion tensor imaging, illustrating the potential of this signal‐to‐noise ratio‐enhancing joint reconstruction approach for a range of different diffusion imaging experiments. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Adenosine induces cell cycle arrest and apoptosis via cyclinD1/Cdk4 and Bcl-2/Bax pathways in human ovarian cancer cell line OVCAR-3

Adenosine is a regulatory molecule with widespread physiological effects in almost every cells and acts as a potent regulator of cell growth. Adenosine has been shown to inhibit cell growth and induce apoptosis in the several cancer cells via caspase activation and Bcl-2/Bax pathway. The present study was designed to understand the mechanism underlying adenosine-induced apoptosis in the OVCAR-3 human ovarian cancer cells. MTT viability, BrdU and cell counting assays were used to study the cell proliferation effect of adenosine in presence of adenosine deaminase inhibitor and the nucleoside transporter inhibitor. Cell cycle analysis, propidium iodide and annexin V staining, caspase-3 activity assay, cyclinD1, Cdk4, Bcl-2 and Bax protein expressions were assessed to detect apoptosis. Adenosine significantly inhibited cell proliferation in a concentration-dependent manner in OVCAR-3 cell line. Adenosine induced cell cycle arrest in G0/G1 phase via Cdk4/cyclinD1-mediated pathway. Adenosine induced apoptosis, which was determined by Annexin V-FITC staining and increased sub-G1 population. Moreover, down-regulation of Bcl-2 protein expression, up-regulation of Bax protein expression and activation of caspase-3 were observed in response to adenosine treatment. The results of this study suggest that extracellular adenosine induced G1 cell cycle arrest and apoptosis in ovarian cancer cells via cyclinD1/ Cdk4 and Bcl-2/Bax pathways and caspase-3 activation. These data might suggest that adenosine could be used as an agent for the treatment of ovarian cancer.     

Molecular characterization of Staphylococcus aureus isolated from children with adenoid hypertrophy: emergence of new spa types t7685 and t7692

Objective

Adenoids have been associated with the pathogenesis of acute, recurrent and chronic infectious diseases of the upper respiratory system and their hypertrophy is one of the most common causes of upper airway obstruction affecting children. In this study, the characteristics of Staphylococcus aureus isolates from patients who had undergone adenoidectomy were investigated via spa typing method.

Methods

A total of 113 children with adenoid hypertrophy who underwent adenoidectomy during September 2009 to November 2010, were included in the study. The isolates were identified to the species level as S. aureus using standard biochemical methods, following which the amplification and sequencing of the spa gene X region were carried out.

Results

S. aureus was found in the adenoid tissue of 26 (23%) patients. Out of the 26 S. aureus isolates, 5 (19%), 3 (11.5%) and 3 (11.5%) were resistant to tetracycline, erythromycin and oxacillin respectively. All the isolates were susceptible to vancomycin, rifampin, ciprofloxacin, gentamicin, mupirocin and quinupristin-dalfopristin and were typed using spa typing method. All the isolates were found to include 21 spa types, including two previously unreported types (t7685 and t7692). The most prevalent spa types were t7685 (11.5%), t230 (8%), t325 (8%) and t1149 (8%).

Conclusion

This study demonstrates that the prevalence rate of S. aureus in the adenoid tissue of the children assessed was 23%. An interesting point to note was the dominance of the spa type t7685 that has not been previously reported by other studies.     

Clinical Presentation of Novel Influenza A (H1N1) in Hospitalized Children

Objective

Human pandemic influenza H₁N₁ virus as the cause of febrile respiratory infection ranging from self-limited to severe illness has spread globally during 2009. Signs and symptoms of upper and lower respiratory tract involvement, fever, sore throat, rhinitis, myalgia, malaise, headache, chills and fatigue are common. In this article we report the clinical presentation of Influenza A (H₁N₁) in our hospitalized children.

Methods

Between September and October 2009, all children requiring hospitalization for suspected H₁N₁ infection were transferred to Pediatric Infectious Diseases ward. For all patients the throat swab was taken for PCR testing to confirm or exclude the diagnosis of H₁N₁ Influenza A. Case patients consisted of H₁N₁-positive patients. Age, sex, symptoms, signs, laboratory data, CXR changes, details of therapy, duration of admission and patient outcome were documented.

Findings

Twenty patients were H₁N₁ positive. Mean age of the patients was 65.50±9.8 months. Fever and coughs were with 55% the most commonly reported symptoms. Other presentations included vomiting (55%), abdominal pain (25%), cyanosis and dyspnea (5%), body ache (40%), rhinorrhea (80%), sore throat (35%), head stiffness (5%) and loss of conciousness (5%). The median temperature of the patients was 38.5°C. Chest X-Ray changes were noted in 13 out of 20 patients (65%). Mean leukocyte and platelet was 6475 and 169000 respectively. Seventeen (85%) patients were treated with Oseltamivir, 3 patients received adjuvant antibiotics. The mean duration of admission was 3 days. Three patients required intensive care support and all of them expired due to superinfection.

Conclusion

Our data confirm that the presentation of influenza in children is variable and 2009 H₁N₁ influenza may cause leucopenia and thrombocytopenia.     

Comparison of GnRH antagonist with long GnRH agonist protocol after OCP pretreatment in PCOs patients

Purpose  

To evaluate the efficacy of GnRH antagonist in comparison with the GnRH agonist protocol in OCP pretreated polycystic ovary syndrome (PCOs) patients undergoing their first ART cycle.     

Immediate Exposure to TNF-α Activates Dendritic Cells Derived from Non-Purified Cord Blood Mononuclear Cells

Background: Tumor necrosis factor alpha (TNF-α) is a primary mediator of immune regulation and might be required in the early stages of DC development from CD34+ cells. However, details of optimal timing of exposure to TNF-α in DC development process in monocytes or non-purified hematopoitic cells are still lacking and clear benefits of this approach to the development of DCs remain to be validated. Objective: To evaluate the effect of early and late exposure to TNF-α on DC devel-opment from non-purified cord blood mononuclear cells. Methods: To define the ef-fects of early exposure to TNF-α on cord blood mononuclear cells, we cultured UCB-MNC in the presence of SCF, Flt3L, GM-CSF and IL-4 for 14 days and matured them for an extra 4 days. TNF-α was added on day 0, 7 and 14 in TNF-α + group, and only on day 14 in TNF-α - group where it was used only as a maturation factor. Results: Immediate exposure to TNF-α was shown to: (1) enhance the survival of cells in the first week of culture; (2) produce mature DCs with higher maturation markers (CD80, CD83, CD86 and HLA-DR); and (3) increase secretion of IL-12 by mature DCs. In contrast, delayed exposure to TNF-α stimulate mature DCs with less purity producing a high level of IL-10 and a low level of IL-12. Conclusion: We developed a simple, easy and cost effective method to generate DCs from non-fractionating mononuclear cells in this study. Also we confirm the presence of a large number of functional DCs under inflammatory conditions, where local concentrations of TNF-α were high.     

Retinoic acid synergistically enhances the melanocytotoxic and depigmenting effects of monobenzylether of hydroquinone in black guinea pig skin

Monobenzylether of hydroquinone (MBEH) has long been utilized for the depigmentation therapy of patients with extensive vitiligo. In this approach, the normally pigmented areas surrounding vitiligo lesions are depigmented to achieve a uniform skin tone. One of the important disadvantages of MBEH therapy, however, is the resistance of a considerable number of vitiligo patients against the depigmenting effect of this agent. We have previously proposed that the glutathione-dependent cytoprotection of melanocytes can be impaired through the inhibition of the enzyme glutathione S-transferase by retinoic acid (RA). The combination of RA with melanocytotoxic agents could thus lead to increased susceptibility of melanocytes to such compounds. In this study we have shown, for the first time, that the melanocytotoxic and depigmenting effects of MBEH are synergistically enhanced when it is combined with RA. The treatment of black guinea pig skin with RA (0.025%) alone induced no significant changes in the number of epidermal melanocytes and no skin depigmentation. On the other hand, MBEH (10%) produced mild to moderate skin depigmentation and reduced the average number of melanocytes from 76 (+/-5)/field (magnification: x 40) in control sites, to 42 (+/-6)/field in the depigmented skin. The RA (0.025%)-MBEH (10%) combination, however, produced a complete degree of depigmentation in the majority of treated sites after 10 days of application and reduced the average number of melanocytes to only 6 (+/-6)/field. RA-MBEH combination serves as a very potent skin depigmenting formula and now awaits future assessments of its potential use for the treatment of extensive vitiligo.     

Evaluation of appropriate usage of fresh frozen plasma: Results of a regional audit in Iran

BackgroundFresh frozen plasma (FFP) is a major source of coagulation factor replacement therapy for patients with clotting factor deficiency. Although FFP is readily available for use in clinical practice its administration isn’t without risk. Studies on the use of FFP reveal that it is often overused or inappropriately used. We undertook an audit to assess the appropriateness of FFP transfusion in Gorgan’s hospitals.MethodsThis was a retrospective, audit done at 5 hospitals in Gorgan city regarding the use of 1592 units of FFP issued to 346 patients from March 2006 to March 2007. The appropriateness of FFP transfusion was analyzed according to British Council for Standardization in Hematology (BCSH) Guidelines 2004.ResultsIn this audit we identified a high rate of inappropriate FFP usage (53% of transfusion episodes). Most ‘Inappropriate’ FFP usage occurred when there was active bleeding, with normal (or unmeasured) coagulation tests (30% of transfusion episodes). In only 66% of FFP-transfused patients were coagulation variable measured at any point in the hospital episode.ConclusionInappropriate usage of FFP is often seen in medical facility and the right solution is needed to curb the misuse of this component. Regular utilization audit can identify correctable errors in transfusion practices. Formal education programs and existing information on FFP use should be directed to professionals ordering FFP.