Lack of association of angiotensin I-converting enzyme gene polymorphism and premature myocardial infarction in Mauritian Indians

Eighty-five young Mauritian Indians, male survivors of premature myocardial infarction (MI) and thus belonging to a high risk group, were compared with 108 stringently selected controls for a possible association between premature MI and an insertion/deletion (I/D) polymorphism in the gene encoding angiotensin I-converting enzyme (ACE). The frequency of the D allele was 0.42 in the MI group and 0.43 in the control group, and thus no association between I/D polymorphism of ACE with susceptibility to early-onset MI was found in this population group. Other gene components of the renin-angiotensin system and lipid metabolism need to be explored to understand the genetic factors involved in causing MI at an early age.     

Utilizing Edible Agar as a Carrier for Dual Functional Doxorubicin-Fe3O4 Nanotherapy Drugs

The purpose of this study was to use agar as a multifunctional encapsulating material to allow drug and ferromagnetism to be jointly delivered in one nanoparticle. We successfully encapsulated both Fe₃O₄ and doxorubicin (DOX) with agar as the drug carrier to obtain DOX-Fe₃O₄@agar. The iron oxide nanoparticles encapsulated in the carrier maintained good saturation of magnetization (41.9 emu/g) and had superparamagnetism. The heating capacity test showed that the specific absorption rate (SAR) value was 18.9 ± 0.5 W/g, indicating that the ferromagnetic nanoparticles encapsulated in the gel still maintained good heating capacity. Moreover, the magnetocaloric temperature could reach 43 °C in a short period of five minutes. In addition, DOX-Fe₃O₄@agar reached a maximum release rate of 85% ± 3% in 56 min under a neutral pH 7.0 to simulate the intestinal environment. We found using fluorescent microscopy that DOX entered HT-29 human colon cancer cells and reduced cell viability by 66%. When hyperthermia was induced with an auxiliary external magnetic field, cancer cells could be further killed, with a viability of only 15.4%. These results show that agar is an efficient multiple-drug carrier, and allows controlled drug release. Thus, this synergic treatment has potential application value for biopharmaceutical carrier materials.     

Chlamydia trachomatis infection among HIV-infected women attending an AIDS clinic in the city of Manaus,Brazil

This was a cross-sectional study aimed to determine the prevalence of and to identify risk factors for Chlamydia trachomatis (CT) among human immunodeficiency virus (HIV)-infected women attending the acquired immunodeficiency syndrome (AIDS) clinic in the city of Manaus, Brazil, in 2009-2010. Participants answered a questionnaire containing demographic, epidemiological, and clinical data. A genital specimen was collected during examination to detect CT-DNA by hybrid capture, and blood samples were taken to determine CD4⁺T and HIV viral load. There were 329 women included in the study. Median age was 32 years (IQR = 27-38) and median schooling was nine years (IQR = 4-11). The prevalence of CT was 4.3% (95%CI: 2.1-6.5). Logistic regression analysis showed that age between 18-29 years [OR = 4.1(95%CI: 1.2-13.4)] and complaint of pelvic pain [OR = 3.7 (95%CI: 1.2-12.8)] were independently associated with CT. The use of condom was inversely associated with CT [OR = 0.39 (95%CI: 0.1-0.9)]. The results showed that younger women who did not use condoms are at a higher risk for CT. Screening for sexually transmitted infections must be done routinely and safe sexual practices should be promoted among this population.     

Decomposition of spontaneous fluctuations in tumour oxygenation using BOLD MRI and independent component analysis

Background:

Solid tumours can undergo cycles of hypoxia, followed by reoxygenation, which can have significant implications for the success of anticancer therapies. A need therefore exists to develop methods to aid its detection and to further characterise its biological basis. We present here a novel method for decomposing systemic and tumour-specific contributions to fluctuations in tumour deoxyhaemoglobin concentration, based on magnetic resonance imaging measurements.

Methods:

Fluctuations in deoxyhaemoglobin concentration in two tumour xenograft models of colorectal carcinoma were decomposed into distinct contributions using independent component analysis. These components were then correlated with systemic pulse oximetry measurements to assess the influence of systemic variations in blood oxygenation in tumours, compared with those that arise within the tumour itself (tumour-specific). Immunohistochemical staining was used to assess the physiological basis of each source of fluctuation.

Results:

Systemic fluctuations in blood oxygenation were found to contribute to cycling hypoxia in tumours, but tumour-specific fluctuations were also evident. Moreover, the size of the tumours was found to influence the degree of systemic, but not tumour-specific, oscillations. The degree of vessel maturation was related to the amplitude of tumour-specific, but not systemic, oscillations.

Conclusions:

Our results provide further insights into the complexity of spontaneous fluctuations in tumour oxygenation and its relationship with tumour pathophysiology. These observations could be used to develop improved drug delivery strategies.     

Association of mannose-binding lectin gene polymorphism but not of mannose-binding serine protease 2 with chronic severe aortic regurgitation of rheumatic etiology

N-Acetylglucosamine (GlcNAc) is the major immunoepitope of group A streptococcal cell wall carbohydrates. Antistreptococcal antibodies cross-reactive with anti-GlcNAc and laminin are present in sera of patients with rheumatic fever. The cross-reactivity of these antibodies with human heart valvular endothelium and the underlying basement membrane has been suggested to be a possible cause of immune-mediated valve lesion. Mannose-binding lectin (MBL) encoded by the MBL2 gene, a soluble pathogen recognition receptor, has high affinity for GlcNAc. We postulated that mutations in exon 1 of the MBL2 gene associated with a deficient serum level of MBL may contribute to chronic severe aortic regurgitation (AR) of rheumatic etiology. We studied 90 patients with severe chronic AR of rheumatic etiology and 281 healthy controls (HC) for the variants of the MBL2 gene at codons 52, 54, and 57 by using a PCR-restriction fragment length polymorphism-based method. We observed a significant difference in the prevalence of defective MBL2 alleles between patients with chronic severe AR and HC. Sixteen percent of patients with chronic severe AR were homozygotes or compound heterozygotes for defective MBL alleles in contrast to 5% for HC (P = 0.0022; odds ratio, 3.5 [95% confidence interval, 1.6 to 7.7]). No association was detected with the variant of the MASP2 gene. Our study suggests that MBL deficiency may contribute to the development of chronic severe AR of rheumatic etiology.     

Nonadherence to imatinib adversely affects event free survival in chronic phase chronic myeloid leukemia

There is limited data on the impact of treatment interruptions due to nonadherence in patients with chronic phase chronic myeloid leukemia (CP-CML) treated with Imatinib. We looked at factors (including adherence to therapy) affecting the outcome in a large cohort of patients with CP-CML. All the 516 patients received Imatinib free-of-cost through a company sponsored scheme, which mandated regular three monthly visits for drug procurement. Data regarding the disease characteristics, adherence to treatment and outcomes, were obtained from patients records. Unwarranted interruption of treatment for more than 1 week was defined as nonadherence. With a median follow-up of 39 months, the estimated 5-year event free survival (EFS) was 70.8% (95%, CI = 63.3-78.3). Nearly one-third of the patients (29.6%) were found to be nonadherent at some point during their treatment. On univariate analysis, the factors adversely affecting the EFS were prolonged symptom duration before diagnosis, treatment with hydroxyurea for more than 1 month before start of Imatinib, and nonadherence to therapy. Only nonadherence was significant in multivariate analysis (HR1.6; P = 0.048). The 5-year EFS in adherent and nonadherent patients was 76.7% and 59.8% respectively (P = 0.011, log rank test). Nonadherent patients were less likely to achieve complete cytogenetic responses (26% versus 44%; P = 0.004; χ(2) test) at any point. A significant proportion of patients with CP-CML have drug interruptions due to nonadherence during therapy and this compromises the EFS. Adherence to therapy must be included as an important evaluation parameter in all future studies of CML.