Triblock copolymer based thermoplastic elastomeric gels of a large service temperature range: preparation and characterization

Poly(methyl methacrylate)-block-polybutadiene-block-poly(methyl methacrylate) (MBM) triblock copolymers and their hydrogenated counterparts with poly(ethylene-co-1,2-butylene) midblock (MEBM) were swollen by an aliphatic oil of high boiling point which is a selective solvent for the central block. Thermoreversible gels are accordingly formed by both MBM and MEBM copolymers above a critical polymer content (Cr), which depends on the nature of the midblock and not on the copolymer molecular weight, at least in the investigated range. Cr has been found to be 5 wt.-% for an MBM block copolymer and 2 wt.-% for MEBM copolymers of various molecular weights. Gels of MEBM triblock copolymers exhibit interesting mechanical properties, such as high elongation at break (up to 870%) and high tensile strength (32 kPa). The most interesting feature of the MEBM gels is an upper service temperature as high as 170°C, thus more than 100°C higher than the value (47°C) reported for gels of an SEBS copolymer (S = polystyrene) of comparable molecular weight (100000) and composition (ca. 30 wt.-% hard block). The morphology of MEBM gels was studied by scanning electron microscopy (SEM) and found to be cocontinuous in case of a gel containing 20 wt.-% copolymer.     

Four-dimensional (4D) PET/CT imaging of the thorax

We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four lung cancer patients were monitored by tracking external markers placed on the thorax. A 4D-CT acquisition was performed using a "step-and-shoot" technique, in which computed tomography (CT) projection data were acquired over a complete respiratory cycle at each couch position. The period of each CT acquisition segment was time stamped with an "x-ray ON" signal, which was recorded by the tracking system. 4D-CT data were then sorted into 10 groups, according to their corresponding phase of the breathing cycle. 4D-PET data were acquired in the gated mode, where each breathing cycle was divided into ten 0.5 s bins. For both CT and PET acquisitions, patients received audio prompting to regularize breathing. The 4D-CT and 4D-PET data were then correlated according to respiratory phase. The effect of 4D acquisition on improving the co-registration of PET and CT images, reducing motion smearing, and consequently increase the quantitation of the SUV, were investigated. Also, quantitation of the tumor motions in PET, and CT, were studied and compared. 4D-PET with matching phase 4D-CTAC showed an improved accuracy in PET-CT image co-registration of up to 41%, compared to measurements from 4D-PET with clinical-CTAC. Gating PET data in correlation with respiratory motion reduced motion-induced smearing, thereby decreasing the observed tumor volume, by as much as 43%. 4D-PET lesions volumes showed a maximum deviation of 19% between clinical CT and phase- matched 4D-CT attenuation corrected PET images. In CT, 4D acquisition resulted in increasing the tumor volume in two patients by up to 79%, and decreasing it in the other two by up to 35%. Consequently, these corrections have yielded an increase in the measured SUV by up to 16% over the clinical measured SUV, and 36% over SUV's measured in 4D-PET with clinical-CT Attenuation Correction (CTAC) SUV's. Quantitation of the maximum tumor motion amplitude, using 4D-PET and 4D-CT, showed up to 30% discrepancy between the two modalities. We have shown that 4D PET/CT is clinically a feasible method, to correct for respiratory motion artifacts in PET/CT imaging of the thorax. 4D PET/CT acquisition can reduce smearing, improve the accuracy in PET-CT co-registration, and increase the measured SUV. This should result in an improved tumor assessment for patients with lung malignancies.     

Trust and distrust among Appalachian women regarding cervical cancer screening: a qualitative study

Objective

To explore Appalachian women's perceptions of trust and distrust of healthcare providers and the medical care system as they relate to views about cervical cancer and screening.

Methods

Thirty-six Ohio Appalachia female residents participated in community focus groups conducted by trained facilitators. Discussion topics included factors related to cervical cancer, and the issues of trust and distrust in medical care. The tape-recorded focus groups were transcribed and analyzed to identify salient themes.

Results

Five themes emerged related to trust in healthcare. Patient-centered communication and encouragement from a healthcare provider led women to trust their physicians and the medical care system. In contrast, lack of patient-centered communication by providers and perceptions of poor quality of care led to distrust. Physician gender concordance also contributed to trust as women reported trust of female physicians and distrust of male physicians; trust in male physicians was reported to be increased by the presence of a female nurse.

Conclusions

Important factors associated with trust and distrust of providers and the medical care system may impact health-seeking behaviors among underserved women.

Practice implications

Opportunities to improve patient-centered communication around the issues of prevention and cervical cancer screening (such as providing patient-focused information about access to appropriate screening tests) could be used to improve patient care and build patients’ trust.     

Evaluation of the solid phase competition ELISA for detecting antibodies against the six foot-and-mouth disease virus non-O serotypes

The solid-phase competition ELISA (SPCE) has been evaluated in both screening and titration assay formats for detecting antibodies against foot-and-mouth disease virus (FMDV) for the six non-O serotypes A, C, SAT 1, SAT 2, SAT 3 and Asia 1. Cut-off values were determined as a percentage inhibition of 40 for the SAT serotypes and 50 for serotypes A, C and Asia 1, which gave rise to specificity values ranging from 99.41% to 99.9% for the different serotypes. The relative sensitivity between the SPCE and LPBE/virus neutralisation test was 100%/109%. Antiserum titres derived by the SPCE for samples of serotypes O, A(22) and Asia 1 were more than 11, 1 and 5 times of those determined by virus neutralisation test, respectively. This study indicated that the non-type O SPCEs have sufficient sensitivities and specificities for use as serological diagnostic tests for the qualitative and quantitative detection of antibodies against FMDV.     

Microenvironments engineered by inkjet bioprinting spatially direct adult stem cells toward muscle- and bone-like subpopulations

In vivo, growth factors exist both as soluble and as solid-phase molecules, immobilized to cell surfaces and within the extracellular matrix. We used this rationale to develop more biologically relevant approaches to study stem cell behaviors. We engineered stem cell microenvironments using inkjet bioprinting technology to create spatially defined patterns of immobilized growth factors. Using this approach, we engineered cell fate toward the osteogenic lineage in register to printed patterns of bone morphogenetic protein (BMP) 2 contained within a population of primary muscle-derived stem cells (MDSCs) isolated from adult mice. This patterning approach was conducive to patterning the MDSCs into subpopulations of osteogenic or myogenic cells simultaneously on the same chip. When cells were cultured under myogenic conditions on BMP-2 patterns, cells on pattern differentiated toward the osteogenic lineage, whereas cells off pattern differentiated toward the myogenic lineage. Time-lapse microscopy was used to visualize the formation of multinucleated myotubes, and immunocytochemistry was used to demonstrate expression of myosin heavy chain (fast) in cells off BMP-2 pattern. This work provides proof-of-concept for engineering spatially controlled multilineage differentiation of stem cells using patterns of immobilized growth factors. This approach may be useful for understanding cell behaviors to immobilized biological patterns and could have potential applications for regenerative medicine.     

The role of DMQ(9) in the long-lived mutant clk-1

IntroductionUbiquinone (UQ) is a redox active lipid that transfers electrons from complex I or II to complex III in the electron transport chain (ETC). The long-lived Caenorhabditis elegans mutant clk-1 is unable to synthesize its native ubiquinone, and accumulates high amounts of its precursor, 5-demethoxyubiquinone-9 (DMQ₉). In clk-1, complexes I–III activity is inhibited while complexes II–III activity is normal. We asked whether the complexes I–III defect in clk-1 was caused by: (1) a defect in the ETC; (2) an inhibitory effect of DMQ₉; or (3) a decreased amount of ubiquinone.MethodsWe extracted the endogenous quinones from wildtype (N2) and clk-1 mitochondria, replenished them with exogenous ubiquinones, and measured ETC activities.ResultsReplenishment of extracted mutant and wildtype mitochondria resulted in equal enzymatic activities for complexes I–III and II–III ETC assays. Blue native gels showed that supercomplex formation was indistinguishable between clk-1 and N2. The addition of a pentane extract from clk-1 mitochondria containing DMQ₉ to wildtype mitochondria specifically inhibited complexes I–III activity. UQ in clk-1 mitochondria was oxidized compared to N2.DiscussionOur results show that no measurable intrinsic ETC defect exists in clk-1 mitochondria. The data indicate that DMQ₉ specifically inhibits electron transfer from complex I to ubiquinone.     

Service users’ attributes associated with the uptake of medical versus surgical abortion at public health facilities in Vietnam

Objective

To investigate the attributes of service users associated with uptake of medical abortion (MA) versus manual vacuum aspiration (MVA) at public health facilities in Vietnam.

Methods

Structured exit interviews were conducted among women who underwent termination at 62 public health facilities in Hanoi, Khanh Hoa, and Ho Chi Minh City (HCMC) between August and December 2011. Data on sociodemographic, abortion-related, and service-related factors were compared between women who underwent MVA versus MA.

Results

Overall, 1233 women completed the study survey: 541 (43.9%) from Hanoi; 163 (13.2%) from Khanh Hoa; and 529 (42.9%) from HCMC. Almost one-quarter of women (23.1%) had chosen MA. After controlling for sociodemographic factors, women living in Khanh Hoa (odds ratio [OR], 13.4; 95% confidence interval [CI], 5.3–33.8) and HCMC (OR, 5.8; 95% CI, 2.1–15.9) were more likely to have undergone MA than women in Hanoi. Older women were less likely to have undergone MA (P < 0.05), and those who had previously heard of MA were twice as likely to have undergone MA (P = 0.020).

Conclusion

Uptake of MA was lower than that of MVA and varied by province. Women in Vietnam will make their own judgment about which method to choose if they have prior knowledge of both.     

A prognostic immune predictor,HLA-DRA,plays diverse roles in non-muscle invasive and muscle invasive bladder cancer

BackgroundThere is an increasing demand for prognostic immune biomarkers of cancer. The prognostic significance of immune markers has been shown for various cancers, but biomarkers of bladder cancer (BCa) have not been fully evaluated. To clarify the role of human leukocyte antigen DR alpha chain (HLA-DRA) in BCa development, we examined expression of HLA-DRA mRNA in tissue samples of non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC).Materials and MethodsTissues of 96 NMIBC, 43 MIBC and 59 controls comprising noncancerous BCa surrounding tissues were used to examine the expression of HLA-DRA gene by real-time polymerase chain reaction. The expression of up-stream genes regulating HLA-DRA were also measured to explain the role of HLA-DRA in BCa.ResultsPatients with high grade NMIBC showed higher expression of HLA-DRA than those with low grade NMIBC (P < 0.05). In addition, NMIBC patients who progressed to MIBC showed high expression of HLA-DRA mRNA. Kaplan-Meier analysis showed that NMIBC patients with low expression of HLA-DRA had better progression-free survival than those with high expression (P = 0.004). Moreover, the expression of genes regulating HLA-DRA varied in NMIBC and MIBC, indicating a different immunoregulation effect of HLA-DRA in both cancers.ConclusionsHigh expression of HLA-DRA in NMIBC patients has implications for patient stratification strategies, as well as for BCa tumor immunology.     

Does exercise evoke neurological symptoms in healthy subjects?

Concussion is a common injury in collision sports and is evidenced by a variety of signs and symptoms. The recording of neurological symptoms is an important component of screening for a concussion and in return-to-play decisions. However similar symptoms are prevalent in the general population and are reported to be associated with participation in physical activities. The purpose of this study was to document the neurological symptoms reported by healthy individuals following controlled bouts of exercise. A crossover randomised design with 2 levels of exercise intensity, moderate intensity and high intensity, each of 15 min duration was used. Participants completed a standardised postconcussion symptom checklist prior to exercise (pre), immediately following exercise (post-1) and again after 15 min of rest (post-2). 60 participants were recruited into the study. A summed symptom score was calculated and analysed with a 2-way repeated measures ANOVA procedure. The intensity × time interaction (F_2,118 = 23.94, p < 0.001) demonstrated a significant increase in symptom scores for the high intensity condition immediately following exercise (p < 0.001). Although the moderate intensity showed a similar trend this was not significant. These findings suggest that sports medicine professionals need to be aware of the effect of exercise on symptom reporting when assessing and in making return-to-play decisions.