Effectiveness of partner social support predicts enduring psychological distress after hematopoietic stem cell transplantation.

Objective: Hematopoietic stem cell transplant (HSCT) survivors who are 1 to 3 years posttransplant are challenged by the need to resume valued social roles and activities—a task that may be complicated by enduring transplant-related psychological distress common in this patient population. The present study investigated whether transplant survivors who receive adequate social support from their spouse or intimate partner experience lower distress. Method: Effects of receiving a greater quantity of partner support (a common approach to studying enacted support) were compared with effects of receiving more effective partner support (i.e., support that more closely matches their needs in terms of its quantity and quality). Men and women (N = 230) who were 1 to 3 years posttransplant completed measures of partner support quantity (Manne & Schnoll, 2001), partner social support effectiveness (Rini & Dunkel Schetter, 2010), and psychological distress (Brief Symptom Inventory; Derogatis & Spencer, 1982). Potential medical and sociodemographic confounds were controlled in analyses. Results: As hypothesized, survivors reported less distress when they received more effective partner support (p     

Clarification of a wheat straw‐derived medium with ion‐exchange resins for xylitol crystallization

BACKGROUND: Xylitol bioproduction from lignocellulosic residues comprises hydrolysis of the hemicellulose, detoxification of the hydrolysate, bioconversion of the xylose, and recovery of xylitol from the fermented hydrolysate. There are relatively few reports on xylitol recovery from fermented media. In the present study, ion‐exchange resins were used to clarify a fermented wheat straw hemicellulosic hydrolysate, which was then vacuum‐concentrated and submitted to cooling in the presence of ethanol for xylitol crystallization. RESULTS: Sequential adsorption into two anion‐exchange resins (A‐860S and A‐500PS) promoted considerable reductions in the content of soluble by‐products (up to 97.5%) and in medium coloration (99.5%). Vacuum concentration led to a dark‐colored viscous solution that inhibited xylitol crystallization. This inhibition could be overcome by mixing the concentrated medium with a commercial xylitol solution. Such a strategy led to xylitol crystals with up to 95.9% purity. The crystallization yield (43.5%) was close to that observed when using commercial xylitol solution (51.4%). CONCLUSION: The experimental data demonstrate the feasibility of using ion‐exchange resins followed by cooling in the presence of ethanol as a strategy to promote the fast recovery and purification of xylitol from hemicellulose‐derived fermentation media. Copyright © 2008 Society of Chemical Industry     

Modeling the Accumulation of Degradable Polymer Drug Carriers in the Brain

The blood–brain barrier (BBB) limits the access of drugs to the brain. Intensive research is being conducted on the development of nanoparticulate drug carriers that mediate transfer across the BBB. A question that has been neglected so far is the potential accumulation of the carrier in the brain upon long‐term exposure. Here, we address this question by implementing a kinetic model to relate drug loading, required concentration of drug in the brain, and drug clearance to the degradation half‐life of the carrier. As a test case with clinical relevance we chose poly‐lactic‐co‐glycolic‐acid (PLGA) as a carrier material and a chemotherapeutic for which the required parameters could be recovered from the literature. For methotrexate with a drug load of 8.5 %, a required concentration of free drug of 1 μm , a release from PLGA of 6 hours, a drug clearance from the brain of 3 hours and a half‐life of polymer degradation of 28 days, a steady‐state accumulation of 1.3 g polymer would be reached in the brain (1.5 L) after seven months. While this number is surprisingly small, further physiological research is warranted to assess to which degree this will be in a tolerable range.     

Surface morphology of Diplodon expansus (Küster, 1856; Mollusca, Bivalvia, Hyriidae) gill filaments after exposure to environmentally relevant concentrations of atrazine herbicide

Brazilian endemic species Diplodon expansus (Küster, 1856) is found in freshwater bodies in the country's southeast, in large anthropogenic influence regions especially with an extensive agriculture emphasis. One of the main pesticides used in the species occurrence region is the atrazine herbicide, which has a great contamination potential in the aquatic environment. Therefore, several studies into its toxicity in aquatic systems have been developed. However, the tested concentrations are usually very high and rarely found in the environment and the short-term exposure responses in other aquatic organisms such as native bivalves are still scarce. Thus, this study sought to consider the potential effects of environmentally realistic concentrations of atrazine herbicide on the surface morphology of gill filaments of the bivalve D. expansus under laboratory-controlled conditions after short-term exposure. None of the animals died before the end of the experiment. The main alterations were observed on the frontal surface of filaments, which include mucus accumulation, cilia loss, and disruption. Mucus increased secretion and accumulation in the frontal filaments region preceded as a protective mechanism. Cilia loss and disruption on the frontal surface of the gill filament indicated that ciliated frontal cells were more sensitive to atrazine exposure and these alterations may cause gills functional damages, compromising the uptake of food particles and respiration. Therefore, higher sublethal concentrations of atrazine may compromise the survival and consequently the population of D. expansus in agriculture areas after a longer period of continuous exposure.     

Fluorescence Lifetime Imaging Microscopy (FLIM) of Intracellular Transport by Means of Doubly Labelled siRNA Architectures

For monitoring the intracellular pathway of small interfering RNA (siRNA), both strands were labelled at internal positions by two ATTO dyes as an interstrand Förster resonance energy transfer pair. siRNA double strands show red emission and a short donor lifetime as readout, whereas siRNA antisense single strands show green emission and a long donor lifetime. This readout signals if GFP silencing can be expected (green) or not (red). We attached both dyes to three structurally different alkyne anchors by postsynthetic modifications. There is only a slight preference for the ribofuranoside anchors with the dyes at their 2’-positions. For the first time, the delivery and fate of siRNA in live HeLa cells was tracked by fluorescence lifetime imaging microscopy (FLIM), which revealed a clear relationship between intracellular transport using different transfection methods and knockdown of GFP expression, which demonstrates the potential of our siRNA architectures as a tool for future development of effective siRNA.     

Nanosilver induces minimal lung toxicity or inflammation in a subacute murine inhalation model

Background

Multi-walled carbon nanotubes (MWCNTs) are new manufactured nanomaterials with a wide spectrum of commercial applications. To address the hypothesis that MWCNTs cause persistent pulmonary pathology, C57BL/6J mice were exposed by pharyngeal aspiration to 10, 20, 40 or 80 μg of MWCNTs (mean dimensions of 3.9 μm × 49 nm) or vehicle. Lungs were preserved at 1, 7, 28 and 56 days post- exposure to determine the potential regions and target cells for impact by MWCNT lung burden. Morphometric measurement of Sirius Red staining was used to assess the connective tissue response.

Results

At 56 days post-exposure, 68.7 ± 3.9, 7.5 ± 1.9 and 22.0 ± 5.1 percent (mean ± SE, N = 8) of the MWCNT lung burden were in alveolar macrophages, alveolar tissue and granulomatous lesions, respectively. The subpleural tissues contained 1.6% of the MWCNT lung burden. No MWCNTs were found in the airways at 7, 28 or 56 days after aspiration The connective tissue in the alveolar interstitium demonstrated a progressive increase in thickness over time in the 80 μg exposure group (0.12 ± 0.01, 0.12 ± 0.01, 0.16 ± 0.01 and 0.19 ± 0.01 μm for 1, 7, 28 and 56 days post-exposure (mean ± SE, N = 8)). Dose-response determined at 56 days post-exposure for the average thickness of connective tissue in alveolar septa was 0.11 ± 0.01, 0.14 ± .02, 0.14 ± 0.01, 0.16 ± 0.01 and 0.19 ± 0.01 μm (mean ± SE, N = 8) for vehicle, 10, 20, 40 and 80 μg dose groups, respectively.

Conclusions

The distribution of lung burden was predominately within alveolar macrophages with approximately 8% delivery to the alveolar septa, and a smaller but potentially significant burden to the subpleural tissues. Despite the relatively low fraction of the lung burden being delivered to the alveolar tissue, the average thickness of connective tissue in the alveolar septa was increased over vehicle control by 45% in the 40 μg and 73% in the 80 μg exposure groups. The results demonstrate that MWCNTs have the potential to produce a progressive, fibrotic response in the alveolar tissues of the lungs. However, the increases in connective tissue per μg dose of MWCNTs to the interstitium are significantly less than those previously found for single-walled carbon nanotubes (SWCNTs).     

Single-chain Fv multimers of the anti-neuraminidase antibody NC10: the residue at position 15 in the VL domain of the scFv-0 (VL-VH) molecule is primarily responsible for formation of a tetramer-trimer equilibrium

Single-chain variable fragment of the murine monoclonal antibodyNC10 specific to influenza virus N9 neuraminidase, joined directlyin the V_L to V_H orientation (scFv-0), forms an equilibrium mixtureof tetramer and trimer with the tetramer as the preferred multimericspecies. In contrast, the V_H-V_L isomer was previously shownto exist exclusively as a trimer. Computer-generated trimericand tetrameric scFv models, based on the refined crystal structurefor NC10 Fv domain, were constructed and used to evaluate factorsinfluencing the transition between V_L-V_H trimer and tetramer.These model structures indicated that steric restrictions betweenloops spanning amino acid residues L55–L59 and L13–L17from the two adjacent V_L domains within the V_L-V_H trimer wereresponsible for four scFv-0 molecules assembling to form a tetramer.In particular, leucine at position L15 and glutamate at positionL57 appeared to interfere significantly with each other. Tominimize this steric interference, the site-directed mutagenesistechnique was used to construct several NC10 scFv-0 clones withmutations at these positions. Size-exclusion chromatographicanalyses revealed that several of these mutations resulted inthe production of NC10 scFv-0 proteins with significantly alteredtetramer–trimer equilibrium ratios. In particular, introductionof a polar residue, such as asparagine or threonine, at positionL15 generated a highly stable NC10 scFv-0 trimer.     

Synthesis of Fatty Acetoacetates Under Microwave Irradiation Catalysed by Sulfamic Acid in a Solvent-Free System

The 1,3‐dicarbonyl compounds are important building blocks to obtain products with various biological activities and technological applications. In this work, we used a simple transesterification method to develop fatty acetoacetates in a solvent‐free medium using a green catalyst, sulfamic acid (NH₂SO₃H), under microwave irradiation. The experimental results demonstrate good yields in a short reaction time (13 min), which makes this method an efficient approach to synthesize fatty acetoacetates from a wide range of saturated, unsaturated, and polyunsaturated long chain fatty alcohols, and ricinoleic derivatives. Experiments of recycling of the catalyst were performed and no decrease in catalytic activity of sulfamic acid was observed.