In bone tissue engineering, cell-scaffold constructs are used to stimulate complete, functional tissue replacement that does not occur naturally in critical-size defects. In this report, we describe ...the application potential of poly (L-co-D,L lactic acid)-PLDLA 70/30, synthesized in house as constructs loaded with osteoblast-like cells on bone tissue engineering. In vitro biological results show that the porogen leached PLDLA scaffolds are cytocompatible with osteoblast cells, able to stimulate significant cells growth during the first 14 days of culture, during which the morphology and cell behavior of osteoblasts cultured on the scaffolds were monitored by scanning electron microscopy (SEM). In vivo, PLDLA constructs were implanted in 5 mm bilateral critical-size defects created in rat-calvariae and then evaluated histologically 8 and 12 weeks after implantation. The histological results showed that PLDLA constructs supported the growth of new tissue, with a degradation rate close to that of native bone formation and decrease of inflammatory response over time of implantation. These data provide evidences that the synthesized PLDLA polymer has application potential as construct for bone tissue engineering.
To investigate whether exposure to phenolic resins (PR) is associated with quantitative olfactory disorders (QOD), a cross-sectional study of self-reported olfactory impairment (SROI) was performed ...in occupationally exposed subjects.
Sixty-six workers (45 males, 21 females) at the age (mean ± standard deviation) of 39.8±10.15 years old were divided into 3 exposure groups on the basis of biological exposure indices (BEI) for urinary phenols. It was asked whether the sense of smell has been normal or abnormal during the recent 2 months: the participants were eventually divided into self-reported normosmic, hyposmic, hyperosmic groups.
Prevalence of the SROI was 45.5%, with 21 (31.8%) workers complaining about the hyposmia, 12 (18.2%) - anosmia and 9 (13.6%) - hyperosmia. In univariate analyses, female sex was associated with the SROI and the hyperosmia. Highly exposed workers showed the SROI more frequently (odds ratio (OR) = 4.714; 95% confidence interval (CI): 1.077-20.626) than those not exposed (reference) or low exposed (OR = 1.333; 95% CI: 0.416-4.274). In multivariate analyses, female sex was the main risk factor for the SROI (adjusted odds ratio (ORa) = 5.622; 95% CI: 1.525-20.722) and the hyperosmia (ORa = 25.143; 95% CI: 2.379-265.7) but a high exposure to phenol (ORa = 11.133; 95% CI: 1.060-116.9) was the main risk factor for the anosmia.
This study has found slight evidence among the cross-section of chemical industry workers that the exposure to phenol may be associated with the SROI. On the other hand, self-reporting of the QOD may be biased by personal factors and further research with objective measurement is therefore required. Med Pr 2016;67(2):173-186.
Surface modification techniques based on the grafting of chemical functional groups and immobilization of bioactive molecules have been used to improve biocompatibility and clinical performance of ...bioabsorbable scaffolds in tissue engineering and medicine regenerative applications. This study aimed at developing and characterizing a biomimetic surface to stimulate bone regeneration by a simple and low-cost method of surface biofunctionalization of the poly (L-co-D,L lactic acid)-PLDLA scaffolds. The method was obtained by grafting reaction of carboxyl groups (-COOH) on their surface via acrylic acid (AAc) polymerization process, followed by immobilization of collagen type I (Col). Such approach resulted in a surface morphology markedly modified after treatment, with increase of pores and roughness on PLDLA-AAc surfaces and a network of fibrillar collagen deposition in non-specific areas of PLDLA-Col surfaces. The cytocompatibility of collagen-immobilized scaffolds was significantly improved in terms of cellular adhesion, proliferation, collagen synthesis and maintenance of osteoblast-like phenotype, indicating, therefore, the fundamental role of collagen protein over the biological interactions that occur by bio-recognition mimetic mechanisms at biomaterials interface. These results indicate that the surface modification method used here may be useful as a strategy to develop biofunctional scaffolds, which provide a more successful clinical application of biomaterials in the tissue engineering field.
We report an unprecedented iron-catalyzed C-H annulation using readily available 2-vinylbenzofurans as the reaction pattern. The redox-neutral strategy, based on cheap, non-toxic and earth abundant ...iron catalysts, exploits triazole assistance to promote a cascade C-H alkylation, benzofuran ring-opening and insertion into a Fe-N bond, to form highly functionalized isoquinolones. Detailed mechanistic studies supported by DFT calculations fully disclosed the manifold of the iron catalysis.
Abstract Heteroditopic calix6arenes are widely employed macrocycles for the synthesis of pseudo‐oriented interlocked systems and stimuli‐induced molecular machines, among others. Herein, we introduce ...a new calix6arene receptor functionalised with three phenylselenoureido groups. These hydrogen‐bonding donor moieties are able to promote the threading of viologen‐based organic axles inside the macrocyclic cavity to form a stable pseudorotaxane species. Preliminary investigations using 1 H‐NMR measurements and semi‐empirical and DFT studies suggested its further use as a platform for the synthesis of rotaxanes.
Following a new approach, we prepared a nanoink with two separate photothermally responsive absorption bands. One is the localized surface plasmon resonance (LSPR) absorption of gold nanoparticles ...(AuNP, d =17 nm), the second is the absorption band of two cyanine (Cy) dyes, Cy7‐C6 or Cy7‐C11, grafted to the AuNP surface through thiolated bridges of different lengths: the close proximity to the Au surface induces full quenching of the Cy fluorescence, resulting in thermal relaxation on irradiation. Attempts to full coat AuNP with the lipophilic Cy7‐C6 and Cy7‐C11 lead to precipitation from aqueous solutions. We thus prepared AuNP with partial pegylation (30, 50, or 70%), using a long chain thiol‐terminated PEG bearing a ‐COOH function. Addition until saturation of either Cy7‐C6 or Cy7‐C11 to the partially pegylated AuNP gave the AuNP@Cy/PEGX% hybrids (X = 30, 50, 70) that are stable in water and in the water/alcohol mixtures used to prepare the nanoinks. Further overcoating of AuNP@Cy7‐C6/PEG50% with PAH (polyallylamine hydrochloride) avoids LSPR hybridization in the dry nanoink printouts, that present two separate bands. When irradiated with laser sources near their absorption maxima, the printouts of the AuNP@Cy7‐C6/PEG50%@PAH nanoink respond on two channels, giving different temperature increases depending on the irradiation wavelength.
The catalytic asymmetric construction of axially chiral C–N atropisomers remains a formidable challenge due to their low rotational barriers and is largely reliant on toxic, cost-intensive, and ...precious metal catalysts. In sharp contrast, we herein describe the first nickel-catalyzed atroposelective C–H alkylation for the construction of C–N axially chiral compounds with the aid of a chiral heteroatom-substituted secondary phosphine oxide (HASPO)-ligated Ni–Al bimetallic catalyst. A wide range of alkenes, including terminal and internal alkenes, were well compatible with the reaction, providing a variety of benzimidazole derivatives in high yields and enantioselectivities (up to 97:3 e.r.). The key to success was the identification of novel HASPOs as highly effective chiral preligands. Mechanistic studies revealed the catalyst mode of action, and in-depth data science analysis elucidated the key features of the responsible chiral preligands in controlling the enantioselectivity.
Sepsis is a common and severe complication in premature neonates, particularly those with very low birth weight (VLBW) (<1500 g). Whether lactoferrin, a mammalian milk glycoprotein involved in innate ...immune host defenses, can reduce the incidence of sepsis is unknown. In animal models, the probiotic Lactobacillus rhamnosus GG (LGG) enhances the activity of lactoferrin but has not been studied in human infants.
To establish whether bovine lactoferrin (BLF), alone or in combination with LGG, reduces the incidence of late-onset sepsis in VLBW neonates.
Prospective, multicenter, double-blind, placebo-controlled, randomized trial conducted in 11 Italian tertiary neonatal intensive care units. Patients were 472 VLBW infants enrolled from October 1, 2007, through July 31, 2008, and assessed until discharge for development of sepsis.
Infants were randomly assigned to receive orally administered BLF (100 mg/d) alone (n = 153), BLF plus LGG (6 x 10(9) colony-forming units/d) (n = 151), or placebo (n = 168) from birth until day 30 of life (day 45 for neonates <1000 g at birth).
First episode of late-onset sepsis, ie, sepsis occurring more than 72 hours after birth with isolation of any pathogen from blood or from peritoneal or cerebrospinal fluid.
Demographic, clinical, and management characteristics of the 3 groups were similar, including type of feeding and intake of maternal milk. Incidence of late-onset sepsis was significantly lower in the BLF and BLF plus LGG groups (9/153 5.9% and 7/151 4.6%, respectively) than in the control group receiving placebo (29/168 17.3%) (risk ratio, 0.34; 95% confidence interval, 0.17-0.70; P = .002 for BLF vs control and risk ratio, 0.27; 95% confidence interval, 0.12-0.60; P < .001 for BLF plus LGG vs control). The decrease occurred for both bacterial and fungal sepsis. No adverse effects or intolerances to treatment occurred.
Compared with placebo, BLF supplementation alone or in combination with LGG reduced the incidence of a first episode of late-onset sepsis in VLBW neonates.
isrctn.org Identifier: ISRCTN53107700.
Abstract We report an unprecedented iron‐catalyzed C−H annulation using readily available 2‐vinylbenzofurans as the reaction pattern. The redox‐neutral strategy, based on cheap, non‐toxic, and ...earth‐abundant iron catalysts, exploits triazole assistance to promote a cascade C−H alkylation, benzofuran ring‐opening and insertion into a Fe−N bond, to form highly functionalized isoquinolones. Detailed mechanistic studies supported by DFT calculations fully disclosed the manifold of the iron catalysis.
To investigate whether exposure to inhibitors of gastric acidity, such as H2 blockers or proton pump inhibitors, can independently increase the risk of infections in very low birth weight (VLBW) ...preterm infants in the neonatal intensive care unit.
This is a secondary analysis of prospectively collected data from a multicenter, randomized controlled trial of bovine lactoferrin (BLF) supplementation (with or without the probiotic Lactobacillus rhamnosus GG) vs placebo in prevention of late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) in preterm infants. Inhibitors of gastric acidity were used at the recommended dosages/schedules based on the clinical judgment of attending physicians. The distribution of days of inhibitors of gastric acidity exposure between infants with and without LOS/NEC was assessed. The mutually adjusted effects of birth weight, gestational age, duration of inhibitors of gastric acidity treatment, and exposure to BLF were controlled through multivariable logistic regression. Interaction between inhibitors of gastric acidity and BLF was tested; the effects of any day of inhibitors of gastric acidity exposure were then computed for BLF-treated vs -untreated infants.
Two hundred thirty-five of 743 infants underwent treatment with inhibitors of gastric acidity, and 86 LOS episodes occurred. After multivariate analysis, exposure to inhibitors of gastric acidity remained significantly and independently associated with LOS (OR, 1.03; 95% CI, 1.008-1.067; P = .01); each day of inhibitors of gastric acidity exposure conferred an additional 3.7% odds of developing LOS. Risk was significant for Gram-negative (P < .001) and fungal (P = .001) pathogens, but not for Gram-positive pathogens (P = .97). On the test for interaction, 1 additional day of exposure to inhibitors of gastric acidity conferred an additional 7.7% risk for LOS (P = .003) in BLF-untreated infants, compared with 1.2% (P = .58) in BLF-treated infants.
Exposure to inhibitors of gastric acidity is significantly associated with the occurrence of LOS in preterm VLBW infants. Concomitant administration of BLF counteracts this selective disadvantage.
isrctn.org: ISRCTN53107700.
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