[The study of making decision in the timing of delivery for patients of placenta previa through dynamic monitoring the length of cervical canal by perineal ultrasound].

Objective: To investigate the value of dynamic monitoring of cervical canal length by transperineal ultrasonography in the decision-making of the timing of delivery in patients with complete placenta previa, then to provide clinical guidance for complete termination of placenta. Methods: A total of 130 patients with complete placenta previa from 28 weeks to 30 weeks of gestation between January 2014 and October 2017 in Jiaxing Maternal and Child Health Hospital were selected. There were 66 patients in the experimental group and 64 in the control group, closely monitor the patient's vital signs, abdominal pain, abdominal distension, vaginal bleeding and fetal intrauterine conditions. In the experimental group, the length of the cervical canal was monitored by perineal ultrasonography at 2 hours and 12 hours after admission. This led to termination of the pregnancy. The control group was instructed to terminate the timing of pregnancy based on the patient's abdominal pain relief symptoms and vaginal bleeding. Compare the maternal and fetal outcomes of both groups. Results: The length of the cervical canal was (31.3±1.3) mm when the experimental group was admitted to the hospital, and the length of the cervical canal after the use of the retention drugs 2 h and 12 h was (32.1±0.4) mm and (32.2±0.4) mm, respectively.Compared with the length of the cervix at the time of admission. There was no significant change in the length of the cervical canal after the application of the retention drug 2 and 12 h(all P>0.05). The delivery week of 11 patients in the experimental group did not exceed 34 weeks, and 28 cases in the control group, and there was significant difference between the two groups. Compared with the control group, the difference of birth rate did not exceed 34 weeks, birth weight and hospitalization time decreased significantly (all P<0.05). However, there was no significant difference in maternal outcomes between the two groups. Conclusion: Through monitoring the length of the cervical canal by perineal ultrasound can make a better decision for the patients of complete placenta previa to chose the time of delivery.

Isolation and identification of the immune-relevant ribosomal protein L10 (RPL10/QM-like gene) from the large yellow croaker Pseudosciaena crocea (Pisces: Sciaenidae).

In order to investigate the immune role of ribosomal protein L10 (RPL10/QM-like gene) in marine fish, we challenged the large yellow croaker Pseudosciaena (= Larimichthys) crocea, the most important marine fish culture species in China, by injection with a mixture of the bacteria Vibrio harveyi and V. parahaemolyticus (3:1 in volume). Microarray analysis and real-time PCR were performed 24 and 48 h post-challenge to isolate and identify the QM-like gene from the gill P. crocea (designated PcQM). The expression level of the PcQM gene did not changed significantly at 24 h post-challenge, but was significantly downregulated at 48 h post-challenge, suggesting that the gene had an immune-modulatory effect in P. crocea. Full-length PcQM cDNA and genomic sequences were obtained by rapid amplification of cDNA ends (RACE)-PCR. The sequence of the PcQM gene clustered together with those of other QM-like genes from other aquatic organisms, indicating that the QM-like gene is highly conserved in teleosts.

Molecular characterization and structure analysis of RPL10/QM-like protein from the red drum Sciaenops ocellatus (Sciaenidae).

The QM-like gene encodes a ribosomal protein L10. Besides housekeeping roles in protein synthesis, QM-like proteins have multiple extraribosomal functions during cell growth, cell differentiation and apoptosis. We obtained the full-length cDNA of QM-like protein (designated as SoQM) from the salt water game fish Sciaenops ocellatus, using RACE-PCR. The sequence consists of 740 bp, encoding 215-amino acid residues with 24.60 kDa. The AA sequence of the SoQM protein contains a series of functional motifs that belong to the QM family signature, which is conserved among different species. The SoQM gene contains five introns and six exons. The expression pattern of SoQM as determined by RT-PCR indicated that SoQM mRNA was expressed in all tissues tested, including brain, gill, head-kidney, intestine, stomach, heart, spleen, blood, muscle, and gonads. The phylogenetic tree constructed with MEGA 4.0 showed that SoQM clusters together with that of other fish. It was found that the sequences of the SoQM gene are highly conserved, suggesting the fundamental and critical functions of SoQM in S. ocellatus. The three-dimensional structure of the SoQM protein core domain (4~169) was predicted by the Swiss-Model program. Compared with QM proteins in other species, the main structure of SoQM protein was conserved, while the C-terminal domain was different from other QM-like proteins. Prediction of the three-dimensional structure of SoQM would provide valuable insight into the molecular basis of protein function, allowing an effective design of experiments, such as site-directed mutagenesis, studies of disease-related mutations or structure-based design of specific inhibitors.

Corrosion fatigue behaviors of two biomedical Mg alloys - AZ91D and WE43 - In simulated body fluid.

Magnesium alloys have been recently developed as biodegradable implant materials, yet there has been no study concerning their corrosion fatigue properties under cyclic loading. In this study the die-cast AZ91D (A for aluminum 9%, Z for zinc 1% and D for a fourth phase) and extruded WE43 (W for yttrium 4%, E for rare earth mischmetal 3%) alloys were chosen to evaluate their fatigue and corrosion fatigue behaviors in simulated body fluid (SBF). The die-cast AZ91D alloy indicated a fatigue limit of 50MPa at 107 cycles in air compared to 20MPa at 106 cycles tested in SBF at 37°C. A fatigue limit of 110MPa at 107 cycles in air was observed for extruded WE43 alloy compared to 40MPa at 107 cycles tested in SBF at 37°C. The fatigue cracks initiated from the micropores when tested in air and from corrosion pits when tested in SBF, respectively. The overload zone of the extruded WE43 alloy exhibited a ductile fracture mode with deep dimples, in comparison to a brittle fracture mode for the die-cast AZ91D. The corrosion rate of the two experimental alloys increased under cyclic loading compared to that in the static immersion test.

Tissue scaffolds for skin wound healing and dermal reconstruction.

One of the major applications of tissue-engineered skin substitutes for wound healing is to promote the healing of cutaneous wounds. In this respect, many important clinical milestones have been reached in the past decades. However, currently available skin substitutes for wound healing often suffer from a range of problems including wound contraction, scar formation, and poor integration with host tissue. Engineering skin substitutes by tissue engineering approach has relied upon the creation of three-dimensional scaffolds as extracellular matrix (ECM) analog to guide cell adhesion, growth, and differentiation to form skin-functional and structural tissue. The three-dimensional scaffolds can not only cover wound and give a physical barrier against external infection as wound dressing, but also can provide support both for dermal fibroblasts and the overlying keratinocytes for skin tissue engineering. A successful tissue scaffold should exhibit appropriate physical and mechanical characteristics and provide an appropriate surface chemistry and nano and microstructures to facilitate cellular attachment, proliferation, and differentiation. A variety of scaffolds have been fabricated based on materials ranging from naturally occurring ones to those manufactured synthetically. This review discusses a variety of commercial or laboratory-engineered skin substitutes for wound healing. Central to the discussion are the scaffolds/materials, fabrication techniques, and their characteristics associated with wound healing. One specifically highlighted emerging fabrication technique is electrospinning that allows the design and fabrication of biomimetic scaffolds that offer tremendous potential applications in wound healing of skin.

Dependence of alignment direction on magnitude of strain in esophageal smooth muscle cells.

The response of cells in vitro to mechanical forces has been the subject of much research using devices to exert controlled mechanical stimulation on cultured cells or isolated tissue. In this study, esophageal smooth muscle cells were seeded on flexible polyurethane membranes to form a confluent cell layer. The cells were then subjected to uniform cyclic stretch of varying magnitudes at a frequency of approximately five cycles per minute in a custom made mechatronic bioreactor, providing similar strains experienced in the in vivo mechanical environment of the esophagus. The results show that the orientation response is dependent on the magnitude of cyclic stretch applied. Smooth muscle cells showed parallel alignment to the force direction at low cyclic strains (2%) compared to the hill-valley morphology of static controls. At higher strains (5% and 10% magnitude), the cells exhibited a consistent alignment perpendicular to the strain. To our knowledge, this is the first time that the alignment direction's dependence on strain magnitude has been demonstrated. MTS analysis indicated that cell metabolism was reduced when mechanical strain was applied, and proliferation was inhibited by mechanical strain. Protein expression indicates a decrease in smooth muscle alpha-actin, indicative of changes in cell phenotype, an increase in vimentin, which is associated with increased cell motility, and an increase in desmin, indicating differentiation in stimulated cells.

Thermoresponsive comb-shaped copolymer-Si(100) hybrids for accelerated temperature-dependent cell detachment.

Well-defined comb-shaped copolymer-Si(100) hybrids were prepared, via successive surface-initiated atom transfer radical polymerizations (ATRPs) of glycidyl methacrylate (GMA) and N-isopropylacrylamide (NIPAAm), for accelerated cell detachment at a lower temperature. The Si-C bonded comb copolymer consisted of a well-defined (nearly monodispersed) poly(glycidyl methacrylate) (P(GMA)) main chain, a well-defined NIPAAm polymer (P(NIPAAm) block, and well-defined P(NIPAAm) side chains. The ring opening reaction of epoxy groups of the P(GMA) main chain with 2-chloropropionic acid resulted in the immobilization of the alpha-chloroester groups (the ATRP initiators for the NIPAAm side chains) and the concomitant formation of hydroxyl groups. P(NIPAAm) acted as the thermoresponsive side chains of the comb copolymer for control of cell adhesion and detachment, while the P(GMA) main chain with hydroxyl groups provided a local hydrophilic microenvironment. The unique microstructure of the comb copolymer brushes facilitated cell recovery at 20 degrees C (below the lower critical solution temperature (LCST) of P(NIPAAm)) without restraining cell attachments and growth at 37 degrees C. The accelerated detachment of cells indicated that the underlying hydrophilic environment of the comb copolymer brushes contributed to speedy hydration of the P(NIPAAm) segments below the LCST. The thermoresponsive comb copolymer-Si(100) hybrids are potentially useful as adhesion modifiers for cells in silicon-based biomedical devices.

In vitro antibacterial and cytotoxicity assay of multilayered polyelectrolyte-functionalized stainless steel.

Infection of implanted materials by bacteria constitutes one of the most serious complications following prosthetic and implant surgery. In the present study, a new strategy for confering stainless steel with antibacterial property via the alternate deposition of quaternized polyethylenimine (PEI) or quaternized polyethylenimine-silver complex and poly(acrylic acid) (PAA) was investigated. The success of the deposition of the polyelectrolyte multilayers (PEM) and its chemical nature was investigated by static water contact angle and X-ray photoelectron spectroscopy (XPS), respectively. The antibacterial activity was assessed using Escherichia coli (E. coli, a gram-negative bacterium) and Staphylococcus aureus (S. aureus, a gram-positive bacterium). The inhibition of E. coli and S aureus growth on the surface of functionalized films was clearly shown using the LIVE/DEAD Baclight bacterial viability kits and fluorescence microscopy. The cytotoxicity of the PEM to mammalian cells, evaluated by the MTT assay, was shown to be minimal and long-term antibacterial efficacy can be maintained. These results indicate new possibilities for the use of such easily built and functionalized architectures for the functionalization of surfaces of implanted medical devices.

Collagen-coupled poly(2-hydroxyethyl methacrylate)-Si(111) hybrid surfaces for cell immobilization.

To improve the biocompatibility of silicon-based implantable micro- and nanodevices, and to tailor silicon surfaces for controlled cell immobilization, well-defined functional polymer-Si(111) hybrids, consisting of nearly monodispersed poly(2-hydroxyethyl methacrylate [P(HEMA)] with covalently coupled collagen and tethered (Si-C bonded) on the silicon surfaces, were prepared. HEMA was graft polymerized on the hydrogen-terminated Si(111) surface (Si-H surface) via surface-initiated atom transfer radical polymerization (ATRP) to give rise to the Si-g-P(HEMA) hybrid. The active chloride end groups preserved throughout the ATRP process and the chloride groups converted from some (approximately 20%) of the OH groups of the P(HEMA) brushes were used as the leaving groups for nucleophilic reaction with the -NH2 groups of collagen to give rise to the Si-g-P(HEMA)-collagen surface conjugates. These hybrid surfaces were evaluated by culturing 3T3 fibroblasts. The biocompatible Si-g-P(HEMA) hybrid surface resisted attachment and growth of this cell line. The Si-g-P(HEMA)-collagen hybrid surfaces, on the other hand, exhibited good cell adhesion and growth characteristics, and the extent of cell immobilization could be controlled by adjusting the amount of immobilized collagen. Thus, incorporating the collagen-coupled P(HEMA) onto silicon surfaces via robust Si-C bonds may endow the silicon substrates with new and interesting properties for potential applications in silicon-based implantable devices, such as molecular sensors and biochips.

Surface-active and stimuli-responsive polymer--Si(100) hybrids from surface-initiated atom transfer radical polymerization for control of cell adhesion.

A simple two-step method was developed for the covalent immobilization of atom-transfer radical polymerization (ATRP) initiators on the hydrogen-terminated Si(100) (Si-H) surface. Well-defined functional polymer-Si hybrids, consisting of covalently tethered brushes of poly(ethylene glycol) monomethacrylate (PEGMA) polymer, N-isopropylacrylamide (NIPAAm) polymer, and NIPAAm-PEGMA copolymers and block copolymers on Si-H surfaces, were prepared via surface-initiated ATRP. Kinetics study revealed that the chain growth from the silicon surface was consistent with a "controlled" process. Surface cultures of the cell line 3T3-Swiss albino on the hybrids were evaluated. The PEGMA graft-polymerized silicon [Si-g-P(PEGMA)] surface is very effective in preventing cell attachment and growth. At 37 degrees C [above the lower critical solution temperature (LCST, approximately 32 degrees C) of NIPAAm], the seeded cells adhered, spread, and proliferated on the NIPAAm graft polymerized silicon [Si-g-P(NIPAAm)] surface. Below the LCST, the cells detached from the Si-g-P(NIPAAm) surface spontaneously. Incorporation of PEGMA units into the NIPAAm chains of the Si-g-P(NIPAAm) surface via copolymerization resulted in more rapid cell detachment during the temperature transition. The "active" chain ends on the Si-g-P(PEGMA) and Si-g-P(NIPAAm) hybrids were also used as the macroinitiators for the synthesis of diblock copolymer brushes. Thus, not only are the hybrids potentially useful as stimuli-responsive adhesion modifiers for cells in silicon-based biomedical microdevices but also the active chain ends on the hybrid surfaces offer opportunities for further surface functionalization and molecular design.

Organ-specific distribution of AP-1 in AP-1 luciferase transgenic mice during the maturation process.

Activator protein-1 (AP-1), a dimeric complex consisting of proteins encoded by the jun and fos gene families, is a transcription factor induced by a variety of signals including those eliciting proliferation, differentiation, and neoplastic transformation. Although AP-1 has been widely studied in the last decade, physiological levels of AP-1 in different tissues are unclear. In the present study, we analyzed AP-1 activity in several organs (liver, kidney, brain, lung, spleen, heart, skin) of AP-1-luciferase transgenic mice of various ages. Results of these studies indicate that the level of AP-1 in young mice is much higher than that in older mice, and, second, that the skin contains considerably higher levels of AP-1 than other organs. The level of phosphorylated extracellular signal-regulated protein kinase (ERK) in skin was higher in 1- and 2-day-old mice than in mice of other ages. In addition, phosphorylated p38 kinase was high in 2-day-old and 1-wk-old mice, but phosphorylated c-Jun NH(2)-terminal kinase was not detected at any age. AP-1 activity and level of phosphorylated ERKs declined with maturation. These results imply that AP-1 activity mediated through an ERKs-dependent pathway may be involved in skin development.

ERKs and p38 kinases mediate ultraviolet B-induced phosphorylation of histone H3 at serine 10.

Histone H3 is the core protein of the nucleosome. Phosphorylation of H3 involves immediate early gene expression, chromatin remodeling, and chromosome condensation during mitosis. Very recently, Rsk2 or MSK1 kinase-mediated phosphorylation of H3 at serine 10 was reported. In the present study, we show that both ERKs and p38 kinase may mediate ultraviolet B-induced phosphorylation of H3 at serine 10. PD 98059, a MEK1 inhibitor, and SB 202190, a p38 kinase inhibitor, efficiently inhibited ultraviolet B-induced phosphorylation of H3. Phosphorylation of H3 was also inhibited in cells expressing dominant negative mutant (DNM) ERK2 and DNM p38 kinase. In contrast, no inhibition of H3 phosphorylation in Jnk1 or Jnk2 knockout cells (Jnk1(-/-) or Jnk2(-/-)) and cells expressing DNM JNK1 was observed. More importantly, incubation of active ERK2 or p38 kinase with H3 protein resulted in phosphorylation of H3 at serine 10 in vitro. These results suggest that ERK and p38 kinase are at least two important mediators of phosphorylation of H3 at serine 10.

Quantitative assessment of the tissue response to films of hyaluronan derivatives.

The aim of this study was to evaluate the in vivo response following implantation into a rat model of three innovative hyaluronan derivatives for clinical use: HYAFF 7, HYAFF 11 and HYAFF 11p75 (respectively, the 100% ethyl ester, 100% and 75% benzyl esters). The tissue reaction evoked by films of these new biomaterials implanted into the dorsolumbar musculature of rats was assessed quantitatively using a well established technique based upon an image analysis system. The number of inflammatory cells present and the patterns of cell distribution around the implant up to a distance of 642 microns were examined at different time periods after implantation. Since a well-delineated tissue-material interface was needed for this type of investigation, it was not possible to apply image analysis to sections once dissolution of the implanted materials had begun. Films of both the total esters, HYAFF 7 and HYAFF 11, were found to undergo a slow dissolution process and, after a month, films of these materials were still present at the site of implantation. Differences in response to the two materials were observed only during the first two weeks, particularly with respect to neutrophil distribution and total cellularity. HYAFF 7 was found to be more reactive, with higher numbers of neutrophils near the surface of the implant than HYAFF 11. Thereafter, the differences between the two materials were minimal and owing mainly to a faster dissolution of HYAFF 7 films. After 3 and 5 months, considerable degradation of films of both total esters had occurred. Significant quantities of material appeared inside numerous macrophages with an ED1-positive phenotype. Only a very thin layer of fibrous connective tissue, indicative of low reactivity, was found to surround the site of implantation, separating the dissolved material and the phagocytic cells from healthy muscular tissue. ED2-positive macrophages were primarily confined within the lining connective tissue. The partial benzyl ester, HYAFF 11p75, showed a different behaviour. In fact, evidence of film dissolution was already present a week after the implantation. After two weeks, the implanted films were completely dissolved and numerous ED1-positive macrophages phagocytosing the material were observed at the site of implantation. Therefore, in agreement with previous in vitro studies, which showed a greater susceptibility to degradation of hyaluronan derivatives with lower percentage of esterification, HYAFF 11p75 underwent resorption faster than the corresponding total ester.

Biodegradation of hyaluronic acid derivatives by hyaluronidase.

Hyaluronic acid (salt) (HA) has been chemically modified as a biomaterial for medical applications such as controlled drug release matrices, nerve guides and wound dressings. A series of HA derivatives, which include different ester types and different degrees of esterification, have been used to investigate the stability of these materials in testicular hyaluronidase. Gel permeation chromatography and capillary viscometer have been employed to determine the size of the molecules, the former used for the water insoluble derivatives that dissolve in dimethyl sulphoxide, the latter for the water soluble samples. The preliminary experimental results indicated that the molecular weight of fully esterified hyaluronic acid (both ethyl and benzyl esters) did not decrease after treatment in the enzyme for 7 and 14 days while the water soluble partially esterified HA were degraded by the enzyme producing a sharp reduction of viscosity within minutes. These observations tend to suggest that the carboxylic groups in the beta-glucoronic acid unit are the activation centre of this enzyme and the total blockage of these groups can restrict the cleavage of beta (1-->4) glycoside bonds by this enzyme.

Human neutrophil chemokinesis and polarization induced by hyaluronic acid derivatives.

Neutrophils and macrophages are known to undergo significant modifications in their morphology and basal metabolism in response to chemical factors, in particular changes in the shape, movement, phagocytic activity and degranulation. These phenomena often involve an increase in chemokinesis and cellular secretory activity, usually expressed in antimicrobial activity. Once activated, the cells can move quickly towards the source of the stimulus, where they produce and release great amounts of enzymes (e.g. proteases, hydrolases, lysozyme) and reactive oxygen metabolites (e.g. O2-., H2O2, OH.). This study has examined the ability of surfaces of selected biomaterials to influence neutrophil morphology and locomotion. The surface of two films derived from hyaluronic acid derivatives were compared with that of glass. The two hyaluronic acid derivatives, despite having a similar chemical structure, were shown to interact with human neutrophils in different ways. A hyaluronic acid ethyl ester stimulated the whole population of neutrophils to take up a non-spherical morphology (polarize) and to move with a velocity similar to that of N-formyl-methionine-leucine-phenylalanine-stimulated cells on a glass surface. In contrast, only 44% of the examined cells on the surface of hyaluronic acid benzyl ester were polarized and their mean speed was only slightly higher with respect to that found with non-stimulated cells on glass. Moreover, while on the benzyl ester and on glass a correlation between neutrophil circularity (i.e. the shape of the cell) and cell speed was found, the ethyl ester did not show any correlation.

Mechanisms of polymer degradation in implantable devices. I. Poly(caprolactone).

Poly(caprolactone) is a biodegradable aliphatic (poly(alpha-hydroxy acid), with important applications in the field of human therapy, due to its biocompatibility and bioresorbability. The degradation of poly(alpha-hydroxy acids) depends on chemical hydrolysis, but there is much interest in the precise mechanisms, including the role of free radicals, especially oxygen free radicals and their role in human disease. The hydrolytic degradation of poly(caprolactone) in aqueous environments was used as the control in a study of the effects of hydroxyl radicals in aqueous solutions. Different methods (GPC, DSC, SEM) were employed to investigate the mechanism of degradation of this semicrystalline physiologically absorbable polymer. The data indicate that hydroxyl radical is likely to be a major factor in the degradation of this polymer.

The mechanical and microscopic aspects of the deformation and fracture of a poly (ether urethane-urea) spun arterial prosthesis.

The mechanical properties of a microporous, electrostatically spun poly (ether urethane-urea), used in the construction of arterial prostheses, have been examined, with particular reference to anisotropic, crack initiation processes and preconditioning. The results demonstrate considerable anisotropy in relation to samples derived from circumferential and longitudinal directions of the tube wall structure related to the spinning process. There is also a considerable difference in crack initiation on inner and outer surface of the arterial wall, again related to the processing conditions. The results provide an important contribution to an understanding of structure-property relationships in microporous arterial prosthesis.