Three-dimensional scaffolds composed of biodegradable material

.. Three-dimensional scaffolds composed of biodegradable materials can provide platforms selleckchem Idelalisib for hepatocyte attachment (Fig. 1B). Fetal liver cells seeded in poly-L-lactic acid (PLLA) 3D macroporous scaffolds formed small clusters and showed higher levels of hepatic function, comparable with those of adult hepatocytes.21 Similarly, colonies of small hepatocytes (SHs), hepatic progenitor cells, placed on a collagen sponge with NPCs proliferated and expanded to form a hepatic organoid with highly differentiated functions.22 Hepatocytes seeded on PLLA and/or poly(D,L-lactide-co-glycolide) (PLGA) sponges were engrafted when they were implanted at a site associated with abundant vascular networks with appropriate surgical stimulation.

23,24 Both approaches for liver tissue reconstruction thus seems efficacious, since cell behavior can be controlled using materials with various structural and functional properties. However, these earlier studies using ECM or scaffold-based designs to engineer tissues face a major drawback, poor cell density. In native liver tissue, cell density is significantly higher, compared with other tissues, such as bone and cartilage. Accordingly, hepatocytes within native liver tightly interconnect to form layered structures, termed hepatic plates. Additionally, there is only a slight gap between hepatocytes and liver sinusoids, liver-specific microvessels, facilitating rapid exchange of macromolecules between plasma and hepatocytes. Thus, cell-sparse constructs engineered with those scaffolds often do not closely resemble the native liver architecture.

In contrast to earlier studies using ECM or biodegradable materials, scaffold-less cell-sheet engineering has been proposed for construction of 3D cell-dense liver tissue (Fig. 1C). For example, culture dishes, the surfaces of which were modified with a temperature-responsive polymer, have been used. Using such temperature-responsive culture surfaces, hepatocytes can be harvested as intact sheets and cell-dense thick tissues can be constructed by layering these cell sheets.25,26 However, a highly complex fabrication process is needed to covalently graft the temperature-responsive polymer onto dish surfaces27 and it also takes more than 30 min to harvest a cell sheet.28 Magnetite cationic liposomes have been also used to label cells and to form multilayered sheet architectures.

A magnetic field is then used to accumulate the magnetically-labeled cells onto ultralow attachment culture surfaces and form multilayered sheets.29 Entinostat Cells can be harvested readily as intact cell sheets by pipetting. However, when this method was applied to hepatocytes, the sheets were not sufficiently strong for recovery.30 Furthermore, because cells have to be harvested as an intact sheet in the two methods above, it is difficult to construct the complex 3D liver architectures that are made from smaller tissue units.

Cohesion is understood as a ��dynamic process that is reflected i

Cohesion is understood as a ��dynamic process that is reflected in part by the tendency of a group to stick together and remain united in the pursuit of enzyme inhibitor its instrumental objectives and/or for the satisfaction of member affective needs�� (Carron et al., 1998). The conceptual model of Carron et al. (1998) consists of four dimensions: Group integration-Task (GI-T), Group integration-Social (GI-S), Individual attraction to the group-Task (ATG-T), and Individual attraction to the group-Social (ATG-S). To create profiles according to this construct, this study divides cohesion into task and social dimensions because these dimensions have been shown to have more differences with respect to performance (Leo et al., 2010a). Carron et al.

��s (2002) meta-analysis demonstrated the importance of determining whether social or task aspects were related to performance. Their work identified studies that used only two dimensions and hence demonstrated problems with the presentation of the four factors of cohesion (Heuz�� et al., 2006; Leo et al., 2012). Thus, in this study, we differentiate between task cohesion, which reflects the degree to which group members work together to achieve common goals, and social cohesion, which reflects the degree to which team members empathise with each other and enjoy the group fellowship (Carron et al., 1998; Carron and Eys, 2012). These two dimensions are generated by environmental, personal, leadership and team factors that affect the perception of cohesion and produce individual and collective results, such as an influence on performance (Carron and Eys, 2012; Heuz�� et al.

, 2006; Leo et al., 2010; Paskevich et al., 1999). Many studies have assessed players�� and coaches�� opinions of team members�� efficacy (Bandura, 1997; Chase et al., 1997; Lent and L��pez, 2002). Three main types of sports-related team efficacy (Beauchamp, 2007) are noteworthy: perceived coach efficacy reflects a trainer��s confidence in a player��s abilities to perform given tasks (Beauchamp, 2007; Chase et al., 1997); perceived peer efficacy in sports represents players�� beliefs in their teammates�� abilities to accomplish a task successfully (Lent and L��pez, 2002); and collective efficacy is a group��s shared belief in its joint ability to organise and execute the courses of action required to produce certain achievement levels (Bandura, 1997).

Players form a perception of efficacy through these aspects, which lead to knowledge, affective and behavioural consequences, such as GSK-3 increasing or decreasing sport performance (Beauchamp, 2007; Watson et al., 2001). Numerous investigations have found a positive relationship between both psychological constructs��cohesion and perceived efficacy��and sport performance (Heuz�� et al., 2006; Kozub and McDonnell, 2000; Leo et al., 2010a; Paskevich et al., 1999; Ramzaninezhad et al., 2009; Spink, 1990; Myers et al., 2007).

6) Figure 6 B-line reproduction by hydration of gelatin samples

6). Figure 6. B-line reproduction by hydration of gelatin samples using different controlled water selleck chemicals llc volumes. One 10 ��L drop (A) and two drops (B) spaced about 1 cm apart. Materials and Methods Materials All materials were purchased from Sigma-Aldrich. A 5% w/v gelatin solution was prepared by dissolving gelatin (Type A) in deionized water dH2O stirring the solution for 1 h at 50��C. A batch cross-linking solution of glutaraldehyde (GTA) in water was prepared with a concentration of 0.1 M and used for sequential dilution. A 40% v/v ethanol: dH2O solution was used to rinse samples. Preparation of porous gelatin matrices Gelatin sponges were prepared to evaluate the porosity and mechanical properties as functions of cross-linking conditions as well as to recreate B-lines in an in vitro model.

In particular, the preparation method was divided into two steps. In the first step gelatin was cross-linked using GTA with different concentration (nominated GC); then, in order to obtain a porous matrix, a freeze-drying process was used as described by Lien et al.17 Briefly GTA was added to a 5% w/v gelatin solution to obtain a final volume of 1 mL and 0.1, 1 and 10 mM GC scaffolds were fabricated. The scaffolds were kept in a plastic tube (internal diameter 12 mm) at 25��C for 12 h, until the cross-link reaction had occurred. Two cooling steps were used to freeze the samples; the first step in a refrigerator at 4��C for 6 h and then the second step in a -20��C freezer over-night. Finally samples were freeze-dried (-50��C, 150 mBar) until all water content was removed.

Measurement of swelling ratio The water absorption capability of porous gelatin structures was determined by immersing freeze-dried samples in water for 1, 24 and 48 h. The swelling ratio was calculated according the following equation (Eq. 1): In which Wd is the air-dried scaffold weight and Ww is the weight of the wet scaffold.10 Porosity evaluation The porosity was evaluated by imbibition method and was assumed as the gelatin volume fraction in the swollen samples (). Through the water saturation, pore volume was evaluated by weighing swollen and dried samples. The gelatin volume fraction was calculated according to Equation 2:18,19 in which W0 is the dry weight of the sample, W is the weight of the swollen sample, ��w is the density of the water at RT (room temperature), and �� is the density of the dry gelatin sample.

Pore dimension was evaluated through histological analysis. Samples were embedded and fixed in Tissue-Tek O.C.T. before cryo-sectioning. Horizontal sections of 10 ��m thickness were obtained from the cylindrical scaffolds and then observed with an optical microscope (Olympus IX81, Olympus Italia, 4X objective). Measurement of mechanical properties Compressive mechanical tests were Anacetrapib performed using a twin column testing machine Zwick-Roell Z005 Instron (Zwick Testing Machines, Ltd.).

In fact, sulfated polysaccharides are commonly investigated for t

In fact, sulfated polysaccharides are commonly investigated for their biological properties, and the ones obtained from green algae are no exception. A summary of reported activities demonstrated in these polysaccharides is presented in Table 3. Table 3. Biological effects associated with sulfated polysaccharides from green algae For instance, these polysaccharides exhibit antioxidant effects, as was recently reported in several research works, describing sulfated polysaccharides with superoxide and hydroxyl radicals scavenging activity, reducing power and able to chelate metals.129-135 Antitumoral activity and antiproliferative effects have also been described and associated with these polysaccharides.

129,131,136 Another important features of these polysaccharides are their immunostimulating ability, similar to other algal polysaccharides,137-141 as well as their heparin-like character.105 Besides, these polysaccharides are largely studied for their antihyperlipidemic activities,130,142-145 or antiviral effects.111,131,146-148 Although common to the several sulfated polysaccharides extracted from green algae, the expression of those biological activities is dependent on different sugar composition, molecular weight and sulfate content,149 and thus, as abovementioned, on genus, species and ecological and environmental factors. Several studies stress this variability regarding heparin-like behavior according to the genus and species of the studied algae,115-117,129,131,150-152 but similar variability can be found on anticoagulant150-152 and antioxidant activities,133-135 as well as on antiproliferative effect, which was shown to be strongly related with the polysaccharide sulfate content.

129 Within this scenario, an attractive use and exploitation of green algae would take advantage of these biological properties and translate them into applications with pharmacological and medical relevance. However, among the three main divisions of macroalgae, green algae remain a rather underexploited biomass, particularly in areas where other algal origin polysaccharides have already proven their value. A striking example of commercial success is carrageenan (as discussed in the previous section). Alongside its biological activity and potential pharmaceutical use, green algae sulfated polysaccharides may also be used for biomedical applications, in areas as demanding as regenerative medicine.

In this particular arena, both their biological activities and their resemblance with glycosaminoglycans might position these polysaccharides in an advantageous point. In this regard, some important research work has already been performed related with polysaccharide modification, Brefeldin_A processing and biomaterial development, particularly using ulvan as a starting material. Described ulvan structures include nanofibers,153 membranes,154 particles,155 hydrogels156 and 3D porous structures.

It is contraindicated to breastfeed while a mother is undergoing

It is contraindicated to breastfeed while a mother is undergoing treatment with chemotherapeutic agents selleck chemicals Volasertib or while she is undergoing radiation therapy. Prognosis Although most studies have indicated equal prognosis of PABC (and breast cancer in women who were not pregnant) when matched for age and stage, a recent article showed poorer survival in those with PABC.17 Rodriguez and coworkers17 concluded that women with PABC presented with more advanced disease, larger tumors, and an increased percentage of hormone receptor-negative tumors. When controlled for stage and hormone receptor status, PABC carried a higher risk of death.17 It is unclear whether this is due to less aggressive therapy secondary to concern for fetal effects, a later stage at diagnosis due to the difficulties of diagnosing PABC, or physiologic changes in pregnancy that contribute to worse outcomes, or a combination of these factors.

More research is needed on PABC to find the optimal treatments. Pregnancy After Breast Cancer Treatment All premenopausal women diagnosed with breast cancer should be counseled regarding future fertility and contraceptive options. Regardless of fertility desires, it is imperative to discuss contraceptive options that are safe to use with a history of breast cancer. In general, hormonal therapies should be avoided; intrauterine devices or barrier methods are safe options. As most recurrences of breast cancer happen within 2 years of diagnosis, most people recommend waiting at least 2 years from remission prior to conceiving.6 Chemotherapy agents can also cause infertility.

If a patient desires future fertility, referral to a fertility specialist to discuss egg or embryo freezing would be prudent. If patients do desire to preserve fertility, options include ovarian or embryo cryopreservation. Embryo cryopreservation can be performed with natural cycle in vitro fertilization to avoid use of ovulation induction. Tamoxifen and letrozole have emerged as possible options for ovulation induction in patients with breast cancer.18 Ovarian cryopreservation can be an option for patients without a current partner who desire to preserve fertility; however, current studies have not shown great success. The risk of infertility with chemotherapy depends on the patient��s age at initiation of chemotherapy and the chemotherapeutic agents used.

Each course of chemotherapy will result in a loss of ovarian reserve, causing menopause to occur earlier.18 Depending on the patient��s age and baseline ovarian reserve, chemotherapeutic agents will affect each patient��s fertility differently. Alkylating agents are the most likely cytotoxic drug to cause amenorrhea.18 The risk is somewhat lower Batimastat with anthracyclines or antimetabolites.18 Tamoxifen itself does not cause infertility, but it is recommended that a woman not conceive while on tamoxifen due to its teratogenic effects to the fetus.

, 2005; Chiu et al , 2003) Tillin and Bishop (2009) suggested th

, 2005; Chiu et al., 2003). Tillin and Bishop (2009) suggested that PAP is able to potentially increase mechanical power as well as explosive activity and hence, performance and/or the training stimulus of that activity. To our knowledge, the effect of dynamic stretching on performance of a multiarticular sport skill, such as the soccer kick, has not been thoroughly Paclitaxel human endothelial cells investigated. The instep kick is one of the most characteristic skills of a soccer player (Amiri-Khorasani et al., 2011a,b, 2010a,b, 2009; Kellis and Katis, 2007; Kellis et al., 2006). Soccer kicks performed via a stretch-shortening cycle of the knee extensors display higher ball velocity compared to soccer kicks involving only concentric actions (Bober et al., 1987).

For this reason, research studies have focused on the role of stretch-shortening cycle of the knee extensors for a successful kick. Particularly, a soccer kick is accompanied by a stretch of the knee extensor musculature during backswing followed by instantaneous shortening during forward shank movement. Each phase, however, is accompanied by different behavior of the quadriceps components. During backswing, the thigh accelerates via a high activation of rectus femoris (Dorge et al., 1999; Sorensen et al., 1996). Forward swing is characterized by a high activation of vastus lateralis which then decreases when the shank starts to decelerate (Dorge et al., 1999; Sorensen et al., 1996). It seems, therefore, that evaluation of only one component of the quadriceps muscle cannot fully describe the role of the whole muscle group during the soccer kick.

In previous experiments, Amiri-Khorasani et al. (2010a) reported that maximum ball speed and vastus medialis electromyographic (EMG) activation during soccer instep kicking increased more after dynamic rather than static stretching. However, in this study the experimental groupconsisted only of six subjects and EMG activation of only vastus medialis was analyzed. It is not clear whether this reflects the whole quadriceps muscle or the effects of stretching are muscle-dependent. Since some of the quadriceps are mono-articular (vastii muscles) while others are bi-articular (rectus femoris) then it would be interesting to examine whether dynamic stretching affects activation of only some parts of the quadriceps and whether this differs from static stretching effects.

Therefore, the purpose of the present study was to investigate the acute effects of dynamic and static stretching on vastus medialis (VM), Carfilzomib vastus lateralis (VL) and rectus femoris (RF) activation during maximal instep soccer kicks. We hypothesized that dynamic stretching would cause a higher increase in quadriceps muscle activation compared to that observed after static stretching. Material and Methods Participants Twelve male college soccer players (mean �� SD: body height: 180.08 �� 4.16 cm; body mass: 78.16 �� 4.44 kg; age: 19.16 �� 0.