Application of platelet-rich plasma with stem cells in bone and periodontal tissue engineering

Presently, there is a high paucity of bone grafts in the United States and worldwide. Regenerating bone is of prime concern due to the current demand of bone grafts and the increasing number of diseases causing bone loss. Autogenous bone is the present gold standard of bone regeneration. However, disadvantages like donor site morbidity and its decreased availability limit its use. Even allografts and synthetic grafting materials have their own limitations. As certain specific stem cells can be directed to differentiate into an osteoblastic lineage in the presence of growth factors(GFs), it makes stem cells the ideal agents for bone regeneration.Furthermore, platelet-rich plasma(PRP), which can be easily isolated from whole blood, is often used for bone regeneration, wound healing and bone defect repair. When stem cells are combined with PRP in the presence of GFs, they are able to promote osteogenesis. This review provides in-depth knowledge regarding the use of stem cells and PRP in vitro, in vivo and their application in clinical studies in the future.

A Time to Event Analysis of Adverse Drug Reactions Due to Tenofovir, Zidovudine and Stavudine in a Cohort of Patients Receiving Antiretroviral Treatment at an Outpatient Clinic in Zimbabwe

Background: Achieving the long terms goals of antiretroviral treatment (ART) requires a careful approach during treatment initiation that takes into account patient’s psychosocial state, availability and accessibility of treatment combinations, and adherence support. Adverse drug reactions that occur during the initial phases have a bearing on treatment outcomes and thus need to be monitored and treated. Objective: This study was done to assess length of time (survival time) it took for clinically significant adverse drug reactions to occur in patients taking Nucleoside Reverse Transcriptase Inhibitors (N(t)RTI) available for treatment of Human Immunodeficiency Virus (HIV) infection in Zimbabwe. Methods: A retrospective cohort of patient data collected from January 2009 to December 2012 was extracted from an Electronic Health Record database. Data from patients who were initiated on antiretroviral (ARV) drug regimens containing N(t)RTI drugs were analysed for survival time. A sample of 205 patient files was extracted for the time period for survival analysis using adverse drug reactions due to N(t)RTI drugs. Results: After data extraction, a total of 205 patient records were used in determining the time to event analysis of ADR’s in the cohort. The age range for the patients included in the study was 9 - 76 with a mean of 41 years (s.d = 14.8). Patients initiated on stavudine had a lower survival time before a clinically significant ADR compared to tenofovir (-365 days, p-value < 0.0005). Patients on zidovudine also had a less time before a significant reaction compared to those on tenofovir (-230 days;p-value = 0.008). Patients on zidovudine fared better compared to those on stavudine (-134 days;p-value < 0.0005). The mean survival time was highest for tenofovir (618 days), followed by zidovudine (388 days), and then stavudine (254 days).Conclusion: Patients on tenofovir have a longer survival time before a clinically significant adverse reaction. Treatment programmes need to continue commencing patients on tenofovir containing regimens as patients can be maintained for longer periods on this regimen.

Onecut transcription factors in retinal development and maintenance

The retina and its development： The retina is an essential part of the visual system. A myriad of eye diseases are characterized by retinal degeneration, caused by either genetic or environmental factors. This underscores the importance of studying the genetic and molecular mechanisms that regulate the generation and maintenance of neurons in the mammalian retina. Our recent studies demonstrate that two related transcription factors Onecutl （Ocl） and Onecut2 （0c2） regulate multiple cell fates in the mouse retina, and their absence results in progressive retinal neurodegeneration （Wu et al., 2012, 2013; Sapkota et al., 2014）.

Fast photocurable thiol-ene elastomers with tunable biodegradability,mechanical and surface properties enhance myoblast differentiation and contractile function

Biodegradable elastomers are important emerging biomaterials for biomedical applications,particularly in the area of soft-tissue engineering in which scaffolds need to match the physicochemical properties of native tissues.Here,we report novel fast photocurable elastomers with readily tunable mechanical properties,surface wettability,and degradability.These elastomers are prepared by a 5-min UV-irradiation of thiol-ene reaction systems of glycerol tripentenoate(GTP;a triene)or the combination of GTP and 4-pentenyl 4-pentenoate(PP;a diene)with a carefully chosen series of di-or tri-thiols.In the subsequent application study,these elastomers were found to be capable of overcoming delamination of myotubes,a technical bottleneck limiting the in vitro growth of mature functional myofibers.The glycerol-based elastomers supported the proliferation of mouse and human myoblasts,as well as myogenic differentiation into contractile myotubes.More notably,while beating mouse myotubes detached from conventional tissue culture plates,they remain adherent on the elastomer surface.The results suggest that these elastomers as novel biomaterials may provide a promising platform for engineering functional soft tissues with potential applications in regenerative medicine or pharmacological testing.

Nuclear Factor I/A Controls A-fiber Nociceptor Development

Noxious mechanical information is transmitted through molecularly distinct nociceptors,with pinprickevoked sharp sensitivity via A-fiber nociceptors marked by developmental expression of the neuropeptide Y receptor 2(Npy2 r)and von Frey filament-evoked punctate pressure information via unmyelinated C fiber nociceptors marked by MrgprD.However,the molecular programs controlling their development are only beginning to be understood.Here we demonstrate that Npy2 r-expressing sensory neurons are in fact divided into two groups,based on transient or persistent Npy2 r expression.Npy2 r-transient neurons are myelinated,likely including A-fiber nociceptors,whereas Npy2 r-persistent ones belong to unmyelinated pruriceptors that co-express Nppb.We then showed that the transcription factors NFIA and Runx1 are necessary for the development of Npy2 r-transient A-fiber nociceptors and MrgprD^+C-fiber nociceptors,respectively.Behaviorally,mice with conditional knockout of Nfia,but not Runx1 showed a marked attenuation of pinprick-evoked nocifensive responses.Our studies therefore identify a transcription factor controlling the development of myelinated nociceptors.