Laparoscopic versus hybrid approach for treatment of incisional ventral hernia: a 5-10-year follow-up of the randomized controlled multicenter study.

PURPOSE: In this long-term follow-up of a prospective, randomized, and multicenter study, we compare the results of a group receiving laparoscopic incisional ventral hernia repair using intraperitoneal onlay mesh (LG) to a group receiving a hybrid hernia repair where open closure of fascial defect was added to intraperitoneal mesh placement (HG). METHODS: Originally, 193 patients with 2-7 cm incisional hernias were randomly assigned to either the LG or HG during the 30-month recruitment period in 2012 to 2015. Long-term follow-up was conducted 5-10 years after surgery to evaluate hernia recurrence rate and quality of life (QoL). RESULTS: In all, 65 patients in the LG and 60 in the HG completed the long-term follow-up with a median follow-up period of 87 months. Recurrent hernia was detected in 11 of 65 patients (16.9%) in the LG and 10 of 60 patients (16.7%) in the HG (p > 0.9). Kaplan-Meier analysis demonstrated a recurrence rate approaching 20% in both groups, with similar curves. Three patients in the LG (4.6% and five patients in the HG (8.1%) had undergone re-operation due to recurrence (p = 0.48). There was no difference in patient-reported QoL measured using the SF-36 questionnaire. Mean pain scores were similar between groups, mean numeric rating scale (NRS) 0 to 10 being 1.1 in the LG and 0.7 in the HG (p = 0.43). CONCLUSION: Fascial closure did not reduce hernia recurrence rate in this study population, even though it has been shown to be beneficial and recommended in surgery guidelines. In the long term, recurrence rate for both groups is similar.

Reduced Number of Pediatric Orthopedic Trauma Requiring Operative Treatment during COVID-19 Restrictions: A Nationwide Cohort Study.

BACKGROUND AND AIMS: The coronavirus outbreak significantly changed the need of healthcare services. We hypothesized that the COVID-19 pandemic decreased the frequency of pediatric fracture operations. We also hypothesized that the frequency of emergency pediatric surgical operations decreased as well, as a result of patient-related reasons, such as neglecting or underestimating the symptoms, to avoid hospital admission. MATERIALS AND METHODS: Nationwide data were individually collected and analyzed in all five tertiary pediatric surgical/trauma centers in Finland. Operations related to fractures, appendicitis, and acute scrotum in children aged above 16 years between March 1 and May 31 from 2017 to 2020 were identified. The monthly frequencies of operations and type of traumas were compared between prepandemic 3 years and 2020. RESULTS: Altogether, 1755 patients were identified in five tertiary hospitals who had an emergency operation during the investigation period. There was a significant decrease (31%, p = 0.03) in trauma operations. It was mostly due to reduction in lower limb trauma operations (32%, p = 0.006). Daycare, school, and organized sports-related injuries decreased significantly during the pandemic. These reductions were observed in March and in April. The frequencies of appendectomies and scrotal explorations remained constant. CONCLUSION: According to the postulation, a great decrease in the need of trauma operations was observed during the peak of COVID-19 pandemic. In the future, in case similar public restrictions are ordered, the spared resources could be deployed to other clinical areas. However, the need of pediatric surgical emergencies held stable during the COVID-19 restrictions.

Selection of resistance by antimicrobial coatings in the healthcare setting.

Antimicrobial touch surfaces have been introduced in healthcare settings with the aim of supporting existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which may drive the evolution and spread of antimicrobial resistance. This review highlights studies that indicate risks associated with resistance on antimicrobial surfaces by different processes, including evolution by de-novo mutation and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed on to antimicrobial surfaces. The review focuses on antimicrobial surfaces made of copper, silver and antimicrobial peptides because of the practical application of copper and silver, and the promising characteristics of antimicrobial peptides. The available data point to a potential for resistance selection and a subsequent increase in resistant strains via cross-resistance and co-resistance conferred by metal and antibiotic resistance traits. However, translational studies describing the development of resistance to antimicrobial touch surfaces in healthcare-related environments are rare, and will be needed to assess whether and how antimicrobial surfaces lead to resistance selection in these settings. Such studies will need to consider numerous variables, including the antimicrobial concentrations present in coatings, the occurrence of biofilms on surfaces, and the humidity relevant to dry-surface environments. On-site tests on the efficacy of antimicrobial coatings should routinely evaluate the risk of selection associated with their use.

Specialized cleaning associated with antimicrobial coatings for reduction of hospital-acquired infection: opinion of the COST Action Network AMiCI (CA15114).

Recognized issues with poor hand hygiene compliance among healthcare workers and reports of recontamination of previously chemically disinfected surfaces through hand contact emphasize the need for novel hygiene methods in addition to those currently available. One such approach involves antimicrobial (nano) coatings (AMCs), whereby integrated active ingredients are responsible for elimination of micro-organisms that come into contact with treated surfaces. While widely studied under laboratory conditions with promising results, studies under real-life healthcare conditions are scarce. The views of 75 contributors from 30 European countries were collated regarding specialized cleaning associated with AMCs for reduction of healthcare-associated infection. There was unanimous agreement that generation of scientific guidelines for cleaning of AMCs, using traditional or new processes, is needed. Specific topics included: understanding mechanisms of action of cleaning materials and their physical interactions with conventional coatings and AMCs; that assessments mimic the life cycle of coatings to determine the impact of repetitive cleaning and other aspects of ageing (e.g. exposure to sunlight); determining concentrations of AMC-derived biocides in effluents; and development of effective de-activation and sterilization treatments for cleaning effluents. Further, the consensus opinion was that, prior to widespread implementation of AMCs, there is a need for clarification of the varying responsibilities of involved clinical, healthcare management, cleaning services and environmental safety stakeholders.

Bacterial community changes in copper and PEX drinking water pipeline biofilms under extra disinfection and magnetic water treatment.

AIMS: To study the stability of biofilms and water quality in pilot scale drinking water copper and PEX pipes in changing conditions (extra disinfection, magnetic water treatment, MWT). METHODS AND RESULTS: Next-generation sequencing (NGS) of 16S ribosomal RNA genes (rDNA) to describe total bacterial community and ribosomal RNA (rRNA) to describe active bacterial members in addition to traditional microbiological methods were applied. Biofilms from control copper and PEX pipes shared same most abundant bacteria (Methylobacterium spp., Sphingomonas spp., Zymomonas spp.) and average species diversities (Shannon 3·8-4·2) in rDNA and rRNA libraries, whereas few of the taxa differed by their abundance such as lower total Mycobacterium spp. occurrence in copper (<0·02%) to PEX (<0·2%) pipes. Extra disinfection (total chlorine increase from c. 0·5 to 1 mg l-1 ) affected total and active population in biofilms seen as decrease in many bacterial species and diversity (Shannon 2·7, P < 0·01, rRNA) and increase in Sphingomonas spp. as compared to control samples. Furthermore, extra-disinfected copper and PEX samples formed separate clusters in unweighted non-metric multidimensional scaling plot (rRNA) similarly to MWT-treated biofilms of copper (but not PEX) pipes that instead showed higher species diversity (Shannon 4·8, P < 0·05 interaction). CONCLUSIONS: Minor chlorine dose addition increased selection pressure and many species were sensitive to chlorination. Pipe material seemed to affect mycobacteria occurrence, and bacterial communities with MWT in copper but not in PEX pipes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study using rRNA showed that chlorination affects especially active fraction of bacterial communities. Copper and PEX differed by the occurrence of some bacterial members despite similar community profiles.

Spinal canal dimensions affect outcome of adolescent disc herniation.

PURPOSE: Small spinal canal dimensions play a role in symptomatic adult disc herniation, but its role in adolescent disc herniation has not been investigated with MRI. The goal of this study was to examine retrospectively if there is a correlation with dimensions of osseous spinal canal and need of discectomy in an adolescent population suffering from disc herniation. METHODS: A retrospective review of child and adolescent patients who were treated in our institution for back or back--related leg pain was conducted. Patients were divided in three groups; group 1: lumbar disc herniation requiring operative treatment; group 2: lumbar disc herniation treated with observation; and group 3: back pain and no disc herniation on MRI. MRI images and radiographs were studied for spinal canal dimensions and compared between groups. RESULTS: The discectomy group presented considerably smaller spinal canal dimensions measured from the MRI images than the two other groups. CONCLUSION: Adolescent patients requiring operative treatment for symptomatic disc herniation have smaller osseous spinal canals than patients who are managed non-operatively.

Copper as an antibacterial material in different facilities.

The present study was performed in real life settings in different facilities (hospital, kindergarten, retirement home, office building) with copper and copper alloy touch surface products (floor drain lids, toilet flush buttons, door handles, light switches, closet touch surfaces, corridor hand rails, front door handles and toilet support rails) in parallel to reference products. Pure copper surfaces supported lower total bacterial counts (16 ± 45 vs 105 ± 430 CFU cm-2 , n = 214, P < 0·001) and a lower occurrence of Staphylococcus aureus (2·6 vs 14%, n = 157, P < 0·01) and Gram-negatives (21 vs 34%, n = 214, P < 0·05) respectively than did reference surfaces, whereas the occurrence of enterococci (15%, n = 214, P > 0·05) was similar. The studied products could be assigned to three categories according to their bacterial loads as follows (P < 0·001): floor drain lids (300 ± 730 CFU cm-2 , n = 32), small area touch surfaces (8·0 ± 7·1 to 62 ± 160 CFU cm-2 , n = 90) and large area touch surfaces (1·1 ± 1·1 to 1·7 ± 2·4 CFU cm-2 , n = 92). In conclusion, copper touch surface products can function as antibacterial materials to reduce the bacterial load, especially on frequently touched small surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The efficiency of copper as an antimicrobial material has been noted in laboratory studies and in the hospital environment. The present study further shows that copper exerted an antibacterial effect in different facilities, i.e. in a hospital, a kindergarten, an office building and in a retirement home for the elderly. The study suggests that copper has potential use as an antibacterial material and therefore might serve as a means to lower the incidence of transmission of infectious agents from inanimate surfaces in different facilities, with everyday functions.

Anti-tumour activity of oncolytic Western Reserve vaccinia viruses in canine tumour cell lines, xenografts, and fresh tumour biopsies.

Cancer is one of the most common reasons for death in dogs. One promising approach is oncolytic virotherapy. We assessed the oncolytic effect of genetically modified vaccinia viruses in canine cancer cells, in freshly excised tumour biopsies, and in mice harbouring canine tumour xenografts. Tumour transduction efficacy was assessed using virus expressing luciferase or fluorescent marker genes and oncolysis was quantified by a colorimetric cell viability assay. Oncolytic efficacy in vivo was evaluated in a nude mouse xenograft model. Vaccinia virus was shown to infect most tested canine cancer cell lines and primary surgical tumour tissues. Virus infection significantly reduced tumour growth in the xenograft model. Oncolytic vaccinia virus has antitumour effects against canine cancer cells and experimental tumours and is able to replicate in freshly excised patient tumour tissue. Our results suggest that oncolytic vaccinia virus may offer an effective treatment option for otherwise incurable canine tumours.

CD40 ligand and tdTomato-armed vaccinia virus for induction of antitumor immune response and tumor imaging.

Oncolytic vaccinia virus is an attractive platform for immunotherapy. Oncolysis releases tumor antigens and provides co-stimulatory danger signals. However, arming the virus can improve efficacy further. CD40 ligand (CD40L, CD154) can induce apoptosis of tumor cells and it also triggers several immune mechanisms. One of these is a T-helper type 1 (Th1) response that leads to activation of cytotoxic T-cells and reduction of immune suppression. Therefore, we constructed an oncolytic vaccinia virus expressing hCD40L (vvdd-hCD40L-tdTomato), which in addition features a cDNA expressing the tdTomato fluorochrome for detection of virus, potentially important for biosafety evaluation. We show effective expression of functional CD40L both in vitro and in vivo. In a xenograft model of bladder carcinoma sensitive to CD40L treatment, we show that growth of tumors was significantly inhibited by the oncolysis and apoptosis following both intravenous and intratumoral administration. In a CD40-negative model, CD40L expression did not add potency to vaccinia oncolysis. Tumors treated with vvdd-mCD40L-tdtomato showed enhanced efficacy in a syngenic mouse model and induced recruitment of antigen-presenting cells and lymphocytes at the tumor site. In summary, oncolytic vaccinia virus coding for CD40L mediates multiple antitumor effects including oncolysis, apoptosis and induction of Th1 type T-cell responses.

Oral rinse MMP-8 point-of-care immuno test identifies patients with strong periodontal inflammatory burden.

OBJECTIVE: To determine whether oral rinse matrix metalloproteinase (MMP)-8 levels, measured by three different methods, tissue inhibitor of matrix metalloprotease-1 (TIMP-1) levels and elastase activity differentiate subjects with different periodontal condition; and second, to find out if MMP-8 levels were comparable among the methods used. METHODS: MMP-8 levels were analysed with an immunofluorometric method (IFMA), dentoELISA and commercial ELISA. Also TIMP-1 levels and elastase activity were measured. For statistical analysis 214 study subjects were categorized into four groups, specified by the presence and number of moderate (4-5mm) and deep (≥6mm) periodontal pockets, and bleeding on probing percentage. RESULTS: MMP-8 levels especially measured by dentoELISA and adjusted to the number of teeth per subject differentiated the study group with strong periodontal inflammatory burden from groups with lower levels. This was also verified with receiver operating characteristic (ROC) analysis. Elastase activity associated with higher IFMA and dentoELISA MMP-8 levels. IFMA MMP-8/TIMP and dentoELISA MMP-8/TIMP-1 tended to be higher with the increasing level of periodontal inflammatory burden. TIMP-1 levels decreased with increasing age. CONCLUSIONS: Oral rinse MMP-8 together with TIMP-1 analysis may have potential in complementary periodontal diagnostics. dentoELISA can be applied in quantitative oral rinse chair side biomarker diagnostics.

Changing the adenovirus fiber for retaining gene delivery efficacy in the presence of neutralizing antibodies.

Prior infection has primed most adult humans for a rapid neutralizing antibody (NAb) response when re-exposed to adenovirus. NAb induction can severely limit the efficacy of systemic re-administration of adenoviral gene therapy. We hypothesized that changing the fiber knob could overcome NAb. Immune-competent mice were exposed to serotype 5 adenovirus (Ad5)(GL), Ad5/3luc1, Ad5lucRGD or Ad5pK7(GL). Mice immunized with Ad5(GL) featured reduced intravenous Ad5(GL) gene transfer to most organs, including the liver, lung and spleen. Ad5(GL) gene transfer was affected much less by exposure to capsid-modified viruses. Anti-Ad5(GL) NAb blocked intravenous Ad5(GL) gene transfer to orthotopic lung cancer xenografts, whereas capsid-modified viruses were not affected. When gene transfer to fresh cancer and normal lung explants was analyzed, we found that capsid-modified viruses allowed effective gene delivery to tumors in the presence of anti-Ad5(GL) NAb, whereas Ad5(GL) was blocked. In contrast, crossblocking by NAbs induced by different viruses affected gene delivery to normal human lung explants, suggesting the importance of non-fiber-knob-mediated infection mechanisms. We conclude that changing the adenovirus fiber knob is sufficient to allow a relative degree of escape from preexisting NAb. If confirmed in trials, this approach might improve the efficacy of re-administration of adenoviral gene therapy to humans.

The effect of chemical inhibition of matrix metalloproteinases on the size of experimentally induced apical periodontitis.

AIM: To determine the effect of matrix metalloproteinase (MMP) inhibition on periapical lesion formation in a rat model. METHODOLOGY: The pulp chambers of mandibular fist molars of adult SD rats were exposed to be infected by oral microbes. The experimental group was fed 20 mg kg(-1) MMP-inhibitor chemically modified tetracycline-3 (CMT-3) daily in an oral gavage and the controls were fed the vehicle. After 2 and 4 weeks, the mandibles (n = 10 in both groups at both times) were radiographed, decalcified and subjected to histological analysis. Extension of necrosis in first molar distal root canals was measured from the histological sections, and periapical lesion sizes in the same roots were determined from radiographs and histological sections. Mann-Whitney U-test was used for the statistical analysis. RESULTS: There was a statistically significant difference in the extension of necrosis in root canals between 2 and 4 weeks in the control group (P < 0.05), but not with MMP inhibition. Radiographically, MMP inhibition increased the periapical lesion size by 70% and 34% after 2 and 4 weeks respectively (P < 0.05 in after 2 weeks). In histological measurements, lesion size increased with MMP inhibition by 26% and 8% after 2 and 4 weeks respectively. CONCLUSIONS: MMP inhibition affects pulpal and periapical inflammation, increasing the rate of spreading of necrosis in root canals and the rate of periapical lesion formation.

[AIDS prevention in austrian schools]. / Aids-Prävention an österreichischen Schulen. Aufklärungsprojekte zu HIV und Aids in Wien.

Prevention campaigns and new antiretroviral therapies caused a decline in HIV-infections as well as mortality from HIV/AIDS in industrialised countries. Despite this development AIDS is one of the ten mean causes of death worldwide, with 3,1 million deaths in 2002. Hence there is an urgent need for prevention and information campaigns, which ideally should start in early childhood or at school age. It is well known that preventive strategies start at a time when the risk or the possibility of a risky behaviour does not yet exist. A WHO-report in 1993 showed, that sex education often comes too late, as sexual activity of adolescents is already on its way. Persons who are already sexually active can be influenced to have fewer sexual partners and to increase safer sex methods. There is no evidence for causing a higher risk by sex education of adolescents. In Austrian schools numerous experts and organisations cooperate in the sphere of sex education and STD-prevention. School children in Vienna are confronted with this topic by the schools they attend according to the Sex Education-Act of 1970 on a voluntary basis. Various examples of effective teaching models prove intensive efforts and successful interdisciplinary cooperation. This study analyses common risk-reduction-methods and describes the Austrian way of HIV/AIDS/STD prevention in school children, although there is no obligation for sex education in schools, according to the School Teaching-Act of 1986, which leads to better knowledge and subsequent risk behaviour of adolescents in the same geographical area.

Accelerated up-regulation of L-Sox5, Sox6, and Sox9 by BMP-2 gene transfer during murine fracture healing.

Fracture repair is the best-characterized situation in which activation of chondrogenesis takes place in an adult organism. To better understand the mechanisms that regulate chondrogenic differentiation of mesenchymal progenitor cells during fracture repair, we have investigated the participation of transcription factors L-Sox5, Sox6, and Sox9 in this process. Marked up-regulation of L-Sox5 and Sox9 messenger RNA (mRNA) and smaller changes in Sox6 mRNA levels were observed in RNAse protection assays during early stages of callus formation, followed by up-regulation of type II collagen production. During cartilage expansion, the colocalization of L-Sox5, Sox6, and Sox9 by immunohistochemistry and type II collagen transcripts by in situ hybridization confirmed a close relationship of these transcription factors with the chondrocyte phenotype and cartilage production. On chondrocyte hypertrophy, production of L-Sox5, Sox9 and type II collagen were down-regulated markedly and that of type X collagen was up-regulated. Finally, using adenovirus mediated bone morphogenetic protein 2 (BMP-2) gene transfer into fracture site we showed accelerated up-regulation of the genes for all three Sox proteins and type II collagen in fractures treated with BMP-2 when compared with control fractures. These data suggest that L-Sox5, Sox6, and Sox9 are involved in the activation and maintenance of chondrogenesis during fracture healing and that enhancement of chondrogenesis by BMP-2 is mediated via an L-Sox5/Sox6/Sox9-dependent pathway.

Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human chondrosarcomas.

The aim of the present study was to characterise the ability of malignant chondrosarcomas to invade normal bone by analysing their production of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). For this purpose 12 chondrosarcomas were investigated for the expression of mRNAs for several MMPs and all 4 TIMPs by Northern hybridisation, and for immunohistochemical localisation of the proteins. A characteristic finding of these analyses was increased expression of MMP-13, MMP-14 and TIMP-2 mRNAs in chondrosarcomas when compared with nonmalignant control samples. Individual chondrosarcomas also exhibited elevated levels of MMP-1, MMP-7 and MMP-9 mRNAs. The results of Northern hybridisations were supported by immunohistochemical stainings of the corresponding tumour areas for MMP-2, MMP-14 and TIMP-2, further suggesting that these may have prognostic value for determining whether individual chondrosarcomas are locally aggressive or have a probability of recurrence. Another finding of the present study was a marked heterogeneity in histologic appearance and gene expression of the chondrosarcomas, emphasising the importance of analysing several areas of these tumours to get representative results. These findings suggest that analysis of MMPs could be a useful diagnostic indicator in patients with cartilaginous tumours and could help in differentiating between a low-grade malignant chondrosarcoma and a benign growing enchondroma.

Vitamin D and prostate cancer.

Our recent epidemiological study (Ahonen et al., Cancer Causes Control 11(2000) (847-852)) suggests that vitamin D deficiency may increase the risk of initiation and progression of prostate cancer. The nested case-control study was based on a 13-year follow-up of about 19000 middle-aged men free of clinically verified prostate cancer. More than one-half of the serum samples had 25OH-vitamin D (25-VD) levels below 50 nmol/l, suggesting VD deficiency. Prostate cancer risk was highest among the group of younger men (40-51 years) with low serum 25-VD, whereas low serum 25-VD appeared not to increase the risk of prostate cancer in older men (>51 years). This suggests that VD has a protective role against prostate cancer only before the andropause, when serum androgen concentrations are higher. The lowest 25-VD concentrations in the younger men were associated with more aggressive prostate cancer. Furthermore, the high 25-VD levels delayed the appearance of clinically verified prostate cancer by 1.8 years. Since these results suggest that vitamin D has a protective role against prostate cancer, we tried to determine whether full spectrum lighting (FSL) during working hours could increase serum 25-VD concentrations. After 1-month exposure, there was no significant increase in the serum 25-VD level, although there was a bias towards slightly increasing values in the test group as opposed to decreasing values in controls. There was no significant change in the skin urocanic acid production. The possibility to use FSL in cancer prevention is discussed. In order to clarify the mechanism of VD action on cell proliferation and differentiation, we performed studies with the rat and human prostates as well prostate cancer cell lines. It is possible that 25-VD may have a direct role in the host anticancer defence activity, but the metabolism of vitamin D in the prostate may also play an important role in its action. We raised antibodies against human 1alpha-hydroxylase and 24-hydroxylase. Our preliminary results suggest that vitamin D is actively metabolised in the prostate. Vitamin D appears to upregulate androgen receptor expression, whereas androgens seem to upregulate vitamin D receptor (VDR). This may at least partially explain the androgen dependence of VD action. VD alone or administered with androgen causes a suppression of epithelial cell proliferation. VD can activate mitogen-activated kinases, erk-1 and erk-2, within minutes and p38 within hours. Also, auto/paracrine regulation might be involved, since keratinocyte growth factor (mRNA and protein) was clearly induced by VD. Based on these studies, a putative model for VD action on cell proliferation and differentiation is presented.

A metaphyseal defect model of the femur for studies of murine bone healing.

A bone defect model was developed in the distal metaphysis of the femur for studies on bone healing in the mouse. The circular defect involving 20% of the bone circumference resulted in a 34% reduction in the bending moment compared to intact bone. The healing process was followed using histomorphometry, peripheral quantitative computed tomography (pQCT), biomechanical testing, and molecular biological analyses. Histologically, healing of the defect was characterized by filling of the medullary cavity with trabecular new bone during the first week of healing, and by closing of the cortical window by 6 weeks. Small areas of periosteal chondrogenesis were frequently observed during defect healing. In pQCT, bone mineral content (BMC) of the defect area approached that of intact control bone already by 3 weeks, reflecting the production of trabecular bone. Similarly, the bending strength and stiffness of the healing femur reached the level of intact control femur already at 3 weeks. Bone formation and remodeling was followed by Northern analyses, which demonstrated elevated mRNA levels for bone components (type I collagen and osteocalcin), and for osteoclastic enzymes (cathepsin K, matrix metalloproteinase-9, and tartrate-resistant acid phosphatase) throughout the healing period. Finally, the applicability of the defect model for gene therapy experiments was tested using adenovirus-mediated transfer of the LacZ reporter gene. Both histochemistry and mRNA analyses demonstrated that the gene was expressed in the repair tissue with the highest expression during the first week of healing. The present model thus provides a standardized environment for studies on induction and remodeling of trabecular new bone in normal and genetically engineered mice.

Induction of periosteal callus formation by bone morphogenetic protein-2 employing adenovirus-mediated gene delivery.

Although the chondrogenic response of periosteum is well established in healing fractures, the mechanisms mediating the proliferation and differentiation of periosteal chondroprogenitor cells are poorly understood. In the present study we demonstrate that bone morphogenetic protein-2 (BMP-2), introduced by adenovirus-mediated gene transfer, alone is capable of inducing callus formation at the site of periosteal injection. Both immunohistochemistry and Northern analysis demonstrated activation of type II collagen production between days 4 and 7 after the injection, followed by activation of type X collagen expression. The activation of chondrogenesis was associated with increased expression of L-Sox5 and Sox9, suggesting that the BMP-2 effect is mediated via Sox proteins. This capacity of adenovirus-mediated overproduction of BMP-2 to induce chondrogenesis (and subsequent endochondral ossification) should be useful for tissue engineering of cartilage and bone.

MAPK/ERK overrides the apoptotic signaling from Fas, TNF, and TRAIL receptors.

The tumor necrosis factor (TNF), Fas, and TNF-related apoptosis-inducing ligand (TRAIL) receptors (R) are highly specific physiological mediators of apoptotic signaling. We observed earlier that a number of FasR-insensitive cell lines could redirect the proapoptotic signal to an anti-apoptotic ERK1/2 signal resulting in inhibition of caspase activation. Here we determine that similar mechanisms are operational in regulating the apoptotic signaling of other death receptors. Activation of the FasR, TNF-R1, and TRAIL-R, respectively, rapidly induced subsequent ERK1/2 activation, an event independent from caspase activity. Whereas inhibition of the death receptor-mediated ERK1/2 activation was sufficient to sensitize the cells to apoptotic signaling from FasR and TRAIL-R, cells were still protected from apoptotic TNF-R1 signaling. The latter seemed to be due to the strong activation of the anti-apoptotic factor NF-kappaB, which remained inactive in FasR or TRAIL-R signaling. However, when the cells were sensitized with cycloheximide, which is sufficient to sensitize the cells also to apoptosis by TNF-R1 stimulation, we noticed that adenovirus-mediated expression of constitutively active MKK1 could rescue the cells from apoptosis induced by the respective receptors by preventing caspase-8 activation. Taken together, our results show that ERK1/2 has a dominant protecting effect over apoptotic signaling from the death receptors. This protection, which is independent of newly synthesized proteins, acts in all cases by suppressing activation of the caspase effector machinery.