Effects of fibrin pad hemostat on the wound healing process in vivo and in vitro

Fibrin Pad is a hemostatic pad designed to control surgical-related bleeding. It consists of a fully absorbable composite matrix scaffold coated with human-derived active biologics that immediately form a fibrin clot upon contact with targeted bleeding surfaces. Studies were conducted to investigate the effect of Fibrin Pad and its biologics-free composite matrix component (Matrix) on the wound healing process in in vitro and in vivo models. Fibrin Pad was evaluated in solid organ, soft tissue defects, and subcutaneous tissues. Immunocompromised rodents were used to avoid xeno-mediated responses. Extracts created from both materials were evaluated for biological activity using in vitro cell culture assays. Neither Fibrin Pad nor Matrix alone showed any inhibition of the wound healing of treated defect sites. An apparent accelerated healing was noted in the soft tissue and subcutaneous tissue defects with Fibrin Pad as compared to Matrix. Both materials showed desirable properties associated with tissue scaffolds. The in vitro study results show that Fibrin Pad extract can induce dose-dependent increases in fibroblast proliferation and migration. These studies confirm that the biologic components of Fibrin Pad can enhance wound healing processes in in vitro assays and fully support wound healing at the site of in vivo application.     

In vitro and in vivo antibacterial activity of tigecycline against Vibrio vulnificus

Background/purpose

The aim of this study is to investigate the role of tigecycline in Vibrio vulnificus infection.

Influence of polyamines on in vitro and in vivo features of aggressive and metastatic behavior by human breast cancer cells

Increased cellular activity of ornithine decarboxylase (ODC), the first and rate-limiting enzyme in polyamine (PA) synthesis, is an independent adverse prognostic factor for overall survival in human breast cancer [4], thus suggesting an important role for PA in tumor progression. The experiments presented here were designed to investigate the role of PA in invasion and metastasis, using the highly aggressive MDA-MB-435 and MDA-MB-231 human breast cancer cell lines. Administration of α-difluoromethylornithine (DFMO), an irreversible inhibitor of ODC, significantly reduced, in a dose-dependent manner, the invasiveness in matrigel of both MDA-MB-435 and MDA-MB-231 cells by ∼70%. DFMO treatment also inhibited (P<0.0001) `stellate' colony formation (an indicator of aggressive phenotype) by MDA-MB-435 cells plated in the matrigel outgrowth assay. Administration of DFMO (2% in drinking water) reduced the growth rate of both cell lines implanted orthotopically in nude mice. To evaluate metastasis while minimizing effects on proliferation, DFMO-treated mice were sacrificed later to allow their tumors to reach the same size of the tumors in the control mice. The most striking finding was that DFMO, while ineffective in reducing local invasion, nearly totally abolished (P=0.0152) pulmonary metastasis in mice bearing MDA-MB-435 xenografts. These results support a role of PA in promoting breast cancer aggressiveness, particularly with regard to the development of distant metastasis. Furthermore, the data suggest that PA involvement is distal to local invasion in the metastatic cascade. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification of Aspergillus tubingensis in a primary skin infection

Objective

Aspergillus section Nigri comprises a group of related species that include Aspergillus niger, A. welwitschiae, A. carbonarius, A. brasiliensis and A. tubingensis. Some of these species are morphologically very similar to A. niger but exhibit different patterns of susceptibility to antifungal agents; such is the case for A. tubingensis. Therefore, when diagnosing aspergillosis, it is important to identify the pathogen at the species level. This study aimed to identify the species of an Aspergillus spp. isolate (MM-82) obtained from a patient with a dermatosis localized to the right leg.

Mitochondrial inheritance in haploid × non-haploid crosses in Cryptococcus neoformans

In the basidiomycetous yeast Cryptococcus neoformans, fusants and meiotic progeny from haploid–haploid (HH) crosses between strains of mating type a (MAT a) and mating type alpha (MATα) typically inherit mitochondrial DNA (mtDNA) from the MAT a parent. In this study, we investigated the mtDNA inheritance pattern in haploid × non-haploid crosses. A total of 420 meiotic progeny and 173 fusants were obtained from five crosses and analyzed for two polymorphic mitochondrial markers. The percentage of meiotic progeny and fusants inheriting mtDNA from MATα or MATα/α parents ranged from 8 to 50%. The leakage was significantly greater than those observed in HH crosses, indicating that mtDNA inheritance is not uniparental in haploid × non-haploid crosses in C. neoformans. In addition, mtDNA leakage in the fusants, but not the meiotic progeny, of the MATα/α × MAT a cross was significantly higher than that in the MAT a/a × MATα cross, suggesting that the diploid parents with different mating types contribute differently in determining fusant mtDNA genotype in these crosses. Flow cytometry analysis revealed that meiotic progeny population of each cross was of mixed ploidy while the ploidy level of the selected fusants ranged from diploid to triploid.     

Hydrogel-based biomimetic environment for in vitro modulation of branching morphogenesis

The mechanical properties of the cellular microenvironment dramatically alter during tissue development and growth. Growing evidence suggests that physical microenvironments and mechanical stresses direct cell fate in developing tissue. However, how these physical cues affect the tissue morphogenesis remains a major unknown. We explain here that the physical properties of the cell and tissue microenvironment, biomimetically reproduced by using hydrogel, guide the tissue morphogenesis in the developmental submandibular gland (SMG). In particular, the softer gel enhances the bud expansion and cleft formation of SMG, whereas the stiffer gel attenuates them. These morphological changes in SMG tissue are led by soluble factors (FGF7/10) induction regulated by cell traction force derived from the tissue deformation. Our findings suggest that cells sense the mechanics of their surrounding environment and alter their properties for self-organization and the following tissue morphogenesis. Also, physically designed hydrogel material is a valuable tool for producing the biomimetic microenvironment to explore how physical cues affect tissue morphogenesis and to modulate tissue morphogenesis for in?vitro tissue synthesis.     

Determinants of 2,000 m rowing ergometer performance in elite rowers

This study examined the physiological determinants of performance during rowing over 2,000 m on an ergometer in finalists from World Championship rowing or sculling competitions from all categories of competion rowing (19 male and 13 female heavyweight, 4 male and 5 female lightweight). Discontinuous incremental rowing to exhaustion established the blood lactate threshold, maximum oxygen consumption (V˙O_2max) and power at V˙O_2max; five maximal strokes assessed maximal force, maximal power and stroke length. These results were compared to maximal speed during a 2,000 m ergometer time trial. The strongest correlations were for power at V˙O_2max, maximal power and maximal force (r=0.95; P<0.001). Correlations were also observed for V˙O_2max (r=0.88, P<0.001) and oxygen consumption (V˙O₂) at the blood lactate threshold (r=0.87, P=0.001). The physiological variables were included in a stepwise regression analysis to predict performance speed (metres per second). The resultant model included power at V˙O_2max, V˙O₂ at the blood lactate threshold, power at the 4 mmol·l^–1 concentration of blood lactate and maximal power which together explained 98% of the variance in the rowing performance over 2,000 m on an ergometer. The model was validated in 18 elite rowers, producing limits of agreement from –0.006 to 0.098 m·s^–1 for speed of rowing over 2,000 m on the ergometer, equivalent to times of –1.5 to 6.9 s (–0.41% to 1.85%). Together, power at V˙O_2max, V˙O₂ at the blood lactate threshold, power at 4 mmol·l^–1 blood lactate concentration and maximal power could be used to predict rowing performance. Electronic Publication     

Stress proteins of 70 kDa in chronically exercised skeletal muscle

Skeletal muscle fibres of untrained animals experience a stress response following exercise. This study was aimed at investigating whether chronic exercise modulates stress proteins of 70 kDa (HSP70s) in skeletal muscle. In the soleus muscle of Wistar rats, adherence to an incremental programme of treadmill running (IPTR) of 3 months duration up-regulated the levels of the beta-subunit of the mitochondrial F1-ATPase and those of HSP72, GRP75 and GRP78. Neither beta-F1-ATPase nor sarcoplasmic reticulum Ca2+-ATPase levels changed with training in the extensor digitorum longus (EDL) muscle. However, HSP70s increased during training. In soleus muscle slices of animals sacrificed 3 days after completing the IPTR, HSP72 and GRP75 were synthesized at lower rates than in sedentary animals while the GRP78 synthesis rate increased. Trained, rested animals also experienced a stress response following acute exercise of lower intensity than that of the actual training sessions. The data suggest that up-regulation of HSP70s by chronic exercise depends upon continued physical activity. Furthermore, the inverse correlation between levels and rates of synthesis of HSP72 during rest periods suggests the operation of a feedback regulatory loop aimed at reestablishing the threshold levels characteristic of unstressed fibres.     

Genetic heterogeneity of megaloblastic anaemia type 1 in Tunisian patients

Megaloblastic anaemia 1 (MGA1) is a rare autosomal recessive condition characterized by selective intestinal vitamin B12 malabsorption and proteinuria. More than 200 MGA1 patients have been identified worldwide, but the disease is relatively prevalent in Finland, Norway and several Eastern Mediterranean regions. MGA1 is genetically heterogeneous and can be caused by mutations in either the cubilin (CUBN) or the amnionless (AMN) gene. In the present study we investigated the molecular defect underlying MGA1 in nine Tunisian patients belonging to six unrelated consanguineous families. Haplotype and linkage analyses, using microsatellite markers surrounding both CUBN and AMN genes, indicated that four out of the six families were likely to be linked to the CUBN gene. Patients from these families were screened for the Finnish, Mediterranean and Arabian mutations already published. None of the screened mutations could be detected in our population. One family showed a linkage to AMN gene. Direct screening of the AMN gene allowed the identification of the c.208-2A>G mutation, previously described in a Jewish Israeli patient of Tunisian origin and in Turkish patients. This suggests that the c.208-2A>G mutation may derive from a single Mediterranean founder ancestor. For the last family, haplotype analysis excluded both CUBN and AMN genes, suggesting the existence of a third locus that may cause MGA1.     

Nanoprobes for in vitro diagnostics of cancer and infectious diseases

The successful and explosive development of nanotechnology is significantly impacting the fields of biology and medicine. Among the spectacular developments of nanobiotechnology, interest has grown in the use of nanomaterials as nanoprobes for bioanalysis and diagnosis. Herein, we review state-of-the-art nanomaterial-based probes and discuss their applications in in vitro diagnostics (IVD) and challenges in bringing these fields together. Major classes of nanoprobes include quantum dots (QDs), plasmonic nanoparticles, magnetic nanoparticles, nanotubes, nanowires, and multifunctional nanomaterials. With the advantages of high volume/surface ratio, surface tailorability, multifunctionality, and intrinsic properties, nanoprobes have tremendous applications in the areas of biomarker discovery, diagnostics of infectious diseases, and cancer detection. The distinguishing features of nanoprobes for in vitro use, such as harmlessness, ultrasensitivity, multiplicity, and point-of-care use, will bring a bright future of nanodiagnosis.     

Evaluation of the potential of Trichoderma viride in the control of fungal pathogens of Roselle (Hibiscus sabdariffa L.) in vitro

The potential of Trichoderma viride as a bio-control agent was evaluated in vitro against Roselle pathogens i.e. Phoma exigua, Fusarium nygamai and Rhizoctonia solani [1] using the dual culture technique. Volatile and non-volatile inhibitors of Trichoderma were also evaluated for this purpose. T. viride [2] was shown to have a marked inhibitory effect on the tested pathogens in vitro. Maximum inhibition occurred against P. exigua, with 71.76% reduction in mycelial radial growth. The three pathogens, P. exigua, F. nygamai and R. solani were also found to be susceptible to the volatile inhibitors produced by T. viride, giving rise to growth inhibition of about 68% in each case. When T. viride non-volatile metabolites were tested against the pathogens, maximum inhibition occurred against R. solani (73.95% mycelial growth inhibition), followed by P. exigua (37.17% inhibition). The inhibitory effect of the non-volatile metabolites on F. nygamai was, however, minimal.     

Functional and epigenetic studies reveal multistep differentiation and plasticity of in vitro-generated and in vivo-derived follicular T helper cells

Follicular T helper (Tfh) cells provide critical help to B cells for germinal center (GC) formation. Mutations affecting SLAM-associated protein (SAP) prevent GC formation because of defective T?cell-B cell interactions, yet effects on Tfh cell differentiation remain unclear. We describe the in?vitro differentiation of functionally competent "Tfh-like" cells that expressed interleukin-21, Tfh cell markers, and Bcl6 and rescued GC formation in SAP-deficient hosts better than other T helper (Th) cells. SAP-deficient Tfh-like cells appeared virtually indistinguishable from wild-type, yet failed to support GCs in?vivo. Interestingly, both Tfh-like and in?vivo-derived Tfh cells could produce effector cytokines in response to polarizing conditions. Moreover, Th1, Th2, and Th17 cells could be reprogrammed to obtain Tfh cell characteristics. ChIP-Seq analyses revealed positive epigenetic markings on Tbx21, Gata3, and Rorc in Tfh-like and ex?vivo Tfh cells and on Bcl6 in non-Tfh cells, supporting the concept of plasticity between Tfh and other Th cell populations.     

Multi-functional graphene as an in vitro and in vivo imaging probe

A strategy has been developed for the synthesis of multi-functional graphene (MFG) using green synthetic approach and explored its biomedical application as a promising fluorescent marker for in vitro and in vivo imaging. In-situ microwave-assisted reduction and magnetization process was adopted to convert the graphene oxide into magnetic graphene within 1 min, which was further covalently modified to build a polyacrylic acid (PAA) bridge for linking the fluorescein o-methacrylate (FMA) to yield MFG with water-dispersibility (∼2.5 g/l) and fluorescence property (emission maximum at 526 nm). The PAA bridges also functions to prevent graphene-induced fluorescence quenching of conjugated FMA. The extent of reduction, magnetization, and functionalization was confirmed with TEM, AFM, Raman, XPS, FT-IR, TGA, and SQUID measurements. In vitro cytotoxicity study of HeLa cells reveal that MFG could stand as a biocompatible imaging probe with an IC₅₀ value of ∼100 μg/ml; whereas in vivo zebrafish study does not induce any significant abnormalities nor affects the survival rate after microinjection of MFG. Confocal laser scanning microscopy images reveals that MFG locates only in the cytoplasm region and exhibits excellent co-localization and biodistribution from the head to tail in the zebrafish. Our results demonstrate the applicability of graphene based fluorescence marker for intracellular imaging and, more significantly, as well as whole-animal imaging. Hence, MFG could preferentially serve as a dual functional probe in biomedical diagnostics.