Organ culture of pig cornea: biochemical analyses of mid-term-stored corneal tissue

Freshly prepared pig corneas were cultured at 22 degrees C in TC 199 medium supplemented with HEPES buffer, antibiotics and 10% sterile pig blood serum. The cultures were maintained in a closed system up to 30 days. The hydration as measured by wet and dry weights increased from 80 to 94% after 2 weeks of storage. Glucose decreased slowly and continuously during the culture time by 0.32 mmol in 30 days. This was equivalent to 11 mumol/day, 0.46 mumol/h and finally 0.264 mumol/h/cm2. Lactate increased in the culture accordingly by 0.34 mumol/h/cm2. In the corneal epithelium of the cultured tissues the glucose levels--normally at about 5 mumol/g--equilibrated with those of the medium during the first 10 days; later the epithelial glucose levels increased up to 20-30 mumol/g. The glycogen content of the epithelium remained constant for the first 10 days of storage. The ATP/ADP ratios in the corneal epithelium initially decreased but later recovered to values of about 12. The pO2 in the culture system decreased from 156 to 120 mm Hg, which is equivalent to an oxygen consumption of 7.41 microliters O2/h/cm2. The CO2 production initiating from a level of 16.6 mm Hg was 4.88 microliters/h/cm2. The data showed that the cornea was viable in this culture system for 30 days.     

Experimental autoimmune encephalomyelitis in mice lacking glial fibrillary acidic protein is characterized by a more severe clinical course and an infiltrative central nervous system lesion.

Insights into the role of the astrocyte intermediate filament protein, glial fibrillary acidic protein (GFAP), have only recently emerged with reports on subtle abnormalities in GFAP-deficient mice, including the documentation of defective long-term maintenance of central nervous system myelination. Here, we extend these observations by examining the astroglial response in GFAP-/- mice with autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. Clinically, the monophasic disease was more severe in GFAP-/- mice than in wild-type littermates despite increased remyelination in the former. More in keeping with the clinical course was the observation of an infiltrative EAE lesion in GFAP-/- mice. GFAP-/- astrocytes had a reduced cytoarchitectural stability as evidenced by less abundant and irregularly spaced hemidesmosomes. The blunt GFAP-/- astrocyte processes possessed intermediate filaments consisting mainly of vimentin, though to a lesser degree than in the wild-type. In contrast, in wild-type littermates, GFAP was most abundant and nestin occurred at lower levels. Taken together, the present study introduces the novel concepts that GFAP plays an important role in the control of clinical disease associated with formation of a clearly defined edge to the EAE lesion and that GFAP is operative in the regulation of the intermediate filament components in reactive fibrillary astrogliosis.     

The influence of bacterial contaminations on the biodegradation of PLA implants

Metal implants employed in orthopaedic surgery have certain disadvantages. Intensive research work is therefore being done in the field of biodegradable implants, the behavior of which in the case of possible contamination or infection at the operation site has not yet been studied. In-vitro experiments on PLA-test bodies were performed to clarify the influence of bacteria on the polymer degradation. The investigated parameters were germ growth, course of the pH-value of the culture media, bending stiffness of the PLA-test bodies and the decrease in their molecular weight. The experiments performed did not demonstrate an accelerated degradation of PLA specimen in vitro incubated in different bacterial contaminated media. Therefore bacterial contamination may possibly not lead to a premature collapse of the PLA used in connection with fracture treatment by biodegradable osteosynthesis implants.     

Cyclin E1 controls proliferation of hepatic stellate cells and is essential for liver fibrogenesis in mice

Liver fibrogenesis is associated with the transition of quiescent hepatocytes and hepatic stellate cells (HSCs) into the cell cycle. Exit from quiescence is controlled by E-type cyclins (cyclin E1 [CcnE1] and cyclin E2 [CcnE2]). Thus, the aim of the current study was to investigate the contribution of E-type cyclins for liver fibrosis in man and mice. Expression of CcnE1, but not of its homolog, CcnE2, was induced in fibrotic and cirrhotic livers from human patients with different etiologies and in murine wild-type (WT) livers after periodical administration of the profibrotic toxin, CCl(4) . To further evaluate the potential function of E-type cyclins for liver fibrogenesis, we repetitively treated constitutive CcnE1(-/-) and CcnE2(-/-) knock-out mice with CCl(4) to induce liver fibrosis. Interestingly, CcnE1(-/-) mice were protected against CCl(4) -mediated liver fibrogenesis, as evidenced by reduced collagen type I α1 expression and the lack of septum formation. In contrast, CcnE2(-/-) mice showed accelerated fibrogenesis after CCl(4) treatment. We isolated primary HSCs from WT, CcnE1(-/-) , and CcnE2(-/-) mice and analyzed their activation, proliferation, and survival in vitro. CcnE1 expression in WT HSCs was maximal when they started to proliferate, but decreased after the cells transdifferentiated into myofibroblasts. CcnE1(-/-) HSCs showed dramatically impaired survival, cell-cycle arrest, and strongly reduced expression of alpha smooth muscle actin, indicating deficient HSC activation. In contrast, CcnE2-deficient HSCs expressed an elevated level of CcnE1 and showed enhanced cell-cycle activity and proliferation, compared to WT cells. Conclusions: CcnE1 and CcnE2 have antagonistic roles in liver fibrosis. CcnE1 is indispensable for the activation, proliferation, and survival of HSCs and thus promotes the synthesis of extracellular matrix and liver fibrogenesis. (HEPATOLOGY 2012;56:1140-1149).     

Phase I trial of a novel human monoclonal antibody mAb216 in patients with relapsed or refractory B-cell acute lymphoblastic leukemia

Background

This phase I trial was conducted to determine the safety and pharmacokinetics of monoclonal antibody 216, a human monoclonal Immunoglobulin M antibody targeting a linear B-cell lactosamine antigen, administered alone and in combination with vincristine in patients with relapsed or refractory B-cell acute lymphoblastic leukemia, and to preliminarily assess tumor targeting and efficacy.

Design and Methods

Three cohorts of patients received escalating doses of monoclonal antibody 216 administered as an intravenous infusion. In the case of poor response to the first dose of monoclonal antibody 216 alone, defined as less than 75% reduction in peripheral blood blast count, a second dose of the antibody with vincristine was given between days 4 and 7. Responses were assessed weekly until day 35. Serum concentration of monoclonal antibody 216 was measured before and after infusion. Monoclonal antibody 216 targeting was determined with an anti-idiotypic antibody to monoclonal antibody 216 and preliminary efficacy was analyzed by changes in peripheral blood blasts.

Results

Thirteen patients were enrolled. One episode of grade 3 epistaxis was the only dose-limiting toxicity observed. All patients showed a poor response to the first monoclonal antibody 216 infusion with a decrease in peripheral blasts from 6–65% in 9 patients. In 8 patients, addition of vincristine to monoclonal antibody 216 resulted in an average reduction of the peripheral blasts of 81%. One patient without peripheral blasts achieved a hypoplastic marrow without evidence of leukemia after one infusion of monoclonal antibody 216 and monoclonal antibody 216/vincristine each. Monoclonal antibody 216 was detected on peripheral blasts in all patients.

Conclusions

Treatment with monoclonal antibody 216 in combination with vincristine is feasible and well tolerated in patients with relapsed or refractory B-cell acute lymphoblastic leukemia. Binding of monoclonal antibody 216 to leukemic blasts was efficient, and favorable early responses were observed.     

Mammalian TRPV4 (VR-OAC) directs behavioral responses to osmotic and mechanical stimuli in Caenorhabditis elegans

All animals detect osmotic and mechanical stimuli, but the molecular basis for these responses is incompletely understood. The vertebrate transient receptor potential channel vanilloid subfamily 4 (TRPV4) (VR-OAC) cation channel has been suggested to be an osmo/mechanosensory channel. To assess its function in vivo, we expressed TRPV4 in Caenorhabditis elegans sensory neurons and examined its ability to generate behavioral responses to sensory stimuli. C. elegans ASH neurons function as polymodal sensory neurons that generate a characteristic escape behavior in response to mechanical, osmotic, or olfactory stimuli. These behaviors require the TRPV channel OSM-9 because osm-9 mutants do not avoid nose touch, high osmolarity, or noxious odors. Expression of mammalian TRPV4 in ASH neurons of osm-9 worms restored avoidance responses to hypertonicity and nose touch, but not the response to odorant repellents. Mutations known to reduce TRPV4 channel activity also reduced its ability to direct nematode avoidance behavior. TRPV4 function in ASH required the endogenous C. elegans osmotic and nose touch avoidance genes ocr-2, odr-3, osm-10, and glr-1, indicating that TRPV4 is integrated into the normal ASH sensory apparatus. The osmotic and mechanical avoidance responses of TRPV4-expressing animals were different in their sensitivity and temperature dependence from the responses of wild-type animals, suggesting that the TRPV4 channel confers its characteristic properties on the transgenic animals' behavior. These results provide evidence that TRPV4 can function as a component of an osmotic/mechanical sensor in vivo.     

Effects of serum and plasma matrices on multiplex immunoassays

Multiplexed fluorescence or electrochemiluminescence immunoassays of soluble cytokines are commonly performed in the context of human serum or plasma, to look for disease biomarkers and to monitor the immune system in a simple and minimally invasive way. These assays provide challenges due to the complexities of the matrix (serum or plasma) and the presence of many cytokines near the limit of detection of the assay. Here, we compare the readout of matched serum and plasma samples, which are generally correlated. However, a subset of cytokines usually have higher levels in serum, and the non-specific background is significantly increased in serum versus plasma. Presumably as a result of this non-specific background, disease-related decreases in low-abundance cytokines can sometimes be detected in plasma but not in serum. We further show, through spike recovery experiments, that both serum and plasma inhibit the readout of many cytokines, with some variability between donors, but with serum causing greater inhibition than plasma in many cases. Standard diluents from different vendors can partially reverse this inhibition to varying degrees. Dilution of samples can also partly overcome the inhibitory effect of the matrix. We also show that dilution is nonlinear and differentially affects various cytokines. Together, these data argue that (1) plasma is a more sensitive matrix for detecting changes in certain low-abundance cytokines; (2) calculation of concentrations in serum or plasma matrices is inherently inaccurate; and (3) dilution of samples should not be assumed to be linear, i.e., all comparisons need to be made among similarly diluted samples.