Functional motor recovery is improved due to local placement of GDNF microspheres after delayed nerve repair

The majority of bioengineering strategies to promote peripheral nerve regeneration after injury have focused on therapies to bridge large nerve defects while fewer therapies are being developed to treat other nerve injuries, such as nerve transection. We constructed delivery systems using fibrin gels containing either free GDNF or polylactide–glycolic acid (PLGA) microspheres with GDNF to treat delayed nerve repair, where ELISA verified GDNF release. We determined the formulation of microspheres containing GDNF that optimized nerve regeneration and functional recovery in a rat model of delayed nerve repair. Experimental groups underwent delayed nerve repair and treatment with GDNF microspheres in fibrin glue at the repair site or control treatments (empty microspheres or free GDNF without microspheres). Contractile muscle force, muscle mass, and MUNE were measured 12 weeks following treatment, where GDNF microspheres (2 weeks formulation) were superior compared to either no GDNF or short‐term release of free GDNF to nerve. Nerve histology distal to the repair site demonstrated increased axon counts and fiber diameters due to GDNF microspheres (2 weeks formulation). GDNF microspheres partially reversed the deleterious effects of chronic nerve injury, and recovery was slightly favored with the 2 weeks formulation compared to the 4 weeks formulation. Biotechnol. Bioeng. 2013; 110: 1272–1281. © 2012 Wiley Periodicals, Inc.     

Persistence of bactericidal antibodies following early infant vaccination with a serogroup B meningococcal vaccine and immunogenicity of a preschool booster dose

Background:

The multicomponent serogroup B meningococcal (4CMenB) vaccine was recently licensed for use in Europe. There are currently no data on the persistence of bactericidal antibodies induced by use of this vaccine in infants. Our objective was to evaluate serogroup B–specific bactericidal antibodies in children aged 40–44 months previously vaccinated at 2, 4, 6 and 12 months of age.

Methods:

Participants given 4 doses of 4CMenB as infants received a fifth dose of the vaccine at 40–44 months of age. Age-matched participants who were MenB vaccine–naive received 4CMenB and formed the control group. We evaluated human complement serum bactericidal activity (hSBA) titres at baseline and 1 month after each dose of 4CMenB.

Results:

Before a booster dose at enrolment, 41%–76% of 17 participants previously vaccinated with 4CMenB in infancy had hSBA titres of 4 or greater against 4 reference strains. Before vaccination in the control group (n = 40) these proportions were similar for strains 44/76-SL (63%) and {"type":"entrez-nucleotide","attrs":{"text":"M10713","term_id":"209124","term_text":"M10713"}}M10713 (68%) but low for strains NZ98/254 (0%) and 5/99 (3%). A booster dose in the 4CMenB-primed participants generated greater increases in hSBA titres than in controls.

Interpretation:

As has been observed with other meningococcal vaccines, bactericidal antibodies waned after vaccination with 4CMenB administered according to an approved infant vaccination schedule of 2, 4, 6 and 12 months of age, but there was an anamnestic response to a booster dose at 40–44 months of age. If 4CMenB were introduced into routine vaccination schedules, assessment of the need for a booster dose would require data on the impact of these declining titres on vaccine effectiveness. ClinicalTrials.gov, no. {"type":"clinical-trial","attrs":{"text":"NCT01027351","term_id":"NCT01027351"}}NCT01027351A vaccine against serogroup B meningococcus has recently been licensed for use in Europe¹ and is being considered for licensure in Canada. This vaccine, known as multicomponent serogroup B meningococcal (4CMenB) vaccine, consists of 3 recombinant proteins: factor H binding protein (fHbp), Neisseria adhesin A (NadA) and Neisseria heparin binding antigen (NHBA) combined with detoxified outer membrane vesicles from the strain responsible for an epidemic of serogroup B meningococcal disease in New Zealand (NZ98/254). Clinical trials of 4CMenB have shown it to be immunogenic against reference strains selected to speciScally express one of the vaccine antigens.^2–6 On the basis of these trials, the approved schedule for infants aged 2 to 5 months is 3 doses given at least 1 month apart, with a booster dose given at 12 to 23 months of age.⁷ The persistence of vaccine-induced antibodies throughout childhood following this booster dose is unknown, but it is particularly relevant because the incidence of invasive serogroup B meningococcal disease in children aged 1 to 4 years is second only to the incidence in children less than 1 year of age.⁸In this study, we assessed the persistence of these bactericidal antibodies in children aged 40–44 months who had previously received either 4CMenB or a vaccine containing the recombinant proteins alone (recombinant protein serogroup B meningococcal [rMenB] vaccine) at 2, 4, 6 and 12 months of age.³ We also assessed the immunogenicity and reactogenicity of a booster dose.     

The Effect of Gestational Age and Labour on Markers of Lipid and Protein Oxidation in Cord Plasma

There are many potential sources of reactive oxidants around the time of birth and pre-term infants are considered to be particularly vulnerable to oxidative injury. To gain insight into these processes, we have measured biomarkers of lipid and protein oxidation in umbilical cord plasma and related concentrations to mode of delivery and gestational age. Protein carbonyls were measured by ELISA and malondialdehyde (MDA) by HPLC after reaction with thiobarbituric acid, for 54 pre-term (≤36 weeks gestational age) and 43 term infants. Protein carbonyls were significantly lower in pre-term (median for <32 weeks gestational age 0.048?nmol/mg protein) than in term infants (0.105?nmol/mg, p=0.004), and were unrelated to mode of delivery. In contrast, MDA concentrations were higher in the very pre-term (<32 weeks gestation) group (2.47 compared with 1.83?μM for term infants, p<0.0001). MDA concentrations were higher in infants who were born with labour compared with elective caesarean section. Pre-eclampsia in the mother was associated with higher cord blood MDA concentrations. The MDA results are consistent with other studies of this marker and could be interpreted as indicating increased oxidative stress associated with prematurity and labour. However, the lower protein carbonyls in pre-term infants would lead to an opposite interpretation. More information is needed on the source and fate of these and other biomarkers before drawing strong conclusions on how they reflect oxidative stress in this and other clinical situations.     

Mesopredator trophodynamics on thermally stressed coral reefs

Coral Reefs - Ecosystems are becoming vastly modified through disturbance. In coral reef ecosystems, the differential susceptibility of coral taxa to climate-driven bleaching is predicted to shift...     

Use of SSCP analysis to identify germline mutations in HNPCC families fulfilling the Amsterdam criteria

Hereditary non-polyposis colorectal cancer (HNPCC) is a clinical syndrome characterised by an inherited predisposition to early onset colorectal and uterine cancers and an increased incidence of other cancers. It is caused by germline defects in the human mismatch repair genes. Defects in two of the known mismatch repair genes (namely hMSH2 and hMLH1) account for over 90% of mutations found in HNPCC families. In this study we have identified 14 families that fulfilled the clinical criteria for HNPCC and screened the hMSH2 and hMLH1 genes for germline mutations using single-strand conformational polymorphism (SSCP) analysis and DNA sequencing. Seven mutations were identified. Of these, there were five frameshifts, one missense mutation and a further novel mutation that involved separate transition and transversion changes in successive amino acid residues. Three of the mutations were in hMSH2 and four in hMLH1. The identification of germ-line mutations in an HNPCC family enables targeted surveillance and the possibility of early curative intervention. SSCP is a simple and effective method for identifying most mutations in the human mismatch repair genes using DNA from fresh, frozen or archival material. Received: 24 July 1996 / Revised: 26 September 1996     

The cellular and molecular basis of peripheral nerve regeneration

Functional recovery from peripheral nerve injury and repair depends on a multitude of factors, both intrinsic and extrinsic to neurons. Neuronal survival after axotomy is a prerequisite for regeneration and is facilitated by an array of trophic factors from multiple sources, including neurotrophins, neuropoietic cytokines, insulin-like growth factors (IGFs), and glial-cell-line-derived neurotrophic factors (GDNFs). Axotomized neurons must switch from a transmitting mode to a growth mode and express growth-associated proteins, such as GAP-43, tubulin, and actin, as well as an array of novel neuropeptides and cytokines, all of which have the potential to promote axonal regeneration. Axonal sprouts must reach the distal nerve stump at a time when its growth support is optimal. Schwann cells in the distal stump undergo proliferation and phenotypical changes to prepare the local environment to be favorable for axonal regeneration. Schwann cells play an indispensable role in promoting regeneration by increasing their synthesis of surface cell adhesion molecules (CAMs), such asN-CAM, Ng-CAM/L1, N-cadherin, and L2/HNK-1, by elaborating basement membrane that contains many extracellular matrix proteins, such as laminin, fibronectin, and tenascin, and by producing many neurotrophic factors and their receptors. However, the growth support provided by the distal nerve stump and the capacity of the axotomized neurons to regenerate axons may not be sustained indefinitely. Axonal regeneration may be facilitated by new strategies that enhance the growth potential of neurons and optimize the growth support of the distal nerve stump in combination with prompt nerve repair.     

High inter-individual variability of serum xanthine oxidoreductase activity in IBD patients

Objectives: Thiopurines play an essential role in the management of inflammatory bowel diseases (IBD, i.e. Crohn's disease and ulcerative colitis). Over the past decade, several strategies to optimize treatment with thiopurines have been evaluated, including co-administration of allopurinol, a xanthine-oxidoreductase (XO) inhibitor, to low-dose thiopurine therapy. We aimed to assess the inter-individual variability of XO-activity between IBD-patients.

Methods: We assessed XO activity in serum of IBD-patients of two medical centers in The Netherlands using the Amplex® Red Xanthine/Xanthine Oxidase Assay Kit, which measures the superoxide formation in a coupled reaction to the red-fluorescent oxidation product, resofurine.

Results: We observed a high inter-individual variability of XO-activity in 119 patients, with a median activity of 16 µU/ml/hour (range 1–85 µU/ml/hour). The XO-activity was influenced by gender (male 19.5 vs. female 14.0 µU/ml/hour, p < 0.01), patient's age (Pearson's correlation r = 0.21, p = 0.02) and duration of IBD (r = 0.23, p = 0.01). The XO activity was not affected by the type of IBD, smoking status, body mass index or (type of) thiopurine use (p > 0.05).

Conclusions: There is a high inter-individual variability of XO-activity in IBD-patients; XO-activity is positively associated with male gender and patient's age.     

Combined 1H-Detected Solid-State NMR Spectroscopy and Electron Cryotomography to Study Membrane Proteins across Resolutions in Native Environments

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