In vivo performance of a sol-gel glass-coated collagen

Synthetic bioactive materials offer possibilities to repair large tissue defects. It is well known that bioactivity, angiogenesis, and inflammation are key events in implant incorporation. Using glass-coated and glass-free collagen as potential bone graft substitutes, we carried out in vitro bioactivity and an in vivo angiogenesis and inflammation studies. The in vitro study showed bioactivity when the glass-coated samples were left in SBF for 5 days. This was confirmed by FTIR results, which presented P--O vibration bands characteristic of hydroxyapatite close to 1060 cm(-1) and 600 cm(-1). The in vivo response was evaluated following subcutaneous implantation of the biomaterial in the mouse dorsa. Angiogenesis, as determined by hemoglobin content extracted from implants 7 and 14 days after implantation, increased progressively in both glass-coated and glass-free collagen implants. However, vascularization was higher in the glass-coated collagen implants 14 days after implantation (mug Hb per mg wet tissue 6.0 +/- 0.3) compared with the glass-free group (1.6 +/- 0.1). The inflammatory process, determined by the levels of myeloperoxidase and N-acetylglucosaminidase, was similar for both implants. This study shows that glass-coated collagen implants hold osteogenic and angiogenic potential and may be used in clinical conditions requiring improvement of these biological processes.     

Haemorrhagic reactions elicited at sites of passive cutaneous anaphylaxis by the intravenous injection of aggregated γ-globulin

In guinea-pigs injected intradermally with a small amount of antibody and challenged 2 hours later, by the intravenous route, with a mixture of homologous antigen and aggregated γ-globulin, haemorrhagic reactions of the Arthus type develop at the sites of intradermal sensitization. This effect was obtained with γ-globulins of different species (human, rabbit and horse) by using different techniques for aggregation (heat, mercaptoethanol—urea and bis-diazobenzidine) and was always correlated with the ability of the aggregated globulin to fix complement.

Fluorescein labelled aggregates of γ-globulin were detectable in the wall of vessels at sensitized sites.

In experiments performed with guinea-pig antibodies, the localizing effect was observed only with γ₁, whereas the γ₂, Arthus-producing fraction proved completely ineffective.

Histamine and histamine liberators are not sufficient for eliciting the effect obtained with sensitizing antibody plus homologous antigen. It is postulated, therefore, that other effects occurring at the site of specific sensitization may also be responsible for the phenomenon.

     

Modulation of cardiac mitochondrial permeability transition and apoptotic signaling by endurance training and intermittent hypobaric hypoxia

Background

Modulation of the mitochondrial permeability transition pore (MPTP) and inhibition of the apoptotic signaling are critically associated with the cardioprotective phenotypes afforded by both intermittent hypobaric-hypoxia (IHH) and endurance-training (ET). We recently proposed that IHH and ET improve cardiac function and basic mitochondrial capacity, although without showing addictive effects. Here we investigate whether a combination of IHH and ET alters cardiac mitochondrial vulnerability to MPTP and related apoptotic signaling.

Methods

Male Wistar rats were divided into normoxic-sedentary (NS), normoxic-exercised (NE, 1 h/day/5 week treadmill-running), hypoxic-sedentary (HS, 6000 m, 5 h/day/5 weeks) and hypoxic-exercised (HE) to study susceptibility to calcium-induced cardiac MPTP opening. Mitochondrial cyclophilin D (CypD), adenine nucleotide translocator (ANT), Bax and Bcl-2 protein contents were semi-quantified by Western blotting. Cardiac caspase 3-, 8- and 9-like activities were measured. Mitochondrial aconitase and superoxide dismutase (MnSOD) activity and malondialdehyde (MDA) and sulphydryl group (–SH) content were determined.

Results

Susceptibility to MPTP decreased in NE and HS vs. NS and even further in HE. The ANT content increased in HE vs. NS. Bcl-2/Bax ratio increased in NE and HS compared to NS. Decreased activities in tissue caspase 3-like (HE vs. NS) and caspase 9-like (HS and HE vs. NS) were observed. Mitochondrial aconitase increased in NE and HS vs. NS. No alterations between groups were observed for caspase 8-like activity, MnSOD, CypD, MDA and –SH.

Conclusions

Data confirm that IHH and ET modulate cardiac mitochondria to a protective phenotype characterized by decreased MPTP induction and apoptotic signaling, although without visible addictive effects as initially hypothesized.     

Hybridization signatures of gamma-irradiated murine fetal thymus organ culture (FTOC) reveal modulation of genes associated with T-cell receptor V(D)J recombination and DNA repair

In this study, we observed the occurrence of TRBV8.1-DB2.1 V(D)J recombination in murine fetal thymus organ culture (FTOC), in which the thymic microenvironment is mimicked. Since ionizing radiation affects T-cell development, we irradiated FTOCs with gamma rays to evaluate the modulation of genes implicated in TRBV8.1-BD2.1 rearrangements. The nylon cDNA microarray method was employed to monitor the expression of 9216 genes, which were organized in coexpression clusters. Clustering analysis showed similar expression profiling of genes implicated in the V(D)J recombination and DNA double strand break (DSB) repair processes such as XRCC4, RAG-2, Artemis and DNA-PK-cs, thus suggesting overlap between the two processes. The RUNX3 gene, whose coded protein binds to the enhancers of TR genes, was also modulated and the DNA cross-linking LR1 gene, which plays a role in the opening of hairpin DNA structures and whose expression pattern is similar to Artemis, may play a role in the control of V(D)J recombination. Furthermore, our data demonstrate that the FTOC model system and cDNA microarray method are useful tools to evidentiate genes that may play a role in both processes V(D)J recombination and DNA repair.     

Treatment of uncommon sites of focal primary hyperhidrosis: experience with pharmacological therapy using oxybutynin

OBJECTIVES:

Primary hyperhidrosis usually affects the hands, armpits, feet and cranio-facial region. Sweating in other areas is common in secondary hyperhidrosis (after surgery or in specific clinical conditions). Oxybutynin has provided good results and is an alternative for treating hyperhidrosis at common sites. Our aim was to evaluate the efficacy of oxybutynin as a treatment for primary sweating at uncommon sites (e.g., the back and groin).

METHODS:

This retrospective study analyzed 20 patients (10 females) who received oxybutynin for primary focal hyperhidrosis at uncommon sites. The subjects were evaluated to determine quality of life before beginning oxybutynin and six weeks afterward and they were assigned grades (on a scale from 0 to 10) to measure their improvement at each site of excessive sweating after six weeks and at the last consult.

RESULTS:

The median follow-up time with oxybutynin was 385 days (133-1526 days). The most common sites were the back (n = 7) and groin (n = 5). After six weeks, the quality of life improved in 85% of the subjects. Dry mouth was very common and was reported by 16 patients, 12 of whom reported moderate/severe dry mouth. Five patients stopped treatment (two: unbearable dry mouth, two: excessive somnolence and one: palpitations). At the last visit, 80% of patients presented with moderate/great improvement at the main sites of sweating.

CONCLUSION:

After six weeks, more than 80% of the patients presented with improvements in their overall quality of life and at the most important site of sweating. Side effects were common (80% reported at least one side effect) and caused 25% of the patients to discontinue treatment. Oxybutynin is effective for treating bothersome hyperhidrosis, even at atypical locations and most patients cope well with the side effects.     

Onset of promiscuous gene expression in murine fetal thymus organ culture

T-cell differentiation and induction of tolerance to self-antigens occurs mainly in the thymus. Thymic stromal cells, specifically medullary thymic epithelial cells, express a diverse set of genes encoding parenchymal organ-specific proteins. This phenomenon has been termed promiscuous gene expression (PGE) and has been implicated in preventing organ-specific autoimmunity by inducing T-cell tolerance to self antigens. Early thymopoiesis and the critical factors involved in T-cell differentiation can be reproduced in vitro by murine fetal thymus organ culture (FTOC), which mimics the natural thymic microenvironment. To evaluate the occurrence of PGE in FTOC, gene expression profiling during in vitro thymic development in BALB/c mice was performed using a set of nylon cDNA microarrays containing 9216 sequences. The statistical analysis of the microarray data (sam program) revealed the temporal repression and induction of 57 parenchymal and seven lymphoid organ-specific genes. Most of the genes analysed are repressed during early thymic development (15-17 days post-coitum). The expression of the autoimmune regulator (AIRE) gene at 16 days post-coitum marks the onset of PGE. This precedes the induction of parenchymal organ genes during the late developmental phase at 20 days post-coitum. The mechanism of T-cell tolerance induction begins during fetal development and continues into adulthood. Our findings are significant because they show a fine demarcation of PGE onset, which plays a central role in induction of T-cell tolerance.