Testicular immune privilege promotes transplantation tolerance by altering the balance between memory and regulatory T cells

Immune responses are suppressed in immunologically privileged sites, which may provide a unique opportunity to prolong allograft survival. However, it is unknown whether testicular immune privilege promotes transplantation tolerance. Mechanisms underlying immune privilege are also not well understood. Here we found that islet transplantation in the testis, an immunologically privileged site, generates much less memory CD8(+) T cells but induces more Ag-specific CD4(+)CD25(+) regulatory T cells than in a conventional site. These CD4(+)CD25(+) cells exhibited the suppression of alloimmune responses in vivo and in vitro. Despite the immune regulation, intratesticular islet allografts all were rejected within 42 days after transplantation although they survived longer than renal subcapsular islet allografts. However, blocking CD40/CD40L costimulation induced the tolerance of intratesticular, but not renal subcapsular, islet allografts. Tolerance to intratesticular islet allografts spread to skin allografts in the non-privileged sites. Either transfer of memory CD8(+) T cells or deletion of CD25(+) T cells in vivo broke islet allograft tolerance. Thus, transplantation tolerance requires both costimulatory blockade, which suppresses acute allograft rejection, and a favorable balance between memory and regulatory T cells that could favorably prevent late allograft failure. These findings reveal novel mechanisms of immune privilege and provide direct evidence that testicular immune privilege fosters the induction of transplantation tolerance to allografts in both immunologically privileged and non-privileged sites.     

Calpain activates caspase-3 during UV-induced neuronal death but only calpain is necessary for death

While caspases have been strongly implicated in delayed neuronal death in a variety of experimental paradigms, other proteases such as calpain can also contribute to neuronal death. To evaluate the relative roles of caspase and calpain, we used a model system wherein UV treatment induced moderate or severe delayed cortical neuronal death, as quantified by propidium iodide and calcein AM. UV treatment led to increases in both caspase and calpain activation. Calpain inhibitor III (MDL-28170) reduced caspase activation, suggesting that caspase activation was mediated by calpain. Calpain contributed to neuronal death, as indicated by strong neuroprotection provided by calpain inhibitor III, calpeptin, or Ca2+-free medium. In contrast, caspase inhibitors were not neuroprotective. These results suggest that UV neurotoxicity is mediated by a loss of Ca2+ homeostasis which leads to a calpain-dependent, caspase-independent cell death. That calpain, but not caspase, may mediate death in instances involving the activation of both proteases may have relevance to other neuronal death models.     

Egyptian propolis: 3. Antioxidant,antimicrobial activities and chemical composition of propolis from reclaimed lands

The free radical scavenging effect of two propolis samples collected from reclaimed land, Egypt as well as of vitamin C and caffeic acid in 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical system was determined. The antimicrobial (Staphylococcus aureus; Escherichia coli and Candida albicans) activity was also investigated. The results of the free radical scavenging effect of El-Saff and Ismailia propolis showed a concentration-dependent activity. The antioxidant activity was varied according to the examined material. It was obvious that caffeic acid and vitamin C showed the highest activity if compared with the propolis samples. El- Saff propolis had a higher antioxidant activity than Ismailia propolis, it showed a higher antibacterial activity against Staphylococcus aureus and a higher anti-fungal activity against Candida albicans. While the Ismailia propolis had a higher antibacterial activity against Escherichia coli, than El-Saff propolis. The chemical composition of propolis samples was investigated by GC/MS, where 75 compounds were identified, 22 being new for propolis. The Ismailia propolis was characterized by the presence of a highly significant amount of aromatic acid esters (47.3%) and triterpenoids (17.3%), while El-Saff propolis contained 3% and 1.9% respectively. The new esters belonged to 4-methoxyhydrocinnamic acid, hydroferulic acid and ferulic acid. El-Saff propolis had a very high significant amount (27%) of 2,6-bis-(pentanyloxy)-4-pentanylphenethanol, which is also a new compound for propolis.     

Egyptian propolis: 2. Chemical composition,antiviral and antimicrobial activities of East Nile Delta propolis

Three propolis samples from East Nile Delta, Egypt were collected. Propolis samples were investigated by GC/MS,103 compounds were identified, 20 being new for propolis. Dakahlia propolis was a typical poplar propolis but it contained two new caffeate esters and two new triterpenoids. Ismailia propolis was characterized by the presence of new triterpenic acid methyl esters and it did not contain any aromatic acids, esters and flavonoids. Sharkia propolis was characterized by the presence of caffeate esters only, some di- and triterpenoids. The antiviral (Infectious Bursal Disease Virus and Reo-Virus) and antimicrobial (Staphylococcus aureus; Escherichia coli and Candida albicans) activities of propolis samples were investigated. Dakahlia propolis showed the highest antiviral activity against Infectious Bursal Disease Virus (IBDV) and the highest antibacterial activity against Escherichia coli and the highest antifungal activity against Candida albicans. While Ismailia propolis had the highest antiviral activity against Reo-virus. Sharkia propolis showed the highest antibacterial activity against Staphylococcus aureus and moderate antiviral activity against infectious bursal disease virus and reovirus.     

Effects of culture conditions on enhancement of 2,4-dinitrotoluene degradation by Burkholderia engineered with the Vitreoscilla hemoglobin gene

Growth and degradation of 2,4-dinitrotoluene (2,4-DNT) were compared in liquid cultures in shake flasks for Burkholderia sp. strain DNT and strain DNT engineered to produce Vitreoscilla (bacterial) hemoglobin (strain YV1). Parameters varied included aeration rate, initial 2,4-DNT concentration (50 and 200 ppm), and concentration and type of cosubstrate (yeast extract, succinate, casamino acids, and tryptic soy broth). 2,4-DNT degradation increased with increasing cosubstrate concentration and was greater for strain YV1 than strain DNT under most conditions tested; the greatest advantages of YV1 (up to 3.5-fold) occurred under limited aeration. A third strain (YV1m), derived from YV1 by repeated growth on 2,4-DNT-containing medium, demonstrated increased 2,4-DNT degradation (up to 1.3-fold compared to YV1) at 200 ppm 2,4-DNT. The growth profiles of the three strains with respect to each other were in general similar to those of the degradation patterns of 2,4-DNT.     

Isoflavonoids and flavone glycosides from rhizomes of Iris carthaliniae

Two new isoflavonoid biosides, tectorigenin 4′-glucosyl (1→6)glucoside and iristectorigenin B 7-glucosyl (1→6)glucoside, a new isoflavonoid monoside, 4′-methyltectorigenin 7-glucoside and a new flavone glucoside, 6,4′-dimethoxy-5-hydroxyflavone 7-glucoside, together with tectoridin and tectorigenin 4′-glucoside were isolated from rhizomes of Iris carthaliniae. The structures of the isolated compounds were determined by NMR spectral analysis.     

The Impact of Myeloperoxidase and Activated Macrophages on Metaphase II Mouse Oocyte Quality

Myeloperoxidase (MPO), an abundant heme-containing enzyme present in neutrophils, monocytes, and macrophages, is produced in high levels during inflammation, and associated with poor reproductive outcomes. MPO is known to generate hypochlorous acid (HOCl), a damaging reactive oxygen species (ROS) utilizing hydrogen peroxide (H₂O₂) and chloride (Cl^-). Here we investigate the effect of activated immune cells and MPO on oocyte quality. Mouse metaphase II oocytes were divided into the following groups: 1) Incubation with a catalytic amount of MPO (40 nM) for different incubation periods in the presence of 100 mM Cl^- with and without H₂O₂ and with and without melatonin (100 μM), at 37°C (n = 648/648 total number of oocytes in each group for oocytes with and without cumulus cells); 2) Co-cultured with activated mouse peritoneal macrophage and neutrophils cells (1.0 x 10⁶ cells/ml) in the absence and presence of melatonin (200 μM), an MPO inhibitor/ROS scavenger, for different incubation periods in HTF media, at 37°C (n = 200/200); 3) Untreated oocytes incubated for 4 hrs as controls (n = 73/64). Oocytes were then fixed, stained and scored based on the microtubule morphology and chromosomal alignment. All treatments were found to negatively affect oocyte quality in a time dependent fashion as compared to controls. In all cases the presence of cumulus cells offered no protection; however significant protection was offered by melatonin. Similar results were obtained with oocytes treated with neutrophils. This work provides a direct link between MPO and decreased oocyte quality. Therefore, strategies to decrease MPO mediated inflammation may influence reproductive outcomes.     

Environment friendly modified chitosan hydrogels as a matrix for adsorption of metal ions, synthesis and characterization

Environment friendly modified chitosan hydrogels for metal ions absorption from aqueous systems were designed using simple technology. Chitosan was modified with [N,N′-bi-α-azidosuccinimide and N-phthalimido-α-azide succinimide] under different reaction conditions to prepare new hydrogels with high metal ion absorption efficiency. The hydrogels were characterized by FTIR, thermal stability, crystallography, solubility and swelling capacity. Promising results were obtained from this preliminary study to evaluate the efficiency of the new hydrogels to uptake copper and cobalt ions from aqueous systems.