Control of GVHD by regulatory T cells depends on TNF produced by T cells and TNFR2 expressed by regulatory T cells.

Therapeutic CD4(+)Foxp3(+) natural regulatory T cells (Tregs) can control experimental graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HCT) by suppressing conventional T cells (Tconvs). Treg-based therapies are currently tested in clinical trials with promising preliminary results in allo-HCT. Here, we hypothesized that as Tregs are capable of modulating Tconv response, it is likely that the inflammatory environment and particularly donor T cells are also capable of influencing Treg function. Indeed, previous findings in autoimmune diabetes revealed a feedback mechanism that renders Tconvs able to stimulate Tregs by a mechanism that was partially dependent on tumor necrosis factor (TNF). We tested this phenomenon during alloimmune response in our previously described model of GVHD protection using antigen specific Tregs. Using different experimental approaches, we observed that control of GVHD by Tregs was fully abolished by blocking TNF receptor type 2 (TNFR2) or by using TNF-deficient donor T cells or TNFR2-deficient Tregs. Thus, our results show that Tconvs exert a powerful modulatory activity on therapeutic Tregs and clearly demonstrate that the sole defect of TNF production by donor T cells was sufficient to completely abolish the Treg suppressive effect in GVHD. Importantly, our findings expand the understanding of one of the central components of Treg action, the inflammatory context, and support that targeting TNF/TNFR2 interaction represents an opportunity to efficiently modulate alloreactivity in allo-HCT to either exacerbate it for a powerful antileukemic effect or reduce it to control GVHD.

Antifungal and Antibacterial Activities of Crude Extracts of Four Phellinus Species and Coltricia fragilissima (Agaricomycetes) from Cameroon and Democratic Republic of Congo.

Antifungal and antibacterial activities of crude extracts of Phellinus extensus, Ph. gilvus, Ph. pachyphloeus, Ph. senex and Coltricia fragilissima were investigated on eleven species of bacteria and three fungal human pathogens. The minimum inhibitory concentration (MIC) was determined by the microdilution method. The results of this study reveal that for the eleven strains of bacteria tested, including Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, S. epidermidis, Enterobacter cloacae, Klebsiella aerogenes, Mycobacterium smegmatis, Proteus vulgaris, Proteus mirabilis and Escherichia choli, the MIC of the crude extract of the four species of Phellinus as well as that of C. fragilissima ranged from 3.13 to 12.50 mg/mL. For the three strains of fungi tested including Candida albicans, Aspergillus ochraceus and A. fumigetus, the MIC of the crude extracts of the same four species of Phellinus as well as that of C. fragilissima ranged from 0.39 to 3.13 mg/mL. These data reveal that the antimicrobial activity of crude extracts of Phellinus and Coltricia species is stronger on pathogenic fungi than on bacteria. C. fragilissima being of the same family as Phellinus and having recorded the values of MIC eminently close to those of the latter may potentially be used for medicinal purposes like the investigated Phellinus species. Being highly represented in the sub-Saharan regions and owing to the above-mentioned results, these species could now be considered as part of the non-exhaustive list of medicinal mushrooms in these regions and may constitute a new source of natural molecules that may be more active than synthetic products against certain fungal and bacterial borne diseases.

Comparative Assessment of Antifungal and Antibacterial Activities of Crude Extracts of the King Tuber Culinary-Medicinal Mushroom, Pleurotus tuber-regium (Agaricomycetes) from Cameroon.

Antifungal and antibacterial activities of crude extracts of carpophore compared with those of sclerotium of Pleurotus tuber-regium were investigated on 11 species of bacterial and 3 fungal human pathogens. The minimal inhibitory concentration (MIC) of carpophore extract was recorded to be 12.5 mg/mL on Bacillus subtilis, Enterococcus faecalis, Staphylococcus epidermidis, Escherichia cloacae, Proteus mirabilis, P. vulgaris, Klebsiella oxytoca, and K. aerogenes and 6.25 mg/mL on Staphylococcus aureus, Escherichia coli, and Mycobacterium smegmatis as well as on all three species of fungal pathogens including Candida albicans, Aspergillus fumigatus, and A. ochraceus. In comparison, the MIC of sclerotium was recorded to be 12.5 mg/mL on Bacillus subtilis and Klebsiella aerogenes; 6.25 mg/mL on Enterococcus faecalis, Staphylococcus aureus, S. epidermidis, Enterobacter cloacae, E. coli, Mycobacterium smegmatis, Proteus mirabilis, P. vulgaris, and Klebsiella oxytoca; and 3.13 mg/mL on the three fungal pathogens. Based on the abovementioned figures, it appears that strains of pathogenic fungi tested are much more sensitive to crude extracts than the abovementioned bacteria. In fact, antimicrobial activities of crude extracts of P. tuber-regium, no matter whether it is that of the carpophore or its sclerotium, are in general stronger on human pathogenic fungi than bacteria. These figures also demonstrate that crude extracts of sclerotium show a higher antimicrobial activity than that of carpophore. Carpophores and sclerotia of P. tuber-regium could therefore constitute a source of new molecules potentially more efficient than synthetic products against some human pathogenic fungi and bacteria.

Novel mouse model of monocular amaurosis fugax.

BACKGROUND AND PURPOSE: Retinal ischemia is a major cause of visual impairment and is associated with a high risk of subsequent ischemic stroke. The retina and its projections are easily accessible for experimental procedures and functional evaluation. We created and characterized a mouse model of global and transient retinal ischemia and provide a comprehensive chronologic profile of some genes that display altered expression during ischemia. METHODS: Ischemia and reperfusion were assessed by observing flat-mounted retinas after systemic fluorescein injection. The temporal pattern of gene expression modulation was evaluated by quantitative reverse transcription-polymerase chain reaction from the occurrence of unilateral 30-minute pterygopalatine artery occlusion until 4 weeks after reperfusion. Electroretinograms evaluated functional sequelae 4 weeks after the ischemic episode and were correlated with histologic lesions. RESULTS: This model is the first to reproduce the features of transient monocular amaurosis fugax resulting from ophthalmic artery occlusion. The histologic structure was roughly conserved, but functional lesions affected ganglion cells, inner nuclear layer cells, and photoreceptor cells. We observed an early and strong upregulation of c-fos, c-jun, Cox-2, Hsp70, and Gadd34 gene expression and a late decrease in Hsp70 transcript levels. CONCLUSIONS: A murine model of transient retinal ischemia was successfully developed that exhibited the characteristic upregulation of immediate-early genes and persistent functional deficits. The model should prove useful for investigating mechanisms of injury in genetically altered mice and for testing novel neuroprotective drugs.

The Henri Mondor Procedure of Morbidity and Mortality Review Meetings: Prospective Registration of Clinical, Dosimetric, and Individual Radiosensitivity Data of Patients With Severe Radiation Toxicity.

PURPOSE: After radiation therapy (RT), various radiation-induced toxicities can develop in about one-fourth of patients. An international interest in using morbidity and mortality rates to monitor the quality of care and integrate morbidity and mortality review (MMR) meetings into organizations' governance processes has arisen. We report the first results of patients included in our MMR procedure that included biological assays for individual intrinsic radiosensitivity (IIRS). METHODS AND MATERIALS: Twenty-three patients were prospectively included in the MMR database. Twenty-two were evaluable for IIRS. Prostate (n=10) and breast (n=8) cancers were the most frequent disease types. The total dose delivered, determined according to the type of disease, ranged from 30 to 74 Gy. Our MMR procedure requires strict criteria: patients with unresolved toxicity of grade 3 or higher with availability of clinical (photographic) data, IIRS results obtained from skin biopsy assays, treatment modalities, and follow-up data. The RT technique and dosimetry were reviewed. RESULTS: Our prospective registration of toxicities showed mainly rectitis, occurring in 7 cases, and skin toxicities, occurring in 9. Of the 7 patients with rectitis, 5 received 66 Gy of post-prostatectomy RT with V50 (rectum volume receiving 50 Gy) ranging from 45% to 75% and a mean maximal dose of 66.5 Gy. For dermatitis and cystitis, the mean maximal doses were in the range of classical constraints without any overdosage or dose heterogeneity. No errors were found in the review of treatment planning and positioning. Conversely, all the patients were considered biologically as radiosensitive with genomic instability and ATM (ataxia telangiectasia mutated)-dependent DNA double-strand break repair impairments. CONCLUSIONS: The MMR review of files allowed clear answers for patients on the relationship between clinical events and their IIRS. Our procedure has allowed education of all our staff to monitor, identify, and document clinical, physical, and biological aspects of radiation-induced toxicities. Thus we recommend the introduction of the MMR procedure in RT departments.

Nutrient content of some mushroom species of the genus Termitomyces consumed in Cameroon.

The nutrient content (water, lipids, proteins, ashes, crude fibres) of six mushroom species (Termitomyces le Testui, T. aurantiacus, T. schimperi, T. mammformis, T. mboudaeïna Mossebo sp. nov., and T. subcypeatus forme bisporus sp. nov.) of the genus Termitomyces from Cameroon was determined. These mushrooms have a high water content (83.3-94.3 g/100 g wet matter) and contain more lipids than species from temperate countries (2.5-5.4 g/100 g dry weight), with high proportions of polyunsaturated fatty acids (45.1-65.1% of total fatty acid methyl esters) and remarkable proportions of crude fibres (17.5-24.7 g/ 100 g dry weight). Their protein content varied between 15.1 and19.1 g/100 g dry weight and ash content between 5.2 and 14.4. The species T. mammiformis was found particularly rich in minerals with 14.4 g ash/ 100 g dry material, that is up to 2.4 g/100 g fresh weight.