10,016 research outputs found
Neogene grabens in southernmost Illinois
National Earthquake Hazards Reduction Program Award No. 1434-HQ-97-GR-03195Ope
Neogene grabens in southernmost Illinois
U.S. Geological Survey, Department of the Interior, National Earthquake Hazards Reduction Program Award No. 1434-HQ-97-GR-03195Ope
Induction of tolerance to a murine fibrosarcoma in two zones of dosage--the involvement of suppressor cells.
Small size inocula (10(1)-10(3) cells) of cells from a syngeneic methylcholanthrene-induced fibrosarcoma (FSA) induced tolerance when injected s.c. into C3Hf mice. Mice were unable to respond to subsequent challenge with moderate, immunogenic doses of FSA. Tolerance was demonstrated in an in vivo transfer (Winn) assay and an in vitro tumour-specific TH cell assay. Low zone tolerance was associated with the presence of tumour-specific TS cells in the spleen. Moderate size inocula (10(4)-10(6) FSA cells) were immunogenic but larger cell doses (greater than 10(6)) were again tolerogenic. In the high zone, tolerance was associated with both tumour-specific TS cells and non T suppressor cells that were not tumour-specific. These results support the view that immunogenic tumours, as they grow from small cell numbers, might be able to escape host surveillance by specifically tolerizing the immune system. They also suggest that large tumour burdens can interfere with the host's immune response by inducing suppressor cells
Minimally invasive reduction and percutaneous fixation versus open reduction and internal fixation for displaced intra-articular calcaneal fractures : a systematic review of the literature
The aim of this article is to systematically identify and analyse research evidence available to compare the outcomes of minimally invasive reduction and percutaneous fixation (MIRPF) versus open reduction and internal fixation (ORIF) for displaced intra-articular calcaneal fractures.
Articles from 2000 to 2016 were searched through MEDLINE (PubMed), Cochrane Library, Embase, ScienceDirect, Scopus and ISI Web of Knowledge using Boolean logic and text words. Of the 570 articles identified initially, nine were selected including three randomized controlled trials and six retrospective comparative studies.
All nine studies had a total of 1,031 patients with 1,102 displaced intra-articular calcaneal fractures. Mean follow-up was 33 months. Of these, 602 (54.6%) were treated with MIRPF and 500 (45.4%) were treated with ORIF.
Overall incidence of wound-related complications in patients treated with MIRPF was 4.3% (0% to 13%) compared with 21.2% (11.7% to 35%) in the ORIF group
Functional outcomes were reported to be better in the minimally invasive group in all studies; however, the results did not reach statistical significance in some studies. All the studies had methodological flaws that put them at either ‘unclear’ or ‘high’ risk of bias for multiple domains.
Overall quality of the available evidence is poor in support of either surgical technique due to small sample size, flaws in study designs and high risk of bias for various elements. Individual studies have reported minimally invasive techniques to be an effective alternative with lower risk of wound complications and better functional outcomes.</ul
The effect of gold salts on tumour immunity and its stimulation by Corynebacterium Parvum.
The anti-inflammatory agent sodium aurothiomalate appears to act upon mononuclear phagocytes, inhibiting their lysosomal enzyme activity. Evidence is presented that gold salts can increase the number of lung tumour nodules that develop following intravenous injection of tumour cells and pretreatment can enhance the take of a subcutaneous tumour inoculum. In contrast, they do not affect the later growth of tumour. Gold salts can also suppress the action of systemically administered C. parvum in inhibiting the growth of subcutaneous tumours. These results are taken as supporting the evidence in favour of a fast acting nonspecific anti-tumour mechanism, probably macrophage mediated, that can be inhibited by gold salts and enhanced by C. parvum. The effect of gold salts upon other biological changes induced by C. parvum is examined, including its adjuvant action, and the results are discussed in the context of the mechanisms underlying the immunotherapeutic action of this organism
Marrow-derived stromal cell delivery on fibrin microbeads can correct radiation-induced wound-healing deficits.
Skin that is exposed to radiation has an impaired ability to heal wounds. This is especially true for whole-body irradiation, where even moderate nonlethal doses can result in wound-healing deficits. Our previous attempts to administer dermal cells locally to wounds to correct radiation-induced deficits were hampered by poor cell retention. Here we improve the outcome by using biodegradable fibrin microbeads (FMBs) to isolate a population of mesenchymal marrow-derived stromal cells (MSCs) from murine bone marrow by their specific binding to the fibrin matrix, culture them to high density in vitro, and deliver them as MSCs on FMBs at the wound site. MSCs are retained locally, proliferate in site, and assist wounds in gaining tensile strength in whole-body irradiated mice with or without additional skin-only exposure. MSC-FMBs were effective in two different mouse strains but were ineffective across a major histocompatability barrier. Remarkably, irradiated mice whose wounds were treated with MSC-FMBs showed enhanced hair regrowth, suggesting indirect effect on the correction of radiation-induced follicular damage. Further studies showed that additional wound-healing benefit could be gained by administration of granulocyte colony-stimulating factor and AMD3100. Collagen strips coated with haptides and MSCs were also highly effective in correcting radiation-induced wound-healing deficits
Pitfalls in the use of the lung colony assay to assess T-cell function in irradiated mice.
Mice depleted of T lymphocytes by thymectomy, whole-body irradiation and bone-marrow reconstitution showed a marked increase in susceptibility to the development of lung colonies after i.v. injection of cells of an immunogenic fibrosarcoma. However, a similar increase was observed in unthymectomized, irradiated and reconstituted mice that had recovered their T-cell function, as evidenced by rejection of allogeneic skin grafts. In both thymectomized and unthymectomized mice subjected to whole-body irradiation, the lung-colony-forming efficiency was high 1 day after irradiation, declined to a minimum at 7 days, and thereafter increased again, unless the animals were held in a pathogen-free environment. Reconstitution of T-cell-depleted mice with thymocytes and/or a thymic lobe graft tended to increase further, rather than reduce, lung-colony-forming efficiency. Induction of profound lymphopenia, by irradiation of the whole body except the thorax, did not significantly increase lung colony yields. These studies show that the lung colony assay is not a reliable method of assessing T-cell function in irradiated mice
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