34 resultados para STEM ANATOMY
Resumo:
Animal models of autoimmune disease and case reports of patients with these diseases who have been involved in bone marrow transplants have provided important data implicating the haemopoietic stem cell in rheumatic disease pathogenesis. Animal and human examples exist for both cure and transfer of rheumatoid arthritis, systemic lupus erythematosus (SLE) and other organ-specific diseases using allogeneic haemopoietic stem cell transplantation. This would suggest that the stem cell in these diseases is abnormal and could be cured by replacement of a normal stem cell although more in vitro data are required in this area. Given the morbidity and increased mortality in some patients with severe autoimmune diseases and the increasing safety of autologous haemopoietic stem cell transplantation (HSCT), pilot studies have been conducted using HSCT in rheumatic diseases. It is still unclear whether an autologous graft will cure these diseases but significant remissions have been obtained which have provided important data for the design of randomized trials of HSCT versus more conventional therapy. Several trials are now open to accrual under the auspices of the European Bone Marrow Transplant Group/European League Against Rheumatism (EBMT/EULAR) registry. Future clinical and laboratory research will need to document the abnormalities of the stem cell of a rheumatic patient because new therapies based on gene therapy or stem cell differentiation could be apllied to these diseases. With increasing safety of allogeneic HSCT it is not unreasonable to predict cure of some rheumatic diseases in the near future.
Resumo:
The composition of the Pyrgulidae and its relationships to other member families of the caenogastropod superfamily Rissooidea are examined after a consideration of new anatomical (including gross anatomy, sperm ultrastructure), conchological (including protoconch features), ecological, biogeographical and palaeontological data and a re-evaluation of existing literature. Pyrgulidae can be distinguished from hydrobiids unequivocally only with the aid of the radula. Sperm ultrastructural features suggest a very close relationship between the Pyrgulidae, the Hydrobiidae and the Bithyniidae (in fact no family-diagnostic sperm characters can be found to separate these three taxa). Based upon neontological and fossil evidence it is likely that pyrgulids represent a Miocene offshoot from a paratethyal hydrobiid lineage. Pyrgulids may also represent the stock from which the baicaliids arose, in which case the Pyrgulidae must be considered a paraphyletic group. The huge biogeographic gap between the Caspian Sea and Lake Baikal is to some extent bridged by the finding of a Neogene pyrgulid from the Altai Mountains. An alternative scenario for the origin of baicaliids is presented.
Resumo:
Large (>1600 mum), ingestively masticated particles of bermuda grass (Cynodon dactylon L. Pers.) leaf and stem labelled with Yb-169 and Ce-144 respectively were inserted into the rumen digesta raft of heifers grazing bermuda grass. The concentration of markers in digesta sampled from the raft and ventral rumen were monitored at regular intervals over approximately 144 h. The data from the two sampling sites were simultaneously fitted to two pool (raft and ventral rumen-reticulum) models with either reversible or sequential flow between the two pools. The sequential flow model fitted the data equally as well as the reversible flow model but the reversible flow model was used because of its greater application. The reversible flow model, hereafter called the raft model, had the following features: a relatively slow age-dependent transfer rate from the raft (means for a gamma 2 distributed rate parameter for leaf 0.0740 v. stem 0.0478 h(-1)), a very slow first order reversible flow from the ventral rumen to the raft (mean for leaf and stem 0.010 h(-1)) and a very rapid first order exit from the ventral rumen (mean of leaf and stem 0.44 h(-1)). The raft was calculated to occupy approximately 0.82 total rumen DM of the raft and ventral rumen pools. Fitting a sequential two pool model or a single exponential model individually to values from each of the two sampling sites yielded similar parameter values for both sites and faster rate parameters for leaf as compared with stem, in agreement with the raft model. These results were interpreted as indicating that the raft forms a large relatively inert pool within the rumen. Particles generated within the raft have difficulty escaping but once into the ventral rumen pool they escape quickly with a low probability of return to the raft. It was concluded that the raft model gave a good interpretation of the data and emphasized escape from and movement within the raft as important components of the residence time of leaf and stem particles within the rumen digesta of cattle.
Resumo:
Prospective studies have shown rapid engraftment using granulocyte-colony-stimulating factor-mobilized peripheral blood stem cells (G-PBSCs) for allogeneic transplantation, though the risks for graft-versus-host disease (GVHD) may be increased. It was hypothesized that the use of G-CSF to prime bone marrow (GBM) would allow rapid engraftment without increased risk for GVHD compared with G-PBSC. Patients were randomized to receive G-BM or G-PBSCs for allogeneic stem cell transplantation. The study was designed (beta < .8) to detect a difference in the incidence of chronic GVHD of 33% ( < .05). The plan was to recruit 100 patients and to conduct an interim analysis when the 6-month follow-up point was reached for the first 50 patients. Fifty-seven consecutive patients were recruited (G-BM, n = 28; G-PBSC, n = 29). Patients in the G-PBSC group received 3-fold more CD34(+) and 9-fold more CD3(+) cells. Median times to neutrophil (G-BM, 16 days; G-PBSC, 14 days; P < .1) and platelet engraftment (G-BM, 14 days; G-PBSC, 12 days; P < .1) were similar. The use of G-PBSC was associated with steroid refractory acute GVHD (G-BM, 0%; G-PBSC, 32%; P < .001), chronic GVHD (G-BM, 22%; G-PBSC, 80%; P < .02), and prolonged requirement for immunosuppressive therapy (G-BM, 173 days; G-PBSC, 680 days; P < .009). Survival was similar for the 2 groups. Compared with G-PBSC the use of G-BM resulted in comparable engraftment, reduced severity of acute GVHD, and less subsequent chronic GVHD. (Blood. 2001;98:3186-3191) (C) 2001 by The American Society of Hematology.
Resumo:
The development of a new product or a new process, if adopted by the market, may generate a number of economic processes including secondary innovations to promote the exploitation of the new discovery. Such technological advances may also promote new industrial ventures which may exist over many decades, enhancing economic development. The history of the adoption of the cyanide process for the extraction of gold from its ores exemplifies such developments. One outcome was the formation of an international cyanide cartel.
Resumo:
Objective. The aim of this study was to determine the function of primitive hematopoietic stem cells (PHSC) at phases G(0) and G(1) of the cell cycle. Materials and Methods. A combination of supravital dyes rhodamine123 (Rh), Hoechst33342 (Ho), and pyronin (PY) was used to isolate the G(0) and G(1) subsets of PHSC. A competitive repopulation assay was used to evaluate their in vivo function. Results. We confirmed that the Rh(lo)Lin(-)Kit(+)Sca-1(+) PHSC were relatively quiescent when compared with the more mature Rh(hi)Lin(-)Kit(+)Sca-1 HSC and Rh(hi)Lin(-)Kit(+)Sca-1(-) progenitors. In addition, cells with Rh(lo)Lin(-)Kit(+)Sca-1(+), Rh(lo)Ho(lo)Lin(-)Sca-1(+), or Rh(lo)Ho(sp)Lin(-)Sca-1(+) phenotypes identified the same cell population. We further subfractionated the Rh(lo)Ho(lo/sp)Lin(-)Sca-1(+) PHSC using PY into PYlo and PYhi subsets. Limiting dilution analysis revealed that the frequency of long-term in vivo competitive repopulating units (CRU) of the (PYRhHolo/sp)-Rh-lo-Ho-lo PHSC was 1 in 10 cells, whereas there was at least a three-fold lower frequency in those isolated at the G(1) phase (PYhi) We found a dose-dependent PY-mediated cytotoxicity that at moderate concentration affected most of the murine hematopoietic compartment but spared the early HSC compartment. Conclusion. Our data confirm that the HSC compartment is hierarchically ordered on the basis of quiescence and further extend this concept to PY-mediated cytotoxicity. PY supravital dye can be used to reveal functional heterogeneity within the (RhHolosp)-Ho-lo PHSC population but is of limited use in dissecting the relatively more mature hematopoietic stem/progenitor cell population. (C) 2001 International Society for Experimental Hematology. Published by Elsevier Science Inc.
Resumo:
Selected isolates of Cladosporium tenuissimum were tested for their ability to inhibit in vitro aeciospore germination of the two-needle pine stem rusts Cronartium flaccidum and Peridermium pini and to suppress disease development in planta. The antagonistic fungus displayed a number of disease-suppressive mechanisms. Aeciospore germination on water agar slides was reduced at 12, 18, and 24 h when a conidial suspension (1.5 x 10(7) conidia per ml) of the Cladosporium tenuissimum isolates was added. When the aeciospores were incubated in same-strength conidial suspensions for 1, 11, 21, and 31 days, viability was reduced at 20 and 4 degreesC. Light and scanning electron microscopy showed that rust spores were directly parasitized by Cladosporium tenuissimum and that the antagonist had evolved several strategies to breach the spore wail and gain access to the underlying tissues. Penetration occurred with or without appressoria. The hyperparasite exerted a mechanical force to destroy the spore structures (spinules, cell wall) by direct contact, penetrated the aeciospores and subsequently proliferated within them. However, an enzymatic action could also be involved. This was shown by the dissolution of the host tell wall that comes in contact with the mycelium of the mycoparasite, by the lack of indentation in the host wall at the contact site, and by the minimal swelling at the infecting hyphal tip. Culture filtrates of the hyperparasite inhibited germination of rust propagules. A compound purified from the filtrates was characterized by chemical and spectroscopic analysis as cladosporol, a known beta -1,3-glucan biosynthesis inhibitor. Conidia of Cladosporium tenuissimum reduced rust development on new infected pine seedlings over 2 years under greenhouse conditions. Because the fungus is an aggressive mycoparasite, produces fungicidal metabolites, and can survive and multiply in forest ecosystems without rusts, it seems a promising agent for the biological control of pine stem rusts in Europe.
Resumo:
The in vitro efficacy of several fungicides against Botryosphaeria dothidea (syn. Dothiorella dominicana) and their in vivo efficacy in controlling mango cv. Kensington Pride stem-end rot on partial-pressure infiltration v. dip treatment of green mature fruit was evaluated. In vitro sensitivity of B. dothidea to Benlate (benomyl), Sportak (prochloraz) and Scala (pyrimethanil) at 10 dilutions of the manufacturer's recommended rate was first determined at typical cold (13degreesC) and shelf (23degreesC) storage temperatures. The effectiveness of partial-pressure infiltration and conventional hot (52degreesC) or cold (26degreesC) dipping of fruit after harvest was then evaluated using the commercially recommended rate for each fungicide. In vitro, Benlate and Sportak prevented the growth of B. dothidea at both storage temperatures and at all concentrations, while Scala partially controlled growth of the pathogen. Benlate was the most effective fungicide for stem-end rot control. Sportak and Scala resulted in stem-end rot control when applied by partial-pressure infiltration, but not as dips. Partial-pressure infiltration holds promise for enhancing the efficacy of otherwise less effective but alternative fungicides for control of stem-end rot diseases.
Resumo:
Survival of bone marrow transplant recipients requiting mechanical ventilation is poor but improving. This study reports a retrospective audit of all haematopoietic stem cell transplant (HSCT) recipients requiring mechanical ventilation at an Australian institution over a period spanning 11 years from 1988 to 1998. Recipients of autologous transplants are significantly less likely to require mechanical ventilation than recipients of allogeneic transplants. Of 50 patients requiring mechanical ventilation, 28% survived to discharge from the intensive care unit, 20% to 30 days post-ventilation, 18% to discharge from hospital and 12% to six months post-ventilation. Risk factors for mortality in the HSCT recipient requiting mechanical ventilation include renal, hepatic and cardiovascular insufficiency and greater severity of illness. Mechanical ventilation of HSCT recipients should not be regarded as futile therapy.
Resumo:
This is the first documented study of the anatomical details of the contents of the normal koala orbit, excluding the bulbus oculi. Baseline data were established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The anatomy of the orbital contents of the koala were examined and described from animals that presented dead or were euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification. Polymethyl methacrylate (PMMA) casts of the nasolacrimal system and the vascular supply of the orbit were also made in order to study these systems. The superficial lymphatic drainage of the conjunctival tissues was studied by subcutaneous injection of Evan's Blue into the palpebral conjunctiva of a freshly deceased animal, and by Microfil casts of the efferent lymphatics. In general, the orbital contents of the koala are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials.
Resumo:
This is the first documented study of the anatomical details of the normal koala orbit. Baseline data are established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The bony anatomy of the orbit of the koala was examined and described from animals that presented dead or had been euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification, and descriptions of the orbital bones were from macerated skulls that had been boiled and cleaned, In general, the orbital bones of the koala, and their respective foramina, are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials.
Resumo:
Objective. Evidence from animal studies, case reports, and phase I studies suggests that hemopoietic stem cell transplantation (HSCT) can be effective in the treatment of rheumatoid arthritis (RA). It is unclear, however, if depletion of T cells in the stem cell product infused after high-dose chemotherapy is beneficial in prolonging responses by reducing the number of infused autoreactive T cells. This pilot multicenter, randomized trial was undertaken to obtain feasibility data on whether CD34 selection (as a form of T cell depletion) of an autologous stem cell graft is of benefit in the HSCT procedure in patients with severe, refractory RA. Methods. Thirty-three patients with severe RA who had been treated unsuccessfully with methotrexate and at least 1 other disease-modifying agent were enrolled in the trial. The patients received high-dose immunosuppressive treatment with 200 mg/kg cyclophosphamide followed by an infusion of autologous stem cells that were CD34 selected or unmanipulated. Safety, efficacy (based on American College of Rheumatology [ACR] response criteria), and time to recurrence of disease were assessed on a monthly basis for up to 12 months. Results. All patients were living at the end of the study, with no major unexpected toxicities. Overall, on an intent-to-treat basis, ACR 20% response (ACR20) was achieved in 70% of the patients. An ACR70 response was attained in 27.7% of the 18 patients who had received CD34-selected cells and 53.3% of the 15 who had received unmanipulated cells (P = 0.20). The median time to disease recurrence was 147 days in the CD34-selected cell group and 201 days in the unmanipulated cell group (P = 0.28). There was no relationship between CD4 lymphopenia and response, but 72% of rheumatoid factor (RF)-positive patients had an increase in RF titer prior to recurrence of disease. Conclusion. HSCT can be performed safely in patients with RA, and initial results indicate significant responses in patients with severe, treatment-resistant disease. Similar outcomes were observed in patients undergoing HSCT with unmanipulated cells and those receiving CD34-selected cells. Larger studies are needed to confirm these findings.