71 resultados para Peripheral elimination


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Secondary or late graft failure has been defined as the development of inadequate marrow function after initial engraftment has been achieved. We describe a case of profound marrow aplasia occurring 13 years after sibling allogeneic bone marrow transplantation for chronic myeloid leukaemia (CML) in first chronic phase. Although the patient remained a complete donor chimera, thereby suggesting that an unselected infusion of donor peripheral blood stem cells (PBSC) or bone marrow might be indicated, the newly acquired aplasia was thought to be immune in aetiology and some immunosuppression was therefore considered appropriate. Rapid haematological recovery was achieved after the infusion of unselected PBSC from the original donor following conditioning with anti-thymocyte globulin (ATG).

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Ex vivo T cell depletion of allogeneic grafts is associated with a high (up to 80%) rate of mixed chimerism (MC) posttransplantation. The number of transplanted progenitor cells is an important factor in achieving complete donor chimerism in the T cell depletion setting. Use of granulocyte colony-stimulating factor (G-CSF) peripheral blood allografts allows the administration of large numbers of CD34+ cells. We studied the chimeric status of 13 patients who received allogeneic CD34+-selected peripheral blood progenitor cell transplants (allo-PBPCTs/CD34+) from HLA-identical sibling donors. Patients were conditioned with cyclophosphamide (120 mg/kg) and total-body irradiation (13 Gy in four fractions). Apheresis products were T cell-depleted by the immunoadsorption avidin-biotin method. The median number of CD34+ and CD3+ cells infused was 2.8x10(6)/kg (range 1.9-8.6x10(6)/kg) and 0.4x10(6)/kg (range 0.3-1x10(6)/kg), respectively. Molecular analysis of the engraftment was performed using polymerase chain reaction (PCR) amplification of highly polymorphic short tandem repeat (PCR-STR) sequences in peripheral blood samples. MC was detected in two (15%) of 13 patients. These two patients relapsed at 8 and 10 months after transplant, respectively. The remaining 11 patients showed complete donor chimerism and were in clinical remission after a maximum follow-up period of 24 months (range 6-24 months). These results were compared with those obtained in 10 patients who were treated with T cell-depleted bone marrow transplantation by means of elutriation and who received the same conditioning treatment and similar amounts of CD3+ cells (median 0.45x10(6)/kg; not significant) but a lower number of CD34+ cells (median 0.8x10(6)/kg; p = 0.001). MC was documented in six of 10 patients (60%), which was significantly higher than in the allo-PBPCT/CD34+ group (p = 0.04). We conclude that a high frequency of complete donor chimerism is achieved in patients receiving allo-PBPCT/CD34+ and that this is most likely due to the high number of progenitor cells administered.

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This chapter covers the indications, contraindications, techniques, outcomes, and complications of LPI. Its role is well defined in most of the areas, but no conclusion can be drawn at present regarding prophylactic use for glaucoma suspects. More studies are needed to define its safety and efficacy. Overall, LPI is a relatively safe procedure and the majority of complications can be avoided if it is performed properly.

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OBJECTIVE: To assess the impact of laser peripheral iridotomy (LPI) on forward-scatter of light and subjective visual symptoms and to identify LPI parameters influencing these phenomena. DESIGN: Cohort study derived from a randomized trial, using an external control group. PARTICIPANTS: Chinese subjects initially aged 50 or older and 70 years or younger with bilateral narrow angles undergoing LPI in 1 eye selected at random, and age- and gender-matched controls. METHODS: Eighteen months after laser, LPI-treated subjects underwent digital iris photography and photogrammetry to characterize the size and location of the LPI, Lens Opacity Classification System III cataract grading, and measurement of retinal straylight (C-Quant; OCULUS, Wetzlar, Germany) in the treated and untreated eyes and completed a visual symptoms questionnaire. Controls answered the questionnaire and underwent straylight measurement and (in a random one-sixth sample) cataract grading. MAIN OUTCOME MEASURES: Retinal straylight levels and subjective visual symptoms. RESULTS: Among 230 LPI-treated subjects (121 [58.8%] with LPI totally covered by the lid, 43 [19.8%] with LPI partly covered by the lid, 53 [24.4%] with LPI uncovered by the lid), 217 (94.3%) completed all testing, as did 250 (93.3%) of 268 controls. Age, gender, and prevalence of visual symptoms did not differ between treated subjects and controls, although nuclear (P<0.01) and cortical (P = 0.03) cataract were less common among controls. Neither presenting visual acuity nor straylight score differed between the treated and untreated eyes among all treated persons, nor among those (n = 96) with LPI partially or totally uncovered. Prevalence of subjective glare did not differ significantly between participants with totally covered LPI (6.61%; 95% confidence interval [CI], 3.39%-12.5%), partially covered LPI (11.6%; 95% CI, 5.07%-24.5%), or totally uncovered LPI (9.43%; 95% CI, 4.10%-10.3%). In regression models, only worse cortical cataract grade (P = 0.01) was associated significantly with straylight score, and no predictors were associated with subjective glare. None of the LPI size or location parameters were associated with straylight or subjective symptoms. CONCLUSIONS: These results suggests that LPI is safe regarding measures of straylight and visual symptoms. This randomized design provides strong evidence that treatment programs for narrow angles would be unlikely to result in important medium-term visual disability.

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PURPOSE: Subjects with significant peripheral field loss (PFL) self report difficulty in street crossing. In this study, we compared the traffic gap judgment ability of fully sighted and PFL subjects to determine whether accuracy in identifying crossable gaps was adversely affected because of field loss. Moreover, we explored the contribution of visual and nonvisual factors to traffic gap judgment ability. METHODS: Eight subjects with significant PFL as a result of advanced retinitis pigmentosa or glaucoma with binocular visual field <20 degrees and five age-matched normals (NV) were recruited. All subjects were required to judge when they perceived it was safe to cross at a 2-way 4-lane street while they stood on the curb. Eye movements were recorded by an eye tracker as the subjects performed the decision task. Movies of the eye-on-scene were made offline and fixation patterns were classified into either relevant or irrelevant. Subjects' street-crossing behavior, habitual approach to street crossing, and perceived difficulties were assessed. RESULTS: Compared with normal vision (NV) subjects, the PFL subjects identified 12% fewer crossable gaps while making 23% more errors by identifying a gap as crossable when it was too short (p < 0.05). The differences in traffic gap judgment ability of the PFL subjects might be explained by the significantly smaller fixation area (p = 0.006) and fewer fixations distributed to the relevant tasks (p = 0.001). The subjects' habitual approach to street crossing and perceived difficulties in street crossing (r > 0.60) were significantly correlated with traffic gap judgment performance. CONCLUSIONS: As a consequence of significant field loss, limited visual information about the traffic environment can be acquired, resulting in significantly reduced performance in judging safe crossable gaps. This poor traffic gap judgment ability in the PFL subjects raises important concerns for their safety when attempting to cross the street.

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PURPOSE:

To estimate the heritability of peripheral refraction in Chinese children and adolescents.

METHODS:

The authors examined 72 monozygotic (MZ) twins and 48 dizygotic (DZ) twins aged 8 to 20 years from a population-based twin registry. Temporal and nasal peripheral refraction, each 40° from the visual axis, and axial refraction were measured using an autorefractor. Relative peripheral refractive error (RPRE) was defined as the peripheral refraction minus the axial refraction. Heritability was assessed by structural equation modeling after adjustment for age and sex.

RESULTS:

The mean and SD of temporal refraction (T(40)), nasal refraction (N(40)), RPRE-T(40), RPRE-N(40), and T(40)-N(40) asymmetry were -0.27 ± 2.0 D, 0.36 ± 2.19 D, 1.18 ± 1.39 D, 1.80 ± 1.69 D, and -0.62 ± 1.58 D, respectively. The intraclass correlations for T(40) refraction, N(40) refraction, RPRE-T(40), RPRE-N(40), and T(40)-N(40) asymmetry were 0.87, 0.83, 0.65, 0.74, and 0.58 for MZ pairs and 0.49, 0.42, 0.30, 0.41, and 0.32 for DZ pairs, respectively. A model with additive genetic and unique environmental effects was the most parsimonious, with heritability values estimated as 0.84, 0.76, 0.63, 0.70, and 0.55, respectively, for the peripheral refractive parameters.

CONCLUSIONS:

Additive genetic effects appear to explain most of the variance in peripheral refraction and relative peripheral refraction when adjusting for the effects of axial refraction.

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We present a new wrapper feature selection algorithm for human detection. This algorithm is a hybrid featureselection approach combining the benefits of filter and wrapper methods. It allows the selection of an optimalfeature vector that well represents the shapes of the subjects in the images. In detail, the proposed featureselection algorithm adopts the k-fold subsampling and sequential backward elimination approach, while thestandard linear support vector machine (SVM) is used as the classifier for human detection. We apply theproposed algorithm to the publicly accessible INRIA and ETH pedestrian full image datasets with the PASCALVOC evaluation criteria. Compared to other state of the arts algorithms, our feature selection based approachcan improve the detection speed of the SVM classifier by over 50% with up to 2% better detection accuracy.Our algorithm also outperforms the equivalent systems introduced in the deformable part model approach witharound 9% improvement in the detection accuracy

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Contaminating tumour cells in apheresis products have proved to influence the outcome of patients with multiple myeloma (MM) undergoing autologous stem cell transplantation (APBSCT). The gene scanning of clonally rearranged VDJ segments of the heavy chain immunoglobulin gene (VDJH) is a reproducible and easy to perform technique that can be optimised for clinical laboratories. We used it to analyse the aphereses of 27 MM patients undergoing APBSCT with clonally detectable VDJH segments, and 14 of them yielded monoclonal peaks in at least one apheresis product. The presence of positive results was not related to any pre-transplant characteristics, except the age at diagnosis (lower in patients with negative products, P = 0.04). Moreover, a better pre-transplant response trended to associate with a negative result (P = 0.069). Patients with clonally free products were more likely to obtain a better response to transplant (complete remission, 54% vs 28%; >90% reduction in the M-component, 93% vs 43% P = 0.028). In addition, patients transplanted with polyclonal products had longer progression-free survival, (39 vs 19 months, P = 0.037) and overall survival (81% vs 28% at 5 years, P = 0.045) than those transplanted with monoclonal apheresis. In summary, the gene scanning of apheresis products is a useful and clinically relevant technique in MM transplanted patients.

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In the present paper, we report on the use of the heteroduplex PCR technique to detect the presence of clonally rearranged VDJ segments of the heavy chain immunoglobulin gene (VDJH) in the apheresis products of patients with multiple myeloma (MM) undergoing autologous peripheral blood stem cell (APBSC) transplantation. Twenty-three out of 31 MM patients undergoing APBSC transplantation with VDJH segments clonally rearranged detected at diagnosis were included in the study. Samples of the apheresis products were PCR amplified using JH and VH (FRIII and FRII) consensus primers and subsequently analyzed with the heteroduplex technique, and compared with those obtained at diagnosis. 52% of cases yielded positive results (presence of clonally rearranged VDJH segments in at least one apheresis). The presence of positive results in the apheresis products was not related to any pretransplant characteristics with the exception of response status at transplant. Thus, while no one patient with positive apheresis products was in complete remission (CR), negative immunofixation, before the transplant, five cases (46%) with negative apheresis were already in CR at transplant (P = 0.01). The remaining six cases with heteroduplex PCR negative apheresis were in partial remission before transplant. Patients with clonally free products were more likely to obtain CR following transplant (64% vs 17%, P= 0.02) and a longer progression-free survival, (40 months in patients transplanted with polyclonal products vs 20 with monoclonal ones, P = 0.03). These results were consistent when the overall survival was considered, since it was better in those patients with negative apheresis than it was in those with positive (83% vs 36% at 5 years from diagnosis, P= 0.01). These findings indicate that the presence of clonality rearranged VDJH segments is related to the response and outcome in MM transplanted patients.

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A new synthesis of (+)-brefeldin A is reported via Padwa allenylsulfone [3+2]-cycloadditive elimination. Cycloadduct 13 was initially elaborated into iodide
27, which, following treatment with Zn, gave aldehyde 28 whose C(9) stereocenter was epimerized. Further elaboration into enoate 38 and Julia−Kocienski olefination with 5 subsequently afforded 39, which was deprotected at C(1) and O(15). Yamaguchi macrolactonization of the seco-acid thereafter afforded a macrocycle that underwent O-desilylation and inversion at C(4) to give (+)-brefeldin A following deprotection