Boston Children's Hospital

About: Boston Children's Hospital is a healthcare organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 165409 authors who have published 215589 publications receiving 6885627 citations.

Cell origin and differentiation in the repair of full-thickness defects of articular cartilage.

Abstract: The origin and differentiation of cells in the repair of three-millimeter-diameter, cylindrical, full-thickness drilled defects of articular cartilage were studied histologically in New Zealand White rabbits. The animals were allowed to move freely after the operation. Three hundred and sixty-four individual defects from 122 animals were examined as long as forty-eight weeks postoperatively. In the first few days, fibrinous arcades were established across the defect, from surface edge to surface edge, and this served to orient mesenchymal cell ingrowth along the long axes. The first evidence of synthesis of a cartilage extracellular matrix, as defined by safranin-O staining, appeared at ten days. At two weeks, cartilage was present immediately beneath the surface of collagenous tissue that was rich in flattened fibrocartilaginous cells in virtually all specimens. At three weeks, the sites of almost all of the defects had a well demarcated layer of cartilage containing chondrocytes. An essentially complete repopulation of the defects occurred at six, eight, ten, and twelve weeks, with progressive differentiation of cells to chondroblasts, chondrocytes, and osteoblasts and synthesis of cartilage and bone matrices in their appropriate locations. At twenty-four weeks, both the tidemark and the compact lamellar subchondral bone plate had been re-established. The cancellous woven bone that had formed initially in the depths of the defect was replaced by lamellar, coarse cancellous bone. Autoradiography after labeling with 3H-thymidine and 3H-cytidine demonstrated that chondrocytes from the residual adjacent articular cartilage did not participate in the repopulation of the defect. The repair was mediated wholly by the proliferation and differentiation of mesenchymal cells of the marrow. Intra-articular injections of 3H-thymidine seven days after the operation clearly labeled this mesenchymal cell pool. The label, initially taken up by undifferentiated mesenchymal cells, progressively appeared in fibroblasts, osteoblasts, articular chondroblasts, and chondrocytes, indicating their origin from the primitive mesenchymal cells of the marrow. Early traces of degeneration of the cartilage matrix were seen in many defects at twelve to twenty weeks, with the prevalence and intensity of the degeneration increasing at twenty-four, thirty-six, and forty-eight weeks. Polarized light microscopy demonstrated failure of the newly synthesized repair matrix to become adherent to, and integrated with, the cartilage immediately adjacent to the drill-hole, even when light microscopy had shown apparent continuity of the tissue. In many instances, a clear gap was seen between repair and residual cartilage.(ABSTRACT TRUNCATED AT 400 WORDS)

Seventh INTERMACS annual report: 15,000 patients and counting

Abstract: The seventh annual report of the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) summarizes the first 9 years of patient enrollment. The Registry includes >15,000 patients from 158 participating hospitals. Trends in device strategy, patient profile at implant and survival are presented. Risk factors for mortality with continuous-flow pumps are updated, and the major causes/modes of death are presented. The adverse event burden is compared between eras, and health-related quality of life is reviewed. A detailed analysis of outcomes after mechanical circulatory support for ambulatory heart failure is presented. Recent summary data from PediMACS and MedaMACS is included. With the current continuous-flow devices, survival at 1 and 2 years is 80% and 70%, respectively.

Prevalence of Type 1 and Type 2 Diabetes Among Children and Adolescents From 2001 to 2009

Abstract: RESULTS In 2001, 4958 of 3.3 million youth were diagnosed with type 1 diabetes for a prevalence of 1.48 per 1000 (95% CI, 1.44-1.52). In 2009, 6666 of 3.4 million youth were diagnosed with type 1 diabetes for a prevalence of 1.93 per 1000 (95% CI, 1.88-1.97). In 2009, the highest prevalence of type 1 diabetes was 2.55 per 1000 among white youth (95% CI, 2.48-2.62) and the lowest was 0.35 per 1000 in American Indian youth (95% CI, 0.26-0.47) and type 1 diabetes increased between 2001 and 2009 in all sex, age, and race/ethnic subgroups except for those with the lowest prevalence (age 0-4 years and American Indians). Adjusted for completeness of ascertainment, there was a 21.1% (95% CI, 15.6%-27.0%) increase in type 1 diabetes over 8 years. In 2001, 588 of 1.7 million youth were diagnosed with type 2 diabetes for a prevalence of 0.34 per 1000 (95% CI, 0.31-0.37). In 2009, 819 of 1.8 million were diagnosed with type 2 diabetes for a prevalence of 0.46 per 1000 (95% CI, 0.43-0.49). In 2009, the prevalence of type 2 diabetes was 1.20 per 1000 among American Indian youth (95% CI, 0.96-1.51); 1.06 per 1000 among black youth (95% CI, 0.93-1.22); 0.79 per 1000 among Hispanic youth (95% CI, 0.70-0.88); and 0.17 per 1000 among white youth (95% CI, 0.15-0.20). Significant increases occurred between 2001 and 2009 in both sexes, all age-groups, and in white, Hispanic, and black youth, with no significant changes for Asian Pacific Islanders and American Indians. Adjusted for completeness of ascertainment, there was a 30.5% (95% CI, 17.3%-45.1%) overall increase in type 2 diabetes. CONCLUSIONS AND RELEVANCE Between 2001 and 2009 in 5 areas of the United States, the prevalence of both type 1 and type 2 diabetes among children and adolescents increased. Further studies are required to determine the causes of these increases.

Exposure to Environmental Microorganisms and Childhood Asthma

Abstract: In two cross-sectional studies, we compared children living on farms with those in a reference group with respect to the prevalence of asthma and atopy and to the diversity of microbial exposure. In one study — PARSIFAL (Prevention of Allergy — Risk Factors for Sensitization in Children Related to Farming and Anthroposophic Lifestyle) — samples of mattress dust were screened for bacterial DNA with the use of single-strand conformation polymorphism (SSCP) analyses to detect environmental bacteria that cannot be measured by means of culture techniques. In the other study — GABRIELA (Multidisciplinary Study to Identify the Genetic and Environmental Causes of Asthma in the European Community [GABRIEL] Advanced Study) — samples of settled dust from children’s rooms were evaluated for bacterial and fungal taxa with the use of culture techniques. Results In both studies, children who lived on farms had lower prevalences of asthma and atopy and were exposed to a greater variety of environmental microorganisms than the children in the reference group. In turn, diversity of microbial exposure was inversely related to the risk of asthma (odds ratio for PARSIFAL, 0.62; 95% confidence interval [CI], 0.44 to 0.89; odds ratio for GABRIELA, 0.86; 95% CI, 0.75 to 0.99). In addition, the presence of certain more circumscribed exposures was also inversely related to the risk of asthma; this included exposure to species in the fungal taxon eurotium (adjusted odds ratio, 0.37; 95% CI, 0.18 to 0.76) and to a variety of bacterial species, including Listeria monocytogenes, bacillus species, corynebacterium species, and others (adjusted odds ratio, 0.57; 95% CI, 0.38 to 0.86). Conclusions Children living on farms were exposed to a wider range of microbes than were children in the reference group, and this exposure explains a substantial fraction of the inverse relation between asthma and growing up on a farm. (Funded by the Deutsche Forschungsgemeinschaft and the European Commission.)