RESUMO
Systemic rotavirus infection, such as rotavirus antigenemia, has been found in immunocompetent rotavirus gastroenteritis patients. However, the pathogenesis of rotavirus infection in immunocompromised transplant recipients remains unclear. Enzyme-linked immunosorbent assay was used to measure rotavirus antigen levels in serially collected serum samples obtained from 62 pediatric patients receiving allogeneic hematopoietic stem cell transplants (HSCT). Rotavirus antigen was detected in 43 (6.8%) of 633 serum samples (8 of 62 patients). The duration of rotavirus antigenemia ranged between 1 and 10 weeks, and diarrhea was concurrent with rotavirus antigenemia in Cases 3, 6, 7, and 8. The level of viral antigen in the transplant recipients (0.19 ± 0.20) was significantly lower than that observed in serum samples collected from immunocompetent patients on either day 1 (0.49 ± 0.18, P = 0.0011) or day 3 (0.63 ± 0.09, P = 0.0005). A patient who received a graft from a human leukocyte antigen (HLA)-mismatched donor was at significant risk for rotavirus antigenemia (P = 0.024; odds ratio = 9.44) in comparison to patients who received grafts from HLA-matched donors. Although the duration of antigenemia was clearly longer in HSCT patients than in immunocompetent rotavirus gastroenteritis patients, the levels of viral antigen were not as high. Therefore, mismatched HLA may be a risk factor for rotavirus antigenemia after HSCT.
Assuntos
Antígenos Virais/sangue , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Infecções por Rotavirus/virologia , Rotavirus/imunologia , Viremia/imunologia , Adolescente , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Ensaio de Imunoadsorção Enzimática , Feminino , Antígenos HLA/imunologia , Humanos , Lactente , Masculino , Fatores de Risco , Rotavirus/isolamento & purificação , Infecções por Rotavirus/sangue , Infecções por Rotavirus/fisiopatologia , Transplante Homólogo/efeitos adversos , Viremia/virologiaRESUMO
From January 1991 to March 2007, 61 children and adolescent with acquired severe aplastic anemia received BMT in our institutions. We retrospectively compared the outcome of 30 cases of matched-sibling donor BMT (MSD-BMT) and 31 cases of unrelated donor BMT (URD-BMT). We observed one graft failure among MSD-BMT recipients and three graft failures among URD-BMT recipients, respectively. No patients in the MSD-BMT group developed grades II-IV acute GVHD compared with 11 of 30 patients (37%) in the URD-BMT group (P<0.001). One of 30 MSD-BMT recipients (3%) developed chronic GVHD compared with 8 of 30 URD-BMT recipients (27%) (P=0.013). The incidence of EBV and CMV reactivation was 11 of 20 URD-BMT recipients and 23 of 30, respectively. One patient in the URD-BMT group died of a motor accident 5.5 years after BMT. Ten-year OS was 100% in MSD-BMT recipients and 93.8% (95% CI, 81.9-100%) in URD-BMT recipients, respectively (P=0.252). Ten-year failure-free survival was 96.7% (95% CI, 90.2-100%) in the MSD-BMT group and 84.7% (95% CI, 70.2-99.2%) in the URD-BMT group, respectively (P=0.161).
Assuntos
Anemia Aplástica/terapia , Transplante de Medula Óssea , Doadores de Tecidos , Adolescente , Anemia Aplástica/complicações , Transplante de Medula Óssea/efeitos adversos , Criança , Pré-Escolar , Citomegalovirus/fisiologia , Infecções por Citomegalovirus/complicações , Infecções por Vírus Epstein-Barr/complicações , Feminino , Rejeição de Enxerto/epidemiologia , Doença Enxerto-Hospedeiro/epidemiologia , Herpesvirus Humano 4/fisiologia , Histocompatibilidade , Humanos , Lactente , Masculino , Estudos Retrospectivos , Índice de Gravidade de Doença , Irmãos , Análise de Sobrevida , Condicionamento Pré-Transplante/métodos , Resultado do Tratamento , Ativação ViralRESUMO
OBJECTIVE: Insulin-like growth factor binding protein-1 (IGFBP-1) is known to regulate the bioavailability of insulin-like growth factor (IGF) and the levels of IGFBP-1 are increased in the morning in patients with type 1 diabetes mellitus. We investigated the nocturnal fluctuations of glucose, IGFBP-1, and free IGF-1 levels with three insulin regimens. RESEARCH DESIGN AND METHODS: Forty-eight type 1 diabetes patients were divided into three groups according to their basal insulin therapy (continuous subcutaneous insulin infusion [CSII], insulin glargine, NPH insulin). Blood samples were obtained every 2 h between 2 300 h and 0700 h to measure plasma glucose, IGFBP-1 and free IGF-1 levels. RESULTS: The dawn phenomenon was more frequent with NPH (62.1%) than with glargine (16.6%, p<0.05) and CSII (14.3%, p<0.05). In the NPH group, the serum IGFBP-1 levels were markedly increased from 21.0+/-3.6 ng/ml at 2 300 h to 200.3+/-21.8 ng/ml at 0700 h and free IGF-1 levels were inversely decreased; these changes were partially suppressed in the CSII and glargine groups. CONCLUSIONS: The use of insulin regimens that provide sufficient insulin levels in the early morning can suppress the dawn phenomenon, leading to improved glycemic control. The increase in circulating IGFBP-1 in the morning, as a result of waning of insulin action, lowers free IGF-1 levels and may cause insulin resistance.
Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 1/tratamento farmacológico , Insulina Isófana/administração & dosagem , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Insulina/análogos & derivados , Insulina/administração & dosagem , Adolescente , Glicemia/análise , Ritmo Circadiano/fisiologia , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/metabolismo , Feminino , Humanos , Insulina/uso terapêutico , Insulina Glargina , Sistemas de Infusão de Insulina , Insulina Isófana/uso terapêutico , Insulina de Ação Prolongada , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , MasculinoRESUMO
Late-onset non-infectious pulmonary complications (LONIPCs) that arise beyond 3 months after allogeneic hematopoietic SCT include bronchiolitis obliterans (BO), bronchiolitis obliterans with organizing pneumonia (BOOP) and idiopathic pneumonia syndrome (IPS). We retrospectively analyzed the incidence and outcome of LONIPCs among pediatric hematopoietic SCT recipients. We included 97 patients who survived for more than 3 months among the 114 who underwent allogeneic hematopoietic SCT between April 1997 and May 2007. Of the 97 enrolled patients, 10 (10.3%) developed LONIPCs at a median of 187 days after hematopoietic SCT (range, 123-826 days). Of the 10 patients with LONIPCs, eight had BO and two had IPS. Multivariate analysis showed that the onset of LONIPCs was associated with high-risk underlying disease and extensive chronic GVHD (hazard ratio, 5.42 (95% confidence interval, 1.36-21.7) and hazard ratio, 11.7 (95% confidence interval, 2.40-57.1), respectively). Only two patients responded to therapy with steroids and six of the 10 patients died. The 5-year OS rate was significantly lower among patients with, than without LONIPCs (28.0 vs 87.2%, P=0.000). Considering that we are lacking optimal therapies for LONIPCs, strategies aimed at the prevention of LONIPCs should be attempted.
Assuntos
Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Pneumopatias/etiologia , Adolescente , Bronquiolite Obliterante/etiologia , Criança , Pré-Escolar , Feminino , Doença Enxerto-Hospedeiro/etiologia , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Análise Multivariada , Estudos Retrospectivos , Fatores de Risco , Transplante Homólogo , Resultado do TratamentoRESUMO
AIMS: To determine the expression of Mcl-1 in testicular germ cell tumours in order to clarify the role of this anti-apoptotic factor in these tumours. Various members of the Bcl-2 family have been implicated in the apoptotic mechanisms regulating germ cell apoptosis. Mcl-1 is an anti-apoptotic Bcl-2 family member and has recently been reported to be related to the progression of malignancy; however, the involvement of Mcl-1 in the development of germ cell tumours is still unknown. METHODS AND RESULTS: Mcl-1 expression in testicular germ cell tumours was investigated by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). By immunohistochemistry, overexpression of Mcl-1 was present in all germ cell tumours that were studied, including embryonal carcinoma and yolk sac tumour, as well as choriocarcinoma and teratoma. In teratomas, Mcl-1 was widely distributed in the epithelial, myogenic, neural and mesenchymal components. RT-PCR analysis after microdissection revealed high levels of Mcl-1 mRNA in all tumour variants compared with non-neoplastic germ cells. CONCLUSION: Overexpression of anti-apoptotic Mcl-1 may function to enhance the viability of testicular germ cells, thereby leading to tumorigenesis.
Assuntos
Germinoma/patologia , Proteínas de Neoplasias/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Neoplasias Testiculares/patologia , Adolescente , Adulto , Regulação Neoplásica da Expressão Gênica , Germinoma/genética , Germinoma/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Proteína de Sequência 1 de Leucemia de Células Mieloides , Proteínas de Neoplasias/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias Testiculares/genética , Neoplasias Testiculares/metabolismoRESUMO
Fanconi anemia (FA) is an autosomal recessive disease with congenital anomalies, bone marrow failure, and susceptibility to leukemia. Patient cells show chromosome instability and hypersensitivity to DNA cross-linking agents. At least 8 complementation groups (A-G) have been identified and 6 FA genes (for subtypes A, C, D2, E, F, and G) have been cloned. Increasing evidence indicates that a protein complex assembly of multiple FA proteins, including FANCA and FANCG, plays a crucial role in the FA pathway. Previously, it was reported that FANCA was phosphorylated in lymphoblasts from normal controls, whereas the phosphorylation was defective in those derived from patients with FA of multiple complementation groups. The present study examined phosphorylation of FANCA ectopically expressed in FANCA(-) cells. Several patient-derived mutations abrogated in vivo phosphorylation of FANCA in this system, suggesting that FANCA phosphorylation is associated with its function. In vitro phosphorylation studies indicated that a physiologic protein kinase for FANCA (FANCA-PK) forms a complex with the substrate. Furthermore, at least a part of FANCA-PK as well as phosphorylated FANCA were included in the FANCA/FANCG complex. Thus, FANCA-PK appears to be another component of the FA protein complex and may regulate function of FANCA. FANCA-PK was characterized as a cytoplasmic serine kinase sensitive to wortmannin. Identification of the protein kinase is expected to elucidate regulatory mechanisms that control the FA pathway.
Assuntos
Citoplasma/enzimologia , Proteínas de Ligação a DNA , Anemia de Fanconi/enzimologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas/metabolismo , Androstadienos/farmacologia , Western Blotting , Linhagem Celular Transformada , Inibidores Enzimáticos/farmacologia , Proteína do Grupo de Complementação A da Anemia de Fanconi , Fibroblastos/metabolismo , Granulócitos/metabolismo , Células HeLa/metabolismo , Humanos , Técnicas de Imunoadsorção , Células Jurkat/metabolismo , Linfócitos/metabolismo , Fosforilação , Transfecção , WortmaninaRESUMO
BACKGROUND: This study was conducted in order to clarify whether histopathologic analysis of factor thymidine phosphorylase (TP) and Factor VIII could be a useful predictor of postoperative recurrence in localized renal cell carcinoma. Therefore, the relationship between tumor infiltrated lymphocytes (TIL) and both TP and Factor VIII was studied. METHOD: Of the 71 patients who underwent surgery, 54 patients had no neoadjuvant therapy (group 1), 10 patients were preoperatively administered IFN-gamma (group 2), and the remaining seven patients preoperatively received IFN-gamma and transarterial embolization (group 3). Both TP and Factor VIII immunostaining were performed on formalin-fixed, paraffin-embedded archival tissue from 71 renal cell carcinoma specimens, while TIL immunostaining was performed on frozen sections. Positive immunostaining was quantitatively scored by a computer-assisted digital image analysis. For TIL, positive results were semiquantitatively scored. RESULTS: A significant difference in the recurrence-free rate was recognized for Groups 1, 2 and 3 (P < 0.05). Therefore, the median TP-positive rate (PR), VIII-PR, number of microvessels and positive mean vascular area levels were investigated, between the recurrence cases (n = 6) and the recurrence-free cases (n = 11). Only the TP-PR levels showed a significant difference among them (P = 0.044). In regards to the neoadjuvant cases, a significant correlation was observed between both VIII-PR and CD4 (r = 0.815) as well as between VIII-PR and CD11b (r = 0.756). CONCLUSION: There was no clear evidence that the neoadjuvant treatment would increase the recurrence-free survival in patients with localized renal cell carcinoma. TP-PR might be a predictor of postoperative recurrence in patients with localized renal cell carcinoma.
Assuntos
Antineoplásicos/administração & dosagem , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/patologia , Interferon gama/administração & dosagem , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Renais/mortalidade , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Neoplasias Renais/mortalidade , Linfócitos/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Neovascularização Patológica/patologia , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores de Risco , Timidina Fosforilase/análise , Fator de von Willebrand/análiseRESUMO
We describe here the case of an 8-year-old girl with Fanconi anemia (FA) whose hematopoiesis was successfully restored by unrelated umbilical cord blood (UCB) transplantation. The patient became resistant to androgen therapy, and developed intracranial hemorrhage and dyserythropoiesis. Her hematopoietic recovery after the transplantation was excellent and a complete chimerism has been durably maintained. UCB should be considered as a stem cell source for transplantation when a patient with FA does not have an HLA-identical unaffected sibling donor.
Assuntos
Anemia de Fanconi/terapia , Hematopoese , Transplante de Células-Tronco Hematopoéticas , Pré-Escolar , Intervalo Livre de Doença , Anemia de Fanconi/complicações , Feminino , Sangue Fetal , Sobrevivência de Enxerto , Histocompatibilidade , Humanos , Hemorragias Intracranianas/etiologia , Quimeras de TransplanteRESUMO
We report a 13-year-old boy who developed dyspnea at rest 1 year after the occurrence of cGVHD following an allogeneic bone marrow transplant (BMT). Pulmonary function data, imaging studies, lung biopsy, and bronchoalveolar lavage were consistent with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). Although reports suggest that oral methylprednisolone or methylprednisolone pulse therapies improve BOOP after BMT, we treated our patient with a combination of oral prednisolone (1 mg/kg) and low dose erythromycin (10 mg/kg) to avoid the side-effects of high-dose steroids. With this therapy, our patient showed clinical and radiological improvements within 1 week. The steroids were tapered off 12 months later and erythromycin was given for 14 months. We conclude that therapy consisting of a combination of oral prednisolone and low-dose erythromycin for BOOP after BMT may minimize the dose and duration of steroid use.
Assuntos
Transplante de Medula Óssea/efeitos adversos , Pneumonia em Organização Criptogênica/tratamento farmacológico , Eritromicina/administração & dosagem , Prednisolona/administração & dosagem , Administração Oral , Adolescente , Pneumonia em Organização Criptogênica/etiologia , Quimioterapia Combinada , Doença Enxerto-Hospedeiro/etiologia , Humanos , Masculino , Transplante HomólogoRESUMO
A 10-year-old girl presented with massive pericardial/pleural effusion with anasarca 216 days after an allogeneic bone marrow transplantation from her HLA-matched sibling for relapsed acute lymphoblastic leukemia. She did not show any other symptoms of chronic graft-versus-host disease (GVHD). The antinucleolar antibody was elevated in the blood and the pleural fluid. The lymphocytes in the fluid were mostly CD8+/HLA-DR+, and a majority of CD8+ cells in the blood expressed CD57. These data suggested that she had chronic GVHD. Immunosuppressive therapy including prednisolone, cyclosporin A, high-dose methylprednisolone, tacrolimus (FK506), and methotrexate had no effect, and the patient died of Aspergillus pneumonia 183 days after the presentation of the disease. Although it has not been described before, isolated serositis with edema should be recognized as a clinical feature of chronic GVHD.
Assuntos
Transplante de Medula Óssea/efeitos adversos , Edema/etiologia , Derrame Pericárdico/etiologia , Derrame Pleural/etiologia , Antígenos CD/sangue , Aspergilose/etiologia , Criança , Evolução Fatal , Feminino , Doença Enxerto-Hospedeiro/etiologia , Humanos , Núcleo Familiar , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Transplante Homólogo/efeitos adversosRESUMO
Here, we demonstrate a significant ex vivo expansion of human hematopoietic stem cells capable of repopulating in NOD/SCID mice. Using a combination of stem cell factor (SCF), Flk2/Flt3 ligand (FL), thrombopoietin (TPO), and a complex of IL-6 and soluble IL-6 receptor (IL-6/sIL-6R), we cultured cord blood CD34(+) cells for 7 days and transplanted these cells into NOD/SCID mice. Bone marrow engraftment was judged successful when recipient animals contained measurable numbers of human CD45(+) cells 10-12 weeks after transplantation. When cells were cultured with SCF+FL+TPO+IL-6/sIL-6R, 13 of 16 recipients were successfully engrafted, and CD45(+) cells represented 11.5% of bone marrow cells in engrafted recipients. Cells cultured with a subset of these factors were less efficiently engrafted, both as measured by frequency of successful transplantations and prevalence of CD45(+) cells. In animals receiving cells cultured with all 4 factors, human CD45(+) cells represented various lineages, including a large number of CD34(+) cells. The proportion of CD45(+) cells in recipient marrow was 10 times higher in animals receiving these cultured cells than in those receiving comparable numbers of fresh CD34(+) cells, and the expansion rate was estimated at 4.2-fold by a limiting dilution method. Addition of IL-3 to the cytokine combination abrogated the repopulating ability of the expanded cells. The present study may provide a novel culture method for the expansion of human transplantable hematopoietic stem cells suitable for clinical applications.
Assuntos
Hematopoese/efeitos dos fármacos , Células-Tronco Hematopoéticas/citologia , Interleucina-6/metabolismo , Proteínas de Membrana/metabolismo , Receptores de Interleucina-6/metabolismo , Fator de Células-Tronco/metabolismo , Trombopoetina/metabolismo , Animais , Antígenos CD34 , Transplante de Medula Óssea , Meios de Cultura Livres de Soro , Humanos , Interleucina-3/farmacologia , Interleucina-6/farmacologia , Proteínas de Membrana/farmacologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Solubilidade , Fator de Células-Tronco/farmacologia , Trombopoetina/farmacologia , Transplante HeterólogoRESUMO
Fanconi anemia (FA) is an autosomal recessive disease characterized by congenital anomalies, aplastic anemia, and a susceptibility to leukemia. There are at least 8 complementation groups (A through H). Extensive analyses of the FA group C gene FANCC in Western countries revealed that 10% to 15% of FA patients have mutations of this gene. The most common mutation is IVS4 + 4 A to T (IVS4), a splice mutation in intron 4, which has been found only in patients of Ashkenazi Jewish ancestry. When we screened 29 Japanese patients (20 unrelated patients and 4 families) using polymerase chain reaction-single strand conformation polymorphism, we found 8 unrelated patients homozygous for IVS4. This is apparently the first non-Ashkenazi-Jewish population for whom this mutation has been detected. The Ashkenazi Jewish patients homozygous for IVS4 have a severe phenotype, in comparison with other FA patients. Our analyses of Japanese patients indicate no significant difference between IVS4 homozygotes and other patients with regard to severity of a clinical phenotype. Thus, ethnic background may have a significant effect on a clinical phenotype in FA patients carrying the same mutation. (Blood. 2000;95:1493-1498)
Assuntos
Proteínas de Ciclo Celular , Anormalidades Congênitas/genética , Proteínas de Ligação a DNA , Anemia de Fanconi/genética , Proteínas Nucleares , Polimorfismo Conformacional de Fita Simples , Proteínas/genética , Deleção de Sequência , Adolescente , Adulto , Idade de Início , Processamento Alternativo , Povo Asiático/genética , Sequência de Bases , Criança , Europa (Continente)/etnologia , Éxons , Família , Proteína do Grupo de Complementação C da Anemia de Fanconi , Proteínas de Grupos de Complementação da Anemia de Fanconi , Feminino , Homozigoto , Humanos , Íntrons , Japão , Judeus/genética , Masculino , Reação em Cadeia da PolimeraseRESUMO
The purpose of this study was to demonstrate the benefits of cytoreductive surgery for renal cell carcinomas that also involve the liver. Between 1994 and 1997, four patients with renal cell carcinoma with liver involvement were surgically treated with nephrectomy and hepatectomy. Two of them underwent a simultaneous hepatectomy and nephrectomy (group 1), and the remaining two patients underwent a hepatectomy after a nephrectomy and had a diagnosis of postoperative recurrence (group 2). Two patients, one from each group, died of multiple bone metastasis and lung metastasis 30 months and 12 months after the hepatectomy; the second patient from group 1 died 40 months after the first operation due to gastrointestinal hemorrhaging. The second patient from group 2 displayed no evidence of recurrence 18 months after the second surgical procedure. The survival rates for these patients were 66% and 33% at 1 and 3 years, respectively. Autopsy studies revealed that one patient from group 2 had a local recurrence in the liver while the other two patients from group 1 did not. Our results suggested that a progressive approach may therefore be useful for patients demonstrating renal cell carcinoma where there is liver involvement.
Assuntos
Carcinoma de Células Renais/cirurgia , Hepatectomia , Neoplasias Renais/cirurgia , Neoplasias Hepáticas/cirurgia , Nefrectomia , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/secundário , Humanos , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Taxa de SobrevidaRESUMO
The present study investigated the effect on certain physical properties of adding various amounts of hydroxyapatite (HAP) to chitosan sol. Also investigated were connective tissue reactions to a composite membrane that is being developed for possible use in guided tissue regeneration and for the limitation of HA particle migration at sites of implantation. The physical properties evaluated were shrinkage, tensile strength, hardness, calcium ion release, and morphology. Assessment of physical properties indicated that a ratio of HA to chitosan sol of 4/11 by weight is optimal in the preparation of the composite membrane. Subperiosteal implantation of the membranes over rat calvaria revealed that the membranes were well tolerated, with fibrous encapsulation and occasional areas of osteogenesis. Increasing the hydroxyapatite content seems to enhance membrane degradation.
Assuntos
Materiais Biocompatíveis/química , Biopolímeros/química , Quitina/análogos & derivados , Tecido Conjuntivo/efeitos dos fármacos , Durapatita/química , Animais , Materiais Biocompatíveis/toxicidade , Biopolímeros/toxicidade , Cálcio/química , Quitina/química , Quitina/toxicidade , Quitosana , Durapatita/toxicidade , Microanálise por Sonda Eletrônica , Testes de Dureza , Masculino , Teste de Materiais , Microscopia Eletrônica de Varredura , Ratos , Ratos Sprague-Dawley , Solubilidade , Propriedades de Superfície , Resistência à TraçãoRESUMO
Membranes made of 65, 70, 80, 94, and 100% deacetylated chitin (chitosan) were implanted subperiosteally over the calvaria of 100 rats. Reactions were studied at 1, 2, 4, and 8 weeks after implantation. Membranes prepared with 65, 70, and 80% deacetylated chitin initially elicited marked inflammatory reactions that subsided in time with granulation tissue formation and osteogenesis. Osteocalcin-positive cells were detected immunohistochemically in the granulation tissue. On the other hand, membranes made of 94% deacetylated chitin and chitosan showed mild inflammation and minimal osteogenesis. The results indicate that membranes made of 65, 70, and 80% deacetylated chitin enhance osteogenesis at the site of their implantation. However, the initially severe inflammatory reaction associated with these materials needs to be controlled before the materials would be suitable for clinical application.
Assuntos
Quitina/análogos & derivados , Membranas Artificiais , Próteses e Implantes , Crânio/patologia , Acetilação , Animais , Quitosana , Imuno-Histoquímica , Masculino , Ratos , Ratos Sprague-Dawley , Crânio/metabolismoRESUMO
We studied the effectiveness of antithymocyte globulin (ATG) in preventing acute graft-versus-host disease (a-GVHD) in children who received bone marrow transplants from unrelated HLA-matched donors at one institution. Of 39 patients who received transplants between 1993 and 1997, 23 were given ATG on the basis of informed consent. Either Thymoglobulin (Pasteur Merieux, 2.5 mg/kg/day) or Lymphoglobulin (15 mg/kg/day) was administered for 4 days. a-GVHD (> or = grade II) developed in 33% of the ATG group (n = 21) and in 44% of the non-ATG group (n = 16). Although a-GVHD (> or = grade II) appeared less frequent in the ATG group, the difference was not statistically significant. Among the subjects with hematological malignancies, no significant difference was observed in frequency of a-GVHD (> or = grade II) or 3-year survival rate for the ATG group (n = 10) and non-ATG group (n = 16). However, the incidence of cytomegalovirus infection was much higher (p < 0.01) in the ATG group (70%) than in the non-ATG group (19%). From this study, we were not able to confirm the benefits of ATG as described by other investigators.
Assuntos
Soro Antilinfocitário/uso terapêutico , Transplante de Medula Óssea , Doença Enxerto-Hospedeiro/prevenção & controle , Imunossupressores/uso terapêutico , Linfócitos T/imunologia , Doença Aguda , Adolescente , Adulto , Criança , Pré-Escolar , Infecções por Citomegalovirus/etiologia , Feminino , Humanos , Lactente , Masculino , Complicações Pós-Operatórias , Resultado do TratamentoRESUMO
The present study investigated properties of various mixtures of organic acids (malic and malonic) and calcium phosphate compounds (beta-tricalcium phosphate, ashed bovine bone, and synthetic hydroxyapatite) with the objective of determining the optimum combination of organic acid and calcium phosphate compound for components of a chitosan-bonded bone-filling paste. beta-tricalcium phosphate was decomposed by malic acid and malonic acid, but these two acids did not decompose synthetic hydroxyapatite and ashed bovine bone. Assessment of ion release from a set paste containing either synthetic hydroxyapatite or ashed bovine bone indicated that only calcium ions were appreciably released after storing and stirring the set paste in physiologic saline for 7 days.
Assuntos
Materiais Biocompatíveis , Cimentos Ósseos , Fosfatos de Cálcio , Quitina/análogos & derivados , Animais , Bovinos , QuitosanaRESUMO
Bone filling substances are needed to meet several requirements including nontoxicity, setting time, changes in pH values, and amount of dissolved elements as well as mechanical properties. In this study, the bone-generating composites were prepared by employing the in vivo absorbable beta-tricalcium phosphate as a parent matrix kneaded with CaO, MgO, and ZnO as bone mineral additives with different compositions. The setting time, pH values, compressive strength were investigated as a function of the amount of these bone mineral additives. It was found that the setting time was shortened by increasing CaO, MgO, and ZnO contents. Increasing ZnO contents resulted in the pH value lower, while the pH values increased by increasing CaO and MgO contents. Increasing ZnO contents caused the compressive strength stronger, on the other hand, the compressive strength was weakened by increasing MgO contents. Furthermore, calcium appears to be selectively released from the hardened composite sample.
Assuntos
Materiais Biocompatíveis , Osso e Ossos/cirurgia , Fosfatos de Cálcio/química , Resinas Compostas/química , Análise de Variância , Compostos de Cálcio/química , Quelantes , Quitina/análogos & derivados , Quitosana , Microanálise por Sonda Eletrônica , Humanos , Concentração de Íons de Hidrogênio , Óxido de Magnésio/química , Modelos Biológicos , Óxidos/química , Propriedades de Superfície , Resistência à Tração , Óxido de Zinco/químicaRESUMO
For clarification of the histological details of the shedding of human deciduous teeth, exfoliated and extracted deciduous teeth were examined by light and electron microscopy. After the roots were completely resorbed, the dentogingival junction migrated along the inner resorbing surface and finally reached the pulpal surface of the crown. At the same time, the gingival epithelium also proliferated and migrated under the crown of the deciduous tooth in such a way that part of it lined the residue of the pulp and another part lined the surface overlying the erupting successional tooth. This phenomenon took place from various sides of the tooth surface. Therefore, just before exfoliation, the migrated gingival epithelium formed narrow necks of tissue, and the crown was only superficially attached to the gingiva by them. The final shedding of the tooth appeared to occur by a tearing of these narrow tissue regions. The results of the present study suggest that the dento-gingival junction as well as gingival epithelium play important roles in the process of exfoliation of human deciduous teeth.