RESUMEN
O envelhecimento é um processo fisiológico que traz consigo uma série de alterações no organismo que se estendem até o nível molecular. Diante disto, este é um processo complexo que afeta diversos tecidos, sendo um deles o hematopoético, local onde, através de interações da Célula Tronco Hematopoética (CTH) com o ambiente ao seu redor, incluindo a Célula Tronco Mesenquimal (CTM), ocorre a hematopoese. Embora já sejam descritas na literatura algumas alterações na medula óssea consequentes do envelhecimento, os mecanismos por trás de tais mudanças permanecem elusivas, principalmente no âmbito das interações celulares ocorrentes na medula óssea. Portanto, este trabalho buscou investigar como o envelhecimento afeta a regulação hematopoética no contexto de sua relação com as CTM medulares. Para esta pesquisa, foram utilizados camundongos machos isogênicos da linhagem C57BL/6, dividindoos em grupos conforme sua idade: jovens (3 5 meses) e idosos (18 19 meses). Foi realizada a caracterização do modelo através de aspectos físicos como consumo proteico, variação de peso, entre outros, seguido de avaliação bioquímica e hematológica. Adicionalmente, foram coletadas células medulares e, posteriormente, realizado o isolamento das CTMs. Para estudar a relação destas células com a hematopoese, foram realizados ensaios in vitro utilizando a linhagem celular leucêmica C1498 (TIB-49™, ATCC®) mantidas em contato com o sobrenadante das CTMs isoladas. Quanto aos parâmetros bioquímicos, os animais idosos apresentaram menores níveis de albumina, aspartato alanina transferase (ALT) e de triglicerídeos quando comparados aos animais jovens. Contrariamente, os animais idosos apresentaram um maior nível de colesterol. Na avaliação hematológica, foi constatado pelo hemograma que os animais idosos apresentaram valores comparáveis aos animais jovens, todavia, o mielograma mostrou menor celularidade geral, seguido de menor número de células da linhagem eritroide e maior número de precursores granulocíticos. Através da imunofenotipagem, foi revelado um maior número de CTHs e de precursores grânulosmonocíticos na medula de animais idosos quando comparado aos jovens, e uma menor frequência de progenitores linfoides. Na imunofenotipagem de sangue periférico de animais idosos houve uma redução no número de linfócitos B e de eritrócitos, e aumento na população de células natural killers. Na imunofenotipagem de CTMs, o marcador CD73 apresentou menor expressão nos animais idosos. Avaliando o secretoma destas células estromais, foram encontrados no sobrenadante de CTMs de animais idosos aumentos significativos nas concentrações de CXCL12 e SCF e redução de IL-11. No âmbito molecular, as CTMs de animais idosos apresentaram aumento na expressão de Akt1, Nos e Ppar-γ, e redução na expressão de Csf3 e Cdh2. Adicionalmente, quando comparado a ação das CTMs de animais idosos em relação as CTMs de animais jovens, observou-se que CTMs de animais idosos foram capazes de aumentar a expressão de Sox2, Pou5f1 e Nanog e diminuir a expressão de Cdkn1a de células da linhagem C1498. O sobrenadante de CTMs de animais idosos também resultou na maior proliferação e migração de células da linhagem C1498. Portanto, levando em consideração a importância das CTMs sobre a regulação do sistema hematopoético, pode-se concluir que, no envelhecimento, as CTMs criam um ambiente propício para a proliferação celular no qual a manutenção da pluripotência é estimulada, o que pode acarretar em uma desregulação do sítio hematopoético quando habitado por células malignas
Aging is a physiological process in which occurs a series of alterations in an organism that extend to a molecular level. It is a complex process that affects various tissues, one of them being the bone marrow, wherethrough the interactions of the hematopoietic stem cell (CTH) with its surrounding environment, including with the mesenchymal stem cell (CTM), hematopoiesis takes place. Although some aging-associated alterations in the bone marrow can be found described in the literature, the mechanisms behind said changes remain elusive, especially when regarding the cellular interactions present inside the bone marrow. Therefore, this research aimed to investigate how aging affects the regulation of hematopoiesis in the context of its interactions with bone marrow-derived CTMs. For this investigation, male isogenic C57BL/6 mice were used as animal models. These were separated in two groups according to their age: young (3 5 months) and aged (18 19 months). The animal models were characterized by their physical properties such as protein intake and weight variation, followed by biochemical and hematological evaluation. Bone marrow cells were obtained and identified through immunophenotyping, thus isolating different cell populations, including the CTMs. To study the relationship between these cells and hematopoiesis, in vitro assays were conducted utilizing the leukemic cell lineage C1498 (TIB-49™, ATCC®) maintained in contact with the supernatant of isolated CTMs. By their biochemical profile, aged mice showed lower levels of albumin, alanine-aspartate transferase (ALT) and triglycerides compared to the young group. In contrast, aged mice had a higher cholesterol level. Hematological evaluation by total blood count showed similar results between the two groups, however, the myelogram revealed that the aged animals had lower cellularity, with less frequent cells from the erythroid lineage, with an increase in granulocytic precursors. Through immunophenotyping, it was also revealed that aged mice have higher numbers of hematopoietic stem cells, while also being noted a reduced population of lymphoid progenitors. An increase in the granulomonocytic progenitors was also found. Immunophenotyping peripheral blood cells of aged mice revealed reduced numbers of B lymphocytes and erythrocytes, and an increased natural killer cell population. Additionally, the cell surface marker CD73 was found to be less expressed in aged mice CTMs. The secretome of these stromal cells obtained from aged mice showed higher levels of CXCL12 and SCF, and lower levels of IL-11when compared to the young counterparts. At a molecular level, CTMs obtained from aged mice expressed more Akt1, Nos and Ppar-γ, while the expression of Csf3 and Cdh2 was reduced. Additionally, when comparing the effects of aged mice CTMs with young mice CTMs, it was observed that the first expressed were capable of increasing the expression of Sox2, Pou5f1 and Nanog, while decreasing Cdkn1a expression in the C1498 cell lineage. The supernatant obtained from aged mice also favored the proliferation and cell migration of the C1498 cell line. Thus, considering the importance that CTMs have over the hematopoietic system, we can conclude that, in aging, CTMs create a special environment which favors cell proliferation and maintenance of pluripotency, which can result in a dysregulation of the hematopoietic tissue when malignant cells are present
Asunto(s)
Animales , Masculino , Ratones , Envejecimiento/metabolismo , Células Madre Mesenquimatosas/clasificación , Hematopoyesis/genética , Células Madre Hematopoyéticas/clasificación , Sistema Hematopoyético/anomalíasRESUMEN
The characterization of hematopoietic stem cells (HSC) from the canine yolk sac (cYS) can contribute to future gene therapies because it is possible to obtain information about the beginning of the development of the circulatory system through the characterization. The cYS is a likely source of HSC, which is a source of blood cell development in mammals. Studies in this field have been conducted for decades; however, interest in cellular therapy is currently at its peak with greater visibility, and these cells are a promising therapeutic tool for the treatment of diseases related to animals and humans. The aim of this study was to isolate and characterize HSC from the cYS embryos at 30 to 45 days of gestational age. Our results showed that the cYS was macroscopically located in the ventral region with a central portion and extremities. The cells in culture presented a circular morphology and cell clusters. The average cell viability was 22.55% dead cells out of 6.5 × 104 total cells. The cells were also able to form colonies on methylcellulose. Flow cytometry analysis revealed the expression of CD34, CD117, and CD45. Our results suggest that the cYS can be used as a source of hematopoietic cells, and this study is very important to understand the mechanism and development of the hematopoietic system in dogs.(AU)
Asunto(s)
Animales , Perros , Perros , Células Madre Hematopoyéticas/clasificación , Saco Vitelino , Sistema HematopoyéticoRESUMEN
O nicho endosteal da medula óssea abriga as células-tronco hemopoéticas (CTH) em quiescência/autorrenovação. As CTH podem ser classificadas em dois grupos: células que reconstituem a hemopoese em longo prazo (LT-CTH) e curto prazo (CT-CTH). Investigamos, neste trabalho, os efeitos da desnutrição proteica (DP) no tecido ósseo e a participação do nicho endosteal na sinalização osteoblasto-CTH. Para tanto, utilizamos camundongos submetidos à DP induzida pelo consumo de ração hipoproteica. Os animais desnutridos apresentaram pancitopenia e diminuição nas concentrações de proteínas séricas e albumina. Quantificamos as CTH por citometria de fluxo e verificamos que os desnutridos apresentaram menor porcentagem de LT-CTH, CT-CTH e de progenitores multipotentes (PMP). Avaliamos a expressão das proteínas CD44, CXCR4, Tie-2 e Notch-1 nas LT-CTH. Observamos diminuição da expressão da proteína CD44 nos desnutridos. Isolamos as células LT-CTH por cell sorting e avaliamos a expressão gênica de CD44, CXCR4 e NOTCH-1. Verificamos que os desnutridos apresentaram menor expressão de CD44. Em relação ao ciclo celular, verificamos maior quantidade de LT-CTH nas fases G0/G1. Caracterizamos as alterações do tecido ósseo femoral, in vivo. Observamos diminuição da densidade mineral óssea e da densidade medular nos desnutridos. A desnutrição acarretou diminuição da área média das seções transversais, do perímetro do periósteo e do endósteo na cortical do fêmur dos animais. E na região trabecular, verificou-se diminuição da razão entre volume ósseo e volume da amostra e do número de trabéculas, aumento da distância entre as trabéculas e prevalência de trabéculas ósseas em formato cilíndrico. Avaliamos a expressão de colágeno, osteonectina (ON) e osteocalcina (OC) por imuno-histoquímica, e de osteopontina (OPN) por imunofluorescência no fêmur e verificamos diminuição da marcação para OPN, colágeno tipo I, OC e ON nos desnutridos. Evidenciamos, pela técnica do Picrosírius, desorganização na distribuição das fibras colágenas e presença de fibras tipo III nos fêmures dos desnutridos, além de maior número de osteoclastos evidenciados pela reação da fosfatase ácida tartarato resistente. Os osteoblastos da região femoral foram isolados por depleção imunomagnética, imunofenotipados por citometria de fluxo e cultivados em meio de indução osteogênica. Observamos menor positividade para fosfatase alcalina e vermelho de alizarina nas culturas dos osteoblastos dos desnutridos. Avaliamos, por Western Blotting, a expressão de colágeno tipo I, OPN, osterix, Runx2, RANKL e osteoprotegerina (OPG), e, por PCR em tempo real, a expressão de COL1A2, SP7, CXCL12, ANGPT1, SPP1, JAG2 e CDH2 nos osteoblastos isolados. Verificamos que a desnutrição acarretou diminuição da expressão proteica de osterix e OPG e menor expressão gênica de ANGPT1. Avaliamos a proliferação das células LSK (Lin-Sca1+c-Kit+) utilizando ensaio de CFSE (carboxifluoresceína succinimidil ester). Foi realizada cocultura de células LSK e osteoblastos (MC3T3-E1) na presença e ausência de anti-CD44. Após uma semana, verificamos menor proliferação das LSK dos desnutridos. O bloqueio de CD44 das LSK do grupo controle diminuiu a proliferação destas em três gerações. Entretanto, nos desnutridos, esse bloqueio não afetou a proliferação. Concluímos que a DP promoveu alterações no tecido ósseo e nas CTH. Entretanto, não podemos afirmar que as alterações observadas no sistema hemopoético foram decorrentes de alterações exclusivas do nicho endosteal
The bone marrow endosteal niche hosts hematopoietic stem cells (HSC) in quiescence/self-renewal. HSC can be classified into two groups: cells capable of renewing indefinitely (LT-HSC) or repopulating in the short term (ST-HSC). In this work, we investigated the effects of protein malnutrition (PM) on bone tissue and the involvement of the endosteal niche in osteoblast-CTH signaling. Therefore, we used mice subjected to PM induced by the consumption of hypoproteic feed. Malnourished animals presented pancytopenia and decreased concentration of serum protein and albumin. We quantified the HSC by flow cytometry and found that the malnourished ones had lower percentage of LT-HSC, ST-HSC and multipotent progenitors (MPP). We assessed the expression of the CD44, CXCR4, Tie-2 and Notch-1 proteins in LT-HSC. We observed decreased expression of CD44 protein with the malnourished ones. We isolated the LT-HSC cells by means of cell sorting and assessed the gene expression of CD44, CXCR4 and NOTCH-1. We found that malnutrition had lower expression of CD44. Regarding the cell cycle, we see greater amount of LT-HSC in the G0 and G1 phases. We characterized the changes of the femoral bone tissue in vivo. We observed a decrease in the bone mineral density and medullar density in malnourished animals. As for malnourished animals, the femoral cortical region showed a significant decrease in tissue area, periosteal and endosteal perimeter. The femoral trabecular region of malnourished animals showed decreased bone volume/tissue volume ratio, decreased trabecular number, increased trabecular separation and prevalence of rod-like trabeculae. We investigated the expression of collagen, osteonectin (ON) and osteocalcin (OC) by means of immunohistochemistry and the expression of osteopontin (OPN) by immunofluorescence and we found that malnourished animals showed decreased labeling for OPN, type I collagen, OC and ON in the cortical region of the femur. Picrosirius staining was used to analyze disorganization of collagen fibers and presence of type III fibers in the femurs of the malnourished. Cortical and trabecular regions of malnourished animals presented a higher number of osteoclasts as shown by tartrate-resistant acid phosphatase reaction. Moreover, osteoblasts were isolated from the femoral region by immunomagnetic depletion and immunophenotyped by flow cytometry and cultured in osteogenic induction medium. Results proved less positive for alkaline phosphatase and alizarin red in the cultures of osteoblasts of malnourished animals. We assessed, by means of Western blotting, type I collagen expression, OPN, osterix, Runx2, RANKL and osteoprotegerin (OPG) and, by real time PCR, the expression of COL1A2, SP7, CXCL12, ANGPT1, SPP1, JAG2 and CDH2 with the isolated osteoblasts. We found that malnutrition led to osterix and OPG decreased protein expression and lower ANGPT1 gene expression. We evaluated LSK cell (Lin-Sca1+c-Kit+) proliferation by CFSE (carboxyfluorescein succinimidyl ester). LSK cells and osteoblasts (MC3T3-E1) cocultures were performed in the presence and absence of anti-CD44. After a week, we found lower proliferation of LSK in the malnourished. The LSK CD44 blocking in the control group decreased the proliferation of these three generations. However, as for the malnourished, such blockage did not affect proliferation. We concluded that the PM has promoted changes in bone tissue and the CTH. However, we can't claim that the alterations observed in hematopoietic system were due to endosteal niche-only changes
Asunto(s)
Animales , Masculino , Ratones , Desnutrición , Osteocondrodisplasias , Western Blotting/métodos , Médula Ósea , Células Madre Hematopoyéticas/clasificación , /complicaciones , Investigación con Células MadreRESUMEN
BACKGROUND: Bone marrow (BM) blast count is an essential parameter for classification and prognosis of myelodysplastic syndromes (MDS). However, a high degree of cell atypias in bone marrow hemopoietic cells may be found in this group of clonal disorders, making it difficult to quantify precisely myeloblasts, and to distinguish them from promyelocytes and atypical immature myeloid precursors. Our aim was to investigate whether computerized image analysis of routine cytology would help to characterize these cells. METHODS: In May-Grünwald-Giemsa stained BM smears of 30 newly diagnosed MDS patients and 19 cases of normal BM, nuclei of blasts and promyelocytes were digitalized and interactively segmented. The morphological classification of the cells was done by consensus of two observers. Immature granulocytic precursors, which could not be clearly classified either as blasts or promyelocytes, were called "atypic myeloid precursors". Nuclear morphometry and texture features derived from the co-occurrence matrix and fractal dimension (FD) were calculated. RESULTS: In normal BM, when compared to myeloblasts, nuclei of promyelocytes showed significant increase in perimeter and local texture homogeneity and a decrease in form factor, chromatin gray levels, Haralick's entropy, inertia, energy, contrast, diagonal moment, cluster prominence, the fractal dimension according to Minkowski and its goodness-of-fit. Compared to normal myeloblast nuclei, the chromatin texture of MDS myeloblasts revealed higher local homogeneity and goodness-of-fit of the FD, but lower values of entropy, contrast, diagonal moment, and fractal dimension. The same differences were found between nuclei of normal promyelocytes and those of MDS. Nuclei of atypical myeloid precursors showed intermediate characteristics between those of blasts and promyelocytes according to the quantitative features (perimeter, form factor, gray level and its standard deviation), but were similar to promyelocytes according to the texture variables inertia, energy, contrast, diagonal moment, cluster prominence, and Minkowski's fractal dimension. CONCLUSION: BM atypical immature myeloid precursors are difficult to be correctly classified in routine cytology. Although their cytoplasm is more similar to that of myeloblasts, computerized texture analysis indicates a nuclear chromatin remodeling more close to the promyelocyte, thus indicating an asynchronous intermediate maturation stage between blast and promyelocyte.
Asunto(s)
Células Madre Hematopoyéticas/patología , Procesamiento de Imagen Asistido por Computador/métodos , Síndromes Mielodisplásicos/patología , Células Mieloides/patología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Células Madre Hematopoyéticas/clasificación , Humanos , Masculino , Persona de Mediana Edad , Células Mieloides/clasificación , Adulto JovenRESUMEN
La leucemia linfoblástica aguda (LLA) se caracteriza por la proliferación clonal y acumulación de células linfoides malignas en médula ósea y en sangre periférica. Identificar los aspectos clínico-hematológicos, evolución terapéutica y morbimortalidad en niños con LLA de novo tratados con el Protocolo Total XV modificado, en el Servicio de Hematología del Hospital Universitario de Caracas (HUC) entre 2003-2007. Estudio clínico-epidemiológico, descriptivo y retrospectivo mediante la revisión de historias clínicas de pacientes menores de18 años. Los síntomas clínicos al diagnóstico fueron hipertermia, astenia, cefalea, hiporexia, sangrado y dolor óseo; los signos: adenopatías, hepatoesplenomegalia y fiebre; mayor prevalencia en el género masculino: 64,7% y entre 1 a 10 años (67,7%). La mayoría presentó anemia, leucocitosis y trombocitopenia. La infiltración del SNC fue del 5,9%. Se obtuvo un 79,4% de remisión completa (RC)en la fase de inducción, la morbilidad principal fue por neutropenia febril y 8,7% de mortalidad. En la fase de consolidación, se mantuvo la tasa de RC (79,9%), la morbilidad fue por hepatotoxicidad y 6,8% de mortalidad. En la fase de mantenimiento, se mantuvo la tasa de RC 80% pero se presentó un 11,6% de recaídas, mayor morbilidad infecciosa y 19,2% de mortalidad. La sobrevida global (SG) y la sobrevida libre de enfermedad (SLE) con una mediana de seguimiento de 24 meses, fue: 57% y 18,8%, respectivamente. La estrategia para adaptar el Protocolo Total XV modificado en el Servicio de Hematología, no fue efectiva para mejorar la SG ni SLE al compararlo con la literatura internacional.
Acute lymphoblastic leukemia (ALL) is characterized by clonal proliferation and accumulation of malignant lymphoidcells in bone marrow and peripheral blood. To identify clinical and hematological aspects, therapeutic outcome and morbid mortality in children with de novo ALL treated with the modified Total Protocol XV, in the Department of Hematology, Hospital Universitario de Caracas (HUC) between 2003-2007. Clinical and epidemiological, descriptive, retrospective study by reviewing medical records of patients under 18 years. Clinical symptoms at diagnosis were hyperthermia, fatigue, headache, anorexia, bleeding and bone pain. Signs were lymphadenopathy, hepatosplenomegaly and fever, more prevalent in male 64.7% and in patients between 1 and 10 years (67.7 %). Mosthad anemia, leukocytosis and thrombocytopenia. CNS infiltration was present in 5.9%. We obtained a 79.4% complete remission (CR) in the induction phase, the major morbidity was febrile neutropenia and 8.7% mortality. In the consolidation phase, CR rate remained thesame (79.9%), morbidity was 6.8% for hepatotoxicity and mortality. In the maintenance phase, CR rate was 80% but there was an 11.6% relapse, and the infectious morbidity and mortality rate increased to 19.2%. Overall survival (OS) and disease-free survival (DFS) with a median follow-up of 24 months was 57% and 18.8% respectively. The strategy to adapt the Total Protocol XV modified in the Hematology Department was not effective in improving the OS and SLE when compared with international literature.
Asunto(s)
Humanos , Masculino , Femenino , Lactante , Preescolar , Niño , Adolescente , Células Madre Hematopoyéticas/clasificación , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Cuidado del Niño , Registros Médicos , Posología Homeopática/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/normasRESUMEN
Peripheral blood progenitor cell (PBPC) harvests mobilized by granulocyte colony-stimulating factor (G-CSF) contain more CD34+ cells and provide more rapid engraftment than do bone marrow (BM) harvests. However, some reports have suggested a higher risk of chronic graft-versus-host disease (GVHD), possibly because such PBPC harvests contain approximately 10 times more T lymphocytes than do BM harvests. Some groups are attempting to combine the faster engraftment of PBPCs with the lower incidence of GVHD observed after BM transplantation by using G-CSF-primed BM conventionally harvested from iliac crests for allogenic BM transplantation. We report the results of a pilot study of 38 allogeneic transplants using G-CSF-stimulated BM from related donors, with a focus on the harvest composition, engraftment, and incidence of acute and chronic GVHDs.
Asunto(s)
Trasplante de Médula Ósea/métodos , Supervivencia de Injerto , Enfermedad Injerto contra Huésped/inmunología , Factor Estimulante de Colonias de Granulocitos/farmacología , Neoplasias Hematológicas/terapia , Células Madre Hematopoyéticas/efectos de los fármacos , Subgrupos de Linfocitos T/efectos de los fármacos , Enfermedad Aguda , Adolescente , Adulto , Trasplante de Médula Ósea/mortalidad , Causas de Muerte , Niño , Preescolar , Enfermedad Crónica , Países en Desarrollo , Femenino , Neoplasias Hematológicas/mortalidad , Células Madre Hematopoyéticas/clasificación , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Subgrupos de Linfocitos T/clasificación , Trasplante Homólogo , Resultado del TratamientoRESUMEN
The presence of phenotypically immature lymphocytes in umbilical cord blood has been a controversial topic. Moreover, their changes with age have not been systematically evaluated. In the present study, relative and absolute numbers of CD34+, CD10+CD19+, and CD4+CD8+ cell subsets were determined in umbilical cord blood from 12 full-term normal newborns, 43 children aged 1 month to 6 years, and 10 young adults. The samples were processed by whole-blood lysis and monoclonal antibody staining, and cells were analyzed by flow cytometry. Immature cells were present in cord blood and progressively declined in both absolute and percentage numbers with age, each according to a particular curve, reaching youth values roughly at age 2-4 years. These results demonstrate that phenotypically immature cells normally circulate at low levels in peripheral blood, mostly at birth and during infancy, but also during youth.
Asunto(s)
Linfocitos B/clasificación , Células Madre Hematopoyéticas/clasificación , Linfocitos T/clasificación , Adulto , Antígenos CD/análisis , Antígenos CD34/análisis , Linfocitos B/inmunología , Niño , Preescolar , Células Madre Hematopoyéticas/inmunología , Humanos , Inmunofenotipificación , Lactante , Recién Nacido , Linfocitos T/inmunologíaRESUMEN
A method for quantifying the cellularity of rats bone marrow per unit of weight is described. Absolute numbers of each cell type per mg of bone marrow in the left and right femurs of the same experimental animal were determined at different times. In normal rats in which both femurs were studied simultaneously it was found that the absolute counts of each cell type per mg of bone marrow in the left and right femurs did not differ, nor were differences found in absolute numbers of marrow cells when the quantitative analyses from the left femurs were compared with those of the right femurs of the same animal, 10 and 20 days later. In order to test the validity of the present method for evaluating the effects of drugs on hematopoiesis, a single oral dose of busulphan (20 mg/kg), was administered to normal rats immediately after the marrow quantitative studies of the left femurs were performed. A marked and significant reduction in total nucleated cell was seen in marrows from the right femurs, 10 days later. Cellular effects were particularly pronounced on the myeloid line. Results presented here indicate that the quantitative study employed is a simple and useful method to evaluate the effects of drugs on hematopoiesis. The novelty of this method lies in: 1) its expression of cellularity on a per mg marrow basis, thereby avoiding possible misinterpretations of data which occur when results are expressed as percentages and 2) the analysis of contralateral femoral marrow specimens obtained from the same animal before and after drugs treatment. Therefore, each animal acts as its own control avoiding possible errors in the determination of drug-induced hematopoietic changes due to inter-animal variability.
Asunto(s)
Células de la Médula Ósea , Examen de la Médula Ósea/métodos , Busulfano/farmacología , Hematopoyesis/efectos de los fármacos , Animales , Médula Ósea/efectos de los fármacos , Fémur , Células Madre Hematopoyéticas/clasificación , Células Madre Hematopoyéticas/efectos de los fármacos , Masculino , RatasRESUMEN
Se describe un método que permite cuantificar la celuradidad de la médula ósea de la rata por unidad de peso. A tal efecto se determinaron en diferentes tiempos los números absolutos de cada tipo celular presentes en el fémur derecho e isquierdo del mismo animal de experimentación y los resultados se expresan en número de células por mg de médula ósea. En la rata normal se demostró que el número absoluto de cada tipo celular por mg de médula ósea es muy similar en el fémur derecho e izquierdo. Esto ocurre cuando el estudio de la celularidad medular se realiza simultáneamente en ambos huesos, y también cuando se comparan los resultados del estudio cuantitativo del fémur izquierdo con los del fémur derecho del mismo animal con 10 y 20 días de intervalo. Con el objeto de ratificar la validez del método para el estudio de la acción de drogas sobre la hematopoyesis medular, se observaron, además, los efectos de una dosis de busulfán (20 mg/Kg, vía oral), administrada inmediatamente después de que se realizó el estudio cuantitativo de la celularidad de la médula ósea del fémur izquierdo de una rata normal. Los resultados se compararon con los obtenidos de la médula ósea del fémur derecho de los mismos animales, 10 días después. Se demostró una marcada y significativa disminución del total de células nucleadas por mg de médula ósea, luego de ese período de observación. Los efectos celulares del busulfán fueron particularmente intensos sobre la progenie mieloide de médula ósea, con una reducción del
Asunto(s)
Ratas , Animales , Masculino , Hematopoyesis/efectos de los fármacos , Médula Ósea/citología , Examen de la Médula Ósea/métodos , Busulfano/farmacología , Médula Ósea/efectos de los fármacos , Fémur , Células Madre Hematopoyéticas/clasificación , Células Madre Hematopoyéticas/efectos de los fármacosRESUMEN
Se describe un método que permite cuantificar la celuradidad de la médula ósea de la rata por unidad de peso. A tal efecto se determinaron en diferentes tiempos los números absolutos de cada tipo celular presentes en el fémur derecho e isquierdo del mismo animal de experimentación y los resultados se expresan en número de células por mg de médula ósea. En la rata normal se demostró que el número absoluto de cada tipo celular por mg de médula ósea es muy similar en el fémur derecho e izquierdo. Esto ocurre cuando el estudio de la celularidad medular se realiza simultáneamente en ambos huesos, y también cuando se comparan los resultados del estudio cuantitativo del fémur izquierdo con los del fémur derecho del mismo animal con 10 y 20 días de intervalo. Con el objeto de ratificar la validez del método para el estudio de la acción de drogas sobre la hematopoyesis medular, se observaron, además, los efectos de una dosis de busulfán (20 mg/Kg, vía oral), administrada inmediatamente después de que se realizó el estudio cuantitativo de la celularidad de la médula ósea del fémur izquierdo de una rata normal. Los resultados se compararon con los obtenidos de la médula ósea del fémur derecho de los mismos animales, 10 días después. Se demostró una marcada y significativa disminución del total de células nucleadas por mg de médula ósea, luego de ese período de observación. Los efectos celulares del busulfán fueron particularmente intensos sobre la progenie mieloide de médula ósea, con una reducción del
Asunto(s)
Ratas , Animales , Masculino , Busulfano/farmacología , Examen de la Médula Ósea/métodos , Hematopoyesis/efectos de los fármacos , Médula Ósea/citología , Fémur , Células Madre Hematopoyéticas/clasificación , Células Madre Hematopoyéticas/efectos de los fármacos , Médula ÓseaRESUMEN
O autor apresenta um sucinto relato a respeito da formaçäo das células do sangue, enfatizando dados referentes ao sistema de Stem cells hematopoéticas, fatores humorais e tissulares associados à diferenciaçäo e maturaçäo celulares e sobre o microambiente medular