RESUMEN
Dorsal vessel morphogenesis in Drosophila melanogaster serves as a superb system with which to study the cellular and genetic bases of heart tube formation. We used a cardioblast-expressed Toll-GFP transgene to screen for additional genes involved in heart development and identified tailup as a locus essential for normal dorsal vessel formation. tailup, related to vertebrate islet1, encodes a LIM homeodomain transcription factor expressed in all cardioblasts and pericardial cells of the heart tube as well as in associated lymph gland hematopoietic organs and alary muscles that attach the dorsal vessel to the epidermis. A transcriptional enhancer regulating expression in these four cell types was identified and used as a tailup-GFP transgene with additional markers to characterize dorsal vessel defects resulting from gene mutations. Two reproducible phenotypes were observed in mutant embryos: hypoplastic heart tubes with misaligned cardioblasts and the absence of most lymph gland and pericardial cells. Conversely, a significant expansion of the lymph glands and abnormal morphology of the heart were observed when tailup was overexpressed in the mesoderm. Tailup was shown to bind to two DNA recognition sequences in the dorsal vessel enhancer of the Hand basic helix-loop-helix transcription factor gene, with one site proven to be essential for the lymph gland, pericardial cell, and Svp/Doc cardioblast expression of Hand. Together, these results establish Tailup as being a critical new transcription factor in dorsal vessel morphogenesis and lymph gland formation and place this regulator directly upstream of Hand in these developmental processes.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/anatomía & histología , Drosophila melanogaster/embriología , Corazón/embriología , Sistema Hematopoyético/embriología , Proteínas de Homeodominio/metabolismo , Morfogénesis/fisiología , Factores de Transcripción/metabolismo , Animales , Animales Modificados Genéticamente , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiología , Elementos de Facilitación Genéticos , Regulación del Desarrollo de la Expresión Génica , Corazón/anatomía & histología , Sistema Hematopoyético/anatomía & histología , Proteínas de Homeodominio/genética , Fenotipo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Factores de Transcripción/genética , TransgenesRESUMEN
The process of wing disc development and degeneration in the bagworm moth Eumeta variegata was investigated histologically. Morphological differences between two sexes first appear in the penultimate (eighth) larval instar. In the male, wing discs proliferate rapidly in the penultimate larval instar and continue proliferating; a conspicuous peripodial epithelium forms in the last (ninth) larval instar. The hemopoietic organs break down in this stage and disappear completely by the prepupal stage. In the female, in contrast, the wing discs remain as in the previous (seventh) instar, without proliferation of cells inside. No peripodial epithelium forms in the penultimate instar or later. Hemopoietic organs are still attached to the wing discs in the last larval instar and the entire wing discs transform into a plain, thick epidermis in the prepupal period. It is suggested that the hemopoietic organs may prevent the wing discs from developing in E. variegata.
Asunto(s)
Mariposas Nocturnas/anatomía & histología , Mariposas Nocturnas/crecimiento & desarrollo , Alas de Animales/anatomía & histología , Alas de Animales/crecimiento & desarrollo , Animales , Diferenciación Celular , Femenino , Sistema Hematopoyético/anatomía & histología , Técnicas Histológicas , Larva , Masculino , Morfogénesis , Caracteres SexualesRESUMEN
We have generated mice deficient in O6-methylguanine DNA methyltransferase activity encoded by the murine Mgmt gene using homologous recombination to delete the region encoding the Mgmt active site cysteine. Tissues from Mgmt null mice displayed very low O6-methylguanine DNA methyltransferase activity, suggesting that Mgmt constitutes the major, if not the only, O6-methylguanine DNA methyltransferase. Primary mouse embryo fibroblasts and bone marrow cells from Mgmt -/- mice were significantly more sensitive to the toxic effects of the chemotherapeutic alkylating agents 1,3-bis(2-chloroethyl)-1-nitrosourea, streptozotocin and temozolomide than those from Mgmt wild-type mice. As expected, Mgmt-deficient fibroblasts and bone marrow cells were not sensitive to UV light or to the crosslinking agent mitomycin C. In addition, the 50% lethal doses for Mgmt -/- mice were 2- to 10-fold lower than those for Mgmt +/+ mice for 1,3-bis(2chloroethyl)-1-nitrosourea, N-methyl-N-nitrosourea and streptozotocin; similar 50% lethal doses were observed for mitomycin C. Necropsies of both wild-type and Mgmt -/mice following drug treatment revealed histological evidence of significant ablation of hematopoietic tissues, but such ablation occurred at much lower doses for the Mgmt -/- mice. These results demonstrate the critical importance of O6-methylguanine DNA methyltransferase in protecting cells and animals against the toxic effects of alkylating agents used for cancer chemotherapy.
Asunto(s)
Alquilantes/toxicidad , O(6)-Metilguanina-ADN Metiltransferasa/genética , Animales , Antibióticos Antineoplásicos/farmacología , Antineoplásicos Alquilantes/farmacología , Carcinógenos/farmacología , Carmustina/farmacología , Dacarbazina/análogos & derivados , Dacarbazina/farmacología , Genotipo , Sistema Hematopoyético/anatomía & histología , Hígado/enzimología , Metilnitronitrosoguanidina/farmacología , Ratones , Ratones Noqueados , Mitomicina/farmacología , Modelos Biológicos , Estreptozocina/farmacología , TemozolomidaRESUMEN
PURPOSE: This study was made to clarify the paramagnetic effect of iron stored in the hematopoietic tissue of bone marrow. MATERIAL AND METHODS: The T1 and T2 relaxation times of bone-marrow water in the L1-3 vertebrae of 20 healthy individuals were measured by MR imaging with a 1.5 T magnet. The chemical shift misregistration effect was used to isolate the bone-marrow water. The results were compared with the serum ferritin concentration. RESULTS AND CONCLUSION: Although no correlation between the T1 relaxation rate of the water fraction and the serum ferritin concentration was evident, the T2 relaxation rate of the water fraction showed strong linear correlation with the serum ferritin concentration (r = 0.87, p < 0.0001). Thus, T2 of bone-marrow water accurately reflects the amount of iron in normal bone marrow. This finding may be useful in the evaluation of the characteristics of hematopoietic tissue in bone marrow.
Asunto(s)
Agua Corporal/química , Médula Ósea/química , Ferritinas/sangre , Hierro/análisis , Imagen por Resonancia Magnética , Adulto , Médula Ósea/anatomía & histología , Espectroscopía de Resonancia por Spin del Electrón , Femenino , Sistema Hematopoyético/anatomía & histología , Sistema Hematopoyético/química , Humanos , Vértebras Lumbares/anatomía & histología , Vértebras Lumbares/química , Masculino , Persona de Mediana EdadAsunto(s)
Neoplasias Hematológicas/veterinaria , Sistema Hematopoyético/anatomía & histología , Linfoma no Hodgkin/veterinaria , Plasmacitoma/veterinaria , Timoma/veterinaria , Animales , Carcinógenos , Cricetinae , Neoplasias Hematológicas/inducido químicamente , Neoplasias Hematológicas/patología , Neoplasias Hematológicas/virología , Sistema Hematopoyético/fisiología , Leucemia Experimental/inducido químicamente , Leucemia Experimental/patología , Linfoma no Hodgkin/inducido químicamente , Linfoma no Hodgkin/patología , Trasplante de Neoplasias , Plasmacitoma/inducido químicamente , Plasmacitoma/patología , Especificidad de la Especie , Timoma/inducido químicamente , Timoma/patología , Virus , Rayos XRESUMEN
The hemic system is examined to evaluate clinical signs referable to the hemic system, establish a data base, or monitor the course of disease processes. Clinical signs of hemic disorders include pale mucous membranes, icterus, hemorrhage, hemoglobinuria, and tachycardia. Compared to other species, ruminants have small red blood cells, respond to anemia by releasing stippled red blood cells, commonly become neutropenic during acute bacterial sepsis, and fail to develop marked neutrophilia or left shift in response to inflammation.
Asunto(s)
Médula Ósea/anatomía & histología , Sistema Hematopoyético/anatomía & histología , Rumiantes/anatomía & histología , Animales , Recuento de Células Sanguíneas/veterinaria , Bovinos/sangre , Cabras/sangre , Rumiantes/sangre , Ovinos/sangreRESUMEN
Haemopoiesis occurs in close physical contact with elements of the bone marrow stroma. This review examines some adhesion molecules which are expressed in haemopoietic environments. These molecules may act to maintain cell contact between haemopoietic progenitors and the cellular and extracellular matrix elements of the marrow stroma. A review is undertaken of several families of adhesion molecules and their ligands, including integrins, CD44, LEC-CAMs, CAMs and variant glycosylation patterns expressed by haemopoietic cells. Both CD44 and integrin receptors have been implicated in mediating important cellular interactions within the haemopoietic system and the significance of these and other molecules in haemopoiesis is discussed.
Asunto(s)
Hematopoyesis/fisiología , Secuencia de Aminoácidos , Animales , Células de la Médula Ósea , Moléculas de Adhesión Celular/fisiología , Tejido Conectivo/fisiología , Matriz Extracelular/fisiología , Enfermedades Hematológicas/fisiopatología , Factores de Crecimiento de Célula Hematopoyética/fisiología , Células Madre Hematopoyéticas/citología , Sistema Hematopoyético/anatomía & histología , Sistema Hematopoyético/embriología , Humanos , Integrinas/fisiología , Lectinas , Tejido Linfoide/anatomía & histología , Tejido Linfoide/embriología , Ratones , Ratones Mutantes , Modelos Biológicos , Datos de Secuencia Molecular , Técnicas de Cultivo de Órganos , Proteoglicanos/fisiología , Receptores Mensajeros de Linfocitos/fisiología , Vertebrados/fisiologíaRESUMEN
Ofrece al alumno los conocimientos histológicos pertinentes y hace hincapié en los nuevos hallazgos destacables de la biología celular, que sirven para comprender la estructura y función de las células, tejidos y órganos
Asunto(s)
Cartílago/ultraestructura , Epitelio/ultraestructura , Genitales Femeninos/ultraestructura , Genitales Masculinos/ultraestructura , Glándulas Endocrinas/ultraestructura , Histología , Músculos/ultraestructura , Ojo/ultraestructura , Piel/ultraestructura , Sistema Cardiovascular/ultraestructura , Sistema Digestivo/ultraestructura , Sistema Hematopoyético/ultraestructura , Sistema Linfático/ultraestructura , Sistema Nervioso/ultraestructura , Sistema Respiratorio/ultraestructura , Tejido Adiposo/ultraestructura , Tejido Conectivo/ultraestructura , Cartílago/anatomía & histología , Epitelio/anatomía & histología , Genitales Femeninos/anatomía & histología , Genitales Masculinos/anatomía & histología , Glándulas Endocrinas/anatomía & histología , Músculos/anatomía & histología , Ojo/anatomía & histología , Piel/anatomía & histología , Sistema Cardiovascular/anatomía & histología , Sistema Digestivo/anatomía & histología , Sistema Hematopoyético/anatomía & histología , Sistema Linfático/anatomía & histología , Sistema Nervioso/anatomía & histología , Sistema Respiratorio/anatomía & histología , Sistema Urinario/anatomía & histología , Tejido Adiposo/anatomía & histología , Tejido Conectivo/anatomía & histología , Técnicas Histológicas/instrumentación , Técnicas Histológicas/normasRESUMEN
Ofrece al alumno los conocimientos histológicos pertinentes y hace hincapié en los nuevos hallazgos destacables de la biología celular, que sirven para comprender la estructura y función de las células, tejidos y órganos
Asunto(s)
Histología , Sistema Digestivo/ultraestructura , Glándulas Endocrinas/ultraestructura , Sistema Respiratorio/ultraestructura , Sistema Cardiovascular/ultraestructura , Sistema Linfático/ultraestructura , Sistema Hematopoyético/ultraestructura , Genitales Femeninos/ultraestructura , Genitales Masculinos/ultraestructura , Ojo/ultraestructura , Piel/ultraestructura , Músculos/ultraestructura , Sistema Nervioso/ultraestructura , Tejido Adiposo/ultraestructura , Tejido Conectivo/ultraestructura , Cartílago/ultraestructura , /ultraestructura , Epitelio/ultraestructura , Sistema Digestivo/anatomía & histología , Glándulas Endocrinas/anatomía & histología , Sistema Respiratorio/anatomía & histología , Genitales Femeninos/anatomía & histología , Genitales Masculinos/anatomía & histología , Sistema Urinario/anatomía & histología , Ojo/anatomía & histología , Piel/anatomía & histología , Sistema Nervioso/anatomía & histología , Sistema Cardiovascular/anatomía & histología , Músculos/anatomía & histología , Sistema Linfático/anatomía & histología , Sistema Hematopoyético/anatomía & histología , Tejido Conectivo/anatomía & histología , Tejido Adiposo/anatomía & histología , Cartílago/anatomía & histología , /anatomía & histología , Epitelio/anatomía & histología , Técnicas Histológicas/instrumentación , Técnicas Histológicas/normasAsunto(s)
Hematopoyesis/fisiología , Sistema Hematopoyético/anatomía & histología , Sistema Inmunológico/anatomía & histología , Inmunidad/fisiología , Animales , Evolución Biológica , Sistema Hematopoyético/citología , Sistema Hematopoyético/fisiología , Humanos , Sistema Inmunológico/citología , Sistema Inmunológico/fisiologíaRESUMEN
Trends in modern histology have been reviewed. The role of evolutionary concepts (hypotheses) in analysis of experimental data has been stressed. Several problems of onto- and phylogenesis of hemopoiesis have been discussed. They include evolution of structure of hemopoietic system; origin of fibroblasts and correlation of hemal (mobile) and desmal (fixed) mesenchymal cells; immunological approaches to studies of evolution of hemopoietic cell.
Asunto(s)
Evolución Biológica , Histología/tendencias , Animales , Movimiento Celular , Fibroblastos/citología , Sistema Hematopoyético/anatomía & histología , Sistema Hematopoyético/inmunología , InvestigaciónRESUMEN
Lymphoid (lymphomyeloid) tissues in sturgeons (hybrid sturgeon, Huso huso X Acipenser ruthenus, and white Pacific sturgeon, A. transmontanus) were investigated by dissection, histology and transmission electron microscopy. The main lymphomyeloid tissues are the thymus, the spleen, the anterior part of the kidney, the meningeal myeloid tissue, the pericardial tissue and lymphoid masses of the intestine, especially in the spiral valve. The kidney is the main hemopoietic tissue. The meningeal tissue is bone marrow-like (myeloid), mainly granulopoietic, but it also contains lymphoid elements. The pericardial tissue is predominantly lymphoid. The pericardial tissue has a lymph node-like appearance. It seems to be the site of interaction between lymphocytes and vascular endothelium. The thymus contains cortex and medulla. The spleen, as in higher vertebrates, is differentiated into white and red pulp. The highly diversiform and well developed lymphoid tissues of sturgeons may serve as basis of efficient immune mechanisms.
Asunto(s)
Peces/anatomía & histología , Tejido Linfoide/anatomía & histología , Animales , Células Sanguíneas/citología , Sistema Hematopoyético/anatomía & histología , Intestinos/anatomía & histología , Riñón/anatomía & histología , Meninges/anatomía & histología , Pericardio/anatomía & histología , Bazo/anatomía & histología , Timo/anatomía & histologíaRESUMEN
Adequate evaluation of the effects of external radiation fields on the haematopoietic system often requires knowledge of the number of grams of active marrow which received specific radiation doses rather than the average dose to the entire active marrow. There are several published reports of the amount of active marrow in different bones expressed as fractions of the total active marrow in the body, but none in which the actual number of grams can be computed for the individual patient. In the present study the number of grams of active marrow in the individual bones of the head and torso of adults has been computed and expressed as percent of body weight. Differences between males and females are not significant. For the major bones of caucasians the standard deviations are less than 25%. Very limited data indicate that there may be a similar range for Japanese adults. Similar computations for children have not been attempted here because of the uncertainties in the necessary data on body proportions.
Asunto(s)
Peso Corporal , Médula Ósea/anatomía & histología , Sistema Hematopoyético/anatomía & histología , Adolescente , Adulto , Anciano , Médula Ósea/efectos de la radiación , Huesos/anatomía & histología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Dosificación Radioterapéutica , Gravedad EspecíficaAsunto(s)
Sistema Linfático/embriología , Ovinos/anatomía & histología , Animales , Animales Recién Nacidos , Sistema Hematopoyético/anatomía & histología , Sistema Hematopoyético/embriología , Sistema Hematopoyético/inmunología , Sistema Linfático/anatomía & histología , Sistema Linfático/inmunología , Ovinos/inmunologíaAsunto(s)
Hematopoyesis , Sistema Hematopoyético/anatomía & histología , Animales , Células de la Médula Ósea , Enfermedades de la Médula Ósea/patología , Adhesión Celular , Diferenciación Celular , Tejido Conectivo/fisiología , Células del Tejido Conectivo , Células Madre Hematopoyéticas/citología , Humanos , Ratones , Modelos Biológicos , RatasRESUMEN
Avian embryonic marrow is segregated into distinct erythropoietic and granulopoietic compartments. Within each compartment presumptive stem cells and immature blood cells establish intimate contact with their respective stromal cell. In this study we have examined one aspect of potential hematopoietic cell-stromal cell interaction by looking for the presence of intercellular junctions between these two elements. In previous studies, after aldehyde fixation, junctions were not observed, but after perfusion fixation with tannic acid-glutaraldehyde, pentilaminar junctions became evident. These junctions were most characteristically located in the intravascular erythropoietic compartment, but were also found in the extravascular granulopoietic compartment. Junctions frequently joined presumptive stem cells with sinusoidal endothelial cells as well as joining immature erythroblasts with sinusoidal endothelial cells; and less frequently, junctions connected adjacent erythroid cells. However, reticulocytes and erythrocytes were never seen to have formed junctions with any other type of cell. Similar junctions within the extravascular compartment connected contiguous reticular cells and also, on occasion, reticular cells with sinusoidal endothelial cells. Hematopoietic cell-reticular cell junctions were restricted to two classes of blood cells--extravascular presumptive stem cells and mast cells. There was no evidence of junctions connecting mature or maturing granuloid cells and any other cell type. The presence of intercellular junctions between immature blood cells and their respective stromal cells suggests that such interactions might play an important role in avian hematopoiesis. However, further work will be needed to determine if these junctions are merely adherence sites or whether they represent sites of intercellular communication. In either event, these junctions appear to reflect a mechanism whereby the marrow stroma could regulate erythroid maturation.
Asunto(s)
Médula Ósea/ultraestructura , Sistema Hematopoyético/ultraestructura , Uniones Intercelulares/ultraestructura , Animales , Médula Ósea/anatomía & histología , Embrión de Pollo , Sistema Hematopoyético/anatomía & histologíaAsunto(s)
Sistema Hematopoyético , Neoplasias Experimentales/patología , Animales , Cricetinae , Sistema Hematopoyético/anatomía & histología , Sistema Hematopoyético/patología , Histiocitoma Fibroso Benigno/patología , Humanos , Linfoma de Células B Grandes Difuso/etiología , Linfoma de Células B Grandes Difuso/patología , Linfoma no Hodgkin/etiología , Linfoma no Hodgkin/patología , Trasplante de Neoplasias , Plasmacitoma/patología , Virus 40 de los SimiosRESUMEN
Vascular architecture and the structure of the intestinal hematopoietic centers of two cyclostomes, the hagfish Eptatretus burgeri and the ammocoetes larva of Entosphenus reissneri, are compared. Blood cells of the hagfish are generated in hematopoietic nests that develop around intestinal veins established primarily for transport of absorbed nutrients. In ammocoetes, on the other hand, blood cells are generated in hematopoietic nests of the typhlosole, closely associated with venous sinusoids developing around the longitudinally oriented mesenteric artery of the typhlosole. A collateral vein of the mesenteric artery is completed in the typhlosole after metamorphosis. Since the spleen of higher vertebrates develops in relation to establishment of the collateral vein of the largest foregut artery, the intestinal hematopoietic nests of ammocoetes may be regarded as a model of the primitive form of the spleen of higher vertebrates. Hematopoiesis in the hagfish intestine is not related to establishment of a collateral vein; hence "primitive spleen" or "intestinal spleen" may be improper terms in reference to the intestinal hematopoietic tissue of the hagfish. Morphological characteristics of the hematopoietic nests of the two cyclostomes are essentially the same. Blood cells of these nests are generated in the intervenous tissue, supported by interstitial connective tissue cells and reticulin fibers. Granulated cells are the most common type in the primitive hematopoietic nests. No definitive erythrothrombocytopoiesis has been identified. Lymphocytes have not been observed in the hagfish; however, small lymphocytes have been observed in the vascular lumen of sinusoids around the hematopoietic nests of ammocoetes. These lymphocytes probably originate outside of the typhlosole.
Asunto(s)
Vasos Sanguíneos/anatomía & histología , Peces/anatomía & histología , Sistema Hematopoyético/anatomía & histología , Intestinos/anatomía & histología , Animales , Arterias/anatomía & histología , Capilares/anatomía & histología , Peces/crecimiento & desarrollo , Metamorfosis Biológica , Microscopía Electrónica , Venas/anatomía & histologíaRESUMEN
The haemopoietic organs of the catfish, Clarias gariepinus, and the Mozambique bream, Sarotherodon mossambicus, were studied. In both species the primary haemopoietic organs are the pronephros, the mesonephros and the spleen. The peritoneum and, particularly in catfish, the omentum are of secondary importance in haemopoiesis.