Erythropoiesis and erythrophagocytosis in bovine haemal nodes / Eritropoyesis y eritrofagocitosis en nodos linfáticos hemales de bovino

Whether bovine haemal nodes are involved in turnover of red blood cells has been a subject of some controversy In this study, fluorescent and conventional optical microscopy of conventionally or immunohistochemically stained node sections, together with transmission electron microscopy, showed the presence of erythrocyte precursors and megakaryocytes, and evidence of active involvement in the destruction and replacement of old or degenerate red cells and the platelets.

Si nodos linfáticos hemales bovinos están involucrados en la cantidad de volumen de glóbulos rojos ha sido objeto de cierta controversia. En este estudio, secciones de nodos linfáticos teñidas convencionalmente o inmunohistoquimicamente fueron analizadas con microscopía óptica fluorescente y convencional, junto con microscopio electrónico de transmisión, los que revelaron la presencia de precursores eritrocíticos y megacariocitos, y la evidencia de participación activa en la destrucción y sustitución de glóbulos rojos viejos o degenerados y plaquetas.

Inhibition of rats extramedullary liver erytropoiesis by hyperbaric oxygen therapy

PURPOSE: To research the hyperbaric oxygen therapy effects on rats' livers and spleens. METHODS: 30 adult male Hotzman rats were used, being randomly distributed, by raffle, into 2 groups of 15 animals each: group 1 - control; group 2 - hyperbaric oxygen therapy. Group-2 animals underwent hyperbaric oxygen therapy for 120 minutes daily, 90 minutes of which were under pressure of 2.5 atmospheres. The first and last 15 minutes were used for gradual compression and decompression, respectively, for 20 days in a row. The livers and spleens of the animals from the two groups were taken out for histologic examination, on the day after the end of hyperbaric oxygen therapy in group 2 animals. Liver and spleen histologic changes of the animals from the two groups were compared by using Fisher exact test. P < 0.05 was regarded as a significant difference. RESULTS: The only change in liver and spleen histology was the significant reduction in hepatic extramedullary erythropoiesis in the animals that underwent hyperbaric oxygen therapy (p < 0.05). CONCLUSION: Hyperbaric oxygen therapy reduces hepatic extramedullary erythropoiesis in rats and doesn't jeopardize the other liver and spleen structures.

OBJETIVO: Pesquisar os efeitos da oxigenoterapia hiperbárica sobre o fígado e baço de ratos. MÉTODOS: Foram utilizados 30 animais machos adultos da espécie Holtzman, distribuídos aleatoriamente e por sorteio em dois grupos de 15 animais cada, assim designados: grupo 1 - controle; grupo 2 - oxigenoterapia hiperbárica. Os animais do grupo 2 foram submetidos à oxigenoterapia hiperbárica por 120 minutos ao dia, sendo 90 minutos sob pressão de 2,5 atmosferas e 15 minutos iniciais e finais para a compressão e descompressão gradativa, respectivamente, em 20 dias consecutivos. Os fígados e baços dos animais dos dois grupos foram retirados para exame histológico, no dia seguinte após o término da oxigenoterapia hiperbárica nos animais do grupo 2. Compararam-se as alterações na histologia do fígado e baço entre os animais dos dois grupos empregando-se o teste exato de Fisher, considerando diferença significante o valor de p<0,05. RESULTADOS: A única alteração na histologia dos fígados e baços foi a redução significativa da eritropoiese extramedular hepática nos animais submetidos a oxigenoterapia hiperbárica. (p < 0,05) CONCLUSÃO: A oxigenoterapia hiperbárica reduz a eritropoiese extramedular hepática em ratos e não compromete as demais estruturas do fígado e do baço.

Efeitos da eritropoetina recombinante humana em recém-nascidos pré-termo com doenças infecciosas / Effects of recombinant human erythropoietin in preterm newborns with infectious diseases

OBJETIVO: Analisar os efeitos da eritropoetina recombinante humana (rHuEpo) em recém-nascidos pré-termo com doenças infecciosas graves. MÉTODOS: Foi realizado um estudo controlado, não randomizado, em 34 recém-nascidos com diagnóstico de patologias infecciosas graves, peso de nascimento igual ou inferior a 1500 g, idade gestacional inferior a 35 semanas e estabilidade clínica. Os recém-nascidos designados para o tratamento com rHuEpo receberam a eritropoetina ß na dose de 400 UI/kg, duas vezes por semana, por via subcutânea. A suplementação oral com ferro foi iniciada quando os níveis de ferritina sérica foram inferiores a 60 mcg/L. O estudo foi realizado durante seis semanas ou até a alta hospitalar do paciente. Foram avaliados a eritropoese, o número de transfusões, o número de neutrófilos, a contagem de plaquetas e os episódios de novas infecções durante o tratamento com o hormônio. RESULTADOS: Houve aumento significativo do número de reticulócitos no grupo tratado; entretanto, não houve impacto sobre o número ou volume de transfusões. Não foram observadas alterações no número de neutrófilos ou plaquetas. CONCLUSÃO: O uso de rHuEpo em RNPT com doenças infecciosas, na dose de 800 UI/Kg/semana, foi efetivo para induzir eritropoese, sem ocorrerem alterações significativas sobre o número de neutrófilos ou plaquetas. Essa estratégia, associada ao controle rigoroso do volume de sangue retirado para exames, poderá ser benéfica na prevenção da anemia em RNPT com infecção grave.

OBJECTIVE: To study the effects of recombinant human erythropoietin (rHuEpo) in preterm newborns (PTNs) with serious infectious diseases. METHODS: A not randomized case-control study was carried out in 34 preterm newborns with diagnosis of serious infectious pathologies, gestational age up to 35 weeks, birth weight less than 1500 g and clinical stability. Newborns selected for treatment with rHuEpo received 400 U/kg erythropoietin ß, subcutaneously twice a week. Oral iron supplementation was initiated when the levels of serum ferritin were lower than 60 mcg/l. The study was continued for six weeks or until the patient was discharged from the hospital. Erythropoiesis, granulopoiesis, thrombocytopoiesis, the need for transfusions and the occurrence of new episodes of infectious disease were analyzed. RESULTS: In the treated group there was a significant increase in the number of reticulocytes, although there was no statistically significant difference between the groups with regard to the number or volume of transfusions. There was no significant difference in neutrophils and platelet values. CONCLUSION: The use of rHuEpo, 800 U/kg/week, in PTNs with infectious diseases was effective in inducing erythropoiesis, without significant changes in the number of neutrophils or platelets. This strategy, and the accurate control of the blood collected for laboratory exams, may be beneficial for prevention of the anemia in PTNs with serious infectious diseases.

Influencia de la altura en la eritropoyesis del recien nacido / Influence of the height in erythropoiesis newborn

Objetivo. Estudio de la influencia de la hipoxia de la altura sobre la eritropoyesis del recien nacido através del análisis de valores hematológicos. Población. Trescientas muestras de sangre venosa de cordon umbilical de niños nacidos vivos a término y 300 muestras de sangre venosa periférica de mujeres gestantes del Hospital de la Mujer de La Paz a 3600 msnm. Métodos. Los estudios se realizaron con contador automatico Micros 60 y por técnicas manuales. Resultados. Los valores hematológicos de las gestantes normales comparados con sus similares habitantes a nivel del mar son estadísticamente diferentes; mientras que los valores hematológicos de los recien nacidos en la altura comparados con los del nivel del mar, son estadísticamente similares. Conlusión. La eritropoyesis de los recien nacidos en la altura es independiente de los factores maternos y del ambiente hipóxico presente a 3600 msnm, probablemente por la función protectora que ejerce la placenta.

Expected value of serum soluble transferrin receptor, erythropoietin and ferritin and their correlation among healthy non-anemic Thai children.

Transferrin receptor (TfR) is a glycoprotein which mediates the entry of ferric transferrin from the extracellular compartment into the cells. The measurement of sTfR has become a widely used tool in assessing erythropoiesis but its use has mainly been restricted to research laboratory settings. In Thailand, there are only a few reports concerning the sTfR. The authors studied the expected value of sTFR as well as other basic parameters for monitoring of erythropoiesis as erythropoietin (EPO) and ferritin among a sample of non-anemic healthy Thai children. In addition, correlation was done between each pair of studied parameters. Expected range for sTfR level for the healthy controls in this study was 1.761 to 2.034 mg/L. Expected range for serum EPO level for the healthy controls in this study was 19.445 to 34.176 mU/ml. Expected range for serum ferritin level for the healthy control from this study was 67.895 to 96.692 ng/ml. Of interest, poor correlation among the three studied parameters, sTfR, serum EPO and serum ferritin was observed in this study.

Defective Erythropoiesis in Bone Marrow is a Mechanism of Anemia in Children with Cancer

Evaluation of the mechanism of anemia in cancer patients might help to select patients for the more efficient use of erythropoietin (EPO, a growth factor for erythroid precursor cells). For this, we investigated whether the production of EPO responds to anemia and the bone marrow responds to EPO appropriately, and whether chronic inflammation is inhibitory to erythropoiesis in anemic cancer children. Serum levels of EPO, soluble transferrin receptor (sTfR), tumor necrosis factor (TNF)-alpha, and erythrocyte sedimentation rate (ESR) in anemic cancer children were measured by enzyme-linked immunosorbent assay and then the correlation coefficients between those parameters and hemoglobin (Hb) were determined. Both in leukemia and in solid tumor patients, there were significant inverse correlations between Hb and EPO (leukemia: tau=-0.547, p<0.0001; solid tumor: tau=-0.591, p<0.0001), and between sTfR and EPO (leukemia: tau=-0.223, p<0.05; solid tumor: tau=-0.401, p<0.05). In contrast, sTfR showed a correlation with Hb in leukemia (tau=0.216, p<0.05) but not in solid tumor patients. sTfR was suppressed in 53% of anemic episodes of leukemia and 78% of those of solid tumor patients. Our results suggest that in cancer children, the EPO production is not defective and chronic inflammation is not inhibitory to erythropoiesis. Rather, the defective erythropoiesis itself is thought to be responsible for the anemia.

Erythropoietin requirement for the maintenance of normal levels of erythropoiesis in the normal adult mouse

Erythropoietin (EPO) is a glycoprotein which appears as the primary regulator of erythropoiesis under either normal or most of the pathologic conditions. In the rat with experimentally-reduced erythropoiesis, daily administration of 1.3 IRP units can restores the function and maintain steady-state conditions of red cell formation. This important information for the programming of both physiologic and pharmacologic studies is lacking for the mouse, in spite of the fact that most of the experiments performed on the regulation of erythropoiesis have been conducted in this species. In the present study, designed to determine EPO requirement for maintenance of steady-state erythropoiesis in the adult mouse under standard laboratory conditions, adult females of the CF#1 strain were exposed to hypobaria (18h/day) durring a 3-week period for induction of polycythemia (P). At the end of the hypoxic period, P mice were maintained at sea level conditions, as were normocythemic (N) mice during the entire experimental period. P mice were daily injected with 0,0.5, 1.0, 1.5, or 2.0 IRP units of rHu-EPO during the 4-day period that followed the hypoxic one. The rate of erythropoiesis in N and P mice were measured by RBC(-59) Fe uptake. The plasma (59)Fe half-clearance time was also measured in other groups of N and P mice similarly treated. One-way ANOVA showed that the only non-significant difference (P>0.05) between N and EPO-injected P mice was established for the 1.0 unit dose group. It is thus suggested that approximately 1.0 unit of EPO should be synthesized aily in an adult mice to maintain a normal rate of erythropoiesis.

Proliferative and maturative behaviour patterns on murine bone marrow and spleen erythropoiesis along hypoxia

The present study was performed to determine quantitative and qualitative effects of hypoxia on murine erythron, CF1 mice were submitted to hypobaric hypoxia (HH) along 18 days. The proliferative response to recombinant human erythropoietin (rHuEPO: 0-250 mU/ml) was analyzed by DNA assays from bone marrow and spleen cells at different times. Bone marrow proliferative response showed a slight increment under stress but remained over control by the end of the experience. Splenic erythroid proliferative response was observed at a maximum rate on day 6 of HH (26 fold) and returned near to control values after day 10. The assessment of erythropoietic maturative pattern was performed by 59Fe uptake assays. Total nuclear cell counts increased in both tissues (1.5 times in marrow and 5 times in spleen) under hypoxia. In addition, percentages of different lineages (erythroid, myeloid and lymphoid) were scored. Total erythroid marrow cell counts increased in a narrowly degree and persisted above basal counts after day 18. Meanwhile, splenic red cells rose to 30 times over control on day 6 and failed sharphy near control values from day 12 of HH. Splenic red cells contribution was approximately 60 percent of total production between 6-8 days. By the end of the assay bone morrow took back erythroid command (90 percent). These findings indicate correlation between the time course as well as quantitative and qualitative parameters in the patterns of proliferation and maturation. Moreover, the erythron response to hypoxia, seemed to be related to microenvironmental regulations rather than to hormonal variances.

Bioquimica de la eritropoyetina / Biochemistry of erithropoyetin

Se revisan los factores involucrados en la regulacion normal de la eritropoyesis, los principales acontecimientos historicos en el conocimiento a cerce de la eritropoyetina y su papel en la estimulacion y regulacion de la eritropoyesis, la estructura molecula, mecanismos de accion, tecnicas de laboratorio para su determinacion, valores normales en sangre y orina, metabolismo, produccion renal y extrarenal y sus implicaciones clinicas tanto en las anemias como en las policitemias.

Murine splenic proliferative response to human recombinant erythropoietin along hypoxia

La hipoxia constituye el mejor stress fisiológico para la pertubación del estado estacionario eritropoyético. El present estudio tiende a analizar la respuesta proliferativa eritropoyética esplénica con diferentes dosis de eritropoyentina humana recombinante bajo condiciones hipóxicas a lo largo 18 días mediante el ensayo de síntesis del DNA. Los progenitores esplénicos normóxicos no sufren proliferación eritroide significativa al día 0. Una clara respuesta proliferativa a rh Epo se verificó entre los 2 y 8 días de hipoxia. La proliferación de los progenitores eritroides esplénicos hipóxicos retornó a un patrón basal desde los 10 días hasta el final de la experiencia. La mayor creatividad proliferativa, 25 veces sobre el control (p<0.001), se produjo a los 6 días de condicionamiento desde 62.5 hasta 250mU/ml de rh Epo. estos resultados son concordantes con el concepto que durante la daptación fisiológica a la hipoxia, las células progenitoras eritroides esplénicas modifican transitoriamente su tasa proliferativa observable por variaciones en la relación dosis-respueta a Epo

Efectos de la osteosíntesis medular sobre la eritropoyesis / Effects of medular osteosynthesis on erithropoiesis

Una preocupación general de los ortopedistas al colocar un clavo intramedular consiste en la lesión de la médula ósea, lo que pudiera afectar la eritropoyesis. Con el propósito de revisar lo anterior, los autores efectuaron osteosíntesis con clavo Colchero intramedular con pernos en 39 pacientes con 23 fracturas (8 de fémur y 15 de tibia), 15 no uniones (3 de fémur y 12 de tibia) y una dismetría congénita de tibia. Para saber si la lesión de la médula ósea afectaba o no la eritropoyesis, se analizó en cada uno de los pacientes el comportamiento de los reticulocitos, precursores de los eritrocitos, encontrando que no sólo no hubo alteración en estas células, sino un aumento en los 15 primeros días, volviendo después a la normalidad. El estudio se dividió en tres etapas: prequirúrgica, quirúrgica y posquirúrgica, ésta última con un seguimiento de 15, 30, 60 y 90 días. Se añadió un grupo control de 60 personas no fracturadas.

Patterns of erythropoiesis and anaemia in malaria.

Of 138 patients with malaria, 90 were found to be having Plasmodium falciparum in their peripheral blood smears. Megaloblastosis alone or in combination with the other patterns of erythropoiesis was observed in 82.1 percent cases of chronic P. falciparum malaria as compared to 36.3 and 26.5 per cent cases of acute P. falciparum and P. vivax malaria respectively. Iron deficiency was observed in 15.5 percent cases of chronic P. falciparum, 18.2 per cent cases of acute P. falciparum and 13.3 per cent patients of P. vivax infection. Of patients with chronic falciparum malaria, 33.3 percent revealed features of both megaloblastosis and defective iron utilization and transient hypoplasia of marrow was observed in 8.9 per cent of these cases.

Efeito da castraçäo sobre o volume globular em Rattus novergicus machos / Castration effect on globular volume in Rattus novergicus males

Foram castrados exemplares machos de Rattus novergicus em idade pós-púbere para avaliar o efeito dos androgênios sobre a eritropoiese. O volume globular foi monitorado por treze dias. O grupo controle de machos mostrou uma média de 45,16 ñ 0,75%, o grupo controle de fêmeas 44,21 ñ 0,97%, o grupo experimental de machos castrados 41,25 ñ 1,25% (p<0,05) no sexto dia e 42,80 ñ 0,80% no décimo terceiro dia (p<0,05); o grupo exerimental de castrados ñ 1,25% (p<0,05) no sexto dia e 42,80 ñ 0,80% no décimo terceiro dia (p<0,05); o grupo experimental de castrados tratados com testosterona apresentou um média de 43,40 ñ 1,47% no décimo terceiro dia pós-castraçäo. Esses achados mostram a importância dos androgênios na eritropoiese