Pulmonary and systemic hemodynamics during hemorrhagic shock in baboons.
(73/100)
The pulmonary and systemic hemodynamic response to four hours of hemorrhagic shock and resuscitation has been studied in 17 baboons using both open and closed chest models. No pulmonary artery (PA) hypertension occurred during shock or resuscitation except for an increase in lft ventricular end diastolic pressure (LVEDP) secondary to intravascular volumee overload with Dextran. Pulmonary vascular resistance (PVR) increased during shock but returned to control levels with reinfusion of shed blood and correction of acidosis. PVR was moderately elevated following reinfusion of shed blood if acidosis was not corrected or if volum resuscitation was inadequate. No increase in gradients occurred between PA pressure and left atrial (LA) pressure or LVEDP and there was no gradients between small pulmonary vein and LA pressure. Arterial PO2 uniformly increased during shock and remained at or above control levels of reinfusion. Gross or histologic evidence of "congestive atelectasis" or "shock lung" was not observed. These observations suggest that in the subhuman primate, hemorrhage alone does not produce significant injury to the lung during shock or the immediate postresuscitation interval. Hemorrhage alone did not produce changes in the lung which would result in increased pulmonary microvascular hydrostatic pressure following appropriate resuscitation. (+info)
Cerebral blood flow and blood viscosity in patients with polycythaemia secondary to hypoxic lung disease.
(74/100)
Blood viscosity, cerebral blood flow (CBF) and cerebral oxygen carriage (CBF X arterial oxygen content) were measured in 12 patients with polycythaemia secondary to hypoxic lung disease. CBF and cerebral oxygen carriage were both significantly higher than in a comparative group of 20 patients with raised packed cell volumes and normal lung function. The patients with secondary polycythaemia then underwent venesection and their mean packed cell volume fell from 0.613 to 0.495. This led to a consistent reduction in blood viscosity, which fell by 44% at a low shear rate (0.67/s) and 33% at a high shear rate (0.91/s). CBF rose by 21% (p less than 0.01), but cerebral oxygen carriage did not significantly increase in the group as a whole. Four of the patients with secondary polycythaemia had complained of episodes of confusion before venesection, which improved considerably once the packed cell volume had been lowered. Headache was relieved in a further two patients and none of the subjects was adversely affected by venesection. It was not possible, however, to show a correlation between symptomatic improvement and an increase in cerebral oxygen carriage. (+info)
Listeria monocytogenes meningitis and decreased phagocytosis associated with iron overload.
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A patient with Listeria monocytogenes meningitis was found to have idiopathic haemochromatosis and monocytes with reduced phagocytic capacity. The phagocytic function recovered completely after a series of therapeutic phlebotomies. In-vitro iron had a deleterious effect on the phagocytic capacity of monocytes and granulocytes. These findings show that iron overload in the host can increase susceptibility to L monocytogenes infection not only by increasing the virulence of the organism but also by reducing the phagocytic capacity of the monocytes. (+info)
Effect of venesection on calf blood flow in polycythaemia.
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Calf blood flow at rest and during postocclusive reactive hyperaemia was measured using an electrocardiogram-triggered plethysmograph in 14 patients with polycythaemia (nine with primary disease and five with polycythaemia secondary to cyanotic heart disease) before and after a course of venesection. The mean packed cell volume was reduced from 0.57 to 0.47, and whole-blood viscosity fell by 50% at low shear rates. Venesection did not affect rest flow, but peak flow was increased by 18%. The increase in peak flow failed to compensate for the reduced haemoglobin content of the blood, calculated haemoglobin delivery being reduced by 23% at rest and 10% during reactive hyperaemia. These results indicate that while venesection improves blood viscosity, this does not necessarily lead to improved delivery of oxygen to the tissues. (+info)
Treatment of polycythaemia vera by radiophosphorus or busulphan: a randomized trial. "Leukemia and Hematosarcoma" Cooperative Group, European Organization for Research on Treatment of Cancer (E.O.R.T.C.).
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Between 1967 and 1978 a Phase III cooperative study was performed in polycythaemia vera (PCV) patients who had not been treated previously with any specific therapy other than phlebotomy. 293 patients were included and allocated at random for either radiophosphorus therapy (146) or busulphan treatment (147). Additional phlebotomies were indicated in both groups, to keep the haematocrit at 42-47%. 285 patients were evaluable after the study was completed, of whom 50% have an 8-year follow-up. Both groups were comparable with respect to age, clinical symptoms and haematological parameters immediately before randomization. The duration of the first remission and the overall survival were significantly better in the busulphan group. This difference remains significant after correction for differences between the two groups with respect to sex-ratio and phlebotomy before and the start of therapy. Busulphan induced a longer first remission (P less than 0.001) and a longer overall survival (P less than 0.02). (+info)
Idiopathic hemochromatosis: serum ferritin concentrations during therapy by phlebotomy.
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We report the case of a 54-year-old man who presented with symptoms of idiopathic hemochromatosis, an inherited disorder involving regulation of iron absorption. These symptoms usually do not appear until total body iron content reaches 15 g, about threefold normal. Therapy involves mobilization and removal of excess stored iron through weekly or twice-weekly phlebotomies of 500 mL, until the hemoglobin concentration becomes less than 110 g/L and remains there for several weeks, or until serum ferritin concentrations indicate that almost all the stored iron has been removed (ferritin less than 12 micrograms/L). Here, concentrations of ferritin in serum were used as an index to iron overload and removal of stored iron. We report changes in hemoglobin, serum ferritin, iron, and total iron-binding capacity during the course of removing by phlebotomy more than 20 g of iron from a patient with idiopathic hemochromatosis. (+info)
Pluripotent hemopoietic progenitors (CFU-GEMM) in polycythemia vera: analysis of erythropoietin requirement and proliferative activity.
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Pluripotent hemopoietic progenitors (CFU-GEMM) give rise to multilineage hemopoietic colonies in culture. We have examined the erythropoietin requirements of CFU-GEMM-derived erythroid progeny in patients with polycythemia vera (PV) and studied their proliferative activity by short-term exposure to 3HTdR. Mixed colonies with erythroid components were observed in all bone marrow and peripheral blood samples from patients with PV that were cultured without addition of exogenous erythropoietin. This response is consistent with previously reported growth patterns for CFU-E and BFU-E. The frequency of mixed colonies increased regularly when erythropoietin was added to the cultures. Short-term exposure of peripheral blood specimens to 3HTdR prior to plating yielded a reduction of the plating efficiency by 20%-70% when compared to cells that were not exposed to 3HTdR. The observation of cycling CFU-GEMM in PV contrasts with the usually quiescent behavior of CFU-GEMM in peripheral blood of normal individuals under steady-state conditions. These results support the view that the increased proliferative rate observed for CFU-GEMM may be responsible for the increased formation of blood cells in PV. (+info)
Effect of short-term protein deprivation on hemopoietic functions of healthy volunteers.
(80/100)
To ascertain the effects of protein deprivation on hemopoietic parameters in otherwise healthy subjects, three volunteers were placed on diets containing 0.15 g protein/kg body weight for 8 days followed in 2 mo by another 8-day study period during which they ingested their usual diets containing more than 0.9 g protein/kg body weight. Complete blood counts, serum protein determinations, and tests of in vitro and in vivo leukocyte chemotaxis were performed prior to and at the conclusion of each study period. Subjects were phlebotomized of 500 ml on day 7 of each study period. Twenty-four-hour urinary erythropoietin excretion rates were assayed just prior to and again postphlebotomy. Reticulocyte counts were performed at intervals up to 1 wk postphlebotomy. Some of these determinations were replicated during a subsequent study. The hemoglobin and hematocrits decrased slightly but significantly after 8 days on low protein diets. Erythropoietin excretion rates and reticulocyte responses to phlebotomy were also less marked while subjects were on protein depleted diets. Leukocyte chemotaxis, measured both in vitro and in vivo, was also markedly reduced while subjects were on protein-depleted diets. We conclude that 8 days of moderately severe protein deprivation significantly impairs erythropoiesis and leukocyte function in otherwise healthy individuals. (+info)