Influence of acute hemorrhage on erythrodieresis

Influence of acute hemorrhage on peritoneal and splenic macrophages function and NO production was studied. Interaction of peritoneal and splenic macrophages with autologous erythrocytes was examined the day after the hemorrhage. Concentration of nitrate ions: the stable metabolites of nitric oxide, was measured in peritoneal lavage, splenic cells suspension, blood, as well as in supernatant of peritoneal and splenic macrophages before and after hemorrhage. The data obtained suggest that splenic macrophages of intact rats are more active than peritoneal ones. After hemorrhage peritoneal macrophages activity increases, whereas splenic macrophages remain unchanged. Concentration of nitrate ions is significantly reduced after hemorrhage.     

Effect of venesection on calf blood flow in polycythaemia.

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.     

Intermittent hypoxia in patients with unexplained polycythaemia.

The aetiology of polycythaemia is unclear in up to 30% of patients. Twenty patients with unexplained polycythaemia were investigated to see whether they had an intermittent hypoxic stimulus to erythropoiesis that was undetected by conventional investigations for hypoxic secondary polycythaemia. Overnight polygraphic sleep studies showed that five patients had prolonged nocturnal hypoxaemia. Their arterial oxygen saturation was below 92%, the level at which appreciable hypoxic stimulation of erythropoiesis occurs, for 26-68% of the time for which they were studied. Considerable evidence is accumulating that intermittent hypoxia is a potent stimulus to erythropoiesis, and clinicians should consider the possibility of nocturnal hypoxia in patients with unexplained polycythaemia. Appropriate investigation will lead to the correct diagnosis of polycythaemia secondary to hypoxia in some cases previously regarded as idiopathic, and treatment may then be planned accordingly.     

Simultaneous occurrence of Hb C trait and polycythaemia vera

A slow abnormal haemoglobin was found in a 27 year-old Negro man who had polycythaemia vera. Chemical and structural analysis showed it to be Hb C. The oxygen affinity showed a normal P50 value. Clinical and haematological investigations are described and discussed.     

Identity of the abnormal F-group chromosome associated with polycythaemia vera

Summary A technique for the identification of individual chromosomes has been applied to bone marrow cells from 4 patients with polycythaemia vera. These patients were already known to have the abnormal F-group chromosomes which occur in about 20% of cases of this disease. In each individual the particular chromosome involved was found to be a number 20, from which some material had been deleted, probably from the long arm.

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Zusammenfassung Eine Technik für die Identifikation einzelner Chromosomen wurde auf Knochenmarkzellen von 4 Patienten mit Polycythaemia Vera angewandt. Von diesen Patienten wußte man bereits, daß sie die abnormen F-Chromosomen besitzen, die in ungefähr 20% der Fälle dieser Krankheit vorkommen. Bei allen 4 Patienten stellete sich heraus, daß das spezielle Chromosom die Nr. 20 hat; es bestand jeweils eine Deletion, wahrscheinlich des langen Armes.

     

Changes in erythropoiesis during the course of polycythaemia vera.

Using 58Fe, 51Cr and cytological parameters, the authors have examined erythropoiesis in 44 polycythaemia vera patients diagnosed as such on the basis of the usual parameters (exept for determination of the erythropoietin level). In the patients divided into four types the following characteristica were observed. In type I, increased erythropoiesis is evident by accelerated plasma iron clearance, greater PIT and EIT as well as enhanced iron utilization and production indices. In type II, in addition to the former signs of increased erythropoiesis moderately shortened red cell life-span and hyposideraemia characteristic of splenic sequestration and resulting from bleeding and blood letting seem to be accompanied by microcytosis. There is a metaplastic erythropoiesis in type III, bone marrow activity decreases, but the increased erythropoiesis is indicated by several parameters already observed earlier. At the time the iron utilization indicative of effective erythropoiesis is decreased, thus ineffective erythropoiesis and considerably shortened red cell life-span are responsible for the enhanced iron turnover. This is also shown by the regression calculations. In type IV effective erythropoiesis was considerably decreased in the patients with severe anaemia. Sings which are indicative of metaplastic erythropoiesis are absent. In one of the patients the morphological changes characteristic of dyserythropoiesis were found. Although all our patients were given treatment. We believe that these alterations in the character of erythropoiesis are not likely to be the consequences of therapy.     

Pruritus and severe iron deficiency in polycythaemia vera.

Six patients diagnosed as having polycythaemia vera had severe pruritus that persisted despite adequate haematological control. Iron supplementation was given when iron deficiency was noted in all six patients. The pruritus began to improve two to 10 days after the start of treatment and had completely disappeared after two to three weeks. In three patients the iron treatment was stopped because of unacceptably high haemoglobin concentrations; the pruritus recurred. Since chronic iron treatment may result in increases in red cell mass indiscriminate use of iron in patients with polycythaemia vera and pruritus is not advocated. Nevertheless, in patients with severe symptoms and evidence of iron deficiency treatment with iron, continuing for two to three weeks after the symptoms have abated, may be beneficial.     

Role of the kidneys in the mechanism of erythrodieresis in hemolytic (phenylhydrazine) and acute posthemorrhagic anemia]

The degree of hemolysis was studied comparatively in intact and nephrectomized rats after the phenylhydrazine injection. In the nephrectomized animals hemolytic (phenylhydrazine) anemia was expressed by a lesser reduction of the total erythrocyte count, of the percentage of Cr51-labeled erythrocytes, and of the intensity of the reaction for hemosiderin in the organs and tissues. A lesser degree of erythrodieresis was found in the nephrectomized rats and after an acute unsubstituted blood loss. Blood perfusion through the kidney of anemic rats led to increase of the potassium concentration in the plasma perfusate, reduction of the electrophoretic mobility of erythrocytes, their resistance, hemolysis duration, and to decrease of albumin fractions with the mol wt of from 74 500 to 27 000 in the erythrocyte stroma.     

THe dynamics of erythropoiesis inhibition in posttransfusion polycythaemia in the rat

The dynamics of erythropoiesis inhibition as the consequence of polycythaemia induced in rats by four to six transfusions of homologous erythrocytes was studied in detail. It was found, that, in rats with polycythaemia elicited by two transfusions of erythrocytes, erythropoiesis inhibition occurs 67h after the first transfusion and it is most pronounced in the period between 115-187 h. The hemopoietic system is not completely free from the inhibitory influence of polycythaemia up to 283 h after the first transfusion. Maintenance of a state of polycythaemia for 17 days by repeated transfusions strongly and durably inhibits the haemopoietic system. The red blood cell system remained for this whole period under the inhibitory effect.