Biomedical subjects

M Schmelczer

Publications and source records attributed to M Schmelczer.

7 recordsLinked to original sources

PubMed1979

Platelet turnover and megakaryocytopoiesis in ITP.

Among patients with ITP, a group of 9 subjects displayed a reduced platelet turnover. In their bone marrow the megakaryocyte mass was measured by 59Fe, and the results were referred to those of 6 patients with a moderately increased and of 6 with a considerably increased platelet turnover. In the low-turnover group the megakaryocyte nuclear lobe number was subnormal cells with basophil cytoplasm were in the majority and the number of megakaryocytes was increased, whereas in the other two groups of megakaryocite population showed a shift to the right, and increased nuclear lobe number, and the number of megakaryocytes, related to the erythroid cells, was increased. It is therefore assumed that in the case of a reduced platelet turnover, the megakaryocytes are damaged, primarily their maturation in the bone marrow. The three groups showed, however, no clinical differences.

Adult↗

PubMed1978

Production and life-span of platelets and of fibrinogen in acute leukaemia. 75Se-selenomethionine- and 51Cr (Na-chromate)-studies.

The life-span of platelets and of fibrinogen was studied by the use of 75Se-selenomethionine and 51Cr in 28 cases of acute leukaemia (AL), and in 2 cases of chronic myelocytic leukaemia with blast-cell transformation. The patients were grouped on the basis of clinical remission or activity. In all groups, whether examined by means of 75Se or 51Cr, a reduction of variable degree was found in platelet life-span, and platelet turnover was reduced in the majority of the cases. The sequestration data were atypical. Simultaneous 75Se studies for platelet and fibrinogen life-span revealed a latent diffuse intravascular coagulation (DIC) in three cases, the process being still in progress in one case and in remission in two cases at the time of observation. Fibrinogen life-span was reduced in some of the cases. Thrombocytopenia in AL is attributed to a complex origin in which infiltration of the bone marrow, the destructive effect of antimetabolic therapy, abnormally increased consumption of storage of the functionally impaired platelets, possibly latent DIC or episodic excessive sequestration may be equally involved. Remission may be accompanied by normalization of both thrombopoiesis and platelet kinetics.

Adolescent↗

PubMed1978

Immune thrombocytolytic purpura (ITP): a diagnostic and therapeutic survey of 86 cases with regard to the results of splenectomy and conservative therapy.

The therapeutic results in 86 cases of ITP seen over a period of 15 years are reported. Distribution of the haemorrhagic manifestations was in agreement with published data. On follow-up of the 40 splenectomized patients, the shortened platelet life-span, the reduced "recovery" as well as the increased rates of platelet turnover and platelet formation revealed a manifest tendency of normalization. One year after splenectomy the results were found "good" or "moderate" in 86%, more than two years after the intervention in 85%, of the cases. Retrospective analysis of the platelet-sequestration studies having shown "good" or satisfactory results in 93% of the splenic cases, this investigation is regarded as crucial to the indication of splenectomy. The absence of increased thrombocytopoiesis in approximately 15% of the cases is attributed to an antibody effect, reflected in a reduced polyploidy of the megakaryocytes. Normalization or increase in platelet count early after splenectomy is interpreted as a favourable prognostic sign. On the other hand, neither age of the patients nor the time of splenectomy was found to affect the success of the intervention. The results of corticosteroid treatment (Prednisolon 52%) lag far behind those of splenectomy. Ten patients were given combined immunosuppressive treatment.

Adolescent↗

PubMed1978

Comparative immunological studies in ITP.

Twelve splenectomized and 16 non-splenectomized patients with ITP were studied for autoimmune complement fixation (AICF), indirect immunofluorescence (IF), platelet "immuno-injury" (T-3), antinuclear antibody (ANA), and serum electrophoresis. AICF was found positive in 50%, IF in 81%, T-3 in 50%, ANA in 69% of splenectomized cases. No significant difference in any of above parameters or in the gamma globulin levels was found between the splenectomized and the non-splenectomized groups. These observations are less favourable than those reported by other workers in post-splenectomy cases of ITP. The results, in agreement with those of earlier lymphocyte-transformation studies of the authors, are consistent with the primary mechanical role of the spleen in ITP, and make it justified to connect the failure of ITP to respond adequately to splenectomy, and the persistent seropositivity in these cases, with an excessive IgG production by the bone marrow.

Adolescent↗

PubMed1976

Platelet storage in the spleen in idiopathic thrombocytopenic purpura and congestive splenomegaly.

The kinetics of 51Cr-tagged platelets was studied in 10 patients with idiopathic thrombocytopenic purpura and in 8 patients with congestive splenomegaly. The surgically removed spleens were examined for their platelet content and for their microscopic structure. In idiopathic thrombocytopenic purpura the life-span of platelets was reduced, the number of platelets washed out from the spleen averaged 4.36 X 10(10)/100 g splenic tissue (intrasplenic platelet reserve). The index platelets per g splenic tissue/platelets per ml whole blood reflecting the tendency of platelets to concentrate in the spleen was 8.06. Microscopically, extensive phagocytosis of platelets by macrophages and a preserved lienal architecture were seen. In the group of congestive splenomegaly the life-span of platelets was not significantly shortened and the intrasplenic platelet reserve agreed with the figure found in idiopathic thrombocytopenic purpura. The spleen was characterized by fibroid degeneration and endothelial hypertrophy causing partial obstruction of the sinusoids. It is concluded that while the intrasplenic platelet reserve is nearly the same in idiopathic thrombocytopenic purpura and congestive splenomegaly, in idiopathic thrombocytopenic purpura hypersequestration while in congestive splenomegaly platelet storage predominates.

Adolescent↗

PubMed1976

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.

Bone Marrow↗

PubMed1975

The use of 75selenomethionine for labelling the formed and protein elements of the blood.

In the introduction the authors describe the biological role of platelets, plasma protein, fibrinogen and erthrocytes as well as the methods of tagging, separating and measuring them. The advantage of platelet labelling with 75selenomethionine is that it allows production and life-span to be determined simultaneously, however, the in vivo measurements do not give information on the site of platelet sequestration. Protein anabolism as well as katabolism can be evaluated with it, and the simultaneous determination of platelet and fibrinogen turnover may be especially useful in pathological conditions. The determination of erythrocyte life-span with 75 selenomethionine does not give so much information as the 59Fe and 51Cr methods, but when used for the examination of cell kinetics in combination with the latter methods it may afford an insight into erythropoiesis. The biological and the effective half-life periods (Teff) of 75selenomethionine are probably shorter than indicated in the literature.

Blood Cells↗