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K Konstantopoulos

Publications and source records attributed to K Konstantopoulos.

90 records · Page 5Linked to original sources
PubMed1991

HLA antigens and bronchogenic carcinoma in the Greek population.

The distribution of HLA antigens was studied in 85 Greek patients with bronchogenic carcinoma. Fifty-seven specific HLA antisera were used to determine 27 HLA-A and B antigens, with the two-stage standard NIH microlymphocytotoxicity assay. The results were compared with those in a control group, consisting of 400 healthy individuals. In the whole group of patients there was a significantly higher frequency of HLA-AW19 and HLA-A29 (p less than 0.003 and p less than 0.006 respectively) and a lower frequency of HLA-A2 and HLA-A3 (p less than 0.014 and p less than 0.006 respectively) than in the control population. In patients with squamous cell carcinoma there was a significantly higher frequency of HLA-AW19 and lower frequency of HLA-A2 (p less than 0.02 and p less than 0.05 respectively). In small cell carcinoma patients there was a significantly lower frequency of HLA-A3 (p less than 0.04) than among the controls. In patients with adenocarcinoma no significant change of HLA antigen frequencies was observed when compared to the controls.

Adenocarcinoma↗
PubMed1990

A study of beta-thromboglobulin and platelet factor-4 plasma levels in steady state sickle cell patients.

To evaluate the platelet function in sickle cell syndromes we measured the beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) plasma values of 45 patients suffering from homozygous sickle cell anaemia (10) and sickle cell beta-thalassaemia (35) in steady state. The results were compared to those of 32 normal controls. Both the beta-TG and PF-4 levels were found to be significantly higher in patients than in controls but the beta-TG:PF-4 ratio was significantly lower in the patients group. This finding and the absence of any statistical correlation between platelet number and beta-TG or PF-4 indicate that platelets seem to be somehow activated in sickle cell syndromes, both in homozygotes and sickle cell/beta-thalassaemia heterozygotes. This platelet activation seems to exist even in steady state sickle cell disease patients, regardless of the functional status of the spleen.

Adolescent↗
PubMed1989

Tropical pyomyositis in a Greek adult.

A case of tropical pyomyositis in a 24-year-old Greek is reported. The patient presented with high fever and swelling of the left thigh, generalized lymphadenopathy and multiple infiltrations in both lung fields on X-ray of the chest. Multifocal muscle abscesses were detected by CT scan of the left thigh and gluteal area. Staphylococcus aureus was identified in cultures of the purulent material which was surgically drained. The patient was subsequently treated with appropriate antibiotics. Lack of familiarity with this disease caused diagnostic confusion and delayed the initiation of treatment.

Adult↗
PubMedDate not supplied

Shear stress-induced binding of von Willebrand factor to platelets.

Shear stress-induced platelet aggregation requires von Willebrand factor (vWF), platelet glycoprotein (GP) Ib, GPIIb-IIIa, Ca2+, and adenosine diphosphate (ADP). Recent reports using vWF labeled with either 125I or fluorescein isothiocyanate (FITC) have demonstrated that in shear-fields, vWF binds to both GPIb and GPIIb-IIIa. The sequence of the vWF finding to the two platelet receptors has not been precisely determined in these reports. In this study, a flow cytometry technique using a primary anti-vWF antibody and a secondary FITC IgG antibody was used to measure shear stress-induced vWF binding to platelets. Washed normal platelets suspended at 50,000/microliters with purified large vWF multimers were exposed to laminar shear stresses of 15 to 120 dynes/cm2 for 30 sec. At this low platelet count, little or no aggregation occurred in the shear fields. A significant increase in post-shear vWF-positive platelets was consistently observed. Experiments with platelets from normal and severe von Willebrand's disease (vWD) (which lack plasma and platelet alpha-granule vWF) demonstrated that exogenous vWF predominately contributed to the platelet-vWF binding. Blockade of platelet GPIb with the monoclonal anti-GPIb antibody, 6D1, completely inhibited shear stress-induced platelet-vWF attachment. In contrast, blockade of GPIIb-IIIa with monoclonal anti-GPIIb-IIIa antibodies, 10E5, or c7E3, or with the GPIIb-IIIa-blocking tetrapeptide, RGDS had little or no inhibitory effect on platelet-vWF binding. These data demonstrate that the binding of vWF to GPIb is likely to be the initial shear-induced platelet-ligand binding event.

Blood Platelets↗
PubMedDate not supplied

Acute bone marrow aplasia associated with intravenous administration of deferoxamine (desferrioxamine).

The authors report the clinical course and fatal outcome of a case of acute bone marrow aplasia, after intravenous administration of deferoxamine (desferrioxamine) to a 16-year-old girl with homozygous beta-thalassaemia. The type of aplasia was mainly that of a megakaryocytic thrombocytopenia, but the 2 other haemopoetic series were also involved. The absence of any other toxic factors and the quite rapid onset of the bone marrow failure after this type of treatment strongly suggest that intravenous administration of high doses of deferoxamine was the potential toxic factor.

Adolescent↗
PubMedDate not supplied

Flow cytometric studies of platelet responses to shear stress in whole blood.

The objective of this work was to evaluate quantitatively the effects of flow on platelet reactions using a flow cytometric technique. Whole blood was exposed to well defined, laminar shear stress in a cone-and-plate viscometer in the absence of added agonists. Blood specimens were fixed with formaldehyde and incubated with two monoclonal antibodies. Antibody 6D1, specific for platelet membrane glycoprotein Ib (GPIb), was used to identify and enumerate platelets and platelet aggregates on the basis of their characteristic forward scatter and 6D1-FITC fluorescence profiles. Anti-CD62 antibody, specific for the granule membrane protein-140 (GMP-140), was used to measure platelet activation. Results showed platelet aggregation increasing with increasing shear stress with marked increase in this response for a pathophysiological stress level of 140 dyn/cm2 and higher. This stress level also was the apparent threshold for formation of large platelet aggregates ("large" refers to particles larger than 10 microns in equivalent sphere diameter). These platelet responses to shear stress were insensitive to aspirin, but strongly inhibited by agents that elevate platelet cyclic adenosine monophosphate (cAMP) levels. Moreover, pre-incubation of whole blood with monoclonal antibodies that inhibit von Willebrand factor binding to GPIb or von Willebrand factor and fibrinogen binding to GPIIb/IIIa inhibited platelet aggregation. Aggregation induced by shear at 37 degrees C was less in extent than at 23 degrees C. At physiological shear stresses, whole blood was more susceptible to shear-induced platelet aggregation than platelet-rich plasma. This study reaffirms that flow cytometric methods have several important advantages in studies of shear effects on platelets, and extends the methodology to whole blood unaltered by cell separation methods.

Adult↗
PubMedDate not supplied

A case of spinal cord compression by extramedullary haemopoiesis in a thalassaemic patient: a putative role for hydroxyurea?

We report a case of homozygous beta thalassaemia who developed chronic paraparesis due to spinal cord compression by paravertebral extramedullary masses. Our patient was successfully treated with hypertransfusion and hydroxyurea. This drug in addition to its well-known cytostatic effects, may be a good alternative in conditions analogous to our case. This action of hydroxyurea can also be attributed to its favourable effect on foetal haemoglobin production.

Adult↗
PubMedDate not supplied

Survival, hospitalization and cause of death in 99 patients with the myelodysplastic syndrome.

Survival, causes of death and hospitalization have been studied in 99 patients with the myelodysplastic syndrome. The median survival of the patients was 702 days, and the 10 year actuarial survival only 10 per cent, which is not significantly better than the corresponding figures in the remission stage of AML. Although MDS-patients who developed acute leukemia had significantly (p less than 0.05) more platelets, they also had significantly (p less than 0.05) more major bleeding as a contributory cause of death than patients who did not develop leukemia. Bleeding seems to be diagnosed only in 12 per cent in vivo, whereas major bleeding is found at autopsy in 38 per cent of the patients. The patients who did not develop leukemia died significantly (p = 0.018) more often of cardiovascular causes. MDS patients spend one sixth of their remaining life in hospital, on an average. This is true both for those who develop leukemia and for those who do not. The terminal hospital stay lasts an average of 24 days, which is comparable to the figure for myeloma.

Follow-Up Studies↗
PubMedDate not supplied

Asplenia in systemic lupus erythematosus: a simple coincidence?

Two patients with asplenia and systemic lupus erythematosus are described. Both patients presented with unusual symptoms of the disease. The possible association of asplenia, presumably congenital, and systemic lupus erythematosus is discussed.

Antibodies, Antinuclear↗
PubMedDate not supplied

Recovery of carbimazole-induced agranulocytosis following recombinant granulocyte-macrophage colony stimulating factor (rhGM-CSF) administration.

A 56 year old female patient treated with carbimazole for hyperthyroidism developed agranulocytosis complicated by pneumonia. She was treated by sc administration of 6 micrograms/kg rhGM-CSF for 10 days. The first neutrophils appeared in the peripheral blood on the 4th day and normal numbers are reached on the 7th day of treatment. This was accompanied by a rapid resolution of fever. The use of growth factors may be justified in cases of drug-induced agranulocytosis.

Agranulocytosis↗
PubMedDate not supplied

Deferoxamine treatment during early pregnancy: absence of teratogenicity in two cases.

We report two cases of transfusion-dependent thalassemia treated by deferoxamine during the first trimesters of two successful pregnancies. The absence of any sign(s) of toxicity or teratogenicity is remarkable; despite the data from animal models, it seems that deferoxamine in humans is rather harmless for the fetus at the usually recommended doses.

Abnormalities, Drug-Induced↗