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Biomedical subjects

K Konstantopoulos

Publications and source records attributed to K Konstantopoulos.

At least 55 records · Page 3Linked to original sources
PubMed1997

Erythropoietin levels and microcytosis in heterozygous beta-thalassaemia.

Erythropoietin levels were determined in 50 Greek females: 20 beta-thalassaemia (beta-thal) heterozygotes, 15 with a diagnosis of iron-deficiency anaemia and 15 normal controls. In beta-thal trait carriers, the erythropoietin levels were slightly higher than in normal controls (16.65 +/- 4.43 vs. 12.84 +/- 2.47 mU/ml); these levels were significantly lower than those in iron-deficient subjects with the same degree of anaemia (55.24 +/- 31.35 mU/ml). In both groups, the erythropoietin levels are statistically correlated with the severity of anaemia (r = -0.537 p < 0.05 for iron deficiency; r = -0.610 p < 0.01 for beta-thal heterozygotes). In beta-thal heterozygotes, a close inverse correlation with red cell number and erythropoietin levels was also noted. It is suggested that microcytosis accompanying beta-thal trait constitutes an additional factor intervening in the regulation of erythropoiesis.

Adult↗
PubMed1997

HLA-A and -B antigens and larynx carcinoma in Greeks.

The frequency of HLA antigens in 30 Greek larynx carcinoma patients was more prominent for the A21, A28 and B17 antigens compared to 400 healthy unrelated controls from the same population. It is suggested that immunogenetic factors may contribute to the pathogenesis of this neoplasia.

Adult↗
PubMed1997

Detection of "PNH red cell" populations in hematological disorders using the Sephacryl Gel Test micro typing system.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal disorder characterised by an unusual sensitivity of abnormal red cell population(s) to complement lysis, due to a complete or incomplete defect of various surface molecules, including CD55 and CD59. PNH has been associated with various hematological disorders. Using a newly introduced method, the Sephacryl gel test microtyping system, we investigated the presence of CD55 or CD59 defective red cell populations in several hematological disorders. It was also found that a large proportion of such patients possess CD55 deficient populations, while a smaller but still significant proportion possess CD59 deficient populations. Defective red cell populations were detected in normal subjects as well. These findings need further investigation. Nevertheless the Sephacryl Gel Test microtyping system although non specific, seems to be useful in screening for the PNH and/or "PNH-like" red cell defect in several hematological disorders.

CD55 Antigens↗
PubMed1997

Leukaemia cutis preceding acute myelomonocytic leukaemia.

We report a case of acute myelomonocytic leukaemia (AMML) who presented with a striking leukaemic infiltration in the frontal area of the scalp that was also rapidly followed by infiltrates in other sites of the skin, mainly in the upper thoracic wall. Leukaemic skin infiltration developed independently of his haematological status; nevertheless, he rapidly progressed to acute leukaemia. We emphasise the importance of early recognition and identification of such lesions with a subsequent early application of systematic antileukaemic therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Intraerythrocytic 2,3-diphosphoglycerate concentration in hypertensive subjects before and following control by anti hypertensive treatment.

METHODS: We measured the 2,3-diphosphoglycerate inraerythrocytic concentration in 24 normal controls and in 24 hypertensives before and following drug therapy. RESULTS: In hypertensives the 2,3-diphosphoglycerate concentration was higher than that of the controls (14.96 mumol/g Hb vs 13.26 mumol/g Hb respectively); the difference is statistically significant (p < 0.001). Following control of the hypertension by drug therapy, the 2,3 DPG levels in the patients studied do not seem to differ statistically from those of the controls. CONCLUSIONS: This may be a consequence of lower cardiac output in hypertension which results to a lower tissue perfusion, leading to an increased concentration of deoxygenated haemoglobin in the vein blood. Measurement of 2,3-diphosphoglucerate may prove of value in estimating tissue perfusion in hypertension.

2,3-Diphosphoglycerate↗
PubMed1996

Development of plasma cell tumors during treatment of multiple myeloma.

Plasma cell tumors (plasmacytomas-PCT) of the bone, or extramedullary PCT, may be diagnosed in patients with or without the diagnostic criteria for systemic multiple myeloma (MM). The reason for the local development of these tumors is not clear. Recent reports emphasize the contribution of CT and MRI in the detection of bone lesions and their expansion into the soft tissues. We report the development of PCT in nine patients with MM under maintenance treatment with alpha-IFN, of whom six had no evidence of systemic relapse and three had indications of early relapse. The PCT were located in the pelvis (4), thoracic (3), cervical (1), and lumbar (2) spine and in 8/9 cases were not demonstrable on plain X-rays. These observations suggest that frequent screening with advanced imaging techniques may detect local disease expansion in asymptomatic patients. Early application of radiochemotherapy may improve prognosis.

Adult↗
PubMed1996

HLA antigens and asthma in Greeks.

HLA-A and -B antigens were determined in a group of 76 Greek asthmatic patients: 35 children (1.5-15 years) and 41 adults (18-73 years). The results were compared to those of 400 healthy unrelated controls from the same population. The standard NIH lymphocytotoxicity test was applied. When all 76 patients were compared to the controls, a statistically significant lower frequency of HLA-B5 and -B35 antigens was noted. When adults were analysed alone, an increased frequency of HLA-B8 was found. On the other hand, in the asthmatic children sub-group, the HLA-A10 antigen was significantly higher and the HLA-B5 was significantly lower than in the controls. These data imply that different HLA antigens may be involved in the pathogenesis of several clinical forms of asthma and that, in order to study the role of immunogenetic factor(s) in the pathogenesis of this disease, more adequate grouping criteria are needed.

Adolescent↗
PubMed1996

Expression of insulin-like growth factor-I receptor and transferrin receptor by breast cancer cells in pleural effusion smears.

Smear preparations were made from cells harvested from pleural fluid from 90 patients with breast cancer and stained for transferrin receptor (TRFr) and insulin-like growth factor-I receptor (IGF-Ir) using an immunocytochemical technique. The results were correlated with those from 36 benign effusions smears. In malignant smears from the breast cancer cases TRFr was demonstrated in 84.4% of the cellular deposits and IGF-Ir in 91.1%. TRFr was demonstrated in two (11%) of the tuberculous effusion smears and in six (100%) effusions from patients with collagen disease. IGF-Ir was not demonstrated in any of the smears from patients with benign disease. The sensitivity and specificity of TRFr staining were 84.4% and 77.7%, respectively, and for IGF-Ir staining were 91.1% and 100%, respectively. The underlying metabolic changes in the tumour cells which give rise to positive staining with these markers are discussed.

Adenocarcinoma↗
PubMed1996

Selective IgA deficiency in a patient with Hashimoto's thyroiditis. Case report.

We describe a case of Hashimoto's thyroiditis in which, eight years after initial diagnosis, an isolated (selective) IgA deficiency was detected. It is not clear which of these two conditions followed the other (both aetiologically and chronologically); indications and arguments for and against both hypotheses are discussed.

Adult↗
PubMed1996

DNA haplotypes in Africans and West Indians with sickle cell anaemia or SC disease.

Considering that genetic variation linked to the beta S mutation may influence the clinical manifestations of sickle cell disease, we have analyzed the beta globin cluster haplotypes in 47 patients with this condition (33 SS homozygotes, one S/beta thal (0), and 13 SC) living in London (30 West Indian, 17 West African). Of the 80 chromosomes tested, 82.5% had the Benin haplotype and of the 13 C chromosomes tested, 85% had the Bantu-A4 haplotype. A minority of patients had Bantu or Senegal haplotypes, and in 5 patients we found new haplotypes called E, H and O which may have arisen through mutation or recombination. Because of the predominance of a single haplotype (Benin) nearly all our homozygous S patients were either homozygous or heterozygous for this haplotype. We concluded that the beta globin haplotype is unlikely to be an important determinant of the clinical severity in this patient population.

Africa, Western↗
PubMed1995

Shear-induced platelet aggregation is inhibited by in vivo infusion of an anti-glycoprotein IIb/IIIa antibody fragment, c7E3 Fab, in patients undergoing coronary angioplasty.

BACKGROUND: Elevated levels of shear stress such as those that occur in stenotic arterial vessels can directly activate and aggregate platelets and thus contribute to the pathogenesis of acute arterial thrombosis. This shear-induced platelet aggregation (SIPA) is mediated by von Willebrand factor binding to platelet membrane glycoprotein (GP) Ib and GPIIb/IIIa. The chimeric Fab fragment of the monoclonal antibody 7E3 (c7E3 Fab) that binds selectively to GPIIb/IIIa is under clinical evaluation in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). This study was undertaken to investigate the effects on ex vivo SIPA of c7E3 Fab administered to patients undergoing PTCA. METHODS AND RESULTS: Six patients received aspirin (325 mg) and boluses of heparin (12,00o U) followed by c7E3 Fab 0.25 mg/kg. Blood collected from each patient before and after heparin treatment and at various time points after c7E3 Fab administration was subjected to laminar shear stress in a cone-and-plate viscometer. Flow cytometry was used to quantify the extents of platelet aggregation and of antibody binding to GPIIb/IIIa. Results indicate that c7E3 Fab injection resulted in a rapid, extensive blockade of GPIIb/IIIa receptors (98.6 +/- 0.2%) and a 50% inhibition of ex vivo platelet aggregation induced by shear stress. c7E3 Fab also completely abolished the formation of large platelet aggregates ("large" refers to particles > 10 microns in equivalent sphere diameter), which are presumably the aggregates of greatest clinical significance. Partial reversibility of the inhibition was noted within 2 days after drug administration, but even after 1 week, platelet function had not been fully restored. CONCLUSIONS: This study demonstrates that c7E3 Fab is a potent inhibitor of SIPA, which may be an important mechanism of its beneficial effect in the treatment of arterial occlusive diseases and in the prevention of thrombotic complications of coronary artery disease after angioplasty.

Abciximab↗
PubMed1995

Hb Lepore (Pylos)/Hb S compounds heterozygosity in two Greek families.

We have studied three compound heterozygotes for Hb Lepore ("Pylos")/HbS hemoglobin, a combination quite uncommon in the literature. It is of interest that while two of these cases are clinically similar to those thus far reported, the third one is free of symptoms and the diagnosis was put incidentally. This mild condition may be due to the high level of fetal hemoglobin produced.

Adult↗