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Biomedical subjects

M Freund

Publications and source records attributed to M Freund.

At least 145 records · Page 8Linked to original sources

Cross-reactivity of human molecular markers for detection of prethrombotic states in various animal species.

The aim of the present study was to investigate the reactivity of immunoreagents developed for clinical applications in humans in different animal species (hen, mouse, rat, rabbit, guinea-pig, dog, pig, sheep, baboon). Prothrombin fragment 1 + 2, thrombin-antithrombin III complex and fibrinopeptide A were tested for coagulation, platelet factor 4 and beta-thromboglobulin for platelet activation, glycoprotein IIb-IIIa, glycoprotein Ib and P-selectin for platelet membrane glycoproteins, D-dimers for fibrinolysis, thrombomodulin for activation of endothelial cells and thrombospondin and von Willebrand factor for adhesive proteins. Prothrombin fragment 1 + 2, platelet factor 4, beta-thromboglobulin and D-dimers were revealed only in baboons. Fibrinopeptide A was well detected in baboons but weakly in mice, dogs, pigs and sheep. Whereas glycoprotein IIb-IIIa was revealed on guinea-pig, dog and sheep platelets and glycoprotein Ib on rabbit and dog platelets, P-selectin and thrombomodulin were never detected. Thrombospondin was revealed in hens, mice, rats, guinea-pigs, pigs, sheep and baboons and von Willebrand factor in mice, rats, guinea-pigs, dogs, pigs, sheep and baboons. Interestingly, thrombin-antithrombin III complex (TAT) was detected in all species tested except the hen. A time- and dose-dependent increase in TAT was observed when rats, dogs or pigs were infused with thromboplastin (4.5-450 microliters/kg/h), while administration of hirudin (1 mg/kg) abolished this TAT generation. Thus, the TAT immunoassay could provide a tool for the screening of antithrombotic drugs in a number of animal species. However, the possibility of using a wider panel of human immunoreagents would appear to be restricted to baboons which display good species cross-reactivity.

Animals↗

Neonatal stroke involving the middle cerebral artery in term infants: clinical presentation, EEG and imaging studies, and outcome.

Six children with neonatal cerebral infarction of the middle cerebral artery are reported. Seizures or respiratory distress were the initial symptoms. In some cases abnormal findings appeared earlier on EEG than on ultrasound. The EEG changes were concordant with the localization of the lesion. Ultrasound examinations revealed an echodense structure within the vascular territory, after a phase of appearing to be normal, highly suggestive of cerebral infarction. The diagnosis was confirmed by CT scan. Findings on EEG, cranial ultrasound and CT suggested that the stroke represented a late intra-uterine event. At long-term follow-up, six children had failed to develop normally for age and had become obviously hemiplegic as gross motor development proceeded. Four of the patients had developed epilepsy. These data indicate that the outcome of neonatal stroke may not be as positive as previously reported.

Brain↗

Effect of recombinant human interferons in inducing differentiation of acute megakaryoblastic leukaemia blast cells.

The effects of interferons (IFN)-alpha, beta 2 and -gamma in inducing megakaryocytic differentiation of blast cells from a patient with acute megakaryoblastic leukaemia (AMegL) was investigated in liquid suspension culture by the increase in CD41 and CD42b expressions using monoclonal antibodies in the APAAP technique. After six days of culture, the percentage of CD41 and CD42b positive cells increased in control cultures from 15.2% and 10.6% on day 0 to 32.0 +/- 4.3% and 22.1 +/- 2.5%, respectively. The addition of IFN-alpha significantly increased the number of CD41 and CD42b positive cells by about two to three fold compared to control cultures (p < 0.01) and by about four to six fold compared to day 0 (p < 0.001) Similarly, IFN-beta 2 induced a significant increase in CD41 and CD42b positive cells. On the other hand, IFN-gamma failed to increase the number of CD41 and CD42b positive cells in comparison to control cultures on day 6 and instead stimulated a significant increase in the number of monocytes/macrophages by about ten fold compared to control cultures in IFN-gamma-treated cultures (p < 0.001). The present results suggest that megakaryocytic differentiation of blast cells in AMegL could be induced by IFN-alpha and beta 2 and support a clinical role for them in the treatment of AMegL patients. Also, the present results showed that monocytic differentiation of blast cells in AMegL could be stimulated by IFN-gamma, supporting the multipotent stem or progenitor cell origin of the AMegL subtype of acute myelogenous leukaemia.

Aged↗

17p anomalies in lymphoid malignancies: diagnostic and prognostic implications.

Eighteen patients with lymphoid malignancies and abnormalities of the short arm of chromosome 17 were evaluated, in order to analyse whether this anomaly was associated with a particular subgroup of lymphoid malignancies. The patients suffered from acute lymphoblastic leukemia, high-grade non-Hodgkin's lymphoma or plasma cell leukemia. No 17p anomaly was found in any patient with chronic lymphocytic leukemia or low-grade non-Hodgkin's lymphoma. In four cases the aberration of the short arm of chromosome 17 was the sole cytogenetic abnormality, in fourteen patients additional chromosomal aberrations were found. Five out of 18 cases were Burkitt's lymphoma/leukemia showing the typical rearrangement of 8q24. In cases with a karyotype evolution the 17p anomaly was always a late event. Concerning the clinical outcome of the patients with abnormalities of the short arm of chromosome 17 eight of nineteen patients died within 90 days after the diagnosis of the 17p anomaly only three were alive at the last follow up (26 months to 40 months after diagnosis of a 17p aberration). Rearrangements of 17p, especially as secondary cytogenetic events, seem to be associated with a poor clinical outcome in lymphoid malignancies.

Adolescent↗

A new fibroblast growth stimulating activity from the human megakaryoblastic leukaemia cell line ELF-153: in vitro and in vivo findings.

Although the exact mechanism for the progression of myelofibrosis in acute megakaryoblastic leukaemia is unclear, certain humoral factors released from the proliferating megakaryoblasts that are unable to store these factors in their defective alpha-granules, including platelet derived growth factor (PDGF), fibroblast growth factors (FGF), platelet factor-4 (PF-4), transforming growth factor-beta (TGF-beta) and beta-thromboglobulin, could result in increased collagen synthesis by bone marrow fibroblasts. Recently, the human megakaryoblastic leukaemia cell line MEG-01 has been shown to produce both TGF-beta and PF-4 which have enhanced the growth of bone marrow fibroblasts. Therefore, we have examined the presence of a fibroblast growth stimulating activity and the humoral factors that might be responsible for it in the supernatant of the human megakaryoblastic leukaemia cell line ELF-153 recently established in our laboratory from a patient with acute myelofibrosis. A new fibroblast growth stimulating activity has been identified in the supernatant of the ELF-153 human megakaryoblastic leukaemia cell line that is independent of the percentage of fetal calf serum in NRK-49F fibroblast agar clonogenic assays and is not due to any of the known fibroblast growth stimulating humoral factors including PDGF, epithelial growth factor, TGF-alpha or beta, tumour necrosis factor-alpha, interleukin-1, 2, 4 or 6, FGF, fibronectin, PF-4 and factor VIII AG. Also, in vivo, subcutaneous injection of ELF-153 megakaryoblastic leukaemia cells into nude mice formed, in three out of the five mice after 6 weeks, subcutaneous tumours with a very rigid texture whose histological examination revealed dense infiltration by blast cells and pronounced reticular fibrosis. Immunohistochemistry demonstrated exclusive deposition of collagen III in the extracellular matrix whereas laminin and collagen IV were absent.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Arab population data on the PCR-based loci: HLA-DQA1, LDLR, GYPA, HBGG, D7S8, Gc, and D1S80.

Allele and genotype frequencies for seven polymerase chain reaction (PCR)-based DNA genetic markers were determined in an Arab sample population. The loci analyzed were HLA-DQA1, LDLR, GYPA, HBGG, D7S8, Gc and D1S80. Results were obtained from the first six loci using the AmpliType HLA-DQ alpha DNA and AmpliType PM PCR Amplification and Typing Kits. The VNTR locus D1S80 PCR product was analyzed by polyacrylamide electrophoresis and silver staining. All loci meet Hardy-Weinberg expectations. The frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a DNA profile in the Arab population.

Alleles↗

[Prenatal diagnosis of spontaneous thrombosis of the umbilical artery during the third trimester of pregnancy. Two cases with surviving infants].

Thrombosis of the umbilical artery was diagnosed in utero in two cases at the echography examination performed during the third trimester of gestation. The infants were born live and in good health. This is the first report of such antenatal diagnosis. The lack of prospective studies hinder the evaluation of fetal morbidity and mortality. Nevertheless, umbilical artery thrombosis is a high risk obstetrical situation since the potential risk of another thrombus in the second umbilical artery would lead to fetal death in utero. Careful monitoring is required with extraction of the fetus as soon as term allows or whenever the elements compromise fetal development.

Adult↗

[CT angiographic imaging of atypical arterial blood supply to the liver by the superior mesenteric artery].

Variations of the celiac trunk are seen in 25-35% of all patients. In 10-12% the right hepatitic artery arises from the superior mesenteric artery, the left hepatic artery in 4-5%. An aberrant origin of the common hepatic artery is seen in about 2.5%. We report about a patient with liver cell adenoma, in whom we diagnosed preoperatively the atypical origin of the common hepatic artery by performing CT angiography in the MIP technique (MIP = Maximum Intensity Projection). Conventional angiography as well as intraoperative findings confirmed the diagnosis.

Adenoma, Liver Cell↗

G-CSF in the long-term treatment of cyclic neutropenia and chronic idiopathic neutropenia in adult patients.

Eleven adult patients with chronic neutropenia have been treated with recombinant human granulocyte colony-stimulating factor (G-CSF). Seven patients had idiopathic sporadic neutropenia, 2 idiopathic congenital neutropenia and 2 cyclic neutropenia. Treatment was started with 3 micrograms/kg s.c. daily and was modified according to response. All patients had a rapid increase of neutrophils. The cycle length shortened from 21 to 14 days in patients with congenital cyclic neutropenia. Doses required for maintenance ranged from 0.1 to 8 micrograms/kg. One patient with idiopathic sporadic neutropenia recovered after 151 days with an absolute neutrophil count (ANC) of > 2000/microliters and had no need for further treatment. The overall efficacy of the treatment was good with abrogation of severe infections. Treatment has been continuously given to a maximum of 4.5 years. No loss of efficacy was observed during long-term treatment. There was no evidence for lineage drain or stem cell exhaustion with prolonged treatment. Cytogenetic analyses in seven of eleven patients did not reveal the development of abnormal cell-clones. G-CSF is safe and efficient in long-term treatment of adult patients with chronic neutropenias.

Adult↗

Growth and differentiation of the human megakaryoblastic cell line (ELF-153): a model for early stages of megakaryocytopoiesis.

ELF-153 is a cell line that has been established from a patient with a poorly differentiated acute myeloid leukemia associated with an acute myelofibrosis. A majority of cells had a blast morphology with the phenotype of a myeloid hematopoietic progenitor, ie, CD34+, CD33+, CD13+, HLA-DR+, but CD38-, and the remaining cells (5% to 10%) expressed platelet restricted proteins such as CD41, CD42, CD36, CD61, and von Willebrand factor; some of them were polyploid (up to 32N) and exhibited demarcation membranes and alpha granules. No erythroid or other lineage-specific markers were detected. Proliferation of ELF-153 cells was highly stimulated by interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor and to a lesser extent by stem cell factor and IL-6. In contrast, the cell line did not respond to erythropoietin, leukemia inhibitory factor, IL-7, IL-11, granulocyte colony-stimulating factor, and basic fibroblast growth factor. ELF-153 cells could be separated by flow cytometry into three discrete cell populations (CD34+/CD61-, CD34+/CD61+, and CD34-/CD61+) with different proliferative and endomitotic properties corresponding to distinct stages of the mega karyocyte (MK) differentiation. This MK differentiation, which involved a minority of ELF-153, could be increased in the presence of 5-azacytidine and phorbol ester, but could not be significantly modified by growth factors. By contrast, cytochalasin B dramatically induced polyploidization without differentiation. It is noteworthy that association of 5-azacytidine to cytochalasin B dramatically induced the production of polyploid MK cells. To understand the molecular mechanisms underlying this MK differentiation, the expression of GATA-1 and GATA-2 was investigated in subpopulations of ELF-153. A high level of GATA-1 and GATA-2 mRNA was only present in the CD61+ cells. Therefore, these two transactivating factors may play an important role in the MK differentiation of ELF-153. We conclude that ELF-153 might be an important tool to investigate the mechanisms by which transcription factors control differentiation of MK progenitors.

Acute Disease↗

Rat platelets contain glycosylated and non-glycosylated forms of platelet factor 4. Identification and characterization by mass spectrometry.

Platelet factor 4 is a heparin-binding protein released from the alpha granules of activated platelets. This study describes the purification and identification of two forms of rat platelet factor 4, the previously characterized non-glycosylated form of 7 kDa and an additional glycosylated form of molecular mass 9 kDa. The two proteins both neutralized the antithrombin-III-dependent inhibitory activity of heparin. Although their amino acid composition was found to be the same, in the N-terminal sequence of the 9-kDa protein, the second threonine residue could not be detected and a difference of 976Da was determined by mass spectrometry. After digestion with O-glycanase and sialidase, the two proteins showed the same molecular mass. Overall consideration of these data led to identification of the higher-molecular-mass protein as a glycosylated form of rat platelet factor 4 with O-glycosylation at the second N-terminal amino acid, while the structure of the oligosaccharide core was established by mass spectrometry and sugar differentiation with lectins. The two forms of platelet factor 4 are both present in platelets and secreted after platelet activation.

Amino Acid Sequence↗

Development of the glycosylphosphatitylinositol-anchoring defect characteristic for paroxysmal nocturnal hemoglobinuria in patients with aplastic anemia.

The introduction of immunosuppressive therapy for treatment of aplastic anemia has led to a considerable improvement in the prognosis of this disease. However, long-term follow-up of these patients showed a high incidence of "late" hematologic complications such as myelodysplasia and paroxysmal nocturnal hemoglobinuria (PNH). The detection of the glycosylphosphatitylinositol (GPI)-anchoring defect on peripheral blood cells of patients with aplastic anemia is now available as a new tool for early specific detection of PNH and is more sensitive than the Ham-test. Granulocytes appear to be the first cells affected in 11 patients with a GPI-anchoring defect of 29 suffering from aplastic anemia investigated in the present study. The later involvement of erythrocytes and a positive Ham test was observed in 1 patient. From our data it can be concluded that the rate of PNH resulting from aplastic anemia might be higher than reported in the literature when the Ham test alone was used for follow-up. Furthermore, our results suggest the clinical response to immunosuppressive therapy appears to be worse in the group developing the GPI-anchoring defect than in the group without this deficiency.

Adolescent↗

Human epidermal Langerhans cells secrete a soluble receptor for IgG (Fc gamma RII/CD32) that inhibits the binding of immune complexes to Fc gamma R+ cells.

Langerhans cells (LC) express Fc gamma RII on their cell surface. In this paper, we demonstrate that these cells also release soluble Fc gamma RII (sFc gamma RII) molecules. LC express transcripts encoding a membrane-associated receptor and a transmembrane-deleted Fc gamma RIIA. The latter form was identified in LC culture supernatants using specific antibodies. CHO cells, transfected with LC-derived cDNA encoding the transmembrane-deleted Fc gamma RIIA, secrete sFc gamma RIIA that include the intracellular domain and exhibit the same backbone as the protein identified in LC supernatants. Secreted sFc gamma RIIA exhibits the same pattern of binding to human and mouse IgG subclasses as do membrane Fc gamma RII and inhibits the binding of immune complexes to Fc gamma RII+ cells. In addition, CHO cells expressing the membrane-associated Fc gamma RIIA release truncated and unstable Fc gamma RIIA molecules that lack the intracellular domain. Thus, sFc gamma RII can result from shedding of membrane molecules and/or from secretion of soluble receptors lacking the transmembrane domain.

Alternative Splicing↗

GM-2 gangliosidosis (Sandhoff's disease): two year follow-up by MRI.

Two children with GM-2 gangliosidosis type 0 (Sandhoff's disease) followed up by MRI at 1.5 Tesla for 1.8 years are reported. One was presymptomatic at the first MRI examination. As her neurological status deteriorated, MRI showed low signal in bilaterally, on T2-weighted images the white matter with involvement of the optic radiations. In the second, MRI correlated well with the clinical progression of the disease, showing in the different stages involvement of thalamus and basal ganglia. There was no contrast enhancement and the grey matter remained normal.

Brain↗

Altered surface marker expression and function of G-CSF-induced neutrophils from test subjects and patients under chemotherapy.

We have previously reported an altered surface marker expression and chemotaxis of G-CSF-induced neutrophils from patients with severe congenital neutropenia. However, effects of G-CSF and influence of the underlying disease on neutrophils could not be discerned. In this study we have evaluated the effects of G-CSF on neutrophil phenotype and function in patients under chemotherapy and in healthy test subjects. We found a significantly enhanced expression of Fc gamma RI, CD14 and CD54 and a decrease in the level of Fc gamma RIII during G-CSF treatment. In addition, motility of G-CSF-induced neutrophils was significantly decreased. The effects were seen in patients under cytotoxic chemotherapy and in healthy test subjects. Surface marker alterations and neutrophil motility were affected by G-CSF administration in a dose-dependent manner. Kinetic studies on neutrophils from healthy test subjects demonstrated that all effects could be seen after a single administration of 300 micrograms G-CSF and began to appear within 4 h. Release of partially immature neutrophils from the bone marrow and indirect activation of these cells by G-CSF are discussed as possible reasons for the findings presented. They demonstrate that G-CSF has profound effects on neutrophil phenotype and function in vivo which might have clinical implications.

Antigens, Surface↗

Correlation of cytogenetic findings with clinical features in 18 patients with inv(3)(q21q26) or t(3;3)(q21;q26).

An inversion in the long arm of chromosome 3--inv(3)(q21q26)--or a translocation between both homologous chromosomes 3--t(3;3)(q21;q26)--is found specifically in myeloid neoplasias characterized by disturbances of thrombopoiesis and megakaryocyte development. Cytogenetic findings were correlated with clinical and hematological data in altogether 18 patients with acute nonlymphocytic leukemia (ANLL) and with inv(3) (13 patients) or t(3;3) (five patients), six of whom were male and 12 who were female. Chromosomal changes in addition to the 3q anomalies were demonstrated in 14 out of 18 patients, predominantly numerical and structural aberrations of chromosome 7 (12 cases) and/or abnormalities of 5q (five cases). Complex karyotype abnormalities were observed in six of 13 patients with inv(3), but in only one of five patients with t(3;3). In ten out of our 18 patients a preceding myelodysplastic syndrome (MDS) and/or exposure to mutagenic/carcinogenic agents had been established. In eight patients the morphology of ANLL blasts was immature (FAB subtype M1); in three patients ANLL-M4, and in two patients each ANLL-M5, M6, and M7 was diagnosed; in one patient with antecedent MDS the leukemic blasts were not classifiable according to the FAB criteria. A disturbed megakaryocyte development, characterized by an excess of micromegakaryocytes was observed in 14 patients, seven of them showed normal or elevated platelet counts as an unusual feature in patients with ANLL. The clinical course and outcome was extremely poor: 15 of 18 patients died within 10 months after the diagnosis of ANLL. Because of their missing response to conventional chemotherapy, patients with inv(3) or t(3;3) have to be estimated as at high risk. The characterization of genes affected by inv(3) or t(3;3) could help to elucidate molecular changes leading to impaired proliferation and differentiation of hematopoietic cells, also of the megakaryocytic lineage. Based on molecular genetic findings new therapeutical approaches could be designed.

Adult↗

Detection and quantification of secreted soluble Fc gamma RIIA in human sera by an enzyme-linked immunosorbent assay.

Fc gamma RIIA can be produced in a soluble form that contains both the extracellular and intracellular regions of the receptor, due to an alternative splicing of the transmembrane domain-coding exon. We have developed an enzyme-linked immunosorbent assay (ELISA) that permits the specific detection and quantification in human sera of this secreted soluble Fc gamma RIIA. It uses the monoclonal antibody (MAb) IV.3 as capture antibody and rabbit polyclonal IgG directed against the intracellular region of Fc gamma RIIA as detector antibodies. The enzymatic reaction was amplified using an NADH/NAD+ amplification system. As little as 0.8-1.5 ng/ml (20-38 pM) of purified recombinant secreted Fc gamma RIIA could be detected. The serum levels of secreted sFc gamma RIIA ranged from 0 to 30 ng/ml in sera from 51 healthy donors. The mean value was 11.9 ng/ml +/- 6.55 (297 pM +/- 163) and the median value was 10.6 ng/ml (265 pM) (range: 0-764 pM).

Animals↗