Search PubMed⌕ Search

Biomedical subjects

M Jahn

Publications and source records attributed to M Jahn.

70 records · Page 4Linked to original sources
PubMed1990

Physical and immunological characterization of human transcription factor IIIA.

Human transcription factor IIIA (htFIIIA), specifically required for transcription of the gene for 5S ribosomal RNA has been characterized with respect to some of its physical, immunological and functional properties. TFIIIA from HeLa cells, which selectively binds 5S RNA, is a monomer of approximately 35 kDa with a Stokes' radius of approximately 2.65 nm and a sedimentation coefficient of approximately 2.8 S. These values indicate that the human protein is of rather globular shape and hence diverges not only in molecular mass but also in most of the molecular properties from its highly asymmetric counterpart in Xenopus laevis oocytes. By raising specific polyclonal antibodies against hTFIIIA it was shown in Western immunoblots that there was no cross-reaction between anti-hTFIIIA antibodies and the amphibian protein. Conversely, monoclonal antibodies against three domains of X. laevis TFIIIA antibodies and the amphibian protein. Conversely, monoclonal antibodies against three domains of X. laevis TFIIIA did not cross-react with the human transcription factor. The polyclonal antisera raised against hTFIIIA specifically neutralized binding of the human transcription factor to 5S DNA and abolished in vitro transcription of 5S RNA but these antibodies were unable to inhibit 5S RNA synthesis in cellular extracts from Xenopus, Drosophila or yeast cells. Finally, the species variation of TFIIIA could be substantiated by electrophoretic mobility shift assays revealing preferential binding of hTFIIIA to the homologous 5S RNA gene.

Animals↗
PubMed1990

[Diuretic-induced edema].

The diagnosis of "diuretic-induced oedema" was made in 17 women (mean age 42.4 [23-60] years) who had developed generalized oedema after stopping their (chronic) intake of diuretics. Five patients were between 11 and 32% overweight, five of them were unusually old. A further four patients had severe concomitant diseases, such as primary lymphoedema, mitral valve defect and lupus erythematosus. In 10 of the 17 discontinuation was successful: the initial weight gain averaged 3.9 (1.5-7.5) kg. The maximal weight-gain, in a woman in the course of weaning her of the diuretic, was reversed within 20 days. Diuretic withdrawal after more than 20 years in a woman with mitral valve disease caused heart failure. Diuretic abuse caused prerenal failure in one women, but renal function became normal again after stopping of the diuretic and rehydration.

Adult↗
PubMed1990

[Why are there anti-cardiolipin antibodies in patients with infectious mononucleosis and in patients with systemic lupus erythematosus?].

The phenomenon of anticardiolipin antibodies (aCL) is in recent years the subject of interest as it is connected with manifestations of thromboses at different sites, with repeated miscarriages in pregnant women and with thrombocytopenia. As compared with the original finding in patients with systemic lupus erythematosus (SLE), the authors find they are present also in infection with the Epstein-Barr virus--in patients with acute infectious mononucleosis, in as many as 61% of a total number of 77 examined patients; in a group of 60 patients with SLE in 41% and in a group of healthy controls in 3.9%. aCL differ, however, as regards the distribution of isotypes--aCL of class IgM are found mainly in infectious mononucleosis, class IgG in patients with SLE. The authors discuss problems associated with the development and practical importance of these antibodies.

Adolescent↗
PubMed1988

Essential thrombocythemia. Clinical characteristics and course of 61 cases.

Sixty-one patients with essential thrombocythemia (ET) were followed from 1974 through 1987 at the Medizinische Poliklinik. Fifty-one patients (84%) presented with thromboembolic complications, and eight patients (13%) with hemorrhages. In seven patients (12%), a thrombocytosis was detected accidentally. Disturbances of the microcirculation (67%), mainly of the fingers and toes (53%), were the most frequent thromboembolic symptoms. The mean age of all patients was 58 years (male patients, 61 years; female patients, 56 years). The average platelet count at diagnosis was 897,000/microliter. The average maximal platelet count was 1.231 X 10(6)/microliter (range, 500,000/microliter to 4 X 10(6)/microliter). Seventy-two percent had a moderate leukocytosis (average, 12,400/microliter), 34% a splenomegaly, 29% a hepatomegaly. Signs of hypermetabolism were infrequent, lactate dehydrogenase (LDH) and uric acid elevations, if present, were moderate. Bleeding time and viscosity were normal in most patients. Spontaneous platelet aggregation was increased in 81% of patients (n = 40). Platelet aggregation studies with the aggregation inducing substances adenosine diphosphonate (ADP), platelet activating factor (PAF), thrombin, collagen, and adrenalin showed hypoaggregation in most patients. Adrenalin-induced aggregation distinguished best between ET-patients and reactive thrombocytosis showing hypoaggregation in all ET-patients tested (n = 16) and in none of 22 controls. Bone marrow studies were performed in 57 patients. The histologic studies (done in 49 patients) were consistent with a chronic myeloproliferative disorder in all cases. In 41 cases (84%) the picture of a megakaryocytic myelosis was found, in 12 of these a granulocyte-rich form of megakaryocytic myelosis. Cytologic studies only (eight patients) did not differentiate ET well from reactive thrombocytosis. Platelet aggregation studies and bone marrow histology may be of help in the diagnosis of difficult cases of thrombocytosis. The Philadelphia status was negative in all cases studied (14 patients). Fourteen patients died. The causes of death were thromboembolic complications in probably 11 and acute leukemia in two patients. The probability of 10-year survival is 64% after a mean follow-up time of approximately 5 years. It appears that considering the average age of ET patients at diagnosis, life expectancy is close to normal.

Bone Marrow↗
PubMed1988

[Clinical characterization of essential thrombocythemia in comparison with other myeloproliferative diseases and reactive thrombocytoses].

60 patients with essential thrombocythemia (ET) have been retrospectively and prospectively followed from 1974 through 1987. The presenting signs and symptoms and the course of the disease were analyzed and compared to 10 patients with persisting reactive thrombocytosis selected from 6,000 patients with reactive thrombocytosis and to 50 patients with other myeloproliferative diseases. 54 ET-patients presented with complications, 46 with thrombembolic, 3 with hemorrhagic problems and 5 with thrombembolic and hemorrhagic problems. In 6 patients ET was detected accidentally. Disturbances of the microcirculation, mainly of the fingers and the toes, were the most frequent symptom. The average maximal platelet count was 1,207,000/microliter. The average platelet count at diagnosis was 880,000/microliter. 16 patients had an elevation of the serum creatinine at diagnosis, which deteriorated during the course of the disease. Bone marrow examinations were performed in 56 patients, histology in 48 patients, cytology in 29 patients. In contrast to the clinical diagnosis the histological diagnosis was in 4 cases each polycythemia vera and myeloproliferative syndrome without further specification. 12 patients died thus far. The causes of death were thrombembolic complications in 9, acute leukemia in 2 patients, in 1 patient the cause of death is not known. 10 years after diagnosis 61% of the patients are still alive. It appears that ET is a more important risk factor for the disturbances of the micro- and macrocirculation than has been recognized until now. ET is, if thrombembolic complications are avoided, a disease with a relatively benign course.

Aged↗
PubMed1978

[Inappropriate secretion of anti-diuretic hormone in a case of intermittent acute porphyria (author's transl)].

The authors report the case of a patient who presented, during two exacerbations of intermittent acute porphyria, a grave psychiatric syndrome secondary to severe hyponatraemia. The later was due to inappropriate secretion of anti-diuretic hormone confirmed by laboratory tests and the stimation of anti-diuretic activity in the urine. The course was favourable under the effects of symptomatic treatment including sodium supplements and fluid restriction. The anti-diuretic syndrome disappeared on each occasion without sequelae at the time of regression of the exacerbation of porphyria.

Acute Disease↗