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Biomedical subjects

E Neumann

Publications and source records attributed to E Neumann.

At least 91 records · Page 5Linked to original sources
PubMed1987

Changes in the oscillatory potentials of the electroretinogram in glaucoma.

Dark adapted and progressively light adapted electroretinograms (ERGs) were recorded from 34 normals and from 45 glaucoma patients. To enhance the oscillatory potentials (OP) the ERGs were highpass-filtered. The OP were characterized by two indices: their root-mean-square value and the inter-flash interval for which the maximal amplitude was obtained. In most of the glaucomatous OP, 50 of 81 eyes, both indices were abnormal, in 22 one parameter was abnormal and only in 9 were both parameters normal. In 13 of the 14 OP recorded from the opposite ('normal') eye of patients with unilateral glaucoma either one or both of the indices were abnormal. These findings indicate that the damage to the retina in glaucoma may extend more distally than the ganglion cell layer and that subclinical changes might be revealed by OP changes.

Adaptation, Physiological↗
PubMed1987

[New aspects in the diagnosis of ischemic heart disease in females].

To investigate still uncertain aspects of the diagnosis of ischemic heart disease (IHD) in women, between 1969 and 1984, repeated exercise studies were performed in 706 asymptomatic women (between the ages of 17 and 63 years). On observation of pathologic ST-segment depression of more than 0.1 mV, the exercise study was repeated after administration of 0.8 mg nitroglycerin. Pathologic ST-segment depression was seen in 310 women (44%). In 217 patients (31%), nitroglycerin had no effect (NTG negative); in 93 women (13%), there was normalization of the ST-segment changes (NTG positive). Additionally, in selected subgroups of patients, pulmonary artery pressure was measured at rest and during exercise and ECG mapping performed (n = 114); radionuclide ventriculograms (n = 64) and 201-thallium scintigrams (n = 99) were obtained and coronary angiography (n = 85) was performed. In the NTG-negative women, ejection fraction, myocardial perfusion and coronary arteries were normal. NTG-positive women had lower mean ejection fractions but still within normal limits and indications of impaired myocardial perfusion. High-grade coronary stenoses were found in 25%. No patient with pathologic ST-segment depression had mitral valve prolapse. NTG-positive women had significantly more risk factors than NTG-negative women. In the former group, pulmonary artery pressure measurements showed pathologic exercise hemodynamics, only in 25% of whom IHD with significant stenosis was found to be the cause. For this condition, differential diagnostic considerations include cardiomyopathy or small vessel disease.

Adolescent↗
PubMed1986

Indium 111-labeled platelet kinetic studies and platelet-associated IgG in hairy cell leukemia.

In order to study the pathogenesis of thrombocytopenia in patients with hairy cell leukemia (HCL), levels of platelet-associated IgG (PAIgG), platelet life span (MLS), and the sequestration site of autologous 111In-labeled platelets were measured in nine patients with HCL. Splenectomized patients (n = 4) had a higher platelet count (x = 122.5 X 10(9)/l; range, 80-190 X 10(9)/l) as well as higher levels of PAIgG (x = 10.7%; range, 5.8-16.9%), than nonsplenectomized patients (platelets x = 76 X 10(9)/l, range 40-100 X 10(9)/l; PAIgG x = 3.2%, range 2.2-4.2%). A normal recovery of 111In-labeled platelets was found in splenectomized patients, whereas a very low recovery was observed in the nonsplenectomized group (x = 70.2%, range, 50-82.5%, versus x = 22.4%, range, 15-28.2%). The MLS was borderline normal in all patients. The site of sequestration was the spleen in nonsplenectomized patients. The low recovery of 111In-labeled platelets in nonsplenectomized patients suggests "hypersplenism" with pooling as a major cause of thrombocytopenia, in addition to impaired thrombocytopoiesis and possible immune-mediated platelet destruction.

Adult↗
PubMed1986

Myeloid progenitor cells in the peripheral blood of patients with hairy cell leukemia and other "leukemic" lymphoproliferative disorders.

We assayed granulocyte-macrophage committed progenitor cells (CFU-GM), erythroid committed progenitor cells (BFU-E) and pluripotent hemopoietic progenitor cells (CFU-MIX) in the peripheral blood of patients with hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL). In 8 HCL patients retaining their spleens, the number of circulating CFU-GM, BFU-E and CFU-MIX were under the lower limits of normal controls in 6, 6 and 5 cases, respectively, and were in the lower normal ranges in the remaining cases. Six splenectomized HCL patients had generally more circulating progenitor cells than their nonsplenectomized counterparts. In the peripheral blood of 2 patients with ALL and 3 patients with CLL, progenitor cells of all types were markedly increased compared to their respective values in the blood of control subjects. Hairy cells from 2 HCL patients failed to inhibit CFU-GM, BFU-E and CFU-MIX derived colony growth from control peripheral blood mononuclear cells. In 3 HCL patients previously low circulating progenitor cells did not rise 5-7 months after RC-alpha 2-IFN treatment despite normalization of peripheral blood counts. Our results suggest that a reduction of the committed and pluripotent progenitor cell compartment might be at least in part responsible for the pancytopenia in the majority of patients with HCL.

Adult↗
PubMed1986

Treatment of severe aplastic anemia with combined immunosuppression (antithymocyte globulin and high-dose methylprednisolone).

Fifteen patients with transfusion-dependent severe aplastic anemia (SAA) were treated with combined immunosuppression consisting of horse-antithymocyte globulin (ATG; Atgam, Upjohn) and high-dose 6-methylprednisolone (MP). Oxymetholone was scheduled for 2 years but was discontinued in 7 patients after 10-385 days due to liver toxicity. Serious side effects usually seen in ATG monotherapy were rare during combined immunosuppression. Currently 12 of 15 patients are alive 110-1,275 days (median 475.5) after start of treatment. One patient has received too short treatment to be evaluated. All the others are transfusion-independent. Three patients died; two from septicemia before hemopoietic recovery could be expected and one after relapse. Our results confirm that the addition of high-dose MP abrogates the side effects of ATG monotherapy, and the addition of MP does not counteract, but rather enhances the beneficial effect of ATG in SAA. We recommend combined immunosuppressive treatment with ATG and high-dose MP as a highly feasible, safe and effectful therapy for patients with transfusion-dependent SAA.

Anemia, Aplastic↗
PubMed1985

Cytogenetic findings in a case of Sézary syndrome.

Repeated cytogenetic studies were carried out on a Sézary syndrome patient during a 1-year period. The presence of a single clone of heteroploid (60-86 chromosomes) cells was a permanent finding in the PHA-stimulated blood cultures. The bone marrow was normal. Sister chromatid exchange (SCE) value was relatively lower in heteroploid cells.

Aged↗
PubMed1985

CHOP-firstline treatment in NHL with unfavorable prognosis--evaluation of therapeutic response and factors influencing prognosis.

58 NHL-patients (9 large cell centrocytic, 18 centroblastic, 16 immunoblastic, 15 lymphoblastic lymphomas) were treated immediately after diagnosis with CHOP-chemotherapy regardless of the extent of disease. Because of the advanced age of the majority of patients (median age 61 years, range 22-85 years) a reduced dose in the first two cycles was administered. Statistically significant prognostic variables influencing survival were the following: histologic subtypes according to the Kiel-classification (p less than 0,05), B-symptoms (p less than 0,001), blood sedimentation rate (p less than 0,02) and LDH (p less than 0,0005). With regard to prognosis there was no difference between patients over 60 years of age and younger ones (p less than 0,4). Patients achieving complete remission survived significantly longer (p less than 0,0001). Ann Arbor stages were of limited value, since patients with CS II disease and accumulation of risk factors (B-symptoms, abdominal disease, bulky tumor masses) showed a poorer outcome than patients with CS III who did not have these risk factors. A risk factor score summarizing features influencing prognosis is described and might be a useful tool in stratifying the heterogeneous group of NHL with unfavorable prognosis.

Adult↗
PubMed1985

Cell lineage heterogeneity in blast crisis of chronic myeloid leukaemia.

Blast cells from 45 patients with chronic myeloid leukaemia in blast crisis (CML-BC) were immunologically phenotyped with a panel of 26 monoclonal antibodies and studied for terminal deoxynucleotidyl transferase (TdT) content. Out of 45 blast-populations, 28 showed a myeloid, 14 a lymphoid, two a mixed and one an unclassifiable marker profile. In contrast to acute myeloid leukaemia (AML), we found frequent involvement of the thrombopoietic and erythropoietic systems in myeloid CML-BC. Furthermore, the marker profile on blast cells in myeloid CML-BC was different from that seen in AML. The blast cells in lymphoid blast crises of CML displayed the same lymphoid marker profile as those in acute lymphoblastic leukaemia. In three of 16 patients who were serially tested, we observed phenotypic changes in the blast cell populations. In one patient the blasts changed from lymphoid to myeloid type while remaining TdT-positive; in another case the blasts switched from granulomonocytic TdT-negative to granulomonocytic TdT-positive. In the third patient erythroid precursor cells appeared as the disease progressed. The results indicate the capacity of blast populations in CML-patients during blast crisis to differentiate along several pathways.

Adolescent↗
PubMed1985

Deficiency of fibrinogen and factor VII following treatment of severe aplastic anaemia with anti-thymocyte globulin and high-dose methylprednisolone.

In 4 patients with SAA treated with ATG and high-dose MP, an as yet unrecognized acquired deficiency of fibrinogen and factor VII was observed. The plasma level of fibrinogen fell to 39% (34-51%) and of factor VII:C to 50% (31-55%) of the pretreatment value. The nadirs were between days 10 and 35 (fibrinogen) and d 3 and 11 (factor VII) after the 1st dose of ATG/MP. From additional clotting studies it is concluded that disseminated intravascular coagulation, fibrinolysis, liver cell damage and synthesis of abnormal clotting factors are unlikely causes of these clotting abnormalities. The most probable explanation seems to be a selective inhibition of the synthesis of fibrinogen and factor VII by an as yet unknown mechanism. These clotting abnormalities might, to some extent, increase the bleeding tendency in these patients, which up to now had been solely attributed to thrombocytopenia.

Adult↗
PubMed1985

Treatment of severe chronic idiopathic thrombocytopenic purpura in adults with high-dose intravenous gammaglobulin.

12 patients with severe chronic idiopathic thrombocytopenic purpura (ITP) were treated with i.v. polyvalent intact immunoglobulin (0.14-0.4 g/kg body weight for 5 d) because of various bleeding episodes or prior to surgery. In 9 patients a significant rise in platelet counts was noted, starting on d 2 and reaching its maximum between d 4 and 11. Thereafter, platelet counts decreased slowly, approaching pre-treatment values after 20 d in most cases. Response to immunoglobulin was reproducible, when infusions were repeated. Response to high-dose immunoglobulin was independent of age of patients and duration of disease. Platelet-associated IgG decreased in all patients tested. A pepsin-treated immunoglobulin preparation was ineffective in 3 patients.

Adult↗
PubMed1984

Long-lived metastable states and hysteresis in the binding of acetylcholine to Torpedo california acetylcholine receptor.

Studies of the binding of [3H]acetylcholine to receptor-rich membranes of Torpedo californica electric organ under conditions that normally lead to a state of equilibrium did not give rise to equilibrium binding curves. Instead, the acetylcholine receptor was found to develop very long lived metastable states resulting in hysteresis in binding. Under conditions where the concentration of free [3H]acetylcholine is both less than 0.1 microM and smaller or comparable to the total receptor concentration, the degree of binding of acetylcholine depends on the rate, i.e., the mode, of increasing the acetylcholine concentration (rapid mixing vs. dialysis). The equilibrium positive cooperativity in high-affinity acetylcholine binding previously inferred from the data is deceiving; the curvature in Scatchard representations is a consequence of long-lived nonequilibrium distributions between high-affinity and lower affinity receptor conformers. By manipulation of the experimental conditions, true equilibrium binding, resulting in a linear Scatchard binding curve, was obtained and yielded the apparent equilibrium constant, K = 5 +/- 1 nM at 4 degrees C. The stoichiometry of the high-affinity site associated with this K value was found to be one acetylcholine per receptor monomer (Mr 250 000) when carefully standardized [3H]acetylcholine analyzed for both radiopurity and acetylcholine concentration was used. While our fresh membrane fragments prepared in the presence of 4 mM Ca2+ revealed up to twice as many 125I-alpha-bungarotoxin sites in 0.1% nonionic detergent relative to those assayed in the absence of detergent, nonionic detergent treatment of membrane fragments did not result in any change in total available acetylcholine binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1984

Malignant histiocytosis with unusual features. Disseminated intravascular coagulation with severe hyperfibrinolysis, acute polyneuroradiculitis Guillain-Barré, and a unique chromosome abnormality.

The case of a 25-year-old man with the characteristic features of malignant histiocytosis (proliferation of abnormal histiocytic cells with erythrophagocytosis, hepatosplenomegaly, increased serum acid phosphatase, hypercalcemia, and bone pain) is reported. Chromosome studies revealed a near tetraploid karyotype with a pair of marker chromosomes. A few hours after initiation of chemotherapy with cyclophosphamide, Adriamycin (doxorubicin), vincristine, and prednisolone (CHOP regimen), the patient developed an acute ascending paralysis. Cerebrospinal fluid (CSF) findings were consistent with a diagnosis of Guillain-Barré Syndrome. On the next day, disseminated intravascular coagulation (DIC) with severe hyperfibrinolysis occurred. After intensive chemotherapy, complete remission could be achieved.

Adult↗
PubMed1984

Efficacy of the M-2 protocol in previously untreated patients with advanced multiple myeloma.

37 consecutive, previously untreated patients with advanced multiple myeloma (16 patients Stage II, 21 patients Stage III) were treated with a five drug regimen consisting of carmustine, melphalan, vincristine, cyclophosphamide and prednisolone (M-2-protocol) in a prospective manner. Remission was achieved in 24 patients (65%). The median time to remission was 10 weeks, the median duration of remission 15,3 months. Median survival time from the onset of treatment was 24 months for all patients. Responding patients have a projected 65% three year survival. Median survival in non-responders was 10 months. 8 patients died during the first year of treatment. These results do not confirm the favourable results with this drug combination obtained in a previous trial. The discrepancy may be explained by a higher proportion of poor risk patients in the present study.

Aged↗
PubMed1984

Stochastic model for electric field-induced membrane pores. Electroporation.

Electric impulses (1-20 kV cm-1, 1-5 microseconds) cause transient structural changes in biological membranes and lipid bilayers, leading to apparently reversible pore formation ( electroporation ) with cross-membrane material flow and, if two membranes are in contact, to irreversible membrane fusion ( electrofusion ). The fundamental process operative in electroporation and electrofusion is treated in terms of a periodic lipid block model, a block being a nearest-neighbour pair of lipid molecules in either of two states: (i) the polar head group in the bilayer plane or (ii) facing the centre of a pore (or defect site). The number of blocks in the pore wall is the stochastic variable of the model describing pore size and stability. The Helmholtz free energy function characterizing the transition probabilities of the various pore states contains the surface energies of the pore wall and the planar bilayer and, if an electric field is present, also a dielectric polarization term (dominated by the polarization of the water layer adjacent to the pore wall). Assuming a Poisson process the average number of blocks in a pore wall is given by the solution of a non-linear differential equation. At subcritical electric fields the average pore size is stationary and very small. At supercritical field strengths the pore radius increases and, reaching a critical pore size, the membrane ruptures (dielectric breakdown). If, however, the electric field is switched off, before the critical pore radius is reached, the pore apparently completely reseals to the closed bilayer configuration (reversible electroporation ).

Electric Conductivity↗
PubMed1984

Different channel properties of Torpedo acetylcholine receptor monomers and dimers reconstituted in planar membranes.

It is demonstrated that the monomeric and dimeric structures of the nicotinic acetylcholine receptor of Torpedo californica electric tissue, reconstituted in planar lipid bilayers, are functionally different. The native dimer D of Mr 500,000 (heavy-form) exhibits a "single" channel conductance about twice as large as that of the monomer M of Mr 250,000 (light form). Under conditions where monomers aggregate, the conductance changes from the level of the monomer M to that of dimers M2. The dimer conductances (D and M2) seem to result from synchronous opening and closing of the two channels in the dimer, giving the impression of "single channel" activity. This channel cooperativity is apparently mediated by noncovalent interactions between the two monomers, since it requires no disulfide linkage between monomers. Both the monomers M and the dimers D and M2 show at least one substate of lower conductivity. The relative population of the two conductance levels depends on the ion type (Na+ and K+), indicating ion-specific channel states. Since the channel conductance of isolated dimers resembles those obtained from unextracted microsacs, the dimer with two synchronized channels appears to be the in vivo predominant gating unit. In the linear association of dimers, observed in the native membrane, channel synchronization may extend to more than two channels as suggested by oligomeric channel cooperativity in associations of monomers and dimers.

Animals↗