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Biomedical subjects

E Neumann

Publications and source records attributed to E Neumann.

At least 73 records · Page 4Linked to original sources
PubMed1991

Behavior problems and adaptive functioning in children with mild and severe closed head injury.

Assessed behavior problems and adaptive functioning in children with mild or severe closed head injuries, on average more than 2 years postaccident. To ensure that any problems detected in the present study were not merely preexisting problems, potential subjects were excluded if there was a history of preexisting CNS damage, significant developmental delay, or behavior problems. Children with severe head injuries had an excessive rate of behavior problems and impaired adaptive functioning. Children with mild head injuries also had an excessive rate of behavior problems (comparable to that of children with severe head injuries) but did not have impaired adaptive functioning. Results are discussed in terms of six alternative ways brain injury and behavior problems can be related functionally.

Activities of Daily Living↗
PubMed1991

Recurrent corneal oedema following late migration of intraocular glass.

This is a report of very late complications following intraocular penetration of numerous fragments of glass as a result of a test tube explosion. Fifteen years after the initial injury glass splinters began to migrate from the vitreous into the anterior chamber, causing acute episodes of corneal oedema. Four such episodes occurred over the past nine years, the corneal oedema each time disappearing within a few days following surgical extraction of the glass splinters. The literature on intraocular glass and its movement within the eye is reviewed.

Adolescent↗
PubMed1990

The nematocyst extract of Hydra attenuata causes single channel events in lipid bilayers.

The nematocyst extract of Hydra attenuata causes single conductance events in reconstituted planar lipid membranes as well as in inside-out patches derived from liposomes. The smallest single channel conductance level of the toxins is 110 pS. The conductance levels increase stepwise with time up to 2000 pS. These large conductance jumps indicate channel cooperativity. If the membrane-voltage is changed from positive to negative values, the single channel events become undefined and noisy, indicating major reorganizations of the proteins which form the channels. The molecular properties of the ionophoric component(s) of the nematocyst extract may help explain the observed macroscopic effects, such as hemolysis of human erythrocytes, after addition of the nematocyst extract.

Animals↗
PubMed1990

[Semi-invasive measurement of pulmonary pressure as a method of evaluating cardiac function in hypertension and ischemic heart disease. Experience at Charité Hospital for more than 20 years].

Since 1969, microcatheterization (floating catheterization) of the pulmonary artery has systematically been used at the Hospital Charité in Berlin for measuring (indirectly) the left ventricular filling pressure. That seemed especially be justified in patients in whom conventional catheterization was not needed. Noninvasive techniques had not been available. Since then, our interest was focused on the hypertensive heart, earlier under the aspect of early discovering and influencing heart insufficiency, later concerning a developing myocardial ischemia, in relationship to left ventricular hypertrophy. At the Charité more than 1,000 microcatheterizations in more than 400 hypertensive cases have been performed, mostly in combination with nuclear-cardiological measurements. The rate of complications was found minimal. Thus, cardiac function could be characterized hemodynamically, at rest and even under ergometric load. Special programmes served the acute application of drugs for diagnostic or therapeutic reasons. In the meantime a longterm study could also be finished by using hemodynamic measurements, starting with hygienic means and followed by a antihypertensive basis therapy, in newly detected hypertensives. That included repeated catheterizations of the pulmonary artery.

Catheterization, Peripheral↗
PubMed1989

Miscibility of octyl glucoside-phosphatidylcholine micellar solutions. Partition of the nicotinic acetylcholine receptor into the surfactant-rich phase.

Phospholipid phosphatidylcholines (PC) and the nonionic detergent octyl glucoside (OG) were found to form a miscibility gap in aqueous solution at a molar ratio [OC]T/[PC]T=2.6-2.4. This ratio is just below the critical ratio for the formation of vesicles. At [PC] greater than 1.3 g/l the transition from micelles to vesicles is not direct but via a surfactant-rich phase (SRP). The various stability regions are summarized in a phase diagram. Though the partition coefficient gamma=[Db]/[Dw] increases markedly with temperature, the critical ratio for the phase separation R(c) is biased to higher detergent concentrations. This behaviour can be explained by increased motion of the hydrocarbon moiety at higher temperatures. The different phases are investigated by light microscopy, nuclear magnetic resonance and thin-layer chromatography. The miscibility gap of PC/OG is compared to the lamellar phase of Triton X-114; the miscibility gap has implications for membrane protein reconstitution and can be used for membrane protein purification. The Torpedo californica nicotinic acetylcholine receptor (n-AcChR) was found to partition into the SRP.

Animals↗
PubMed1989

Miniature fiber-optic pattern-reversal stimulator for determination of the visual evoked potential threshold; comparison with Snellen acuity.

In this report we recommend the estimation of visual acuity by detection of the visual evoked potential (VEP) threshold, defined by the smallest visual angle of a constant check size that evokes potentials. This approach was implemented using a fiber-optic pattern-reversal stimulator placed at measured, increasing distances from the examined eye. Snellen visual acuity as determined in 113 subjects was correlated with the VEP detection threshold. A highly significant correlation was found between visual acuity and the threshold visual angle of check size in subjects whose vision was impaired due to opacity in ocular media. For any given visual acuity a somewhat wide range of threshold check sizes, typically 5-10 min of arc was observed. Technical difficulties that need to be overcome to improve these results are discussed.

Adult↗
PubMed1989

Effects of gentamycin and chloramphenicol on the transparency of cultured rat lenses.

The effect of the antibiotics gentamycin and chloramphenicol on lens opacity was studied in an organ culture system. Opacity was monitored by split laser beam. Both antibiotics enhanced the onset of opacity in the cultured lenses under a variety of conditions. For instance, treatment with 5.0 mg/ml gentamycin for 60 min caused initial opacity after 4.8 +/- 1.3 days as opposed to untreated lenses at which initial opacity appeared after 18.1 +/- 2.99 days. Exposure to 20 mg/ml chloramphenicol for 60 min caused initial opacity after 4.6 +/- 1.51 days. Continuous exposure to penicillin and streptomycin (0.1 mg/ml each) did not enhance the onset of opacity.

Age Factors↗
PubMed1989

[Differential therapy of myocardial ischemia in females].

Peripheral perfusion abnormalities are considered a possible reason for myocardial ischemia in the absence of visible coronary artery stenoses. In 85 women (age: 41-58 years, mean age: 46 +/- 8) with pathological exercise ECG (precordial mapping: 50 leads), hemodynamic studies were performed without medication, after sublingual nitroglycerin (NTG, 0.8 mg), sublingual Nifedipin (N, 30 mg), and intravenous Dipyridamol (D, 0.5 mg/kg). Eighteen women showed normal coronary arteries and a normal myocardial perfusion (group I), 21 an impaired perfusion due to coronary stenoses (Group II), and 46 women a reduced perfusion without visible changes (Group III). Reference methods were measurement of pulmonary artery pressure, 201-TI-scintigraphy, and coronary angiography. In group II, enddiastolic and endsystolic left ventricular volume (EDV, ESV) as well as enddiastolic pulmonary artery pressure (pAd) were increased, the ejection fraction (EF) was reduced, and cardiac output (CO) was normal. In group III, ESV, EDV, EF, and CO were significantly reduced, while pAd increased. In group II, N led to a normalization of ESV, EDV, EF, and pAd. In group III, NTG led to a reduction of pAd and EDV, and concomitantly to a further reduction of the already low CO. In both groups the reduction of ST-segment depressions after NTG was significant. N led to a moderate reduction of pAd and ST-segment depression, but to an increase of CO in both groups. D exhibited a comparable effect in group III. In group II an increase of ST-segment changes and of pAd with unchanged CO was observed. With regard to longterm treatment of women in group III, N and D seemed to be more efficacious than nitrates due to a beneficial effect on cardiac output.

Administration, Sublingual↗
PubMed1988

[High dosage and intermediate dosage cytosine arabinoside in the treatment of secondary leukemias].

Patients with secondary acute myeloid leukaemia (AML) following treatment with alkylating agents and/or radiation show a poor response to standard induction therapy. Between 1983-1987 8 consecutive patients were treated with high-dose cytosine arabinoside (HD-ARA C; 3 g/sqm twice daily for 6 days) or intermediate-dose cytosine arabinoside (ID-ARA C; 0.5 g/sqm twice daily for 6 days). Complete remission was achieved in 3 patients (HD-ARA C: 2/3l; ID-ARA C: 1/5) and partial remission in 3 patients (ID-ARA C: 3/5). One patient (HD-ARA C) died during prolonged aplasia, one patient (ID-ARA C) proved refractory to treatment. The respective duration of remission in the 3 responsive patients was 3, 7 and 8 months. The probability of survival of the whole group was 50% after 12 months and 25% after 24 months. Our results confirm the efficacy of monotherapy with ARA C in the treatment of secondary AML. Consolidation therapy with ID-ARA C for 4 days seems to prolong remission.

Adult↗
PubMed1988

Recombinant alpha-interferon (alpha-IFN) for progressive hairy-cell leukemia (HCL): a study in previously untreated nonsplenectomized patients.

Ten nonsplenectomized patients (5 males, 5 females) with hairy-cell leukemia were treated with recombinant alpha-IFN. The median age of patients was 54 years (32-76 years). The time between diagnosis and onset of treatment ranged from 1-120 months. Initially the patients received 5 x 10(6) I.U. daily by intramuscular or subcutaneous injections for 10 weeks. Thereafter the dose of IFN was reduced to 5 x 10(6) I.U. 3 x weekly and after 6 months to 5 x 10(6) I.U. 2 x weekly for at least 6 months. The median time of patient follow-up is 23 months (4-28 months). Three complete remissions were achieved after 3-24 months and five partial remissions after 4-18 months. One patient showed improvement after 3 months, and one patient died from cerebral hemorrhage after 5 weeks. In eight of ten patients peripheral blood cell counts normalized after a median of 7 months (1.5-11 months). A marked reduction in spleen size was observed in all seven patients who had splenomegaly at study entry. Two of three patients who interrupted therapy have relapsed after 2 and 6 months. We conclude that alpha-interferon is an effective method of first-line treatment in patients with HCL.

Adult↗
PubMed1988

Deficiency of pluripotent hemopoietic progenitor cells in myelodysplastic syndromes.

Pluripotent (CFU-MIX), erythroid (BFU-E) and granulocyte/macrophage (CFU-GM) progenitor cells were examined in bone marrow (BM) from 23 patients with myelodysplastic syndromes (MDS). Patients were grouped according to the FAB classification: Refractory anemia (RA), n = 3; RA with ring sideroblasts (RARS), n = 3; RA with excess of blasts (RAEB), n = 8; RA with excess of blasts in transformation (RAEBt), n = 7; chronic myelomonocytic leukemia (CMML), n = 2. In FAB groups RA, RARS, RAEB and RAEBt CFU-GM concentrations were normal or decreased but both CMML-patients had increased CFU-GM values. Abnormal cluster growth was observed in 9 of 23 MDS-patients. BFU-E colony formation was subnormal in all cases. Mixed-colony assay values were at the lower limit of controls in one patient and decreased in the remaining 22 MDS-patients. A similar growth pattern of hemopoietic progenitor cells was observed in 19 patients with acute nonlymphocytic leukemia (ANLL), who were studied for comparison. These data suggest a quantitative or qualitative/functional defect of the pluripotent progenitor cell compartment as the major cause for the cytopenia in MDS-patients.

Aged↗
PubMed1988

Diagnosis of silent myocardial ischemia in women.

The diagnosis of silent ischaemic heart disease may be important in men as well as in women. However, diagnosing women by exercise ECG is limited due to the higher rate of false positive results. For improving diagnostic validity the following investigations were done. In 310 women, aged 41-63 years (mean age 47 years', revealing 'pathological' exercise ECG, further testing was performed using nitroglycerin (NTG 0.8 mg). As a reference method, pulmonary artery (PA) pressure measurement was used. As a result of NTG testing, two groups could be separated: (a) those in whom ST segment depression remained constant (N = 217, NTG negatives = 70%). Since the end-diastolic PA pressure was found normal, these results were interpreted to be false-positive. (b) NTG effected a reduction or normalization of exercise induced ST segment changes (N = 93, NTG positives = 30%). There was a correspondence with exercise inducible end-diastolic PA pressure decrease. Consequently, true positives were assumed. Analysis of angina pectoris history indicated typical chest pain in 2% of NTG negatives only, but in 16% of NTG positives. In agreement with this during exercise, angina was reported by NTG negatives in 3% of cases and by NTG positive in 17%. The rest of this group (83%) is considered having exercise induceable silent myocardial ischaemia. When checking-up after five years, exercised-induced angina could be found in 4% of NTG negatives again, but in 36% of NTG positives. It was concluded that exercise testing by additionally using nitroglycerin is a rather important approach for diagnosing myocardial ischaemia in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Phosphorylation of phosphatidylinositol associated with the nicotinic acetylcholine receptor of Torpedo californica.

When isolated, detergent solubilized and affinity chromatographically purified nicotinic acetylcholine receptor of Torpedo californica electric organ is incubated with [gamma-32P]ATP/Mg2+, phosphatidylinositol 4-phosphate (PIP) is formed from receptor associated phosphatidylinositol (PI). This receptor associated endogenous kinase activity is enhanced by orthovanadate and, remarkably, also by acetylcholine. Exogenously added PI-kinase only increases the phosphorylation rate if vanadate is present. PIP as the main phosphorylation product (up to 95%) remains bound to the beta-, gamma- and delta-subunits of the receptor and to the receptor associated v-protein. The alpha-subunits do not carry 32p phosphate; no phosphatidylinositol 4,5-bisphosphate formation has been observed. Concomitant to lipid phosphorylation tyrosine and serine residues are phosphorylated (5% of total incorporated 32P phosphate).

1-Phosphatidylinositol 4-Kinase↗
PubMed1987

Model of cell electrofusion. Membrane electroporation, pore coalescence and percolation.

High electric field impulses (1-20 kV/cm, 1-20 microseconds) may trigger fusion between adhering cells or lipid vesicles (electrofusion). In this paper a qualitative model of electrofusion is proposed consistent with both electron and light microscopic data. Electrofusion is considered as a multistep process comprising tight membrane-contact formation, membrane electroporation as well as an alternating series of subsequent fast collective and slow diffusive fusion stages. The following sequence of steps is suggested: The electric field pulse enforces (via polarization) a tight contact between the membranes of the cells or vesicles to be fused. During tight-contact formation between the opposing membrane surfaces the membrane-adherent water layers are partially squeezed out from the intermembraneous space. Pores are formed in the double membrane contact area (electroporation) involving lateral diffusion and rotation of the lipid molecules in both adhering membrane parts. With increasing pore density, pore-pore interactions lead to short-range coalescence of double membrane pores resulting in ramified cracks; especially small tongues and loops are formed. At supercritical pore density long-range coalescence of the pores occurs (percolation) producing one large double membrane loop (or tongue) and subsequently one large hole in the contact area. After switching off the electric field, the smaller pores, tongues and loops reseal and water flows back into the intermembraneous space of the double membrane in the contact area. As a consequence of the increasing membrane-membrane separation due to water backflow, cooperative rounding of the edges of remaining larger tongues and holes occurs. This results in the formation of an intercellular cytoplasm bridge (channel) concomitant with the disappearance of the contact line between the fusing cells. The membrane parts surrounded by continuous loop-like cracks may separate from the system and may finally form vesicles. Our electrofusion model comprises a strong linkage between the membrane pore formation by high electric fields (electroporation) and the process of electrofusion. Additionally, both pore-pore interactions as well as protein-protein interactions in the contact area of the fusing cells are explicitly introduced. The model provides a qualitative molecular description of basic experimental observations such as the production of membrane fragments, of smaller inside-out vesicles and the formation of larger intercellular cytoplasm bridges.

Cell Membrane Permeability↗
PubMed1987

[Allogeneic bone marrow transplantation in acute myeloid leukemia (AML): results in 14 patients].

Between February 1982 and August 1986 14 patients with AML (median age 24 years, range 10-41) underwent allogeneic bone marrow transplantation. 9 patients were grafted in first complete remission, 4 in first relapse, 1 in second relapse and 1 patient with refractory AML. Conditioning consisted of cyclophosphamide (120 mg/kg) and total body irradiation (1000 rad). The patients received methotrexate (n = 12) or methotrexate and cyclosporine (n = 2) for prevention of graft versus host disease. Of the 14 patients, 7 are alive, 7 patients died. Causes of death were recurrence of leukaemia (n = 2), veno occlusive disease of the liver (n = 1), CMV-pneumonitis (n = 1), septicaemia (1), cerebral haemorrhage (1), acute graft versus host disease of the gut (1), necrotizing encephalopathy (n = 1). 7 patients are alive between 124 and 1784 days (median 671) in continuous complete remission. All patients but 1 have a Karnofsky-index of more than 80%.

Adolescent↗
PubMed1987

In vitro culture studies of granulocyte/macrophage and erythroid progenitor cells in lymphoproliferative disorders.

Granulocyte/macrophage progenitor cells (CFU-GM) and erythroid progenitor cells (BFU-E) have been assayed in peripheral blood (PB) and/or bone marrow (BM) from 12 patients with acute lymphocytic leukemia (ALL), 16 patients with chronic lymphocytic leukemia (CLL) and 31 patients with various forms of non-Hodgkin lymphoma (NHL) without BM involvement. Progenitor cell growth in PB and BM from the NHL patients did not differ statistically from controls (p greater than 0.1). CFU-GM and BFU-E per ml PB were markedly increased in ALL and CLL patients (p less than 0.001) while CFU-GM and BFU-E per plated BM cells from these patients were severely depressed (p less than 0.001). Lymphoblasts from one ALL patient failed to inhibit CFU-GM and BFU-E-derived colony growth from control PB mononuclear cells. The high levels of circulating progenitor cells in ALL and CLL patients clearly distinguish them from other cytopenic hematological malignancies, in which decreased progenitor cell levels have been demonstrated previously (acute myeloid leukemia, hairy cell leukemia). The cause of this finding and its pathophysiological implication still remains to be established.

Bone Marrow↗