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Biomedical subjects

H Erdmann

Publications and source records attributed to H Erdmann.

At least 19 recordsLinked to original sources
PubMed2003

Studies on modifying the tackiness and drug release of Kollicoat EMM 30 D coatings.

In the search for antitack additives for Kollicoat EMM 30 D (ethyl acrylate-methyl methacrylate 30% dispersion, Ph. Eur.) film coatings, various possibilities were investigated. The best results were obtained using a combination of simethicone and talc. This mixture was tested on propranolol, theophylline, and verapamil HCl blank pellets in a previously developed Kollicoat EMM 30 D basic formulation. Almost any desired drug release rate can be obtained with all three pellet formulations by varying the two pore formers hypromellose 3mPas and microcrystalline cellulose type 105. A thin application of colloidal silica onto the coated pellets additionally prevents them from sticking together during storage.

Chemistry, Pharmaceutical↗
PubMed2001

Vascular endothelial growth factor (VEGF)--a valuable serum tumour marker in patients with colorectal cancer?

INTRODUCTION: Neo-angiogenesis, of great importance for tumour growth and nutrition, is preferentially mediated by the cytokine vascular endothelial growth factor (VEGF), which has a direct effect on vascular endothelial cell proliferation and migration. This study was designed to clarify whether VEGF is a suitable tumour marker in sera of patients with a colorectal cancer, and whether VEGF concentrations in sera and tumour tissues are correlated with tumour extension (pTNM) and especially with tumour volume or size. Furthermore, the influence of VEGF levels on patients >> prognosis was examined. METHODS: VEGF serum concentrations of 122 patients with colorectal cancer and 65 controls were determined with an ELISA kit. Additionally, VEGF concentrations of tumour and normal tissue were measured in 38 patients using the same ELISA. RESULTS: Our results demonstrate that VEGF is not a suitable diagnostic tumour marker in patients with colorectal cancer due to its low sensitivity (36%). However, a combination of the serum tumour markers CEA and VEGF can significantly increase the pre-operative diagnostic sensitivity to 62%. VEGF serum levels differed significantly between patients (mean 438 pg/ml) and controls (mean 203 pg/ml), and also between tumour and normal tissue (984 vs 89 pg/mg protein). Serum concentration showed a significant correlation to tumour volume and size. Patients with VEGF serum levels greater than cut-off had a poorer prognosis than those less than or equal to cut-off. For this reason VEGF could be used as a predictor of patients >> outcome.

Adult↗
PubMed1998

[Determination of vascular endothelial growth factor (VEGF) concentration in serum of patients with colorectal carcinoma].

The aim of our study was to determine the serum concentration of VEGF in 53 patients with a colorectal carcinoma and 22 healthy volunteers (control group) and to compare it with tumor stage and volume. We found significantly higher serum levels in tumor patients in contrast to the control group and between patients with and without distant metastases. There was also a correlation between high serum concentrations and great tumor volumes, but only weak with tumor stage. Our results support the hypothesis that tumor growth is dependent on angiogenesis and that VEGF is a potent growth factor with angiogenic activity.

Aged↗
PubMed1995

Crystal structure of NADH oxidase from Thermus thermophilus.

The crystal structures of the flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) containing isoforms of NADH oxidase from Thermus thermophilus have been determined by isomorphous and molecular replacement and refined to 2.3 A and 1.6 A resolution with R-values of 18.5% and 18.6% respectively. The structure of the homodimeric enzyme consists of a central 4-stranded antiparallel beta-sheet covered by helices, a more flexible domain formed by two helices, and a C-terminal excursion connecting the subunits. The active sites are located in a deep cleft between the subunits. The binding site of the flavin cofactor lacks the common nucleotide binding fold and is different from the FMN binding site found in flavodoxins.

Binding Sites↗
PubMed1993

Crystallization and preliminary X-ray diffraction studies of a NADH oxidase from Thermus thermophilus HB8.

The thermophile NADH oxidase from Thermus thermophilus, cloned and expressed in Escherichia coli, has been purified to homogeneity and crystallized. Three different crystal forms were found to be suitable for X-ray diffraction analysis. Crystals of the tetragonal form, grown in the presence of 25% polyethylene glycol 4000 and 0.25 M-NaCl at pH 6.6, were chosen for further analysis. These crystals belong to the space group P4(1)(3)2(1)2 with refined lattice constants of a = 94.8 A and c = 49.0 A, indicating a cell content of one monomer per asymmetric unit of the crystal. The crystals diffract to a resolution of 2.2 A.

Cloning, Molecular↗
PubMed1992

Purification and characterization of a NADH oxidase from the thermophile Thermus thermophilus HB8.

A NADH oxidase has been purified from the extreme thermophile Thermus thermophilus HB8 by several chromatographic steps. The purified enzyme was essentially homogeneous as judged by gel electrophoresis under denaturing conditions and by determination of the N-terminal amino acids sequence. It is a monomeric flavin-adenine-dinucleotide-containing flavoprotein with an apparent molecular mass of 25 kDa and an 1:1 ratio of FAD to the polypeptide chain. The purified enzyme catalyzes the oxidation of reduced NADH or NADPH with the formation of H2O2. The apparent Km values for NADH and NADPH are 4.14 microM and 14.0 microM (pH 7.2 at room temperature), respectively, with a sixfold greater kcat/Km values for NADH compared to NADPH. The enzyme uses O2 as an electron acceptor in the presence of either FAD, riboflavin 5'-phosphate or riboflavin as cofactor. In addition, the enzyme is able to catalyze electron transfer from NADH to various other electron acceptors (methylene blue, cytochrome c, p-nitroblue tetrazolium, 2,6-dichloroindophenol and potassium ferricyanide), even in the absence of flavin shuttles. No significant inhibition of the NADH oxidoreductase activity by superoxide dismutase was observed with these artificial electron acceptors, indicating that electron transfer occurs mainly from NADH directly to the electron acceptors, not via O2- as an intermediate. The purified NADH oxidase exhibits highest activity at pH 5.0 and is stable at elevated temperatures of up to 80 degrees C.

Amino Acid Sequence↗
PubMed1992

Purification and properties of lipase from Penicillium simplicissimum.

A Penicillium simplicissimum strain has been found to produce an inducible extracellular lipase. Triolein was the best inducer for the enzyme production with the highest activity being achieved after 48 h of incubation. The purified lipase showed a molecular weight of 56,000 by SDS-PAGE. The enzyme exhibited a high ratio of apolar amino acids. The lipase was stable in the pH range of 5-7 and at 50 degrees C for 15 min. The optimum assay conditions were 37 degrees C and pH 5.0. The enzyme showed a high stability in water immiscible organic solvents. Lipase from P. simplicissimum is nonspecific and hydrolyses each of the three bonds of triacylglycerols.

Amino Acids↗
PubMed1992

Solubilized substrates for the on-line measurement of lipases by flow injection analysis during chromatographic enzyme purification.

A flow injection analysis (FIA) system for the on-line measurement of lipases in chromatographic processes has been developed. The photometrically detectable substrates para-nitrophenylpalmitate, S,O,O'-tripropyryl-1-thioglycerol, and 1,2-O-dilauryl-rac-glycero-3-glutaric-resorufinester were investigated. Different detergents and qualities of assay emulsions were tested for optimal results in FIA applications. Emphasis was placed on increasing the stability of the assay emulsion. Lipases of different origin and specificity were detected. The linear detection range was adapted to the requirements of the chromatographic purification procedures. The connection of the FIA with a fast protein liquid chromatography system permitted the automatization of lipase purification by monitoring protein content, salinity, and enzyme activity of the effluent from column chromatography.

Animals↗
PubMed1989

The effect of recombinant human granulocyte-macrophage colony-stimulating factor on neutropenia and related morbidity in chronic severe neutropenia.

STUDY OBJECTIVE: To define the clinical and hematologic effects of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on patients with chronic severe neutropenia. DESIGN: Open-label, phase II study of rhGM-CSF. SETTING: Inpatient hematology and surgery clinic at a university medical center. PATIENTS: Four consecutive patients with chronic severe neutropenia, which in two cases was complicated by severe infection, in one case by perianal fistula, and in one case by complete rectal prolapse. Two patients had chronic idiopathic neutropenia; one patient had congenital neutropenia (myelokathexis); and one patient had autoimmune neutropenia. INTERVENTIONS: The rhGM-CSF was given intravenously or subcutaneously at starting dosages of 150 to 1000 micrograms/m2 body surface area.d for 12 to 14 consecutive days. Two patients received a second course of daily rhGM-CSF treatment after a nontreatment interval of 14 to 20 days. MEASUREMENTS AND MAIN RESULTS: In all four patients, the absolute neutrophil counts increased from less than 0.25 x 10(9)/L to 3.2 to 19.2 x 10(9)/L within 2 weeks of beginning rhGM-CSF therapy. Two patients had life-threatening infections that resolved during therapy. The two other patients had major ano-rectal surgery during rhGM-CSF treatment and had no postoperative infections. CONCLUSIONS: In patients with chronic neutropenia, rhGM-CSF may increase neutrophil counts. This therapy may be a useful adjunct to antibiotic therapy for patients with infection and perioperatively for patients having anorectal surgery.

Adult↗
PubMed1986

The acidic peptide-specific type II protein kinases from the nucleus and the cytosol of porcine liver are distinct.

The second messenger-independent acidic peptide-specific protein kinase II (casein kinase II) from the cytosol of porcine liver has been purified to apparent homogeneity by using DEAE-cellulose, hydroxyl apatite, and phosphocellulose chromatography. The native enzyme has an apparent Mr of 150,000. After sodium dodecyl sulfate-gel electrophoresis a band of Mr = 39,000 and a slightly diffuse band of Mr = 27,000 were found indicating an alpha 2 beta 2 structure of this protein kinase. A thorough comparison with the corresponding enzyme from the nucleus was performed. The two enzymes differ in the subunit composition, as the nuclear enzyme is composed of subunits with a Mr of 95,000; they further differ in the heparin sensitivity and binding to blue dextran-Sepharose. Distinct differences in their nucleotide binding sites were found upon mapping with ATP analogs, although both enzymes utilize ATP as well as GTP. On the other hand, both enzymes phosphorylate identical sites in the casein variants beta A2 and alpha S1B at comparable rates. These results demonstrate for the first time the existence of distinct nucleus and cytoplasm specific type II "casein kinases".

Adenosine Triphosphate↗
PubMed1984

[Paraneoplastic syndromes].

Paraneoplasia has come to denote those tumor activities not caused within an organism directly by invasion, obstruction, or by the tumor burden itself. PSN research has yielded best results through the examination of those hormones produced by the tumor, esp. the pro-ACTH and its functionally active subgroups, furthermore the ADH, gonadotropins, HPL, STH, prolactine etc. Frequently very special features have been found to characterize this disease which have been published in detail. In addition to this, several differentiating PNS have been described without having been sufficiently defined, esp. those concerning the nervous system, the haematopoesia , the kidneys, the skin and the gastrointestinal system. In very rare cases there has been a mention or different characteristic syndromes that have come to be assigned to special kinds of tumors.

Central Nervous System Diseases↗
PubMed1984

[Monitoring of heart function in the treatment with cardiotoxic cytostatic drugs].

UNLABELLED: It is the purpose of this paper to show the concept of noninvasive assessment of cardiomyopathy (CM) in cytostatic treatment, esp. with daunorubicin A (A). Our follow-up study during therapy with A shows 255 patients, examined by ECG, by systolic time intervals (STI)-PEP/LVET (normal value less than or equal to 0.44) and PEPI (normal value less than or equal to 148 ms) by echocardiography (UCG) with measurement of shortening fraction (SF), normal value less than or equal to 30% and in 6 cases by microcatheter with exercise test. RESULTS: (1) ECG does not predict CM. (2) 23 patients (8%) had abnormal SF in UCG, 6 patients of these having no symptoms of cardiac failure. These patients were examined by microcatheter, all 6 having abnormal values during exercise. So all patients with abnormal SF had objective signs of latent or over CM. (3) PEP/LVET was abnormal in all patients with CM, but false positive in 22% of all investigations, mostly by shortening of LVET. PEPI, abnormal in all patients with CM, was false positive only in 8.8. UCG is the most specific noninvasive method for assessment of CM in cytostatic treatment. STI are less specific, but highly sensitive to CM and therefore a useful screening method. PEPI gives the highest specificity, allowing a better selection than PEP/LVET. STI in contrast to UCG can easily be obtained outside cardiologic centers, ie., in the oncologic department itself. UCG by cardiologic units are needed only about 10-15% of investigations. If all values are abnormal, cardiotoxic treatment should be stopped, even when patients are asymptomatic.

Cardiomyopathies↗