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Biomedical subjects

H Geyer

Publications and source records attributed to H Geyer.

At least 91 records · Page 5Linked to original sources
PubMed1986

In vitro responsiveness of ovarian epithelial carcinomas to endocrine therapy.

As previously reported, ovarian epithelial carcinomas may respond to endocrine therapy. We examined the direct effect of progesterone, medroxyprogesteroneacetate, gestoneron, 17-beta-estradiol, tamoxifen, 4-OH-tamoxifen, or N-desmethyltamoxifen on the proliferative capacity of ovarian carcinoma cells by means of the colony assay described by Hamburger and Salmon. The growth rate of 25 tested tumors (ascitic fluid, primary tumor, metastases) was 68%. The plating efficiency was 0.078%. Beside the drug testing estrogen and progesterone receptor levels were determined. The inhibition of colony survival was slightest with 17-beta-estradiol, more pronounced with medroxyprogesteroneacetate, gestoneron, N-desmethyltamoxifen, and progesterone, and greatest with 4-OH-tamoxifen and tamoxifen. Significant and dose-dependent inhibition of greater than 70% was observed with tamoxifen and 4-OH-tamoxifen in 80% of the tested tumors. There was no significant correlation between the in vitro responsiveness and the level of hormonal act not only via an estrogen receptor but also via an antiestrogen-binding site.

Adenocarcinoma↗
PubMed1986

Bioconcentration potential of organic environmental chemicals in humans.

A list of environmental chemicals detectable in adipose tissue and/or milk of non-occupationally exposed humans is presented. Besides their physiochemical properties (n-octanol/water partition coefficient and water solubility), their acceptable daily intake (ADI) values, production figures, fate in the environment, concentrations in human adipose tissue, and data from total diet studies from market basket investigations are given. Average bioconcentration factors (BCF) of polychlorinated biphenyls (PCBs), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), DDT, hexachlorobenzene (HCB), dieldrin, hexachlorocyclohexane isomers (alpha-HCH, beta-HCH, gamma-HCH, delta-HCH), pentachlorophenol (PCP), and 3,5-di-tert-butyl-4-hydroxytoluene (BHT) in human adipose tissue are calculated. The bioconcentration factors (wet wt basis) of these compounds are between 3 and 47 times higher in humans than in rats. The environmental chemicals are divided into three groups in respect to their bioconcentration factors in human adipose tissue: group I, high BCF (greater than 100); group II, medium BCF (10-100); and group III, low BCF (less than 10). The bioconcentration factors are useful for hazard assessment of chemicals to humans.

Adipose Tissue↗
PubMed1986

Purification of pyruvate kinase isoenzymes type M1 and M2 from dog (Canis familiaris) and comparison of their properties with those from chicken and rat.

Pyruvate kinase isoenzymes type M1 and M2 from dog muscle, lung and tumor have been isolated. The K0.5 for phosphoenol pyruvate have been determined to be 0.04 mM for dog muscle type M1, 0.24 mM for lung type M2 and 0.28 mM for tumor type M2 isoenzymes. The activator constant ka of L-serine is 240 nM from lung and 70 nM from tumor isoenzyme. Consistent with the assumption of a special form of pyruvate kinase M2 in dog tumor cells different isoelectric points and amino acid compositions have been found for the isoenzymes of lung and tumor.

Amino Acids↗
PubMed1985

Influence of tissue heterogeneity on the determination of steroid receptors in breast cancer.

Biochemical determination of hormone receptors in carcinomas is influenced by the potential heterogeneity of the tissue samples. In order to check this, samples of 16 breast cancers were divided into 6 segments. These segments were alternately examined for their ratio of tumor tissue to connective tissue ("percentage of carcinoma") or for the content of estrogen and progesterone receptors. Only 3 of the tumors were homogeneous, and 9 of the heterogeneous tissues had hormone receptors. The segment with the maximum "percentage of carcinoma" was adjacent to that with the peak value of hormone receptors in all but 1 tissue. The same applied to the minima. The maximum and minimum values of estrogen and progesterone receptors were located within the same segment in all but one tissue sample. The results demonstrated that biochemical assay of hormone receptors is reliable. A reduction of the sample volume does not enhance the precision of the receptor assay, since it increases the possibility of a false negative result.

Adenocarcinoma, Mucinous↗
PubMed1984

Major oligosaccharides in the glycoprotein of Friend murine leukemia virus: structure elucidation by one- and two-dimensional proton nuclear magnetic resonance and methylation analysis.

The highly microheterogeneous, N-glycosidically linked oligosaccharides in the glycoproteins of Friend murine leukemia virus (as produced by Eveline cells) were liberated with endo-beta-N-acetylglucosaminidase H and by alkaline hydrolysis. They were fractionated (as desialylated oligosaccharitols) by gel filtration and by concanavalin A affinity chromatography, and the major fractions were analyzed by methylation-gas chromatography-mass spectrometry, by digestion with exoglycosidases, and, especially, by one- and two-dimensional proton nuclear magnetic resonance spectroscopy. Guidelines for qualitative and quantitative analysis of complex oligosaccharide mixtures by NMR were worked out and the results compared with those obtained by methylation analysis. It was found that these major fractions consist of bi-, tri-, and tetraantennary oligosaccharitols of the "complex" type (comprising a minority of species with N-acetyllactosamine repeating units), which are, in part, substituted by nonreducing terminal Gal alpha (1----3) and/or bisecting GlcNAc beta (1----4) residues.

Acetylglucosaminidase↗
PubMed1984

Structure of the oligosaccharides sensitive to endo-beta-n-acetylglucosaminidase H in the glycoprotein of Friend murine leukemia virus.

The surface glycoprotein (mixture of isoglycoproteins with Mr 69 000 and 71 000) was isolated from the particles of Friend murine leukemia virus, and was successively digested with protease and with endo-beta-N-acetylglucosaminidase from Streptomyces griseus. Roughly 20% (w/w) of the carbohydrates in this glycoprotein were thus released, and they were fractionated by high-performance liquid chromatography after reduction with KB3H4/NaBH4. The radioactive oligosaccharitol fractions obtained were analyzed by exoglycosidase digestion, by acetolysis, and, after permethylation, by fast atom-bombardment mass spectrometry, as well as by capillary gas-liquid chromatography/mass spectrometry following hydrolysis, reduction and peracetylation. Around 85% (mol/mol) of the endo-H-sensitive viral glycans were thus found to be oligomannosidic oligosaccharitols of size classes Man5GlcNAcOH, Man6GlcNAcOH, Man8GlcNAcOH, Man7GlcNAcOH, and Man9GlcNAcOH (in order of prevalence), and the major structural isomers of each size class were identified. About another 15% (mol/mol) of the oligosaccharitols were shown to be of the 'mixed type', comprising mainly four species in which the Man(alpha 1----6)-branch of the Man alpha 1----6 (Man alpha 1----3) Man beta 1----4GlcNAcOH core is substituted by one or two additional alpha-mannoses, while the Man(alpha 1----3)-branch carries an N-acetyllactosamine unit substituted by sialic acid, or by Gal(alpha 1----3).

Acetylglucosaminidase↗
PubMed1984

Activities of proteinases and of a proteinase B inhibitor in tumors of the human uterus.

The activities of an acid proteinase, of an alkaline proteinase, of a lysine aminopeptidase and of a proteinase B inhibitor were measured in benign and malignant tumors of the human uterus. In carcinomas of the corpus uteri the activity of the acid proteinase (cathepsin D) was increased compared to normal endometrium. This could probably be the result of cell destruction within the tumor. In leiomyomas of the uterus the activities of the alkaline proteinase, of the lysine aminopeptidase, and of the proteinase inhibitor were decreased compared to the normal myometrium. These results suggest that a decrease in the rate of degradation of myofibrillar proteins relative to the rate of protein synthesis may be responsible for the growth of myomas.

Aminopeptidases↗
PubMed1984

Polychlorinated biphenyls (PCBs) in the marine environment, particularly in the Mediterranean.

Polychlorinated biphenyls (PCBs) possess a low water solubility, a high n-octanol/water partition coefficient, and a high persistence, particularly those which are highly chlorinated. Because of these properties they are bioaccumulated in many organisms in the environment. PCBs are still manufactured industrially and used in the Mediterranean countries (e.g., Italy, Spain, and France). Production figures for these countries and for the FRG, the United Kingdom, and the United States between 1973 and 1979 are given. The concentrations of PCBs in marine air, water, sediments, microplankton , algae, mussels, fish, and other marine organisms including seabirds from the Mediterranean area are reviewed and compared with PCB concentrations in marine samples from non-Mediterranean regions. Levels of PCBs in seawater are highest in the western and central Mediterranean. The data for mussels and fish give a clear indication that the PCB levels are higher in the Northwest and the Tyrrhenian Sea than in the eastern Mediterranean. The FDA in June 1979 set 2 mg/kg as the temporary maximum concentration for PCBs in fish and shellfish. The PCB residues in some fish from the northwestern Mediterranean and Tyrrhenian Sea and in some mussels from the Adriatic Sea are higher than this limit. The amount of PCBs ingested via food by the Mediterranean population is unknown.

Air Pollutants↗
PubMed1984

C-reactive protein serum concentrations in well-trained athletes.

Previously it had been shown that there is a sharp increase in C-reactive protein (CRP) serum concentration during the first few days after severe exercise. To evaluate the effect of physical training on the CRP levels, a sensitive enzyme immunoassay was developed and used to assess the basal CRP concentrations in 356 male and 103 female athletes, who trained at least 4 times per week in various disciplines, in 45 male and 40 female untrained controls, and in 35 elderly coronary patients. In male athletes the lowest CRP values were found in swimmers (median: 102 ng/ml, n = 59), which were significantly lower (P less than 0.001) than those of male controls (median: 502 ng/ml, n = 45). The CRP concentrations in rowers (median: 260 ng/ml, n = 108) were also significantly lower (P less than 0.01) than in the control group. CRP levels in middle- and long-distance runners (median: 315 ng/ml, n = 53), racing cyclists (median: 620 ng/ml, n = 111), and soccer players (median: 660 ng/ml, n = 25) did not differ significantly from those of the controls. In female athletes the lowest CRP concentrations were also found in swimmers (median: 110 ng/ml, n = 49), which were significantly lower (P less than 0.001) than those of the female controls (median: 396 ng/ml, n = 40). Female middle- and long-distance runners (n = 36) and female rowers (n = 18) had median CRP values of 250 and 285 ng/ml, respectively. This results suggest that training induces a suppressive effect upon CRP, responsible for the low serum levels in athletes (particularly swimmers) when compared to controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Fibrin-fibrinogen degradation products and pregnancy-specific beta 1-glycoprotein (SP 1) in normal and pathological pregnancies].

Fibrin-fibrinogen degradation products and SP 1 were measured in about 150 women with normal pregnancies. The mean levels of both parameters rose up to term. In 13 normal pregnancies the SP 1 course never decreased. Elevated levels of SP 1 were measured in 4 out of 10 cases of mild gestosis. In 11 cases of severe gestosis, however, 7 had increased values. A decrease of elevated levels correlated to a clinical deterioration. SP 1 was normal in the most cases of severe gestosis, but a fall of SP 1 indicated an impaired placental function resulting in small-for-date baby or imminent foetal asphyxia. The measurements of fibrinogen degradation products and of the course of SP 1 are helpful in the diagnosis of gestosis.

Female↗
PubMed1984

[Steroid hormone receptors in ovarian carcinomas and their clinical significance].

Concentrations of estrogen (ER) and progesterone receptors (PR) were determined in 197 malignant tumors of the ovary. The frequency of receptors was the same as in breast cancer (ER 64%, PR 49%). In non-epithelial ovarian carcinomas steroid receptors were found only in granulosa cell tumors. PR was found less often in metastases than in primary tumors and after chemotherapy. Premenopausal tumors were more often PR-positive than postmenopausal carcinomas (71% versus 52%). ER were always constant. PR-negative tumors seemed to respond better to chemotherapy than positive tumors. Patients with PR-negative ovarian carcinomas seem to have a better prognosis than patients with PR-positive cancer. The clinical stage or the histological grade of the tumors did not correlate to the receptor status.

Adult↗