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Biomedical subjects

F Schneider

Publications and source records attributed to F Schneider.

At least 253 records · Page 14Linked to original sources
PubMed1990

[Morphologic and morphometric analysis of atheromatous changes in the aorta in silibinin-treated cholesterin-fed rabbits].

Authors studied the effect of Silibinin of antioxidative effect on cholesterin sclerosis of rabbits. Qualitative analysis of aorta sections, macroscopic and microscopic morphometric examination of aorta were the applied methods. Their results seem to show that Silibinin has a favourable influence on cholesterin sclerosis. According to their opinion only joint use of qualitative and quantitative macroscopic and microscopic methods can provide basis for really accurate judgment of any atheromatose change.

Animals↗
PubMed1990

[The effect of steroid hormone doses after ovariectomy on the peripheral hormone processes and uterine development in gilts. 2. Effects on gilts during early pregnancy].

Experimental studies were conducted into ovariectomized pregnant gilts to establish effects of exogenic hormone administration, with endogenic ovarian steroids excluded, upon uterus and fetus development as well as on hormone levels in blood plasma, endometrium, and allantoic fluid. Hormone concentrations in blood plasma were found to depend clearly on hormone doses applied after ovariectomy to preserve pregnancy. 2 to 3 weeks of smooth gravidity, following ovariectomy, were ensured on the 6th or 14th day after KB1 by daily application of very low doses of progesterone only (80 mg) or in combination with estrogens, the ratio being 480:1.

Animals↗
PubMed1990

[The hormone profile in the blood plasma of heifers after cycle synchronization with prostaglandin F2alpha].

Highly sensitive radio-immuno assay (RIA) was used for 21 days to study the curves of several steroid hormones, progesterone (P), oestradiol 17 beta (E2), and testosterone (T), as well as of luteinizing hormone (LH) in peripheral blood of six heifers to which oestrus had been induced by prostaglandin F2 alpha. The validity of the authors' RIA for P, E2, and T determination in blood plasma was positively verified by two reliability criteria, correctness and accuracy, as well as by comparative determinations, using reference methods. Only four of the six heifers returned to oestrus, within 21 days from first oestrus induction. A typical cycle-related curve of the P concentration in peripheral blood with peak values between the 13th and 17th days of cycle (15-26 nmol/l) was recorded from four animals. The peak values of pre-ovulatory E2 and LH were between 33.0 and 53.2 pmol/l or between 19.5 and 52.5 micrograms/l. Some of the T rises in peripheral blood were in parallel to E2 concentrations. All hormone curves are presented in detail and are discussed in relation to clinico-physiological findings.

Animals↗
PubMed1989

[Porphyria cutanea tarda and lupus erythematosus].

We observed three patients with lupus erythematosus and porphyria cutanea tarda manifesting itself simultaneously or subsequently. The possible coincidence of the two diseases might be the consequence of immunological communities indicated on the assumption of a genetically coined hepatic uroporphyrinogen decarboxylase defect. The treatment of the lupus erythematosus can be performed according to corresponding observations of the course according to general acknowledged principles including the administration of cytostatic drugs, if the chloroquine phosphate therapy which is clearing up the porphyria cutanea tarda is beginning with low dosages. The fluorescence of the fresh kidney bioptate under long-wave UV-light in porphyria cutanea tarda is referred to for the first time.

Adult↗
PubMed1989

Presynaptic alpha 2-adrenoceptors modulate the release of [3H]noradrenaline from rat spinal cord dorsal horn neurones.

Slices of the dorsal half of the rat spinal cord were used to investigate the existence of a noradrenergic feedback modulation of noradrenaline release. After crude preparation of the vertebral column, the spinal cord was ejected by hydraulic pressure and transverse slices were cut. These were preincubated with [3H]noradrenaline during 0.1 Hz electrical stimulation and then superfused and stimulated electrically for two periods. The stimulation-evoked release of [3H]noradrenaline was Ca2+-dependent and tetrodotoxin-sensitive. Pretreatment of the animals with the noradrenergic neurotoxin, DSP-4, reduced the tritium content in the slices and the stimulation-evoked release to less than 10% of the controls. Clonidine (0.01-1 microM) inhibited the evoked overflow by 60% maximally and yohimbine (0.1-1 microM) enhanced it by 160% maximally. The effects of clonidine were antagonized by yohimbine. These results provide evidence that noradrenaline release from spinal cord slices is controlled by an alpha 2-adrenoceptor-mediated, negative feedback mechanism.

Animals↗
PubMed1989

A mammary-derived growth inhibitor (MDGI) related 70 kDa antigen identified in nuclei of mammary epithelial cells.

The aim of the present study was to investigate the expression of the mammary-derived growth inhibitor (MDGI) and the subcellular localization of MDGI-related antigens in bovine mammary glands. Cell-free translation of poly(A+) = RNA, immunoprecipitation with rabbit anti-MDGI-antibodies, and estimation of the relative contents of MDGI by a radioimmunoassay in mammary tissue of different functional states revealed that the 13 kDa MDGI was dramatically increased in terminally differentiated mammary tissue compared with the proliferating tissue from pregnant animals. To address the question of tissue localization, polyclonal anti-MDGI antibodies and antibodies directed against a synthetic peptide corresponding to residues 69 to 78 of MDGI were used. Western blotting of tissue fractions revealed the cytosolic and microsomal localization of MDGI. Additionally, both types of antibodies detected a 70-kDa antigen in the nuclear fraction of differentiated mammary glands. Salt extraction and DNase I digestion of isolated nuclei, as well as chromatin purification, indicated an association of the 70-kDa antigen with the chromatin. By means of the immunogold technique, MDGI-related antigens were localized within euchromatic nuclear regions of epithelial cells in the intact differentiated mammary gland. The immunostaining was markedly diminished in the proliferating tissue. This finding raises the possibility that MDGI and the 70-kDa antigen influence cell proliferation by acting on gene expression within the nuclei of mammary glands.

Animals↗
PubMed1989

Effect of two week lymphatic occlusion on the mechanical properties of dog femoral arteries.

In order to study the long-term effect of impaired lymphatic drainage on the mechanical properties of the arterial wall, cylindrical femoral artery segments from 10 mongrel dogs after 2 weeks of hindlimb lymphatic occlusion were subjected to in vitro mechanical test and compared with the contralateral, sham-operated segments. Smooth muscle contraction was induced by norepinephrine (7.4 X 10(-6) M) and smooth muscle relaxation by papaverine (1.6 X 10(-4) M). As a result of 2 weeks of lymphatic occlusion, wall thickness increased from 243 +/- 18 to 343 +/- 35 microns (P less than 0.02), inner radius decreased from 1.69 +/- 0.11 to 1.42 +/- 0.12 mm (P less than 0.01) and elastic modulus decreased from 1.23 X 10(6) to 0.55 X 10(6) N/m2 (P less than 0.01), when determined at 100 mm Hg (13.3 kPa) intraluminal pressure and with relaxed smooth muscle. The contractile apparatus was able to produce active strain in the vessels with lymphostasis and at physiological pressures not significantly different from the controls (0.89 +/- 0.02 vs. 0.91 +/- 0.02), but at significantly lower levels of tangential stress. Active stress decreased significantly. This study shows that a reorganization of the vessel wall mechanical force-bearing elements occurs in lymphostasis, which, in some respects, resembles the mechanical alterations found in different forms of atherosclerosis.

Animals↗
PubMed1989

Sialic acid, galactose and fucose on the surface of Ehrlich ascites tumor cells grown in glucose-free medium in the presence of uridine.

1) The content and accessibility of terminal sialic acid and galactose residues as well as the incorporation of [3H]fucose into glycoconjugates were determined in 48-h cultures of Ehrlich ascites tumor cells in a glucose-free medium supplemented with uridine, a compound which can fulfil the necessary functions of glucose. 2) Sialic-acid residues accessible to sialidase cleavage were reduced from 695 +/- 80 nmol/10(9) cells (controls) to 284 +/- 22 nmol/10(9) cells (43% of controls). In situ labeling using periodate oxidation followed by sodium borotritiide reduction revealed a tritium incorporation of 47 +/- 11% that of controls (= 4.1 x 10(5) cpm/mg protein). 3) Labeling of galactose residues of 80-90% of that of controls was achieved after treatment of the cells with galactose oxidase/sodium borotritiide. A nearly six-fold enhancement of tritium incorporation into galactose of control cells was observed after sialidase/galactose oxidase treatment and sodium borotritiide reduction (1.5----8.8 x 10(5) cpm/mg protein); only a 3.6-fold increase (1.2 x 10(5)----4.3 x 10(5) cpm/mg protein) was found with glucose-free cultured cells. It is concluded that the galactose content of the cell surface is reduced to about 50% of controls. 4) The incorporation of tritium into acid-insoluble precipitate after 24 h incubation with [3H]fucose and the activity of the acid-soluble fraction were enhanced by about 85% as compared to controls. The pattern of inhibition by tunicamycin of [3H]fucose uptake and incorporation was the same in glucose-containing standard medium and in glucose-free uridine medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Investigations on the function of creatine kinase in Ehrlich ascites tumor cells.

1. Growth and viability of in vitro cultured Ehrlich ascites tumor cells are not significantly impaired by exogenous creatine up to 40mM. Retardation of cell growth by higher concentrations depends on cell density. 2. Ehrlich cells grown in the presence of high concentrations of creatine accumulate creatine phosphate to high levels (up to 23 nmol/10(6) cells in the presence of 40mM creatine). 3. A nearly complete interruption of glycolytic ATP production or inhibition of the oxidative ATP synthesis reduces the maximal creatine to about 40-50% of controls. 4. Studies on the intracellular distribution of creatine kinase have shown, that the enzyme is only associated with the mitochondrial fraction. Titration of isolated mitochondria with digitonin revealed that the activity is located in the inter-membrane space and partly bound to the outer site of the inner membrane. 5. By growth of Ehrlich cells in creatine-free medium it is possible to obtain "creatine phosphate-depleted" cells (creatine phosphate less than 10% of controls). The growth of creatine phosphate-depleted cells as compared to controls is significantly reduced under energetic stress situations. The protein synthesis of these cells after an energetic stress (lack of glucose and oxygen) is significantly reduced as compared to creatine phosphate containing cells. 6. It is concluded that in these cells creatine kinase/creatine phosphate is a thermodynamic buffer system and not part of an energy shuttle as is postulated for muscle cells.

Adenosine Triphosphate↗
PubMed1989

[The effect of steroid hormone administration after ovariectomy on the peripheral hormone kinetics and uterine development in gilts. 1. Effects on cyclic gilts].

Studies were conducted into effects of various steroid hormone doses on uterus development and steroid levels in blood plasma and endometrium of ovariectomized cyclic gilts. Differences were found to exist between experimental and control animals with regard to uterus weight and length in the wake of ovariectomy and steroid treatment. Steroid concentrations in blood plasma exhibited discernible changes, depending on dosage. As to endometrial hormone concentrations, some dependence on applied progesterone doses was recordable only from oestrone sulphate levels.

Animals↗
PubMed1989

[Intima and subintimal space as the site of the initial lesions in the formation of arteriosclerosis].

Experiments were conducted under various conditions, including hypoxaemia, endothelial damage by means of balloon catheterisation, cholesterol feeding, administration of lipofundin, and obstruction of lymphatic drainage. As a result, damage to endothelial cells along with increase in permeability is considered to be the initial process in the development of arteriosclerosis. This is followed by penetration of plasma, formation of fibrinoid in the subendothelial layer and in the media as well as by a number of cellular phenomena, the latter including adhesion of thrombocytes, penetration of monocytes into the intimal space, and proliferation of smooth muscle cells. Cellular, fibromuscular lesion is, eventually, caused as a result of those processes.

Arteries↗
PubMed1989

[Experimental studies on the stimulation of prenatal development in swine by PMSG treatment in early pregnancy. 2. Analytic studies of hormones in young sows after PMSG treatment on the 11th day of pregnancy].

Tens gilts received 400 I.U. of Pregmagon on the 11th day of pregnancy (day of KB2 = 1 day of pregnancy), while 8 sows were used as controls. Blood was sampled 4 times a day between the 11th and 25th day of pregnancy, with an indwelling catheter being used. Progesterone, oestradiol-17 beta, and luteinising hormone were radio-immunologically determined. The hormone profiles of pregnant sows were found to differ unambiguously from those of non-pregnant animals for both concentrations and frequencies. They were indicative of close correlations and time links of gonadotrophic and steroid hormones in early pregnancy and in oestrus. PMSG treatment in pregnancy resulted in increase in the oestradiol-17 beta concentration and attenuation in pulsatile luteinising hormone release at the time of implantation. Progesterone concentrations in peripheral blood were not affected by PMSG injection.

Animals↗
PubMed1989

Production and characterization of four monoclonal antibodies specific for human interferon-alpha-1 and -alpha-2.

Four monoclonal antibodies against HuIFN-alpha-1 and -alpha-2 were produced by the lymphocyte hybridoma technique. The screening for monoclonal anti-IFN antibodies was performed by two different procedures permitting the detection of neutralizing and non-neutralizing antibodies. The first antibody screening in the supernatants of hybridoma clones was carried out by an immunodot ELISA using a novel chromogen, 2-bromo-1-naphthol, for the immunoperoxidase reaction. The second screening was performed with a solid-phase bioassay. The monoclonal antibodies IIG11 and IVH2 react specifically with HuIFN-alpha-1 independently of its origin, natural or recombinant. The mAb IIG11 recognizes also an epitope on a 27 kDa interferon, probably HuIFN-alpha-8. The mAb IIG7 binds to HuIFN-alpha-2 only, whereas the mAb IIB2 binds to HuIFN-alpha-2 and also to the 27 kDa interferon and to a 25 kDa interferon, not yet further characterized. These antibodies can be used successfully for immunopurification as well as for quantification of the corresponding interferons.

Antibodies, Monoclonal↗
PubMed1988

Hepatic and bile porphyrins in patients with protoporphyria and liver failure.

The livers of patients who have protoporphyria and hepatic failure contain large amounts of pigment crystals. Two such patients underwent liver transplantation, providing the opportunity to identify the pigment crystals. Portions of liver were digested enzymically, sedimented through a sucrose gradient, treated with 1% sodium dodecylsulfate, and centrifuged to purify the crystals. Spectrophotometric and high-performance liquid chromatography analysis demonstrated them to be composed of protoporphyrin. Bile samples were obtained from the 2 patients, 4 other patients who did not have liver disease, and 10 control subjects. The porphyrin concentrations in bile from the 6 patients were significantly increased above controls (range 254-7884 micrograms/dl compared with 11-109 micrograms/dl). The ratio of protoporphyrin to bile acid in bile distinguished the 2 patients with advanced liver disease (3105 and 2756 micrograms/mmol) from the 4 patients without liver disease (range 61-926 micrograms/mmol). Thus, analysis of bile from patients with protoporphyria may help in evaluating their hepatobiliary status.

Adult↗
PubMed1988

Decreased vascular contraction and elastic stiffening after intramural lymphostasis.

Lymphatic obstruction leads to leakage of protein into the vessel wall that is coupled with edema formation and smooth muscle degeneration. To clarify the mechanical effect of these changes, lymphatic trunks, draining the femoral artery, were stained with Evans blue and then ligated in dogs anesthetized with pentobarbital sodium (n = 11). Sham ligation was performed on these lymphatic trunks in the opposite hindlimb (n = 11). Three days later, 7- to 30-mm segments of both femoral arteries were studied in vitro. Intraluminal pressure was cycled between 5 and 250 mmHg at 5 mmHg/s, and external diameter was recorded in both relaxed and activated (norepinephrine, 3 x 10(-5) mol/l) state of smooth muscle. Mechanical parameters were computed for 10-mmHg pressure increments. After lymphatic obstruction, strain energy density and distensibility of the passive wall components as well as isobaric active tangential strain were decreased by a maximum of 27, 59, and 54%, respectively; active tangential stress and elastic modulus, as a function of tangential stretch, was decreased by a maximum of 62%, and increased by 61%, respectively. These results indicate that short-term intramural lymphostasis reduces smooth muscle reactivity and induces vascular stiffening.

Animals↗