Biomedical subjects

U Berger

Publications and source records attributed to U Berger.

At least 19 recordsLinked to original sources

PubMed1992

Ubiquinone biosynthesis. Cloning of the genes coding for chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyl transferase from Escherichia coli.

Chorismate pyruvate-lyase activity was detected in extracts of Escherichia coli. 4-Hydroxybenzoate was identified as the product of the enzymatic reaction by chemical derivatization and GC-MS analysis. The ubiC gene, coding for the chorismate pyruvate-lyase, was cloned and sequenced. The molecular weight of the gene product was calculated as 18,776 Da and confirmed by expression of the protein in E. coli minicells. The ubiA gene, coding for the 4-hydroxybenzoate octaprenyl transferase, was identified by sequence homology and complementation of a ubiA- strain. It is located directly downstream of ubiC in a typical operon structure.

Alkyl and Aryl Transferases↗

PubMed1992

Inhibition of protein N-glycosylation by 2-deoxy-2-fluoro-D-galactose.

The effects of 2-deoxy-2-fluoro-D-galactose (dGalF) on N- and O-glycosylation of proteins was studied in rat hepatocyte primary cultures and in human monocytes. In hepatocytes, dGalF at concentrations of 1 mM or higher completely inhibited N-glycosylation of alpha 1-antitrypsin and alpha 1-acid glycoprotein, whereas 4 mM-2-deoxy-D-galactose (dGal) only slightly impaired N-glycosylation. In monocytes, 1 mM- or 4 mM-dGalF blocked N-glycosylation of alpha 1-antitrypsin and of interleukin-6, while O-glycosylation of interleukin-6 remained unaffected. In monocytes, dGal had no effect on protein N-glycosylation. Addition of uridine effectively prevented the UTP deficiency induced by dGalF, but had no effect on the inhibition of protein N-glycosylation by dGalF. Using 19F-n.m.r. spectroscopy, 2-deoxy-2-fluoro-D-galactose 1-phosphate (dGalF-1-P), UDP-dGalF and UDP-dGlcF could be identified as the major metabolites of dGalF in hepatocytes as well as in monocytes. In conclusion, compared with dGal, dGalF is a more efficient inhibitor of protein N-glycosylation. The effect is not caused by the depletion of UTP induced by dGalF, but rather by metabolites of dGalF. dGalF is metabolized not only in hepatocytes but also in peripheral blood monocytes, which can be used for ex vivo studies of disturbances in D-galactose metabolism.

Animals↗

PubMed1992

Transport and in vivo elimination of cysteinyl leukotrienes.

Transport processes control not only synthesis and release of LTC4 but also the elimination and excretion of LTC4 and its metabolites. (i) A primary-active ATP-dependent export carrier mediates the release of LTC4 from a leukotriene-generating cell, as exemplified by mastocytoma cells, and as measured in mastocytoma plasma membrane vesicles (2). (ii) Release of cysteinyl leukotrienes into the blood circulation is followed by a rapid elimination with an initial half-life of 38 sec in rats and 4.0 min in man, as measured with the labeled, representative LTC4 catabolite, N-acetyl-LTE4. (iii) 11C-labeled N-acetyl-LTE4 can serve for non-invasive studies on cysteinyl leukotriene elimination and excretion by the liver and kidney in the intact organism using positron emission tomography. An impairment of leukotriene transport from the liver across the canalicular membrane into bile, studied in mutant rats and in extrahepatic cholestasis, leads to a compensatory diversion of cysteinyl leukotriene elimination to the kidney. N-Acetyl-LTE4 labeled with a short-lived positron-emitting isotope provides quantitative insight into the pathways of cysteinyl leukotriene elimination in vivo. (iv) Cysteinyl leukotriene export from the liver into bile is mediated by an ATP-dependent primary-active export carrier. This decisive step in cysteinyl leukotriene elimination has been characterized in hepatocyte canalicular membrane vesicles (3). The leukotriene exporter is deficient in transport mutant rats. The leukotriene carrier is distinct from other ATP-dependent export carriers identified in this membrane domain, such as the ATP-dependent bile salt export carrier (25) and the multidrug export carrier (27).

Adenosine Triphosphate↗

PubMed1992

Histochemistry of the porcine pilosebaceous unit.

The present study describes lectin and immunoreactivity in the pilosebaceous unit of porcine skin. Complex carbohydrates of mucin and biantennary Man/Gluc types were distributed among hair follicle epithelia (hair root sheaths, cuticula, shaft, and shaft matrix). Sebaceous glands expressed biantennary Man/Gluc carbohydrates and GalNAc residues. The expression of simple-type and epidermis-like keratins was confirmed by immunohistochemistry with monoclonal antibodies. Filaggrin-positive cells were found in the keratinizing zone of Henle's layer in anagen follicles. The innermost layer of the outer hair root sheath was stained with antibodies against the epidermal growth factor-receptor, keratin 10 and Ki67 antigen. The differences to humans were remarkably small.

Animals↗

PubMed1992

Tissue expansion in pig skin--a histochemical approach.

In the present study, a porcine model for controlled skin expansion was investigated to improve our understanding of epidermal and vascular responses following stretching. The model is of outstanding importance not only for the clinical use of tissue expansion but provides interesting data for skin physiology and oncology, too. Thirteen out of 15 animals, who underwent silicone tissue expander implantation showed good clinical results. In all of them, skin biopsies were taken at the end of a controlled tissue expansion procedure (final expander volumes 350 or 500 ccm): one tissue specimen was obtained from the centre of the expanded skin area and a second from the neighbouring but nonexpanded skin. The tissue specimens were immediately frozen in liquid nitrogen and processed to 4 microns thick acetone-fixed frozen sections. Lectin histochemistry and immunohistology were performed using the following techniques: direct and indirect immunofluorescence technique (DIFT, IIFT), immunoperoxidase technique (POX) with either 3,3'-diamino-benzidine (DAB) or 3-amino-9-ethyl-carbazole (AEC). The histochemical findings were supplemented by measurements of the number of vital epidermal cell layers, the epidermal thickness (microns), and the papillary vascular count per visual field. There was a significant diminuation of the vascular count (mean +/- S.D. = 55.0% +/- 12.5%; U-test: p less than 5%). By immunohistochemistry, a loss of the basal cell reactivity for the following antibodies was noted: ACAM (against calmodulin), K 8.12 (against keratins 13 +/- 16) and A51-B/H4 (against keratins 8, 14, 18). There was a remarkable increase of filaggrin expression in the uppermost spinal cell layers in expanded skin, which was most pronounced in those specimens with the shortest interval to the last fluid injection into the expander. We gained no evidence for alterations of the expression of suprabasal epidermal keratins, lectin binding sites (UEA I, PNA, ConA, WGA), and vascular lectin- and immunoreactivity due to tissue expansion. The subdermal capsule, which had formed around the silicone expander, was strongly vimentin-reactive. In conclusion, controlled tissue expansion is capable to change the basal cell phenotype--a feature which is shared with a number of conditions with increased proliferative activity and with the epidermis covering different skin tumours. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation. Furthermore, the porcine skin is a reliable model for studying physiology and pathophysiology of human skin.

Animals↗

PubMed1992

Onset and duration of the effects of three antihistamines in current use--astemizole, loratadine and terfenadine forte--studied during prolonged, controlled allergen challenges in volunteers.

In a three-way, double-blind, crossover study the onset of action and effects at the end of the dosing interval of 10 mg/day astemizole, 10 mg/day loratadine and 120 mg/day terfenadine forte given for 3 days to six atopic volunteers were assessed using the Vienna challenge chamber (VCC). With each treatment, two long-term pollen challenges were performed in the VCC: the first to assess the onset of action started 1 h before the first dose and lasted continuously for 5 h; the second to assess the effects at the end of dosing took place 21 h after the last of the three doses and lasted 3 h. All three drug treatments initiated 1 h after the beginning of challenge with grass pollen reversed the adverse effects of challenge on the subjective symptoms (runny, blocked or itchy nose, sneezing, itchy eyes, tears) and the objective parameters (nasal secretions, nasal resistance, nasal flow, flow increase, nasal peak flow) within 1-3 h. The mean time to onset of action was 107 min for astemizole, 117 min after treatment for loratadine and 153 min for terfenadine forte. During the second allergen challenge, 21-24 h after intake, astemizole consistently provided better protection for all parameters than did loratadine or terfenadine forte; however the differences were not statistically significant.

Adult↗

PubMed1992

[Experimental studies on tissue expansion in reconstructive surgery].

In the present study, a porcine model for controlled tissue expansion was investigated under the conditions or formation of extreme enlarged randomized flaps. The circulatory disturbances and necrotizing processes to be expected were evaluated immediately after flap formation by intravenous injection of fluorescein dye to predict the surviving area. Lectin histochemistry and immunohistology were performed using either the direct and indirect immunofluorescence technique (DIFT, IIFT) or immunoperoxidase techniques (POX). Over all, the expanded randomized flaps healed without complications in all animals. The acute randomized flaps showed clear necroses already after 10 days. In the thoracic area they averaged 60.3% (SD = 8.17%) and in the pelvic area 47.32% (SD = 14.11%) of the flap. The use of the fluorescein dye test in the present experiment demonstrated that the flap surviving area is significantly greater than the flap staining area. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation.

Animals↗

PubMed1991

ATP-dependent transport of taurocholate across the hepatocyte canalicular membrane mediated by a 110-kDa glycoprotein binding ATP and bile salt.

Direct photoaffinity labeling of liver plasma membrane subfractions enriched in sinusoidal and canalicular membranes using [35S]adenosine 5'-O-(thiotriphosphate) ([35S]ATP gamma S) allows the identification of ATP-binding proteins in these domains. Comparative photoaffinity labeling with [35S]ATP gamma S and with the photolabile bile salt derivative (7,7-azo-3 alpha, 12 alpha-dihydroxy-5 beta-[3 beta-3H]-cholan-24-oyl-2'- aminoethanesulfonate followed by immunoprecipitation with a monoclonal antibody (Be 9.2) revealed the identity of the ATP-binding and the bile salt-binding canalicular membrane glycoprotein with the apparent Mr of 110,000 (gp110). The isoelectric point of this glycoprotein was 3.7. Transport of bile salt was studied in vesicles enriched in canalicular and sinusoidal liver membranes. Incubation of canalicular membrane vesicles with [3H] taurocholate in the presence of ATP resulted in an uptake of the bile salt into the vesicles which was sensitive to vanadate. ATP-dependent taurocholate transport was also observed in membrane vesicles from mutant rats deficient in the ATP-dependent transport of cysteinyl leukotrienes and related amphiphilic anions. Substrates of the P-glycoprotein (gp170), such as verapamil and doxorubicin, did not interfere with the ATP-dependent transport of taurocholate. Reconstitution of purified gp110 into liposomes resulted in an ATP-dependent uptake of [3H]taurocholate. These results demonstrate that gp110 functions as carrier in the ATP-dependent transport of bile salts from the hepatocyte into bile. This export carrier is distinct from hitherto characterized ATP-dependent transport systems.

ATP-Binding Cassette Transporters↗

PubMed1991

Immunocytochemical determination of estrogen receptor, progesterone receptor, and 1,25-dihydroxyvitamin D3 receptor in breast cancer and relationship to prognosis.

We have determined the estrogen receptor, progesterone receptor (PR), and 1,25-dihydroxyvitamin D3 receptor content of 136 breast carcinomas by an immunocytochemical method. The presence of the three receptors was not related to clinical features of presentation such as T-stage or to age or menopausal status. However, each of the three receptors has a different relationship to the course of the disease in these patients. The presence of PR was significantly associated with an improved overall survival (chi 2 = 4.61, P = 0.032). Patients whose tumors contained immunocytochemically detectable 1,25-dihydroxyvitamin D3 receptor had a longer disease-free interval than those patients with negative tumors (chi 2 = 4.01, P = 0.045). The presence of estrogen receptor and PR were found to correlate with an increased survival between relapse and death (P = 0.027 and P = 0.09, respectively). The relationships between estrogen receptor and PR and prognosis are more apparent when the degree of cell staining is considered. Combined receptor analysis improves our ability to predict the course of the disease and may therefore facilitate better management of the patients.

Adult↗

PubMed1991

Partial purification, properties, and kinetic studies of UDP-glucose:p-hydroxybenzoate glucosyltransferase from cell cultures of Lithospermum erythrorhizon.

A glucosyltransferase, which catalyzed the transfer of glucose from UDP-glucose (UDPG) to p-hydroxybenzoate (PHB) in cell cultures of Lithospermum erythrorhizon Sieb. et Zucc., Boraginaceae, was purified 219-fold by ammonium sulfate fractionation and chromatography on DEAE-Sephacel, Sephadex G-150, and phenyl-Sepharose Cl-4B. p-Hydroxybenzoic acid O-beta-D-glucoside (PHB-glc) was identified as a product of the enzymatic reaction. This glucosyltransferase has a molecular weight of 47,500 Da, an isoelectric point at pH 5.0, and a pH optimum of 7.8. The enzyme does not sediment at 100,000g. Enzyme activity did not require metal cofactors. The enzyme was highly specific for p-hydroxybenzoate (Km 0.264 mM) and UDP-glucose (Km 0.268 mM). Initial velocity studies suggest that the enzyme reaction mechanism is a sequential rather than a ping-pong mechanism. Product inhibition patterns are consistent with an ordered sequential bi-bi mechanism, where UDPG is the first substrate to bind to the enzyme and UDP the final product released. The data indicate the formation of a dead-end complex between PHB-glc and the enzyme. Uncompetitive inhibition by the substrate PHB can be put down to the formation of an abortive complex between E-UDP and PHB.

Glucosyltransferases↗

PubMed1991

Bone marrow micrometastases in primary breast cancer: prognostic significance after 6 years' follow-up.

Using an antiserum to epithelial membrane antigen we have screened multiple bone marrow aspirates from 350 patients with primary breast cancer taken at the time of initial surgery. 89 (25%) patients were found to have micrometastases and their presence was related to pathological size (P less than 0.01), the presence of peritumoral vascular invasion (P less than 0.001), and positive lymph nodes (P less than 0.005) but not menopausal status. At a median follow-up of 76 months (range 34-108) 107 patients had relapsed with distant metastases. 48% (43 of 89) of these patients had micrometastases initially compared with 25% (64 of 261) who did not (P less than 0.005). The test predicts for relapse in bone (P less than 0.01) and other distant sites excluding bone (P less than 0.001) and is associated with a shorter overall survival (P less than 0.005). We conclude that the detection of micrometastases signals a high likelihood of early relapse and decreased survival in breast cancer.

Adult↗

PubMed1991

Immunohistochemistry of porcine skin.

The present paper reports immunohistological findings in porcine skin, which were obtained by use of mono- and polyclonal antihuman antibodies and either alkaline phosphatase anti-alkaline phosphatase (APAAP) or peroxidase (POX) technique. Epidermal staining was observed with antibodies to keratins (K 8.12, RSKE 60), filaggrin, and calmodulin (ACAM). Staining of connective tissue and vessels was achieved using antibodies to vimentin (V9(1)), collagen type IV, and fibronectin. In general, these antibodies gave a staining pattern similar to that of normal human skin. The similarities of immunoreactivity to poly- and monoclonal antihuman antibodies in porcine and human skin render porcine skin a reliable model in biomedical research.

Animals↗

PubMed1991

Photoaffinity labeling of leukotriene binding sites in hepatocytes and hepatoma cells.

The method of direct photoaffinity labeling in the frozen state using the leukotrienes as suitable photolabile compounds may serve to identify and characterize polypeptides which interact with these eicosanoids during their hepatobiliary transport and metabolism. Furthermore, it will be a helpful technique to evaluate changes in the cell-specific protein pattern during neoplastic dedifferentiation of hepatocytes.

Affinity Labels↗

PubMed1991

[Nevoid bundle hairs].

We report on two cases of naevoid bundle hair of the scalp. The clinical picture is characterized by an abnormal grouping of hairs emerging from one follicle ostium. The hairs arise from separate follicles but fuse into a common outer hair root sheath in the above the sebaceous gland. The outer hair root sheath is characterized by its abnormal reactivity with monoclonal antibodies against keratin but normal reactivity with anti-filaggrin. Naevoid bundle hair is thought to be an atavistic hair growth pattern.

Antibodies, Monoclonal↗

PubMed1990

Metabolism and actions of 2-deoxy-2-fluoro-D-galactose in vivo.

The synthetic D-galactose analog 2-deoxy-2-fluoro-D-galactose (dGalF) offers unique advantages for studies of the D-galactose pathway by non-invasive techniques using 19F-NMR spectroscopy or positron emission from the 18F-labeled compound. The metabolism of 2-deoxy-2-fluoro-D-galactose was studied in rodents using the unlabeled, the 18F-labeled, and the 14C-labeled D-galactose analog. Analyses for the metabolites of 2-deoxy-2-fluoro-D-galactose were performed by HPLC, enzymatic methods, and 19F-NMR spectroscopy in vivo and in vitro. The metabolism of 2-deoxy-2-fluoro-D-galactose was most active in the liver which took up the major part of the administered dose of the 14C-labeled D-galactose analog, but renal excretion was also pronounced. This was confirmed by in vivo scanning of the rat using the 18F-labeled sugar (1.5 microCi/g; 25 nmol/g) and examination by positron-emission tomography and gamma camera. The dose dependence of the levels of the hepatic metabolites of 2-deoxy-2-fluoro-D-galactose was investigated for doses between 25 nmol/g body mass and 1 mumols/g body mass. After 1 h, the major part of the acid-soluble uracil nucleotides consisted of UDP-2-deoxy-2-fluoro-D-hexoses when the dose was at least 0.1 mumols/g. With higher doses, 2-deoxy-2-fluoro-D-galactose 1-phosphate became the predominant initial metabolite. After a dose of 1 mumols/g 2-deoxy-2-fluoro-D-galactose 1-phosphate accumulated rapidly (5.3 +/- 0.4 mumols/g liver after 30 min) followed by the formation of UDP-2-deoxy-2-fluoro-D-galactose and UDP-2-deoxy-2-fluoro-D-glucose (0.7 +/- 0.1 mumols/g and 1.8 +/- 0.1 mumols/g, respectively, after 5 h). The diversion of uridylate, due to the accumulation of UDP-2-deoxy-2-fluoro-D-hexoses, was associated with a rapid depletion of hepatic UTP, UDP-glucose, and UDP-galactose. The UTP content was decreased to 11 +/- 6% of normal within 15 min after administration of 2-deoxy-2-fluoro-D-galactose at a dose of 1 mumols/g. The UTP-depleting action was minimal, however, at a dose of 25 nmols/g or less, indicating that interference in uridylate metabolism would be negligible at the doses required for positron-emission tomography of the liver using the 18F-labeled compound. At higher doses, the UTP deficiency induced by 2-deoxy-2-fluoro-D-galactose could be useful in the chemotherapy of D-galactose-metabolizing tumors such as hepatocellular carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

In vivo metabolism and UTP-depleting action of 2-deoxy-2-fluoro-D-galactose.

The metabolism of 2-deoxy-2-fluoro-D-galactose (dGalF) was studied in rodents using HPLC, enzymatic methods, and 19F-NMR spectroscopy in vivo and in vitro. The liver took up the major part of the administered dose of the 14C-labeled D-galactose analog. This was confirmed in vivo by use of the 18F-labeled sugar (1.5 mCi/kg; 25 mumol/kg) and examination by positron emission tomography. After a dose of 1 mmol/kg, dGalF-1-phosphate accumulated rapidly (5.3 +/- 0.4 mmol/kg after 30 min), followed by formation of UDP-dGalF and UDP-2-deoxy-2-fluoro-D-glucose (0.7 +/- 0.1 and 1.8 +/- 0.1 mmol/kg, respectively, after 5 hr). Good quantitative agreement was obtained between the measurements by HPLC and enzymatic analyses and by 19F-NMR. The noninvasive in vivo 19F-NMR technique is particularly advantageous, since it allows the simultaneous analysis of all dGalF metabolites. The diversion of uridylate, due to the accumulation of UDP-2-deoxy-2-fluoro-D-hexoses, was associated with a rapid depletion of hepatic UTP, UDP-glucose, and UDP-galactose. The UTP content was decreased to 11 +/- 6% of normal within 15 min after administration of dGalF at a dose of 1 mmol/kg. The UTP-depleting action was minimal, however, at a dose of 25 mumol/kg or less, indicating that interference in uridylate metabolism will be negligible at the doses required for positron emission tomography of the liver using the 18F-labeled compound. At higher doses the UTP deficiency induced by dGalF may be useful in the chemotherapy of D-galactose-metabolizing tumors such as hepatocellular carcinoma. At moderate doses of dGalF, 19F-NMR spectroscopy in vivo or in vitro could be used to pinpoint defects of the enzymes that cause galactosemia, i.e. of galactokinase, uridyltransferase, or 4-epimerase.

Animals↗

PubMed1990

Pulmonary lymphangioleiomyomatosis and steroid receptors. An immunocytochemical study.

Estrogen and progesterone receptors were demonstrated immunocytochemically in the lung tissue of two cases of pulmonary lymphangioleiomyomatosis. In one case both receptors were localized in the proliferative smooth muscle nodules and diffusely in the interstitial tissue in close proximity to the muscle. The pulmonary tissue in the other case contained the estrogen receptor only. The authors conclude that the response to hormonal treatment seen in this disease might be optimized in the future by monitoring for the presence of steroid hormone receptors.

Adult↗

PubMed1989

Comparison of an immunocytochemical assay for progesterone receptor with a biochemical method of measurement and immunocytochemical examination of the relationship between progesterone and estrogen receptors.

Using a rat monoclonal antibody raised against human progesterone receptor (PR) we have developed an immunocytochemical technique to detect PR in human normal and malignant breast tissue and have compared the distribution of this with that obtained by the conventional dextran-coated charcoal steroid-binding assay. Immunoreactive PR was detected exclusively in the nuclei of epithelial cells in 29/51 (56.9%) of breast cancers studied. There was an excellent correlation between the immunocytochemical and dextran-coated charcoal techniques, with concordance in 43/51 (84.3%) cases [regression coefficient (Spearman) = 0.78; P less than 0.001]. The relationship between PR and estrogen receptor (ER) was also examined immunocytochemically using a monoclonal antiserum to ER. Twenty-eight out of 51 (54.9%) tumors were positive for both receptors and 13/51 (25.5%) negative for both. ER-positive, PR-negative tumors were found in 9/51 (17.6%) cases whereas only one case (2%) was PR-positive, ER-negative.

Antibodies, Monoclonal↗