Gamow-Teller and spin-dipole strength in 90Zr(n,p) at 65 MeV.
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Journal Article↗
Biomedical subjects
A Klein
Publications and source records attributed to A Klein.
Conserved gene structures and expression signals in methanogenic archaebacteria.
A comparative analysis of cotranscribed gene clusters comprising the structural genes mcrA, mcrB, mcrC, mcrD, and mcrG was carried out in three species of methanogens. mcrA, mcrB, and mcrG are the structural genes for the three subunits of methyl coenzyme M reductase, while the two other genes encode polypeptides of unknown functions. The degree of conservation of the mcr gene products among different species of methanogens varies. No correlation was found between the conservation of the G+C contents of the homologous genes and of the amino acid sequences of their products among the different bacteria. The comparison of RNA polymerase core subunit genes of Methanobacterium thermoautotrophicum as evolutionary markers with their equivalents in Escherichia coli, Saccharomyces cerevisiae, and Drosophila melanogaster showed that homologous polypeptide domains are encoded by different numbers of genes suggesting gene fusion of adjacent genes in the course of evolution. The archaebacterial subunits exhibit much stronger homology with their eukaryotic than with their eubacterial equivalents on the polypeptide sequence level. All the analyzed genes are preceded by ribosome binding sites of eubacterial type. In addition to known putative promoter sequences, conserved structural elements of the DNA were detected surrounding the transcription initiation sites of the mcr genes.
Amino Acid Sequence↗
Albumin and the unique pattern of inhibitors of cortisol catabolism by lymphocytes in serum of cancer patients.
We have shown previously that sera of cancer patients (CPS) possess ethanol-extractable substances which can inhibit the catabolism of cortisol by lymphocytes (CCL). In the present study an attempt was made to purify the inhibitory material by gel filtration. Chromatography of normal serum and CPS on a Sephadex G-10 column showed one peak of CCL inhibition with control serum and two peaks with CPS. The one peak which was common to both sera appeared with the void volume and was identified as albumin. The second peak which was present with CPS only, appeared at a molecular weight range of 300-350 daltons. We postulate that CPS may contain a relatively high concentrations of small molecules which are not bound to proteins and which might modulate the normal function of the immune system.
Chromatography, Gel↗
Periampullary neoplasms in von Recklinghausen's disease.
A case of neurofibromatosis is reported in a patient who was initially seen with obstructive jaundice caused by a carcinoid tumor originating from the ampulla of Vater. An extensive review of the literature suggests that patients with von Recklinghausen's disease are at significant risk for periampullary neoplasms of neural-crest and non-neural-crest origin. The tendency of those tumors to arise from the ampulla of Vater has diagnostic and therapeutic implications.
Adult↗
On the autocrine growth regulation of Morris hepatoma cells.
Chemically induced, transplantable Morris hepatoma 7777 cells (MH) were examined for their anchorage-dependent and anchorage-independent growth properties. MH cells were found to grow on solid surface in a density-dependent manner, with respect to serum factors and gelatinization. The correlation between anchorage independent growth of MH cells and agar or serum concentrations in the culture medium was described. The ability of MH cells to stimulation of soft agar colony formation of NRK-49F indicator cells in coculture assay was presented. Autocrine control of proliferation of MH cells by TGFs-like factor(s) was suggested.
Animals↗
[Cannulation of the internal jugular vein using 2 ultrasonic technics. A comparative controlled study].
The internal jugular vein (IJV) is a common access route to the central venous system. Anatomical landmarks (group I) are normally used for localization of the IJV. We have compared this method with two other methods based on ultrasonic waves to identify the IJV and the carotid artery (CA) (even in atypical positions). We employed an ultrasound Doppler device in group II and a real-time ultrasonograph in group III. Central venous catheters were placed into the right IJV by the Seldinger technique. The IJV could be located in all patients with both ultrasound methods, but the course of the IJV could only be identified by ultrasonography. For this reason, the direction of the IJV was classified as "typical" in 80% of group I, in 85% of group II, but in only 45% of group III. No intergroup differences were found with respect to the number of punctures (mean value 1.6 +/- 0.83) and the incidence of complications. The time required to locate the site and direction of puncture increased with technical sophistication. There was, however, no difference in the total time for catheter placement, because puncture was performed faster when aided by sonography. In four patients in groups I and II, in whom attempts to puncture the IJV had not been successful, this could subsequently be achieved with ultrasonographic aid. One patient (group I) displayed a hematoma following inadvertent puncture of the CA. In one patient in group II the IJV and CA could not be distinguished as one was overlying the other. The echocamera provided improved localization of the IJV and the CA in comparison with the Doppler ultrasound.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Isolation and structural characterization of low-molecular-mass monosialyl oligosaccharides derived from respiratory-mucus glycoproteins of a patient suffering from bronchiectasis.
The carbohydrate chains of the respiratory-mucus glycoproteins of a patient suffering from bronchiectasis due to Kartagener's syndrome were released by alkaline borohydride treatment. Low-molecular-mass, monosialyl oligosaccharide-alditols were isolated by anion-exchange chromatography and fractionated by consecutive straight-phase high-performance liquid chromatography (HPLC) on a silica-based alkylamine column, and reverse-phase HPLC on a silica-based octadecyl column, respectively. The structures of the oligosaccharidealditols were determined by 500-MHz 1H-NMR spectroscopy in combination with sugar composition analysis. The 24 structures established range in size from disaccharides to heptasaccharides. Novel oligosaccharides obtained from the bronchiectasis mucus glycoproteins are: (formula; see text) 23 of the 24 monosialyl oligosaccharides characterized can be conceived of as extensions of neutral oligosaccharides purified from the bronchial mucus of this patient [Klein, A. et al. (1988) Eur. J. Biochem. 171, 631-642; Breg, J. et al. (1988) Eur. J Biochem. 171, 643-654]. The sialic acid residue was found to occur either in alpha (2----3)- or alpha (2----6)-linkage to a galactosyl residue or in alpha (2----6)-linkage to GalNAc-ol.
Amino Acids↗
Relatedness of archaebacterial RNA polymerase core subunits to their eubacterial and eukaryotic equivalents.
The sequence of the genes encoding the four largest subunits of the RNA polymerase of the archaebacterium Methanobacterium thermoautotrophicum was determined and putative translation signals were identified. The genes are more strongly homologous to eukaryotic than to eubacterial RNA polymerase genes. Analysis of the polypeptide sequences revealed colinearity of two pairs of adjacent archaebacterial genes encoding the B" and B' or A and C genes, respectively, with two eubacterial and two eukaryotic genes each encoding the two largest RNA polymerase subunits. This difference in sequence organization is discussed in terms of gene fusion in the course of evolution. The degree of conservation is much higher between the archaebacterial and the eukaryotic polypeptides than between the archaebacterial and the eubacterial enzyme. Putative functional domains were identified in two of the subunits of the archaebacterial enzyme.
Amino Acid Sequence↗
Conserved elements in the transcription initiation regions preceding highly expressed structural genes of methanogenic archaebacteria.
The sequences of the intergenic regions of the strongly expressed genes encoding methyl CoM reductase in three different methanogenic archaebacteria were determined and the 5'-ends of the transcripts were mapped. After alignment, consensus sequences were found which are located both upstream and downstream of the transcription starts. They correspond, in part, to those previously characterized as putative elements of archaebacterial promoter sequences. In addition, bending of the DNA in front of the transcription start sites was shown in two cases and a characteristic common DNA structure immediately downstream of the 5'-end of the transcript was discovered. This structure was also found in the corresponding regions of previously described genes in methanogens. Our results suggest that both sequence and structural information may have roles in the initiation of transcription of protein encoding genes of these archaebacteria.
Base Composition↗
Primary structure of neutral oligosaccharides derived from respiratory-mucus glycoproteins of a patient suffering from bronchiectasis, determined by combination of 500-MHz 1H-NMR spectroscopy and quantitative sugar analysis. 1. Structure of 16 oligosaccharides having the Gal beta(1----3)GalNAc-ol core (type 1) or the Gal beta(1----3)[GlcNAc beta(1----6)]GalNac-ol core (type 2).
Carbohydrate chains of respiratory-mucus glycopeptides from a patient (blood group O) suffering from bronchiectasis with a Kartagener's syndrome have been released by alkaline borohydride treatment. Application of high-performance liquid chromatography using subsequently two silica columns, one bonded with aminopropyl groups and the other with octadecyl groups, afforded 39 neutral fractions; 35 oligosaccharide-alditol structures have been characterized by employing 500-MHz 1H-NMR spectroscopy in conjunction with sugar analysis. Here, 16 oligosaccharide structures, possessing a core consisting of Gal beta(1----3)GalNAc-ol branching through a GlcNAc residue linked beta(1----6) to the GalNAc residue (core type 2 or core type 1, respectively), are described. Ten oligosaccharide-alditols with these types of cores (2, 3, 10a, 14, 7, 11a, 15a, 16a, 12 and 16c) have been identified previously in human bronchial mucins of patients suffering from cystic fibrosis [Lamblin, G., Boersma, A., Lhermitte, M., Roussel, P., Mutsaers, J.H.G.M., Van Halbeek, H. and Vliegenthart, J.F.G. (1984) Eur. J. Biochem. 143, 227-236]. Of the remaining six compounds, one is a partial structure of oligosaccharides previously described: (Formula: see text). The structures 17a and 20 contain the Y determinant, i.e., Fuc alpha(1----2)Gal beta(1----4)[Fuc alpha(1----3)]GlcNAc beta(1----). High-resolution 1H-NMR spectroscopy is able to distinguish whether the Y determinant is beta(1----3) or beta(1----6) linked in such oligosaccharide-alditols.
Bronchiectasis↗
Primary structure of neutral oligosaccharides derived from respiratory-mucus glycoproteins of a patient suffering from bronchiectasis, determined by combination of 500-MHz 1H-NMR spectroscopy and quantitative sugar analysis. 2. Structure of 19 oligosaccharides having the GlcNAc beta(1----3)GalNAc-ol core (type 3) or the GlcNAc beta(1----3)[GlcNAc beta(1----6)]GalNAc-ol core (type 4).
A pool of neutral carbohydrate chains was prepared from respiratory mucins of a patient suffering from bronchiectasis. Fractionation by HPLC led to 35 smaller-size oligosaccharide-alditols; the structure of 16 oligosaccharide-alditols with core type 1 or type 2 has been established (Klein, A., Lamblin, G., Lhermitte, M., Roussel, P., Breg, J., Van Halbeek, H. & Vliegenthart, J.F.G., preceding paper in this journal). In this second part, we identified 19 oligosaccharide-alditols possessing core types 3 and 4. Nine of the structures (1, 5, 9, 6, 10b, 13, 19, 15b and 18.1) have been described previously to be present in cystic fibrosis mucins [Lamblin, G., Boersma, A., Lhermitte, M., Roussel, P., Mutsaers, J.G.H. M., Van Halbeek, H. & Vliegenthart, J.F.G. (1984) Eur. J. Biochem. 143, 227-234]. The remaining ten are new structures isolated from bronchial mucins; they are all extensions of the above-mentioned nine oligosaccharides. These compounds are octassaccharide-alditols containing the Y determinant together with the H determinant of either backbone-type 1 or 2, and partial structures thereof: (Formula: see text) and 21b, which is 23c without Fuc alpha(1----3), 18.2, which is 23c without any Fuc in the 6-branch, and 22b, which is 23c without Fuc in the 3-branch.
Bronchiectasis↗
Application of plasminogen polymorphism to forensic hemogenetics.
Plasminogen polymorphism (PLG) has attained considerable importance in forensic hemogenetics. PLG comprises two common, codominant autosomal alleles, PLG*A and PLG*B, more than 18 variants, and the silent allele PLG*Q0. Isoelectric focusing followed by functional or immunochemical detection seems to be the optimal method for the determination of phenotypes. PLG*A is the most common allele in all populations, having its highest frequency in Mongoloids, Amerindians and Eskimos, the lowest in Caucasoids. The functionally inactive plasminogen M5 so far has been seen exclusively in Japanese individuals. Silent PLG alleles were only observed in the heterozygous state. No clear differences in functional activity or plasma level could be ascertained for any of the other allotypes. PLG polymorphism is now widely used for many haemogenetic investigations. From the allele distribution in European Caucasoids a single exclusion chance of 17.2% for non-fathers in paternity testing may be calculated. The major prerequisites of a new genetic marker in the parentage expertise, established Mendelian inheritance, favorable distribution of common alleles, low frequency of silent alleles, and simple reproducible typing technology, are fulfilled.
Alleles↗
Comparative analysis of genes encoding methyl coenzyme M reductase in methanogenic bacteria.
The sequence of the gene cluster encoding the methyl coenzyme M reductase (MCR) in Methanococcus voltae was determined. It contains five open reading frames (ORF), three of which encode the known enzyme subunits. Putative ribosome binding sites were found in front of all ORFs. They differ in their degrees of complementarity to the 3' end of the 16 S rRNA, which is discussed in terms of different translation efficiencies of the respective genes. The codon usage bias is different in the subunit encoding genes compared with the two other ORFs in the cluster and two other known genes of Mc. voltae. This is interpreted in terms of increased translational accuracy of the highly expressed MCR subunit genes. The derived polypeptide sequences encoded by the five ORFs of the MCR cluster were compared to those of the respective genes in Methanobacterium thermoautotrophicum Marburg and Methanosarcina barkeri. Conserved regions were detected in the enzyme subunits, which are candidates for factor binding domains. Conserved hydrophobic sequences found in the alpha and beta subunits are discussed with respect to the membrane association of the enzyme.
Amino Acid Sequence↗
Failure of PAF-acether to induce in vivo neutrophil migration.
The ability of PAF-acether (platelet activating factor, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine) to induce neutrophil migration was tested in the peritoneal cavities of rats and guinea-pigs and in rat skin air pouches. PAF-acether, at doses of 2 and 5 micrograms per animal, did not promote significant neutrophil migration. The ability of PAF-acether antagonists to inhibit carrageenin induced neutrophil migration in rat abdominal cavities was also investigated. Carrageenin is a substance described to cause the release of endogenous PAF-acether. Neutrophil migration was not affected by PAF-antagonists. These observations challenge the possible role of PAF-acether as a neutrophil chemotactic factor in vivo.
Animals↗
The effect of nonviral liver damage on the T-lymphocyte helper/suppressor ratio.
In the present investigation an attempt was made to ascertain whether nonviral liver impairment in rats affects the THelper/TSuppressor ratio. Two hepatotoxic agents were used: (i) galactosamine (GA), which causes a drug-induced hepatitis-like damage, and (ii) orotic acid (OA), which induces fatty changes. Since these two substances act as antidotes to one another they were administered to rats either separately or simultaneously. GA caused severe liver damage documented by a 104-, 48-, and 1.6- fold rise in the plasma concentrations of ALT, AST, and ALP and by multiple foci of hepatocyte necrosis. This was followed by a drop in TH/TS ratio from 2.25 observed in the controls to 0.89 in the GA-treated rats. All of these phenomena were prevented by concurrent administration of GA and OA. OA alone did not show an effect on the liver with respect to changes in plasma enzyme concentrations and by light microscopic analysis. However, OA caused a drop in the TH/TS ratio from 2.25 to 1.55. Neither GA nor OA produced a change in TH/TS ratios in in vitro experiments.
Animals↗
The complexity of mucins.
Mucins represent the main components of gel-like secretions, or mucus, secreted by mucosae or some exocrine glands. These high-molecular-weight glycoproteins are characterized by the large number of carbohydrate chains O-glycosidically linked to the peptide. The determination of mucin molecular weight and conformation has been controversial for several reasons: 1) the methods used to solubilize mucus and to purify mucins are different and 2) the molecules have a strong tendency to aggregate or to bind to other molecules (peptides or lipids). Recently, electron microscopy has shown the filamentous shape of most mucins and their polydisperse character which, in some secretions, might correspond to a polymorphism of the peptide part of these molecules. The recent development of high pressure liquid chromatography and high-resolution proton NMR spectroscopy has allowed major progress in the structural study of mucin carbohydrate chains. These chains may have from 1 to about 20 sugars and bear different antigenic determinants, such as A, B, H, I, i, X, Y or Cad antigens. In some mucins, such as human respiratory mucins, the carbohydrate chain diversity is remarkable, which raises many questions. Mucins are molecules located at the interface between mucosae and the external environment. The carbohydrate chain diversity might allow many interactions between mucins and microorganisms and play a major role in the colonization or the defense of mucosae.
Animals↗
[Regulation of the fetoplacental unit. 1. Comparison of the suppressive effect of cortisol and cortisone on estradiol synthesis].
The present study compares the negative feed back action of cortisol and cortison on oestriol production in late human pregnancy. 10 women from the 38th to 40th week of gestation volunteered in this study. All had uncomplicated courses of pregnancy and delivered healthy babies at term. 5 patients received a continuous infusion of 100 mg Cortisol from 10 a.m. to 12 a.m. To the other 5 patients 100 mg Cortison were infused during the same period. Blood specimens (5 ml) were drawn in 60 and 30 minutes intervals from 8 a.m. to 5 p.m. Plasma levels of unconjugated oestriol were measured by radioimmunoassay. The suppression of oestriol levels was nearly identical in both groups: After Cortisol oestriol concentrations decreased from 17.1 +/- 9.1 ng/ml to 6.0 +/- 1.2 ng/ml (p less than 0.001) and after Cortison from 15.5 +/- 5.8 ng/ml to 5.9 +/- 1.8 ng/ml (p less than 0.001), respectively. According to these results the placental metabolism of maternal cortisol to cortison does not impair the negative feed back action of this hormone on the foetal hypothalamus-hypophysis-system.
Estradiol↗
[Regulation of the fetoplacental unit. 2. Circadian changes in the sensitivity of the fetal hypothalamo-hypophyseal system for the feedback effect of cortisol].
The present study investigates the significance of a circadian changing sensitivity on the feed back action of cortisol for the foetal hypothalamic hypophyseal system. 9 patients with uncomplicated courses of pregnancy in the 37th to 40th week volunteered in this study. All of them delivered healthy babies at term. 5 patients received a continuous infusion of 0.25 mg ACTH1-24 (Synacthen) in the morning from 10 a.m. to 4 p.m. (group I). To 4 patients an analogous ACTH infusion was applied in the evening from 8 p.m. to 2 a.m. (group II). Blood specimens (5 ml) were drawn from 8 a.m. to 5 p.m. in group I and from 5 p.m. to 3 a.m. in group II in 60 and 30 minutes intervals, respectively. Free plasma oestriol was measured by radioimmunoassay, total plasma cortisol by the protein binding method. In group I cortisol increased from 294.3 +/- 52.9 ng/ml to 774.5 +/- 170 ng/ml, whereas oestriol decreased from 13.1 +/- 6.1 ng/ml to 6.8 +/- 2.1 ng/ml (p less than 0.001). In group II cortisol rose from 267.5 +/- 76.2 ng/ml to 1010 +/- 284 ng/ml, whereas oestriol levels were suppressed from 21.7 +/- 10.5 ng/ml to 10.8 +/- 3.2 ng/ml (p less than 0.001). Two hours after starting ACTH infusion rising cortisol and falling oestriol concentrations were negatively correlated (r = -0.9657, p less than 0.001 in the morning; r = -0.9119, p less than 0.001 in the evening). Plasma oestriol levels were in the evening suppressed on an average of 10.9 ng/ml and exceeded the oestriol decrease in the morning (6.3 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)
Adrenocorticotropic Hormone↗