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Biomedical subjects

A Scheidegger

Publications and source records attributed to A Scheidegger.

16 recordsLinked to original sources
PubMed2001

Ni clay neoformation on montmorillonite surface.

Polarized extended X-ray absorption fine structure spectroscopy (P-EXAFS) was used to study the sorption mechanism of Ni on the aluminous hydrous silicate montmorillonite at high ionic strength (0.3 M NaClO4), pH 8 and a Ni concentration of 0.66 mM. Highly textured self-supporting clay films were obtained by slowly filtrating a clay suspension after a reaction time of 14 days. P-EXAFS results indicate that sorbed Ni has a Ni clay-like structural environment with the same crystallographic orientation as montmorillonite layers.

Journal Article↗
PubMed1996

[Ambulatory surgery clinic in a public general hospital. Organization and results].

In surgery a day care clinic is defined as an institution in which patients undergo elective operations the day of their admission and are discharged within 24 h after surgery. An important goal of day care surgery is to avoid unnecessary hospitalisations however providing the patient with the same quality of treatment and personal satisfaction. This presentation describes the patients selection, information and follow-up, the organization of the day care system, the computerized quality control and the medical outcome. Our experience is based on a 2-year period of day care surgery in a general community hospital. The results of 581 consecutively operated, not selected, patients are presented. Quality control was performed for all patients during their stay at the day care unit, and for 98.5% as follow-up control by the General Practitioners. The most frequent operations were: arthroscopies, meniscectomies, removals of implants after osteosynthesis, decompressions of peripheral nerves, large excisions of skin-tumors, bursectomies, reconstructions of torn ligaments, hernial repairs, strippings of varicose veins, hemorrhoidectomies and operations of the anal and genital region. We present the patients age, the type of anesthesia, the type of operation, eventual complications (in clinic, 24 hours after discharge and at the end of the treatment), the medical results as well as the costs of the after-treatment.

Aftercare↗
PubMed1994

Isolation and characterization of cDNAs encoding imidazoleglycerolphosphate dehydratase from Arabidopsis thaliana.

cDNA clones encoding imidazoleglycerolphosphate dehydratase (IGPD; EC 4.2.1.19) from Arabidopsis thaliana were isolated by complementation of a bacterial auxotroph. The predicted primary translation product shared significant identity with the corresponding sequences from bacteria and fungi. As in yeast, the plant enzyme is monofunctional, lacking the histidinol phosphatase activity present in the Escherichia coli protein. IGPD mRNA was present in major organs at all developmental stages assayed. The Arabidopsis genome appears to contain two genes encoding this enzyme, based on DNA gel blot and polymerase chain reaction analysis.

Amino Acid Sequence↗
PubMed1992

Overexpression of plant histidinol dehydrogenase using a baculovirus expression vector system.

A cDNA encoding cabbage histidinol dehydrogenase, including the chloroplast transit peptide sequence, was overexpressed using a baculovirus expression vector system. The maximum level of the expression of histidinol dehydrogenase was reached 5 days after infection of the insect cells. Two forms of recombinant histidinol dehydrogenase with molecular masses of 53 and 52 kDa, respectively, were obtained by a one-step purification from the cell homogenate. Compared with the 52-kDa form, the 53-kDa form contained 10 additional amino acids at the N-terminus derived from the transit peptide. By incubating the cell homogenate for 2 h at 30 degrees C, the 53-kDa form could be completely converted to the 52-kDa form. This conversion was blocked by leupeptin. Eighty percent of the converted 52-kDa form had Cys at position 31 at the N-terminal amino acid and the rest had Met 33. Kinetic properties of the recombinant enzyme were virtually identical to those of histidinol dehydrogenase isolated from cabbage plants. The overexpression of recombinant cabbage histidinol dehydrogenase in insect cells, the proteolytic processing of the preprotein next to the N-terminus (compared to the mature cabbage enzyme), and its easy purification allow the preparation of large amounts of the active enzyme for structural and functional studies.

Alcohol Oxidoreductases↗
PubMed1991

Structural and functional conservation of histidinol dehydrogenase between plants and microbes.

The partial amino acid sequence of histidinol dehydrogenase (L-histidinol:NAD+ oxidoreductase, EC 1.1.1.23) from cabbage was determined from peptide fragments of the purified protein. The relative positions of these peptides were deduced by aligning their sequences with the sequence of the HIS4C gene product of Saccharomyces cerevisiae. cDNA encoding histidinol dehydrogenase was then amplified from a library using a polymerase chain reaction primed with degenerate oligonucleotide pools of known position and orientation. By using this amplified fragment as a probe, an apparently full-length cDNA clone was isolated that is predicted to encode a proenzyme having a putative 31-amino acid chloroplast transit peptide and a mature molecular mass of 47.5 kDa. The predicted protein sequence was 51% identical to the yeast enzyme and 49% identical to the Escherichia coli enzyme. Expression of the cDNA clone in an E. coli his operon deletion strain rendered the mutant able to grow in the presence of histidinol.

Alcohol Oxidoreductases↗
PubMed1991

Purification and characterization of histidinol dehydrogenase from cabbage.

Histidinol dehydrogenase (EC 1.1.1.23) activity was determined in several plant species and in cultured plant cell lines. The enzyme was purified from cabbage (Brassica oleracea) to apparent homogeneity. To render complete purification, a new, specific histidinol-Sepharose 4B affinity chromatography was developed. The apparent molecular mass of the protein is 103 kDa. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the protein migrated as a single band with a molecular mass of 52 kDa, giving evidence for a dimeric quaternary structure. By isoelectric focusing, the enzyme was separated into six protein bands, five of which possessed the dehydrogenase activity when examined by an activity staining method. The Km values for L-histidinol and NAD+ were 15.5 and 42 microM, respectively. Enzyme activity was stimulated by addition of Mn2+, but was inhibited in the presence of Ba2+, Mg2+, Ni2+, Ca2+, Zn2+, or Cu2+. Histidinol dehydrogenase is the first histidine enzyme that has been purified to homogeneity and characterized from plants. This plant enzyme catalyzes the NAD-linked four-electron dehydrogenase reaction leading from histidinol to His. The results indicate a similar pathway of His in plants and show furthermore the last two reaction steps to be identical to those in microorganisms.

Alcohol Oxidoreductases↗
PubMed1988

Thermostable alanine racemase from Bacillus stearothermophilus: DNA and protein sequence determination and secondary structure prediction.

The nucleotide sequence of the alanine racemase (EC 5.1.1.1) gene from a thermophile, Bacillus stearothermophilus, was determined by the dideoxy chain termination method with universal and synthetic site-specific primers. The amino acid sequence of the enzyme predicted from the nucleotide sequence was confirmed by peptide sequence information derived from the N-terminal amino acid residues and several tryptic fragments. The alanine racemase gene consists of 1158 base pairs encoding a protein of 386 amino acid residues; the molecular weight of the apoenzyme is estimated as 43,341. The racemase gene of B. stearothermophilus has a closely similar size (1158 vs 1167 base pairs) to that of the gene of a mesophile, B. subtilis, but shows a higher preference for codons ending in G or C. A comparison of the amino acid sequence with those of Bacillus subtilis and Salmonella typhimurium dadB and alr enzymes revealed overall sequence homologies of 31-54%, including an identical octapeptide bearing the pyridoxal 5'-phosphate binding site. Although the residues common in the four racemases are not continuously arrayed, these constitute distinct domains and their hydropathy profiles are very similar. The secondary structure of B. stearothermophilus alanine racemase was predicted from the results obtained by theoretical analysis and circular dichroism measurement.

Alanine Racemase↗
PubMed1984

Partial purification and catalytic properties of a bifunctional enzyme in the biosynthetic pathway of beta-lactams in Cephalosporium acremonium.

The catalytic properties of the partially purified deacetoxycephalosporin C (DAOC)-synthetase and DAOC-hydroxylase from an industrial strain of Cephalosporium acremonium were studied. After mechanical breakage of the cells, purification was achieved by fractional (NH4)2SO4 precipitation, gel chromatography on Sephadex G-75, ion exchange chromatography on DEAE-Trisacryl M and two isoelectric focusing steps. The two enzyme activities could not be separated. Indirect evidence was obtained from SDS-polyacrylamide gel electrophoresis of the purest fractions obtained by isoelectric focusing that the two reactions are catalyzed by a single enzyme with a molecular weight of 33,000 +/- 2,000 and a pI of 4.6 +/- 0.1. Both reactions require alpha-ketoglutarate, FeSO4, ascorbate and O2, whereas additional ATP shows only a slight stimulation.

Acremonium↗
PubMed1984

[Ligament lesions of the knee--also a typical occupational injury].

Critical evaluation of 62 patients totalizing 63 operations with acute traumatic rupture of knee ligaments in a predominantly rural population. In 21 cases (30%) the lesions have been the result of typical work-injuries. A specific older group of patients was concerned (average age 50.2 years). 75% of these cases presented additional intrarticular lesions at operation. The postoperative evaluation 1-5 years later confirmed the heavy use of the knees in this rural population. We therefore strongly advocate an early primary repair of the ruptured ligaments of the knee especially in work-injuries and the use of a limited motion cast.

Accidents, Occupational↗
PubMed1980

[Hydrops of the gallbladder].

Of 739 cholecystectomies carried out from 1971 to 1978, 40 cases revealed intraoperatively a hydrops of the gallbladder. This hydrops was caused in all cases by a stone located in the gallbladder neck or the cystic duct. In 37 cases, the gallbladder contents were examined: clear "white bile" was present in 29 (78%); this was always very viscous. With one exception, all biles were found to be sterile. The pressure in the gallbladder averaged 61.5 cm saline, ranging from 15 to 115 cm. The osmolality of bile was on the average 295 mosmol/kg, thus being roughly isotonic with blood. In three cases, where chemical analysis of the bile was perfomed, bilirubin-, bile salts, cholesterol-, phospholipids, and protein-content were reduced to non-measurable amounts or to concentrations below 1 mg%. It is suggested that the mucosal inflammation following the obstruction to bile flow leads to disturbances in reabsorptive processes, secretion of mucous and a subsequent increase in intraluminal pressure.

Adult↗
PubMed1979

[Hypoproteinemia causing postoperative "interstitial" paralytic ileus].

On the basis of recent pathophysiological data and clinical observations in three patients, this paper draws attention to the commonly neglected importance of postoperative hypoproteinemia as the cause of an edema of the intestinal wall with a consequent "interstitial" paralytic ileus. The characteristic features of this syndrome are its onset between the third and the eighth postoperative day; the absence of other known causes of intestinal hypomotility; the benign, but protracted course without treatment; and the therapeutic success achieved by the correction of a hypoproteinemic fluid overload with concentrated albumin and a diuretic. In addition, parenteral hyperalimentation and Rheomacrodex-Sorbit may be indicated, but the hypoproteinemia should at any rate be corrected.

Aged↗