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Biomedical subjects

F Fiedler

Publications and source records attributed to F Fiedler.

At least 73 records · Page 4Linked to original sources
PubMed1994

Identification of the Staphylococcus sciuri species group with EcoRI fragments containing rRNA sequences and description of Staphylococcus vitulus sp. nov.

Strains of a new species, Staphylococcus vitulus, were isolated from food and a variety of mammals. This species was recognized on the basis of the results of an analysis of genomic EcoRI fragments containing portions of the rRNA operons. The patterns of hybridized fragments obtained from strains belonging to the new taxon were sorted into a distinguishable cluster and were distinct from the Staphylococcus lentus and Staphylococcus sciuri patterns. The results of DNA-DNA hybridization reactions demonstrated that strains in this cluster were more closely related to S. lentus and S. sciuri than to other Staphylococcus species and yet were significantly different. While these strains had some of the phenotypic characteristics of the S. sciuri species group, the newly recognized taxon could be distinguished by its very small colonies on P agar, absence of alkaline phosphatase activity, and lack of acid production from L-arabinose, maltose, N-acetylglucosamine, D-mannose, and raffinose. The type strain of the new species is strain DD 756 (= ATCC 51145).

Animals↗
PubMed1994

Production of Bacteriolytic Enzymes by Streptomyces globisporus Regulated by Exogenous Bacterial Cell Walls.

Mutanolysin biosynthesis and pigment production in Streptomyces globisporus ATCC 21553 were stimulated by adding bacterial cell walls to the medium. The increased bacteriolytic activity in the supernatant correlated with an increased de novo synthesis of mutanolysin and was between 4- and 20-fold higher than in cultures grown without bacterial cell walls. The increase in mutanolysin synthesis was brought about by enhanced transcription of the mutanolysin gene. The stimulation was only observed in medium which contained dextrin or starch as the carbon source. Glucose abolished the stimulation and also inhibited the low constitutive synthesis of mutanolysin. The induction of lytic activity was observed to require minimally 0.4 mg of bacterial cell walls per ml, whereas 0.6 mg of bacterial cell walls per ml yielded maximal lytic activity. Further supplements of bacterial cell walls did not result in enhanced lytic activity. The stimulation could be achieved independently of the phase of growth of the Streptomyces strain. Cultures grown in the presence of bacterial cell walls exhibited a higher growth yield. However, the accelerated growth was not the reason for the increased amount of mutanolysin produced. The growth of cultures with peptidoglycan monomers added to the medium instead of cell walls was similarly increased, but an effect on the biosynthesis of mutanolysin was not observed. All bacterial cell walls tested were capable of eliciting the stimulation of lytic activity, including cell walls of archaea, which contained pseudomurein.

Journal Article↗
PubMed1994

Formation of pi, tau-dimethylhistidine on alkylation of trypsin with active-site-directed sulfonic acid methyl esters.

The possibility of synthesizing stable alkyl analogues of acyl trypsins by introducing the alkyl residue by means of active-site-directed sulfonic acid esters was studied. Nine amidino- or guanidino-substituted sulfonic acids of different geometries and their methyl esters were prepared. The time-dependent inhibition of bovine trypsin by these esters, indicating modification at the active site of the enzyme, was followed. With the exception of p-guanidinobenzenesulfonic acid methyl ester, all the esters acted as irreversible inhibitors. The site of methylation, Ser-195 or His-57 (chymotrypsinogen numbering), was determine by analyzing for O-methylserine and methylhistidines. With four of the esters indications of a possible formation of, at most, 0.1 residue of O-methylserine per inactivated trypsin molecule were obtained. tau-Methylhistidine (but no pi-methylhistidine) was, however, always observed as the main product of the modification reaction. A further product, hitherto not yet described in active site methylations of serine proteinases, was pi, tau-dimethylhistidine (1,3-dimethylhistidine). The failure of an attempted synthesis of the N-acetyl-ethanolamine ester of p-toluene-sulfonic acid reported in the literature is shown to be due to the high instability of this ester.

Amino Acids↗
PubMed1993

A novel type of meso-diaminopimelic acid-based peptidoglycan and novel poly(erythritol phosphate) teichoic acids in cell walls of two coryneform isolates from the surface flora of French cooked cheeses.

The primary structure of the peptidoglycan and the teichoic acids of two coryneform isolates from the surface flora of French cooked cheeses, CNRZ 925 and CNRZ 926, have been determined. In the peptidoglycan, meso-diaminopimelic acid was localized in position three of the peptide subunit. It contained an D-glutamyl-D-aspartyl interpeptide bridge, connecting meso-diaminopimelic acid and D-alanine residues of adjacent peptide subunits. The alpha-carboxyl group of D-glutamic acid in position two of peptide subunits was substituted with glycine amide. The teichoic acid pattern and composition differed between the strains: both contained an erythritol teichoic acid and strain CNRZ 925 also contained an N-acetylglucosaminylphosphate polymer. The erythritol teichoic acids differed in terms of the quality and quantity of substituents, but they both had N,N'-diacetyl-2,3-diamino-2,3-dideoxyglucuronic acid in common.

Actinomycetales↗
PubMed1993

Development and application of a urodilatin (CDD/ANP-95-126)-specific radioimmunoassay.

Urodilatin, a renal natriuretic peptide that is an analogue to circulating atrial natriuretic peptide [alpha-ANP(99-126)], is measurable with a highly specific and sensitive radioimmunoassay. While most ANP antibodies cannot distinguish between urodilatin and other ANP analogues, the polyclonal urodilatin antibody specifically measures human urodilatin without any cross-reactivity to other ANP analogues. Urodilatin is not detected in blood from healthy volunteers nor from cardiac patients. Urinary urodilatin accounts for only a part of total urinary ANP immunoreactivity. Urodilatin excretion closely parallels sodium excretion in response to an acute volume load while changes in urinary immunoreactive ANP excretion do not reflect this renal response. We conclude that specific urodilatin assays are required to explore further the physiological role of the renal natriuretic peptide.

Amino Acid Sequence↗
PubMed1993

Cell-surface location of Listeria-specific protein p60--detection of Listeria cells by indirect immunofluorescence.

A specific polyclonal antiserum was prepared against a gel-purified 60 kDa extracellular protein of Listeria monocytogenes ATCC 19111 corresponding to protein p60 previously detected in culture broths of L. monocytogenes strains Mackaness and EGD [Kuhn, M. & Goebel, W. (1989), Infection and Immunity 57, 55-61]. Indirect immunogold labelling combined with transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the location and distribution of p60 on the bacterial cell surface. In bacteria grown to the early stationary phase about 25% of the extracellular protein was estimated to be associated with the cell surface. The anti-p60 antiserum proved to be Listeria-specific. In an indirect immunofluorescence test the antiserum reacted with Listeria strains representing all species and different serotypes, except L. seeligeri, L. welshimeri, L. grayi and L. murrayi. No immunological cross-reactions were observed with 27 strains of bacteria from 16 other genera. The value of the anti-p60 antiserum in developing a diagnostic assay for Listeria cells in environmental samples and foods is discussed.

Antibodies, Bacterial↗
PubMed1993

[Passive and continuous temporomandibular movement--functional treatment after surgery of the temporomandibular joint (TMJ)].

Limited opening of the mouth after surgery of the TMA is often treated by various technical means that are often not appropriate for this function. More specifically, many devices only perform extension to ensure normal opening of the mouth. Until now we have been using the Toronto Medical automated mobilization splint in 21 patients. Passive and continuous extension of the masticatory muscles using this device is a very useful method to achieve normal opening of the mouth in patients suffering from fractures and abscesses. Although this cannot be achieved in patients with tumors and ankylosis, the distance between incisors can still be increased to four times its original value.

Abscess↗
PubMed1992

The cAMP-binding ectoprotein from Saccharomyces cerevisiae is membrane-anchored by glycosyl-phosphatidylinositol.

Saccharomyces cerevisiae contains an amphiphilic cAMP-binding glycoprotein at the outer face of the plasma membrane (M(r) = 54,000). It is converted to a hydrophilic form by treatment with glycosyl-phosphatidylinositol-specific phospholipases C and D (GPI-PLC/D), suggesting membrane anchorage by a covalently bound glycolipid. Determination of the constituents of the purified anchor by gas-liquid chromatography and amino acid analysis reveals the presence of glycerol, myo-inositol, glucosamine, galactose, mannose, ethanolamine, and asparagine (as the carboxyl-terminal amino acid of the Pronase-digested protein to which the anchor is attached). Complementary results are obtained by metabolic labeling, indicating that fatty acids and phosphorus are additional anchor constituents. The phosphorus is resistant to alkaline phosphatase, whereas approximately half is lost from the protein after treatment with GPI-PLD or nitrous acid, and all is removed by aqueous HF indicating the presence of two phosphodiester bonds. Inhibition of N-glycosylation by tunicamycin or removal of protein-bound glycan chains by N-glycanase or Pronase does not abolish radiolabeling of the anchor structure by any of the above compounds. Analysis of the products obtained after sequential enzymic and chemical degradation of the anchor agrees with the arrangement of constituents in GPIs from higher eucaryotes. Evidence for anchorage of the yeast cAMP-binding protein by a GPI anchor is strengthened additionally by the reactivity of the GPI-PLC-cleaved anchor with antibodies directed against the cross-reacting determinant of trypanosomal variant surface glycoproteins.

Amidohydrolases↗
PubMed1992

Kinetics of bond cleavages at kallidin release by tissue kallikrein: cleavage of two peptide bonds in a single enzyme-substrate complex?

The kinetics of the release of kallidin, L- and KL-chains from bovine L-kininogen by porcine tissue kallikrein were followed and individual kinetic constants for cleavage of the Met-360 and the Arg-370 bond determined. The results suggest that both these bonds in L-kininogen r are hydrolyzed "simultaneously" without appearance of a free singly-nicked intermediate. Kallidin release in the human analogous system is also compatible with such a mechanism.

Animals↗
PubMed1992

Contribution of tumor necrosis factor to host defense against staphylococci in a guinea pig model of foreign body infections.

The contribution of the cytokine tumor necrosis factor (cachectin; TNF) to host defenses against staphylococcal foreign body infections was studied in vivo. In tissue cages subcutaneously implanted into guinea pigs, progressive infection was initiated by a very low inoculum (100 cfu) of Staphylococcus aureus with a success rate of 100%, as is frequently encountered in related clinical situations. Locally injected autologous bacterial components derived from the cell wall of S. aureus, in particular peptidoglycan, were very active in raising TNF levels in tissue cage fluid and in preventing the development of infection by the 100% infective dose of the test strain. Furthermore, injection of murine recombinant TNF into tissue cages could substitute for the bacterial components in preventing experimental infection by S. aureus. The protective effect of TNF-eliciting bacterial components could be neutralized by anti-TNF antibodies. A local increase in TNF levels might improve host defenses against staphylococcal foreign body infections.

Animals↗
PubMed1991

Metabolic and hormonal studies of type 1 (insulin-dependent) diabetic patients after successful pancreas and kidney transplantation.

Long-term normalization of glucose metabolism is necessary to prevent or ameliorate diabetic complications. Although pancreatic grafting is able to restore normal blood glucose and glycated haemoglobin, the degree of normalization of the deranged diabetic metabolism after pancreas transplantation is still questionable. Consequently glucose, insulin, C-peptide, glucagon, and pancreatic polypeptide responses to oral glucose and i.v. arginine were measured in 36 Type 1 (insulin-dependent) diabetic recipients of pancreas and kidney allografts and compared to ten healthy control subjects. Despite normal HbA1 (7.2 +/- 0.2%; normal less than 8%) glucose disposal was normal only in 44% and impaired in 56% of the graft recipients. Normalization of glucose tolerance was achieved at the expense of hyperinsulinaemia in 52% of the subjects. C-peptide and glucagon were normal, while pancreatic polypeptide was significantly higher in the graft recipients. Intravenous glucose tolerance (n = 21) was normal in 67% and borderline in 23%. Biphasic insulin release was seen in patients with normal glucose tolerance. Glucose tolerance did not deteriorate up to 7 years post-transplant. In addition, stress hormone release (cortisol, growth hormone, prolactin, glucagon, catecholamines) to insulin-induced hypoglycaemia was examined in 20 graft recipients and compared to eight healthy subjects. Reduced blood glucose decline indicates insulin resistance, but glucose recovery was normal, despite markedly reduced catecholamine and glucagon release. These data demonstrate the effectiveness of pancreatic grafting in normalizing glucose metabolism, although hyperinsulinaemia and deranged counterregulatory hormone response are observed frequently.

Adult↗
PubMed1991

Urodilatin, a kidney-derived natriuretic factor, is excreted with a circadian rhythm and is stimulated by saline infusion in man.

Urodilatin is a recently described, presumably kidney-derived member of the atrial natriuretic peptide family. The first data on a physiological role for urodilatin in the regulation of sodium homeostasis in humans is presented in this work. Urinary urodilatin excretion during a 9-day study in healthy volunteers paralleled the circadian rhythm in urinary sodium excretion. Furthermore, urodilatin and sodium excretion were slightly increased during the first 3 h after an acute isotonic saline infusion and about three-fold elevated during 14 h postinfusion; both parameters remained closely correlated up to 28 h postinfusion. These data suggest that urodilatin is involved in the circadian regulation of sodium excretion and is a physiological regulator of long-term sodium excretion after an acute saline infusion.

Adult↗
PubMed1991

[Peripheral oxygen saturation during dental surgery with and without premedication].

83 adults undergoing dental surgical procedures in local anesthesia were monitored continuously with a pulse oximeter for hypoxemia. 30 patients received as premedication either a combination of a neuroleptic drug and an opiate or a benzodiazepine. There was a drop in the oxygen saturation in 80% of the patients with premedication but only in 66% of the patients without. There were statistical highly significant more periods of hypoxemia in patients with premedication compared to the others. (1548 periods versus 659 periods p less than 0.001). The kind of premedication/sedation does not influence the number of hypoxic episodes. We conclude that especially patients with premedication should only be treated by surgeons with sufficient clinical experience in coping with emergency situations.

Anesthesia, Dental↗
PubMed1990

Occurrence and structure of lipoteichoic acids in the genus Staphylococcus.

Lipoteichoic acids were isolated from eleven species of the genus Staphylococcus using phenol-water partition and hydrophobic chromatography on octyl-Sepharose CL-4B. The lipoteichoic acids purified could be visualized by SDS-PAGE. They were shown to be composed of a hydrophilic poly(glycerophosphate) chain covalently linked to gentiobiosyldiacylglycerol, the common lipid anchor of these molecules. Glycerophosphate units of the hydrophilic chain were found to be partly substituted with ester-linked D-alanine, except in the case of S. cohnii. The lipoteichoic acids isolated from S. cohnii, S. hominis, S. saprophyticus and S. simulans contain alpha(1-2)-linked N-acetylglucosamine as an additional substituent of the poly(glycerophosphate) backbone.

Chromatography, Gas↗
PubMed1990

Evidence that urodilatin, rather than ANP, regulates renal sodium excretion.

Urodilatin, a closely related member of the atrial peptide family, was discovered recently in human urine. Urodilatin (ANP 95-126) is believed to be produced within the kidney and is natriuretic; evidence indicates that most of the ANP-like immunoreactivity in the kidney elutes with urodilatin rather than with ANP. Moreover, urodilatin is little affected by renal enzymes that inactivate atriopeptin. To determine the relative importance of urodilatin versus ANP in the regulation of renal sodium excretion, we studied intact and cardiac-denervated conscious dogs under three experimental conditions: (1) spontaneous sodium excretion, (2) intravenous infusion of saline, and (3) left atrial distension. Urodilatin was measured in urine with a newly developed radioimmunoassay that selectively measures urodilatin without any cross-reactivity with alpha-human atrial natriuretic peptide (alpha-hANP); alpha-hANP was measured in plasma by radio-immunoassay because it is rapidly inactivated in the kidney by enzymatic activity. In each group of experiments, sodium excretion correlated better with urodilatin than it did with circulating alpha-hANP. The correlation coefficient (r value) between urodilatin excretion and renal sodium excretion exceeded 0.8 in 13 of 18 experiments and was below 0.6 in only 2 experiments. On the other hand, the correlation between circulating atriopeptin and sodium excretion exceeded 0.8 in only 3 of 18 experiments and was below 0.6 in 10 experiments. A negative correlation between plasma atriopeptin and renal sodium excretion was observed during left atrial distension in the cardiac-denervated dogs. These results and other considerations suggest that urodilatin, rather than atriopeptin, is the member of the ANP family that is primarily involved in the regulation of renal sodium excretion.

Animals↗
PubMed1990

Effect of intraduodenal bile and Na- taurodeoxycholate on exocrine pancreatic secretion and on plasma levels of secretin, pancreatic polypeptide, and gastrin in man.

The effect of intraduodenally administered cattle bile (CB) and Na-taurodeoxycholate (TDC) on basal pancreatic secretion and plasma levels of secretin, pancreatic polypeptide (PP), and gastrin were investigated on two separate days in 10 fasting volunteers. Doses of 2-6 g CB and 200-600 mg TDC were given intraduodenally at 65-min intervals. Volume, bicarbonate, lipase, trypsin, amylase, and bilirubin were measured in 10-min fractions of duodenal juice, and GI peptides determined by radioimmunoassay. CB and TDC enhanced significantly and dose-dependently volume, bicarbonate and enzyme secretion, and plasma secretin and PP levels. In contrast, plasma gastrin showed only a marginal increase. We conclude that the hydrokinetic effect of intraduodenal CB and TDC is at least partially mediated by secretin. Gastrin could be ruled out as a mediator of the ecbolic effect, whereas other GI peptides, primarily CCK, and/or neural mechanisms must be considered possible mediators. Both pathways may also play a role in the PP release observed.

Adult↗
PubMed1988

Biochemistry of the cell surface of Listeria strains: a locating general view.

The cell surfaces of Listeria strains are composed of various compounds. These include peptidoglycan, teichoic acids and lipoteichoic acids. The structural features of these polymers are described and a macromolecular model of the organization of the cell wall of a Listeria cell is given. The occurrence of further components at the cell surface and biological aspects are briefly discussed.

Bacterial Outer Membrane Proteins↗