Myocardial disposition of [1-11C]palmitic acid, 2,2',3,3'-tetradeuteropalmitic acid and octanoic acid in the pig.
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Animals↗
Biomedical subjects
M Wikström
Publications and source records attributed to M Wikström.
Production and characterization of monoclonal antibodies to Vibrio cholerae soluble haemagglutinin.
Monoclonal antibodies (MAbs) against a protease of Vibrio cholerae, the soluble haemagglutinin (sHA), have been prepared and characterized with regard to their ability to inhibit different biological properties of sHA and to protect against experimental V. cholerae infection. Four fusion experiments yielded two specific immunoglobulin G1 MAbs that reacted with sHA produced by different V. cholerae O1 and non-O1 strains but that differed in their antigen-binding capacity. Both MAbs were capable of inhibiting the haemagglutinating and protease activities of sHA as well as its ability to nick the enterotoxin A subunit, but neither of them had any effect on the mucinase activity of sHA. One of the MAbs significantly inhibited experimental cholera infection induced by sHA-producing V. cholerae O1 in rabbit small intestine.
Animals↗
Cell respiration. Catalytic intermediates.
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Catalysis↗
Determination of urinary vanillylmandelic acid by direct injection and coupled-column chromatography with electrochemical detection.
An automated column-switching system for determination of vanillylmandelic acid in urine is described. The liquid chromatographic system was composed of two separation columns with different selectivity properties, an octadecyl column coated with tributyl phosphate as stationary liquid phase and a silica-based anion exchanger. Urine samples were injected directly onto the first column, where vanillylmandelic acid was separated from the main part of the sample matrix. The internal standard isovanillylmandelic acid was co-eluting with vanillylmandelic acid, and a fraction of the eluate containing both substances was switched to the second column, where separation was performed. To assess peak purity, detection was performed with dual working electrodes in parallel mode. A relative standard deviation of 3.5% was obtained for determination of human urine samples containing 3 microM vanillylmandelic acid, and less than 0.1 microM could be detected.
Chromatography, Liquid↗
Effect of root debridement on the elimination of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis from periodontal pockets.
The aims of this 6-month longitudinal study were: (1) to investigate to what extent root debridement of pockets in adult periodontitis will reduce the subgingival presence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and some other bacterial groups; (2) to relate the microbiological results following debridement to clinical measurements of healing. 16 patients and a total of 111 periodontally involved sites with probing depth greater than or equal to 6 mm served for the study. Duplicate subgingival microbial samples and duplicate clinical recordings were obtained 1 week apart at baseline and at 6 months following supra- and subgingival debridement. The results demonstrated reductions of the mean total viable counts and reductions of the mean counts of several of the cultured groups of micro-organisms coupled with significant improvements of mean clinical measurements. B. gingivalis was eliminated from a majority of infected subgingival sites. A. actinomycetemcomitans, on the other hand, still remained after therapy in a high proportion of sites initially infected with this microorganism. Subgingival persistence of A. actinomycetemcomitans appeared to be associated with a reduced healing response following debridement. Further studies are needed to clarify why A. actinomycetemcomitans is poorly eliminated following debridement. Also, the long-term clinical significance of the subgingival perseverance of A. actinomycetemcomitans needs to be elucidated.
Actinobacillus↗
On the inability of root debridement and periodontal surgery to eliminate Actinobacillus actinomycetemcomitans from periodontal pockets.
In a previous study, we observed that root debridement was inefficient in eliminating Actinobacillus actinomycetemcomitans from adult periodontitis lesions. The present report describes the effects on A. actinomycetemcomitans of subsequent treatments of 6 patients that had at least 2 separate sites still harboring A. actinomycetemcomitans 6 months following debridement. 1 site or more in each individual was treated with renewed root debridement and at least 1 other site was treated by surgical excision of the gingival tissue. The results indicated that retreatment with either repeated root debridement or with surgical excision of the gingival tissue was not more effective in eliminating A. actinomycetemcomitans than initial debridement. The possible reasons for this limited therapeutic effect on the subgingival presence of A. actinomycetemcomitans are discussed.
Actinobacillus↗
Reproducibility of microbiological samples from periodontal pockets.
Duplicate microbiological samples, were taken 1 week apart using the paper point technique from a total of 112 untreated periodontal pockets greater than 6 mm deep in 16 adult periodontal patients. Duplicate samples were also obtained from these sites 6 months following a therapy of oral hygiene instruction and supra- and subgingival debridement. The reproducibility of the total viable counts and the reproducibility of the proportions of various groups or species of microorganisms were studied from these duplicate samples. The results demonstrated an acceptable degree of reproducibility for the recovery of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis. For the total viable counts and for the other investigated bacterial groups, including Bacteroides intermedius, unacceptable levels of reproducibility were observed.
Actinobacillus↗
Biochemical and serological characterization of Bacteroides intermedius strains isolated from the deep periodontal pocket.
Fifty-one fluorescence-positive black-pigmented Bacteroides strains obtained from 51 patients with deep periodontal pockets (greater than 6 mm) were identified and characterized. Fifty of these strains were presumptively identified as Bacteroides intermedius according to the indole reaction. This was confirmed by further biochemical characterization. The 50 strains from diseased sites were then compared with 16 B. intermedius strains isolated from periodontally healthy individuals with no signs of destructive periodontal disease. Tests for antimicrobial susceptibility showed similar patterns for all 50 pocket-derived strains, except for one beta-lactamase-positive strain that was resistant to penicillin G and ampicillin. Forty-seven strains were tested for binding of three monoclonal antibodies defining three distinct serogroups of B. intermedius. Thirty-one strains belonged to serogroup I, three to serogroup II and thirteen to serogroup III. In comparison to the strains from the shallow periodontal pockets, serogroup I was significantly overrepresented in the patient group with periodontal disease. We conclude that saccharolytic black-pigmented Bacteroides species from deep periodontal pockets constituted, with very rare exceptions, a biochemically homogeneous but antigenically heterogeneous group of B. intermedius and that serogroup I is predominantly found in deep periodontal lesions.
Bacteroides↗
Decreased lactoferrin content in granulocytes from subjects with Actinobacillus actinomycetemcomitans associated periodontal diseases.
Fourteen subjects were examined for lactoferrin content in PMNs of venous blood. Eight of the subjects were diagnosed localized juvenile periodontitis (LJP) and four adult periodontitis (AP), all having subgingival occurrence of Actinobacillus actinomycetemcomitans (A.a.). Two subjects had healthy gingival conditions and no detectable A.a. Deficiency or low PMN lactoferrin amounts were found in six of the eight subjects with LJP and in two of the subjects with AP. The reduced lactoferrin content in the PMNs was suggested to be depending on a cytotoxic factor produced by A.a. adding to an intrinsic PMN defect.
Actinobacillus↗
Magnetic resonance imaging of acute myocardial infarction in pigs using Gd-DTPA.
Six pigs with coronary artery occlusion were investigated with MR imaging before and subsequently for about 2.5 hours at repeated intervals after the intravenous administration of Gd-DTPA (0.4 mmol/kg). The animals were sacrificed after a total occlusion time of 6 hours and the hearts were excised. The excised hearts were then reexamined in the MR equipment and stained with TTC (triphenyl tetrazolium) in order to define areas of infarction. Four control hearts with 6-hour-old infarctions were only imaged ex vivo without any previous administration of contrast media. In vivo, there was no clear demarcation of infarction with or without Gd-DTPA. Ex vivo, without any contrast media, the infarctions were poorly discriminated with a discretely increased signal intensity relative to normal myocardium in the T2 weighted images. Gd-DTPA was found to accumulate in the infarctions, which caused an elevated signal intensity most pronounced in the T1 weighted images. This considerably improved the delineation of the infarcted area.
Animals↗
Deletion of the gene for subunit III leads to defective assembly of bacterial cytochrome oxidase.
COIII is one of the major subunits in the mitochondrial and a bacterial cytochrome c oxidase, cytochrome aa3. It does not contain any of the enzyme's redox-active metal centres and can be removed from the enzyme without major changes in its established functions. We have deleted the COIII gene from Paracoccus denitrificans. The mutant still expresses spectroscopically detectable enzyme almost as the wild-type, but its cytochrome c oxidase activity is much lower. From 50 to 80% of cytochrome a is reduced and its absorption maximum is 2-3 nm blue-shifted. The EPR signal of ferric cytochrome a is heterogeneous indicating the presence of multiple cytochrome a species. Proteolysis of the membrane-bound oxidase shows new cleavage sites both in COI and COII. DEAE-chromatography of solubilized enzyme yields fractions that contain a COI + COII complex and in addition haem-binding, free COI as well as free COII. The mutant phenotype can be complemented by introducing the COIII gene back to cells in a plasmid vector. We conclude that cytochrome oxidase assembles inefficiently in the absence of COIII and that this subunit may facilitate a late step in the assembly. The different oxidase species in the mutant represent either accumulating intermediates of the assembly pathway or dissociation products of a labile COI + COII complex and its conformational variants.
Chromatography, DEAE-Cellulose↗
[Indications and guidelines for treatment of periodontal infections with antibiotics].
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Anti-Bacterial Agents↗
Cytochrome o (bo) is a proton pump in Paracoccus denitrificans and Escherichia coli.
Spheroplasts from aerobically grown wild-type Paracoccus denitrificans cells respire with succinate despite specific inhibition of the cytochrome bc1 complex by myxothiazol. Coupled to this activity, which involves only b-type cytochromes, there is translocation of 1.5-1.9 h+/e- across the cytoplasmic membrane. Similar H+ translocation ratios are observed during oxidation of ubiquinol in spheroplasts from aerobically grown mutants of Paracoccus lacking cytochrome c oxidase, or deficient in cytochrome c, as well as in a strain of E. coli from which cytochrome d was deleted. These observations show that the cytochrome o complex is a proton pump much like cytochrome aa3 to which it is structurally related.
Cytochrome b Group↗
Identification of the electron transfers in cytochrome oxidase that are coupled to proton-pumping.
Mitochondrial cytochrome oxidase is a functionally complex, membrane-bound respiratory enzyme which catalyses both the reduction of O2 to water and proton-pumping. During respiration, an exogenous donor, cytochrome c, donates four electrons to O2 bound at the bimetallic haem alpha 3 Fe-Cu centre within the enzyme. These four electron transfers are mediated by the enzyme's haem alpha and CuA redox centres and result in the translocation of four protons across the inner mitochondrial membrane. The molecular mechanism of proton translocation has not yet been delineated, however, and in the absence of direct experimental evidence all four electron transfers have been assumed to couple equally to proton-pumping. Here, I report the effects of proton-motive force and membrane potential on two equilibria involving intermediates of the bimetallic centre at different levels of O2 reduction. The results show that only two of the electron transfers, to the 'peroxy' and 'oxyferryl' intermediates of the bimetallic centre, are linked to proton translocation, a finding which strongly constrains candidate mechanisms for proton-pumping.
Adenosine Triphosphate↗
The plasma membrane potential of human neutrophils. Role of ion channels and the sodium/potassium pump.
Calcium-depleted human neutrophils are depolarised when suspended in calcium-free media containing sodium ions, and are repolarised by extracellular replenishment of Ca2+. The depolarisation is due to a high inward sodium current, which is blocked by calcium and by several other divalent cations, but not by barium. Addition of calcium results in a rise in the cytosolic concentration from approx. 20 nM to the resting level of approx. 130 nM. Calcium influx is strongly accelerated by a voltage-gated calcium channel. This channel might be responsible for the depolarising Na+ current in the absence of divalent cations. In the polarised state the neutrophil membrane has a high intrinsic permeability to K+, which may be low or absent in the depolarised state. Generation of membrane potential from the depolarised state is mainly due to the electrogenic sodium/potassium pump. However, the resting potential of about -75 mV is maintained primarily by the K+ conductance, and only to a small extent by the sodium/potassium pump.
Calcium↗
Galanin-, neuropeptide Y- and enkephalin-like immunoreactivities in catecholamine-storing paraganglia of the fetal guinea pig and newborn pig.
The occurrence and distribution of several neuropeptides and transmitter enzymes have been investigated by means of indirect immunofluorescence histochemistry in preaortal and carotid body-like paraganglia of the fetal guinea pig and the newborn pig. Preaortal paraganglia from the celiac and inferior mesenteric ganglion regions in fetal guinea pigs showed cell bodies immunoreactive (IR) for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), neuropeptide Y (NPY), galanin (GAL) and metenkephalin (ENK). Almost all cells were IR for TH and DBH, whereas NPY-like immunoreactivity (-LI), GAL-LI and ENK-LI occurred less frequently. Direct double-labeling revealed the coexistence of NPY/GAL, NPY/ENK and GAL/ENK in paraganglion cells from the celiac and inferior mesenteric region. Nerve fibers and terminals were IR for ENK; fibers IR for calcitonin-gene-related peptide (CGRP) were present in the inferior mesenteric ganglion region. Preaortal paraganglia cells from the newborn pig showed TH-LI, DBH-LI, GAL-LI and ENK-LI, the distribution pattern being similar to that seen in the guinea pig; however, NPY-LI was absent. Carotid-body-like paraganglia from the newborn pig showed cell bodies IR to TH, GAL and ENK. Few cells were seen with DBH-LI. A rich supply of nerve fibers with CGRP-LI was present; some fibers exhibited ENK-LI and CCK-LI. In the adjacent superior cervical ganglion, ganglion cell bodies showed immunoreactivity to TH, DBH and NPY. A small number of cells were positive for GAL, CGRP and vasoactive intestinal polypeptide (VIP). Physiological activation of the paraganglia, leading to release or increase in catecholamines, may also change the content of the neuropeptides present in the paraganglia.
Animals↗
Monomerization of cytochrome oxidase may be essential for the removal of subunit III.
1. Incubation of cytochrome oxidase, under conditions used as initial steps in treatment to remove subunit III, causes at least partial monomerization of the enzyme. 2. The extent of removal of subunit III by anion-exchange fast protein liquid chromatography (FPLC) is much increased if the enzyme is fully monomerized before it is applied to the column. 3. Subunit III is incompletely removed by chymotrypsin treatment. A digestion product of subunit III migrating in SDS-PAGE like subunit IV, is detected with specific antibodies. The amount of this product is reduced when monomerization is increased by raising the detergent/protein ratio. 4. The results suggest that monomerization facilitates removal of subunit III and exposes it to further chymotrypsin digestion. We propose that subunit III is at least in part located in the junction between the monomers in the cytochrome oxidase dimer.
Animals↗
Protonic sidedness of the binuclear iron-copper centre in cytochrome oxidase.
The oxidised (ferric-cupric) binuclear centre of cytochrome oxidase is converted into two other states, presumably ferrylcupric (F) and ferric-peroxy-cupric (P), by energy-dependent reversed electron transfer from the centre (and water) to cytochrome c [(1981) Proc. Natl. Acad. Sci. USA 78, 4051-4054; (1987) Chem. Scr. 27B, 53-58]. This sequence of events represents a partial reversal of the O2 reduction catalysed by the centre. Here it is shown that the strong pH-dependence of these reactions is exerted specifically from the matrix (M) side of the inner mitochondrial membrane. This proves unequivocally that the binuclear centre generates protonmotive force by means of its vectorial accessibility for electrons and protons.
Animals↗