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Biomedical subjects

C Jensen

Publications and source records attributed to C Jensen.

At least 127 records · Page 7Linked to original sources
PubMed1984

Bacterial histamine release by immunological and non-immunological lectin-mediated reactions.

The mechanisms of bacteria-induced histamine release were examined in vitro in human leukocytes and rat mast cells. Three types of bacterial responders were found. In persons with IgE-bearing basophilocytes bacterial histamine release could be triggered by two different mechanisms, an IgE-dependent mechanism where removal of IgE abolished the release and a non-immunological mechanism where this was not the case. In responders with no IgE-bearing cells bacterial histamine release was caused by a non-immunological mechanism. The non-immunological mechanism was further substantiated by release in isolated mast cells from germ-free rats. These experiments suggest a direct interaction between bacteria and target cell, and experiments with multi-washed bacteria and bacteria cell wall preparations indicate the possibility of the bacteria wall interacting with the target cell. It is probable that the non-immunological mechanism depends on lectin-mediated reactions, since bacteria-induced histamine release was inhibited by lectin-binding sugars as is release caused by plant lectins.

Basophils↗
PubMed1984

Complexity of lectin-mediated reactions in bacteria-induced histamine release.

We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations.

Adult↗
PubMed1984

Staphylococcus aureus peptidoglycan induces histamine release from basophil human leukocytes in vitro.

Whole killed cells, cell walls, and peptidoglycans of Staphylococcus aureus were found to release histamine from human leukocytes and isolated rat mast cells in vitro. The histamine-releasing capability increased in the order of whole bacteria, cell walls, and peptidoglycans. Peptidoglycan was found to release histamine by a nonimmunological mechanism, as demonstrated by release in cells deprived of surface immunoglobulins, whereas whole bacteria and cell walls seemed to operate both by immunological and nonimmunological mechanisms. Histamine release was not a specific property of S. aureus; a wide range of whole bacterial species had this activity. We suggest that peptidoglycan may be a common factor responsible for histamine release by different bacteria.

Basophils↗
PubMed1984

Treatment of acute maxillary sinusitis. Erythromycin base and phenoxymethyl-penicillin (penicillin V).

One hundred patients with acute maxillary sinusitis have been studied. The diagnosis was made clinically and confirmed radiologically, using a roentgenological 6-point score for mucous membrane thickening and secretion. Fifty patients in each group were treated with either erythromycin base or phenoxymethyl-penicillin (penicillin V). The roentgenological state of each sinus was classified on the 1st, 5th, 10th, and 15th day, giving an objective evaluation of the treatment effect. There was no significant difference between the two treatment modes as to therapeutic outcome, and the results are compared with those of a larger material of 1220 patients with acute maxillary sinusitis studied in the same way at Lundby Hospital since 1970 (25 different treatment modes).

Acute Disease↗
PubMed1983

Intrinsic asthma and bacterial histamine release via lectin effect.

Bacteria-induced histamine release from basophil leukocytes was observed in vitro in both children with intrinsic asthma (IA) as well as in normal individuals. In vivo the release is suggested to take place only in the lung of IA patients, where a defective pulmonary barrier would permit the bacteria to enter, but not in healthy individuals. The study indicates that two different mechanisms of bacterial histamine release might exist, an IgE-mediated reaction and a non-immunological mechanism consisting of a direct interaction with the basophil cell surface. The non-allergic mechanism might depend on a lectin effect where bacterial surface lectins interact with the basophil cell surface leading to release of histamine. Inhibition studies with carbohydrates suggest a multi-lectin reaction in the bacterial histamine release involving several types of lectins on the bacterial membrane reacting with different carbohydrate moieties on the cell surface of basophil leukocytes.

Asthma↗
PubMed1983

Inhibitory effect of calcium antagonists on histamine release from human leukocytes. In vivo and in vitro experiments.

A study was made of the influence of calcium antagonists on human basophil histamine release induced in vitro by specific antigen, anti-IgE or the calcium ionophore A23187. Both verapamil, nifedipine, and nimodipine were found to inhibit the release, and a similar effect was also observed after peroral administration of verapamil and nifedipine. The inhibitory effect of the drugs on histamine release seems to depend on interaction with calcium at different sites. The anti-allergic effect might explain the improvement found with calcium antagonists in exercise-induced asthma.

Antibodies, Anti-Idiotypic↗
PubMed1983

Nutrient and mineral retention and vitamin D absorption in low-birth-weight infants: effect of medium-chain triglycerides.

A randomized prospective study of the effect of medium-chain triglycerides (MCT) upon the absorption and retention of major minerals and nutrients, as well as upon 25-hydroxy vitamin D levels, was performed in low-birth-weight infants. Ten infants received a high-calcium and vitamin D-containing formula, which contained 50% of its fat as MCT, while ten other infants received a similar formula in which all the fat was in long-chain triglycerides. There was a five-day delay in reaching full oral feeding volumes, and therefore there was a delay in the onset of the balance study in the MCT group, primarily due to gastrointestinal symptoms. There was a significant improvement in the percent of fat absorption (P less than .05) with MCT, but no difference in the percent of absorption or retention of calcium, phosphorus, sodium, or nitrogen. 25-Hydroxy vitamin D levels decreased in both groups after full oral feeding volumes had been established, but all values were within normal ranges. At the high intake levels of calcium and vitamin D given to the infants, MCT did not increase major mineral or nutrient absorption.

Calcium, Dietary↗
PubMed1983

The role of contact thermography in the diagnosis of deep venous thrombosis.

Contact thermography, a non-invasive inexpensive method of investigation for the diagnosis of deep venous thrombosis in the lower limb, was compared with conventional ascending phlebography in 69 patients. The results showed a diagnostic sensitivity of 97% and a diagnostic specificity of 50% giving an overall agreement of 73% between the methods. The low diagnostic specificity of thermography was to be expected, since any inflammatory reaction, whatever the cause, will give a rise in the skin-temperature. The high sensitivity shows that thermography is useful as a screening method. In the present material thermography could have prevented 25 per cent of the phlebographies.

Adult↗
PubMed1982

Acute maxillary sinusitis--a comparison between 27 different treatment modes.

When comparing the outcome of different treatment modes for acute maxillary sinusitis, the roentgenological examination can be recommended for the objective evaluation as a complement to the clinical examination. Using the occipito-mental projection and an additional occipito-mental side view, the diagnosis can be established in a cheap and simple way, and the treatment effect can be followed during the course of treatment in the form of radiological sinus changes. The treatment outcome of 27 different treatment modes in 1320 cases of acute maxillary sinusitis (2039 maxillary sinuses) was compared. There was little difference between the treatment groups as to therapeutic effect, whether using antral drainage alone, antibiotics alone or the combination of both. Factors other than treatment outcome must be important for the consideration of treatment choice, e.g. pharmacokinetics, administration, dosage, treatment cost, number and type of side effects, etc.

Anti-Bacterial Agents↗
PubMed1981

Purification and characterization of the membrane adenosine triphosphatase complex from the wild-type and N,N'-dicyclohexylcarbodiimide-resistant strains of Streptococcus faecalis.

We have purified the F1-F0 adenosine triphosphatase complex from wild-type Streptococcus faecalis ATCC 9790 and an N,N'-dicyclohexylcarbodiimide (DCCD)-resistant mutant strain, SF-dcc-8. For preliminary purification of the complex, reconstituted F1-F0, prepared from isolated F1 adenosine triphosphatase and depleted membranes, was extracted with sodium deoxycholate and fractionated by salt precipitation. By means of two-dimensional gel electrophoresis, the F1-F0 complex was purified as a single, catalytically active band in the first dimension and then resolved into constituent subunits under denaturing conditions in the second dimension. The electrophoretic purification of F1-F0 removed a delta-less form of F1 as well as other impurities, including lipoteichoic acid. Both the DCCD-sensitive and the DCCD-resistant F1-F0 adenosine triphosphatase appeared to consist of eight proteins, five of which corresponded to the F1 subunits alpha, beta,, gamma, delta, and epsilon. The F0 sector proteins, designated M27, M15, and M6, had Mr values of 27,000, 15,000, and 6,000, respectively. There appear to be multiple copies of M6 in the complex. [14C]DCCD reacted specifically and covalently with M6 in the wild-type F1-F0 but failed to label the M6 protein in the complex from the DCCD-resistant strain. It is suggested that DCCD resistance in the SF-dcc-8 mutant may be due to a modification of the M6 protein which hinders access of DCCD to the reactive site.

Adenosine Triphosphatases↗
PubMed1981

Spatially distinct allodeterminants of the H-2Kk molecule as detected by monoclonal anti-H-2 antibodies.

In an attempt to delineate spatial relationships between various allodeterminants of cell surface MHC antigens, competitive binding studies were performed using 4 different monoclonal antibodies, each of which reacted with the H-2Kk antigen but with different serologic specificities. Competition was studied by examining the effect of unlabeled antibodies on the binding of each 125I-labeled antibody to spleen cells of the H-2a haplotype. Mutual inhibition was observed between 2 of the antibodies, and a 3rd antibody of lower affinity was inhibited by the first 2 antibodies but did not itself inhibit the binding of these antibodies. The 4th antibody did not block the binding of the other 3 labeled antibodies, and binding of this 4th labeled antibody was only partially inhibitable by the other 3 antibodies. These results indicate the presence of at least 2 spatially distinct allodeterminants on H-2Kk molecules expressed on the cell surface.

Animals↗