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Biomedical subjects

J Glette

Publications and source records attributed to J Glette.

At least 19 recordsLinked to original sources
PubMed2006

Translocation of viable Aeromonas salmonicida across the intestine of rainbow trout, Oncorhynchus mykiss (Walbaum).

The pathogenic bacterium Aeromonas salmonicida is the causative agent of the destructive disease furunculosis in salmonids. Horizontal transmission in salmonids has been suggested to occur via the skin, gills and/or intestine. Previous reports are contradictory regarding the role of the intestine as a route of infection. The present study therefore investigates the possibility of bacterial translocation across intestinal epithelia using Ussing chamber technology, in vitro. Intestinal segments were exposed for 90 min to fluorescein isothiocyanate-labelled pathogenic A. salmonicida. Sampling from the serosal side of the Ussing chambers showed that bacteria were able to translocate across the intestinal epithelium in both the proximal and distal regions. Plating and subsequent colony counting showed that the bacteria were viable after translocation. During the 90 min exposure to A. salmonicida, the intestinal segments maintained high viability as measured by electrical parameters. The distal region responded to bacterial exposure by increasing the electrical resistance, indicating an increased mucus secretion. This study thus demonstrates translocation of live A. salmonicida through the intestinal epithelium of rainbow trout, suggesting that the intestine is a possible route of infection in salmonids.

Aeromonas salmonicida↗
PubMed1992

Cloning and sequence analysis of two isotypic IgM heavy chain genes from Atlantic salmon, Salmo salar L.

A leukocyte cDNA library from Atlantic salmon, based on oligo-dT priming, was constructed in lambda-gt10. Immunoglobulin heavy chain (IgH) cDNA were isolated from the library using a specific probe generated by polymerase chain reaction (PCR) between two conserved areas within the variable region (second and fourth frame region). Two cDNA clones encoding the entire constant region of membrane-bound IgH, and one cDNA encoding the entire constant region of secretory IgH were sequenced, revealing messages from two isotypic IgM genes. Both genes were shown to be present in haploid embryos and have been isolated from a genomic library, the exons and deduced amino acid sequences of which are presented here (salmon CHA and CHB). The splicing of transcripts encoding the membrane-bound IgH excises the whole fourth exon as in other teleosts. The nucleotide and amino acid identity between salmon CHA and CHB are 98.2%, and 96.2%, respectively. Two subfractions of IgM from Atlantic salmon separated by ion chromatography can be explained by a net exchange of basic residues in salmon CHB compared to CHA. The finding of two closely related salmon CH genes is in accordance with the quasi-tetraploid state of the Atlantic salmon genome.

Amino Acid Sequence↗
PubMed1989

Effect of hyperbaric oxygen treatment on immunological parameters in multiple sclerosis.

Hyperbaric oxygen (HBO) treatment has been reported to cause amelioration of clinical symptoms in patients with multiple sclerosis (MS). We have treated 10 MS patients with hyperbaric oxygen (100% O2 at 2 atmospheres absolute for 90 min daily for a total of 20 exposures), and performed immunological studies on peripheral blood and cerebrospinal fluid (CSF). After treatment there was a significant increase in total and helper T lymphocyte counts in peripheral blood, as well as an increase in both E, Fc gamma and C3b receptor-bearing lymphocytes. The responses to the mitogens PHA, con A and PWM were unchanged. Granulocytes showed an increased proportion of Fc gamma receptor and C3b receptor positive cells after treatment. The O2 consumption of granulocytes also increased, but phagocytosis, as measured by chemiluminescence, was unchanged. Serum IgA levels were slightly increased, while IgG and IgM concentrations remained unchanged after treatment. Cerebrospinal fluid cell counts, protein and IgG concentrations, as well as IgG indexes remained unchanged.

Adult↗
PubMed1987

Lucigenin-dependent chemiluminescence in mononuclear phagocytes. Role of superoxide anion.

A method for the measurement of reactive oxygen species generated by activated mononuclear phagocytes by use of lucigenin-dependent chemiluminescence was developed. Opsonized zymosan was used as a stimulant to evaluate the chemiluminescence response of monocytes. A cell-free system in which superoxide anion and hydrogen peroxide were produced by the xanthine-xanthine oxidase reaction was used to examine the role of these radical species in the excitation of lucigenin, and to standardize the chemiluminescence method. It was found that the light emission in lucigenin-dependent chemiluminescence was evoked by the superoxide anion, but other radicals may also be active.

Acridines↗
PubMed1987

In vitro evaluation of the activity of Entamoeba histolytica studies on motility.

The tube migration test for leukocyte function studies has been modified to test the motility of Entamoeba histolytica. The test was more sensitive to the effect of antiamebic drugs than was a test for phagocytic activity. A 50% reduction in amebic motility was seen instantly after exposure to metronidazole (40 mg/l). A similar reduction of phagocytosis at the same concentration of the drug was seen only after two hours' preexposure. The extent of amebic migration in the test tube is dependent on factors such as concentration of parasites, temperature and incubation time. The tube migration test is cheap and simple and could be a valuable supplement to existing screening methods for potential antiamebic drugs.

Animals↗
PubMed1986

Phototoxicity of tetracyclines as related to singlet oxygen production and uptake by polymorphonuclear leukocytes.

The photo-induced singlet oxygen production of six tetracyclines was measured as tryptophan degradation. Demethylchlortetracycline was the most efficient singlet oxygen producer followed by doxycycline. The least efficient producer was minocycline. Doxycycline, however, was the most potent inducer of photodamage to polymorphonuclear leukocytes (PMNLs) followed by demethylchlortetracycline. Accordingly, the singlet oxygen production during irradiation did not correlate with the induction of photodamage to the PMNLs. However, the uptake of doxycycline by the cells was 3 times higher than that of demethylchlortetracycline, and the tetracycline-induced photodamage to the PMNLs correlated with the product of singlet oxygen production during irradiation and the drug uptake by the cells.

Free Radicals↗
PubMed1986

Factors important for the measurement of chemiluminescence production by polymorphonuclear leukocytes.

Chemiluminescence (CL) production by phagocytosing polymorphonuclear leukocytes (PMNLs) was measured by an automatic photoluminometer with built-in mixing and temperature controls. Agitation of the vials with PMNLs and opsonized zymosan particles influenced both the lag time and the CL production. Maximal production was obtained by continuous mixing of the samples, the reaction peak occurring within 6 min. Increasing the temperature from 20 to 40 degrees C also increased the CL production, and in further experiments 37 degrees C was used. Aggregation of the PMNLs was avoided by washing the cells in PBS containing gelatin 1 g/l. Glucose, Ca2+ and Mg2+ in the final reaction mixture were necessary for maximal CL responses. The measurements of CL per s up to 4 min, the peak CL value, or the integral below the CL curve up to 6 min were all linearly proportional to the number of PMNLs in the reaction mixture. Since the lag time and the time before reaching peak CL may vary, the integral below the curve up to 6 min was chosen as the mode of CL measurement. On repeated measurements the coefficient of variation was 6.3%. The mean CL integral value for PMNLs from 14 healthy individuals was 205 +/- 19 mVs, indicating a good reproducibility of the standardized assay.

ABO Blood-Group System↗
PubMed1986

Influence of tetracyclines and light on the release of lysozyme from human granulocytes and monocytes.

Doxycycline inhibited the release of lysozyme from human granulocytes and monocytes exposed to non-opsonized zymosan particles. This effect was more marked for granulocytes than for monocytes. Oxytetracycline, however, did not influence the release. The difference between the drugs can be explained by differences in their lipid solubilities. The divalent cation chelator, EDTA, also reduced the release of lysozyme from leukocytes exposed to non-opsonized zymosan. Accordingly, the selective release of lysozyme from human leukocytes is divalent cation dependent. The inhibition of release by doxycycline is most likely also due to binding of these ions. When the cells were exposed to UVA light in the presence of doxycycline, the inhibition of lysozyme release was potentiated. Using irradiated cells, maximal inhibition was obtained at 20 micrograms doxycycline/ml. However, it is not clear whether these results have clinical relevance.

Doxycycline↗
PubMed1986

Granulocyte function in patients with multiple sclerosis.

Peripheral blood granulocytes and sera from patients with relapsing/remittent (group I) and chronic progressive (group II) multiple sclerosis (MS) did not differ from control cells and sera with regard to the proportion of cells bearing receptors for Fc gamma and C3b; random or directed (chemotactic) motility of granulocytes; activation as measured by chemiluminescence; opsonic activity of sera. The results of this study suggest that granulocyte function in MS is normal.

Cell Movement↗
PubMed1985

Influence of fever temperatures and of some cytoactive drugs on in vitro lysozyme release from monocytes and granulocytes.

The selective in vitro release of lysozyme from human monocytes and granulocytes was not greatly influenced by temperatures above 37 degrees C and up to 40 degrees C. The release was markedly inhibited by preincubation with phenylbutazone, oxyphenylbutazone, colchicine and vincristine. A water-soluble hydrocortisone complex also inhibited lysozyme release, but at high concentrations, lysis of the cells occurred. Although methotrexate had a weak inhibiting effect, no appreciable influence on release was observed with cyclophosphamide or cytarabine. Thus, release of lysozyme from blood leukocytes is likely to be dependent on cellular functions involving the stability of both microtubules and membranes.

Body Temperature↗
PubMed1985

The influence of antimicrobial agents on macrophage-associated Staphylococcus aureus.

Macrophages obtained by culturing human blood monocytes were incubated with Staphylococcus aureus for phagocytosis to occur and exposed to gentamicin, rifampin, clindamycin or trimethoprim/sulphamethoxazole. The macrophage-associated bacteria were protected against gentamicin at low concentrations (1 mg/l) and trimethoprim/sulphamethoxazole. However, high concentrations of gentamicin and clindamycin reduced the number of bacteria, indicating that these drugs penetrated into human macrophages and killed phagocytosed bacteria. Rifampin, even at low concentrations (0.5 mg/l), caused a marked reduction in macrophage-associated bacteria, implying that the drug penetrated into the phagocytes and retained its effect in the cells most effectively.

Anti-Bacterial Agents↗
PubMed1985

In vivo and in vitro effects of doxycycline on leucocyte membrane receptors.

Tetracyclines, particularly doxycycline, have adverse effects on granulocyte function in vitro. We have examined the effects of doxycycline on membrane receptors for IgG (Fc gamma-R) and C3b (C3b-R) on granulocytes and lymphocytes, as well as on the sheep erythrocyte receptor (E-R) on T lymphocytes. Acne patients given doxycycline orally had a lower percentage of Fc gamma-R positive granulocytes (57%) than before treatment (80%) or compared to healthy controls (81%). Following in vitro doxycycline incubation, normal granulocytes showed decreased levels of Fc gamma-R positive cells. This effect was counteracted by the addition of magnesium during incubation. The deleterious effect of doxycycline on granulocyte functions may be due to decreased levels of Fc gamma-R bearing granulocytes. Doxycycline in vivo or in vitro had no significant effect on the proportion of C3b-R bearing granulocytes or lymphocytes or the T lymphocyte percentage. After in vitro irradiation with light at 340-380 nm, however, both granulocytes and lymphocytes preincubated with doxycycline showed up to 50% decrease in Fc gamma-R bearing cells, while control cells without doxycycline were unaffected.

Acne Vulgaris↗
PubMed1984

In vitro release of lysozyme from monocytes and granulocytes.

When exposed to zymosan or latex particles or heat-inactivated staphylococci, freshly prepared human blood monocytes and granulocytes rapidly released a large fraction of their lysozyme content. Within 24 hours the total lysozyme activity in the monocyte suspensions tripled, while it doubled in the granulocyte suspensions, indicating synthesis of the enzyme following release. The monocytes in particular seemed to release and synthesize lysozyme without any other stimulus than contact with lymphocytes and the tube walls. Potassium caseinate in solution did not influence the lysozyme release. Myeloperoxidase and beta-glucuronidase, which in the granulocytes are kept in lysosomal fractions separate from most of the lysozyme, were neither released nor synthesized to a significant degree. Moreover, the minute amount of lactate dehydrogenase released indicated that the lysozyme release was not the result of cell lysis. Accordingly, the monocytes, which are not already stimulated by adherence to nonphagocytosable surfaces, are capable of selective enzyme release similar to that of the granulocytes.

Glucuronidase↗
PubMed1984

Mechanisms of decreased leucocyte adhesiveness and migration in plasma from patients with IgG myelomatosis.

The adhesiveness of leucocytes in human plasma was decreased by the addition of IgG M-protein, commercial IgG, F(ab)2-fragments, or bovine serum albumin (BSA). Leucocyte migration was inhibited by IgG M-protein and commercial IgG, but not by reduced and alkylated IgG, F(ab)2-fragments or BSA. Guinea pig serum (GPS) strongly enhanced leucocyte migration in Hanks' balanced salt solution. This effect was abolished by hydrazine treatment or heating, and reduced, but not abolished, by zymosan treatment. C4-deficient guinea pig serum (C4-def-GPS), but not zymosan treated C4-def-GPS stimulated migration. In IgG myeloma sera migration was enhanced by the addition of C4-def-GPS and by untreated or heated, but not hydrazine treated GPS, and inhibited by zymosan treated GPS. IgG M-protein inhibits leucocyte adhesiveness and migration. Migration is specifically inhibited by the intact IgG, probably through complement activation with consumption of heat stable chemokinetic factor(s) and production of migration inhibitors.

Animals↗
PubMed1984

The influence of harvesting intervals on chemiluminescence and enzyme activities of rat peritoneal leukocytes.

Rat leukocytes were obtained from the peritoneal cavity by stimulation with potassium caseinate. The chemiluminescence response of the polymorphonuclear leukocytes exposed to opsonized zymosan was influenced by the interval between instillation of caseinate and harvesting of the cells. With intervals increasing from four to 72 hours, the maximum activity was reached after 24 hours. The myeloperoxidase activity of all the leukocytes together increased gradually up to 72 hours after instillation of caseinate. After exposure to zymosan particles, only a negligible fraction of this enzyme was released from the cells. On the other hand, the lysozyme activity was highest in cells harvested early, and a large fraction of this enzyme was also released from these cells. The findings emphasize the importance of standardized conditions for stimulation and harvesting of rat peritoneal leukocytes.

Animals↗
PubMed1984

Influence of tetracyclines on human polymorphonuclear leukocyte function.

Low concentrations of oxytetracycline, doxycycline, or minocycline (less than 10 micrograms/ml) did not influence in vitro polymorphonuclear leukocyte random migration, chemiluminescence, or glucose oxidation. At high concentrations of doxycycline or minocycline (greater than 10 micrograms/ml), chemiluminescence and glucose oxidation were impaired. High concentrations of doxycycline also reduced random migration. Oxytetracycline did not influence these functions in concentrations up to 100 micrograms/ml. The inhibiting effect of doxycycline and minocycline was abolished when 4 mM Mg2+ was added to the reaction mixture, and 4 mM Ca2+ partly restored minocycline-inhibited polymorphonuclear leukocyte functions. This indicates that the major effect of tetracyclines on in vitro polymorphonuclear leukocyte functions is mediated by their divalent cation chelating effect and that the results of in vitro experiments are highly dependent on the concentration of divalent cations in the reaction mixtures. The difference between the tetracyclines may be due to differences in lipid solubility, with solubility being highest for minocycline and lowest for oxytetracycline, or to different divalent cation chelating ability.

Cations↗