The effect of hyperoxygenation and reduced flow in fresh water and subsequent infectious pancreatic necrosis virus challenge in sea water, on the intestinal barrier integrity in Atlantic salmon, Salmo salar L.

In high intensive fish production systems, hyperoxygenation and reduced flow are often used to save water and increase the holding capacity. This commonly used husbandry practice has been shown to be stressful to fish and increase mortality after infectious pancreatic necrosis virus (IPNV) challenge, but the cause and effect relationship is not known. Salmonids are particularly sensitive to stress during smoltification and the first weeks after seawater (SW) transfer.

The involvement of Aeromonas salmonicida virulence factors in bacterial translocation across the rainbow trout, Oncorhynchus mykiss (Walbaum), intestine.

The pathogenic bacterium Aeromonas salmonicida is the causative agent of furunculosis, a lethal disease in salmonids. The mode of lateral transmission has not been conclusively defined, but A. salmonicida is able to translocate across the intestinal epithelium of salmonids, making the intestinal route a probable candidate.

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.

Damaging effect of the fish pathogen Aeromonas salmonicida ssp. salmonicida on intestinal enterocytes of Atlantic salmon (Salmo salar L.).

In fish, bacterial pathogens can enter the host by one or more of three different routes: (a) skin, (b) gills and (c) gastrointestinal tract. Bacteria can cross the gastrointestinal lining in three different ways. In undamaged tissue, bacteria can translocate by transcellular or paracellular routes.

Dietary vitamin C, immunity and disease resistance in Atlantic salmon (Salmo salar).

Presmolt Atlantic salmon were fed a fish meal based experimental diet supplemented with graded levels of ascorbate-2-monophosphate (AP), equivalent to 40, 400, 2000 and 4000 mg ascorbic acid (AA)/kg for 6 months prior to a bacterial challenge experiment. The liver AA concentration reflected the dietary intake of AP, but not linearly. Growth, hematology and acid phosphatase activity in zymosan stimulated macrophages were not affected by dietary AP.

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.

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.

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.

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).

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.

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.

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.

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.

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%).

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.

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.

Effect of tetracyclines and UV light on oxygen consumption by human leukocytes.

When polymorphonuclear leukocytes were stimulated with zymosan, a sharp rise in oxygen consumption was observed. In the presence of doxycycline, we observed a further increase in oxygen consumption when the phagocytosing cells were exposed to UV light. When the light was turned off, oxygen consumption of the cells almost ceased, indicating photodamage to polymorphonuclear leukocytes during irradiation.

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.

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.

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.

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.

Simultaneous measurement of phagocytosis and phagosomal pH by flow cytometry: role of polymorphonuclear neutrophilic leukocyte granules in phagosome acidification.

Human polymorphonuclear neutrophilic leukocytes (PMNLs) phagocytosed fluorescein-isothiocyanate (FITC)-labelled Staphylococcus aureus. Free bacteria, phagocytes, and nonphagocytes were discriminated and quantified by flow cytometry (FCM). The relative fluorescence of phagocyte-associated and free bacteria (Nf:N) was calculated by dividing the mean phagocyte fluorescence by that of the free bacteria and the number of phagocytosed bacteria.

Granulocyte function in malignant monoclonal gammopathy.

Granulocyte function was studied in 22 patients with untreated myelomatosis or macroglobulinaemia. Granulocyte adhesiveness (GA) and migration in capillary tubes (Tm) were, except for light chain disease, significantly decreased in patients of all gammopathy classes especially IgG myelomatosis. A plasma factor inhibited GA.