Biomedical subjects

J Glette

Publications and source records attributed to J Glette.

25 records · Page 2Linked to original sources

PubMed1984

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. Irradiation of the polymorphonuclear leukocytes for 20 min in the presence of doxycycline (10 micrograms/ml) before phagocytosis completely abolished the rise in oxygen consumption initiated by zymosan. Demethylchlortetracycline and light exposure also caused a marked reduction of polymorphonuclear leukocyte oxygen consumption, whereas oxytetracycline, lymecycline, chlortetracycline, and minocycline had only a slight or no photosensitizing effect. The photodamage induced by doxycycline and demethylchlortetracycline was inhibited by azide and enhanced in deuterium oxide. This was in accordance with singlet oxygen-mediated damage.

Humans↗

PubMed1983

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. Bactericidal capacity and chemiluminescence were measured by standard methods. The red-to-green fluorescence ratio of acridine orange-stained PMNLs (R/G) was measured by FCM. Degradation of bacteria was monitored by the reduction in FITC and ethidiumbromide fluorescence of bacteria liberated from the phagocytes. Bacterial FITC fluorescence was pH dependent. Nf:N was 0.5 to 0.7. Using a standard curve for the interrelationship between bacterial fluorescence and pH, phagosomal pH was 5.0-5.5. Phagocytes, kept at 4 degrees C for 24 h had Nf:N approximately 1, did not degrade bacteria, but killed them and emitted chemiluminescence. NH4Cl increased phagocyte fluorescence by 27% and decreased R/G by 50%. Cyanide and azide did not affect Nf:N. Nf:N of phagocytes from a patient with chronic granulomatous disease was 32% below, and R/G was 32% higher than the controls. Acidification of the phagosomes seems to be related to discharge of PMNL granule contents and independent of the respiratory burst.

Acridine Orange↗

PubMed1983

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. The impairment of Tm was due to an inhibiting factor as well as lack of a stimulating plasma factor. Migration of granulocytes to skin chambers was decreased in patients with IgG myelomatosis. Chemiluminescence production during phagocytosis of opsonized zymosan was decreased. Compared to control sera, the opsonic activity of patient sera was strongly decreased. The impaired granulocyte functions in patients with malignant monoclonal gammopathy may contribute to the enhanced susceptibility to infections in these patients.

Aged↗

PubMed1982

Stimulation of the hexose monophosphate shunt activity in human polymorphonuclear leukocytes.

The glucose metabolism in human polymorphonuclear (PMN) leukocytes was stimulated by latex particles, zymosan particles, gamma-G globulin and formylmet-leu-phe (FMLP) peptide. Maximum stimulation occurred when zymosan particles in amounts above 0.25 mg/ml per 4 X 10(6) leukocytes were used. Latex particles, gamma-G globulin and FMLP stimulated the glucose oxydation less than zymosan particles. The glucose oxydation increase in proportion to the amount of latex particles and gamma-G globulin in the measured range, while the dose response curve using FMLP shows maximum activity at a consentration of the peptide of 5 X 10(-5)M per 4 X 10(6) leukocytes. It is likely that FMLP and gamma-G globulin act on the glucose metabolism via cell surface receptors. The synthetic polystyrene particles (latex) do not occupy these receptors, but stimulate the hexose monophosphate (HMP) shunt activity of the PMN via intracellular mechanisms. Opsonized zymosan particles seem to act on the leukocyte glucose metabolism via cell surface receptors as well as via intracellular mechanisms.

Glucose↗

PubMed1982

Factors influencing human polymorphonuclear leukocyte chemiluminescence.

Divalent cations (Mg2+, Ca2+) regenerated chemiluminescence (CL) of zymosan-stimulated human polymorphonuclear leukocytes (PMNs) abolished by 0.1 mM EGTA. Phenol red, erythrocytes and free haemoglobin reduced CL. To obtain maximal CL response, the reaction mixture should contain small amounts of protein and glucose. High protein concentrations reduced CL. The test had a pH optimum of 7.1. With respect to stability, however, the most favourable pH was 7.4. The CL response was highly temperature-dependent, and expressed as the initial rate constant of the CL time curve it increased linearly with increasing temperatures from 20 to 37 degrees C. Several factors influence the CL response by human PMNs and test procedures should be standardized.

Blood Platelets↗

PubMed1982

Polymorphonuclear leukocyte function in bacterial and viral infections.

Chemiluminescence (CL) production by polymorphonuclear leukocytes (PMNLs) was examined in 63 patients with bacterial infections and 63 healthy controls. The production was significantly higher in the patients (mean +/- standard error = 134.5 +/- 5.0 X 10(3) cpm) than in the controls (118.9 +/- 2.5 X 10(3) cpm; p less than 0.05). In 38 patients CL values were within the normal range and in 19 patients above. CL production below that of any control occurred in 6 patients: 3 (of 4) with staphylococcal endocarditis, 2 (of 4) with pneumococcal meningitis and 1 with salmonella septicaemia and osteomyelitis. PMNL hexose monophosphate shunt activity as measured by glucose metabolism correlated with CL production. Patients with low CL production more often had large numbers of juvenile and immature myeloid cells in the peripheral blood than patients with normal or high CL values. 3/6 patients with low CL values died, 2/38 with normal and 0/19 with high values. Directed and spontaneous PMNL migration was examined in 39 of the 63 patients with bacterial infections. 13 patients had PMNLs with higher directed and 16 with higher spontaneous migration capacity than their corresponding controls. The remaining patients had PMNLs with lower migration capacity. 2 of the 39 patients died. Each had PMNLs with low migration capacity. CL production by PMNLs was examined in 16 patients with viral infections and 16 healthy controls. The production was significantly lower in the patients (mean +/- standard error = 105.5 +/- 6.6 X 10(3) cpm) than in the controls (129.1 +/- 5.3 X 10(3) cpm; p less than 0.01). 15 patients had lower values than their corresponding controls. The PMNL migration capacity was also lower in the patients. These findings indicate that the majority of patients with bacterial infections have PMNLs with normal or increased function. However, some patients have reduced PMNL function and this reduction may contribute to a fatal outcome of the disease. Patients with viral infections usually have reduced PMNL function.

Adolescent↗

PubMed1981

Porphyrin-induced photodamage to isolated human neutrophils.

Human neutrophils were irradiated with light at 340-380 nm in the presence of low concentrations of protoporphyrin or uroporphyrin. At increasing light doses or increasing concentrations of protoporphyrin, the neutrophils rapidly lost the ability of locomotion. Also, neutrophil chemiluminescence and hexose-monophosphate shunt activity rapidly declined. An early event was leakage of endogenous K(+) followed by lactate dehydrogenase and at a later stage leakage of particle-bound acid phosphatase. A number of cellular enzymes were inactivated, the susceptibility to inactivation decreased in the order: succinate dehydrogenase greater than lactate dehydrogenase greater than glutamate dehydrogenase greater than acid phosphatase. Uroporphyrin had no effect on neutrophil functions, leakage of K(+), or cellular enzymes. The results suggest that photodamage to the plasma membrane and the mitochondria are earlier events than photodamage to lysosomes.

Humans↗