Biomedical subjects

A M Zeillemaker

Publications and source records attributed to A M Zeillemaker.

6 recordsLinked to original sources

PubMed1998

Piperacillin/tazobactam therapy for diabetic foot infection.

In this study, 29 patients were hospitalized with a diabetic foot infection and were treated with piperacillin/tazobactam. Of these 23 patients who were evaluated for efficacy of treatment, 22 patients improved or were clinically cured. In seven patients (30%), there was persistence of one of the baseline pathogens. Adverse events were reported in 15 patients (58%), three of which were serious. Piperacillin/tazobactam may be useful as monotherapy in diabetic foot infection giving an adequate clinical response and the level of side effects equivalent to those of other broad-spectrum antibiotics.

Adult↗

PubMed1996

Peritoneal interleukin-8 in acute appendicitis.

Interleukin-8 (IL-8) is a chemoattractant that is highly selective for neutrophils. This study was designed to investigate the presence of IL-8 in peritoneal fluid of patients with acute appendicitis. The clinical circumstances underlying the secretion of IL-8 by mesothelium and its mechanism of activation have not been defined. In an in vitro model for bacterial peritonitis the role of bacteria in activating human mesothelial cells to secrete IL-8 was studied. Cultured human mesothelium was incubated with various species of pathogenic bacteria, isolated from peritoneal exudate fluids of patients with appendicitis. The amount of IL-8 secreted by the cultured mesothelial cells was determined in an IL-8 ELISA, as IL-8 was present in the original peritoneal fluid of these patients. Peritoneal fluids from patients with a perforated appendix were found to contain a significantly higher concentration of IL-8 compared to peritoneal fluids from patients with nonperforating appendicitis (121.6 (57.8) ng/ml versus 0.2 (0.07) ng/ml, respectively; mean (SEM), P < or = 0.01). Species of Bacteroïdes and Fusobacterium necrophorum induced IL-8 secretion from cultured mesothelial monolayers to levels comparable to those found in peritoneal fluids in vivo. Heat-killed bacteria and bacterial supernatant were also able to stimulate mesothelium to secrete IL-8. The results suggest that in the early phase of bacterial peritonitis the influx of PMN is regulated by bacteria-induced IL-8 secretion by the mesothelium lining the peritoneal cavity.

Acute Disease↗

PubMed1996

Limited influence of the mesothelium on the influx of monocytes into the peritoneal cavity.

We have investigated the role of human mesothelium in an in vitro model of peritonitis on the monocyte adherence to and migration across monolayers of peritoneal mesothelial cells. Monocytes adhere avidly to non-activated mesothelial cell monolayers; however, migration in this situation was minimal. Prestimulation of the monolayers with II-1 beta did not alter these results. Anti-CD18 and anti-VLA-4 mAbs used in combination had an additive inhibitory effect on monocytes adherence to resting or IL-1 beta-pretreated mesothelial cells. MCP-1 and TGF-beta are secreted by mesothelial cells. Both have a modest role in mesothelium-induced monocyte chemotaxis: mAbs against these cytokines had an additive inhibitory effect on the chemotaxis induced by supernatant from 24-h prestimulated mesothelial cells. Our results indicate that the mesothelium itself has a limited role in the influx of monocytes into the peritoneal cavity during the onset of peritonitis.

Antibodies, Monoclonal↗

PubMed1996

Neutrophil adherence to and migration across monolayers of human peritoneal mesothelial cells. The role of mesothelium in the influx of neutrophils during peritonitis.

Increased adherence to and subsequent migration of leukocytes across cultured human peritoneal mesothelial cell monolayers takes place after pretreatment of the mesothelial cells with interleukin-1beta. The contribution of the leukocyte beta2 integrins (CD11/CD18) and the mesothelial adhesion protein intercellular adhesion molecule-1 (ICAM-1) and the role of the cytokines interleukin-8, platelet-activating factor (PAF), and transforming growth factor-beta (TGF-beta) were studied in a three-dimensional model system for neutrophil-mesothelial monolayer interaction. Polymorphonuclear leukocytes (PMNs) showed minimal adherence to and migration across unactivated mesothelial monolayers, despite an extensive amount of ICAM-1 on the mesothelial membrane. Pretreatment of the monolayers with rIL-1beta induced enhanced PMN adherence to the mesothelial monolayer together with a further increase in ICAM-1 expression on the mesothelial membrane. PMN migration was observed across rIL-1beta-activated mesothelial cell (MC) monolayers whenever cytokines secreted by the MCs were present during migration. Monoclonal antibody (mAb) R6.5 against ICAM-1 and mAb CLB-LFA1/1 against CD18 both reduced the migration of PMNs across mesothelial monolayers with a predominant inhibitory effect of CLB-LFA1/1, indicating a significant role of the beta(2) integrins of PMNs in this process. Interleukin-8 was the major cytokine synthesized by the MCs to stimulate the migration of PMNs; both PAF and TGF-beta had a more modest role in our system. Adherence of PMNs to MC monolayers was not dependent on these latter cytokines. Neuraminidase did not have any effect, indicating that selectins were not involved in the adherence process. rIL-1beta-pretreated MCs induced a rapid increase in intracellular Ca2+ in PMNs; actinomycin D blocked this effect and was also able to prevent adhesion of neutrophils to activated MC monolayers. Neutrophil migration across activated cultured MCs is thus a cascade of events in which the MCs are actively involved.

Calcium↗

PubMed1995

Polarized secretion of interleukin-8 by human mesothelial cells: a role in neutrophil migration.

We investigated the role of human mesothelium in an in vitro model of peritonitis with emphasis on the secretion of the neutrophil chemoattractant interleukin-8 (IL-8) and the migration of polymorphonuclear leucocytes (PMN) across monolayers of peritoneal mesothelial cells. PMN showed minimal migration across non-activated mesothelial monolayers (< 2%). However, migration was induced after mesothelial cell activation by IL-1 beta (24%) and this induced migration was significantly blocked by antibodies against IL-8 (63% inhibition; P < or = 0.01). IL-1 beta-activated mesothelial monolayers were shown to secrete IL-8 in a polarized way, which was preferentially oriented towards the apical side of the monolayer. Our results indicate that the influx of PMN into the peritoneal cavity is, at least in part, controlled by the mesothelial cell layer of the peritoneal membrane.

Cell Movement↗

PubMed1994

CA 125 secretion by peritoneal mesothelial cells.

AIMS: To investigate the secretion of the tumour marker CA 125 by cultured human mesothelial cells; to determine if secretion of CA 125 could be observed by activating the mesothelial monolayers with different cytokines. METHODS: Mesothelial cells were isolated from human omentum and cultured to confluent monolayers on perforated polycarbonate membranes (pore size 0.4 micron). The mesothelial monolayers were activated and the apical and basolateral secretion of CA 125 compared. To investigate the influence of cytokines, mesothelial cells were cultured and activated with recombinant interleukin-1 beta (rIL-1 beta), tumour necrosis factor-alpha (TNF-alpha) or lipopolysaccharide from Escherichia coli. The secretion of CA 125 was tested using a microparticle enzyme immunoassay. RESULTS: Mesothelial monolayers secreted CA 125 in a polarised manner with preference for the apical side. Apical polarisation occurred irrespective of the side of the inducing stimulus (p < or = 0.05). Non-activated cultured mesothelial monolayers secreted significant quantities of CA 125, indicating constitutive production of this protein. However, CA 125 production was significantly enhanced if mesothelial cells were incubated with rIL-1 beta (p < or = 0.05), TNF-alpha (p < or = 0.05), and E coli LPS (p < or = 0.01). CONCLUSIONS: Human mesothelial monolayers secrete CA 125 preferentially from their apical surfaces. The secretion of CA 125 can be enhanced by the inflammatory cytokines Il-1 beta, TNF-alpha, and by E coli LPS.

Antigens, Tumor-Associated, Carbohydrate↗