Advanced oxidation protein products as a novel marker of oxidative stress in uremia

Evidence suggests an imbalance between antioxidant and oxidant-generating systems resulting in oxidative stress in uremic patients. As plasma proteins are critical targets for oxidants, we developed a novel spectrophotometric assay which allows to detect advanced oxidation protein products (AOPP) in uremic plasma. By size-exclusion chromatography AOPP are retrieved in two distinct peaks at 600 and below 80 kDa in uremic plasma, while no such peaks are found in control plasma. Further biochemical characterization revealed that AOPP are carried by oxidized plasma proteins, especially albumin and do not have oxidant properties. AOPP increased in a dose-dependent manner following in vitro exposure of plasma or purified human serum albumin (HSA) to hypochlorous acid. Advanced glycation end products of human serum albumin (AGE-HSA) also increased AOPP levels. In vivo, plasma level of AOPP was the highest in patients on hemodialysis, followed by those on peritoneal dialysis and by undialyzed patients with advanced chronic renal failure. AOPP levels correlated with plasma concentrations of dityrosine and AGE-pentosidine, as indices of oxidant-mediated protein damage, but not with thiobarbituric reactive substances as lipid peroxidation markers. A close correlation was also found between AOPP and neopterin levels, suggesting that AOPP could be part in the monocyte-mediated inflammatory disorders associated with uremia. In conclusion, we propose the measurement of AOPP as a reliable marker to estimate the degree of oxidant-mediated protein damage in uremic patients and to predict the potential efficacy of therapeutic strategies aimed at reducing such an oxidative stress.

Expression of functional HIV-1 integrase in the yeast Saccharomyces cerevisiae leads to the emergence of a lethal phenotype: potential use for inhibitor screening

The integrase of the human immunodeficiency virus type 1 (HIV-1) has been expressed in yeast in order to investigate its potential lethal effect mediated by DNA damage. To this end, we have constructed an expression plasmid containing the retroviral integrase gene under the control of the inducible promotor ADH2/GAPDH which is regulated by the glucose concentration of the medium. Haploid yeast strain W303-1A did not appear to be clearly sensitive to HIV-1 integrase expression. However, disruption of the RAD 52 gene, which is involved in the repair of double-strand DNA breaks, strongly increased the deleterious effects of the retroviral enzyme in this yeast strain. The diploid strain constructed with W303-1A and an isogenic strain of the opposite mating type also showed a strong sensitivity to the HIV-1 integrase. Under yeast culture conditions allowing moderate integrase synthesis, the deleterious effect was totally abolished by missense integrase mutations, which are known to abolish HIV-1 integrase activities in vitro. We conclude that the lethal phenotype due to HIV-1 integrase expression in yeast may be closely related to the HIV-1 integration reaction in infected human cells, and that yeast may be a useful tool to study the HIV-1 integration process and to screen drugs capable of inhibiting HIV-1 integration in vivo.

Role of endogenous cardiac glycosides in the spontaneously hypertensive rat--antagonism by active immunization

The effects of simultaneous active immunization against two cardiac glycoside drugs, digoxin and proscillaridin, have been examined in young spontaneously hypertensive and Wistar-Kyoto rats. Control animals were immunized with protein carrier only. Animals were studied from 5 weeks to 13 weeks of age. Effectiveness of immunization to produce antibody responses was assessed at the end of the study by estimating the titer of antibodies in plasma against both of the antigens. Robust antibody responses were obtained. Immunization had no effect on the normal growth of these animals. Further, immunization against cardiac glycosides did not change blood pressure in either strain of animals. Blood pressure in the SHR increased as anticipated as the weanling animals grew to maturity. These studies indicate that active immunization against cardiac glycosides does not alter blood pressure in the SHR in spite of strong evidence for increased levels of endogenous cardiac glycosides in this strain.

Glutathione antioxidant system as a marker of oxidative stress in chronic renal failure

A profound imbalance between oxidants and antioxidants has been suggested in uremic patients on maintenance hemodialysis. However, the respective influence of uremia and dialysis procedure has not been evaluated. Circulating levels of copper-zinc superoxide dismutase (CuZn SOD), glutathione peroxidase (GSH-Px), and reductase (GSSG-Rd), total GSH and GSSG were determined in a large cohort of 233 uremic patients including 185 undialyzed patients with mild to severe chronic renal failure, and 48 patients treated by peritoneal dialysis or hemodialysis. Compared to controls, erythrocyte GSH-Px and GSSG-Rd activities were significantly increased at the mild stage of chronic uremia (p < .001), whereas erythrocyte CuZn SOD activity was unchanged, total level of GSH and plasma GSH-Px activity were significantly decreased, and GSSG level and GSSG-Rd activity were unchanged. Positive Spearman rank correlations were observed between creatinine clearance and plasma levels of GSH-Px (r = .65, p < .001), selenium (r = .47, p < .001), and GSH (r = .41, p < .001). Alterations in antioxidant systems gradually increased with the degree of renal failure, further rose in patients on peritoneal dialysis and culminated in hemodialysis patients in whom an almost complete abolishment of GSH-Px activity was observed. In conclusion, such disturbances in antioxidant systems that occur from the early stage of chronic uremia and are exacerbated by dialysis provide additional evidence for a resulting oxidative stress that could contribute to the development of accelerated atherosclerosis and other long-term complications in uremic patients.

Neutrophil-derived long-lived oxidants in cystic fibrosis sputum

We evaluated long-lived oxidant potential in the sputum of patients with cystic fibrosis (CF) by quantitating the methionine-inhibitable, long-lived oxidant fraction of sputum, referred to as the chloramines. Taurine, the preferred amino acid substrate for chloramine formation, and myeloperoxidase (MPO), the chlorinated oxidant-generating enzyme, were also quantitated. As compared with the sputum of asthmatic subjects, the sputum of CF patients contained high concentrations of chloramines along with high levels of taurine and active MPO. A negative correlation between chloramine and taurine was found in the sputum of CF patients. No correlation was found between the density of Pseudomonas aeruginosa and the level of chloramines, taurine, or MPO. In contrast, respiratory parameters (%FEV or %FVC) and a nutritional index correlated positively with chloramine levels, whereas negative correlations were observed with taurine and MPO. In addition, the effect of antibiotic therapy, which significantly increased chloramine and decreased taurine levels, supported a beneficial effect of chloramines on overall clinical status. Our findings support a dual role of long-lived oxidants at the site of airway inflammation in CF, one component of which is their ability to mediate oxidative stress and the other a beneficial effect that may be partly explained by their inhibitory effect on antiprotease defense systems.

Circumscribed choroidal hemangioma

BACKGROUND

Circumscribed or solitary choroidal hemangioma is a relatively rare, benign vascular tumor. Because its appearance may mimic more serious intraocular lesions, eye care practitioners should be familiar with differential diagnosis and treatment options.

METHODS

A patient presented with an asymptomatic, elevated, red-orange lesion above the macula in the right eye and a history of longstanding unexplained visual acuity loss in the eye. Intraocular lesions such as amelanotic melanoma, metastatic tumor, choroidal osteoma, disciform scar, serous detachment, and central serous chorioretinopathy can appear similar to circumscribed choroidal hemangioma (CCH) on ophthalmoscopy, but may be differentially diagnosed with fluorescein angiography, ultrasonography, and periodic observation.

RESULTS

CCH requires various therapeutic options. Until the patient becomes symptomatic from visual loss secondary to serous macular detachment or subretinal neovascular membrane formation, no treatment is necessary. Laser photocoagulation is the preferred therapeutic intervention, and most patients will require a minimum of two sessions. A small percentage of individuals will progress to complete retinal detachment with profound visual loss regardless of therapy. Most CCHs remain stable in size and do not undergo malignant transformation.

CONCLUSIONS

CCHs may be overlooked because of their initial subtle clinical appearance with no associated cutaneous or systemic anomaly. Even though CCH is a benign tumor, it may mimic more serious intraocular lesions and require a combination of ancillary tests for proper diagnosis. Depending on visual symptoms or potential threat to vision, management options include periodic observation, laser photocoagulation, cryotherapy, microwave therapy, and possible enucleation. CCH has little or no growth potential, but visual prognosis remains guarded due to significant secondary retinal changes that can occur over the tumor's surface. CCH must be considered in the differential diagnosis of an elevated intraocular lesion.

[Dysregulation of the immune system in chronic uremic and hemodialysed patients]

Concomitant immune deficiency and activation of immuno-competent cells, together with a disequilibrium between inflammation-inducing cytokines and their specific natural inhibitors is the basis of our current understanding of immune system dysregulation in patients with chronic uraemia. These anomalies may even be accentuated by dialysis. Clinically, bacterial infections, viral hepatitis and amyloidosis all play important roles. Humoral factors include abnormal immunoglobulin response to specific antibodies and complement activation. The response of T lymphocytes, long sought as the origin of the immunodeficiency associated with chronic uraemia, is also significantly decreased in these patients. The decreased antibody responses to specific stimuli may be related to B cell dysfunction. Monocyte and polymorphonuclear cell reactions are also perturbed. A deficiency in natural killer cells is observed although the mechanisms involved and the consequences are still debated. The factors determining the anomalies leading to immune system dysregulation in chronic uraemia and dialysis and their relationship with the reduction in active nephron mass as well as their metabolic and/or endocrine consequences remain to be fully described. A better understanding of the mechanisms involved should lead to new strategies for immuno-intervention in patients with chronic renal failure and help in optimizing haemodialysis.

Balance between IL-1 beta, TNF-alpha, and their specific inhibitors in chronic renal failure and maintenance dialysis. Relationships with activation markers of T cells, B cells, and monocytes

Patients with end-stage renal disease present an immunodeficiency that paradoxically coexists with activation of most immunocompetent cells, and the roles of chronic uremia and maintenance dialysis are poorly understood. We determined circulating levels of IL-1 beta and IL-1Ra, TNF-alpha and its soluble receptors (TNF-sR55 and TNF-sR75), and activation markers of T cells (soluble CD25), B cells (soluble CD23), and monocytes (neopterin) in a large cohort of undialyzed patients at various stages of chronic renal failure and in dialyzed patients on maintenance hemodialysis or chronic peritoneal dialysis. The progression of uremia was associated with a gradual increase in soluble CD25, CD23, and especially neopterin levels. Although IL-1 beta could not be detected, IL-1Ra levels were significantly increased from the earliest stage of renal failure. Plasma levels of TNF-alpha, TNF-sR55, and TNF-sR75 progressed with the severity of renal failure and correlated with soluble CD25, CD23, and neopterin levels, whereas IL-1Ra levels correlated exclusively with TNF-sR55 levels. Compared with undialyzed patients, levels of IL-1 beta were higher in patients on maintenance hemodialysis, whereas those of IL-1Ra were lower and decreased further at the end of dialysis sessions. In contrast, both TNF-sR55 and TNF-sR75 levels were significantly higher than in undialyzed patients and increased further at the end of dialysis sessions in the absence of an increase of TNF-alpha. Such an imbalance between cytokines and their inhibitors may play a pivotal role in the multifaceted process of immune dysfunction.

Balance between IL-1 beta, TNF-alpha, and their specific inhibitors in chronic renal failure and maintenance dialysis. Relationships with activation markers of T cells, B cells, and monocytes

Patients with end-stage renal disease present an immunodeficiency that paradoxically coexists with activation of most immunocompetent cells, and the roles of chronic uremia and maintenance dialysis are poorly understood. We determined circulating levels of IL-1 beta and IL-1Ra, TNF-alpha and its soluble receptors (TNF-sR55 and TNF-sR75), and activation markers of T cells (soluble CD25), B cells (soluble CD23), and monocytes (neopterin) in a large cohort of undialyzed patients at various stages of chronic renal failure and in dialyzed patients on maintenance hemodialysis or chronic peritoneal dialysis. The progression of uremia was associated with a gradual increase in soluble CD25, CD23, and especially neopterin levels. Although IL-1 beta could not be detected, IL-1Ra levels were significantly increased from the earliest stage of renal failure. Plasma levels of TNF-alpha, TNF-sR55, and TNF-sR75 progressed with the severity of renal failure and correlated with soluble CD25, CD23, and neopterin levels, whereas IL-1Ra levels correlated exclusively with TNF-sR55 levels. Compared with undialyzed patients, levels of IL-1 beta were higher in patients on maintenance hemodialysis, whereas those of IL-1Ra were lower and decreased further at the end of dialysis sessions. In contrast, both TNF-sR55 and TNF-sR75 levels were significantly higher than in undialyzed patients and increased further at the end of dialysis sessions in the absence of an increase of TNF-alpha. Such an imbalance between cytokines and their inhibitors may play a pivotal role in the multifaceted process of immune dysfunction.

In vitro and in vivo activities of reduced-size antagonists of luteinizing hormone-releasing hormone

A novel series of octapeptide LHRH antagonists was designed on the basis of the structure of the (2-9) fragment of a LHRH agonist. By adopting a systematic SAR study, we were able to improve first the in vitro activity and then the in vivo LH suppression, raising them up to the range of the decapeptide antagonists NalGlu (51) and A-75998 (50), resulting in A-76154 (49). The octapeptide antagonist A-76154 is the most potent reduced-size LHRH antagonist reported. It suppresses LH in the castrated rat by over 80% for a period of 4 h following sc bolus administration of 30 micrograms/kg.

Soluble CD23 as an effector of immune dysregulation in chronic uremia and dialysis

Patients with chronic renal failure often present an immunodeficiency state paradoxically exacerbated by hemodialysis and associated with signs of T cell activation. The presence of circulating monokines suggests that monocytes are also activated. Whether or not this includes B cells is controversial, despite frequently abnormal antibody responses. We thus investigated whether the soluble low-affinity receptor for IgE (Fc epsilon RII/CD23), recently identified as a marker of B cell and monocyte activation and possibly involved in T cell activation, was modulated by chronic renal failure and hemodialysis. Relative to values in healthy individuals (N = 31), plasma concentrations of soluble CD23 were significantly elevated in non-dialyzed chronically uremic patients (N = 44), more elevated in patients on peritoneal dialysis (N = 24), and most elevated in those on regular hemodialysis (N = 132), stabilizing after about six months. Soluble CD23 levels were unmodified by the first dialysis session but rose markedly during regular dialysis with cellulose or polysulfone membranes, but not with polyacrilonitrile AN-69 membranes. Soluble CD23 levels correlated with levels of IgG, and those of tumor necrosis factor alpha and interleukin-6, suggesting that increased sCD23 levels reflect activation of B cells and monocytes, respectively. These findings reinforce the view of soluble CD23 as a multi-functional receptor/cytokine, and provide evidence that it might contribute to the immune dysregulation associated with chronic renal failure and exacerbated by hemodialysis.

Quality of care and outcomes of chronic mentally ill patients in hospitals and nursing homes

OBJECTIVE

Quality of care in three types of facilities in which chronic mentally ill patients reside was examined to determine how it was related to patient functioning and to determine how patients' dependency on others for self-care moderated relationships between quality of care and patient functioning.

METHODS

Discriminant function analyses and multiple regression analyses were used to examine 12-month follow-up data from a Department of Veterans Affairs (VA) study of 294 chronic mentally ill patients in 52 community nursing homes, nine VA nursing home care units, and 43 VA hospital psychiatric units.

RESULTS

The three types of facilities were best differentiated by staff and resident characteristics and facility policies. Residents of community nursing homes were more impaired, and staff were less well trained, than in the VA facilities. The community nursing homes had less restrictive policies. Patients who lived in facilities that gave them more control over their daily lives and that had larger proportions of high-functioning patients reported more life satisfaction and vigor. Patients in facilities with more social and recreational activities reported less life satisfaction. The extent to which facility features were beneficial or harmful was related to patients' self-care dependency. Supportive physical features and living-assistance services tended to aid impaired residents, whereas more experienced staff and policies that promoted control by residents tended to aid independent residents.

CONCLUSIONS

Program managers may need to tailor facility environments to patients' level of functioning to maximize beneficial effects.

Microtiter plate assay for phagocyte-derived taurine-chloramines

Despite their potential importance, the role of phagocyte-derived chloramines ("long-lived oxidants") has not yet been investigated in inflammatory or infectious diseases. We have developed a sensitive spectrophotometric microtiter plate assay for chloramines based on their capacity to oxidize potassium iodide (KI). Consistent levels of endogenous chloramines were detected in normal human polymorphonuclear neutrophil (PMN) supernatants after stimulation by phorbol myristate acetate (PMA) or opsonized zymosan. Exogenous taurine strongly enhanced chloramine secretion and was used to quantify the chlorinating potential of PMN. Taurine-chloramines were also detectable in monocyte supernatants, although in smaller amounts. The specificity of the KI assay was assessed both in terms of effect of compounds inhibiting (KBr) or interacting with (sodium azide and catalase) chloramine formation and by showing that PMN from patients with chronic granulomatous disease, due to a hereditary lack of oxidative response capacity, were unable to produce chloramines. Taurine-chloramine levels secreted by PMA (but not zymosan)-stimulated PMN were closely related to the cellular luminol-amplified chemiluminescence (CL) responses although the CL assay failed to detect chloramines in PMN supernatants. We consider that this KI assay should be of use in studying the role of long-lived phagocyte-derived oxidants in clinical medicine.

Induction of cytokines by dialysis membranes in normal whole blood: a new in vitro assay for evaluating membrane biocompatibility

We investigated the capacity of cellulose cuprophane (CUP) and synthetic polyacrylonitrile dialysis membranes to induce the production of interleukin 1 (IL-1), interleukin 6 (IL-6), and tumor necrosis factor alpha using an in vitro model in which normal whole blood is incubated directly with calibrated membrane fragments. We found that only CUP membranes significantly increased plasma levels of IL-1, IL-6, and tumor necrosis factor alpha. The participation of lipopolysaccharide was excluded, since its addition to whole blood incubated with CUP led to a synergistic enhancement of IL-1 production, while the addition of polymyxin B had no significant effect. Transfer experiments showed that CUP-pretreated plasma was able to induce cytokine production by autologous monocytes. Inactivation of complement components prior to pretreatment abolished this effect. The participation of complement activation was further revealed by a correlation between cytokine and C5a plasma levels. Lastly, incubation of isolated monocytes with CUP but not with polyacrylonitrile also induced cytokine production, although to a lesser degree. In conclusion, our simple in vitro model can be used to evaluate the biocompatibility of dialysis membranes directly by using whole blood with greater relevance to the in vivo situation than models based on isolated blood components.

Pholasin: a new chemiluminescent probe for the detection of chloramines derived from human phagocytes

We have previously reported that normal human polymorphonuclear neutrophils (PMN) release taurine-chloramine, a long-lived oxidant, in response to stimulation by phorbol myristate acetate (PMA) or opsonized zymosan in the presence of exogenous taurine. We now describe a new, simple, and highly sensitive method for the detection of chloramines, including taurine-chloramine, using the chemiluminescent probe Pholasin, the luciferin of the mollusc Pholas dactylus. Taurine-chloramine (N-chlorotaurine) detection was assessed with both a colorimetric method (based on the oxidation of potassium iodide) and with the Pholasin-dependent chemiluminescence (CL) method. The taurine-chloramine concentration in PMN supernatants determined using the potassium iodide (KI) method correlated closely with Pholasin-dependent CL. This CL was also assessed in nonoxidative conditions. No taurine-chloramine was detected in supernatants of lymphocytes and PMN from patients with an oxidative burst defect (chronic granulomatous disease, CGD) with the KI method, but Pholasin-dependent CL was consistently observed. The use of methionine, a specific chloramine scavenger in our incubation conditions, allowed us to define a methionine-inhibitable fraction of Pholasin-dependent CL (i.e., chloramine-induced CL).

Elevated circulating levels of interleukin-6 in patients with chronic renal failure

In a previous study, we demonstrated the presence of circulating interleukin-1 (IL-1) in long-term dialyzed patients and that of tumor necrosis factor alpha (TNF alpha) in both long-term and not yet dialyzed uremic patients. In the present study, we attempted to determine the respective influence of hemodialysis (HD) and uremia on the plasma level of interleukin-6 (IL-6), which shares several biological properties with IL-1 and TNF alpha, including the induction of the acute phase response of the inflammatory process. Forty-eight patients with end-stage renal failure, including 32 long-term HD patients and 16 chronic uremic patients undergoing their first dialysis session, were tested for plasma IL-6 using both biological and immunoreactive assays. Plasma IL-6 activity was significantly increased in patients with chronic renal failure (P less than 0.001) compared to its level in normal individuals. No difference was observed, however, between long-term and not yet dialyzed patients. In the patients with the most pronounced IL-6 activity, immunoreactive IL-6 levels between 60 and 150 pg/ml were detected. A monoclonal antibody (mAb) against human IL-6 inhibited the activity of plasma in the IL-6 bioassay, and a close correlation existed between the biological activity of IL-6 and its immunoreactive level. No change in plasma IL-6 was detected during the course of the first dialysis as well as subsequent sessions. Likewise, no influence of the nature (cellulosic or synthetic polyacrilonitrile) of the dialysis membrane equipping the dialyzer was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

A marked drop in the incidence of the null allele of the B gene of the fourth component of complement (C4B*Q0) in elderly subjects: C4B*Q0 as a probable negative selection factor for survival

The incidence of allotypes of the genes of the fourth component (C4) and factor B of the complement system was compared in 252 persons under 45 years of age ("young" group) with 482 people between 61 and 90 years of age ("old" group). One hundred people older than 90 years of age (nonagenarians) were also investigated. A striking difference was found between the "young" and "old" groups in the incidence (16.1% and 5.4%, respectively) of a silent gene of the C4B allele (C4B*Q0). This difference was even more marked among "young" and "old" men (17.6% vs 3.4%). The incidence of the C4B*Q0 allele in women dropped to the level of the men only in the nonagenarian group. The most probable explanation for this finding is that people carrying the C4B*Q0 allele die from as yet unidentified disease(s) in their middle-age. Therefore, male (and to a lesser extent female) carriers of this allele may have a considerably shorter life expectancy than individuals without a silent gene in the C4B locus.

Establishing the relationship between complement activation and stimulation of phagocyte oxidative metabolism in hemodialyzed patients: a randomized prospective study

The present prospective study was conducted in order to establish the relationship between complement activation and stimulation of phagocyte oxidative metabolism observed in long-term hemodialysis (HD) patients during the early phase of dialysis with cellulosic membranes. Two groups of 10 randomized (HD) patients treated with cellulosic (Cuprophan, CUP) or synthetic polyacrilonitrile (PAN AN-69) membranes were studied. Leukocyte counts, C3a antigen plasma concentration and whole blood basal and stimulated chemiluminescence (CL) production were determined in blood samples drawn from the fistula before dialysis (T0) and from both the afferent and efferent lines of the dialyser at 15 min (T15) and at the end (Tend) of the dialysis session. This study confirms that, coincident with the nadir of leukopenia observed at T15, dialysis with CUP but not PAN membranes induces a marked rise in C3a antigen levels and profound alterations in whole blood CL production consisting of a dramatic increase in basal CL and a significant loss in CL response capacity to stimulating agents. It further demonstrates that a direct relationship exists between the variations in C3a antigen plasma levels and whole blood CL production observed in the CUP group of patients from T0 to T15 (delta 15) of dialysis. This relationship is characterized by a positive correlation between delta 15 C3a and delta 15 basal CL levels in afferent and efferent lines, and a negative correlation between delta 15 C3a and delta 15 CL response capacity values in the efferent but not afferent line. In contrast, no significant correlation with the type of dialysis membrane could be demonstrated between the variations in polymorphonuclear neutrophil counts and C3a antigen levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of first and long-term dialysis on uraemia-associated increased basal production of interleukin-1 and tumour necrosis factor alpha by circulating monocytes

In a previous study we demonstrated the presence of circulating interleukin-1 (IL-1) in long-term haemodialysis patients and of tumour necrosis factor alpha (TNF alpha) in both long-term haemodialysis and not-yet-dialysed uraemic patients. The present report investigates the spontaneous capacity of monocytes to produce and secrete these two cytokines in 35 long-term haemodialysis patients and 36 uraemic patients undergoing their first dialysis session. Predialytic cell-associated IL-1 concentrations in freshly isolated monocytes were significantly increased both in long-term haemodialysis and first-dialysis uraemic patients compared to normal individuals. In both groups in comparison to normal individuals, although intracellular TNF alpha could not be detected in freshly isolated monocytes, both extracellular IL-1 and TNF alpha concentrations were greatly increased after 20 h of in vitro culture of monocytes in the absence of exogenous stimulation and in serum-free conditions. However, long-term haemodialysis patients showed higher values of secreted IL-1 than not-yet dialysed uraemic patients. During a single dialysis session a significant increase in both cell-associated and secreted IL-1 but not TNF alpha was observed in long-term haemodialysis patients. In contrast, no change in the concentration of either cytokine could be detected at the end of the first dialysis session in uraemic patients. Our findings strongly suggest that factors related to uraemia could be a sufficient signal to initiate intracellular IL-1 protein synthesis and TNF alpha release by monocytes, but that greater IL-1 release could be stimulated during the periodic haemodialysis procedure.

Phagocyte oxidative metabolism in cyclosporine- or placebo-treated patients with insulin-dependent (type I) diabetes mellitus of recent onset

Several lines of evidence suggest that phagocyte-mediated oxidative processes are involved in damage to pancreatic islet cells of Type I insulin-dependent diabetes mellitus (IDDM). This hypothesis, however, has not yet been explored at the clinical onset of IDDM. Similarly, the possibility that cyclosporine A (Cy-A) might exert a selective influence on these phagocyte-mediated oxidative reactions has also not yet been investigated as compared to a placebo. The present study tested both hypotheses in 32 patients with recently diagnosed IDDM who were part of the recent French multicenter randomized therapeutic trial of Cy-A. The production of reactive oxygen intermediates (ROI) by circulating polymorphonuclear (PMN) and mononuclear (MN) phagocytes was determined by luminol-dependent chemiluminescence (CL), both directly within microamounts of whole blood and in purified PMN or MN phagocyte suspensions. Lastly, CL production was measured in the absence (resting CL) and the presence of a panel of particular and soluble phagocyte membrane-stimulating agents. We found that on entry into the trial, i.e. within less than 2 months of the clinical onset of IDDM, patients had normal whole blood CL production in the absence of a stimulating agent and upon phagocytic challenge with latex or opsonised zymosan particles. By contrast, whole blood CL responses to soluble stimuli such as phorbol myristate acetate (PMA), concanavalin A (Con-A) and F Met-Leu-Phe (FMLP) were significantly higher than in the control group of 52 normal subjects (P less than 0.01). In purified PMN and MN phagocyte suspensions, both resting and stimulated CL productions were normal, regardless of the type of stimulating agent. After 3 months of treatment, whole blood CL responses to Con-A and FMLP returned to almost normal levels in patients treated with Cy-A (15 cases) but not in those receiving the placebo (17 cases); PMA-induced CL responses were also decreased, but this was found in both groups of patients. In purified phagocyte suspensions we detected no effect of Cy-A on PMN, whereas MN phagocytes from Cy-A-treated patients showed reduced CL responses to FMLP but not to other stimuli. Altogether, these results demonstrate for the first time that the capacity of circulating PMN and MN phagocytes to generate ROI is normal at the clinical onset of IDDM and suggest that circulating substances increase oxidative responses to soluble, but not particulate, stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of uremia and hemodialysis on circulating interleukin-1 and tumor necrosis factor alpha

Interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) were determined in the plasma of long-term hemodialysis (HD) patients and uremic (UR) patients undergoing their first dialysis session using either cellulosic (CUP) or synthetic (PAN-AN 69) membrane-equipped dialyzers. In long-term HD patients, plasma IL-1 and TNF alpha levels were significantly increased compared to their levels in normal subjects. During a single dialysis session, a significant increase in IL-1 but not in TNF alpha was observed. In not yet dialyzed UR patients, IL-1 plasma levels did not differ from those observed in normal subjects. By contrast, TNF alpha was found significantly increased although less than in long-term HD patients. During the first dialysis session, no significant increase was observed in the levels of either monokine. Lastly, regardless of the group of patients, no significant influence of the dialysis membrane could be detected, suggesting that the observed changes are not exclusively secondary to the activation of complement. Altogether, these results suggest that the passage of the blood through the extracorporeal dialysis circuit triggers the secretion of IL-1 and further exacerbates that of TNF alpha by monocytes. The presence of increased TNF alpha in the plasma of first-dialysis UR patients suggests that factors unrelated to dialysis contribute to the activation of monocytes in these patients. Lastly, the concomitant presence of IL-1 and TNF alpha in the plasma of long-term HD patients could be responsible for some of the clinical features observed in these patients, and provides strong evidence favoring the concept that HD can be assimilated to a recurrent acute-phase inflammatory response.

Role of oxygen-dependent mechanisms in monoclonal-antibody-induced lysis of normal T cells by phagocytes. II. Murine phagocytes

In the first part of this study, we reported that antibody-dependent cellular cytotoxicity (ADCC) mediated by human polymorphonuclear (PMN) and mononuclear (MN) phagocytes against anti-T-cell monoclonal-antibody-(mAb)-coated T lymphocytes, is mainly dependent upon the generation of reactive oxygen intermediates (ROI) for PMN, whereas MN-mediated ADCC depends on both oxidative and non-oxidative cytolytic events. Using mouse effector cells from various organs and at various maturation or activation states, the present report shows that in this ADCC model against mAb-coated normal T cells, resident spleen (SPC) and peritoneal exudate (PEC) cells selectively bound and developed oxidative responses to these mAb-coated normal target cells but remained ineffective in ADCC. Similar data were obtained with inflammatory recruited (thioglycollate-elicited or Biogel granuloma-induced) macrophages, whereas immunologically activated macrophages (from BCG-treated mice) mediated both strong oxidative responses and potent ADCC reactions. In contrast, and as in the human system, both resident (from bone marrow) and inflammatory PMN phagocytes exerted significant lysis of these mAb-sensitized normal lymphoid cells. These findings, which are similar to those reported in ADCC against tumour target cells, strongly suggest that the nature (normal or tumoral) of the target cell does not influence the lytic mechanisms of macrophage-mediated ADCC and that these latter require activated macrophages and, like PMN, involve strong (if not exclusive) ROI participation.

Chemiluminescence monitoring of phagocyte oxidative metabolism in mice bearing polyacrylamide induced granulomas

A technical protocol was recently described by Fauve et al. (J. Immunol. Methods 1983, 64, 345) for inducing subcutaneous granuloma with polyacrylamide microbeads. The present study using this technique demonstrates that the capacity of host phagocytes to generate reactive oxygen species can be easily monitored by chemiluminescence, both locally in granuloma infiltrating cells and at sites remote from the inflammatory reaction, i.e., within microamounts of whole blood and in spleen cells. We observed that both resting and stimulated (zymosan or phorbol-myristate acetate) production by C57BL/6 mouse phagocytes are significantly higher in granulomas induced with high porosity polyacrylamide beads (P300) than in those induced with beads of low polyacrylamide porosity (P4). Since this selective modulation of phagocyte oxidative metabolism is also detectable within microamounts of whole blood and in spleen cells, it could serve as a model for investigating the role of reactive oxygen species in the inflammatory reaction.

Hemodialysis membrane-induced activation of phagocyte oxidative metabolism detected in vivo and in vitro within microamounts of whole blood

The production of reactive oxygen species by phagocytes from uremic patients undergoing hemodialysis was monitored by chemiluminescence (CL) within microamounts of whole blood or isolated polymorphonuclear (PMN) cells, and compared on the basis of the dialysis membrane, cuprophane (CUP) or polyacrilonitrile (PAN). Compared to control subjects, resting and stimulated CL (with latex, zymosan, phorbol myristate acetate (PMA) but not formyl-methionyl-leucyl-phenylalanine (FMLP) were decreased in 10(-2) diluted blood sampled before dialysis. After 15 min of dialysis (ti), resting whole blood (10(-1) and 10(-2) diluted) CL increased sharply in patients dialyzed with the CUP but not the PAN membrane, while it returned to its predialysis level at the end of the session. This sharp resting CL increase found in whole blood at ti was not observed in isolated PMN cells except when tested with ti plasma from CUP dialyzed patients, suggesting that it was mediated via activated plasma compounds. In vitro treatment of normal blood, plasma, and isolated PMN cells with CUP membrane fragments reproduced this in vivo dialysis-induced activation of phagocyte oxidative metabolism strikingly and demonstrated additionally the requirement of complement for its induction. We propose this model as an effective means of evaluating dialysis membrane biocompatibility.

Effect of LPS on the oxidative metabolism of peritoneal and spleen cells from LPS sensitive and resistant mice

The influence of LPS on peritoneal and spleen cell oxidative metabolism was investigated in LPS sensitive (C57BL/6) and LPS resistant (C3H/HeJ) mice following intraperitoneal or subcutaneous injection, by measurement of chemiluminescent (CL) responses to latex particles. In C57BL/6 mice, LPS induced a marked increase in peritoneal and spleen cell CL responses, regardless of the route of injection. On the 2nd day, the effect of LPS on peritoneal cells could be fully explained by an inflammatory reaction, while on the 4th day it could be related to an "activated state" of peritoneal macrophages. In contrast, such an in vivo effect of LPS in peritoneal or spleen cell CL responses was not found in C3H/HeJ mice except on the 2nd day following the injection and with the highest LPS dosage and could be totally due to the LPS induced inflammatory reaction. In vitro studies showed that extremely low concentration of LPS increased CL response capacities of C57BL/6 spleen cell to latex particles. In contrast, CL responses from C3H/HeJ spleen cells remained unaffected by LPS except when submitted to concentrations which proved toxic for the sensitive strain CL producing cells. These results lend additional evidence for the involvement of reactive oxygen species (ROS) in the metabolic consequences of LPS-induced macrophage activation.

Monoclonal antibodies against T cell differentiation antigens initiate stimulation of monocyte/macrophage oxidative metabolism

Within the first minute after incubation with the mouse anti-human T cell orthoclone monoclonal antibodies OKT3, OKT4, and OKT8, and in the absence of complement, human monocytes generate a burst of highly reactive oxygen metabolites as detected by a luminol-dependent photometric chemiluminescence (CL) assay. The kinetics of the CL responses to these antibodies are identical to that induced by OKM1, the monoclonal antibody to human monocytes and granulocytes. With regard to CL response intensities, OKM1 induces the maximal response and those of OKT3, OKT4, and OKT8 closely reflect the proportion of T cell subsets recognized by these antibodies in peripheral blood. This reaction is also observed when monoclonal antibodies against mouse Lyt surface determinants (Lyt-1 and Lyt-2) and Thy-1 antigen are tested against murine spleen cells. This murine model was further used to investigate the specificity and the mechanism of this reaction. It was demonstrated that the CL response is Lyt antigen specific, occurs upon addition of monoclonal IgG but not IgM antibodies, requires the concomitant presence of CL-producing cells (CLPC) (promonocytes, monocytes, macrophages, and/or granulocytes) and of fully differentiated T cells, and lastly, is mediated via a T cell opsonization process. Selective blockade of bone marrow cell Fc receptors (FcR II) with monoclonal anti-mouse FcR II antibody inhibits the CL response to IgG2b anti-T cell antibody-coated thymocytes and thus strongly suggests that the stimulation of CLPC oxidative metabolism in this model results from the binding of opsonized T cells to plasma membrane Fc receptors. These observations lend additional support to increasing evidence that the initiation of effector functions by monoclonal anti-T cell antibodies may be strictly dependent upon the presence of monocytes and/or macrophages.

Monoclonal antibodies against T cell differentiation antigens initiate stimulation of monocyte/macrophage oxidative metabolism

Within the first minute after incubation with the mouse anti-human T cell orthoclone monoclonal antibodies OKT3, OKT4, and OKT8, and in the absence of complement, human monocytes generate a burst of highly reactive oxygen metabolites as detected by a luminol-dependent photometric chemiluminescence (CL) assay. The kinetics of the CL responses to these antibodies are identical to that induced by OKM1, the monoclonal antibody to human monocytes and granulocytes. With regard to CL response intensities, OKM1 induces the maximal response and those of OKT3, OKT4, and OKT8 closely reflect the proportion of T cell subsets recognized by these antibodies in peripheral blood. This reaction is also observed when monoclonal antibodies against mouse Lyt surface determinants (Lyt-1 and Lyt-2) and Thy-1 antigen are tested against murine spleen cells. This murine model was further used to investigate the specificity and the mechanism of this reaction. It was demonstrated that the CL response is Lyt antigen specific, occurs upon addition of monoclonal IgG but not IgM antibodies, requires the concomitant presence of CL-producing cells (CLPC) (promonocytes, monocytes, macrophages, and/or granulocytes) and of fully differentiated T cells, and lastly, is mediated via a T cell opsonization process. Selective blockade of bone marrow cell Fc receptors (FcR II) with monoclonal anti-mouse FcR II antibody inhibits the CL response to IgG2b anti-T cell antibody-coated thymocytes and thus strongly suggests that the stimulation of CLPC oxidative metabolism in this model results from the binding of opsonized T cells to plasma membrane Fc receptors. These observations lend additional support to increasing evidence that the initiation of effector functions by monoclonal anti-T cell antibodies may be strictly dependent upon the presence of monocytes and/or macrophages.

Modulation of human granulocyte and monocyte chemiluminescence responses: evidence for distinct free radical generating systems

Using a previously described luminol-dependent photometric chemiluminescence (CL) assay we have investigated the relative significance of the free radicals in the CL phenomenon associated with the respiratory burst of granulocytes and monocytes. The O-2 scavenger, superoxide dismutase, quenches approximately 50% of CL emission from resting and stimulated cells of both types. CL production from granulocytes and monocytes, in the presence of catalase, indicates that H2O2 plays a much less significant role in monocyte light emission than in that of granulocytes. Sodium azide, an 1O2 scavenger and potent inhibitor of peroxidase, and sodium benzoate, an OH. scavenger, both induced 90% reductions of light output from both cell types in resting or stimulated states. The distinct effects of cytochalasins on granulocytes and monocytes further suggest distinct CL generating mechanisms for each cell type. No difference was observed between granulocyte and monocyte CL response in chronic granulomatous disease (CGD) and other clinically related but unknown phagocyte metabolic disorders, whereas selective CL response abnormalities were observed in patients with severe isolated phagocyte chemotaxis defects.

Chemiluminescence in microamounts of whole blood for investigation of the human phagocyte oxidative metabolism function

The present study was undertaken in order to investigate more precisely the chemiluminescence (CL) phenomenon and thus the generation of oxygen-free radical products by polymorphonuclear granulocytes (PMN) and monocytes (MN) as takes place in whole blood. A luminol-dependent photometric assay previously devised in our laboratory was used to simultaneously evaluate the CL production by resting cells and cells stimulated by a series of particulate and soluble surface-stimulating agents: latex particles, opsonized zymosan, phorbolmyristate acetate and concanavalin A. In order to quantify the overall light-quenching effect of blood on light emission and subsequently to determine the actual CL output by PMN and MN present in whole blood, Pholad luciferin was used as a constant source of light. This approach allowed the observation that CL production by cells in whole blood was of a much higher order than that of isolated cells. Application of this CL assay to investigate oxygen-free radical production in patients suffering from chronic granulomatous disease and related phagocytic cell disorders permitted the early and accurate diagnosis of such genetic disorders. Of great interest were the preliminary results obtained in patients with inflammatory diseases showing a marked discrepancy between background CL emission from whole blood and isolated cells. In conclusion, this investigation of PMN and MN oxidative metabolism in whole blood allows for the precise evaluation of CL production by phagocytic cells in an in vitro situation which closely mirrors their in vivo environment. Such advantages encourage its widespread application in both human and experimental physiopathology in order to further elucidate the in vivo role of oxygen-free radicals in the mechanisms of host resistance against pathogens.

Flash detection of anti-H-2 antibodies using chemiluminescence, without complement

Within the first minute following their exposure to a specific anti-H-2 serum and in the absence of complement, murine spleen cells generate a chemiluminescence phenomenon which is precisely measurable by photometry in the presence of luminol. The reaction lasts approximately 10 to 20 minutes, it also generated by bone marrow and, although weakly, by peritoneal cells. In contrast, thymus cells remain totally unresponsive. The striking inhibition of the phenomenon in the presence of superoxide dismutase confirmed that it is indeed due to O2(-). This rapid, simple, inexpensive, extremely sensitive and reproducible technique offers the advantage of focusing on the histocompatibility antigens borne by monocytes, macrophages and granulocytes. Lastly, this O2(-) production triggered by anti-H-2 antibodies should be kept in mind when discussing the mechanism of vascular damage in allograft rejection.