[Experimental nephrology unit: overview and research projects]

After a short historical background of the Laboratory, the main research topics--renal toxicology, physiopathology of renal interstitial fibrosis and hormonology--are described in the perspective of a partnership between research clinicians and full time scientists. National as well as international scientific collaborations underline the need of combining expertises, stimulating also the training of youngest colleagues to the experimental approach of their future discipline.

First Report of Phytophthora ramorum on Ornamental Plants in France

In April 2002, Phytophthora ramorum was associated with twig blight and brown spots on Rhododendron spp. leaves from a nursery in France. The isolate was identified by its morphological characters on V8 agar: slow growth, deciduous and semipapillate sporangia, and abundant production of large chlamydospores (3). The identification was confirmed by ITS rDNA sequencing. During 2002, P. ramorum was also isolated from diseased Viburnum tinus and V. × bodnantense plants exhibiting symptoms of wilting and stem base discoloration. Subsequently, repeated surveys for P. ramorum were carried out in nurseries and areas surrounding nurseries throughout France. Since 2004, a large range of known hosts were investigated in approximately 2,000 nurseries and 200 other sites each year. P. ramorum was detected exclusively in nurseries at 29 locations in 2002, 9 in 2003, 23 in 2004, 17 in 2005, and 19 in 2006. Rhododendron spp. and occasionally V. tinus were the major hosts. In addition, the pathogen was detected for the first time on Pieris japonica in two nurseries in 2005 and on Camellia sp. in one nursery in 2006 from plants exhibiting leaf and twig blight. In both cases, P. ramorum had already been detected on Rhododendron spp. in the same nurseries. Most of the infected plants were found in northwestern France (Bretagne and Pays-de-la-Loire), or came from this region, which is the main rhododendron-growing area in France. In some cases, plants were imported from Belgium or the Netherlands. P. ramorum was also detected in a nursery in soil close to diseased Rhododendron spp. plants and pond water used for irrigation by using a combination of baiting with Rhododendron spp. leaves and PCR assay with species-specific primers (1). Overall, approximately 1% of the investigated nurseries were found positive each year, and this ratio was quite stable from 2004 to 2006. To date, P. ramorum has not been detected outside of nurseries, although many surveys were conducted on the west coast of France where the risk is considered to be high because of a favorable mild and humid climate and the presence of suitable hosts. In addition, 78 isolates of P. ramorum collected between 2002 and 2004 on Rhododendron spp. and V. tinus were found to be of A1 mating type based on pairings with P. cryptogea A1 and A2 mating types (2). References: (1) K. J. Hayden et al. Phytopathology 94:1075, 2004. (2) S. Werres and B. Zielke J. Plant Dis. Prot. 110:129, 2003. (3) S. Werres et al. Mycol. Res. 105:1155, 2001.

Risk factors for the phytophthora-induced decline of alder in northeastern france

ABSTRACT A lethal disease of common alder caused by Phytophthora alni, a new hybrid pathogen, has been spreading in Europe since the early 1990s. In 2004, we conducted an epidemiological survey in northeastern France to determine disease frequency and to investigate the impact of environmental factors on disease prevalence. Seventy-eight plots in the Rhin-Meuse basin were investigated. The survey was structured to enable critical examination of the possible impact of nitrogen pollution of the river water on disease prevalence. P. alni-induced alder decline was common throughout northeastern France. Altogether, disease was found in 80% of the plots containing alder, with 16% of all the alders affected. Striking differences existed between watercourse types. Lower proportions of diseased alders were found in watercourse types with rapid water flow, such as mountain streams of the Vosges and piedmont or watercourses on steep calcareous slopes, than in the slow watercourses of the low-lying valleys of the calcareous plateaus and of the clayey plains. Disease prevalence was not related to the total oxidized nitrogen concentration of the water. However, prevalence increased with the mean summer temperature of the river water and where clayey soils were found in the river banks. The results of this work can be used for the assessment of P. alni-induced alder decline risks in affected European countries and in areas where the disease could be introduced.

Orofacial granulomas after injection of cosmetic fillers. Histopathologic and clinical study of 11 cases

BACKGROUND

Purposely, cosmetic injections in orofacial tissues of various resorbable, biodegradable, or permanent fillers may be followed by development of foreign-body granulomas. The aim of this article is to contribute to the histologic identification of the filler material.

METHODS

Histologic and clinical features of 11 cases of granulomas on orofacial fillers are described.

RESULTS

Only 3/11 patients knew the nature of the injected product. Four histologic patterns were found: (i) Artecoll, (ii) Dermalive, and (iii) New-Fill granuloma, all three of the classic giant cell granuloma type, differing in respect of foreign particles; and (iv) Liquid Silicone granuloma, which featured a cystic and macrophagic type. Information was often missing or misleading, patients or practitioners being reluctant to give the details.

CONCLUSION

Increasing demand for orofacial tissue augmentation makes pathologists face new, and sometimes, puzzling granuloma types. Identification of the foreign product might be required for therapeutic or medico-legal reasons.

Partial Resistance to Melampsora larici-populina Leaf Rust in Hybrid Poplars: Genetic Variability in Inoculated Excised Leaf Disk Bioassay and Relationship with Complete Resistance

ABSTRACT Inoculated excised leaf disk technique allows decomposition of poplar partial resistance to Melampsora larici-populina leaf rust into key epidemiological components such as latent period (LP), uredinia number (UN), uredinia size (US), and spore production (SP) for a given M. larici-populina strain under controlled environmental conditions. Three hundred thirty-six genotypes from an interspecific Populus deltoides x P. trichocarpa F(1) progeny segregating for complete resistance to M. larici-populina strain 93ID6 were inoculated with M. larici-populina strain 93CV1. This strain was able to infect the whole family, except few probable recombinants. LP, final UN, and final US after one infectious cycle proved to be relevant complementary descriptors of partial resistance. Area under the disease progress curve and other parameters of uredinia appearance dynamics did not yield additional information. Indirect assessment of SP by US scoring was reliable and easy to access compared with direct spore counting. UN was the only trait for which a doubling of the inoculum pressure level had a significant effect, leading to greater differentiation between genotypes. Consistent with previous studies is the clear relationship between presence of complete resistance against M. larici-populina strain 93ID6 and higher partial resistance to M. larici-populina strain 93CV1 (32% longer LP, 76% smaller UN, and 34% smaller US). In the subpopulation compatible with 93ID6, bimodal distribution of genotypic means for US suggested implication of a major gene inherited from the P. trichocarpa parent. Residual variation was noted for the three epidemiological components, suggesting that additional genes might condition these quantitative traits.

Solid state and solution studies of lanthanide(III) complexes of cyclohexanetriols, models of the coordination sites found in sugars

This report covers studies in trivalent lanthanide complexation by two simple cyclohexanetriols that are models of the two coordination sites found in sugars and derivatives. Several complexes of trivalent lanthanide ions with cis,cis-1,3,5-trihydroxycyclohexane (L(1)()) and cis,cis-1,2,3-trihydroxycyclohexane (L(2)()) have been characterized in the solid state, and some of them have been studied in organic solutions. With L(1)(), Ln(L)(2) complexes are obtained when crystallization is performed from acetonitrile solutions whatever the nature of the salt (nitrate or triflate) [Ln(L(1)())(2)(NO(3))(2)](NO(3)) (Ln = Pr, Nd); [Ln(L(1)())(2)(NO(3))H(2)O](NO(3))(2) (Ln = Eu, Ho, Yb); [Ln(L(1)())(2)(OTf)(2)(H(2)O)](OTf) (Ln = Nd, Eu). Lanthanum nitrate itself gives a mixed complex [La(L(1)())(2)(NO(3))(2)][LaL(1)()(NO(3))(4)] from acetonitrile solution while [La(L(1)())(2)(NO(3))(2)](NO(3)) is obtained using dimethoxyethane as reaction solvent and crystallization medium. With L(2)(), Ln(L)(2) complexes have also been crystallized from methanol solution [Ln(L(2)())(2)(NO(3))(2)]NO(3), (Ln = Pr, Nd, Eu). Single-crystal X-ray diffraction analyses are reported for these complexes. Complex formation in solution has been studied for several triflate salts (La, Pr, Nd, Eu, and Yb) with L(1 )()and L(2)(), respectively in acetonitrile and in methanol. In contrast to the solid state, both structures Ln(L) and Ln(L)(2) equilibrate in solution, as was demonstrated by low-temperature (1)H NMR and electrospray ionization mass spectrometry experiments. Competing experiments in complexing abilities of L(1)() and L(2)() with trivalent lanthanide cations have shown that only L(2)() exhibits a small selectivity (Nd > Pr > Yb > La > Eu) in methanol.

Role of complement and platelet-activating factor in the stimulation of phagocytosis and reactive oxygen species production during haemodialysis

BACKGROUND

Neutrophil phagocytic functions have been studied extensively in haemodialysis (HD) patients; however, results are contradictory and the mechanisms that modulate phagocytosis and oxidative burst during dialysis are not completely understood.

METHODS

The present study investigated neutrophil functions in a selected population of patients before and during clinical dialysis with cuprophane, and polyacrylonitrile (AN69) membranes. We measured phagocytosis of Escherichia coli and intracellular hydrogen peroxide (H2O2) production by flow cytometry in whole blood.

RESULTS

Before dialysis, neutrophils from HD patients showed normal phagocytic capability and H2O2 formation. Phagocytosis of FITC-E. coli was significantly stimulated in cuprophane but not AN69-treated patients. Spontaneous and stimulated H2O2 production was enhanced with both cuprophane and AN69 membranes. We then investigated in vitro the role of complement and platelet-activating factor (PAF) in the activation of neutrophils. Incubation of whole blood with C5a increased phagocytosis but not H2O2 production. On the contrary, the addition of synthetic PAF showed a markedly stimulated H2O2 production without increase in phagocytosis. Moreover, during dialysis with formaldehyde-reused cuprophane, complement activation was abolished and phagocytosis was no longer enhanced, while the stimulation of H2O2 production persisted. In addition, we also excluded a particular role of the membrane itself in the activation of neutrophils.

CONCLUSION

We demonstrated that in a selected population of HD patients, neutrophils exhibit normal phagocytic capability and normal intracellular H2O2 production. During dialysis, the stimulation of phagocytosis observed with cuprophane is complement dependent, whereas the enhanced H2O2 production observed with both cuprophane and AN69 membranes might be related to PAF production.

Role of the cholinergic pathway in mediating platelet-activating factor-induced pulmonary dysfunctions in unsedated calves

The purpose of this study was to investigate the possible role of the cholinergic pathway in mediating platelet-activating factor (PAF)-induced pulmonary dysfunctions in unsedated calves. In a placebo group, PAF infusion challenge induced significant dysfunctions in the pattern of breathing [a significant increase in respiratory rate (RR) and a significant decrease in tidal volume (VT)], the mechanics of breathing [a significant increase in total lung resistance (RL) and a significant decrease in dynamic lung compliance (CLdyn)] and gas exchange, whereas in atropine pre-treated calves, PAF infusion challenge induced a significant increase in RR, VT and HR and a significant decrease in CLdyn. The RL increase was prevented by atropine pre-treatment. On the basis of our findings, we suggest that, in cattle, the PAF-induced pattern of breathing dysfunctions and the diffuse bronchoconstriction and microvascular leakage of small airways are not mediated through the cholinergic pathway. By contrast, our data suggest that PAF-induced bronchoconstriction of upper airways is at least partly mediated through muscarinic receptors.

Efficacy of oral immunotherapy on respiratory infections in hemodialysis patients: a double-blind, placebo-controlled study

BACKGROUND

Hemodialysis (HD) patients suffer from several immune defects that make them prone to develop bacterial infections, in particular respiratory tract infections (RTIs).

PATIENTS AND METHODS

As previous studies have shown that oral immunotherapy with an immunomodulating bacterial extract (IBE) is effective against RTIs, we decided to test its efficacy and safety in HD patients during a double-blind placebo-controlled prospective study. 40 HD patients with a documented history of RTIs in the previous year were treated for 24 weeks of the endemic season with one capsule daily of IBE (n = 21) or placebo (PL, n = 19). Clinical examinations, measurements of Mac-1 and gp150.95 on circulating phagocytes and routine laboratory evaluations were performed at week 0, 4, 12 and 24. Patients were also examined at each dialysis session allowing an accurate recording of any infectious episode, its treatment and of any untoward effect.

RESULTS

During the last period of the study (weeks 13-24), IBE significantly reduced the number of patients with RTIs and consequently of antibiotic treatment courses as compared to PL (p = 0.018), whereas no difference was detected between IBE and PL during periods I (weeks 0-4) and II (weeks 5-12). There was no difference between IBE and PL for other, non respiratory infections. IBE was associated at several time points with an increased expression on phagocytes of adhesion molecules involved in phagocytosis (Mac-1 and gp150.95). However, the expression of these molecules was not predictive for the occurrence of RTI. IBE was on the whole as well tolerated as PL, 7 patients presented side effects (5 IBE, 2 PL, NS) which led to drop-out in 4 cases (3 IBE, 1 PL). No serious side effect was recorded, gastrointestinal upset being the most prevalent type.

CONCLUSION

The results of this study indicate that immunomodulation with selected bacterial extracts constitutes a promising approach for the prevention of bacterial airway infections in groups at risk, such as HD patients.

Direct activation of human peritoneal mesothelial cells by heat-killed microorganisms

OBJECTIVE

The aim of the study was to determine if human peritoneal mesothelial cells (HPMCs) can be activated directly by bacterial products contained in preparations of heat-killed Escherichia coli and staphylococci.

SUMMARY BACKGROUND DATA

It has been shown recently that cytokine-activated HPMCs produce the inflammatory mediators, interleukin-1, interleukin-6, interleukin-8, and macrophage chemotactic protein-1. Studies concerning the effects of bacterial products on HPMCs are scarce and have not yielded conclusive results.

METHODS

Growth-arrested HPMC monolayers were prepared from cell suspensions obtained by enzymatic disaggregation of small pieces of omentum. They were incubated for 24 hours with heat-killed E. coli (ATCC 25922), heat-killed staphylococci (ATCC 25933), or E. coli lipopolysaccharide, and the release of various cytokines in the culture media was measured by radioimmunoassays or enzyme-linked immunosorbent assays. Results were expressed as mean +/- standard error of the mean in picograms per milliliter of supernatant and analyzed with the Wilcoxon test; p values of less than 0.05 were considered significant.

RESULTS

Baseline production of interleukin-6, interleukin-8, the chemokine "regulated upon activation, normal T cell expressed and secreted" (RANTES), and macrophage chemotactic protein-1 varied widely from one omental preparation to the other. E. coli increased the release of these mediators: from 1206 +/- 316 pg/mL to 8480 +/- 2189 pg/mL for interleukin-6, from 285 +/- 58 pg/mL to 3164 +/- 1053 pg/mL for interleukin-8, from 7 +/- 5 pg/mL to 684 +/- 264 pg/mL for RANTES, and from 2212 +/- 346 pg/mL to 7726 +/- 1473 pg/mL for macrophage chemotactic protein-1. Heat-killed staphylococci did not alter significantly the production of RANTES or macrophage chemotactic protein-1 but increased the production of the two other cytokines from 1325 +/- 389 pg/mL to 2206 +/- 523 pg/mL for interleukin-6 and from 318 +/- 70 pg/mL to 819 +/- 265 pg/mL for interleukin-8.

CONCLUSIONS

The authors' results show that HPMCs are able to react to a direct stimulation with heat-killed microbes. They suggest that HPMCs, as well as resident macrophages, participate actively in the initiation and possibly in the modulation of intraperitonen inflammatory reactions.

Cuprophane haemodialysis induces upregulation of LPS receptor (CD14) on monocytes: role of complement activation

BACKGROUND

The CD14 molecule is a high-affinity receptor for the complex formed by lipopolysaccharide (LPS) and LPS-binding protein.

METHODS

We examined by flow cytometry the effect of in vitro and in vivo haemodialysis on cuprophane membrane and recombinant C5a on the expression of CD14 molecules at the surface on monocytes. Monocyte CD14 expression was also studied during in vitro and in vivo haemodialysis on polyacrylonitrile AN69 membrane.

RESULTS

In vitro haemodialysis of whole blood from healthy volunteers on cuprophane membrane resulted within 30 min in upregulation of monocyte CD14 expression. The reuse of the cuprophane membrane abolished both complement activation and CD14 upregulation. Moreover, incubation of whole blood with recombinant C5a led to an increased monocyte CD14 expression supporting a role for complement activation in the rapid cuprophane-induced CD14 upregulation. During AN69 dialysis which is not associated with complement activation in the blood phase, monocyte CD14 expression did not change during the first 60 min but was significantly increased after 3 h of in vitro haemodialysis. This late increase might be related to the presence of complement activation products adsorbed on the membrane. In vivo dialysis on cuprophane membrane also resulted in early monocyte CD14 upregulation as indicated by higher CD14 expression found after 60 min on monocytes obtained from the efferent as compared to the afferent line of the dialyser, a phenomenon that was not observed during haemodialysis on AN69 membrane.

CONCLUSION

Haemodialysis on the complement-activating cuprophane membrane induces the rapid upregulation of the CD14 LPS-receptor on monocytes.

Effects of ultrapure and non-sterile dialysate on the inflammatory response during in vitro hemodialysis

Several studies support the hypothesis that bacterial contamination of the dialysate stimulates the inflammatory response to hemodialysis (HD) and increases the long-term morbidity of HD patients; this phenomenon could also be modulated by the nature of the HD membrane. Therefore, this study was designed to compare the effects of non-sterile (NSBD, mean endotoxin content +/- SEM 97 +/- 22 EU/ml) and ultrapure bicarbonate dialysate (UPBD, sterile and pyrogen-free, obtained by ultrafiltration through polyamide) on several aspects of the inflammatory reaction during in vitro HD. The HD sessions (7 in each experimental group) were performed using miniaturized new cuprophane (CU) and polyacrylonitrile (PAN) hollow fiber dialyzers, and closed dialysate and blood circuits (the latter filled with heparinized blood from healthy donors). Plasma C3aDesarg levels were significantly increased after 15 minutes (t1) and increased further after three hours (t2) of CU HD, while during PAN dialysis they decreased from t0 to t1 and t2; however, no difference appeared between experiments with NSBD and UPBD. Granulocyte (PMN) and monocyte (MNC) expression of LFA-1, Mac-1, and CD45 at the start (t0), t1 and t2 was quantitated by flow cytometry analysis, after staining of the cells with specific fluorescinated monoclonal antibodies. In contrast with published data of in vivo HD, LFA-1 was overexpressed at t1 and peaked at t2, which suggests that the leukocytes expressing more LFA-1 leave the systemic circulation during in vivo HD. During CU HD, Mac-1 and CD45 on PMN and MNC were significantly increased at t1, and still more at t2. During PAN HD, Mac-1 and CD45 remained unchanged at t1, but increased significantly at t2 on PMN as on MNC. Again, no significant difference was found between NSBD and UPBD in LFA-1, Mac-1 and CD45 expression on PMN and MNC, during both CU and PAN HD. AFter three hours of dialysis, plasma levels of TNF-alpha, but not of IL-6, were significantly increased with CU and PAN. Again, no difference appeared when NSBD and UPBD were compared. Moreover, the lack of influence of bacterial contamination of the dialysate on TNF-alpha production was confirmed when MNC were cultured up to 24 hours after the end of the HD session. We conclude that complement activation products, either in plasma (CU) of those adsorbed on the HD membrane (CU and PAN) play the major role in the overexpression of beta 2-integrins and CD45 by PMN and MNC during HD. Also, bacterial products (at the levels that can be found in clinical conditions) do not influence either beta 2-integrin overexpression or TNF-alpha production induced by the dialysis membrane.

Impaired phagocyte responses to lipopolysaccharide in paroxysmal nocturnal hemoglobinuria

Bone marrow-derived cells from patients suffering from paroxysmal nocturnal hemoglobinuria (PNH) show a defect in the expression of phosphatidylinositol-anchored membrane proteins, including the CD14 molecule. Blocking experiments with anti-CD14 monoclonal antibodies have shown that lipopolysaccharide (LPS)-induced tumor necrosis factor alpha production by monocytes depends on the interaction between CD14 and a complex formed by LPS and LPS-binding protein. We used a whole-blood model to examine the LPS-induced production of tumor necrosis factor alpha and interleukin-6 in PNH patients and healthy volunteers. At low endotoxin concentrations (1 ng/ml), PNH patients displayed a marked defect in the production of both cytokines, whereas at high LPS concentrations (100 ng/ml), cytokine production was similar to that in healthy volunteers. Using flow cytometry, we also studied the expression of the adhesion molecules Mac-1 (CD11b/CD18) and ICAM-1 (CD54) by monocytes and granulocytes after LPS stimulation. Compared with phagocytes from healthy volunteers, CD14-deficient cells showed poor Mac-1 and ICAM-1 upregulation when whole blood was stimulated with LPS (1 ng/ml), whereas their response to higher LPS doses (100 and 1,000 ng/ml) was essentially normal. The importance of the CD14 molecule in the activation of phagocytes by low LPS concentrations was confirmed by the inhibitory effect of an anti-CD14 antibody both in healthy volunteers and in PNH patients. Since these patients produce the soluble form of the CD14 molecule, these data suggest that soluble CD14 could play a role in phagocyte responses to LPS. We conclude that, in whole blood, phagocytes from PNH patients show impaired responsiveness to LPS and this phenomenon is most probably related to their defect in expression of membrane CD14.

Androgen excess in women with acne alone compared with women with acne and/or hirsutism

Acne is known to be one of the features of hyperandrogenism. The aim of the present work was to study women with persistent acne and without other evidence of hyperandrogenism, such as hirsutism, alopecia, or irregular menses. Among 87 female patients with acne and/or hirsutism, we defined three groups: group 1 (n = 29), patients having treatment-resistant acne without menstrual disturbance, alopecia, or hirsutism; group 2 (n = 27), patients with acne and hirsutism; and group 3 (n = 31), patients with hirsutism alone. Clinical chemistry criteria for hyperandrogenism were based on elevated values of one or more of the following parameters: plasma testosterone, delta-4-androstenedione, dehydroepiandrosterone, urinary 5 alpha-androstane 3 alpha-17 beta-diol, and 17-ketosteroids (with chromatography). Plasma and urine samples were drawn between the 18th and 25th days of the cycle. Among group 1 patients, we found 25 subjects (86%) with hyperandrogenism, according to these laboratory criteria. The etiologies were: polycystic ovary syndrome (36%), adrenal hypersecretion (40%, of which 12% showed secondary polycystic ovaries), isolated increase in 5 alpha-androstane 3 alpha-17 beta-diol (20%), and hyperandrogenism without diagnosis (4%). The parameters were found to be more elevated in these patients than in a control group of 30 normal volunteer women. In groups 2 and 3, the findings were essentially the same as in group 1, except for increased levels of testosterone and the testosterone/SHBG ratio. Furthermore, it was evident that persistent acne may be an isolated sign of hyperandrogenism.

Severe acne due to chronic amineptine overdose

We report six women with severe acne lesions associated with taking amineptine, a tricyclic antidepressant. The lesions appeared after self-administration of high doses of the drug over long periods of time. They mainly occurred on the face, back, and thorax, but were also found on the extremities and in the perineal region. In five of the six cases, severity of cutaneous lesions appeared to be correlated with degree of overdose. The sixth patient never admitted having taken amineptine. Most of the patients had been unsuccessfully treated with isotretinoin for 18 months. In all six cases, chromatography of urinary 17-ketosteroids showed abnormal peaks and retention times which were different from those usually found for known steroids. In addition, the areas under these peaks were found to be a function of the degree of intoxication and of the clinical severity of the lesions. Mass spectrometry was used to qualitatively study urinary amineptine metabolites, disclosing compounds normally found only in trace amounts, as well as certain others heretofore not described in man. In two of the three patients who stopped taking amineptine, cutaneous lesions subsequently diminished, totally disappearing in the least severe case.