[Membranous nephropathy and crescentic glomerulonephritis]

The most frequent causes of glomerular diseases whose main clinical syndrome are nephrotic syndrome and acute renal failure may have several causes: acute tubular necrosis, thrombosis of renal veins, acute tubulointerstitial nephritis. Infrequently, the association between primary glomerular disease (membranous nephropathy and others) and crescentic glomerulonephritis can cause this clinical picture. We describe a young woman without systemic disease with nephrotic syndrome and acute renal failure secondary to membranous nephropathy and superimposed crescentic glomerulonephritis. She received steroids and cyclophosphamide with stabilization of renal function after two months of follow-up.

Pulsed electromagnetic fields induce peripheral nerve regeneration and endplate enzymatic changes

An experimental study was carried out in rats with the purpose of demonstrating the capacity of pulsed electromagnetic fields (PEMFs) to stimulate regeneration of the peripheral nervous system (PNS). Wistar and Brown Norway (BN) rats were used. Direct sciatic nerve anastomoses were performed after section or allograft interposition. Treatment groups then received 4 weeks of PEMFs. Control groups received no stimulation. The evaluation of the results was carried out by quantitative morphometric analysis, demonstrating a statistically significant increase in regeneration indices (P < 0.05) in the stimulated groups (9000 +/- 5000 and 4000 +/- 6000) compared to the non-stimulated groups (2000 +/- 4000 and 700 +/- 200). An increase of NAD specific isocitrate dehydrogenase (IDH) activity was found along with an increase in the activity of acetyl cholinesterase at the motor plate. The present study might lead to the search for new alternatives in the stimulation of axonal regenerative processes in the PNS and other possible clinical applications.

Interspecific variation of metal concentrations in three bivalve mollusks from Galicia

There has been growing concern about the inflow of metals to the coastal areas because they can be toxic to aquatic and human life. Some studies have demonstrated the existence of species-specific differences in the metal concentrations of mollusks. We compared metal concentrations between Mytilus galloprovincialis, used as a water quality indicator, and two other bivalve species collected for human consumption (Venerupis pullastra and Cerastoderma edule) in different locations on the Galician coast (northwest Spain). M. galloprovincialis was found to be the best zinc and lead accumulator, whereas silver and arsenic were preferentially accumulated by V. pullastra and chromium and nickel by C. edule. Bivalve concentrations of mercury, cadmium, chromium, arsenic, silver, and zinc appeared to be linearly related to environmental concentrations, but this was not the case with copper, nickel, and lead in some species, which indicated that there is a nonlinear accumulation of these metals or an influence of the environmental conditions on species accumulation. The relationship between metal concentration in mussels and in the two other species varied with the metal and the species. In some cases the correlation was high, making it possible to use mussels as bioindicators for the other species. In other cases the correlation was moderate or low, therefore rendering mussels of little or no use in predicting the metal concentrations in the two other species.

High level of coreceptor-independent HIV transfer induced by contacts between primary CD4 T cells

Cell-to-cell virus transmission is one of the most efficient mechanisms of human immunodeficiency virus (HIV) spread, requires CD4 and coreceptor expression in target cells, and may also lead to syncytium formation and cell death. Here, we show that in addition to this classical coreceptor-mediated transmission, the contact between HIV-producing cells and primary CD4 T cells lacking the appropriate coreceptor induced the uptake of HIV particles by target cells in the absence of membrane fusion or productive HIV replication. HIV uptake by CD4 T cells required cellular contacts mediated by the binding of gp120 to CD4 and intact actin cytoskeleton. HIV antigens taken up by CD4 T cells were rapidly endocytosed to trypsin-resistant compartments inducing a partial disappearance of CD4 molecules from the cell surface. Once the cellular contact was stopped, captured HIV were released as infectious particles. Electron microscopy revealed that HIV particles attached to the surface of target cells and accumulated in large (0.5-1.0 microm) intracellular vesicles containing 1-14 virions, without any evidence for massive clathrin-mediated HIV endocytosis. The capture of HIV particles into trypsin-resistant compartments required the availability of the gp120 binding site of CD4 but was independent of the intracytoplasmic tail of CD4. In conclusion, we describe a novel mechanism of HIV transmission, activated by the contact of infected and uninfected primary CD4 T cells, by which HIV could exploit CD4 T cells lacking the appropriate coreceptor as an itinerant virus reservoir.

Immunological and virological study of enfuvirtide-treated HIV-positive patients

OBJECTIVE

To evaluate the predictive value and evolution of immunological and virological parameters related to HIV entry and pathogenesis in patients receiving enfuvirtide (ENF) plus an optimized regimen.

METHODS

A phase III clinical trial substudy of ENF in 22 patients measured virus coreceptor use and sensitivity to ENF, levels of chemokines, cytokines and chemokine receptors, CD38 and HLA-DR expression as markers of T cell activation and ex vivo cell death at baseline and at week 32.

RESULTS

Treatment including ENF reduced HIV viral load (P < 0.001) and increased the CD4 cell count in patients that responded (RP) to treatment (n = 14). Significant (P < 0.05) increases were noted in the RP group in CXCR4 and CCR5 expression in CD4 cells without major differences in chemokine and interleukin-7 levels. A decrease in CD38 expression in the absence of HLA-DR changes was observed in CD4 cells. Apoptosis of peripheral blood mononuclear cells was significantly reduced in the RP group. Coreceptor use or ENF sensitivity of virus isolated at baseline was not associated with virus resistance or response to treatment, which appeared to be related to the activation state (HLA-DR expression) of CD4 cells at baseline.

CONCLUSION

The outcome of ENF-containing treatment could not be associated with HIV coreceptor use at baseline. CD4 cell activation and viral drug resistance were the only markers of treatment response. Changes induced by ENF-containing regimen were seen in HIV coreceptor expression, including an increase in CCR5+CD4+ cells, a decrease in CD38 T cells and a concomitant reduction of T cell apoptosis.

Serotypes and virulence genes of ovine non-O157 Shiga toxin-producing Escherichia coli in Switzerland

Sixty ovine STEC strains were examined with the aim (i) to serotype the strains, (ii) to characterize virulence factors, and (iii) to discuss possible associations between these factors and to assess the potential pathogenicity of these strains for humans. The 60 sorbitol-positive, non-O157 STEC strains belonged to 19 O:H serotypes, whereas 68% were of five serotypes (O87:H16, O91:H-, O103:H2, O128:H2, O176:H4). 52% belonged to serotypes reported in association with HUS. Five serotypes were not previously reported in sheep strains. Of the 47 strains encoding for stx1 variants, 57% were stx1c- and of the 45 encoding for stx2 variants, 80% were stx2d-positive. Eighty-two percent of the strains showed further putative virulence factors: 13% were eae-, 60% ehxA- and 67% saa-positive. The associations between harboring (i) eae and stx1, stx2, ehxA or no saa and (ii) saa and stx1c or stx2d were significant (P<0.05). The strains belonged to 27 seropathotypes (association between serotypes and virulence factors), but 57% belonged to only six and O91:H-stx1 stx2d saa and O128:H2 stx1c stx2d ehxA saa were the most common. Seven of the eight intimin-positive strains harbored eae. Four strains of serotype O103:H2 and O121:H10 harboring stx2, eae and ehxA showed virulence factors typical for strains associated with severe human disease. However, according to the virulence factors, the majority of the ovine non-O157 STEC strains are assumed low-virulence variants. Nevertheless, as long as the contribution and interaction of these factors in milder disease remains unclear P, a certain risk for humans cannot be excluded.

R5 HIV gp120-mediated cellular contacts induce the death of single CCR5-expressing CD4 T cells by a gp41-dependent mechanism

The use of CXC chemokine receptor 4 (CXCR4) and CC chemokine receptor 5 (CCR5) by X4 and R5 human immunodeficiency virus (HIV) envelopes (Env) influences HIV cytopathicity. Here, we have evaluated the role of CCR5 and gp41 in Env-induced cell death occurring during the contacts of uninfected, primary cells with MOLT cells infected with different R5 and X4 HIV isolates. As reported for X4-Env, R5 HIV-infected cells destroyed CD4 T cells expressing the appropriate coreceptor by inducing the formation of syncytia and the death of single target cells. Therefore, only the small (<10%) CCR5+ subset of primary CD4 T cells was sensitive to cellular presentation of R5-Env, and CCR5-CD4 T cells showed complete resistance to R5-Env-mediated cell death. X4- and R5-infected cells killed single primary cells by a common mechanism that was dependent on gp41 function and induced a rapid loss of mitochondrial membrane potential and plasma membrane integrity in target cells. Single-cell death was not affected by the blockade of HIV replication in target cells or G-protein signaling through CXCR4/CCR5. In contrast, caspase inhibition (Z-Val-Ala-Asp-fluoromethylketone) profoundly changed the outcome of cell-to-cell contacts by reducing the number of single dead CD4 T cells and increasing the rate of syncytium formation. In conclusion, X4 and R5 HIV Env share a common gp41-dependent mechanism to kill CD4 T cells during cellular contacts. Env tropism and coreceptor expression but not differential killing mechanisms seem to govern the extent of cytopathic effects induced by HIV infection.

Genetic analysis of sperm and implications of severe male infertility--a review

The use of fluorescence in situ hybridization (FISH) on decondensed sperm heads has allowed to analyse the chromosome constitution of spermatozoa in different populations. In controls, the mean incidence of disomy (including all chromosomes) is about 6.7 per cent; diploidy increases with age, and some individuals may show a special tendency to nondisjunction. Carriers of numerical sex chromosome anomalies show a low incidence of sex chromosome disomies (2.54-7.69 per cent), and the need to screen ICSI candidates for these conditions has to be reconsidered. Carriers of inversions produce from 0 to 54.3 per cent abnormal sperm. Carriers of Robertsonian translocations produce from 3.4 to 36.0 per cent abnormal sperm, and carriers of reciprocal translocations produce from 47.5 to 81.0 per cent abnormal spermatozoa. However, carriers of translocations usually produce more abnormal embryos than expected from these figures. This may be partly related to interchromosomal effects induced by some structural reorganizations. Males with oligoasthenozoospermia, low motility and/or high FSH concentrations show frequent synaptic anomalies, resulting in the production of aneuploid and diploid sperm. Testicular sperm show extremely high rates of chromosomal abnormalities. The risk of recurrent abortion is increased by the presence of chromosome abnormalities in sperm.

[Anti-hypertensive effect of eprosartan in diabetic patients]

OBJECTIVE

Diabetes mellitus seems to induce an special difficulty to control the high blood pressure. This effect is more severe on the SBP. Previous reports suggest that a new angiotensin receptor blocker, eprosartan, might have a higher efficacy to reduce SBP. It has been evaluated the BP decrease obtained with eprosartan in a group of diabetics patients compared to non diabetic patients.

MATERIAL AND METHODS

81 patients were recruited of whom 65 have ended follow-up. 34 patients were diabetics (mean age 66.7+/-10.7 years, 15 men and 19 women) and 31 were non diabetics control patients (mean age 61.8+/-12,8 years, 13 men and 18 women). All patients were treated with (600 mg) once daily. The doses was ingested in the morning. They were made three follow up visits (1, 3 and 6 mo after the first visit).

RESULTS

SBP was significantly decreased both in diabetics (baseline 170.9+/-12.0, final 139.1+/-13.0 mmHg, p < 0.001) and in non diabetics group (baseline 169.9+/-18.0, final 142.0+/-13.3 mmHg, p < 0.001). DBP was also reduced in both groups (diabetics: baseline 92.9+/-9.7, final 78.4+/-8.5 mmHg, p < 0.001; non diabetics: baseline 95.6+/-7.9, final 79.1+/-7.4 mmHg, p < 0.001). Differences between the groups were not significant in any visit. Final BP reduction reached was -31.7/-14.6 mmHg in diabetics vs -27,6/-16,5 mmHg in non diabetics patients (difference is not significant) Pulse pressure changes were not different between the two groups (diabetics, 17.8+/-14.5, vs non diabetics, 11.1+/-13.2 mmHg). Two diabetic patients need a second drug to achieve BP goal and no one in non diabetic group. No adverse effects were reported.

CONCLUSIONS

Eprosartan seems to be an effective drug to reduce SBP, DBP and pulse pressure with the same effectiveness in diabetics and non diabetic patients.

Sperm FISH studies in seven male carriers of Robertsonian translocation t(13;14)(q10;q10)

BACKGROUND

Robertsonian translocation t(13;14) is one of the most common structural reorganization in humans, but meiotic segregation studies in these carriers are still limited. The segregation pattern of the chromosomes involved, the possible influence of the translocated chromosomes on the synapsis and disjunction of other chromosome pairs [interchromosomal effects (ICE)] and the rates of unbalanced spermatozoa produced still deserve attention, not only to obtain a better characterization of the meiotic behaviour of this reorganization, but also to offer carrier couples accurate genetic counselling.

METHODS

Multicolour fluorescence in-situ hybridization was used to analyse the segregation of chromosomes 13 and 14 and the possible occurrence of ICE (on chromosomes 18, 21, 22, X and Y) in seven male carriers of a t(13;14)(q10;q10).

RESULTS AND CONCLUSIONS

The individuals analysed showed a homogeneous segregation pattern, with a clear predominance of alternate segregations resulting in the production of normal/balanced spermatozoa (83-88.23%). A significant increase in the disomy rates for the sex chromosomes, which could be considered as a positive ICE, was observed in two of the carriers analysed.

Fecal shedding of Escherichia coli O157, Salmonella, and Campylobacter in Swiss cattle at slaughter

Fecal samples from 2,930 slaughtered healthy cattle were examined with the following goals: (i) to monitor the shedding of Escherichia coli O157, Salmonella, and Campylobacter in cattle; and (ii) to further characterize the isolated strains. The percentage of the 2,930 samples that tested positive for E. coli O157 by PCR was 1.6%. Thirty-eight strains from different animals that agglutinated with Wellcolex E. coli O157 were isolated. Of the six sorbitol-negative strains, five tested positive for stx2 genes (two times for stx2c and three times for stx2), and one strain tested positive for stx1 and stx2c genes. All sorbitol-negative strains belonged to the serotypes O157:H7- and O157:H7 and harbored the eae type gamma 1 and ehxA genes. The 32 sorbitol-positive strains tested negative for stx genes and belonged to the serotypes O157:H2, O157:H7, O157:H8, O157:H12, O157:H19, O157:H25, O157:H27, O157:H38, O157:H43, O157:H45, and O157:H-. All O157:H45 strains harbored the eae subtype alpha 1 and therefore seem to be atypical enteropathogenic E. coli strains. Whereas none of 1,000 examined samples was positive for Salmonella, 95 of 935 (10.2%) samples were positive for Campylobacter, and all strains were identified as C. jejuni. Sixteen Campylobacter strains were resistant to tetracycline, five were resistant to nalidixic acid/ciprofloxacin, four were resistant to streptomycin, and one was resistant to nalidixic acid/ciprofloxacin and streptomycin. Fecal shedding of zoonotic pathogens in slaughter animals is strongly correlated with the hazard of carcass contamination. Therefore, the maintenance of slaughter hygiene is of crucial importance.

Serotypes, virulence genes, and intimin types of Shiga toxin (verotoxin)-producing Escherichia coli isolates from cattle in Spain and identification of a new intimin variant gene (eae-xi)

A total of 514 Shiga toxin-producing Escherichia coli (STEC) isolates from diarrheic and healthy cattle in Spain were characterized in this study. PCR showed that 101 (20%) isolates carried stx(1) genes, 278 (54%) possessed stx(2) genes, and 135 (26%) possessed both stx(1) and stx(2). Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 326 (63%) and in 151 (29%) of the isolates, respectively. STEC isolates belonged to 66 O serogroups and 113 O:H serotypes (including 23 new serotypes). However, 67% were of one of these 15 serogroups (O2, O4, O8, O20, O22, O26, O77, O91, O105, O113, O116, O157, O171, O174, and OX177) and 52% of the isolates belonged to only 10 serotypes (O4:H4, O20:H19, O22:H8, O26:H11, O77:H41, O105:H18, O113:H21, O157:H7, O171:H2, and ONT:H19). Although the 514 STEC isolates belonged to 164 different seropathotypes (associations between serotypes and virulence genes), only 12 accounted for 43% of isolates. Seropathotype O157:H7 stx(2) eae-gamma1 ehxA (46 isolates) was the most common, followed by O157:H7 stx(1) stx(2) eae-gamma1 ehxA (34 isolates), O113:H21 stx(2) (25 isolates), O22:H8 stx(1) stx(2) ehxA (15 isolates), O26:H11 stx(1) eae-beta1 ehxA (14 isolates), and O77:H41 stx(2) ehxA (14 isolates). Forty-one (22 of serotype O26:H11) isolates had intimin beta1, 82 O157:H7 isolates possessed intimin gamma1, three O111:H- isolates had intimin type gamma2, one O49:H- strain showed intimin type delta, 13 (six of serotype O103:H2) isolates had intimin type epsilon and eight (four of serotype O156:H-) isolates had intimin zeta. We have identified a new variant of the eae intimin gene designated xi (xi) in two isolates of serotype O80:H-. The majority (85%) of bovine STEC isolates belonged to serotypes previously found for human STEC organisms and 54% to serotypes associated with STEC organisms isolated from patients with hemolytic uremic syndrome. Thus, this study confirms that cattle are a major reservoir of STEC strains pathogenic for humans.

HIV-1 envelope glycoproteins-mediated apoptosis is regulated by CD4 dependent and independent mechanisms

The progressive loss of CD4 T lymphocytes is one of the hallmarks of HIV infection. The reverse correlation observed in vivo, between plasmatic HIV levels and CD4 T lymphocyte counts, supports the concept that direct HIV-mediated cell death contributes to this depletion. Previously, we and others have demonstrated, in vitro, that interactions between membrane-expressed HIV-envelope glycoprotein complexes and CD4 ecto-molecules are critical to cell killing which occurs mainly by apoptosis. Here, by the use of a co-culture model, in which chronically HIV-1 infected cells trigger apoptosis in uninfected CD4+ target cells, we have investigated the role of different CD4 domains in HIV envelope-mediated apoptosis. Target cells were A201 lymphoblastoid cell lines expressing wild-type CD4 or mutant forms of CD4. We show that the cytoplasmic domain of CD4 was not required for apoptosis induction. In contrast, the HIV permissive cell line expressing a CD4/CD8 chimeric molecule which contains only the first 171 amino acids of CD4, appeared to be resistant to HIV-induced apoptosis; thus suggesting that the D3-D4 CD4 module plays somewhat a regulatory role. Pre-treatment of wild-type CD4 expressing target cells by the phorbol ester PMA which leads to down-regulation of CD4, completely abolished apoptosis. Interestingly, in cells expressing CD4 devoid of its cytoplasmic domain, PMA blocked partially cell death without affecting, as expected, the CD4 expression. Taken together, these results demonstrate that although CD4 expression is essential for HIV envelope induced apoptosis, the apoptotic signal could be delivered in the absence of its cytoplasmic domain. Consistent with this, we suggest that other membrane associated molecule(s) are recruited for the signalling to initiate apoptosis.

The effect of size on trace metal levels in raft cultivated mussels (Mytilus galloprovincialis)

Mussels are farmed in the coastal inlets of Galicia by means of floating raft culture. The growth of these bivalves is due to their great capacity to filter the water column, which unfortunately, also exposes them to dangerous contaminants, including heavy metals. Thus, it is imperative that mussels be monitored for metals. Size has sometimes been shown to be an important variable, but contradictory results have been found. In order to monitor metals in raft mussels, it is necessary to compile information regarding the number of size classes according to shell length, which must be taken into account to obtain a representative sampling, as well as the number of sample replicates that must be included. Also, to be considered is the cost incurred by carrying out the collection, preparation and analysis per sample. The purpose of this study is to provide information about the effect of size, indicated by shell length on the metal content of raft mussels. The ability of 10 mussel-pooled samples to discriminate real differences in metal concentration was also studied. In general, a positive relationship between metal content and shell length was observed; a similar relation was found between the weight of soft tissues and shell length. As expected from the similarity encountered between relationships of metal content and dry weight-length, the concentrations of the different metals in the soft tissues would not seem to depend on the shell length. Metal concentrations, in this study, were found to be approximately 45 ppm of Hg, 0.5 ppm of Cd, 0.7 ppm of Pb, 0.5 ppm of Cr, 0.6 ppm of Ni, 8 ppm of As, 5 ppm of Cu and 122 ppm of Zn; on a dry weight basis. No significant differences between metal concentrations at different shell lengths were detected. Another important observation was the high variability observed within one size, indicating poor homogeneity in subgroups of similar size, which must be minimized if the number of samples is not enhanced as indicated by power and size analysis.

Serotypes, virulence genes, and intimin types of Shiga toxin (verotoxin)-producing Escherichia coli isolates from human patients: prevalence in Lugo, Spain, from 1992 through 1999

We have analyzed the prevalence of Shiga toxin-producing Escherichia coli (STEC) in stool specimens of patients with diarrhea or other gastrointestinal alterations from the Xeral-Calde Hospital of Lugo City (Spain). STEC strains were detected in 126 (2.5%) of 5,054 cases investigated, with a progressive increase in the incidence from 0% in 1992 to 4.4% in 1999. STEC O157:H7 was isolated in 24 cases (0.5%), whereas non-O157 STEC strains were isolated from 87 patients (1.7%). STEC strains were (after Salmonella and Campylobacter strains) the third most frequently recovered enteropathogenic bacteria. A total of 126 human STEC isolates were characterized in this study. PCR showed that 43 (34%) isolates carried stx(1) genes, 45 (36%) possessed stx(2) genes and 38 (30%) carried both stx(1) and stx(2). A total of 88 (70%) isolates carried an ehxA enterohemolysin gene, and 70 (56%) isolates possessed an eae intimin gene (27 isolates with type gamma1, 20 with type beta1, 8 with type zeta, 5 with type gamma2, and 3 with type epsilon). STEC isolates belonged to 41 O serogroups and 66 O:H serotypes, including 21 serotypes associated with hemolytic uremic syndrome and 30 new serotypes not previously reported among human STEC strains in other studies. Although the 126 STEC isolates belonged to 81 different seropathotypes (associations between serotypes and virulence genes), only four accounted for 31% of isolates. Seropathotype O157:H7 stx(1) stx(2) eae-gamma1 ehxA was the most common (13 isolates) followed by O157:H7 stx(2) eae-gamma1 ehxA (11 isolates), O26:H11 stx(1) eae-beta1 ehxA (11 isolates), and O111:H- stx(1) stx(2) eae-gamma2 ehxA (4 isolates). Our results suggest that STEC strains are a significant cause of human infections in Spain and confirm that in continental Europe, infections caused by STEC non-O157 strains are more common than those caused by O157:H7 isolates. The high prevalence of STEC strains (both O157:H7 and non-O157 strains) in human patients, and their association with serious complications, strongly supports the utilization of protocols for detection of all serotypes of STEC in Spanish clinical microbiology laboratories.

[BK virus in kidney allografts: a search for histologic evidence of the infection]

BACKGROUND

BK virus (BKV) associated interstitial nephritis is a complication in renal transplantation recipients. Its incidence is controversial. The aim of the present study is to determine the incidence of histopathologic evidence of BKV-infection in a single centre.

MATERIALS AND METHODS

Renal allograft tissue samples (n = 838) from 526 patients undergoing renal transplant were evaluated by light microscopy. Polymerase chain reaction (PCR) assay for BKV DNA was performed in 41 microdissected cell populations from cases with viral inclusions, cases with other nuclear changes, and cases without nuclear changes.

RESULTS

Polyomavirus-inclusions were identified in six cases (five with interstitial nephritis and other one with only urothelial infection). In one case with interstitial nephritis the DNA was degraded. PCR confirmed BKV infection in the other five and was negative in cases without inclusions.

CONCLUSIONS

Five patterns of inclusions bodies are observed and they appear to be characteristic. PCR assay seemingly have a high specificity for BKV detection and it does not usually detect latent viral infection.

[Non-Hodgkin lymphoma, IgA nephropathy and renal cell carcinoma]

Glomerular diseases could complicate lymphoid malignancies. We identified a patient with non-Hodgkin's lymphoma showing elevated levels of serum IgA1 paraprotein, renal infiltration by B cells, IgA nephropathy and renal cell carcinoma. It seems that there is a possible pathogenic relationship between these entities.

CXCR4 and SDF-1 expression in B-cell chronic lymphocytic leukemia and stage of the disease

The pathogenesis of B-cell chronic lymphocytic leukemia (B-CLL) has been linked to an overexpression of the chemokine receptor CXCR4 and increased in vitro functional response to its natural ligand CXCL12 (SDF-1). The CXCR4/SDF-1 system appears to be important for tissue localization and increased survival of B-CLL cells. The aim of our study was to examine if CXCR4 expression and SDF-1 blood levels were correlated to clinical and pathological stage of B-CLL. Flow cytometry and enzyme-linked immunosorbent assay (ELISA) techniques were used to determine CXCR4 expression and SDF-1 plasma levels, respectively, in a cohort of 51 patients diagnosed with B-CLL to correlate these measurements with several parameters that define the clinical stage of the disease. We confirmed that CXCR4 was consistently expressed on circulating B-CLL cells with a fluorescence intensity that was five-fold greater than in cells from healthy volunteers. There was a correlation between CXCR4 expression and leukocyte count ( r: 0.55, p<0.01), and CD19(+)/CD5(+ )cells ( r: 0.63, p<0.01). Interestingly, the group of B-CLL patients showed lower SDF-1 plasma levels compared to the control group. However, there was no correlation between CXCR4 or SDF-1 expression and the clinical stage of disease or the pattern of bone marrow infiltration. The results obtained suggest that other factors, and not only alteration in the SDF-1/CXCR4 chemokine system, must account for marrow infiltration of neoplastic cells observed in B-CLL and that CXCR4 could be involved in other features that exhibit malignant B cells, such as increased survival, rather than in their homing or migration to the bone marrow.

[Familial focal and segmentary hyalinosis]

Focal segmental glomerulosclerosis represents a finding in several renal disorders, characterized by proteinuria and sometimes by arterial hypertension and progressive decline in renal function. There are primary (idiopathic and familial) and secundary forms. In the last 20 years several familial cases has been reported, with a great genetic heterogeneity (dominant and recessive forms) and with multiple associations with particular MHC class-I and class-II gene loci, being Al, DR3 o DR7 the most frequently reported. We described three members of same family with focal segmental hyalinosis that shared the HLA haplotype A31 B61 DR13. This association has not been described previously. We highlight that genetic and acquired factors (obesity, hypertension...) could have importance in the development of progressive renal failure in these patients.

Application of the colloidal stability of TiO2 particles for recovery and reuse in solar photocatalysis

TiO2-catalyst suspensions work efficiently in photocatalysis for wastewater treatment. Nevertheless, once photocatalysis is complete, separation of the catalyst from solution becomes the main problem. Catalyst recovery has been enhanced through charge neutralisation and coagulation with electrolytes at lab and pilot-plant scale (40 L) to evaluate the potential for its separation after photocatalytic degradation of pollutants. Zeta-potential analysis showed that the isoelectric point (IEP) of TiO2 suspensions is near pH 7. Settling rates and hydrodynamic diameter of TiO2 particles are maximum at the IEP. However, suspensions are stable at different pH. TiO2 was reused in solar photocatalysis pilot-plant (40 L) for treatment of tetrachloroethylene (C2Cl4) comparing two procedures: reuse of the entire suspension after destruction of the organics without separation of the catalyst, and reuse of the catalyst after it had settled to the bottom and clear water had been removed. Photocatalytic efficiency worsens with successive runs when catalyst and water are reused without separation, whereas, when TiO2 is separated, the photocatalyst is not deactivated.

Loss of heterozygosity and methylation of p16 in renal cell carcinoma

To investigate the possible role of genomic aberrations of chromosome 9p21 in the tumorigenesis of human renal cell carcinoma (RCC), 40 sporadic RCCs were studied using PCR analyses. The tumours were predominantly low stage and low grade. Loss of heterozygosity (LOH) was observed in nine of 39 informative cases, but no homozygous deletion was noticed. Hypermethylation of the promoter region of p16 occurred in eight of the 40 RCCs. No correlation was found between hypermethylation of the p16 gene and LOH on 9p21. A similar level of LOH and methylation was observed in the 40 RCCS regardless of histology, grade and stage. These results suggest that inactivation of p16 and the possibility of other unknown tumour suppressor genes located on other chromosomes could be involved in the pathogenesis of RCC.

Prevalence and characterization of Vero cytotoxin-producing Escherichia coli isolated from diarrhoeic and healthy sheep and goats

Faecal samples from 146 diarrhoeic lambs and goat kids, and from 511 healthy sheep and goats were screened for the presence of Vero cytotoxin-producing Escherichia coli (VTEC). In healthy sheep and goats, VTEC were isolated in 24.4 and 16.2% of the animals, respectively. Moreover, VTEC were detected in 3.1 and 5.9% of the diarrhoeic lambs and goat kids, respectively. These data suggest that VTEC seems not to be associated with diarrhoea in lambs and goat kids. Only four VTEC strains were eae-positive. The absence of the eae gene in most of these VTEC strains could indicate that these strains are less virulent for humans that the classical eae-positive enterohaemorrhagic E. coli types. However, almost half (42.9%) and 12.2% of VTEC strains isolated from healthy sheep and goats, respectively, belonged to serotypes associated with severe diseases in humans.

Serotypes, virulence genes, and intimin types of Shiga toxin (verotoxin)-producing Escherichia coli isolates from healthy sheep in Spain

Fecal swabs obtained from 1,300 healthy lambs in 93 flocks in Spain in 1997 were examined for Shiga toxin-producing Escherichia coli (STEC). STEC O157:H7 strains were isolated from 5 (0.4%) animals in 4 flocks, and non-O157 STEC strains were isolated from 462 (36%) lambs in 63 flocks. A total of 384 ovine STEC strains were characterized in this study. PCR showed that 213 (55%) strains carried the stx(1) gene, 10 (3%) possessed the stx(2) gene, and 161 (42%) carried both the stx(1) and the stx(2) genes. Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 106 (28%) and 23 (6%) of the STEC strains, respectively. The STEC strains belonged to 35 O serogroups and 64 O:H serotypes (including 18 new serotypes). However, 72% were of 1 of the following 12 serotypes: O5:H-, O6:H10, O91:H-, O117:H-, O128:H-, O128:H2, O136:H20, O146:H8, O146:H21, O156:H-, O166:H28, and ONT:H21 (where NT is nontypeable). Although the 384 STEC strains belonged to 95 different seropathotypes (associations between serotypes and virulence genes), 49% of strains belonged to only 11. O91:H- stx(1) stx(2) (54 strains) was the most common seropathotype, followed by O128:H- stx(1) stx(2) (33 strains) and O6:H10 stx(1) (25 strains). Three strains of serotypes O26:H11, O156:H11, and OX177:H11 had intimin type beta1; 5 strains of serotype O157:H7 possessed intimin type gamma1; and 15 strains of serotypes O49:H-, O52:H12, O156:H- (12 strains), and O156:H25 had the new intimin, intimin type zeta. The majority (82%) of ovine STEC strains belonged to serotypes previously found to be associated with human STEC strains, and 51% belonged to serotypes associated with STEC strains isolated from patients with hemolytic-uremic syndrome. Thus, this study confirms that healthy sheep are a major reservoir of STEC strains pathogenic for humans.