HIV and mature dendritic cells: Trojan exosomes riding the Trojan horse?

Exosomes are secreted cellular vesicles that can induce specific CD4⁺ T cell responses in vivo when they interact with competent antigen-presenting cells like mature dendritic cells (mDCs). The Trojan exosome hypothesis proposes that retroviruses can take advantage of the cell-encoded intercellular vesicle traffic and exosome exchange pathway, moving between cells in the absence of fusion events in search of adequate target cells. Here, we discuss recent data supporting this hypothesis, which further explains how DCs can capture and internalize retroviruses like HIV-1 in the absence of fusion events, leading to the productive infection of interacting CD4⁺ T cells and contributing to viral spread through a mechanism known as trans-infection. We suggest that HIV-1 can exploit an exosome antigen-dissemination pathway intrinsic to mDCs, allowing viral internalization and final trans-infection of CD4⁺ T cells. In contrast to previous reports that focus on the ability of immature DCs to capture HIV in the mucosa, this review emphasizes the outstanding role that mature DCs could have promoting trans-infection in the lymph node, underscoring a new potential viral dissemination pathway.

Deletions and duplications of the 15q11-q13 region in spermatozoa from Prader-Willi syndrome fathers

Prader-Willi syndrome (PWS) is a genomic disorder mostly caused by deletions of 15q11-q13 region (70%). It has been suggested that the particular genomic architecture of 15q11-q13 region, characterized to be flanked by low copy repeats, could predispose it to Non-Allelic Homologous Recombination (NAHR). However, no studies in gametes of fathers of PWS individuals have been published to date. The objective of the study was to assess the incidence of 15q11-q13 deletions and duplications in spermatozoa from PWS fathers and to appraise the value of the data obtained for the estimation of the risk of recurrence for the syndrome. Semen samples from 16 fathers of PWS individuals and 10 control donors, were processed by triple-color fluorescence in situ hybridization. A customized combination of probes was used to discriminate between normal, deleted and duplicated sperm genotypes. A minimum of 10,000 sperm were scored for every single sample. A significant increase in the frequency of 15q11-q13 deletions and duplications were observed in PWS fathers (0.90 +/- 0.14%) compared with control donors (0.47 +/- 0.07%). Ten out of 16 individuals contributed to this population increase (P < 0.01), suggesting a predisposition for 15q11-q13 reorganizations. Statistical differences were observed in the frequency of 15q11-q13 deletions and duplications in fathers of PWS individuals (0.59 versus 0.31%; P = 0.001), indicating that intra-chromatid NAHR exchanges also substantially contribute to the rearrangements. Results demonstrated the increased susceptibility of some fathers of PWS individuals to generate 15q11-q13 deletions, suggesting that the screening of anomalies in sperm should be advisable as a valuable complement for genetic counseling.

On the steps of cell-to-cell HIV transmission between CD4 T cells

Although cell-to-cell HIV transmission was defined in early 90's, in the last five years, several groups have underscored the relevance of this mode of HIV spread between productively infected and uninfected CD4 T cells by defining the term virological synapse (VS). However, unraveling the molecular mechanisms of this efficient mode of viral spread appears to be more controversial than expected. Different authors have highlighted the role of a classical co-receptor-dependent HIV transmission while others describe a co-receptor-independent mechanism as predominant in VS. By analyzing different cellular models (primary cells and cell lines), we suggest that primary cells are highly sensitive to the physical passage of viral particles across the synapses, a co-receptor-independent phenomenon that we call "HIV transfer". Once viral particles are transferred, they can infect target cells by a co-receptor-dependent mechanism that fits with the classical meaning of "HIV transmission" and that is much more efficient in cell lines. Differences in the ability of primary CD4 T cells and cell lines to support HIV transfer and transmission explain most of the reported controversial data and should be taken into account when analyzing cell-to-cell HIV spread. Moreover, the terms transfer and transmission may be useful to define the events occurring at the VS. Thus, HIV particles would be transferred across synapses, while HIV infection would be transmitted between cells. Chronologically, HIV transfer is an early event occurring immediately after the VS formation, which precedes but does not inevitably lead to transmission, a late event resulting in infection.

[Role of decompressive craniectomy in brain injury patient]

Second level therapeutic maneuvres for controlling intracranial hypertension (ICH) proposed by the European Brain Injury Consortium and the American Association of Neurological Surgeons include barbiturates, moderate hypothermia and decompressive craniectomy (DC). However, neither barbiturates nor hypothermia have been demonstrated to improve its outcome. DC could be a therapeutic option in the management of ICH without intracerebral masses. Therefore, our goal has been to review and analyze the clinical usefulness of DC in patients with brain injury in an attempt to deal with some concerns of the critical care physicians. Can DC improve patient outcome? Currently, there are no randomized and controlled clinical trials supporting or rejecting the practice of DC in adults. Most published reports provide level II of evidence. However, most of those studies have shown that the outcome is better in patients with DC. When should DC be performed? It should be performed early to prevent ICH from occurring more than 12 hours. What are the effects of DC on intracranial pressure and brain oxygenation? In most patients, ICP can be maintained below 25 mmHg after a DC. However, to improve brain oxygenation (PtiO(2)), the probe must be placed in the healthy area of the most severely damaged cerebral hemisphere. What is the suggested surgical procedure? Frontal-subtemporal-parietal-occipital craniectomies, including enlargement of the dura by duroplasty. And finally, what are the current contraindications of DC? Glasgow Coma Scale score 3 points post-resuscitation states with dilated and arreactive pupils, age > 65 years old, ICH > 12 hours, persistent (a-yv)DO(2) < 3.2% or PtiO(2) < 10 mmHg maintained from the moment of admission.

Raised expression of cytokine receptor gp130 subunit on peripheral lymphocytes of patients with active lupus. A useful tool for monitoring the disease activity?

The glycoprotein gp130 is a signal traducing subunit with a membrane domain of the IL-6 receptor. In addition, gp130 is shared among the receptors for IL-6 superfamily, and it is critically involved in generating signal transduction through these receptors. The aim of the study is to evaluate the expression of the IL-6 superfamily receptor molecule gp130 on TCD4(+) and B cells in patients with systemic lupus erythematosus (SLE). Surface expression of gp130 on TCD4(+) and B lymphocytes was higher in patients with SLE than in healthy controls (2.79 vs 0.36% and 8.36 vs 0.37%, respectively). Patients with active lupus had higher expression of gp130 (relapsed 15.1%, new onset 26.6%) than stable patients (2.83%), in B-cell subset, but not in TCD4 lymphocytes. An important reduction in the gp130 expression on B lymphocytes was observed when the activity of the disease had disappeared after readjusting its immunosuppressive treatment (20.8-3.8%). In addition, there was significant correlation between the activity of the disease, measured like systemic lupus erythematosus disease activity index score, and surface expression of gp130 in lymphocytes B (r(s) = 0.5880, P = 0.0002). According with our results and roc curve analysis, a cut-off in 6.7% of B cells with gp130 expression were defined, who discriminates active/stable SLE with a sensitivity of 0.93 and a specificity of 0.75. In conclusion, there is an altered expression of gp130 in the patients with SLE. The disease activity as well as immunotherapy seems to influence the pattern of expression of gp130 on B-cell subsets in patients with SLE.

Human adipose tissue-derived mesenchymal stromal cells as vehicles for tumor bystander effect: a model based on bioluminescence imaging

Human adipose tissue mesenchymal stromal cells (AMSCs) share common traits, including similar differentiation potential and cell surface markers, with their bone marrow counterparts. Owing to their general availability, higher abundance and ease of isolation AMSCs may be convenient autologous delivery vehicles for localized tumor therapy. We demonstrate a model for tumor therapy development based on the use of AMSCs expressing renilla luciferase and thymidine kinase, as cellular vehicles for ganciclovir-mediated bystander killing of firefly luciferase expressing tumors, and noninvasive bioluminescence imaging to continuously monitor both, tumor cells and AMSCs. We show that the therapy delivering AMSCs survive long time within tumors, optimize the ratio of AMSCs to tumor cells for therapy, and asses the therapeutic effect in real time. Treatment of mice bearing prostate tumors plus therapeutic AMSCs with the prodrug ganciclovir induced bystander killing effect, reducing the number of tumor cells to 1.5 % that of control tumors. Thus, AMSCs could be useful vehicles to deliver localized therapy, with potential for clinical application in inoperable tumors and surgical borders after tumor resection. This approach, useful to evaluate efficiency of therapeutic models, should facilitate the selection of cell types, dosages, therapeutic agents and treatment protocols for cell-based therapies of specific tumors.

HIV-1 gp41 fusogenic function triggers autophagy in uninfected cells

Cell-expressed HIV-1 envelope glycoproteins (gp120 and gp41, called Env) induce autophagy in uninfected CD4 T cells, leading to their apoptosis, a mechanism most likely contributing to immunodeficiency. The presence of CD4 and CXCR4 on target cells is required for this process, but Env-induced autophagy is independent of CD4 signaling. Here we demonstrate that CXCR4-mediated signaling pathways are not directly involved in autophagy and cell death triggering. Indeed, cells stably expressing mutated forms of CXCR4, unable to transduce different Gi-dependent and -independent signals, still undergo autophagy and cell death after coculture with effector cells expressing Env. After gp120 binding to CD4 and CXCR4, the N terminus fusion peptide (FP) of gp41 is inserted into the target membrane, and gp41 adopts a trimeric extended pre-hairpin intermediate conformation, target of HIV fusion inhibitors such as T20 and C34, before formation of a stable six-helix bundle structure and cell-to-cell fusion. Interestingly, Env-mediated autophagy is triggered in both single cells (hemifusion) and syncytia (complete fusion), and prevented by T20 and C34. The gp41 fusion activity is responsible for Env-mediated autophagy since the Val2Glu mutation in the gp41 FP totally blocks this process. On the contrary, deletion of the C-terminal part of gp41 enhances Env-induced autophagy. These results underline the major role of gp41 in inducing autophagy in the uninfected cells and indicate that the entire process leading to HIV entry into target cells through binding of Env to its receptors, CD4 and CXCR4, is responsible for autophagy and death in the uninfected, bystander cells.

Raltegravir Susceptibility and Fitness Progression of HIV Type-1 Integrase in Patients on Long-Term Antiretroviral Therapy

Background

HIV type-1 (HIV-1) protease (PR), reverse transcriptase (RT) and integrase (IN) share the same precursor polyprotein and there is much evidence to suggest functional interactions between IN and RT. We aimed to elucidate whether long-term highly active antiretroviral therapy (HAART) targeting PR and RT could influence raltegravir susceptibility and the fitness of IN.

Methods

HIV-1 IN sequences from 45 heavily antiretroviral-experienced patients with longitudinal samples separated by a median of 10 years were obtained to estimate the rate of nucleotide substitution. IN recombinant viruses were generated from five selected patients. Phenotypic susceptibility to raltegravir was tested in vitro. Changes in viral replication capacity were assayed by growth kinetics and competition of intrapatient IN recombinant viruses.

Results

The amino acid substitution rate within IN was 0.06% per year during long-term antiretroviral treatment. Some substitutions had previously been associated with resistance to different IN inhibitors. Despite this, neither the early- nor late-derived IN recombinant viruses showed an increase in phenotypic susceptibility to raltegravir. Moreover, IN recombinant viruses corresponding to IN samples after 10 years of HAART had a replication capacity that was similar to or better than IN recombinant viruses from baseline samples.

Conclusions

HIV-1 IN from longitudinal samples taken from patients treated with IN inhibitor-sparing regimens showed no evidence of genotypic or phenotypic resistance to raltegravir. Additionally, long-term pressure with PR and RT inhibitors did not impair the fitness of HIV-1 IN. These data suggest that current antiretroviral regimens do not diminish the fitness of IN or influence raltegravir efficacy.

Detection of numerous verotoxigenic E. coli serotypes, with multiple antibiotic resistance from cattle faeces and soil

Verotoxigenic E. coli (VTEC) belong to a diverse range of serotypes. Serotypes O157 and O26 are predominately identified in VTEC-associated disease in Europe, however due to difficulty in detection little is known about the epidemiology of non-O157 serotypes. This study reports the identification of 7 VTEC serotypes from cattle faeces and soil. Cattle faeces samples (n=128) were taken from animals in 6 different farms, with soil samples (n=20) obtained from 1 farm. After sample incubation in modified tryptone soy broth (mTSB) supplemented with streptomycin sulphate samples were plated onto sorbitol MacConkey (SMAC) also supplemented with streptomycin sulphate. Bacteria detected on the plates were subjected to biochemical testing, antibiotic resistance profiling, and PCR to detect typical virulence genes, beta-lactamase and class 1 integron associated genes. Serotyping was performed on isolates positive for virulence genes. E. coli was identified from 103 samples, with verotoxin genes present in 7 E. coli isolates. Of these 7 isolates, 5 were resistant to 5 or more antibiotics. The isolate resistant to 9 antimicrobials contained a class 1 integron structure. Serotyping identified 7 separate VTEC, O2:H27, O26:H11, O63:H(-), O148:H8, O149:H1, O174:H21 and ONT:H25. Six of these VTEC have been previously associated with human disease, however with the exception of O26:H11, these serotypes have been rarely reported worldwide. Increased surveillance is required to determine the prevalence of these and other non-O157 VTEC. The presence of multi-antibiotic resistance in these isolates is of concern, and the overall implications for public health must be ascertained.

Association between mortality of Escherichia coli meningitis in young infants and non-virulent clonal groups of strains

To identify factors associated with Escherichia coli meningitis (ECM) mortality in infants aged <3 months, the clinical, biological and bacterial characteristics of isolates from 99 cases of ECM were compared, including the phylogenetic group, multilocus sequence type, O serogroup and sequence O type (a combination of sequence type complex (STc) and O serogroup) and virulence genotype. All 99 isolates were susceptible to the initial antimicrobial treatment. The mortality rate (14%) was not influenced by term or post-natal age. Hypotension or seizures were the sole clinical predictive factors for fatal outcome (p <0.01), and abnormal initial trans-fontanellar ultrasound was associated with death (p 0.03). Seventy-seven isolates belonged to the common sequence O types (STc29(O1), STc29(O18), STc29(O45), STc301(O7), STc304(O16), STc697(O83), STc700(O1)) causing neonatal meningitis. None of the phylogenetic groups and none of the virulence determinants were distributed differently between survivors and non-survivors, except that the aerobactin gene (iucC) was less frequent in lethal isolates (94% vs. 71%, p 0.02). Isolates belonging to rare sequence O types were more likely to be lethal (OR 4.3, p 0.01), although they induced a lower level of bacteraemia than common sequence O types such as STc29(O18) and STc29(O45) in a neonatal rat model. These results suggest that unidentified human genetic risk-factors may be more important than strain virulence in predicting ECM mortality.

A longitudinal study of verotoxin-producing Escherichia coli in two dairy goat herds

A longitudinal study was conducted on two dairy farms to investigate the pattern of shedding of verotoxin-producing Escherichia coli (VTEC) in goats. Faecal samples were taken from 20 goat kids once weekly during the first 4 weeks of life and then once every month for the next 5 months of life, and from 18 replacement animals and 15 adults once every month for 12 months. The proportion of samples containing VTEC was higher for replacement animals and adults (85.7% and 78.7%, respectively) than for goat kids (25.4%). About 90% of the VTEC colonies isolated from healthy goats belonged to five serogroups (O33, O76, O126, O146 and O166) but the most frequent serogroups of these isolates, except one, were different in the two herds studied. E. coli O157:H7 was found in three goat kids on only one occasion. None of the VTEC isolates, except the three E. coli O157:H7 isolates, was eae-positive. The patterns of shedding of VTEC in goat kids were variable, but, in contrast, most of the replacement animals and adults were persistent VTEC shedders. Our results show that isolates of VTEC O33, O76, O126, O146 and O166 are adapted for colonising the intestine of goats but that, in contrast, infection with VTEC O157:H7 in goats seems to be transient.

Subacute renal failure in diabetic nephropathy due to endocapillary glomerulonephritis and cholesterol embolization

Patients with established diabetic nephropathy could have other glomerular diseases superimposed on diabetic glomerulosclerosis. Cholesterol embolization syndrome (CES) is a systemic disorder caused by cholesterol crystal embolization from ulcerated atherosclerosis plaques in the aorta and its major branches. Curiously, there are few papers describing the association between diabetic nephropathy and CES. On the other hand, the clinical picture of CES resembles systemic vasculitis, and there is a controversy regarding the association between CES and glomerular or vascular inflammation. We report a case of atypical CES that developed after cardiac catheterization in a diabetic man; it presented as subacute renal failure with proliferative and exudative endocapillary glomerulonephritis.

[Indicators of quality in the critical patient]

The utility of using quality indicators as a tool to measure the common practice and evaluate efficacy of measures established to improve quality has been demonstrated, making it possible to identify and make known the improvements carried out. The project "Quality indicators in the critical patient" has been conducted by the Spanish Society of Intensive and Critical Medicine (SEMICYUC) under the methodological management of the Foundation Avedis Donabedian (FAD) of Barcelona. Its objective was to develop key indicators in the care of the critical patient, considering the following as added values: reaching an agreement on the quality criteria in these patients and providing the professionals with a potent and reliable instrument for clinical evaluation and management, introducing common evaluation methods that make it possible to unify the measure, making a comparative evaluation (benchmarking), having information that makes it possible to develop quality plans (quantitative, objective, reliable and valid data) and having a system that assures total quality of care to the critical patient.

[Ancillary studies in the differential diagnosis of epithelial renal cell tumors with granular cells]

INTRODUCTION AND OBJECTIVES

Differential diagnosis of renal neoplasms with granular cells may pose difficulties and implications on ontogeny and prognosis. Our aims are to characterize the pattern of immunostaining and to search for a useful diagnosis panel.

METHODS

We studied with colloidal iron staining (Mowry's modified method) and 22 commonly used immunomarkers 22 conventional carcinomas (CC), 37 chromophobe carcinomas (CPC), 8 oncocytomas (OC), and 7 collecting duct carcinomas (CDC) with granular cells. Cases with not entirely clear diagnosis were excluded.

RESULTS

Colloidal iron staining was diffuse, strong, reticular, and cytoplasmic in 32 CPC cases, the diffuse and strong pattern was not observed in other tumors. The more useful diagnostic panel was cytokeratin 7 (CK7)/CD10/vimentine (vim). The 8 OC were negative for the three antibodies. The most common profile for CC was CK7-/CD10+/vim+, the CPC profile was CK7+/CD10-/vim-, and CDC did not show a particular profile. With these three antibodies specificity was >90% for the differential diagnosis. Adding colloidal iron staining specificity was 100%.

CONCLUSIONS

Morphologic features, colloidal iron staining (modified Mowry's method), and immunostaining with CK7/CD10/vim permit the final diagnosis with high specificity. However, a 100% specific marker does not exist at the present time.

HIV transfer between CD4 T cells does not require LFA-1 binding to ICAM-1 and is governed by the interaction of HIV envelope glycoprotein with CD4

Background

Cell-to-cell HIV transmission requires cellular contacts that may be in part mediated by the integrin leukocyte function antigen (LFA)-1 and its ligands intercellular adhesion molecule (ICAM)-1, -2 and -3. The role of these molecules in free virus infection of CD4 T cells or in transinfection mediated by dendritic cells (DC) has been previously described. Here, we evaluate their role in viral transmission between different HIV producing cells and primary CD4 T cells.

Results

The formation of cellular conjugates and subsequent HIV transmission between productively infected MOLT cell lines and primary CD4 T cells was not inhibited by a panel of blocking antibodies against ICAM-1, ICAM-3 and α and β chains of LFA-1. Complete abrogation of HIV transmission and formation of cellular conjugates was only observed when gp120/CD4 interactions were blocked. The dispensable role of LFA-1 in HIV transmission was confirmed using non-lymphoid 293T cells, lacking the expression of adhesion molecules, as HIV producing cells. Moreover, HIV transmission between infected and uninfected primary CD4 T cells was abrogated by inhibitors of gp120 binding to CD4 but was not inhibited by blocking LFA-1 binding to ICAM-1 or ICAM-3. Rather, LFA-1 and ICAM-3 mAbs enhanced HIV transfer. All HIV producing cells (including 293T cells) transferred HIV particles more efficiently to memory than to naive CD4 T cells.

Conclusion

In contrast to other mechanisms of viral spread, HIV transmission between infected and uninfected T cells efficiently occurs in the absence of adhesion molecules. Thus, gp120/CD4 interactions are the main driving force of the formation of cellular contacts between infected and uninfected CD4 T cells whereby HIV transmission occurs.

Measurement of biofilm formation by clinical isolates of Escherichia coli is method-dependent

AIMS

In this study, we have evaluated the impact of methodological approaches in the determination of biofilm formation by four clinical isolates of Escherichia coli in static assays.

METHODS AND RESULTS

The assays were performed in microtitre plates with two minimal and two enriched broths, with one- or two-steps protocol, and using three different mathematical formulas to quantify adherent bacteria. Different biofilm formation patterns were found depending on the E. coli strain, culture medium and reading optical density on one- and two-steps protocol. Strong or moderate biofilm formation occurred mostly in minimal media. The mathematical formulas used to quantify biofilm formation also gave different results and bacterial growth rate should be taken into account to quantify biofilm.

CONCLUSIONS

Escherichia coli forms biofilms on static assays in a method-dependent fashion, depending on strain, and it is strongly modulated by culture conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

As verified in the studied E. coli strains, biofilm formation by any organism should be cautiously interpreted, considering all variables in the experimental settings.

Secondary amyloidosis associated with histiocytosis X

We report a 34-year-old man diagnosed with Langerhans cell histiocytosis (LCH) or histiocytosis X in 1980. He had multiple focal osseous lesions, difficult control of the disease activity and was treated many times with chemo- and radiotherapy for symptomatic control. His kidney disease started 20 years after the diagnosis with progressive renal failure and increasing non-nephrotic proteinuria, coinciding with two flares of LCH. A percutaneous renal biopsy demonstrated amyloidosis. There is only one case described in the amyloidosis literature associated with LCH.

Association between HIV replication and cholesterol in peripheral blood mononuclear cells in HIV-infected patients interrupting HAART

BACKGROUND

Cellular cholesterol is essential for HIV replication and may control HIV spread. HIV, in turn, appears to control cholesterol metabolism.

OBJECTIVES

To describe the relationships between serum lipids, cellular cholesterol and viral replication during highly active antiretroviral therapy (HAART) interruption.

METHODS

We have correlated virological parameters with the level of circulating lipids in serum and the content of cellular cholesterol in peripheral blood mononuclear cells (PBMCs). The study included 33 patients interrupting HAART with (n = 23) or without (n = 10) atorvastatin treatment.

RESULTS

Atorvastatin treatment did not modify PBMC cholesterol levels at week 4 after HAART interruption, although it significantly reduced serum cholesterol (total and LDL, where LDL stands for low density lipoprotein) (P < 0.05). Serum cholesterol or LDL marginally influenced PBMC cholesterol since no significant correlations were found between these parameters either at 0 or 4 weeks after HAART interruption. Analysis of virological data in all patients revealed a negative trend (P = 0.07) between baseline PBMC cholesterol and absolute CD4 T cell counts at baseline but a poor correlation (P = 0.18) with the viral load (VL) at week 4. Separate analysis of control patients showed a correlation between baseline PBMC cholesterol and VL at week 4 (P = 0.01). However, atorvastatin treatment abrogated this correlation by increasing viral replication in individuals with low cellular cholesterol.

CONCLUSIONS

Our data underscore the potential relevance of PBMC cholesterol in in vivo HIV replication and the complex effects of atorvastatin that seem to be unrelated to PBMC cholesterol.

Serotypes, virulence genes, intimin types and PFGE profiles of Escherichia coli isolated from piglets with diarrhoea in Slovakia

Two hundred and fifty Escherichia coli isolates from diarrhoeic and healthy piglets were serotyped and tested for the presence of virulence genes for fimbriae, intimin, heat-labile (LT) and heat-stable (STa and STb) enterotoxins, Stx toxins, and enteroaggregative heat-stable 1 (EAST1) enterotoxin by polymerase chain reaction (PCR). Although 220 isolates from diarrhoeic piglets belonged to 43 O serogroups and 77 O:H serotypes, 60% were of one of the 10 serogroups O2, O8, O15, O54, O84, O101, O141, O147, O149 and O157, and 60% belonged to only 10 serotypes (O8:H-, O54:H-, O84:H7, O101:H-, O141:H-, O141:H4, O147:H-, O149:H10, O163:H-, and ONT:H-). PCR showed that 79% of 220 isolates carried genes for at least one of the virulence factors tested. The gene encoding for EAST1 was the most prevalent (65%) followed by those encoding for STb (49%), LT (42%), STa (13%), and Stx2e (4%). Eighty-three (38%) of the 220 E. coli isolates carried the gene for F4 (K88), whereas genes for F18, F5 (K99), F41, F6 (P987), F17, and intimin (eae) were detected in 9%, 3%, 3%, 3%, 1%, and 3%, respectively. Seropathotype O149:H10:F4:LT/STb/EAST1 (70 isolates) was the most common, representing 32% of isolates. Pulsed-field gel electrophoresis (PFGE) analysis with XbaI of 15 O149:H10 representative isolates from diarrhoeic piglets distinguished 14 types. The 15 isolates exhibited a wide variability of distinct restriction patterns though all belonged to the same serotype (O149:H10), and all but one showed identical virulence determinants (F4, LT, STb, and EAST1). Among 30 isolates from healthy piglets only two virulence genes were detected: EAST1 (26%) and eae (17%). In total, 12 isolates were positives for the eae gene: five isolates had intimin beta1, four possessed intimin theta and three showed intimin type xiB. This is believed to be the first study describing the presence of intimin type xiB in E. coli of porcine origin.

Histologic Assessment of Donor Kidneys and Graft Outcome: Multivariate Analyses

We performed a multivariate analysis to evaluate the importance of histologic parameters in donor kidney biopsies as predictors of graft outcome.

METHODS

Wedge protocol biopsies from a single center were analyzed for glomerulosclerosis (GS), interstitial fibrosis (IF), tubular atrophy (TA), arteriosclerosis (AS), and arteriolar hyalinosis (AH). Alterations were quantified as percentage (GS, IF) or semiquantified according to Banff criteria (IF, TA, AS, AH). We calculated creatinine clearance (CrCl) at 1, 2, and 3 years posttransplant. Donor data included age, gender, and type: non-heart-beating donor or brain dead donors. Recipient data included age, gender, cold ischemia time, number of HLA mismatches, peak level of the panel reactive antibody (PRA), number of acute rejection episodes (ARE), and presence or absence of cytomegalovirus (CMV) disease. Univariate and multivariate analyses were performed. Follow-up range was 1 to 4.2 years.

RESULTS

GS, IF, TA, and AH were associated with graft survival in the multivariate analysis. The histologic parameters were associated with CrCl at several posttransplant time intervals, but the significance of association was lost in the multivariate analysis. Donor age showed a better correlation with graft function. In the univariate analyses adjusting for donor age, only IF and AH were associated with graft function.

CONCLUSIONS

Histologic parameters showed a modest association with graft function. In our study, donor age is the better predictor of graft function. IF and AH may be similar to or better than GS as predictors of graft outcome.

Maturation of blood-derived dendritic cells enhances human immunodeficiency virus type 1 capture and transmission

Dendritic cells (DCs) are specialized antigen-presenting cells. However, DCs exposed to human immunodeficiency virus type 1 (HIV-1) are also able to transmit a vigorous cytopathic infection to CD4(+) T cells, a process that has been frequently related to the ability of DC-SIGN to bind HIV-1 envelope glycoproteins. The maturation of DCs can increase the efficiency of HIV-1 transmission through trans infection. We aimed to comparatively study the effect of maturation in monocyte-derived DCs (MDDCs) and blood-derived myeloid DCs during the HIV-1 capture process. In vitro capture and transmission of envelope-pseudotyped HIV-1 and its homologous replication-competent virus to susceptible target cells were assessed by p24(gag) detection, luciferase activity, and both confocal and electron microscopy. Maturation of MDDCs or myeloid DCs enhanced the active capture of HIV-1 in a DC-SIGN- and viral envelope glycoprotein-independent manner, increasing the life span of trapped virus. Moreover, higher viral transmission of mature DCs to CD4(+) T cells was highly dependent on active viral capture, a process mediated through cholesterol-enriched domains. Mature DCs concentrated captured virus in a single large vesicle staining for CD81 and CD63 tetraspanins, while immature DCs lacked these structures, suggesting different intracellular trafficking processes. These observations help to explain the greater ability of mature DCs to transfer HIV-1 to T lymphocytes, a process that can potentially contribute to the viral dissemination at lymph nodes in vivo, where viral replication takes place and there is a continuous interaction between susceptible T cells and mature DCs.

Role of sperm FISH studies in the genetic reproductive advice of structural reorganization carriers

The use of fluorescence in-situ hybridization (FISH) in decondensed spermatozoa from carriers of structural chromosomal abnormalities provides a way to estimate the amount of unbalanced products. This methodology has become a tool of special interest for a better approximation of the reproductive competence of the carriers. Although there is no discussion regarding the cytogenetic value of the information obtained, the usefulness of performing individual sperm FISH studies must be weighed depending on the object of the study. In this paper, we introduce some considerations concerning the convenience of a routine application of sperm FISH analysis in the major populations of structural reorganization carriers. For each group, the significance of the information that can be obtained and its relevance for genetic reproductive advice are discussed.

Serotypes, virulence genes, and intimin types of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) isolated from calves in São Paulo, Brazil

Shiga toxin-producing Escherichia coli (STEC), is the most important recently emerged group of foodborne pathogens. Ruminants, especially cattle, have been implicated as a principal reservoir of STEC, undercooked ground beef and raw milk being the major vehicles of foodborne outbreaks. Enteropathogenic E. coli (EPEC) strains are defined as eae-harboring diarrheagenic E. coli that possess the ability to form A/E lesions on intestinal cells and that do not possess Shiga toxin genes. In order to determine the occurrence, serotypes and virulence markers of STEC and EPEC strains, 546 fecal samples from 264 diarrheic calves and 282 healthy calves in beef farms in São Paulo, Brazil, were screened by PCR. STEC and EPEC were isolated in 10% and 2.7% of the 546 animals, respectively. Although IMS test was used, the STEC serotype O157:H7 was not detected. The most frequent serotypes among STEC strains were O7:H10, O22:H16, O111:H(-), O119:H(-) and O174:H21, whereas O26:H11, O123:H11 and O177:H11 were the most prevalent among EPEC strains. In this study, serotypes not previously reported were found among STEC strains: O7:H7, O7:H10, O48:H7, O111:H19, O123:H2, O132:H51, O173:H(-), and O175:H49. The eae gene was detected in 25% of the STEC and 100% of EPEC strains. The intimin type theta/gamma2 was the most frequent among STEC, whereas the intimin beta1 was the most frequent intimin type among EPEC strains. To our knowledge, this is the first report of the occurrence of the new intimin muB in one strain of animal origin. This new intimin was detected in one atypical EPEC strain of serotype O123:H? isolated from diarrheic cattle. The enterohemolysin (ehxA) was detected in 51% of the STEC and 80% of the EPEC strains, whereas STEC autoagglutinating adhesin (saa) virulence gene was detected only in those STEC strains negative for eae gene. All 15 bovine EPEC strains isolated in this study were negative for both eaf and bfp genes. Our data shows that in Brazil cattle are not only a reservoir of STEC and atypical EPEC, but also a potential source of infection in humans, since the important STEC serotypes previously described and associated with severe diseases in humans, such as O111:H(-), O113:H21, O118:H16, and O174:H21 were isolated.

[Lupus nephritis and hypothyroidism]

Thyroid diseases could be associated with several renal alterations. In the present report we describe a patient with SLE with inactive renal involvement and symptomatic hypothyroidism that developed a clinical picture similar to lupus flare.

Treatment of monocytes with interleukin (IL)-12 plus IL-18 stimulates survival, differentiation and the production of CXC chemokine ligands (CXCL)8, CXCL9 and CXCL10

During inflammation, interleukin (IL)-12 and IL-18 are produced by macrophages and other cell types such as neutrophils (IL-12), keratinocytes and damaged endothelial cells (IL-18). To explore the role of IL-12 and IL-18 in inflammatory innate immune responses we investigated their impact on human peripheral blood monocytes and mature bronchoalveolar lavage (BAL) macrophages. IL-12 and IL-18 together, but not alone, prevented spontaneous apoptosis of cultured monocytes, promoted monocyte clustering and subsequent differentiation into macrophages. These morphological changes were accompanied by increased secretion of CXC chemokine ligands (CXCL)9, CXCL10 (up to 100-fold, P < 0.001) and CXCL8 (up to 10-fold, P < 0.001) but not CCL3, CCL4 or CCL5. Mature macrophages (from BALs) expressed high basal levels of CXCL8, that were no modified upon stimulation with IL-12 and IL-18. In contrast, the basal production of CXCL9 and CXCL10 by BALs was increased by 10-fold (P < 0.001) in the presence of either IL-12 or IL-18 alone and by 50-fold in the presence of both cytokines. In conclusion, our results indicate a relevant role for IL-12 and IL-18 in the activation and resolution of inflammatory immune responses, by increasing the survival of monocytes and by inducing the production of chemokines. In particular, those that may regulate angiogenesis and promote the recruitment of monocytes, activated T cells (CXCL9 and CXCL10) and granulocytes (CXCL8).

[Immunohistochemical profile and clinical features of mucinous tubular and spindle renal cell carcinoma]

INTRODUCTION

We present the immunohistochemical (IHC) analyses of a series of four kidney tumors currently classified as mucinous tubular and spindle renal cell carcinoma (WHO), a tumor with uncertain histogenesis and differentiation. Our aims were to determine an immunoprofile and to add clinical and morphological information about this rare renal carcinoma.

MATERIAL AND METHODS

The four tumors were found between 415 renal carcinomas at our center (0.89%). IHC was carried out with a panel of antibodies in these four cases. Morphogical and clinical information was collected and analyzed.

RESULTS

All tumors were well circumscribed and confined to the kidney. Immunoreactivity for cytokeratin (CK)7 was intense and diffuse. Immunostaining was variable for EMA, vimentin, S-100, Ulex europaeus antigen, high-molecular-weight CK, CK 8, CK18, and CK 19. The tumors were homogeneously negative for CEA, CD15, CD10, CD34, desmin, actin, CK10, CK20, and HMB45. Proliferative index (Ki67) was <1% en all cases. The immunoreactivity was similar in cuboidal and spindle cells.

CONCLUSIONS

The present tumor shows a variable immunophenotype and there is not a precise cell type differentiation. The immunostaining in cuboidal and spindle cells suggests a similar differentiation and histogenesis.

Neuroprotection by GDNF-secreting stem cells in a Huntington's disease model: optical neuroimage tracking of brain-grafted cells

The use of stem cells for reconstructive or neuroprotective strategies can benefit from new advances in neuroimaging techniques to track grafted cells. In the present work, we analyze the potential of a neural stem cell (NSC) line, which stably expresses the glial cell line-derived neurotrophic factor (GDNF) and the firefly luciferase gene (GDNF/Luc-NSC), for cell therapy in a Huntington's disease mouse model. Our results show that detection of light photons is an effective method to quantify the proliferation rate and to characterize the migration pathways of transplanted NSCs. Intravenous administration of luciferine, the luciferase substract, into the grafted animals allowed the detection of implanted cells in real time by an optical neuroimaging methodology, overpassing the limits of serial histological analyses. We observed that transplanted GDNF/Luc-NSCs survive after grafting and expand more when transplanted in quinolinate-lesioned nude mouse striata than when transplanted in non-lesioned mice. We also demonstrate that GDNF/Luc-NSCs prevent the degeneration of striatal neurons in the excitotoxic mouse model of Huntington's disease and reduce the amphetamine-induced rotational behavior in mice bearing unilateral lesions.