Futility of abdominal drain in elective laparoscopic splenectomy.

PURPOSE: Despite the implementation of minimally invasive surgery and enhanced recovery protocols, the use of drain in elective splenectomy is still controversial. The aim of this study was to assess whether the abdominal drain can impact on short-term outcome after elective laparoscopic splenectomy. METHODS: This is a retrospective analysis of a consecutively collected database including all patients who underwent elective laparoscopic splenectomy in our institution between January 2001 and June 2019. Postoperative complications were defined according to a priori criteria and graded according to Clavien-Dindo classification. All complications that occurred during hospitalization or within 30 days after discharge were considered. Primary endpoint was postoperative morbidity, and secondary endpoint was postoperative hospital length of stay. RESULTS: One hundred and sixty-one patients were analysed. Intraperitoneal drain was placed in 75 (46.6%) patients. Postoperative complications occurred in 36 (22.4%) patients, while 8 (4.9%) patients had major complications. Median postoperative length of stay was 4 days. At multivariate analysis, only malignancy was significantly associated with the onset of complications (OR 3.50; 95% CI 1.1-11.0; p = 0.032). Malignancy, ASA > 2, conversion to open surgery, presence of drain and longer operation were significantly associated with prolonged length of stay. Patients with drain showed a greater unadjusted risk of abdominal collections (RR 10.32; 95% CI 1.3-79.6; p = 0.006). CONCLUSION: Abdominal drain did not reduce morbidity and prolonged the length of stay following elective laparoscopic splenectomy. Therefore, the present study does not support the routine use of drain in such procedure.

Valores energéticos de rações expandidas em diferentes temperaturas para frangos de corte / Energy values of expander feed in different temperatures for broilers

O objetivo deste estudo foi determinar os valores energéticos de rações expandidas, obtidas em diferentes temperaturas de expansão para frangos de corte em diferentes idades. As rações foram expandidas nas temperaturas: 80; 100; 120; 140ºC. Dois ensaios biológicos foram conduzidos utilizando-se o método tradicional de coleta total de excretas para determinar a energia metabolizável aparente corrigida (EMAn). Os ensaios metabólicos foram conduzidos com pintos machos Cobb, de 11 a 19 dias (fase inicial) e de 27 a 35 dias de idade (fase de crescimento), utilizando-se as mesmas aves do primeiro ensaio e, assim, preservando os tratamentos a que foram submetidas. Os valores da EMAn das rações da fase inicial foram: 2937; 2900; 2806 e 2751kcal/kg, e da fase de crescimento: 3045; 3031; 3115 e 2977kcal/kg, respectivamente. Os resultados mostraram uma redução linear dos níveis de EMn com o aumento da temperatura de expansão na idade de 11 a 19 dias. As perdas relativas entre as rações expandidas a 80 e 100ºC foram mínimas, enquanto nas temperaturas de 120 e 140ºC foram significativamente superiores. No ensaio de metabolismo para a fase de crescimento, verificou-se que as perdas relativas entre as rações expandidas a 80 e 100ºC foram pequenas (-14kcal). Para a ração expandida a 120ºC, o valor energético foi superior (84 kcal), enquanto para 140ºC foi significativamente inferior (-138kcal). Esses resultados mostram que, na fase de crescimento, os frangos de corte maximizaram o aproveitamento energético das rações na temperatura de expansão de 120ºC e que, em temperaturas acima desse nível, ocorrem altas perdas da EMAn das rações, que podem comprometer o consumo, a deposição de proteína e a conversão alimentar e, consequentemente, trazer grandes prejuízos econômicos pelo menos à idade de abate. As temperaturas de expansão de rações entre 80 e 100ºC apresentaram os melhores valores de EMAn para frangos com idade entre 15 e 10 dias, enquanto para idade de 31 a 35 dias foi de 120ºC.(AU)

The aim of this study was to determine the energetic value of feed in different expansion temperatures for broilers of different ages. The feedexpanded in the following temperatures: 80; 100, 120 and 140ºC. Two biological assays were run to establish apparent metabolizable energy corrected by nitrogen balance (AMEN) using the traditional total excreta collection method. In the first assay Cobb chicks were used from 11 to 19 days of age (initial period), and 29 to 37 days of age (growth period), as well as the same treatments of the first assay. The AMEN values for the initial period were respectively: 2937, 2900, 2806 and 2751 kcal/kg; and broilers in growing period were respectively: 3045, 3031, 3115 and 2977 kcal/kg. The results showed a linear decrease of the levels EMAN with an increase of the temperature of expansion from 11 to 19 days old. The loss relation between feed expanded at 80 and 100ºC were minimal, while in temperatures between 120 and 140ºC they were significantly higher. In the metabolic assay for period growth, we observed that the relation of energy values between feed expanded at 80 and 100ºC were smaller (14 kcal), while for the expanded in 120ºC they were superior (84 kcal), and at 140ºC were inferior (138 kcal). These results suggest greater energy utilization efficiency in period growth at a temperature of 120 ºC, while in temperatures above of this level there was greater loss of EMAN in feeds, which can prejudice feed intake, protein deposition and feed conversion, and consequently damage economics by increasing slaughter age. The expansion temperatures in feed between 80 and 100ºC showed the best EMAN values for broilers with 15 - 19 days of age, while for 31 - 35 days old it was 120 ºC.(AU)

CHK1 overexpression in T-cell acute lymphoblastic leukemia is essential for proliferation and survival by preventing excessive replication stress.

Checkpoint kinase 1 (CHK1) is a key component of the ATR (ataxia telangiectasia-mutated and Rad3-related)-dependent DNA damage response pathway that protect cells from replication stress, a cell intrinsic phenomenon enhanced by oncogenic transformation. Here, we show that CHK1 is overexpressed and hyperactivated in T-cell acute lymphoblastic leukemia (T-ALL). CHEK1 mRNA is highly abundant in patients of the proliferative T-ALL subgroup and leukemia cells exhibit constitutively elevated levels of the replication stress marker phospho-RPA32 and the DNA damage marker γH2AX. Importantly, pharmacologic inhibition of CHK1 using PF-004777736 or CHK1 short hairpin RNA-mediated silencing impairs T-ALL cell proliferation and viability. CHK1 inactivation results in the accumulation of cells with incompletely replicated DNA, ensuing DNA damage, ATM/CHK2 activation and subsequent ATM- and caspase-3-dependent apoptosis. In contrast to normal thymocytes, primary T-ALL cells are sensitive to therapeutic doses of PF-004777736, even in the presence of stromal or interleukin-7 survival signals. Moreover, CHK1 inhibition significantly delays in vivo growth of xenotransplanted T-ALL tumors. We conclude that CHK1 is critical for T-ALL proliferation and viability by downmodulating replication stress and preventing ATM/caspase-3-dependent cell death. Pharmacologic inhibition of CHK1 may be a promising therapeutic alternative for T-ALL treatment.

Valores nutricionais do milho de diferentes qualidades para frangas de reposição na fase de recria / Nutritional value of corn with different qualities for egg pullets in the growing phase

O experimento objetivou determinar os valores nutricionais de diferentes frações de milho obtidas por meio de estratificação em mesa densimétrica na recria de frangas. Os milhos foram designados como: MDA - milho de densidade alta; MDI - milho de densidade intermediária; MDB - milho de densidade baixa; MDT - milho de densidade total, composto de 30% de MDA, 60% de MDI e 10% de MDB. Para a determinação da energia metabolizável corrigida (EMAn) foi utilizado o método de coleta total de excretas em frangas Hy Line de 15 semanas. Os valores de EMAn (kcal/kg na MN) foram: 3.467; 3.340; 3.217 e 3.385kcal/kg e densidade (kg/m³): 818,61; 698,13; 681,80 e 736,39kg/m³ para MDA; MDI; MDB e MDT, respectivamente. O MDB apresentou maior valor em todos os aminoácidos digestíveis, com maior intensidade para o triptofano. As frações de milho foram variáveis quanto ao EMAn e perfil de aminoácidos digestíveis, indicando a necessidade de correções nutricionais para a formulação de rações de custo mínimo...

The experiment aimed to determine the nutritional value of different corn fractions obtained by stratification in a gravity table of replacement pullets. The corn was designated as MDA - high density corn; MDI - medium density corn; MDB - low density corn; MDT - total corn density, composed of 30% MDA, 60% MDI and 10% MDB. To determine the corrected metabolizable energy (AME N) a method for total collection of excreta with pullets Hy Line was used for 15 weeks. AME N (kcal/kg in MN) were: 3467, 3340, 3217 and 3385kcal/kg and density (kg/m³): 818.61, 698.13, 681.80 and 736.39 for MDA, MDI, MDB and MDT, respectively. The MDB showed the highest value in all the digestible amino acids, with higher intensity for the tryptophan. The fractions of corn were variable as to AME N and digestible amino acid profiles, indicating the need for corrections to the nutritional feed formulation of minimum cost...

Chest physical therapy for children hospitalised with acute pneumonia: a randomised controlled trial.

BACKGROUND: The indication for chest physical therapy as an adjunct to the treatment of children hospitalised with acute pneumonia remains controversial and there is a lack of robust scientific evidence for the effectiveness of this modality in these patients. METHODS: A randomised controlled trial was conducted in two tertiary hospitals in southern Brazil. Children aged 29 days to 12 years hospitalised with pneumonia between February and October 2006 were recruited; 51 were randomly allocated to the intervention group (chest physical therapy plus standard treatment for pneumonia) and 47 to the control group (standard treatment for pneumonia alone). The primary outcome was time to clinical resolution. The secondary outcomes were length of stay in hospital and duration of respiratory symptoms and signs. RESULTS: There were no significant differences in terms of median time to clinical resolution (4.0 vs 4.0 days, p = 0.84) and median length of hospital stay (6.0 vs 6.0 days, p = 0.76) between the intervention and control groups. The intervention group had a longer median duration of coughing (5.0 vs 4.0 days, p = 0.04) and of rhonchi on lung auscultation (2.0 vs 0.5 days, p = 0.03) than the control group. CONCLUSIONS: Chest physical therapy as an adjunct to standard treatment does not hasten clinical resolution of children hospitalised with acute pneumonia and may prolong duration of coughing and rhonchi.

Requirement for the cell division protein DivIB in polar cell division and engulfment during sporulation in Bacillus subtilis.

During spore formation in Bacillus subtilis, cell division occurs at the cell pole and is believed to require essentially the same division machinery as vegetative division. Intriguingly, although the cell division protein DivIB is not required for vegetative division at low temperatures, it is essential for efficient sporulation under these conditions. We show here that at low temperatures in the absence of DivIB, formation of the polar septum during sporulation is delayed and less efficient. Furthermore, the polar septa that are complete are abnormally thick, containing more peptidoglycan than a normal polar septum. These results show that DivIB is specifically required for the efficient and correct formation of a polar septum. This suggests that DivIB is required for the modification of sporulation septal peptidoglycan, raising the possibility that DivIB either regulates hydrolysis of polar septal peptidoglycan or is a hydrolase itself. We also show that, despite the significant number of completed polar septa that form in this mutant, it is unable to undergo engulfment. Instead, hydrolysis of the peptidoglycan within the polar septum, which occurs during the early stages of engulfment, is incomplete, producing a similar phenotype to that of mutants defective in the production of sporulation-specific septal peptidoglycan hydrolases. We propose a role for DivIB in sporulation-specific peptidoglycan remodelling or its regulation during polar septation and engulfment.

Membrane raft microdomains in chemokine receptor function.

Cell chemotaxis requires the acquisition and maintenance of both spatial and functional asymmetry between initially equivalent cell parts. In leukocytes one becomes the leading edge and the other, the rear edge or uropod. The acquisition of this cell polarity is controlled by an array of chemoattractants, including those of the chemokine family. We propose that chemokine receptor activation in highly organized lipid raft domains is a major determinant for the correct localization of the signaling pathways leading to the cell asymmetries required for migration. The lateral organization imposed by membrane raft microdomains is discussed in the context of other chemokine receptor activities, such as its role as a human immunodeficiency virus (HIV) coreceptor.

Improvement in affinity and HIV-1 neutralization by somatic mutation in the heavy chain first complementarity-determining region of antibodies triggered by HIV-1 infection.

We assessed the impact of somatic hypermutation in the framework region 1 (FR1) and complementarity-determining region 1 (CDR1) of three clonally-related heavy chains from the human monovalent antigen-binding fragments Fab S19, S8 and S20 on gp120 binding and HIV-1 neutralization capacity. Nucleotide changes were introduced in the heavy chains to revert single and multiple amino acid residues, and two Fab libraries were constructed with the same light chain to express equivalent amounts of parental and reverted phage Fab. We studied the contribution of each amino acid replacement to antigen binding by calculating the frequency of phage Fab retrieval after competitive library selection on gp120. Whereas mutations in FR1 had no effect on antigen binding, somatic replacements in the CDR1 of the heavy chain (HCDR1) appeared to produce significant changes. In S19 HCDR1, somatic mutation of residue 32 reduced gp120 binding. In Fab S20, the Arg(30) and Asp(31) somatically replaced residues in HCDR1 improved antigen binding. Both of these residues are necessary to increase Fab binding to gp120; reversion of either residue alone results in a decrease in binding. The impact of these two replacements was confirmed by the greater neutralization capacity of S20 compared to the other Fab. Molecular modeling of S20 HCDR1 suggests that Arg(30) and Asp(31) are the main interaction sites for gp120, increasing antibody affinity and promoting the enhanced neutralization ability of S20. These findings are consistent with a gp120-driven process, supporting a role for affinity maturation and intraclonal evolution of HIV-1 neutralizing antibodies.

Laparoscopic versus open splenectomy: a comparative study.

Laparoscopic splenectomy (LS) is gaining wide acceptance as a safe, effective alternative to open splenectomy (OS) in the treatment of hematologic disorders in adult and pediatric patients, with low conversion rates and complications. The aim of this retrospective case-control study was to compare two cohorts of patients, with similar characteristics, who underwent OS or LS in a single institution. The medical records of the initial 20 consecutive patients who underwent LS were reviewed and compared with a control group of 28 patients undergoing OS, matched for age, gender, diagnosis, splenic size and weight, and American Society of Anesthesiologists score. Data were collected regarding operative time, blood loss, blood transfusions, pathologic findings, accessory spleen detection, complications, ileus duration, and postoperative hospital stay. Nineteen patients underwent attempted LS. One procedure (5%) was converted to OS for uncontrolled hilar bleeding. Accessory spleens were detected in two cases in the LS group compared with four cases in the OS group (14%). Mean operative time was 165 minutes (range: 100-240 minutes) for LS and 114 minutes (75-180 minutes) for OS (P < 0.001). In the LS group a regular diet was tolerated 36 hours (range: 24-48 hours) after surgery compared with 72 hours (range: 48-96 hours) for the OS group (P < 0.001), and mean postoperative hospital stay was 4.1 days (range: 3-8 days) for LS, compared with 8.1 days (range: 5-12 days) for OS (P < 0.001). No differences were observed in blood loss, complication rates, or transfusion requirements. Compared with OS, LS requires more operative time (showing a learning curve), is comparable in blood loss, transfusion requirements, complication rates, and detection of accessory spleens and appears to be superior in terms of return of bowel function and hospital stay.

[The use of the biofragmentable ring (BAR-Valtrac) in colon surgery]. / Utilizzo dell'anello bioframmentabile (BAR-Valtrac) nella chirurgia colica.

BACKGROUND: Clinical results of colic anastomosis using biofragmentable anastomosis ring (BAR-Valtrac) are presented. Such a method showed to be a real alternative technique to the usual ones. METHODS: Eighty-six colic anastomosis using BAR are collected, 76 of which performed as elective surgery and 10 in emergency. The patients were 47 males and 39 females, with a mean age of 64 years. In 63 cases the patients were affected by colic neoplastic disease, in 16 by complicated diverticular disease (stenosis or perforation) and 7 patients had neoplastic disease of other organs involving the colon BAR device was used in 48 colic reconstructions after segmentary resection and in 38 colic reconstructions after left hemicolectomy. In each case 31-34 mm BAR were used. RESULTS: No perioperative death occurred in our series. Only one case (2%) of anastomotic leak was observed, while in 3 cases (4%) intestinal canalization disorders occurred. No problems for ring expulsion occurred in any patient. Three late complications were observed, as three cases of asymptomatic substenosis discovered during instrumental follow-up and spontaneously cleared up. CONCLUSIONS: On the basis of clinical results, and according to those reported in literature BAR anastomosis is considered a safe, feasible and easy technique to perform colic anastomosis, even in emergency, limited to the intraperitoneal tract of the colon.

HIV-1 infection through the CCR5 receptor is blocked by receptor dimerization.

The identification of the chemokine receptors as receptors for HIV-1 has boosted interest in these molecules, raising expectations for the development of new strategies to prevent HIV-1 infection. The discovery that chemokines block HIV-1 replication has focused attention on identifying their mechanism of action. Previous studies concluded that this inhibitory effect may be mediated by steric hindrance or by receptor down-regulation. We have identified a CCR5 receptor-specific mAb that neither competes with the chemokine for binding nor triggers signaling, as measured by Ca(2+) influx or chemotaxis. The antibody neither triggers receptor down-regulation nor interferes with the R5 JRFL viral strain gp120 binding to CCR5, but blocks HIV-1 replication in both in vitro assays using peripheral blood mononuclear cells as HIV-1 targets, as well as in vivo using human peripheral blood mononuclear cell-reconstituted SCID (severe combined immunodeficient) mice. Our evidence shows that the anti-CCR5 mAb efficiently prevents HIV-1 infection by inducing receptor dimerization. Chemokine receptor dimerization also is induced by chemokines and is required for their anti-HIV-1 activity. In addition to providing a molecular mechanism through which chemokines block HIV-1 infection, these results illustrate the prospects for developing new tools that possess HIV-1 suppressor activity, but lack the undesired inflammatory side effects of the chemokines.

Membrane raft microdomains mediate lateral assemblies required for HIV-1 infection.

HIV-1 infection triggers lateral membrane diffusion following interaction of the viral envelope with cell surface receptors. We show that these membrane changes are necessary for infection, as initial gp120-CD4 engagement leads to redistribution and clustering of membrane microdomains, enabling subsequent interaction of this complex with HIV-1 co-receptors. Disruption of cell membrane rafts by cholesterol depletion before viral exposure inhibits entry by both X4 and R5 strains of HIV-1, although viral replication in infected cells is unaffected by this treatment. This inhibitory effect is fully reversed by cholesterol replenishment of the cell membrane. These results indicate a general mechanism for HIV-1 envelope glycoprotein-mediated fusion by reorganization of membrane microdomains in the target cell, and offer new strategies for preventing HIV-1 infection.

Antibody repertoire against HIV-1 gp120 triggered in nude and normal mice by GM-CSF/gp120 immunization.

Granulocyte-macrophage colony stimulating factor (GM-CSF) facilitates the induction of primary immune responses by activating and recruiting antigen-presenting cells (APC), which efficiently present antigen determinants to Th cells. We have derived a functional GM-CSF/gp120 chimeric protein that, following immunization in soluble, adjuvant-independent form in normal mice, triggers highly specific, high affinity anti-gp120 antibodies. In contrast, nude mice respond with mutated, polyreactive, low affinity antibodies that mature further and increase in affinity in T cell-reconstituted nude mice. Anti-gp120 antibody production in nude mice is mediated principally by GM-CSF/gp120-triggered IL-4 production, since neutralizing anti-IL-4 abrogates the in vivo response. The anti-gp120 antibody response in normal, nude and T cell-reconstituted nude mice is encoded at a remarkably high frequency by the VH81X and VH7183 genes, a family used notably during fetal life and, when expressed at the adult stage, associated with autoimmune disease. We conclude that HIV gp120 binds and selects a subpopulation of developing B cells expressing a set of VH genes associated with immunodeficiency and autoimmunity.

Molecular analysis of HIV-1 gp120 antibody response using isotype IgM and IgG phage display libraries from a long-term non-progressor HIV-1-infected individual.

To characterize the variable heavy chain (VH)3 antibody response to HIV-1 gp120, we analyzed a panel of IgM and IgG1 Fab fragments from phage display isotype libraries from a long-term, non-progressor HIV-1-infected individual. The IgM Fab antibodies isolated had low affinity for gp120, were not restricted to a particular VH3 germ-line gene, and consisted mainly of unmutated VH genes. In contrast, IgG Fab fragments were gp120 specific, with high affinity and extensive somatic mutation; all were clonally related and were derived from a single VH3 germ-line gene (DP50). One IgG Fab (S8) has DP50 VH region nucleotide substitutions identical to those of IgM Fab M025 and uses similar DH and JH segments, suggesting that S8 arose from M025 by isotype switching. In addition, somatic mutation in the IgG heavy chain third complementarity-determining region results in a 100-fold affinity increase for gp120, which correlates with a similar increase in neutralization capacity. These results imply that in vivo IgM to IgG isotype switch and affinity maturation may be important for protection and long-term survival in certain HIV-1-infected individuals.

Natural human antibodies retrieved by phage display libraries from healthy donors: polyreactivity and recognition of human immunodeficiency virus type 1gp120 epitopes.

We have characterized the human natural antibody repertoire that contains antibodies recognizing the human immunodeficiency virus type 1 (HIV-1) gp120. A panel of monovalent antigen-binding fragments (Fab) selected from IgM and IgG isotype libraries generated from peripheral blood mononuclear cells (PBMC) of a healthy, HIV-1 noninfected individual was analysed, reflecting that only IgM, but not IgG, Fab were able to recognize HIV-1 gp120. The IgM Fab antibodies were not restricted to any particular heavy chain variable region (VH) germ line gene. However, the recognition of gp120 is associated to polyreactive antibodies and all display low-affinity interaction. This correlates with the absence of any maturation process as somatic mutation or isotype switch as the nucleotide sequence analysis of the variable regions reveals they are expressed near to germline configuration. In addition, none of the antibodies showed any neutralizing activity on HIV-1-infected lymphocytes, reflecting that the natural anti-gp120 repertoire is not sufficient to neutralize HIV infection.

A human immunodeficiency virus type 1 Env-granulocyte-macrophage colony-stimulating factor fusion protein enhances the cellular immune response to Env in a vaccinia virus-based vaccine.

Vaccinia virus (VV) infection induces protective T- and B-cell responses, making recombinants based on VV good candidates for the development of effective vaccines to other viruses. VV recombinants expressing the human immunodeficiency virus (HIV) envelope protein (Env) have been generated in several laboratories and shown to induce anti-HIV cellular and humoral immune responses in vaccinated humans and in chimpanzees. To increase the immunogenicity of the Env antigen, a VV recombinant was generated that expresses a chimeric antigen consisting of the Env protein fused to an immunostimulatory cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF). The chimeric protein retained GM-CSF biological activity when expressed by this recombinant virus (VV-GM-gp120) in cells infected in vitro. Infection of BALB/c mice with VV-GM-gp120 triggered a higher HIV-specific cellular immune response, as measured by interferon-gamma production, than that induced by a VV recombinant expressing the native Env protein. Moreover, although anti-gp120 antibody titres were similar in sera from mice inoculated with either of the VV recombinants, immunization with the recombinant expressing the fusion protein elicited antibodies against a broader spectrum of Env epitopes. These results indicate that HIV Env antigen fusion to GM-CSF provides a means to improve the anti-HIV immune response.

HIV-1 envelope protein gp120 triggers a Th2 response in mice that shifts to Th1 in the presence of human growth hormone.

Immunization of mice with HIV-1-gp120 results in predominant activation of the Th2 lymphocyte subset, leading to enhanced IL-4 production. Administration of human growth hormone at the time of gp120 immunization provokes a change in the cytokine production pattern, with lower IL-4 and higher gamma-IFN and IL-2 synthesis levels, indicating a preferential switch in stimulation from Th2 to Th1 cells. A growth hormone would thus be of great use for pharmacological intervention in those cases in which an infectious microorganism evades immune defenses by provoking a Th2 response. In addition, the ability of growth hormone to induce a Th1-type response upon vaccination with an HIV-antigen should be examined in the development of new therapeutic strategies or in the design of novel vaccines against HIV infection.

The chemokine monocyte chemotactic protein 1 triggers Janus kinase 2 activation and tyrosine phosphorylation of the CCR2B receptor.

The chemokines are a growing family of low m.w., 70- to 80-residue proinflammatory cytokines that operate by interacting with G protein-coupled receptors. Chemokines are involved in cell migration and in the activation of specific leukocyte subsets. Using the Mono Mac 1 monocytic cell line, we show that monocyte chemotactic protein 1 (MCP-1) triggers activation of the Janus kinase 2 (JAK2)/STAT3 pathway and CCR2 receptor tyrosine phosphorylation. Both Ca2+ mobilization and cell migration are blocked in Mono Mac 1 cells by tyrphostin B42, a specific JAK2 kinase inhibitor. Within seconds of MCP-1 activation, JAK2 phosphorylates CCR2 at the Tyr139 position and promotes JAK2/STAT3 complex association to the receptor. This MCP-1-initiated phosphorylation and association to JAK2 is also observed in CCR2B-transfected HEK293 cells. In contrast, when a CCR2B Tyr139Phe mutant is expressed in HEK293 cells, it is not phosphorylated in tyrosine and triggers neither JAK2/STAT3 activation nor Ca2+ mobilization in response to MCP-1. These results implicate the tyrosine kinase pathway in early chemokine signaling, suggesting a key role for this kinase in later events.

Suppression of HIV-1 infection in linomide-treated SCID-hu-PBL mice.

BACKGROUND: Proinflammatory cytokine overproduction, as well as synthesis of the inducible form of nitric oxide synthase (iNOS), are known to play a major role in HIV-1-triggered disease. AIDS patients show increased serum tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma levels, which synergize with HIV-1-produced nitric oxide (NO) to augment viral replication. Linomide has strong immunomodulatory effects in animals and humans, yielding promising clinical benefits in several pathological disorders including septic shock and autoimmune disease, processes largely mediated by overproduction of these cytokines. In peripheral T cells, linomide also prevents apoptosis triggered by a variety of stimuli, including superantigens, dexamethasone and vaccinia virus. DESIGN AND METHODS: Linomide inhibits production of proinflammatory cytokines such as TNF-alpha, interleukin-1 beta and IFN-gamma, as well as iNOS synthesis. The SCID-hu-PBL mouse model was used to analyse the effect of linomide on HIV-1 infection. T-cell frequency was characterized in reconstituted animals, and the frequency of infected mice and viral load of infected animals were studied. RESULTS: Linomide promotes an increase in human CD4+ T-cell counts in the peritoneal cavity of HIV-1-infected, linomide-treated mice. Linomide also prevents human TNF-alpha and IFN-gamma production, as well as iNOS expression and affects the viral load, promoting potent suppression of HIV-1 infectivity as detected in peritoneal cavity and spleen. CONCLUSIONS: The combination of linomide's properties, namely, blockage of proinflammatory cytokine and NO production, as well as prevention of apoptosis, is of paramount interest, making linomide a potential candidate for combating HIV-1 infection or preventing some of its associated pathological manifestations.