The current status of zoonotic leishmaniases and approaches to disease control

Leishmaniases are a complex of world-wide diseases with a range of clinical and epidemiological features caused by Leishmania spp. of protozoan parasites. Among 15 well-recognised Leishmania species known to infect humans, 13 have zoonotic nature, which include agents of visceral, cutaneous and mucocutaneous forms of the disease in both the Old and New Worlds. Currently, leishmaniases show a wider geographic distribution and increased global incidence of human disease than previously known. Environmental, demographic and human behavioural factors contribute to the changing landscape of leishmaniasis, which includes increasing risk factors for zoonotic cutaneous leishmaniases and new scenarios associated with the zoonotic visceral leishmaniases. The latter consist of the northward spread of Leishmania infantum transmission in Europe and America, the identification of unusual mammal hosts, and the decline of HIV-Leishmania co-infections in southern Europe following the introduction of the highly active antiretroviral therapy. Few advances have been made in the surveillance and control of the zoonotic leishmaniasis, however a number of tools have been developed for the control of the canine reservoir of L. infantum. These include: (i) several canine vaccine candidates, in particular an FML Leishmania enriched fraction showing good clinical protection, has been registered in Brazil for veterinary use; (ii) a number of insecticide-based preparations have been specifically registered for dog protection against sand fly bites. Laboratory and field studies have shown improved efficacy of these preparations for both individual and mass protection.     

Role of interleukin-4 in regulation of age-related inflammatory changes in the hippocampus

It is well documented that long term potentiation (LTP) is impaired in the hippocampus of the aged animal. Among the changes that contribute to this impairment is an increase in hippocampal concentration of the pro-inflammatory cytokine interleukin-1beta (IL-1beta), and increased IL-1beta-induced signaling. In this study we investigated the possibility that these changes were a consequence of decreased concentration of the anti-inflammatory cytokine, IL-4, and decreased IL-4-stimulated signaling. We report that functional IL-4 receptors are expressed on granule cells of the dentate gyrus and that receptor activation results in phosphorylation of JAK1 and STAT6. Hippocampal IL-4 concentration was decreased with age, and this was accompanied by a decrease in phosphorylation of JAK1 and STAT6. The evidence indicates that IL-4 modulates expression of IL-1beta mRNA and protein and that it attenuates IL-1beta-induced impairment of LTP and phosphorylation of JNK and c-Jun. We argued that, if a decrease in hippocampal IL-4 concentration significantly contributed to the age-related impairment in LTP, then restoration of IL-4 should restore LTP. To test this, we treated rats with VP015 (phospholipid microparticles-incorporating phosphatidylserine), which increases IL-4 concentration in hippocampus. The data indicate that the VP015-induced increase in IL-4 concentration in hippocampus of aged rats and lipopolysaccharide (LPS)-treated rats was accompanied by a reversal of the age-related and LPS-induced impairment in LTP in perforant path granule cell synapses. We propose that interplay between pro-inflammatory and anti-inflammatory responses impact significantly on synaptic function in the hippocampus of the aged rat.     

Receptor fragment approach to the binding between CCK8 peptide and cholecystokinin receptors: a fluorescence study on type B receptor fragment CCK(B)-R (352-379)

Fluorescence titrations in a membrane mimetic solvent system allowed us to estimate that the dissociation constant of the bimolecular complex between CCK8 peptide and cholecystokinin type B receptor fragment CCK(B)-R (352-379) is in the micromolar range. When considered in the context of the full receptor/ligand model, these experiments demonstrate that the receptor fragment chosen on the basis of previous structural studies represents a reliable model system to monitor the ability of CCK8 or CCK8 analogs to bind the cholecystokinin receptor. Together with previous studies, this confirms that the receptor fragment approach adopted to define the binding mode of the CCK8 fragment of cholecystokinin with its two receptors, CCK(A) and CCK(B,) can be used to characterize the binding from the equilibrium standpoint. In this context, fluorescence spectroscopy proves to be the favored technique to measure dissociation constants in the nanomolar to micromolar range.     

Mutations in the "lid" region affect chain length specificity and thermostability of a Pseudomonas fragi lipase

The cold-adapted Pseudomonas fragi lipase (PFL) displays highest activity on short-chain triglyceride substrates and is rapidly inactivated at moderate temperature. Sequence and structure comparison with homologous lipases endowed with different substrate specificity and stability, pointed to three polar residues in the lid region, that were replaced with the amino acids conserved at equivalent positions in the reference lipases. Substitutions at residues T137 and T138 modified the lipase chain-length preference profile, increasing the relative activity towards C8 substrates. Moreover, mutations conferred to PFL higher temperature stability. On the other hand, replacement of the serine at position 141 by glycine destabilized the protein.     

Conventional Pap smear and liquid-based cytology as screening tools in low-resource settings in Latin America: experience of the Latin American screening study

OBJECTIVE: To evaluate the performance of the conventional Pap test and liquid-based cytology (LBC) in an ongoing multicenter trial testing optional screening tools (cytology, screening colposcopy, visual inspection with acetic acid, visual inspection with Lugol's Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, S?o Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina. STUDY DESIGN: A cohort of 12,107 women attending four clinics (Campinas, S?o Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive with any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance characteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10,240), and LBC (Autocyte PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n=320, and DNA-Citoliq [Digene Brazil], n =1,346) was performed by 1 of the clinics. RESULTS: Conventional Pap smears showed no squamous intraepithelial lesions (normal) in 8,946 (87.4%) and LBC in 1,373 (82.4%). Using high grade squamous intraepithelial lesions (HSIL) as the cutoff, Pap smears predicted high grade (cervical intraepithelial neoplasia [CIN] 3) with OR 63.0 (95% CI, 36.90-107.70), standard error (SE) 59%, SP 97.8%, positive predictive value (PPV) 68.1% and negative predictive value (NPV) 96.7%. The same figures for Autocyte PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NPV) 88.8%. DNA-Citoliq detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV 40.0% and NPV 94.6%. Lowering the cutoff to low grade squamous intraepithelial lesions increased SE and NPV but compromised SP and PPV. The detection rates for high grade lesions after an atypical squamous cells of undetermined significance diagnosis were similar with the 3 techniques. In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte PREP had 100% SP and PPV in detecting CIN3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCII.     

Additive inhibition of complement deposition by pneumolysin and PspA facilitates Streptococcus pneumoniae septicemia

Streptococcus pneumoniae is a common cause of septicemia in the immunocompetent host. To establish infection, S. pneumoniae has to overcome host innate immune responses, one component of which is the complement system. Using isogenic bacterial mutant strains and complement-deficient immune naive mice, we show that the S. pneumoniae virulence factor pneumolysin prevents complement deposition on S. pneumoniae, mainly through effects on the classical pathway. In addition, using a double pspA-/ply- mutant strain we demonstrate that pneumolysin and the S. pneumoniae surface protein PspA act in concert to affect both classical and alternative complement pathway activity. As a result, the virulence of the pspA-/ply- strain in models of both systemic and pulmonary infection is greatly attenuated in wild-type mice but not complement deficient mice. The sensitivity of the pspA-/ply- strain to complement was exploited to demonstrate that although early innate immunity to S. pneumoniae during pulmonary infection is partially complement-dependent, the main effect of complement is to prevent spread of S. pneumoniae from the lungs to the blood. These data suggest that inhibition of complement deposition on S. pneumoniae by pneumolysin and PspA is essential for S. pneumoniae to successfully cause septicemia. Targeting mechanisms of complement inhibition could be an effective therapeutic strategy for patients with septicemia due to S. pneumoniae or other bacterial pathogens.     

Birth and growth kinetics of brome mosaic virus microcrystals

The early steps of crystal nucleation and growth in Brome Mosa?c virus and polyethylene glycol mixtures were analyzed using time-resolved x-ray scattering (at the European Synchrotron Radiation Facility, Grenoble, France). The system was chosen as a crystallization model since the phase diagram of the macromolecule/polymer mixture was known to present, at high polymer concentration, a solid, precipitated phase made of the synchronized formation of a large number of microcrystals. The precipitation and crystallization of the samples was induced by the controlled mixing of virus and polymer using a stopped-flow device. Appearance and growth of Bragg diffraction peaks were used to follow the crystal nucleation and growth as a function of time, virus and polymer concentration, and polymer size. In all samples, the crystallization starts after a few seconds and proceeds for approximately 1-20 min until there is almost no virus left in the solution. The crystalline system was found to be face-centered cubic, with a unit cell size of 391 angstroms. The data analysis allowed us to show the presence of viruses in only two states, in solution or in crystals, revealing that the formation of periodic order proceeds without any detectable intermediate amorphous state.     

Blood soluble drag-reducing polymers prevent lethality from hemorrhagic shock in acute animal experiments

Over the past several decades, blood-soluble drag reducing polymers (DRPs) have been shown to significantly enhance hemodynamics in various animal models when added to blood at nanomolar concentrations. In the present study, the effects of the DRPs on blood circulation were tested in anesthetized rats exposed to acute hemorrhagic shock. The animals were acutely resuscitated either with a 2.5% dextran solution (Control) or using the same solution containing 0.0005% or 5 parts per million (ppm) concentration of one of two blood soluble DRPs: high molecular weight (MW=3500 kDa) polyethylene glycol (PEG-3500) or a DRP extracted from Aloe vera (AVP). An additional group of animals was resuscitated with 0.0075% (75 ppm) polyethylene glycol of molecular weight of 200 kDa (PEG-200), which possesses no drag-reducing ability. All of the animals were observed for two hours following the initiation of fluid resuscitation or until they expired. We found that infusion of the DRP solutions significantly improved tissue perfusion, tissue oxygenation, and two-hour survival rate, the latter from 19% (Control) and 14% (PEG-200) to 100% (AVP) and 100% (PEG-3500). Furthermore, the Control and PEG-200 animals that survived required three times more fluid to maintain their blood pressure than the AVP and PEG-3500 animals. Several hypotheses regarding the mechanisms underlying these observed beneficial hemodynamic effects of DRPs are discussed. Our findings suggest that the drag-reducing polymers warrant further investigation as a potential clinical treatment for hemorrhagic shock and possibly other microcirculatory disorders.     

The Neolithic transition in Europe and North Africa. The functional craneology contribution

The origin and mode of the process that led to food production in Europe and North Africa is a matter intensively discussed. It is not clear in the transition to the Neolithic in these regions if it results by a migration of peoples from the Near East, by changes in the behaviour of local populations, or by an interaction of both processes. Morphological changes in Europe and North Africa, from the Upper Palaeolithic to modern periods were assessed. A method based on the Functional Matrix Hypothesis was carried out, which implies that the bone shape is modified by the related soft tissues. Absolute and relative size and shape changes were estimated on two major--neural and facial--and eight minor--anteroneural, midneural, posteroneural, otic, optic, respiratory, masticatory and alveolar--functional cranial components (FCC). ANOVA and Canonical Correlation analyses indicate that neither a temporal trend nor a pattern characteristic of each region is evidenced. But a shift is observed between the Upper Palaeolithic groups and the later samples. Size is greater in the Upper Palaeolithics. Shape is modified because Upper Palaeolithics have greater midneural and masticatory FCCs, and smaller optic FCC. The greater masticatory volume is associated to wider faces in hunter-gatherers. Our study cannot enable to conclude if the morphological shift is caused by a replacement or by a change in the local populations, however, the morphological changes can be attributed to the reduced mobility and the masticatory stress since the Neolithic period.     

Mice lacking JunB are osteopenic due to cell-autonomous osteoblast and osteoclast defects

Because JunB is an essential gene for placentation, it was conditionally deleted in the embryo proper. JunBDelta/Delta mice are born viable, but develop severe low turnover osteopenia caused by apparent cell-autonomous osteoblast and osteoclast defects before a chronic myeloid leukemia-like disease. Although JunB was reported to be a negative regulator of cell proliferation, junBDelta/Delta osteoclast precursors and osteoblasts show reduced proliferation along with a differentiation defect in vivo and in vitro. Mutant osteoblasts express elevated p16(INK4a) levels, but exhibit decreased cyclin D1 and cyclin A expression. Runx2 is transiently increased during osteoblast differentiation in vitro, whereas mature osteoblast markers such as osteocalcin and bone sialoprotein are strongly reduced. To support a cell-autonomous function of JunB in osteoclasts, junB was inactivated specifically in the macrophage-osteoclast lineage. Mutant mice develop an osteopetrosis-like phenotype with increased bone mass and reduced numbers of osteoclasts. Thus, these data reveal a novel function of JunB as a positive regulator controlling primarily osteoblast as well as osteoclast activity.