Functionalized bioadhesion-enhanced carboxymethyl cellulose/polyvinyl alcohol hybrid hydrogels for chronic wound dressing applications.

Wounds produced by trauma, burns, and chronic diseases cause millions of patients to suffer discomfort, pain, and, in many cases, disability and death, leading to enormous health, social and financial impacts globally. Regrettably, current clinical treatments for chronic wounds remain unsatisfactory. Thus, this study reports for the first time the design, development, and synthesis of chemically biofunctionalized hybrid hydrogels made of carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) crosslinked by citric acid using an entirely biocompatible and green process. They demonstrated suitable physicochemical properties, cytocompatibility, and hemocompatibility to be applied as a smart wound dressing for skin tissue engineering. These novel hybrids were biofunctionalized with l-arginine and RGD peptide through carbodiimide mediated-amide formation to promote bioadhesion of fibroblast and keratinocyte cells as a potential enhancement for wound healing and skin tissue engineering applications.

Evaluation of the immunomodulatory activity of thalidomide on tumor-associated macrophages in the 4T1 murine metastatic breast cancer model / [Avaliação do efeito imunomodulador da talidomida em macrófagos associados a tumores no modelo murino de câncer de mama metastático 4T1]

The present work evaluated the immunomodulatory effect of thalidomide (Thal) at different doses on tumor-associated macrophages (TAMs) using a mouse model of human breast cancer. Mice were inoculated with 4T1 cells in the left flank and treated with Thal once a day at concentrations of 50, 100, and 150mg/kg body weight from the 5th day until the 28th day of tumor inoculation. The tumors were sized, proliferation index and TAMs count were evaluated in primary tumors and metastatic lungs. In addition, the metastasis rate was evaluated in the lungs. Thal at 150mg/kg significantly decreased tumor growth, proliferation index, and TAMs infiltration in primary tumors. Conversely, a higher number of TAMs and lower proliferation index were observed in metastatic lungs in mice treated with 150mg/kg of Thal. Furthermore, Thal at 150mg/kg significantly decreased the metastatic nodules in the lungs. Our findings demonstrated that Thal treatment considerably decreased the primary tumor and lung metastasis in mice associated with different TAM infiltration effects in these sites.(AU)

No presente trabalho, foi avaliado o efeito imunomodulador de diferentes doses de talidomida em macrófagos associados ao tumor (TAMs), em um modelo murino de câncer de mama. Camundongos foram inoculados com células 4T1, na região do flanco esquerdo, e tratados com talidomida, uma vez ao dia, nas doses de 50, 100 e 150mg/k, por massa corporal, do quinto dia ao 28º dia de inoculação tumoral. Os tumores foram medidos, o índice de proliferação celular e a contagem de TAMs foram avaliados nos tumores primários e nos pulmões com metástases. Além disso, a taxa de metástases pulmonares também foi avaliada. A talidomida na dose de 150mg/kg diminuiu significativamente o crescimento tumoral, o índice de proliferação celular e a infiltração de TAMs nos tumores primários. Por outro lado, maior número de TAMs e menor índice de proliferação celular foram observados nos pulmões metastáticos, em camundongos tratados com 150mg/kg de talidomida. Ademais, a talidomida na dose de 150mg/kg diminuiu significativamente os nódulos metastáticos nos pulmões. Os resultados demonstraram que o tratamento com talidomida diminuiu o crescimento tumoral e as metástases pulmonares em camundongos, associado com diferentes efeitos na infiltração de TAMs nesses locais.(AU)

Extract from Arrabidaea chica (Fridericia chica) leaves show preventive action for the mitigation of doxorubicin-induced cardiotoxicity / [Extrato das folhas de Arrabidaea chica (Fridericia chica) mostrou potencial ação no combate à cardiotoxicidade induzida pela doxorrubicina]

A doxorrubicina (dox) é um medicamento antineoplásico que induz cardiotoxicidade por estresse oxidativo. Os flavonoides são antioxidantes extraídos de plantas como Camellia sinensis e Arrabidaea chica (Fridericia chica). Esta pesquisa objetivou avaliar efeitos protetores do extrato de A. chica (AC), comparado ao de C. sinensis (CS), frente ao estresse oxidativo induzido pela dox, no coração. Cardiomiócitos e células neoplásicas MDA-MB 231 foram incubados com AC e CS. Depois, adicionou-se dox e avaliaram-se taxas de viabilidade e morte celular. A citometria de fluxo para o ensaio de iodeto de propídeo (IP) em cardiomiócitos mostrou as seguintes taxas de morte celular: controle 53%; dox 78% (maior que controle, P=0,015); AC_12,5µg/mL + dox 65% (menor que dox, P=0,031); AC_25µg/mL + dox 62% (menor que dox, P=0,028); AC_50µg/mL + dox 63% (menor que dox, P=0,030); CS_12,5µg/mL + dox 71% (menor que dox, P=0,040); CS_25µg/ml + dox 69% (menor que dox, P=0,037); CS_50µg/mL + dox 74% (menor que dox, P=0,044). Resultados das células MDA-MB 231 mostraram que nenhum extrato interferiu na atividade antitumoral da dox. Os dados de IP foram corroborados pelos de MTT. Este estudo reporta promissora utilização de A. chica na prevenção da cardiotoxicidade induzida pela dox.(AU)

Liposomes co-encapsulating doxorubicin and glucoevatromonoside derivative induce synergic cytotoxic response against breast cancer cell lines.

Cancer is one of the main causes of death in the world and thus a global public health problem. Among the treatments available for cancer are surgery, radiotherapy, and chemotherapy. Currently, there is increased interest in the combination of two or more antitumor agents to achieve a synergistic effect in cancer therapy. Doxorubicin (DOX), a chemotherapeutic which has a potent antineoplastic action, has been used in the treatment of various tumors. However, the use of DOX is limited, mainly due to the cardiotoxicity. Therefore, nanostructured systems, such as liposomes, have been developed to carry this drug and target the tumor region, since tumor tissues present enhanced permeability and retention for nanosystems. Cardiac glycosides, such as digitoxin, have recently shown great antitumor potential despite the low therapeutic index which may limit their use. Furthermore, some compounds of this class have low water solubility, which makes their in vivo administration difficult. In this context, liposomes represent a valid strategy to carry simultaneously antitumor drugs allowing their intravenous administration. In this study, liposomes loaded with glucoevatromonoside containing peracetylated glucose hydroxyl groups (GEVPG) and DOX at molar ratio of 1:1 (SpHL-GEVPG:DOX 1:1) were developed, and their chemical and physicochemical properties were evaluated. This formulation presented a combination index (CI) lower than 1 at inhibitory concentration of 90 % growth (IC90) for three human breast tumor lines evaluated (0.52 ± 0.39 for MDA-MB-231, 0.19 ± 0.13 for MCF-7, and 0.99 ± 0.09 for SKBR-3). These results indicate a synergistic cytotoxic effect of the GEVPG and DOX combination encapsulated in liposomes. In addition, SpHL-GEVPG:DOX 1:1 presented selectivity towards these cancer cells. Long-term in vitro cytotoxicity studies demonstrated that MDA-MB-231 surviving cells after treatment with SpHL-GEVPG:DOX 1:1 did not recover proliferation capacity after 21 d. From the studies of cell cycle and death pathway evaluation, it was observed that SpHL-GEVPG:DOX 1:1 arrested the cell cycle in the G2/M phase and similarly induced apoptosis and necrosis. However, SpHL-GEVPG:DOX at molar ratio of 1:1 showed lower induction of both apoptotic and necrotic pathways compared to free DOX and SpHL-DOX, suggesting that the mechanism of death involved may not be related to necrosis or apoptosis. Lastly, SpHL-GEVPG:DOX 1:1 showed a good storage stability for 90 d at 4 °C. Therefore, the results of the present work indicate the potential use of SpHL-GEVPG:DOX 1:1 as a new anticancer formulation.

The DNA damage response is developmentally regulated in the African trypanosome.

Genomes are affected by a wide range of damage, which has resulted in the evolution of a number of widely conserved DNA repair pathways. Most of these repair reactions have been described in the African trypanosome Trypanosoma brucei, which is a genetically tractable eukaryotic microbe and important human and animal parasite, but little work has considered how the DNA damage response operates throughout the T. brucei life cycle. Using quantitative PCR we have assessed damage induction and repair in both the nuclear and mitochondrial genomes of the parasite. We show differing kinetics of repair for three forms of DNA damage, and dramatic differences in repair between replicative life cycle forms found in the testse fly midgut and the mammal. We find that mammal-infective T. brucei cells repair oxidative and crosslink-induced DNA damage more efficiently than tsetse-infective cells and, moreover, very distinct patterns of induction and repair of DNA alkylating damage in the two life cycle forms. We also reveal robust repair of DNA lesions in the highly unusual T. brucei mitochondrial genome (the kinetoplast). By examining mutants we show that nuclear alkylation damage is repaired by the concerted action of two repair pathways, and that Rad51 acts in kinetoplast repair. Finally, we correlate repair with cell cycle arrest and cell growth, revealing that induced DNA damage has strikingly differing effects on the two life cycle stages, with distinct timing of alkylation-induced cell cycle arrest and higher levels of damage induced death in mammal-infective cells. Our data reveal that T. brucei regulates the DNA damage response during its life cycle, a capacity that may be shared by many microbial pathogens that exist in variant environments during growth and transmission.

CLA-supplemented diet accelerates experimental colorectal cancer by inducing TGF-ß-producing macrophages and T cells.

Conjugated linoleic acid (CLA) has been shown to activate the nuclear receptor PPAR-γ and modulate metabolic and immune functions. Despite the worldwide use of CLA dietary supplementation, strong scientific evidence for its proposed beneficial actions are missing. We found that CLA-supplemented diet reduced mucosal damage and inflammatory infiltrate in the dextran sodium sulfate (DSS)-induced colitis model. Conditional deletion of PPAR-γ in macrophages from mice supplemented with CLA diet resulted in loss of this protective effect of CLA, suggesting a PPAR-γ-dependent mechanism mediated by macrophages. However, CLA supplementation significantly worsened colorectal tumor formation induced by azoxymethane and DSS by inducing macrophage and T-cell-producing TGF-ß via PPAR-γ activation. Accordingly, either macrophage-specific deletion of PPAR-γ or in vivo neutralization of latency-associated peptide (LAP, a membrane-bound TGF-ß)-expressing cells abrogated the protumorigenic effect of CLA. Thus, the anti-inflammatory properties of CLA are associated with prevention of colitis but also with development of colorectal cancer.

Neuroprotection and immunomodulation following intraspinal axotomy of motoneurons by treatment with adult mesenchymal stem cells.

BACKGROUND: Treatment of spinal cord injury is dependent on neuronal survival, appropriate synaptic circuit preservation, and inflammatory environment management. In this sense, mesenchymal stem cell (MSC) therapy is a promising tool that can reduce glial reaction and provide trophic factors to lesioned neurons. METHODS: Lewis adult female rats were submitted to a unilateral ventral funiculus cut at the spinal levels L4, L5, and L6. The animals were divided into the following groups: IA (intramedullary axotomy), IA + DMEM (Dulbecco's modified Eagle's medium), IA + FS (fibrin sealant), IA + MSC (106 cells), and IA + FS + MSC (106 cells). Seven days after injury, qPCR (n = 5) was performed to assess gene expression of VEGF, BDNF, iNOS2, arginase-1, TNF-α, IL-1ß, IL-6, IL-10, IL-4, IL-13, and TGF-ß. The cellular infiltrate at the lesion site was analyzed by hematoxylin-eosin (HE) staining and immunohistochemistry (IH) for Iba1 (microglia and macrophage marker) and arginase-1. Fourteen days after injury, spinal alpha motor neurons (MNs), evidenced by Nissl staining (n = 5), were counted. For the analysis of astrogliosis in spinal lamina IX and synaptic detachment around lesioned motor neurons (GAP-43-positive cells), anti-GFAP and anti-synaptophysin immunohistochemistry (n = 5) was performed, respectively. Twenty-eight days after IA, the gait of the animals was evaluated by the walking track test (CatWalk; n = 7). RESULTS: The site of injury displayed strong monocyte infiltration, containing arginase-1-expressing macrophages. The FS-treated group showed upregulation of iNOS2, arginase-1, proinflammatory cytokine (TNF-α and IL-1ß), and antiinflammatory cytokine (IL-10, IL-4, and IL-13) expression. Thus, FS enhanced early macrophage recruitment and proinflammatory cytokine expression, which accelerated inflammation. Rats treated with MSCs displayed high BDNF-positive immunolabeling, suggesting local delivery of this neurotrophin to lesioned motoneurons. This BDNF expression may have contributed to the increased neuronal survival and synapse preservation and decreased astrogliosis observed 14 days after injury. At 28 days after lesion, gait recovery was significantly improved in MSC-treated animals compared to that in the other groups. CONCLUSIONS: Overall, the present data demonstrate that MSC therapy is neuroprotective and, when associated with a FS, shifts the immune response to a proinflammatory profile.

BNNT/Fe3O4 System as an Efficient Tool for Magnetohyperthermia Therapy.

Nanostructured materials have been widely studied aiming to biomedical applications, primarily for the purpose of carrying drugs or molecules of interest in a selected tissue or organ. In this context, boron nitride nanotubes (BNNTs), when functionalized with specific moieties, could be useful as nanovectors for delivery of proteins, drugs, and also RNAi molecules, due to their capacity to be uptaked by cells. The introduction of magnetic nanoparticles allows the use of such system as a hyperthermia agent. Thus, once it has been targeted to tumor areas, it could kill cancer cells by magnetohyperthermia therapy. In order to study this effect, magnetite nanoparticles were incorporated into hydroxilated BNNT. The system was characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The results obtained show that magnetite nanoparticles are linked to the nanotubes. Magnetic measurements show that coercivity and magnetization were not disturbed after incorporation to the BNNT. Based on this, a new methodology for in vitro magnetohyperthermia experiments was developed, aiming to treat each cell group individually preserving its sterility. The biological assays of the system demonstrate its good cell viability and the great potential of this nanomaterial as a magnetohyperthermia agent for cancer treatment.

Tumour-associated macrophages: Relation with progression and invasiveness, and assessment of M1/M2 macrophages in canine mammary tumours.

Macrophages represent a major component of the overall leucocyte population within neoplasms and are important for tumour behaviour in several cancers in human beings. However, little information regarding their role in canine mammary tumours (CMTs) is available. The aim of this study was to address the potential role of tumour-associated macrophages (TAMs) in CMTs. TAMs in CMTs excised from 82 female dogs were quantified at high power (400× magnification) and categorised as low (≤50) or high (>50) TAM counts. Higher TAM counts were associated with clinical stage (P<0.001), tumour type (P=0.016), tumour size (P=0.013), vascular invasion (P=0.031), lymph node metastasis (P=0.003), high proliferation rates (P=0.009), vascular microdensity (P=0.008), invasive tumour profile (P=0.002) and worse prognosis (P=0.018; hazard ratio=0.283). Almost all macrophages infiltrating malignant tumours with high TAM counts expressed CD206 (macrophage mannose receptor 1), while all benign tumours were infiltrated by macrophages expressing inducible nitric oxide synthase (NOS2), suggesting a phenotypic shift from classically activated macrophage (M1) subpopulations towards alternatively activated macrophage (M2) subpopulations in malignant tumours. A triple staining pattern revealed mixed M1/M2 profiles in some tumours, thus characterising an intermediate state. The results indicate that TAMs are associated with more aggressive types of mammary cancer in dogs.

Cyclic adenosine monophosphate protects renal cell lines against amphotericin B toxicity in a PKA-independent manner.

Amphotericin B is the "gold standard" agent in the management of serious systemic fungal infections. However, this drug can cause nephrotoxicity, which contributes up to 25% of all acute kidney injuries in critically ill patients. Cyclic adenosine monophosphate can protect kidney cells from death due to injury or drug exposure in some cases. Hence, the objective of this work was to evaluate if cAMP could prevent cell death that occurs in renal cell lines subjected to AmB treatment and, if so, to assess the involvement of PKA in the transduction of this signal. Two different renal cell lines (LLC-PK1 and MDCK) were used in this study. MTT and flow cytometry assays showed increased cell survival when cells were exposed to cAMP in a PKA-independent manner, which was confirmed by western blot. This finding suggests that cAMP (db-cAMP) may prevent cell death caused by exposure to AmB. This is the first time this effect has been identified when renal cells are exposed to AmB's nephrotoxic potential.

The Relationship Between E-Cadherin and its Transcriptional Repressors in Spontaneously Arising Canine Invasive Micropapillary Mammary Carcinoma.

E-cadherin downregulation is related to metastatic behaviour and a poor prognosis in cancer. It might be induced by transcriptional repression mediated by the transcription factors SNAIL, ZEB1, ZEB2 and TWIST. Here, we investigated E-cadherin expression and its relationship to those transcriptional repressors (i.e. SNAIL, ZEB1, ZEB2 and TWIST) in the progression from carcinoma 'in situ' to invasion to lymph node metastasis in spontaneously arising canine invasive micropapillary carcinoma (IMPC). E-cadherin expression decreased from carcinoma in situ to invasive progression and was likely to increase with lymph node metastasis. Expression of SNAIL decreased from carcinoma in situ to invasive areas and from invasive areas to lymph nodes. Metastatic lymph nodes had higher expression of ZEB1 than carcinoma in situ and invasive areas. ZEB2 expression was observed in 52%, 38% and 33% of carcinoma in situ areas, invasive areas and lymph node metastases, respectively. TWIST expression was observed in 52%, 38% and 33% of carcinoma in situ areas, invasive areas and lymph node metastases, respectively. In invasive areas, E-cadherin downregulation correlated significantly with SNAIL and TWIST upregulation. Additionally, in infiltrating components of IMPCs, E-cadherin(-)SNAIL(+) neoplastic epithelial cells were observed by immunofluorescence. Taken together, canine mammary IMPCs had a loss of E-cadherin from carcinoma in situ to invasive areas, which appears to be induced by the transcription factor SNAIL. In lymph node metastasis, ZEB1 appears to not exert E-cadherin transcriptional repression activity.

Role of protein kinase A signaling pathway in cyclosporine nephrotoxicity.

Cyclosporine is an important immunosuppressive agent; however, nephrotoxicity is one of the main adverse effects. The purpose of this study was to evaluate the effect of inhibiting the protein kinase A (PKA) signaling pathway in nephrotoxicity caused by cyclosporine from the assessment of cell viability, pro-inflammatory cytokines, and nitric oxide (NO) production in LLC-PK1 and MDCK cell lines. Cyclosporine proved to be cytotoxic for both cell lines, as assessed by the mitochondrial enzyme activity assay (MTT), caused DNA fragmentation, determined by flow cytometry using the propidium iodide dye, and activated the PKA pathway (western blot assay). In MDCK cells, the inhibition of the PKA signaling pathway (H89 inhibitor) caused a significant reduction in DNA fragmentation. In both cell lines, the production of IL-6 proved to be a dependent PKA pathway, while TNF-α was not influenced by the inhibition of the PKA pathway. The NO production was increased when cells were pre-incubated with H89 followed by cyclosporine, and this production was dependent on the PKA pathway in LLC-PK1 and MDCK cells lines. Therefore, considering the present study's results, it can be concluded that the inhibition of PKA signaling pathway can aid in reducing the degree of nephrotoxicity caused by cyclosporine.

In vitro evaluation of Bifidobacterium strains of human origin for potential use in probiotic functional foods.

The present study investigated some in vitro properties for probiotic use of four strains of bifidobacteria isolated from faeces of healthy children (Bifidobacterium longum 51A, Bifidobacterium breve 1101A, Bifidobacterium pseudolongum 1191A and Bifidobacterium bifidum 1622A). In vitro tests were carried out to compare growth rate, aerotolerance, antagonistic activity against pathogens, antimicrobial susceptibility profile and cell wall hydrophobicity. Mean doubling time of B. longum 51A was shorter compared to the other strains. All strains were aerotolerant up to 72 h of exposure to oxygen. In vitro antagonism showed that B. longum 51A and B. pseudolongum 1191A were able to produce inhibitory diffusible compounds against all pathogenic bacteria tested, but not against Candida albicans. B. longum 51A was sensitive to all the antimicrobials tested, except neomycin. The hydrophobic property of the cell wall was highest for B. bifidum 1622A. Based on these parameters, B. longum 51A showed the best potential for probiotic use among the tested strains, presenting the greatest sensitivity to antimicrobials, the best growth rate and the highest capacity to produce antagonistic substances against various pathogenic microorganisms.

Atrial stretch increases the gastric tonus of anesthetized rats.

AIMS: We assessed the effects of right atrial stretch on gastric tone and neuro-humoral pathways involved in this phenomenon. MAIN METHODS: Anesthetized male rats were submitted for monitoring of the mean arterial pressure (MAP) and central venous pressure (CVP). A balloon catheter positioned into the stomach monitored by plethysmography the gastric volume (GV). All rats were monitored for 55-min. After the first 20-min of monitoring (basal period), rats were either submitted to a 5-min interval of atrial stretch (AS) or maintained as controls. An intra-atrial balloon catheter was distended with 30, 50, or 70 microL of saline. GV and hemodynamic data were also monitored for a further 30-min. Another set of rats, either previously submitted to subdiaphragmatic vagotomy or splanchnicectomy plus celiac ganglionectomy or maintained as controls (sham), were also submitted to AS. Each subset consisted of six rats. The plasma level of the atrial natriuretic peptide (ANP) was measured in another group of rats. Data were compared by ANOVA followed by Bonferroni's test. KEY FINDINGS: In control rats, the GV, MAP, and CVP remained at stable levels throughout the studies. In addition to increase the CVP, AS also decreased (P<0.05) the GV by 14%, 11.5%, and 16.5% in the 30, 50, and 70 microL groups, respectively. Vagotomy prevented the GV decrease. In contrast, the AS decreased (P<0.05) the GV by 21.3% in splanchnicectomized rats. SIGNIFICANCE: AS decreased the GV of rats in a volume-dependent manner, a phenomenon prevented by vagotomy but enhanced by celiac ganglionectomy.

Nuclear calcium signaling: a cell within a cell

Calcium (Ca2+) is a versatile second messenger that regulates a wide range of cellular functions. Although it is not established how a single second messenger coordinates diverse effects within a cell, there is increasing evidence that the spatial patterns of Ca2+ signals may determine their specificity. Ca2+ signaling patterns can vary in different regions of the cell and Ca2+ signals in nuclear and cytoplasmic compartments have been reported to occur independently. No general paradigm has been established yet to explain whether, how, or when Ca2+ signals are initiated within the nucleus or their function. Here we highlight that receptor tyrosine kinases rapidly translocate to the nucleus. Ca2+ signals that are induced by growth factors result from phosphatidylinositol 4,5-bisphosphate hydrolysis and inositol 1,4,5-trisphosphate formation within the nucleus rather than within the cytoplasm. This novel signaling mechanism may be responsible for growth factor effects on cell proliferation.

Nuclear calcium signaling: a cell within a cell.

Calcium (Ca2+) is a versatile second messenger that regulates a wide range of cellular functions. Although it is not established how a single second messenger coordinates diverse effects within a cell, there is increasing evidence that the spatial patterns of Ca2+ signals may determine their specificity. Ca2+ signaling patterns can vary in different regions of the cell and Ca2+ signals in nuclear and cytoplasmic compartments have been reported to occur independently. No general paradigm has been established yet to explain whether, how, or when Ca2+ signals are initiated within the nucleus or their function. Here we highlight that receptor tyrosine kinases rapidly translocate to the nucleus. Ca2+ signals that are induced by growth factors result from phosphatidylinositol 4,5-bisphosphate hydrolysis and inositol 1,4,5-trisphosphate formation within the nucleus rather than within the cytoplasm. This novel signaling mechanism may be responsible for growth factor effects on cell proliferation.

Comparison of antagonistic ability against enteropathogens by G+ and G- anaerobic dominant components of human fecal microbiota.

To confirm if anaerobic G+-components are those responsible for the function of colonization resistance, obligate anaerobic G+- and G- -bacteria from normal dominant microbiota of human feces were isolated from three successive collections and then used in in vitro assays for antagonism against two enteropathogenic bacteria. The production of inhibitory diffusible compounds was determined on supplemented BHI agar and MRS agar media for G- - and G+-bacteria, respectively. Salmonella enterica subsp. enterica serovar Typhimurium and Shigella sonnei were used as indicators. G+-bacteria presented a higher overall antagonistic frequency against both pathogenic bacteria (57 and 64 % for S. enterica serovar Typhimurium and S. sonnei, respectively) when compared to G+-microorganisms but with a quite elevated variation between volunteers (0-100 %) and collection samples (40-72 and 40-80 % for S. enterica sv. Typhimurium and S. sonnei, respectively). On the other hand, only three among 143 G- -isolates tested showed antagonistic activity. The results showed that, at least in vitro, obligate anaerobic G+-components of the dominant human fecal microbiota present a higher potential for antagonism against the enteropathogenic models tested than do G- -bacteria.

Nitrergic modulation of vasopressin, oxytocin and atrial natriuretic peptide secretion in response to sodium intake and hypertonic blood volume expansion.

The central nervous system plays an important role in the control of renal sodium excretion. We present here a brief review of physiologic regulation of hydromineral balance and discuss recent results from our laboratory that focus on the participation of nitrergic, vasopressinergic, and oxytocinergic systems in the regulation of water and sodium excretion under different salt intake and hypertonic blood volume expansion (BVE) conditions. High sodium intake induced a significant increase in nitric oxide synthase (NOS) activity in the medial basal hypothalamus and neural lobe, while a low sodium diet decreased NOS activity in the neural lobe, suggesting that central NOS is involved in the control of sodium balance. An increase in plasma concentrations in vasopressin (AVP), oxytocin (OT), atrial natriuretic peptide (ANP), and nitrate after hypertonic BVE was also demonstrated. The central inhibition of NOS by L-NAME caused a decrease in plasma AVP and no change in plasma OT or ANP levels after BVE. These data indicate that the increase in AVP release after hypertonic BVE depends on nitric oxide production. In contrast, the pattern of OT secretion was similar to that of ANP secretion, supporting the view that OT is a neuromodulator of ANP secretion during hypertonic BVE. Thus, neurohypophyseal hormones and ANP are secreted under hypertonic BVE in order to correct the changes induced in blood volume and osmolality, and the secretion of AVP in this particular situation depends on NOS activity.

Nitrergic modulation of vasopressin, oxytocin and atrial natriuretic peptide secretion in response to sodium intake and hypertonic blood volume expansion

The central nervous system plays an important role in the control of renal sodium excretion. We present here a brief review of physiologic regulation of hydromineral balance and discuss recent results from our laboratory that focus on the participation of nitrergic, vasopressinergic, and oxytocinergic systems in the regulation of water and sodium excretion under different salt intake and hypertonic blood volume expansion (BVE) conditions. High sodium intake induced a significant increase in nitric oxide synthase (NOS) activity in the medial basal hypothalamus and neural lobe, while a low sodium diet decreased NOS activity in the neural lobe, suggesting that central NOS is involved in the control of sodium balance. An increase in plasma concentrations in vasopressin (AVP), oxytocin (OT), atrial natriuretic peptide (ANP), and nitrate after hypertonic BVE was also demonstrated. The central inhibition of NOS by L-NAME caused a decrease in plasma AVP and no change in plasma OT or ANP levels after BVE. These data indicate that the increase in AVP release after hypertonic BVE depends on nitric oxide production. In contrast, the pattern of OT secretion was similar to that of ANP secretion, supporting the view that OT is a neuromodulator of ANP secretion during hypertonic BVE. Thus, neurohypophyseal hormones and ANP are secreted under hypertonic BVE in order to correct the changes induced in blood volume and osmolality, and the secretion of AVP in this particular situation depends on NOS activity

Protective effect of bifidus milk on the experimental infection with Salmonella enteritidis subsp. typhimurium in conventional and gnotobiotic mice.

The ability of Bifidobacterium bifidum from a commercial bifidus milk to antagonize Salmonella enteritidis subsp. typhimurium in vivo, and to reduce the pathological consequences for the host, was determined using conventional and gnotobiotic mice. Conventional animals received daily, by gavage, 0.1 ml bifidus milk containing about 10(9) cfu B. bifidum and germ-free animals received a single 0.1 ml dose. The conventional and gnotobiotic groups were challenged orally with 10(2) cfu of the pathogenic bacteria 5 and/or 10 d after the beginning of treatment. Control groups were treated with milk. Bifidus milk protected both animal models against the challenge with the pathogenic bacteria, as demonstrated by survival and histopathological data. However, to obtain the protective effect in gnotobiotic animals, the treatment had to be initiated 10 d before the challenge. In experimental and control gnotobiotic mice, Salm. enteritidis subsp. typhimurium became similarly established at levels ranging from 10(8) to 10(9) viable cells g-1 of faeces and remained at these high levels until the animals died or were sacrificed. It was concluded that the protection against Salm. enteritidis subsp. typhimurium observed in conventional and gnotobiotic mice treated with bifidus milk was not due to the reduction of the intestinal populations of the pathogenic bacteria.