Low-Level Fluoride Exposure Increases Insulin Sensitivity in Experimental Diabetes.

The effect of chronic fluoride (F) exposure from the drinking water on parameters related to glucose homeostasis was investigated. Wistar rats were randomly distributed into 2 groups (diabetic [D] and nondiabetic [ND]; n = 54 each). In D, diabetes was induced with streptozotocin. Each group was further divided into 3 subgroups (0, 10, or 50 mgF/L in drinking water). After 22 days of treatment, plasma and liver samples were collected. No alterations in glycemia, insulinemia, K(ITT), and HOMA2-IR (homeostasis model assessment 2 of insulin resistance) were seen for ND. F-exposure of D rats led to significantly lower insulinemia, without alterations in glycemia (increased %S). Proteomic analysis detected 19, 39, and 16 proteins differentially expressed for the comparisons D0 vs. D10, D0 vs. D50, and D10 vs. D50, respectively. Gene Ontology with the most significant terms in the comparisons D0 vs. D10, D0 vs. D50, and D50 vs. D10 were organic acid metabolic process and carboxylic acid metabolic process, organic acid metabolic process, and cellular ketone metabolic process. Analysis of subnetworks revealed that proteins with fold changes interacted with GLUT4 in comparison D0 vs. D10. Among these proteins, ERj3p was present in D10. Upregulation of this protein in the presence of F might help to explain the higher %S found in these animals. These data suggest that fluoride might enhance glucose homeostasis in diabetes and identify specific biological mechanisms that merit future studies.

A model for selective ion adsorption including van der Waals interaction.

A model for the selective adsorption phenomenon in an isotropic liquid accounting for a van der Waals interaction between the ions and the surface is presented, in the framework of the Poisson-Boltzmann theory. The fundamental equations governing the electric field distribution are exactly solved for low and high potential regimes.

Destabilizing effect of a surface electric field generated by ionic adsorption on the molecular orientation of nematic liquid crystals.

The destabilizing effect of a surface electric field, produced by selective ionic adsorption, on the molecular orientation of a nematic-liquid-crystal sample is analyzed for a cell in the shape of a slab of thickness d. The electric-field distribution considered in the analysis is the one obtained in the limit in which essentially all the positive ions are adsorbed. Because of the coupling of this surface field with the nematic director, the surface anchoring energy depends on the thickness of the sample as well as on the adsorption energy characterizing the surfaces. A relation connecting the threshold field for the destabilization of the homeotropic pattern to the adsorption energy and to the thickness of the sample is established in closed form, after solving a set of two coupled non-linear equations determining the electric-field distribution across the sample. It is shown that the values of surface electric field generated by adsorbed ions that can lead to a destabilization of the homeotropic alignment can be attained by real samples.

Contribution of the ionic adsorption phenomenon to the effective anchoring energy of a nematic liquid-crystal sample.

The effective anchoring energy resulting from the ionic adsorption phenomenon in a nematic liquid-crystal sample in the shape of a slab of thickness d is investigated. The electric field distribution is determined in the framework of a general nonlinear Poisson-Boltzmann approach. The analysis is particularized for the case in which d>>lambdaD, where lambdaD is the Debye screening length. In this limit, the spatially dependent electric field distribution across the sample as well as the contribution, of dielectric and flexoelectric origins, to the effective anchoring energy is obtained in an exact manner.

Immunomodulatory properties of Alternanthera tenella Colla aqueous extracts in mice

Plants from the genus Alternanthera are thought to possess antimicrobial and antiviral properties. In Brazilian folk medicine, the aqueous extract of A. tenella Colla is used for its anti-inflammatory activity. The present study investigated the immunomodulatory property of A. tenella extract by evaluating the antibody production in male albino Swiss mice weighing 20-25 g (10 per group). The animals received standard laboratory diet and water ad libitum. The effect of A. tenella extract (5 and 50 mg/kg, ip) was evaluated in mice immunized with sheep red blood cells (SRBC 10 percent, ip) as T-dependent antigen, or in mice stimulated with mitogens (10 æg, Escherichia coli lipopolysaccharide, LPS, ip). The same doses (5 and 50 mg/kg, ip) of A. tenella extract were also tested for antitumor activity, using the Ehrlich ascites carcinoma as model. The results showed that 50 mg/kg A. tenella extract ip significantly enhanced IgM (64 percent) and IgG2a (50 percent) antibody production in mice treated with LPS mitogen. The same dose had no effect on IgM-specific response, whereas the 5 mg/kg treatment caused a statiscally significant reduction of anti-SRBC IgM-specific antibodies (82 percent). The aqueous extract of A. tenella (50 mg/kg) increased the life span (from 16 ± 1 to 25 ± 1 days) and decreased the number of viable tumor cells (59 percent) in mice with Ehrlich ascites carcinoma. The present findings are significant for the development of alternative, inexpensive and perhaps even safer strategies for cancer treatment

Immunomodulatory properties of Alternanthera tenella Colla aqueous extracts in mice.

Plants from the genus Alternanthera are thought to possess antimicrobial and antiviral properties. In Brazilian folk medicine, the aqueous extract of A. tenella Colla is used for its anti-inflammatory activity. The present study investigated the immunomodulatory property of A. tenella extract by evaluating the antibody production in male albino Swiss mice weighing 20-25 g (10 per group). The animals received standard laboratory diet and water ad libitum. The effect of A. tenella extract (5 and 50 mg/kg, ip) was evaluated in mice immunized with sheep red blood cells (SRBC 10%, ip) as T-dependent antigen, or in mice stimulated with mitogens (10 micro g, Escherichia coli lipopolysaccharide, LPS, ip). The same doses (5 and 50 mg/kg, ip) of A. tenella extract were also tested for antitumor activity, using the Ehrlich ascites carcinoma as model. The results showed that 50 mg/kg A. tenella extract ip significantly enhanced IgM (64%) and IgG2a (50%) antibody production in mice treated with LPS mitogen. The same dose had no effect on IgM-specific response, whereas the 5 mg/kg treatment caused a statiscally significant reduction of anti-SRBC IgM-specific antibodies (82%). The aqueous extract of A. tenella (50 mg/kg) increased the life span (from 16 +/- 1 to 25 +/- 1 days) and decreased the number of viable tumor cells (59%) in mice with Ehrlich ascites carcinoma. The present findings are significant for the development of alternative, inexpensive and perhaps even safer strategies for cancer treatment.

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities.

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

African-derived mitochondria in South American native cattle breeds (Bos taurus): evidence of a new taurine mitochondrial lineage.

This article reports the nucleotide diversity within the control region of 42 mitochondrial chromosomes belonging to five South American native cattle breeds (Bos taurus). Analysis of these data in conjunction with B. taurus and B. indicus sequences from Africa, Europe, the Near East, India, and Japan allowed the recognition of eight new mitochondrial haplotypes and their relative positions in a phylogenetic network. The structure of genetic variation among different hypothetical groupings was tested through the molecular variance decomposition, which was best explained by haplotype group components. Haplotypes surveyed were classified as European-related and African-related. Unexpectedly, two haplotypes within the African cluster were more divergent from the African consensus than the latter from the European consensus. A neighbor-joining tree shows the position of two haplotypes compared to European/African mitochondrial lineage splitting. This different and putatively ancestral mitochondrial lineage (AA) is supported by the calibration of sequence divergence based on the Bos-Bison separation. The European/African mitochondria divergence might be subsequent (67,100 years before present) to that between AA and Africans (84,700 years before present), also preceding domestication times. These genetic data could reflect the haplotype distribution of Iberian cattle five centuries ago.

Cationic antimicrobial protein of Mr 37 kDa: a multifunctional inflammatory protein.

PURPOSE: To investigate the role of cationic antimicrobial protein of Mr 37 kDa (CAP37) a neutrophil-derived inflammatory mediator on endothelial cell function. DATA SOURCES: Endothelial cells used in this study were obtained from human lung microvessels and rat aorta. The latter was a kind gift of Dr. Paula Grammas. The mono-mac 6 cell line used in this study was the generous gift of Dr. H.W. Loms Ziegler-Heitbrock. STUDY SELECTION AND DATA EXTRACTION: Endothelial cell proteins kinase C activity was determined by measuring calcium- and phospholipid-dependent phosphorylation of histone. Endothelial cell migration was determined using Costar Transwell apparatus. Cell surface expression of adhesion molecules, ICAM-1 and PECAM-1 was determined using flow cytometry. RT-PCR was used to amplify the CAP37 from endothelial cells treated with LPS. RESULTS: We demonstrated that CAP37 which was originally identified as having potent antimicrobial activity and chemotactic activity for monocytes was capable of modulating endothelial cell functions. CAP37 activated endothelial cell protein kinase C in a dose- and time-dependent fashion. Importantly CAP37 increased the adhesive properties of the endothelium for monocytes. CAP37 upregulated the well known adhesion molecules, ICAM-1 and PECAM-1 in a dose- and time-dependent manner. In addition, CAP37 promoted endothelial cell migration. Further investigations indicated that CAP37 was induced in endothelial cells in response to pro-inflammatory cytokines such as tumor necrosis factor-alpha and interleukin-1 alpha as well as inflammatory mediators such as lipopolysaccharide. Unstimulated endothelial cells did not constitutively express CAP37. The cDNA sequence of endothelial CAP37 was determined and found to be highly homologous to the sequence obtained for neutrophil-derived CAP37. CONCLUSIONS: Our studies strongly suggest that CAP37 plays a pivotal role in monocyte-endothelial interactions and the transmigration of monocytes from the vasculature into extravascular tissues.

Interaction of a synthetic peptide based on the neutrophil-derived antimicrobial protein CAP37 with dipalmitoyl-phosphatidylcholine membranes.

CAP37, a cationic antimicrobial protein of Mr 37 kDa is constitutively expressed in human neutrophils. A synthetic peptide, CAP37 P20-44, corresponding to amino acid residues 20 through 44 of the native CAP37 molecule has been shown to mimic the antimicrobial activity of the native protein. An analog of peptide CAP37 P20-44 was synthesized in which the cysteine residues at positions 26 and 42 were replaced with serine residues (CAP37 P20-44Ser). This resulted in a peptide that no longer exhibited bactericidal activity. The effect of different concentrations of the active CAP37 peptide, CAP37 P20-44, and its inactive analog, CAP37 P20-44Ser, on artificial lipid membranes composed of dipalmitoyl phosphatidylcholine (DPPC) was studied using small-angle X-ray scattering and differential scanning calorimetry. The results indicated that CAP37 P20-44 perturbs the periodicity of the lamellar structure as shown by small angle X-ray diffraction, while the effect of the inactive peptide is not as strong. Differential scanning calorimetry further confirms that CAP37 P20-44 interacts with lipid membranes as indicated by increased width of the transition and decreased peak height. Moreover, it completely abolishes the pretransition temperature of the DPPC membranes. The effect of the inactive peptide, CAP37 P20-44Ser on the thermotropic properties of DPPC was small. These studies suggest that CAP37 perturbs the lamellar structure of lipid bilayers and further suggests that the antibiotic action of the molecule may be through its interactions with the lipid components of the Gram negative bacterial membrane.

A synthetic lipopolysaccharide-binding peptide based on the neutrophil-derived protein CAP37 prevents endotoxin-induced responses in conscious rats.

The lipid A component of lipopolysaccharide (LPS) derived from Escherichia coli has been implicated as a significant mediator in the development of circulatory and metabolic dysfunction and lethality associated with sepsis. A synthetic peptide corresponding to amino acid residues 20 through 44 of the neutrophil-derived 37-kDa cationic antimicrobial protein (CAP37 P(20-44)) possesses lipid A binding characteristics which may be useful in attenuating in vivo responses induced during circumstances of endotoxemia, including sepsis. The E. coli LPS to be used in the in vivo study was shown to be attenuated by CAP37 P(20-44) in a dose-dependent manner in the in vitro reaction with Limulus amoebocyte lysate. Intravenous infusion of CAP37 P(20-44) (1.5 or 3.0 mg/kg of body weight) with E. coli LPS (250 microg/kg over 30 min) into conscious, unrestrained rats prevented LPS-induced hyperdynamic and hypodynamic circulatory shock, hyperlactacidemia, and leukopenia in a dose-related fashion. CAP37 P(20-44) (0.2, 1.0, and 5.0 mg/kg) administered intravenously to conscious, actinomycin D-sensitized rats following a lethal dose of LPS neutralized LPS toxicity, resulting in dose-dependent 7-day survival rates of 30, 50, and 80%, respectively. CAP37 P(20-44) (5.0 mg/kg) significantly inhibited the endotoxin-induced increase in circulating tumor necrosis factor alpha in sensitized rats. These data demonstrate that CAP37 P(20-44) has the capacity to abolish in vivo biological responses to LPS that are relevant to human sepsis and to significantly neutralize the toxicity of circulating E. coli LPS.

Expression of CAP37, a novel inflammatory mediator, in Alzheimer's disease.

Recent evidence suggests that inflammation in the central nervous system plays an important role in the pathogenesis of Alzheimer's disease. However, the identity of the inflammatory mediators, cytokines, and reactive oxygen species, that orchestrate cell death and plaque biogenesis in Alzheimer's disease, have yet to be elucidated. We have identified a novel inflammatory mediator, CAP37 (Cationic Antimicrobial Protein Mi 37 kDa), that promotes mononuclear cell chemotaxis, adhesion of monocytes to endothelium, and release of oxygen radicals from monocytes. In the present immunocytochemical study, we demonstrate the expression of CAP37 in the cerebral microvasculature in Alzheimer's disease. CAP37 was not detected in brain vessels of normal controls or patients with other neuropathologic conditions such as Pick's, Parkinson's, Binswanger's disease, Progressive Supranuclear Palsy, and Candida infection. Treatment of cerebral endothelial cultures with inflammatory mediators, cytokines or beta-amyloid results in the induction of CAP37 expression. These in vitro data showing endothelial-CAP37 expression after beta-amyloid treatment together with the previous demonstration that CAP37 stimulates mononuclear cell migration and activation, suggest that CAP37 could contribute to neuronal injury in Alzheimer's disease.

CAP37, a neutrophil granule-derived protein stimulates protein kinase C activity in endothelial cells.

CAP37 is a multifunctional protein isolated from human neutrophils with important implications in host defense and inflammation. It is antimicrobial, mediates monocyte chemotaxis, and binds endotoxin. The interaction of neutrophils with endothelial cells is a central feature in inflammation. The object of this study was to determine whether CAP37, a neutrophil-derived protein, could regulate vascular endothelial cell protein kinase C (PKC), an important signaling enzyme. We found that CAP37 stimulated endothelial PKC activity in both a time- and dose-dependent fashion. This stimulation was comparable in magnitude to that evoked by phorbol myristate acetate. A monospecific antiserum against CAP37 inhibited CAP37-induced PKC activity. To establish a structural basis for this activity, overlapping peptides, based on the sequence of native CAP37 were synthesized. Maximum PKC stimulation was evoked by a peptide corresponding to amino acids 95-122 of native CAP37. This domain was distinct from the antibiotic and endotoxin binding domain of the molecule, which resides between amino acids 20 and 44. These data demonstrate that CAP37 can alter endothelial cell PKC and suggest that CAP37 may play a role in neutrophil-endothelial interactions.

Sperm immobilizing activity of a synthetic bioactive peptide 20-44 of 37-kDa cationic antimicrobial protein (CAP37) of human neutrophils.

We have previously reported that human sperm coincubated with human peripheral blood neutrophils in the presence of complement (C)-fixing antisperm antibody (ASA)-positive sera are rapidly internalized and degraded within the neutrophil phagolysosome. However, the mechanism by which motile sperm are processed within the phagolysosome is unknown. Various spermicidal/antimicrobial proteins contained in azurophilic granules that can be secreted into the phagolysosome may play a role in sperm disposal. In this study, we examined the expression of a 37-kDa cationic antimicrobial protein (CAP37) during sperm phagocytosis and the effect of its synthetic bioactive fragment, Peptide 20-44 (P20-44), on sperm motility, acrosomal integrity, and mitochondrial functionality. CAP37 expression by neutrophils undergoing ASA- and C-dependent sperm phagocytosis was increased as measured by flow cytometry. Exposure of motile sperm to a cationic P20-44, the bioactive antimicrobial fragment of CAP37, resulted in the loss of sperm motility without disruption of the acrosomal membrane. The sperm immobilizing activity (SIA) of P20-44 was modulated by the length of incubation, the concentration of the peptide, and the pH of the assay medium. SIA induced by P20-44 was partially reversible and was unaffected by the presence of anionic heparin or seminal plasma. Similar to the antimicrobial activity of P20-44, the SIA was also dependent on the presence of a disulfide bond between cysteine residues at positions 26 and 42 and was inhibited by Lipid A. However, the mechanism of action of P20-44 on sperm is not totally dependent on the molecule's cationicity, because five other cationic antimicrobial peptides had no detectable effect on sperm viability. Thus, the mechanism of action of P20-44 on human sperm is different from its cationic antibactericidal effect. These findings established that motile human sperm are sensitive to CAP37 or its synthetic bioactive peptide and suggested that this protein could play a role in neutrophil-mediated immune destruction of sperm in the female genital tract. P20-44 of CAP37 may be useful in investigating the regulation of human sperm motility and to construct "hybrid peptides" with enhanced potency as a component of vaginal contraceptive that could doubly be effective by killing infectious agents and inhibiting sperm transport.

A cationic antimicrobial peptide enhances the infectivity of Coxiella burnetii.

Purified Coxiella burnetii (Nine Mile, phase I) ricketssiae were exposed to a synthetic peptide (CAP37(20-44)) based on the amino acid sequence of CAP37--a 37 K human neutrophil granule-associated cationic antimicrobial protein--and their capacity to infect L929 mouse fibroblast cells was assessed during a 10-day post-exposure period. Because the parasite thrives within the acidic phagolysosome we anticipated that CAP37(20-44) would have no adverse effect on the organism. This was borne out by the experiments; however, to our surprise, treated C. burnetii had a much greater capacity to infect L cells than the non-treated counterpart. We speculate that the peptide exhibits opsonin-like properties, enhancing attachment of the rickettsia to the host cell surface and subsequent entry.

Effects of caffeine and tryptophan on rectal temperature, metabolism, total exercise time, rate of perceived exertion and heart rate.

Stimulant properties during exercise have been attributed to caffeine (CAF) and tryptophan (Trp). The purpose of the present study was to investigate the effects of CAF and Trp ingestion on rectal temperature (Tre), total exercise time (TET), oxygen consumption (VO2), carbon dioxide production (VCO2), pulmonary ventilation (VE), heart rate (HR) and rate of perceived exertion (RPE) during exercise on a cycle ergometer at 80% of maximal work load, in eight healthy male volunteers. Each subject abstained from caffeine for 48 h and from animal-derived foods for 36 h before each experiment. Aerobic capacity was determined on the first day. In consecutive trials, conducted in a double-blind, randomized, crossed-over manner, each subject received capsules containing CAF (10 mg/kg), Trp (1.2 g), a combination of the two (CAF+Trp), and lactose (PLA), 1 h before exercise. Plasma CAF concentration (PC) was measured by high performance liquid chromatography (HPLC), before (basal concentration) and 1 and 2 h after ingestion of the capsules. At both times after CAF or CAF+Trp ingestion, the PC was elevated compared with the basal concentration (P < 0.05). During exercise, significant increases occurred with time in Tre, TET, VO2, VCO2, VE, HR and RPE (P < 0.01) while no significant difference was observed when CAF or CAF+Trp were compared with control values. Under the conditions of this study, CAF and/or Trp did not affect the physiological parameters measured before, during or after exercise at 80% of maximal work load.

CAP37, a neutrophil-derived multifunctional inflammatory mediator.

Cationic antimicrobial protein of M(r) 37 kDa (CAP37) is a multifunctional protein isolated from the granules of human neutrophils, which has important implications in host defense and inflammation. CAP37 was initially recognized for its strong antibiotic activity against Gram-negative bacteria and was viewed as a component of the oxygen-independent killing mechanism of the neutrophil. However, we now know that CAP37 has more far reaching and important functions. It is a physiological protein released during inflammation with a high potential of regulating monocyte/macrophage functions, such as chemotaxis, increased survival, and differentiation. Recently, it has been demonstrated that CAP37 binds endotoxin. It has the structure of a serine esterase but lacks enzymatic activity. The bactericidal and endotoxin binding domains of the molecule have been delineated. The identification of functional peptides should provide new insight into the mechanisms of endotoxin binding, antimicrobial activity, and chemotaxis and in the long term provide key insights into therapies for treating infections and endotoxic shock.

Effects of caffeine and tryptophan on rectal temperature, metabolism, total exercise time, rate of perceived exertion and heart rate

Stimulant properties during exercise have been attributed to cafeine (CAF) and tryptophan (Trp). The purpose of the present study was to investigate the effects of CAF and Trp ingestion on rectal temperature (Tre), total exercise time (TET), oxygen consumption (VO2), carbon dioxide production (VCO2) pulmunary ventilation (VE), heart rate (HR) and rate of perceived exertion (RPE) during exercise on a cycle ergometer at 80 percent of maximal work load, in eight halthy male volunteers. Each subject abstained from caffeine for 48 h and from animal-derived foods for 36 h before each experiment. Aerobic capacity was determined on the first day. In consecutive trials, conducted in a double-blind, randomized, crossed-over manner, each subject recived capsules containing CAF (10mg/Kg), Trp (1.2g), a combination of the two (CAF + TRP), and lactose (PLA), 1 h before exercise. Plasma CAF concentration (PC) was measured by high performance liquid chromatography (HPLC), before (basal concentration) and 1 and 2 h after ingestion of the capsules. At both times after CAF or CAF + Trp ingestion, the PC was elevated compared with the basal concentration (P < 0.05). During exercise, significant increases occured with time in Tre, TET, VO2, VCO2, VE, HR and RPE (P < 0.01) while no significant difference was observed when CAF or CAF+ Trp were compared with control values. Under the conditions of this study, CAF and/or Trp did not affect the physiological parameters measured before, during or after exercise at 80 percent of maximal work load