Geographical variations in arsenic contents in rice plants from Latin America and the Iberian Peninsula in relation to soil conditions

Arsenic is a ubiquitous, toxic element that is efficiently accumulated by rice plants. This study assessed the spatial variability in the total As (tAs) contents and organic and inorganic forms in different types of rice, plant parts (husk, stem, leaves and phytoliths) and residues. Samples were collected in different countries in Latin America (Ecuador, Brazil and Peru) and the Iberian Peninsula (Spain and Portugal). The tAs content in commercial polished rice from the Latin American countries was similar (0.130-0.166 mg kg^-1) and significantly lower than in the rice from the Iberian countries (0.191 ± 0.066 mg kg^-1), and together, the tAs concentration in brown rice (236 ± 0.093 mg kg^-1) was significantly higher than in polished and parboiled rice. The inorganic As (iAs) content in rice was similar in both geographical regions, and the aforementioned difference was attributed to dimethylarsinic acid (DMA). The relative abundance of organic species increased as the tAs content in rice grain increased. A meta-analysis of our and previously reported data confirmed the negative correlation between iAs/tAs and tAs. At low tAs concentrations, inorganic forms are dominant, while at higher values (tAs > 0.300 mg kg^-1) the concentration of organic As increases substantially and DMA becomes the dominant form in rice grain. On the contrary, inorganic arsenic was always the dominant form, mainly as arsenate [As(V)], in leaves and stems. The presence in soils of high concentrations of amorphous Fe and Al oxides and hydroxides, which are capable of strongly adsorbing oxyanions (i.e. arsenate), was associated with low concentrations of As in rice plants. In addition, the presence of high concentrations of As(V) in stems and leaves, low concentration of As in phytoliths, and the As associated with organic matter in stems and husk, together suggest that rice plants take up more As(V) than As(III).

Continuing Education in Health: interprofessional practices in the field of Collective Health

Family Health Support Centres (NASFs, in Portuguese) aim to develop interprofessional practices anchored in the assumptions of Primary Health Care, guided by the criteria of shared care specific professional interventions, management processes, interdisciplinarity, intersectoriality, Continuing Education in Health and health promotion. This health management methodology (Matrix Support) still represents a challenge to workers and managers, as it switches the logic of clinical thought from individual-centred, ambulatory and disciplinary care to collective, territory and interdisciplinary care. This study might illustrate and allow sharing of experiences about a work management format for multidisciplinary teams in Primary Health Care. A partnership between the University and the state health department was established in order to elaborate a collaborative, educational and supportive action. We formed a group of workers in the target area (24 municipalities and 18 teams) who had a focus on Continuing Education in Health using Institutional Analysis as theoretical reference. The main goal of the action was to provide spaces to share experiences and learning in the perspective of Continuing Education in Health. How does Continuing Education in Health support interprofessional practices in the field of Collective Health? Among the main results, we list: reflection about organisation practices of multiprofessional work, reflection about care practices and clinic management in the technical-assistance and pedagogic perspectives of Matrix Support; encouragement to improve the services offered in this level of care and their relationship with other points of the network. This experience showed us the importance of three main aspects: Continuing Education in Health, as a strategy of critical analysis about work and workers; the partnership and integration between teaching and service; and interprofessional formation processes (necessary to NASF and Collective Health).

Key messages

Continuing Education in Health is a strategy to deal with challenges and possibilities of interprofessional practices in the field of Collective Health. Enabling experiences and providing spaces for health professionals to share experience and learning.

164 Gonadotrophin-releasing hormone injection and colour flow Doppler ultrasound of the preovulatory follicle as a tool to increase pregnancy outcome after timed AI in beef cows

The aims of this study were to determine (1) the association between Doppler vascularisation scores (DVS) of the preovulatory follicle (POF) and fertility of beef cows submitted to timed AI (TAI) and (2) whether cows with low DVS benefit from a gonadotrophin-releasing hormone (GnRH) treatment at TAI. Multiparous lactating Nelore cows (Bos indicus; n=69) from a commercial beef farm in the state of Rondônia, Brazil, were enrolled in this study. Cows received 2mg of oestradiol benzoate intramuscularly (Bioestrogen, Biogénesis Bagó) and an intravaginal progesterone-releasing device (1.9g of progesterone; controlled internal drug release, CIDR) to synchronise follicular wave emergence on Day 0. The CIDR device was removed and cows were treated with 150μg of D-cloprostenol intramuscularly (prostaglandin F2α analogue; Croniben), 1mg of oestradiol cypionate intramuscularly, and 300IU of equine chorionic gonadotrophin (Novormon) intramuscularly on Day 8. Cows were then painted with a tail chalk marker to identify those displaying oestrus. All cows were submitted to TAI 48h after CIDR removal. At TAI, occurrence of oestrus was recorded and all cows were examined using transrectal ultrasonography. Blood flow of the POF was evaluated using colour Doppler imaging. Colour Doppler signals present on the follicular wall were subjectively scored using a 1-to-4 scale (1=absence or very low blood flow, and 4=intense blood flow detected on most of the follicular wall surface) adapted from Ginther (2007Ultrasonic Imaging and Animal Reproduction: Color-Doppler Ultrasonography, pages 87-114). Then, cows were divided into three groups according their DVS of the POF: (1) high DVS (DVS ≥3; n=36), (2) low DVS (DVS <3; n=16), and (3) low DVS (DVS <3; n=17) plus a GnRH treatment at TAI. The diameter of the POF was analysed using analysis of variance (PROC GLIMMIX of SAS; SAS Institute Inc.), and the means were compared among groups using Tukey's test. The proportion of cows that displayed oestrus and pregnancy rates was analysed using chi-square test. Cows in the high-DVS group had a larger POF than cows in the low-DVS and low-DVS-GnRH groups (13.2±0.2, 11.7±0.5, and 12.2±0.4, respectively; P<0.05). The proportion of cows that displayed oestrus was greater (P<0.05) in the high-DVS group (72%, 26/36) than in the low-DVS (37.5%, 6/16) or low-DVS-GnRH (53%, 9/17) groups. Finally, greater (P<0.05) pregnancy rates were observed in cows from the high-DVS (47.2%; 17/36) and low-DVS-GnRH (52.9%; 9/17) groups than in cows from the low-DVS group (18.7%; 3/16). The preliminary results from this study demonstrated that diameter of POF is positively associated with DVS. Moreover, cows that presented POF with higher DVS are more likely to become pregnant, and the administration of GnRH to females with low DVS can increase the fertility of beef cows submitted to TAI protocols. This study received funding support from Embrapa (MP1/PC3 project no. 01.03.14.011.00.00) and from CNPq (universal project no. 407307/2016-8).

In vitro and in vivo evaluation of sodium dodecyl sulfate (SDS) as an inactivator of caprine lentivirus (CLV) in colostrum and milk

ABSTRACT The aim of this study was to evaluate in vitro and in vivo the effect of sodium dodecyl sulfate (SDS) on the caprine lentivirus (CLV) in colostrum and milk. This was performed to develop a practical and efficient method of blocking the lactogenic transmission of the virus. In the in vitro experiment, colostrum and milk were treated with 0.25%; 0.50% and 1% SDS. Then, somatic cells of colostrum and milk were submitted to co-culture with caprine synovial membrane cells (CSM). In the in vivo test, goats were fed with colostrum and milk provided from CLV-positive goats treated with SDS in the same concentrations used in the in vitro experiment. Animals were tested by nested polymerase chain reaction (nPCR) and Western blot (WB) assays. In the in vitro experiment, inhibitory activity against CLV without inactivation occurred in colostrum with all SDS concentrations. However, concentrations of 0.25 and 0.5% SDS presented only inhibitory activity against CLV in milk cells, and 1% concentration provided inactivation of the virus. In the in vivo tests, none of the three concentrations of SDS was effective in inactivating LVC in colostrum or goat milk, which was confirmed by seroconversion and presence of proviral DNA in animals afterwards.

Connecting genomic patterns of local adaptation and niche suitability in teosintes

The central abundance hypothesis predicts that local adaptation is a function of the distance to the centre of a species' geographic range. To test this hypothesis, we gathered genomic diversity data from 49 populations, 646 individuals and 33,464 SNPs of two wild relatives of maize, the teosintes Zea mays ssp. parviglumis and Zea. mays. ssp. mexicana. We examined the association between the distance to their climatic and geographic centroids and the enrichment of SNPs bearing signals of adaptation. We identified candidate adaptive SNPs in each population by combining neutrality tests and cline analyses. By applying linear regression models, we found that the number of candidate SNPs is positively associated with niche suitability, while genetic diversity is reduced at the limits of the geographic distribution. Our results suggest that overall, populations located at the limit of the species' niches are adapting locally. We argue that local adaptation to this limit could initiate ecological speciation processes and facilitate adaptation to global change.

Ascaris lumbricoides infection in urban schoolchildren: specific IgE and IL-10 production

BACKGROUND

Helminth infections and allergies are diseases with intense Th2 lymphocytes participation and characterised by a high IgE and Interleukin-(IL) IL-4, IL-5 production and eosinophilia. However, helminths also induce IL-10 production, which may alter the outcome of allergic diseases in infected patients.

OBJECTIVE

This experimental study analyses the relationship between IL-10 production by cell culture from geohelminth infected and non-infected children and specific IgE to Ascaris lumbricoides (Asc) or Blomia tropicalis (BT).

METHODS

IL-10 content in supernatant from peripheral blood mononuclear cell culture from nine helminth infected and eleven non-infected patients was determined by ELISA after in vitro stimulation with Asc or BT extracts.

RESULTS

A positive association was observed between total IgE levels and anti-Ascaris and anti-Blomia tropicalis specific IgE, independent of infection status. For both helminth-infected and non-infected groups, there was no difference in IL-10 production in response to Asc extract, even though anti-Ascaris IgE levels were higher in the latter group. In response to BT stimulus, a lower production of IL-10 by the geohelminth-infected group was observed, but with no relationship between IL-10 production and specific IgE to BT.

CONCLUSION

The results suggest that anti-Ascaris IgE in non-infected patients may be associated to a resistance to parasites. Levels of specific IgE to parasite antigens or B. tropicalis allergen were not impaired by IL-10 production in children from an urban area in which geohelminthiasis is endemic.

Performance of serum-supplemented and serum-free media in IFNgamma Elispot Assays for human T cells

The choice of serum for supplementation of media for T cell assays and in particular, Elispot has been a major challenge for assay performance, standardization, optimization, and reproducibility. The Assay Working Group of the Cancer Vaccine Consortium (CVC-CRI) has recently identified the choice of serum to be the leading cause for variability and suboptimal performance in large international Elispot proficiency panels. Therefore, a serum task force was initiated to compare the performance of commercially available serum-free media to laboratories' own medium/serum combinations. The objective of this project was to investigate whether a serum-free medium exists that performs as well as lab-own serum/media combinations with regard to antigen-specific responses and background reactivity in Elispot. In this way, a straightforward solution could be provided to address the serum challenge. Eleven laboratories tested peripheral blood mononuclear cells (PBMC) from four donors for their reactivity against two peptide pools, following their own Standard Operating Procedure (SOP). Each laboratory performed five simultaneous experiments with the same SOP, the only difference between the experiments was the medium used. The five media were lab-own serum-supplemented medium, AIM-V, CTL, Optmizer, and X-Vivo. The serum task force results demonstrate compellingly that serum-free media perform as well as qualified medium/serum combinations, independent of the applied SOP. Recovery and viability of cells are largely unaffected by serum-free conditions even after overnight resting. Furthermore, one serum-free medium was identified that appears to enhance antigen-specific IFNgamma-secretion.

Effects of biosolids application on nitrogen dynamics and microbial structure in a saline-sodic soil of the former Lake Texcoco (Mexico)

The saline-sodic soil of the former Lake Texcoco, a large area exposed to desertification, is a unique environment, but little is known about its microbial ecology. The objective of this study was to examine bacterial community structure, activity, and function when biosolids were added to microcosms. The application rates were such that 0, 66, 132, or 265 mg total Nk g(-1) were added with the biosolids (total C and N content 158 and 11.5 g kg(-1) dry biosolids, respectively). Approximately 60% of the biosolids were mineralized within 90 days. Microbial respiration and to a lesser extent ammonification and nitrification, increased after biosolids application. The rRNA intergenic spacer analysis (RISA) patterns for the biosolids and unamended soil bacterial communities were different, indicating that the microorganisms in the biosolids were distinct from the native population. It appears that the survival of the allochthonous microorganisms was short, presumably due to the adverse soil conditions.

Proficiency testing for the determination of pesticides in mango pulp: a view of the employed chromatographic techniques and the evaluation of laboratories' performance

The proficiency testing for determination of pesticides residues in mango pulp was the third work of the partnership established by INMETRO and INCQS/Fiocruz. Three mango pulp samples were sent to each participant laboratory, two being spiked with the pesticides and one exempt of pesticides. The added pesticides were: deltamethrin, ethion, fenitrothion, malathion, and permethrin. The evaluation of the results of the homogeneity and the stability tests, as well as the determination of the assigned value was made in agreement with ISO GUIDE 35 and ISO 13528, assuming the samples were considered homogeneous and stable for the studied period. The assigned values and the standard deviation for proficiency evaluation was calculated using the robust algorithm, according to ISO 13528, and the evaluation of the results was carried through in accordance with ABNT ISO/IEC Guide 43-1. The z-score graphs and confidence ellipse was also used in the evaluation of the results. In the evaluation carried through from the values of the z-scores, 71% of the reported results were considered satisfactory based on the results found for this index. The evaluation of the analytical viability for the determination of each pesticide and of the analytical capacity of the participant laboratories was carried through. A summarized view of the chromatographic techniques and of preparation of sample used by the participant laboratories was also carried through in this work.

Nitrogen fixation in microbial mat and stromatolite communities from Cuatro Cienegas, Mexico

Nitrogen fixation (nitrogenase activity, NA) of a microbial mat and a living stromatolite from Cuatro Cienegas, Mexico, was examined over spring, summer, and winter of 2004. The goal of the study was to characterize the diazotrophic community through molecular analysis of the nifH gene and using inhibitors of sulfate reduction and oxygenic and anoxygenic photosynthesis. We also evaluated the role of ultraviolet radiation on the diazotrophic activity of the microbial communities. Both microbial communities showed patterns of NA with maximum rates during the day that decreased significantly with 3-3,4-dichlorophenyl-1',1'-dimethylurea, suggesting the potential importance of heterocystous cyanobacteria. There is also evidence of NA by sulfur-reducing bacteria in both microbial communities suggested by the negative effect exerted by the addition of sodium molybdate. Elimination of infrared and ultraviolet radiation had no effect on NA. Both microbial communities had nifH sequences that related to group I, including cyanobacteria and purple sulfur and nonsulfur bacteria, as well as group II nitrogenases, including sulfur reducing and green sulfur bacteria.

Zinc pretreatment prevents hepatic stellate cells from cadmium-produced oxidative damage

Pretreatment with zinc produces tolerance to several cadmium toxic effects. This study was performed to further elucidate the mechanism of zinc-induced tolerance to cadmium cytotoxicity in a rat hepatic stellate cell line (CFSC-2G). Twenty four hours after seeding, cells were treated with 60 micromol/L ZnCl2 for 24 h. Following zinc pretreatment, cells were exposed to 3 micromol/L and 5 micromol/L CdCl2 for an additional 24 h. The toxicity of cadmium was significantly reduced in the zinc-pretreated cells. Zinc pretreatment produced a decrease in lipid peroxidation damage of cadmium-treated cells. Glutathione cell content diminished 33% and 43% as a result of 3 micromol/L and 5 micromol/ L CdCl2 treatment, respectively. Cell pretreatment with zinc recovered glutathione content at control cells level. Catalase and glutathione peroxidase activities were also recovered to control values with zinc pretreatment. Cadmium (5 micromol/L) was able to induce 39% the expression of alpha1 collagen (I) gene after 1 h treatment, while zinc pretreatment prevented this cadmium profibrogenic effect. We also examined the production of heat shock protein 70 (Hsp70) as a cellular response to oxidative stress produced by cadmium. By Western blot analysis, a 1.3 and 3 times increment in Hsp70, with 3 micromol/L and 5 micromol/L CdCl2 treatment, respectively, was observed. Zinc pretreatment prevented the production of Hsp70. Metallothionein-II (MT-II) gene expression was induced by cadmium, but the induction was unaffected with zinc pretreatment. These data suggest that zinc-induced protection against the cytotoxicity of cadmium in stellate cells may be related to the maintenance of normal redox balance inside the cell.

Weeds as Alternative Hosts of the Citrus, Coffee, and Plum Strains of Xylella fastidiosa in Brazil

In Brazil, Xylella fastidiosa is present in citrus (Citrus sinensis), coffee (Coffea arabica), and plum (Prunus sp.) crops, causing the citrus variegated chlorosis (CVC), coffee leaf scorch (CLS), and plum leaf scald (PLS). Also present in these crops and infesting weeds, which ultimately could serve as sources of inoculum for the cultivated trees, are diverse populations of xylem-feeding leafhopper vectors. In order to assess host range of X. fastidiosa among weeds and to better understand their role in epidemics, field surveys, mechanical inoculations, and insect transmission tests were conducted. Polymerase chain reaction (PCR) and culture plating were used to detect the pathogen from plant tissues. X. fastidiosa was detected in 10 out of 23 species of the weed plants sampled in two citrus groves affected by CVC. None of the weed plants showed external symptoms. In the greenhouse, the average percentages of infection on plants mechanically inoculated with the CVC, CLS, and PLS strains of X. fastidiosa were, respectively, 25, 10, 0 in Medicago sativa; 70, 45, 20 in Echinochloa crus-galli; 45, 30, 0 in Brachiaria decumbens; 72, 70, 40 in Brachiaria plantaginea; 13, 10, 0 in Digitaria horizontalis; 31, 30, 0 in Solanum americanum; and 17, 0, 0 in Bidens pilosa. Symptoms were observed only in S. americanum and citrus and only when inoculated with the CVC strain. In insect transmission tests, the grass leafhopper Ferrariana trivittata was first caged on citrus plants showing CVC symptoms and then on healthy citrus and on the four most common weeds. No plants tested positive by PCR or culture, or showed symptoms for at least 4 months after inoculation. The amount of X. fastidiosa cells that may accumulate in weeds inoculated by leafhoppers is probably under insect acquisition thresholds, a factor that would limit their importance to the CVC epidemics, as studies on spatial distribution of diseased citrus trees over time indicate.

Pentoxifylline diminished acetaldehyde-induced collagen production in hepatic stellate cells by decreasing interleukin-6 expression

The effect of pentoxifylline (PTX), a methylxanthine derivative, on collagen induction and secretion and on the production of mRNA of two fibrogenic cytokines: interleukin-6 and transforming growth factor-beta(1) (IL-6 and TGF-beta(1)) in a rat hepatic stellate cell line (CFSC-2G) exposed to acetaldehyde was studied. CFSC-2G cells were treated with 175 microM acetaldehyde for 24h. The cells were then exposed to a medium containing 200 microM PTX. Collagen secretion, increased 2.6 times in acetaldehyde treated cells. Cells exposed to acetaldehyde and treated with PTX diminished collagen secretion to control values and decreased alpha(1)(I) collagen mRNA by 15%. Reverse transcriptase-polymerase chain reaction (RT-PCR) assays of TGF-beta(1) mRNA showed no variation in different experimental conditions. However, PTX induced a decrease of 32% in IL-6 mRNA in acetaldehyde-treated cells. CFSC-2G cells treated with anti-IL-6 monoclonal antibody, 15min before acetaldehyde was added, did not present an increase in alpha(1)(I) collagen mRNA. These results show that PTX inhibits the expression of alpha(1)(I) collagen via the inhibition of IL-6 in acetaldehyde treated cells. The effect herein reported on IL-6 and alpha(1)(I) collagen mRNA adds to the previously described effect of PTX, which could be useful in the fibrogenic process induced by acetaldehyde.

Does experimental evolution reflect patterns in natural populations? E. coli strains from long-term studies compared with wild isolates

Our results show that experimental evolution mimics evolution in nature. In particular, only 1,000 generations of periodic recombination with immigrant genotypes is enough for linkage disequilibrium values in experimental populations to change from a maximum linkage value to a value similar to the one observed in wild strains of E. coli. Our analysis suggests an analogy between the recombination experiment and the evolutionary history of E. coli; the E. coli genome is a patchwork of genes laterally inserted in a common backbone, and the experimental E. coli chromosome is a patchwork where some sites are highly prone to recombination and others are very clonal. In addition, we propose a population model for wild E. coli where gene flow (recombination and migration) are an important source of genetic variation, and where certain hosts act as selective sieves; i.e., the host digestive system allows only certain strains to adhere and prosper as resident strains generating a particular microbiota in each host. Therefore we suggest that the strains from a wide range of wild hosts from different regions of the world may present an ecotypic structure where adaptation to the host may play an important role in the population structure.

Analysis of the regulatory region of the heat-shock gene rpoH of Escherichia coli strains isolated from non-human hosts

The regulatory region of the gene for sigma32, rpoH, of Escherichia coli strains isolated from non-human hosts and different geographic regions, was sequenced and compared with that of E. coli K12. The main nucleotide changes observed are localized to the right inverted octamer motif of the CytR box. The effect of these changes was evaluated using transcriptional fusions. The results presented could guide further studies on the transcription regulation of rpoH using E. coli K12 as a model.

The elements of the locus of enterocyte effacement in human and wild mammal isolates of Escherichia coli: evolution by assemblage or disruption?

Escherichia coli is an excellent model for studying the evolution of pathogenicity since within one species various genes can be found in pathogenic islands and plasmids causing a wide spectrum of virulence. A collection of 122 strains from different human and wild mammal hosts were analysed by PCR and Southern hybridization for the presence of a subset of the genes included in the LEE (locus of enterocyte effacement). In the PCR analysis, two markers (cesT/eae and espB genes) were found together in more strains (25.4%) than either were found alone. The cesT/eae gene was less frequently found alone (8.2%) than was the espB gene (15.6%). Four regions of the LEE were analysed in a subsample of 25 strains using Southern hybridization. The four regions were all present (44%), all absent (12%) or present in different combinations (44%) in a given strain. The flanking regions of the LEE showed the highest rate of hybridization (in 72% of the strains). The results indicate that the LEE is a dynamic genetic entity, both the complete gene cluster and the individual genes. The genes that comprise this locus seem to be horizontally acquired (or lost) in an independent way and may control other functions in non-pathogenic E. coli lineages. In this way, horizontal transfer may allow the gradual stepwise construction of gene cassettes facilitating coordinate regulation and expression of novel functions.

Metadoxine prevents damage produced by ethanol and acetaldehyde in hepatocyte and hepatic stellate cells in culture

Metadoxine (pyridoxine-pyrrolidone carboxylate) has been reported to improve liver function tests in alcoholic patients. In the present work we have investigated the effect of metadoxine on some parameters of cellular damage in hepatocytes and hepatic stellate cells in culture treated with ethanol and acetaldehyde. HepG2 and CFSC-2G cells were treated with 50 mM ethanol or 175 microM acetaldehyde as initial concentration in the presence or absence of 10 microg ml(-1) of metadoxine. Twenty-four hours later reduced and oxidized glutathione content, lipid peroxidation damage, collagen secretion and IL-6, IL-8 and TNF- alpha secretion were determined. Our results suggest that metadoxine prevents glutathione depletion and the increase in lipid peroxidation damage caused by ethanol and acetaldehyde in HepG2 cells. In hepatic stellate cells, metadoxine prevents the increase in collagen and attenuated TNF- alpha secretion caused by acetaldehyde. Thus, metadoxine could be useful in preventing the damage produced in early stages of alcoholic liver disease as it prevents the redox imbalance of the hepatocytes and prevents TNF- alpha induction, one of the earliest events in hepatic damage.

Effect of endotoxin pretreatment on hepatic stellate cell response to ethanol and acetaldehyde

BACKGROUND AND AIM

The role of endotoxin in alcohol-induced liver damage is well recognized. How pre-exposure to endotoxin might affect alcohol injury is not known. We herein studied the effect of endotoxin pretreatment on hepatic stellate cell (HSC) response to ethanol and acetaldehyde.

METHODS

Rat HSC (CFSC-2G) were exposed to media supplemented with 1 microg/mL lipopolysaccharide (LPS). This was followed by a 24 h exposure to media containing LPS plus 50 mmol/L ethanol or 175 micromol/L acetaldehyde. Lipid peroxidation, collagen, and tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and transforming growth factor (TGF)-beta1 secretion were determined at the end of both periods of exposure.

RESULTS

Lipopolysaccharide pretreatment did not modify lipid peroxidation induced by ethanol or acetaldehyde alone. Glutathione (GSH) content decreased to 4.2 +/- 0.5 and 16.3 +/- 0.8 nmol protein after exposure to ethanol or acetaldehyde alone, and decreased further with LPS pretreatment (2.4 +/- 0.2 and 2.7 +/- 0.3 nmol/mg protein, respectively). Oxidized GSH (GSSG) content increased in ethanol and acetaldehyde LPS-pretreated cells only. Collagen secretion increased to 988 +/- 82 and 1169 +/- 91 microg/10(6) cells after exposure to acetaldehyde or LPS alone. Lipopolysaccharide pretreatment enhanced collagen secretion significantly in both ethanol- and acetaldehyde-treated cells (969 +/- 56 and 1360 +/- 72 microg/10(6) cells, respectively). Interleukin-6 production increased to 288 +/- 48, 1195 +/- 86 and 247 +/- 35 pg/mL per 10(6) cells after ethanol, acetaldehyde and LPS exposure, and increased further with LPS pretreatment in ethanol-exposed cells (680 +/- 23 pg/mL 10(6) cells).

CONCLUSION

Lipopolysaccharide pretreatment of HSC adds to the damage produced by ethanol and acetaldehyde by diminishing GSH content and increasing GSSG content, collagen and IL-6 secretion.

The interaction of protein structure, selection, and recombination on the evolution of the type-1 fimbrial major subunit (fimA) from Escherichia coli

Fimbrial adhesins allow bacteria to interact with and attach to their environment. The bacteria possibly benefit from these interactions, but all external structures including adhesins also allow bacteria to be identified by other organisms. Thus adhesion molecules might be under multiple forms of selection including selection to constrain functional interactions or evolve novel epitopes to avoid recognition. We address these issues by studying genetic diversity in the Escherichia coli type-1 fimbrial major subunit, fimA. Overall, sequence diversity in fimA is high (pi = 0.07) relative to that in other E. coli genes. High diversity is a function of positive diversifying selection, as detected by d(N)/d(S) ratios higher than 1.0, and amino acid residuces subject to diversifying selection are nonrandomly clustered on the exterior surface of the peptide. In addition, McDonald and Kreitman tests suggest that there has been historical but not current directional selection at fimA between E. coli and Salmonella. Finally, some regions of the fimA peptide appear to be under strong structural constraint within E. coli, particularly the interior regions of the molecule that is involved in subunit to subunit interaction. Recombination also plays a major role contributing to E. coli fimA allelic variation and estimates of recombination (2N(e)c) and mutation (2N(e)mu) are about the same. Recombination may act to separate the diverse evolutionary forces in different regions of the fimA peptide.

Cytokine response and oxidative stress produced by ethanol, acetaldehyde and endotoxin treatment in HepG2 cells

BACKGROUND

Inflammatory mediators, including cytokines and reactive oxygen species, are associated with the pathology of chronic liver disease. Hepatocytes are generally considered as targets but not producers of these important mediators.

OBJECTIVES

To investigate whether cells of hepatocellular lineage are a potential source of various cytokines we estimated the expression and secretion of tumor necrosis factor alpha, transforming growth factor beta 1, and interleukins 1 beta, 6 and 8 in the culture of well-differentiated human HepG2 cells treated for 24 hours with ethanol, acetaldehyde and lipopolysaccharide. Lipid peroxidation damage, glutathione content and glutathione peroxidase, catalase and superoxide dismutase activity were also determined.

METHODS

HepG2 cells were treated for 24 hours with ethanol (50 mM), acetaldehyde (175 microM) and LPS (1 microgram/ml). TNF-alpha, TGF-beta, IL-1 beta, IL-6 and IL-8 mRNA were determined by reverse transcriptase polymerase chain reaction and secretion by enzyme-linked immunoassay. Lipid peroxidation damage, glutathione content and antioxidant enzyme activities were determined spectrophotometrically.

RESULTS

Exposure to ethanol for 24 hours induced the expression of TNF-alpha and TGF-beta 1, secretion of IL-1 beta and TGF-beta 1 and decreased catalase activity. Acetaldehyde markedly increased TNF-alpha and IL-8 expression, stimulated IL-1 beta and IL-8 secretion, increased lipid peroxidation damage and decreased catalase activity, while LPS exposure induced the expression of TNF-alpha, TGF-beta 1, IL-6 and IL-8, the secretion of TGF-beta 1, IL-1 beta, IL-6 and IL-8, and a decrease in catalase activity. No change in GSH, GSHPx or SOD was found in any experimental condition.

CONCLUSIONS

The present studies confirm and extend the notion that hepatocytes respond to ethanol, acetaldehyde and LPS-producing cytokines. Oxidative stress produced by the toxic injury plays an important role in this response through up-regulation of inflammatory cytokines.

Genetic structure of natural populations of Escherichia coli in wild hosts on different continents

Current knowledge of genotypic and phenotypic diversity in the species Escherichia coli is based almost entirely on strains recovered from humans or zoo animals. In this study, we analyzed a collection of 202 strains obtained from 81 mammalian species representing 39 families and 14 orders in Australia and the Americas, as well as several reference strains; we also included a strain from a reptile and 10 from different families of birds collected in Mexico. The strains were characterized genotypically by multilocus enzyme electrophoresis (MLEE) and phenotypically by patterns of sugar utilization, antibiotic resistance, and plasmid profile. MLEE analysis yielded an estimated genetic diversity (H) of 0.682 for 11 loci. The observed genetic diversity in this sample is the greatest yet reported for E. coli. However, this genetic diversity is not randomly distributed; geographic effects and host taxonomic group accounted for most of the genetic differentiation. The genetic relationship among the strains showed that they are more associated by origin and host order than is expected by chance. In a dendrogram, the ancestral cluster includes primarily strains from Australia and ECOR strains from groups B and C. The most differentiated E. coli in our analysis are strains from Mexican carnivores and strains from humans, including those in the ECOR group A. The kinds and numbers of sugars utilized by the strains varied by host taxonomic group and country of origin. Strains isolated from bats were found to exploit the greatest range of sugars, while those from primates utilized the fewest. Toxins are more frequent in strains from rodents from both continents than in any other taxonomic group. Strains from Mexican wild mammals were, on average, as resistant to antibiotics as strains from humans in cities. On average, the Australian strains presented a lower antibiotic resistance than the Mexican strains. However, strains recovered from hosts in cities carried significantly more plasmids than did strains isolated from wild mammals. Previous studies have shown that natural populations of E. coli harbor an extensive genetic diversity that is organized in a limited number of clones. However, knowledge of this worldwide bacterium has been limited. Here, we suggest that the strains from a wide range of wild hosts from different regions of the world are organized in an ecotypic structure where adaptation to the host plays an important role in the population structure.

Cytokines, growth factors, and oxidative stress in HepG2 cells treated with ethanol, acetaldehyde, and LPS

Inflammatory mediators, including cytokines, growth factors, and reactive oxygen species, are associated with the pathology of chronic liver disease. In the liver, cytokine and growth factor secretion are usually associated with nonparenchymal cells, particularly Kupffer cells. In the present studies, the effect of 24 and 72 h administration of ethanol (50 mM). acetaldehyde (175 microM), and LPS (1 microg/ml) were studied on the expression and secretion of TNF-alpha, IL-1beta, IL-6, and TGF-beta3, lipid peroxidation damage and glutathion content in HepG2 cell cultures. A 24 h exposure to ethanol induced the expression of TNF-alpha and TGF-beta1, and the secretion of IL-1beta and TGF-beta1. With the same period of treatment, acetaldehyde markedly increased TNF-alpha expression, and stimulated IL-1beta secretion, while LPS exposure induced the expression of TNF-alpha, IL-6, and TGF-beta1, and the secretion of IL-1beta, IL-6, and TGF-beta1. A reduced in TNF-alpha response and TGF-beta1 expression were observed after 72 h exposure to ethanol. A 72 h acetaldehyde exposure decreased markedly TNF-alpha expression and stimulated a previously absent TGF-beta1 response. With the same time of exposure, LPS reduced slightly TGF-beta1 expression, and decreased its secretion. IL-1beta and IL-6 were not detected under 72 h exposure conditions. Lipid peroxidation damage was increased in all treatments, but higher values were found in 72 h treatments. Glutathion content diminished in all treatments. These findings suggest that HepG2 cells, independent of other cells such as Kupffer or macrophages, participate in a differential cytokine, growth factor and oxidative stress response, which differs according to the toxic agent and the time of exposure.

DNA damage produced by cadmium in a human fetal hepatic cell line

Cadmium (Cd) is one of the most important heavy metal environmental toxicants. It alters a wide variety of cellular and biochemical processes. The objective of this work was to study DNA damage and recovery after acute and chronic CdCl2 treatment in a human fetal hepatic cell line (WRL-68 cells). Using the alkaline microgel electrophoresis assay that detects DNA single-strand breaks and/or alkali-labile sites in individual cells, we evaluated for levels of DNA damage. The mean migration length in control cells was 35.37+/-1. 43 microm (8% damaged cells), whereas the mean migration in cells treated with 0.005 microM CdCl2 for 3 h (acute low dose) was 65. 87+/-2.07 microm (88% damaged cells). Treatment with 0.01 microM CdCl2 for the same time (acute high dose) increased the mean migration length to 125.79+/-2.91 microm (92% damaged cells). However, a 0.005 microM CdCl2 treatment for 7 days (chronic treatment) only increased 65% DNA migration to 58.38+/-2.59 microm (88% damaged nucleus). Lipoperoxidative damage expressed as malondialdehyde (MDA) production per milligram of protein was 15. 7+/-2.6 for control cells, whereas in Cd-treated cells the values were 20.2+/-2.4 (acute low dose), 22.9+/-2.2 (acute high dose), and 22.6+/-2.1 (chronic treatment). To study the repair of DNA damage, cells were washed with 0.01 microM meso-2,3-dimercaptosuccinic acid (DMSA), and fresh Dulbecco's modified essential medium (DMEM) added. The percentage of damaged cells diminished after 90 min, with DNA migration returning to control values by 120 min. Cd treatment produced DNA single-strand breaks and the damage was greater in acute high dose treated cells. Lipid peroxidation values did not correlate with DNA single-strand breaks.

Uptake, cellular distribution and DNA damage produced by mercuric chloride in a human fetal hepatic cell line

A human hepatic cell line (WRL-68 cells) was employed to investigate the uptake of the toxic heavy metal mercury. Hg accumulation in WRL-68 cells is a time and concentration dependent process. A rapid initial phase of uptake was followed by a second slower phase. The transport does not require energy and at low HgCl2 concentrations (<50 microM) Hg transport occurs by temperature-insensitive processes. Subcellular distribution of Hg was: 48% in mitochondria, 38% in nucleus and only 8% in cytosolic fraction and 7% in microsomes. Little is known at the molecular level concerning the genotoxic effects following the acute exposure of eucaryotic cells to low concentrations of Hg. Our results showed that Hg induced DNA single-strand breaks or alkali labile sites using the single-cell gel electrophoresis assay (Comet assay). The percentage of damaged nucleus and the average length of DNA migration increased as metal concentration and time exposure increased. Lipid peroxidation, determined as malondialdehyde production in the presence of thiobarbituric acid, followed the same tendency, increased as HgCl2 concentration and time of exposure increased. DNA damage recovery took 8 h after partial metal removed with PBS-EGTA.

Cadmium uptake by a human hepatic cell line (WRL-68 cells)

A hepatic human cell line (WRL-68 cells) was employed to investigate the uptake of the toxic heavy metal cadmium. Cd accumulation in WRL-68 cells is a time-, temperature- and concentration-dependent process. A rapid initial phase of uptake was followed by a second slower phase. The transport does not require energy and 55% of Cd transport occurs by temperature-insensitive processes, possibly by diffusion. The rest of Cd transport (45%) occurs by temperature-sensitive processes, probably ion channels and carriers, that involve interaction with sulfhydryl groups. The calcium channel blockers nifedipine and verapamil inhibit the uptake of cadmium, with an inhibition of 35% after 30 min incubation with 100 microM verapamil and 10 microM Cd. These data suggest that about one third of the Cd enters WRL-68 cells through the calcium channels. The toxic metals appear to use the transport pathways that exist for biologically essential metals. Our results in human hepatic cells are very similar to those reported in cultured rat hepatocytes. It appears that transport pathways available for Cd uptake are similar and independent of the species of hepatocyte origin. Moreover, the WRL-68 cell line seems to be an excellent in vitro model to study the mechanism of cell damage due to Cd.

Comparative study of the damage produced by acute ethanol and acetaldehyde treatment in a human fetal hepatic cell line

The effects of acute ethanol and acetaldehyde treatment on cell proliferation, cell adhesion capacity, neutral red incorporation into lysosomes, glutathione content, protein sulfhydryl compounds, lipid peroxidation, inner mitochondrial membrane integrity (MTT test), lactate dehydrogenase activity (LDH) and ultrastructural alterations were investigated in a human fetal hepatic cell line (WRL-68 cells). WRL-68 cells were used, due to the fact that, although this cell line expresses some hepatic characteristics, it does not express alcohol dehydrogenase or cytochrome P450 activity, so it could be a good model to study the effect of the toxic agents per se. Cells were exposed during 120 min with 200 mM ethanol or 10 mM acetaldehyde. Under these conditions, cells presented 100% viability and no morphological alteration was observed by light microscopy. Acetaldehyde-treated cells reduced their proliferative capacity drastically while the ethanol-treated ones presented no difference with control cells. Cell adhesion to substrate, measured as time required to adhere to the substrate and time required to detach from the substrate, was diminished in acetaldehyde WRL-68-treated cells. Cytotoxicity measures as neutral red and MTT test showed that acetaldehyde-treated cells presented more damage than ethanol-treated ones. Cellular respiratory capacity was compromised by acetaldehyde treatment due to 40% less oxygen consumption than control cells. Lipid peroxidation values, measured as malondialdehyde production, were higher in ethanol-treated WRL-68 cells (127%) than in acetaldehyde-treated ones (60%) to control cell values. Lactate dehydrogenase activity (LDH) in extracellular media of ethanol-treated cells presented the highest values. GSH content was reduced 95% and thiol protein content was diminished severely in acetaldehyde-treated cells. Transmission electron microscopy showed more ultrastructural alterations in cells treated with acetaldehyde. The results indicate that acetaldehyde, like ethanol, produced damage at cellular level, although more damage could be observed in acetaldehyde WRL-68-treated cells.

Effect of cadmium on calcium transport in a human fetal hepatic cell line (WRL-68 cells)

Toxic metals appear to use the transport pathways that exist for biologically essential metals. Calcium uptake in cells occurs through specific membrane channels. Since cadmium inhibits calcium uptake, this study was carried on to elucidate the mechanism of Cd interference with calcium transport using the fetal hepatic cell line WRL-68 as an in vitro model. Ca accumulation by WRL-68 cells presented an initial rapid phase, followed by a sustained phase of slower accumulation over a 60 min period. A concentration of 50 microM CdCl2 produced 39% inhibition of the uptake of CaCl2 (100 microM), while 100 microM nifedipine or verapamil decreased Ca accumulation by 35 and 63%, respectively. All Cd concentrations tested produced significant decrease in Ca uptake in a concentration-dependent manner at 1 min and thereafter, although with 10 microM CdCl2 no significant difference was found after 30 min of incubation. From the Lineweaver-Burk plot, we found that Cd exerted a competitive inhibition on Ca uptake, since there was no significant effect on the Vmax but an increased K(m). A second order rate constant of Cd inactivation of 0.061 mM-1.s-1 was determined from the course of Ca uptake during Cd inhibition. SH groups seemed to play an essential role in Ca inhibition uptake by Cd because the inhibition of Ca accumulation by 50 microM Cd was practically reversed after the addition of dithiothreitol.

[The role of low-molecular-weight heparin in unstable angina, acute myocardial infarction and post-elective percutaneous transluminal coronary angioplasty]

PURPOSE

To evaluate the clinical efficacy and safety of subcutaneous (SC) low molecular weight heparin (LMWH) compared to intravenous (IV) non fractioned heparin (NFH) in unstable angina, acute myocardial infarction and post-percutaneous transluminal coronary angioplasty.

METHODS

From September/92 to April/94, 314 patients were randomized in two groups. Group I-- 154 patients treated with SC LMWH, using in the 1st phase SC LMWH with a dosage of 160 UaXa IC/kg/day (group IA--92 patients), and in the 2nd, a dosage of 320 UaXa IC/kg/day (group IB--62 patients). Group II--160 patients treated with IV NFH 100UI/kg (bolus), followed by 1000UI/h with adjusted dosage by activated partial thromboplastin time.

RESULTS

There was not a statistically significant difference among the three groups in relation to cardiac events, hemorrhagic complications and deaths.

CONCLUSION

The clinical efficacy and safety of SC LMWH in patients with unstable angina, acute myocardial infarction and post-percutaneous transluminal coronary angioplasty were similar to IV NFH with the dosages used in this study.

Cadmium and mercury toxicity in a human fetal hepatic cell line (WRL-68 cells)

The toxic effects of cadmium (Cd) and mercury (Hg), as chloride salts, were studied using an hepatic human fetal cell line (WRL-68 cells). From viability curves and the proliferative capacity of the cell in the presence of the metal, three different cell treatments were chosen, (1) 0.5 microM of the metal chloride for 24 h (acute low dose treatment), (2) 0.5 microM of the metal chloride for 7 days (chronic treatment), and (3) 5 microM of the metal chloride for 24 h (acute high dose treatment). WRL-68 cells grown in the presence of Cd exhibited the same proliferative curve as control cells, whereas in the case of Hg, the cells increased their proliferative capacity. Both metals produced ultrastructural alterations in different degrees, mainly observed as mitochondrial and RER structural changes, depending of the treatment and concentration of the metal used. Cytotoxicity was assessed by measuring the release of lactate dehydrogenase from the cells. Acutely high dose-treated cells showed the highest value for this parameter, and Cd-treated cells presented higher lactate dehydrogenase release than the Hg-treated ones. Cell damage was also measured by alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) activities. Acute high dose Cd treatment caused the highest value of enzymatic release. Lipid peroxidation was significantly different with respect to control cells in chronic and acute high dose treatments with both metals. Metallothionein (MT) induction in response to Hg treatment was not detected. However, a dramatic induction of this protein occurred in Cd-treated cells. WRL-68 cells differentially respond to Cd and Hg making this hepatic fetal human cell line a useful tool in investigating the mechanism of toxicity of these heavy metals.

The effect of chronic and acute ethanol treatment on morphology, lipid peroxidation, enzyme activities and Na+ transport systems on WRL-68 cells

In this study we measured some parameters that are associated with ethanol damage to the liver. The method allowed us to determine the injury that chronic and acute ethanol treatments produce at the cellular level without interference from homeostatic or compensatory mechanisms. The system used is a hepatic fetal human cell line, WRL-68, which retains, in culture, many of the liver-specific functions. WRL-68 cells do not metabolise ethanol, and consequently we could evaluate the effect of ethanol alone. We explored two different conditions: 30 days with 0.1 M ethanol (chronic treatment) and 24 h in the presence of 0.5 M ethanol (acute treatment). 1. The transmission electron microscopy studies revealed, in both treatments, the presence of granules not usually present in the cytoplasm of control cells and morphological mitochondrial alterations in chronically treated cells. 2. Lipid peroxidation, measured as the rate of malondialdehyde production, increased three and a half times in acutely treated cells and about twofold in chronically treated cells. 3. The percentage of total activity (activity in the medium/(activity in the medium + activity of the cells). 100) and the enzymatic activity in the culture medium of gamma glutamyl transpeptidase (GGT), alanine amino transferase (ALAT), aspartate amino transferase (ASAT) and alkaline phosphatase (AI-P), increased. 4. We measured some parameters related to the transport of sodium across the membrane. Cells chronically treated with ethanol had higher rate constants and effluxes than control cells. There was no difference between the total and passive efflux. Ethanol treated cells apparently lacked the ouabain sensitive pathway. In acutely treated cells, the total sodium efflux and the rate constant were enhanced. Sodium pools in the acutely treated cells were diminished and active sodium pumping was seven times higher than in control cells. 5. We determined the number of high affinity ouabain binding sites per cell. Ethanol did not alter the number of pumps, rather it seems to induce a functional alteration. Our results indicate that ethanol per se induces lipid peroxidation, alters enzymatic activities, sodium transport systems, sodium pools and cellular morphology, and that all these changes may be partly responsible for ethanol-induced hepatotoxicity. The data compare favourably with those reported in the literature for many different systems. Therefore our model for studying the mechanism of alcohol effects appears to be valid, with the advantage of being able to compare experiments that can be done in the same system and under the same conditions.

Chronic and acute ethanol treatment modifies fluidity and composition in plasma membranes of a human hepatic cell line (WRL-68)

The aim of this study was to compare the effects of chronic (0.1 mol/L ethanol exposure during 30 days) and acute (0.5 mol/L ethanol exposure during 24 h) ethanol treatment on the physical properties and the lipid composition of plasma membranes of the WRL-68 cells (fetal human hepatic cell line). Using fluorescence polarization we found that ethanol treatment reduced membrane anisotropy due to disorganization of acyl chains in plasma membranes and consequently increased fluidity, as measured with the diphenylhexatriene probe. Addition of ethanol in vitro reduced anisotropy in control plasma membranes, whereas chronically ethanol-treated plasma membranes were relatively tolerant to the in vitro addition of ethanol. Acutely ethanol-treated plasma membranes exhibited a smaller anisotropy parameter value than control plasma membranes. We found a decrease in total phospholipid content in acute ethanol WRL-68 plasma membranes. Cholesterol content was increased in both ethanol treatments, and we also found a significant decrease in phosphatidylinositol and phosphatidylcholine and an increase in phosphatidylethanolamine content in ethanol-treated plasma membranes. Our data showed that ethanol treatment decreased the anisotropy parameter consistently with increased fluidity, while increasing the cholesterol/phospholipid ratio of plasma membranes of WRL-68 cells, but only chronically ethanol-treated plasma membranes exhibited tolerance to the in vitro addition of ethanol. It is important to note that some changes that were interpreted as a result of chronic ethanol treatment were also present in short-period ethanol treatments.

Correlation of regional cerebral blood flow equivalents measured by single photon emission computerized tomography with P300 latency and eye movement abnormality in schizophrenia

Single photon emission tomography with the intravenous blood flow marker 99mTc-exametazime was carried out in 14 acutely ill drug-free schizophrenic patients from whom P300 event-related potential, smooth eye pursuit eye tracking and verbal fluency were measured within a few days of scanning. Smooth pursuit eye movement abnormality correlated significantly with abnormal tracer uptake in superior pre-frontal cortex on the right and left and inferior pre-frontal cortex on the left. Abnormal eye movement was also associated with higher tracer uptake in left anterior cingulate and left posterior cingulate. P300 latency was significantly correlated with higher tracer uptake in left superior pre-frontal and left parietal regions. Verbal fluency performance was negatively correlated with tracer uptake in left frontal region. Eye tracking abnormality in schizophrenia is associated with bilateral frontal lobe disturbance and P300 latency increase with left-sided frontal and temporoparietal dysfunction. There was, however, a significant inverse relation between eye tracking abnormalities and abnormal perfusion in the left anterior cingulate region.

Expression of some hepatocyte-like functional properties of WRL-68 cells in culture

Some morphologic and functional characteristics of an hepatic fetal human epithelial cell line (WRL-68 cells) were determined to validate the use of these cells as an in vitro hepatic model. WRL-68 cells have a morphologic structure similar to hepatocytes and hepatic primary cultures. They secrete alpha-feto protein and albumin and exhibit a cytokeratin pattern similar to other hepatic cultures. WRL-68 cells preserve the activity of some characteristic or specific liver enzymes or both used in clinical chemistry for the diagnosis of hepatic disorders, i.e. alanine amino transferase, aspartate amino transferase, gamma-glutamyl transpeptidase, and alkaline phosphatase.

Epistatic effects of promoter and repressor functions of the Tn10 tetracycline-resistance operon of the fitness of Escherichia coli

We have been studying the effects of expression of plasmid-borne, Tn10-encoded, tetracycline resistance on the fitness of Escherichia coli K12. We previously demonstrated large reductions in fitness resulting from induced or constitutive expression of the resistance protein; however, any residual expression by the repressed operon was so slight that possession of an inducible resistance function imposed essentially no burden in the absence of antibiotic. Here, we demonstrate two distinct disadvantages for inducible genotypes relative to isogenic constitutive constructs. During the transition from antibiotic-free to antibiotic-containing media, the inducible genotype experiences a longer lag phase prior to growth. In the sustained presence of antibiotic, full induction of the resistance function in the inducible genotype is prevented by the continued action of its repressor. However, these disadvantages may be reduced by increasing the strength of the promoter for the resistance gene in the inducible genotype. Simultaneous consideration of the mode of gene regulation (i.e. constitutive or inducible) and the strength of the resistance-gene promoter (i.e. maximum level of expression) indicates an adaptive landscape with very strong epistasis and, perhaps, multiple fitness peaks.