Exposure to cadmium during in vitro maturation at environmental nanomolar levels impairs oocyte fertilization through oxidative damage: A large animal model study

Cadmium is a highly toxic heavy metal with negative effects on oocyte fertilization. The aim of this study was to analyse whether cadmium-induced impairment of fertilization is caused by mitochondria dysfunction and oxidative stress in the cumulus-oocyte complex (COC). Preliminarily, 19 trace element levels were measured in ovaries from juvenile and adult ewes and age-related cadmium ovarian bioaccumulation at nanomolar concentrations was found. COCs from juvenile and adult ewes, exposed during in vitro maturation to 1nM or 100nM CdCl₂, and subjected to in vitro fertilization showed significantly lower fertilization rates in exposed COCs compared with controls. In vitro matured exposed and control COCs underwent confocal microscopy analysis of mitochondria activity and reactive oxygen species (ROS) levels and lipid peroxidation (LPO) assay at cumulus cell and oocyte level. In both age groups, cadmium at nanomolar concentrations induced cumulus-oocyte mitochondria over-activity and oxidative damage which were related to impaired oocyte fertilization.

308 VERBASCOSIDE TREATMENT DURING IN VITRO MATURATION IMPROVES THE EMBRYO DEVELOPMENT OF PREPUBERTAL OVINE OOCYTES

Verbascoside (VB), a bioactive polyphenol from olive mill wastewater with known antioxidant activity, was shown to act as a pro-oxidant molecule, by impairing energy/redox status and embryo developmental competence of prepubertal ovine oocytes when added at micromolar concentrations in a continuative 24-h in vitro maturation (IVM) exposure protocol (1). The aim of the present study was to determine whether a lower (nanomolar) VB concentration and a shorter exposure time (2 v. 24 h) during IVM may improve the maturation rates of prepubertal ovine oocytes and their subsequent embryonic development in vitro. Cumulus-oocyte complexes derived from the ovaries of slaughtered 1-mo-old prepubertal sheep oocytes underwent IVM in TCM 199 with 10% oestrus sheep serum, 0.1 IU mL–1 of FSH/LH, and 100 µM cysteamine, in 5% CO2 in air at 38.5°C for 24 h. Based on our previous results (Dell'Aquila et al. 2014 Biomed. Res. Int. 2014, 878062), VB was added in the IVM medium at 1.03 nM, and 2 incubation times (24 and 2 h) were tested. In the 2-h exposure group, after 2 h of exposure to VB, oocytes were washed and cultured up to 24 h without VB. A group of oocytes were cultured in absence of VB, as controls. Matured oocytes were fertilized with frozen-thawed ram semen in SOF medium for 22 h and zygotes were cultured in vitro for 8 days. Metaphase II (MII) cleavage and blastocyst rates were analysed by Chi-squared test. Embryo quality was evaluated by staining and total cell count of the blastocyst and analysis of variance (ANOVA) was applied. Differences were considered to be significant when P < 0.05. Compared to controls, VB treatment at the concentration of 1.03 nM and 24 h of exposure had no effect on MII rates (196/268, 73% v. 226/323, 70% MII/cultured oocytes; P > 0.05). However, this treatment allowed to obtain significantly higher rates of cleaved embryos/MII oocytes (156/196, 80% v. 165/226, 73%; respectively; P < 0.05), blastocyst yield/cleaved embryos (59/156, 38% v. 45/165, 27%, respectively; P < 0.05), and total blastocyst cell numbers (108.62 ± 19.87 v. 89.61 ± 26.32, respectively; P < 0.05) compared to control oocytes. The VB treatment at the same concentration but for 2 h induced only significantly higher cleavage rate (196/210, 93% v. 165/226, 73%; P < 0.05). In conclusion, our results showed that VB treatment at 1.03 nM during 24 h of IVM exerted a positive effect on in vitro embryo development of prepubertal ovine oocytes by increasing the blastocyst yield and their quality. The hypothesis that VB at nanomolar concentrations may improve cumulus-oocyte energy/redox status is under investigation.The authors acknowledge support by the Regione Autonoma della Sardegna (LR 7, Agosto 2007, no. 7, CRP-17602). The authors thank Dr D. Bebbere and L. Falchi, Dept. Veterinary Medicine, Sassari, for statistical analysis.

Influence on functional parameters of intestinal tract induced by short-term exposure to fumonisins contaminated corn chyme samples

The gut is a possible target toward mycotoxin fumonisins (FBs) exposure. The study aims to investigate the effects induced by FBs contaminated-corn chyme samples on functional parameters of human and rat intestine by using Ussing chamber. Fumonisins-contaminated corn and processed corn samples were undergone to in vitro digestion process and then added to luminal side. A reduction (about 90%) of short circuit current (Isc μA/cm(2)) during exposure of human colon tissues to fumonisins-free corn chyme samples was observed, probably related to increased chyme osmolality. This hyperosmotic stress could drain water towards the luminal compartment, modifying Na(+) and Cl(-) transports. The presence of FBs in corn chyme samples, independently to their concentration, did not affect significantly the Isc, probably related to their interference towards epithelial Na(+) transport, as assessed by using a specific inhibitor (Amiloride). The rat colon tract represents a more accessible model to study FBs toxicity showing a similar functional response to human. In the rat small intestine a significant reduction (about 15%) of Isc parameter during exposure to uncontaminated or FBs contaminated corn chyme samples was observed; therefore such model was not suitable to assess the FBs toxicity, probably because the prevalent glucose and amino acids electrogenic absorption overwhelmed the FBs influence on ionic transport.

NADP-glutamate dehydrogenase activity in nonstarter lactic acid bacteria: effects of temperature, pH and NaCl on enzyme activity and expression

AIMS

To screen the glutamate dehydrogenase (GDH) activity of nonstarter lactic acid bacteria (NSLAB) and to determine the effects of temperature, pH and NaCl values used for cheese ripening on enzyme activity and expression of GDH gene.

METHODS AND RESULTS

A subcellular fractionation protocol and specific enzyme assays were used. The effect of temperature, pH and NaCl on enzyme activity was evaluated. The expression of GDH gene was monitored by real-time PCR. One selected strain was also used as adjunct starter for cheese making to evaluate the catabolism of free amino acids and the production of volatile organic compounds (VOC) during cheese ripening. The cytoplasm fraction of all strains showed in vitro NADP-dependent GDH activity. NADP-GDH activity was markedly strain dependent and varied according to the interactions between temperature, pH and NaCl. Lactobacillus plantarum DPPMA49 showed the highest NADP-GDH activity under temperature, pH and NaCl values found during cheese ripening. RT-PCR analysis revealed that GDH expression of Lact. plantarum DPPMA49 was down-expressed by low temperature (<13°C) and over-expressed by NaCl (1·87-5·62%). According to NADP-GDH activity, the highest level of VOC (alcohols, aldehydes, miscellaneous and carboxylic acids) was found in cheeses made with DPPMA49.

CONCLUSIONS

The results of this study may be considered as an example of the influence of temperature, pH and NaCl on enzyme activity and expression of functional genes, such as GDH, in cheese-related bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

It focuses on the phenotypic and molecular characterization of the NADP-GDH in lactobacilli under cheese-ripening conditions. The findings of this study contribute to the knowledge about enzymes involved in the catabolism of amino acids, to be used as an important selection trait for cheese strains.

Influence of in vitro exposure to mycotoxin zearalenone and its derivatives on swine sperm quality

Zearalenone (ZEA) is a fusariotoxin naturally occurring in crops with known estrogenic activity in swine, the most sensitive known species. The metabolism by swine of ZEA, principally into alpha-zearalenol (alpha-ZOL), is considered as a bio-activation because of its high affinity with estrogenic receptors. Discordant data on male reproductive failures induced by ZEA in vivo are described. In this study, we evaluated the effects to boar spermatozoa when they are exposed in vitro to ZEA and its derivatives (alpha-ZOL, beta-ZOL). We analyzed viability, apoptosis (terminal deoxynucleotidyltransferase dUTP nick end-labelling (TUNEL)), sperm chromatin stability (sperm chromatin structure assay (SCSA)) and motility (using computer-aided sperm analysis (CASA)). Each mycotoxin influenced a specific function of spermatic cells. alpha-Zearalenol and ZEA, at picomolar levels, negatively influenced chromatin structure stability and viability, respectively, whereas beta-ZOL negatively influenced the sperm motility at micromolar levels. This study is the first using these direct measures of sperm integrity to show the potential for an adverse effect of ZEA exposure on boar fertility.

Molecular identification and typing of natural whey starter cultures and microbiological and compositional properties of related traditional Mozzarella cheeses

Cell numbers of presumptive lactic acid bacteria varied markedly between 7 natural whey starter cultures (NWSC) used for producing traditional cows' milk Mozzarella cheeses in the Apulia region of Southern Italy. Taxonomic identification revealed a large diversity at species level, including mesophilic and thermophilic lactobacilli, lactococci, streptococci and enterococci. Randomly Amplified Polymorphic DNA (RAPD-PCR), analysis showed the biodiversity among the strains and, for lactobacilli, some relationships with provenience of the natural starter. Cell numbers of presumptive lactic acid bacteria in the corresponding Mozzarella cheeses were similar or higher than those found in the corresponding NWSC. RAPD-PCR analyses showed that most of the strains in cheese originated from the starter. The gross composition varied markedly between the 7 Mozzarella cheeses and ranged from 53-64% moisture, 17-23% protein, 13-20% fat and 0.50-1.61% salt. The values of pH for several samples were above 6.0. As shown by urea-PAGE of the pH 4.6-insoluble nitrogen fractions, cheese samples were characterized by differences in alpha(S1)- and beta-casein hydrolysis. Cheeses also differed with respect to secondary proteolysis as shown by Principal Component Analysis (PCA) of data from RP-HPLC of the pH 4.6-soluble, pH 4.6-70% ethanol-soluble and 70% ethanol-insoluble nitrogen fractions. These differences were attributed to the different microbial composition of the NWSC. Strain selection and optimization of a protocol for producing a natural whey starter culture to be used by dairy factories of the Apulia region appears to be a pre-requisite to standardize the major traits distinguishing this cheese variety.

Influence of mycotoxins on spontaneous contraction in myometrial strips of prepubertal lamb

The effects of mycotoxin zearalenone and their major metabolites alpha- and beta-zearalenol on spontaneous contractions in isolated lamb uterine smooth muscle were examined. The study was carried out on 20 female prepubertal lambs aged between 45 and 50 days. Myometrial strips were set up in two isolated organ baths (10ml) at 37 degrees C and were exposed to increasing concentrations (10(-11)M-10(-6)M) of these mycoestrogens and results were compared with the effect, at the same concentrations, of natural estrogen 17beta-estradiol. Our findings suggest that mycotoxins and 17beta-estradiol, at nanomolar concentrations, rapidly enhance phasic spontaneous smooth muscle contraction. In particular, zearalenone increases the uterine activity similarly to 17beta-estradiol. On the contrary, its metabolite alpha-zearalenol significantly inhibits myometrial contractility.

Cell-cell communication in food related bacteria

Although the study of quorum sensing is relatively recent, it has been well established that bacteria produce, release, detect and respond to small signalling hormone-like molecules called "autoinducers". When a critical threshold concentration of the signal molecule is achieved, bacteria detect its presence and initiate a signalling cascade resulting in changes of target gene expression. Cell-cell communication has been shown within and between species with mechanisms substantially different in Gram-positive and Gram-negative bacteria. The identified quorum-sensing mechanisms in several food related Gram-negative and Gram-positive bacteria, including bacteriocin synthesis, luxS quorum sensing and interactions between sourdough starter lactic acid bacteria are reviewed. The understanding of extracellular signalling may provide a new basis for controlling over molecular and cellular process the deleterious and useful food related bacteria whose behaviour is mostly a consequence of very complex community interactions.

The influence of lycopene on the proliferation of human breast cell line (MCF-7)

Lycopene, a non-provitaminic carotenoid, present in many fruit and vegetables, such as tomatoes and their processed products, has been associated with decreased risk of chronic diseases including cancer. The influence of lycopene on the proliferation of the breast tumour cell line (MCF-7) was tested using MTT and BrdU assays at different time intervals (from 24 to 72h) and dose-response (from 0.125 to 100microM). The induction of Gap Junction Intercellular Communication (GJIC) was evaluated by dye-transfer assay using Lucifer Yellow on monolayer cells treated with different lycopene concentrations (from 0.125 to 5microM) for 6 to 48h. The Minimal Inhibitory Concentration (MIC) of lycopene was of 5microM, after a 24h exposure. A prolonged exposure time (72h) induced a similar inhibitory effect. Lycopene stimulated the functionality of GJIC at concentrations of 1microM after 24h and this effect was dose-dependent. The induction of GJIC by lycopene was confirmed by an increased expression of connexin 43. Collectively, the above data confirm the inhibitor effects of lycopene on MCF-7 cell growth and suggest that lycopene is involved in the modulation of the gap junction intercellular communication in this cell line, as observed for other cancer cell lines.

Investigation of fungal contamination in sheep and goat cheeses in southern Italy

One hundred and twenty-two samples of cheeses made from goat and sheep milk and a mixture of the two types, produced in Southern Italy by industrial establishments or artisans, were analysed for the detection of fungal contamination and the presence of potentially toxigenic moulds. Only organoleptically acceptable cheeses without evident fungal contamination were studied. Among these, 40 were unripened, 30 medium and 52 long ripened cheeses. Moulds were found in 54 of the 122 analysed samples (44.3%). The most contaminated cheeses were the medium and long ripened ones (46.3% and 35.2%), and the industrial cheeses (59.1%). The artisan cheeses were the least contaminated (26.8%). Among the cheeses that tested positive, Penicillium species were the most frequently isolated (72.9%), followed by Geotrichum spp. (7.3%), Aspergillus spp. (4.2%) and Mucor spp. (4.2%). The potentially toxigenic species within the genera Penicillium, Aspergillus and Fusarium were mainly detected in sheep cheeses.

Toxicity and apoptosis induced by the mycotoxins nivalenol, deoxynivalenol and fumonisin B1 in a human erythroleukemia cell line

The toxicity of the mycotoxins nivalenol (NIV), deoxynivalenol (DON) and fumonisin B1 (FB1) were studied in the K562 human erythroleukemia cell line using the Trypan Blue, MTT and BrdU uptake analyses of cytotoxicity, cell metabolism and cell proliferation, respectively. Nuclear staining with propidium iodide and DNA analysis by flow cytometry were used to identify apoptosis and cell cycle distribution. By the MTT and BrdU tests, both NIV and DON were significantly more toxic than FB1 by at least one order of magnitude, with ID50s ranging from 0.5 microM for NIV to 70 microM for FB1. The MTT test indicated that NIV was significantly (approximately four times) more toxic than DON. In contrast, the Trypan Blue test did not reveal any effects of mycotoxin exposure suggesting that, at the concentrations tested, NIV, DON and FB1 did not induce cytotoxicity through plasma membrane damage. Cell cycle analysis suggested apoptotic cytotoxicity, revealing 100% cellular debris at the highest concentrations of NIV and DON and approximately 2.9 times more debris than control at the highest FB1 concentration. Morphological evidence of apoptosis was related to the toxicity of the substances, such that the more toxic NIV and DON resulted in more late stage apoptotic events than FB1. This study suggests that human blood cells are sensitive to mycotoxin exposure, that NIV is more toxic than DON which is more toxic than FB1, and that DNA damage and apoptosis rather than plasma membrane damage and necrosis may be responsible for the observed cytotoxicity.

Angiotensin I-converting-enzyme-inhibitory and antibacterial peptides from Lactobacillus helveticus PR4 proteinase-hydrolyzed caseins of milk from six species

Sodium caseinates prepared from bovine, sheep, goat, pig, buffalo or human milk were hydrolyzed by a partially purified proteinase of Lactobacillus helveticus PR4. Peptides in each hydrolysate were fractionated by reversed-phase fast-protein liquid chromatography. The fractions which showed the highest angiotensin I-converting-enzyme (ACE)-inhibitory or antibacterial activity were sequenced by mass spectrum and Edman degradation analyses. Various ACE-inhibitory peptides were found in the hydrolysates: the bovine alpha(S1)-casein (alpha(S1)-CN) 24-47 fragment (f24-47), f169-193, and beta-CN f58-76; ovine alpha(S1)-CN f1-6 and alpha(S2)-CN f182-185 and f186-188; caprine beta-CN f58-65 and alpha(S2)-CN f182-187; buffalo beta-CN f58-66; and a mixture of three tripeptides originating from human beta-CN. A mixture of peptides with a C-terminal sequence, Pro-Gly-Pro, was found in the most active fraction of the pig sodium caseinate hydrolysate. The highest ACE-inhibitory activity of some peptides corresponded to the concentration of the ACE inhibitor (S)-N-(1-[ethoxycarbonyl]-3-phenylpropyl)-ala-pro maleate (enalapril) of 49.253 micro g/ml (100 micro mol/liter). Several of the above sequences had features in common with other ACE-inhibitory peptides reported in the literature. The 50% inhibitory concentration (IC(50)) of some of the crude peptide fractions was very low (16 to 100 micro g/ml). Some identified peptides were chemically synthesized, and the ACE-inhibitory activity and IC(50)s were confirmed. An antibacterial peptide corresponding to beta-CN f184-210 was identified in human sodium caseinate hydrolysate. It showed a very large spectrum of inhibition against gram-positive and -negative bacteria, including species of potential clinical interest, such as Enterococcus faecium, Bacillus megaterium, Escherichia coli, Listeria innocua, Salmonella spp., Yersinia enterocolitica, and Staphylococcus aureus. The MIC for E. coli F19 was ca. 50 micro g/ml. Once generated, the bioactive peptides were resistant to further degradation by proteinase of L. helveticus PR4 or by trypsin and chymotrypsin.

Survey on mycoflora of cow and buffalo dairy products from Southern Italy

Economic losses of dairy products due to spoilage by yeasts have been increasing in European companies because of the reduced use of preservatives, packaging in modified atmospheres, or new formulations that do not strictly control the growth of these organisms. This study reports the results of a survey of yeast species and populations in 145 samples of cow and buffalo dairy products collected in some regions of Southern Italy. Yeasts were isolated from 74% and 57% of cow and buffalo products, respectively. Candida inconspicua was the predominant species in unripened products from cow's milk, while C. famata was detected in medium and long-term ripened dairy products, mostly in association with other yeasts and with moulds belonging to the genus Penicillium. For dairy products produced from buffalo milk, C. inconspicua was the most important yeast frequently isolated from dairy products. Total yeast populations ranged from 5 x 10(2) to 5 x 10(5) cfu/g, indicating a good hygienic quality of the products. The isolation of C. albicans from one stracciatella sample is noteworthy, as this yeast represents a potential contamination by human. Even though yeasts are considered as environmental contaminants, the occurrence of some of them in dairy products at high levels could represent a risk for human health, in particular for immunocompromised patients.

Toxic effects of the mycotoxin zearalenone and its derivatives on in vitro maturation of bovine oocytes and 17 beta-estradiol levels in mural granulosa cell cultures

Moulds parasites of livestock foodstuffs alter the quality of grains by synthesizing mycotoxins. Zearalenone (ZEA) and its derivatives (alpha- and beta-zearalenol, zeranol, taleranol and zearalanone) are produced by fungi of the genus Fusarium and, after ingestion via contaminated cereals, may lead to fertility disturbances and other reproductive pathologies. Zearalenone, alpha-zearalenol and zearalanone were tested, at levels ranging from 0.3 to 30 microg/ml, in order to evaluate the effect on the in vitro maturation (IVM) rate of bovine oocytes and on the formation of 17 beta-estradiol in supernatants of mural granulosa cells (GC) cultures. These compounds induced dose-dependent oocyte maturation delay and chromatin abnormalities. Maturation of oocytes to metaphase II (M II) was inhibited in oocytes cultured in the presence of 30 microg/ml ZEA, alpha-zearalenol or zearalanone, with a significant increase in chromatin abnormalities occurring in the presence of ZEA (P<0.05) and alpha-zearalenol (P< 0.001). In preliminary trials on 17 beta-estradiol formation, at the same testing concentration, higher levels of 17 beta-estradiol were found in the presence of alpha-zearalenol (mean value 1.6 ng/ml) with respect to ZEA and zearalanone (mean estradiol concentrations of 0.06 and 0.5 ng/ml, respectively). These data demonstrate a negative effect of ZEA and its derivatives on meiotic progression of bovine oocytes, possibly attributable to a toxic mechanism not related to the binding affinity of these compounds to estrogen receptor sites, and support previous observations that alpha-zearalenol acts as a stronger estrogenic inducer than the original molecule (ZEA).

[Familial Mediterranean fever: report of a case]

Familial Mediterranean fever is an autosomal recessive hereditary disease characterised by recurrent fever, poliserositis, chest and/or abdominal pain. Up to date diagnosis is based on clinical symptoms, familial anamnesis and response to colchicine. It is an inflammatory reaction affecting serosal tissues but until recently different hypotheses have been suggested to explain the greatly increased chemotactic activity of the polymorfonuclear leucocytes. Identification of the function of the MEFV gene on chromosome 16 and its protein allows us to understand the pathogenesis of familial Mediterranean fever as well as provides a new diagnostic test and therapeutic measures. We describe a case of an young patient and review the literature.

Arabinose fermentation by Lactobacillus plantarum in sourdough with added pentosans and alphaalpha-L-arabinofuranosidase: a tool to increase the production of acetic acid

Sixty-five strains of obligately and facultatively heterofermentative sourdough lactic acid bacteria were screened for their capacity to grow optimally in the presence of arabinose, ribose and xylose as carbon sources. Lactobacillus alimentarius 15F, Lact. brevis 10A, Lact. fermentum 1F and Lact. plantarum 20B showed higher growth rate, cell yield, acidification rate and production of acetic acid when some pentoses instead of maltose were added to the SDB medium. Lactobacillus plantarum 20B used arabinose also in a synthetic medium where complex growth factors such as yeast extract were omitted. Other Lact. plantarum strains did not show the same property. Pentosan extract was treated with alpha-L-arabinofuranosidase from Aspergillus niger or endo-xylanase from Bacillus subtilis to produce hydrolysates containing mainly arabinose and xylose, respectively. In particular, the hydrolysate containing arabinose substantiated the growth and the production of lactic acid and, especially, of acetic acid by Lact. plantarum 20B. Sourdough fermentation by Lact. plantarum 20B with addition of pentosan extract and alpha-L-arabinofuranosidase increased the acidification rate, titratable acidity and acetic acid content compared with traditional sourdough. A facultatively heterofermentative strain, Lact. plantarum 20B, also produced a sourdough with an optimal fermentation quotient.

[Primary pneumococcal peritonitis: description of a case and review of the literature]

Streptococcus pneumoniae causes lobar pneumonitis but primary peritonitis can occur in cyrrotic adults as well as in children affected by nephrosis and immunopathies. In young females peritonitis can be the consequence of infection localized at genital organs. Pneumococcal sepsis is becoming rare with the antibiotic era but resistance to penicillin is actually frequent and is becoming a problem for elderly. We report a case of a young woman affected by spontaneous primary peritonitis and pneumococcal sepsis. The prevalent symptoms were gastrointestinal: diarrhea and emesis. No infectious foci could be detected on imaging studies and during surgery.

Immunomodulatory effects of fusarochromanones TDP-1 and TDP-2

An in vitro peripheral lymphocyte blastogenesis system was used to investigate the biological activities of the fungal toxin fusarochromanone (TDP-1) and its monoacetyl derivative TDP-2. Briefly, cultures of human or bovine peripheral lymphocytes were exposed to TDP-1 or TDP-2 and a mitogen (PHA, Con A or PWM). After a standard incubation time, cell proliferation was quantified using the MTT bioassay. Human and bovine lymphocyte proliferation was inhibited by high concentrations of TDP-1; however, bovine lymphocyte proliferation was significantly increased at low concentrations of TDP-1. TDP-2 has similar but less pronounced effects on lymphocyte proliferation.

In vitro neutralization of T-2 toxin toxicity by a monoclonal antibody

A T-2 toxin specific monoclonal antibody, IgG1 K, with a low level of ELISA cross-reactivity to Acetyl T-2, HT-2, and iso T-2 toxins has been produced. The ability of this monoclonal antibody to neutralize the cytotoxicity of T-2 toxin in PHA stimulated cultures of human lymphocytes was determined by the MTT method. The complete neutralization of the toxic effect of 0.02 microM T-2 toxin was obtained with 0.03 microM of MoAb, whereas the 50% neutralizing dose (ND50) was observed at 0.009 microM of MoAb. Partial neutralization was observed with Acetyl T-2 toxin (ND50 = 0.038 microM) and HT-2 (ND50 = 0.94 microM). These results could represent a rational for clinical use of T-2 toxin specific monoclonal antibody in prophylaxis and therapy of T-2 toxemia.

In vitro vomitoxin exposure alters IgA and IgM secretion by CH12LX B cells. Relationship to proliferation and macromolecular synthesis

The CH12LX cell line was used as a clonal model to assess the direct effects of vomitoxin on IgM and IgA secretion in B cells. When vomitoxin was included in LPS-driven CH12LX B cell cultures, it had multiple effects on Ig secretion. Whereas vomitoxin doses of 115 and 120 ng/ml caused 50% inhibition (ID50) of IgA and IgM production, respectively, toxin concentrations in the 5 to 50 ng/ml range slightly stimulated IgA production. However, low vomitoxin doses did not induce switching of membrane IgM+ CH12LX B cells to membrane IgA+. Total cell number was unaffected at vomitoxin concentrations up to 100 ng/ml but dropped markedly at 200 ng/ml (ID50 = 170 ng/ml). Using the MTT reduction assay as another measure of viability and cell function, vomitoxin was also inhibitory (ID50 = 130 ng/ml). Both thymidine incorporation and leucine incorporation were also inhibited by the toxin with estimated ID50s being 120 and 110 ng/ml, respectively. The results indicate that although at high doses, vomitoxin inhibits proliferation, Ig secretion and DNA/protein synthesis in the clonal B cell model, the toxin marginally stimulated IgA secretion at lower doses.

Treatment of chronic hepatitis C with recombinant interferon alfa-2b

In a study of 87 patients with chronic hepatitis C, 12 months' treatment with interferon alfa-2b at a dose of 6 million units (MU) three times per week seemed to be more effective than treatment with 3 MU three times a week for two months plus 1.5 MU three times a week for 10 months in increasing the percentage of long term responders. The percentage of patients in whom alanine amino-transferase activities returned to normal was highest in the 6 MU group, as was the percentage of responders who sustained this normal activity after treatment. Side effects were moderate and self-limited in most patients.

Toxicity of some Fusarium section Sporotrichiella strains in relation to mycotoxin production

The relationship between the toxicities of crude extracts and purified toxins of Fusarium spp. belonging to the section Sporotrichiella has been assessed. Toxicity was determined on the basis of death of Artemia salina larvae and of viability and blastogenic response of bovine and human lymphocytes. Trichothecene-producing strains of Fusarium sporotrichioides and Fusarium poae were toxic to A. salina and to lymphocyte blastogenesis. A strain of Fusarium tricinctum, producing visoltricin and chlamydosporol, induced differentiated activity in different bioassays (toxicity to A. salina but only minor activity against lymphocyte blastogenesis). Other, non-toxin-producing strains of Fusarium chlamydosporum, F. poae, and F. tricinctum were not active in the tested biosystems.

Cytotoxic and immunotoxic effects of Fusarium mycotoxins using a rapid colorimetric bioassay

A colorimetric MTT (tetrazolium salt) cleavage test was used to evaluate cytotoxicity of twenty-three Fusarium mycotoxins on two cultured human cell lines (K-562 and MIN-GL1) as well as their inhibitory effect on proliferation of phytohemagglutinin-stimulated human peripheral blood lymphocytes. The values of 50% inhibition of lymphocyte blastogenesis were very close to the 50% cytotoxic doses observed with the more sensitive cell line (MIN-GL1). T-2 toxin was the most cytotoxic with CD50 and ID50 values less than 1 ng/ml. Type A trichothecenes were the most cytotoxic followed by the type B trichothecenes; the non-trichothecenes were the least cytotoxic. The MTT cleavage test, in conjunction with cell culture, is a simple and rapid bioassay to evaluate cytotoxicity and immunotoxicity of Fusarium mycotoxins.

Defective neutrophil mobilization to skin chambers in cancer patients

The in vivo migration of neutrophils was evaluated in patients affected by epithelial carcinoma using the quantitative skin-chamber technique. The results demonstrated a significant impairment of the patients' neutrophil migration, which was reduced to approximately 4% of that of the controls. Patients' sera were able to inhibit the chemotactic responsiveness of normal neutrophils in vitro. It is therefore suggested that the defective in vivo migration of neutrophils in cancer patients is related to the presence of humoral cell-directed inhibitory activity. This defect of neutrophil function might contribute to the host-defense impairment of carcinoma patients.

Role of the oxidative metabolic burst in the antibody-dependent cellular cytotoxicity mediated by neutrophil polymorphonuclears

The purpose of the present study was to investigate the mechanisms by which neutrophil polymorphonuclears (PMN) mediate antibody-dependent cellular cytotoxicity (ADCC). Under experimental conditions which allow target cell phagocytosis, PMN were found to efficiently kill IgG-sensitized ox erythrocytes, as determined by the 51Cr release assay. Inhibition of the target cell ingestion by colchicine did not affect the PMN cytotoxic activity, suggesting that target cell phagocytosis does not represent an essential step in the PMN-mediated ADCC against erythrocytes. PMN from patients with Chronic Granulomatous Disease, who have defective oxidative metabolic burst, displayed an impaired ADCC activity, which was unaffected by changes in the phagocytic capacities induced by colchicine. The results indicate that, under the experimental conditions employed, both the intracellular and the extracellular target cell destruction by PMN involve oxygen-dependent mechanisms.

Disorders of neutrophil function in children with recurrent pyogenic infections

Ten patients with neutrophil dysfunctions and recurrent pyogenic infections, mainly of the skin middle-ear, and respiratory tract, are described. The most frequently affected functions were chemotaxis and bacterial killing. Pharmacologic restoration of functional defects was tried in all cases. Levamisole was given in two cases and ascorbic acid in the other eight cases. During a follow up of at least 18 months, seven patients showed a complete restoration of neutrophil function and a long-lasting clinical remission. One of the two patients with Chronic Granulomatous Disease has been free from infections for 1 year, despite persistent neutrophil dysfunction, while the other did not display consistent clinical improvement. Another patient, who was given ascorbic acid for a short period only due to non compliance, showed neither laboratory nor clinical improvement.