Inhibitor activity of Lactiplantibacillus plantarum LP5 on thermotolerant campylobacter with different biofilm-forming capacities

AIMS

To evaluate the biofilm-forming capacity of thermotolerant Campylobacter (TC) strains from poultry production and to analyse the inhibitory capacity of Lactiplantibacillus plantarum LP5 against TC on different materials.

METHODS AND RESULTS

Biofilm-forming capacity by Campylobacter jejuni and Campylobacter coli was analysed by cell adhesion in polystyrene plates. TC were classified as non-biofilm-forming (NBF, 1.3%), weak biofilm-forming (WBF, 68.4%), moderate biofilm-forming (MBF, 27.6%), and strong biofilm-forming (SBF, 2.7%). The inhibitory capacity of L. plantarum LP5 against TC was tested on stainless-steel, nylon, aluminium, and glass disks (treated group) and compared with biofilm-forming TC (control group). Lactiplantibacillus plantarum LP5 was inoculated, and then TC. Biofilm was removed in both experimental groups and TC and LP5 bacterial counts were performed. The L. plantarum LP5 presence reduced the formation of TC biofilm (P < 0.001). The material type and strain category influenced biofilm formation, with stainless-steel and the SBF strain being the material and TC having the highest adhesion (P < 0.001). Lactiplantibacillus plantarum LP5 formed a similar biofilm on all materials (P = 0.823).

CONCLUSIONS

This trial showed very promising results; L. plantarum LP5 could be incorporated as a bio-protector of TC on different surfaces.

Lactic acid bacteria viability in different refrigerated food matrices: a systematic review and Meta‑analysis

The aim of this systematic review and meta-analysis was to determine which variables affect the viability of lactic acid bacteria (LAB) added to different types of refrigerated foods during the first 28 days. Scopus, ScienceDirect, PubMed and Cochrane Central Register of Reviews databases were searched from 1997 to April 2022. A total of 278 studies, which showed randomized and controlled experiments published in peer reviewed journals, were included. The viability of LAB in different moments during the storage process was synthesized as mean point estimate (MPE) via random-effects meta-analyses and the effect of multiple factors on the LAB´s viability was evaluated by multiple meta-regression. The meta-analysis showed that the decrease in LAB viability will be more abrupt the greater the initial dose. The physical structure of food may influence bacterial viability. Fruit was the type of product that most quickly lost viability. Co-culture of two or more species did not affect viability. Preservation methods had an unfavorable effect and prebiotics had a beneficial effect on bacterial viability. Viability was genus dependent. The data obtained in this study provide an overview of the factors to be taken into account for the design of new foods.

Molecular and Genetic Characterization of Colicinogenic Escherichia coli Strains Active against Shiga Toxin-Producing Escherichia coli O157:H7

The objective of this work was to molecularly and genotypically characterize and test the inhibitory activity of six colicinogenic Escherichia coli strains (ColEc) and their partially purified colicins against STEC O157:H7 isolated from clinical human cases. Inhibition tests demonstrated the activity of these strains and their colicins against STEC O157:H7. By PCR it was possible to detect colicins Ia, E7, and B and microcins M, H47, C7, and J25. By genome sequencing of two selected ColEc strains, it was possible to identify additional colicins such as E1 and Ib. No genes coding for stx1 and stx2 were detected after analyzing the genome sequence. The inhibitory activity of ColEc against STEC O157:H7 used as an indicator showed that colicins are potent growth inhibitors of E. coli O157:H7, being a potential alternative to reduce the presence of pathogens of public health relevance.

Communicating the Gynecologic Brachytherapy Experience (CoGBE): Clinician perceived benefits of a graphic narrative discussion guide

PURPOSE

Many current radiotherapy patient education materials are not patient-centered. An interprofessional team developed Communicating the Gynecologic Brachytherapy Experience (CoGBE), a graphic narrative discussion guide for cylinder, intracavitary, and interstitial high-dose-rate (HDR) gynecologic brachytherapy. This study assesses perceived clinical benefits, usability, and anxiety-reduction of CoGBE.

METHODS AND MATERIALS

An electronic survey was sent to members of the American Brachytherapy Society. Participants were assigned to assess one of the three modality-specific CoGBE versions using a modified Systems Usability Scale (SUS), modified state-trait anxiety index (mSTAI), and Likert-type questions. Free response data was analyzed using modified grounded theory.

RESULTS

Median modified SUS score was 76.3 (interquartile range [IQR], 71.3-82.5) and there were no significant differences between guide types. Median mSTAI was 40 (IQR, 40-43.3) for all guides collectively. The cylinder guide had a significantly higher median mSTAI than the intracavitary and interstitial guides (41.6 vs. 40.0 and 40.0; p = 0.04) suggesting the cylinder guide may have less impact on reducing anxiety. Most respondents reported that CoGBE was helpful (72%), would improve patient understanding (77%) and consultation memorability (82%), and was at least moderately likely to be incorporated into their practice (80%). Qualitative analysis themes included personalization and relatability (positive); generalizability (negative); illustrations (both).

CONCLUSIONS

Clinicians rate CoGBE as usable with potential to reduce patient anxiety, especially with more invasive treatment modalities including intracavitary or interstitial high-dose-rate. CoGBE has the potential to improve patient-clinician communication for a wider range of patients due to its accessible, adaptable, and patient-centered design.

Applicability of the probiotic Lactiplantibacillus plantarum BFL as an adjunct culture in a dry fermented sausage

The addition of probiotic bacteria to a meat batter allows the development of functional fermented sausages. The aim of this work was to study the effect of microencapsulated Lactiplantibacillus plantarum BFL (EP) and as free cells (FP) on microbiological, physicochemical, and sensory parameters of fermented sausages during the drying stage and on the product ready for consumption. The microencapsulation of L. plantarum BFL did not improve its viability during the drying stage. In addition, sausages inoculated with L. plantarum BFL (FP and EP) caused lower residual nitrites values, pH values and Escherichia coli counts than the Control (C). However, only the presence of free cells of L. plantarum BFL (FP) caused a decrease in the Enterobacteriaceae and mannitol salt-positive Staphylococcus counts. In the sensory analysis, no significant differences were found in the acceptability of the different sausages. However, the acidity in probiotic sausages (FP and EP) was an attribute that consumers highlighted. The probiotic L. plantarum BFL could adapt and survive at high doses in the matrix of an industrial fermented sausage. Therefore, its use could represent a strategy both for biocontrol of pathogens and for the development of functional meat products.

Relationship between Volatile Organic Compounds and Microorganisms Isolated from Raw Sheep Milk Cheeses Determined by Sanger Sequencing and GC-IMS

Recently, the interest of consumers regarding artisan cheeses worldwide has increased. The ability of different autochthonous and characterized lactic acid bacteria (LAB) to produce aromas and the identification of the volatile organic compounds (VOCs) responsible for flavor in cheeses are important aspects to consider when selecting strains with optimal aromatic properties, resulting in the diversification of cheese products. The objective of this work is to determine the relationship between VOCs and microorganisms isolated (Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Leuconostoc mesenteroides and Lactococcus lactis subsp. hordniae) from raw sheep milk cheeses (matured and creamy natural) using accuracy and alternative methods. On combining Sanger sequencing for LAB identification with Gas Chromatography coupled to Ion Mobility Spectrometry (GC−IMS) to determinate VOCs, we describe cheeses and differentiate the potential role of each microorganism in their volatilome. The contribution of each LAB can be described according to their different VOC profile. Differences between LAB behavior in each cheese are shown, especially between LAB involved in creamy cheeses. Only L. lactis subsp. hordniae and L. mesenteroides show the same VOC profile in de Man Rogosa and Sharpe (MRS) cultures, but for different cheeses, and show two differences in VOC production in skim milk cultures. The occurrence of Lactococcus lactis subsp. hordniae from cheese is reported for first time.

Gαi protein subunit: A step toward understanding its non-canonical mechanisms

The heterotrimeric G protein family plays essential roles during a varied array of cellular events; thus, its deregulation can seriously alter signaling events and the overall state of the cell. Heterotrimeric G-proteins have three subunits (α, β, γ) and are subdivided into four families, Gαi, Gα12/13, Gαq, and Gαs. These proteins cycle between an inactive Gα-GDP state and active Gα-GTP state, triggered canonically by the G-protein coupled receptor (GPCR) and by other accessory proteins receptors independent also known as AGS (Activators of G-protein Signaling). In this review, we summarize research data specific for the Gαi family. This family has the largest number of individual members, including Gαi1, Gαi2, Gαi3, Gαo, Gαt, Gαg, and Gαz, and constitutes the majority of G proteins α subunits expressed in a tissue or cell. Gαi was initially described by its inhibitory function on adenylyl cyclase activity, decreasing cAMP levels. Interestingly, today Gi family G-protein have been reported to be importantly involved in the immune system function. Here, we discuss the impact of Gαi on non-canonical effector proteins, such as c-Src, ERK1/2, phospholipase-C (PLC), and proteins from the Rho GTPase family members, all of them essential signaling pathways regulating a wide range of physiological processes.

DESARROLLO DE MODELO MURINO DE COLONIZACIÓN DE Lactobacillus plantarum LP5 DE ORIGEN PORCINO

The objective of this work was to generate an experimental model of colonization by L. plantarum LP5 in mice (Mus musculus) aimed at improving the general state of the animal and preventing the possible presence of zoonotic pathogens. The mice used were females of the Balb/cCmedc strain, 6 weeks old. Animals were organized into 2 groups of 3 individuals: treated (GT) and control (GC). GT was administered twice weekly by gavage with 100 µl of rifampicin resistant porcine L. plantarum LP5 at a concentration of 1010 CFU. Mice were fed water and food ad libitum throughout the experiment. Colonization in both groups was evaluated by the presence of clinical signs and by a microbiological analysis of the feces. Sampling was performed at weekly intervals to quantify the populations of the supplied L. plantarum LP5, Lactobacillus spp., Escherichia coli, total coliforms, Campylobacter and yeast. The results of the sampling in the GT in the week showed a recovery of L. plantarum LP5 above 5 logUFC/g, in the second it was 7 logUFC/g and in the third it was 5 logUFC/g. The CG, meanwhile, maintained the null count throughout the experiment. The results showed that there was no imbalance between the microbial components. Therefore, it is feasible to affirm that the inoculum did not alter the balance of the intestinal ecosystem. Particularly, it did not exert an inhibitory effect on the members of the previously established microbiota.

EFECTO INHIBITORIO DE Lactobacillus plantarum AISLADOS DESDE LAS DISTINTAS ETAPAS DE LA CADENA PRODUCTIVA DE CARNE PORCINA FRENTE A Campylobacter coli

Lactobacillus plantarum has a great capacity to adapt to environmental and have antibacterial capacity against different pathogen. This is a potential alternative for the control of pathogen in food coming slaughter animal. The objective of this work was to determine the antibacterial effect of L. plantarum strains against C. coli strains. L. plantarum LP1, LP3, LP5 and LP7 of porcine origin and a reference strain of Campylobacter coli NCTC 11366 were used. C. coli and L. plantarum was reactivated. Lyophilized ELC and ELCn were obtained. C. coli was distributed on the surface of mCCDA by swab and the ELC and the ELCn were inoculated in wells previously made on the agar. After 48 h, the diameter of the zone of inhibition was measured. The inhibition halos produced were 23.2 mm. The ELCn showed less antagonistic activity. The LP5 ELC generated higher inhibition halos and ELCn showed no differences between the four strains studied. L. plantarum strains, isolated from the pig production chain, could potentially be applied to control C. coli. This data is added to the scarce scientific evidence of the inhibitory effect of L. plantarum before this zoonotic pathogen of importance in public health.

Protective effect of Lactiplantibacillus plantarum LP5 in a murine model of colonisation by Campylobacter coli DSPV458

Thermotolerant Campylobacter species are the leading cause of foodborne bacterial diarrheal disease worldwide. Campylobacter coli, abundant in pigs and pork products, have been identified as a source of human infection. In this study, we propose the use of Lactiplantibacillus plantarum LP5 as a probiotic to reduce colonisation of this intestinal pathogen in a murine colonisation model of C. coli DSPV458. Six-week-old adult female Balb/cCmedc mice were housed in groups: Control, Campy and Pro-Campy. Control and Pro-Campy groups received antibiotics for 5 days and the Campy group for 12 days. Pro-Campy group was inoculated for 7 days with 8.78 log₁₀ cfu total of L. plantarum LP5 suspended in De Man, Rogosa and Sharpe broth. All groups were inoculated with 6.72 log₁₀ cfu of C. coli DSPV458 suspended in brain heart infusion broth. L. plantarum LP5 was recovered only in the Pro- Campy group. C. coli DSPV458 was recovered at higher levels in the Control and Campy groups. The differences with the Pro-Campy group were significant. As regards faeces, Control and Campy groups reached 7.41 and 7.84 log₁₀ cfu/g, respectively, and the Pro-Campy group only 4.62 log₁₀ cfu/g. In the caecum, Control and Campy groups reached 8.01 and 9.26 log₁₀cfu/g, respectively, and the Pro-Campy group only 4.51 log₁₀ cfu/g. In the ileum, Control and Campy groups reached 3.43 and 3.26 log₁₀ cfu/g, respectively, and the Pro-Campy group did not show detectable levels. The reduction of C. coli DSPV458 in the Pro-Campy group compared to the Control group in faeces, caecum and ileum was 99.55, 99.98 and 100%, respectively. Animals were maintained under normal health conditions, and haematological parameters were within the standard values for Balb/cCmedc. The incorporation of a probiotic generated a protective effect in the mice colonisation model. The protective effect would also apply to intestinal colonisation by indigenous enterobacteria. Therefore, the strategy used in this study is of great importance to understand the protection mechanisms in a murine model, as well as its application in food-producing animals.

Multi-mycotoxin occurrence in feed, metabolism and carry-over to animal-derived food products: A review

The world requests for raw materials used in animal feed has been steadily rising in the last years driven by higher demands for livestock production. Mycotoxins are frequent toxic metabolites present in these raw materials. The exposure of farm animals to mycotoxins could result in undesirable residues in animal-derived food products. Thus, the potential ingestion of edible animal products (milk, meat and fish) contaminated with mycotoxins constitutes a public health concern, since they enter the food chain and may cause adverse effects upon human health. The present review summarizes the state-of-the-art on the occurrence of mycotoxins in feed, their metabolism and carry-over into animal source foodstuffs, focusing particularly on the last decade. Maximum levels (MLs) for various mycotoxins have been established for a number of raw feed materials and animal food products. Such values are sometimes exceeded, however. Aflatoxins (AFs), fumonisins (FBs), ochratoxin A (OTA), trichothecenes (TCs) and zearalenone (ZEN) are the most prevalent mycotoxins in animal feed, with aflatoxin M₁ (AFM1) predominating in milk and dairy products, and OTA in meat by-products. The co-occurrence of mycotoxins in feed raw materials tends to be the rule rather than the exception, and the carry-over of mycotoxins from feed to animal source foods is more than proven.

Murine colonization model by Campylobacter coli DSPV458

AIMS

To generate a murine experimental model of colonization by Campylobacter coli DSPV458.

METHODS AND RESULTS

Twelve adult Balb/cCmedc female mice were housed in a treated group (T-G) and a control group (C-G) for 4 weeks. Both experimental groups received antibiotics for 5 days during the first week. The T-G was administered with 6.68log₁₀ CFU of C. coli DSPV458 by oesophageal gavage. Necropsies were performed weekly to evaluate translocation and intestinal colonization in the spleen and liver and in the ileum and cecum respectively. Samples were cultured to quantify intestinal microbiota members. Faeces were cultured weekly for a C. coli DSPV458 count. Campylobacter coli DSPV458 was isolated from all the inoculated mice. The recovered level of C. coli DSPV458 was, on average, 6.9 log₁₀ CFUg^-1 , 8.0 log₁₀ CFUg^-1 and 1.6 log₁₀ CFUg^-1 in faeces, cecum and ileum respectively. Colonization by C. coli DSPV458 does not alter the normal clinical and physiological status.

CONCLUSIONS

Campylobacter coli DSPV458 does not have an invasive capacity, and the model is suitable for evaluating strategies to reduce intestinal loads.

SIGNIFICANCE AND IMPACT OF STUDY

Farm animals have an important impact on thermotolerant Campylobacter transmission to humans. Extremely few colonization models by C. coli have been reported to date. In food-producing animals, infection is mild or absent and thermotolerant Campylobacter colonize the intestines of animals. Colonization models are specific models that do not cause infection as they do not generally result in diarrhoea or other signs of disease. Therefore, this model will allow to evaluate the evolution of colonization by thermotolerant Campylobacter and the alternative tools development to antibiotics that limit their colonization in food-producing animals.

P–398 Decidualization inhibits the expression of CXCR3-binding chemokines by human decidual stromal cells. Role in maternal-fetal immune tolerance

Study question

We aimed to analyze the effects of decidualization on the expression of chemokines that attract abortogenic T cells by human DSCs.

Summary answer

Decidualization inhibits the expression of chemokines that attract Th1 and Tc1 cells by DSCs, thereby preventing the arrival of abortogenic T cells into the decidua.

What is known already

Decidual stromal cells (DSCs) are the most abundant cells in the human decidua, the tissue that constitutes the maternal component of the placenta. Numerous evidences confirm that DSCs play a key role in maternal-fetal immune tolerance. In normal pregnancy, DSCs undergo a process of differentiation (decidualization) under the effect of progesterone and other pregnancy hormones. Decidualized DSCs become rounded and secrete prolactin, IL–15 and other factors. In the mouse, it has been observed that during pregnancy, DSCs inhibit the expression of chemokines that attract abortogenic Th1 and Tc1 cells from blood to the decidua.

Study design, size, duration

We compared the expression of CXCR3-binding chemokines by undifferentiated and decidualized human DSCs. We also compared the capacity of these cells to attract activated Th1 and Tc1 cells in vitro. Ten DSC lines were obtained from elective vaginal terminations of first-trimester pregnancies (6–11 weeks). Donors were healthy women aged 20–30 years. Informed consent was obtained from each donor. This study was approved by the Research and Ethics Committee of the University of Granada.

Participants/materials, setting, methods

Decidual stromal cell lines were established as previously described. These lines were decidualized with progesterone and cAMP in vitro. The expression of chemokines by these cells was studied by RT-PCR. Peripheral blood lymphocytes were activated with PHA, anti-CD28 and IL–2. As a consequence of this activation, CXCR3+ Th1 and Tc1 cells were produced. We used a migration assay in Transwell chambers to study the capacity of DSCs to attract these activated T cells.

Main results and the role of chance

We observed that those chemokines that bind to CXCR3, a chemokine receptor detected in activated Th1 and Tc1 cells, were not expressed by either undifferentiated and decidualized DSCs (CXCL9) or their expression was inhibited in decidualized DSCs (CXCL10 P &lt; 0.01, CXCL11 P &lt; 0.05). We found that conditioned media of undifferentiated DSCs decreased the migration of CXCR3+ activated T cells (Th1 and Tc1 cells) (P &lt; 0.05), and this effect was even stronger with conditioned media of decidialized DSCs P &lt; 0.001). These results demonstrated that decidualization of DSCs during pregnancy inhibits the expression of chemokines that attract Th1 and Tc1 cells by DSCs, thereby preventing the arrival of abortogenic T cells into the decidua.

Limitations, reasons for caution

This is an in vitro study due to the impossibility of performing an in vivo study in humans for ethical reasons.

Wider implications of the findings: Several publications have shown that DSCs have a therapeutic effect in various Th1-associated diseases. Our results explain this effect and suggest the extension of the use of these cells in the treatment of this type of diseases.

Trial registration number

Not applicable

Abstract 105: Communicating the Gynecologic Brachytherapy Experience (CoGBE): Clinician Perceived Benefits of a Graphic Narrative Patient Education Tool

Purpose: Radiotherapy patient education materials fail to meet readability standards, impairing access for patients with low educational attainment, disabilities, or limited-English proficiency. Design professionals and physicians developed graphic narrative discussion guides, Communication of the Gynecologic Brachytherapy Experience (CoGBE), for cylinder, intracavitary, and interstitial high-dose rate (HDR) gynecologic brachytherapy. This study assesses perceived clinical benefits, usability, and anxiety-reduction of CoGBE.

Methods: An electronic survey was sent to members of the American Brachytherapy Society. Participants were assigned to assess one of the three modality-specific CoGBE guides using a modified Systems Usability Scale (mSUS), modified state-trait anxiety index (mSTAI), and Likert-type questions. Free response data was analyzed using modified grounded theory.

Results: Median mSUS score was 76.3 (interquartile range [IQR], 71.3-82.5) and there were no significant differences between guide types. Median mSTAI was 40 (IQR, 40-43.3) for all guides collectively. The cylinder guide had a significantly higher median mSTAI than the intracavitary and interstitial guides (41.6 vs 40.0 and 40.0; p=0.04) suggesting the cylinder guide may have less impact on reducing anxiety. 72.7% rated CoGBE as “quite” or “extremely” helpful compared to a text-only pamphlet. When compared to their current education practices, 77.3% reported patients would understand “more” or “a lot more” after initial consultation and 81.8% reported CoGBE would be at least moderately helpful in making initial consultations more memorable for patients. Lastly, 79.5% reported at least a moderate likelihood of using CoGBE. Qualitative analysis themes included personalization, relatability, and graphic narrative (positive domains); generalizability and character affect (negative domains).

Conclusion: Clinicians rate CoGBE as usable with potential to reduce patient anxiety, especially with more invasive treatment modalities including intracavitary or interstitial HDR. The CoGBE guides (including multilingual versions) have global applicability, in low resource settings with high cervical cancer burdens and patient populations that may benefit from the graphic narrative format.

Citation Format: Santiago Avila, María J. Ruiz, Ritu Arya, Brian Callender, Yasmin Hasan, Josephine S. Kim, Nita Lee, Anne McCall, Christina H. Son, Kate Stack, Sabah Asif, Tyler Besecker, Arushi Juneja, Zhongyang Li, Pinakee Naik, Tanvi Ranka, Prachi Saxena, Brian Siegfried, Tomoko Ichikawa, Daniel W. Golden. Communicating the Gynecologic Brachytherapy Experience (CoGBE): Clinician Perceived Benefits of a Graphic Narrative Patient Education Tool [abstract]. In: Proceedings of the 9th Annual Symposium on Global Cancer Research; Global Cancer Research and Control: Looking Back and Charting a Path Forward; 2021 Mar 10-11. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2021;30(7 Suppl):Abstract nr 105.

In vitro screening and in vivo colonization pilot model of Lactobacillus plantarum LP5 and Campylobacter coli DSPV 458 in mice

The objective of this work was to determine the antibacterial effect of Lactobacillus plantarum strains of pork origin against Campylobacter coli strains, and to conduct experimental colonization pilot models in mice for both microorganisms. Inhibition assays allowed evaluation and selection of L. plantarum LP5 as the strain with the highest antagonistic activity against C. coli and with the best potential to be used in in vivo study. Adult 6-week-old female Balb/cCmedc mice were lodged in two groups. The treated group was administered with 9.4 log₁₀CFU/2 times/wk of L. plantarum LP5. L. plantarum LP5 was recovered from the feces and cecum of the inoculated mice. However, when bacteria stopped being administered, probiotic counts decreased. Experimental colonization with C. coli was carried out in five groups of mice. All animals were treated with antibiotics in their drinking water to weaken the indigenous microbiota and to allow colonization of C. coli. Four groups were administered once with different C. coli strains (DSPV458: 8.49 log₁₀CFU; DSPV567: 8.09 log₁₀CFU; DSPV570: 8.46 log₁₀CFU; DSPV541: 8.86 log₁₀CFU, respectively). After 8 h, mice inoculated with different C. coli strains were colonized because the pathogen was detected in their feces. L. plantarum LP5 tolerated the gastrointestinal conditions of murine model without generating adverse effects on the animals. C. coli DSPV458 colonized the mice without causing infection by lodging in their digestive tract, thus generating a reproducible colonization model. Both models combined could be used as protection murine models against pathogens to test alternative control tools to antibiotics.

Bioinformatic analysis of post-transmission viral readaptation in Argentine patients with acute HIV-1 infection

During the acute phase of HIV-1 infection, a strong readaptation occurs in the viral population. Our objective was to analyze the post-transmission mutations associated with escape to the cytotoxic immune response and its relationship with the progression of the infection. In this study, a total of 17 patients were enrolled during acute/early primary HIV infection and 8 subjects that were the HIV positive partner resulting in 8 transmission pairs. Genotyping of the genetic polymorphisms of HLA class I A and B was performed using PCR-SSOP. Viral RNA extraction was from plasma. 570 single Gag-gene amplifications were obtained by limiting-dilution RT-PCR. Epitope prediction was performed with NetMHC CBS prediction server for the 19 HLA-A and B alleles. Cytotoxic response prediction was performed by using the IEDB Analysis Resource. From our results, we deduce that the transmitted CTL / gag escape frequency in the founder virus was at least double compared to the post-transmission events. Additionally, by means of an algorithm that combines these frequencies, we observed that the founder viruses better adapted to the HLA A / B alleles of the recipient could contribute to a greater progression of the infection. Our results suggest that there is a large adaptation of HIV-1 to the HLA A / B alleles prevalent in our population. However, despite this adaptive advantage, the virus needs to make "readjustments" through new escape and compensatory mutations. Interestingly, according to our results, this readaptation could have a role in the progression of the infection.

Yeast derivatives and wheat germ in the adult diet modulates fecundity in a tephritid pest

Anastrepha fraterculus (Wiedemann), a pest of great economic importance in South America, needs urgently to be controlled by environmentally friendly methods such as the sterile insect technique for which mass rearing of insects is required. Because oogenesis takes place during the adult stage, mass-rearing facilities should provide the females a diet that maximizes egg production at the lowest cost. Accordingly, we investigated the effect of artificial protein sources in the adult diet (yeast derivatives of different cost but with similar amino acids profiles, and the addition of wheat germ) on fecundity. Additionally, we evaluated different ratios of yeast derivatives or wheat germ on ovary maturation, fecundity, and fertility as well as their association with the nutrient content of females. Females fed hydrolyzed yeast and yeast extract attained the highest fecundity level, and those fed brewer's yeast the lowest. Reducing the amount of hydrolyzed yeast, an expensive protein source, in the diet negatively affected fecundity and ovary maturation. Increasing the amount of brewer's yeast, a low-cost protein source, did not favor fecundity. The addition of wheat germ in the adult diet improved fecundity regardless of the yeast derivate considered. Percentage of egg hatch was not affected by the diet. Nutrient content of A. fraterculus females varied according to the adult diet provided and mating status. Our findings provide novel baseline information to understand the role of nutrition on reproductive performance of A. fraterculus females and are discussed in the context of resource allocation. They also provide valuable advances in the search for cost-effective adult diets at fruit fly mass rearing facilities.

Detection and Characterization of Salmonella Serotypes in the Production Chain of Two Pig Farms in Buenos Aires Province, Argentina

The aim of the present study was to determine the prevalence of Salmonella in the pork production chain and to characterize Salmonella isolates. From 764 samples, 35 (4.6%) were positive for Salmonella spp., as determined by biochemical tests and the presence of the invA gene. From these, 2.6, 2.0, 8.8, and 8.0% corresponded to samples collected from farms, slaughterhouses, boning rooms and retail markets, respectively. Salmonella strains were classified into five serotypes and distributed as follows: S. Typhimurium in the pork production chain, S. Kentucky in farms and slaughterhouses, S. Brandenburg in slaughterhouses, S. Livingstone in farms and S. Agona in boning rooms and retail markets. Interestingly, the antimicrobial susceptibility testing indicated that all 35 Salmonella spp.-positive isolates were resistant to at least one antimicrobial agent, and 30 were multidrug-resistant (MDR) and resistant to different classes of antibiotics. The enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) analysis showed clonal relatedness among strains isolated from farms, boning rooms and retail markets. The presence of antibiotic-resistant Salmonella in food poses a potential health hazard to consumers.

[Inhibitory capacity of Lactobacillus spp. against pathogens involved in foodborne diseases]

The genus Lactobacillus daily generates a growing interest among microbiologists and technologists, who try to discover new biotechnological applications and probiotic properties. The main goal of this study was to evaluate the inhibitory capacity of Lactobacillus spp. against pathogens (Escherichia coli O157:H7, Salmonella spp., Staphylococcus aureus) involved in foodborne diseases. For this purpose, samples were collected at different stages of the pork production chain. Seventy eight bacterial strains were isolated. Twenty seven (27) of these strains (37.18%) had genotypic and phenotypic characteristics corresponding to Lactobacillus spp. whereas 85.18% of them showed inhibitory capacity. These data showed that the studied strains represent a potential alternative to inactivate foodborne pathogens and thus provide safe food to consumers.

Reaction of zearalenone and α-zearalenol with allyl isothiocyanate, characterization of reaction products, their bioaccessibility and bioavailability in vitro

This study investigates the reduction of zearalenone (ZEA) and α-zearalenol (α-ZOL) on a solution model using allyl isothiocyanate (AITC) and also determines the bioaccessibility and bioavailability of the reaction products isolated and identified by MS-LIT. Mycotoxin reductions were dose-dependent, and ZEA levels decreased more than α-ZOL, ranging from 0.2 to 96.9% and 0 to 89.5% respectively, with no difference (p⩽0.05) between pH 4 and 7. Overall, simulated gastric bioaccessibility was higher than duodenal bioaccessibility for both mycotoxins and mycotoxin-AITC conjugates, with duodenal fractions representing ⩾63.5% of the original concentration. Simulated bioavailability of reaction products (α-ZOL/ZEA-AITC) were lower than 42.13%, but significantly higher than the original mycotoxins. The cytotoxicity of α-ZOL and ZEA in Caco-2/TC7 cells was also evaluated, with toxic effects observed at higher levels than 75μM. Further studies should be performed to evaluate the toxicity and estrogenic effect of α-ZOL/ZEA-AITC.

From Farm to Table: Follow-Up of Shiga Toxin-Producing Escherichia coli Throughout the Pork Production Chain in Argentina

Pigs are important reservoirs of Shiga toxin-producing Escherichia coli (STEC). The entrance of these strains into the food chain implies a risk to consumers because of the severity of hemolytic uremic syndrome. This study reports the prevalence and characterization of STEC throughout the pork production chain. From 764 samples, 31 (4.05%) were stx positive by PCR screening. At farms, 2.86% of samples were stx positive; at slaughter, 4.08% of carcasses were stx positive and at boning rooms, 6% of samples were stx positive. These percentages decreased in pork meat ready for sale at sales markets (4.59%). From positive samples, 50 isolates could be characterized. At farms 37.5% of the isolates carried stx1/stx2 genes, 37.5% possessed stx2e and 25%, carried only stx2. At slaughter we detected 50% of isolates positive for stx2, 33% for stx2e, and 16% for stx1/stx2. At boning rooms 59% of the isolates carried stx1/stx2, 14% stx2e, and 5% stx1/stx2/stx2e. At retail markets 66% of isolates were positive for stx2, 17% stx2e, and 17% stx1/stx2. For the other virulence factors, ehxA and saa were not detected and eae gene was detected in 12% of the isolates. Concerning putative adhesins, agn43 was detected in 72%, ehaA in 26%, aida in 8%, and iha in 6% of isolates. The strains were typed into 14 E. coli O groups (O1, O2, O8, O15, O20, O35, O69, O78, O91, O121, O138, O142, O157, O180) and 10 H groups (H9, H10, H16, H21, H26, H29, H30, H32, H45, H46). This study reports the prevalence and characterization of STEC strains through the chain pork suggesting the vertical transmission. STEC contamination originates in the farms and is transferred from pigs to carcasses in the slaughter process and increase in meat pork at boning rooms and sales markets. These results highlight the need to implement an integrated STEC control system based on good management practices on the farm and critical control point systems in the food chain.

Toxic effect of citrus peel constituents on Anastrepha fraterculus Wiedemann and Ceratitis capitata Wiedemann immature stages

The toxicity of essential oils from the citrus peel has been proposed as the major resistance mechanism offered by citrus to fruit fly infestation. We evaluated the insecticidal activity of the ether extracts from the lemon (Citrus limon [L.] Burm.) and grapefruit (C. paradisi Macfadyen) peel as well as from limonene and citral against Anastrepha fraterculus (Wiedemann) and Ceratitis capitata (Wiedemann) immature stages. We also evaluated the toxicity of the extracts at two ripening stages. Extracts proved toxic to A. fraterculus egg and larvae. The lemon and grapefruit extracts showed the same toxicity in both fruit fly species. For A. fraterculus eggs, citral was more toxic than limonene; for larvae, they showed equal toxicity. Anastrepha fraterculus eggs were more sensitive than C. capitata eggs. In conclusion, we provide evidence of chemical resistance mechanisms that could account for the nonhost condition of lemon for A. fraterculus.

Reactive oxygen species involvement in apoptosis and mitochondrial damage in Caco-2 cells induced by enniatins A, A₁, B and B₁

The cytotoxic effects, the generation of reactive oxygen species (ROS) and lipid peroxidation (LPO) as well as the cell cycle disruption, the induction of apoptosis and changes in mitochondrial membrane potential (ΔΨm) as a function of increasing time have been determined in human colorectal adenocarcinoma (Caco-2) cells after exposure to enniatins (ENs) A, A₁, B and B₁. IC₅₀ values obtained by the MTT and Neutral Red assay, after 24, 48 and 72 h of exposure ranged from 0.5±0.1 to >15 μM. A significant increase (p≤0.05) in ROS generation and LPO production, as determined by the fluorescent probe H2-DCFDA and TBARS method respectively, was observed for all mycotoxins tested at 3.0 μM concentration. The highest increase in ROS generation (2.6 fold higher than control) and LPO production (111%, as compared to control) was observed with EN A. Cell cycle was significantly arrested at G2/M phase after 24 h of exposure to EN A, A₁, B₁, whereas after 72 h of exposure an arrest in S phase was observed almost for all mycotoxins tested. Moreover, after 24 and 48 h of exposure, ENs increased the early apoptotic cells, whereas after 72h of exposure necrosis was observed. In addition the loss of ΔΨm was produced on Caco-2 cells after ENs exposure. ENs A, A₁, B and B₁ cytotoxicity involved early ROS generation that induced LPO oxidative damage, apoptosis and necrosis via the mitochondrial pathway. ENs A, A₁ and B₁ induced DNA damage. However the same effects cannot be proposed for EN B. Further studies on the toxicological effects induced by ENs A, A₁, B and B₁ are needed.

Effect of polyphenols on enniatins-induced cytotoxic effects in mammalian cells

Enniatins (ENs) are fungal secondary metabolites produced by genus Fusarium. The ENs exert antimicrobial and insecticidal effect, and has also been demonstrated cytotoxic effects on several mammalian cell lines. On the other hands, it has been proved that natural polyphenols have antioxidant effect. In this study, cell effects at low levels of exposure of four ENs (A, A(1), B and B(1)) and five polyphenols (quercetin, quercetin-3-β-D-glucoside, rutin, myricetin and t-pterostilbene) present in wine; and the cytoprotective effect of these polyphenols exposed simultaneously with ENs in Chinese Hamster Ovary (CHO-K1) cells, were studied. Cell effects were determined by the MTT test after 24 h of exposure. All ENs showed cytotoxic effect. The IC(50) obtained ranged from 4.5 ± 1.2 to 11.0 ± 2.7 µM. The concentration of polyphenols tested ranged from 5 to 50 µM. Polyphenols did not show cytotoxicity and the cytoprotective effect of polyphenols varies depending on the EN tested. The cytoprotective effect of polyphenols in CHO-K1 cells exposed to ENs was as follow: quercetin, from 24 to 84%; quercetin-3-β-D-glucoside, from 12 to 76%; rutin, from 17 to 83%; myricetin, from 16 to 92% and pterostilbene from 25 to 100%. All polyphenols protected CHO-K1 cells against EN A(1) exposure.

Management of protein intake in the fruit fly Anastrepha fraterculus

This work tested if carbohydrates and proteins ingestion is regulated in the South American fruit fly, Anastrepha fraterculus, to optimize survival and reproduction. Adult food treatments were established by providing sugar and hydrolyzed yeast in various combinations either alone or mixed at a standard 3:1 ratio (sugar:hydrolyzed yeast). Individual food consumption was assessed and related to survival patterns. The effects of adult feeding on fecundity and fertility patterns were investigated in groups of flies. Sugar consumption was the lowest in the treatment where it was provided with hydrolyzed yeast at a fixed 3:1 ratio. Consumption of hydrolyzed yeast did not differ between this treatment and the one in which this solution was complemented with one solution of sugar. It seems that a mixture of sugar and hydrolyzed yeast at a fixed ratio of 3:1, respectively, restricts extra ingestion of sugar; most probably because of negative response of the fly to overconsumption of protein. Survival was affected by the treatments, being lower in those cases where protein was at the fixed ratio. Group experiments revealed that protein restriction expanded longevity and decreased egg production. In contrast, egg production was enhanced when flies were kept continuously with a mixture of yeast and sugar plus an extra source of sugar, and this was not in detriment of survival. Our results suggest that fixed sugar-protein ratios in which protein is in excess affects fitness components such as longevity and reproduction. These findings are discussed from a theoretical and applied perspective in the context of pest control by means of the sterile insect technique.

Comparative cytotoxicity study of enniatins A, A₁, A₂, B, B₁, B₄ and J₃ on Caco-2 cells, Hep-G₂ and HT-29

Enniatins (ENs) are ionophoric, phytotoxic, antihelminthic, and antibiotic compounds of hexadepsipeptidic structure produced by several strains of Fusarium spp. The cytotoxicity effect of the ENs A, A(1), A(2), B, B(1), B(4) and J(3) was compared on three tumor cell lines, the human epithelial colorectal adenocarcinoma (Caco-2), the human colon carcinoma (HT-29), and the human liver carcinoma (Hep-G2). The endpoint evaluated was the mitochondrial integrity by using the MTT assays, after 24 and 48 h of incubation. The IC(50) value for EN A(2) on Caco-2 cells, after 24h exposure, was 18.7 ± 4.5 μM and decrease to 2.6 ± 0.7 μM at 48 h of incubation. However, ENs A, A(1), B(1) and B(4) exert pronounced cytotoxic effects in all the cell lines tested by the MTT assay after 24 and 48 h of incubation. The EN A(1) demonstrated to be the most cytotoxic ENs tested. Moreover, no statistical differences were found between the IC(50) values obtained for EN A(1) on Caco-2, HT-29 and Hep-G2, with IC(50) values ranging from 9.1 ± 2.2 μM to 12.3 ± 4.3 μM at 24h and decreasing in a range variable from 1.4 ± 0.7 μM to 2.7 ± 0.8 μM at 48 h. On the other hand, EN A, B(1) and B(4) showed lower cytotoxicity, but in a similar range as the IC(50) values reported on HT-29 (IC(50) values (24h): 16.8 ± 4.3-26.2 ± 6.7 μM), Caco-2 (IC(50) values (24h): 19.5 ± 4.1 μM) and Hep-G2 (IC(50) values (24h): 23.4 ± 5.6-26.2 ± 7.6 μM) cells. Cytotoxic effect with a 48 h of incubation revealed also a significant toxicity of ENs A (IC(50) values ranged from 8.2 ± 1.8 to 11.4 ± 4.6 μM), B(1) (IC(50) values variables from 3.7 ± 0.7 to 11.5 ± 5.3 μM) and B(4) (IC(50) of 4.5 ± 2.9-15.0 ± 4.0 μM). In summary, this study demonstrated that ENs can exert toxic activity at low micromolar concentrations in mammalian cells.

Spanish radiobiological pattern of care in lung cancer: a GOECP/SEOR study

INTRODUCTION

A survey regarding radiobiological questions in the treatment of lung cancer (LC) was done to study the clinical aspects of radiotherapy in Spain, in order to standardise treatment decisions.

METHODS AND MATERIALS

From November 2007 to March 2008, a survey was performed among radiation oncologists in Spain specialising in LC treatment via e-mail, which included questions regarding different radiobiological aspects of radiotherapy LC treatment. The extent of the resulting material made it necessary to divide it into two parts; the first is presented in this article. The second, which includes items about alpha/beta-NTCP/TCP values and reirradiation criteria, will be reported elsewhere.

RESULTS

Thirty-one radiation therapists from 29 radiation oncology departments answered the survey. 77.4-93.5% of responders used the basic formula from the linear-quadratic model and/or computer software for radiobiological calculations; 100% used lung (mostly V20, median <30%) and spinal cord constraints (mostly a median of physical maximum dose <45.5 Gy); and 90.3% used heart and oesophagus constraints (very heterogeneous parameters in both organs).

CONCLUSIONS

Radiobiological considerations are clearly present in the planning process of radiotherapy of LC in Spain, with a high coincidence with the literature regarding lung and spinal cord constraints. The heterogeneity shown for oesophagus and heart results demonstrates the need for continuing investigation into the standardisation of clinical, dosimetric and radiobiologic aspects of the treatment of this cancer.

Isolation and purification of enniatins A, A(1), B, B(1), produced by Fusarium tricinctum in solid culture, and cytotoxicity effects on Caco-2 cells

Enniatins (ENs) are antibiotic compounds of hexadepsipeptidic structure produced by several strains of Fusarium spp. The ENs A, A(1), B, B(1) were purified from extracts of Fusarium tricinctum grown on a solid medium of corn, by a low pressure liquid chromatography (LPLC) on reverse phase of Amberlite XAD-7 followed by semipreparative LC. The purity and the structure of the isolated compounds were confirmed by LC-MS/MS. The technique of the purification of the fungal extract enabled complete separation of the ENs A, A(1), B, B(1) with a mean purity of 97% for all the compounds. The cytoxicity of the ENs was tested in the cell lines of human origin (epithelial colorectal adenocarcinoma cells, Caco-2) by MTT assays. Only EN A(1) and B(1) evoked toxicity at the tested concentrations. The inhibitory concentration (IC(50)) for EN A(1) on Caco-2 cells was 12.3 microM, whereas the IC(50) produced by the EN B(1) was 19.5 microM. This study indicates that ENs, fungal metabolites that are commonly found in corn and in general in product composed by corn, may have a toxic potential for human health.

Dietary administration of high doses of pterostilbene and quercetin to mice is not toxic

The aim of this study is to evaluate possible harmful effects of high doses of t-pterostilbene (t-PTER) and quercetin (QUER) in Swiss mice. Mice were fed during 28 days at doses of 0, 30, 300, and 3000 mg/kg body weight/day of t-PTER, QUER, or a mixture of both, t-PTER + QUER, which are equivalent to 5, 50, and 500 times, respectively, the estimated mean human intake of these polyphenols (25 mg/day). Daily oral administration of QUER, t-PTER, or a mixture of both of them did not cause mortality during the experimental period. There were no differences in food and water consumption on sex. No significant body weight gain in the male or female groups was observed. Red blood cell number and the hematocrit increased after polyphenols administration compared to control groups. Biochemical parameters were not affected. Histopathological examination revealed no alterations in clinical signs or organ weight at any dose.

Exposure assessment of fruits contaminated with pesticide residues from Valencia, 2001- 03

A total of 634 samples of oranges, tangerines, peaches, nectarines, khakis and watermelons were collected from an Agricultural Valencia Community Cooperative during the May 2001 to April 2003 campaigns and they were analysed for 15 pesticides among those recommended for pest treatment. A conventional multiresidue analytical procedure based on ethyl acetate extraction was used followed by gas chromatography coupled to a nitrogen phosphorus detector for routine analysis; and mass spectrometry was performed for confirmation. Recovery studies with spiked samples at 0.5 mg kg-1 for each pesticide ranged from 52% for acephate to 87% for fenthion with a standard deviation <20%. Limits of quantification ranged from 0.1 to 100 microg kg-1. A total of 43% of samples contained pesticide residues; and 5% exceeded the maximum residue levels (MRLs). Nine of the pesticides studied were found. Malathion, which was the most frequently detected, was found in 121 samples (19%) at 0.002-4.25 mg kg-1; followed by fenthion in 104 samples (16%) at 0.005-2.3 mg kg-1; and methidation in 68 samples (10%) at 0.008-1.3 mg kg-1. Khaki showed the highest contamination rates with 60% of contaminated samples that exceeded more often the MRLs; and fenthion was the pesticide more frequently detected in all the commodities studied at levels above the European MRLs. The estimated daily intakes of each pesticide calculated from the results obtained were much lower than the acceptable daily intakes.

Determination of microcystins in natural blooms and cyanobacterial strain cultures by matrix solid-phase dispersion and liquid chromatography?mass spectrometry

An analytical procedure based on matrix solid-phase dispersion (MSPD) and liquid chromatography-mass spectrometry (LC-MS) was developed for determining three microcystins (MCs) in natural water blooms and cyanobacteria strain cultures. The procedure involves sample homogenization with C(18), washed with dichloromethane to eliminate interfering compounds, and elution with acidic methanol. Results were compared to those achieved by using an organic solvent standard method. Mean recoveries of MCs with MSPD were 85-92% with intra-day relative standard deviation (RSDs) of 9-19%, whereas organic solvent extraction resulted in recovery rates of 92-105% with intra-day RSDs ranging from 8 to 18%. Limits of quantification (LOQs) were 1 microg g(-1) dry weight for the MCs either by MSPD or organic solvent extraction. The two analytical methods tested were specific and sensitive to the extraction of MCs and were applied to the detection of MCs in water blooms and culture strains. The concentration of MCs varied from 7 to 3,330 microg g(-1) of lyophilized cells with MC-LR always showing the highest concentration. MCs levels were higher in culture strains than in water blooms, except for MC-LR, whose concentration in blooms was slightly superior to that determined in culture strains.

Serological response (Western blot) to fractions of Mycobacterium tuberculosis sonicate antigen in tuberculosis patients and contacts

OBJECTIVE

To assess the serological response to fractions of Mycobacterium tuberculosis sonicate antigen by Western blot analysis in patients with tuberculosis and contacts.

METHODS

We studied 71 individuals including 43 patients with active tuberculosis, 16 contacts and 12 healthy blood donors. For Western blot analysis, M. tuberculosis (H37Rv strain) sonicate antigen extract was fractionated by electrophoresis on polyacrylamide gel (SDS-PAGE).

RESULTS

We obtained antibody responses directed against four antigenic fractions with molecular weights of 71, 65, 26-38 and 19 kDa. Sixty per cent of pleural tuberculosis and 52.4% of smear-positive pulmonary tuberculosis had whole responses against all four fractions; there were no partial responses in these groups. For patients with smear-negative pulmonary tuberculosis whole responses were 17.6% and partial responses 41.2%. All contacts whose tuberculin tests converted from negative to positive (three cases) reacted exclusively against the 19 kDa fraction.

CONCLUSIONS

Western blot-positive results in patients with pleural and smear-positive pulmonary tuberculosis were characterised by a whole pattern against all four antigenic fractions, whereas patients with smear-negative pulmonary tuberculosis showed heterogeneous results. The exclusive response against the 19 kDa fraction observed in contacts with tuberculin conversion could help to identify candidates for preventive therapy.

Lack of significant cross-reactivity between Leishmania serology and mycobacteriosis in patients infected with HIV-1

OBJECTIVE: To determine the existence of cross-reactions between Leishmania serology and mycobacteriosis in patients infected with HIV-1. PATIENTS AND METHODS: HIV-positive individuals, with culture-proven episodes of tuberculosis or disseminated Mycobacterium avium complex (MAC) infection, were identified from the data files of our microbiology laboratory. Patients were included if leishmania serology had been performed within a period of 2 months before and 1 month after the diagnosis of mycobacterial disease. RESULTS: We identified 106 cases of tuberculosis and 38 of disseminated MAC infection with concomitant leishmania serology in HIV-infected individuals. Among them, only two cases (1.8%), both with tuberculosis and without visceral leishmaniasis, showed positive leishmania serology. The two cases are discussed. CONCLUSIONS: We conclude that, in spite of its low sensitivity, serology is a useful diagnostic tool in co-infected patients, mainly because of its high specificity and the low rate of cross-reactivity with two of the most frequent causes of fever of unknown origin in HIV-positive patients from our area.

Genotoxicity of six pesticides by Salmonella mutagenicity test and SOS chromotest

Two in vitro tests (Ames test and SOS chromotest), one for bacterial mutagenicity and one for primary DNA damage, were assayed to determine the genotoxic activity of 6 pesticides (atrazine, captafol, Captan, chlorpyrifosmethyl, molinate and tetrachlorvinphos). Assays were carried out both in the absence and presence of S9 fractions of liver homogenate from rat (Sprague-Dawley) pretreated with Aroclor 1254. Captan and captafol were genotoxic on both the Ames test and the SOS chromotest. Comparisons with mutagenesis data in Salmonella indicated that the SOS assay detected as genotoxic the pesticides that were mutagenic on the Salmonella test. Non-genotoxic effects were not detected in vitro either in the Salmonella/microsome assay nor in the SOS chromotest when bacterial tester strains were exposed to atrazine, molinate, chlorpyrifosmethyl and tetrachlorvinphos in the absence or presence of S9 mix.

Dissipation and distribution of atrazine, simazine, chlorpyrifos, and tetradifon residues in citrus orchard soil

An environmental fate study was conducted in a citrus orchard plot in València (Spain) in the fall of 1993. Dissipation and distribution of atrazine, simazine, chlorpyrifos and tetradifon residues following their controlled addition for agricultural purposes in a mediterranean red soil (Luvic Calcisol, Rhodoxeralf) were evaluated. During a two-month period, the amounts of applied pesticides in different soil layers (0-0.05, 0.05-0.22, 0.22-0.42, and 0.42-0.52 m) were monitored. In addition, information on soils, weather and agricultural practice were collected. Degradation half-lives were calculated, assuming zero-order kinetics: 11 days for atrazine, 12 days for simazine, 10 days for chlorpyrifos, and 18 for tetradifon. The distribution through the soil profile shows that the pesticide concentrations were always highest in the upper layer (0-0.05 m) of soil, and that atrazine was the most mobile of all the four pesticides investigated.

Dose-area product values in frequently performed complex paediatric radiology examinations

Mean values of the dose-area product for barium meal, micturating cystourethrography and intravenous urography examinations from three health centres and for four age groups are presented in this study. Values measured are between 13% and 86% higher than results previously reported, which justifies the importance of applying procedures which reduce risks to patients.

Radiation doses to paediatric patients undergoing micturating cystourethrography examinations and potential reduction by radiation protection optimization

Dose-area product values were measured in paediatric micturating cystourethrography examinations in two dedicated facilities. The results are compared, taking into account features of the X-ray rooms and differences in examination protocol. Several optimization procedures were simulated or implemented, in order to estimate the dose savings which could be attained. Potential savings identified in the dose-area values reach about 85% for both centres.

Image quality and patient dose for different screen-film combinations

Comparisons of image quality and estimations of dose reductions were made for several new screen-film combinations including conventional and rare-earth systems under conditions similar to abdomen radiography. The evaluation was carried out using an ANSI type phantom and the TOR(CDR) image quality object developed by the University of Leeds. The parameters employed for the comparison were: entrance dose, high and low contrast threshold sensitivity and resolution. The advantages and limitations of the method are also discussed. Results show that images with high quality can be obtained with comparatively low patient doses, and that there are still wide differences in image quality for similar speed systems, depending on the manufacturer and on the chosen combination.

[Bronchiolitis obliterans associated with organizing pneumonia. Clinico-pathological study of 6 cases]

Over the last three years six patients diagnosed of bronchiolitis obliterans with organizing pneumonia were studied. Diagnosis was established by open lung biopsy in 4 and by transbronchial lung biopsy in 2. The initiation of the symptoms was subacute although one patient evolved to respiratory failure requiring mechanical ventilation. The mean age of presentation was 68 years with male predominance over females of 5:1. The most frequent symptoms were fever and general malaise in 6 patients, cough and dyspnea in 4, respectively and weight loss in 2 patients. Functional respiratory tests showed restrictive ventilation disturbances in 4 out of 5 patients, mixed in 1 and a reduction in diffusion capacity in the 5 patients in whom it was determined. The radiologic pattern of multifocal alveolar infiltration was present in 6 cases. Interstitial involvement was also associated in 3 patients with pleural effusion in 2. Histologic findings of intraluminal polypoid masses affecting the bronchiols and alveolar conducts (bronchiolitis obliterants) with extension to the alveoli forming conjunctive Masson polyps (organizing pneumonia) was found in the 4 patients who underwent open lung biopsy and in 1 diagnosed by transbronchial biopsy although there were quantitative differences in the degree of alveolar involvement. Response to treatment with steroids was favorable in 5 out of 6 patients while the remaining patients spontaneously improved following thoracotomy.

Measurement of radiation doses in the most frequent simple examinations in paediatric radiology and its dependence on patient age

Radiation doses to patients were measured in four X-ray rooms specifically devoted to paediatric radiology, from two hospitals. The study was performed for the most frequent simple examinations, namely abdomen, hip and pelvis, skull, spine and chest. Patients were classed into four different age groups: 0.1-1 year, greater than 1-5 years, greater than 5-10 years and greater than 10-14 years. Operating X-ray generator parameters and entrance surface doses were recorded for all groups. Representative values were obtained for standard working conditions prior to any correcting action being taken. Dose values are reported, and some of the differences between the results found in the rooms for each examination are discussed. Without attempting to relate adult and paediatric radiology, the entrance surface doses measured and the provisionally recommended CEC values for similar examinations in adult patients are compared.

[Pleurodesis with tetracycline in neoplastic effusions. Is an acid pH necessary?]

Forty-three patients with recurrent malignant pleural effusions were included in a prospective protocol of treatment with two different types of tetracycline. Twenty-one patients (series A) were treated with a saline dilution of oxytetracycline (pH = 8) and twenty-two (series B) with a saline dilution of tetracycline chlorhydrate (pH = 2). Among the patients of series A, the rate of no recurrence of the effusion was 85.7% (12 out of 14 correctly treated and followed-up patients). In the series B, the rate of no recurrence was 86.6% (13 out of 15). The authors conclude that the pH of the tetracycline is not a determinant of pleural symphysis. The mechanism of action of the intrapleural tetracycline is discussed.

[Treatment of malignant pleural effusions]

The methods used to induce pleural symphisis in recidivant malignant pleural effusions are reviewed. The most suitable for an average hospital are the intrapleural introduction of talc and tetracycline clorhydrate, of which the procedures are described.