Graduate certificate on risk analysis for the Agrifood sector at the University of Buenos Aires

Argentina has an extensive experience in the biosafety assessment of transgenic crops. The regulatory framework celebrated 30 years of existence in 2021 and has pioneered the establishment of the biosafety systems in Latin America. During this period, Argentina's regulatory framework evolved to keep up with the advancements in plant and animal biotechnology and in risk assessment criteria, as new knowledge and experience was being gained. However, despite the country's agricultural tradition and experience in the adoption of innovations by the productive sector, dedicated, formal academic offerings training is lacking and this is also true for most countries in the world. Responding to this perceived need and going beyond biotechnology to include other regulated inputs used along the food production chain (chemicals, biologics, food additives, etc.), we developed a program to introduce graduates from diverse disciplines to the principles and practice of Risk Analysis (Assessment, Management and Communication) with focus on the Agrifood sector. In 2020, the School for Graduate Students of the School of Agriculture-University of Buenos Aires, approved two Certificates on Risk Analysis for the Agrifood Sector: Conceptual Bases of Risk Analysis and Methodological Tools. The first edition of the certificates was completed in December 2022 and the second one is presently ongoing. The fundaments, rationale, structure and objectives of these certificates are presented.

Familiarity in the Context of Risk Assessment of Transgenic Crops: Focus on Some Countries in the Americas

Problem formulation is the formal opening stage of a risk assessment that determines its purpose and scope and hence guides the gathering of information data. The concepts of familiarity and history of safe use are an integral part of problem formulation. These concepts do not replace the case-by-case approach and are not taken as safety standards but are valuable components of the process that shape the generation of plausible, testable risk hypotheses. The International Life Sciences Institutes in Brazil and Argentina have facilitated numerous discussions on the scientific principles for risk assessment of transgenic crops in the Latin American region in the past 5–6 years. The session held at ISBR 15th elaborated on the familiarity concept and derived tools and their role in the evolution of risk evaluation criteria. Examples of how different countries in the Americas interpret and apply these conceptual tools show that familiarity is a valuable concept, although terms are very often confused and vaguely defined. Formalizing these terms with clear definitions and scope of application in guidelines and regulatory documents would reduce ambiguity, enhance predictability, and add transparency to the evaluation processes.

Capacities for the Risk Assessment of GMOs: Challenges to Build Sustainable Systems

The need for functional risk assessment bodies in general, and in the biosafety field in particular, demands continued efforts and commitment from regulatory agencies, if results that are sustainable in time are to be achieved. The lack of formal processes that ensure continuity in the application of state of the art scientific criteria, the high rotation in some cases or the lack of experienced professionals, in others, is a challenge to be addressed. Capacity building initiatives with different approaches and degrees of success have been implemented in many countries over the years, supported by diverse governmental and non-governmental organizations. This document summarizes some capacity building experiences in developing countries and concludes that risk assessors taking ownership and regulatory authorities fully committed to developing and retaining highly qualified bodies are a sine qua non to achieve sustainable systems. To this end, it is essential to implement “in-house” continuing education mechanisms supported by external experts and organizations, and inter-institutional cooperation. It has to be noted that these recommendations could only be realized if policy makers understand and appreciate the value of professional, independent regulatory bodies.

Development of a construct-based risk assessment framework for genetic engineered crops

Experience gained in the risk assessment (RA) of genetically engineered (GE) crops since their first experimental introductions in the early nineties, has increased the level of familiarity with these breeding methodologies and has motivated several agencies and expert groups worldwide to revisit the scientific criteria underlying the RA process. Along these lines, the need to engage in a scientific discussion for the case of GE crops transformed with similar constructs was recently identified in Argentina. In response to this need, the Argentine branch of the International Life Sciences Institute (ILSI Argentina) convened a tripartite working group to discuss a science-based evaluation approach for transformation events developed with genetic constructs which are identical or similar to those used in previously evaluated or approved GE crops. This discussion considered new transformation events within the same or different species and covered both environmental and food safety aspects. A construct similarity concept was defined, considering the biological function of the introduced genes. Factors like environmental and dietary exposure, familiarity with both the crop and the trait as well as the crop biology, were identified as key to inform a construct-based RA process.

Proposed criteria for identifying GE crop plants that pose a low or negligible risk to the environment under conditions of low-level presence in seed

The low-level presence (LLP) of genetically engineered (GE) seeds that have been approved in the country of origin but not the country of import presents challenges for regulators in both seed importing and exporting countries, as well as for the international seed trade and the farmers who rely on it. In addition to legal, financial and regulatory challenges, such LLP situations in seed may also require an environmental risk assessment by the country of import. Such assessments have typically been informed by the national framework established to support decisions related to wide scale cultivation, and frequently do not take into account the low environmental exposure and prior regulatory history of the GE plant. In addition, such assessment processes may not be well suited to the decision-making timeframe that is necessary when dealing with an LLP situation in imported seed. In order to facilitate regulatory decision making, this paper proposes a set of scientific criteria for identifying GE crop plants that are expected to pose a low or negligible risk to the environment under LLP conditions in seed. Regulatory decision makers in some importing countries may decide to use these criteria to assist in risk analysis associated with LLP situations they are experiencing or could experience in the future, and might choose to proactively apply the criteria to identify existing GE plants with regulatory approvals in other countries that would be expected to pose low risk under conditions of LLP in seed.

Transportability of confined field trial data for environmental risk assessment of genetically engineered plants: a conceptual framework

It is commonly held that confined field trials (CFTs) used to evaluate the potential adverse environmental impacts of a genetically engineered (GE) plant should be conducted in each country where cultivation is intended, even when relevant and potentially sufficient data are already available from studies conducted elsewhere. The acceptance of data generated in CFTs "out of country" can only be realized in practice if the agro-climatic zone where a CFT is conducted is demonstrably representative of the agro-climatic zones in those geographies to which the data will be transported. In an attempt to elaborate this idea, a multi-disciplinary Working Group of scientists collaborated to develop a conceptual framework and associated process that can be used by the regulated and regulatory communities to support transportability of CFT data for environmental risk assessment (ERA). As proposed here, application of the conceptual framework provides a scientifically defensible process for evaluating if existing CFT data from remote sites are relevant and/or sufficient for local ERAs. Additionally, it promotes a strategic approach to identifying CFT site locations so that field data will be transportable from one regulatory jurisdiction to another. Application of the framework and process should be particularly beneficial to public sector product developers and small enterprises that develop innovative GE events but cannot afford to replicate redundant CFTs, and to regulatory authorities seeking to improve the deployment of limited institutional resources.

Fungal and mycotoxin contamination in Bt maize and non-Bt maize grown in Argentina

A Bt maize hybrid and its non-transgenic counterpart harvested during 2002/2003 and 2003/2004 harvest seasons from different locations within the maize-growing area in Argentina were compared for fungal and mycotoxin contamination. Fusarium species were the most prevalent on both genotypes with an isolation frequency >60% across all locations. The percentage of infection was lower in Bt maize than in non-Bt maize (P<0.05). There were no statistical differences in infection percentage due to genotype, fungicide treatment and their interactions. Fumonisins were detected in all of the samples from all locations and genotypes. Total fumonisin levels (fumonisins B1, B2 and B3) in the Bt and the non-Bt hybrid were significantly different (P<0.001), with lower toxin levels in the Bt maize in all locations but one evaluated during the two harvest season. There was no significant difference in deoxynivalenol levels between Bt and non-Bt maize. Application of the fungicide tebuconazole did not alter either the infection or the toxin levels in the Bt and non-Bt maize hybrid.

Factors associated with survival in patients with progressive disease following autologous transplant for lymphoma

Our objectives were to assess survival and predictors for survival among lymphoma patients whose disease had progressed after autologous bone marrow (ABMT) or stem cell transplantation (ASCT). Patients transplanted at Hadassah University Hospital between October 1983 and February 1999 were included. We compared survival of patients with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) after relapse or progression. Predictors for survival were assessed in a multivariate model. Of 88 transplanted patients with HD and 152 with NHL, relapse/progression occurred in 27 (31%) and 75 (49%), respectively. Median survival postrelapse was 25 months for HD and 7.5 months for NHL (P=0.12). Seven relapsed patients with HD (26%) and 10 (13%) with NHL survived >4 years. In NHL, longer postrelapse survival was associated with indolent histologies (P=0.007). On multivariate analysis, factors associated with survival included attainment of remission postrelapse (for both diseases), use of prophylactic immunotherapy (for HD), LDH level and time from transplant to relapse (for NHL). The short-term prognosis for patients with disease progression postautologous transplant may be somewhat better for HD compared to NHL. Long-term survival is poor in both diseases. However, the survival times in the current study are twice as long as those previously reported. Treatment regimens with the potential for achieving remission may have an impact on survival.

Characterization of Cyt2Bc toxin from Bacillus thuringiensis subsp. medellin

We cloned and sequenced a new cytolysin gene from Bacillus thuringiensis subsp. medellin. Three IS240-like insertion sequence elements and the previously cloned cyt1Ab and p21 genes were found in the vicinity of the cytolysin gene. The cytolysin gene encodes a protein 29.7 kDa in size that is 91.5% identical to Cyt2Ba from Bacillus thuringiensis subsp. israelensis and has been designated Cyt2Bc. Inclusions containing Cyt2Bc were purified from the crystal-negative strain SPL407 of B. thuringiensis. Cyt2Bc reacted weakly with antibodies directed against Cyt2Ba and was not recognized by an antiserum directed against the reference cytolysin Cyt1Aa. Cyt2Bc was hemolytic only upon activation with trypsin and had only one-third to one-fifth of the activity of Cyt2Ba, depending on the activation time. Cyt2Bc was also mosquitocidal against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus, including strains resistant to the Bacillus sphaericus binary toxin. Its toxicity was half of that of Cyt2Ba on all mosquito species except resistant C. quinquefasciatus.

Microhardness of enamel restored with fluoride and non-fluoride releasing dental materials

Demineralization caused by frequent ion loss can be detected by a decrease in enamel microhardness. The purpose of this study was to determine the microhardness of the enamel adjacent to restorations with fluoride and non-fluoride dental materials after demineralization and remineralization treatments using crowns of 6 recently extracted unerupted third molars which were sectioned into 4 parts. Five penetrations were made in the enamel of the control group and in the enamel adjacent to restorations made with Vitremer, Heliomolar or Z100, to obtain the Knoop microhardness. There was no significant statistical difference between the microhardness of the enamel of the control group and the enamel adjacent to the restorations made with Vitremer and Heliomolar (p < 0.01), nor between the enamel adjacent to the Heliomolar and Z100 restorations. However, there was a statistically significant difference when the Z100 group was compared to the control group and to the Vitremer group. The results point out that some phenomena occurred which interferred with the ionic loss and, consequently, the microhardness of the enamel of the Vitremer and Heliomolar groups, because it was not possible to observe any difference between the microhardness of the enamel of the control group and the groups restored with Vitremer and Heliomolar.

The role of the kidney in the clearance of calcitonin gene related peptide (CGRP)

Calcitonin gene-related peptide (CGRP) is a 37 amino-acid peptide, undetectable in the plasma in health but elevated in certain disease states such as medullary thyroid cancer, and potentially causes symptoms. The kidney is a major site of and influence on the clearance of exogenously infused CGRP. As CGRP might cause symptoms in renal dysfunction, this study was performed to determine the clearance of CGRP in humans and animals with altered renal function. In chronic renal failure patients, CGRP was not detected in plasma either before or after haemodialysis. In sheep, before and after bilateral nephrectomy, there was an approximate halving of plasma clearance and doubling of the circulating half-life of infused CGRP. This reduction in clearance was greater than that which could be accounted for by the reduction in degradation by renal substance alone. This renal influence on extra-renal CGRP metabolism was not due to the renal production of a circulating peptidase as evidenced by the absence of such peptidase in the plasma of normal and anephric sheep. Further, severity of uraemia had no influence on the extra-renal metabolism. The mechanism by which the kidney influences the extra-renal metabolism of CGRP remains obscure.

The intrarenal site of calcitonin gene-related peptide degradation in the isolated perfused rat kidney

1. Calcitonin gene-related peptide (CGRP) is a potent vaso-active 37 amino acid peptide, typically elevated in plasma from patients with medullary thyroid cancer (MTC), but undetectable in the plasma of normal subjects. 2. The kidney is a major site for the clearance of exogenously infused CGRP but the intrarenal site of this clearance is unknown. Extra-organ clearance is also significant for CGRP, and whereas the site and mechanism of this degradation remain uncertain, the vasculature has been postulated as the most likely site. 3. The isolated perfused rat kidney (IPRK) was studied to (i) localize the intrarenal site of CGRP clearance and (ii) determine the contribution of the renal vasculature to the clearance of CGRP. The half-life of CGRP in the filtering IPRK was 63.9 +/- 4.5 min, whereas blocking of filtration by elevation of the perfusate osmolarity abolished the degradation. This suggests that (i) renal CGRP degradation occurs after glomerular filtration with intratubular metabolism and (ii) that there is no active CGRP degradation in the (glomerular) capillary endothelium. 4. These results do not support the theory that renal vascular endothelium plays a major active role in CGRP degradation.

A (more) simple technique for locating the umbilicus in abdominoplasty

A method for simply and accurately locating the umbilicus in abdominoplasty is described. The method uses a shaped wire and ink.

Wound closure and suturing patterns: a vector analysis of suture tension

When the vectors of force required to close the ideal surgical wound are analysed, it is apparent that suture tension varies with the pattern of suture. For a given closing force, perpendicular interrupted sutures have the least tension. Symmetrical continuous sutures require greater suture tension, and this increases the more the suture is aligned with the direction of the wound. Asymmetrical (perpendicular/diagonal) continuous suturing requires more tension than interrupted sutures but this never exceeds 200%. Symmetrical suturing has slightly less tension than asymmetrical suturing when the spacing is about equal to the width of the suture. However, as the spacing ratio increases to greater than 2, the tension in the symmetrical suture rises very sharply. At a length:width ratio of 4, the symmetrical suture tension is about 70% greater than the same asymmetrical suturing.

Orbital blowout fracture from hydrostatic pressure

This case report describes an orbital blowout fracture due to hydrostatic pressure from a high-diving accident. Also described are the velocities encountered in this case.

Production of calcitonin gene related peptide, calcitonin and PTH-related protein by a prostatic adenocarcinoma

PTH and calcitonin are the two major hormones controlling calcium metabolism. Recently two new substances related to these hormones have been isolated: calcitonin gene related peptide (CGRP) and PTH-related protein (PTHrP). CGRP is a potent vasodilator and stimulant of intestinal secretion while PTHrP is probably the agent responsible for humoral hypercalcaemia of malignancy. We report here a patient with a prostatic tumour presenting with vasodilation, diarrhoea and hypercalcaemia. Our investigations revealed that the primary prostatic and liver secondary tumour contained CGRP, calcitonin and PTHrP. Most of the immunoreactive CGRP in the tumour and plasma co-eluted with the biologically active form of CGRP. The circulating levels of CGRP correlated with the presence of the diarrhoea. PTHrP concentration in the tumours was one of the highest reported for any tumour although previous studies may have utilized less than optimal extraction procedures. The somatostatin analogue, octreotide (SMS 201-995), did not reduce the plasma CGRP or the diarrhoea, a finding similar to that seen in patients with medullary thyroid carcinoma and high plasma CGRP. The hypercalcaemia was also unaffected by octreotide administration. This is the first report of a prostatic tumour associated with over-production of calcitonin, PTHrP and CGRP. The major life-threatening effects of this unusual case of prostatic carcinoma were diarrhoea and hypercalcaemia. Both these effects could be tentatively ascribed to newly discovered substances, CGRP and PTHrP. With the greater availability of assays to measure CGRP and PTHrP in plasma, a detailed examination of the incidence of over-production of these substances in various cancers will be possible.

The inactivation of Bacillus thuringiensis subsp. israelensis toxin by mosquito larvae proteases liberated into the medium

Crystal serine-proteases of B. thuringiensis subsp. israelensis were able to process the 28,000-dalton protein during crystal solubilization. On the other hand, solubilized crystal proteins were degraded during the larvicidal bioassay by the action of serine-proteases liberated by mosquito larvae into the medium, with loss of toxicity. However, proteins in intact crystals were protected from the action of these proteases. This resistance to degradation of crystals partly explains the observation that they are more toxic than solubilized crystal proteins.

Failure to induce mutations in Chinese hamster V79 cells and WB rat liver cells by the polybrominated biphenyls, Firemaster BP-6, 2,2',4,4',5,5'-hexabromobiphenyl, 3,3',4,4',5,5'-hexabromobiphenyl, and 3,3',4,4'-tetrabromobiphenyl

Firemaster BP-6 (FM), a mixture of polybrominated biphenyls (PBB), and the congeners 2,2',4,4',5,5'-hexabromobiphenyl (2,4,5-HBB), 3,3',4,4',5,5'-hexabromobiphenyl (3,4,5-HBB), and 3,3',4,4'-tetrabromobiphenyl (3,4-TBB) were tested for their ability to induce mutations in mammalian cells in culture. A rat liver microsome-mediated (S 15) Chinese hamster V79 cell mutation assay was used to test the mutagenicity of PBB and 3,4-TBB. V79 cells and WB rat liver cells were used to detect the mutagenicity of 2,4,5-HBB and 3,4,5-HBB. No mutagenic effects were detected at the dose levels tested. The possibility that these compounds promote liver neoplasms via a nongenotoxic mechanism is discussed.

Inhibition of intercellular communication in cultures of Chinese hamster V79 cells by 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid

Using the Chinese hamster V79 in vitro cell system designed to measure intercellular communication, 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and several mixtures of these compounds were tested for their ability to inhibit this biological process. The ability of these chemicals to inhibit colony-forming ability of these cells was tested prior to the studies to measure intercellular communication. 2,4-D was less cytotoxic than 2,4,5-T. Both 2,4,5-T and 2,4-D were able to inhibit intercellular communication at their respective noncytotoxic dose ranges. Various mixtures of both chemicals were also able to inhibit intercellular communication, showing some kind of additivity. No-effect levels were also noted in the intercellular communication assay. These results were interpreted as being consistent with the hypothesis that these compounds might be teratogenic by their ability to inhibit intercellular communication during development.