Potential use of waste from tree pruning and recovered plastic to obtain a building material: Case study of Merida, Mexico.

This work presents a study on the use of wood and plastic wastes generated in abundance in Merida, Mexico, to help to reduce them in order to mitigate environmental deterioration. The use of these wastes is proposed to obtain a low-cost building material. So, the escalation process (i.e., extrusion) at the pilot level to obtain a prototype of a wood-plastic composite (WPC) corrugated sheet to evaluate the technical feasibility to make a low-cost product is reported. A corrugated sheet with recycled high-density polyethylene (R-HDPE) was produced. The R-HDPE was collected from Merida's Separation Plant. The wood came from the trimmings of different varieties of trees and shrubs that are periodically pruned. WPC sheets with virgin HDPE were prepared to assess its effect on the materials' mechanical performance. The wood/HDPE weight ratio was 40/60. The performance of the WPC sheets was compared with that of commercial products with similar characteristics, namely acrylic and polyester sheets reinforced with fibreglass, and black asphalt-saturated cardboard sheets. Thus, the effect of natural weathering on the maximum tensile tearing force and on the maximum flexural load of the different types of sheets was evaluated. Although the mechanical performance of the WPC sheets was lower than that of the acrylic and polyacrylic sheets, their performance was much better than that of the cheap black asphalt-saturated cardboard sheets. So, they are a good option to be used as low-cost temporary roofing.

Active immunization of cattle with a bothropic toxoid does not abrogate envenomation by Bothrops asper venom, but increases the likelihood of survival.

This study assessed the protective effect of active immunization of cattle to prevent the envenomation induced by B. asper venom. Two groups of oxen were immunized with a bothropic toxoid and challenged by an intramuscular injection of either 10 or 50 mg B. asper venom, to induce moderate or severe envenomations, respectively. Non-immunized oxen were used as controls. It was found that immunized oxen developed local edema similar to those observed in non-immunized animals. However, systemic effects were totally prevented in immunized oxen challenged with 10 mg venom, and therefore antivenom treatment was not required. When immunized oxen were challenged with 50 mg venom, coagulopathy was manifested 3-16 h later than in non-immunized oxen, demonstrating a delay in the onset of systemic envenomation. In these animals, active immunization did not eliminate the need for antivenom treatment, but increased the time lapse in which antivenom administration is still effective. All experimentally envenomed oxen completely recovered after a week following venom injection. Our results suggest that immunization of cattle with a bothropic toxoid prevents the development of systemic effects in moderate envenomations by B. asper, but does not abrogate these effects in severe envenomation.

Organization and Characterization of the Promoter Elements of the rRNA Operons in the Slow-Growing Pathogen Mycobacterium kumamotonense.

The slow-growing, nontuberculous mycobacterium Mycobacterium kumamotonense possesses two rRNA operons, rrnA and rrnB, located downstream from the murA and tyrS genes, respectively. Here, we report the sequence and organization of the promoter regions of these two rrn operons. In the rrnA operon, transcription can be initiated from the two promoters, named P1 rrnA and PCL1, while in rrnB, transcription can only start from one, called P1 rrnB. Both rrn operons show a similar organization to the one described in Mycobacterium celatum and Mycobacterium smegmatis. Furthermore, by qRT-PCR analyses of the products generated from each promoter, we report that stress conditions such as starvation, hypoxia, and cellular infection affect the contribution of each operon to the synthesis of pre-rRNA. It was found that the products from the PCL1 promoter of rrnA play a pivotal role in rRNA synthesis during all stress conditions. Interestingly, the main participation of the products of transcription from the P1 promoter of rrnB was found during hypoxic conditions at the NRP1 phase. These results provide novel insights into pre-rRNA synthesis in mycobacteria, as well as the potential ability of M. kumamotonense to produce latent infections.

Teamwork to Survive in Hostile Soils: Use of Plant Growth-Promoting Bacteria to Ameliorate Soil Salinity Stress in Crops.

Plants and their microbiomes, including plant growth-promoting bacteria (PGPB), can work as a team to reduce the adverse effects of different types of stress, including drought, heat, cold, and heavy metals stresses, as well as salinity in soils. These abiotic stresses are reviewed here, with an emphasis on salinity and its negative consequences on crops, due to their wide presence in cultivable soils around the world. Likewise, the factors that stimulate the salinity of soils and their impact on microbial diversity and plant physiology were also analyzed. In addition, the saline soils that exist in Mexico were analyzed as a case study. We also made some proposals for a more extensive use of bacterial bioinoculants in agriculture, particularly in developing countries. Finally, PGPB are highly relevant and extremely helpful in counteracting the toxic effects of soil salinity and improving crop growth and production; therefore, their use should be intensively promoted.

A novel dual nerve transfer for restoration of shoulder function and sensory recovery of the hand, in patients with C567 traumatic root avulsion of the brachial plexus.

OBJECTIVE: The objective of our study is to determine the anatomical viability in cadavers of a novel doble nerve transfer technique for simultaneous reanimation of shoulder abduction and sensory recovery of the hand, in patients with brachial plexus injuries sustaining a C5-C6-C7 roots avulsion. These new transfers should be complemented in the clinical setting with other classic nerve transfers, i.e.: (1) a spinal accessory to suprascapular for shoulder abduction and stability, (2) ulnar nerve fascicles to the biceps branches of the musculocutaneous for elbow flexion, and (3) intercostal to triceps branches for elbow extension. METHODS: The proposed surgical technique includes (1) transferring motor fascicles of the median nerve (MNF), as donors to the axillary nerve (AN), and (2) the whole medial antebrachial cutaneous nerve (MACN) to the lateral contribution (sensory) of the median nerve (LCMN), both without the use of interposed nerve grafts. These techniques were performed in eight cadaveric upper extremities. Analyzed variables were: donor and receptor nerves diameter, length and distance of donor and receptors nerves, and axonal count. RESULTS: The mean distance between the MNF and its point of coaptation to the AN was 19 mm. The average length of each one of the MNF, after distal dissection, was 46.5 mm. The average diameter of each fascicle of the median nerve at its coaptation point with the axillary nerve was 0.8 mm, while the average diameter of the latter was 3.9 mm. The average distance between the MACN and its point of coaptation to the LCMN, was 16.5 mm. The average diameter of the MACN and the LCMN at their point of coaptation, were 2.7 mm and 3.5 mm, respectively. CONCLUSION: These nerve transfers are anatomically viable and could be a complement for other currently used techniques that can be employed in severely injured C567 brachial plexus patients.

Intraspecific variability of the Central American rattlesnake (Crotalus simus) venom and its usefulness to obtain a representative standard venom.

Snake venoms are mixtures of proteins whose physicochemical features confer them toxicity and immunogenicity. Animals (e.g., horses or sheep) immunized with snake venoms produce antibodies towards the venom proteins. Since these antibodies can neutralize the venom toxicity, they have been used to formulate snake antivenoms. The efficacy of the antivenoms is widely accepted, and standard venoms are expected to be representative of the snake's population that inhabit in the region where the antivenom is intended to be used. The representativeness of a single venom collected from a Crotalus simus snake, and its usefulness as standard venom to produce an antivenom is evaluated. The use of an "average venom" might be as representative of the population intended to be used, as the standard venom composed by many venom samples. Variations in the relative abundance concentration of crotoxin in the C. simus leads to different clinical manifestations, as well as differences in the neutralization efficacy of the antivenoms. A monovalent anti-Cs antivenom was produced from a single venom C. simus specimen, and its efficacy in neutralizing the lethal activity of 30 C. simus snakes was tested. Despite the variations in the relative abundance content of crotoxin found in the proteomes, the monovalent anti-Cs antivenom was successful in neutralize the toxicity caused by the variations on the venom composition of three different snake population used. Interestingly, it seems that the sex is not a key factor in the lethality of the venoms tested. The concept of representative venom mixtures for immunization should be revised for the case of C. simus on the populations found in Costa Rica, since it might use as less as one representative individual whose venom covers the mainly toxic enzymes.

Expanding the neutralization scope of the Central American antivenom (PoliVal-ICP) to include the venom of Crotalus durissus pifanorum.

The proteomic, enzymatic, toxicological, and immunogenic profiles of the venom of C. d. pifanorum were studied. It was found that venom of C. d. pifanorum is composed of 63% phospholipases A2 (PLA2s), 13% serine proteinases (SVSPs), 8% bradykinin-potentiating peptides (BPPs), 4% L-amino acid oxidases (LAAOs), 3% metalloproteinases (SVMPs), and other minor components. This composition allows the venom to exert lethal, PLA2, myotoxic, coagulant and defibrinogenating activities, but no azocaseinolytic or hemorrhagic activities. The addition of C. d. pifanorum venom to the group of venoms used as immunogens to produce the Central American antivenom PoliVal-ICP (i.e., venoms of Bothrops asper, Crotalus simus and Lachesis stenophrys) resulted in 1) the expansion of the neutralization scope of the antivenom to cover the venom of C. d. pifanorum and other antigenically related venom (i.e., C. s. scutulatus venom), 2) improvement of the neutralizing potency towards the venom of C. simus, and 3) no significant reduction of the neutralization of venoms of B. asper and L. stenophrys. It was concluded that supplementation of the immunogens used to produce PoliVal-ICP with the venom of C. d. pifanorum is a viable alternative to expand the neutralization scope of the antivenom. BIOLOGICAL SIGNIFICANCE: The venom of Crotalus durissus pifanorum from Venezuela has a proteomic profile like those of other subspecies of the South American rattlesnake C. durissus, with predominance of phospholipases A2 (especially crotoxin) and serine proteinases. This explains a toxicological profile characterized by neurotoxicity, myotoxicity, and coagulopathies, but being devoid of hemorrhagic activity. The antivenom used in Central America (PoliVal-ICP) includes the venom of C. simus, which has a different composition, in the immunizing strategy. Accordingly, this antivenom does not neutralize C. d. pifanorum venom. The addition of C. d. pifanorum venom to the immunizing mixture of PoliVal-ICP expands the neutralizing scope of this antivenom, to cover additional rattlesnake venoms, while not affecting the response to C. simus, Bothrops asper and Lachesis stenophrys venoms. This represents an improvement of the current PoliVal-ICP.

Development and characterization of two equine formulations towards SARS-CoV-2 proteins for the potential treatment of COVID-19.

In the current global emergency due to SARS-CoV-2 outbreak, passive immunotherapy emerges as a promising treatment for COVID-19. Among animal-derived products, equine formulations are still the cornerstone therapy for treating envenomations due to animal bites and stings. Therefore, drawing upon decades of experience in manufacturing snake antivenom, we developed and preclinically evaluated two anti-SARS-CoV-2 polyclonal equine formulations as potential alternative therapy for COVID-19. We immunized two groups of horses with either S1 (anti-S1) or a mixture of S1, N, and SEM mosaic (anti-Mix) viral recombinant proteins. Horses reached a maximum anti-viral antibody level at 7 weeks following priming, and showed no major adverse acute or chronic clinical alterations. Two whole-IgG formulations were prepared via hyperimmune plasma precipitation with caprylic acid and then formulated for parenteral use. Both preparations had similar physicochemical and microbiological quality and showed ELISA immunoreactivity towards S1 protein and the receptor binding domain (RBD). The anti-Mix formulation also presented immunoreactivity against N protein. Due to high anti-S1 and anti-RBD antibody content, final products exhibited high in vitro neutralizing capacity of SARS-CoV-2 infection, 80 times higher than a pool of human convalescent plasma. Pre-clinical quality profiles were similar among both products, but clinical efficacy and safety must be tested in clinical trials. The technological strategy we describe here can be adapted by other producers, particularly in low- and middle-income countries.

Impact of regional variation in Bothrops asper snake venom on the design of antivenoms: integrating antivenomics and neutralization approaches.

Intraspecific snake venom variations have implications in the preparation of venom pools for the generation of antivenoms. The impact of such variation in the cross-reactivity of antivenoms against Bothrops asper venom was assessed by comparing two commercial and four experimental antivenoms. All antivenoms showed similar immunorecognition pattern toward the venoms from adult and neonate specimens. They completely immunodepleted most P-III snake venom metalloproteinases (SVMPs), l-amino acid oxidases, serine proteinases, DC fragments, cysteine-rich secretory proteins (CRISPs), and C-type lectin-like proteins, and partially immunodepleted medium-sized disintegrins, phospholipases A(2) (PLA(2)s), some serine proteinases, and P-I SVMPs. Although all antivenoms abrogated the lethal, hemorrhagic, coagulant, proteinase, and PLA(2) venoms activities, monospecific experimental antivenoms were more effective than the polyspecific experimental antivenom. In addition, the commercial antivenoms, produced in horses subjected to repeated immunization cycles, showed higher neutralization than experimental polyspecific antivenom, produced by a single round of immunization. Overall, a conspicuous pattern of cross-neutralization was evident for all effects by all antivenoms, and monospecific antivenoms raised against venom from the Caribbean population were effective against venom from the Pacific population, indicating that geographic variations in venom proteomes of B. asper from Costa Rica do not result in overt variations in immunological cross-reactivity between antivenoms.

Intravenous administration of equine-derived whole IgG antivenom does not induce early adverse reactions in non-envenomed horses and cows.

Administration of antivenoms to treat snakebite envenomings has the potential risk of inducing early adverse reactions. The mechanisms involved in these reactions are unclear. In this study, polyspecific antivenom consisting of whole IgG purified from equine plasma by caprylic acid precipitation was administered intravenously to non-envenomed horses (n = 47) and cows (n = 20) at a dose of 0.4 mL/kg. It has been reported that, in humans, this formulation (administered at a dose of 0.4 mL/kg) induces mild noticeable early adverse reactions, such as fever, vomiting, diarrhea, urticaria, generalized rash, tachypnea or tachycardia, in about 15-20% of the patients. Unexpectedly, none of the animals receiving antivenom in our study showed any evidence of early adverse reaction. Moreover, no late adverse reactions, i.e. serum sickness, were observed during 40 days after antivenom administration. Unlike studies performed in envenomed humans, our present results were obtained in a group of non-envenomed individuals. It is concluded that, in addition to the physicochemical characteristics of the formulation, other unknown factors must determine the occurrence of adverse reactions in snakebite envenomed humans treated with equine-derived antivenoms.

A preliminary study on the preparation of wood-plastic composites from urban wastes generated in Merida, Mexico with potential applications as building materials.

A preliminary study on the use of wood and plastic wastes generated in Merida, Mexico to assess their potential for the development of building materials is reported. Composites based on recycled, high-density polyethylene (R-HDPE) loaded with wood particles were prepared. The R-HDPE was collected from Merida's Separation Plant, where it was sorted from other residues, either organic or inorganic. Composites based on virgin, high-density polyethylene (V-HDPE) were also prepared to assess the effect of the R-HDPE on the composite's mechanical properties. The wood came from the trims of different varieties of the city's trees that are periodically pruned as part of the cleaning and urbanising programmes implemented by the City Council. A batch of this material was selected at random to incorporate into both the R-HDPE and V-HDPE. Different wood particle sizes were experimented with to obtain extruded composites with contents of 50% and 60% by weight of wood that were characterized under tension and impact. Flat wood-plastic extrudates with reasonable good appearance were also produced at the laboratory level as a first step to find an adequate route to scale-up the process to a pilot level to evaluate the feasibility of producing alternative building materials.

Contributions of the snake venoms of Bothrops asper, Crotalus simus and Lachesis stenophrys to the paraspecificity of the Central American polyspecific antivenom (PoliVal-ICP).

PoliVal-ICP antivenom is produced from plasma of horses immunized toward the venoms of Bothrops asper, Crotalus simus and Lachesis stenophrys. The antibody response induced by these venoms confers PoliVal-ICP the capacity to neutralize the venoms of the most important Central American viperids, including not only homologous venoms (i.e., venoms used as immunogen), but many heterologous venoms (i.e., venoms not used as immunogen). In this work, the individual contributions of homologous venoms to the paraspecificity of PoliVal-ICP were inferred from the capacity of experimental monospecific antivenoms toward venoms of B. asper (anti-Ba), C. simus (anti-Cs) and L. stenophrys (anti-Ls), and an experimental polyspecific antivenom (anti-Ba/Cs/Ls) to neutralize the lethality induced by different venoms in mice. It was found that all antivenoms neutralized their corresponding homologous venoms. Moreover, the anti-Ba antivenom cross-neutralized the venoms of Agkistrodon howardgloydi, Atropoides picadoi, Bothriechis lateralis, Bothriechis supraciliaris and Porthidium ophryomegas; the anti-Cs antivenom cross-neutralized the venoms of B. lateralis, B. supraciliaris, Cerrophidion sasai and Porthidium nasutum; and the anti-Ls antivenom cross-neutralized the venoms of B. lateralis, B. supraciliaris, C. sasai and Lachesis melanocephala. All venoms neutralized by any monospecific antivenom were also neutralized by the anti-Ba/Cs/Ls antivenom. Venoms of Atropoides mexicanus, Bothriechis nigroviridis and Bothriechis schlegelii were not neutralized by any experimental antivenom, thus explaining the limitations of PoliVal-ICP to neutralize these venoms. Consequently, an enlargement of the neutralization scope of PoliVal-ICP could be achieved by including these venoms in the group of those used as immunogens.

Current technology for the industrial manufacture of snake antivenoms.

Snake antivenoms are formulations of animal immunoglobulins used in the treatment of snakebite envenomation. The general scheme for producing snake antivenoms has undergone few changes since its development more than a century ago; however, technological innovations have been introduced in the manufacturing process. These medicines must comply with identity, purity, safety and efficacy profiles, as requested by the current Good Manufacturing Practices (GMPs) applied to modern biopharmaceutical drugs. Industrial production of snake antivenoms comprises several stages, such as: 1) production of reference venom pools, 2) production of hyperimmune plasma, 3) purification of the antivenom immunoglobulins, 4) formulation of the antivenom, 5) stabilization of the formulation, and 6) quality control of in-process and final products. In this work, a general review of the existing technology used for the industrial manufacture of snake antivenoms is presented.

Evaluación antifúngica del ozono contra Candida albicans: estudio in vitro / Antifungal evaluation of ozone against Candida albicans: in vitro study

Introducción: la Candida albicans (C. albicans) es un patógeno fúngico que puede causar infecciones superficiales o potencialmente mortales. Los biofilms de C. albicans muestran rasgos fenotípicos únicos, el más destacado es su notable resistencia a una amplia variedad de agentes antimicóticos. Una de las alternativas para inhibir el crecimiento de este microorganismo es el ozono debido a sus propiedades bactericidas, fungicidas y virucidas; sin embargo, escasa información ha sido reportada en C. albicans. Objetivo: el objetivo de este estudio fue evaluar el efecto fungicida del ozono en C. albicans. Material y métodos: la metodología consistió en agregar ozono a tubos de ensayo con medios de caldo nutritivo en diversas concentraciones y tiempos de ozonización. El efecto fungicida fue determinado con la determinación del número de colonias de C. albicans en agar nutritivo a través de procedimiento microbiológicos estandarizados por triplicado. Resultados: todas las muestras con ozono mostraron adecuados niveles de inhibición de crecimiento del microorganismo. Además, el efecto fungicida del ozono se encontró para ser significativamente dependiente del tiempo de ozonización y de la concentración. Conclusión: el uso de terapia con ozono podría tener potencial en el control de infecciones micóticas causadas por la presencia de C. albicans (AU)

Introduction: Candida albicans (C. albicans) is a fungal pathogen that can cause superficial or life-threatening infections. Biofilms of C. albicans display unique phenotypic traits, the most prominent being their remarkable resistance to a wide variety of antifungal agents. One of the alternatives to inhibit the growth of this microorganism is ozone due to its bactericidal, fungicidal and virucidal properties; however, little information has been reported on C. albicans. Objective: the objective of this study was to evaluate the fungicidal effect of ozone on C. albicans. Material and methods: the methodology consisted in adding ozone to test tubes with nutrient broth media in various concentrations and ozonation times. The fungicidal effect was determined by determining the number of colonies of C. albicans in nutrient agar through standardized microbiological procedures in triplicate. Results: all the ozone samples showed adequate levels of growth inhibition of the microorganism. Furthermore, the fungicidal effect of ozone was found to be significantly dependent on ozonation time and concentration. Conclusion: the use of ozone therapy could have potential in the control of fungal infections caused by the presence of C. albicans (AU)

Expanding the neutralization scope of the EchiTAb-plus-ICP antivenom to include venoms of elapids from Southern Africa.

EchiTAb-plus-ICP is an antivenom prepared from plasma of horses hyperimmunized with the venoms of the carpet viper (Echis ocellatus), the puff adder (Bitis arietans) and the black-necked spitting cobra (Naja nigricollis). Therefore, the use of this antivenom has been limited to Western Africa. In order to expand the neutralization scope of EchiTAb-plus-ICP, we supplemented the immunogenic mixture with the venoms of B. arietans, the black mamba (Dendroaspis polylepis), the Mozambique spitting cobra (Naja mossambica), the snouted cobra (N. annulifera), and the rinkhals (Hemachatus haemachatus) from Swaziland. The ability of the expanded-scope antivenom, hereby named EchiTAb + ICP, to neutralize the venoms of B. arietans, D. polylepis, N. mossambica and H. haemachatus was similar to those of FAV Afrique and the SVA African antivenoms. In comparison to the SAIMR antivenom, the expanded-scope EchiTAb + ICP had lower ability to neutralize the venom of B. arietans, but similar ability to neutralize the venoms of D. polylepis, N. mossambica and H. haemachatus. Owing to its low protein concentration, the expanded-scope EchiTAb + ICP had lower ability to neutralize the venom of N. annulifera than FAV Afrique and the SAIMR antivenoms. However, when formulated at a protein concentration as high as FAV Afrique and SAIMR antivenoms, the expanded-scope EchiTAb + ICP showed similar capacity to neutralize this poorly immunogenic venom. Our results encourage the transition to the new EchiTAb + ICP antivenom, with an expanded neutralization scope that includes venoms of some of the most medically important elapids from Southern Africa. Clinical trials are required to determine the minimum effective-safe dose of the new EchiTAb + ICP for each type of envenomation.

Cross-reactivity and cross-immunomodulation between venoms of the snakes Bothrops asper, Crotalus simus and Lachesis stenophrys, and its effect in the production of polyspecific antivenom for Central America.

A mixture of the venoms of Bothrops asper, Crotalus simus and Lachesis stenophrys is used as immunogen to produce the polyspecific Central American antivenom (PoliVal-ICP). In this work, we studied the ability of each of these venoms to modulate the antibody response induced by the other two venoms included in the immunization mixture. For that, equine monospecific, bispecific and polyspecific antivenoms were prepared and compared regarding their ability to neutralize the phospholipase A2, coagulant and lethal activities of each venom, and their anti-venom antibodies concentration. Results indicate that there is low cross-reactivity and cross-neutralization between venoms of B. asper, C. simus and L. stenophrys, hence justifying the use of all of them as immunogens for the production of the Central American antivenom. It was also found that the venom of B. asper reduces the anti-crotalic response while the venom of C. simus does not affect the anti-bothropic response. On the other hand, the venoms of B. asper and C. simus increase the anti-lachesic response, and L. stenoprhys venom reduced both the anti-bothropic and anti-crotalic responses. On the basis of these results, the immunization strategy can be adjusted by preventing or taking advantage of cross-immunomodulation between venoms, in order to maximize the antibody response towards all venoms. Immune responses can be improved by injecting horses with several immunogen mixtures, composed by one or two of the three venoms, and administering them at different times during the immunization, eventually generating a high titer against the three venoms. Our results suggest that addressing the issue of immunomodulation by venoms might improve antivenom manufacture worldwide.

Development of a new polyspecific antivenom for snakebite envenoming in Sri Lanka: Analysis of its preclinical efficacy as compared to a currently available antivenom.

A new whole IgG, freeze-dried, polyspecific antivenom was prepared from the plasma of horses immunized with the venoms of the snakes Daboia russelii, Echis carinatus, Hypnale hypnale, and Naja naja from Sri Lanka. The preclinical neutralizing ability of this antivenom against several toxic and enzymatic activities of these four venoms was analyzed, and compared with that of a batch of VINS antivenom (India) being currently used in Sri Lanka. The activities tested were: lethality, hemorrhagic, in vitro coagulant, proteinase and phospholipase A2. Both antivenoms neutralized, to a different extent, these activities of the venom of D. russelii, E. carinatus, and N. naja. In general, the polyspecific Sri Lankan antivenom was more effective than the Indian antivenom in the neutralization of the venoms of D. russelii and E. carinatus, whereas the Indian antivenom showed a higher efficacy against the venom of N. naja. Regarding H. hypnale, the new Sri Lankan antivenom was effective in the neutralization of all activities tested, whereas the Indian antivenom neutralized lethality but not hemorrhagic, coagulant, proteinase and PLA2 activities, in agreement with the fact that this venom is not included in the immunization mixture for this antivenom. Results suggest that the new polyspecific Sri Lankan antivenom has a satisfactory preclinical neutralizing profile and compares favorably with the Indian antivenom. This is ready to be tested in a clinical trial to evaluate its efficacy and safety in human victims of snakebite envenomings by D. russelii, E. carinatus and H. hypnale in Sri Lanka.

Effect of geographical variation of Echis ocellatus, Naja nigricollis and Bitis arietans venoms on their neutralization by homologous and heterologous antivenoms.

Two antivenoms prepared by using Echis ocellatus, Bitis arietans and Naja nigricollis venoms from different locations in sub-Saharan Africa were compared for their neutralizing ability. Both antivenoms were similarly effective in the neutralization of the venoms of the three species from different locations. However in the case of E. ocellatus venom, antivenom prepared using venom from Nigerian specimens was more effective than antivenom prepared with venom from Cameroon specimens in the neutralization of coagulant activity.

Lachesis stenophrys venom reduces the equine antibody response towards Bothrops asper venom used as co-immunogen in the production of polyspecific snake antivenom.

The anti-bothropic activity of an antivenom prepared from the plasma of horses immunized with Bothrops asper venom (anti-B antivenom) was compared with a similar formulation produced from the plasma of horses immunized with a mixture of B. asper and Lachesis stenophrys venoms (anti-BL antivenom). Likewise, a comparison between the anti-lachesic activity of the anti-BL antivenom and a similar formulation prepared from horses immunized only with L. stenophrys venom (anti-L antivenom) was performed. The anti-BL antivenom had lower concentration of anti-bothropic antibodies than the anti-B antivenom. This difference was associated to a lower response towards all components of B. asper venom, but particularly towards some D49-phospholipases A2 (PLA2s) and PIII-metalloproteinases. Consequently, the anti-BL antivenom was less effective neutralizing lethal, coagulant, defibrinogenating, PLA2, and myotoxic activities of B. asper venom. On the other hand, anti-BL and anti-L antivenoms showed similar concentration of anti-lachesic antibodies, and similar capacity to recognize the HPLC fractions of L. stenophrys venom and to neutralize lethal, coagulant, proteolytic, hemorrhagic, PLA2 and myotoxic activities induced by this venom. It is concluded that, when used as co-immunogens, the venom of L. stenophrys reduces the antibody response towards B. asper venom, whereas the latter does not affect the anti-lachesic response.

Electrophoretic analysis of whole saliva and prevalence of dental caries. A study in Mexican dental students.

BACKGROUND: Variability in salivary proteins and their posttranslational modifications may play an important role in determining their protective features against dental caries. Knowledge of molecular content of saliva in different populations is important for a better understanding of protective properties of this biological fluid. Aims of this study were to analyze electrophoretic pattern and protein composition in resting human whole saliva (HWS) of a Mexican population and to correlate these data with decayed, missing, and filled teeth (DMFT) index in these subjects. METHODS: Resting human whole saliva samples were collected from 120 healthy Mexican dental students. Salivary flow rate, protein concentration, and electrophoretic profile analyzed qualitatively by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were correlated with DMFT index. Gels were successively triple-stained with Coomassie brilliant blue R250, periodic acid Schiff (PAS), silver stain, and salivary molecules were scored as absent (-), present (+/-), and high intensity and size (+). RESULTS: These showed no substantial differences in number of bands between males and females; however, a slight correlation between total protein concentration and sex was found (p