Toxicity of five Cry proteins against the insect pest Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchinae).

The beetle Acanthoscelides obtectus (Say) causes severe post-harvest losses in the common bean (Phaseolus vulgaris). Under laboratory conditions, the susceptibility of A. obtectus to five coleopteran-specific Cry toxic proteins from Bacillus thuringiensis (Cry1Ba, Cry1Ia, Cry3Aa, Cry7Ab, and Cry23/37) was evaluated. After 30 days exposure, Cry proteins demonstrated high activity against A. obtectus adults (100% mortality). Proteins showed statistical differences in toxicity parameters compared to the control treatment, but the parameters were similar among them, and indicated that the final toxic effects can be observed after the 24th day. The toxic effects on A. obtectus larvae were evaluated indirectly by allowing adults to oviposit on treated beans and recording the emergence of F1 adults. All treatments resulted in a lower rate of successful emergence compared to the control treatment, ranging from 60% (Cry23/37) to 10% (Cry1Ia) reduction in eclosion. Finally, to evaluate the ability of Cry proteins to protect the beans against A. obtectus; the number of beans infested, the number of holes in each bean and bean weight loss were determined 45 days after the treatment. The parameters showed significant bean protection by all Cry proteins analyzed compared to control treatment. Cry23/37 showed the best results, however, results for the other proteins were similar. The proteins belong to different Cry protein families, which suggest that they could be used in combination to increase plant protection without compromising resistance management. Moreover, adult emergence and bean protection results indicate differences among the proteins, which may suggest different modes of action. Our results indicate that the studied Cry proteins can be applied for the control of A. obtectus larvae and adults.

Effect of Trichoderma velutinum and Rhizoctonia solani on the Metabolome of Bean Plants (Phaseolus vulgaris L.).

The common bean (Phaseolus vulgaris L.) is one of the most important food legume crops worldwide that is affected by phytopathogenic fungi such as Rhizoctonia solani. Biological control represents an effective alternative method for the use of conventional synthetic chemical pesticides for crop protection. Trichoderma spp. have been successfully used in agriculture both to control fungal diseases and to promote plant growth. The response of the plant to the invasion of fungi activates defensive resistance responses by inducing the expression of genes and producing secondary metabolites. The purpose of this work was to analyze the changes in the bean metabolome that occur during its interaction with pathogenic (R. solani) and antagonistic (T. velutinum) fungi. In this work, 216 compounds were characterized by liquid chromatography mass spectrometry (LC-MS) analysis but only 36 were noted as significantly different in the interaction in comparison to control plants and they were tentatively characterized. These compounds were classified as: two amino acids, three peptides, one carbohydrate, one glycoside, one fatty acid, two lipids, 17 flavonoids, four phenols and four terpenes. This work is the first attempt to determine how the presence of T. velutinum and/or R. solani affect the defense response of bean plants using untargeted metabolomics analysis.

Inhibitory activity of Beauveria bassiana and Trichoderma spp. on the insect pests Xylotrechus arvicola (Coleoptera: Cerambycidae) and Acanthoscelides obtectus (Coleoptera: Chrisomelidae: Bruchinae).

Xylotrechus arvicola is an important pest in vineyards (Vitis vinifera) in the main Iberian wine-producing regions, and Acanthoscelides obtectus causes severe post-harvest losses in the common bean (Phaseolus vulgaris). Under laboratory conditions with a spray tower, the susceptibility of the immature stages of X. arvicola and A. obtectus against the entomopathogenic fungi Beauveria bassiana and four strains of Trichoderma spp. was evaluated. Both insect pests T. harzianum and B. bassiana showed a good inhibitory activity, accumulating an inhibition on the eggs of values above 85 and 82%, respectively. T. atroviride and T. citrinoviride had a lower inhibitory activity, with inhibition values of 74.1 and 73.3% respectively. These fungi can be considered a highly effective tool for the control during the immature stages of these species.

Trichoderma carraovejensis: a new species from vineyard ecosystem with biocontrol abilities against grapevine trunk disease pathogens and ecological adaptation.

Trichoderma strains used in vineyards for the control of grapevine trunk diseases (GTDs) present a promising alternative to chemical products. Therefore, the isolation and characterization of new indigenous Trichoderma strains for these purposes is a valuable strategy to favor the adaptation of these strains to the environment, thus improving their efficacy in the field. In this research, a new Trichoderma species, Trichoderma carraovejensis, isolated from vineyards in Ribera de Duero (Spain) area, has been identified and phylogenetically analyzed using 20 housekeeping genes isolated from the genome of 24 Trichoderma species. A morphological description and comparison of the new species has also been carried out. In order to corroborate the potential of T. carraovejensis as a biological control agent (BCA), confrontation tests against pathogenic fungi, causing various GTDs, have been performed in the laboratory. The compatibility of T. carraovejensis with different pesticides and biostimulants has also been assessed. This new Trichoderma species demonstrates the ability to control pathogens such as Diplodia seriata, as well as high compatibility with powdered sulfur-based pesticides. In conclusion, the autochthonous species T. carraovejensis can be an effective alternative to complement the currently used strategies for the control of wood diseases in its region of origin.

Vineyard Management and Physicochemical Parameters of Soil Affect Native Trichoderma Populations, Sources of Biocontrol Agents against Phaeoacremonium minimum.

Native strains of Trichoderma in vineyard soil represent an opportunity for reducing the incidence of grapevine trunk diseases (GTDs) in vineyards. Moreover, its relationship with the environment (physicochemical soil characteristics and farming management practices) remains unclear. In the current study, a survey was carried out on farming management used by viticulturists, and soil samples were studied to analyze their physicochemical properties and to isolate Trichoderma strains. Later, statistical analyses were performed to identify possible correlations between Trichoderma populations, soil management and soil characteristics. In addition, in vitro tests, including antibiosis and mycoparasitism, were performed to select those Trichoderma strains able to antagonize Phaeoacremonium minimum. In this study a positive correlation was found between the iron content and pH in the soil, and a lower pH increases Trichoderma populations in soils. Vineyard management also affects Trichoderma populations in the soil, negatively in the case of fertilization and tillage and positively in the case of herbicide spraying. Two Trichoderma native strains were selected as potential biocontrol agents (Trichoderma gamsii T065 and Trichoderma harzianum T087) using antibiosis and mycoparasitism as mechanisms of action. These results led to the conclusion that native Trichoderma strains hold great potential as biological control agents and as producers of secondary metabolites.

Xylotrechus arvicola (Coleoptera: Cerambycidae) capture in vineyards in relation to climatic factors.

BACKGROUND: Captures and seasonal abundance of Xylotrechus arvicola (Coleoptera: Cerambycidae) in relation to climatic factors were studied in vineyards between the years 2013 and 2020. Insects captures from vine wood in two Vitis vinifera varieties were evaluated every year by counting the number of insects captured with CROSSTRAP®. The captured insects were grouped (by sex and total) into ranges of 10 days and compared to climatic data (daily average, temperature and rainfall) for each cultivar and year. RESULTS: The capture periods spanned from 1 June and 31 July, with the period from 1 to 30 June having the greatest number of insect captures, as long as weather conditions were favourable, i.e. temperature above 20.00 °C and accumulated rainfall in 10 days lower than 0.40 mm, verified through the analysis of parameter estimates, in which, only the temperature parameter was significantly. CONCLUSIONS: The study provided useful information for the integrated pest management of X. arvicola through mass trapping in vineyards when temperature exceeds 20.00 °C and the accumulated rainfall is less than 0.40 mm in 10 days to obtain peak captures. This is the first quantitative study of X. arvicola control associated with temperature and rainfall in Vitis vinifera. © 2022 Society of Chemical Industry.

Effects of trichothecene production by Trichoderma arundinaceum isolates from bean-field soils on the defense response, growth and development of bean plants (Phaseolus vulgaris).

The trichothecene toxin-producing fungus Trichoderma arundinaceum has potential as a biological control agent. However, most biocontrol studies have focused only on one strain, IBT 40837. In the current study, three Trichoderma isolates recovered from bean-field soils produced the trichothecene harzianum A (HA) and trichodermol, the latter being an intermediate in the HA biosynthesis. Based on phylogenetic analysis, the three isolates were assigned to the species T. arundinaceum. Their genome sequences had a high degree of similarity to the reference IBT 40837 strain, in terms of total genome size, number of predicted genes, and diversity of putative secondary metabolite biosynthetic gene clusters. HA production by these bean-field isolates conferred significant in vitro antifungal activity against Rhizoctonia solani and Sclerotinia sclerotiorum, which are some of the most important bean pathogens. Furthermore, the bean-field isolates stimulated germination of bean seeds and subsequent growth of above ground parts of the bean plant. Transcriptomic analysis of bean plants inoculated with these T. arundinaceum bean-field soil isolates indicated that HA production significantly affected expression of plant defense-related genes; this effect was particularly significant in the expression of chitinase-encoding genes. Together, these results indicate that Trichoderma species producing non-phytotoxic trichothecenes can induce defenses in plants without negatively affecting germination and development.

Effect of Farnesol in Trichoderma Physiology and in Fungal-Plant Interaction.

Farnesol is an isoprenoid intermediate in the mevalonate (MVA) pathway and is produced by the dephosphorylation of farnesyl diphosphate. Farnesol plays a central role in cell growth and differentiation, controls production of ubiquinone and ergosterol, and participates in the regulation of filamentation and biofilm formation. Despite these important functions, studies of farnesol in filamentous fungi are limited, and information on its effects on antifungal and/or biocontrol activity is scarce. In the present article, we identified the Trichoderma harzianum gene dpp1, encoding a diacylglycerol pyrophosphatase that catalyzes production of farnesol from farnesol diphosphate. We analyzed the function of dpp1 to address the importance of farnesol in Trichoderma physiology and ecology. Overexpression of dpp1 in T. harzianum caused an expected increase in farnesol production as well as a marked change in squalene and ergosterol levels, but overexpression did not affect antifungal activity. In interaction with plants, a dpp1-overexpressing transformant acted as a sensitizing agent in that it up-regulated expression of plant defense salicylate-related genes in the presence of a fungal plant pathogen. In addition, toxicity of farnesol on Trichoderma and plants was examined. Finally, a phylogenetic study of dpp1 was performed to understand its evolutionary history as a primary metabolite gene. This article represents a step forward in the acquisition of knowledge on the role of farnesol in fungal physiology and in fungus-environment interactions.

Spores of Trichoderma Strains over P. vulgaris Beans: Direct Effect on Insect Attacks and Indirect Effect on Agronomic Parameters.

Acanthoscelides obtectus is an insect pest that attacks wild and cultivated common beans (Phaseolus vulgaris L). Four Trichoderma strains, the T. arundinaceum IBT 40837 wild-type strain (=Ta37), a producer of trichothecene harzianum A (HA), two transformants of T. arundinaceum strain, Ta37-17.139 (=Δtri17) and Ta37-23.74 (=Δtri23), and the T. brevicompactum IBT 40841 wild-type strain (=Tb41), which produces the trichothecene trichodermin, were assessed to establish their direct effect on insect attacks and their indirect effect on the plants grown from the beans treated with those fungal strains and exposed to insect attacks. Treatments of bean seeds with different Trichoderma strains led to different survival rates in the insects, and the Tb41 strain caused the lowest survival rate of all. An 86.10% of the insect cadavers (in contact with Δtri23) showed growth of this strain. This was the treatment that attracted the greatest number of insects. The daily emergence was reduced in beans treated with the Ta37, Tb41, and Δtri17 strains. The undamaged beans treated with Ta37 and Δtri23 showed a high capacity of germination (80.00% and 75.00%, respectively), whereas the Δtri17 and Tb41 treatments increased the capacity of germination in the damaged beans (66.67%). The undamaged beans treated with Δtri23 had the greatest dry weights for the aerial part (4.22 g) and root system in the plants (0.62 g). More studies on the mechanisms of insect control, plant growth promotion, and trichodermol and trichodermin production by Δtri23 and Tb41, respectively, should be explored in order to commercialize these fungal species on a large scale.

Mating Disruption of the Olive Moth Prays oleae (Bernard) in Olive Groves Using Aerosol Dispensers.

The olive moth (OM), Prays oleae (Bern.) (Lepidoptera: Yponomeutidae), is a major olive grove pest worldwide; however, until now, very few studies have investigated the effectiveness of mating disruption (MD) techniques against this pest. Experiments were carried out for two successive years (2019 and 2020) in three different olive groves in Andalucía (Southern Spain) to evaluate mating disruption's efficacy in controlling the OM from the first to the third generation. The effectiveness of MD formulations against the three generations of OM was assessed by determining the percentage of infested olive fruits, the reduction of pheromone trap catches, and the number of affected inflorescences in both MD-treated and untreated control olive groves. The number of release points (one or two aerosol devices per ha) was also evaluated. In all years and trials, the mean number of males caught in traps placed in the MD-treated plots was significantly lower than untreated sites. Mating disruption registered a high suppression of male captures (>75%) in treated plots for two consecutive seasons. Concerning infested olive fruits, substantial reductions (about 80%) were observed in the MD plots of locations B and C, and a reduction of about 40% was detected in location A, compared to the control plot. Results showed that the installation of two aerosol devices/ha reduced fruit damage below 20% of infested olive fruits except for one site where a reduction of about 71% in the MD plot was recorded in 2019. Although few significant differences were associated with OM male catches and infested olive fruits between plots treated with one aerosol/ha and two aerosols/ha in most of the comparisons, significant differences in the number of olive inflorescences infested by P. oleae were found, suggesting a similar performance between the two tested aerosol densities. Results of two-year field trials in Andalucía demonstrated the potential of Mister P X841 aerosol devices as an effective tool for controlling the olive moth, P. oleae.

Volatile Organic Compound Chamber: A Novel Technology for Microbiological Volatile Interaction Assays.

The interest in the study of microbiological interactions mediated by volatile organic compounds (VOCs) has steadily increased in the last few years. Nevertheless, most assays still rely on the use of non-specific materials. We present a new tool, the volatile organic compound chamber (VOC chamber), specifically designed to perform these experiments. The novel devices were tested using four Trichoderma strains against Fusarium oxysporum and Rhizoctonia solani. We demonstrate that VOC chambers provide higher sensitivity and selectivity between treatments and higher homogeneity of results than the traditional method. VOC chambers are also able to test both vented and non-vented conditions. We prove that ventilation plays a very important role regarding volatile interactions, up to the point that some growth-inhibitory effects observed in closed environments switch to promoting ones when tested in vented conditions. This promoting activity seems to be related to the accumulation of squalene by T. harzianum. The VOC chambers proved to be an easy, homogeneous, flexible, and repeatable method, able to better select microorganisms with high biocontrol activity and to guide the future identification of new bioactive VOCs and their role in microbial interactions.

Effect of Cry Toxins on Xylotrechus arvicola (Coleoptera: Cerambycidae) Larvae.

The beetle Xylotrechus arvicola is a destructive pest in vineyards (Vitis vinifera) in the main wine-producing areas of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood-making galleries, thus damaging the plant both directly and indirectly; the latter through the proliferation of wood fungi, which can invade the inside of the plant, decreasing the quality and quantity of its production. The susceptibility of X. arvicola larvae to five coleopteran toxic Cry proteins (Cry1B, Cry1I, Cry3A, Cry7A, and Cry23/37) was evaluated under laboratory conditions in order to deepen the knowledge of the effect of these proteins on this insect throughout its biological development. Cry7Ab and Cry1Ba were the most effective in controlling X. arvicola larvae due to the significant reduction in larvae survival (32.9 and 25.9 days, respectively), and by causing serious alterations in the larvae during the remaining months of their development. The developmental stage of the prepupal and pupal stages was not affected by the previous ingestion of Cry proteins. The Cry proteins tested could be applied to control X. arvicola larvae since they were able to kill them and cause serious alterations in the larvae during the remaining months of development that followed. The data presented suggest that these Cry proteins can be used as bioinsecticides against the larvae of this insect, applying them only at the moment when the larvae hatch from the egg outside the grapevine wood (this would only be useful and justified if the economic threshold is exceeded) in order to avoid the rapid evolution of resistance against these toxins since not all of the larvae were killed and thus increase vine wood protection.

Insecticidal Properties of Ocimum basilicum and Cymbopogon winterianus against Acanthoscelides obtectus, Insect Pest of the Common Bean (Phaseolus vulgaris, L.).

The bean weevil, Acanthoscelides obtectus Say (Coleoptera: Chrysomelidae: Bruchinae), causes severe post-harvest losses in the common bean, Phaseolus vulgaris L. The control of this insect is still poor and involves the use of conventional insecticides. There is an increasing demand in the search for new active substances and products for pest control towards reduction of adverse effects on human health and the environment. The protection of grains with alternative products, such as essential oils, is a possible alternative to meet the needs described above. Therefore, this investigation evaluated the applications of basil, Ocimum basilicum, and citronella, Cymbopogon winterianus, essential oils for A. obtectus control. These essential oils significantly reduced the bean weight losses and the number of beans damaged by A. obtectus at higher doses than 60 or 120 µL/sample. The number of holes per bean did not differ between the doses of basil essential oil, not even at the dose of 60 µL, while it was higher at 120 µL, probably due to a lower capacity of movement of the insects treated with this dose and/or the oil's direct or indirect effects on the insects. Basil and citronella oils exhibited similar patterns of insecticidal activity over the insect, both directly in adult insects or indirectly over bean seeds. These essential oils affected the development of A. obtectus since the greatest doses applied on beans decreased the emergence of the bean weevil. The results prove the insecticidal capacity of the tested essential oils and hence their potential as active substances against A. obtectus in environmentally low risk pest control strategies. Supplementary trials should be conducted under real storage conditions.

Investigations of Trichoderma spp. and Beauveria bassiana as biological control agent for Xylotrechus arvicola, a major insect pest in Spanish vineyards.

Xylotrechus arvicola (Olivier) (Coleoptera: Cerambycidae) is an important pest in vineyards (Vitis vinifera) in the main wine-producing regions of Spain. Effective control of this pest is difficult due to the biology of this pest. Biological control agents (BCAs) have proven to be an effective tool in controlling and preventing the spread of a variety of plant pests and diseases. Consequently, the aim of the present study was to assess the capacity of different Trichodema spp., isolated from various vineyards and one commercial isolate of Beauveria bassiana Vuillemin (Hypocreales: Cordycipitaceae), as BCAs of X. arvicola. Isolates of Trichoderma spp. and one isolate of B. bassiana were evaluated against X. arvicola eggs, larvae and adults. Trichoderma harzianum and Trichoderma gamsii demonstrated a good ovicidal control, 100.0% with T. harzianum and over 92.0% with T. gamsii. These Trichoderma strains achieved an over 65.0% larval mortality and 87.5% adult mortality. B. bassiana was the most effective treatment against X. arvicola larvae. These results confirm that Trichoderma spp. can be used to inhibit egg development. In addition, Trichoderma spp. and B. bassiana can help to prevent larvae boring into vines and to kill adults. Therefore, Trichoderma spp., especially T. harzianum and T. gamsii, and B. bassiana can be considered as highly effective BCAs of X. arvicola in vineyards.

Field evaluation of 3-hydroxy-2-hexanone and ethanol as attractants for the cerambycid beetle pest of vineyards, Xylotrechus arvicola.

BACKGROUND: The beetle Xylotrechus arvicola (Coleoptera: Cerambycidae) is a serious pest of vineyards in the Iberian Peninsula. In previous work, the male beetles, but not females, were shown to produce (R)-3-hydroxy-2-hexanone, and female beetles were attracted to this compound in a laboratory bioassay. In this study, release rates of 3-hydroxy-2-hexanone from different dispensers were measured in the laboratory, and the attractiveness of these to X. arvicola adults was determined in trapping tests in three traditional wine-growing regions in Spain. RESULTS: As a result of laboratory experiments, for field experiments 3-hydroxy-2-hexanone was formulated as 100 µL in a polyethylene sachet (50 mm × 50 mm × 250 µm), and ethanol was formulated as 1 mL in a polyethylene press-seal bag (76 mm × 57 mm ×50 µm). Field catches were similar at all three study sites. Catches in traps baited with 3-hydroxy-2-hexanone alone were not significantly different from those in unbaited control traps, but catches in traps baited with 3-hydroxy-2-hexanone and ethanol in separate sachets, with 3-hydroxy-2-hexanone and ethanol in the same sachet or with ethanol alone were significantly greater than those in control traps. These results confirm that the beetles are attracted to ethanol, and the addition of 3-hydroxy-2-hexanone does not seem to make any difference. CONCLUSIONS: Attraction of females for the male-produced compound (R)-3-hydroxy-2-hexanone has been observed in laboratory but not in field experiments. Traps baited with ethanol are highly attractive to both sexes of adults of X. arvicola, and these can be used for improved monitoring of the adult emergence and for population control by mass trapping. © 2016 Society of Chemical Industry.

Reproductive Patterns of Xylotrechus arvicola (Coleoptera: Cerambycidae), an Emerging Pest of Grape-Vines, under Laboratory Conditions.

Xylotrechus arvicola (Olivier) is an emerging pest in vineyards ( Vitis vinifera ) in the Iberian Peninsula. Its reproductive biology has been studied in the laboratory in order to develop pest-control measures. Obtained results show that the oviposition period is significantly longer in wild females (16.6 ± 2.9 d) than in laboratory females (9.7 ± 1.3 d), but there are no significant differences in the egg-hatching periods between the wild and the laboratory females. Fecundity is significantly higher in laboratory females (93.9 ± 12.1 eggs per female) than in wild females (56.8 ± 9.2 eggs per female). On the other hand, viability (percentage of viable eggs per female) is significantly higher in wild females (53.7 ± 6.6%) than in laboratory females (22.9 ± 3.6%). Wild females lay fewer eggs over a longer period, while laboratory females concentrate on laying in the first 6 d. X. arvicola females (wild and laboratory) lay the highest number of eggs on the sixth day. The fecundity and viability of eggs are extended over a longer period in wild females than in laboratory females. So X. arvicola is a species in which larvae feed directly affects reproductive patterns. These results suggest that, when larvae feed directly from the natural host, the fecundity period and the viability of eggs increase. So the selection of a host plant could be influenced by the composition of the wood. This behavior of the species can also help to advance knowledge of the biology and ecology of this pest, to be applied in integrated control.

Development of a qPCR Strategy to Select Bean Genes Involved in Plant Defense Response and Regulated by the Trichoderma velutinum - Rhizoctonia solani Interaction.

Bean production is affected by a wide diversity of fungal pathogens, among them Rhizoctonia solani is one of the most important. A strategy to control bean infectious diseases, mainly those caused by fungi, is based on the use of biocontrol agents (BCAs) that can reduce the negative effects of plant pathogens and also can promote positive responses in the plant. Trichoderma is a fungal genus that is able to induce the expression of genes involved in plant defense response and also to promote plant growth, root development and nutrient uptake. In this article, a strategy that combines in silico analysis and real time PCR to detect additional bean defense-related genes, regulated by the presence of Trichoderma velutinum and/or R. solani has been applied. Based in this strategy, from the 48 bean genes initially analyzed, 14 were selected, and only WRKY33, CH5b and hGS showed an up-regulatory response in the presence of T. velutinum. The other genes were or not affected (OSM34) or down-regulated by the presence of this fungus. R. solani infection resulted in a down-regulation of most of the genes analyzed, except PR1, OSM34 and CNGC2 that were not affected, and the presence of both, T. velutinum and R. solani, up-regulates hGS and down-regulates all the other genes analyzed, except CH5b which was not significantly affected. As conclusion, the strategy described in the present work has been shown to be effective to detect genes involved in plant defense, which respond to the presence of a BCA or to a pathogen and also to the presence of both. The selected genes show significant homology with previously described plant defense genes and they are expressed in bean leaves of plants treated with T. velutinum and/or infected with R. solani.

Vitrectomia en la uveitis / Vitrectomy in uveitis

La vitrectomia es una alternativa de la inflamacion en casos seleccionados de uveitis activas anteriories, posteriores e intermedias que por diversos motivos no cede adecuadamente al tratamiento medico, o para etapas cicatriciales mas tardias en las que la vitrectomia ayuda a resolver complicaciones y secuelas propias de esta enfermedad. Las posiblidades de exito son menores en los casos severamente avanzadas de este ultimo grupo. Se recalca sobre la etiologia de los procesos uveiticos que condujeron a la vitrecotmia y, en especial, las enfermedades parasitarias como toxocariasis, toxoplasmosis y cisticercosis. Tambien se recalca sobre la catarata que acompana a procesos de uveitis. Se presentan los hallazgos clinicos, algunos detalles sobre la tecnica de la vitrectomia, sus complicaciones y finalmente los resultados funcionales. Se realizaron 61 vitrectomias en uveitis, 24 de ellas en la endoftalmitis de la toxocariasis ocular. En esta ultima, luego de la vitrectomia, los resultados visuales fueron mejoria en 67%; vision igual a la preoperatoria en 13% y peor en 20%, que tambien fueron fracasos anatomicos. No parece recomendable la realizacion de vitrectomias precoces en casos seleccionados de uveitis por los mejores resultados obtenidos y antes de que su evolucion natural conduzca a estados irreversibles. La vitrectomia y su seguimiento deben ser cuidados por los peligros naturales de esta cirugia

Síndrome de necrosis retiniana aguda / Acute retinal necrosis syndrome

La necrosis retiniana aguda comienza a aparecer en países diferentes a los Estados Unidos. quizá con características especiales. La presente comunicación se refiere a un joven de 13 años, cuyo ojo izquierdo estaba afectado por la enfermedad y luego de un mes perdió totalmente la visión por ese ojo a causa de plastrones exudativos superiores, a fenómenos de periarteritis, papilitis y edema macular; además existía un desprendimiento exudativo inferior. La uveitis anterior presente mejoró mientras empeoraba la uveitis posterior y luego comienza una fase de cicatrización pigmentaria con fibrosis subretiniana y desaparición del desprendimiento. Por carencia de acyclovir, el paciente fue tratado con esteroides, con notable mejoría del cuadro y para sorpresa se inicia una recuperación visual. No se ha observado ataque al ojo opuesto luego de diez meses de evolución

La fotocoagulacion panretiniana con laser de argon en la retinopatia diabetica proliferativa / The panretinal photocoagulation with argon laser in the proliferative diabetic retinopathy

El objetivo del presente trabajo es el de presentar el resutlado de la regresion clinica de la neovascularizacion en 114 ojos afectado de retinopatia diabetica proliferativa, luego del tratamiento con laser azul-verde de argon, mediante la fotocoagulacion panretiniana. La experiencia se desarrollo en 114 ojos de 60 pacientes diabeticos tipos I y II con un tiempo promedio de evolucion de esta enfermedad de 14 anos con edades comprendidas entre 17 y 78 anos y distribuidos por sexos asi: 36 hombres y 24 mujeres. Se hallaron alteraciones oculares asociadas, tales como catarata, glaucoma y rubeosis del iris. Se comentan los factores de riesgo hallados, siguiendo la clasificacion del Diabetic Retinopaty Study Group. La tecnica de la fotocoagulacion panretiniana empleada en esta serie, fue la suegerida por el mismo DRS, igual que la valoracion de los resultados, los cuales, en un reducido numero de pacientes, no fueron exitosos, observandose algunas complicaciones posteriores al procedimiento.