Insights into the mode of action of the two-peptide lantibiotic lichenicidin

Lantibiotics are promising candidates to address the worldwide problem of antibiotic resistance. They belong to a class of natural compounds exhibiting strong activity against clinically relevant Gram-positive bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). Lichenicidin is a class II two-peptide lantibiotic. The presence of the two mature peptides, Bliα and Bliβ, is necessary for full activity against target bacteria. This work aims at clarifying the synergistic activity of both peptides in their interaction with the target membranes. The effect of lichenicidin was tested against S. aureus cells and large unilamellar vesicles. Lichenicidin increases the net surface charge of S. aureus, as shown by zeta-potential measurements, without reaching electroneutralization. In addition, lichenicidin causes cell surface perturbations that culminate in the leakage of its internal contents, as observed by atomic force microscopy. Bliα seems to have low affinity for S. aureus, however, it contributes to increase the affinity of Bliβ, because together they present higher affinity than separately. In contrast, Bliα seems to provide an anchoring site for lichenicidin in lipid II-containing membranes. Interestingly, Bliβ alone can induce high levels of membrane leakage, but this effect appears to be faster in the presence of Bliα. Based on this information, we propose a mechanism of action of lichenicidin.

Enhanced ionic conductivity in poly(vinylidene fluoride) electrospun separator membranes blended with different ionic liquids for lithium ion batteries

Electrospun poly(vinylidene fluoride) (PVDF) fiber membranes doped with different ionic liquids (ILs) and sharing the same anion were produced and their potential as separator membranes for battery applications was evaluated. Different types of ILs containing the same anion, bis(trifluoromethylsulfonyl)imide [TFSI]^-, were used with IL concentrations ranging between 0 and 15 wt% The morphology, microstructure, thermal and electrical properties (ionic conductivity and electrochemical window) of the membranes were evaluated. The presence of ILs in the PVDF polymer matrix influences the fiber diameter and the content of the polar β phase within the polymer, as well as the degree of crystallinity. The thermal stability of the membranes decreases with the incorporation of IL. Impedance spectroscopy tests show a maximum ionic conductivity of 2.8 mS.cm^-1 for 15% of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) at room temperature. The electrochemical stability of the samples ranges from 0.0 to 6.0 V. When evaluated as battery separator membranes in C-LiFePO₄ half-cells, a maximum discharge capacity of 119 mAh.g^-1 at C-rate was obtained for the PVDF membrane with 15% [Emim][TFSI], with a coulombic efficiency close to 100%. The results demonstrate that the produced electrospun membranes are suitable for applications as separators for lithium ion batteries (LIBs).

Spatial Distribution of Adults of Triozoida limbata (Enderlein) (Hemiptera: Triozidae) in Guava Plants

The psyllid Triozoida limbata (Enderlein) (Hemiptera: Triozidae) is a major pest in guava, feeding primarily on new shoots. Despite its importance, there are no studies on the spatial distribution of T. limbata on guava. Such studies are needed to establish sequential sampling plans for decision making in pest control. Thus, an experiment was carried out in a 9-year-old commercial guava orchard divided into 100 sampling units or plots. Double-sided yellow sticky traps were placed on one plant per plot (sample unit) to capture and monitor T. limbata adults from April 2011 to May 2012. To determine the insect distribution in the area, we calculated the variance-to-mean ratio index (I), the Morisita index (I δ ), Green's coefficient (Cx), and the k exponent of the negative binomial distribution. Most of the samples showed that the adults had a moderate to highly aggregated distribution. Statistical models were also used to study the pest spatial distribution by fitting the number of adults captured to the Poisson and negative binomial distributions. The negative binomial distribution model best fitted the data of the number of adult psyllids captured by the traps, which is consistent with an aggregated distribution.

'Candidatus Liberibacter asiaticus' Titers in Citrus and Acquisition Rates by Diaphorina citri Are Decreased by Higher Temperature

'Candidatus Liberibacter asiaticus' is the most prevalent Liberibacter sp. associated with huanglongbing (HLB) in Brazil. Within São Paulo state (SP), HLB has spread more rapidly to and reached higher incidence in regions with relatively mild (cooler) summer temperatures. This suggests that climate can influence disease spread and severity. 'Ca. L. asiaticus' titers on soft, immature leaves from infected 'Valencia' sweet orange plants exposed to different temperature regimes and adult Diaphorina citri fed for 48 h on these plants for 'Ca. L. asiaticus' acquisition were determined by quantitative polymerase chain reaction in two experiments. The first experiment included plants with three levels of infection, three incubation periods (IPs), and air temperatures favorable (14.6 to 28°C) and unfavorable (24 to 38°C) to 'Ca. L. asiaticus'. The second included plants with severe late-stage infections, 10 IPs (based on 3-day intervals over 27 days), and three air temperature regimes (12 to 24, 18 to 30, and 24 to 38°C). Overall, 'Ca. L. asiaticus' titers and the percentages of 'Ca. L. asiaticus'-positive psyllids were lower in plants maintained at the warmer temperature regime (24 to 38°C) than in plants maintained in the cooler regimes. The results suggest that the lower incidence and slower spread of 'Ca. L. asiaticus' to warmer regions of SP are related to the influence of ambient temperatures on titers of 'Ca. L. asiaticus' in leaves.

Effect of Low-Temperature Storage on Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae)

We evaluated the effects of constant low-temperature storage on Diaeretiella rapae (McIntosh) (Braconidae, Aphidiinae). Diaeretiella rapae mummies were stored at 5 ± 1°C for 0-36 days. The percentage of D. rapae emergence varied (100-83%) after 0-32 days of storage. After 32 days, emergence reduced to 55%. According to our Probit analysis, 50% mortality (LT50) of the population of D. rapae was reached after 40 days of storage at 5°C. Storage for up to 32 days did not negatively affect emergence and survival. Cold exposure of D. rapae for 36 days did not influence morphological malformations, sex ratio, and emergence of the F1 generation. After 4-36 days of storage, D. rapae showed a gradual decrease in emergence, longevity, reproductive capacity, and F1 sex ratio. Diaeretiella rapae can be stored for up to 24 days at 5°C, at which time the percentage of parasitism and the F1 sex ratio remain above 38% and at 0.50, respectively.

Spatial distribution of Euschistus heros (F.) (Hemiptera: Pentatomidae) in soybean

Soybean bugs are major crop pests that cause significant reduction in harvest yield and influence grain quality. The aim of this study was to verify the spatial distribution of Euschistus heros (F.) (Hemiptera: Pentatomidae) in conventional and transgenic soybean cultivars. The experiment was conducted during the 2010-2011 crop season in UNESP/FCAV, Jaboticabal, SP, Brazil, in two fields of 10,000-m(2) area that were subdivided into 100 plots (10 m × 10 m). The cultivars sown were M 7908 RR and its isoline M-SOY 8001. The number of the first to fifth instars and the number of adults were determined. To evaluate insect dispersion in the area, the following indices were used: variance/mean ratio, Morisita index, Green coefficient, and the k exponent of the negative binomial distribution. To study probabilistic models to describe the spatial distribution of the insects, the adjustments of the Poisson and negative binomial distributions were tested. The first to third instars showed aggregated spatial distribution, whereas the fourth and fifth instars, and adults, isolated or grouped, showed variation in the arrangement, ranging from moderately aggregated to randomly dispersed. During the adjustment of probability distributions, the negative binomial distribution model showed adjustment for the first to third instars, fourth and fifth instars, adults, and fourth and fifth instars plus adults.

Sequential sampling plan for Tenuipalpus heveae Baker (Acari: Tenuipalpidae) on rubber tree

The objective of the present study was to develop a sequential sampling plan for the decision-making process to control Tenuipalpus heveae Baker (Acari: Tenuipalpidae), an important pest of the rubber tree crop. The experimental area was represented by 1,000 plants of the RRIM 600 clone divided in 100 plots with 10 plants each. Leaves were collected and the number of mites determined under laboratory conditions. The sequential sampling plan was developed in accordance with the Sequential Test Likelihood Ratio. The value 0.10 was pre-established for α and β representing type I and type II errors, respectively. The level of control adopted was six mites per 12 cm(2). The operating characteristic curve and the curve of maximum expected sample were determined. Two lines were generated: the upper one, when the condition for chemical control is recommended (S1 = 23.3080 + 2.1972); and the lower, when chemical control is not recommended (S0 = -23.3080 + 2.1972). Sample size for the decision-making process to control T. heveae requires 6 to 18 plants.

First Report of Tomato yellow spot virus Infecting Leonurus sibiricus in Brazil

In Brazil, serious epidemics of begomovirus diseases have been successively reported since the mid-90s, among them those caused by Tomato yellow spot virus (ToYSV) (1). In July 2009 and October 2010, high incidences (40 to 60%) of plants of the weed Leonurus sibiricus (Lamiaceae) exhibiting symptoms of yellow leaf mosaic were found near soybean (Glycine max) crops within the municipalities of Marechal Cândido Rondon and Tapejara, in the states of Paraná and Rio Grande do Sul. Leaves from 21 symptomatic and seven asymptomatic L. sibiricus plants were collected from both localities and tested for the presence of begomovirus. Total DNA was extracted from each sample using Dneasy Plant Mini Kit (Qiagen) and submitted to PCR using begomovirus universal oligonucleotides PAL1v1978/PAR1c496 (3). One fragment of approximately 1,300 bp comprising the 5'-region of the replication-associated protein (Rep) gene, the entire intergenic region (IR), and the 5'-region of the coat protein (CP) gene was amplified from all symptomatic, but not from asymptomatic samples. Amplified fragments corresponding to all isolates were directly sequenced and nucleotide sequence comparisons indicated 98 to 99% nucleotide identity among themselves, and 93 to 94% identity with the corresponding nucleotide sequences for the DNA-A of the begomovirus ToYSV (GenBank Accession No. DQ336350). To confirm these results, the full genome of ToYSV Mc-7 isolated from Marechal Cândido Rondon was cloned and completely sequenced by primer walking (Macrogen Seoul, Korea). The DNA-A of ToYSV Mc-7 (JX513952) was 2,592 nt long and shared 92 and 91% identity with isolates of ToYSV from Argentina (FJ538207) and Brazil (DQ336350), respectively. The DNA-B of ToYSV Mc-7 (JX513952) was 2,568 nt long and shared 91% identity with DNA-B of a Brazilian isolate of ToYSV (DQ336351). The ToYSV Mc-7 isolate is a new strain named Tomato yellow spot virus (Brazil:Marechal Candido Rondon 7:Leonurus:2009) [ToYSV-(BR:MCR7:Le:09)]. To demonstrate pathogenicity, virus-free adults of Bemisia tabaci biotype B were confined on symptomatic L. sibiricus plants for a 48-h acquisition period. The whiteflies were then transferred to healthy L. sibiricus, bean (Phaseolus vulgaris), soybean, and tomato (Solanum lycopersicum) plants. L. sibiricus plants showed the original symptoms on the leaves (five symptomatic plants, seven inoculated plants), whereas bean (3/7), soybean (4/10), and tomato plants (5/10) exhibited mild yellow leaf mosaic. The infection in these symptomatic plants was confirmed by PCR with oligonucleotides PAL1v1978/PAR1c496 (3) and subsequent direct nucleotide sequencing of the 5'-region of the CP gene, which confirmed the identity of the transmitted virus as ToYSV. ToYSV was first reported infecting tomato plants in Minas Gerais state, Brazil (1). Recently, ToYSV was found infecting bean and soybean plants in northwestern Argentina (2). Because L. sibiricus is a weed widely distributed throughout Brazil, and the ToYSV vector B. tabaci is also common, this weed may become a potential source of inoculun of ToYSV to bean, soybean, and tomato crops. To our knowledge, this is the first report of L. sibiricus as a natural host of ToYSV. References: (1) R. F. Calegario et al. Pesq. Agropec. Bras. 42:1335, 2007. (2) P. E. Rodríguez-Pardina et al. Ann. Appl. Biol. 158:69, 2011. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993.

Influence of chlorine added to drinking water during the preslaughter feed withdrawal on microbiology and morphology of the broiler gastrointestinal tract

The objective of this experiment was to test the effects of the addition of chlorine to broiler drinking water during a 12-h preslaughter feed withdrawal period on reduction of the quantities of microorganisms, such as Escherichia coli and enterococci, in broiler crops and ceca. Reduction of these microorganisms would likely also reduce contamination of broiler meat by pathogenic bacteria during processing. It was also investigated if the chlorine caused some intestinal damage that could disseminate the microorganisms to the carcass. A total of 40 Cobb male broilers were used. Samples of crop and cecal content were collected for microbiological analysis, and duodenum and jejunum were used for morphological analysis from 10 birds in each treatment. The most probable number (MPN) of E. coli and enterococci in the collected samples of crop and ceca and the measure of the free residual chlorine in water were determined. The scanning electron microscopy from duodenum and jejunum was used to illustrate the mucosa integrity. The chlorine added to water was efficient in reducing the quantities of microorganisms in broiler crops and improved the integrity of the mucosa. Therefore, preslaughter feed withdrawal should be coupled with crop disinfection, because preslaughter feed withdrawal increases the MPN of enterococci and E. coli in broiler crops. So, it presents a higher risk for carcass contamination during slaughterhouse processing and, consequently, a higher risk for public health.

A Sida sp. Is a New Host for "Candidatus Phytoplasma brasiliense" in Brazil

Sida is a genus of flowering herbs in the family Malvaceae, which includes several species that are weeds in Brazil. Plants of a Sida sp. exhibiting symptoms characterized by stunting, chlorosis, small leaves, and witches'-broom, indicative of infection by phytoplasmas, were found in a field previously cultivated with tomato, located in the region of Campinas, State of São Paulo, in December 2008. To demonstrate the presence of phytoplasmas in diseased tissues, DNA was extracted from shoots and leaves from three symptomatic and eight asymptomatic plants. Nested PCR was performed using primers P1/Tint followed by primer pair R16F2n/R16R2 (1). DNA fragments of 1.2 kb, corresponding to 16S rDNA, were amplified only for DNA from two symptomatic samples. Phytoplasma identification was initially carried out by restriction fragment length polymorphism (RFLP) analysis through digesting the PCR products with the restriction enzymes AluI, HhaI, HaeIII, HpaII, MseI, and RsaI. The two phytoplasma isolates found to be infecting a Sida sp. showed identical RFLP patterns, which were indistinguishable from the phytoplasma previously reported in association with hibiscus (Hibiscus rosa-sinensis) witches'-broom in Brazil (2). Nucleotide sequence alignment revealed that 16S rDNA of both phytoplasma isolates found in a Sida sp. (GenBank Accession No. HQ230579) shared 99.9% sequence similarity with 16S rDNA from hibiscus witches'-broom phytoplasma (HibWB) (GenBank Accession No. AF147708). HibWB is the representative of the 16SrXV group and it was proposed as a putative species nominated "Candidatus Phytoplasma brasiliense" (2). The disease is frequently observed in hibiscus plants used as ornamentals in the states of São Paulo (4) and Rio de Janeiro (2). "Ca. Phytoplasma brasiliense" has only been reported in Brazil to be infecting hibiscus (2,4) and periwinkle (Catharanthus roseus) (3). The presence of a phytoplasma belonging to group 16SrXV in a Sida sp. expands its natural host range. The role of this weed as a potential source of inoculum for crops should be investigated. References: (1) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) H. G. Montano et al. Int. J. Syst. Evol. Microbiol. 51:1109, 2001. (3) H. G. Montano et al. Plant Dis. 85:1209, 2001. (4) E. G. Silva et al. Summa Phytopathol. 35:234, 2009.

First Report on the Susceptibility of Sweet Pepper Crops to Tomato chlorosis virus in Brazil

In June of 2009, sweet pepper (Capsicum annuum cvs. Elisa and Prador) plants exhibiting interveinal chlorosis, some necrosis, and mild upward leaf curling on the intermediate leaves were found in three protected crops in the municipality of São Miguel Arcanjo, São Paulo state, Brazil. Incidence of symptomatic plants varied from 70 to 100%. Abundant whitefly adults were seen in all crops. Initially, total DNA was separately extracted from seven symptomatic plants and submitted to a PCR reaction using the universal primer pairs PAL1v1978/PAR1c496 and PBL1v2040/PCRc1 for begomovirus (3). The results were negative. The same samples were also analyzed for infection with Tomato infectious chlorosis virus (TICV) and Tomato chlorosis virus (ToCV) (genus Crinivirus, family Closteroviridae). Total RNA was extracted separately from leaves of each symptomatic plant and used for one-step reverse transcription (RT)-PCR using the HS-11/HS-12 primer pair, which amplifies a fragment of 587 bp from the highly conserved region of the heat shock protein (HSP-70) homolog gene reported for TICV and ToCV (1). The RT-PCR product was subsequently tested by nested-PCR for single detection of TICV and ToCV using primer pairs TIC-3/TIC-4 and ToC-5/ToC-6, respectively (1). Only one fragment of approximately 463 bp was amplified from the five plants with the primer pair specific for ToCV. No amplification was obtained with the primers specific for TICV. Four purified amplicons of 463 bp were directly sequenced in both directions. Sequence comparisons of the 419-bp consensus sequence, encompassing nucleotides 750 and 1,167 of the HSP-70 homolog gene, revealed 98% identity with the reported sequences of tomato infecting isolates of ToCV from Brazil (GenBank Accession No. EU868927) and the United States (GenBank Accession No. AY903448). Virus-free adults of Bemisia tabaci biotype B were confined on symptomatic pepper leaves for a 48-h acquisition access period. Twenty adults were transferred to one plant of sweet pepper cv. Magda for a 24-h inoculation access period. The sweet pepper plant exhibited the original symptoms on the leaves 67 days after inoculation under greenhouse conditions. Infection by ToCV was confirmed by RT-PCR. The susceptibility of sweet pepper plants to ToCV was previously reported in Spain (2), whereas in the United States, this species was experimentally found as nonhost for this virus (4). Further studies are needed to better understand the variable susceptibility of sweet pepper to ToCV. References: (1) C. I. Dovas et al. Plant Dis. 86:1345, 2002. (2) G. Lozano et al. Plant Dis. 88:224, 2004. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) W. M. Wintermantel et al. Plant Dis. 90:814, 2006.

Intraoperative bleeding during vitrectomy for diabetic tractional retinal detachment with versus without preoperative intravitreal bevacizumab (IBeTra study)

AIMS

To compare the amount of intraoperative intraocular bleeding in patients with diabetes with macula-involving tractional retinal detachment (TRD) undergoing pars plana vitrectomy (PPV) with and without preoperative intravitreal bevacizumab (IVB) injection.

METHODS

An institutional study was carried out with consecutive patients with diabetic retinopathy and macula-involving TRD of recent (3 months) onset who were randomly assigned to PPV only (PPV group) or PPV combined with one IVB (1.5 mg/0.06 ml) injection 2 weeks prior to surgery (bevacizumab (BEV)/PPV group). All patients underwent 23-gauge PPV 3 weeks after baseline. The main outcome measure was erythrocyte count in the fluid retrieved from the vitrectomy cassette using a Neubauer counting chamber.

RESULTS

The study included 20 patients. The mean erythrocyte count was 14,865x10(3) (SD 19,332x10(3); median 4,500x10(3)) cells in the BEV/PPV group, and 176,240x10(3) (SD 108,375x10(3); median 166,600x10(3)) cells in the PPV group. The mean erythrocyte count was significantly lower in the BEV/PPV group than in the PPV group (p<0.0001). No major adverse events were identified.

CONCLUSION

Preoperative IVB injection was associated with reduced intraocular bleeding during 23-gauge PPV for diabetic macula-involving TRD. Further studies are needed to confirm our preliminary findings.

TRIAL REGISTRATION NUMBER

NCT00690768.

First Report of Tomato chlorosis virus Infecting Tomato Crops in Brazil

During 2006 and 2007 in the region of Sumaré, state of São Paulo, Brazil, surveys were done on tomato (Solanum lycopersicum L.) virus diseases in three open field-grown crops. The data revealed low incidence (0.25 to 3.42%) of randomly distributed plants exhibiting interveinal chlorosis and some necrosis on the basal leaves. Symptoms were only observed on old fruit-bearing plants. Preliminary analysis of thin sections of symptomatic leaves from one plant by transmission electron microscopy revealed the presence of aggregates of thin, flexible, and elongated particles in some phloem vessels, suggesting infection with a member of the genus Crinivirus, family Closteroviridae. Total RNA was extracted separately from leaves of 10 symptomatic plants and used for one-step reverse transcription (RT)-PCR using the HS-11/HS-12 primer pair, which amplifies a fragment of 587 bp from the highly conserved region of the heat shock protein (HSP-70) homolog gene reported for Tomato infectious chlorosis virus (TICV) and Tomato chlorosis virus (ToCV) (1). The RT-PCR product was subsequently tested by nested-PCR for single detection of TICV and ToCV using primer pairs TIC-3/TIC-4 and ToC-5/ToC-6, respectively (1). Only one fragment of approximately 463 bp was amplified from 7 of the 10 plants with the primer pair specific for ToCV. No amplification was obtained with the primers specific for TICV. Two amplicons of 463 bp were purified and directly sequenced in both directions. Sequence comparisons of the 463-bp consensus sequence (GenBank Accession No. EU868927) revealed 99% identity with the reported sequence of ToCV from the United States (GenBank Accession No. AY903448) (3). Virus-free adults of Bemisia tabaci biotype B confined on symptomatic tomato leaves for a 24-h acquisition access period were able to transmit the virus to healthy tomato plants, which reproduced the original symptoms on the bottom leaves 65 days after inoculation under greenhouse conditions. Infection from transmission was confirmed by RT-PCR using the HS-11/HS-12 primer pair. In addition to B. tabaci biotype B, the greenhouse whitefly, Trialeurodes vaporariorum, has also been reported as a vector of ToCV, although it is less efficient than the B. tabaci biotype B in transmission of this virus (4). T. vaporariorum, which was previously considered limited to greenhouses, was recently reported in tomato and green bean (Phaseolus vulgaris L.) crops under field conditions in São Paulo State (2). Therefore, it might also contribute to the spread of ToCV in tomato crops in São Paulo. To our knowledge, this is the first report of ToCV in Brazil and South America. References: (1) C. I. Dovas et al. Plant Dis.86:1345, 2002. (2) A. L. Lourenção et al. Neotrop. Entomol. 37:89, 2008. (3) W. M. Wintermantel et al. Arch. Virol. 15:2287, 2005. (4) W. M. Wintermantel and G. C. Wisler. Plant Dis. 90:814, 2006.

Effect of Citrus Sudden Death on Yield and Quality of Sweet Orange Cultivars in Brazil

Citrus sudden death (CSD) has greatly affected sweet orange cultivars grafted on Rangpur lime in São Paulo and Minas Gerais States, Brazil. To characterize and quantify CSD damage, fruit yield and quality were assessed in each combination of sweet orange cultivar (Hamlin, Pera, Natal, and Valencia), age class (3 to 5, 6 to 10, and 11 to 15 years old), and CSD severity class (0 = no symptom, 1 = initial symptoms, and 2 = severe symptoms). For each combination, 10 trees were harvested and 20 fruit were taken for quality analysis. Damage was characterized by reduction of: (i) total weight of fruit/tree (36 and 67% for severity class 1 and 2, respectively), (ii) number of fruit/tree (27 and 55%), (iii) fruit size (13 and 25% in diameter and height [stem to styler distance]), (iv) fruit weight (32 and 56%), (v) total soluble solids (TSS)/fruit (18 and 42%), and increase of (vi) Brix (14 and 34%), (vii) acidity (16 and 41%), and (viii) TSS/90-lb. box (21 and 33%). There was no alteration on Brix/acidity ratio and percentage of juice on fruit of affected trees. Sweet orange cultivars did not differ in percentage of reduction or increase of all yield and quality variables, with the exception of Pera, which expressed increases of Brix and acidity. For more severe affected trees, the youngest plants showed a higher reduction in fruit number/tree, whereas plants 6 to 10 years old showed a higher increase in fruit acidity and TSS/box. However, no differences in percentage of reduction or increase for other variables were observed among different age classes. The damage to the above probably was associated with reduced water absorption capacity of CSD-affected trees.

Intravitreal triamcinolone versus bevacizumab for treatment of refractory diabetic macular oedema (IBEME study)

BACKGROUND/AIMS

The aim of this study was to compare the morphological and visual acuity outcomes associated with a single intravitreal injection of triamcinolone acetonide versus bevacizumab for the treatment of refractory diffuse diabetic macular oedema.

METHODS

Twenty-eight patients were randomly assigned to receive a single intravitreal injection of either 4 mg/0.1 ml triamcinolone acetonide or 1.5 mg/0.06 ml bevacizumab. Comprehensive ophthalmic evaluation was performed at baseline and at weeks 1, 4, 8 (+/-1), 12 (+/-2) and 24 (+/-2) after treatment. Main outcome measures included central macular thickness measured with optical coherence tomography (OCT) and best corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity.

RESULTS

Twenty-six patients (26 eyes) completed all study visits (two patients missed two consecutive study visits). Central macular thickness was significantly reduced in the intravitreal triamcinolone group compared with the bevacizumab group at weeks 4, 8, 12 and 24 (p<0.05). Logarithm of the minimum angle of resolution (LogMAR) best-corrected visual acuity was significantly higher at weeks 8 (0.69; approximately 20/100(+1)) and 12 (0.74; 20/100(-2)) in the intravitreal triamcinolone group compared with the bevacizumab group (weeks 8 (0.83; approximately 20/125(-1)) and 12 (0.86; 20/160(+2))) (p<0.05). Significant change from baseline in mean intraocular pressure (mmHg) was seen at week 4 (+2.25) only in the intravitreal triamcinolone group (p<0.0001). No patient had observed cataract progression during the study.

CONCLUSIONS

One single intravitreal injection of triamcinolone may offer certain advantages over bevacizumab in the short-term management of refractory diabetic macular oedema, specifically with regard to changes in central macular thickness. The actual clinical relevance of our preliminary findings, however, remains to be determined in future larger studies.

An Experimental Inoculation System to Study Citrus-Xylella fastidiosa Interactions

Difficulties in reproducing the citrus variegated chlorosis (CVC) disease symptoms in experimental plants have delayed implementation of studies to better understand the essential aspects of this important disease. In an extensive study, cultivars of sweet orange (Citrus sinensis) were inoculated with Xylella fastidiosa using procedures that included root immersion, and stem absorption, pricking, or infiltration of the inoculum into plants of different ages. Inoculum consisted of 5-day-old cultures or cell suspensions of CVC strain 9a5c diluted in phosphate-buffered saline. Inoculated plants and controls were grown, or transferred just after inoculation, to 5-liter pots or 72-cell foam trays. Approximately 4, 5, 9, and 12 months after inoculation, leaves were collected and processed for polymerase chain reaction analysis or X. fastidiosa isolation on BCYE agar medium. Root immersion and stem inoculation of 4- and 6-month-old plants resulted in low percentages of symptomatic (0 to 7%) and plants positive by isolation (0 to 9%). Pinpricked or injected stems of 1-month-old seedlings resulted in high percentages of plants symptomatic (29 and 90% in Pera Rio, 75, 59, and 83% in Valencia, and 77% in Natal) or positive by isolation (26 and 93% in Pera Rio, 98, 96, and 83% in Valencia, and 77% in Natal). In foam trays, the seedlings grew less, the incubation period was shorter, and disease severity was higher than in pots. This system allows testing of higher numbers of plants in a reduced space with a more precise reproduction of the experimental conditions.

Using Geostatistical Analysis to Evaluate the Presence of Rotylenchulus reniformis in Cotton Crops in Brazil: Economic Implications

In recent years, the productivity of cotton in Brazil has been progressively decreasing, often the result of the reniform nematode Rotylenchulus reniformis. This species can reduce crop productivity by up to 40%. Nematodes can be controlled by nematicides but, because of expense and toxicity, application of nematicides to large crop areas may be undesirable. In this work, a methodology using geostatistics for quantifying the risk of nematicide application to small crop areas is proposed. This risk, in economic terms, can be compared to nematicide cost to develop an optimal strategy for Precision Farming. Soil (300 cm(3)) was sampled in a regular network from a R. reniformis-infested area that was a cotton monoculture for 20 years. The number of nematodes in each sample was counted. The nematode number per volume of soil was characterized using geostatistics, and 100 conditional simulations were conducted. Based on the simulations, risk maps were plotted showing the areas where nematicide should be applied in a Precision Farming context. The methodology developed can be applied to farming in countries that are highly dependent on agriculture, with useful economic implications.

[The meaning of living with chronic renal failure]

This study is part integrant of result of my inquietude in relationship to the ill person with renal chronic illness, subject of my dissertation. For that, I used qualitative research phenomenological modality, that allowed me to understand the ill and to answer my interrogation: What is to be a renal chronically ill person? The analysis of descriptions revealed the look of the renal chronically ill in relationship with the disease, treatment and the possibility of cure. However in this study I emphasize the meaning to live with chronic renal failure.

Statistical methodology: VII. Q-methodology, a structural analytic approach to medical subjectivity

Q-methodology is a relatively unknown tool to medical researchers, that uses a mixed quantitative/qualitative statistical technique known as by-person factor analysis to study subjectivity. Q-methodology allows the grouping of individuals according to their subjective feelings about a topic, without requiring preconceived ideas regarding the structure of those subjective feelings. Q-methodology is demonstrated using a study in which attitudes of emergency medicine residents toward computer education are explored systematically and classified in terms of statistically distinct factor viewpoints. In this example, Q-methodology identifies 4 attitude groups, as related to computers and computer education: 1) interested, eager to learn; 2) frustrated and interested, but with reservations; 3) interested mainly in benefits, willing to expend minimal effort; and 4) knowledgeable, independent learner. Q-methodology can be used to determine the structure of attitudes on a subjective topic, often yielding new insights.

Haematological and biochemical alterations in leprosy patients already treated with dapsone and MDT

Dapsone (DDS) is useful in the treatment of a number of inflammatory conditions which are characterized by neutrophil infiltration. It is the drug of choice for the treatment of leprosy and prophylaxis of malaria. Haematological side effects of methaemoglobinaemia and haemolysis have been long recognized. However, the frequency and severity of these side effects in patients already treated with DDS as a single drug or as part of a multidrug therapy (MDT) have not been well documented. We report herein an investigation of the effect of dapsone long-term treatment on the haematological and biochemical alterations in leprosy patients undergoing dapsone as a single drug (DDS group) or as part of a multidrug therapy in combination with rifampin and clofazimine (MDT group). Methaemoglobinaemia and haemolytic anaemia were the principal side effects observed. Reticulocytes were found to be elevated (> 1.5%) in 90% of the patients. Heinz bodies were also detected (6.6% of the patients). The osmotic fragility test showed a reduction in cell resistance and in the evaluation of white cells a severe eosinophilia was found. Hepatic, pancreatic and renal evaluation by the determination of biochemical parameters showed rare and occasional changes of no apparent clinical significance. We conclude that haematological side effects of dapsone are significant even at doses currently used to treat leprosy (100 mg/day) and that rifampin and clofazimine do not increase the incidence of these effects during long-term treatment.

Heart muscle cells acutely infected with Trypanosoma cruzi: characterization of electrophysiology and neurotransmitter responses

Primary cell cultures of mouse ventricular myocardium were infected with Trypanosoma cruzi, to study the consequences of T. cruzi-muscle cell interaction on the rate of spontaneous contractions, on the responses to norepinephrine, and on action potential parameters. Single cells or small cell groups of infected cultures were subjected to pharmacological and electrophysiological experiments. In concentrations ranging from 1 nM to 100 microM, norepinephrine exerted positive or negative chronotropic effects mediated by alpha-adrenergic receptors. A significant number of infected cells (25%) did not respond to the agonist. Two days after infection the cultures exhibited a higher frequency of spontaneous contractions (20%), paralleled by an increase in firing rate and a decrease in the action potential duration without significant changes in maximum diastolic potential and action potential amplitude. A decrease in alpha-adrenergic receptor-mediated positive chronotropic response to norepinephrine was also observed in 2-day infected cells. Cells made to phagocyte ferritin particles showed an increase in the rate of spontaneous contractions, but no changes in the positive chronotropic responses to norepinephrine. In conclusion, these observations show that during acute infection with T. cruzi, there are alterations in automaticity and in the chronotropic responses to norepinephrine, whose mechanisms are related to the process of parasite endocytosis by the cardiac cells.

The relationship among adiposity, diet, and hormone concentrations in vegetarian and nonvegetarian postmenopausal women

The relationships among anthropometric variables, dietary nutrients, and plasma steroid, polypeptide, and binding-protein hormone concentrations were investigated in 24 Seventh-day Adventist postmenopausal women, 12 vegetarian (SV) and 12 nonvegetarian (SNV). Fasting blood and 7-d dietary intake information were collected. SVs consumed significantly more crude and dietary fiber and fewer saturated fatty acids than did SNVs. The thigh and sum of three skinfold-thickness measurements were significantly greater for SNVs than for SVs. Plasma concentrations of estradiol-17 beta were significantly lower in SVs than in SNVs. Significant relationships were observed for the combined groups (SV and SNV) between estradiol-17 beta and triceps and suprailiac skinfold thickness and body fat. Plasma concentrations of estradiol-17 beta of the combined groups revealed a significant negative relationship between their crude and dietary fiber intakes. Further study delineating the effects of adiposity and dietary nutrients on basal concentrations of sex hormones is warranted.

Dietary status of Seventh-Day Adventist vegetarian and non-vegetarian elderly women

The purpose of this study was to investigate nutrient intakes of Seventh-Day Adventist elderly women who were similar in many demographic and life-style factors except for choice of diet. Twenty-three vegetarian and 14 non-vegetarian elderly women (mean +/- standard error ages 72.2 +/- 1.3 and 71.1 +/- 1.4 years, respectively) were recruited on the basis of several selection criteria, including race, religion, education, geographic area, Quetelet index, self-reported absence of major chronic disease and use of medications, and physical activity. Average years +/- SE of adherence to dietary regimens were 47.0 +/- 2.9 and 71.2 +/- 1.4 in the vegetarian and non-vegetarian groups, respectively. Results from analysis of 7-day food records showed that vegetarians consumed significantly less cholesterol, saturated fatty acids, and caffeine but more carbohydrate, dietary fiber, magnesium, vitamins E and A, thiamin, pantothenic acid, copper, and manganese than non-vegetarians (p less than .05). On the basis of group means, 67% of the Recommended Dietary Allowance was met for all nutrients except zinc and vitamin D in both groups, and vitamins B-6, folacin, and vitamin E in the non-vegetarians. Compared with non-vegetarians, vegetarians had significantly lower serum glucose (5.18 +/- 0.11 vs. 4.65 +/- 0.09 mmol/L), low-density-lipoprotein cholesterol (4.08 +/- 0.25 vs. 3.34 +/- 0.19 mmol/L), and total cholesterol levels (6.46 +/- 0.27 vs. 5.62 +/- 0.21 mmol/L) (p less than .05). In summary, when healthy elderly vegetarian women were compared with closely matched non-vegetarian peers, the vegetarian diet was associated with improved nutrient intake and associated reductions in blood glucose and lipid levels.

Hematological, anthropometric, and metabolic comparisons between vegetarian and nonvegetarian elderly women

The purpose of this study was to investigate hematological, anthropometric, and metabolic differences in elderly women who were similar in most respects except for choice of diet. Nineteen vegetarian (V) and 12 non-vegetarian (NV) elderly women (mean ages 72.3 +/- 1.4 and 69.5 +/- 1.0 years, respectively) were recruited based on several selection criteria including race, religion, education, Quetelet Index, absence of major chronic disease and use of medications, physical activity, and geographic area. Average years of adherence by V and NV groups to dietary regimens were 46.3 +/- 3.3 and 69.6 +/- 1.0, respectively; Hematological comparisons revealed that the V elderly women had significantly lower glucose (4.60 +/- 0.09 vs 5.13 +/- 0.11 mmol/L), low-density lipoprotein cholesterol (3.14 +/- 0.19 vs 4.09 +/- 0.27 mmol/L) and total cholesterol levels (5.41 +/- 0.20 vs 6.48 +/- 0.29 mmol/L) than the NV elderly women (P less than 0.01) for each. The V elderly women tended to have less body fat and midupper arm muscle area than the NV. No differences between groups were found in a variety of metabolic and electrocardiographic parameters during graded maximal treadmill testing except for lower heart rates in the V women. VO2max was not significantly different between the V and NV elderly women (23.8 +/- 1.5 vs 21.9 +/- 0.8 ml.kg-1.min-1, respectively). In summary, when healthy elderly V women are compared with closely matched NV peers, the vegetarian diet is associated with several benefits, primarily lower blood glucose and lipid levels, but not greater functional capacity.

[Unilateral exophthalmos caused by orbital metastasis from carcinoma of the prostate]

É relatado um caso de exoftalmo ou proptose unilateral direita, causado por metástase orbitária de carcinoma da próstata em paciente negro, na 6.ª década de vida, com evolução de 9 meses. O exame neuro-ocular revelou acentuada diminuição da agudeza visual, perturbação para visão de cores, perda da convergência, diminuição dos reflexos à luz e acomodação e restrição dos movimentos oculares. O paciente apresentava discreta disbasia esquerda por metástase no fêmur. Exames laboratoriais, radiológicos e a biópsia confirmaram a etiologia carcinomatosa da manifestação ocular.