Does silicon attenuate PEG 6000-induced water deficit in germination and growth initial the seedlings corn.

Water stress limits the initial growth and development of maize mass and grain, as well as the physiological process for absorbing the amount of mineral elements. The objective was to evaluate the effect of silicon on germination and growth of corn seedlings submitted to water deficit. The experiment was carried out in the laboratory and the experimental design was completely randomized (factorial 3 × 4), with three concentrations of calcium silicate (0.0; 1.0 and 2.0 mM) and 4 solutions of PEG-6000 to simulate different osmotic potentials (0, 0; -0.3; -0.6; -0.9 MPa). Germination percentage, germination speed index (GSI), mean germination time (MGT), percentage of non-germinated and abnormal germinated, length and dry matter of shoot, root and total seedlings were evaluated. Water deficiency reduced the parameters TG, GSI and MGT. The water deficit reduce the MSPA, MSR and MST with more than 80% reduction in mass from seedlings without deficiency to seedlings with deficiency. For CPA, CR and CT there was a reduction of at least 87%, 70% and 77%, respectively, among seeds without deficiency compared to seeds submitted to deficiency. The use of silicon in corn seeds did not attenuate the stress caused by water deficit simulated by PEG-6000.

Mitigation of the effects of salt stress in cowpea bean through the exogenous aplication of brassinosteroid.

Cowpea (Vigna unguiculata (L.) Walp.) is a legume widely cultivated by small, medium and large producers in several Brazilian regions. However, one of the concerns for the production of cowpea in Brazil in recent years is the low rainfall activity in these regions, which generates the accumulation of salts on the surface. The objective of this work was to evaluate the effects of salt stress on growth parameters and enzyme activity in cowpea plants at different concentrations of brassinosteroids. Experiment was developed in a greenhouse using a completely randomized experimental design in a 3 x 3 factorial scheme. The treatments consisted of three levels of brassinosteroids (0, 3 and 6 µM EBL) and three levels of salt stress (0, 50 and 100 mM NaCl). Growth factors (height, diameter and number of leaves) decreased in the saline condition. With the presence of brassinosteroid the height did not increase, but the number of leaves did, mainly in the saline dosage of 100 mM NaCl. In the variable membrane integrity, brassinosteroid was efficient in both salinity dosages, the same not happening with the relative water content, where the saline condition did not affect the amount of water in the vegetable, with the application of brassino it remained high, decreasing only at dosage 100 mM NaCl. The nitrate reductase enzyme was greatly affected in the root system even with the application of increasing doses of brassino. Therefore, brassinosteroids as a promoter of saline tolerance in cowpea seedlings was positive. The concentration of 3µM of EBL provided the most satisfactory effect in tolerating the deleterious effects of the saline condition. The same cannot be concluded for the concentration of 6µM of EBL that did not promote tolerance to some variables.

Optical micro-knot resonator hydrophone.

We present results of what are believed to be the first underwater acoustic sensor using an optical micro-knot resonator. The mechanism involves straining the micro-fibre loop of the knot via an appropriate encapsulation material. The micro-knot sensor exhibited a spectral full-width half-depth of 37.7pm with a Q-factor of 41100 after deconvolution with the source. The shift in wavelength at 1550nm was observed to be around 67pm RMS when exposed to underwater acoustic excitation at 40Hz demonstrating a normalized sensitivity of -288 dB re µPa(-1), or 5.83 fm/Pa.

Cell culture and animal infection with distinct Trypanosoma cruzi strains expressing red and green fluorescent proteins.

Different strains of Trypanosoma cruzi were transfected with an expression vector that allows the integration of green fluorescent protein (GFP) and red fluorescent protein (RFP) genes into the beta-tubulin locus by homologous recombination. The sites of integration of the GFP and RFP markers were determined by pulse-field gel electrophoresis and Southern blot analyses. Cloned cell lines selected from transfected epimastigote populations maintained high levels of fluorescent protein expression even after 6 months of in vitro culture of epimastigotes in the absence of drug selection. Fluorescent trypomastigotes and amastigotes were observed within Vero cells in culture as well as in hearts and diaphragms of infected mice. The infectivity of the GFP- and RFP-expressing parasites in tissue culture cells was comparable to wild type populations. Furthermore, GFP- and RFP-expressing parasites were able to produce similar levels of parasitemia in mice compared with wild type parasites. Cell cultures infected simultaneously with two cloned cell lines from the same parasite strain, each one expressing a distinct fluorescent marker, showed that at least two different parasites are able to infect the same cell. Double-infected cells were also detected when GFP- and RFP-expressing parasites were derived from strains belonging to two distinct T. cruzi lineages. These results show the usefulness of parasites expressing GFP and RFP for the study of various aspects of T. cruzi infection including the mechanisms of cell invasion, genetic exchange among parasites and the differential tissue distribution in animal models of Chagas disease.

Further genetic characterization of the two Trypanosoma cruzi Berenice strains (Be-62 and Be-78) isolated from the first human case of Chagas disease (Chagas, 1909).

We describe here an extension of a previous genetic characterization of Trypanosoma cruzi strains (Be-62 and Be-78) isolated from the patient Berenice, the first human case of Chagas disease [Chagas, C., 1909. Nova Tripanomíase humana. Estudos sobre morfologia e o ciclo evolutivo do Schizotrypanum cruzi, n. gen., n. sp., agente etiolójico da nova entidade morbida do homem. Mem. Inst. Oswaldo Cruz 1, 159-218]. We wanted to verify the composition of T. cruzi populations originated from these two isolates. In the present work, 22 enzymatic loci (MLEE), nine RAPD primers and 7 microsatellite loci were analyzed. Clones from both strains were also characterized to verify whether these strains are mono or polyclonal. Be-62 and Be-78 strains were different in 3 out of 22 enzymatic systems, in 3 out of 9 RAPD primers tested and in all microsatellite loci investigated. However, our data suggests that both strains are phylogenetically closely related, belonging to genetic group 32 from Tibayrenc and Ayala [Tibayrenc, M., Ayala, F.J., 1988. Isoenzime variability in Trypanosoma cruzi, the agent of Chagas' disease: genetical, taxonomical, and epidemiological significance. Evolution 42, 277-292], equivalent to zymodeme 2 and T. cruzi II major lineage which, in Brazil, comprises parasites from the domestic cycle of the disease. Microsatellite analyses showed differences between the parental strains but suggested that both populations are monoclonal since each strain and their respective clones showed the same amplification products.

Real time PCR strategy for the identification of major lineages of Trypanosoma cruzi directly in chronically infected human tissues.

Two evolutionary lineages, called Trypanosoma cruzi I and II, have been identified in T. cruzi, the etiologic agent of human Chagas disease. Here, we describe a molecular strategy for direct genetic typing of these major groups of T. cruzi directly in human tissues. The protocol is based on heminested PCR amplification of the D7 region of the 24Salpha ribosomal DNA (rDNA), followed by identification of the products using denaturation curves in real time PCR. The repetitive nature of the gene, and the heminested PCR format insured the high sensitivity necessary to detect the presence of the very scarce T. cruzi DNA present in the chronically infected human tissues. There is 80% DNA sequence homology between the two 24Salpha rDNA alleles that define the T. cruzi I and II groups, sufficient to produce different thermal denaturation curves with melting temperature (TM) values of 81.7+/-0.43 and 78.2+/-0.33 degrees C (mean+/-SEM). Using this technical approach, we analysed tissue samples (esophagi, hearts and colon) from 25 different patients with the gastrointestinal or cardiac forms of Chagas disease; in all of them we found only the presence of T cruzi II. Previous epidemiological and immunological findings had already led to the idea that chronic human infections occurring in Brazil and Argentina might be primarily due to T. cruzi II strains, but all the evidence available had been indirect. Our findings provide definitive proof of this hypothesis and will also allow the establishment of which group of T. cruzi is responsible for Chagas disease in other countries.

Some Psychodidae (Diptera) from Atlantic forest in south-eastern Brazil, with descriptions of Trichomyia dolichopogon sp. nov. and Trichomyia riodocensis sp. nov.

The family Psychodidae includes the medically important phlebotomine sand flies and four other subfamilies that have been little studied in the Neotropics. The authors here report the results of a trip to collect psychodids in Parque Estadual do Rio Doce, a national park in Minas Gerais that contains one of the largest surviving areas of Atlantic Forest in Brazil. Collections made by Malaise and CDC light traps as well as from diurnal resting sites included 15 species of Psychodinae and Trichomyiinae, among them Trichomyia dolichopogon sp. nov., T. riodocensis sp. nov. and 13 other species new to science but represented by females only. Twelve species of phlebotomine sand flies (Lutzomyia spp.) were also collected. Collections from an undisturbed area of the park were much richer faunistically than those from an area that was destroyed by fire in 1967 but had since regenerated, suggesting that recovery after environmental disturbances of this type may be prolonged. This pattern was not seen for phlebotomine sand flies, whose greater abundance and species richness in the disturbed section of the park may be related to their dependence on small mammal hosts, known to be more diverse in this type of habitat.

Microleakage in endodontically treated teeth: influence of calcium hydroxide dressing following bleaching.

AIM: The purpose of the present study was to evaluate microleakage of a fourth generation dentine-bonding agent and composite restoration during a walking bleach treatment. METHODOLOGY: Thirty extracted non-carious incisors were selected and conventional root canal treatment was performed. Teeth were randomly divided into 3 groups (n = 10): group A (control), access cavities were restored with a fourth generation dentine-bonding agent, and incrementally restored with composite resin; group B, a paste composed of sodium perborate and hydrogen peroxide was placed into the pulp chamber and sealed with glass ionomer cement for 7 days, teeth were then restored in the same manner as group A; group C, a paste of sodium perborate and hydrogen peroxide was placed in the pulp chamber for 7 days and then after removal of the bleaching mixture, pulp chambers were filled with a calcium hydroxide paste and cavities sealed with glass ionomer for 1 week. The cavities were then restored with bonded restorations as in groups A and B. Teeth were subjected to thermal cycling and immersed in methylene blue for 8 h. Teeth were sectioned from buccal to lingual, through the centre of the restoration, using a diamond disk. Leakage was assessed using a standard scheme, under magnification (x20). Data were submitted to statistical analysis using nonparametric Kruskal-Wallis test. RESULTS: Groups A and C exhibited similar leakage patterns, and both demonstrated less leakage values than group B (P < 0.05). CONCLUSIONS: It was concluded that bleaching with sodium perborate and hydrogen peroxide increases microleakage; short-term use of a calcium hydroxide medicament did not increase microleakage.

Some Psychodidae (Diptera) from Atlantic Forest in South-Eastern Brazil, with descriptions of Trichomyia dolichopogon sp. nov. and Trichomyia riodocensis sp. nov

The family Psychodidae includes the medically important phlebotomine sand flies and four other subfamilies that have been little studied in the Neotropics. The authors here report the results of a trip to collect psychodids in Parque Estadual do Rio Doce, a national park in Minas Gerais that contains one of the largest surviving areas of Atlantic Forest in Brazil. Collections made by Malaise and CDC light traps as well as from diurnal resting sites included 15 species of Psychodinae and Trichomyiinae, among them Trichomyia dolichopogon sp. nov., T. riodocensis sp. nov. and 13 other species new to science but represented by females only. Twelve species of phlebotomine sand flies (Lutzomyia spp.) were also collected. Collections from an undisturbed area of the park were much richer faunistically than those from an area that was destroyed by fire in 1967 but had since regenerated, suggesting that recovery after environmental disturbances of this type may be prolonged. This pattern was not seen for phlebotomine sand flies, whose greater abundance and species richness in the disturbed section of the park may be related to their dependence on small mammal hosts, known to be more diverse in this type of habitat

Iron and its sensitive balance in the cell.

Iron is vital in life because it is an important component of molecules that undergoes redox reactions or transport oxygen. However, the existence of two stable and inter-convertible forms of iron, iron(III) and iron(II), makes possible one electron being transferred to or captured from other species to form radicals. In particular, superoxide and hydroxyl radicals may be formed in these reactions, both with capacity of attacking other molecules. DNA is one important target and a vast literature exists showing that attack of hydroxyl radical to DNA leads to cell death cellular necrosis, apoptosis, mutation and malignant transformation. Therefore, a fine balance must exist at various levels of an organism to maintain iron concentration in a narrow range, above and below which deleterious effects of distinct nature occur. This review will deal with the formation of oxygen reactive species in iron participating reactions, defenses in the organism against these species, the different mechanisms of iron homeostasis and iron deficiency and iron overload related diseases.

Yeast lacking Cu-Zn superoxide dismutase show altered iron homeostasis. Role of oxidative stress in iron metabolism.

Saccharomyces cerevisiae lacking copper-zinc superoxide dismutase (sod1) shows a series of defects, including reduced rates of aerobic growth in synthetic glucose medium and reduced ability to grow by respiration in glycerol-rich medium. In this work, we observed that addition of iron improved the respiratory growth of the sod1 mutant and in glucose medium total intracellular iron content was higher in the sod1 mutant than in wild type cells. Transcription of the high affinity iron transporter gene, FET3, was enhanced in the sod1 mutant, suggesting that iron transport systems were up-regulated. An sod1/fet3 double mutant showed increased sensitivity to oxygen and increased transcription of FET4, an alternative, low affinity, iron transporter. We propose that this increased iron demand in the sod1 mutant may be a reflection of the cells' efforts to reconstitute iron-sulfur cluster-containing enzymes that are continuously inactivated in conditions of excess superoxide.

Charcoal deposits in the esophageal and gastric mucosa.

We report the case of a 75-yr-old woman referred for gastrointestinal endoscopy to investigate severe iron deficiency anemia. Black linear lesions were observed in the distal esophagus and stomach. Biopsies revealed aggregates of coarse black foreign material, which was later identified as charcoal. The patient's previous medical history included an antidepressant overdose 5 yr before the current admission. The patient had a gastric lavage, using a large bore orogastric tube, followed by the administration of activated charcoal. The patient had no other history of charcoal ingestion. We propose that the charcoal became entrapped in mucosal tears caused by the traumatic intubation 5 yr previously, causing the incidental mucosal tattooing seen at endoscopy.

Brain SPECT in dementia. A clinical-scintigraphic correlation.

The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7%) and statistically similar specificity (63.8 and 81.8%, respectively). The specificity of SPECT in diagnosing Alzheimer's disease (100%) was statistically superior to CT (69%). However, both methods showed similar sensitivity in detecting Alzheimer's disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimer's disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.

[Urinary tract infections. The causative agents and their sensitivities to chemotherapeutic drugs]. / Infecções do tracto urinário. Agentes e sensibilidades aos quimioterápicos.

A retrospective study was made of the requests for bacteriological examination of urine samples by the different clinical departments of Vila Nova de Famalicão District Hospital, between July/89-June/90 and July/91-June/92. We were interested in assessing the spectrum of occurring micro-organisms in urinary tract infections, their antibiotic susceptibility, especially to those more frequently used in clinical practice in this institution and their evolution in time. In conclusion, the prevalence of isolated pathogens was quite similar to the spectrum published by other authors for a hospital population. No significant variation was found in the bacterial population between the two periods analysed, if we exclude the great increase in coagulase-negative staphylococci. In terms of benefits/costs/resistance, we concluded that the best antibiotic for the beginning of therapy in this Hospital is cotrimoxazole. Good choices were also quinolones, third-generation cephalosporins or aminoglycosides, but with the disadvantages of greater cost for the first two and toxicity for the last.

[The transjugular intrahepatic portosystemic shunt]. / Shunt porto-sistémico intra-hepático transjugular.

The case of a 66-year-old woman with several episodes of hemorrhage by esophageal varices and ascites due to portal hypertension is presented. Despite 4 sessions of endoscopic sclerotherapy bleeding recurred. A transjugular intrahepatic portosystemic shunt was performed. In the 10 months following the intervention, there was no further hemorrhage, the ascites disappeared and the shunt is open.

Tratamento dos angiomas do labio / Treatment of lip angiomas

Foram estudados 25 pacientes portadores de angiomas de labio, sendo 17 maduros (15 venosos, 2 complexos) e oito imaturos (7 tuberosos, 1 strawberry). Existem varios tipos de tratamento propostos pela literatura. Dentre os varios metodos, os autores, apos dez anos de experiencia, optaram preferencialmente por cirurgia, cirurgia mais embolizacao e corticoide sistemico. O uso de corticoide local e de agentes esclerosantes foram utilizados apenas como coadjuvantes da cirurgia. A cirurgia, realizada em uma ou mais etapas, se mostrou alternativa segura e eficiente para angiomas maduros, com excecao dos complexos, imaturos com complicacoes e imaturos que nao incluiram ate os cinco anos de idade.

[Treatment of lip angiomas]. / Tratamento dos angiomas do lábio.

The experience with the treatment of 25 patients with angiomas of the lips is presented. Among the several methods of treatment indicated in the literature, the authors have experimented with surgery, surgery and embolization, and systemic corticotherapy. Local application of corticosteroids and sclerosing agents were used just as a complementary therapy to the surgery. Surgery performed in one or more stages when necessary, were considered a safe and reliable method for treatment of mature venous angiomas, as well as for immature ones with no involution after a period of five years.

Embolization to reverse severe recurrent hepatic encephalopathy.

Five patients with porto-systemic shunts, four spontaneous and one surgically created, presenting severe recurrent hepatic encephalopathy rebel to clinical treatment were angiographically examined. A spontaneous splenic-renal veins shunt was observed in four cases and a mesocaval shunt was identified in the remaining patient. Two thirds embolization of the spleen was able to control hepatic encephalopathy in two patients. Percutaneous transhepatic portography and selective embolization of the shunt was performed in two other patients with good results. Percutaneous transcaval embolization of the mesocaval shunt succeeded to control hepatic encephalopathy in the remaining patient. Splenic embolization is able to control hepatic encephalopathy in patients with splenomegaly and spontaneous porto-systemic shunt. Direct embolization of the shunt is also able to control hepatic encephalopathy as should be expected.