Renal and antibacterial effects induced by myotoxin I and II isolated from Bothrops jararacussu venom.

Bothrops jararacussu myotoxin I (BthTx-I; Lys 49) and II (BthTX-II; Asp 49) were purified by ion-exchange chromatography and reverse phase HPLC. In this work we used the isolated perfused rat kidney method to evaluate the renal effects of B. jararacussu myotoxins I (Lys49 PLA2) and II (Asp49 PLA2) and their possible blockage by indomethacin. BthTX-I (5 microg/ml) and BthTX-II (5 microg/ml) increased perfusion pressure (PP; ct120=110.28+/-3.70 mmHg; BthTX I=171.28+/-6.30*mmHg; BthTX II=175.50+/-7.20*mmHg), renal vascular resistance (RVR; ct120=5.49+/-0.54 mmHg/ml.g(-1)min(-1); BthTX I=8.62+/-0.37*mmHg/ml g(-1)min(-1); BthTX II=8.9+/-0.36*mmHg/ml g(-1)min(-1)), urinary flow (UF; ct(120)=0.14+/-0.01ml g(-1)min(-1); BthTX I=0.32+/-0.05*ml g(-1)min(-1); BthTX II=0.37+/-0.01*ml g(-1)min(-1)) and glomerular filtration rate (GFR; ct120=0.72+/-0.10 ml g(-1)min(-1); BthTX I=0.85+/-0.13*ml g(-1)min(-1); BthTX II=1.22+/-0.28*ml g(-1)min(-1)). In contrast decreased the percent of sodium tubular transport (%TNa(+); ct(120)=79,76+/-0.56; BthTX I=62.23+/-4.12*; BthTX II=70.96+/-2.93*) and percent of potassium tubular transport (%TK(+);ct120=66.80+/-3.69; BthTX I=55.76+/-5.57*; BthTX II=50.86+/-6.16*). Indomethacin antagonized the vascular, glomerular and tubular effects promoted by BthTX I and it's partially blocked the effects of BthTX II. In this work also evaluated the antibacterial effects of BthTx-I and BthTx-II against Xanthomonas axonopodis. pv. passiflorae (Gram-negative bacteria) and we observed that both PLA2 showed antibacterial activity. Also we observed that proteins Also we observed that proteins chemically modified with 4-bromophenacyl bromide (rho-BPB) decrease significantly the antibacterial effect of both PLA2. In conclusion, BthTx I and BthTX II caused renal alteration and presented activity antimicrobial. The indomethacin was able to antagonize totally the renal effects induced by BthTx I and partially the effects promoted by BthTx II, suggesting involvement of inflammatory mediators in the renal effects caused by myotoxins. In the other hand, other effects could be independently of the enzymatic activity of the BthTX II and the C-terminal domain could be involved in both effects promoted for PLA2.     

Microcystin-LR promote intestinal secretion of water and electrolytes in rats.

We showed previously that exposure to microcystin-LR causes renal toxic effects in isolated perfused rat kidney, and that inflammatory mediators from supernatants of macrophages stimulated by microcystin-LR are involved in this process. The aim of this research was to examine water and electrolytes secretion in vivo, induced by microcystin-LR and supernatant of macrophages stimulated for this toxin (SUP.MphiS + MCLR), using perfused rat ileal segment and ligated intestinal loop models. We found microcystin-LR at 1 microg/ml (0.09 +/- 0.003* vs. control 0.07 +/- 0.001 g of secretion/2 cm of loop; P < 0.05*) and the SUP.MphiS + MCLR after 18 h postinoculation (0.10 +/- 0.003 vs. control 0.03 +/- 0.002 g/cm) caused intestinal secretion. In addition, microcystin-LR caused significant sodium secretion (-2.18 +/- 0.72* vs. control 2.18 +/- 0.50 microEq g(-1) min(-1)), potassium (-0.26 +/- 0.04* vs. control 0.32 +/- 0.03 microEq g(-1) min(-1)), chloride (MCLR = -3.29 +/- 1.93* vs. control 0.88 +/- 1.25 microEq g(-1) min(-1)) and water (-0.012 +/- 0.004* vs. control 0.002 +/- 0.002 ml g(-1) min(-1)). We also demonstrated SUP.MphiS + MCLR to induce intestinal secretion of electrolytes (sodium, potassium, chloride) and water. These findings suggested that microcystin-LR and lamina propria macrophages-derived mediators are able to induce intestinal secretion in vivo, probably via inhibition of protein phosphatase.     

Impact of atomic layer deposited TiO2 on the photocatalytic efficiency of TiO2/w-VA-CNT nanocomposite materials

Titanium oxide (TiO₂) has been widely investigated as a photocatalytic material, and the fact that its performance depends on its crystalline structure motivates further research on the relationship between preparation methods and material properties. In this work, TiO₂ thin films were grown on non-functionalized wave-like patterned vertically aligned carbon nanotubes (w-VA-CNTs) via the atomic layer deposition (ALD) technique. Grazing incidence X-ray diffraction (GIXRD) analysis revealed that the structure of the TiO₂/VA-CNT nanocomposites varied from amorphous to a crystalline phase with increasing deposition temperature, suggesting a “critical deposition temperature” for the anatase crystalline phase formation. On the other hand, scanning transmission electron microscopy (STEM) studies revealed that the non-functionalized carbon nanotubes were conformally and homogeneously coated with TiO₂, forming a nanocomposite while preserving the morphology of the nanotubes. X-ray photoelectron spectroscopy (XPS) provided information about the surface chemistry and stoichiometry of TiO₂. The photodegradation experiments under ultraviolet (UV) light on a model pollutant (Rhodamine B, RhB) revealed that the nanocomposite comprised of anatase crystalline TiO₂ grown at 200 °C (11.2 nm thickness) presented the highest degradation efficiency viz 55% with an illumination time of 240 min. Furthermore, its recyclability was also demonstrated for multiple cycles, showing good recovery and potential for practical applications.

Amorphous or anatase crystalline TiO₂/VA-CNT nanocomposites were grown controlling the synthesis temperature. Photocatalytic degradation of RhB of 55% was achieved after 240 min. The immobilized material remains active after 4 cycles of use.     

Effects of Crotalus durissus collilineatus venom in the isolated rat kidney.

Ophidian accidents caused by the subspecies Crotalus durissus are responsible for high morbity and mortality rates. Acute renal failure is a common complication observed in these accidents. The aim of the present study was to investigate the renal effects promoted by the venom of C. d. collilineatus and its fractions, crotoxin and phospholipase A2. C. d. collilineatus (Cdc; 30 microg mL(-1)), crotoxin (CTX; 10 microg mL(-1)) and phospholipase A2 (PLA2; 10 microg mL(-1)) were tested in isolated rat kidney. The first 30 min of each experiment were used as an internal control and Cdc or its fractions, CTX and PLA2 were added to the system after this period. All experiments lasted 120 min. The venom of Cdc decreased perfusion pressure (PP; control120 = 110.3 +/- 3.69 mmHg; Cdc120 = 96.7+/-8.1 mmHg), renal vascular resistance (RVR; control120 = 6.42+/-0.78 mmHg mL g(-1) min(-1); Cdc120 = 4.8+/-0.56 mmHg/mL g(-1) min(-1)), urinary flow (UF; control120 = 0.19+/-0.03 mL g(-1) min(-1); Cdc120 = 0.12 +/- 0.01 mL g(-1) min(-1)), and glomerular filtration rate (GFR; control120 = 0.79 +/- 0.07 mL g(-1) min(-1); Cdc120 = 0.53 +/- 0.09 mL g(-1) min(-1)), but had no effect on the percent of sodium tubular transport (%TNa+), percent of chloride tubular transport (%TK+) and percent of potassium tubular transport (%TCl-). CTX and PLA2 reduced the GFR, while UF, PP and RVR remained stable during the full 120 min of perfusion. Crotoxin administration also diminished the %TK+ (control120 = 69.94 +/- 6.49; CTX120 = 33.28 +/- 4.78) and %TCl- (control120 = 79.53 +/- 2.67; CTX120 = 64.62 +/- 6.93). PLA2 reduced the %TK+, but exerted no effect on the %TNa+ or on that of TCl-. In conclusion, the C. d. collilineatus venom altered the renal functional parameters evaluated. We suggest that crotoxin and phospholipase A2 were involved in this process, since the renal effects observed would be due to the synergistic action of the components of the venom.     

Hancornia speciosa: indications of gastroprotective, healing and anti-Helicobacter pylori actions

Ethnopharmacological relevance

Mangaba (Hancornia speciosa Gomez) is a medicinal plant frequently cited in ethnopharmacological inventories of the central region of Brazil against gastrointestinal disorders such as diarrhoea, ulcer, gastritis and stomachache.

Aim of the study

The hydroalcoholic extract (HE) and infusion (BI) of Hancornia speciosa bark were investigated for their ability to prevent and heal rodent gastric ulcer.

Materials and methods

The preventive and healing action of both preparations of Hancornia speciosa were evaluated in experimental models in rodents that simulated this disease in human gastric mucosa.

Results

BI did not exert gastroprotective effect, in contrast to HE (500 mg/kg, p.o.) that decreased (p < 0.05) the severity of gastric damage induced by HCl/ethanol (52%), indomethacin/bethanechol (51%), stress (52%) or pylorus ligature experiments (54%). HE increased (p < 0.05) the pH and decreased acid output of gastric juice. This extract promoted increase of mucus amount (3.62 mg/wt. tissue vs. 5.81 mg/wt. tissue), healing action (67%) and displayed anti-Helicobacter pylori effect.

Conclusions

The antiulcer action of Hancornia speciosa resulted in increase of gastric mucus formation and antioxidant properties of polymeric proanthocyanidins present in the bark composition of this medicinal plant.     

The mediator role of unmet needs on quality of life in myeloma patients

Quality of Life Research - The diagnosis of multiple myeloma (MM) has a significant impact on patients. This study analyzed the mediating role of patients’ unmet needs in the relationship...     

Accelerated Aging Ultraviolet of a PET Nonwoven Geotextile and Thermoanalytical Evaluation

Nonwoven geotextiles are geosynthetic products that are highly susceptible to ultraviolet degradation because light can reach a large area of the material due to its fiber arrangement. Even with additives, which delay the degradation process, material decomposition still occurs, and therefore the product’s long-term durability can be affected. In this paper, the mechanical and thermal behavior of a commercial nonwoven polyester geotextile subjected to accelerated ultraviolet aging tests were evaluated. The deterioration was evaluated by comparing the physical properties (mass per unit area, thickness, and tensile strength) and thermal behavior (thermogravimetry—TG, thermomechanical analysis—TMA, and differential scanning calorimetry—DSC) before and after exposure times of 500 h and 1000 h. The results showed that the ultraviolet aging tests induced some damage in the polyester fibers, leading to the deterioration of their tensile strength. For 1000 h of exposure, in which the reduction was larger, scanning electron microscopy (SEM) found some superficial disruption of the fibers, indicative of damage. TG and DSC could not capture the effects of UV radiation on polymer degradation, unlike TMA. This latter technique was effective in showing the differences between specimens before and after UV exposure.     

Nanocomposites based on the graphene family for food packaging: historical perspective,preparation methods,and properties

Nanotechnology experienced a great technological advance after the discovery of the graphene family (graphene – Gr, graphene oxide – GO, and reduced graphene oxide-rGO). Based on the excellent properties of these materials, it is possible to develop novel polymeric nanocomposites for several applications in our daily routine. One of the most prominent applications is for food packaging, offering nanocomposites with improved thermal, mechanical, anti-microbial, and barrier properties against gas and water vapor. This paper reviewed food packaging from its inception to the present day, with the development of more resistant and intelligent packaging. Herein, the most common combinations of polymeric matrices (derived from non-renewable and renewable sources) with Gr, GO, and rGO and their typical preparation methods are presented. Besides, the interactions present in these nanocomposites will be discussed in detail, and their final properties will be thoroughly analyzed as a function of the preparation technique and graphene family-matrix combinations.

Food packaging based on nanotechnology of polymeric nanocomposites of graphene and graphene oxide results in packaging with better thermal, mechanical, antimicrobial, electrical packaging, moisture barrier and gas properties.