Effect of arsenic-phosphorus interaction on arsenic-induced oxidative stress in chickpea plants

Arsenic-induced oxidative stress in chickpea was investigated under glasshouse conditions in response to application of arsenic and phosphorus. Three levels of arsenic (0, 30 and 60 mg kg−1) and four levels of P (50, 100, 200, and 400 mg kg−1) were applied to soil-grown plants. Increasing levels of both arsenic and P significantly increased arsenic concentrations in the plants. Shoot growth was reduced with increased arsenic supply regardless of applied P levels. Applied arsenic induced oxidative stress in the plants, and the concentrations of H2O2 and lipid peroxidation were increased. Activity of superoxide dismutase (SOD) and concentrations of non-enzymatic antioxidants decreased in these plants, but activities of catalase (CAT) and ascorbate peroxidase (APX) were significantly increased under arsenic phytotoxicity. Increased supply of P decreased activities of CAT and APX, and decreased concentrations of non-enzymatic antioxidants, but the high-P plants had lowered lipid peroxidation. It can be concluded that P increased uptake of arsenic from the soil, probably by making it more available, but although plant growth was inhibited by arsenic the P may have partially protected the membranes from arsenic-induced oxidative stress

The role of endoscopic ultrasound in the evaluation of rectal cancer

Accurate staging of rectal cancer is essential for selecting patients who can undergo sphincter-preserving surgery. It may also identify patients who could benefit from neoadjuvant therapy. Clinical staging is usually accomplished using a combination of physical examination, CT scanning, MRI and endoscopic ultrasound (EUS). Transrectal EUS is increasingly being used for locoregional staging of rectal cancer. The accuracy of EUS for the T staging of rectal carcinoma ranges from 80-95% compared with CT (65-75%) and MR imaging (75-85%). In comparison to CT, EUS can potentially upstage patients, making them eligible for neoadjuvant treatment. The accuracy to determine metastatic nodal involvement by EUS is approximately 70-75% compared with CT (55-65%) and MR imaging (60-70%). EUS guided FNA may be beneficial in patients who appear to have early T stage disease and suspicious peri-iliac lymphadenopathy to exclude metastatic disease

Outcomes of truncal vascular injuries in children.

BACKGROUND: Pediatric truncal vascular injuries occur infrequently and have a reported mortality rate of 30% to 50%. This report examines the demographics, mechanisms of injury, associated trauma, and outcome of patients presenting for the past 10 years at a single institution with truncal vascular injuries. METHODS: A retrospective review (1997-2006) of a pediatric trauma registry at a single institution was undertaken. RESULTS: Seventy-five truncal vascular injuries occurred in 57 patients (age, 12 +/- 3 years); the injury mechanisms were penetrating in 37%. Concomitant injuries occurred with 76%, 62%, and 43% of abdominal, thoracic, and neck vascular injuries, respectively. Nonvascular complications occurred more frequently in patients with abdominal vascular injuries who were hemodynamically unstable on presentation. All patients with thoracic vascular injuries presenting with hemodynamic instability died. In patients with neck vascular injuries, 1 of 2 patients who were hemodynamically unstable died, compared to 1 of 12 patients who died in those who presented hemodynamically stable. Overall survival was 75%. CONCLUSIONS: Survival and complications of pediatric truncal vascular injury are related to hemodynamic status at the time of presentation. Associated injuries are higher with trauma involving the abdomen

Toxicity of thimerosal on the corneas of adult pigmented rabbits

Thimerosal is a common preservative agent used in cleaning and disinfecting solutions for hard and soft contact lenses. This agent's toxicity is commonly assessed by the Draize test in which drops of thimerosal are applied to the rabbit eye and reaction of the eye evaluated. Thimerosal is known to cause adverse ocular reaction in some contact lens patients but it is not known whether these reactions are chemotoxic or immunologic in origin. The primary aim of the study was to compare the tissue thresholds to the effects of thimerosal when applied as drops and in a soft contact lens. A secondary aim was to establish how hypersensitivity to thimerosal might develop and play a role in clinical situation. Eight adult pigmented rabbits were used in the study. Toxicity threshold of the cornea to thimerosal was measured using various concentration of thimerosal drops and by soaking soft contact lenses in thimerosal of different concentrations. The main result is that the toxicity threshold of the cornea to thimerosal is ten times higher when applied as drops than when applied in a soft contact lens. In addition, local hypersensitivity to thimerosal did not develop after eight weekly of daily application of thimerosal drops to the eyes. These findings support the initial hypothesis that the threshold level for toxicity using thimerosal-soaked contact lenses would be lower than that of thimerosal drops. This probably occurs because the contact lens keeps the thimerosal in contact with the eye longer than following its topical instillation.Optometry, College o

Physico-chemical characterization of Ogun and Sokoto phosphate rocks

There is a need to identify potential phosphate rock sources to supply phosphorus (P) for crop growth and sustain food production. Physico-chemical characteristics of phosphate rocks from two Nigerian deposits were evaluated to determine their suitability for processing or direct application as P fertilizer. Physical properties such as textural forms, hardness, specific gravity, shrinkage, water absorption capacity and firing color were determined. Ogun rock phosphate (ORP) and Sokoto rock phosphate (SRP) were also subjected to chemical and mineralogical analysis. Solubility tests were conducted at two different particle sizes in 2% citric acid. ORP had a higher water absorption capacity and shrinkage than SRP while specific gravity of ORP was lower. Total P2O5 of SRP and ORP were 36.1% and 31% respectively, which is greater than P2O5 content of Morocco rock phosphate. Both ORP and SRP contained carbonate fluorapatite and chlorapatite minerals. Gypsum, calcite and lime were associated with both rock phosphates indicating their liming potential in the soil. ORP was more soluble in water, probably because it has a lower pH (5.0) than SRP (7.8). Higher solubility of SRP in 2% citric acid may be caused by its high carbonate content. Solubility of both rocks in 2% citric acid increased with decreasing particle size. Solubility of both rocks in 2% citric acid was greater than 30% indicating that they are reactive rocks. The agronomic effectiveness of these rocks has been validated in several on farm trials. We recommend these phosphate rocks for production of P fertilizers and direct application in crop production.Keywords: Phosphorus, apatite, crop production, fertilizer, Ogun rock phosphate, Sokoto rock phosphat

Metal (Loid)s in Farmland Soils and Strategies to Reduce Bioavailability

High concentrations of heavy metal (loid)s (HMs) in farmland soils reduces crop yield and contaminates the food chain. Exposure to HMs in the diet results in several adverse health effects such as cancer, reproductive health problems and cardiovascular diseases. Understanding the origin and fractionation of these toxic substances will provide direction for reducing their bioavailability in contaminated farmland soils. HMs are added to farmland soils through activities such as irrigation, organic and inorganic fertilization, pest control, and mining. Weathering of parent material and atmospheric deposition can also increase the levels of HMs in the soil. Fractionation of HM contaminated soils provides information on availability of HMs such as Pb, Cd, As, Cr and Cu to soil biota and plants. Several studies have reported that Pb is mostly associated with Fe and manganese oxides (reducible fraction) while Cd is mostly associated with the most mobile fraction (exchangeable fraction). The application of organic and inorganic soil amendments such as vermiculite, zeolite, composts and crop residue to contaminated farmland soils converts HMs from the plant available fractions to the less mobile fractions. HM resistant microbes can change HMs to a less mobile fraction or less mobile oxidation state. The combination of HM resistant microbes, HM tolerant plants, and soil amendments can be used to reduce mobility of HMs in contaminated farmlands.</p