Effect of exposure to silica in inducing autoimmune hepatitis: an experimental animal-controlled study.

OBJECTIVE: The aim of this experimental study is to investigate the effect of subcutaneous and oral sodium silicate in inducing the autoimmune hepatitis. MATERIALS AND METHODS: Twelve Brown Norway rats were studied, six rats were challenged with Sodium Silicate and the rest were challenged with normal saline as a control group. At 14th week post-sodium silicate or normal saline exposure, the rats were sacrificed. Histopathological studies were conducted in six positive autoantibodies responding silicate group rats and then compared with an equal number of negative autoantibodies responding control rats. RESULTS: The liver findings from sodium silicate group of animals showed a histopathological reaction in 3/6 (50%) compared with 0/6 of the corresponding control saline group (p = 0.09). However, the absolute differences in the percentage between the two groups was 50%, the subcutaneous sodium silicate sub-group showed hepatic tissue response close to being statistically significant level (p = 0.05). CONCLUSIONS: After correlating the results with autoantibodies including serum antinuclear antibodies and anti ribo-nucleoprotein response of the same rats, it is concluded that sodium silicate play a role in inducing the autoimmune hepatitis in a genetically susceptible rat model.

Determination of N-chloramines in As-samra chlorinated wastewater and their effect on the disinfection process.

Chlorine is the most widely used disinfectant of wastewater due to its capacity to inactivate most pathogenic microorganisms quickly. However, chlorine reacts with natural organic compounds present in wastewater to produce some undesirable organic byproducts. One such class of compounds is the nitrogenous compounds. The reaction between chlorine and compounds containing a nitrogen atom with one or more hydrogen atoms attached to it will form chloramines which have lower disinfection efficiency. Eighty percent of the wastewater generated in Jordan is treated at the Khirbet As-Samra wastewater treatment plant for eventual use in agriculture. In this study efficiency of chlorination was studied by collecting samples from the effluent of the treatment plant. The yield concentration of N-chloramines upon chlorination was determined. Efficiency of disinfection process as a function of contact time, concentration of chlorine dosage, concentration of nitrogenous compound and pH were studied. In this study, it has been found that at a chlorine dosage of 15 mg/L and contact time of 15 min, the percentage total coliform kill in As-samra wastewater sample was 100%. After addition of histidine, glycine and phenylalanine (15 mg/L in each case) to the wastewater sample, the percentage of total coliform kill dropped to 58, 78 and 79% respectively. When chlorine dosage was increased to 24 mg/L the percentage total coliform kill reached 96, 99 and 100% in wastewater samples treated with 5 mg/L histidine, glycine and phenylalanine, respectively. The percentage total coliform kill dropped to zero in wastewater samples treated with histidine, glycine and phenylalanine at a concentration of 30 mg/L each. This work supports the theory that amino acids and ammonia preferentially react with chlorine to form N-chloramine which significantly reduces the disinfection efficiency of the chlorination process.

Abnormalities of T cell subsets in Behcet disease.

T cells and T cell subsets were studied in the peripheral blood of 18 patients with Behcet disease (8 active and 10 inactive) and 20 healthy controls. When the active disease group was compared with the inactive disease group and the control group, there was a significant increase (85.7% versus 71.3% and 69%) in the mean percentage of T cells for the active disease group. The mean percentage of CD4 cells for the active disease group (36%) was also significantly decreased from the mean value of the inactive disease group (36%) was also significantly decreased from the mean value of the inactive disease group (41%) and the controls (40%). There was a concomintant significant increase of CD8 cells of the group with active disease (43%) over the mean value for the group of inactive disease (32%) and controls (33%). These results indicated that there were alterations of T cells and T cell subsets in Behcet disease. In contrast to other studies, we found that the T cell number increased with disease activity in our patients; but the significance of single measurement of T cell number increased with disease activity in our patients; but the significance of single measurement of T cell subsets in a course of chronic disease must be taken into consideration.