Gamma Irradiation-Assisted Synthesis of Cellulose Nanocrystal-Reinforced Gelatin Hydrogels

Herein, we describe the use of gamma irradiation to prepare hydrogels comprising α-cellulose and cellulose nanocrystal (CNC)-reinforced gelatin in the absence of crosslinking agents. In this study, cellulose was extracted from rice husks by an alkali and bleaching treatment followed by acid hydrolysis to produce CNC. A semi-interpenetrating network (semi-IPN) of hydrogels was developed by the miscibility between gelatin and cellulosic materials. Compared to those prepared from α-cellulose, hydrogels prepared by dispersion of CNCs exhibited remarkably enhanced stiffness and swelling properties, which was ascribed to the uniform distribution of CNCs and their increased crystallinity. Improved pore structure, arrangement, and rigidity of CNC-reinforced gelatin hydrogels, which induced the swelling mechanism resulting in higher and faster water uptake was observed with a scanning electron microscope (SEM), compared to cellulose-reinforced gelatin hydrogels. Moreover, in vitro drug profiling demonstrated that CNC/gelatin hydrogels exhibit good drug loading/release behavior and are thus suitable for use in drug-delivery applications

Pharmacological studies on hypotensive and spasmolytic activities of pure compounds from Moringa oleifera

Bioassay directed fractionation of an ethanolic extract of Moringa oleifera (MO) leaves resulted in the isolation of four pure compounds, niazinin A (1), niazinin B (2), niazimicin (3) and niaziminin A + B (4 + 5). Intravenous administration of either one of the compounds (1–10 mg/kg) produced hypotensive and bradycardiac effects in anaesthetized rats. Pretreatment of the animals with atropine (1 mg/kg) completely abolished the hypotensive and bradycardiac effects of acetylcholine (ACh), whereas cardiovascular responses to the test compounds remained unaltered, ruling out the possible involvement of muscarinic receptor activation. In isolated guinea-pig atria all the compounds (50–150 &#956;g/mL) produced negative inotropic and chronotropic effects. Each compound inhibited K<SUP>+</SUP> -induced contractions in rabbit aorta as well as ileal contractions induced by ACh or histamine at similar concentrations. Spontaneous contractions of rat uterus were also inhibited equally by all compounds. These data indicate that the direct depressant action of these compounds exhibited on all the isolated preparations tested is probably responsible for its hypotensive and bradycardiac effects observed in vivo. Moreover, spasmolytic activity exhibited by the constituents of the plant provides a scientific basis for the traditional uses of the plant in gastrointestinal motility disorders

Vitamin A status of children in the urban slums of Karachi, Pakistan, assessed by clinical, dietary, and biochemical methods

We assessed the vitamin A status of 532 children with an age range of 6–60 months who were living in slum areas of Karachi, Pakistan, using three methodologies; clinical eye examination, dietary vitamin A intake, and serum retinol level. No definite clinical signs of xerophthalmia were observed in any of these children. The mean ± SD vitamin A intake estimated from a food frequency questionnaire for the group with inadequate (low and deficient) serum retinol levels (\u3c 20 µg/dl) was 362 ± 332 retinol equivalents (RE) compared with 431 ± 332) RE in the group with adequate serum levels (P \u3c 0.005). Deficient serum retinol levels (\u3c 10 µg/dl) were present in 12 children (2%); two of these had a healed corneal scar. Low serum retinol levels (10–19 µg/dl) were present in 46%, while 51% children had adequate levels (≥ 20 µg/dl). The mean ± SD serum retinol level for the inadequate (\u3c 20 µg/dl) and adequate groups were 15.3 ± 2.8 and 26.6 ± 6.7 µg/dl, respectively. These results suggest that a significant number of children in these communities have low vitamin A levels and thus may constitute an at risk group. These results also suggest that the dietary intake method may be a simple and inexpensive screening tool for assessment of vitamin A status in communities