Biosorptive behaviour of rice hulls for Cs-134 from aqueous solutions: a radiotracer study.

Removal behaviour of rice hulls was assessed for the removal of Cs-134 from aqueous solutions. Results obtained from batch-type experiments revealed that relatively low uptake of Cs(I) was favoured with increasing the sorptive concentration (from 1 x 10(-8) to 1 x 10(-2) molL(-1)), temperature (298-328), and pH (2.40-10.20). The concentration dependence data fitted well for Freundlich adsorption isotherm. Thermodynamic parameters revealed that the uptake process was endothermic and proceeded via 'ion exchange' along with 'surface complexation'. Moreover, the adsorbed species were not to be desorbed into the bulk concentration even at elevated temperatures, i.e., up to 328 K hence forming a stable adsorption phase. Further, the radiation stability of the rice hulls samples was also assessed by exposing it towards 300 mCi neutron source having the neutron flux of ca. 3.85 x 10(6) ncm(-2)s(-1) associated with nominal gamma-dose of ca. 1.72 Gyh(-1) and indeed it was observed that the rice hulls samples were found to be stable at least for the removal of Cs-134.     

Neuritic leprosy: epidemiology and therapeutic responsiveness.

We studied epidemiology, progression and therapeutic responsiveness in 62 cases of neuritic leprosy. Numbness was the main presenting symptom. Mononeuritis involving the ulnar nerve, followed by the common peroneal nerve was the commonest presentation. The lepromin test was positive in 34 cases while a slit-skin smear was negative in all cases. We treated 20 of these cases with dapsone monotherapy and 5 cases (25%) developed a skin lesion after an average duration of 3 months' treatment. We treated 42 cases with a combination of dapsone and rifampicin, and 3 cases (7%) developed a skin lesion after an average duration of 2-6 months. The subsequent diagnosis in cases developing skin lesions was borderline--lepromatous in 1 case, borderline-tuberculoid in 4 cases, tuberculoid in 2 cases and indeterminate in 1 case.     

Synthesis and anti-HIV activity of 4'-thio-2',3'-dideoxynucleosides.

A series of 2',3'-dideoxy-4'-thionucleoside analogues of purines and pyrimidines, including 4'-thioddI (17), 4'-thioddC (27), and 4'-thioAZT (34), were synthesized and evaluated for their inhibitory activity against human immunodeficiency virus (HIV). A stereospecific synthesis of the 2,3-dideoxy-4-thioribofuranosyl carbohydrate precursor 11 starting with L-glutamic acid is described. 2',3'-Dideoxy-4'-thiocytidine (27) displayed significant, but modest activity in vitro against human immunodeficiency virus.     

Multidrug therapy in hospitalised leprosy cases

Fifty eight cases including 44 paucibacillary and 14 multibacillary leprosy diagnosed at Command Hospital SC Pune were hospitalised for the entire period of multidrug therapy. 76% cases belonged to high endemic states of India. Reactions occurred in 13 cases during treatment, type I in 10 and type II in three. 7 Multibacillary cases experienced reaction. 69% reaction patients developed reaction within two months of starting MDT and all of them were multibacillary. Usually it took 3-6 months for majority (61.5%) of reactions subside completely. In 65.5% paucibacillary patients activity subsided within twelve months, however 70.5% paucibacillary cases took more than six months to exhibit subsidence of activity. In 13 multibacillary cases activity subsided by 18 months though bacteriological negativity was obtained from fourth to twelve months.     

Improving endothelial cell retention for single stage seeding of prosthetic grafts: use of polymer sequences of arginine-glycine-aspartate.

OBJECTIVE: single stage seeding within the timeframe of a typical vascular operation has not been successful. One reason for this is poor cell adherence to the graft lumen once exposed to pulsatile blood flow. In this study we have carried out investigations with the use of two different fibronectin-based peptides, fibronectin-like engineered protein polymer (FEPP) which contains multiple copies of arginine-glycine-aspartate (RGD) and fibronectin adhesion promoting peptide (FAPP) to improve cell adherence. MATERIALS AND METHODS: FAPP and FEPP were coated onto native polyurethane and heparinised polyurethane grafts. The grafts were then seeded for either 1 or 2h with human umbilical vein endothelial cells (HUVEC). After the incubation period the cells were washed off and cell retention was calculated. Cell metabolism was measured using Alamar Blue, and confirmed with scanning electron microscopy (SEM). RESULTS: heparinised grafts coated with FEPP showed the best cell retention after both 1 and 2h seeding (80+/-4% vs 81+/-3%). This graft had no significant difference in cell retention after both times whilst all the other grafts had better cell retention after a 2h seeding. The Alamar blue and SEM results confirmed cell viability and function for all graft types. CONCLUSION: heparinised graft coated with FEPP allows significant cell retention after only 1h of seeding and shows promise for single stage seeding.     

Synthesis and biological activity of 2'-deoxy-4'-thio pyrimidine nucleosides.

2'-Deoxy-4'-thiocytidine (7 beta), 2'-deoxy-4'-thiouridine (9), and 4'-thiothymidine (10) have been synthesized and evaluated for cytotoxicity in vitro. All these compounds were cytotoxic to L1210, H-Ep-2, and CCRF-CEM cell lines. 4'-Thiothymidine was also active against herpes simplex 1 and human cytomegalovirus in cell culture.     

Radiotracer technique in adsorption study: Part XVII. Removal Behaviour of Alkali Metal (K- and Li-) Titanates for Cd(II)

Alkali metal (potassium and lithium) titanates were synthesized and employed for the efficient removal of Cd(II) ions from aqueous solutions using the radiotracer technique. The possible mechanism involved at the solid/solution interface was deduced with the help of various physico–chemical data, i.e. effect of adsorptive concentration temperature and pH. The effect of added cations and H⁺ (HCl/H₂SO₄) in the uptake process was also seen. The radiation stability of these materials in the adsorption process was assessed by employing a 11.1 GBq (Ra–Be) neutron source having an integral neutron flux of 3.85×10⁶ n·cm⁻² s⁻¹ and associated with a nominal γ-dose of ca. 1.72 Gy/h.