Gamma-ray shielding characteristics of flexible silicone tungsten composites.

Silicone being a hybrid elastomer is well known for its excellent thermal and mechanical properties, chemical resistance, compatibility with organic and inorganic fillers, nontoxicity, and flexibility. As the reported literature on silicone tungsten composite is rare, thus, a complete possible spectrum of silicone tungsten composites series with tungsten loading of 0-88.1 %wt has been fabricated by RTV method and studied as a flexible gamma shielding material. Flexible silicone/tungsten composite formulations containing different weight percentages of tungsten powder (0, 30.1, 47.8, 59.8, 68.1, and 88.1 wt %) were developed by the room-temperature vulcanization route. Two lead collimators with diameters of 0.6 cm were used to make a narrow beam geometry for gamma rays emitted from a137Cs (gamma-ray energy of 662 keV) point source. Uncollided flux was measured with a NaI(Tl) scintillation detector enclosed in lead shielding to reduce the background radiation level. The measured mass attenuation coefficient for our composites with 88.1 wt % tungsten was 0.1035 cm2/g, which is nearly 3.5% higher than that of commercially available silicone/tungsten composites named T-Flex (nearly 0.095 cm2/g) containing the same tungsten loading. Similarly, superior half value layers (HVL) of our composites with 88.1 % wt loading of tungsten i.e 1.01 cm versus 1.27 cm for the reported T-Flex counterpart with additional advantage of insitu fabrication on complex geometries. It was also found that the effectiveness of gamma-ray shielding increases with increase in density of the composites, which is due to the increase in the weight percent of tungsten powder. Our material will have applications as shielding material for both mobile and stationary radiation sources and it can also be used as fabrication material for gloves, safety shoes, coats, etc. to protect workers in a radiation environment.

Anti-arthritis activity of roots of Hemidesmus indicus R.Br. (Anantmul) in rats.

OBJECTIVE: To investigate the protective effects of hydroalcoholic and its fractions from roots of Hemidesmus indicus on arthritis in in vitro models of rodents. METHODS: Preliminary phytochemical analysis and thin-layer chromoatography were performed to analyze constituents of hydroalcoholic extract and its three fraction namely ethyl acetate fraction, chloroform fraction and residual fraction of root of Hemidesmus indicus. Arthritis rats models were established by Complete Freund's Adjuvant. The parameters including paw edema, body weight, arthritic index, erythrocyte sedimentation rate, serum rheumatoid factor, serum C-reactive protein, serum nitrite level, and histopathology of synovial joints were observed. Methotrexate was taken as positive control. RESULTS: Rats treated with hydroalcoholic extract (450 mg/kg, p.o.), ethyl acetate (75 mg/kg, p.o.), chloroform (60 mg/kg, p.o) and residual fractions (270 mg/kg, p.o.), showed significant decrease in physical and biochemical parameters compared with arthritic model rats. Hydroalcoholic extract and its ethyl acetate fraction of Hemidesmus indicus showed significantly higher anti-arthritic activity than chloroform and residual fraction. Histopathological analysis demonstrated that both of hydroalcoholic extract and its ethyl acetate fraction had comparable anti-arthritic activity with methotrexates. CONCLUSIONS: The present study suggests that Hemidesmus indicus has protective activity against arthritis and the activity might be attributed to presence of terpenoid in hydroalcoholic extract, as well as in ethyl acetate fraction.

Hepatoprotective activity of Hemidesmus indicus R. br. in rats.

Treatment of rats with paracetamol and CCl4 produced a significant increase in the levels of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP), total and direct bilirubin. Rats pretreated with methanolic extract of roots of H. indicus (100-500 mg/kg body weight, po) exhibited rise in the levels of these enzymes but it was significantly less as compared to those treated with paracetamol or CCl4 alone. The results of methanolic extract of H. indicus were comparable with the standard hepatoprotective agent silymarin (100 mg/kg). Maximum hepatoprotective effect was found to be at the dose of 250 mg/kg body weight in case of CCl4 induced hepatic damage while 500 mg/kg body weight in case of paracetamol induced hepatic damage. The results suggest that methanolic extract of H. indicus roots possesses a potential antihepatotoxic activity.

Oculohypotensive effect of angiotensin-converting enzyme inhibitors in acute and chronic models of glaucoma.

We have studied the effects of various angiotensin-converting enzyme (ACE) inhibitors on intraocular pressure (IOP) of rabbits with experimentally induced ocular hypertension and their mechanism of action. Acute ocular hypertension was induced by infusion of 5% glucose (15 ml/kg) through marginal ear vein, whereas chronic glaucoma was induced by injection of alpha-chymotrypsin into the posterior chamber of the eye. IOP was measured by tonometer. All ACE inhibitors were instilled topically in the eye in a sterile solution. The effect of ACE inhibitors also was studied on serum cholinesterase (true and pseudo) and the enzyme ACE in vitro. Enalaprilat, ramiprilat, and fosinopril produced a time-dependent decrease of IOP in both acute and chronic models of ocular hypertension in rabbits. The decrease in IOP was observed for >4 h, and the extent of decrease was comparable to that with both pilocarpine and betaxolol. Prodrugs enalapril and ramipril failed to produced any change in IOP. Losartan also produced a significant decrease in IOP in the chronic model of ocular hypertension in rabbits. All the three ACE inhibitors were found to inhibit ACE activity in aqueous humor. The enzyme cholinesterase was found to be inhibited by enalaprilat, ramiprilat, and fosinopril. However, atropine did not alter the IOP-lowering effect of enalaprilat in rabbits. Indomethacin pretreatment produced slight but significant inhibition of the IOP-lowering effect of enalaprilat in rabbits. Our data suggest that ACE inhibitors enalaprilat, ramiprilat, and fosinopril produce a significant ocular hypotensive effect in acute and chronic models of ocular hypertension in rabbits. Inhibition of ACE in aqueous humor, and in ocular tissues, resulting in reduced angiotensin II formation, could be one of the major mechanisms responsible for the IOP reduction by ACE inhibitors in rabbits.

Adult intrahepatic solitary choledochal cyst.

A 20-year-old woman presented with dull ache in the abdomen. Ultrasonography and CT scan showed a solitary liver cyst. Roux-en-Y cystojejunostomy was done since there was bile in the cyst. Histology of the cyst wall revealed it to be a choledochal cyst. Solitary intrahepatic choledochal cyst and presentation in adult life are rare.

Prognostic significance of tumor angiogenesis in advanced breast carcinoma: an Indian experience.

Angiogenesis is essential for tumor growth and metastasis. In the present study we investigated the prognostic significance of microvessels (MV) density using immunohisto-localization of factor VIII antigen in 51 breast cancer patients. We counted microvessels per 200x field in the most active areas of neovascularization by staining factor VIII related antigen and graded MV density and correlated with stage, LN involvement and histologic grade. Patients who subsequently developed metastases had significantly high MV counts than patients without metastatic disease (p < 0.001). Patients who subsequently died of the disease had significantly high mean microvessels counts than patients who remained alive at the end of 5 years (p < 0.001). As density of factor VIII antigen staining increased the survival decreased (p < 0.001). All the patients having > 25 MV per 200x field had tumor recurrence faster as compared with patients having < 25 MV (p < 0.02). Thus, the MV count correlates with the prediction for metastasis and poor survival. Such an indicator would be useful in selection of a subgroup of patients with breast cancer who are at high risk for having occult metastasis at presentation and subsequently would benefit from aggressive therapy.