Procoagulant activity of Calotropis gigantea latex associated with fibrin(ogen)olytic activity.

The latex of Calotropis gigantea is a rich source of useful components that has medicinal properties and one of the main applications is in controlling bleeding. The crude latex extract contained many proteins, which are highly basic in nature and exhibited strong proteolytic activity. The crude extract hydrolyses casein, human fibrinogen and crude fibrin clot in a dose-dependent manner. The hydrolyzing activity was completely inhibited by IAA indicating they belong to the super family, cysteine proteases. Crude extract hydrolyses Aalpha, Bbeta and gamma subunits of fibrinogen. Among all the subunits the preferential subunit to get hydrolyzed was Aalpha followed by Bbeta and gamma subunit is highly resistant and hydrolyzed at higher protein concentration or over a prolonged incubation time. The crude extract hydrolysis crude fibrin clot strongly compared to trypsin and papain. Pharmacologically the crude extract is hemorrhagic and induces skin hemorrhage at >75 microg and reduces the coagulation time of citrated plasma from 150 to 47 s and promotes blood coagulation. Procoagulation and blood clot hydrolysis are important in wound healing process. This is due to unique cysteine proteases of plant latex and is responsible for the pharmacological actions observed in folk medicine.     

Edema-inducing activity of phospholipase A2 purified from human synovial fluid and inhibition by aristolochic acid

A neutral-active, Ca²⁺-dependent phospholipase A₂ (PLA₂) purified 11,000-fold from human synovial fluid (HSF) induced edema when injected into the mouse foot pad. The edema produced by HSF-PLA₂ was dose-dependent and was positively correlated with the dose-dependent in vitro expression of PLA₂ activity. Maximum edema was achieved within 45 min after the injection and persisted for atleast 6 h. Aristolochic acid [8-methoxy-6-nitrophenanthro(3,4-d)-1,3-dioxole-5-carboxylic acid], a major chemical component derived from various species ofAristolochia plant, produced a dose-dependent inhibition of in vitro phospholipid hydrolysis by HSF-PLA₂, porcine pancreatic PLA₂, snake venom (Naja naja) PLA₂, and PLA₂ isolated from human platelet. The sensitivity of these PLA₂s to inhibition by aristolochic acid varied markedly: HSF-PLA₂>N.naja PLA₂>human platelet PLA₂>porcine pancreatic PLA₂. The inhibition of HSF-PLA₂ by aristolochic acid was independent of substrate concentration (18–144M and Ca²⁺ concentration (0.1–4.0 mM). These observations indicate that inhibition of HSF-PLA₂ by aristolochic acid may result from direct interaction with the enzyme. When aristolochic acid was mixed with HSF-PLA₂ and then injected into the mouse foot pad, edema was inhibited in a dose-dependent manner and was positively correlated with in vitro inhibition of PLA₂ activity. Alkylation of HSF-PLA₂ withp-bromophenacyl bromide concomitantly inhibited both enzyme and edema-inducing activity. These results clearly demonstrate that the neutral-active, Ca²⁺-dependent PLA₂ isolated from human synovial fluid is proinflammatory and that catalytic activity is positively correlated with in vivo proinflammatory effects.     

Synthesis and evaluation of trimethoxyphenyl isoxazolidines as inhibitors of secretory phospholipase A2 with anti-inflammatory activity

A series of trimethoxyphenyl isoxazolidine derivatives, 5a(i-v) and 5b(i-v), bearing different constituents at the 5th position of the isoxazolidine ring were synthesized and evaluated in vitro and in vivo for their inhibitory activity against purified group I and II phospholipase A2 (PLA2) enzymes from snake venom and human inflammatory synovial fluid. Irrespective of modification to the pharmacophore (isoxazolidine ring), they exhibited greater specificity for group II PLA2. The length of alkyl or aryl group at the 5th position, which alters the hydrophobic and aromatic property, was responsible for enhancing the inhibition towards PLA2 enzymes. All of the compounds quench the fluorescent property of the purified PLA2 enzyme, and quenching increases with the increase in length of alkyl or aryl group. The inhibitory effect of compounds appeared to be due to the direct interaction of compounds with the enzyme. Inhibition is substrate-dependent, and the inhibitor likely competes with the substrate for the same binding site of the enzyme. The IC50 value for the most potent interacting inhibitor 5b(v) was 54.8 microM. The most active interacting compounds 5a(v) and 5b(v) from in vitro inhibition of PLA2 activity showed similar potency in in vivo neutralization of PLA2-induced mouse paw edema and hemolytic activity.     

Fungal Purulent Constrictive Pericarditis in a Heart Transplant Patient

Purulent pericarditis caused by Candida species is rare and is associated with very high mortality. Immunosuppressed transplant patients are particularly susceptible to fungal infections. We report a case of Candida purulent constrictive pericarditis in an immunocompromised heart transplant patient who was treated successfully with antifungal agents, surgical drainage, and pericardiectomy.     

Mesenteric fibromatosis with involvement of the gastrointestinal tract.

Primary mesenteric fibromatosis is a rare condition. The aggressive nature of these tumors and the potential for major morbidity secondary to resection makes it a challenging disease for the surgeon. We report a case of mesenteric fibromatosis with involvement of small bowel.     

Cigarette smoke induced oxidative insult in local population of Pokhara.

Objectives: To assess the effect of cigarette smoking on lipid peroxidation induced oxidative stress, antioxidants, uric acid and blood sugar in normal subjects. Methods: The study included 61 normal subjects with regular smoking habit and 57 never-smokers normal subjects matched in respect to socio-economic status, age and BMI. Information regarding smoking habit and other personal details were collected by oral questionnaire. Total antioxidant activity (TAA), reduced glutathione (GSH), alpha-tocopherol (alpha-T), ascorbic acid (AA), uric acid (UA), plasma and urinary thiobarbituric acid reactive substances (TBARS), fasting blood sugar (FBS) and urinary creatinine (Cr) were estimated by standard procedures in both the groups. Ferric Reducing Antioxidant Power (FRAP) procedure is used to estimate TAA which measures total dietary antioxidants. Statistical analysis was done with SPSS version 10. Results: The mean pack years smoked by smokers was 14.4 +/- 15.8. The plasma TBARS level in smokers and never-smokers was 2.6 +/- 0.8 and 2.5 +/- 0.6 micromol/L respectively. The respective figure for urinary TBARS level was 4.6 +/- 2.7 and 3.7 +/- 1.4 micromol/gmCr. Smokers did not show any significant difference from never-smokers with respect to GSH, alpha-T, AA, plasma TBARS and FBS. However, the smokers had significantly lower levels of TAA (p<0.05) and raised level of urinary TBARS (p<0.05) and uric acid (p<0.01) as compared to never-smokers. Conclusion: Our study suggests that smoking induces mild lipid peroxidation but the body is able to compensate for it by removing its adducts. Importantly it also indicates enhanced oxidation of purines which are essential components of both DNA and RNA. Dietary antioxidants are consumed to scavenge free radicals (FR) and other reactive species (RS) in smoke. Female smokers are more prone to oxidative insult than male smokers. In summary RS present in smoke induce mild lipid peroxidation but are not the major contributors of redox imbalance in smoke induced toxicity in the selected subjects. Key words: Tobacco, Smoking, Free radicals, Oxidative stress, Antioxidants.