Vascular effects and electrolyte homeostasis of the natriuretic peptide isolated from Crotalus oreganus abyssus (North American Grand Canyon rattlesnake) venom.

Crotalus oreganus abyssus is a rattlesnake that is usually found in the Grand Canyon, United States of America. Knowledge regarding the composition of C. o. abyssus venom is scarce. New natriuretic peptides (NPs) have been isolated and characterized from the venoms of members of the Crotalinae family. The NP family comprises three members, ANP (atrial natriuretic peptide), BNP (b-type natriuretic peptide) and CNP (c-type natriuretic peptide), and has an important role in blood pressure regulation and electrolyte homeostasis. The aim of the present study was to characterize a novel natriuretic-like peptide (Coa_NP2), isolated from C. o. abyssus venom. The Coa_NP2 presents an average molecular mass of 3419.88Da (theoretical average molecular mass 3418.94Da, monoisotopic molecular mass 3416.66Da and theoretical PI 7.78) and its amino acid sequence presents the loop region that is characteristic of natriuretic peptides. The peptide has 32 amino acids and its complete sequence is SYGISSGCFGLKLDRIGTMSGLGCWRLLQDSP. Coa_NP2 is a natriuretic peptide of the ANP/BNP-like family, since the carboxyterminal region of CNP has its own NP domain. We demonstrate, herein, that Coa_NP2 produces a dose-dependent decrease in mean arterial pressure in rats, followed by significant increases in concentrations of markers of nitric oxide formation measured in the plasma and vasorelaxation in a thoracic aortic ring bath. The structural and biological aspects confirm Coa_NP2 as a new natriuretic peptide, isolated from snake venom.

Molecular modeling and inhibition of phospholipase A2 by polyhydroxy phenolic compounds.

Phospholipases A(2) are enzymes responsible for the hydrolysis of membrane phospholipids that release arachidonic acid, which serves as substrate for pro-inflammatory mediators, such as prostaglandins and leucotriens. The design of specific inhibitors for PLA(2) might help in the development of new anti-inflammatory drugs. Polyhydroxy phenolic compounds, such as flavonoids, vitamin E, rosmarinic acid and aristolochic acid, are able to inhibit PLA(2) from different sources. Herein, we have studied the kinetic behavior and the capacity of inhibiting edema formation induced by PLA(2) of five different polyhydroxy phenolic compounds (two phenolic derivatives and three acetophenone hydroxylated derivatives) extracted from the venom of Crotalus adamanteus. The results showed that compounds 1,3-dihydroxy benzene, 1,3,5-trihydroxy benzene and 2,4,6-trihydroxy acetophenone were the most efficient in the inhibition of the enzymatic activity and edema induction by PLA(2). It was also verified that the number of hydroxyls in each molecule is not a limiting factor for the inhibition capacity of these compounds. Molecular modeling studies indicated that the most active compounds are linked to the amino acid Asp 49 and that they destabilize the coordination of the calcium atom, which is essential to the catalytic activity. The study of potential surfaces showed that there are conditions in which the potential values must be adequate for enzyme complex formation with polyhydroxy phenolic compounds. When the potential over the hydroxyl surfaces is very high, formation of stable complexes does not occur and the enzyme does not act intensely. These results might be helpful in the design of a drug that specifically inhibits PLA(2).

Isolation and characterization of a lectin from Annona muricata seeds.

A lectin with a high affinity for glucose/mannose was isolated from Annona muricata seeds (Annonaceae) by gel filtration chromatography on Sephacryl S-200, ion exchange chromatography on a DEAE SP-5 PW column, and molecular exclusion on a Protein Pak Glass 300 SW column. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (PAGE) yielded two protein bands of approximately 14 kDa and 22 kDa. However, only one band was seen in native PAGE. The Mr of the lectin estimated by fast-performance liquid chromatography-gel filtration on Superdex 75 was 22 kDa. The lectin was a glycoprotein with 8% carbohydrate (neutral sugar) and required divalent metal cations (Ca2+, Mg2+, and Mn2+) for full activity. Amino acid analysis revealed a large content of Glx, Gly, Phe, and Lys. The lectin agglutinated dog, chicken, horse, goose, and human erythrocytes and inhibited the growth of the fungi Fusarium oxysporum, Fusarium solani, and Colletotrichum musae.

Surgical removal of subfoveal choroidal neovascularization without removal of posterior hyaloid: a consecutive series in younger patients.

PURPOSE: Subfoveal choroidal neovascularization (CNV) remains a common and important cause of visual loss. Previous studies have suggested that submacular surgery may improve or maintain visual acuity, particularly in younger patients. The majority of reported cases included removal of the posterior hyaloid during vitrectomy. The authors present a consecutive series of patients age 55 or younger with subfoveal CNV removal without posterior hyaloid removal. METHODS: Seventeen patients without age-related macular degeneration (ARMD), with subfoveal CNV from choroiditis, presumed ocular histoplasmosis syndrome, myopia, or idiopathic causes, underwent a small retinotomy technique to extract the membranes after vitrectomy without posterior hyaloid removal. RESULTS: Median improvement in visual acuity was from 20/320 to 20/50. Eleven patients (65%) experienced an improvement of three or more lines of Snellen acuity (average 7.5), 4 (23%) were within two lines of preoperative acuity, and 2 (12%) had decreased acuity, with an average follow-up of 12 months (range 3-31). Choroidal neovascularization recurred in six patients (35%). Postoperative retinal detachment, epiretinal proliferation, or macular hole did not occur. CONCLUSIONS: In this series of younger patients with subfoveal CNV not from ARMD, visual acuity was improved in the majority after submacular membrane removal. Omission of removal of the posterior hyaloid did not adversely affect outcome.

Esomeprazole once daily for 6 months is effective therapy for maintaining healed erosive esophagitis and for controlling gastroesophageal reflux disease symptoms: a randomized, double-blind, placebo-controlled study of efficacy and safety.

OBJECTIVE: Esomeprazole, the S-isomer of omeprazole, achieves a significantly greater healing rate and symptom resolution of erosive esophagitis than that achieved by omeprazole. The objective of this study is to assess the efficacy of the new proton pump inhibitor esomeprazole in preventing relapse over a prolonged period in patients with healed erosive esophagitis. METHODS: A total of 318 gastroesophageal reflux patients whose erosive esophagitis was healed in a comparative study of esomeprazole 40 mg, 20 mg, or omeprazole 20 mg, were randomized to maintenance therapy with once daily esomeprazole 40 mg, 20 mg, or 10 mg, or placebo in a U.S., double-blind multicenter trial. RESULTS: After 6 months, healing was maintained (cumulative life table rates) in 93.6% (95% CI 87.4-99.7) of patients treated with esomeprazole 40 mg, 93.2% (95% CI 87.4-99.0) treated with esomeprazole 20 mg, and 57.1% (95% CI 45.2-69) treated with esomeprazole 10 mg; p < 0.001 vs placebo (29.1%; 95% CI 17.7-40.3). Of patients relapsing, mean time to first recurrence of esophagitis increased with dose, from 34 days (placebo) to 78 days (10 mg), 115 days (20 mg), and 163 days (40 mg). Patients treated with esomeprazole had less frequent and less severe heartburn than those treated with placebo. At month 6, more than 70% of patients being treated with esomeprazole remained symptom-free. CONCLUSIONS: Esomeprazole is effective and well tolerated in the maintenance of a healing erosive esophagitis. Esomeprazole 40 mg and 20 mg maintain healing in over 90% of patients while providing effective control of heartburn symptoms.

Successful erbium: YAG laser-induced chorioretinal venous anastomosis for the management of ischemic central retinal vein occlusion. A report of two cases.

BACKGROUND: Central retinal vein occlusion (CRVO) is a disorder with potentially blinding complications, particularly when associated with retinal ischemia. There is no reliable treatment for ischemic CRVO. METHODS: We developed a new approach for ischemic cases of CRVO consisting of vitrectomy, posterior hyaloid detachment, and four erbium:YAG laser-induced chorioretinal anastomoses, one in each quadrant. RESULTS: We report two cases of ischemic CRVO treated with this approach, with initial visual acuity of count fingers at 30 cm and hand movements respectively. After the surgery, there was resolution of hemorrhages and macular edema and visual improvement to 20/400 in the first case and to 20/180 in the second case. In both cases, there was successful creation of chorioretinal anastomoses, and there was no anterior segment neovascularization or other complications related to the surgery. CONCLUSION: This treatment shows promise in the management of the ischemic cases of CRVO, and further evaluation is justified.

Two new SUNCT cases responsive to lamotrigine.

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a rare and debilitating headache form generally unresponsive to treatment. Following a recent report of a SUNCT patient who responded to lamotrigine, we tried this drug in two new SUNCT patients, reported here. In both cases prophylaxis was successful, suggesting lamotrigine might be the first effective treatment for this rare and debilitating headache syndrome.