Structural and pharmacological profile of generic enoxaparins used in Brazil

Generic active pharmaceutical ingredients (APIs) have been commonly used in Brazil, since 1999, but most of them are synthetic and small molecules. Recently, a large number of generic enoxaparins were introduced into the market raising concerns related to product-to-product interchangeability, efficiency, and drug counterfeiting. These drugs are produced from biological sources and their production involves complex procedures and purification processes. The present article evaluates several generic enoxaparins, structurally and pharmacologically, and compares them with the branded products. Structural analysis showed that the generic products are, indeed, quite similar to the branded products, however, this similarity cannot be extended to their pharmacological activities. The results showed that generic products must go through extensive structural, pharmacological, and clinical evaluation in order to assess their quality, efficacy and, ultimately, avoid drug counterfeiting before clinical use. Variation was also observed between the branded products, showing that such drugs must be at constant surveillance.     

Ischemic stroke in the setting of chronic immune thrombocytopenia in an elderly patient--a therapeutic dilemma

Chronic immune thrombocytopenia (ITP) carries a poor prognosis in the elderly patients. Increasing evidence proposes that a subgroup of patients with chronic ITP may be more susceptible to ischemic stroke. An 84-year-old Caucasian man with multiple ischemic stroke risk factors presented with acute onset of slurred speech, confusion, and unsteady gait. Physical examination and neurologic imaging were consistent with a new left thalamic infarct. Platelet counts ranged between 40 000 × 10(9)/L and 65 000 × 10(9) /L. Antiplatelet therapy for his newly acquired stroke was not initiated considering his low platelet counts and for mildly symptomatic thrombocytopenia, and the patient was discharged home. Both hematologic and neurologic guidelines for the management of chronic ITP and stroke have contradictory goals. Although anticoagulation is mandated in acute stroke, ITP causes low platelet counts that increase bleeding complications.     

Assessment of levels of vascular endothelial growth factor in patients with ESRD and its possible role in cardiovascular morbidity and mortality

Patients with end-stage renal disease (ESRD) are known to have an elevation of a variety of abnormal thrombotic and inflammatory markers associated with high cardiovascular mortality. Vascular endothelial growth factor (VEGF) is also dysregulated in ESRD but not much is known about the serum levels of VEGF in patients with ESRD. Published reports suggest that elevated levels of VEGF may be protective to the kidney during periods of acute injury and may maintain local glomerular function. Impaired production of VEGF may lead to proteinuria, hypertension, and thrombotic microangiopathy. However, its role in chronic kidney disease or ESRD remains undefined. In our study, we analyzed blood samples of 52 patients with ESRD on stable hemodialysis regimen and measured predialysis serum levels of VEGF and compared these with blood samples obtained from 50 healthy volunteers in order to study differences between baseline levels of VEGF and also attempted to determine its role in ESRD-related cardiovascular mortality.     

Prevention of contrast‐induced acute kidney injury in patients with stable chronic renal disease undergoing elective percutaneous coronary and peripheral interventions: Randomized comparison of two preventive strategies

Objective : We compared use of intravenous (IV) normal saline (NS) to sodium bicarbonate (NaHCO₃) with or without oral N‐acetylcysteine (NAC) for prevention of contrast‐induced acute kidney injury (CI‐AKI). Background : CI‐AKI is associated with significant adverse clinical events. Use of NAC has produced variable results. Recently, intravenous hydration with NaHCO₃ for CI‐AKI prophylaxis has been adopted as standard treatment for patients with stable chronic renal disease undergoing catheterization procedures. Methods : We prospectively enrolled 320 patients with baseline renal insufficiency scheduled to undergo catheterization. Patients were randomly assigned to receive either IV NS ± NAC (n = 161) or IV dextrose 5% in water containing 154 mEq/l of NaHCO₃ ± NAC (n = 159). IV NS was administered at 1 ml/kg body weight for 12 hr preprocedure and 12 more hr postprocedure. IV NaHCO₃ was administered at 3 ml/kg body weight for 1 hr preprocedure followed by 1 ml/kg body weight postprocedure. A 1,200 mg oral dose of NAC was given 2–12 hr preprocedure and 6–12 hr postprocedure in 50% of patients in each study arm. CI‐AKI was defined as an increase of >0.5 mg/dl or >25% above baseline creatinine. Results : Overall incidence of CI‐AKI was 10.3%. There was no significant difference in incidence among the two groups (NS ± NAC 11.8% vs. NaHCO₃ ± NAC 8.8%, p = ns). Incidence of CI‐AKI increased with increasing age (p = 0.001), contrast agent use >3 ml/kg body weight (p = 0.038) and diuretic use (p = 0.005). Conclusion : Incidence of CI‐AKI was no different in the NaHCO₃ group compared to NS group, and NAC did not reduce CI‐AKI in the two study arms. © 2011 Wiley Periodicals, Inc.     

Synthesis,acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities,and molecular docking studies of a novel compound based on combination of flurbiprofen and isoniazide

Synthesis of a compound with balanced bioactivities against a specific target is always a challenging task. In this study, a novel compound (1) has been synthesized by combination of flurbiprofen and isoniazide and shows ∼2.5 times enhanced acetylcholinesterase (AChE) inhibition activity and ∼1.7 times improved butyrylcholinesterase (BuChE) inhibition activity compared to flurbiprofen and a standard drug (i.e. physostigmine). A comparative AutoDock study has been performed, based on the optimized structure, by the DFT/B3LYP method, which confirmed that compound (1) is more active against AChE and BuChE, with calculated binding energies of −12.9 kcal mol⁻¹ and −9.8 kcal mol⁻¹ respectively as compared to flurbiprofen and an eserine (physostigmine) standard for which the binding energy was calculated to be −10.1 kcal mol⁻¹ and −8.9 kcal mol⁻¹, respectively. A mixed mode of inhibition of AChE and BuChE with compound 1 was confirmed by Lineweaver–Burk plots. AChE and BuChE inhibition activity alongside docking results suggests that compound (1) could be used for treatment of Alzheimer''s disease. Moreover, compound (1) also exhibit better α-chymotrypsin activity compared to flurbiprofen. Furthermore, in vitro and in vivo analysis confirmed that compound (1) exhibit more activity and less toxicity than the parent compounds.

A novel compound (1) shows ∼2.5 and ∼1.7 times enhanced AChE inhibition activity and BuChE inhibition activity respectively compared to flurbiprofen and standard drug (i.e. physostigmine). It has also been confirmed by comparative AutoDock studies.     

Enoxaparin and abciximab adjunctive pharmacotherapy during percutaneous coronary intervention

Randomized controlled trials of patients with non-ST segment elevation acute coronary syndromes have established the superiority of enoxaparin (versus unfractionated heparin) for reducing adverse ischemic outcomes. Furthermore, adjunctive abciximab therapy during percutaneous coronary intervention (PCI) is associated with improved clinical outcomes. Since algorithms for integrating these pharmacotherapies have not been determined, patients undergoing elective PCI were enrolled into 2 distinct and separate studies conducted by the National Investigators Collaborating on Enoxaparin (NICE) study groups (NICE 1 and NICE 4 studies). Patients in NICE 1 were administered enoxaparin 1.0 mg/kg intravenously (without abciximab) and those enrolled in NICE 4 were administered a reduced dose (0.75 mg/kg) of enoxaparin in combination with standard-dose abciximab intravenously during PCI. Bleeding events and ischemic outcomes assessed in-hospital and at 30-days post-PCI were infrequent with either pharmacologic regimen. In the dose regimens studied, enoxaparin with or without abciximab appears to provide safe and effective anticoagulation during PCI. The combination of reduced-dose enoxaparin and abciximab was associated with a low incidence of adverse outcomes (bleeding or ischemic events). Additional studies may be required to establish the relative safety and efficacy of this new adjunctive pharmacologic strategy when compared with the combination of low-dose, weight-adjusted unfractionated heparin and abciximab.     

Transduction of a bacterial gene into mammalian cells.

The transduction of an Escherichia coli gene into mammalian cells is described. A supressor tRNA gene was linked to a simian virus 40 (SV40) vector in vitro and the recombinant was used to transfect rat embryo cells and monkey kidney cells. The hybrid SV40 genome, SV40-su+ III, retained genetic information required for autonomous replication and cellular transformation and had a 1300-base-pair DNA segment in the late gene region (between the restriction endonuclease sits Hpa II at 0.735 and EcoRI at 0/1.0 on the SV40 genetic map) replaced by an 870-base-pair bacterial DNA segment containing the suppressor tRNA gene, su+ III (tRNATyrsu+III). The structure and fate of the SV40-su+III chimera were determined by DNA reassociation kinetic analysis and restriction enzyme cleavage of the total cellular DNA from transformed rat embryo cells and persistently infected monkey cells. Hybridization with radiolabeled probes specific for vector (SV40) or su+III DNA sequences revealed primarily nonintegrated or free hybrid genomes. In cloned lines of both cell types, the bacterial DNA segment was recovered intact, as judged by the length of the segment excised by restriction endonucleases and its ability to hybridize to the radiolabeled bacterial DNA probe and not to the SV40 probe.     

Hepatic artery stenosis after liver transplant, managed with percutaneous angioplasty and stent placement.

Hepatic artery stenosis is a recognized vascular complication of orthotopic liver transplant that carries significant morbidity and mortality. The authors present a case of hepatic artery stenosis in a 50-year-old female successfully treated with balloon angioplasty and stent. This case report highlights the importance of percutaneous intervention as a preferred treatment option in patients with hepatic artery stenosis post-orthotopic liver transplant.