Aspirin

Vitamin C (L-ascorbic acid) has a major biological role as a natural antioxidant. Aspirin belongs to the nonsteroidal anti-inflammatory drugs and functions as an antioxidant via its ability to scavenge-OH radicals. Bovine serum albumin (BSA) is the major soluble protein constituent of the circulatory system and has many physiological functions including transport of a variety of compounds. In this report, the competitive binding of vitamin C and aspirin to bovine serum albumin has been studied using constant protein concentration and various drug concentrations at pH 7.2. FTIR and UV–Vis spectroscopic methods were used to analyze vitamin C and aspirin binding modes, the binding constants and the effects of drug complexation on BSA stability and conformation. Spectroscopic evidence showed that vitamin C and aspirin bind BSA via hydrophilic interactions (polypeptide and amine polar groups) with overall binding constants of Kvitamin C-BSA = 1.57 × 104 M−1 and Kaspirin-BSA = 1.15 × 104 M−1; assuming that there is one drug molecule per protein. The BSA secondary structure was altered with major decrease of α-helix from 64% (free protein) to 57% (BSA-vitamin C) and 54% (BSA-aspirin) and β-sheet from 15% (free protein) to 6–7% upon drug complexation, inducing a partial protein destabilization.► The binding constant of vitamin C-BSA was measured higher than aspirin-BSA. ► At low drugs concentration, no major protein conformational changes occur. ► At high drugs contents, significant decrease of secondary structures was observed. ► A partial protein destabilization was occurred at high drug concentrations. ► BSA can be considered as a good carrier for vitamin C and aspirin in vitro.

A derivative spectrophotometric method was developed for the assay of a ternary mixture of aspirin (ASP), paracetamol (PAR) and salicylic acid (SAL). The method is based on the use of the first and second derivatives of the ratio spectra and measurement at zero-crossing wavelengths. The ratio spectra were obtained by dividing the absorption spectrum of the mixture by that of one of the components. The concentration of the other components are then determined from their respective calibration curves treated similarly. The described method was applied for the determination of these combinations in synthetic mixtures and dosage forms. The results obtained were accurate and precise.

The hypothesis that physiologically activeconcentrations of salicylic acid (SA) and itsderivatives can confer stress tolerance in plants wasevaluated using bean (Phaseolus vulgaris L.) andtomato (Lycopersicon esculentum L.). Plantsgrown from seeds imbibed in aqueous solutions (0.1--0.5 mM) of salicylic acid or acetyl salicylic acid(ASA) displayed enhanced tolerance to heat, chillingand drought stresses. Seedlings acquired similarstress tolerance when SA or ASA treatments wereapplied as soil drenches. The fact that seedimbibition with SA or ASA confers stress tolerance inplants is more consistent with a signaling role ofthese molecules, leading to the expression oftolerance rather than a direct effect. Induction ofmultiple stress tolerance in plants by exogenousapplication of SA and its derivatives may have asignificant practical application in agriculture,horticulture and forestry.

Rekristalisasi adalah teknik pemurnian suatu zat padan dan campuran atau pengotornyayang dilakukan dengan cara mengkristalkan kembali zat tersebut setelah dilarutkan dalam pelarut (sovlen) yang sesuai atau cocok. Ada beberapa syarat agar suatu pelarut dapatdigunakan dalam proses rekristalisasi, yaitu memberikan perbedaan daya larut yang cukup besar antara zat yang dimurnikan dengan zat pengotornya tidak meninggalkan zat pengotor  pada kristal dan mudah dipisahkan dari kristalnya.

Each individual has an inherent variable risk of bleeding linked to genetic or acquired abnormal platelet number or platelet dysfunction. In contrast, it is less obvious that the variability of platelet phenotypes (number, mean platelet volume, function) may contribute to the variable individual risk of thrombosis. Interindividual variability of platelet indices or function may be either due to acquired factors, such as age, sex, metabolic variables, smoke, dietary habits, and ongoing inflammation, or due to genetic factors. Acquired variables explain a small portion of the heterogeneity of platelet parameters. Genetic factors, instead, appear to play a major role, although a consistent portion of such a genetic variance has not yet been attributed to any specific genetic factor, possibly due to the high number of DNA loci potentially involved and to the limited effect size of each individual SNP. A portion of variance remains thus unexplained, also due to variability of test performance. A major contradiction in present platelet knowledge is, indeed, the difficulty to reconcile the universally accepted importance of platelet indices or function and the lack of reliable platelet parameters in cardiovascular risk prediction models. Trials on antiplatelet drugs were generally designed to select a homogeneous sample, whose results could be applied to an "average subject," tending to exclude the deviation/extreme values. As the current indications for antiplatelet treatment in primary or secondary prevention of ischemic vascular disease still derive from the results of such clinical trials where platelet function and its variability was not investigated, we cannot at present rely upon any current platelet test to either initiate, or monitor, or modify or stop treatment with any antiplatelet drug. Evidence is, however, increasing that traditional platelet aggregometry and other more recently developed platelet function assays could be useful to optimize antiplatelet therapy and to predict major adverse cardiac events.The observation of interindividual differences in platelet response to antiplatelet drugs has enlarged the spectrum and the possible clinical relevance of the variability of platelet indices or function. The development of "personalized medicine" will benefit from the concepts discussed in this chapter.

... 7 Lopaciuk S, Bykowska K, Kwiecinski H, Czlonkowska A, Kuczynska-Zardzewialy A. Protein Z in young survivors of ischemic stroke. ... J Neurol 2003; 250: 63–6. 10 Adams HP Jr, Bendixen BH, Kappelle LJ, Biller J, Love BB, Gordon DL, Marsh EE III and the TOAST Investigators. ...

To review systematically the clinical effectiveness and the cost-effectiveness of clopidogrel used in combination with standard therapy including aspirin, compared with standard therapy alone for the treatment of non-ST-segment elevation acute coronary syndromes (ACS). Electronic databases. Manufacturers' submissions. Studies were selected using rigorous criteria. The quality of randomised controlled trials (RCTs) was assessed according to criteria based on NHS CRD Report No. 4, and the quality of systematic reviews was assessed according to the guidelines for the Database of Reviews of Effect (DARE) criteria. The quality of economic evaluations was assessed according to a specifically tailored checklist. The clinical effectiveness and cost-effectiveness of clopidogrel in combination with standard therapy compared with standard therapy alone were synthesised through a narrative review with full tabulation of the results of the included studies. In the economic evaluations, a cos...

Increased experience with free-tissue transfer has minimized flap loss secondary to microvascular thrombosis, yet pharmacologic antithrombotic prophylaxis continues to be used routinely. Currently there is no consensus on the ideal pharmacologic agent, dosing, or efficacy. Low-molecular-weight dextran has been widely used for prophylaxis due to its properties of volume expansion and enhanced microrheology. Significant systemic morbidity (pulmonary morbidity, cardiac morbidity, anaphylaxis) is known to occur with use of low-molecular-weight dextran. The purpose of this study was to evaluate morbidity associated with postoperative low-molecular-weight dextran and aspirin prophylaxis in head and neck microsurgery patients. This study was a randomized prospective analysis of 100 consecutive patients undergoing microvascular reconstruction for head and neck malignancy during a 2-year period. Patients were randomized into one of three postoperative antithrombotic prophylaxis treatment groups: low-molecular-weight dextran 20 cc/hour for 48 hours (n = 35), low-molecular-weight dextran 20 cc/hour for 120 hours (n = 32), or aspirin 325 mg/day for 120 hours (n = 27). Six patients were excluded intraoperatively due to the need for systemic heparin therapy. Treatment groups were compared for age, sex, prior medical problems, duration of anesthesia, and intraoperative fluid intake. Flap outcome and the incidence of local and systemic complications were evaluated in the treatment groups. Patient ages ranged from 12 to 84 years (mean age, 58 years). No significant difference was found among the treatment groups with respect to age, sex, prior medical problems, duration of anesthesia, intraoperative fluid intake, and the distribution of donor and recipient sites. There were no total flap losses and two partial flap losses in this series. Three flaps were reexplored and all were salvaged. The incidence of systemic complications (congestive heart failure, myocardial infarction, pulmonary edema, pleural effusion, and pneumonia) was as follows: low-molecular-weight dextran 120 hours, 51 percent; low-molecular-weight dextran 48 hours, 29 percent; and aspirin, 7 percent. Analysis of these data suggests that the method of prophylaxis had no effect on overall flap survival. However, the incidence of systemic complications was significantly related to the method of prophylaxis, with patients receiving low-molecular-weight dextran 120 hours and 48 hours at a 7.2 and 3.9 times greater relative risk, respectively, of developing a systemic complication compared with patients receiving aspirin. The results of this study have eliminated the routine use of low-molecular-weight dextran prophylaxis at our institution in an effort to reduce morbidity in head and neck microsurgical reconstruction.

Conclusion: There was no evidence of an increased risk for UGI bleeding when duloxetine was taken with prescription NSAIDs or aspirin.

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Despite well-documented efficacy, recurrent thrombotic event occurrences, particularly stent thrombosis, have been repeatedly demonstrated in stented patients treated with aspirin and clopidogrel. The latter observation stimulated the close scrutiny of the pharmacodynamic effects of clopidogrel and revealed the 'wide variability' and the phenomenon of 'antiplatelet resistance'. High on-treatment platelet reactivity to ADP (HPR) during clopidogrel therapy is an independent risk factor for ischemic event occurrences in post-percutaneous coronary intervention (post-PCI) patients. Recent observational studies demonstrated a link between low on-treatment platelet reactivity to bleeding. The concept of a 'therapeutic window' of P2Y12 receptor reactivity associated with both ischemic event occurrence (upper threshold) and bleeding risk (lower threshold) has been proposed. An update on and a brief review of the current knowledge on antiplatelet resistance were presen...