Application of LC/MS to determine specific activity variation in a series of sulfonamide tracers from the [35S]methane sulfonate reagent

The specific activities for a series of S‐35 tracers were found to vary from the decay‐corrected specific activity of the labeled reagent. If not known before the stock solution preparation and binding assay, this variation would have resulted in performing the assay at approximately two to three times over the targeted concentration, thereby leading to considerable error in the calculated binding and related conclusions. Copyright © 2012 John Wiley & Sons, Ltd.     

An antigenic domain of the Leishmania amazonensis nucleoside triphosphate diphosphohydrolase (NTPDase 1) is associated with disease progression in susceptible infected mice

An antigenic conserved B domain was previously identified within nucleoside triphosphate diphosphohydrolases (NTPDases) of plants and parasites. Now, the r-potDomain B, a 6× His-tag polypeptide belonging to the conserved B domain from the potato apyrase, and synthetic peptides LbB1LJ and LbB2LJ derived from the B domain from Leishmania NTPDase 1 were used as molecular tools for studies of the Leishmania amazonensis NTPDase 1. Widespread subcellular location of the specific NTPDase 1 was detected by Western blots of promastigote fractions and ultrastructural immunocytochemical microscopy using immune sera raised against these biomolecules. In addition, the L. amazonensis-infected BALB/c mice were evaluated at 12 to 120 days after infection, which progresses showing typical nodular lesion. High antibody reactivity with either r-potDomain B, LbB1LJ, or LbB2LJ was found in L. amazonensis-infected BALB/c mice indicating the antigenicity of the B domain from NTPDase 1 isoform. The IgG1 antibody reactivity significantly increased at 90–120 days postinfection, 18- to 24-fold when compared to the 12th day, and remained elevated even at 120th after infection, coinciding with the most active stage of the disease. In contrast, significantly higher IgG2a antibody reactivity with each biomolecule was observed at 40th day, about two- to fourfold higher than those found at 12th or 20th day, and decreased along 120-day period. Apparently, the conserved B domain is capable to induce IgG2a production in early disease stages. All together, these results suggest that r-potDomain B or synthetic peptides could be molecular starting points in experimental protocols of immunotherapy and/or vaccination for leishmaniasis.     

A Comparison of the Effects of Oral Glutamine Dipeptide,Glutamine, and Alanine on Blood Amino Acid Availability in Rats Submitted to Insulin-Induced Hypoglycemia

We compared the effects of oral administration of high-dose or low-dose glutamine dipeptide (GDP), alanine (ALA), glutamine (GLN), and ALA + GLN on the blood availability of amino acids in rats submitted to insulin-induced hypoglycemia (IIH). Insulin detemir (1 U/kg) was intraperitoneally injected to produce IIH; this was followed by oral administration of GDP, GLN + ALA, GLN, or ALA. We observed higher blood levels of GLN, 30 min after oral administration of high-dose GDP (1000 mg/kg) than after administration of ALA (381 mg/kg) + GLN (619 mg/kg), GLN (619 mg/kg), or ALA (381 mg/kg). However, we did not observe the same differences after oral administration of low-dose GDP (100 mg/kg) compared with ALA (38.1 mg/kg) + GLN (61.9 mg/kg), GLN (61.9 mg/kg), or ALA (38.1 mg/kg). We also observed less liver catabolism of GDP compared to ALA and GLN. In conclusion, high-dose GDP promoted higher blood levels of GLN than oral ALA + GLN, GLN, or ALA. Moreover, the lower levels of liver catabolism of GDP, compared to ALA or GLN, contributed to the superior performance of high-dose GDP in terms of blood availability of GLN.     

Massive organ embolization from primary aortic thrombosis

A 49-year-old woman was hospitalized for acute left foot arterial ischemia. Arterial Doppler revealed occlusion of the dorsalis pedis and posterior tibial arteries. A computed tomography angiography performed to assess abdominal pain showed hepatic, splenic, renal and pancreatic infarctions. A splenic artery embolism and a small aortic wall thrombus at the celiac trunk were identified. No radiological signs of aortic atherosclerosis were found. No predisposing conditions for secondary aortic thrombosis or intracardiac embolic sources were detected. It was determined that primary aortic thrombosis, a rare though potentially serious condition, was to blame. Isolated aortic mural thrombosis therapy is not well established, although systemic anticoagulation, thrombolysis, thromboaspiration, endovascular stent grafting and surgical thrombectomy have been attempted with varying success. In our patient, systemic anticoagulation therapy was initiated and resulted in aortic thrombus resolution. Close clinical follow-up is crucial, as the aortic thrombus can recur despite anticoagulation and aggressive control of the atherosclerotic risk factors.     

Bioactivation to an aldehyde metabolite—Possible role in the onset of toxicity induced by the anti-HIV drug abacavir

Aldehydes are highly reactive molecules, which can be generated during numerous physiological processes, including the biotransformation of drugs. Several non-P450 enzymes participate in their metabolism albeit alcohol dehydrogenase and aldehyde dehydrogenase are the ones most frequently involved in this process. Endogenous and exogenous aldehydes have been strongly implicated in multiple human pathologies. Their ability to react with biomacromolecules (e.g. proteins) yielding covalent adducts is suggested to be the common primary mechanism underlying the toxicity of these reactive species.