Modification of the peroxygenative:peroxidative activity ratio in the unspecific peroxygenase from Agrocybe aegerita by structure-guided evolution.

Unspecific peroxygenase (UPO) is a heme-thiolate peroxidase capable of performing with high-selectivity C-H oxyfunctionalizations of great interest in organic synthesis through its peroxygenative activity. However, the convergence of such activity with an unwanted peroxidative activity encumbers practical applications. In this study, we have modified the peroxygenative:peroxidative activity ratio (P:p ratio) of UPO from Agrocybe aegerita by structure-guided evolution. Several flexible loops (Glu1-Pro35, Gly103-Asp131, Ser226-Gly243, Gln254-Thr276 and Ty293-Arg327) were selected on the basis on their B-factors and ΔΔG values. The full ensemble of segments (43% of UPO sequence) was subjected to focused evolution by the Mutagenic Organized Recombination Process by Homologous IN vivo Grouping (MORPHING) method in Saccharomyces cerevisiae. Five independent mutant libraries were screened in terms of P:p ratio and thermostability. We identified several variants that harbored substitutions at positions 120 and 320 with a strong enhancement in the P:p ratio albeit at the cost of stability. The most thermostable mutant of this process (S226G with an increased T50 of 2°C) was subjected to further combinatorial saturation mutagenesis on Thr120 and Thr320 yielding a collection of variants with modified P:p ratio and recovered stability. Our results seem to indicate the coexistence of several oxidation sites for peroxidative and peroxygenative activities in UPO.

Catecholamines and Paroxysmal Sympathetic Hyperactivity after Traumatic Brain Injury.

Paroxysmal sympathetic hyperactivity (PSH) affects a significant minority of people in the intensive care unit after severe traumatic brain injury. Systematic research has yet to elucidate or quantify the extent of the role of the catecholamines or adrenocortical and thyroid axis hormonal influences in the condition. Data were prospectively collected on 80 consecutive patients, 18 of whom developed clinical signs of PSH (22.5%). Catecholamine and hormonal data were collected sequentially at 4-h intervals or during and between episodes of PSH. Evaluated variables showed 200-300% increases in catecholamines and, to a lesser extent, adrenocortical hormones during paroxysms. The majority of PSH episodes (72%) were noted to be in response to an observable triggering event. These changes were not observed in subjects without PSH. These data go some way to explain why PSH produces adverse consequences in survivors of TBI with the condition.

Longitudinal analysis of maternal serum Follistatin concentration in normal pregnancy and preeclampsia.

OBJECTIVE: Follistatin (FST) is a regulator of the biological activity of activin A (Act A), binding and blocking it, which could contribute to the modulation of its pro-inflammatory activity during pregnancy. We sought to investigate, in this nested case-control study, FST serum levels during normal pregnancy and correlate it with the FST profile in preeclamptic pregnant women, normal pregnant women followed 3 months postpartum and eumenorrheic nonpregnant women throughout the menstrual cycle. SUBJECTS AND METHODS: Follistatin serum levels determined by ELISA, biochemical and anthropometric variables were measured in normal pregnant (n = 28) and preeclamptic (n = 20) women during three periods of gestation. In addition, FST serum levels were measured in a subset of normal pregnant women (n = 13) followed 3 months postpartum and in eumenorrheic nonpregnant women (n = 20) during the follicular and luteal phases of the menstrual cycle. RESULTS: Follistatin serum levels in the eumenorrheic nonpregnant and postpartum group were significantly lower when compared to levels throughout gestation (P < 0·01). Serum FST levels increased in each period of pregnancy analysed, being significantly higher towards the end of gestation (P < 0·01). FST levels were lower in late pregnancy in preeclamptic women compared to normal pregnant women (P < 0·05). Finally, FST levels were higher in the luteal phase when compared with the follicular phase of the menstrual cycle (P < 0·05). CONCLUSIONS: These analyses would permit the consideration that changes in FST levels during pregnancy contribute to the control of the Act A system.

[Extreme thrombocytopenia following abciximab therapy]. / Trombocitopenia extrema secundaria a abcixamab.

Antagonists of the glycoprotein IIb/IIIa receptor block the binding of fibrinogen and Von Willebrand factor to the platelet receptor. This effect can lead to bleeding and thrombocytopenia. We analyzed the incidence and clinical repercussions of severe thrombocytopenia (< 20 000 /microl) secondary to abciximab treatment in a prospective study of 375 patients (74% men) who underwent percutaneous coronary revascularization and received abciximab at our hospital. We recorded clinical and demographic characteristics, angiographic findings, laboratory results and platelet counts (before, 4 hours after and 12 hours after the procedure) and hematocrit. The incidence of severe acute thrombocytopenia was 1.1%. All patients were men, and none had relevant bleeding complications. Management consisted of monitoring the bleeding, discontinuing the drug and transfusing platelets. Clinicians should be alert to this complication during the initial hours after the administration of abciximab.