Purification of a 6.5 kDa protease inhibitor from Amazon Inga umbratica seeds effective against serine proteases of the boll weevil Anthonomus grandis.

A 6.5 kDa serine protease inhibitor was purified by anion-exchange chromatography from the crude extract of the Inga umbratica seeds, containing inhibitor isoforms ranging from 6.3 to 6.7 kDa and protease inhibitors of approximately 19 kDa. The purified protein was characterized as a potent inhibitor against trypsin and chymotrypsin and it was named I. umbratica trypsin and chymotrypsin inhibitor (IUTCI). MALDI-TOF spectra of the IUTCI, in the presence of DTT, showed six disulfide bonds content, suggesting that this inhibitor belongs to Bowman-Birk family. The circular dichroism spectroscopy indicates that IUTCI is predominantly formed by unordered and beta-sheet secondary structure. It was also characterized, by fluorescence spectroscopy, as a stable protein at range of pH from 5.0 to 7.0. Moreover, this inhibitor at concentration of 75 microM presented a remarkable inhibitory activity (60%) against digestive serine proteases from boll weevil Anthonomus grandis, an important economical cotton pest.

Crystallization, data collection and phasing of black-eyed pea trypsin/chymotrypsin inhibitor in complex with bovine beta-trypsin.

The black-eyed pea trypsin and chymotrypsin inhibitor (BTCI) is a Bowman-Birk-type inhibitor from Vigna unguiculata seeds. A complex of BTCI with bovine beta-trypsin was crystallized by the hanging-drop vapour-diffusion method with ammonium sulfate as precipitant. Crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 59.3, b = 61.8, c = 80.0 A. Diffraction data were collected to 2.36 A resolution and were processed to give an overall R(sym) of 0.137. The Matthews coefficient for one complex per asymmetric unit is 2.2 A(3) Da(-1), with a corresponding solvent content of 43%. After molecular replacement and initial refinement, the model gives an R(cryst) of 0.361 and an R(free) of 0.432.

[The angioplasty of chronic coronary occlusions with the excimer laser for debulking followed by stent implantation]. / Angioplastia de oclusões coronárias crónicas com laser excimer para debulking seguido de implantação de stent.

UNLABELLED: Coronary angioplasty (PCI) of chronic total occlusions (CTO), even when successful, are associated to less favourable long term results. The recent use of coronary stents has improved the long term outcome of those interventions. PURPOSE: To evaluate the short term results and long term occurrence of major adverse coronary events (MACE): death, MI, urgent revascularization and the need for a new target vessel revascularization (TVR) in patients with CTO who had previously been submitted to a PCI with excimer laser for plaque debulking followed by a provisional stent. POPULATION: From our database, we selected 19 patients with a mean age of 51 +/- 13 years (18 male) submitted to PCI between 1994 and 1998. Of those patients, 10 had had of a previous MI. Hypertension, smoking habits and hypercholesterolemia were present in 9 patients (42%). Two patients had diabetes. The main reason for PCI was stable angina in 16 patients (84%) and unstable in 3 patients (16%). Single-vessel disease was present in 18 patients (94%) and multiple-vessel in 1 patient (6%); left ventricular ejection fraction was preserved in 18 patients (94%). Single vessel PCI was performed in 16 patients (84%) and double vessel in 3 patients. Plaque debulking with excimer laser was performed in all patients, followed by 23 stents (Multilink--8; Gianturco Roubin--5; Palmaz Schatz--4; others--6). The mean clinical follow-up was 19 months. RESULTS: There were no major short-term clinical events (death, MI or urgent revascularization). During follow-up, TVR was only required in 5 patients (26%), all of them in the first 7 months after PCI. CONCLUSIONS: In the highly selected population, PCI for chronic total occlusion, with excimer laser plaque debulking followed by provisional stents, was a safe procedure with a very acceptable rate of new target vessel revascularization in the follow-up period.

Effects of denaturing and stabilizing agents on the inhibitory activity and conformational stability of Schizolobium parahyba chymotrypsin inhibitor.

The conformational stability of the Schizolobium parahyba chymotrypsin inhibitor (SPCI) was investigated based on conformational changes and inhibitory activity in the presence of chaotropic and stabilizing agents. At 90 degrees C, the half-lifetime of SPCI was 154 min, while in the presence of 1 M KCl and 20% PEG 20,000, it was drastically reduced to 6 and 3 min, respectively. In contrast, at 90 degrees C, the SPCI structure remained unaltered with the addition of 1 mM DTT and 56% glycerol. The reduction of the two disulfide bonds caused conformational changes in the SPCI without altering the inhibitory activity, suggesting that disulfide bonds are irrelevant to the maintenance of SPCI conformation. Unfolded structures were formed in the presence of 6 M GdnHCl, while in the presence of 8 M urea, destabilization was due to peptide bond rupture. These results suggest that the thermal inactivation of SPCI involves conformational changes and that hydrophobic and electrostatic interactions play a significant role, while the disulfide bonds are of secondary importance in maintaining the high thermal stability of SPCI.

[Syncope in a patient with Ebstein's anomaly and Wolff-Parkinson-White syndrome]. / Síncope em doente com anomalia de Ebstein e síndrome de Wolff-Parkinson-White.

We describe a clinical case of a patient with Ebstein's anomaly and syncope in Wolff-Parkinson-White's syndrome. After a radiofrequency ablation of an accessory atrioventricular pathway there was a different arrhythmia of ventricular origin. Although we have some doubts about their clinical relevance, we discuss the complex arrhythmic background, the medical management difficulties and the prognostic issues. There is an evaluation about ablation usefulness in this context regarding future attitudes in relation to other kinds of rhythm disorder.