Physical-chemical characterization and stability study of alpha-trypsin at pH 3.0 by differential scanning calorimetry.

alpha-Trypsin is a serine-protease with a polypeptide chain of 223 amino acid residues and six disulfide bridges. It is a globular protein with predominance of antiparallel ss-sheet secondary structure and it has two domains with similar structures. In the present work, a stability study of alpha-trypsin in the acid pH range was performed and some physical-chemical denaturation parameters were measured by using differential scanning calorimetry (DSC). The alpha-trypsin has a shelf-life (t(95%)) of about 10 months at pH 3.0 and 4 degrees C and its hydrolysis into the psi-trypsin isoform is negligible during 6 months. The observed ratio DeltaH(cal)/DeltaH(vH) is close to unity, which suggests the occurrence of a two-state transition. At pH 3.0, alpha-trypsin unfolded with T(m) = 325.9 K and DeltaH = 99.10 kcal mol(-1), and the change in heat capacity between the native and unfolded forms of the protein was estimated to be 1.96+/-0.18 kcal mol(-1)K(-1). The stability of alpha-trypsin calculated at 298 K was DeltaG(U)=6.10 kcal mol(-1) at pH 3.0. These values are in the range expected for a small globular protein. These results show that the thermodynamic parameters of unfolding of beta-trypsin do not change substantially after its conversion to alpha-trypsin.

Spectrum of pleural involvement in sarcoidosis.

Pleural involvement has generally been considered an unusual aspect of sarcoidosis. In this paper, five previously unreported cases of sarcoidosis involving the pleura were discussed. Pleural sarcoidosis may be manifested by the presence of a pleural effusion, and the diagnosis is based on the exclusion of all other possible causes and the demonstration of noncaseating granulomas in the pleura. When the pleura is involved without effusion, it may only be recognized if noncaseating granulomas involving the pleura are looked for specifically. Including the five cases form this study, there have been 73 cases of pleural sarcoidosis reported, but only 37 have been verified by histologic evidence. When strict diagnostic criteria are used, clinical involvement of the pleura in sarsoidosis remains an unusual entity, but it may be that histologic involvement of the pleura is more common than generally appreciated.

Value of right-sided cardiac catheterization in patients undergoing left-sided cardiac catheterization for evaluation of coronary artery disease.

The value of right-sided cardiac catheterization was assessed prospectively in 200 patients undergoing left-sided catheterization for evaluation of known or suspected coronary artery disease. Before catheterization, data from right-sided catheterization was not felt to be necessary for clinical management. There were 6 +/- 2 extra minutes of procedure time and 86 +/- 63 extra seconds of fluoroscopy time used. Abnormalities were detected in 69 (35%) patients. These findings were unexpected in 37 of these patients and in 3 patients, further evaluation was prompted. However, management was altered in only 3 (1.5%) patients as a result of data obtained by right-sided catheterization. In conclusion this additional procedure rarely adds clinically useful information about patients undergoing left-sided catheterization and angiography for coronary artery disease without a clinical indication for right-sided catheterization.