Cutting at the right place--the importance of selective limited proteolysis in the activation of proproteinase E

Proteinase E is a proteolytic enzyme which belongs to a distinct subfamily of chymotrypsin-like serine endopeptidases. Its proform from the bovine pancreatic system has been structurally analyzed by X-ray crystallography for the intact native form, with a 11-residue N-terminal activation peptide, in a ternary complex with chymotrypsinogen C and procarboxypeptidase A [Gomis-Rüth, F. X., Gómez, M., Bode, W., Huber, R. & Avilés, F. X. (1995) The three-dimensional structure of the native ternary complex of bovine pancreatic procarboxypeptidase A with proproteinase E and chymotrypsinogen C, EMBO J. 14, 4387-4394]. Also for a N-terminally truncated form, lacking the first 13 residues and called subunit III, a crystal structure is available [Pignol, D., Gaboriaud, C., Michon, T., Kerfelec, B., Chapus, C. & Fontecilla-Camps, J. C. (1994) Crystal structure of bovine procarboxypeptidase A-S6 subunit III, a highly structured truncated zymogen E, EMBO J. 8, 1763-1771]. Both structures are well defined by electron density, except for the first 7 residues of subunit III. However, both structures present large deviations of up to 2 nm in several regions, indicating that they correspond to two quite distinct states of low free energy, influenced by very few contacts made via the N-terminal segment. As no structure of an active proteinase E is known so far, pancreatic porcine elastase has been chosen as a model for this enzyme and an activation mechanism for this distinct serine endopeptidase subfamily is proposed.     

Selecting proteins with improved stability by a phage-based method

We describe a method for the stabilization of proteins that links the protease resistance of stabilized variants of a protein with the infectivity of a filamentous phage. A repertoire of variants of the protein to be stabilized is inserted between two domains (N2 and CT) of the gene-3-protein of the fd phage. The infectivity of fd phage is lost when the three domains are disconnected by the proteolytic cleavage of unstable protein inserts. Rounds of in vitro proteolysis, infection, and propagation can thus be performed to enrich those phage containing the most stable variants of the protein insert. This strategy discriminates between variants of a model protein (ribonuclease T1) differing in conformational stability and selects from a large repertoire variants that are only marginally more stable than others. Because fd phage are exceptionally stable and the proteolysis in the selection step takes place in vitro a wide range of solvent conditions can be used, tailored for the protein to be stabilized.     

Surgically induced astigmatism with superior and temporal incisions in cases of with-the-rule preoperative astigmatism

PURPOSE: To evaluate surgically induced astigmatism (SIA), postoperative astigmatism, and uncorrected visual acuity (UCVA) after cataract surgery with superior corneal, superior scleral, and temporal corneal 4.0 mm sutureless incisions in cases of preoperative with-the-rule (WTR) astigmatism. SETTING: Hopital des Quinze-Vingts, Paris, France. METHODS: This prospective evaluation included patients having phacoemulsification with foldable lens implantation through a 4.0 mm incision. Patients with preoperative WTR astigmatism were randomly assigned to 1 of 3 incisions: superior corneal (Group 1), superior scleral (Group 2), or temporal corneal (Group 3). All patients had autokeratometry preoperatively and postoperatively (1 day, 1 week, 1 month, 1 year). Surgically induced astigmatism using the vector method, postoperative astigmatism, and UCVA (patients whose spherical equivalent was with +/- 1 diopter) were evaluated. RESULTS: Ninety patients were included in the study; there were 30 in each incision group. One year postoperatively, Group 1 had 1.52 diopters (D) of SIA and 1.36 D of postoperative astigmatism; 53.5% of patients had a UCVA of 20/32 or better, Group 2 had 0.69 D of SIA (P < .05) and 0.67 D of postoperative astigmatism (P < .05); 82.7% of patients had a UCVA of 20/32 or better (P < .05). Group 3 had 0.69 D (P > .05), 0.98 D (P < .05), and 79.3% (P > .05), respectively. CONCLUSIONS: In this study, the superior corneal incision produced significant SIA, leading to high postoperative astigmatism and poor UCVA. The scleral and temporal incisions produced minimal SIA and good UCVA.     

Laparoscopic myomectomy. 102 cases

Myomectomy was performed by laparoscopy in 102 patients, according to a precise technique using the monopolar hook for the uterine incision and intraperitoneal sutures. Myomes were mostly removed through the suprapubic puncture site after fragmentation or by colpotomy. A laparotomy during the laparoscopic procedures was necessary in 2 cases. No complications were observed. A second-look laparoscopy or a cesarean section was performed in 24 cases. Post-operative adhesions were noted in 3 cases. In our experience, operative laparoscopy has several advantages over laparotomy and the risks of complications is low in selected cases.     

Laparoscopic surgery of large uterine fibromas. Operative technique and results

OBJECTIVE. To describe the technique of laparoscopic myomectomy for large myomas (5 cm and more) and to evaluate the results. RESULTS. Only myomas which are complicated (and/or resistant to properly conducted medical treatment) require surgical treatment. Between October 1, 1990 and October 31, 1994, we carried out 72 laparoscopic myomectomies for intramural myomas measuring 5 cm or more, in 71 patients. The operations lasted 130 +/- 60 min (range: 40-330 min). We converted to laparotomy for two cases (2.7%). We observed no serious per or postoperative complications. We never needed a repeat operation, whether by laparotomy or by laparoscopy. CONCLUSION. Despite these encouraging results, it must be remembered that the operation is lengthy and difficult and is reversed for laparoscopic surgeons perfectly familiar with endoscopic knot tying. Although it is a difficult technique, laparoscopic myomectomy is possible even for large myomas and those that are completely intramural. These results need to be assessed over the long term especially with respect to the risk of adhesions and the quality of the laparoscopic suture.     

PET as a support material for TiO2 in advanced oxidation processes

The use of polyethylene terephthalate (PET) as a support material for TiO₂ films in advanced oxidation processes (AOPs) for water treatment was investigated. A green, low‐cost immobilization procedure was developed and the amount of deposited photocatalyst ranged from 0.036 to 0.202 mg per cm² PET. Photocatalytic activity of the films was evidenced by degrading paracetamol solutions under UV radiation. The highest kinetic constants were observed for at least 0.09 mg TiO₂ per cm² PET. Scan electron microscopy (SEM) and energy‐dispersive X‐ray (EDX) analyses indicated 0.15 mg TiO₂ per cm² PET as enough to provide complete covering of the PET support. Characterization analyses were also performed with a film after 30 h of use in a UV/TiO₂/O₃ reactor. According to SEM analyses, the photocatalyst was not detached from the PET support, while EDX and gravimetric data indicated the possibility of the TiO₂ to have been contaminated by compounds present in the solution during the treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40175.     

Retrieval of linear optical functions from finite range spectra

There are many experimental situations in which infrared reflectivity spectra can be acquired only over a limited spectral range. It is therefore necessary to find computing procedures that allow the efficient analysis of such data. In this paper, we propose a new procedure labeled constrained finite range correction (CFRC) that can be advantageously substituted to multiply subtractive Kramers-Kronig relations. The constrained finite range correction is able to produce realistic results even when very little supplementary information is available. For semitransparent crystals, the hypothesis of the phase spectrum positiveness alone is often sufficient to compute satisfactory approximations of the optical functions. The efficiency of the new method is shown through the analysis of several synthetic and experimental spectra.     

Control-Sensitive Feature Selection for Lazy Learners

High sensitivity to irrelevant features is arguably the main shortcoming of simple lazy learners. In response to it, many feature selection methods have been proposed, including forward sequential selection (FSS) and backward sequential selection (BSS). Although they often produce substantial improvements in accuracy, these methods select the same set of relevant features everywhere in the instance space, and thus represent only a partial solution to the problem. In general, some features will be relevant only in some parts of the space; deleting them may hurt accuracy in those parts, but selecting them will have the same effect in parts where they are irrelevant. This article introduces RC, a new feature selection algorithm that uses a clustering-like approach to select sets of locally relevant features (i.e., the features it selects may vary from one instance to another). Experiments in a large number of domains from the UCI repository show that RC almost always improves accuracy with respect to FSS and BSS, often with high significance. A study using artificial domains confirms the hypothesis that this difference in performance is due to RC's context sensitivity, and also suggests conditions where this sensitivity will and will not be an advantage. Another feature of RC is that it is faster than FSS and BSS, often by an order of magnitude or more.