Yielded Success Rates Research Articles

Reviews From Current Literature

Reviews From Current Literature

Development of bioassays using the bovine model to measure the efficiency of SCNT in humans

Development of bioassays using the bovine model to measure the efficiency of SCNT in humans

Comparative evaluation of 11 scoring functions for molecular docking.

Eleven popular scoring functions have been tested on 100 protein-ligand complexes to evaluate their abilities to reproduce experimentally determined structures and binding affinities. They include four scoring functions implemented in the LigFit module in Cerius2 (LigScore, PLP, PMF, and LUDI), four scoring functions implemented in the CScore module in SYBYL (F-Score, G-Score, D-Score, and ChemScore), the scoring function implemented in the AutoDock program, and two stand-alone scoring functions (DrugScore and X-Score). These scoring functions are not tested in the context of a particular docking program. Instead, conformational sampling and scoring are separated into two consecutive steps. First, an exhaustive conformational sampling is performed by using the AutoDock program to generate an ensemble of docked conformations for each ligand molecule. This conformational ensemble is required to cover the entire conformational space as much as possible rather than to focus on a few energy minima. Then, each scoring function is applied to score this conformational ensemble to see if it can identify the experimentally observed conformation from all of the other decoys. Among all of the scoring functions under test, six of them, i.e., PLP, F-Score, LigScore, DrugScore, LUDI, and X-Score, yield success rates higher than the AutoDock scoring function. The success rates of these six scoring functions range from 66% to 76% if using root-mean-square deviation < or =2.0 A as the criterion. Combining any two or three of these six scoring functions into a consensus scoring scheme further improves the success rate to nearly 80% or even higher. However, when applied to reproduce the experimentally determined binding affinities of the 100 protein-ligand complexes, only X-Score, PLP, DrugScore, and G-Score are able to give correlation coefficients over 0.50. All of the 11 scoring functions are further inspected by their abilities to construct a descriptive, funnel-shaped energy surface for protein-ligand complexation. The results indicate that X-Score and DrugScore perform better than the other ones at this aspect.

Site-directed mutagenesis by inverse PCR.

Site-directed mutagenesis has revolutionized the study of protein structure and function by enabling the controlled and systematic production of mutant proteins. Early methods of site-directed mutagenesis involved the use of a mutated oligonucleotide primer to prime synthesis of a target single-stranded DNA template. These approaches were very inefficient, yielding success rates of 1–5% (). A dramatic improvement in the efficiency of generating mutations resulted from the use of single-stranded, uracil-containing DNA molecules isolated from ung − dut− Escherichia coli strains (see Chapter 3). Again, the mutation is introduced in a mutated oligonucleotide primer. Selection against the wild-type sequence parent DNA occurs on transformation into wild-type E. coli. Mutagenesis by this method was relatively efficient, with rates of 15–35%, but required a number of subcloning steps involving single-stranded M13 phage clones (). It was only following the development of the polymerase chain reaction (PCR) that the two concepts were combined, dramatically improving the efficiency of the whole procedure.

Comparing Clinical Automated, Medical Record, and Hybrid Data Sources for Diabetes Quality Measures

Little is known about the relative reliability of medical record and clinical automated data, sources commonly used to assess diabetes quality of care. The agreement between diabetes quality measures constructed from clinical automated versus medical record data sources was compared, and the performance of hybrid measures derived from a combination of the two data sources was examined. Medical records were abstracted for 1,032 patients with diabetes who received care from 21 facilities in 4 Veterans Integrated Service Networks. Automated data were obtained from a central Veterans Health Administration diabetes registry containing information on laboratory tests and medication use. Success rates were higher for process measures derived from medical record data than from automated data, but no substantial differences among data sources were found for the intermediate outcome measures. Agreement for measures derived from the medical record compared with automated data was moderate for process measures but high for intermediate outcome measures. Hybrid measures yielded success rates similar to those of medical record-based measures but would have required about 50% fewer chart reviews. Agreement between medical record and automated data was generally high. Yet even in an integrated health care system with sophisticated information technology, automated data tended to underestimate the success rate in technical process measures for diabetes care and yielded different quartile performance rankings for facilities. Applying hybrid methodology yielded results consistent with the medical record but required less data to come from medical record reviews.

Randomized Study Comparing Two Techniques of Conization: Cold Knife versus Loop Excision

Objective. To compare the histomorphologic and colposcopic results of cold knife conization and loop excision.Methods. Sixty-six women were randomly allocated to have the cone specimen removed by cold knife excision (n = 38) or loop excision (n = 28). Subjects eligible for inclusion were those who presented histologically verified grade 3 cervical intraepithelial neoplasia (CIN) or grade 2 CIN with squamocolumnar junction not seen.Results. The mean height of the cone specimens was greater in the cold knife group [18.9 mm (SD = 5.5) and 12.8 mm (SD = 4.3), respectively; P = 0.0001], as was the frequency of clear margins (100 and 80%, respectively; P = 0.001). In the loop excision group, thermal injuries were present in half of the cone sections. The median (range) thickness of thermal injury was 0.98 mm (0–1.5 mm) in the ectocervix and 0.95 mm (0–1.75 mm) in the endocervix. Histologic evaluation of the endocervical margins was not possible in 2 cases (7%). At follow–up colposcopy, evaluation of the entire squamocolumnar junction was possible in 15 (39%) and 20 (71%) women, respectively (P < 0.01). Four patients in the cold knife group and 6 in the loop group had histologically confirmed persistent dysplasia (P > 0.05), yielding success rates of 90 and 79%, respectively (P > 0.05).Conclusions. Loop excision provides a sample that is adequate for histologic evaluation in most cases, results in the same success rate as cold knife conization, and allows optimal colposcopic surveillance in significantly more cases than cold knife excision.

Treatment of Carpal and Digital Ganglions by Simple Aspiration, or Aspiration and Injection of Corticosteroid And/Or Hyaluronidase

This retrospective study examined the treatment outcome of 178 carpal and digital ganglion cysts by simple aspiration or aspiration and injection of corticosteroid (triamcinolone acetonide 40 mg/mL) and/or hyaluronidase in 174 patients between 1987 and 1995. A total of 106 ganglions were treated with aspiration and triamcinolone acetonide injection; the cumulative cure rates were 45.3%, 50.0% and 53.8% following one, two or three treatments, respectively. The cure rates were similar in 23 ganglions in the hyaluronidase group: 43.5%, 52.2% and 56.5%, respectively. Seventeen of the 23 ganglions treated with a combination of triamcinolone acetonide and hyaluronidase recurred, yielding success rates of 17.4% and 26.1% following two or three treatments, respectively. Twenty-six ganglions were treated with simple aspiration. Of these, 23 were volar digital ganglions. The success rates were 61.5% and 69.2% following one or two treatments, respectively. The overall success rate was 94 of 178 (52.8%) after a maximum of three treatments, regardless of the type of treatment and the anatomical location of the ganglions. This study provided baseline data following nonoperative management of ganglions; the data can be compared with those from a planned prospective randomized clinical trial involving the use of rolitetracycline as a sclerosing agent, which is currently under review by the Ethics Committee at the authors’ institution.

Failure strengths of suture versus biodegradable arrow for meniscal repair: an in vitro study.

Advances in our understanding of meniscal function and consequences of menisectomy have spawned meniscal repair techniques that yield success rates approaching 90% in properly selected patients. Biodegradable implants have been fashioned for meniscal fixation to simplify the technique and minimize neurovascular complications. We performed the current study to determine the in vitro biomechanical behavior of the BIOFIX Meniscal Arrow, a polylactic acid tack developed for meniscal repair. Eight pairs of menisci were harvested from cadaveric knees kept frozen before testing. Peripheral vertical tears were created in the posterior horn of all menisci, and each was subsequently repaired using a vertical loop suture of 2-0 Ethibond and a Meniscal arrow. Ultimate load to failure of each method was determined on a Hounsfield H25KM Universal Testing machine. The mean failure load for the suture group was 58.3 N compared with the Arrow group mean of 29.6 N (P < .001). All sutures failed by rupture at the knot but did not pull through the meniscus. All but one of the arrows failed by pulling out of the meniscus. The Arrows also permitted gapping at the repair site at considerably lesser loads than the sutures subject to strain. The concept of a biodegradable tack is appealing. Vertical loop sutures should be the standard by which their biomechanical performance is judged. We suggest modifications to the Arrow design that could enhance the fixation strength of this implant.

PRIMARY ABLATION OF ATRIAL FLUTTER AND ATRIAL FIBRILLATION

Direct treatment of atrial flutter and atrial fibrillation--that is, attempting to prevent arrhythmia recurrences by ablating atrial tissue--has been a challenge because of uncertainty about the location of optimal target tissues as well as the amount of atrial tissue requiring destruction to effect cure. Advances have yielded success rates for ablation of the common form of atrial flutter comparable to those for other types of supraventricular tachycardia and provide reason for optimism about the use of catheter techniques, to treat atrial fibrillation definitively. This article discusses some of these advances as well as the current status of catheter ablation for atrial flutter and atrial fibrillation and, finally, what the future may bring.

Psychiatry

Last year's congressionally mandated reunion of the National Institute of Mental Health with the National Institutes of Health signaled recognition of the maturity of basic and clinical psychiatric research. This maturity is evident in the body of epidemiologic, economic, and treatment data, presented to the President's Task Force on National Health Care Reform, that convincingly dispels three key myths about mental illness: Mental illness is not definable. In fact, the diagnostic reliability for diagnoses of major mental illnesses equals that achieved for diagnoses in other areas of medicine. Multiple clinicians independently agree on the diagnosis of a major mental disorder approximately 80% of the time.¹ Mental illnesses are not treatable, or "everything sort of works for everything." In fact, outcome research documents that specific treatments for major mental disorders yield success rates in the 60% to 80% range. When assessed by the same criteria applied to determine "successful outcome" of

Using Parallel Computers To Solve the Phase Problem of X-Ray Crystallography

Direct methods are commonly used by crystallogra phers to determine relatively small crystal structures. However, existing techniques do not appear to be ex tensible to larger structures. The recent development of a solution strategy called Shake-and-Bake, aimed at determining structures via local minimization and re peated Fourier transformations, allows for implicit con straints to be included. In this article, a description of the Shake-and-Bake algorithm is given, along with a detailed description of master/slave MIMD implemen tations on a network of Sun workstations, an Intel iPSC/860 Hypercube, and a Connection Machine CM-5. Our experimental results on known structures, includ ing gramicidin A, are extremely encouraging. For ex ample, based on efficient implementations of Shake- and-Bake on the iPSC/860 and CM-5, for known struc tures of 28, 84, and 127 nonhydrogen atoms, we obtain success rates of 19%, 1%, and 0.2%, as opposed to existing methods, which yield success rates of ap proximately 6%, 0.006%, and 0.0002%, respectively.

Radiofrequency catheter ablation of accessory pathways: A learning experience

Success rates of approximately 90% have recently been reported with radiofrequency catheter ablation of accessory pathways. This study determined whether this success could be repeated using a conservative approach generally limiting fluoroscopy time to 1 hour. Consecutive patients referred for management of arrhythmias associated with accessory atrioventricular pathways were included over a 9-month period. Ablation was attempted in 75 patients with 84 pathways. Overall success rate (including second attempts in 9 patients) was 60 of 84 accessory pathways (71%). Success rates for the first 3 months (n = 23) were 52%, the second 3 months (n = 23) 60% and the last 3 months (n = 38) 90%. Success rate varied with pathway location, with left lateral pathways having the best early success rates. Mean fluoroscopy time for successful procedures of 33 ± 21 minutes was shorter than the time for unsuccessful procedures of 63 ± 24 minutes (p = 0.001). There were no major complications and no patients with successful procedures (n = 53) have had recurrence of accessory pathway conduction or reciprocating tachycardia (follow-up 1 to 10 months). A conservative approach can yield success rates approaching 90% in a short time. The absence of major complications supports earlier reports suggesting that radiofrequency catheter ablation of accessory pathways is a reasonable first-line therapy in the Wolfff-Parkinson-White syndrome.

Anterior cruciate ligament reconstruction using quadriceps patellar tendon graft

Eighty-three patients with ACL reconstructions using the quadriceps patellar tendon graft were evaluated in a 10 year (mean, 5.5 years) follow-up study. A five-part analysis, consisting of physical examination, questionnaire, Genucom analysis, operative note review, and radiographs, was performed. Seventy-six percent were categorized as satisfactory. Ninety-two percent were content with their results, while only 4% were unsatisfied. Ninety-three percent of the patients had no significant pain and 95% had no giving way postreconstruction. Ninety-two percent had no more than a mild functional deficit. Eighty-seven percent and 90% of the patients had no significant Lachman or pivot shift by examination, respectively. Our results showed no increase in failure over time (1 to 10 years), although those operated on during the initial 5 years showed more radiographic degenerative changes. Plotting our results in classification systems of other authors yielded success rates as good as or better than those using our own criteria. An objective means by which to quantify laxity did not reliably correlate with the quantifying of laxity made by physical examination. Only the lack of a formal rehabilitation program greater than 4 months postoperatively and repaired tears of the medial or lateral collateral ligaments proved to be significant risk factors for poor recovery.

Assessing alcoholism treatment effectiveness. A comparison of three evaluative measures.

The success rates of patients in an alcoholism treatment unit were evaluated according to three criteria: vocational rehabilitation, abstinence and a behavioral rating scale. The three measures yielded success rates of 70, 34 and 62%, respectively.