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At least 55 records · Page 3Linked to original sources
PubMed1991

The application of computational methods to the study of enzyme catalysis by triose-phosphate isomerase and stabilities of variants of bacteriophage T4 lysozyme.

We review our research on triose-phosphate isomerase and bacteriophage T4 lysozyme. In our studies over the last ten years we have used electrostatic potentials, computer graphics, quantum mechanics, molecular mechanics, molecular dynamics and free energy calculations to try to understand why triose-phosphate isomerase is such an efficient enzyme and why its efficiency is dramatically decreased by several site-specific mutations. For T4 lysozyme we have used free energy methods to analyse and try to understand why Thr-157----Val and Thr-157----Ala mutations decrease protein stability by about 1-2 kcal/mol.

Amino Acid Sequence↗
PubMed1991

A computer method for visual presentation and programmed evaluation of labor.

Manual graphing of the progress of labor is considered useful but is not often done. The early detection of some deviations requires special graphics aids. Our objective was to develop an easy-to-use computer program for the integrated visual presentation of information characterizing the progress of labor. Through the use of inexpensive personal computers equipped with graphics monitors, the program provides a combined graphics display of timed progressive cervical dilatation, fetal station, and stimulation of uterine activity (oxytocin infusion). For the early detection of abnormalities, phase-specific normal ranges (reference areas) are displayed. In addition, protraction/arrest as well as precipitate labor disorders are highlighted and computer messages are displayed. The program was evaluated through the assessment of 405 labors entered into a local area network of computers. On average, the program identified 1.5 abnormalities per recorded labor (2.0 for labors resulting in vaginal delivery). The graphic presentation of the labor curve, produced within 3 seconds, displayed 27% more information than the tabular format on the same screen area and provided a single-screen display of the labor curve even for patients with excessive data. The computer-generated display of labor curves facilitates visual presentation and interpretation of labor progress and can also help to translate quality assurance criteria into clinical practice.

Computer Graphics↗
PubMed1992

Computer methods for locating kinetoplastid cryptogenes.

RNA editing in the mitochondria of kinetoplastid protoza involves the insertion and/or deletion of precise numbers of uridine residues at precise locations in the numbers of uridine residues at precise locations in the transcribed RNA of certain genes. These genes are known as cryptogenes. In this paper we study computational algorithms to search for unknown cryptogenes and for the associated templates for insertion of uridines, gRNA sequences. The pairwise similarity search algorithm of Smith and Waterman (1) is modified to study this problem. The algorithm searches for unknown gRNAs given the cryptogene sequence. The method is tested on 4 known cryptogenes from L.tarentolae which are known to have 7 associated gRNAs. The statistical distribution of the longest gRNA when comparing random sequences is derived. Finally we develop an algorithm to search for cryptogenes using amino acid sequences from related proteins.

Algorithms↗
PubMedDate not supplied

[Algorithms and computation methods of diagnostic coefficients in dynamic scintigraphy of skeleton and skeletal muscles].

The paper is concerned with a program for data processing of dynamic scintigraphy of the skeleton and skeletal muscles using 99mTc-sodium 1-hydroxy-ethane-1, 1-diphosphonate. Employing gamma-chamber computer the program enables rapid and precise computation of the coefficient of RP elimination from the blood and the coefficients of RP accumulation by the bones and muscle tissue. Based on those coefficients one can make diagnosis and follow the time-course of pathological changes occurring in the skeleton during endocrine diseases.

Algorithms↗
PubMed1991

Computational methods for analyzing the structure of cancellous bone in planar sections.

Conventional stereologic methods for expressing the orientation of anisotropic materials are limited to materials assumed to possess orthogonal directions of orientation. In many substances, including cancellous bone, this assumption is unsubstantiated. Presented here are two simple methods for characterizing the orientation of any anisotropic material within a plane. By modeling the substance as a series of lines oriented in particular directions, it is possible to arrive at either a "phase distribution" that expresses the degree of orientation distributed over a range of angles or a series of "primary orientations" that express the degree of orientation at a select number of angles, with an additional measure of the degree of isotropy. This characterization of anisotropy is highly dependent on such parameters as feature size, sample size, test line spacing, and test line width. Given the careful selection of these parameters, the new methods provide simple measures of orientation, which may prove useful in testing Wolff's trajectorial theory of the relationship between mechanical stresses and the orientation of cancellous bone.

Animals↗
PubMed1979

[Tangential pendulum irradiation of the thoracic wall with co-60 during radiation therapy of surgically treated cancers of the breast: comparison of measurement and computation methods for irradiation planning (author's transl)].

The irradiation technique for tangential pendulum 60-Co-irradiation of the thoracic wall is described, and the possibility of a homogeneous irradiation of the thoracic region of interest by means of individual irradiation planning together with a careful, but practicable, technique of positioning and adjustment is shown. The radiation load to the lung can be kept on a moderate level. Phantom measurements with thermoluminescence probes, films and an ionization chamber have been performed for three typical forms of the thorax. Dose distributions thus obtained show a satisfying accordance with calculated values of the dose, the deviations amounting to 3 to 8%. The EDP program applied, COMRAD, thus permits computation of individual pendulum isodoses with sufficient accuracy in practice, and therefore, may be used regularly.

Breast Neoplasms↗
PubMedDate not supplied

Estimating viral concentrations from dilution counts: a reliable computation method programmed on a pocket calculator.

A program for a Hewlett-Packard 41C calculator is described, applying the maximum likelihood method for the estimation of the density of a suspension of infective particles when counts are available for a number of independent dilutions of the original suspension. An unbiased estimate for the variance of the density, a suitable confidence interval and its corresponding confidence level are also given by the program. Moreover, after testing for the presence of overcrowding and/or clumping, the selection of suitable dilutions is fully automated so as to avoid recourse to statistical tables.

Computers↗
PubMedDate not supplied

[The role of computer methods in the diagnosis of mono- and multifactorial traumatic compression of the brain].

A scheme of differential diagnosis of mono- and multifactor compression of the brain was formed on the grounds of 18 most frequently encountered signs of the injury. The work is based on 693 cases which were verified on operation. The results were checked on a large independent selection. Accuracy of recognition was 87.5%. The Table suggested by the authors may prove valuable in emergency situations when the patients are admitted in a serious condition, in impetuous development of the compression syndrome, and when there is lack of time for carrying out instrumental examination.

Adult↗
PubMed1990

Computational methods for determining protein structures from NMR data.

The general procedures by which solution structures of proteins may be deduced from distance and angular constraints derived from NMR are reviewed, with an emphasis on practical aspects of the calculations. In addition, novel methods based on chemical shift calculations and on quantitative fits to nuclear Overhauser effect intensities are presented; these should provide improved understanding of the limits of our ability to simulate complex spectra, and may permit higher precision structures to be determined.

Macromolecular Substances↗