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PubMed2005

Medicaid program; state allotments for payment of Medicare Part B premiums for qualifying individuals: federal fiscal year 2005. Interim final rule with comment period.

This interim final rule with comment period sets forth the methodology used to compute State allotments that are available to pay Medicare Part B premiums for qualifying individuals, allows changes to the State allotments and describes the methodology used to determine the changes to each State's allotment.

Health Care Rationing↗
PubMed1980

Determining the probability of an important difference in bioavailability.

Bioavailability studies usually compare formulations of a drug under the premise of equal bioavailabilities. Analyses of such studies may be questioned when large differences exist, but are not statistically significant, or when small differences are found which do reach statistical significance. In either case, the question of clinical significance is not addressed and remains problematic regardless of the outcome. The important question is, "Given the results of the study, what is the probability that a clinically important difference exists?" To obviate dependence on statistical significance, we propose a methodology which permits computation of the probability that a clinically important difference in bioavailability exists between two products, regardless of the results of conventional tests of hypothesis. The methodology permits a strong statement which defines the likelihood of a meaningful difference, rather than the "nonstatement" of current approaches. The approach is illustrated by a study in which a 2% (nonsignificant) difference in bioavailability was observed. Using the proposed methodology the analysis concluded that the odds are about 5 to 1 against there being a 20% difference in bioavailability between the formulations.

Bayes Theorem↗
PubMed2003

[Computed tomography in the diagnosis of inflammatory bowel disease -- methodology of MSCT and clinical results].

PURPOSE: This paper discusses the diagnostic yield of multislice computed tomography (MSCT) in inflammatory bowel disease. METHODS: Contrast media are administered intraluminally (colon, small intestine) and intravenously (triple contrast CT). Filling of small bowel is achieved by means of jejunal tube ("Sellink CT") or via the oral route. Pharmacological relaxation of the intestine decreases motion artifact. Intraluminal contrast media consist of either hyperdense, "positive" or hypodense, "negative" liquids. RESULTS: Thin-slice MSCT of the entire abdomen allows high-quality post processing (MPR, thin-slice MIP). Due to superior distension, Sellink CT improves estimation of stenosis or changes in thickness and contrast of bowel wall. Positive contrast is superior in the detection and preoperative localization of abscess, fistula or conglomerate tumour, because it accurately differentiates between intra- and extraluminal structures.However, negative contrast facilitates quantitative evaluation of bowel wall thickening or enhancement and demonstrates gastrointestinal bleeding. CONCLUSION: MSCT of the small intestine is superior to conventional enteroclysis, especially in the diagnosis of mesenterial or other extraintestinal disease. As a side effect, the colon is assessed in the same examination. Radiation dose is less in MSCT (7.8-13.3 mSv) than in conventional fluoroscopy (13.99+/-7.57 mSv). MSCT can be performed as an alternative or adjunct to colonoscopy, if endoscopic access is restricted. It is already the imaging modality of choice in acute diverticulitis.

Administration, Oral↗
PubMed1998

Improving morphology-based malignancy grading schemes in astrocytic tumors by means of computer-assisted techniques.

We propose an original methodology which improves the accuracy of the prognostic values associated with conventional morphologically-based classifications in supratentorial astrocytic tumors in the adult. This methodology may well help neuropathologists, who must determine the aggressiveness of astrocytic tumors on the basis of morphological criteria. The proposed methodology comprises two distinct steps, i.e. i) the production of descriptive quantitative variables (related to DNA ploidy level and morphonuclear aspects) by means of computer-assisted microscopy and ii) data analysis based on an artificial intelligence-related method, i.e. the decision tree approach. Three prognostic problems were considered on a series of 250 astrocytic tumors including 39 astrocytomas (AST), 47 anaplastic astrocytomas (ANA) and 164 glioblastomas (GBM) identified in accordance with the WHO classification. These three problems concern i) variations in the aggressiveness level of the high-grade tumors (ANA and GBM), ii) the detection of the aggressive as opposed to the less aggressive low-grade astrocytomas (AST), and iii) the detection of the aggressive as opposed to the less aggressive anaplastic astrocytomas (ANA). Our results show that the proposed computer-aided methodology improves conventional prognosis based on conventional morphologically-based classifications. In particular, this methodology enables some reference points to be established on the biological continuum according to the sequence AST-->ANA-->GBM.

Adult↗
PubMed1985

A new method for computing the macromolecular electric potential.

A general methodology is developed for the rigorous computation of the electrostatic potential for a protein of arbitrary shape, assuming the presence of linear dielectric media. The theory proceeds by considering the distribution of induced polarization charge at the dielectric interface, rather than by attempting a direct solution of Poisson's equation (as in the finite-difference approach of Warwicker & Watson). The method is applied to a study of two-dimensional model proteins, where it is shown that the presence of a cleft is associated with a region of relatively high potential in the solvent medium. The results of a preliminary calculation in three dimensions for the protein lysozyme are also discussed; again, a region of enhanced potential is observed near the cleft at the active site. Our computational evidence supports the suggestion of Warwicker & Watson that clefts are associated with important electrostatic effects.

Electricity↗
PubMed2006

Enzyme isoselective inhibitors: application to drug design.

Common methodologies of computer-assisted drug design focus on noncovalent enzyme-ligand interactions. We introduced enzyme isoselective inhibition trend analysis as a tool for the expert analysis of covalent reversible inhibitors. The methodology is applied to predict the binding affinities of a series of transition-state analogue inhibitors of medicinally important serine and cysteine hydrolases. These inhibitors are isoselective: they have identical noncovalent recognition fragments (RS) and different reactive chemical fragments (CS). Furthermore, it is possible to predict the binding affinities of a series of isoselective inhibitors toward a prototype enzyme and to extrapolate the data to a target medicinally important enzyme of the same family. Rational design of CS fragments followed by conventional RS optimization could be used as a novel approach to drug design.

Drug Design↗
PubMedDate not supplied

[Computer-controlled maintenance of the dissolved oxygen level in a medium during controlled cultivation of Neisseria meningitidis].

A new method for controlling the processes of N. meningitidis cultivation by the content of oxygen dissolved in the medium with the use of a computer, including the software, technical and methodological provision of the computer-operated control system, has been developed. The processes of the cultivation of N. meningitidis, groups A and B, under fully controlled conditions have been realized. The computer-operated control of the content of oxygen in the medium, the most important parameter of the process, has been shown to be essentially more effective than manual control. Information, accumulated in the course of the experiment, may be used in future for correction of mathematical models and optimization of the process. This will by necessary for obtaining biomass with predetermined properties in the development of new diagnostic and vaccine preparations.

Computers↗
PubMed1999

Group theory used to improve the efficiency of transfer-matrix computations.

Transfer-matrix methodology is frequently used to deal with elastic scattering problems that require a solution of Schrödinger or homogeneous Maxwell equations in the continuous part of their spectra. As predicted by group theory, the basic states used for the expansion of the solutions can be separated into independent sets, thus enabling the scattering problem to be solved with a drastically improved efficiency. Depending on the peculiar symmetry in the problem, the basic states can present pairs of "conjugate sets," whose associated characters are complex conjugate of each other. When the potential energy takes strict real values, the transfer matrices corresponding to these conjugate sets have well-defined relationships that enable the transfer matrices of both conjugate sets to be computed from a single propagation step. This results in a further reduction of up to 50% of the total computation time. This paper presents the way group theory can be used systematically to improve the efficiency of transfer-matrix computations. In a first part, the basic states are separated into independent sets. Relationships between the transfer matrices corresponding to conjugate sets are then derived. The theory is finally illustrated by a simulation of electronic scattering by a C60 molecule in a projection configuration.

Journal Article↗
PubMed1997

Computational neural networks for predictive microbiology: I. Methodology.

Artificial neural networks are mathematical tools inspired by what is known about the physical structure and mechanism of the biological cognition and learning. Neural networks have attracted considerable attention due to their efficacy to model wide spectrum of challenging problems. In this paper, we present one of the most popular networks, the backpropagation, and discuss its learning algorithm and analyze several issues necessary for designating optimal networks that can generalize after being trained on examples. As an application in the area of predictive microbiology, modeling of microorganism growth by neural networks will be presented in a second paper of this series.

Algorithms↗
PubMed1990

Medicinal chemistry: a support or a driving force in drug research?

The foregoing has demonstrated most emphatically the significant and central role which chemistry plays in modern and future drug research. It does not mean to diminish the important role of biology but it does serve to show that chemistry is not merely a support for the needs of biology but is a powerful driving force in itself. The two disciplines are essentially interdependent and each relies on the other for success in drug design, discovery and eventual delivery of a useful medicament to the patient. Finally, the medicinal chemist today is faced with as many if not more formidable challenges in medicinal research as his counterpart of a generation ago. The sciences of genetics, molecular biology, neuro-pharmacology and electrophysiology have expanded the knowledge base of cellular function many fold. This new knowledge when coupled with the fundamental role of biochemistry in outlining in chemical terms both normal and abnormal cellular events offers the researcher a much more sophisticated appreciation of the cause of disease states. Knowing which enzymes or receptors are involved is a crucial step towards correcting the malfunctioning cellular conditions. With powerful new methods for determining the three-dimensional structure of molecules and computer graphics which give insight on rational drug design and modification, the medicinal chemist can explore with greater confidence than ever before the road to new drugs. The new biology, the new physical methodology and the computer have enhanced the role of chemistry in modern drug research and have given the medicinal chemist a more profound grasp of cellular aberrations leading to disease. This knowledge is a golden rod in the hands of an imaginative chemist in the search of innovative drugs.

Biochemical Phenomena↗
PubMed2001

Human computers: the first pioneers of the information age.

Before computers were machines, they were people. They were men and women, young and old, well educated and common. They were the workers who convinced scientists that large-scale calculation had value. Long before Presper Eckert and John Mauchly built the ENIAC at the Moore School of Electronics, Philadelphia, or Maurice Wilkes designed the EDSAC for Manchester University, human computers had created the discipline of computation. They developed numerical methodologies and proved them on practical problems. These human computers were not savants or calculating geniuses. Some knew little more than basic arithmetic. A few were near equals of the scientists they served and, in a different time or place, might have become practicing scientists had they not been barred from a scientific career by their class, education, gender or ethnicity.

Computers↗
PubMed2001

Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography.

AIM: The aim of this study was to compare the effects of four preparation techniques on canal volume and surface area using three-dimensionally reconstructed root canals in extracted human maxillary molars. In addition, micro CT data was used to describe morphometric parameters related to the four preparation techniques. METHODOLOGY: A micro computed tomography scanner was used to analyse root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using Ni-Ti - K-Files, Lightspeed instruments, ProFile.04 and GT rotary instruments. Differences in dentine volume removed, canal straightening, the proportion of unchanged area and canal transportation were calculated using specially developed software. RESULTS: Instrumentation of canals increased volume and surface area. Prepared canals were significantly more rounded, had greater diameters and were straighter than unprepared canals. However, all instrumentation techniques left 35% or more of the canals' surface area unchanged. Whilst there were significant differences between the three canal types investigated, very few differences were found with respect to instrument types. CONCLUSIONS: Within the limitations of the micro CT system, there were few differences between the four canal instrumentation techniques used. By contrast, a strong impact of variations of canal anatomy was demonstrated. Further studies with 3D-techniques are required to fully understand the biomechanical aspects of root canal preparation.

Analysis of Variance↗
PubMedDate not supplied

A computer automated study of the structure-mutagenicity relationships of non-fused-ring nitroarenes and related compounds.

A quantitative structure-activity analysis of the mutagenicity of non-fused-ring nitroaromatic compounds is reported. The analysis is performed on the basis of substructural fragment descriptors according to a recently developed methodology acronymed CASE (computer automated structure evaluation). The compounds of the data base were reclassified as mutagens or nonmutagens n the basis of probabilistic considerations. The mutagenic potencies of these agents were calculated through a multivariate regression analysis using fragments as descriptors. A good correlation with experimental values is obtained.

Benzene Derivatives↗
PubMed1981

Computer quantitation of Q-T and terminal T wave (aT-eT) intervals during exercise: methodology and results in normal men.

Computer-quantitated measurements of the Q-T intervals, the Q-T/Q-Tc ratio (Q-T/corrected Q-T) and the terminal T wave (apex to end of T [aT-eT] interval) were evaluated in resting and exercise electrocardiograms of 130 normal men with a mean age of 40 years. Pseudo-orthogonal, bipolar X, Y and Z axis leads were recorded during treadmill exercise testing, and 25 consecutive QRS-T complexes from standing rest and three exercise stages were computer-averaged. The Q-T intervals, Q-T/Q-Tc ratio and aT-eT interval measurements were then computed in the X and Z axis leads only, because the Y lead proved to be too noisy for accurate interpretation. A correlation coefficient of 0.9830 resulted between measurements made manually from the plotted, composite QRS-T complexes and those made by computer. No significant differences , in the paired sense, were found between any of the measurements. Measurements made on the Z axis lead; however, the differences in the measurements remained constant across all stages of exercise. A Q-T/Q-Tc ratio of greater than 1.08, previously reported to be a reliable indicator of coronary disease, was observed in the majority of our normal subjects during exercise. Although the Q-T interval is substantially influenced by many factors, the aT-eT interval proved not to be age- or heart rate-dependent. It appears that the aT-eT interval can be measured with a high degree of reliability during exercise and it may prove to be a relatively specific indicator of repolarization alterations that occur with myocardial ischemia.

Adult↗
PubMed2001

GenePath: a computer program for genetic pathway discovery from mutant data.

The sequencing of the human genome and the genomes of several model organisms is the first step toward the long-term objective of genetic research: the identification of all genes, and the discovery of their functions and mutual interactions. This article presents a methodology and a computer program called GenePath to support the discovery of gene function. GenePath uses mutant data and available genetic knowledge to identify potential genetic pathways. Several pilot applications based on experimental results from Dictyostelium and C. elegans confirmed the usefulness of the proposed schema. Our results suggest that GenePath is a valuable tool that can be used as an intelligent assistant to support genetic reasoning.

Animals↗
PubMed1995

Computed tomographic images and three-dimensional expression of crystalline lens findings from multiple slices of Scheimpflug slit images.

Although the observation of lens changes in clinical examination has been made through a slit lamp microscope under dilated pupil, precise documentation and analysis of lens changes are presently possible through Scheimpflug photographic images. However, the methodology is still unsatisfactory because the image analysis is two dimensional. In order to overcome this disadvantage, the authors aimed at developing a new methodology for obtaining computed tomographic images of the lens. 60 Scheimpflug slit images of a cataractous human lens were taken by an anterior eye segment analysis system as digital data. After the locations of the whole slit images had been matched, reconstruction of the coronal section line images was performed utilizing extracted image information. The total number of reconstructed coronal section images in additional procedures of the image interpolation was 150. Computed tomography of the lens image was made from those 150 images. A whole lens figure was also demonstrated as a moving three dimensional image.

Aged↗
PubMed1997

Computer-assisted analysis of Mycobacterium avium fingerprints using insertion elements IS1245 and IS1311 in a Caribbean setting.

A total of 33 clinical isolates of the Mycobacterium avium complex from 25 patients, identified by means of biochemical and cultural characteristics, the Accuprobe system and DT1/DT6 PCR, were further analysed using novel insertion elements IS1245 and IS1311 in a French Caribbean setting. PvuII-cleaved DNA and non-radioactive Southern hybridization and detection systems were used for fingerprinting with both IS elements. The data confirmed the specificity of the two probes for M. avium in our setting and highlighted a significant proportion of M. intracellulare-infected patients in this region. Two distinct groups composed of 2-3 bands and 6-27 bands were found among M. avium isolates, and were composed of the same isolates both with IS1245 and IS1311. The computer analysis of polymorphic banding patterns identified two prevalent genotypes: one contained 4 isolates from 3 patients while a second 2-banded cluster was composed of 6 isolates from 4 patients; all the patients were from the same hospital in Guadeloupe. A single isolate from Martinique was falsely included in the 2-banded cluster initially upon IS1245 fingerprinting, but could be discriminated from other isolates on the basis of IS1311 fingerprinting of PvuII-cleaved DNA. These results were also confirmed upon IS1245 fingerprinting of PstI-digested DNA, as well as DT6 fingerprinting. A single case of polyclonal infection was also discovered in a patient at a 75-day interval. This is the first study comparing the two IS elements and constitutes a first description of disseminated M. avium complex disease from the Caribbean. We conclude that both elements possess a similar discriminatory potential for M. avium isolates. Coupled with computer analysis, this methodology would appear to be particularly suitable for larger epidemiological studies.

Acquired Immunodeficiency Syndrome↗