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PubMed1986

Spinal computed tomography and computed tomographic metrizamide myelography in the early diagnosis of metastatic disease.

New lesions were shown by Tc99m bone scans to have developed in sixty patients with known metastatic cancer or high-risk primary cancer and normal neurologic examinations; they were further evaluated with plain radiographs, spinal computed tomography (CT), and CT myelography (CT-M) according to an algorithm. Three groups were identified based on plain radiographs: group 1 (normal radiograph), group 2 (compression fracture as indicated by radiograph), group 3 (evidence of metastasis as indicated by radiograph). In group 1 (n = 18), spinal CT revealed that 33% of the patients had benign disease and 67%, metastases; epidural compression was seen in 25% of the patients with metastasis as indicated by CT-M. In group 2 (n = 26), CT-M disclosed that 38% had a benign compression fracture and 62% had metastases and that 63% of the patients with metastases had an epidural compression. In group 3 (n = 16), spinal CT revealed that 15 patients had metastases (one patient had benign disease). Epidural cord compression was seen in 47% of the patients with metastatic disease. In all groups, the presence of cortical bone discontinuity around the neural canal (seen in 31 patients) was highly associated with epidural compression (seen in 20 patients). Our approach allowed the early and accurate diagnosis of spinal metastasis and epidural tumor as well as the diagnosis of benign disease and was useful in planning optimal local therapy.

Bone and Bones↗
PubMed1989

[A modified unit for detecting sleep apnea].

A comprehensive diagnostic work-up of patients with a suspected sleep apnea syndrome must include conventional polysomnographic monitoring during the night. On account of the considerable staff and technical requirement, however, this definitive diagnostic measure is not suitable for use as a screening programme. For this reason we undertook to develop a device for the computer-aided recording of sleep apnea. The heart of the unit is a 65816 microprocessor with an address capacity of 16 Mbytes. The oro-nasal airflow is recorded with the aid of thermistors, and, after digital filtering, the respiratory rate is continuously recorded on the basis of this signal. Continuous recording of the heart rate and oxygen saturation, is also effected, the recorded data being stored in the microprocessor. On conclusion of the data acquisition phase, evaluation and a compressed display is shown on any conventional personal computer. Our preliminary experience reveals that the algorithm employed is extremely reliable for the detection of respiration rate and apnea, even in the presence of unfavourable signal forms. Clinically relevant deviations from manual evaluation do not occur. As was to be expected, processing of the signals for heart rate and oxygen saturation presented no problems.

Humans↗
PubMed1992

Natural sequence code representations for compression and rapid searching of human-genome style databases.

Numeric descriptions ('bio-informatic descriptions') of amino acid residues have been developed which will be of value whenever the quality and quantity of information in very large (i.e. 'human genome style') gene and protein sequences is to be compared or manipulated. These codes are as natural as possible by our criteria (the same principles could be used in revision of the criteria). In particular, in storing and searching large amounts of sequence data, natural codes--which relate to the properties of amino acids--can be combined with existing fast-search algorithms but introduce several advantages. The code can be assigned such that sub-selection of bits leads to compressed databases with residues defined less specifically, by classes of properties. The most compressed representation leads to the specification of a residue as polar or non-polar, while the most extended representation used at present also allows specification of, for example, glyco-asparagine and phosphoserine. Preliminary studies on both a supercomputer and smaller machines suggest a 'worst-case' speeding of approximately 4.5-fold. For more intelligent searching, coding extensions mixed with the basic sequence data give the sequence data some of the character of a computer program.

Amino Acid Sequence↗
PubMed1990

Abdominal wall pain: an alternative diagnosis.

The cause of abdominal pain need not necessarily reside in the viscera; the abdominal wall is another source of symptoms. Some causes of abdominal wall pain are obvious, e.g. hernias, but not so others such as nerve entrapment syndromes. This review is concerned with causes of abdominal wall pain which, although common, may be easily overlooked.

Abdominal Muscles↗
PubMed1990

Image analysis techniques for automatic evaluation of two-dimensional electrophoresis.

Techniques for automatic analysis of two-dimensional electrophoresis gels by computer-aided image analysis are described. Original gels or photographic films are scanned using a laser scanner and the files are transferred to a microcomputer. The program package first performs a compression and preevaluation of the files. Spot identification and quantification is performed by the chain code algorithm after appropriate zooming and cutting. Labeling facilitates spot identification and quantification in numerical and graphical (pseudocolor) representation on peripheral devices for camera ready output. Interpolation between measured basepoints is performed by cubic spline algorithms which are automatically switched on and off, depending on the need by the program. High speed analysis and graphic representation is achieved using fast Assembler language routines rather than high level languages. One-dimensional gels can be analyzed using the same software. Spot matching between parallel two-dimensional gels has not yet been implemented.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2025

Approximating edit distances between complex tandem repeats efficiently.

MOTIVATION: Extended tandem repeats (TRs) have been associated with 60 or more diseases over the past 30 years. Although most TRs have single repeat units (or motifs), complex TRs with different units have recently been correlated with some brain disorders. Of note, a population-scale analysis shows that complex TRs at one locus can be divergent, and different units are often expanded between individuals. To understand the evolution of high TR diversity, it is informative to visualize a phylogenetic tree. To do this, we need to measure the edit distance between pairs of complex TRs by considering duplication and contraction of units created by replication slippage. However, traditional rigorous algorithms for this purpose are computationally expensive. RESULTS: We here propose an efficient heuristic algorithm to estimate the edit distance with duplication and contraction of units (EDDC, for short). We select a set of frequent units that occur in given complex TRs, encode each unit as a single symbol, compress a TR into an optimal series of unit symbols that partially matches the original TR with the minimum Levenshtein distance, and estimate the EDDC between a pair of complex TRs from their compressed forms. Using substantial synthetic benchmark datasets, we demonstrate that the estimated EDDC is highly correlated with the accurate EDDC, with a Pearson correlation coefficient of >0.983, while the heuristic algorithm achieves orders of magnitude performance speedup. AVAILABILITY AND IMPLEMENTATION: The software program hEDDC that implements the proposed algorithm is available at https://github.com/Ricky-pon/hEDDC (DOI: 10.5281/zenodo.14732958).

Algorithms↗
PubMed1990

Vector quantization for compression of multichannel ECG.

We propose a scheme based on vector quantization (VQ) for the data-compression of multichannel ECG waveforms. N-channel ECG is first coded using m-AZTEC, a new, multichannel extension of the AZTEC algorithm. As in AZTEC, the waveform is approximated using only lines and slopes; however, in m-AZTEC, the N-channels are coded simultaneously into a sequence of N + 1 dimensional vectors, thus exploiting the correlation that exists across channels in the AZTEC duration-parameter. Classified vector quantization (CVQ) of the m-AZTEC output is next performed to exploit the correlation in the other AZTEC parameter, namely, the value-parameter. CVQ preserves the waveform morphology by treating the lines and slopes as two perceptually-distinct classes. Both m-AZTEC and CVQ provide data-compression and their performance improves as the number of channels increases. Moreover, the final output differs little from the AZTEC output and hence ought to enjoy the same acceptability.

Algorithms↗
PubMedDate not supplied

Radiological image compression using full-frame cosine transform with adaptive bit-allocation.

We report a new bit-allocation scheme based on the full-frame cosine transform for radiological image compression. The new technique differs from a previously reported method in its use of a two-dimensional bit-allocation table to encode the compression data. This allows for an improved treatment of high frequency components in the transform domain. Consequently, it has the capability of faithfully reproducing limited numbers of high-contrast sharp edges in the image. Previously reported artifacts, induced in the reconstructed image by sharp edges in the original, have been eliminated. Experiments with 10 radiological chest images show almost no perceivable degradation in the reconstructed image at compression ratios below 10:1. Image quality at a fixed compression ratio is, in every case, comparable or superior to results using the old method. Furthermore, the new algorithm lends itself to hardware implementations that are both simple and fast.

Algorithms↗
PubMedDate not supplied

The Pennsylvania Plan. An algorithm for the management of lumbar degenerative disc disease.

An algorithm for the sequential management of the patient with low-back pain has been formulated from evaluation of treatment outcomes. Patients presenting with back pain complaints and cauda equina syndrome are evaluated with immediate myelography. Without this complication, back pain patients are treated with 6 weeks of conservative therapy. Those who fail to respond are evaluated with progressively more complex techniques. When sciatica predominates, treatment may ultimately include laminectomy. When back pain predominates, medical and psychosocial appraisal are recommended. Some with normal medical and psychosocial evaluations may become candidates for spine fusion. The remaining are treated according to the findings of such appraisals. Rigorous screening is mandatory prior to any surgery.

Algorithms↗
PubMedDate not supplied

Information preserving image compression for archiving NMR images.

This paper presents a result on information preserving compression of NMR images for the archiving purpose. Both Lynch-Davisson coding and linear predictive coding have been studied. For NMR images of 256 x 256 x 12 resolution, the Lynch-Davisson coding with a block size of 64 as applied to prediction error sequences in the Gray code bit planes of each image gave an average compression ratio of 2.3:1 for 14 testing images. The predictive coding with a third order linear predictor and the Huffman encoding of the prediction error gave an average compression ratio of 3.1:1 for 54 images under test, while the maximum compression ratio achieved was 3.8:1. This result is one step further toward the improvement, albeit small, of the information preserving image compression for medical applications.

Algorithms↗
PubMed1986

Compression of nucleic acid and protein sequence data.

This paper describes the application of text compression methods to machine-readable files of nucleic acid and protein sequence data. Two main methods are used to reduce the storage requirements of such files, these being n-gram coding and run-length coding. A Pascal program combining both of these techniques resulted in a compression figure of 74.6% for the GenBank data-base and a program that used only n-gram coding gave a compression figure of 42.8% for the Protein Identification Resource database.

Algorithms↗
PubMedDate not supplied

Adaptive Fourier series modeling of time-varying evoked potentials: study of human somatosensory evoked response to etomidate anesthetic.

Evoked potentials (EPs) have traditionally been analyzed in time domain, with amplitude and latency of various signal components used in clinical interpretation. A new approach, called adaptive Fourier series modeling (FSM), is presented here. Dynamic changes in magnitudes of Fourier coefficients are analyzed for diagnostic purposes. In order to estimate the time-varying changes in the Fourier coefficients of noisy signals, a least mean-square filtering algorithm is applied. Results of computer simulations as well as experimental data are presented. Time-varying trends are presented in a new compressed evoked spectrum format. These techniques are applied to the study of alterations in human somatosensory EPs caused by the intravenous administration of etomidate during neurosurgical procedures. Amplitude increases of the order of 200-500% occurring within a time span of about 100 sec were captured. Due to its superior convergence properties, the adaptive FSM technique estimates more rapid changes in amplitude and latency than exponentially weighted averaging or moving window averaging schemes.

Computer Simulation↗
PubMed1991

Management of persistent or recurrent urinary incontinence after placement of artificial urinary sphincter.

A rational systematic approach is presented in the evaluation of 14 men with persistent or recurrent urinary incontinence after placement of the AMS800 artificial urinary sphincter. Mechanical malfunctions, including device leaks and control assembly malfunctions, may often be discovered with physical examination and radiographic evaluations. Nonmechanical malfunctions, such as cuff erosion, inadequate cuff compression and functional urethral atrophy, can be diagnosed with perfusion sphincterometry, urethroscopy and a filling cystometrogram, all combined in 1 simplified technique. With the presented algorithm the over-all success rate after 1 revision was 82%. Mechanical malfunctions appear to have a better revision rate of success than nonmechanical malfunctions (100% versus 71.5%, respectively).

Humans↗
PubMed1988

Heteronuclear NMR studies of cobalamins. 31P NMR observations of cobalamins bound to a haptocorrin from chicken serum.

A vitamin B12-binding protein (haptocorrin) from chicken serum has been purified to homogeneity by photodissociative affinity chromatography and characterized by gel electrophoresis and UV-visible spectrophotometry of its aquocobalamin, hydroxocobalamin, and cyanocobalamin complexes. The haptocorrin is a glycoprotein with a molecular mass of about 70 kDa and a protein moiety of about 40 kDa. 31P NMR resonances of the haptocorrin-cobalamin complexes are relatively broad singlets (with or without proton decoupling) shifted downfield by 0.7-1.0 ppm from the position of the free cobalamin resonances. From the line width data, the relaxation of the phosphorus nucleus is found to be dominated by chemical shift anisotropy with a very minor (13%) component from dipolar interaction with the two nearest neighbor protons. The rotational correlation time of the haptocorrin at 25 degrees C is estimated to be 85 ns and the activation energy for rotational correlation 3.9 +/- 0.3 kcal mol-1. The downfield shift of the 31P resonances of cobalamins upon binding to the haptocorrin cannot be due to hydrogen bonding phosphodiester moiety or displacement of the axial base by a group on the protein. Calculations also show that the downfield shift is very unlikely to be due to dipolar deshielding of the phosphorus nucleus by the ring current of an aromatic residue of the protein. It is concluded that the downfield shift of the 31P resonance must be due to sterically induced changes in phosphodiester conformation which may, or may not, involve steric compression of the axial Co-N bond.

Algorithms↗
PubMed1989

Modified Box-Cox transform for modulating the dynamic range of flow cytometry data.

We describe an algorithm, Vout = Integer ([2(12)-1/2(12 lambda)-1] V lambda in-1) + 1; lambda greater than 0 based upon Box-Cox transformations as an alternative to nonlinear electronic amplifiers to expand or compress high- or low-amplitude flow cytometer-derived signals. If the indexing parameter lambda less than 1, input channels in the high-amplitude input range are compressed in the output range as occurs when an electronic logarithmic amplifier is used. However, if lambda greater than 1, input channels in the low-amplitude input range are compressed in the output range as occurs when an electronic power amplifier is used. Our modified Box-Cox transform can be implemented either during data collection or off-line for the transformation of previously collected raw data. The transform is the equivalent of an infinite class of nonlinear amplifiers. As the transform is implemented in software, it does not suffer from many of the disadvantages of nonlinear electronic amplifiers.

Algorithms↗
PubMed1985

Real-time analysis of sperm motion using automatic video image digitization.

A methodology is described for automatic, real-time analysis of sperm movement characteristics. Video micrographic images of spermatozoa are digitized, compressed, and then analyzed using a Motion Analysis Corporation Expert Vision system. The system includes a VP-100 video processor, a video camera, and a Sun-2/120 minicomputer. Algorithms for detection of and discrimination among sperm are described, and desirable operating characteristics of the system are considered. Salient parameters which characterize the kinematics of sperm swimming trajectories are discussed.

Analog-Digital Conversion↗
PubMed1985

The frozen shoulder.

The clinical entity of frozen shoulder has been the subject of considerable controversy concerning pathogenesis and treatment. This is a review and interpretation of the literature against the background of my personal experience and a formulation of a treatment algorithm based on a practical synthesis of these sources. The separate stages of the disease are clearly definable and must be considered in prescribing treatment for the purpose of compressing the natural history and morbidity of this self-limited though disabling condition.

Diagnosis, Differential↗