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Biomedical subjects

W H Olson

Publications and source records attributed to W H Olson.

At least 37 records · Page 2Linked to original sources
PubMed1985

Pacemaker diagnostic diagrams.

Dual-chamber pacemakers interact with cardiac rhythms in complex ways. The resultant surface electrocardiograms (ECGs) are often very difficult to interpret. A simple and automatic diagnostic diagram is described that graphically illustrates pacemaker-heart interactions. Pacemaker operation is explained by a continuous series of lines and symbols that interconnect any sequence of paced and sensed events in both chambers. Fixed, programmable, and adaptive pacemaker timing intervals are all shown in a simple format. The pacemaker diagnostic diagram is plotted directly below the ECG to help users interpret the paced cardiac rhythm. The pacemaker diagnostic diagram is generated by software in a pacemaker programmer from: (1) telemetered real-time event markers; (2) fixed and programmable timing parameters (lower rate, AV interval, etc.); (3) pacemaker conditional logic. If this computer analysis of the telemetered event markers is not consistent with normal pacemaker operation, a specific error-message is printed. The pacemaker diagnostic diagram should be useful for instruction, pacemaker follow-up, and troubleshooting.

Arrhythmias, Cardiac↗
PubMed1983

A mechanism for the control of patch size in mammalian cell DNA excision repair.

The hypothesis is suggested that size of the region excised in repair of UV-induced damage in mammalian cell is determined by the occurrence at random of a recognition sequence which terminates this excision process. The statistics of first occurrence times for a specific nucleotide sequence in a random chain are derived and shown to lead to an approximately random distribution of sizes around the average. The heterogeneity in sizes arising from a model are shown not to conflict with existing measurements. A sequence of length three or four is sufficient to account for the measured average size.

Animals↗
PubMed1983

Electron microscopic comparison of the sequences of single-stranded genomes of mammalian parvoviruses by heteroduplex mapping.

The sequence homologies among the linear single-stranded genomes of several mammalian parvoviruses have been studied by electron microscopic analysis of the heteroduplexes produced by reannealing the complementary strands of their DNAs. The genomes of Kilham rat virus, H-1, minute virus of mice and LuIII, which are antigenically distinct non-defective parvoviruses, have considerable homology: about 70% of their sequences are conserved. The homologous regions map at similar locations in the left halves (from the 3' ends) of the genomes. No sequence homology, however, is observed between the DNAs of these nondefective parvoviruses and that of bovine parvovirus, another non-defective virus, or that of defective adenoassociated virus, nor between the genomes of bovine parvovirus and adenoassociated virus. This suggests that only very short, if any, homologous regions are present. From our results, we predict an evolutionary relationship among Kilham rat virus, H-1, minute virus of mice and LuIII. It is interesting to note that, although LuIII was originally isolated from a human cell line and is specific for human cells in vitro, its genome has sequences in common only with the rodent viruses Kilham rat virus, minute virus of mice and H-1, and not with the other two mammalian parvoviruses tested.

Base Sequence↗
PubMed1981

Primary mediastinal seminoma with 67Gallium total body scan: a case report.

We describe a case in which radionuclide scanning was used for staging and assessing treatment of a germinal neoplasm. Primary mediastinal seminoma is an ectopic manifestation of the not infrequent germinoma. Controversy surrounds the histogenesis of this tumor. Management may include surgery, radiation therapy, chemotherapy or any combination of these. Because of the rather marked radiosensitivity of the tumor the prognosis generally is favorable. The radio-gallium scan was helpful in guiding and following treatment.

Adult↗
PubMed1981

Compound action potential reconstructions and predicted fiber diameter distributions.

Electrophysiologic and anatomic studies on cat saphenous nerve were combined with CAP modelling and computer analysis. Myelinated nerve FD histograms were compiled from transverse section photomicrographs using various estimates of diameter, primarily those based on fiber cross-section area. The FD histogram and biophysical parameters were more important in the CAP reconstruction model than the SFAP parameters. The biophysical parameters were optimized to obtain best fits between recorded and reconstructed CAPs. Finally, the inverse of the CAP reconstruction model was used to predict FD histograms from optimized biophysical parameters and recorded CAP waveforms under carefully controlled experimental conditions. The results of these studies provide an empirical basis for relating volume conducted CAPs to the anatomic and physiologic characteristics of nerve fiber bundles. More accurate histologic methods and procedures for estimating biophysical parameters are needed before this approach to the inverse problem can be pursued further. The major advantage of estimating FD distributions rather than CV distributions is that the anatomic data are truly independent reference standards for evaluating the results.

Action Potentials↗
PubMed1978

Therapeutic trial of tilorone in ALS: lack of benefit in a double-blind, placebo-controlled study.

Sixteen patients with amyotrophic lateral sclerosis (ALS) participated in a double-blind, placebo-controlled study using tilorone hydrochloride, a drug active against a variety of DNA and RNA viruses in animals. On the basis of neurologic examination, pulmonary function studies, quantitative muscle examination, speech recording, and periodic filming of functional muscle strength, it was concluded that at a dose of 1 gm per week, tilorone did not alter the course of ALS.

Adult↗
PubMed1977

Positive (99mTc) diphosphonate and 67 Ga-citrate scans in ameloblastoma: case report.

Technetium-99m-diphosphonate scintigrams and 67Ga citrate bone scans were performed in a patient with known ameloblastoma of the right mandible. The tumor concentrated both radionuclides avidly. The lesion was larger on the gallium scans, presumably due to inflammation of adjacent soft tissue and to poorer instrument resolution for 67Ga than for technitium. If a single radionuclide is to be selected for evaluating the extent of tumor in ameloblastoma, the bone-imaging agent is preferable.

Adult↗
PubMed1976

Imipramine-serotonin induced myopathy.

Imipramine and serotonin (5-HT) were used to produce a myopathy in rats. Imipramine was used to stimulate a defect in transport of 5-HT observed in the platelets of Duchenne's dystrophy patients. The most effective dosage schedule was imipramine, 10 mg per kilogram, for 7 days followed by 5-HT, 100 mg per kilogram, 6 hours after the final imipramine dose. A single series of injections produced focal groups of necrotic and regenerating muscle fibers. In some rats, multiple series of injections resulted in a chronic myopathy with a predilection for proximal muscles, particularly quadriceps. In addition to skeletal muscle lesions, focal areas of myocardial damage were seen. The affected rats had a marked elevation of plasma creatine phosphokinase (including MB isoenzyme), serum glutamic oxaloacetic transaminase, and lactic dehydrogenase. Femoral nerve section did not affect the development of muscle lesions.

Animals↗
PubMed1975

An improved method for examination of cerebrospinal fluid cells.

A new collection technique allows cytologic examination up to 2 weeks after lumbar puncture without loss of cells or morphologic detail. Cerebrospinal fluid (CSF) was allowed to flow directly from a lumbar puncture needle into a solution of Carbowax in ethanol and was then processed with a cytocentrifuge. Two groups of patients were studied -- those undergoing spinal anesthesia and those having myelography for low back pain. Lymphocytes, polymorphonuclear neutrophils, and ependymal cells were regularly found in the CSF; a definite difference was found in the quantity and cell types in the two patient populations. The proposed method may be sensitive enough to aid in the identification of other neurologic diseases with low cell counts.

Adult↗