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Biomedical subjects

R A Larsen

Publications and source records attributed to R A Larsen.

At least 73 records · Page 4Linked to original sources
PubMed1986

The epidemiology and risk factors for nosocomial catheter-associated bacteriuria caused by coagulase-negative staphylococci.

Studies of the risk factors for bacteriuria associated with the use of temporary indwelling urinary catheters have focused on gram-negative bacilli and enterococci, the predominant causes of nosocomial urinary tract infection. During a prospective study of 747 catheterized patients, bacteriuria with greater than or equal to 1,000 bacteria/mL were found in 96 patients. Coagulase-negative staphylococci (CNS) accounted for 19% of the episodes of bacteriuria, and S. epidermidis was the most frequent species of CNS. Significant risk factors for bacteriuria were a positive meatal culture for CNS, non-surgical illness, and no antibiotic therapy during catheterization. In contrast to the results of this and earlier studies that females were at greater risk factor for catheter-associated bacteriuria with gram-negative bacilli and enterococci, this was not a risk factor for acquisition of CNS. Possibly this is due to the more similar prevalence of meatal colonization with CNS of males and females compared to the striking difference in prevalence of meatal colonization with gram-negative bacilli and/or enterococci of males and females.

Adult↗
PubMed1986

The frequency of fungal involvement in abnormal vocal cord biopsy specimens.

Finding an unsuspected fungal infection of the true vocal cord prompted a retrospective study of abnormal vocal cords received as surgical specimens. Of 30 cases initially diagnosed histologically as either inflammation or hyperkeratosis, two (in addition to the index case) contained fungal elements visible on special stains. None of the patients had systemic mycoses on examination or on follow-up. Local excision apparently cured all lesions. Fungi may cause more vocal cord lesions than previously recognized and cannot be well visualized on routine sections.

Aged↗
PubMed1985

Development of a computerized infectious disease monitor (CIDM).

At the LDS Hospital in Salt Lake City, an interface was developed between the microbiology laboratory computer system and the HELP integrated central hospital computer system. The HELP system includes medical information from most clinical care support areas. The microbiology data are translated from the laboratory computer file structure to a hierarchical data structure on the HELP system. A knowledge base was created with the help of infectious disease experts, and became part of a Computerized Infectious Disease Monitoring system (CIDM). The knowledge base is automatically activated when specific microbiology data are entered into a patient's computer file (data driven), thus decisions are made automatically with no additional effort required of medical personnel. The CIDM was designed to inform infectious disease personnel when a patient has one of the following conditions: a hospital-acquired infection, an infection at a normally sterile body site, an infection due to a bacteria with an unusual antibiotic sensitivity pattern, an infection for which the patient is not receiving an antibiotic to which the offending bacteria is sensitive, an infection that could be treated with a less expensive antibiotic, an infection which is required by law to be reported to state and national health authorities, and those patients receiving prophylactic antibiotics longer than is medically indicated. All of the microbiology data are now extensively reviewed by nurses and physicians from terminals at nursing stations or intensive care units. The CIDM is currently being used for hospital-acquired infection surveillance at LDS Hospital.

Anti-Bacterial Agents↗
PubMed1985

Acute respiratory failure caused by primary pulmonary coccidioidomycosis. Two case reports and a review of the literature.

Acute respiratory failure caused by infection with Coccidioides immitis is a rare, usually fatal, event. We report 2 patients who survived acute respiratory failure caused by primary pulmonary coccidioidomycosis. We attribute the severity of illness to a large inoculum of organisms. Their treatment included antifungal therapy with amphotericin B and diuresis to decrease noncardiogenic pulmonary edema. Coccidioidomycosis causing respiratory failure may be more frequent than currently clinically appreciated and may result from primary pulmonary coccidioidomycosis, miliary pulmonary disease, or as part of the multisystem organ failure seen in fungemic patients.

Adult↗
PubMed1981

Preliminary criteria for clinical remission in rheumatoid arthritis.

A study was conducted to develop criteria for clinical remission in rheumatoid arthritis (RA). Data were provided by 35 rheumatologists on 175 RA patients considered to be in complete remission (with or without antirheumatic therapy) and 169 RA patients in partial remission or with active disease. Six criteria yielded optimal discrimination: morning stiffness absent or not exceeding 15 minutes, no fatigue, no joint pain by history, no joint tenderness, no joint or tendon sheath swelling, and no elevation of erythrocyte sedimentation rate. In this study sample, the presence of five or more of these criteria in an individual patient yielded 72% sensitivity for clinical remission and 100% specificity in discriminating RA patients with active disease. In a population sample, it is estimated that the overall accuracy of these criteria would be more than 90% in RA patients.

Adult↗
PubMed1977

Relative dipolar behavior of the equivalent T wave generator: quantitative comparison with ventricular excitation in the rabbit heart.

We studied the relative dipolar and nondipolar content of signal energy throughout ventricular excitation and recovery in 34 isolated, perfused rabbit hearts, suspended in an electrolyte-filled spherical chamber. Computer-processed signals were derived from 20 evenly spaced tank-surface electrodes, and a single, moving, equivalent cardiac dipole generator was optimally fitted to the recorded potentials for each 1-msec sampling interval. Superimposed, time-based plots of signal energy for the 34 preparations showed ventricular excitation to be strikingly more nondipolar than was recovery. In terms of the summed square ratio of nondipolar residual energies, overall nondipolarity of QRS exceed that of ST-T by 41%. Furthermore, the maximum instantaneous ratio during QRS was considerably greater than during the ST-T. Evaluation of paired differences, comparing nondipolar behavior throughout QRS with all of ST-T, proved highly significant (P less than .005). We also found that in contrast to the considerable mobility exhibited by the equivalent QRS dipole, the ST-T dipole locus remained nearly stationary during most of ventricular recovery. Presumably because repolarization is temporally and spatially a relatively diffuse process, it may generate electrical fields which are notably more dipolar than those caused by depolarization.

Animals↗
PubMed1975

Localization of heart vectors produced by epicardial burns and ectopic stimuli; validation of a dipole ranging method.

Location of the equivalent cardiac dipole has been estimated but not fully verified in several laboratories. To test the accuracy of such a procedure, injury vectors were produced in 14 isolated, perfused rabbit hearts by epicardial searing. Strongly dipolar excitation fronts were produced in 6 additional hearts by left ventricular pacing. Twenty computer-processed signals, derived from surface electrodes on a spherical electrolyte-filled tank containing the test preparation, were optimally fitted with a locatable cardiac dipole that accounted for over 99% of the root-mean-square surface potential. For the 14 burns (mean radius 5.0 mm), the S-T injury dipole was located 3.4 plus or minus 0.7 (SD) mm from the burn center. For the 6 paced hearts, the dipole early in the ectopic beat was located 3.7 mm (range 2.6 to 4.6 mm) from the stimulating electrode. Phase inhomogeneities within the chamber appeared to have a small but predictable effect on dipole site determination. The study demonstrates that equivalent dipole location can be determined with acceptable accuracy from potential measurements of the external cardiac field.

Animals↗