PubMed Health⌕ Search

Biomedical subjects

B Baxter

Publications and source records attributed to B Baxter.

At least 19 recordsLinked to original sources
PubMed1994

High doses of purified influenza A virus hemagglutinin significantly augment serum and nasal secretion antibody responses in healthy young adults.

The reactogenicity and immunogenicity of purified influenza virus hemagglutinin (HA) vaccines administered intramuscularly were evaluated in two placebo-controlled clinical trials. A total of 139 healthy young adults were randomized to receive increasing doses of monovalent influenza A/Taiwan/1/86 (H1N1) virus HA (range, 0 to 405 micrograms per dose [study 1]). An additional 139 subjects were given increasing doses of a trivalent HA vaccine containing equal amounts of A/H1N1 virus, A/Shanghai/16/89 (H3N2) virus, and influenza B/Yamagata/16/88 virus HA (range, 0 to 135 micrograms of HA per strain, 0 to 405 micrograms per dose) or a standard dose of commercial influenza vaccine (study 2). Increasing doses of HA were associated with increasing frequencies of symptoms at the vaccination site early after vaccination, but all doses were well tolerated. Occurrence of systemic symptoms was unrelated to dose. Increasing the dose of HA resulted in increasingly higher postimmunization levels of serum hemagglutination inhibiting and neutralizing antibody levels versus influenza A/H1N1 virus in study 1 (P < 0.05); these enhanced responses persisted for up to 6 months. Nasal secretory immunoglobulin A and G antibody responses were assessed 2 weeks after immunization with monovalent H1N1 virus HA; the frequencies of significant responses also increased in a dose-related fashion. Similar increases in serum antibody levels were noted for both A/H1N1 and A/H3N2 viruses in study 2. These data provide a basis for proceeding with the evaluation of high doses of purified HA in the elderly.

Adolescent↗
PubMed1991

Genotoxic and mutagenic effects of the diagnostic use of thallium-201 in nuclear medicine.

In order to investigate possible mutagenic effects of in vivo exposure to low levels of ionizing radiation used in nuclear medicine, we have examined the hypoxanthine guanine phosphoribosyl transferase (hprt) mutant fraction (MF) and chromosome aberration (CA) frequency in 24 nuclear medicine patients before and after injection of thallium-201. The mean MF of the thallium-201-exposed cohort was 5.2 +/- 4.4 x 10(-6) before injection exposure. No significant difference in MF was observed 24 h later. In 11 patients who were studied on a third occasion, 30 days after thallium-201 exposure, there was again no significant difference in post-exposure as compared with the pre-exposure MF. The frequency of CA in peripheral blood lymphocytes was not significantly different, comparing pre- and 24 h to 1 month post-radionuclide exposure. Thus, thallium-201 exposure was not associated with significant elevations in MF or CA frequency in lymphocytes of exposed individuals.

Chromosome Aberrations↗
PubMed1991

In vivo exposure of human lymphocytes to technetium-99m in nuclear medicine patients does not induce detectable genetic effects.

Recent reports have demonstrated that exposure of nuclear medicine patients to thallium-201 does not result in a detectable increase in mutation at the hprt locus in human lymphocytes. In an effort to study further the potential genetic effects of medical exposures to low dose radiation, we have examined chromosome aberrations and mutations in peripheral blood lymphocytes from nuclear medicine patients exposed to clinical doses of technetium-99m. Our results show that there is no exposure-related increase in chromosomal damage; furthermore, the data do not confirm earlier reports of exposure-related increases in mutations induced by technetium-99m.

Analysis of Variance↗
PubMed1985

The development of radiologic schemata through training and experience. A preliminary communication.

Research underway in our laboratory suggests that radiologists may develop a visual representation of a prototypical radiograph (a schema) in the course of clinical training. This schema appears to guide radiologists' interpretations of chest radiographs. Cognitive psychologists have demonstrated schematic processing for familiar events or scenes. In our experiments, experienced radiologists (18.5 years average experience), junior staff radiologists (3.5 years), and first-year radiology residents participated in a simple recognition/memory test of chest radiographs. The test phase followed a training phase in which each radiograph was viewed for 500 milliseconds. Both abnormal and normal chest radiographs were used. Correct responses were recorded during the test phase for measuring recognition memory. Residents showed no significant difference in memory between normal and abnormal films. Observers with greater radiologic experience exhibited poorer memory for normal films and better memory for abnormal films compared with less experienced observers. We hypothesize that the development of radiographic schemata as a result of experience accounts for these findings.

Cognition↗
PubMed1985

Digital separation of primary and scatter components of chest radiographs.

This article describes a technique for digital separation of the primary and scatter components of a radiographic image. The method involves mathematical modeling of the process whereby an antiscatter grid reduces scatter patterns in film radiographs. Two superimposable radiographs (one taken with and the other without an intervening antiscatter grid) are applied to the model. Performance characteristics of the grid (primary and scatter transmittance factors) are also determined and used in the model. Radiographs of a humanoid chest phantom are processed. Scatter/primary separation appears to be accurate to within 15%. Film images that are quantitatively faithful to the calculated primary and scatter fields are included.

Analog-Digital Conversion↗
PubMed1984

Lymphocyte subsets and urinary excretion of cytomegalovirus among homosexual men attending a clinic for sexually transmitted diseases.

A significantly higher frequency of urinary excretion of human cytomegalovirus (HCMV) was noted in homosexual men (29 [18%] of 161) than in heterosexual men (3 [4%] of 77) attending a clinic for sexually transmitted diseases. However, differences were not significant when only persons with antibody to HCMV were compared (29 of 157 vs. 3 of 33). The homosexual men who excreted HCMV had a significantly lower mean ratio of T-helper (OKT4+) to T-suppressor (OKT8+) cells (1.13 +/- 0.09) than did the homosexuals who did not excrete HCMV (1.67 +/- 0.1) or than did the heterosexual men (2.28 +/- 0.2). The abnormal ratio resulted from both a decrease in the percentage of OKT4+ and an increase in percentage of OKT8+ lymphocytes. The urinary excretion of HCMV by asymptomatic individuals who exhibit serological evidence of previous infection by this virus may be an indicator of impaired immune competence.

Adolescent↗
PubMed1982

Application of a three-dimensional display in diagnostic imaging.

An autostereoscopic viewing device for tomographic scans that allows a physician to examine multiple computed tomography sections with each section properly positioned in three dimensions has been constructed and tested. Images produced on the device allow the observer to utilize both motion parallax and stereoscopic depth cues as if viewing a real three-dimensional (3D) object. These 3D images can be very striking because of the ease with which one can form a true impression of depth relationships. We describe operating principles of the viewing device and the appearance of images produced on it. Stereo photographs made from 3D images displayed on the device are included to illustrate potential applications and problems.

Data Display↗
PubMed1974

Disposable drapes.

Explore the source record for details and available documents.

Disposable Equipment↗