Search PubMed⌕ Search

Biomedical subjects

K Brown

Publications and source records attributed to K Brown.

At least 271 records · Page 15Linked to original sources
PubMed1995

Use of component analyses to identify active variables in treatment packages for children with feeding disorders.

We evaluated the separate components in treatment packages for food refusal of 4 young children. First, treatment packages were implemented until food acceptance improved. Next, a component analysis was conducted within a multielement or reversal design to identify the active components that facilitated food acceptance. The results indicated that escape extinction was always identified as an active variable when assessed; however, other variables, including positive reinforcement and noncontingent play, were also identified as active variables for 2 of the children. The results suggest that the component analysis was useful for identifying variables that affected food acceptance.

Child, Preschool↗
PubMed1995

Comparison of hard- and soft-copy digital chest images with different matrix sizes for managing coronary care unit patients.

OBJECTIVE: This study was to determine whether different digital display formats for portable chest radiographs of coronary care unit patients would provide comparable information for clinical care. In particular, we tried to ascertain whether 1024 x 1024 pixel (1K) images on a picture archiving and communication system (PACS) workstation would be comparable to 1760 x 2140 pixel (2K) images on workstations or to digital films. If comparability could be proved, we hypothesized that 1K workstations could considerably lower equipment and film costs and facilitate image transmission from point to point. MATERIALS AND METHODS: Four chest radiologists read a panel of chest studies assembled from 98 coronary care unit patients, comparing 1K and 2K soft-copy images with digital hard copies. For all three image types for the 98 patients, the readers evaluated nine image parameters that the cardiologists deemed essential for clinical decision making. Two other chest radiologists reviewed each patient's three image types, historical chest images, current and prior radiologic reports, and medical record to determine the consensus, or "truth findings." RESULTS: With one exception (small pleural effusions), the receiver operating characteristic analysis showed no significant differences in the clinical information derived from the three image types. CONCLUSION: For clinical management in a coronary care unit, comparable information can be obtained from digital radiologic chest studies using a 1K x 1K soft-copy format, a 2K x 2K soft-copy format, or a hard copy (film). Substantial savings in cost and time are therefore possible by using soft-copy images and lower resolution (1K x 1K) workstations and, when necessary, by transmitting images on regular telephone lines.

Coronary Care Units↗
PubMed1995

Effects of reduced exposure on computed radiography: comparison of nodule detection accuracy with conventional and asymmetric screen-film radiographs of a chest phantom.

OBJECTIVE: Radiographic exposure has been thought to have little impact on the diagnostic quality of chest computed radiography because of automatic digital control of global optical density. The objectives of this study were to compare images obtained with two different exposures in computed radiography with conventional and asymmetric screen-film images of the chest for the detection of simulated lung nodules by use of receiver operating characteristic analysis and to relate differences in observer performance to parameters of image noise measured for each receptor condition. MATERIALS AND METHODS: At 110 kVp (fixed), exposures for the two screen-film systems were those necessary to achieve adequate optical densities over the lung and mediastinal regions of an anthropomorphic phantom. The two exposures used for the computed radiographs corresponded to the exposure used for the conventional chest screen-film system and an exposure 22% lower. An anthropomorphic phantom constructed of materials matched to the muscle, lung, and bone attenuation of a muscular adult man was used. Soft-tissue-equivalent plastic nodules of various sizes were secured at multiple sites on the phantom to simulate lung nodules. The chest phantom was imaged in 50 configurations with a total of 70 superimposed nodules. The perceptual performances of five radiologists were compared by use of receiver operating characteristic analysis. The signal-to-noise ratio in the mediastinum and the coefficient of variation of noise were measured for all four image conditions by use of a step wedge technique to provide an explanation for differences in diagnostic accuracy. RESULTS: We found no significant differences in the detection of lung nodules between the two screen-film systems or between the conventional screen-film images and the standard-exposure computed radiographs. However, there was a significant decrease in nodule detection on computed radiographs obtained at a reduced exposure; this result was associated with a 21% decrease in the signal-to-noise ratio. CONCLUSION: Our results show that underexposure of computed radiographs decreases the detection of low-contrast objects such as lung nodules. Although consistent global optical density on computed radiographs is achieved over a wide range of exposures, the alterations in signal-to-noise ratio that result from underexposure can reduce the diagnostic quality of computed radiographs.

Adult↗
PubMed1995

Pulmonary thromboembolism: spectrum of findings on CT.

CT has emerged as a potentially important diagnostic technique in pulmonary thromboembolism that can provide direct visualization of the obstructing embolus and its associated vascular and pleuroparenchymal sequelae. Although the role of contrast-enhanced CT in the diagnostic algorithm of pulmonary embolism has not been defined, patients at risk for pulmonary embolism frequently undergo thoracic CT as part of the assessment for other cardiopulmonary conditions. As such, CT may provide the first indication of clinically significant pulmonary embolic disease. This essay reviews the vascular, pleural, and parenchymal features of pulmonary thromboembolism observed on CT scans, describes the limitations of CT, and discusses the imaging features of pulmonary embolism that overlap other clinical conditions.

Adult↗
PubMed1995

Reasoning and the art of therapy for spinal cord injury.

In this pilot study, qualitative methodology was used to examine the clinical reasoning of four experienced occupational therapists as they presented and modified therapeutic activities to treat patients with spinal cord injuries. The therapists demonstrated the multi-layered thinking discovered in previous research, but hierarchical structuring of knowledge emerged as an unexpectedly dominant theme in their reasoning. Examples of hierarchical thinking about therapeutic activity included creating mental files of therapy tasks and materials sequenced from elementary to advanced and determining the level of difficulty at which to present an activity in order to build the patient's skills in a stepwise manner. The therapists reported that they learned to make decisions about the use of activities in treatment by observing skilled clinicians and by treating patients.

Activities of Daily Living↗
PubMed1995

General practice health checks of elderly people: a county-wide survey.

All general practices in Nottinghamshire were sent a questionnaire to examine the organisation and structure of their annual health checks for elderly people. The results indicated that 99% of responding practices offered checks, yet nearly one quarter estimated that under 50% of their elderly population actually had a check. Many practices had no system for following up old people who did not respond to an invitation for a check. Practices with smaller numbers of elderly people were more likely to estimate high response rates to invitations for a check and more likely to follow-up those who did not respond. The findings are discussed in relation to the reasons why many elderly people do not receive their annual health check.

Aged↗
PubMed1995

Cue-exposure to alcohol-associated stimuli reduces autonomic reactivity, but not craving and anxiety, in dependent drinkers.

A controlled trial was conducted of cue-exposure with dependent drinkers in treatment. All subjects were engaged in an insight-oriented therapy programme, and responses to an alcohol-associated, compared with a neutral, stimulus were assessed at the beginning and end of treatment. Compared with a control group, which did not receive intervening cue-exposure sessions, subjects who received such interventions manifested reductions in heart rate, salivation and arousal responses to the alcohol-associated, compared with the neutral, stimulus. They did not, however, show similar reductions in subjective estimates of craving and anxiety. These results and the desynchrony in reductions in cue-reactivity across response domains are discussed in terms of their implications for cue-exposure in treatment and recent theorectical conceptualizations of the relationship between autonomic reactivity, craving and drinking behaviour.

Adult↗
PubMed1995

Familial acute myeloid leukemia and DiGuglielmo syndrome.

A family is described in which two sisters developed acute myeloblastic leukemia (AML FAB M2) and erythroleukemia (FAB M6) at ages 60 and 53, 15 years apart. Their father was diagnosed as having chronic erythremic myelosis (DiGuglielmo syndrome) 24 years earlier at age 56. Cytogenetic analysis of bone marrow blasts in the patient with AML M2 revealed a complex hyperdiploid karyotype with clonal abnormalities -3, -5, del(5)(q13q23), -8, +i(8)(q10), -11, add(11) (q23), add(12)(p13), -13, +3mar. No environmental risk factors could be identified. Hematologic and cytogenetic analysis of all living first degree relatives of the affected persons revealed hematological abnormalities, but normal constitutional karyotypes of peripheral blood lymphocytes and no induction of cytogenetic abnormalities in folate deficient medium.

Aged↗
PubMed1994

Transgenic animals in toxicology.

Recent advances have been made in the characterization of a number of transgenic animal models. These animal models have provided a powerful toxicological tool for studying in vivo chemical effects and have increased our understanding of the role of specific genetic alterations as predisposing factors for chemical carcinogenesis. The goal of this symposium was to introduce the development of transgenic animals and the utilization of transgenics in toxicology research focusing on understanding tissue-specific mutation, chemical effects, and cancer. The production of transgenic animals, including gene insertions and gene knockouts, and the utilization of transgenic technology for studying multistage carcinogenesis and tumor suppressor genes are described. Data on the application and implications of transgenics as a genetic endpoint are also discussed. The use of transgenic animals in toxicology should improve our understanding of the role of specific genetic alterations in the carcinogenic process and lead to improved estimations of human health risks.

Animals↗
PubMed1994

Simulated microgravity does not alter epithelial cell adhesion to matrix and other molecules.

Microgravity has advantages for the cultivation of tissues with high fidelity; however, tissue formation requires cellular recognition and adhesion. We tested the hypothesis that simulated microgravity does not affect cell adhesion. Human colorectal carcinoma cells were cultured in the NASA Rotating Wall Vessel (RWV) under low shear stress with randomization of the gravity vector that simulates microgravity. After 6-7 days, cells were assayed for binding to various substrates and compared to cells grown in standard tissue culture flasks and static suspension cultures. The RWV cultures bound as well to basement membrane proteins and to CEA, an intercellular adhesion molecule, as control cultures did. Thus, microgravity does not alter epithelial cell adhesion and may be useful for tissue engineering.

Basement Membrane↗
PubMed1994

tau Regulation of microtubule-microtubule spacing and bundling.

Tau proteins are microtubule-associated proteins that promote microtubule polymerization in vitro and in vivo. They are a family of neuronal proteins with apparent molecular weights in the range 50,000-68,000 determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Recently, a new member of this family has been described and its cDNA has been cloned. It has an apparent molecular weight of 116,000 and has been called high-molecular-weight tau (HMW tau). All the tau proteins are encoded by a single gene, which undergoes complex alternative splicing. In the present study, we have cloned into the baculovirus a cDNA fully encoding HMW tau as well as a truncated cDNA encoding a protein beginning 13 amino acids in front of the tau microtubule-binding domain. HMW tau-recombinant-virus-infected Sf9 cells overexpressed HMW tau, which induced the polymerization of microtubules and the formation of long cellular processes similar to those induced by low-molecular-weight tau (LMW tau) overexpression. Process cross sections revealed a larger spacing (approximately 35 nm) between microtubules when induced by HMW tau than when induced by LMW tau (approximately 20 nm). The truncated construct also induces processes, where microtubules were packed far more closely together (approximately 10 nm). Although branching did not occur in processes induced by intact tau S, 10% of the processes induced by the truncated tau protein branched.

Animals↗
PubMed1994

Philadelphia-negative chronic myeloid leukaemia: detection by FISH of BCR-ABL fusion gene localized either to chromosome 9 or chromosome 22.

Dual-colour FISH has been used to study two patients with chronic myeloid leukaemia (CML) associated with a normal karyotype. Co-localization of signals from BCR and ABL cosmids was observed in interphase nuclei from both patients. In one patient, analysis of metaphase spreads showed that the 3' region of the ABL gene was deleted from one chromosome 9 and inserted into chromosome 22. In a second patient 5' BCR sequences were missing from one copy of chromosome 22, and co-localized with 3' ABL sequences on chromosome 9. These results demonstrate the molecular heterogeneity of Ph-negative CML. In addition, they illustrate the potential usefulness of dual-colour FISH on interphase nuclei for monitoring the response to treatment of patients with Ph-negative CML.

Blotting, Southern↗