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Biomedical subjects

K Brown

Publications and source records attributed to K Brown.

At least 379 records · Page 21Linked to original sources
PubMed1990

Trauma in the workplace. An overview.

To attenuate the incidence of occupational deaths and injuries, which occur at a rate of approximately 25 deaths and 10,000 injuries daily, occupational health nurses must focus on injury control for the entire population of workers. Knowledge of the mechanics of injury and populations at risk for various types and severities of injuries is essential to developing injury prevention programs and appropriately responding to emergent injuries. The lack of a comprehensive and reliable surveillance method has been described as a major obstacle in evaluating the occupational injury problem, as well as measuring progress toward achievement of the 1990 Objectives in Occupational Safety and Health. Variations in the estimates have been attributed to different methodologies used in collecting surveillance data, including diverse definitions, inclusion criteria, and data sources. Lost workdays due to injuries reported for 1983 cost an estimated $33.4 billion in direct and indirect costs. Mining, construction, agriculture, and transportation are the most hazardous industries in terms of both fatalities and injuries. Activities appropriate for the occupational health nurse in preventing injury include retrospective analysis of injury patterns and costs, proactive inspection of the workplace for high risk factors, preplacement screening of workers, ergonomic analysis of jobs, evaluation of the type and use of personal protective equipment, provision of safety training, and collaboration with other agents of the firm in evaluating and designing injury reduction strategies and disaster plans.

Accidents, Occupational↗
PubMed1990

Radiologic considerations in the adult respiratory distress syndrome.

ARDS is the clinical consequence of acute lung injury that results in increased-permeability edema. Distinct pathophysiologic stages are reflected in the radiographic evolution of the syndrome. Diffuse microatelectasis, proteinaceous edema fluid, and multifocal in situ pulmonary vascular occlusions characterize the acute stages of injury and result in the appearance of diffuse consolidations and occasional pleural effusions on the radiograph. In the chronic organizing stage of ARDS, the physiologic consequences of subsiding edema and tissue repair may be reflected by a transition to stable interstitial patterns. There is a high frequency of complications related to the decreased compliance of the injured lung that lead to interstitial emphysema and other barotraumatic complications. Survivors of ARDS exhibit various degrees of physiologic impairment and radiographic abnormality that may improve during the first year after survival. The relations between various indices of the severity of ARDS and the ultimate outcome are emerging. Debate continues about the specificity of the chest radiograph in distinguishing increased-permeability edema from hydrostatic edema. In fact, interstitial patterns and pleural effusions are observed in both. Nonetheless, the chest radiograph is a pivotal tool for monitoring patients at risk of serious morbidity from nosocomial lung infection, barotrauma, and the complications accompanying the use of invasive devices. It is hoped that as we develop a more uniform consensus on the clinical definition of ARDS and begin to classify patients according to specific clinical or physiologic observations, chest radiographic observation will acquire greater diagnostic and prognostic significance in these critically ill patients.

Acute Disease↗
PubMed1990

Managing change.

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Humans↗
PubMed1990

Enhancing magnetic resonance images using water bags.

Fascial planes between tissues are separated by connective tissue, fat, and blood vessels. Magnetic resonance imaging displays surface anatomy and soft tissues. Our team has been successful in demonstrating brachial plexus nerves as a model of magnetic resonance anatomy. Radiologists have devised methods to increase the resolution of images by suppressing noise and increasing the sharpness of the image. We added water bags to a 0.3 tesla permanent magnet suppressing the noise and increasing the signal to image our patients. The images proved to be sharper.

Humans↗
PubMed1989

Activation of the c-Ha-ras-1 proto-oncogene by methylation in vitro with alpha-acetoxy-N-nitrosodimethylamine.

alpha-Acetoxy-N-nitrosodimethylamine, an activated derivative of the carcinogen N-nitrosodimethylamine, methylated in vitro a plasmid containing the human c-Ha-ras-1 proto-oncogene, resulting in the generation of a transforming oncogene, assayed by transfection into NIH 3T3 cells. The resulting transformed cells were tumorigenic and metastatic in immune-deprived mice. Further transfection using tumor DNA led to the formation of three secondary NIH 3T3 transformants. DNA from these secondary transformants contained human ras gene sequences. Two of the three secondary transformants contained G----A mutations at guanine 35 in codon 12, and the third secondary transformant retained the wild-type sequence at codons 12, and 61. For the latter, the activating mutation was not determined. These results demonstrate that a simple methylating agent can activate a normal human ras proto-oncogene to a transforming oncogene.

Animals↗
PubMed1989

Mediastinal germ cell tumor in a young woman.

Primary mediastinal germ cell malignancies are uncommon neoplasms, usually presenting in young men. We review a case of a primary mediastinal seminoma occurring in a 23-year-old woman. The differential diagnosis, work-up and therapy for these lesions is discussed with emphasis on the role of magnetic resonance imaging in the evaluation of anterior mediastinal masses.

Adult↗
PubMed1989

Evaluation of the flow-volume loop as an intra-operative monitor of respiratory mechanics in infants.

Airway pressure is currently the primary indicator of respiratory mechanics used by the anesthetist in the operating room. This quantity can signal that the mechanical properties of the respiratory system have changed. However, there is a need for more sophisticated monitors of mechanics, capable of indicating the nature of the change. We have investigated the use of the tidal flow-volume loop in differentiating between an obstruction of the endotracheal tube and changes in the distribution of regional ventilation, using a computer model. Endotracheal obstruction caused the descending limb of flow-volume loop to become convex to the volume axis, whereas ventilation inhomogeneity caused the curve to become concave to the volume axis. In contrast, examination of peak airway pressure did not allow differentiation between the two conditions. We conclude that, while the peak airway pressure is useful in signaling a change in a patient's condition, the combination of airway pressure and the flow-volume loop serves as a more comprehensive monitor of respiratory mechanics.

Computer Simulation↗
PubMed1989

Cognitive impairment, clinical course and treatment history in out-patients with bipolar affective disorder: relationship to tardive dyskinesia.

Clinical, neuropsychological and psychopharmacological characteristics were investigated for their ability to distinguish individuals with and without involuntary movements (tardive dyskinesia), among a population of 40 out-patients with bipolar affective disorder and a history of exposure to neuroleptics and lithium. Impaired performance on a test of cognitive flexibility bore the primary association with both the presence and the severity of involuntary movements. The additional relationships identified emphasized further that individual vulnerability to involuntary movements appeared to be associated not with greater duration or dosage of treatment, but with features of the bipolar illness, including number and type of affective episodes, for which that treatment was prescribed.

Adult↗
PubMed1989

Potential target sites for antiviral inhibitors of human immunodeficiency virus (HIV).

The rapid identification of anti-HIV compounds in the laboratory following the isolation of the causative virus in 1983 and their subsequent use in the clinic was not unexpected. Three decades of previous work had established a scientific basis for the evaluation of antiviral compounds. However, no antiviral yet discovered can cause total blockade of a virus replicating in a cell. The combination of properties of HIV including latency, antigenic and biochemical variation is unusual and the virus represents a daunting challenge for chemotherapy. But at least 90 antiviral compounds have been discovered, many inhibiting the virus reverse transcriptase. Other targets for inhibition are possible including viral regulatory gene products, viral protease and endonuclease enzymes but compounds for initial study will have to be found by random searching. X-ray crystallography of HIV proteins will shortly be possible, enabling the commencement of a more molecular specific search for inhibitors. Meanwhile, advantage can be taken of comparative nucleotide sequences of the HIV-1 and -2 genomes to test short oligonucleotides as potential inhibitors of mRNA transcription. The pol gene also has a zinc finger amino acid sequence suggesting that chelation chemotherapy may have a potential role. In the absence of HIV vaccines, and associated theoretical problems in their development, antiviral chemotherapy is expected to occupy a central role in combating the AIDS epidemic.

Antiviral Agents↗
PubMed1989

Chemical induction of oncogene mutations and growth factor activity in mouse skin carcinogenesis.

The goal of understanding the molecular basis of human tumor development has been greatly facilitated by the use of animal model systems in which the etiology of tumor development can be carefully controlled. Environmental chemicals, either naturally occurring or artificially produced, are thought to make a major contribution to the human tumor burden. Many of the concepts of multistage carcinogenesis have been developed and refined using the mouse skin model system and the work described in this article has been carried out in an attempt to analyze the molecular changes that are associated with the initiation of tumor development, the selection of initiated cells to form papillomas, or the progression of premalignant tumors to carcinoma. We have analyzed a number of skin tumors induced in mice by a two-stage initiation and promotion protocol and have detected a high frequency of c-ras oncogene mutations in this system. The mutation found in each case correlates well with the known reactivity of the carcinogens used. It has also been shown that where ras activation occurs this represents an early event in the tumor model system. Transforming growth factor beta is induced in mouse skin by tumor promoter treatment and may therefore play a role in the selection of initiated cells to form papillomas. Additional events, some of which involve the loss of normal ras alleles and possibly tumor suppressor genes, appear to take place at a later stage of carcinogenesis.

Animals↗
PubMed1989

Birth of the Probe.

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Journalism, Dental↗
PubMed1989

Nerves on magnetic resonance imaging.

Nerves are often visualized on magnetic resonance imaging (MRI) studies of the soft tissues on the chest and shoulder girdle. To learn the reasons for the contrast between the nerves and adjacent tissues, the authors obtained a fresh specimen containing part of the brachial plexus nerves from the left axilla and compared MRI with x-ray projections and photomicrographs of histologic sections. The results suggest that the high signals from the nerves stand out in contrast to the low signals from their rich vascular supply.

Connective Tissue↗
PubMed1989

Anatomy of the abdomen, back, and pelvis as displayed by magnetic resonance imaging: Part One.

In April 1986, magnetic resonance imaging (MRI) of the thorax and shoulder girdle was presented to the 99th Annual Meeting of the American Association of Anatomists. These images were the authors' first attempt to correlate the magnetic resonance display of the muscles and soft tissues of the chest in the coronal plane with surface gross anatomy. The original purpose of this study was to introduce the role of magnetic resonance imaging to anatomists, medical students, and the specialty of radiology. However, this approach has been expanded by imaging other sections of the body and applying the display of surface anatomy to augment the teaching of anatomy to surgical oncology, pathology, and kinesiology. This three-part article will display magnetic resonance images and will explain how magnetic imaging of the soft tissues can visually augment the teaching of gross anatomy without dissecting surface tissues.

Abdomen↗
PubMed1989

Anatomy of the abdomen, back, and pelvis as displayed by magnetic resonance imaging: Part Two.

In April 1986, magnetic resonance imaging (MRI) of the thorax and shoulder girdle was presented at the 99th Annual Meeting of the American Association of Anatomists. These images were the authors' first attempt to correlate the magnetic resonance display of the muscles and soft tissues of the chest in the coronal plane with surface gross anatomy. The original purpose of this study was to introduce the role of magnetic resonance imaging to anatomists, medical students, and the specialty of radiology. However, this approach has been expanded by imaging other sections of the body and applying the display of surface anatomy to augment the teaching of anatomy to surgical oncology, pathology, and kinesiology. This three-part article will display magnetic resonance images and will explain how magnetic imaging of the soft tissues can visually augment the teaching of gross anatomy without dissecting surface tissues.

Abdomen↗