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Biomedical subjects

J Shannon

Publications and source records attributed to J Shannon.

46 records · Page 3Linked to original sources

Thoracic outlet syndrome: a comprehensive evaluation.

Using various modalities, 480 patients were evaluated for thoracic outlet compression syndrome. Of this group, 300 patients were eventually diagnosed as having thoracic outlet syndrome after extensive evaluation. Ninety of these patients underwent a total of 103 operative procedures for thoracic outlet decompression. Nerve conduction velocities and directional Doppler studies were the most useful adjuncts in making the diagnosis. Surgical therapy after proper selection yielded an 80.6 per cent long-term "good" operative result and an additional 6.9 per cent long-term "fair" operative result in follow-up to 12 years.

Adult↗

Intraoperative autologous transfusion during major aortic reconstructive procedures.

To evaluate the benefits and disadvantages of autologous intraoperative transfusion during major aortic reconstructive procedures, we retrospectively studied 50 patients who had major aortic revascularization procedures without the use of autologous transfusion devices (group 1) and prospectively evaluated a second 50-patient cohort having similar procedures, but with the use of the autologous transfusion device for salvaging and reinfusing lost blood. Both groups were assessed for preoperative risk factors and postoperative complications. We found a somewhat lower morbidity in the autotransfusion group and more complete replacement of blood loss. Autologous transfusion accounted for approximately 75% of all transfused blood in group 2, tremendously reducing blood bank requirements. In addition to reduction of immediate postoperative morbidity, further risks associated with homologous transfusion such as hemolysis, posttransfusion hepatitis, transfusion-related acute lung injury, anaphylaxis, and transfusion-transmitted acquired immunodeficiency syndrome (AIDS) were markedly reduced or eliminated.

Aged↗

Isolation of amyloplasts from developing maize endosperm.

Methods for the formation of protoplasts from developing maize endosperm and for the aqueous isolation of intact amyloplasts from such protoplasts are described. Protoplasts were obtained after incubating endosperm slices in a medium containing cellulase and pectolyase for 5 days at 4 degrees C or 5 hours at 30 degrees C. After purification in a Ficoll density gradient, the protoplasts were reptured by forcing the suspension through a Nitex mesh (20 micrometer) positioned at the lower end of a modified disposable syringe. The resulting filtrate was layered on a discontinuous Ficoll density gradient of 30, 15, and 10%. Each Ficoll solution contained 0.7 molar sucrose, 10 millimolar arginine, 10 millimolar dl-dithiothreitol, 50 millimolar 2-(N-morpholino)ethanesulfonic acid (pH 5.6), and 2 millimolar CaCl(2). After 3 hours in the cold, an amyloplast fraction 50 to 93% intact and free from cytoplasmic, mitochondrial, and glyoxysomal contamination was recovered in the 15% Ficoll layer. Amyloplast intactness was estimated by fluorescent microscopy and activity of certain amyloplast marker enzymes before and after rupture of the amyloplast membrane. Starch branching enzyme, ADPG-pyrophosphorylase, and nitrite reductase were used as amyloplast marker enzymes.

Journal Article↗

Malaria in southeast Queensland in 1979.

The incidence of malaria in Australia is increasing. With the emergence of strains of Plasmodium falciparum resistant to chloroquine there are new lessons to be learned by laboratory workers in the species diagnosis; by clinicians in the clinical manifestations, the treatment of prophylaxis; and by members of the public about the dangers of malaria, and how it can be prevented. At the same time, old knowledge must not be forgotten. This paper reports some recent experience with a sizeable number of cases.

Adolescent↗

Atherosclerotic coarctation of the abdominal aorta in women.

In the ten year interval from 1967 to 1976, in a group of 200 patients with aortoiliac occlusive disease, six were identified who presented a unique combination of physical findings, angiographic abnormalities and pathologic changes. Atherosclerotic coarctation describes this entity because of the discreteness of the lesion found, the extent to which the aorta is occluded and the presence of extensive collaterals. Pathologically, the lesion is an organized thrombus forming on a single ulcerated plaque in an aorta with a lumen that is otherwise well preserved. Distally, infantile vessels are found. Other features have been the absence of diabetes mellitus and the fact that all of these patients have been women. All but one patient smoked cigarettes. Local endarterectomy restored pedal pulses and provided lasting relief of symptoms in all of the patients.

Aged↗

Development of a surveillance program for occupational pesticide poisoning: lessons learned and future directions.

The authors describe the growth from 1987 through 1996 of the Occupational Pesticide Poisoning Surveillance Program at the Texas Department of Health. The program was initially based on a Sentinel Event Notification System for Occupational Risks (SENSOR) model, using sentinel providers to report cases, supplementing the passive reporting by physicians that was required by law. The model was evaluated after five years, and significant changes were implemented to improve case ascertainment. Current active surveillance methods emphasize collaboration with a number of agencies and organizations for identification of cases and follow-up. The number of confirmed occupational cases increased from 9 workers in 1987 to 99 workers in 1996. The evolution from a passive system to an active surveillance program expanded the number of reported cases and strengthened inter-agency collaborations.

Humans↗

Lateral femoral cutaneous nerve block revisited. A nerve stimulator technique.

BACKGROUND AND OBJECTIVES: Regional block of the lateral femoral cutaneous nerve (LFCN) often has disappointing success rates despite the large volumes of local anesthetic used. This study was undertaken to investigate the utility of using a nerve stimulator (NS) to localize and block the LFCN. METHODS: After obtaining institutional approval and informed consent, the authors proceeded with a two-stage study. In stage 1, 20 ASA 1 volunteers underwent LFCN block by both a fan and a NS technique in a prospective, randomized, crossover study utilizing strict criteria for success and extent of block. To predict clinical utility, 20 patients underwent LFCN block by the NS technique using the same assessment criteria (stage 2). Statistical analysis for the comparisons was completed employing the Fisher's exact or paired t-test as appropriate. P < .05 was considered significant. RESULTS: The NS technique significantly improved the success of LFCN block over the fan technique (100% vs. 40%, P = .00002). The extent of successful blocks was no different with the two techniques. Success in stage 2 was similar to that in stage 1 (85%) predicting clinical utility. CONCLUSIONS: A NS can be used to localize a purely sensory nerve; such as the LFCN, and improve success rates in regional anesthesia.

Adult↗