Biomedical subjects

G L Meyers

Publications and source records attributed to G L Meyers.

5 recordsLinked to original sources

PubMed1996

A fatality from idiopathic anaphylaxis.

BACKGROUND: Idiopathic anaphylaxis by definition is a form of anaphylaxis where no identifiable stimulus can be found. In our series of over 350 patients with idiopathic anaphylaxis there have been no reported deaths. OBJECTIVE: To report the clinical course of the first fatality in our series from idiopathic anaphylaxis. METHODS: A patient was evaluated for idiopathic anaphylaxis and started on our previously published protocol of corticosteroids, sympathomimetics, and antihistamines. RESULTS: Despite following our protocol--which has been effective in decreasing the number of emergency room visits, hospitalizations, and intensive care unit admissions--controlling the disease, and placing a high percentage of patients into remission, the patient with idiopathic anaphylaxis died unexpectedly after experiencing symptoms similar to previous episodes of idiopathic anaphylaxis. CONCLUSION: This is the first reported fatality from idiopathic anaphylaxis in our extensive series.

Adult↗

PubMed1986

Experimental infection of infant rabbits with verotoxin-producing Escherichia coli.

To study the pathogenesis of diarrheal disease due to verotoxin (VT)-producing Escherichia coli, 3-day-old rabbits were inoculated intragastrically with live E. coli O157:H7 (high VT producer), E. coli O113:K75:H21 (low VT producer), or O157:H45 (VT negative) and were examined for clinical symptoms, bacterial colonization, presence of detectable free VT in the intestines, and histological changes. Diarrhea developed consistently with 10(8) bacteria of E. coli O157:H7 but was observed only infrequently with even a higher dose of E. coli O113:K75:H21. VT-negative strains failed to cause diarrhea under the same experimental conditions. E. coli O157:H7 was recovered from the colon of infected animals in a significantly higher concentration than from the small intestine, and the clinical symptoms correlated with the presence of detectable free VT in the colon. Histological changes were seen mainly in the mid- and distal colon; these changes were characterized by a vast increase in apoptosis in the surface epithelium, increased mitotic activity in the crypts, mucin depletion, and a mild to moderate infiltration of neutrophils in the lamina propria and epithelium. Multiple foci of attached bacteria were seen on the surface epithelium of the gut-associated lymphoid tissue, cecum, and colon. Bacteria were never seen in epithelial cells or the lamina propria. These mucosal abnormalities as well as clinical symptoms were reproduced in infant rabbits by the intragastric administration of VT alone. These results are consistent with the hypothesis that VT plays a major role in the pathogenesis of diarrhea caused by E. coli O157:H7 and other VT-producing E. coli.

Age Factors↗

PubMed1983

Digital processing of microradiographic and fluorochromic images from bone biopsy.

Bone biopsy is an essential technique for the diagnosis of metabolic bone disease and the skeletal response to remedial therapeutic maneuvers. Among many approaches in analyzing the biopsy specimen, the imaging technique offers the greatest potential. The objective of this paper is to describe the methodologies developed for digital processing of microradiographic and fluorochromic images from bone biopsy. This procedure requires a microscope with conventional and ultraviolet illuminations, a vidicon camera with three color filters, a general purpose image processing system with three image memories, a digital computer with some specially tailored software programs. A good specimen preparation from bone biopsy is a prerequisite in assuring the success of the method. The methodology for processing the microradiographs is based on a completely developed procedure of black and white image processing. Production run is in progress. The methodology for processing the fluorochromic images is based on true color imaging, although the procedure is still preliminary, early results obtained so far are promising.

Animals↗

PubMed1977

Changes in airway mast cells and histamine caused by antigen aerosol in allergic dogs.

We studied the effect of inhaled specific antigen on airflow resistance, histamine concentration, and mast cell numbers in airway tissues in allergic dogs. In each of six allergic dogs with open chests, inhalation of specific antigen aerosol (Ascaris suum) increased airflow resistance from 0.30+/-0.40 (mean+/-SE) to 2.8+/-0.41 cmH2O/1 per s (P less than 0.05); decreased mast cell number from 38.6+/-3.2 to 24.3+/-4.5 mast cells/mm2 (P less than 0.05); decreased histamine (per mg airway tissue) from 5.3+/-0.4 to 3.5+/-0.2 ng (P less than 0.05) in lobar bronchi 5-7 mm in diam; and released histamine into the blood perfusing the lung, control arterial plasma histamine; 2.8+/-0.64 ng/ml; antigen: 154+/-1.7 ng/ml (P less than 0.005). Specific antigen caused no significant changes in mast cells or histamine in bronchi 1-2 mm in diam. Control aerosols of nonspecific antigen or methacholine did not change levels of mast cells or histamine in airway tissues. These results suggest that experimental canine asthma involves local airway reactions with degranulation of mast cells and histamine release, as well as vagally mediated reflex bronchoconstriction.

Aerosols↗

PubMed1975

Histamine release during antigen inhalation in experimental asthma in dogs.

Histamine release after antigen inhalation was studied in 12 dogs sensitive to nematode antigens. In 19 experiments, histamine was detected in arterial plasma after antigen inhalation; its concentration was correlated with changes in airflow resistance of the respiratory system (Rrs) (per cent change above control equals 132.3 plus 250 log histamine concentration). Histamine was released from the lung and was not attributable to the concomitant hypoxia. In 6 dogs given aerosols of dilute antigen and in 4 dogs given aerosols of compound 48/80, Rrs increased significantly, but no histamine was detected. Histamine may have been released close to airway receptors, inducing bronchoconstriction, but in amounts undetectable in arterial plasma. In 6 dogs, administration of 48/80 caused partial depletion of histamine stores but prevented the response to antigen inhalation in only one of 6 dogs tested. The close correlation between arterial histamine concentration and Rrs, the qualitatively similar response to antigen and 48/80 aerosols, and the inhibition of the response to antigen when histamine was depleted completely from the lung tissues suggests that chemical mediators are critically important in antigen-induced airway reactions.

Aerosols↗