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Biomedical subjects

B J Buchanan

Publications and source records attributed to B J Buchanan.

9 recordsLinked to original sources
PubMed1999

Pseudoephedrine and air travel-associated ear pain in children.

BACKGROUND: Young children often appear bothered by ear pain during ascent and descent while traveling on commercial airplanes. While pseudoephedrine hydrochloride is effective in decreasing the risk for earache in adults with recurrent air travel-associated ear pain, such use in children has not been studied. OBJECTIVE: To assess the efficacy and side effects of prophylactic pseudoephedrine in children traveling by air. DESIGN: A placebo-controlled, double-blind clinical trial. SUBJECTS AND METHODS: Children aged 6 months to 6 years were included in this study. Pseudoephedrine hydrochloride (1 mg/kg body weight) or placebo was administered 30 to 60 minutes prior to departure on commercial air flights. Caregivers noted historical details and the degree of apparent ear pain, drowsiness, and excitability with ascent and descent. RESULTS: Ninety-one flights involving 50 children were studied, with ear pain being reported in 13 (14%) of flights. Ear pain was not associated with a history of air travel-associated ear pain, recent ear infection, or recent upper airway symptoms. Pseudoephedrine use was not associated with a decrease in ear pain during either ascent (4% with pseudoephedrine vs 5% with placebo; P approximately 1.00) or descent (12% with pseudoephedrine vs. 13% with placebo; P approximately 1.00). Pseudoephedrine use was, however, linked to drowsiness at takeoff (60% with pseudoephedrine vs. 27% with placebo; P = .003) but not at landing (P = .39). Treatment was not associated with excitability at takeoff (P = .09) or landing (P approximately 1.00). CONCLUSIONS: Ear pain is not uncommon in children traveling by commercial aircraft. The predeparture use of pseudoephedrine does not decrease the risk for in-flight ear pain in children but is associated with drowsiness.

Aircraft↗
PubMed1977

Protection against endotoxin shock and impaired glucose homeostasis with ATP.

ATP-Mg++ (10 mumoles/100 g, iv) increased the LD50 for Salmonella enteritidis lipopolysaccharide (endotoxin) in male Holtzman rats (300 +/- 10 g) from 1.3 to 6.0 mg/rat. While endotoxin at 3 mg/rat iv 5 hr previously induced hypoglycemia to 12 +/- 4 mg/dl, ATP cotreatment blunted the hypoglycemia; i.e., plasma glucose values were 78 +/- 6 mg/dl. ATP treatment prevented the depression in gluconeogenesis induced by endotoxin as evaluated in vivo by the conversion of 14C-alanine to 14C-glucose. ATP treatment also reduced the hypercatabolism of U-14 C-glucose to 14CO2 in vivo and by epididymal fat pads in vitro. A role for ATP in preventing disruption of glucose homeostasis and development of endotoxin shock via counteracting insulin is suggested.

Adenosine Triphosphate↗
PubMed1976

Bioassay of endotoxin clearance in vivo and by perfused rat liver.

Endotoxin clearances in vivo and by the isolated perfused rat liver were evaluated via bioassay in lead-sensitized rats. A linear relationship between the probit of shock lethality and the endotoxin dose in the probit range of 4-6 was validated. Endotoxin clearance in normal, fed rats displayed a linear relationship between the logarithm of the blood endotoxin concentration and time throughout the period of 15-240 min at doses of 500 and 1,000 mug/ rat; the half-time values were 58-63 min. Decreasing the endotoxin dose to 250 mug resulted in multiphasic clearance curves. Induction of tolerance to endotoxin resulted in marked acceleration of endotoxin clearance. Endotoxin clearance from the isolated perfused rat liver was not influenced by serum or rat blood as compared to clearance from a balanced salt solution. These data suggest that a physiologically stressful dose of endotoxin is slowly cleared from the blood and, therefore, circulates for prolonged periods.

Animals↗
PubMed1976

Hypoglycemic depression of RES function.

The intravascular removal rates of colloidal carbon and of biologically active endotoxin by the reticuloendothelial system (RES) were evaluated as a function of blood-glucose levels. There was a significant negative correlation of carbon clearance half time on blood glucose in both saline-treated and insulin-treated rats. Insulin hypoglycemia depressed RES carbon clearance with the maximal effect occurring at blood glucose values below 30 mg/dl. Insulin hypoglycemia also severely impaired the intravascular removal of endotoxin as evaluated by lethality bioassay in lead-sensitized rats. It is concluded that blood glucose may modulate RES phagocytic function and that the hypoglycemia of endotoxin shock may augment the shock state due to impairment of RES host defense clearance functions.

Animals↗
PubMedDate not supplied

Elevated leg systolic pressures and arterial calcification in diabetic occlusive vascular disease.

Systolic occlusion leg and brachial pressures were determined using a Doppler ultrasonic method in 24 diabetic subjects with either past or evolving gangrene due to arterial occlusive disease of the lower extremities. The leg-brachial ratios were correlated with x-ray determined leg vascular calcification. Ratios above 1.10 were invariably associated with heavy continuous calcification of the tibial vessels; lesser degrees of arterial calcification had normal or depressed leg-brachial ratios. Medial calcification might be causally related to the abnormally elevated leg systolic pressures not infrequently noted in diabetic patients. Based on the observed occurrence of reamputation in association with normal or elevated leg-brachial ratios, it appears that a Doppler pressure index above 0.90 is not a reliable indicator of adequate blood flow in severe diabetic occlusive arterial disease.

Aged↗