Biomedical subjects

B Bailey

Publications and source records attributed to B Bailey.

At least 73 records · Page 4Linked to original sources

PubMed1991

Stress-induced gastric lesions and the synthesis of prostaglandins and leukotrienes.

Prostaglandin E2 renders the mucosa of the GI tract more resistant to acute injury by aspirin, acid, bile salts, and stress, whereas leukotrienes promote inflammation and retard healing of ulcers. The relationship of stress ulcer formation to changes in the activities of prostaglandin synthetase and lipoxygenase was evaluated in this study. After a 24 hr fast, 10 rats were stressed by the cold-restraint method for 4 hr and 10 rats were not stressed. Rats were terminated, stomachs were excised, the number of lesions were counted, and the nonulcerated mucosa was assayed for prostaglandin E2 and leukotriene synthesis. The mucosa was minced, washed in buffered saline, and then incubated for 10 min in a 1.3 mM sodium arachidonate solution containing a nonionic detergent (poloxamer 188), NaCl, KCl, KPO4, glutathione, hemin, MgSO4 and Hepes at pH 8.0. An ANOVA was used to compare the groups. Following stress the number of gastric lesions increased from 0.7 +/- 0.6 to 13.5 +/- 2.6, while leukotriene synthesis increased from 173 +/- 20 to 2170 +/- 187 pg/mg/min. A shift in synthesis from prostaglandins to leukotrienes in the mucosa appears to be detrimental to cytoprotection.

Animals↗

PubMed1991

Phrenic nerve injury. A prospective study.

In cardiac surgery, topical iced saline solution slush has become an important adjunct in maintaining myocardial hypothermia during cardioplegic arrest. One complication of this technique is phrenic nerve injury (PNI). In an attempt to reduce the incidence of PNI, a prospective study was undertaken to evaluate the impact of phrenic nerve insulation on PNI during cardiac surgery. Seventy-six consecutive patients who underwent coronary revascularization constituted the control group (CG) and were compared with 76 patients who underwent a similar procedure with the addition of phrenic nerve insulation. In the intervention group (IG), a foam insulation pad was placed between the heart and the pericardium in an effort to reduce exposure of the phrenic nerve to iced saline solution slush. There was no difference in major demographic descriptors or operative variables between the CG and the IG, except that the internal mammary artery was used more frequently in the IG (64 percent vs 36 percent, p = 0.0006). The in-hospital mortality was similar between the groups (CG, 0.0 percent; IG, 1.3 percent; p = 1.0); however, the incidence of roentgenographically diagnosed PNI was much greater in the CG (14/76 patients [18 percent] vs 0/76 patients [0 percent]; p = 0.0006). Patients with and without PNI were similar with regard to age, gender, aortic cross clamp time, cardiopulmonary bypass time, and number of grafts (p greater than 0.05). All unilateral PNI occurred on the left. Three patients with bilateral PNI required tracheostomy and prolonged mechanical ventilation. In-hospital mortality was similar for patients with and without PNI (0 percent vs 0.7 percent), but mean postoperative hospital stay for patients with clinically diagnosed PNI was longer than for those without PNI (32 vs 11 days, p = 0.04). This prospective study demonstrates that the incidence of PNI can be significantly reduced by the routine use of phrenic nerve insulation.

Adult↗

PubMed1991

Measurement of prostaglandin G/H synthase and lipoxygenase activity in the stomach wall by HPLC.

A method for the determination of prostaglandin G/H synthase and lipoxygenase activities in tissues was developed and employed with rat gastric mucosa samples. Tissues and microsomes were incubated in a buffer containing nonionic detergent and 1.32 mM arachidonic acid for 10 min. Following extraction with ethyl acetate, the oxidation products of arachidonic acid were derivatized with panacyl bromide. A reversed-phase column and a quaternary mobile phase were used to separate and quantitate the panacyl bromide esters of prostaglandin E2 and leukotriene C4/D4. Prostaglandin G/H synthase and lipoxygenase activities were determined in gastric mucosa and were 371 +/- 66 and 173 +/- pg/mg/min, respectively.

Animals↗

PubMed1990

Measurement of 5-fluorouracil and its active metabolites in tissue.

The 5-fluorouracil content of serum, bile, pancreatic juice, liver, pancreas and muscle was measured by reversed-phase high-performance liquid chromatography using a mobile phase of 5 mM 1-heptanesulfonic acid in 5 mM acetic acid. Free or unmetabolized 5-fluorouracil was extracted from samples with a mixture of light petroleum-n-propanol (40:60). The active metabolites of 5-fluorouracil were hydrolyzed with hot perchloric acid to free 5-fluorouracil and the combined 5-fluorouracil content was extracted. The active metabolite fraction was calculated from the difference between the combined and the free fractions. A straight line plot of the peak areas against concentration was achieved and the detection limit was 50 ng/ml. Five minutes after stopping an intravenous infusion of 15 mg/kg of 5-fluorouracil in a dog, the serum contained only the free form, but other body fluids and tissues contained both free and metabolite fractions. The method may be useful to determine the amount of total drug in patient samples.

Animals↗

PubMed1990

Effect of verapamil on the gastric mucosal level of PGE2 during stress.

Prostaglandin E2 is one of the factors in the maintenance of gastric mucosal integrity and verapamil, a calcium channel blocker, has been shown to reduce gastric mucosal ulcerations during stress. To investigate whether this protective effect of verapamil is mediated via PGE2, four groups of 20 Holtzman rats were given either 1 ml of normal saline (NS) intraperitoneally (ip): 1 mg/kg of indomethacin (I) ip; 2 mg/kg of verapamil (V) ip or I followed by V. Then 10 animals from each group were submitted to stress by the cold-restraint method. After sacrifice, gastric mucosal ulcerations were counted and specimens of nonulcerated mucosa were assayed for PGE2 by HPLC. Stress-induced mucosal ulcerations were associated with a significant decrease in the gastric mucosal levels of PGE2 (from 64.2 to 32.7 pg; P less than 0.05). This effect was magnified by the administration of indomethacin (down to 21.0 pg). Verapamil significantly increased PGE2 levels both in the stressed (48.0 pg) and unstressed (99.9 pg) animals and significantly reduced ulcerogenesis when compared to either NS- or I-treated groups. This effect of verapamil was completely blocked by the administration of indomethacin. In conclusion, verapamil stimulates PGE2 synthesis and its protective effect against stress-induced mucosal damage seems to be mediated by PGE2.

Animals↗

PubMed1990