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G Christensen

Publications and source records attributed to G Christensen.

119 records · Page 7Linked to original sources
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Inhibition of granulocyte-derived proteases reduces the increase in plasma endothelin associated with myocardial ischemia in the pig.

Plasma endothelin (ET) is increased in association with myocardial infarction. The aim of the present study was to get insight into the mechanisms behind this ischemia-induced increase in plasma ET. Since granulocytes increase ET production in vitro, we examined to what extent inhibition of granulocyte-derived proteases could reduce the increase in plasma ET observed in association with myocardial ischemia. We infused Eglin C, a selective inhibitor of the granulocyte-derived proteases elastase, cathepsin G, and chymotrypsin, in pigs subjected to 90 min left anterior descending coronary artery occlusion followed by 210 min reperfusion (n = 7). Arterial plasma ET increased in an untreated control group (n = 7) from 5.0 +/- 0.6 (mean +/- SEM) fmol . ml-1 before myocardial ischemia to 6.1 +/- 0.6 fmol . ml. at 90 min ischemia and reached a maximum of 6.8 +/- 0.9 fmol . ml-1 at 90 min reperfusion. The increase in plasma ET associated with myocardial ischemia was almost completely abolished in the Eglin C treated group (p = 0.005). Plasma ET in the Eglin C treated animals was 4.7 +/- 0.4, 4.7 +/- 0.4, and 4.6 +/- 0.4 fmol . ml-1 before myocardial ischemia, at 90 min ischemia, and at 90 min reperfusion, respectively. Our study suggests a role for granulocyte-derived proteases in the increase in plasma ET associated with myocardial ischemia. We have shown that the increase in plasma ET associated with myocardial ischemia was reduced by inhibition of granulocyte-derived proteases using the selective protease inhibitor Eglin C.

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Benzalkonium chloride: a potential disinfecting irrigation solution.

OBJECTIVE: To determine the disinfecting properties of benzalkonium chloride as an irrigation agent. DESIGN: Comparison was made between irrigation of contaminated muscle strips with benzalkonium chloride and normal saline (control). SUMMARY OF BACKGROUND DATA: Benzalkonium chloride is a cationic disinfectant, which has questionable efficacy in an organic environment. However, no previous study has attempted to use high volumes of this cationic solution to overcome the neutralizing effect of organic tissue and thus maintain this detergent's germicidal properties. METHODS: 2.5 cm x 0.5 cm x 0.5 cm pieces of bovine muscle were aseptically cut from the center of freshly harvested beef muscle and incubated with 1.0 x 10(7) colony forming units of bacteria for 15 minutes. The muscle strips were then irrigated with either 100 mL, 1 L, or 10 L of benzalkonium chloride at a 1:2000 concentration in normal saline. Normal saline was used as the control. The muscle strips were sonicated to remove adherent bacteria; the number of living organisms was determined by quantitatively culturing the sonicate. RESULTS: In vitro, benzalkonium chloride was superior to normal saline at disinfecting bovine muscle (p < or = 0.001). When 10 L of benzalkonium chloride irrigation was used, no living bacteria could be recovered (p < or = 0.012). CONCLUSION: In this experimental setting benzalkonium chloride was an effective disinfection agent, with enhanced activity at large volumes.

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Comparison of castile soap, benzalkonium chloride, and bacitracin as irrigation solutions for complex contaminated orthopaedic wounds.

OBJECTIVE: The purpose of the present study was to determine the effects of cleaning a contaminated orthopaedic wound with different classes of wound irrigation solutions. STUDY DESIGN: Rats with a contaminated orthopaedic wound were randomized into treatment groups: normal saline (NS), castile soap (CS), benzalkonium chloride (BzC), bacitracin (Abx), or sequential irrigation with BzC, CS, and NS. INTERVENTION: Pseudomonas aeruginosa [P. aeruginosa; 1 x 10(6) colony-forming units (CFU)], or Staphylococcus aureus (S. aureus; 1 x 10(6) CFU) were placed into a paravertebral wound (containing a wire implant placed through a spinous process) and allowed to incubate for fifteen minutes. The wound was then irrigated with three liters of either NS, 0.05 percent CS, 0.03 percent BzC, Abx (33,000 units per liter) or underwent a sequential irrigation treatment (one liter each of BzC, CS, NS). MAIN OUTCOME MEASUREMENTS: The animals were observed daily for wound complications for fourteen days and then killed, and cultures of the wound were obtained. RESULTS: Pseudomonas aeruginosa: Both CS and the sequential irrigation treatment significantly lowered the rate of positive wound cultures when compared with NS (p < 0.05). Irrigation with BzC resulted in a higher rate of positive wound cultures and complications. The sequential irrigation treatment prevented the wound complications associated with irrigation with BzC alone. Staphylococcus aureus: Only BzC irrigation significantly lowered the rate of positive wound cultures when compared with NS (p < 0.05). CONCLUSION: The rate of positive wound cultures due to P. aeruginosa is effectively reduced by irrigation with CS alone or by the sequential irrigation treatment. When used alone, the antiseptic BzC results in a higher rate of positive wound cultures and wound complications. The wound complications seen with irrigation with BzC alone are prevented by the sequential irrigation treatment (BzC followed by CS and NS). The rate of positive wound cultures in this model due to S. aureus is not decreased by irrigation with CS; however, the rate of positive wound cultures is safely and effectively decreased with the use of BzC.

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[Pleuropneumonia in swine due to Haemophilus pleuropneumonia s. parahaemolyticus. II. Studies on the epidemiology and the relation to chronic pleuritis (pleural scars) in baconers (author's transl)].

Within a Danish practice area a serological examination was made of 268 breeding animals in 25 conventional sow herds with a view to screening for herd infection with haemophilus pleuropneumoniae. Average size of the herds was 76 year-sows including pregnant gilts (8--200). In 23 herds produced weaners were fed for slaughtering. The frequency of chronic pleuritis in slaughtered baconers in these herds was related to the frequency of seropositive sows in the herds. Three SPF-herds were included in the investigation, a SPF baconer herd reinfected with H. pleuropneumoniae, a SPF baconer herd reinfected with Mycoplasma suipneumoniae and a SPF breeding herd infected with Haemophilus parasuis. Complement fixation antibodies against Haemophilus pleuropneumoniae were found in breeding animals in 22 out of the 25 conventional sow herds. The average incidence of seropositive breeding animals in infected herds was 62% (7%--100%), highest in the largest herds. Likewise the highest serotitres were found in the largest herds, as an expression of strong infection pressure in large herds. The highest titre values were found in boars and young sows. The frequency of seronegative sows was the highest among the oldest sows. The registered frequency of chronic pleuritis among baconers from the examined herds was found increasing along with higher frequency of seropositive sows in the herds. On the basis of these observations and on the basis of a comparison of chronic pleuritis frequency among baconers in six herds (two with high frequency of seropositive breeding animals, one with moderate frequency of seropositive breeding animals, and 3 SPF-herds, one of which had been reinfected with Haemophilus pleuropneumoniae, one reinfected with Mycoplasma suipneumoniae and one that had experienced an acute outbreak of Glässer's Syndrome) it is concluded that haemophilus pleuropneumoniae is the absolutely most important cause of chronic pleuritis in baconers. A pronounced seasonal variation was found in the monthly pleuritis frequency among baconers in herds strongly infected with Haemophilus pleuropneumoniae, the minumum frequency being in January-February, and the maximum frequency in July-October. It is supposed that the observed variation in frequency of chronic pleuritis is caused by changes in the environmental climate. High frequency of chronic pleuritis is caused by changes in the environmental climate. High frequency is found in the summer in slaughtered baconers, which have been clinically affected by pleuropneumonia as piglets and weaners under inferior climatic conditions during the colder season of the year.

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