Cardiovascular pathology possibly associated with ketamine/xylazine anesthesia in Dutch belted rabbits

BACKGROUND AND PURPOSE

After myocardial necrosis and fibrosis was observed in five rabbits which had been anesthetized a variable number of times, the potential relationship of these lesions and anesthesia was evaluated in 35 other rabbits.

METHODS

Anesthesia was induced by intramuscular administration of ketamine and xylazine followed by infusion of lactated Ringer's solution also containing ketamine and xylazine. Group A rabbits (n = 9) were subjected to multiple anesthesias and were evaluated by echocardiography, thoracic radiography, electrocardiography, determination of serum coronavirus titer, vitamin E concentration, and complete necropsy. Prior to a single acute procedure followed by necropsy, group B rabbits (n = 11) were evaluated by echocardiography only. Group C rabbits (n = 10) had never been anesthetized and were necropsied after euthanasia. Group D rabbits (n = 5) had intermediate anesthesia exposure history and were evaluated by echocardiography only. Myocardial fibrosis was scored semi-quantitatively on a scale of 0 to 4.

RESULTS

Canine coronavirus test results were negative; hypovitaminosis E was evident, and fibrosis scores were significantly increased in group A, compared with group B or group C, rabbits.

CONCLUSION

Etiologic differentials included alpha2-agonist-mediated coronary vasoconstriction with associated myocardial hypoperfusion, hypovitaminosis E and free radical injury, and other anesthetic-induced physiologic trespass.

Mice lacking secretory phospholipase A2 show altered apoptosis and differentiation with Helicobacter felis infection

BACKGROUND & AIMS

Infection with Helicobacter pylori uniformly leads to a chronic superficial gastritis that may progress to atrophic gastritis, a premalignant process. A mouse model of Helicobacter felis infection was used to study possible genetic determinants of the response to infection.

METHODS

Three inbred mouse strains with known secretory phospholipase A2 (sPLA2) genotypes [BALB/c (+/+), C3H/HeJ (+/+), and C57BL/6 (-/-)] were orally infected with H. felis and examined longitudinally using routine histology, immunocytochemistry, electron microscopy, proliferating cell nuclear antigen, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and Northern and Western blot studies.

RESULTS

Only the C57BL/6 strain showed increased gastric fundic proliferation and apoptosis in response to infection. In addition, the C57BL/6 mouse showed a marked loss of parietal and chief cells, along with a marked expansion of an aberrant gastric mucous cell lineage that stained positive for spasmolytic polypeptide. In contrast, no significant change in these cell types was observed in BALB/c and C3H/HeJ strains. Increased expression of sPLA2 was observed in BALB/c and C3H/HeJ after H. felis infection, whereas sPLA2 expression was absent in C57BL/6 mice.

CONCLUSIONS

H. felis infection leads to increased apoptosis and altered cellular differentiation in the C57BL/6 mouse, a strain that lacks gastric sPLA2 expression. Because sPLA2 has been identified recently as the MOM1 (modifier of MIN) locus that influences polyp formation in the colon, these studies suggest that sPLA2 may also influence the gastric epithelial response to Helicobacter infection.