Ten tumors from 7 dogs were analyzed for estrogen receptors. Of 9 determined to be mast cell tumors, 6 were determined not to have estrogen receptors (less than 3 fmol of estradiol/mg of cytosol protein) and 3 were questionable (3 to 10 fmol of estradiol/mg). One tumor was a mixed mammary tumor and was determined to have estrogen receptors (12 fmol of estradiol/mg). Histologic grading of the mast cell tumors did not suggest a correlation with estrogen receptor values.

Thirty-eight grossly and histologically normal cat kidneys were examined ultrasonographically. The echogenicity of the renal cortex was subjectively evaluated by scoring it as largely or not largely different from the echogenicity of the renal medulla and as similar or not similar to the echogenicity of the renal sinus. The presence or absence of a medullary hyperechoic band was determined. The length, width, and height of each kidney was measured. Hematoxylin and eosin-stained sections of each kidney were examined microscopically. The amount of fat vacuoles in the tubular epithelium of the renal cortex was scored as plentiful or not plentiful. The presence or absence of medullary band of mineral deposits within the lumina of renal tubules was determined. A plentiful amount of fat vacuoles in renal cortex was associated positively with a large difference in echogenicity between cortex and medulla (P less than 0.01) and with similar echogenicity of cortex and sinus (P less than 0.01). The presence of a medullary hyperechoic band was associated positively with a band of mineral deposits within medullary tubular lumen (P 0.01). Kidneys with a large difference in echogenicity between cortex and medulla and kidneys with a plentiful amount of fat vacuoles were not significantly different in size (P = 0.56). These groups were larger (P less than 0.01) in length, width, and height than were kidneys without a large difference in echogenicity between cortex and medulla and kidneys that did not have plentiful cortical fat vacuoles.

Isolated segments of left dorsal colon and a side-to-side colocolostomy (between the left ventral colon and left dorsal colon) were surgically created in 6 adult ponies. Four segments, each separated by an empty segment, were inoculated (20 ml) with 1 of the following 4 solutions: phosphate buffered saline solution (PBSS)/1% polyethylene glycol (PEG); purified cholera toxin in PBSS/1% PEG (5 micrograms cholera toxin/ml of PBSS/1% PEG); lyophilized Salmonella typhimurium UCD 1755 culture lysate, reconstituted in PBSS/1% PEG; and viable S typhimurium UCD 1755 (10(8) organisms/ml of PBSS/1% PEG). Twenty hours following inoculation of the treatment solutions into the isolated colon segments, the ponies were reanesthetized. Fluid accumulation in the isolated segments was measured, and tissue samples from isolated segments were taken for examination by light microscopy and electron microscopy, and for measurement of mucosal cyclic adenosine monophosphate levels. There was fluid accumulation in segments inoculated with cholera toxin in 4 ponies (29.5 +/- 12.7 ml), and in segments inoculated with S typhimurium UCD 1755 culture lysate in 3 ponies. (14.0 +/- 8.7 ml). There was no fluid accumulation in segments inoculated with either the control solution (PBSS/1% PEG) or viable S typhimurium UCD 1755. There was significantly (P less than 0.05) less cyclic adenosine monophosphate in segments inoculated with cholera toxin, Salmonella lysate, and viable Salmonella, compared with control segments. Histologically, there were minimal changes in control segments, consisting of mild to moderate submucosal edema and capillary congestion. Changes in the other segments were more pronounced and included neutrophilic infiltration and exocytosis, with the changes increasing in severity in the segments inoculated with cholera toxin, S typhimurium culture lysate UCD 1755, and viable S typhimurium UCD 1755, respectively. Ultrastructurally, mucosa from control segments was normal. Mucosa from segments inoculated with cholera toxin had swollen endoplasmic reticula and basolateral separation of surface epithelial cells. Mucosa from segments inoculated with S typhimurium UCD 1755 culture lysate and viable S typhimurium UCD 1755 had swollen smooth and rough endoplasmic reticula, separation of epithelial cells, degeneration of microvilli, and goblet cell degeneration.