Carolyn K. Montgomery

Role of acid and pepsin in acute experimental esophagitis.

The roles of acid and pepsin in the production of acute feline esophagitis have been studied. Acid alone in high concentrations (pH 1.6 and 1.3) caused esophagitis. At lower acid concentration (pH 1.6 and 2.0), pepsin is an important factor in producing esophagitis. A suitable acid-pepsin solution has been selected for use as a standardized insult in an experimental model of esophagitis.

Prospective evaluation of systematic sextant transition zone biopsies in large prostates for cancer detection

OBJECTIVES A prospective evaluation was performed to define the role of systematic transition zone (TZ) biopsies in prostates larger than 50 cc. METHODS From August 1994 to July 1997, 213 consecutive patients referred because of an abnormal digital rectal examination or prostate-specific antigen greater than 4.0 ng/mL had a calculated prostate size greater than 50 cc by transrectal ultrasound (TRUS) measurement. These patients underwent TRUS-guided sextant biopsies of the peripheral zone (PZ) and TZ. RESULTS The median calculated prostate size was 70 cc with a TZ size of 39 cc. Fifty-five cases of carcinoma of the prostate were found, giving a 26% detection rate. The TZ biopsies detected cancer in 30 of the 55 patients (55% sensitivity) compared with the 47 patients detected by the PZ biopsies (85% sensitivity). Seven cancers (13%) were detected only by the additional TZ biopsies. TZ biopsies revealed bilateral tumors when the PZ biopsies had shown unilateral disease in 2 cases. In 6 cases the TZ biopsies showed higher Gleason grade tumors than was found in the PZ. In the 30 cases with positive TZ biopsy, concordance between the PZ and TZ biopsies occurred in 74% (133 of 180) of the sectors. The PZ biopsy detected cancer in 43 of 66 corresponding sectors that had positive TZ biopsies, giving a sensitivity of 65% and a negative predictive value of 80%. CONCLUSIONS Routine PZ biopsies missed detecting 13% of the cancers found with the addition of sextant TZ biopsies in patients with large prostates (greater than 50 cc). In addition, 14% of the patients with cancer had upgrading or detection of bilateral tumor with the added biopsies. Routine systematic sextant TZ biopsies should be considered in patients with prostates greater than 50 cc in size.

Experimental study of the use of collagen tubes for implantation of particulate hydroxylapatite

A pilot study was conducted in rats to evaluate the role of collagen tubes in subperiosteal implantation of particulate hydroxylapatite. The results showed that the collagen tube shaped the hydroxylapatite, facilitated precise implant placement, and prevented particle migration while not interfering with healing.

Trophic effects of gastrin on the exocrine pancreas in rats

Abstract In three groups of hypergastrinemic rats with gastrojejunostomy and gastric antrum transplanted to the colon (AT), pancreatic structure and function were studied 2, 6, or 16 weeks postoperatively. Fasting serum gastrin was 658 ± 88 pg/ml in AT animals compared with 87 ± 12 pg/ml in sham-operated controls. Another group of rats prepared with antrectomy and gastrojejunostomy (A) had low serum gastrin concentrations; they were studied 12 weeks postoperatively. Pancreatic juice was collected after iv secretin or CCK and was analyzed for [HCO3−], [Cl−], and protein. Pancreas histology and DNA/RNA per milligram of pancreatic protein was the same in all groups. A twofold increase in [HCO3−] and volume of secretion at 2 weeks in AT animals suggested that gastrin exerted a trophic effect on the ducts. By 6 weeks pancreas weight had increased, probably reflecting acinar growth. By 16 weeks pancreatic secretion was qualitatively similar to the control group, but the pancreas weights were 35% greater and absolute secretory capacities were 50% greater. In the A animals, pancreas weights and protein secretion were unchanged, but HCO3− secretion was impaired. We conclude that chronic endogenous hypergastrinemia produced functionally significant hyperplasia of both the duct and acinar cells.

Sequential gross, microscopic and roentgenographic features of acute feline esophagitis.

The sequential gross, histologic and roentgenographic changes of acute esophagitis have not been correlated previously. In this study, acute feline esophagitis was produced by intraesophageal infusion of an acid-pepsin solution. Thirty animals (Group I) were infused one hour and 22 animals (Group II) were infused two hours. Animals, three to eight from each group, were sacrificed either immediately or at one, three, seven, 14 or 28 days after infusion. Esophagitis limited to the mucosa (Group I) did not produce roentgenographic abnormalities. When the inflammatory phase of esophagitis extended into the submucosa or submucosa and muscularis externa (Group II), roentgenographic findings of esophageal luminal narrowing caused by wall thickening usually were recorded. Mucosal ulceration was not evident on esophagrams taken in the living animal. Four weeks after infusion, roentgenograms were normal and histologic evidence of healing without fibrosis was demonstrated.

Use of collagen tubes for implantation of hydroxylapatite: An experimental study

Collagen tubes were compared with routine injection for placement of hydroxylapatite in mandibular defects. It was found that the collagen film containers were effective in providing easier handling, more effective shaping, and less migration of particles.

Collagen tubes: Role in superiosteal contour augmentation

Collagen-contained implants of particulate hydroxylapatite (C-HA) were compared to implants of hydroxylapatite alone (HA). The collagen-contained implant was more rapidly and more firmly attached to the recipient site and demonstrated more consistent particle consolidation than implants of HA alone. Additionally, the collagen did not interfere with the favorable properties of the particulate hydroxylapatite. Results are excellent for the (C-HA) implant and warrant further investigation in both animals and in man.