Mechanical, histologic, and biochemical effects of canine rectal formalin instillation.

UNLABELLED: Instillation of 4 percent formalin effectively treats radiation hemorrhagic proctitis; however, little is known regarding its side effects. PURPOSE: The study contained herein was undertaken to determine rectal compliance and collagen content, mucosal and vascular histologic changes, and kinetics of formalin absorption following instillation. METHODS: Fifteen mongrel dogs (50-60 pounds) were randomized into five experimental groups according to time elapsed from formalin treatment: control, acute, one week, two weeks, and four weeks. Formalin was instilled in 30-ml aliquots to a total volume of 400 ml. Rectal compliance (closed manometry system) was assessed pre-formalin and post-formalin at the designated time interval. Serum formalin metabolites were determined at time 0, 0.5, 1, and 3 hours. A segment of rectal wall was analyzed for collagen content, mucosal injury, and blood vessel density. RESULTS: Serum formalin levels peaked within 30 minutes, returning to normal by 3 hours. With the exception of one dog, toxic levels were not reached at any time during the study. No dogs experienced sepsis, fever, or altered gastrointestinal function. Acute and one-week dogs showed mild diffuse proctitis and mucosal slough, which healed within two weeks. Rectal compliance and collagen content were unchanged. Mucosal blood vessels decreased in number early (P = 0.03). CONCLUSIONS: Instillation of 4 percent formalin in sequential aliquots of a small volume that is kept in contact for a short period of time is safe. Serum formalin levels generally do not reach toxic levels, and the slight elevation in formalin concentration that was seen returns to normal within three hours. Formalin-induced proctitis heals within two weeks, and no long-term changes in rectal compliance or collagen content were seen.

Absorption kinetics of rectal formalin instillation.

Formalin instillation has become an accepted treatment of radiation-induced hemorrhagic cystitis and proctitis since the initial report by Brown in 1969 (Med. J. Aust. 1:23, 1969). Although its use is widespread, no studies have been performed to determine the safest, volume or duration of formalin exposure. The purpose of our study was to determine the optimum technique for instillation and the safety margin regarding the maximum time that formalin can be in contact with the rectal mucosa without causing serum toxicity. In a pilot canine study, 4% neutral buffered formalin was instilled into the rectum in 30 ml aliquots for 60 seconds each after which each aliquot was withdrawn; a total volume of 400 ml was used. Our subsequent experiment involved rectal instillation of a single formalin bolus of 100 ml for 1 hour without removal during this time. Formalin metabolites were measured in the blood and urine to assess toxicity. Results indicate that with the latter technique serum formic acid reaches toxic levels within 15 minutes of instillation and may stay elevated for several hours. Metabolites in the urine similarly increase within 15 minutes, lagging only shortly behind the rise in serum levels. Performing formalin instillation in a series of 30 ml aliquots appears to be a safer treatment, as toxic serum levels were not reached and their slight rise above baseline returned to normal within 3 hours.

Intestinal anastomotic healing at varying times after irradiation.

The use of preoperative and intraoperative irradiation as surgical adjuncts in cancer management has led to concerns regarding post-operative wound healing. The optimum time to construct an intestinal anastomosis after irradiation has not been determined. The aim of this study was to evaluate anastomotic wound healing at varying times after irradiation. One hundred eighty-seven male Sprague-Dawley rats were randomized into seven experimental groups. Group I (control) had a sutured anastomosis and no irradiation. Groups II-VII received a single dose of 20 Gy intraoperatively. In group II, a sutured anastomosis incorporating irradiated bowel was performed immediately after irradiation. Groups III-VII underwent a second laparotomy to undergo a sutured anastomosis with irradiated bowel at 2 days, 1 week, 2 weeks, 3 weeks, and 4 weeks after irradiation. The rats were sacrificed 7 days after the anastomosis was created and the segment of terminal ileum containing the anastomosis was harvested. Tensile strength, hydroxyproline content, and modified Black irradiation damage scores were determined: [table: see text] The increasing modified Black scores reflect the progressive nature of irradiation damage over time. Increasing hydroxyproline content is seen after irradiation but this does not imply increasing wound strength. There was a return of tensile strength to normal levels by 2 weeks. These findings suggest that normal wound healing can be expected if a minimum of 2 weeks elapses between irradiation and intestinal anastomosis.

Immunohistochemical detection of mutant P53 protein and human papillomavirus-related E6 protein in anal cancers.

PURPOSE: The wild-type P53 protein, a product of the P53 gene, is a normal growth controlling protein. Mutation of the P53 gene generates a mutant P53 protein which promotes tumor formation through loss of growth suppression. Some of the agents responsible for P53 gene mutation are known, one of which may be tumorigenic human papillomavirus (HPV) infection. Anal cancers are demonstrating a changing trend in the affected population, from older females in the older reported series to younger males more recently. This may be a reflection of infection with tumorigenic HPV types 16 and 18. The E6 oncoprotein of these viruses inactivates the growth-controlling wild-type P53 protein. In this study, our purpose was to determine the incidence of mutant P53 and HPV-16 and 18-related E6 protein and their coexpression in anal cancers. METHODS: We examined 29 anal cancers immunohistochemically for mutant P53 protein, HPV 16 and 18 E6 protein, and coexpression of the two. RESULTS: Mutant P53 protein was present in 58.6 percent of anal cancers overall and in 85.7 percent of anal adenocarcinomas. E6 oncoprotein was present in five cases (17.2 percent), all of which were squamous-cell carcinomas. Coexpression of both mutant P53 and E6 proteins was seen in only three cases (10.3 percent). CONCLUSION: Although tumorigenic HPV may be an important cause for P53 gene mutation in anal cancers, perhaps other mutagenic factors play a predominant role.

Variable expression of P-glycoprotein in normal, inflamed, and dysplastic areas in ulcerative colitis.

Screening programs for the detection of cancer in ulcerative colitis are inexact and not always successful in finding early, curable cancers. P-glycoprotein is a membrane-based, energy-dependent protein found in varying degrees within normal human tissue. P-glycoprotein is overexpressed in malignant tumors, particularly colorectal cancer, and is known to convey resistance to certain anticancer drugs by acting as a membrane "pump." The purpose of this study was to determine the expression of this protein in inflamed and premalignant colonic epithelium, compare its expression with normal controls, and assess its potential use as a screening tool for high-risk patients with ulcerative colitis. Using immunohistochemical techniques, the colons of 21 patients (10 with dysplasia) with ulcerative colitis were stained with monoclonal antibody C-219 (MAbC219) specific for P-glycoprotein. P-glycoprotein was expressed in 38 percent of normal areas, 71 percent of inflamed areas (P = 0.0156), and 70 percent of dysplastic areas. Comparing the level of expression when progressing from normal to inflamed areas within a given patient, 11 patients (52 percent) showed increased expression, 8 (38 percent) showed equal expression, and only 2 (10 percent) showed decreased expression (P = 0.0225). Comparing expression when progressing from inflamed to dysplastic areas (10 patients), 7 showed equal expression and 3 showed increased expression (P = 0.25). Increasing duration of disease was associated with a significant increase in P-glycoprotein expression, but only in histologically normal areas. Duration of disease had no effect on P-glycoprotein expression in inflamed or dysplastic areas. Similarly, when surgery was performed for elective reasons, there was a significant overexpression of P-glycoprotein, but only in histologically normal areas. Our findings suggest that the increase in P-glycoprotein expression from normal to inflamed and dysplastic areas reflects the premalignant nature of ulcerative colitis and occurs early in the course of the disease. Further research needs to be done to determine its role in cancer surveillance.

Relationship of the expression of the multidrug resistance gene product (P-glycoprotein) in human colon carcinoma to local tumor aggressiveness and lymph node metastasis.

P-glycoprotein mediates classic multidrug resistance by functioning as an efflux pump that excretes lipophilic chemotherapeutic drugs from cancer cells. We now report an association of P-glycoprotein in colon carcinomas with another tumor property, i.e., enhancement of local tumor aggressiveness. P-glycoprotein was detected with monoclonal antibody immunohistochemistry in 65 of 95 primary colon adenocarcinomas, which were stage B1 or greater. In all but 1 of the 95 cases, solitary invading carcinoma cells were present at the leading edge of the tumor. This subpopulation of invasive carcinoma cells expressed P-glycoprotein (P-Gp+) in 47 of the 95 surgically resected colon specimens. Cases were grouped on the basis of the presence (Group 1, 47 cases) or absence (Group 2, 48 cases) of P-Gp+ invasive carcinoma cells. There was a significantly greater incidence of vessel invasion (P less than 0.001) and lymph node metastases (P less than 0.01) in Group 1 cases. Groups 1 and 2 did not differ with respect to tumor size, depth of invasion of the bowel wall, histological grade, maximum tumor size, mitotic index, mucin production, or presence of perineural invasion (P greater than 0.1). Our findings indicate that P-Gp+ invasive colon cancer cells may have an increased potential for dissemination, suggesting that P-glycoprotein may influence cell behavior.

ABO blood type predicts the cytolocalization of anti-P-glycoprotein monoclonal antibody reactivity in human colon and ureter.

Classic multidrug resistance is mediated by a P-glycoprotein. Using monoclonal antibody C219 (MAb C219) in an immunohistochemical study, we found high levels of putative Golgi P-glycoprotein in normal columnar and transitional epithelium in subpopulations of patients with specific blood types. For example, Golgi staining was present in blood type A patients in 46% of normal colon samples (N = 21) and 88% of normal ureter samples (N = 17). In comparison, Golgi staining was present in blood group O patients in only 6% of normal colon samples (N = 34) and in 0% of normal ureter samples (N = 19). The association of MAb C219 Golgi staining with blood type A and lack of Golgi staining with blood type O was statistically significant in normal colon (P = .001) and normal ureter (P less than .0001). Inappropriate hyperexpression of P-glycoprotein was frequently found in colon carcinomas. Additional evidence that Golgi MAb C219 reactivity represents P-glycoprotein is presented. This includes (1) immunostaining of Golgi with two anti-P-glycoprotein MAbs, C219 and JSB-1, and (2) experiments in which Mab C219 Golgi reactivity was blocked by preincubation of MAb C219 with a specific P-glycoprotein epitope-containing peptide. The high degree of association of Golgi P-glycoprotein with blood type A may suggest a role for P-glycoprotein in processing or trafficking of specific blood group antigens.

Radiation-induced sarcoma of the breast in a female adolescent. Case report with histologic and therapeutic considerations.

A 14-year-old girl developed a radiation-induced sarcoma of the left breast after successful combined surgical and radiation therapy of a left adrenal carcinoma when she was 9 months old. The breast lesion was histologically described as a stromal sarcoma with fibrosarcomatous and myxosarcomatous areas. The second primary lesion and local recurrence of this was treated with surgery. At each recurrence the tumor became more aggressive both clinically and histologically, and eventually proved fatal.

Tamm-Horsfall protein is a marker of renal and extra-renal rhabdoid tumours.

A monoclonal antibody (MAb) to Tamm-Horsfall protein (THP) was used to stain 6 renal rhabdoid tumours (RRT) and 2 primary extra-renal rhabdoid tumours (E-RRT). One of the E-RRT was a tumour from the posterior fossa of a 3-year-old child and the other was a lump from the right side of the neck in an 18-month-old girl. Five of 6 RRT and both cases of E-RRT were positive for THP. Both cases of E-RRT also reacted with vimentin and cytokeratin MAbs. On electron microscopy, cells from both E-RRT were seen to contain concentric whorls of intermediate filaments characteristic of rhabdoid tumours. Viable tissues from one RRT and one E-RRT (the posterior fossa tumour) were available for tissue culture. Ninety-five percent of the cells growing out of both tumours were polygonal and approximately 5% of these cells were THP-positive.

Primary rhabdoid tumour of the brain.

A posterior fossa tumour in a 3 year old child is presented with characteristic histological, ultrastructural and immunohistochemical features of rhabdoid tumour. Many tumour cells contained cytoplasmic eosinophilic hyaline inclusions. Ultrastructurally concentric whorls of 10 nm intermediate filaments were identified. Immunohistochemical staining disclosed vimentin, cytokeratin and epithelial membrane antigen positivity. Renal and extrarenal rhabdoid tumours have been well documented but a primary rhabdoid tumour of the brain is extremely rare. Additional ultrastructural features seen were tubular crystalline inclusions in endoplasmic reticulum and abnormal large mitochondria.