Development of a rabbit's urethral sphincter deficiency animal model for anatomical-functional evaluation

OBJECTIVE: The aim of the study was to develop a new durable animal model (using rabbits) for anatomical-functional evaluation of urethral sphincter deficiency. MATERIALS AND METHODS: A total of 40 New Zealand male rabbits, weighting 2.500 kg to 3.100 kg, were evaluated to develop an incontinent animal model. Thirty-two animals underwent urethrolysis and 8 animals received sham operation. Before and at 2, 4, 8 and 12 weeks after urethrolysis or sham operation, it was performed cystometry and leak point pressure (LPP) evaluation with different bladder distension volumes (10, 20, 30 mL). In each time point, 10 animals (8 from the study group and 2 from the sham group) were sacrificed to harvest the bladder and urethra. The samples were evaluated by H&E and Masson's Trichrome to determine urethral morphology and collagen/smooth muscle density. RESULTS: Twelve weeks after urethrolysis, it was observed a significant decrease in LPP regardless the bladder volume (from 33.7 ± 6.6 to 12.8 ± 2.2 cmH2O). The histological analysis evidenced a decrease of 22% in smooth muscle density with a proportional increase in the collagen, vessels and elastin density (p < 0.01). CONCLUSIONS: Transabdominal urethrolysis develops urethral sphincter insufficiency in rabbits, with significant decrease in LPP associated with decrease of smooth muscle fibers and increase of collagen density. This animal model can be used to test autologous cell therapy for stress urinary incontinence treatment.

Expression of TERT in precancerous gastric lesions compared to gastric cancer

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46 percent of IM, 50 percent of GU, and 79 percent of GC. The relative mean level of TERT mRNA after normalization with the β-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 ± 2.605 and 2.730 ± 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 ± 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38 percent of IM, 39 percent of GU, and 55 percent of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.

Analysis of p53 expression and proliferative assessment using PCNA in localized prostate carcinoma

The surgical specimens from 51 men submitted to radical prostatectomy for localized prostate cancer were examined by immunohistochemistry using proliferation cell nuclear antigen (PCNA) monoclonal antibody to evaluate the proliferative index (PI). The relationship between PI, biological variables and p53 protein expression was evaluated by immunohistochemistry. PI was low in invasive localized prostate carcinoma (mean, 12.4percent) and the incidence of PCNA-positive cells was significantly higher in tumors with p53 expression (P = 0.0226). There was no statistical difference in PCNA values when biological parameters such as Gleason score, tumor volume, extraprostatic involvement, seminal vesicle infiltration or lymph node metastasis were considered. We conclude that proliferative activity is usually low in prostate carcinoma but is correlated with p53 immune staining, indicating that p53 is important in cell cycle control in this neoplasm

Hepatic damage during acute pancreatitis in the rat

We studied the alterations in the metabolism of liver mitochondria in rats with acute pancreatitis. Male Wistar rats were allocated to a control group (group I) and to five other groups corresponding to 2,4, 12,24 and 48 h after the induction of acute pancreatitis by the injection of 5 per cent sodium taurocholate into the pancreatic duct. Sham-operated animals were submitted to the same surgical steps except for the induction of acute pancreatitis. Mitochondrial oxidation and phosphorylation were measured polarographically by determining oxygen consumption without ADP (basal respiration, state 4) and in the presence of ADP (activated respiration, state 3). Serum amylase, transaminases (ALT and AST) and protein were also determined. Ascitic fluid, contents of amylase, trypsin and total protein were also determined and arterial blood pressure was measured in all groups. In ascitic fluid, trypsin and amylase increased reaching a maximum at 2 and 4h, respectively. Serum amylase increased at 2 h reaching a maximum at 4 h. Serum transaminase levels increased at 12 and 24 h. After 2 h (and also 4 h) there was an increase in state 4 respiration (45.65 + 1.79 vs 28.96 + 1.50) and a decrease in respiration control rate (3.53 + 0.09 vs 4.45 + 0.08) and in the ADP/O ratio (1.77 + 0.02 vs 1.91 + 0.01) compared to controls (P<0.05). These results indicate a disruption of mitochondrial function, which recovered after 12 h. In the 48-h groups there was mitochondrial damage similar to that occurring in ischemic lesion. Beat-to-beat analysis (30 min) showed that arterial blood pressure remained normal up to 24 h (111 + 3 mmHg) while a significant decrease occurred in the 48-h group (91 + 4 mmHg). These data suggest biphasic damage in mitochondrial function in acute pancreatitis: an inital uncoupled phase, possibly secondary to enzyme activity, followed by a temporary recovery and then a late and final dysfunction, associated with arterial hypotension, possibly related to ischemic damage.