Bladder smooth muscle strip contractility as a method to evaluate lower urinary tract pharmacology.

We describe an in vitro method to measure bladder smooth muscle contractility, and its use for investigating physiological and pharmacological properties of the smooth muscle as well as changes induced by pathology. This method provides critical information for understanding bladder function while overcoming major methodological difficulties encountered in in vivo experiments, such as surgical and pharmacological manipulations that affect stability and survival of the preparations, the use of human tissue, and/or the use of expensive chemicals. It also provides a way to investigate the properties of each bladder component (i.e. smooth muscle, mucosa, nerves) in healthy and pathological conditions. The urinary bladder is removed from an anesthetized animal, placed in Krebs solution and cut into strips. Strips are placed into a chamber filled with warm Krebs solution. One end is attached to an isometric tension transducer to measure contraction force, the other end is attached to a fixed rod. Tissue is stimulated by directly adding compounds to the bath or by electric field stimulation electrodes that activate nerves, similar to triggering bladder contractions in vivo. We demonstrate the use of this method to evaluate spontaneous smooth muscle contractility during development and after an experimental spinal cord injury, the nature of neurotransmission (transmitters and receptors involved), factors involved in modulation of smooth muscle activity, the role of individual bladder components, and species and organ differences in response to pharmacological agents. Additionally, it could be used for investigating intracellular pathways involved in contraction and/or relaxation of the smooth muscle, drug structure-activity relationships and evaluation of transmitter release. The in vitro smooth muscle contractility method has been used extensively for over 50 years, and has provided data that significantly contributed to our understanding of bladder function as well as to pharmaceutical development of compounds currently used clinically for bladder management.

Excitatory effects of bombesin receptors in urinary tract of normal and diabetic rats in vivo.

AIMS: Bombesin receptors (BB receptors) and bombesin related peptides are expressed in the lower urinary tract of rodents. Here we investigated whether in vivo activation of BB receptors can contract the urinary bladder and facilitate micturition in sham rats and in a diabetic rat model of voiding dysfunction. MATERIAL AND METHODS: In vivo cystometry experiments were performed in adult female Sprague-Dawley rats under urethane anesthesia. Diabetes was induced by streptozotocin (STZ; 65mg/kg, i.p.) injection. Experiments were performed 9 and 20weeks post STZ-treatment. Drugs included neuromedin B (NMB; BB1 receptor preferring agonist), and gastrin-releasing peptide (GRP; BB2 receptor preferring agonist). KEY FINDINGS: NMB and GRP (0.01-100µg/kg in sham rats; 0.1-300µg/kg in STZ-treated rats, i.v.) increased micturition frequency, bladder contraction amplitude and area under the curve dose dependently in both sham and STZ-treated rats. In addition, NMB (3, 10µg/kg i.v.) triggered voiding in >80% of STZ-treated rats when the bladder was filled to a sub-threshold voiding volume. NMB and GRP increased mean arterial pressure and heart rate at the highest doses, 100 and 300µg/kg. SIGNIFICANCE: Activation of bombesin receptors facilitated neurogenic bladder contractions in vivo. Single applications of agonists enhanced or triggered voiding in sham rats as well as in the STZ-treated rat model of diabetic voiding dysfunction. These results suggest that BB receptors may be targeted for drug development for conditions associated with poor detrusor contraction such as an underactive bladder condition.

Multimodality treatment of peritoneal carcinomatosis from colorectal cancer: first results of a new German centre for peritoneal surface malignancies.

BACKGROUND: The presence of peritoneal carcinomatosis arising from colorectal cancer is associated with a poor prognosis. It was the purpose of this study to analyze morbidity, mortality, and survival after major cytoreductive surgery and intraperitoneal chemotherapy. MATERIALS AND METHODS: Thirty-two patients with peritoneal carcinomatosis were operated between April 2004 and June 2006 with the aim of complete macroscopical cytoreduction. All had a primary colorectal carcinoma. Surgery in these patients was followed by hyperthermic intraperitoneal chemotherapy (HIPEC) consisting of mitomycin C and doxorubicin. Data were analyzed retrospectively. RESULTS: Of all patients, 16 had appendix and 16 non-appendiceal colorectal carcinoma. A macroscopically complete cytoreduction was achieved in 24 patients by parietal and visceral peritonectomy procedures. All resections were combined with HIPEC. Overall morbidity was 34%. Most frequent surgical complications were intestinal obstruction (4/32), enteric fistula (2/32), pancreatitis (2/32), and bile leakage (2/32). One patient presented grade 4 renal toxicity. There was no hospital mortality. The median follow-up was 12 months. The 1-year overall survival rate is 96%. All patients after complete cytoreduction are still alive. CONCLUSIONS: Cytoreductive surgery combined with HIPEC is associated with an acceptable morbidity and low mortality. Complete cytoreduction may improve survival, particularly in well-selected patients having a low tumor volume and no extra-abdominal metastases.

[Surgical management of patients with peritoneal carcinomatosis of gastrointestinal origin]. / Chirurgische behandlung von peritoneal disseminierten gastrointestinalen tumoren.

Peritoneal carcinomatosis is found in approximately 15 % of patients with colorectal cancer during the course of their disease, and is associated with a poor prognosis. Even more patients with gastric cancer develop peritoneal seeding. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) have been introduced in the past decade and have led to 5-year survival rates of 30 to 40 % for selected patients with colorectal cancer and peritoneal carcinomatosis. These numbers have been demonstrated by many retrospective analyses and by prospective Phase II studies. The clinical assessment to select patients who will benefit from the combined therapy and achievement of complete macroscopic cytoreduction both play a crucial role. Less favourabale results have been achieved for patients suffering from stage IV gastric cancer with peritoneal seeding. Promising results were demonstrated for postoperative intraperitoneal chemotherapy following curative gastrectomy. Patients with hepatic, biliary and pancreatic cancers and peritoneal carcinomatosis do not benefit from cytoreductive surgery. There is a need for further multicentre, prospective trials analysing the use of hyperthermic intraperitoneal chemotherapy. They should be conducted in the specialised centres by interdisciplinary teams.

The accuracy of abdominal ultrasound in the assessment of bowel disorders.

BACKGROUND: Little is known about the sensitivity, specificity, and predictive values of transabdominal ultrasonographic (US) findings in a teaching hospital setting. METHODS: We carried out a prospective study including 227 patients with symptoms suggestive of inflammatory bowel disorder. The Picker 9200 CS equipment (5-mHz curved-array probe) was used to obtain bowel images. Gastrointestinal endoscopy, enteroclysis, bowel enema, computed tomography scan, or bowel surgery was used as reference. RESULTS: Of 227 patients, 168 had pathologic findings of the bowel as final diagnosis. The overall sensitivity of US was 76%, whereas the positive predictive value was 98%. Overall specificity was 95%. The negative predictive value for bowel disorders was only 58%, since US missed pathologic findings in 48 patients. Subgroup analysis showed a sensitivity of 84% for Crohn's disease, 66% for ulcerative colitis, 46% for bowel tumors, and 60% for diverticulitis. Topographic comparisons showed that US detected inflammatory bowel-wall alterations preferentially in the terminal ileum and colon, whereas abnormalities in the duodenum, jejunum, and rectum were frequently missed (sensitivity, 10%-20%). CONCLUSIONS: Positive US findings are useful for the diagnosis of bowel processes. US is highly predictive albeit not disease-specific. Negative US examinations, however, do not exclude pathologic bowel processes. A topographic location of pathologic US findings is mostly confined to the colon.