Evaluation of effects of chitosan in preventing hemorrhagic cystitis in rats induced by cyclophosphamide.
ABSTRACT Hemorrhagic cystitis is a common problem following cyclophosphamide or radiation therapy. Chitosan has been shown to be an effective hemostatic agent and promoter of wound healing in animal experiments. We evaluated the safety and efficacy of intravesical chitosan in an animal model of cyclophosphamide cystitis. Hemorrhagic cystitis was induced in female F344 rats by intraperitoneal cyclophosphamide, 100 mg/kg. Chitosan solution (0.3 ml) was instilled intravesically on day 1 (Group 1), on days 1, 3, and 5 (Group 2), or 1 hour after the administration of cyclophosphamide (Group 3). The rats in group 4 were treated with chitosan diluent on day 1 after cyclophosphamide, and the rats in group 5 received intravesical chitosan without cyclophosphamide. Sequential examination revealed decreased mortality and lower incidences of severe bladder bleeding, necrosis and inflammation in Group 3. Treatment delayed until after the appearance of the cystitis, especially repeated treatments, appeared to make the cyclophosphamide-induced changes worse. Used within 1 hour of cyclophosphamide administration, before the cystitis develops, chitosan seemed to have the possibility to inhibit the appearance of hemorrhagic cystitis. In addition to the changes in the bladder, severe changes occurred in the kidneys secondary to cyclophosphamide.
Full-textDOI: · Available from: Takehiko Okamura, Mar 25, 2014
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ABSTRACT: Stents are largely used in surgical procedures to relieve pathological obstructions. The purpose of the present study was to design and prepare a biocompatible stent with a self-expandable mechanism. Thin films were prepared from deacetylated chitosan (4% w/v) dissolved in acetic acid solution (2% v/v). The chitosan films were tested by a calibrated tensiometer to measure the Young's module (E). The films were used to manufacture stents by pulling and winding them around a cylindrical rod in a helical fashion. Thirteen stents (diameter = 0.5 +/- 0.05 mm, length approximately 4 mm) were inserted into the vas deferens of wistar rats. Upon stent insertion, the vasal anastomosis was achieved with a laser-soldering technique. The animals were sacrificied 8 weeks later. The stress test showed that the chitosan film was elastic (maximum strain = 105% +/- 6%, E = 0.7655 +/- 0.0288 Mpa). The stents self-expanded by releasing their elastic energy. All the stents but one remained open inside the vasa despite high incidence of sperm granuloma. A biocompatible and self-expandable stent with a helical design is proposed.Biomaterials 08/2001; 22(13):1869-74. DOI:10.1016/S0142-9612(00)00371-9 · 8.31 Impact Factor
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ABSTRACT: Information about the frequency, intensity, prevention, treatment, and management of bladder hemorrhages, especially in patients with advanced bladder carcinoma, is lacking or scarce. The main treatment options are classified as intravesical treatment attempts using several chemical agents, placement of intrabladder compression balloon, hyperbaric oxygen treatment, transarterial embolization, or surgery. In view of the differences between patients with regard to the causes of bleeding, immediate treatment options, availability of the treatment modalities in each institution, life expectancy of the patient, and accompanying comorbidities, the management of each patient should be arranged individually. Nevertheless, based on the current literature, a treatment algorithm may be developed for these patients. The first step would be intravesical irrigation with substances with few side effects or intravesical balloon pressure treatment. If this treatment does not yield the expected result, hyperbaric oxygen therapy may be conducted in hemorrhagic cystitis or radiation cystitis patients; otherwise, transarterial embolization, the efficacy and safety of which are well-reported, should be performed. In these patients, application of surgical techniques and intravesical formalin are the last resorts.Current Bladder Dysfunction Reports 12/2011; 6(4). DOI:10.1007/s11884-011-0106-7
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ABSTRACT: Since its discovery approximately 200 years ago, chitosan, as a cationic natural polymer, has been widely used as a topical dressing in wound management owing to its hemostatic, stimulation of healing, antimicrobial, nontoxic, biocompatible and biodegradable properties. This article covers the antimicrobial and wound-healing effects of chitosan, as well as its derivatives and complexes, and its use as a vehicle to deliver biopharmaceuticals, antimicrobials and growth factors into tissue. Studies covering applications of chitosan in wounds and burns can be classified into in vitro, animal and clinical studies. Chitosan preparations are classified into native chitosan, chitosan formulations, complexes and derivatives with other substances. Chitosan can be used to prevent or treat wound and burn infections not only because of its intrinsic antimicrobial properties, but also by virtue of its ability to deliver extrinsic antimicrobial agents to wounds and burns. It can also be used as a slow-release drug-delivery vehicle for growth factors to improve wound healing. The large number of publications in this area suggests that chitosan will continue to be an important agent in the management of wounds and burns.Expert Review of Anticancer Therapy 07/2011; 9(7):857-79. DOI:10.1586/eri.11.59 · 3.06 Impact Factor