Antimycobacterial compound of chitosan and ethambutol: ultrastructural biological evaluation in vitro against Mycobacterium tuberculosis.

Chitosan (CS) is a promising biopolymer and has been tested as a complement to the action and compensation of toxicity presented by anti-tuberculosis drugs. The present work studied the adjuvant effect of CS with the drug ethambutol (EMB) as a compound (CS-EMB), to explore its antimicrobial and cytotoxic activity, using transmission electron microscopy (TEM), to examine ultracellular changes that represent possible antimycobacterial action of CS on Mycobacterium tuberculosis (Mtb). Antimycobacterial activities were tested against reference strains Mtb ATCC® H37Rv and multidrug resistant (MDR). In vitro cytotoxicity tests were performed on Raw 264.7. For the studied compounds, morphological, ultrastructural, and physical-chemical analyses were performed. Drug-polymer interactions that occur through the H bridges were confirmed by physical-chemical analyses. The CS-EMB compound is stable at pHs of 6.5-7.5, allowing its release at physiological pH. The antibacterial activity (minimum inhibitory concentration) of the CS-EMB compound was 50% greater than that of the EMB in the H37Rv and MDR strains and the ultrastructural changes in the bacilli observed by TEM proved that the CS-EMB compound has a bactericidal action, allowing it to break down the Mtb cell wall. The cytotoxicity of CS-EMB was higher than that of isolated EMB, IC50 279, and 176 µg/mL, respectively. It is concluded that CS-EMB forms a promising composite against strains Mtb H37Rv and multidrug resistant (MDR-TB).Key points• Our study will be the first to observe ultrastructurally the effects of the CS-EMB compound on Mtb cells.• CS-EMB antimicrobial activity in a multidrug-resistant clinical strain.• The CS-EMB compound has promising potential for the development of a new drug to fight tuberculosis.

Seasonal variation of bacterial communities in shellfish harvesting waters: preliminary study before applying phage therapy.

The recurrent emergence of infections outbreaks associated with shellfish consumption is an important health problem, which results in substantial economic losses to the seafood industry. Even after depuration, shellfish is still involved in outbreaks caused by pathogenic bacteria, which increases the demand for new efficient strategies to control the shellfish infection transmission. Phage therapy during the shellfish depuration is a promising approach, but its success depends on a detailed understanding of the dynamics of bacterial communities in the harvesting waters. This study intends to evaluate the seasonal dynamics of the overall bacterial communities, disease-causing bacterial populations and bacterial sanitary quality indicators in two authorized harvesting-zones at Ria de Aveiro. During the hot season, the total bacterial community presented high complexity and new prevalent populations of the main shellfish pathogenic bacteria emerged. These results indicate that the spring/summer season is a critical period during which phage therapy should be applied.

Phage therapy to control multidrug-resistant Pseudomonas aeruginosa skin infections: in vitro and ex vivo experiments.

The main goal of this study was to evaluate the efficiency of phage therapy against one of the most common multidrug-resistant (MDR) agents of skin infections, Pseudomonas aeruginosa. A phage suspension [10(8) plaque-forming units (PFU) mL(-1)] was obtained using the clinical strain P. aeruginosa 709 as the host. The ability of the phage to inactivate P. aeruginosa was evaluated in vitro and ex vivo (human skin), using a multiplicity of infection (MOI) of 0.5 to 50. In the presence of the phage, the density of P. aeruginosa 709 [10(5) colony-forming units (CFU) mL(-1)] in the human skin decreased by 4 logs after 2 h of incubation. The application of a second dose of phage did not increase the efficiency of the therapy. This study indicates that the topical application of phage PA709 efficiently inactivates MDR P. aeruginosa 709. The high efficiency in the inactivation of MDR P. aeruginosa 709, its considerable host range (infection of 30 % of the P. aeruginosa isolates) and its high stability in buffer and ex vivo human skin make this phage very promising for the treatment of P. aeruginosa skin infections. The phage-bacteria interactions were examined in vitro and in ex vivo in order to provide a basis for the selection of the most suitable protocol for subsequent in vivo experiments.

The efficacy of laparoscopy in acute cholecystitis.

OBJECTIVE: To evaluate the role of laparoscopic cholecystectomy in acute cholecystitis and establish the outcomes of this treatment modality at North Oakland Medical Centers. METHODS: This was a retrospective analysis over a three-year period (January 1, 1994 to December 31, 1996), performed at a University-affiliated urban teaching hospital, North Oakland Medical Centers, Pontiac, Michigan. Five hundred and fifty-seven patients underwent surgical treatment for gallbladder disease; 88 patients had acute cholecystitis, and 469 patients had chronic cholecystitis. Acute cholecystitis patients underwent surgery within 72 hours of the onset of symptoms; the patient's selection for laparoscopic cholecystectomy or open cholecystectomy depended on severity of disease, co-morbid factors and surgeon's preference. The parameters of age, gender, operating (OR) time, length of stay, complications, conversion rates from laparoscopic cholecystectomy to open cholecystectomy, and cost were compared in patients who underwent laparoscopic cholecystectomy and/or open cholecystectomy. RESULTS: Patients chosen to undergo laparoscopic cholecystectomy for acute cholecystitis tended to be younger females. Patients treated with laparoscopic cholecystectomy for acute cholecystitis had shorter OR times and LOS compared to patients treated with open cholecystectomy for acute cholecystitis. Conversion rates (CR) were 22% in acute cholecystitis and 5.5% in chronic cholecystitis during the study period; CR diminished considerably between the first and third year. Complications were also lower in patients who underwent laparoscopic cholecystectomy vs. open cholecystectomy. CONCLUSIONS: Laparoscopic cholecystectomy appears to be a reliable, safe, and cost-effective treatment modality for acute cholecystitis; however, the surgical approach should be cautionary because of the spectrum of potential technical hazards. CR is improving as surgeons gain experience.

Optimal revascularization of segmental pancreatic transplant.

Vascular anastomotic thrombosis is one of the most frequent complications after segmental transplantation of the pancreas (STP). We propose a new type of vascular anastomosis to reduce the rate of vascular thrombosis following STP. For this purpose we used double arterial-double venous anastomosis (DADVA). Four different types of vascular anastomosis used for STP were studied and compared. The rate of vascular anastomotic thrombosis was evaluated in correlation with the type of vascular anastomosis used. Traditional vascular anastomosis (TVA) was complicated by vascular thrombosis in 51.9% of cases. DADVA reduced rate of vascular thrombosis to 2.6% (P < 0.01).

Cyclic guanine monophosphate (cGMP) an intracellular mediator of cavernosal smooth muscle relaxation following penile vascular surgery.

BACKGROUND: We describe a new surgical method for treatment of male impotence. This procedure allows preservation of erectile tissues and avoids the need for implantable devices. It was demonstrated, that after this procedure sustained and reproducible erections were feasible. The role of cyclic guanine monophosphate (cGMP) in generation of erection following this procedure was studied. METHODS: Concentration of cGMP in erectile tissues was studied in the chronic canine experimental model. cGMP measurements were obtained using enzymeimmunoassay method. RESULTS: It was detected that the process of erection was accompanied with increased concentration of cGMP in the involved erectile structures (from 39.59 +/- 8.95 and 39.39 +/- 8.54 pm/g to 78.67 +/- 24.05 and 81.62 +/- 18.80 pm/g respectively with p = 0.0001). Concentration of cGMP did not change in the control (from 41.14 +/- 5.38 to 39.26 +/- 7.59 pm/g with p = 0.4568). CONCLUSION: It can be concluded, that proposed new surgical procedure causes erection not by simple distention of erectile tissue sinuses by arterial blood. Arterial blood inflow is accompanied by activation of intracellular mechanisms responsible for smooth muscle relaxation in erectile tissues. Normal values of cGMP concentration in canine erectile tissues are also reported.

Blood flow in the pancreatic segment before and after transplantation.

BACKGROUND: Blood flow in the pancreas before and after transplantation has not been studied sufficiently. Blood flow in the pancreatic transplant as a function of type vascular anastomosis used has not been explored. AIM: The objective of our study was to study blood flow in the intact pancreas prior to harvesting and at different time periods after transplantation. Two different types of vascular anastomosis were used for segmental transplantation of the pancreas. Blood flow in the transplanted pancreas was compared in this two experimental groups. METHODS: Study was conducted on 61 mongrel dogs. Autotransplantation of a pancreatic segment was performed to the left iliac vessels. There were two randomized experimental groups. In the first group (26 animals) traditional vascular anastomosis was used to revascularize pancreatic graft. Proximal end of splenic artery was anastomosed to iliac artery in "end to side" manner. Portal end of splenic vein was anastomosed to iliac vein in "end to side" manner as well. Splenic ends of splenic artery and vein were ligated. In the second group (35 animals) double arterial double venous anastomosis was used. For this purpose, after completing traditional vascular anastomosis, second arterial anastomosis was created distal to the first one between distal end of splenic artery and iliac artery in "end to side" fashion. Second venous anastomosis was performed distal to the first one between splenic end of splenic vein and iliac vein in "end to side" fashion. Blood flow in the pancreatic segment was measured using direct blood flow measurement method and electromagnetic flowmetry. After transplantation of pancreatic segment, blood flow was measured in the pancreatic graft 3 min, 1 h, 1 and 6 months following transplantation. RESULTS: Blood flow in the pancreas before harvesting was 0.69 +/- 0.01 ml/min/g. Blood flow in the pancreatic transplant in traditional vascular anastomosis group was higher than blood flow in the normal pancreas (1.13 +/- 0.05 ml/min/g after one month and 1.00 +/- 0.05 ml/min/g after six months (p < 0.01)). Blood flow in the double arterial double venous anastomosis group was not statistically significantly different from blood flow in the normal pancreas at 1 and 6 months after transplantation (0.70 +/- 0.02 and 0.67 +/- 0.02 ml/min/g accordingly). CONCLUSION: Double arterial double venous anastomosis provided more physiological blood flow to the graft, than traditional vascular anastomosis.

Serum levels of interleukin 1 and tumor necrosis factor alpha correlate with peritoneal adhesion grades in humans after major abdominal surgery.

Peritoneal adhesions are a leading cause of potential morbidity and mortality. We undertook this prospective study to determine the clinical relevance of interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) levels as biological markers for peritoneal adhesion formation in humans. Fifteen patients who had previous colectomies and were undergoing re-exploration for an elective vascular procedure were studied. Blood samples were collected from each patient preoperatively and 30 minutes after the abdominal incision was made. Serum levels of IL-1 and TNF-alpha were determined using enzyme-linked immunosorbent assay kits. Adhesions were graded using an adhesion scale of 0 (none), 1 (mild), 2 (moderate), and 3 (extensive, dense). Preoperative levels of IL-1 and TNF-alpha did not differ significantly among all patients (IL-1 level was 60 +/- 14 pg/mL, and TNF-alpha level was 45 +/- 11 pg/mL; mean +/- standard deviation). Significant correlation was observed between grades of adhesions and early intraoperative levels of IL-1 [101 +/- 36 pg/mL for grade 1 (n = 8) vs 298 +/- 73 pg/mL for grade 3 (n = 6); P < 0.01] and TNF-alpha (88 +/- 23 pg/mL for grade 1 vs 261 +/- 88 mL for grade 3; P < 0.02). We conclude that early elevations of IL-1 and TNF-alpha are reliable biological markers for postoperative adhesions in humans. Studies utilizing cytokines antibodies to these markers may further elucidate the efficacy of this method for prevention of peritoneal adhesions.

Gastrosplenic fistulas: a case report and review of the literature.

A case is presented of a patient who developed a gastrosplenic fistula during a course of chemotherapy for differentiated histiocytic lymphoma. The fistula was observed during upper gastrointestinal endoscopy (gastroscopy) and confirmed by CT scan with contrast. The fistula was followed endoscopically and noted to have closed spontaneously with confirmed closure at laparotomy. The clinical management of this complication is discussed, and the literature pertaining to this rare condition is reviewed.

Effects of interleukin-6 and its neutralizing antibodies on peritoneal adhesion formation and wound healing.

This study investigates the effects of preoperative IV administration of IL-6 and anti IL-6 on peritoneal adhesion formation and wound healing. Thirty-six male Sprague-Dawley rats (350-400 mg) were divided into three groups: control (group 1); IL-6 (group 2); and anti IL-6 (group 3). Under sterile conditions, all rats underwent a midline laparotomy. Ten cm2 of cecal serosa was abraded, the cecum further irritated with 0.1 ml of 70 per cent alcohol, and the incision closed in layers. At 3 weeks, peritoneal adhesions were graded using a score of 0 (none) to 3 (extensive, dense). Skin samples from incisional sites were examined tensiometrically (true stress and true strain), biochemically (collagen content), and histologically. Adhesion formation score was significantly increased in IL-6 group (2.78 +/- 0.44, Mean +/- SD) and decreased in anti IL-6 group (1.40 +/- 0.52) compared to control (2.00 +/- 0.50). (P < 0.03 by Kruskal Wallis test). There was no significant difference in true stress, true strain, and collagen content between the two treatment groups and controls at the 0.05 level by ANOVA. Histological analysis showed higher number of inflammatory cells and fibroblasts in IL-6 treated groups. We conclude that IL-6 plays a major role in peritoneal adhesion formation. Selective immunosuppression, using IL-6 neutralizing antibodies preoperatively, leads to a reduction of such adhesion formation without a significant effect on wound healing.