Segmental <Emphasis Type="Italic">vs.</Emphasis> Extended Colectomy: Measurable Differences in Morbidity,Function, and Quality of Life

Purpose  The colon coordinates fecal elimination while reabsorbing excess fluid. Extended colonic resection removes synchronous and prevents metachronous disease but may adversely alter bowel function and health-related quality of life to a greater degree than segmental resection. This study examined the short-term morbidity and long-term function and quality of life after colon resections of different extents. Methods  Patients undergoing extended resections (n = 201, subtotal colectomy with ileosigmoid or total abdominal colectomy with ileorectal anastomosis) and segmental colonic resections (n = 321) during 1991 to 2003 were reviewed for perioperative outcomes and surveyed for bowel function and quality of life using an institutional questionnaire and a validated quality of life instrument (response rate: 70 percent). Results  The most common indication for extended resections was multiple polyps, and for segmental resections, single malignancy. The complication-free rate was 75.4 percent after segmental resections, 42.8 percent after ileosigmoid anastomosis, and 60 percent after ileorectal anastomosis. Median daily stool frequency was two after segmental resections, four after ileosigmoid anastomosis, and five after ileorectal anastomosis, despite considerable dietary restrictions (55.6 percent) and medication use (19.6 percent daily) after ileorectal anastomosis. Significant proportions of patients felt restricted from preoperative social activity (31.5 percent), housework (20.4 percent), recreation (31.5 percent), and travel (42.6 percent) after ileorectal anastomosis. The overall quality of life after segmental resection, ileosigmoid anastomosis, and ileorectal anastomosis was 98.5, 94.9, and 91.2, respectively. Conclusions  Measurable compromises in long-term bowel function and quality of life were observed after extended vs. segmental resections. The relative differences in patient-related outcomes should be deliberated against the clinical benefits of extended resection for the individual patient. Presented at the Tripartite Colorectal Meeting, Dublin, Ireland, July 5 to 7, 2005.     

Impact of Pelvic Radiotherapy on Morbidity and Durability of Sphincter Preservation After Coloanal Anastomosis for Rectal Cancers

Purpose This study was designed to assess the impact of pelvic radiotherapy on the incidence of complications and colostomy-free survival of patients after a coloanal anastomosis for rectal cancer. Methods A total of 192 patients underwent a coloanal anastomosis between 1982 and 2001: 87 patients did not receive pelvic radiotherapy; 105 patients received pelvic radiotherapy (39 preoperative and 66 postoperative). Early and late complications requiring surgical intervention and the colostomy-free survival rate were assessed by retrospective review of patient records. Results After a median follow-up of 62 months, 151 patients were alive. The most frequent complication was development of an anastomotic stricture (5-year rate of a stricture, 16 percent; 95 percent confidence interval, 10–21). Patients receiving pelvic radiotherapy had a higher rate of complications other than anastomotic strictures, including fecal incontinence, fistulas, abscesses, and bowel obstructions compared with patients not receiving pelvic radiotherapy (5-year rate: 20 percent (95 percent confidence interval, 10–29) vs. 5 percent (95 percent confidence interval, 0–10); P = 0.001). Patients receiving pelvic radiotherapy had a lower colostomy-free survival than did patients not receiving pelvic radiotherapy (5-year colostomy-free rate: 72 percent (95 percent confidence interval, 62–84) vs. 92 percent (95 percent confidence interval, 86–98); P < 0.001). There was no significant difference in the colostomy-free survival of patients receiving preoperative and postoperative pelvic radiotherapy. Conclusions After coloanal anastomosis, a significant number of patients will have complications requiring surgical intervention, and some will require a permanent colostomy. Pelvic radiotherapy, whether it is administered preoperatively or postoperatively, significantly increases the need for a permanent colostomy.     

Photochemotherapeutic Strategy against Acanthamoeba Infections

Acanthamoeba is a protist pathogen that can cause serious human infections, including blinding keratitis and a granulomatous amoebic encephalitis that almost always results in death. The current treatment for these infections includes a mixture of drugs, and even then, a recurrence can occur. Photochemotherapy has shown promise in the treatment of Acanthamoeba infections; however, the selective targeting of pathogenic Acanthamoeba has remained a major concern. The mannose-binding protein is an important adhesin expressed on the surface membranes of pathogenic Acanthamoeba organisms. To specifically target Acanthamoeba, the overall aim of this study was to synthesize a photosensitizing compound (porphyrin) conjugated with mannose and test its efficacy in vitro. The synthesis of mannose-conjugated porphyrin was achieved by mixing benzaldehyde and pyrrole, yielding tetraphenylporphyrin. Tetraphenylporphyrin was then converted into mono-nitrophenylporphyrin by selectively nitrating the para position of the phenyl rings, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. The mono-nitrophenylporphyrin was reduced to mono-aminophenylporphyrin in the presence of tin dichloride and confirmed by a peak at m/z 629. Finally, mono-aminoporphyrin was conjugated with mannose, resulting in the formation of an imine bond. Mannose-conjugated porphyrin was confirmed through spectroscopic analysis and showed that it absorbed light of wavelengths ranging from 425 to 475 nm. To determine the antiacanthamoebic effects of the derived product, amoebae were incubated with mannose-conjugated porphyrin for 1 h and washed 3 times to remove extracellular compound. Next, the amoebae were exposed to light of the appropriate wavelength for 1 h. The results revealed that mannose-conjugated porphyrin produced potent trophicidal effects and blocked excystation. In contrast, Acanthamoeba castellanii incubated with mannose alone and porphyrin alone did not exhibit an antiamoebic effect. Consistently, pretreatment with mannose-conjugated porphyrin reduced the A. castellanii-mediated host cell cytotoxicity from 97% to 4.9%. In contrast, treatment with porphyrin, mannose, or solvent alone had no protective effects on the host cells. These data suggest that mannose-conjugated porphyrin has application for the targeted photodynamic therapy of Acanthamoeba infections and may serve as a model in the development of therapeutic interventions against other eukaryotic infections.     

Chlorophyll derivatives can be an efficient weapon in the fight against dengue

Dengue, a mosquito-borne viral infection, is one of the major public health concerns in the tropical and subtropical regions of the world. Approximately, 2.5 billion people across the world are at risk from dengue and 50 to 100 million new infections of dengue occur annually. There is yet no vaccine or medicine available against dengue, and treatment remains only supportive. Targeting its vector by a combination of biological and chemical approaches and management of breeding sites are currently the only existing approaches to control or eliminate dengue. Chlorophyll derivatives like chlorophyllin and pheophorbide have been reported as effective natural photosensitizers against larvae of several insects including flies. Chlorophyll derivatives were also reported effective against larval stages of freshwater snails as well as against certain parasites of fish. This article briefly discusses the possible application of chlorophyll derivatives in controlling dengue vectors and hence the disease itself. Chlorophyll derivatives can prove to be a good contributor in an integrated approach against dengue.     

A bi-functional hepatitis B virus core antigen (HBcAg) chimera activates HBcAg-specific T cells and preS1-specific antibodies

A major problem in chronic hepatitis B virus (HBV) infection is that treatment with specific antivirals is life-long since they rarely induce a sustained response. An attractive option is therefore to combine antiviral therapy with some type of immune stimulator, such as a therapeutic vaccine. Several lines of evidence suggest that a key target for the cellular immune response is the HBV core antigen (HBcAg). However, it may also be of advantage to simultaneously improve the neutralizing antibody response to the surface (S) region of HBV. We therefore generated chimeric HBcAg particles expressing preS1 residues 1-42 at the tip of the spike region. We could show that this chimeric HBcAg-preS1 protein primed both HBcAg-specific T cells and antibodies to preS1. This strongly suggests that this may be a viable approach to develop an effective bi-functional therapeutic vaccine as an add-on for the treatment of chronic HBV infections.     

Predictors of prolonged survival after allogeneic hematopoietic stem cell transplantation for multiple myeloma

A total of 149 patients with multiple myeloma (MM) who received allogeneic hematopoietic stem cell transplantation (allo-HCT) with myeloablative (MAC; n = 38) or reduced-intensity conditioning (RIC; n = 110) regimens at MD Anderson Cancer Center were evaluated. Of the total, 120 (81%) patients had relapsed or had refractory disease. Median age of MM patients was 50 (28-70) years with a followup time of 28.5 (3-164) months. The 100-day and 5-year treatment related mortality (TRM) rates were 17% and 47%, respectively. TRM was significantly lower with RIC regimens (13%) vs. 29% for MAC at 100 days (P = 0.012). The cumulative incidence of Grade II-IV acute graft-versus-host disease (GVHD) was 35% and chronic GVHD was 46%. PFS and OS at 5 years were 15% and 21%, respectively. In multivariate analysis, allo-HCT for primary remission consolidation was associated with longer PFS (HR 0.35; 95% CI, 0.18-0.67) and OS (HR 0.29; 95% CI 0.15-0.55), while absence of high-risk cytogenetics was associated with longer PFS only (HR 0.59; 95% CI 0.37-0.95). We observe that TRM has decreased with the use of RIC regimens, and long-term disease control can be expected in a subset of MM patients undergoing allo-HCT. Further studies should be conducted in carefully designed clinical trials in this patient population.     

The formation of an organic coat and the release of corrosion microparticles from metallic magnesium implants

Magnesium alloys have been proposed as prospective degradable implant materials. To elucidate the complex interactions between the corroding implants and the tissue, magnesium implants were analyzed in a mouse model and the response was compared to that induced by Ti and by the resorbable polymer polyglactin, respectively. One month after implantation, distinct traces of corrosion were apparent but the magnesium implants were still intact, whereas resorbable polymeric wound suture implants were already fragmented. Analysis of magnesium implants 2 weeks after implantation by energy-dispersive X-ray spectroscopy indicated that magnesium, oxygen, calcium and phosphate were present at the implant surface. One month after implantation, the element composition of the outermost layer of the implant was indicative of tissue without detectable levels of magnesium, indicating a protective barrier function of this organic layer. In agreement with this notion, gene expression patterns in the surrounding tissue were highly similar for all implant materials investigated. However, high-resolution imaging using energy-filtered transmission electron microscopy revealed magnesium-containing microparticles in the tissue in the proximity of the implant. The release of such corrosion particles may contribute to the accumulation of calcium phosphate in the nearby tissue and to bone conductive activities of magnesium implants.