Risk factors for incisional surgical site infections in elective surgery for colorectal cancer: focus on intraoperative meticulous wound management

Purpose

An incisional surgical site infection (I-SSI) is a frequently observed complication following colorectal surgery. Intraoperative wound management is one of the most important factors that determine the incidence of postoperative I-SSI. The purpose of this study was to assess the impact of the methods used for intraoperative wound management on the incidence of I-SSI following elective surgery for colorectal cancer.

Methods

Between November 2009 and February 2011, the data of 1,980 consecutive patients who underwent elective colorectal resection for colorectal cancer were prospectively collected from 19 affiliated hospitals. The incidence of and risk factors for I-SSI were investigated.

Results

Overall, 233 I-SSIs were identified (11.7 %). Forty-two possible risk factors were analyzed. Using a multivariate analysis, the independent risk factors for I-SSI were identified to be a high body mass index, previous laparotomy, chronic liver disease, wound length, contaminated wound class, creation or closure of an ostomy, right hemicolectomy procedure, the suture material used for fascial closure and the incidence of organ/space SSI.

Conclusion

To prevent I-SSI following elective colorectal surgery, it is crucial to avoid making large incisions and reduce fecal contamination whenever possible. A high quality randomized control trial is necessary to confirm the definitive intraoperative procedure(s) that can minimize the incidence of I-SSI.     

Positional cloning of the gene LIMBIN responsible for bovine chondrodysplastic dwarfism

Chondrodysplastic dwarfism in Japanese brown cattle is an autosomal recessive disorder characterized by short limbs. Previously, we mapped the locus responsible for the disease on the distal end of bovine chromosome 6. Here, we narrowed the critical region to approximately 2 cM by using linkage analysis, constructed a BAC and YAC contig covering this region, and identified a gene, LIMBIN (LBN), that possessed disease-specific mutations in the affected calves. One mutation was a single nucleotide substitution leading to an activation of a cryptic splicing donor site and the other was a one-base deletion resulting in a frameshift mutation. Strong expression of the Lbn gene was observed in limb buds of developing mouse embryos and in proliferating chondrocytes and bone-forming osteoblasts in long bones. These findings indicate that LBN is responsible for bovine chondrodysplastic dwarfism and has a critical role in a skeletal development.     

Recurrent Cholangitis by Biliary Stasis Due to Non-Obstructive Afferent Loop Syndrome After Pylorus-Preserving Pancreatoduodenectomy: Report of a Case

We report a 71-year-old man who had undergone pylorus-preserving pancreatoduodenectomy (PPPD) using PPPD-IV reconstruction for cholangiocarcinoma. For 6 years thereafter, he had suffered recurrent cholangitis, and also a right liver abscess (S5/8), which required percutaneous drainage at 9 years after PPPD. At 16 years after PPPD, he had been admitted to the other hospital because of acute purulent cholangitis. Although medical treatment resolved the cholangitis, the patient was referred to our hospital because of dilatation of the intrahepatic biliary duct (B2). Peroral double-balloon enteroscopy revealed that the diameter of the hepaticojejunostomy anastomosis was 12 mm, and cholangiography detected intrahepatic stones. Lithotripsy was performed using a basket catheter. At 1 year after lithotripsy procedure, the patient is doing well. Hepatobiliary scintigraphy at 60 minutes after intravenous injection demonstrated that deposit of the tracer still remained in the upper afferent loop jejunum. Therefore, we considered that the recurrent cholangitis, liver abscess, and intrahepatic lithiasis have been caused by biliary stasis due to nonobstructive afferent loop syndrome. Biliary retention due to nonobstructive afferent loop syndrome may cause recurrent cholangitis or liver abscess after hepaticojejunostomy, and double-balloon enteroscopy and hepatobiliary scintigraphy are useful for the diagnosis of nonobstructive afferent loop syndrome.Key words: Nonobstructive afferent loop syndrome, Biliary stasis, Hepaticojejunostomy, Hepatobiliary scintigraphy, Double-balloon enteroscopyIt has been reported that cholangitis occurs in between 6.7% and 14.3% of postoperative pancreatoduodenectomy (PD).¹ Most cases of cholangitis originate due to biliary stasis, which is broadly caused by either anastomotic or nonanastomotic stenosis. In many cases, anastomotic stenosis is accompanied by intrahepatic biliary duct dilatation and obstructive jaundice, making early diagnosis and treatment possible.^2–3 On the other hand, nonanastomotic stenosis, including those of afferent loop syndrome, is performed as a conservative treatment for unexplained fever and cholangitis. However, in many cases, the cause remains unidentified, thereby causing this condition to repeat itself. Since cholangitis can at times be fatal, it is therefore important to identify the cause.It has been reported that afferent loop syndrome occurs in around 13% of postoperative PD patients.⁴ Afferent loop syndrome is generally caused by mechanical occlusion due to the recurrence or metastasis of cancer,^4–6 adhesion,^7–8 torsion,⁹ internal hernia,¹⁰ enterolithiasis,^11–12 etc., and thereafter, leads to a syndrome associated with acute abdominal symptom or acute cholangitis. On the other hand, nonobstructive afferent loop syndrome may also be caused by biliary stasis due to jejunal motility failure or the length of the blind end or jejunum, and thereafter, leads to acute cholangitis, liver abscess, and the formation of enterolithiasis and intrahepatic stones. Nonobstructive afferent loop syndrome occurs in around 37% of all of the afferent loop syndrome,^12–13 but few cases have actually been reported.We herein report a rare case in which the patient experienced recurrent cholangitis and liver abscess by biliary stasis due to nonobstructive afferent loop syndrome after pylorus-preserving pancreatoduodenectomy (PPPD) for cholangiocarcinoma.     

Changing the mind? Not really—activity and connectivity in the caudate correlates with changes of choice

Changes in preference are inherently subjective and internal psychological events. We have identified brain events that presage ultimate (rather than intervening) choices, and signal the finality of a choice. At the first exposure to a pair of faces, caudate activity reflected the face of final choice, even if an initial choice was different. Furthermore, the orbitofrontal cortex and hippocampus exhibited correlations only when the subject had made a choice that would not change.     

From the Cover: Form of an evolutionary tradeoff affects eco-evolutionary dynamics in a predator–prey system

Evolution on a time scale similar to ecological dynamics has been increasingly recognized for the last three decades. Selection mediated by ecological interactions can change heritable phenotypic variation (i.e., evolution), and evolution of traits, in turn, can affect ecological interactions. Hence, ecological and evolutionary dynamics can be tightly linked and important to predict future dynamics, but our understanding of eco-evolutionary dynamics is still in its infancy and there is a significant gap between theoretical predictions and empirical tests. Empirical studies have demonstrated that the presence of genetic variation can dramatically change ecological dynamics, whereas theoretical studies predict that eco-evolutionary dynamics depend on the details of the genetic variation, such as the form of a tradeoff among genotypes, which can be more important than the presence or absence of the genetic variation. Using a predator–prey (rotifer–algal) experimental system in laboratory microcosms, we studied how different forms of a tradeoff between prey defense and growth affect eco-evolutionary dynamics. Our experimental results show for the first time to our knowledge that different forms of the tradeoff produce remarkably divergent eco-evolutionary dynamics, including near fixation, near extinction, and coexistence of algal genotypes, with quantitatively different population dynamics. A mathematical model, parameterized from completely independent experiments, explains the observed dynamics. The results suggest that knowing the details of heritable trait variation and covariation within a population is essential for understanding how evolution and ecology will interact and what form of eco-evolutionary dynamics will result.Evolutionary dynamics, changes in intraspecific genotype frequency over generations, can have a time scale similar to that of ecological dynamics (1–3). Selection mediated by ecological interactions causes evolutionary dynamics, and evolution of traits, in turn, changes ecological interactions. Thus, understanding population dynamics needs to take account of the feedbacks between trait evolution and ecological interactions (i.e., eco-evolutionary feedbacks). These feedbacks have increasingly attracted ecologists’ attention since Pimentel (4) proposed genetic feedback as a mechanism regulating animal populations (e.g., refs. 5–11). This integration of evolutionary biology and ecology has important implications in both basic and applied problems in biology (12–17).Empirical studies have shown that rapid evolution can affect many ecological interactions, including predator–prey (18–20), host–parasite (21), herbivore–plant (22), competitive interactions (23), and interactions with abiotic environments (24–27). Previous empirical studies on eco-evolutionary feedbacks have usually compared the dynamics of populations with and without genetic variation, but recent theoretical models predicted that not only the presence or absence of genetic variation (28–30) but also the form of the evolutionary tradeoff among genotypes is important in generating qualitatively different dynamics (31–35). Indeed, the forms of evolutionary tradeoffs within populations are known to be remarkably variable in plants and microbes (36–38). Thus, there should be various eco-evolutionary dynamics depending on the form of evolutionary tradeoffs existing in wild populations. Nevertheless, to our knowledge, no empirical study has directly demonstrated the theoretically predicted effects of the evolutionary tradeoff on eco-evolutionary dynamics, and it is still unclear how different forms of an evolutionary tradeoff in real organisms can result in different eco-evolutionary dynamics.Here, using a predator–prey (rotifer–algal) system cultured in continuous flow-through microcosms (chemostats), we examined how different forms of an evolutionary tradeoff between defense and growth in algal prey (Chlorella vulgaris) affect the population dynamics of the predator–prey system and the evolutionary changes in the clonal frequency of the algal prey. Experimental studies using laboratory microcosms have been a powerful approach in exploring eco-evolutionary dynamics and testing theoretical predictions because of the constant environment and simple community structure (39–41). We used two different pairs of algal clones originally obtained from the University of Texas (UTEX) algal collection that showed different forms of a fitness tradeoff between antipredator defense and competitive ability to obtain the resource limiting population growth in the experimental system (inorganic nitrogen). Each pair of algal clones was cultured with an obligately asexual lineage of rotifer predators (Brachionus calyciflorus). Population dynamics of the predators and prey and clonal frequency changes in the algal pair were observed in long-term chemostat runs. We recorded evolutionary dynamics (genotype frequency change) by using an allele-specific quantitative PCR (AsQ-PCR) technique based on microsatellite DNA that allowed us to measure the relative abundance of algal clones (42). We also developed a mathematical model for the experimental system, based on a model of Jones and Ellner (43), parameterized the model using data from separate experiments, and compared the model’s predictions to the observed population and genotype dynamics.     

Enteral metallic stenting by balloon enteroscopy for obstruction of surgically reconstructed intestine

We present three cases of self-expandable metallic stent (SEMS) placement using a balloon enteroscope (BE) and its overtube (OT) for malignant obstruction of surgically reconstructed intestine. A BE is effective for the insertion of an endoscope into the deep bowel. However, SEMS placement is impossible through the working channel, because the working channel of BE is too small and too long for the stent device. Therefore, we used a technique in which the BE is inserted as far as the stenotic area; thereafter, the BE is removed, leaving only the OT, and then the stent is placed by inserting the stent device through the OT. In the present three cases, a modification of this technique resulted in the successful placement of the SEMS for obstruction of surgically reconstructed intestine, and the procedures were performed without serious complications. We consider that the present procedure is extremely effective as a palliative treatment for distal bowel stenosis, such as in the surgically reconstructed intestine.     

Virulent influenza A viruses induce apoptosis in chickens

Virulent avian influenza A viruses produce lethal disease in chickens. Since cell death can be caused by either necrosis or apoptosis, we investigated the types of cell death that occur in natural hosts, chickens, infected with virulent avian viruses. Using biochemical methods, we demonstrate that virulent avian influenza viruses induce apoptosis of vascular endothelial cells in liver, kidney, and brain. Viral antigens were also detected in these organs, suggesting that viral replication induces apoptosis in infected chickens. These results indicate that apoptosis does occur in virulent avian influenza virus infection in a natural host, and may contribute to the lethality of the virus.     

Low-risk profile for cardiovascular disease and mortality in Japanese.

BACKGROUND: Some studies focusing on low-risk profiles for cardiovascular disease have been reported in Western countries. Yet, few reports have examined, with substantial longevity, the low-risk profile for cardiovascular disease in the Japanese population. This study examines whether having a favorable risk factor profile yields lower all-cause mortality and whether the proportion of those with a low-risk profile is larger in the Japanese population. METHODS AND RESULTS: A total of 8,339 men and women aged 30-69 years without a history of cardiovascular diseases for 19 years, who had participated in the 1980 National Survey on Circulatory Disorders after being randomly selected from throughout Japan, were followed. Low risk was defined as having all of the following baseline characteristics: blood pressure (BP) <120/80 mmHg; no antihypertensive medication; serum cholesterol 160-240 mg/dl (4.14-6.22 mmol/L); no history of diabetes; and non-smoker. The long-term mortality of the low-risk group was compared with that of others using the Cox proportional hazard model. The prevalence of low risk was 9.4% of all participants. The multivariate-adjusted hazard ratios for low-risk individuals compared with others were as follows: 0.33 (95% confidence intervals (CI), 0.15-0.74) for cardiovascular disease and 0.63 (95% CI, 0.46-0.88) for all-cause mortality. The most attributable risk factor for all-cause mortality was high BP (>or=120/80 mmHg). CONCLUSION: Japanese individuals with favorable cardiovascular disease risk profiles had lower mortality from cardiovascular disease and all-causes than those without.