Influence of the bile acid/microbiota axis in ileal surgery: a systematic review.

AIM: The gastrointestinal bile acid (BA)/microbiota axis has emerged as a potential mediator of health and disease, particularly in relation to pathologies such as inflammatory bowel disease (IBD) and colorectal cancer. Whilst it presents an exciting new avenue for therapies, it has not yet been characterized in surgical resection of the ileum, where BA reabsorption occurs. The identification of BA/microbiota signatures may provide future therapies with perioperative personalized medicine. In this work we conduct a systematic review with the aim of investigating the microbiome and BA changes that are associated with resection of the ileum. METHOD: The databases included were MEDLINE, EMBASE, Web of Science and Cochrane libraries. The outcomes of interest were faecal microbiome and BA signatures after ileal resection. RESULTS: Of the initial 3106 articles, three studies met the inclusion/exclusion criteria for data extraction. A total of 257 patients (46% surgery, 54% nonsurgery controls) were included in the three studies. Two studies included patients with short bowel syndrome and the other included patients with IBD. Large-scale microbiota changes were reported. In general, alpha diversity had decreased amongst patients with ileal surgery. Phylum-level changes included decreased Bacteroidetes and increased Proteobacteria and Fusobacteria in patients with an intestinal resection. Surgery was associated with increased total faecal BAs, cholic acid and chenodeoxycholic acid. There were decreases in deoxycholic acid and glycine and taurine conjugated bile salts. Integrated BA and microbiota data identified correlations with several bacterial families and BA. CONCLUSION: The BA/microbiota axis is still a novel area with minimal observational data in surgery. Further mechanistic research is necessary to further explore this and identify its role in improving perioperative outcomes.

Topical Lidocaine or Lidocaine/Diltiazem Ointment Following Rubber Band Ligation of Hemorrhoids: A Prospective 3-Armed Randomized Controlled Trial.

BACKGROUND: Rubber band ligation of hemorrhoids causes less pain than excisional hemorrhoidectomy, but many patients still experience significant postprocedure discomfort. OBJECTIVE: This study aimed to determine whether topical lidocaine, with or without diltiazem, is more effective than placebo for analgesia after hemorrhoid banding. DESIGN: This is a prospective, randomized, double-blinded, placebo-controlled trial. Patients were randomly assigned to 2% lidocaine, 2% lidocaine with 2% diltiazem, or a placebo ointment. SETTINGS: This study was performed at 2 university public teaching hospitals and 2 private hospitals in Australia. PATIENTS: Consecutive patients aged ≥18 years undergoing hemorrhoid banding were selected. INTERVENTIONS: Topical ointments were applied postprocedure 3× daily for 5 days. MAIN OUTCOME MEASURES: Visual analog pain score, opiate analgesia usage, and patient satisfaction were the main outcome measures. RESULTS: Of 159 eligible patients, 99 were randomly assigned (33 in each group). Pain scores were reduced at 1 hour for the lidocaine (OR 4.15 [1.12-15.41]; p = 0.03) and lidocaine/diltiazem groups (OR 3.85 [1.05-14.11]; p = 0.04) compared with placebo. Patients in the lidocaine/diltiazem group had improved satisfaction (OR 3.82 [1.28-11.44]; p = 0.02) and were more likely to recommend the procedure to others (OR 9.33 [1.07-81.72]; p = 0.04). Patients in the lidocaine/diltiazem group required approximately 45% less total and in-hospital analgesia compared with the placebo. There was no difference in complications between any of the groups. LIMITATIONS: A cost/benefit analysis was not performed. Analgesic efficacy appeared to be short term and the procedures were performed only in the hospital/nonambulatory setting. CONCLUSIONS: Topical lidocaine reduced short-term analgesia use, whereas combination lidocaine/diltiazem was associated with both improved analgesia and patient satisfaction after hemorrhoid banding. LIDOCANA TPICA O UNGENTO DE LIDOCANA/DILTIAZEM DESPUS DE LA LIGADURA HEMORROIDAL CON BANDA ELSTICA UN ENSAYO PROSPECTIVO CONTROLADO Y ALEATORIZADO DE TRES BRAZOS: ANTECEDENTES:La ligadura de hemorroides con banda elástica causa menos dolor que la hemorroidectomía escisional, pero muchos pacientes siguen experimentando molestias significativas tras el procedimiento.OBJETIVO:Este estudio tiene como objetivo determinar si la lidocaína tópica, con o sin diltiazem, es más eficaz que el placebo para la analgesia tras la ligadura hemorroidal.DISEÑO:Este es un ensayo prospectivo, aleatorizado, doble ciego, controlado con placebo. Los pacientes fueron aleatorizados para recibir lidocaína al 2 %, lidocaína al 2 % con diltiazem al 2 % o ungüento de placebo.AJUSTES:Este estudio se realizó en dos hospitales públicos con docencia universitaria y dos hospitales privados en Australia.PACIENTES:Se seleccionaron pacientes consecutivos de ≥18 años sometidos a ligadura para hemorroides.INTERVENCIONES:Se aplicaron ungüentos tópicos tras el procedimiento tres veces al día durante 5 días.PRINCIPALES MEDIDAS DE RESULTADO:La puntuación analógica visual del dolor, el uso de analgésicos opiáceos y la satisfacción del paciente fueron las principales medidas de resultado.RESULTADOS:De 159 pacientes elegibles, 99 fueron aleatorizados (33 en cada grupo). Las puntuaciones de dolor se redujeron a la hora para los grupos de lidocaína (OR 4,15 (1,12-15,41); p = 0,03) y lidocaína/diltiazem (OR 3,85 (1,05-14,11), p = 0,04) en comparación con el placebo.Los pacientes del grupo de lidocaína/diltiazem mejoraron su satisfacción (OR 3,82 (1,28-11,44), p = 0,02) y eran más propensos de recomendar el procedimiento a otros (OR 9,33 (1,07-81,72), p = 0,04). Los pacientes del grupo de lidocaína/diltiazem requirieron aproximadamente un 45 % menos de analgesia total e intrahospitalaria en comparación con el grupo de placebo. No hubo diferencia en las complicaciones entre ninguno de los grupos.LIMITACIONES:No se realizó un análisis de costo/beneficio. La eficacia analgésica pareció ser a corto plazo y los procedimientos solo se realizaron en el hospital/entorno no ambulatorio.CONCLUSIÓN:La lidocaína tópica mejora la analgesia a corto plazo, mientras que la combinación de lidocaína/diltiazem se asocia tanto con una mejor analgesia como con la satisfacción del paciente tras la colocación de bandas para hemorroides. (Traducción-Dr Osvaldo Gauto ).

Venous thromboembolic prophylaxis: current practice of surgeons in Australia and New Zealand for major abdominal surgery.

BACKGROUND: Surgical prophylaxis for venous thrombo-embolic disease (VTE) includes risk assessment, chemical prophylaxis and mechanical prophylaxis (graduated compression stockings [GCS] and/or intermittent pneumatic compression devices [IPCD]). Although there is overwhelming evidence for the need and efficacy of VTE prophylaxis in patients at risk, only about a third of those who are at risk of VTE receive appropriate prophylaxis. OBJECTIVE: There is debate as to the best combination of VTE prophylaxis following abdominal surgery due to lack of evidence. The aim of this survey was to understand this gap between knowledge and practice. METHODS: In 2019 and 2020, a survey was conducted to investigate the current practice of venous thromboembolism (VTE) prophylaxis for major abdominal surgery, with a focus on colorectal resections. The study received ethics approval and involved distributing an 11-item questionnaire to members of two professional surgical societies: the Colorectal Surgical Society of Australia and New Zealand (CSSANZ) and the General Surgeons Australia (GSA). RESULTS: From 214 surgeons: 100% use chemical prophylaxis, 68% do not use a risk assessment tool, 27% do not vary practice according to patient risk factors while > 90% use all three forms of VTE prophylaxis at some stage of treatment. Most surgeons do not vary practice between laparoscopic and open colectomy/major abdominal surgery and only 33% prescribe post-discharge chemical prophylaxis. 42% of surgeons surveyed had equipoise for a clinical trial on the use of IPCDs and the vast majority (> 95%) feel that IPCDs should provide at least a 2% improvement in VTE event rate in order to justify their routine use. CONCLUSION: Most surgeons in Australia and New Zealand do not use risk assessment tools and use all three forms of prophylaxis regardless. Therfore there is a gap between practice and VTE prophylaxis for the use of mechanical prophylaxis options. Further research is required to determine whether dual modality mechanical prophylaxis is incrementally efficacious. Trial Registration- Not Applicable.

Antiseptic Skin Preparation Agents to Prevent Surgical Site Infection in Colorectal Surgery: A 3-Armed Randomized Controlled Trial.

BACKGROUND: There is much debate surrounding the ideal antiseptic skin preparation agent to reduce postoperative surgical site infection. International guidelines suggest that chlorhexidine- and alcohol-containing compounds have superior efficacy. However, there are minimal clinical trials specifically looking at skin preparation agents for colorectal surgery. OBJECTIVE: The aim of this study was to compare the efficacy of chlorhexidine in alcohol versus povidone-iodine in alcohol versus povidone-iodine in aqueous solution for the prevention of surgical site infection in colorectal surgery. DESIGN: This is a prospective, 3-armed, randomized controlled trial. SETTING: This study was conducted at the 800-bed John Hunter Hospital and Newcastle Private Hospital, with all subspecialty services in New South Wales, Australia. PATIENTS: All eligible, consenting adults undergoing colorectal surgery between July 2015 and December 2018 were included. INTERVENTIONS: Patients were andomized to receive preincision skin preparation with one of the following: chlorhexidine in 70% alcohol, povidone-iodine in 70% alcohol, or povidone-iodine in aqueous solution. MAIN OUTCOME MEASURE: The primary measure was surgical site infection within 30 days. RESULTS: A total of 482 patients were randomized to chlorhexidine in alcohol, povidone-iodine in alcohol, or aqueous povidone-iodine. The overall surgical site infection rate was 22% (107/482). There was no difference in rates of surgical site infection: 20.6% (29/141), 22.8% (44/193), and 23.0% (34/148), respectively ( p = 0.5267). There was no difference in complication rates: 54.6% (77/141), 46.1% (89/193), and 49.3% (73/148), respectively ( p = 0.1762). The median length of stay was 6 days in all 3 groups. LIMITATIONS: This is a subset analysis of a larger clinical trial for all forms of incisional surgery (the NewSKIN Prep trial), and noninferiority cannot be assessed. Changes in government regulations resulted in a change from 0.5% chlorhexidine in 70% ethanol to 2% chlorhexidine in 70% ethanol during the trial. CONCLUSION: This large, prospective, randomized clinical trial appears to indicate that there is no difference in surgical site infection, complications, or length of stay among the 3 commonest forms of skin preparation in colorectal surgery. See Video Abstract at http://links.lww.com/DCR/B875 .New Zealand Clinical Trials registry: ACTRN12615000021572Agentes antisépticos para la preparación de la piel para prevenir la infección del sitio quirúrgico en la cirugía colorrectal: un ensayo clínico aleatorizado de tres grupos. ANTECEDENTES: Existe un gran debate en torno al agente de preparación de la piel antiséptico ideal para reducir la infección posoperatoria del sitio quirúrgico. Las pautas internacionales sugieren que los compuestos que contienen clorhexidina y alcohol tienen una eficacia. Sin embargo, existen ensayos clínicos mínimos que analizan específicamente los agentes de preparación de la piel para la cirugía colorrectal. OBJETIVO: Comparar la eficacia de la clorhexidina en alcohol versus povidona yodada en alcohol versus povidona yodada en solución acuosa para la prevención de la infección del sitio quirúrgico en cirugía colorrectal. DISEO: Este es un ensayo controlado aleatorio prospectivo de tres brazos. AJUSTE: Este estudio se realizó en el Hospital John Hunter de 800 camas y el Hospital Privado de Newcastle con todos los servicios de subespecialidad en Nueva Gales del Sur, Australia. PACIENTES: Se incluyeron todos los adultos elegibles que dieron su consentimiento para someterse a una cirugía colorrectal entre julio de 2015 y diciembre de 2018. INTERVENCIONES: Aleatorizados para recibir una preparación para la piel previa a la incisión con uno de: clorhexidina en alcohol al 70%, povidona yodada en alcohol al 70% o povidona yodada en solución acuosa. MEDIDA DE RESULTADO PRINCIPAL: La medida principal fue la infección del sitio quirúrgico dentro de los 30 días. RESULTADOS: Un total de 482 pacientes fueron aleatorizados para recibir clorhexidina en alcohol, povidona yodada en alcohol o povidona yodada acuosa. La tasa global de infección del sitio quirúrgico fue del 22% (107/482). No hubo diferencias en las tasas de infección del sitio quirúrgico; 20,6% (29/141), 22,8% (44/193) y 23,0% (34/148) respectivamente; p = 0,5267. No hubo diferencia en las tasas de complicaciones; 54,6% (77/141), 46,1% (89/193) y 49,3% (73/148) respectivamente; p = 0,1762. La duración media de la estancia hospitalaria fue de 6,0 días en los tres grupos. LIMITACIONES: Este es un análisis de subconjunto de un ensayo clínico más grande para todas las formas de cirugía incisional (el ensayo NewSKIN Prep) y no se puede evaluar la no inferioridad. Los cambios en las regulaciones gubernamentales dieron como resultado un cambio de clorhexidina al 0,5% en etanol al 70% a clorhexidina al 2% en etanol al 70% durante la prueba. CONCLUSINES: Este gran ensayo clínico prospectivo y aleatorizado parece indicar que no hay diferencia en la infección del sitio quirúrgico, las complicaciones o la duración de la estancia entre las 3 formas más comunes de preparación de la piel en la cirugía colorrectal. Consulte Video Resumen en http://links.lww.com/DCR/B875 . (Traducción-Dr. Gonzalo Hagerman )Este ensayo se registró de forma prospectiva en el registro de ensayos clínicos de Australia Nueva Zelanda el 15/01/2015: ACTRN12615000021572.

The link between organic matter composition and the biogas yield of full-scale sewage sludge anaerobic digestion.

The principal parameters influencing anaerobic digestion (AD) of sewage sludge have been extensively studied in controlled laboratory experiments, but the effects of sludge composition on full-scale systems have received relatively little attention. Sludge samples from eight major wastewater treatment plants (WWTPs) in the UK were examined to determine the effects of sludge composition on digestion performance. The biogas yield (BY) was estimated by two different methods: (1) a standard approach based on the reduction in volatile solids (VS), and (2) a more detailed mass balance of major constituent fractions of organic matter in sludge. The results showed that BY increased significantly with the overall amount of VS contained in digester feed sludge. In terms of the effects of individual fractions, BY was significantly related to and increased with the fat and cellulose contents in raw sludge, consistent with the high calorific value of fat and the digestibilities of both substrates, relative to the other major organic components. The results demonstrated the importance of sludge composition on digester performance and strategies to maximise BY were identified, for instance, by increasing codigestion of high fat containing substrates, and by utilising fat, oil and grease collected in-sewer and at WWTP.

A systematic scoping review on natural killer cell function in colorectal cancer.

PURPOSE: Natural Killer (NK) cells are a vital part of immune surveillance and have been implicated in colorectal cancer development and prognosis. This systematic review aims to distil the literature on NK cells as it relates to colorectal cancer. METHODS: All published studies over 10 years relating to NK cells and colorectal cancer were reviewed. All studies publishing in English, searchable via pubmed or through reference review and reporting directly on the nature or function of NK cells in colorectal cancer patients were included. Outcomes were determined as alterations or new information regarding NK cells in colorectal cancer patients. RESULTS: Natural killer cells may be implicated in the development of colorectal cancer and may play a role in prognostication of the disease. NK cells are altered by the treatment (both surgical and medical) of colorectal cancer and it seems likely that they will also be a target for manipulation to improve colorectal cancer survival. CONCLUSIONS: NK cell morphology and function are significantly affected by the development of colorectal cancer. Observation of NK cell changes may lead to earlier detection and better prognostication in colorectal cancer. Further study is needed into immunological manipulation of NK cells which may lead to improved colorectal cancer survival.

Enhancing Distraction Osteogenesis With Carbon Fiber Reinforced Polyether Ether Ketone Bone Pins and a Three-Dimensional Printed Transfer Device to Permit Artifact-Free Three-Dimensional Magnetic Resonance Imaging.

OBJECTIVES: To: (1) design an artifact-free 3D-printed MR-safe temporary transfer device, (2) engineer bone-pins from carbon fiber reinforced polyether ether ketone (CFR-PEEK), (3) evaluate the imaging artifacts of CFR-PEEK, and (4) confirm the osteointegration potential of CFR-PEEK, thus enhancing 3D-planning of bony advancements in hemifacial microsomia using sequential magnetic resonance imaging (MRI). STUDY DESIGN: Engineered CRF-PEEK bone pins and a 3D printed ex-fix device were implanted into a sheep head and imaged with MRI and computed tomography . The osseointegration and bony compatibility potential of CFR-PEEK was assessed with scanning electron microscopy images of MC3T3 preosteoblast cells on the surface of the material. RESULTS: The CFR-PEEK pins resulted in a signal void equivalent to the dimension of the pin, with no adjacent areas of MR-signal loss or computed tomography artifact. MCT3 cells adhered and proliferated on the surface of the discs by forming a monolayer of cells, confirming compatibility and osseointegration potential. CONCLUSION: A 3D printed transfer device could be utilized temporarily during MRI to permit artifact-free 3D planning. CFR-PEEK pins eliminate imaging artifact permitting sequential MRI examination. In combination, this has the potential to enhance distraction osteogenesis, by permitting accurate three-dimensional planning without ionizing radiation.

Systematic Review on the Influence of Tissue Oxygenation on Gut Microbiota and Anastomotic Healing.

BACKGROUND: Anastomotic leak rates have not improved over several decades despite improvements in surgical techniques and patient care. The gut microbiome has been implicated in the development of leaks. The exact mechanisms by which tissue oxygenation affects gut microbial composition and anastomotic healing physiology are unclear. Also, commonly used carbon dioxide (CO2) is a known vasodilator that improves tissue oxygen tension. We performed a systematic review to determine the influence of hyperoxia, hypoxia, and hypercapnia on the gut microbiome and anastomotic healing. METHODS: A literature search was performed in MEDLINE, EMBASE, and COCHRANE to identify studies investigating the effects of hyperoxia, hypoxia, and hypercapnia on anastomotic healing and gut microbiota published between 1998 and 2018. Two reviewers screened the articles for eligibility and quality. Fifty-three articles underwent full text review, and a narrative synthesis was undertaken. RESULTS: Hyperoxia is associated with better anastomotic healing, increased gastrointestinal oxygen tension, and may reduce gut anaerobes. Hypoxia is associated with poor healing and increased gut anaerobes. However, it is unclear if hypoxia is the most important predictor of anastomotic leaks. Low pressure CO2 pneumoperitoneum and mild systemic hypercapnia are both associated with increased gastrointestinal oxygen tension and may improve anastomotic healing. We found no studies which investigated the effect of hypercapnia on gut microbiota in the context of anastomotic healing. CONCLUSIONS: Tissue oxygenation influences gut anastomotic healing, but little evidence exists to demonstrate the influence on the gut microbiome in the context of healing. Further studies are needed to determine if anastomotic microbiome changes with altered tissue oxygenation and if this affects healing and leak rates. If confirmed, altering tissue oxygenation through hyperoxia or hypercapnia could be feasible means of altering the microbiome such that anastomotic leak rates reduce.

Albuminuria and Allograft Failure, Cardiovascular Disease Events, and All-Cause Death in Stable Kidney Transplant Recipients: A Cohort Analysis of the FAVORIT Trial.

RATIONALE & OBJECTIVE: Cardiovascular disease (CVD) is common and overall graft survival is suboptimal among kidney transplant recipients. Although albuminuria is a known risk factor for adverse outcomes among persons with native chronic kidney disease, the relationship of albuminuria with cardiovascular and kidney outcomes in transplant recipients is uncertain. STUDY DESIGN: Post hoc longitudinal cohort analysis of the Folic Acid for Vascular Outcomes Reduction in Transplantation (FAVORIT) Trial. SETTING & PARTICIPANTS: Stable kidney transplant recipients with elevated homocysteine levels from 30 sites in the United States, Canada, and Brazil. PREDICTOR: Urine albumin-creatinine ratio (ACR) at randomization. OUTCOMES: Allograft failure, CVD, and all-cause death. ANALYTICAL APPROACH: Multivariable Cox models adjusted for age; sex; race; randomized treatment allocation; country; systolic and diastolic blood pressure; history of CVD, diabetes, and hypertension; smoking; cholesterol; body mass index; estimated glomerular filtration rate (eGFR); donor type; transplant vintage; medications; and immunosuppression. RESULTS: Among 3,511 participants with complete data, median ACR was 24 (Q1-Q3, 9-98) mg/g, mean eGFR was 49±18 (standard deviation) mL/min/1.73m2, mean age was 52±9 years, and median graft vintage was 4.1 (Q1-Q3, 1.7-7.4) years. There were 1,017 (29%) with ACR < 10mg/g, 912 (26%) with ACR of 10 to 29mg/g, 1,134 (32%) with ACR of 30 to 299mg/g, and 448 (13%) with ACR ≥ 300mg/g. During approximately 4 years, 282 allograft failure events, 497 CVD events, and 407 deaths occurred. Event rates were higher at both lower eGFRs and higher ACR. ACR of 30 to 299 and ≥300mg/g relative to ACR < 10mg/g were independently associated with graft failure (HRs of 3.40 [95% CI, 2.19-5.30] and 9.96 [95% CI, 6.35-15.62], respectively), CVD events (HRs of 1.25 [95% CI, 0.96-1.61] and 1.55 [95% CI, 1.13-2.11], respectively), and all-cause death (HRs of 1.65 [95% CI, 1.23-2.21] and 2.07 [95% CI, 1.46-2.94], respectively). LIMITATIONS: No data for rejection; single ACR assessment. CONCLUSIONS: In a large population of stable kidney transplant recipients, elevated baseline ACR is independently associated with allograft failure, CVD, and death. Future studies are needed to evaluate whether reducing albuminuria improves these outcomes.

Enzyme activity of waste activated sludge extracts.

Wastewater treatment and generated biological sludge provide an alternative source of enzymes to conventional industrial production methods. Here, we present a protocol for extracting enzymes from activated sludge using ultrasonication and surfactant treatment. Under optimum conditions, ultrasound disruption of activated sludge gave recovery rates of protease and cellulase enzymes equivalent to 63.1% and ∼100%, respectively. The extracting of enzymes from activated sludge represents a potentially significant, high-value, resource recovery option for biological sludge generated by municipal wastewater treatment.

Tranexamic Acid for Lower GI Hemorrhage: A Randomized Placebo-Controlled Clinical Trial.

BACKGROUND: Lower GI hemorrhage is a common source of morbidity and mortality. Tranexamic acid is an antifibrinolytic that has been shown to reduce blood loss in a variety of clinical conditions. Information regarding the use of tranexamic acid in treating lower GI hemorrhage is lacking. OBJECTIVE: The aim of this trial was to determine the clinical efficacy of tranexamic acid when used for lower GI hemorrhage. DESIGN: This was a prospective, double-blind, placebo-controlled, randomized clinical trial. SETTINGS: The study was conducted at a tertiary referral university hospital in Australia. PATIENTS: Consecutive patients aged >18 years with lower GI hemorrhage requiring hospital admission from November 2011 to January 2014 were screened for trial eligibility (N = 265). INTERVENTIONS: A total of 100 patients were recruited after exclusions and were randomly assigned 1:1 to either tranexamic acid or placebo. MAIN OUTCOME MEASURES: The primary outcome was blood loss as determined by reduction in hemoglobin levels. The secondary outcomes were transfusion rates, transfusion volume, intervention rates for bleeding, length of hospital stay, readmission, and complication rates. RESULTS: There was no difference between groups with respect to hemoglobin drop (11 g/L of tranexamic acid vs 13 g/L of placebo; p = 0.9445). There was no difference with respect to transfusion rates (14/49 tranexamic acid vs 16/47 placebo; p = 0.661), mean transfusion volume (1.27 vs 1.93 units; p = 0.355), intervention rates (7/49 vs 13/47; p = 0.134), length of hospital stay (4.67 vs 4.74 d; p = 0.934), readmission, or complication rates. No complications occurred as a direct result of tranexamic acid use. LIMITATIONS: A larger multicenter trial may be required to determine whether there are more subtle advantages with tranexamic acid use in some of the secondary outcomes. CONCLUSIONS: Tranexamic acid does not appear to decrease blood loss or improve clinical outcomes in patients presenting with lower GI hemorrhage in the context of this trial. see Video Abstract at http://links.lww.com/DCR/A453.

Uncontrolled burning of solid waste by households in Mexico is a significant contributor to climate change in the country.

Uncontrolled burning of municipal solid waste (MSW) is an important source of air pollution and is wide spread in many developing countries, but only limited data quantify the extent of domestic open burning of household waste. Here, we present some of the first field data to be reported on the uncontrolled domestic burning of waste. A representative community of Mexico (Huejutla de Reyes Municipality) was investigated and household surveys, interviews with waste operators and a waste characterisation analysis were completed to assess the extent of, and factors controlling, the open burning of waste. Waste collection provision to rural communities was very limited and, consequently 92% of households in rural areas reported that they disposed of waste by uncontrolled burning in backyards or unofficial dumps. Overall, 24% of the total MSW generated in the Municipality was disposed by uncontrolled burning. Urban and periurban areas received twice-weekly collections and the rate of uncontrolled burning was considerably smaller compared to rural households, corresponding to approximately 2% of total waste generation. Carbon equivalency calculations showed that burning waste in backyards represented approximately 6% of the total and 8.5% of fuel related CO2Eq emissions by the municipality. Moreover, the equivalent carbon dioxide (CO2Eq) from black carbon (BC) emitted by uncontrolled burning in backyards was over fifteen times larger compared to methane (CH4) potentially released from equivalent amounts of combustible biodegradable waste disposal at the official dumpsite. An assessment of local respiratory health data showed the incidence of disease was higher in rural than in urban areas, when the opposite trend is typically observed in the international literature; given the high rate of burning activity found in rural areas we suggest that open burning of waste could be a major reason for the apparent poorer respiratory health status of the rural population and requires further investigation. The results emphasise the importance of including BC from uncontrolled burning of waste in international emission inventories of greenhouse gases and in the assessment of the health status of local communities in developing countries where this practice is prevalent.

Cryptosporidium parvum decay during air drying and stockpiling of mesophilic anaerobically digested sewage sludge in a simulation experiment and oocyst counts in sludge collected from operational treatment lagoons in Victoria, Australia.

The inactivation of Cryptosporidium species oocysts during sewage sludge treatment is important to protect human health when the residual biosolids are applied to agricultural land. Quantifying the decay of Cryptosporidium species during sludge treatment for microbiological assurance purposes is difficult if low numbers are present in wastewater. The rate of decay of Cryptosporidium parvum oocysts during solar/air drying treatment and in sludge stockpiles in temperate environment conditions was simulated in laboratory inoculation experiments using sludge sampled from a mesophilic anaerobic digester. Oocyst numbers were also determined in settled lagoon sludge samples collected from three operational rural wastewater treatment plants (WWTPs). C. parvum oocysts were enumerated by immunomagnetic separation followed by staining with vital dyes and examination by confocal laser scanning microscopy. An air-drying/storage period equivalent to 11 weeks was required for a 1 log10 reduction of viable oocysts inoculated into digested sludge. Oocyst viability in air-dried and stored digested sludge decreased with time, but was independent of sludge desiccation and dry solids (DS) content. No oocysts were detected in sludge samples collected from the anaerobic digester, and the average concentration of oocysts found in settled lagoon sludge from the rural WWTP was 4.6 × 102 oocysts/g DS.

Heavy metal nephropathy: considerations for exposure analysis.

Epidemiologic studies have yielded conflicting results regarding the role of heavy metal exposure in recent epidemics of chronic kidney disease (CKD). In this issue of Kidney International, Tsai et al. examined the combined effects of chromium, lead, and cadmium on kidney function using data from the Nutrition and Health Survey in Taiwan. We add this report to our growing understanding of contemporary epidemics of CKD and highlight considerations for exposure analysis in CKD epidemiologic studies.

Serum Phosphorus and Risk of Cardiovascular Disease, All-Cause Mortality, or Graft Failure in Kidney Transplant Recipients: An Ancillary Study of the FAVORIT Trial Cohort.

BACKGROUND: Mild hyperphosphatemia is a putative risk factor for cardiovascular disease [CVD], loss of kidney function, and mortality. Very limited data are available from sizable multicenter kidney transplant recipient (KTR) cohorts assessing the potential relationships between serum phosphorus levels and the development of CVD outcomes, transplant failure, or all-cause mortality. STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: The Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial, a large, multicenter, multiethnic, controlled clinical trial that provided definitive evidence that high-dose vitamin B-based lowering of plasma homocysteine levels did not reduce CVD events, transplant failure, or total mortality in stable KTRs. PREDICTOR: Serum phosphorus levels were determined in 3,138 FAVORIT trial participants at randomization. RESULTS: During a median follow-up of 4.0 years, the cohort had 436 CVD events, 238 transplant failures, and 348 deaths. Proportional hazards modeling revealed that each 1-mg/dL higher serum phosphorus level was not associated with a significant increase in CVD risk (HR, 1.06; 95% CI, 0.92-1.22), but increased transplant failure (HR, 1.36; 95% CI, 1.15-1.62) and total mortality risk associations (HR, 1.21; 95% CI, 1.04-1.40) when adjusted for treatment allocation, traditional CVD risk factors, kidney measures, type of kidney transplant, transplant vintage, and use of calcineurin inhibitors, steroids, or lipid-lowering drugs. These associations were strengthened in models without kidney measures: CVD (HR, 1.14; 95% CI, 1.00-1.31), transplant failure (HR, 1.72; 95% CI, 1.46-2.01), and mortality (HR, 1.34; 95% CI, 1.15-1.54). LIMITATIONS: We lacked data for concentrations of parathyroid hormone, fibroblast growth factor 23, or vitamin D metabolites. CONCLUSIONS: Serum phosphorus level is marginally associated with CVD and more strongly associated with transplant failure and total mortality in long-term KTRs. A randomized controlled clinical trial in KTRs that assesses the potential impact of phosphorus-lowering therapy on these hard outcomes may be warranted.

Three-Dimensional Reconstruction of the Craniofacial Skeleton With Gradient Echo Magnetic Resonance Imaging ("Black Bone"): What Is Currently Possible?

Three-dimensional (3D) reconstructed computed tomography (CT) imaging has become an integral component of craniomaxillofacial patient care. However, with increasing concern regarding the use of ionizing radiation, particularly in children with benign conditions who require repeated examinations, dose reduction and nonionizing alternatives are actively being sought. The "Black Bone" magnetic resonance imaging (MRI) technique provides uniform contrast of the soft tissues to enhance the definition of cortical bone. The aim of this study was to develop methods of 3D rendering of the craniofacial skeleton and to ascertain their accuracy. "Black Bone" MRI datasets acquired from phantoms, adult volunteers and patients were segmented and surface and/or volume rendered using 4 commercially available or open source software packages. Accuracy was explored using a custom phantom (permitting direct measurement), CT and MRI. "Black Bone" MRI datasets were successfully used to create 3D rendered images of the craniofacial skeleton in all 4 software packages. Comparable accuracy was achieved between CT and MRI 3D rendered images of the phantom. The "Black Bone" MRI technique provides a viable 3D alternative to CT examination when imaging the craniofacial skeleton.

Operator models for delivering municipal solid waste management services in developing countries. Part A: The evidence base.

This article presents the evidence base for 'operator models' - that is, how to deliver a sustainable service through the interaction of the 'client', 'revenue collector' and 'operator' functions - for municipal solid waste management in emerging and developing countries. The companion article addresses a selection of locally appropriate operator models. The evidence shows that no 'standard' operator model is effective in all developing countries and circumstances. Each city uses a mix of different operator models; 134 cases showed on average 2.5 models per city, each applying to different elements of municipal solid waste management - that is, street sweeping, primary collection, secondary collection, transfer, recycling, resource recovery and disposal or a combination. Operator models were analysed in detail for 28 case studies; the article summarises evidence across all elements and in more detail for waste collection. Operators fall into three main groups: The public sector, formal private sector, and micro-service providers including micro-, community-based and informal enterprises. Micro-service providers emerge as a common group; they are effective in expanding primary collection service coverage into poor- or peri-urban neighbourhoods and in delivering recycling. Both public and private sector operators can deliver effective services in the appropriate situation; what matters more is a strong client organisation responsible for municipal solid waste management within the municipality, with stable political and financial backing and capacity to manage service delivery. Revenue collection is also integral to operator models: Generally the municipality pays the operator from direct charges and/or indirect taxes, rather than the operator collecting fees directly from the service user.