Analysis of microcystins in alum water treatment sludges: holding times, temperatures, linearity of response, and sensitivity to pre-coagulation cell titers.

ELISA assays are a potential tool to screen for dissolved or cell bound microcystins in drinking water treatment sludges. In order to evaluate this potential more thoroughly, experiments were performed in alum sludges to: (1) evaluate the impacts of sample storage times, temperatures, and sludge composition on spiked microcystin-LR recovery by ELISA; (2) examine the linearity of ELISA responses to spiked microcystin-LR as a function of sludge composition; and (3) examine the sensitivity ELISA and LC/MS/MS to five different concentrations of microcystin-producing cyanobacteria entrained in sludges of two different compositions. During storage experiments, microcystin recovery efficiencies ranged from 85% to 125% across the range of 12 storage time and temperature combinations with recovery efficiencies in 7 of the 12 combinations falling into the 90% to 110% range. During the linearity experiments, linear models fit ELISA responses in all sludge compositions with R2 values ≥ 0.95. During the sensitivity studies, simple freeze/thaw/centrifugation processing combined with ELISA or LC/MS/MS analyses resulted in detection of microcystins in thickened sludges derived from pre-coagulation cell suspensions of 102-106 cells/mL. In addition, the relationships between toxin concentrations in sludges and the original cell titers were linear regardless of analytical method.

Nitrogen-sparging assisted anoxic biological drinking water treatment system.

Existing heterotrophic denitrification reactors rely on microorganisms to consume dissolved oxygen (DO) and create conditions suitable for denitrification, but this practice leads to excessive microbial growth and increased organic carbon doses. An innovative reactor that uses nitrogen gas sparging through a contactor to strip DO was developed and tested in the lab. It reduced influent nitrate from 15 to <1 mg/L as N with nitrite accumulation <1 mg/L as N. It maintained a consistent flow rate and developed minimal headloss, making it easier to operate than the denitrifying dual-media filter that was operated in parallel. Gravel, polyvinyl chloride pieces, and no packing media were assessed as options for the nitrogen-sparged contactor, and gravel was found to support denitrification at the highest loading rate and was resilient to nitrogen-sparging shutoffs and intermittent operation. This innovative reactor appears promising for small drinking water systems.

Effective Early Treatment of Microcystis Exponential Growth and Microcystin Production with Hydrogen Peroxide and Hydroxyapatite.

Mitigating cyanotoxin production is essential to protecting aquatic ecosystems and public health. However, current harmful cyanobacterial bloom (HCB) control strategies have significant shortcomings. Because predicting HCBs is difficult, current HCB control strategies are employed when heavy HCBs have already occurred. Our pilot study developed an effective HCB prediction approach that is employed before exponential cyanobacterial growth and massive cyanotoxin production can occur. We used a quantitative polymerase chain reaction (qPCR) assay targeting the toxin-encoding gene mcyA to signal the timing of treatment. When control measures were applied at an early growth stage or one week before the exponential growth of Microcystis aeruginosa (predicted by qPCR signals), both hydrogen peroxide (H2O2) and the adsorbent hydroxyapatite (HAP) effectively stopped M. aeruginosa growth and microcystin (MC) production. Treatment with either H2O2 (10 mg·L-1) or HAP (40 µm particles at 2.5 g·L-1) significantly reduced both mcyA gene copies and MC levels compared with the control in a dose-dependent manner. While both treatments reduced MC levels similarly, HAP showed a greater ability to reduce mcyA gene abundance. Under laboratory culture conditions, H2O2 and HAP also prevented MC production when applied at the early stages of the bloom when mcyA gene abundance was below 105 copies·mL-1.

Supramesocolic Approach to Roux-en-Y Gastric Bypass when Standard Inframesocolic Approach Is Not Feasible.

BACKGROUND: The traditional approach to a Roux-en-Y gastric bypass is to construct the biliopancreatic and Roux limbs within the inframesocolic space. This requires reflecting the greater omentum, transverse colon, and mesocolon superiorly. This maneuver can be challenging in patients with a robust omentum, hepatomegaly, or significant omental adhesions. The inability to fully reflect the omentum superiorly prevents an appropriate view of the posterior transverse mesocolon and the inframesocolic space from being obtained. This can make it difficult to construct the biliopancreatic and Roux limbs. In order to circumvent the difficult situations described above, a supramesocolic approach to constructing the biliopancreatic and Roux limbs can be performed. This approach avoids the need to reflect the omentum and transverse colon. METHODS: Key steps include entering the lesser sac by transecting the gastrocolic ligament and, next, an aperture in the transverse mesocolon made exposing the ligament of Treitz. The small bowel is then eviscerated into the supramesocolic space. The biliopancreatic and Roux limbs are then created in the usual fashion. All of the small bowel except the Roux limb is then returned through the mesocolon to the inframesocolic space. Peterson's space and the mesocolic defect are then closed using permanent suture. The remainder of the procedure is then performed in the usual fashion. RESULTS: No complications were reported immediately postoperatively or at a 12-month follow-up in all 3 cases. CONCLUSION: The supramesocolic approach to a Roux-en-Y Gastric Bypass is a safe and effective technique when an inframesocolic approach proves difficult.

Surgical Management of a Chronic Sleeve Gastrocolic Fistula with Near Total Gastrectomy and Roux-en-Y Reconstruction.

BACKGROUND: Management of the leak is determined by the duration of the leak from the initial surgery. Acute leaks occurring less than 72 hours after surgery are best managed with reoperation and primary repair. Intermediate leaks, greater than 72 hours but less than 12 weeks, can be managed with non-operative management in non-septic patients. When non-operative management fails beyond 12 weeks the leak is considered a chronic fistula which are best treated with definitive operative management. Sub-total gastrectomy with Roux-En-Y reconstruction with gastrojejunostomy, has been reported with resolution of the fistula in over 90% of cases. OBJECTIVES: To demonstrate the operative management of chronic sleeve gastrectomy leaks. METHODS: A 37-year-old male with a history of a sleeve gastrectomy, developed a chronic fistula between the distal gastric staple line and the transverse colon. After non-operative management failed the patient was taken to the operating room for a diagnostic laparoscopy with plans to perform a revision. A fistula between the distal sleeve staple line and the transverse colon was identified. The gastroesophageal junction was dissected and inspected, there was no fistula at the angle of His. A near total gastrectomy was then performed leaving a small gastric pouch. The colonic side of the fistula was oversewn. Roux-En-Y reconstruction was then performed. RESULTS: No leak identified at four-month follow-up. CONCLUSION: Leak after sleeve gastrectomy can be difficult to manage. Chronic leaks do not respond well to non-operative management. Partial gastrectomy with Roux-En-Y reconstruction is a technically challenging option with good results.

Bariatric surgery outcomes when assisted by fellows and residents: an MBSAQIP analysis of 477,670 patients.

BACKGROUND: Previous reports of bariatric surgery outcomes when cases are assisted by residents and/or fellows have been inconclusive. OBJECTIVE: To compare bariatric surgery outcomes for cases with surgical trainees (ST; residents and fellows) versus nonsurgical trainees (nST; all other assistants) using the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Registry. SETTING: Academic teaching. METHODS: The MBSAQIP Registry was reviewed (2015-2017) for Roux-en-Y gastric bypass, sleeve gastrectomy, and revision surgery based on ST and nST status. Univariate, multivariate logistic regression, and propensity matching analyses were performed. RESULTS: Of 477,670 cases, 26.8% were performed with ST. For ST patients 79.9% were female (versus 80.3% nST) and mean body mass index was 45.2 ± 8 kg/m2 (versus 45.0 ± 8.1 kg/m2 nST). Overall, 31.7% of patients underwent Roux-en-Y gastric bypass (versus 25.7% nST), 65.9% underwent sleeve gastrectomy (versus 71.6% nST), and 2.4% of patients had revision surgery (versus 2.7% nST). After matching, no difference in 30-day mortality was observed between groups. However, ST patients had higher incidence of deep vein thrombosis (P = .004), pulmonary embolism (P = .005), superficial surgical site infection (P < .0001), postoperative sepsis (P = .005), blood transfusions (P = .0307), nonoperative interventions (P = .004), 30-day readmission rates (P < .0001), and longer operative times (P < .0001), but lower 30-day reoperation rates (P = .0001). CONCLUSION: Overall, there was no difference observed in 30-day mortality between the ST and nST groups. However, despite lower 30-day reoperation rates, ST patients exhibited higher rates of postoperative deep vein thrombosis, pulmonary embolism, superficial surgical site infection, postoperative sepsis, blood transfusions, 30-day readmission rates, and longer operative times than nST patients.

Correction to: Impact of age on morbidity and mortality following bariatric surgery.

This article was updated to correct the spelling of Nicholas Dugan's first name: it is correct as displayed here.

Male gender is an independent risk factor for patients undergoing laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass: an MBSAQIP® database analysis.

BACKGROUND: Male patients undergoing bariatric surgery have (historically) been considered higher risk than females. The aim of this study was to examine the disparity between genders undergoing laparoscopic sleeve gastrectomy (SG) and laparoscopic Roux-en-Y gastric bypass (RYGB) procedures and assess gender as an independent risk factor. METHODS: The MBSAQIP® Data Registry Participant User Files for 2015-2017 was reviewed for patients having primary SG and RYGB. Patients were divided into groups based on gender and procedure. Variables for major complications were grouped together, including but not limited to PE, stroke, and MI. Univariate and propensity matching analyses were performed. RESULTS: Of 429,664 cases, 20.58% were male. Univariate analysis demonstrated males were older (46.48 ± 11.96 vs. 43.71 ± 11.89 years, p < 0.0001), had higher BMI (46.58 ± 8.46 vs. 45.05 ± 7.75 kg/m2, p < 0.0001), and had higher incidence of comorbidities. Males had higher rates of major complications (1.72 vs. 1.05%; p < 0.0001) and 30-day mortality (0.18 vs. 0.07%, p < 0.0001). Significance was maintained after subgroup analysis of SG and RYGB. Propensity matched analysis demonstrated male gender was an independent risk factor for RYGB and SG, major complications [2.21 vs. 1.7%, p < 0.0001 (RYGB), 1.12 vs. 0.89%, p < 0.0001 (SG)], and mortality [0.23 vs. 0.12%, p < 0.0001 (RYGB), 0.10 vs. 0.05%; p < 0.0001 (SG)]. CONCLUSION: Males continue to represent a disproportionately small percentage of bariatric surgery patients despite having no difference in obesity rates compared to females. Male gender is an independent risk factor for major post-operative complications and 30-day mortality, even after controlling for comorbidities.

Impact of age on morbidity and mortality following bariatric surgery.

BACKGROUND: Bariatric surgery is the most effective modality to treat obesity and obesity-related comorbidities. This study sought to utilize the MBASQIP® Data Registry to analyze the impact of age at time of surgery on outcomes following sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) procedures. METHODS: The MBSAQIP® Data Registry for patients undergoing SG or RYGB procedures between 2015 and 2016 was reviewed. Patients were divided into 4 age groups [18-44; 45-54; 55-64; > 65 years]. Minimal exclusions for revisional and/or emergency surgery were selected and combination variables created to classify complications as major or minor. A comorbidity index was constructed to include diabetes, gastroesophageal reflux disease (GERD), obstructive sleep apnea (OSA), and prior cardiac surgery. Univariate and multivariate logistic regression analyses were performed to compare age stratifications to the young adult (18-45 years) cohort. RESULTS: Of 301,605 cases, 279,419 cases (71.2% SG) remained after applying exclusion criteria (79.2% female, mean BMI 45.5 ± 8.1 kg/m2, 8.9% insulin-dependent diabetics). Mean age was 44.7 ± 12.0 years (51.3% 18-44 years; 26.9% 45-54 years; 16.3% 55-64 years; 5.5% > 65 years). A univariate analysis demonstrated preoperative differences of lower BMI with increasing age concomitant with increasing frequency of RYGB and a higher comorbidity index (p < 0.0001 vs. 18-45 years). At age > 45 years, major complications and 30-day mortality increased independent of procedure type (p < 0.0001). A multivariate analysis controlling for comorbidity indices demonstrated increasing age (> 45 years) increased risk for major complications and mortality. CONCLUSION: Overall, bariatric surgery (SG or RYGB) remains a low mortality risk procedure for all age groups. However, all age group classifications > 45 years had higher incidence of major complications and mortality compared to patients 18-45 years (despite older individuals having lower preoperative BMI) indicating delaying surgery is detrimental.

Air, Water Vapor, and Aerosol Transport through Textiles with Surface Functional Coatings of Metal Oxides and Metal-Organic Frameworks.

Currently, air permeable chemical/biological (CB) protective garments are based on activated carbon technology, which reduces moisture vapor transport needed for evaporative cooling and has potential to absorb and concentrate toxic materials. Researchers are exploring classes of sorbent materials that can selectively accumulate and decompose target compounds for potential to enhance protective suits and allow for novel filtration devices. Here, the metal-organic frameworks (MOFs) UiO-66-NH2 and HKUST-1 have been identified as such materials. To better understand how MOFs can perform in future CB protective systems, atomic layer deposition (ALD) and solution deposition were used to modify nonwoven polypropylene and flame-resistant fabrics with HKUST-1 and UiO-66-NH2. Air permeation, water vapor transport, filtration efficiency, and chemical reactivity against chemical agent simulants were assessed in relation to ALD thickness and MOF crystal size. MOF deposition on substrates decreased both air and chemical permeation while increasing filtration efficiency and chemical sorption. Moisture vapor transport was not affected by MOF growth on substrates, which is promising when considering thermal properties of protective garments. Future work should continue to explore how MOF deposition onto fiber and textile substrates impacts transport properties and chemical absorbance.

Creation of a Transposed Mature Arteriovenous Fistula Autograft: A Novel Approach to Treating Steal Syndrome.

BACKGROUND: Autogenous arteriovenous fistula (AVF) creation is the gold standard of hemodialysis access. However, autologous upper extremity AVFs continue to present significant clinical challenges including failure to mature and steal syndrome. We describe treating a patient with dialysis-associated steal syndrome (DASS) by ligating and then transposing a well-developed, mature upper arm cephalic vein AVF into the contralateral arm. METHODS: Our patient is a 76-year-old female with end-stage renal disease (ESRD) secondary to glomerulonephritis, who had a left arm brachiocephalic AVF created in 2007. She developed DASS in 2013, presenting with hand pain and ulcerations on her fingertips. A right brachial-cephalic AVF was created with plans of ligating the left AVF once mature. The right arm AVF did not mature so we created an arteriovenous graft (AVG) in the right arm utilizing the mature left arm cephalic vein as an autograft. RESULTS: The autograft was transposed and implanted in the right upper arm. The translocated AVF worked for 4 years and was eventually ligated due to right hand ischemia secondary to progression of small vessel peripheral arterial disease. CONCLUSIONS: Transposition of autogenous vein grafts using a mature AVF is a viable option for dialysis access in ESRD patients. We report successful utilization of this novel access option in the treatment of a patient with DASS. The mature autograft retains the natural matrix and endothelial lining and thus may potentially prove to offer improved patency and reduced infection rate compared to other available AVG options.

Chemical Protective Textiles of UiO-66-Integrated PVDF Composite Fibers with Rapid Heterogeneous Decontamination of Toxic Organophosphates.

Metal-organic frameworks (MOFs) are a new and growing area of materials with high porosity and customizability. UiO-66, a zirconium-based MOF, has shown much interest to the military because of the ability of the MOF to catalytically decontaminate chemical warfare agents (CWAs). Unfortunately, the applications for MOFs are limited because of their powder form, which is difficult to incorporate into protective clothing. As a result, a new area of research has developed to functionalize fabrics with MOFs to make a wearable multifunctional fabric that retains the desired properties of the MOF. In this work, UiO-66 was incorporated into poly(vinylidene) fluoride/Ti(OH)4 composite fabric using electrospinning and evaluated for its use in chemical protective clothing. The base triethanolamine (TEA) was added to the composite fabric to create a self-buffering system that would allow for catalytic decontamination of CWAs without the need for a buffer solution. The fabrics were tested against the simulants methyl-paraoxon (dimethyl (4-nitrophenyl) phosphate, DMNP), diisopropyl fluorophosphate (DFP), and the nerve agent soman (GD). The results show that all of the samples have high moisture vapor transport and filtration efficiency, which are desirable for protective clothing. The incorporation of TEA decreased air permeation of the fabric, but increased the catalytic activity of the composite fabric against DMNP and DFP. Samples with and without TEA have rapid half-lives ( t1/2) as short as 35 min against GD agent. These new catalytically active self-buffering multifunctional fabrics have great potential for application in chemical protective clothings.

The Impacts of Potassium Permanganate and Powdered Activated Carbon on Cyanotoxin Release.

Bench-scale trials were performed to: (1) Expose Microcystis aeruginosa cells to potassium permanganate doses of 1, 3 and 5 mg/L, at contact times of 15, 30 and 90 minutes, pH levels of 7 and 9, and turbidities of 0.1, 5 and 20 NTU; (2) Compare the impacts of oxidation alone and oxidation plus powdered activated carbon for the final 60 minutes of contact time and (3) evaluate the impact of these treatment conditions on extracellular microcystins, extra- plus intracellular (combined) microcystins, cell membrane integrity and chlorophyll-a concentrations. Toxin releases from the cells were observed at both pH levels. The greatest toxin releases were observed at the lowest KMnO4 doses. The toxin releases were accompanied by relatively stable total cell counts, increases in membrane compromised cells and decreases in chlorophyll-a. The application of 10 mg/L PAC resulted in extracellular toxin concentrations that were markedly lower than those observed in oxidant-only situations.

Removal of estrogens and estrogenicity through drinking water treatment.

Estrogenic compounds have been shown to be present in surface waters, leading to concerns over their possible presence in finished drinking waters. In this work, two in vitro human cell line bioassays for estrogenicity were used to evaluate the removal of estrogens through conventional drinking water treatment using a natural water. Bench-scale studies utilizing chlorine, alum coagulation, ferric chloride coagulation, and powdered activated carbon (PAC) were conducted using Ohio River water spiked with three estrogens, 17ß-estradiol, 17α-ethynylestradiol, and estriol. Treatment of the estrogens with chlorine, either alone or with coagulant, resulted in approximately 98% reductions in the concentrations of the parent estrogens, accompanied by formation of by-products. The MVLN reporter gene and MCF-7 cell proliferation assays were used to characterize the estrogenic activity of the water before and after treatment. The observed estrogenic activities of the chlorinated samples showed that estrogenicity of the water was reduced commensurate with removal of the parent estrogen. Therefore, the estrogen chlorination by-products did not contribute appreciably to the estrogenic activity of the water. Coagulation alone did not result in significant removals of the estrogens. However, addition of PAC, at a typical drinking water plant dose, resulted in removals ranging from approximately 20 to 80%.

The impact of temperature on the performance of anaerobic biological treatment of perchlorate in drinking water.

A 20-month pilot-scale study was conducted to examine the impact of temperature on the performance of an anaerobic biological contractor used to treat perchlorate-contaminated water. The contractor was successfully acclimated with indigenous microorganisms. Influent temperatures varied from 1.4 to 30 degrees C. The objectives of the study were to investigate the effects of temperature on perchlorate removal, nitrate removal, nitrite formation, dissolved oxygen consumption, sulfide production, and nutrient acetate consumption. The results confirmed that consistent biological perchlorate removal to 2 microg /L is feasible at temperatures above 10 degrees C. Effluent concentrations of perchlorate, nitrate, and dissolved oxygen varied inversely with temperature, while sulfide varied positively with temperature. Under the conditions that prevailed during this study, 10 degrees C was a threshold temperature below which microbial activity, including perchlorate reduction, decreased dramatically.

Identification of microcystin toxins from a strain of Microcystis aeruginosa by liquid chromatography introduction into a hybrid linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer.

The cyclic heptapeptide microcystin toxins produced by a strain of Microcystis aeruginosa that has not been investigated previously were separated by liquid chromatography and identified by high-accuracy m/z measurements of their [M + H]+ ions and the fragment ions produced by collision-activated dissociation of the [M + H]+ ions. The cyanobacteria B2666 strain was cultured in a standard growth medium, and the toxins were released from the cells, extracted from the aqueous phase, and concentrated using standard procedures. The microcystins were separated by reversed-phase microbore liquid chromatography and introduced directly into a hybrid linear ion trap-Fourier transform ion cyclotron resonance mass spectrometer with electrospray ionization. The known microcystins (MC) MC-LR, MC-LA, [MeSer7]MC-LR, MC-LL, MC-LF, and MC-L(Aba) were identified along with the two previously unreported structural variants [Asp3]MC-LA and [Asp3]MC-LL. In addition to the [M + H]+ ions, accurate m/z measurements were made of 12-18 product ions for each identified microcystin. The mean difference between measured and calculated exact m/z was less than 2 parts per million, which often allowed assignment of unique compositions to the observed ions. A mechanism is presented that accounts for an important collision-activated dissociation process that gives valuable sequence ions from microcystins that do not contain arginine. The analytical technique used in this work is capable of supporting fairly rapid and very reliable identifications of known microcystins when standards are not available and of most structural variants independent of additional information from other analytical techniques.

Using Dirichlet tessellation to help estimate microbial biomass concentrations.

Dirichlet tessellation was applied to estimate microbial concentrations from microscope well slides. The use of microscopy/Dirichlet tessellation to quantify biomass was illustrated with two species of morphologically distinct cyanobacteria (Microcystis aeruginosa and Anabaena flos aquae), and validated empirically by comparison with chlorophyll a and Coulter count analyses. Biomass estimates obtained by microscopy/Dirichlet tessellation were significantly correlated with the results obtained from chlorophyll a and Coulter analyses.