Depletion of murine intestinal microbiota: effects on gut mucosa and epithelial gene expression

Background Inappropriate cross talk between mammals and their gut microbiota may trigger intestinal inflammation and drive extra-intestinal immune-mediated diseases. Epithelial cells constitute the interface between gut microbiota and host tissue, and may regulate host responses to commensal enteric bacteria. Gnotobiotic animals represent a powerful approach to study bacterial-host interaction but are not readily accessible to the wide scientific community. We aimed at refining a protocol that in a robust manner would deplete the cultivable intestinal microbiota of conventionally raised mice and that would prove to have significant biologic validity. Methodology/Principal Findings Previously published protocols for depleting mice of their intestinal microbiota by administering broad-spectrum antibiotics in drinking water were difficult to reproduce. We show that twice daily delivery of antibiotics by gavage depleted mice of their cultivable fecal microbiota and reduced the fecal bacterial DNA load by 400 fold while ensuring the animals' health. Mice subjected to the protocol for 17 days displayed enlarged ceca, reduced Peyer's patches and small spleens. Antibiotic treatment significantly reduced the expression of antimicrobial factors to a level similar to that of germ-free mice and altered the expression of 517 genes in total in the colonic epithelium. Genes involved in cell cycle were significantly altered concomitant with reduced epithelial proliferative activity in situ assessed by Ki-67 expression, suggesting that commensal microbiota drives cellular proliferation in colonic epithelium. Conclusion We present a robust protocol for depleting conventionally raised mice of their cultivatable intestinal microbiota with antibiotics by gavage and show that the biological effect of this depletion phenocopies physiological characteristics of germ-free mice.

Combined bone and soft-tissue augmentation surgery in temporo-orbital contour reconstruction

Temporal hollowing due to temporal muscle atrophy after standard skull base surgery is common. Various techniques have been previously described to correct the disfiguring defect. Most often reconstruction is performed using freehand molded polymethylmethacrylate cement. This method and material are insufficient in terms of aesthetic results and implant characteristics. We herein propose reconstruction of such defects with a polyetheretherketone (PEEK)-based patient-specific implant (PSI) including soft-tissue augmentation to preserve normal facial topography. We describe a patient who presented with a large temporo-orbital hemangioma that had been repaired with polymethylmethacrylate 25 years earlier. Because of a toxic skin atrophy fistula, followed by infection and meningitis, this initial implant had to be removed. The large, disfiguring temporo-orbital defect was reconstructed with a PEEK-based PSI. The lateral orbital wall and the temporal muscle atrophy were augmented with computer-aided design and surface modeling techniques. The operative procedure to implant and adopt the reconstructed PEEK-based PSI was simple, and an excellent cosmetic outcome was achieved. The postoperative clinical course was uneventful over a 5-year follow-up period. Polyetheretherketone-based combined bony and soft contour remodeling is a feasible and effective method for cranioplasty including combined bone and soft-tissue reconstruction of temporo-orbital defects. Manual reconstruction of this cosmetically delicate area carries an exceptional risk of disfiguring results. Augmentation surgery in this anatomic location needs accurate PSIs to achieve satisfactory cosmetic results. The cosmetic outcome achieved in this case is superior compared with previously reported techniques.

[Adhesions and abdominal pain]

Adhesions occur with a high incidence after intra-abdominal surgery but can also develop due to infections, radiation or for idiopathic reasons. The formation of adhesions is initiated by tissue damage and is the result of peritoneal tissue repair involving the activation of the inflammatory system and the coagulation cascade. Acute small bowel obstruction is one of the most common complications and should be diagnosed rapidly using clinical examination and radiological imaging. A complete obstruction is life threatening and in a high percentage of patients requires rapid surgical intervention by laparotomy or laparoscopy depending on the clinical situation and the patients history. Despite numerous investigations, there is no reliable, commonly used method to prevent intra-abdominal adhesions. Minimizing tissue damage and foreign body exposure, avoiding spillage of intestinal and biliary contents as well as a laparoscopic approach seem to have a beneficial effect on the formation of intra-abdominal adhesions.

Carbon sequestration in Himalaya's alpine meadows: Mitigating cropping encroachment on pastures in Northern Pakistan

Rangelands store about 30% of the world’s carbon and support over 120 million pastoralists globally. Adjusting the management of remote alpine pastures bears a substantial climate change mitigation potential that can provide livelihood support for marginalized pastoralists through carbon payment. Landless pastoralists in Northern Pakistan seek higher income by cropping potatoes and peas over alpine pastures. However, tilling steep slopes without terracing exposes soil to erosion. Moreover, yields decline rapidly requiring increasing fertilizer inputs. Under these conditions, carbon payment could be a feasible option to compensate pastoralists for renouncing hazardous cropping while favoring pastoral activities. The study quantifies and compares C on cropped and grazed land. The hypothesis was that cropping on alpine pastures reduces former carbon storage. The study area located in the Naran valley of the Pakistani Himalayas receives an annual average of 819 mm of rain and 764 mm of snow. Average temperatures remain below 0°C from November to March while frost may occur all year round. A total of 72 soil core samples were collected discriminating land use (cropping, pasture), aspect (North, South), elevation (low 3000, middle 3100, and high 3200 m a.s.l.), and soil depth (shallow 0-10, deep 10-30 cm). Thirty six biomass samples were collected over the same independent variables (except for soil depth) using a 10x10x20 cm steal box inserted in the ground for each sample. Aboveground biomass and coarse roots were separated from the soil aggregate and oven-dried. Soil organic carbon (SOC) and biomass carbon (BC) were estimated through a potassium dichromate oxidation treatment. The samples were collected during the second week of October 2010 at the end of the grazing and cropping season and before the first snowfall. The data was statistically analyzed by means of a one-way analysis of variance. Results show that all variables taken separately have a significant effect on mean SOC [%]: crop/pasture 1.33/1.6, North/South 1.61/1.32, low/middle/high 1.09/1.62/1.68, shallow/deep 1.4/1.53. However, for BC, only land use has a significant effect with more than twice the amount of carbon in pastures [g m-2]: crop/pasture 127/318. These preliminary findings suggest that preventing the conversion of pastures into cropping fields in the Naran valley avoids an average loss of 12.2 t C ha-1 or 44.8 t CO2eq ha-1 representing a foreseeable compensation of 672 € ha-1 for the Naran landless pastoralists who would renounce cropping. The ongoing study shall provide a complete picture for carbon payment integrating key aspects such as the rate of cropping encroachment over pastures per year, the methane leakage from the system due to livestock enteric fermentation, the expected cropping income vs. livestock income and the transaction costs of implementing the mitigation project, certifying it, and verifying carbon credits. A net present value over an infinite time horizon for the mitigation scenario shall be estimated on an iterative simulation to consider weather and price uncertainties. The study will also provide an estimate of the minimum price of carbon at which pastoralists would consider engaging in the mitigation activity.

Vascular Diseases of the Spinal Cord: A Review

OPINION STATEMENT: • In acute spinal cord ischemia syndrome (ASCIS), treatment recommendations are derived from data of cerebral ischemic stroke, atherosclerotic vascular disease and acute spinal cord injury. Besides acute management, secondary prevention is of major importance. Pathologies affecting the aorta as well as underlying cerebrovascular conditions should be treated whenever possible.• ASCIS may occur after aortic surgery, less often after thoracic endovascular aortic repair (TEVAR). Protocols are proposed.• Acute spinal cord hemorrhage can be treated surgically and/or pharmacologically.• Symptomatic treatment in patients with a spinal cord lesion is of major importance. Depending on level and extension of the lesion, there is a risk for systemic and neurological complications, which may be life-threatening.• Each spinal vascular malformation is a unique lesion that needs an individualized treatment algorithm. In case of a symptomatic vascular malformation, endovascular intervention is the primary treatment option.• Spinal dural Arteriovenous fistula (AVF) may be treated endovascularly or surgically. If preoperative localization of the fistula is possible, surgery is feasible with a low complication rate. In comparison, endovascular approaches are less invasive.• Spinal AVM are rather treated endovascularly than surgically or in a stepwise multidisciplinary approach.• Symptomatic and exophytic spinal cavernous angiomas should be treated surgically. Deep spinal cavernous angiomas that are asymptomatic or only show mild symptoms can be observed.

Lack of increase in intracranial pressure after epidural blood patch in spinal cerebrospinal fluid leak

Epidural blood patch (EBP) is one therapeutic measure for patients suffering from spontaneous intracranial hypotension (SIH) or post-lumbar puncture headaches. It has been proposed that an EBP may directly seal a spinal cerebrospinal fluid (CSF) fistula or result in an increase in intracranial pressure (ICP) by a shift of CSF from the spinal to the intracranial compartment. To the best of our knowledge this is the first case of a patient with SIH and neurological deterioration in whom ICP was measured before, during, and after spinal EBP.

Huge ruptured and infected pseudoaneurysm of the ascending aorta and aortic arch with erosion of sternum after previous cardiac surgery

A 77-year-old woman underwent aortic valve replacement and coronary bypass grafting in 2007 in the Emirates. Evolution was uneventful until December 2011. After repeated episodes of unspecific infections, a computed tomographic scan showed a large pseudoaneurysm of the distal ascending aorta. The site of aortic rupture was closed with a Gore-Tex patch and a Staphylococcus aureus infection treated appropriately. Two months later, a small cutaneous lesion on the cranial part of the sternotomy started bleeding. Computed tomographic scan demonstrated recurrence of a false aneurysm with erosion of the sternum and a large subcutaneous hematoma caused by the fistula. The patient was transferred to our institution. The challenges of this case included safe surgical approach (sternotomy, cannulation, perfusion, cerebral protection) as well as complete removal and extensive debridement of the infected material and reconstruction of the aortic arch. Using fully biological material, reconstruction of the ascending aorta and proximal arch was successfully performed.

Treatment of fibrostenotic and fistulizing Crohn's disease

The majority of Crohn's disease patients will develop a complicated disease course over time which is characterized by the occurrence of stricturing and penetrating disease. Penetrating disease comprises internal fistulas (e.g. enteroenteric) and perianal disease. A complicated disease course may be associated with considerable morbidity and professional and personal disabilities. Treatment options for fibrostenotic Crohn's disease comprise endoscopic balloon dilation, stricturoplasties and surgical resection. Treatment of symptomatic perianal fistulizing disease is based on antibiotics, immunomodulators and anti-TNF drugs. Surgical measures include fistula drainage by means of setons, temporary ileostomy or a proctectomy. The presence of internal fistulas often necessitates surgical measures. A close collaboration between the gastroenterologist and the surgeon is mandatory to solve these interdisciplinary challenges.

Quantitative assessment of urea generation and elimination in healthy dogs and in dogs with chronic kidney disease

BACKGROUND: Kinetic assessment of urea, the main end product of protein metabolism, could serve to assess protein catabolism in dogs with chronic kidney disease (CKD). Protein malnutrition and catabolism are poorly documented in CKD and they often are neglected clinically because of a lack of appropriate evaluation tools. HYPOTHESIS: Generation and excretion of urea are altered in dogs with CKD. ANIMALS: Nine dogs with spontaneous CKD (IRIS stages 2-4) and 5 healthy research dogs. METHODS: Endogenous renal clearance (Clrenal) of urea and creatinine was measured first. Exogenous plasma clearance (Clplasma, total body clearance) of the 2 markers then was determined by an IV infusion of urea (250-1,000 mg/kg over 20 minutes) and an IV bolus of creatinine (40 mg/kg). Extrarenal clearance (Clextra) was defined as the difference between Clplasma)and Clrenal. Endogenous urea generation was computed assuming steady-state conditions. RESULTS: Median Clrenal and Clextra of urea were 2.17 and 0.21 mL/min/kg in healthy dogs and 0.37 and 0.28 mL/min/kg in CKD dogs. The proportion of urea cleared by extrarenal route was markedly higher in dogs with glomerular filtration rate<1 mL/kg/min than in normal dogs, reaching up to 85% of the total clearance. A comparable pattern was observed for creatinine excretion, except in 1 dog, Clextra remained<20% of Clplasma. CONCLUSION: Extrarenal pathways of urea excretion are predominant in dogs with advanced CKD and justify exploring adjunctive therapies based on enteric nitrogen excretion in dogs. A trend toward increased urea generation may indicate increased catabolism in advanced CKD.

Cranioplasty after decompressive craniectomy: the effect of timing on postoperative complications

Decompressive craniectomy (DC) due to intractably elevated intracranial pressure mandates later cranioplasty (CP). However, the optimal timing of CP remains controversial. We therefore analyzed our prospectively conducted database concerning the timing of CP and associated post-operative complications. From October 1999 to August 2011, 280 cranioplasty procedures were performed at the authors' institution. Patients were stratified into two groups according to the time from DC to cranioplasty (early, ≤2 months, and late, >2 months). Patient characteristics, timing of CP, and CP-related complications were analyzed. Overall CP was performed early in 19% and late in 81%. The overall complication rate was 16.4%. Complications after CP included epidural or subdural hematoma (6%), wound healing disturbance (5.7%), abscess (1.4%), hygroma (1.1%), cerebrospinal fluid fistula (1.1%), and other (1.1%). Patients who underwent early CP suffered significantly more often from complications compared to patients who underwent late CP (25.9% versus 14.2%; p=0.04). Patients with ventriculoperitoneal (VP) shunt had a significantly higher rate of complications after CP compared to patients without VP shunt (p=0.007). On multivariate analysis, early CP, the presence of a VP shunt, and intracerebral hemorrhage as underlying pathology for DC, were significant predictors of post-operative complications after CP. We provide detailed data on surgical timing and complications for cranioplasty after DC. The present data suggest that patients who undergo late CP might benefit from a lower complication rate. This might influence future surgical decision making regarding optimal timing of cranioplasty.

[Treatment of nonalcoholic steatohepatitis]

NASH associates steatosis with parenchymal inflammation and signs of hepatocellular injuy and even apoptosis. This leads in a minority of patients to fibrosis and in the long term to cirrhosis. NASH regularly occurs in a metabolic context characterized by insulin resistance. Several drugs have been tested in randomized controlled studies. Glitazones improve insulin resistance and also NASH, but are associated with side effects particularly unwelcome in NASH patients. Ursodesoxycholic acid, an hydrophilic biliary acid with hepatoprotective properties, does not improve the histological lesions of NASH. Vitamin E is the only compound which showed so far a positive effect without relevant side effects. However, it is too early to recommend its long-term use in this indication. Finally, the best treatment is not with drugs, but relies on behavioural changes: NASH patients should regularly exercise!

Non-coding keratin variants associate with liver fibrosis progression in patients with hemochromatosis

Background Keratins 8 and 18 (K8/K18) are intermediate filament proteins that protect the liver from various forms of injury. Exonic K8/K18 variants associate with adverse outcome in acute liver failure and with liver fibrosis progression in patients with chronic hepatitis C infection or primary biliary cirrhosis. Given the association of K8/K18 variants with end-stage liver disease and progression in several chronic liver disorders, we studied the importance of keratin variants in patients with hemochromatosis. Methods The entire K8/K18 exonic regions were analyzed in 162 hemochromatosis patients carrying homozygous C282Y HFE (hemochromatosis gene) mutations. 234 liver-healthy subjects were used as controls. Exonic regions were PCR-amplified and analyzed using denaturing high-performance liquid chromatography and DNA sequencing. Previously-generated transgenic mice overexpressing K8 G62C were studied for their susceptibility to iron overload. Susceptibility to iron toxicity of primary hepatocytes that express K8 wild-type and G62C was also assessed. Results We identified amino-acid-altering keratin heterozygous variants in 10 of 162 hemochromatosis patients (6.2%) and non-coding heterozygous variants in 6 additional patients (3.7%). Two novel K8 variants (Q169E/R275W) were found. K8 R341H was the most common amino-acid altering variant (4 patients), and exclusively associated with an intronic KRT8 IVS7+10delC deletion. Intronic, but not amino-acid-altering variants associated with the development of liver fibrosis. In mice, or ex vivo, the K8 G62C variant did not affect iron-accumulation in response to iron-rich diet or the extent of iron-induced hepatocellular injury. Conclusion In patients with hemochromatosis, intronic but not exonic K8/K18 variants associate with liver fibrosis development.

Behavioral Economics and Physician Behavior

This study seeks to answer whether the availability heuristic leads physicians to utilize more medical care than is economically efficient. Do rare, salient events alter physicians' perceptions about the probability of patient harm? Do these events lead physicians to overutilize certain medical procedures? This study uses Pennsylvania inpatient hospital admissions data from 2009 aggregated at the physician level to investigate these questions. The data come from the 2009 Pennsylvania Health Care Cost Containment Council (PHC4). The study is divided into two parts. In Part I, we examine whether bad outcomes during childbirth (defined as maternal mortality, an obstetric fistula or a uterine rupture) lead physicians to utilize more cesarean sections on future patients. In Part II, we examine whether bad outcomes associated with appendicitis (defined as patient death, a perforated or ruptured appendix or sepsis) lead physicians to perform more negative appendectomies (appendectomies performed when the patient did not have appendicitis) on future patients. Overall the study does not find evidence to support the claim that the availability heuristic leads physicians to overutilize medical care on future patients. However, the study does find evidence that variations in health care utilization are strongly correlated with individual physician practice patterns. The results of the study also imply that physicians' financial incentives may be a source of variation in health care utilization.

Intraperitoneal mesh implantation for fascial dehiscence and open abdomen

Postoperative fascial dehiscence and open abdomen are severe postoperative complications and are associated with surgical site infections, fistula, and hernia formation at long-term follow-up. This study was designed to investigate whether intraperitoneal implantation of a composite prosthetic mesh is feasible and safe.

Macrophage activating syndrome is associated with lobular hepatitis and severe bile duct injury with cholestasis

Macrophage activating syndrome (MAS) is a rare hematological disorder associated with uncontrolled systemic T-cell activation. Persistent fever, fatigue and hepatosplenomegaly are frequent clinical manifestations, whereas hyperferritinemia, elevated serum lactate dehydrogenase levels and cytopenia are key criteria for the diagnosis of MAS. The nature of liver pathology in MAS has been partially elucidated but destructive biliary lesions have been rarely described. This report illustrates four cases of MAS developing marked cholestasis, leading to one case of biliary cirrhosis necessitating liver transplantation. Histologically, liver involvement was characterized in all cases by acute lobular hepatitis, marked hepatocyte apoptosis and small bile duct injury similar to the vanishing bile duct syndrome. Immuno-histological studies showed that the inflammatory changes and bile duct lesions were dominated by the presence of activated macrophages and T-cells, in particular CD8+ lymphocytes, and in part NK-cells. These findings suggest that in MAS, various T-cell triggers such as infection, autoimmune disease and malignancy might result in the release of cytokines, which in turn activate macrophages to trigger a systemic acute phase response and local tissue damage. This communication suggests that a macrophage, T- and NK-cell network is operational in the pathogenesis of the cholangiocyte, hepatocyte and sinus endothelial cell damage in MAS.