Renal pericytes: regulators of medullary blood flow

Regulation of medullary blood flow (MBF) is essential in maintaining normal kidney function. Blood flow to the medulla is supplied by the descending vasa recta (DVR), which arise from the efferent arterioles of juxtamedullary glomeruli. DVR are composed of a continuous endothelium, intercalated with smooth muscle-like cells called pericytes. Pericytes have been shown to alter the diameter of isolated and in situ DVR in response to vasoactive stimuli that are transmitted via a network of autocrine and paracrine signalling pathways. Vasoactive stimuli can be released by neighbouring tubular epithelial, endothelial, red blood cells and neuronal cells in response to changes in NaCl transport and oxygen tension. The experimentally described sensitivity of pericytes to these stimuli strongly suggests their leading role in the phenomenon of MBF autoregulation. Because the debate on autoregulation of MBF fervently continues, we discuss the evidence favouring a physiological role for pericytes in the regulation of MBF and describe their potential role in tubulo-vascular cross-talk in this region of the kidney. Our review also considers current methods used to explore pericyte activity and function in the renal medulla

Intrathecal analgesia and restrictive perioperative fluid management within enhanced recovery pathway: hemodynamic implications.

BACKGROUND: Intrathecal analgesia and avoidance of perioperative fluid overload are key items within enhanced recovery pathways. Potential side effects include hypotension and renal dysfunction. STUDY DESIGN: From January 2010 until May 2010, all patients undergoing colorectal surgery within enhanced recovery pathways were included in this retrospective cohort study and were analyzed by intrathecal analgesia (IT) vs none (noIT). Primary outcomes measures were systolic and diastolic blood pressure, mean arterial pressure, and heart rate for 48 hours after surgery. Renal function was assessed by urine output and creatinine values. RESULTS: One hundred and sixty-three consecutive colorectal patients (127 IT and 36 noIT) were included in the analysis. Both patient groups showed low blood pressure values within the first 4 to 12 hours and a steady increase thereafter before return to baseline values after about 24 hours. Systolic and diastolic blood pressure and mean arterial pressure were significantly lower until 16 hours after surgery in patients having IT compared with the noIT group. Low urine output (<0.5 mL/kg/h) was reported in 11% vs 29% (IT vs noIT; p = 0.010) intraoperatively, 20% vs 11% (p = 0.387), 33% vs 22% (p = 0.304), and 31% vs 21% (p = 0.478) for postanesthesia care unit and postoperative days 1 and 2, respectively. Only 3 of 127 (2.4%) IT and 1 of 36 (2.8%) noIT patients had a transitory creatinine increase >50%; no patients required dialysis. CONCLUSIONS: Postoperative hypotension affects approximately 10% of patients within an enhanced recovery pathway and is slightly more pronounced in patients with IT. Hemodynamic depression persists for <20 hours after surgery; it has no measurable negative impact and therefore cannot justify detrimental postoperative fluid overload

Simple Clinical Screening Underestimates Malnutrition in Surgical Patients with Inflammatory Bowel Disease-An ACS NSQIP Analysis.

The present large scale study aimed to assess the prevalence and consequences of malnutrition, based on clinical assessment (body mass index and preoperative weight loss) and severe hypoalbuminemia (<3.1 g/L), in a representative US cohort undergoing IBD surgery. The American College of Surgeons National Quality improvement program (ACS-NSQIP) Public User Files (PUF) between 2005 and 2018 were assessed. A total of 25,431 patients were identified. Of those, 6560 (25.8%) patients had severe hypoalbuminemia, 380 (1.5%) patients met ESPEN 2 criteria (≥10% weight loss over 6 months PLUS BMI < 20 kg/m <sup>2</sup> in patients <70 years OR BMI < 22 kg/m <sup>2</sup> in patients ≥70 years), and 671 (2.6%) patients met both criteria (severe hypoalbuminemia and ESPEN 2). Patients who presented with malnutrition according to any of the three definitions had higher rates of overall, minor, major, surgical, and medical complications, longer LOS, higher mortality and higher rates of readmission and reoperation. The simple clinical assessment of malnutrition based on BMI and weight loss only, considerably underestimates its true prevalence of up to 50% in surgical IBD patients and calls for dedicated nutritional assessment

Preliminary report: NIF laser bundle review

As requested in the guidance memo {sup 1}, this committe determined whether there are compelling reasons to recommend a change from the NIF CDR baseline laser. The baseline bundle design based on a tradeoff between cost and technical risk, which is replicated four times to create the required 192 beams. The baseline amplifier design uses bottom loading 1{times}4 slab and flashlamp cassettes for amplifier maintenance and large vacuum enclosures (2.5m high {times} 7m wide in cross-section for each of the two spatial filters in each of the four bundles. The laser beams are arranged in two laser bays configured in a u-shape around the target area. The entire bundle review effort was performed in a very short time (six weeks) and with limited resources (15 personnel part-time). This should be compared to the effort that produced the CDR design (12 months, 50 to 100 personnel). This committee considered three alternate bundle configurations (2{times}2, 4{times}2, and 4{times}4 bundles), and evaluated each bundle against the baseline design using the seven requested issues in the guidance memo: Cost; schedule; performance risk; maintainability/operability; hardware failure cost exposure; activation; and design flexibility. The issues were reviewed to identify differences between each alternate bundle configuration and the baseline

Cost drivers of locally advanced rectal cancer treatment-An analysis of a leading healthcare insurer.

To evaluate the economic burden of locally advanced rectal cancer (LARC) treatment from a society perspective through analysis of health insurance-derived data of commercially insured and Medicare Advantage (MA) patients. Retrospective cost analysis of patients undergoing rectal resection within a multimodal (neoadjuvant chemoradiation + adjuvant chemotherapy) treatment strategy between January 1, 2010 and October 31, 2018, using the claims OptumLabs Data Warehouse database. In total, 1738 (935 commercial and 803 MA) patients were included. Overall treatment costs totaled $230,881,746 (on average$183 653 ± 82 384 per commercially insured and $73 681 ± 32 917 per MA patient). Cost distribution according to category (commercially insured patients) was: 29.92% related to outpatient care (follow-up visits/diagnostics), radiotherapy: 21.83%, index resection: 20.62%, chemotherapy: 17.44%, surgical inpatient: 6.32%, medical inpatient: 3.28%, emergency room: 0.58%. Relative cost distribution of the index resection itself differed marginally between the three approaches and was 21.49% for open, 19.30% for laparoscopic, and 20.93% for robotic surgery. Relative cost distributions of neoadjuvant, adjuvant, and outpatient treatments remained unchanged, independently of the surgical approach. This representation was similar in MA patients. Index-surgery related costs were outweighed by costs related to oncological and outpatient workup/follow-up treatments independently of both surgical approach and insurance type

Flux-rope twist in eruptive flares and CMEs : due to zipper and main-phase reconnection

Funding: UK Science and Technology Facilities CouncilThe nature of three-dimensional reconnection when a twisted flux tube erupts during an eruptive flare or coronal mass ejection is considered. The reconnection has two phases: first of all, 3D “zipper reconnection” propagates along the initial coronal arcade, parallel to the polarity inversion line (PIL); then subsequent quasi-2D “main phase reconnection” in the low corona around a flux rope during its eruption produces coronal loops and chromospheric ribbons that propagate away from the PIL in a direction normal to it. One scenario starts with a sheared arcade: the zipper reconnection creates a twisted flux rope of roughly one turn (2π radians of twist), and then main phase reconnection builds up the bulk of the erupting flux rope with a relatively uniform twist of a few turns. A second scenario starts with a pre-existing flux rope under the arcade. Here the zipper phase can create a core with many turns that depend on the ratio of the magnetic fluxes in the newly formed flare ribbons and the new flux rope. Main phase reconnection then adds a layer of roughly uniform twist to the twisted central core. Both phases and scenarios are modeled in a simple way that assumes the initial magnetic flux is fragmented along the PIL. The model uses conservation of magnetic helicity and flux, together with equipartition of magnetic helicity, to deduce the twist of the erupting flux rope in terms the geometry of the initial configuration. Interplanetary observations show some flux ropes have a fairly uniform twist, which could be produced when the zipper phase and any pre-existing flux rope possess small or moderate twist (up to one or two turns). Other interplanetary flux ropes have highly twisted cores (up to five turns), which could be produced when there is a pre-existing flux rope and an active zipper phase that creates substantial extra twist.PostprintPublisher PDFPeer reviewe

Trends of complications and innovative techniques' utilization for colectomies in the United States.

Despite an increasing trend towards utilization of minimally invasive approaches (MIS), results regarding their safety profile are contradictory. All patients who underwent elective colectomy for any underlying disease with an identifiable operative approach available from the targeted colectomy files of the ACS-NSQIP PUFs 2013 to 2018 were included. The trend of utilization and complication rates of the different operative approaches (open, laparoscopic, robotic) were assessed during the inclusion period. Furthermore, overall, surgical, and medical complications were compared between the three approaches. The study cohort included 78,987 patients. Of them, 12,335 (15.6%) patients underwent open, 57,874 (73.3%) laparoscopic, and 8,778 (11.1%) robotic surgery. There was an increasing trend towards the utilization of robotic surgery (2.5% increase per year) at the expense of the other approaches. With the increasing trend toward the utilization of the robotic approach, a decreasing trend in overall and surgical complications and length of stay was observed. After adjusting for the baseline confounders, robotic surgery was associated with shorter length of stay, lower rate of overall (OR 0.397; p < 0.05 compared to open and OR: 0.763; p < 0.05 compared to laparoscopy) and surgical complications (OR: 0.464; p < 0.05 compared to open and OR: 0.734; p < 0.05 compared to laparoscopy). This study revealed an increasing trend toward the utilization of MIS for elective colectomy in the US. Robotic surgery was associated with a decreasing trend in overall and surgical morbidity and length of stay

Oral Antibiotics Bowel Preparation Without Mechanical Preparation For Minimally Invasive Colorectal Surgeries: Current Practice And Future Prospects.

The efficacy of preoperative oral antibiotics alone compared to mechanical bowel preparation and oral antibiotics in minimally invasive surgery is still a matter of ongoing debate. This study aimed to assess the trend of surgical site infection rates in parallel to the utilization of bowel preparation modality over time for minimally invasive surgery colorectal surgeries in the United States. Retrospective analysis. The American College of Surgeons National Surgical Quality Improvement Program database. Adult patients who underwent elective colorectal surgery and reported bowel preparation modality. The trends and compare surgical site infection rates for mutually exclusive groups according to the underlying disease (colorectal cancer, inflammatory bowel disease, and diverticular disease) who underwent bowel preparation using oral antibiotics or combined mechanical bowel preparation and oral antibiotics. Patients who had rectal surgery were analyzed separately. A total of 30,939 patients were included. Of them, 12,417 (40%) had rectal resections. Over the seven-year study period, mechanical bowel preparation and oral antibiotics utilization has increased from 29.3% in 2012 to 64.0% in 2018; p<0.0001 at the expense of no preparation and mechanical bowel preparation alone. Similarly, oral antibiotics utilization has increased from 2.3% in 2012 to 5.5% in 2018; p<0.0001. For colon cancer patients, patients who had oral antibiotics alone had higher superficial surgical site infection rates compared to patients who had combined mechanical bowel preparation and oral antibiotics (1.9% vs. 1.1%; p=0.043). Superficial, deep and organ space surgical site infection rates were similar for all other comparative colon surgery groups (cancer, inflammatory bowel disease, and diverticular disease). Patients with rectal cancer who had oral antibiotics had higher rates of deep surgical site infection (0.9% vs. 0.1%; p=0.004). However, superficial, deep and organ space surgical site infection rates were similar for all other comparative rectal surgery groups. Retrospective nature of the analysis. This study revealed widespread adoption of mechanical bowel preparation and oral antibiotics mechanical bowel preparation and oral antibiotics and increased adoption of oral antibiotics over the study period. Surgical site infection rates appear to be similar from a clinical relevance standpoint among most comparative groups, questioning systematic preoperative addition of mechanical bowel preparation to oral antibiotics alone in all patients for minimally invasive colorectal surgery. See Video Abstract at http://links.lww.com/DCR/B828

National Ignition Facility system design requirements Laser System SDR002

This System Design Requirement document establishes the performance, design, development, and test requirements for the NIP Laser System. The Laser System generates and delivers high-power optical pulses to the target chamber, and is composed of all optical puke creating and transport elements from Puke Generation through Final Optics as well as the special equipment that supports, energizes and controls them. The Laser System consists of the following WBS elements: 1.3 Laser System 1.4 Beam Transport System 1.6 Optical Components 1.7 Laser Control 1.8.7 Final Optics