Hedgehog signaling is required for the maintenance of mesenchymal nephron progenitors

Background

Mesenchymal nephron progenitors (mNPs) give rise to all nephron tubules in the mammalian kidney. Since premature depletion of these cells leads to low nephron numbers, high blood pressure, and various renal diseases, it is critical to understand how mNPs are maintained. While Fgf, Bmp, and Wnt signaling pathways are known to be required for the maintenance of these cells, it is unclear if any other signaling pathways also play roles.

Methods

To test the potential role of Hedgehog signaling in mNPs, we conditionally deleted Shh from the collecting duct and Smo from the nephron lineage. To identify the genes regulated by Hedgehog signaling in mNPs, we performed RNA-seq analysis from mNPs with different Smo doses. To test if the upregulation of Notch signaling mimics loss of Hedgehog signaling, we performed Jag1 gain-of-function study in mNPs.

Results

We found that loss of either Shh or Smo resulted in premature depletion of mNPs. Our transcriptional profiling data from Smo loss- and gain-of-function mutant mNPs suggested that Hedgehog signaling inhibited the activation of Notch signaling and upregulated the expression of Fox transcription factors such as Foxc1 and Foxp4. Consistent with these observations, we found that ectopic expression of Jag1 caused the premature depletion of mNPs as seen in the Smo mutant kidney. We also found that Foxc1 was capable of binding to mitotic condensed chromatin, a feature of a mitotic bookmarking factor.

Conclusions

Our study demonstrates a previously unappreciated role of Hedgehog signaling in preventing premature depletion of mNPs by repressing Notch signaling and likely by activating the expression of Fox factors.

Single-cell sequencing dissects the transcriptional identity of activated fibroblasts and identifies novel persistent distal tubular injury patterns in kidney fibrosis

Examining kidney fibrosis is crucial for mechanistic understanding and developing targeted strategies against chronic kidney disease (CKD). Persistent fibroblast activation and tubular epithelial cell (TEC) injury are key CKD contributors. However, cellular and transcriptional landscapes of CKD and specific activated kidney fibroblast clusters remain elusive. Here, we analyzed single cell transcriptomic profiles of two clinically relevant kidney fibrosis models which induced robust kidney parenchymal remodeling. We dissected the molecular and cellular landscapes of kidney stroma and newly identified three distinctive fibroblast clusters with "secretory", "contractile" and "vascular" transcriptional enrichments. Also, both injuries generated failed repair TECs (frTECs) characterized by decline of mature epithelial markers and elevation of stromal and injury markers. Notably, frTECs shared transcriptional identity with distal nephron segments of the embryonic kidney. Moreover, we identified that both models exhibited robust and previously unrecognized distal spatial pattern of TEC injury, outlined by persistent elevation of renal TEC injury markers including Krt8 and Vcam1, while the surviving proximal tubules (PTs) showed restored transcriptional signature. We also found that long-term kidney injuries activated a prominent nephrogenic signature, including Sox4 and Hox gene elevation, which prevailed in the distal tubular segments. Our findings might advance understanding of and targeted intervention in fibrotic kidney disease.

Value of prolonged scrotal drainage after penile prosthesis implantation: a multicenter prospective nonrandomized pilot study

We aimed to understand the risks and benefits of post-inflatable penile prosthesis (IPP) implantation drainage and optimal duration. Our patients were divided into 3 groups: Group 1 (n = 114) had no drain placed, Group 2 had a drain placed for 24 h (n = 114) and Group 3 had a drain placed for 72 h (n = 117). Postoperative scrotal hematoma and prosthesis infection rates were compared between the groups. The patients from Group 3 demonstrated a statistically significant lower incidence of hematoma on the 10th postoperative day: (n = 1, 0.9%) compared to Group 2: (n = 11, 9.6%) and Group 1: (n = 8, 7%), (p = 0.013). However, on the 3rd postoperative day, there was a statistically significant lower incidence of hematoma in both Groups 3 and 2: (0.9% and 6.1%, respectively) vs. Group 1: (11.4%), (p = 0.004). Hematoma rates followed the same group order after the first day of surgery: 1.7% (n = 2), 5.3% (n = 6), and 8.8% (n = 10), respectively, (p = 0.05). Five patients (4.4%) in Group 1 and four patients (3.5%) in Group 2 developed an IPP associated infection, opposed to only a single patient (0.85%) in Group 3, (p = 0.210). We concluded that prolonged scrotal drainage for 72 h after virgin IPP implantation significantly reduces hematoma and infection rates.

Normal ranges of global left ventricular myocardial work indices in adults: a meta-analysis

Background

Non-invasive global myocardial work recently emerged as new parameter to characterize left ventricle function with potential advantages over both ejection fraction and global longitudinal strain.

Purpose

We aimed to perform a meta-analysis of normal ranges of non-invasive left ventricular myocardial work (MW) indices including global constructive work (GCW), global work index (GWI), global wasted work (GWW), and global work efficiency (GWE) and to identify confounding factors that may contribute to variance in reported measures.

Methods

The authors searched four databases, Pubmed, Scopus, Embase, and Cochrane Library through January 2021 using the key terms “myocardial work”,“global constructive work”, “global wasted work”, “global work index”, “global work efficiency”. Studies were included if the articles reported LV myocardial work using 2D transthoracic echocardiography in healthy normal subjects, either in the control group or comprising the entire study cohort. The weighted mean was estimated by using the random effect model with a 95% confidence interval. Heterogeneity across studies was assessed using the I2 test. Publication bias was examined by funnel plot and Egger's regression test.

Results

The search yielded 476 articles. After abstract and full text screening we included 13 datasets with 1665 patients for meta-analysis. The reported normal mean values of GCW and GWI among the studies were 2278 (95% CI, 2167 to 23878; I2=95%), and 2.010 (95% CI, 1922 to 2098, I2=97%), respectively. The mean GWE was 96.0 (95% CI, 95.6% to 96.5; I2=92%), and the mean GWW was 79.7% (95% CI, 68.8% to 90.7%; I2=90%) (Figure). Furthermore, age and gender did not significantly contribute to variations in normal values. No evidence of significant publication bias was observed in the funnel plots and the Egger test.

Conclusion

In this meta-analysis, we provide echocardiographic reference ranges for non-invasive indices of MW. These normal values should serve as a template for clinical and research use for this promising technology.

Funding Acknowledgement

Type of funding sources: None.

Monitor unit prediction model for wobbling proton therapy with ridge filters

PURPOSE

We introduced an output factor (cGy/MU) prediction model for wobbling proton beams over the full range of proton energy, scatterer thickness, and the width of spread-out Bragg peak (SOBP).

MATERIALS AND METHODS

From December 2015 to August 2020, 1990 wobbling proton fields were used to treat patients, where 1714 fields had a diameter smaller than 11 cm and 276 had a diameter between 11 and 16 cm, which were designated as small and middle wobbling radius cases, respectively. The output factor is defined as the ratio of proton absorbed dose at mid-depth of SOBP to monitor unit (MU). It depends dominantly on proton energy, scatterer thickness, and the width of SOBP. We established the prediction model using the polynomial fitting function and determined its coefficients for the small and middle wobbling radius cases. We evaluated the accuracy of our prediction model by calculating the difference between predicted and measured output factors.

RESULTS

For the small wobbling radius cases, the mean value of the output factor difference was 0.22% with a standard deviation of 1.3%. For the middle wobbling radius cases, the mean value was 0.20% and with a standard deviation of 0.79%. The large deviation was especially observed for wobbling proton beams having small field size and small width of SOBP.

CONCLUSIONS

We made a prediction model of output factor for wobbling proton beams, thereby determining MU of each beam. This included the dependency of the output factor on the proton energy between 70 and 230 MeV, scatterer thickness, and the width of SOBP. For 93.6% of the small and 95.5% of the middle wobbling radius cases, the deviation between predicted and measured output factor was below 3%. The cases with deviations of predicted and measured output factor above 3% had small field size and small width of SOBP. The accuracy of our prediction model would be improved by adopting the field size effect and measuring more cases of small field size and small SOBP width in the future.

Clinical outcomes from antihypertensive therapies in moderate or severe aortic stenosis: a systematic review and meta-analysis

Background

Hypertension can negatively affect prognosis in moderate or severe aortic stenosis (AS), but antihypertensive therapy (AHT) is often avoided due to possible deleterious effects such as reduced coronary perfusion, left ventricular dysfunction and haemodynamic compromise.

Purpose

We systematically assessed and compared clinical outcomes in adults with moderate or severe AS treated with and without AHT.

Methods

Two independent reviewers performed screening, data extraction and risk of bias assessments from a systematic search of the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and grey literature without language restrictions up to September 9, 2019. Conflicts were resolved by the third reviewer. Outcomes of interest included mortality, left ventricular (LV) mass index, systolic blood pressure, diastolic blood pressure, and LV ejection fraction. Meta-analysis with pooled effect sizes using random-effects model, were estimated in R.

Results

Of 3,024 citations, 30 studies (26,224 patients) were included in the qualitative synthesis and 23 studies in meta-analysis. AHT was associated with favourable clinical outcomes and was well tolerated. AHT was associated with lower risk of all-cause mortality (Risk Ratio (RR)=0.69, 95% CI: 0.53–0.90, p=0.01, Figure). The effect size appears to differ with type of aortic valve replacement (AVR). AHT was associated with lower risk of acute kidney injury post-transcatheter AVR (RR=0.13, 95% CI:0.05–0.35, p=0.007). Favourable outcomes such as improved haemodynamic and echocardiographic parameters were demonstrated in some studies, but when pooled in meta-analysis, the differences did not reach statistical significance. However, heterogeneity was significant across studies.

Conclusion

This is the first systematic review and meta-analysis to demonstrate that AHT is safe and has a clinical benefit in patients with advanced stages of AS with significant improvement in survival or reduction in mortality without haemodynamic compromise. Further studies are required to determine the best AHT for patients with moderate or severe AS.

Forest plot of AHT effect on mortality.

Funding Acknowledgement

Type of funding source: None

Hnf4a Is Required for the Development of Cdh6-Expressing Progenitors into Proximal Tubules in the Mouse Kidney

BACKGROUND

Hepatocyte NF 4α (Hnf4a) is a major regulator of renal proximal tubule (PT) development. In humans, a mutation in HNF4A impairs PT functions and is associated with Fanconi renotubular syndrome (FRTS). In mice, mosaic deletion of Hnf4a in the developing kidney reduces the population of PT cells, leading to FRTS-like symptoms. The molecular mechanisms underlying the role of Hnf4a in PT development remain unclear.

METHODS

The gene deletion tool Osr2Cre removed Hnf4a in developing nephrons in mice, generating a novel model for FRTS. Immunofluorescence analysis characterized the mutant phenotype, and lineage analysis tested whether Cadherin-6 (Cdh6)-expressing cells are PT progenitors. Genome-wide mapping of Hnf4a binding sites and differential gene analysis of Hnf4a mutant kidneys identified direct target genes of Hnf4a.

RESULTS

Deletion of Hnf4a with Osr2Cre led to the complete loss of mature PT cells, lethal to the Hnf4a mutant mice. Cdh6^high, lotus tetragonolobus lectin-low (LTL^low) cells serve as PT progenitors and demonstrate higher proliferation than Cdh6^low, LTL^high differentiated PT cells. Additionally, Hnf4a is required for PT progenitors to differentiate into mature PT cells. Genomic analyses revealed that Hnf4a directly regulates the expression of genes involved in transmembrane transport and metabolism.

CONCLUSIONS

Hnf4a promotes the differentiation of PT progenitors into mature PT cells by regulating the expression of genes associated with reabsorption, the major function of PT cells.

Protein Content of Wheat by Near-Infrared Spectroscopy of Whole Grain: Collaborative Study

A collaborative study was performed to assess accuracy, repeatability, and reproducibility of a nearinfrared (near-IR) method for determining crude protein content (PC) of whole-grain wheat. Four types of commercially available near-IR instruments, representing various combinations of wavelength region, mode of energy capture, method of energy dispersion, and treatment of spectral data, were used. Eight, 9,10, and 11 collaborators were involved, the exact number depending on instrument type. All collaborators received 22 samples of whole-grain hard red winter (HRW) wheat. They were furnished reference PCs (i.e., protein concentrations, w/w) corrected to a 12% moisture basis for instrument standardization. AOAC Method 990.03— combustion analysis—was the reference procedure. Standardization consisted of performing one of the following treatments to the instrument manufacturer's (or federal agency's) PC equation: (1) bias correction, (2) slope and intercept correction, or (3) recalibration with inclusion of standardization sample spectra. Standardized equations were then applied to a test set of 12 unknown HRW wheat sample spectra, with 2 samples blindly duplicated. The PCs of test samples ranged from 9 to 16%. Near-IR predictions were compared with reference measurements. Averaged within instrument type, root mean square of differences were 0.22, 0.24, 0.25, and 0.26% PC, depending on instrument. Corrected for bias within the test set, standard errors became 0.22, 0.18, 0.21, and 0.24% PC, respectively. These values were approximately twice the estimated lower limit for error (representing sample inhomogeneity). Overall repeatability relative standard deviation (RSD,) values were 0.92, 0.36, 0.42, and 0.74%, respectively. Overall reproducibility relative standard deviation (RSDR) values were 1.15, 0.61,1.53, and 1.38%. Such values for within-laboratory and between-laboratory variations of the near- IR methods were equivalent to values reported for the combustion method (990.03) for wheat. An inhouse study that examined all 6 U.S. wheat classes with one of the 4 instrument types produced repeatability and reproducibility values similar to those of the collaborative study, suggesting that the near-IR technique may be applied to red, white, hard, soft, and durum wheats. The near-IR method for determination of PC of whole-grain wheat has been adopted First Action (997.06) by AOAC INTERNATIONAL.

β-catenin regulates the formation of multiple nephron segments in the mouse kidney

The nephron is composed of distinct segments that perform unique physiological functions. Little is known about how multipotent nephron progenitor cells differentiate into different nephron segments. It is well known that β-catenin signaling regulates the maintenance and commitment of mesenchymal nephron progenitors during kidney development. However, it is not fully understood how it regulates nephron segmentation after nephron progenitors undergo mesenchymal-to-epithelial transition. To address this, we performed β-catenin loss-of-function and gain-of-function studies in epithelial nephron progenitors in the mouse kidney. Consistent with a previous report, the formation of the renal corpuscle was defective in the absence of β-catenin. Interestingly, we found that epithelial nephron progenitors lacking β-catenin were able to form presumptive proximal tubules but that they failed to further develop into differentiated proximal tubules, suggesting that β-catenin signaling plays a critical role in proximal tubule development. We also found that epithelial nephron progenitors lacking β-catenin failed to form the distal tubules. Expression of a stable form of β-catenin in epithelial nephron progenitors blocked the proper formation of all nephron segments, suggesting tight regulation of β-catenin signaling during nephron segmentation. This work shows that β-catenin regulates the formation of multiple nephron segments along the proximo-distal axis of the mammalian nephron.

Evaluation of vancomycin target trough attainment with published dosing regimens in the neonatal intensive care unit population

BACKGROUND

Study aims to evaluate whether vancomycin dosing from published dosing algorithms correlate with the attainment of target troughs of 10 to 20 mg/L.

METHODS

NICU patients who received minimum three doses of vancomycin and had a trough level met inclusion criteria. Dosing information was retrospectively evaluated to determine which published dosing regimen was followed. Dosing algorithms used were matched to NeoFax/Harriet Lane, renal-function directed dosing, and weight-directed dosing, in which the latter two can be found in Pediatric and Neonatal Lexi-Drugs. Primary outcome was percentage of troughs within therapeutic (10 to 20 mg/L) and subtherapeutic (less than 10 mg/L) levels.

RESULTS

Of 97 troughs evaluated, NeoFax/Harriet Lane accounted for 86.6%, renal-function directed accounted for 5.1%, and weight-directed dosing accounted for 18.5% of dosing algorithms. NeoFax/Harriet Lane, renal-function directed, and weight-directed dosing attained therapeutic levels between 10 to 20 mg/L at a rate of 60.7%, 60%, and 50% of the time, respectively. With respect to initiation of therapy, a higher dose of 15 mg/kg versus 10 mg/kg attained therapeutic levels (p < 0.001; OR 11.22; 95% CI, 3.96 to 31.81), while a serum creatinine value below 0.5 mg/dL attained subtherapeutic levels (p = 0.028; OR 0.068; 95% CI, 0.006 to 0.74).

CONCLUSIONS

NeoFax, Harriet Lane, and renal-directed dosing from Pediatric and Neonatal Lexi-Drugs achieved target troughs within the 10 to 20 mg/L range more often than weight-directed dosing from Pediatric and Neonatal Lexi-Drugs. Initiating therapy at a higher dose and patient serum creatinine value above 0.5 mg/dL were factors significantly associated with a 10 to 20 mg/L range.

Early clinical outcomes of helical tomotherapy/intensity-modulated proton therapy combination in nasopharynx cancer

This study aimed to evaluate the feasibility of combining helical tomotherapy (HT) and intensity‐modulated proton therapy (IMPT) in treating patients with nasopharynx cancer (NPC). From January 2016 to March 2018, 98 patients received definitive radiation therapy (RT) with concurrent chemotherapy (CCRT). Using simultaneous integrated boost and adaptive re‐plan, 3 different dose levels were prescribed: 68.4 Gy in 30 parts to gross tumor volume (GTV), 60 Gy in 30 parts to high‐risk clinical target volume (CTV), and 36 Gy in 18 parts to low‐risk CTV. In all patients, the initial 18 fractions were delivered by HT, and, after rival plan evaluation on the adaptive re‐plan, the later 12 fractions were delivered either by HT in 63 patients (64.3%, HT only) or IMPT in 35 patients (35.7%, HT/IMPT combination), respectively. Propensity‐score matching was conducted to control differences in patient characteristics. In all patients, grade ≥ 2 mucositis (69.8% vs 45.7%, P = .019) and grade ≥ 2 analgesic usage (54% vs 37.1%, P = .110) were found to be less frequent in HT/IMPT group. In matched patients, grade ≥ 2 mucositis were still less frequent numerically in HT/IMPT group (62.9% vs 45.7%, P = .150). In univariate analysis, stage IV disease and larger GTV volume were associated with increased grade ≥ 2 mucositis. There was no significant factor in multivariate analysis. With the median 14 month follow‐up, locoregional and distant failures occurred in 9 (9.2%) and 12 (12.2%) patients without difference by RT modality. In conclusion, comparable early oncologic outcomes with more favorable acute toxicity profiles were achievable by HT/IMPT combination in treating NPC patients.

Clinical implementation of Dosimetry Check™ for TomoTherapy® delivery quality assurance

Purpose

The delivery quality assurance (DQA) of intensity‐modulated radiotherapy (IMRT) plans is a prerequisite for ensuring patient treatments. This work investigated the clinical usefulness of a new DQA system, Dosimetry Check™(DC), on TomoTherapy^®‐based helical IMRT plans.

Methods

The DQA was performed for 15 different TomoTherapy^®‐based clinical treatment plans. In Tomotherapy^® machines, the couch position was set to a height of 400 mm and the treatment plans were delivered using QA‐Treatment mode. For each treatment plan, the plan data and measured beam fluence were transferred to a DC‐installed computer. Then, DC reconstructed the three‐dimensional (3D) dose distribution to the CT images of the patient. The reconstructed dose distribution was compared with that of the original plan in terms of absolute dose, two‐dimensional (2D) planes and 3D volume. The DQA results were compared with those performed by a conventional method using the cheese phantom with ion chamber and radiochromic film.

Results

For 14 out of the 15 treatment plans, the absolute dose difference between the measurement and calculation was less than 3% and the gamma pass rate with the 3%/3 mm gamma evaluation criteria was greater than 95% for both DQA methods. The P‐value calculated using Wilcoxon signed‐rank test was 0.256, which implies no statistically significance in determining the absolute dose difference between the two methods. For one treatment plan generated using the 5.0 cm field width, the absolute dose difference was greater than 3% and the gamma pass rate was less than 95% with DC, while the DQA result with the cheese phantom method passed our TomoTherapy^® DQA tolerance.

Conclusion

We have clinically implemented DC for the DQA of TomoTherapy^®‐based helical IMRT treatment plans. DC carried out the accurate DQA results as performed with the conventional cheese phantom method. This new DQA system provided more information in verifying the dose delivery to patients, while simplifying the DQA process.

Dummy Run of Quality Assurance Program before Prospective Study of Hippocampus-Sparing Whole-Brain Radiotherapy and Simultaneous Integrated Boost for Multiple Brain Metastases from Non-small Cell Lung Cancer: Korean Radiation Oncology Group (KROG) 17-06 Study

Purpose

Lung Cancer Subcommittee of Korean Radiation Oncology Group (KROG) has recently launched a prospective clinical trial (KROG 17-06) of hippocampus-sparing whole brain radiotherapy (HS-WBRT) with simultaneous integrated boost (SIB) in treating multiple brain metastases from non-small cell lung cancer. In order to improve trial quality, dummy run studies among the participating institutions were designed. This work reported the results of two-step dummy run procedures of the KROG 17-06 study.

Materials and Methods

Two steps tested hippocampus contouring variability and radiation therapy planning compliance. In the first step, the variation of the hippocampus delineation was investigated for two representative cases using the Dice similarity coefficients. In the second step, the participating institutions were requested to generate a HS-WBRT with SIB treatment plan for another representative case. The compliance of the treatment plans to the planning protocol was evaluated.

Results

In the first step, the median Dice similarity coefficients of the hippocampus contours for two other dummy run cases changed from 0.669 (range, 0.073 to 0.712) to 0.690 (range, 0.522 to 0.750) and from 0.291 (range, 0.219 to 0.522) to 0.412 (range, 0.264 to 0.598) after providing the hippocampus contouring feedback. In the second step, with providing additional plan priority and extended dose constraints to the target volumes and normal structures, we observed the improved compliance of the treatment plans to the planning protocol.

Conclusion

The dummy run studies demonstrated the notable inter-institutional variability in delineating the hippocampus and treatment plan generation, which could be decreased through feedback from the trial center.

Hnf4a deletion in the mouse kidney phenocopies Fanconi renotubular syndrome

Different nephron tubule segments perform distinct physiological functions, collectively acting as a blood filtration unit. Dysfunction of the proximal tubule segment can lead to Fanconi renotubular syndrome (FRTS), with major symptoms such as excess excretion of water, glucose, and phosphate in the urine. It has been shown that a mutation in HNF4A is associated with FRTS in humans and that Hnf4a is expressed specifically in proximal tubules in adult rat nephrons. However, little is known about the role of Hnf4a in nephrogenesis. Here, we found that Hnf4a is expressed in both presumptive and differentiated proximal tubules in the developing mouse kidney. We show that Hnf4a is required for the formation of differentiated proximal tubules but is dispensable for the formation of presumptive proximal tubules. Furthermore, we show that loss of Hnf4a decreased the expression of proximal tubule-specific genes. Adult Hnf4a mutant mice presented with FRTS-like symptoms, including polyuria, polydipsia, glycosuria, and phosphaturia. Analysis of the adult Hnf4a mutant kidney also showed proximal tubule dysgenesis and nephrocalcinosis. Our results demonstrate the critical role of Hnf4a in proximal tubule development and provide mechanistic insight into the etiology of FRTS.

Notch is required for the formation of all nephron segments and primes nephron progenitors for differentiation

Notch signaling plays important roles during mammalian nephrogenesis. To investigate whether Notch regulates nephron segmentation, we performed Notch loss-of-function and gain-of-function studies in developing nephrons in mice. Contrary to the previous notion that Notch signaling promotes the formation of proximal tubules and represses the formation of distal tubules in the mammalian nephron, we show that inhibition of Notch blocks the formation of all nephron segments and that constitutive activation of Notch in developing nephrons does not promote or repress the formation of a specific segment. Cells lacking Notch fail to form the S-shaped body and show reduced expression of Lhx1 and Hnf1b Consistent with this, we find that constitutive activation of Notch in mesenchymal nephron progenitors causes ectopic expression of Lhx1 and Hnf1b and that these cells eventually form a heterogeneous population that includes proximal tubules and other types of cells. Our data suggest that Notch signaling is required for the formation of all nephron segments and that it primes nephron progenitors for differentiation rather than directing their cell fates into a specific nephron segment.

A pilot study of planar coil based magnetic stimulation using acute hippocampal slice in mice

Micromagnetic stimulation using small-sized implantable coils has recently been studied. The main advantage of this method is that it can provide sustainable stimulation performance even if a fibrotic encapsulation layer is formed around the implanted coil by inflammation response, because indirectly induced currents are used to induce neural responses. In previous research, we optimized the geometrical and control parameters used in implantable magnetic stimulation. Based on those results, we fabricated the planar coil and studied the LTP effect in the hippocampal slice by two different magnetic stimulation protocols using the quadripulse stimulation (QPS) pattern. We found that direct magnetic stimulation (DMS) induced insignificant LTP effect and priming magnetic stimulation (PMS) occluded LTP effect after tetanic stimulation, when QPS patterned magnetic stimulation with 1 A current pulse was applied to the planar coil.

Use of plasma human herpesvirus-8 viral load measurement: evaluation of practice in three UK HIV treatment centres

A retrospective audit of plasma human herpesvirus-8 (HHV-8) viral load testing was performed in three HIV treatment centres over 24 months. Reasons for testing (360 tests) were: symptoms of systemic inflammatory response syndrome (SIRS) (fever, lymphadenopathy and raised inflammatory markers); monitoring in known HHV-8 pathology other than Kaposi sarcoma (KS); investigation of known/suspected KS, and other/no reason. Of patients with multicentric Castleman disease (MCD), 14/16 (88%) had detectable plasma HHV-8, as did 27/45 (60%) with biopsy proven or clinically confirmed KS, and 6/19 (32%) with lymphoma. Neither of the two patients with MCD and no detectable HHV-8 had SIRS symptoms at the time of the test. There was wide variation between centres in the indications prompting HHV-8 testing, with a more conservative approach resulting in a higher proportion of positive results. Measuring plasma HHV-8 in the absence of SIRS symptoms, established HHV-8 disease monitoring, or confirmed/suspected KS is unlikely to yield detectable HHV-8 thus allowing potential cost savings.

FOXA1, GATA3 and PPARɣ Cooperate to Drive Luminal Subtype in Bladder Cancer: A Molecular Analysis of Established Human Cell Lines

Discrete bladder cancer molecular subtypes exhibit differential clinical aggressiveness and therapeutic response, which may have significant implications for identifying novel treatments for this common malignancy. However, research is hindered by the lack of suitable models to study each subtype. To address this limitation, we classified bladder cancer cell lines into molecular subtypes using publically available data in the Cancer Cell Line Encyclopedia (CCLE), guided by genomic characterization of bladder cancer by The Cancer Genome Atlas (TCGA). This identified a panel of bladder cancer cell lines which exhibit genetic alterations and gene expression patterns consistent with luminal and basal molecular subtypes of human disease. A subset of bladder cancer cell lines exhibit in vivo histomorphologic patterns consistent with luminal and basal subtypes, including papillary architecture and squamous differentiation. Using the molecular subtype assignments, and our own RNA-seq analysis, we found overexpression of GATA3 and FOXA1 cooperate with PPARɣ activation to drive transdifferentiation of a basal bladder cancer cells to a luminial phenotype. In summary, our analysis identified a set of human cell lines suitable for the study of molecular subtypes in bladder cancer, and furthermore indicates a cooperative regulatory network consisting of GATA3, FOXA1, and PPARɣ drive luminal cell fate.

Characterization and evaluation of an integrated quality monitoring system for online quality assurance of external beam radiation therapy

Purpose

The aim of this work was to comprehensively evaluate a new large field ion chamber transmission detector, Integral Quality Monitor (IQM), for online external photon beam verification and quality assurance. The device is designed to be mounted on the linac accessory tray to measure and verify photon energy, field shape, gantry position, and fluence before and during patient treatment.

Methods

Our institution evaluated the newly developed ion chamber's effect on photon beam fluence, response to dose, detection of photon fluence modification, and the accuracy of the integrated barometer, thermometer, and inclinometer. The detection of photon fluence modifications was performed by measuring 6 MV with fields of 10 cm × 10 cm and 1 cm × 1 cm “correct” beam, and then altering the beam modifiers to simulate minor and major delivery deviations. The type and magnitude of the deviations selected for evaluation were based on the specifications for photon output and MLC position reported in AAPM Task Group Report 142. Additionally, the change in ion chamber signal caused by a simulated IMRT delivery error is evaluated.

Results

The device attenuated 6 MV, 10 MV, and 15 MV photon beams by 5.43 ± 0.02%, 4.60 ± 0.02%, and 4.21 ± 0.03%, respectively. Photon beam profiles were altered with the IQM by < 1.5% in the nonpenumbra regions of the beams. The photon beam profile for a 1 cm × 1 cm² fields were unchanged by the presence of the device. The large area ion chamber measurements were reproducible on the same day with a 0.14% standard deviation and stable over 4 weeks with a 0.47% SD. The ion chamber's dose–response was linear (R² = 0.99999). The integrated thermometer agreed to a calibrated thermometer to within 1.0 ± 0.7°C. The integrated barometer agreed to a mercury barometer to within 2.3 ± 0.4 mmHg. The integrated inclinometer gantry angle measurement agreed with the spirit level at 0 and 180 degrees within 0.03 ± 0.01 degrees and 0.27 ± 0.03 at 90 and 270 degrees. For the collimator angle measurement, the IQM inclinometer agreed with a plum‐bob within 0.3 ± 0.2 degrees. The simulated IMRT error increased the ion chamber signal by a factor of 11–238 times the baseline measurement for each segment.

Conclusions

The device signal was dependent on variations in MU delivered, field position, single MLC leaf position, and nominal photon energy for both the 1 cm × 1 cm and 10 cm × 10 cm fields. This detector has demonstrated utility repeated photon beam measurement, including in IMRT and small field applications.