Assessment of association between lower ureteric excision technique and oncological outcomes for upper urinary tract urothelial carcinoma: retrospective analysis from the Scottish Renal Cancer Consortium.

PURPOSE: Nephroureterectomy(NU) remains the gold-standard surgical option for the management of upper urinary tract urothelial carcinoma(UTUC). Controversy exists regarding the optimal excision technique of the lower ureter. We sought to compare post-UTUC bladder tumour recurrence across the Scottish Renal Cancer Consortium(SRCC). METHODS: Patients who underwent NU for UTUC across the SRCC 2012-2019 were identified. The impact of lower-end surgical technique along with T-stage, N-stage, tumour location and focality, positive surgical margin, pre-NU ureteroscopy, upper-end technique and adjuvant mitomycin C administration were assessed by Kaplan-Meier and Cox-regression. The primary outcome was intra-vesical recurrence-free survival (B-RFS). RESULTS: In 402 patients, the median follow-up was 29 months. The lower ureter was managed by open transvesical excision in 90 individuals, transurethral and laparoscopic dissection in 76, laparoscopic or open extra-vesical excision in 31 and 42 respectively, and transurethral dissection and pluck in 163. 114(28.4%) patients had a bladder recurrence during follow-up. There was no difference in B-RFS between lower-end techniques by Kaplan-Meier (p = 0.94). When all factors were taken into account by adjusted Cox-regression, preceding ureteroscopy (HR 2.65, p = 0.001), lower ureteric tumour location (HR 2.16, p = 0.02), previous bladder cancer (HR 1.75, p = 0.01) and male gender (HR 1.61, p = 0.03) were associated with B-RFS. CONCLUSION: These data suggest in appropriately selected patients, lower ureteric management technique does not affect B-RFS. Along with lower ureteric tumour location, male gender and previous bladder cancer, preceding ureteroscopy was associated with a higher recurrence rate following NU, and the indication for this should be carefully considered.

Comparison of anatomically informed class solution template trajectories with patient-specific trajectories for stereotactic radiosurgery and radiotherapy.

Class solution template trajectories are used clinically for efficiency, safety, and reproducibility. The aim was to develop class solutions for single cranial metastases radiotherapy/radiosurgery based on intracranial target positioning and compare to patient-specific trajectories in the context of 4π optimization. Template trajectories were constructed based on the open-source Montreal Neurological Institute (MNI) average brain. The MNI brain was populated with evenly spaced spherical target volumes (2 cm diameter, N = 243) and organs-at-risk (OARs) were identified. Template trajectories were generated for six anatomical regions (frontal, medial, and posterior, each with laterality dependence) based on previously published 4π optimization methods. Volumetric modulated arc therapy (VMAT) treatment plans generated using anatomically informed template 4π trajectories and patientspecific 4π trajectories were compared against VMAT plans from a standard four-arc template. Four-arc optimization techniques were compared to the standard VMAT template by placing three spherical targets in each of six anatomical regions of a test patient. This yielded 54 plans to compare various plan quality metrics. Increasing plan technique complexity, the total number of OAR maximum dose reductions compared to the standard arc template for the 6 anatomical classes was 4+/-2 (OFIXEDc) and 7+/-2 (OFIXEDi). In 65.6% of all cases, optimized fixed-couch positions outperformed the standard-arc template. Of the three comparisons, the most complex (OFIXEDi) showed the greatest statistical significance compared to the least complex (VMATi) across 12 plan quality metrics of maximum dose to each OAR, V12Gy, total plan Monitor Units, conformity index, and gradient index (p < 0.00417). In approximately 70% of all cases, 4π optimization methods outperformed the standard-arc template in terms of maximum dose reduction to OAR, by exclusively changing the arc geometry. We conclude that a tradeoff exists between complexity of a class solution methodology compared to patient-specific methods for arc selection, in the context of plan quality improvement.

SBRT of ventricular tachycardia using 4pi optimized trajectories.

PURPOSE: To investigate the possible advantages of using 4pi-optimized arc trajectories in stereotactic body radiation therapy of ventricular tachycardia (VT-SBRT) to minimize exposure of healthy tissues. METHODS AND MATERIALS: Thorax computed tomography (CT) data for 15 patients were used for contouring organs at risk (OARs) and defining realistic planning target volumes (PTVs). A conventional trajectory plan, defined as two full coplanar arcs was compared to an optimized-trajectory plan provided by a 4pi algorithm that penalizes geometric overlap of PTV and OARs in the beam's-eye-view. A single fraction of 25 Gy was prescribed to the PTV in both plans and a comparison of dose sparing to OARs was performed based on comparisons of maximum, mean, and median dose. RESULTS: A significant average reduction in maximum dose was observed for esophagus (18%), spinal cord (26%), and trachea (22%) when using 4pi-optimized trajectories. Mean doses were also found to decrease for esophagus (19%), spinal cord (33%), skin (18%), liver (59%), lungs (19%), trachea (43%), aorta (11%), inferior vena cava (25%), superior vena cava (33%), and pulmonary trunk (26%). A median dose reduction was observed for esophagus (40%), spinal cord (48%), skin (36%), liver (72%), lungs (41%), stomach (45%), trachea (53%), aorta (45%), superior vena cava (38%), pulmonary veins (32%), and pulmonary trunk (39%). No significant difference was observed for maximum dose (p = 0.650) and homogeneity index (p = 0.156) for the PTV. Average values of conformity number were 0.86 ± 0.05 and 0.77 ± 0.09 for the conventional and 4pi optimized plans respectively. CONCLUSIONS: 4pi optimized trajectories provided significant reduction to mean and median doses to cardiac structures close to the target but did not decrease maximum dose. Significant improvement in maximum, mean and median doses for noncardiac OARs makes 4pi optimized trajectories a suitable delivery technique for treating VT.

Visual Acuity Outcomes after Phacoemulsification in Eyes with Good Visual Acuity before Cataract Surgery.

OBJECTIVE: to analyse cataract surgery outcomes and related factors in eyes presenting with good visual acuity. SUBJECT AND METHODS: A retrospective longitudinal study of patients undergoing phacoemulsification between 2014 and 2018 in Moorfields Eye Hospital was conducted. Pre- and post-operative visual acuities were analysed. Inclusion criteria were age ≥40 years and pinhole visual acuity ≥6/9 pre-operatively. Exclusion criteria were no post-operative visual acuity data. The visual acuity change variable was also defined according to post-operative visual acuity being above or below the Snellen 6/9 threshold. RESULTS: 2,720 eyes were included. The unaided logMAR visual acuity improved from 0.54 to 0.20 (p < 0.001), the logMAR visual acuity with glasses improved from 0.35 to 0.05 (p < 0.001), and the logMAR pinhole visual acuity improved from 0.17 to 0.13 (p < 0.001); 8.1% of patients had Snellen visual acuity <6/9 post-operatively. Mean follow-up period was 23.6 ± 9.9 days. In multivariate analysis, factors associated with visual acuity <6/9 post-operatively were age (OR = 0.96, 95% confidence interval [CI] [0.95, 0.98], p < 0.001), vitreous loss (OR = 0.21, 95% CI [0.08, 0.56], p = 0.002), and iris trauma (OR = 0.28, 95% CI [0.10, 0.82] p = 0.02). CONCLUSIONS: Visual acuity improved significantly, although at least 8.1% of them did not reach their pinhole preoperative visual acuity. Worse visual acuity outcomes were associated with increasing age, vitreous loss, and iris trauma. The 6/9 vision threshold may not be able to accurately differentiate those who may benefit from cataract surgery and those who may not.

Radical Chain Reduction of CCl4 Initiated by Illumination of SPEEK Solutions.

Efficient reduction of CCl4 took place upon exposure to 350-nm photons of aqueous solutions containing sulfonated poly(ether etherketone) (SPEEK) as a sensitizer and either poly(vinyl alcohol) (PVA) or HCO2H/HCO2- buffer. The photoreaction formed chloride ions whose concentration increased linearly with time in solutions free of O2, whereas slower reductions occurred in the presence of air. Utilization of formate buffer as the H-atom donor yielded photoreactions at least 10 times faster than those in the presence of PVA and generated CHCl3 as another reaction product. The quantum yield of chloride ion formation, ø(Cl-), was found to be a function of both the SPEEK concentration and concentration of formate buffer. Whereas the quantum efficiency increased steadily with decreasing solution acidity, a drastic surge in the reaction rate occurred in neutral solutions. ø(Cl-) first increased rapidly to a maximum value exceeding 1 at pH 7.3 and then decreased thereafter. The dependence of r(Cl-) on (I0)1/2, where I0 is the light intensity, and the occurrence of postirradiation formation of Cl- through the reduction of CCl4 in the dark are further evidence that the photoreaction proceeded by a chain process. Several of the kinetic features were rationalized by means of a mechanism involving the α-hydroxy radicals of SPEEK and •CCl3 as chain carriers.

Photogeneration of H2O2 in Water-Swollen SPEEK/PVA Polymer Films.

Efficient reduction of O2 took place via illumination with 350 nm photons of cross-linked films containing a blend of sulfonated poly(ether etherketone) and poly(vinyl alcohol) in contact with air-saturated aqueous solutions. Swelling of the solid macromolecular matrices in H2O enabled O2 diffusion into the films and also continuous extraction of the photogenerated H2O2, which was the basis for a method that allowed quantification of the product. Peroxide formed with similar efficiencies in films containing sulfonated polyketones prepared from different precursors and the initial photochemical process was found to be the rate-determining step. Generation of H2O2 was most proficient in the range of 4.9 ≤ pH ≤ 8 with a quantum yield of 0.2, which was 10 times higher than the efficiencies determined for solutions of the polymer blend. Increases in temperature as well as [O2] in solution were factors that enhanced the H2O2 generation. H2O2 quantum yields as high as 0.6 were achieved in H2O/CH3CN mixtures with low water concentrations, but peroxide no longer formed when film swelling was suppressed. A mechanism involving reduction of O2 by photogenerated α-hydroxy radicals from the polyketone in competition with second-order radical decay processes explains the kinetic features. Higher yields result from the films because cross-links present in them hinder diffusion of the radicals, limiting their decay and enhancing the oxygen reduction pathway.

Translational research will fail without surgical leadership: SCOTRRCC a successful surgeon-led Nationwide translational research infrastructure in renal cancer.

BACKGROUND: High quality human biosamples with associated high quality clinical data are essential for successful translational research. Despite this, the traditional approach is for the surgeon to act as a technician in the tissue collection act. Biomarker research presents multiple challenges and the field is littered with failures. Tissue quality, poor clinical information, small sample numbers and lack of validation cohorts are just a few reasons for failure. It is clear that the surgeon involved in tissue acquisition must be fully engaged in the process of biosampling for a specific condition, as this will negate many of the issues for translational research failure due to an inadequate bioresource. APPROACH: In this Matter for Debate paper, the Scottish Collaboration On Translational Research into Renal Cell Cancer (SCOTRRCC) is discussed as an example of a urological surgery lead bioresource which has resulted in a National collection of renal cancer tissue and blood (from over 900 patients to date), negating all of the traditional issues with biobanks because of close enagagement and acknowledgement of urologists and uropathologists from seven centres around Scotland. SCOTRRCC has leveraged renal cancer research in Scotland resulting in several high impact publications and providing a springboard for future research in this disease in Scotland and beyond. CONCLUSIONS: The SCOTRRCC model presented here can be transferred to other surgical disciplines for success in translational research.

Dampening prey cycle overrides the impact of climate change on predator population dynamics: a long-term demographic study on tawny owls.

Predicting the dynamics of animal populations with different life histories requires careful understanding of demographic responses to multifaceted aspects of global changes, such as climate and trophic interactions. Continent-scale dampening of vole population cycles, keystone herbivores in many ecosystems, has been recently documented across Europe. However, its impact on guilds of vole-eating predators remains unknown. To quantify this impact, we used a 27-year study of an avian predator (tawny owl) and its main prey (field vole) collected in Kielder Forest (UK) where vole dynamics shifted from a high- to a low-amplitude fluctuation regime in the mid-1990s. We measured the functional responses of four demographic rates to changes in prey dynamics and winter climate, characterized by wintertime North Atlantic Oscillation (wNAO). First-year and adult survival were positively affected by vole density in autumn but relatively insensitive to wNAO. The probability of breeding and number of fledglings were higher in years with high spring vole densities and negative wNAO (i.e. colder and drier winters). These functional responses were incorporated into a stochastic population model. The size of the predator population was projected under scenarios combining prey dynamics and winter climate to test whether climate buffers or alternatively magnifies the impact of changes in prey dynamics. We found the observed dampening vole cycles, characterized by low spring densities, drastically reduced the breeding probability of predators. Our results illustrate that (i) change in trophic interactions can override direct climate change effect; and (ii) the demographic resilience entailed by longevity and the occurrence of a floater stage may be insufficient to buffer hypothesized environmental changes. Ultimately, dampened prey cycles would drive our owl local population towards extinction, with winter climate regimes only altering persistence time. These results suggest that other vole-eating predators are likely to be threatened by dampening vole cycles throughout Europe.

Photogeneration of H2O2 in SPEEK/PVA aqueous polymer solutions.

Photolysis of air-saturated aqueous solutions containing sulphonated poly(ether etherketone) and poly(vinyl alcohol) results in the generation of hydrogen peroxide. Consumption of oxygen and H2O2 formation are initially concurrent processes with a quantum yield of peroxide generation of 0.02 in stirred or unstirred solutions within the range of 7 ≤ pH ≤ 9. The results are rationalized in terms of O2 reduction by photogenerated α-hydroxy radicals of the polymeric ketone in competition with radical-radical processes that consume the macromolecular reducing agents. Generation of H2O2 is controlled by the photochemical transformation that produces the polymer radicals, which is most efficient in neutral and slightly alkaline solutions. Quenching of the excited state of the polyketone by both H3O(+) and OH(-) affect the yields of the reducing macromolecular radicals and of H2O2. Deprotonation of the α-hydroxy polymeric radicals at pH > 9 accelerate their decay and contribute to suppressing the peroxide yields in basic solutions. Maxima in [H2O2] are observed when illuminations are performed with static systems, where O2 reduction is faster than diffusion of oxygen into the solutions. Under such conditions H2O2 can compete with O2 for the reducing radicals resulting in a consumption of the peroxide.

Magnesium cluster film synthesis by helium nanodroplets.

Atomic and molecular clusters are a unique class of substances with properties that differ greatly from those of the bulk or single atoms due to changes in surface to volume ratio and finite size effects. Here, we demonstrate the ability to create cluster matter films using helium droplet mediated cluster assembly and deposition, a recently developed methodology that condenses atoms or molecules within liquid helium droplets and then gently deposits them onto a surface. In this work, we examine magnesium nanocluster films, which exhibit growth behavior comparable to low-energy cluster beam methods, and demonstrate physical properties and morphology dependent on helium droplet size.

Patient-specific collision zones for 4π trajectory optimized radiation therapy.

PURPOSE: The 4π methodology determines optimized noncoplanar subarcs for stereotactic radiation therapy that minimize dose to organs-at-risk. Every combination of treatment angle is examined, but some angles are not appropriate as a collision would occur between the gantry and the couch or the gantry and the patient. Those combinations of couch and gantry angles are referred to as collision zones. A major barrier to applying 4π to stereotactic body radiation therapy (SBRT) is the unknown shape of the collision zones, which are significant as patients take up a large volume within the 4π sphere. This study presents a system that determines patient-specific collision zones, without additional clinical steps, to enable safe and deliverable noncoplanar treatment trajectories for SBRT patients. METHODS: To augment patient's computed tomography (CT) scan, full body scans of patients in treatment position were acquired using an optical scanner. A library of a priori scans (N = 25) was created. Based on the patients' treatment position and their body dimensions, a library scan is selected and registered to the CT scan of the patient. Next, a model of the couch and immobilization equipment is added to the patient model. This results in a patient model that is then aligned with a model of the treatment LINAC in a "virtual treatment room," where both components can be rotated to test for collisions. To test the collision detection algorithm, an end-to-end test was performed using a cranial phantom. The registration algorithm was tested by comparing the registered patient collision zones to those generated by using the patient's matching scan. RESULTS: The collision detection algorithm was found to have a 97.80% accuracy, a 99.99% sensitivity, and a 99.99% negative predictive value (NPV). Analysis of the registration algorithm determined that a 6 cm buffer was required to achieve a 99.65% mean sensitivity, where a sensitivity of unity is considered to be a requirement for safe treatment delivery. With a 6 cm buffer, the mean accuracy was 86.70% and the mean NPV was 99.33%. CONCLUSIONS: Our method of determining patient-specific collision zones can be accomplished with minimal user intervention based on an a priori library of body surface scans, thus enabling the safe application of 4π SBRT.

Natal conditions alter age-specific reproduction but not survival or senescence in a long-lived bird of prey.

1. Natal conditions and senescence are two major factors shaping life-history traits of wild animals. However, such factors have rarely been investigated together, and it remains largely unknown whether they interact to affect age-specific performance. 2. We used 27 years of longitudinal data collected on tawny owls with estimates of prey density (field voles) from Kielder Forest (UK) to investigate how prey density at birth affects ageing patterns in reproduction and survival. 3. Natal conditions experienced by tawny owls, measured in terms of vole density, dramatically varied among cohorts and explained 87% of the deviance in first-year apparent survival (annual estimates ranging from 0·07 to 0·33). 4. We found evidence for senescence in survival for females as well as for males. Model-averaged estimates showed that adult survival probability declined linearly with age for females from age 1. In contrast, male survival probability, lower on average than for female, declined after a plateau at age 1-3. 5. We also found evidence for reproductive senescence (number of offspring). For females, reproductive performance increased until age 9 then declined. Males showed an earlier decline in reproductive performance with an onset of senescence at age 3. 6. Long-lasting effects of natal environmental conditions were sex specific. Female reproductive performance was substantially related to natal conditions (difference of 0·24 fledgling per breeding event between females born in the first or third quartile of vole density), whereas male performance was not. We found no evidence for tawny owls born in years with low prey density having accelerated rates of senescence. 7. Our results, combined with previous findings, suggest the way natal environmental conditions affect senescence varies not only across species but also within species according to gender and the demographic trait considered.

Population genomics of Drosophila suzukii reveal longitudinal population structure and signals of migrations in and out of the continental United States.

Drosophila suzukii, or spotted-wing drosophila, is now an established pest in many parts of the world, causing significant damage to numerous fruit crop industries. Native to East Asia, D. suzukii infestations started in the United States a decade ago, occupying a wide range of climates. To better understand invasion ecology of this pest, knowledge of past migration events, population structure, and genetic diversity is needed. In this study, we sequenced whole genomes of 237 individual flies collected across the continental United States, as well as several sites in Europe, Brazil, and Asia, to identify and analyze hundreds of thousands of genetic markers. We observed strong population structure between Western and Eastern US populations, but no evidence of any population structure between different latitudes within the continental United States, suggesting that there are no broad-scale adaptations occurring in response to differences in winter climates. We detect admixture from Hawaii to the Western United States and from the Eastern United States to Europe, in agreement with previously identified introduction routes inferred from microsatellite analysis. We also detect potential signals of admixture from the Western United States back to Asia, which could have important implications for shipping and quarantine policies for exported agriculture. We anticipate this large genomic dataset will spur future research into the genomic adaptations underlying D. suzukii pest activity and development of novel control methods for this agricultural pest.

Toward the combined optimization of dynamic axes (CODA) for stereotactic radiotherapy and radiosurgery using fixed couch trajectories.

PURPOSE: To develop a novel system for patient-specific combined optimization of couch, collimator, and gantry angles for use in volumetric modulated arc therapy (VMAT) treatment planning. The system was designed to produce highly compact dose distributions by extensively sampling the 4π space. Automated fixed couch trajectory planning was used to reduce normal tissue doses by avoiding beams-eye-view (BEV) overlap with organs-at-risk (OARs) and improve monitor unit (MU) efficiency through collimator angle optimization. METHODS: By merging distinct BEV objective functions used to optimize the couch rotation angle and collimator angle, a three-dimensional (3D) cost space (the CODA cube) was constructed with axes of gantry, couch, and collimator rotation angles. At each voxel in this CODA cube, the cost of implementing this combination of axes positions in fixed couch trajectories was quantified. The CODA cube was sampled and explored using a modified constrained Bellman-Ford algorithm to suggest low-cost fixed candidate arcs on each plane of the space, from which 10-arcs are chosen throughout the 3D space using a k-means clustering algorithm. These fixed couch trajectories were then imported into the Eclipse treatment planning system (v.11) and inverse-optimized according to clinical standards. Eight artificial cranial targets were contoured in a test-patient anatomy, and seven treatment plans were generated from combinations of three and four targets. The CODA cube optimized plans were compared to standard 4-arc VMAT plans for cranial stereotactic radiotherapy/surgery that were optimized for the same sets of targets; maximum dose to each OAR, V12Gy to normal brain, conformity, and total MUs were compared. Both planning methods were inverse-optimized with identical dosimetric objectives. RESULTS: CODA plans resulted in a reduction in maximum dose to OARs of 20.6% (P < 0.01), with maximum brainstem dose decreased by 2.63 Gy (P = 0.031) on average when compared to the standard arc arrangement. The mean reduction in total MU was 8.6% (P = 0.156), the mean increase in the inverse of the van't Riet conformation number was 0.1%, (P = 0.67) and the mean decrease in normal brain tissue receiving 12 Gy or higher was 3.9% (P = 0.16), when compared to the standard VMAT arc configuration (n = 7). CONCLUSIONS: The optimization of couch, collimator, and gantry angles simultaneously using a 3D optimization space achieved improvement on multiple clinical metrics when compared to the standard VMAT arc configuration. A statistically significant sparing to OAR maximum doses was seen. Combining these optimizations may yield superior results to independent optimization.

Extreme elevation of serum growth hormone-binding protein concentrations resulting from a novel heterozygous splice site mutation of the growth hormone receptor gene.

BACKGROUND/AIMS: Circulating growth hormone-binding protein (GHBP), in humans, is the proteolytic product of the growth hormone receptor (GHR). We investigated a prepubertal male subject who was of short stature, but who had a markedly elevated serum level of GHBP. METHODS: Serum and DNA from the patient and his mother were analyzed. RESULTS: Both the patient and mother had serum GHBP concentrations over 100-fold higher than normal, by assays, and Western and ligand blot analysis. Sequencing of the GHR gene revealed a novel heterozygous C>A transversion at position 785-3 in the acceptor splice site of intron 7. CONCLUSION: In silico analysis of the altered sequence suggested that 785-3(C>A) is a splicing mutation, with either retention of intron 7 or the skipping of exon 8. The consequence is a truncated GHR lacking the transmembrane domain (encoded by exon 8) and the cytoplasmic domain. We hypothesize that this GHR variant cannot anchor to the cell membrane, and the continual secretion into the circulation explains the elevated levels of serum GHBP detected in the patient and his mother. Despite this mutation, the presence of the wild-type GHR allele, presumably, permits some normality in GH-induced action.

Systematic review of handoff mnemonics literature.

A systematic review of published English-language articles on handoffs is conducted (1987 to June 4, 2008). Forty-six articles describing 24 handoff mnemonics are identified by trained reviewers. The majority (82.6%) have been published in the last 3 years (2006-2008), and SBAR (Situation, Background, Assessment, Recommendation) is the most frequently cited mnemonic (69.6%). Of 7 handoff research articles, only 4 study mnemonics. All 4 of these studies have relatively small sample sizes (10-100) and lack validated instruments. Only 1 study has obtained IRB approval. Scientifically rigorous research studies are needed to assess the effectiveness of handoff mnemonics. These should be published in the peer-reviewed literature using the Standards for QUality Improvement Reporting Excellence (SQUIRE) guidelines.

Systematic Review of Handoff Mnemonics Literature.

A systematic review of published English-language articles on handoffs is conducted (1987 to June 4, 2008). Forty-six articles describing 24 handoff mnemonics are identified by trained reviewers. The majority (82.6%) have been published in the last 3 years (2006-2008), and SBAR (Situation, Background, Assessment, Recommendation) is the most frequently cited mnemonic (69.6%). Of 7 handoff research articles, only 4 study mnemonics. All 4 of these studies have relatively small sample sizes (10-100) and lack validated instruments. Only 1 study has obtained IRB approval. Scientifically rigorous research studies are needed to assess the effectiveness of handoff mnemonics. These should be published in the peer-reviewed literature using the Standards for QUality Improvement Reporting Excellence (SQUIRE) guidelines.

Growth hormone (GH) insensitivity and insulin-like growth factor-I deficiency in Inuit subjects and an Ecuadorian cohort: functional studies of two codon 180 GH receptor gene mutations.

CONTEXT: Among more than 250 cases of GH insensitivity syndrome (GHIS) reported to date, the largest cohort was identified in southern Ecuador. In the Ecuadorian GHIS cohort, a sense mutation (GAA>GAG) at codon E180 of GH receptor [GHR (E180sp)] results in deletion of codons 181-188. No functional studies of this mutation have been performed, nor have different mutations at codon 180 been reported. OBJECTIVE: We now report identification of a novel GHR mutation, also within codon E180, in two distantly related GHIS subjects of Inuit origin and provide mechanistic insights into the defects caused by the Inuit and Ecuadorian GHR mutations. PATIENTS: The two Inuit subjects, with heights of -5 sd score and -7 sd score, respectively, had elevated circulating levels of GH but low levels of GH-binding protein, IGF-I, and IGF-binding protein-3. RESULTS: Both Inuit subjects carry the same novel nonsense homozygous GHR mutation at codon E180 (GAA->TAA, E180X). In vitro reconstitution experiments demonstrated that GHR (E180sp), but not GHR (E180X), could be stably expressed. GHR (E180sp), however, could not bind GH and could neither activate signal transducer and activator of transcription-5b nor induce -5b-dependent gene expression on GH treatment. Furthermore, the GHR (E180sp), which has a deletion of eight amino acid residues within the GHR dimerization domain, although retaining the ability to homodimerize, was defective in trafficking to the cell surface. CONCLUSIONS: The E180X mutation identified in two Inuit patients resulted in a truncated, unstably expressed GHR variant, whereas the E180 splicing mutation previously identified in the Ecuadorian cohort, affected both GH binding and GHR trafficking and rendered the abnormal GHR nonfunctional.

Role of leptin and melanocortin signaling in uremia-associated cachexia.

The pathogenesis of cachexia in patients with uremia is unknown. We tested the hypothesis that uremia-associated cachexia is caused by leptin signaling through the hypothalamic melanocortin receptor 4 (MC4-R). We performed either subtotal nephrectomy (N) or sham operations in WT, leptin receptor-deficient (db/db), and MC4-R knockout (MC4-RKO) mice. The animals were on 17% protein diets, and none of the uremic animals were acidotic. WT-N mice produced a classic syndrome of cachexia characterized by decreased food intake, increased metabolic rate, and loss of lean body mass. Corrected leptin levels were elevated. db/db mice and MC4-RKO mice resisted the cachexic effects of uremia on weight gain, body composition, and metabolic rate. Likewise, treatment of WT mice with intracranial agouti-related peptide reversed the cachexic effects of uremia on appetite, weight gain, body composition, and metabolic rate. Gene expression of ubiquitin C and proteasome subunits C2, C3, and C9 was not changed in the uremic animals, suggesting that other pathways are involved in this model of nonacidotic uremic cachexia. The results of this study suggest that elevated circulating levels of cytokines such as leptin may be an important cause of uremia-associated cachexia via signaling through the central melanocortin system.

IGFBP-3 sensitizes prostate cancer cells to interferon-gamma-induced apoptosis.

OBJECTIVE: Insulin-like growth factor binding protein-3 (IGFBP-3) has been shown to exhibit diverse biological actions, including IGF-independent effects on cell growth and cell death. Here we report that IGFBP-3 sensitizes prostate cancer cells to interferon-gamma (IFN-gamma)-induced apoptosis and inhibition of cell proliferation. DESIGN: The cell growth or cell death of prostate cells in response to the treatments of IGFBPs and/or IFN-gamma was measured, and the signaling pathways mediating these actions assessed. RESULTS: Cell proliferation was minimally affected when M12 prostate cancer cells were treated with exogenous IGFBP-3 (1-5 microg/ml), IGFBP-1 (1-5 microg/ml) or IFN-gamma (20 U/ml). However, strong inhibition of cell growth and significant apoptosis were observed when M12 cells were co-treated with IGFBP-3 and IFN-gamma, but not with IGFBP-1 and IFN-gamma. These effects were IGF-independent and appear not to require intracellular localization of IGFBP-3, as similar results were obtained with mutants of IGFBP-3 that either could not bind IGF or has impaired ability to be internalized. Further analyses revealed that IGFBP-3, but not IGFBP-1, could significantly enhance the weak tyrosine phosphorylation of STAT1 induced by IFN-gamma (20 U/ml) alone. The IGFBP-3-promoted apoptosis in the presence of IFN-gamma could also be abrogated by blockade of the mTOR pathway with its pharmacological inhibitors, LY294002 or rapamycin. CONCLUSIONS: These results demonstrated that in a cancer cell line not responsive to exogenous IGFBP-3 alone, IGFBP-3 sensitized the cells to the anti-proliferative, proapoptotic actions of IFN-gamma through an IGF-independent, STAT1- and mTOR-dependent mechanism.