Faculty Bibliography

OBJECTIVES: Screening of living kidney donors may require scintigraphy to split glomerular filtration rate (GFR). To determine the usefulness of computed tomography (CT) to split GFR, we compared scintigraphy-split GFR to CT-split GFR. We evaluated CT-split GFR as a screening test to detect scintigraphy-split GFR lower than 40 mL/min/1.73 m2/kidney. METHODS: This was a monocentric retrospective study on 346 potential living donors who had GFR measurement, renal scintigraphy, and CT. We predicted GFR for each kidney by splitting GFR using the following formula: Volume-split GFR for a given kidney = measured GFR*[volume of this kidney/(volume of this kidney + volume of the opposite kidney)]. The same formula was used for length-split GFR. We compared length- and volume-split GFR to scintigraphy-split GFR at donation and with a 4-year follow-up. RESULTS: A better correlation was observed between length-split GFR and scintigraphy-split GFR (r = 0.92) than between volume-split GFR and scintigraphy-split GFR (r = 0.89). A length-split GFR threshold of 45 mL/min/1.73 m2/kidney had a sensitivity of 100 % and a specificity of 75 % to detect scintigraphy-split GFR less than 40 mL/min/1.73 m2/kidney. Both techniques with their respective thresholds detected living donors with similar eGFR evolution during follow-up. CONCLUSION: Length-split GFR can be used to detect patients requiring scintigraphy. KEY POINTS: * Excellent correlation between kidney length and scintigraphy predicted GFR * Kidney length screening detects all donors with GFR lower than 40 mL/min/1.73 m 2 * Kidney length screening can replace scintigraphy screening.

Developmental eye defects in X-linked Ocular Albinism type I (OA1) are caused by G-Protein Coupled Receptor 143 (GPR143) mutations. Mutations result in dysfunctional melanosome biogenesis and macromelanosome formation in pigment cells, including melanocytes and retinal pigment epithelium. GPR143, primarily expressed in pigment cells, localizes exclusively to endolysosomal and melanosomal membranes unlike most GPCRs, which localize to the plasma membrane. There is some debate regarding GPR143 function and elucidating the role of this receptor may be instrumental for understanding neurogenesis during eye development and for devising therapies for OA1. Many GPCRs require association with other proteins to function. These GPCR-interacting proteins also facilitate fine-tuning of receptor activity and tissue specificity. We therefore investigated potential GPR143 interaction partners, with a focus on the melanogenic enzyme tyrosinase. GPR143 co-immunoprecipitated with tyrosinase, while confocal microscopy demonstrated colocalization of the proteins. Furthermore, tyrosinase localized to the plasma membrane when co-expressed with a GPR143 trafficking mutant. The physical interaction between the proteins was confirmed using Fluorescence Resonance Energy Transfer. This interaction may be required in order for GPR143 to function as a monitor of melanosome maturation. Identifying tyrosinase as a potential GPR143 binding protein opens new avenues for investigating the mechanisms that regulate pigmentation and neurogenesis.

MicroRNA-122 (miR-122) is abundant in the liver and involved in lipid homeostasis, but its relevance to the long-term risk of developing metabolic disorders is unknown. We therefore measured circulating miR-122 in the prospective population-based Bruneck Study (n = 810; survey year 1995). Circulating miR-122 was associated with prevalent insulin resistance, obesity, metabolic syndrome, type 2 diabetes, and an adverse lipid profile. Among 92 plasma proteins and 135 lipid subspecies quantified with mass spectrometry, it correlated inversely with zinc-α-2-glycoprotein and positively with afamin, complement factor H, VLDL-associated apolipoproteins, and lipid subspecies containing monounsaturated and saturated fatty acids. Proteomics analysis of livers from antagomiR-122-treated mice revealed novel regulators of hepatic lipid metabolism that are responsive to miR-122 inhibition. In the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT, n = 155), 12-month atorvastatin reduced circulating miR-122. A similar response to atorvastatin was observed in mice and cultured murine hepatocytes. Over up to 15 years of follow-up in the Bruneck Study, multivariable adjusted risk ratios per one-SD higher log miR-122 were 1.60 (95% CI 1.30-1.96; P < 0.001) for metabolic syndrome and 1.37 (1.03-1.82; P = 0.021) for type 2 diabetes. In conclusion, circulating miR-122 is strongly associated with the risk of developing metabolic syndrome and type 2 diabetes in the general population.

Objective: We sought to assess our experience between a private (TH) and a public hospital (BH), both staffed by faculty and trainees of the same major university medical center. Methods: Our gastric cancer database was used to identify patients undergoing curative intent resection. Descriptive statistics were used to compare demographic data. Kaplan-Meier survival analysis was used to examine recurrence (RFS) and overall survival (OS). Multivariate proportional hazards regression was used to identify factors associated with RFS and OS. Data were risk - and disease stage-stratified. Results: There were 100 patients in the BH group and 242 in the TH group, with a median age 55 and 70.5 years respectively (p<0.001). The majority of BH patients were Asians (60, 60%), and Caucasians (172, 72.3%) in the TH group. The median number of days from diagnosis to surgical intervention at BH was 47.5 vs. 30 days in the TH (p=0.01). BH group had a smaller BMI and more frequently received distal or subtotal gastrectomy. Perioperative morbidity and mortality was equally distributed, as was 30-day readmission rate. Pathologic staging was similarly distributed. By multivariate analysis, hospital of treatment was not associated with RFS (p=0.48) nor OS (p=0.56). Conclusions: Patients receiving care for gastric cancer at major public hospitals have equally good clinical outcomes when compared to patients treated at private hospitals, if cared for by physicians within the same institution dedicated to disease specific entities. Overall survival by treatment hospital

Increasing percentages of children are being born to older fathers. This has resulted in concerns about the potential adverse effects of advanced paternal age. To help clinicians counsel couples, a systemic review was performed to attempt to address questions that these couples may ask: Should routine sperm testing be performed in older males? Should preimplantation genetic diagnosis (PGD) be performed? How do providers counsel patients about risk? Should young males freeze sperm if they plan to delay paternity? Using the terms "advanced paternal age", "semen testing", "preimplantation genetic diagnosis/screening", and "cryopreservation", a comprehensive search was performed in PubMed and the Cochrane Library, and numerous international societal guidelines were reviewed. In total, 42 articles or guidelines were reviewed. There were no limits placed on the timing of the articles. Thirty articles were found to be relevant and beneficial to answering the above questions. Each question was answered separately by the supporting literature. While primary research exists to support the role of semen testing, PGD/preimplantation genetic screening, and sperm banking in males who may be affected by advancing age, comprehensive studies on the possible clinical benefit of these interventions have yet to be performed. As a result, societal guidelines have yet to incorporate distinct best-practice guidelines on advanced paternal age.

How type I and II interferons prevent periodic reemergence of latent pathogens in tissues of diverse cell types remains unknown. Using homogeneous neuron cultures latently infected with herpes simplex virus 1, we show that extrinsic type I or II interferon acts directly on neurons to induce unique gene expression signatures and inhibit the reactivation-specific burst of viral genome-wide transcription called phase I. Surprisingly, interferons suppressed reactivation only during a limited period early in phase I preceding productive virus growth. Sensitivity to type II interferon was selectively lost if viral ICP0, which normally accumulates later in phase I, was expressed before reactivation. Thus, interferons suppress reactivation by preventing initial expression of latent genomes but are ineffective once phase I viral proteins accumulate, limiting interferon action. This demonstrates that inducible reactivation from latency is only transiently sensitive to interferon. Moreover, it illustrates how latent pathogens escape host immune control to periodically replicate by rapidly deploying an interferon-resistant state.

RNA molecules cause the proteins involved in the formation of germ granules to coalesce into liquid droplets.

Germ cell death occurs in many species [1-3] and has been proposed as a mechanism by which the fittest, strongest, or least damaged germ cells are selected for transmission to the next generation. However, little is known about how the choice is made between germ cell survival and death. Here, we focus on the mechanisms that regulate germ cell survival during embryonic development in Drosophila. We find that the decision to die is a germ cell-intrinsic process linked to quantitative differences in germ plasm inheritance, such that higher germ plasm inheritance correlates with higher primordial germ cell (PGC) survival probability. We demonstrate that the maternal factor lipid phosphate phosphatase Wunen-2 (Wun2) regulates PGC survival in a dose-dependent manner. Since wun2 mRNA levels correlate with the levels of other maternal determinants at the single-cell level, we propose that Wun2 is used as a readout of the overall germ plasm quantity, such that only PGCs with the highest germ plasm quantity survive. Furthermore, we demonstrate that Wun2 and p53, another regulator of PGC survival, have opposite yet independent effects on PGC survival. Since p53 regulates cell death upon DNA damage and various cellular stresses, we hypothesize that together they ensure selection of the PGCs with highest germ plasm quantity and least cellular damage.

The four latent transforming growth factor-beta (TGF-beta) binding proteins LTBP1-4 are extracellular matrix-associated proteins playing a critical role in the activation of TGF-beta. The LTBP1 gene forms two major transcript variants (i.e. Ltbp1S and Ltbp1L) that are derived from different promoters. We have previously shown the importance of LTBP1 in vivo by using three different Ltbp1 null mice that were either deleted for exons 1 and 2 (Ltbp1L knockout), exon 5 (Ltbp1DeltaEx5), or exon 8 (Ltbp1DeltaEx8). While the Ltbp1L knockout and the Ltbp1DeltaEx8 are perinatal lethal and die of cardiovascular abnormalities, the Ltbp1DeltaEx5 is viable because it expresses a short form of Ltbp1L that lacks 55 amino acids (Delta55 variant of Ltbp1) formed by splicing out exon 5, while lacking the Ltbp1S variant. Since only the Ltbp1DeltaEx5 mouse is viable, we have used this model to address aspects of puberty, fertility, age-dependent reproduction, and ovary function. We report for the first time a function of LTBP1 in female reproduction. The Ltbp1DeltaEx5 females showed impaired fertility associated with delayed sexual maturity (p = 0.0074) and ovarian cyst formation in females older than 40 weeks (p = 0.0204).

Purpose The European Neuroendocrine Tumor Society (ENETS) and the American Joint Committee on Cancer (AJCC) staging classifications are two widely used systems in managing pancreatic neuroendocrine tumors. However, there is no universally accepted system. Methods An analysis was performed to evaluate the application of the ENETS and AJCC staging classifications using the SEER registry (N = 2,529 patients) and a multicentric series (N = 1,143 patients). A modified system was proposed based on analysis of the two existing classifications. The modified system was then validated. Results The proportion of patients with AJCC stage III disease was extremely low for both the SEER series (2.2%) and the multicentric series (2.1%). For the ENETS staging system, patients with stage I disease had a similar prognosis to patients with stage IIA disease, and patients with stage IIIB disease had a lower hazard ratio for death than did patients with stage IIIA disease. We modified the ENETS staging classification by maintaining the ENETS T, N, and M definitions and adopting the AJCC staging definitions. The proportion of patients with stage III disease using the modified ENETS (mENETS) system was higher than that of the AJCC system in both the SEER series (8.9% v 2.2%) and the multicentric series (11.6% v 2.1%). In addition, the hazard ratio of death for patients with stage III disease was higher than that for patients with stage IIB disease. Moreover, statistical significance and proportional distribution were observed in the mENETS staging classification. Conclusion An mENETS staging classification is more suitable for pancreatic neuroendocrine tumors than either the AJCC or ENETS systems and can be adopted in clinical practice.