American Society of Nephrology Kidney TREKS Program.

In response to decreasing numbers of individuals entering into nephrology fellowships, the American Society of Nephrology launched Kidney TREKS (Tutored Research and Education for Kidney Scholars) to stimulate interest in nephrology among medical students, graduate students, and postdoctoral fellows. The program combines a one-week intensive exposure to kidney physiology with a longitudinal mentorship program at the participants' home institutions. Ten years in, an analysis was conducted to assess its effectiveness. We surveyed participants to assess their opinions regarding nephrology before and after the course and followed them longitudinally to determine their career choices. TREKS applicants who were not selected to participate were used as a comparison group. 381 people participated in the program and 242 completed the survey. After TREKS, both medical students and graduate students showed increased interest in nephrology, with rank scores of 5.6±0.2 pre- to 7.5±0.1 post-course for medical students (mean ± standard deviation, n=189, p=0.001) and 7.3±0.3 to 8.7±0.3 (n=53, p=0.001) for graduate students. In long term follow-up, TREKS medical students chose a nephrology pipeline residency at a higher rate than medical students overall (57% vs. 31%, p=0.01) and TREKS applicants who did not participate (47% vs. 31%, p=0.04). Nephrology fellowship rates for these groups exceeded the general population but did not significantly differ between TREKS participants and applicants. PhD students and postdoctoral TREKS participants had a higher rate of participating in nephrology research compared to TREKS applicants (66% vs. 30%, p=0.01). In summary, the ASN Kidney TREKS program has demonstrated that it can improve interest in nephrology in the short term and increase the number of individuals going into nephrology careers. This long-term effect is most evident in PhD students and postdoctoral participants. Further study is needed to assess the impact of TREKS on enrollment in nephrology fellowship programs.

A spatially-resolved transcriptional atlas of the murine dorsal pons at single-cell resolution.

The "dorsal pons", or "dorsal pontine tegmentum" (dPnTg), is part of the brainstem. It is a complex, densely packed region whose nuclei are involved in regulating many vital functions. Notable among them are the parabrachial nucleus, the Kölliker Fuse, the Barrington nucleus, the locus coeruleus, and the dorsal, laterodorsal, and ventral tegmental nuclei. In this study, we applied single-nucleus RNA-seq (snRNA-seq) to resolve neuronal subtypes based on their unique transcriptional profiles and then used multiplexed error robust fluorescence in situ hybridization (MERFISH) to map them spatially. We sampled ~1 million cells across the dPnTg and defined the spatial distribution of over 120 neuronal subtypes. Our analysis identified an unpredicted high transcriptional diversity in this region and pinpointed the unique marker genes of many neuronal subtypes. We also demonstrated that many neuronal subtypes are transcriptionally similar between humans and mice, enhancing this study's translational value. Finally, we developed a freely accessible, GPU and CPU-powered dashboard ( http://harvard.heavy.ai:6273/ ) that combines interactive visual analytics and hardware-accelerated SQL into a data science framework to allow the scientific community to query and gain insights into the data.

Role of ecto-5'-nucleotidase in bladder function.

Purinergic signaling plays an important role in regulating bladder contractility and voiding. Abnormal purinergic signaling is associated with lower urinary tract symptoms (LUTS). Ecto-5'-nucleotidase (NT5E) catalyzes dephosphorylation of extracellular AMP to adenosine, which in turn promotes adenosine-A2b receptor signaling to relax bladder smooth muscle (BSM). The functional importance of this mechanism was investigated using Nt5e knockout (Nt5eKO) mice. Increased voiding frequency of small voids revealed by voiding spot assay was corroborated by urodynamic studies showing shortened voiding intervals and decreased bladder compliance. Myography indicated reduced contractility of Nt5eKO BSM. These data support a role for NT5E in regulating bladder function through modulation of BSM contraction and relaxation. However, the abnormal bladder phenotype of Nt5eKO mice is much milder than we previously reported in A2b receptor knockout (A2bKO) mice, suggesting compensatory response(s) in Nt5eKO mouse bladder. To better understand this compensatory mechanism, we analyzed changes in purinergic and other receptors controlling BSM contraction and relaxation in the Nt5eKO bladder. We found that the relative abundance of muscarinic CHRM3 (cholinergic receptor muscarinic 3), purinergic P2X1, and A2b receptors was unchanged, whereas P2Y12 receptor was significantly downregulated, suggesting a negative feedback response to elevated ADP signaling. Further studies of additional ecto-nucleotidases indicated significant upregulation of the nonspecific urothelial alkaline phosphatase ALPL, which might mitigate the degree of voiding dysfunction by compensating for Nt5e deletion. These data suggest a mechanistic complexity of the purinergic signaling network in bladder and imply a paracrine mechanism in which urothelium-released ATP and its rapidly produced metabolites coordinately regulate BSM contraction and relaxation.

A spatially-resolved transcriptional atlas of the murine dorsal pons at single-cell resolution.

The "dorsal pons", or "dorsal pontine tegmentum" (dPnTg), is part of the brainstem. It is a complex, densely packed region whose nuclei are involved in regulating many vital functions. Notable among them are the parabrachial nucleus, the Kölliker Fuse, the Barrington nucleus, the locus coeruleus, and the dorsal, laterodorsal, and ventral tegmental nuclei. In this study, we applied single-nucleus RNA-seq (snRNA-seq) to resolve neuronal subtypes based on their unique transcriptional profiles and then used multiplexed error robust fluorescence in situ hybridization (MERFISH) to map them spatially. We sampled ~1 million cells across the dPnTg and defined the spatial distribution of over 120 neuronal subtypes. Our analysis identified an unpredicted high transcriptional diversity in this region and pinpointed many neuronal subtypes' unique marker genes. We also demonstrated that many neuronal subtypes are transcriptionally similar between humans and mice, enhancing this study's translational value. Finally, we developed a freely accessible, GPU and CPU-powered dashboard (http://harvard.heavy.ai:6273/) that combines interactive visual analytics and hardware-accelerated SQL into a data science framework to allow the scientific community to query and gain insights into the data.

Smooth Muscle Insulin Receptor Deletion Causes Voiding Dysfunction: A Mechanism for Diabetic Bladder Dysfunction.

Diabetic bladder dysfunction (DBD) is the most common complication in diabetes. Myogenic abnormalities are common in DBD; however, the underlying mechanisms leading to these remain unclear. To understand the importance of smooth muscle insulin receptor (IR)-mediated signaling in the pathogenesis of DBD, we conditionally deleted it to achieve either heterozygous (SMIR+/-) or homozygous (SMIR-/-) deletion in smooth muscle cells. Despite impaired glucose and insulin tolerance seen with SMIR-/- mice, both SMIR+/- and SMIR-/- mice exhibited normal blood glucose and plasma insulin levels. Interestingly, these mice had abnormal voiding phenotypes, that included urinary frequency and small voids, and bladder smooth muscle (BSM) had significantly diminished contraction force. Morphology revealed a dilated bladder with thinner BSM layer, and BSM bundles were disorganized with penetrating interstitial tissue. Deletion of IR elevated FoxO and decreased mTOR protein expression, which further decreased the expression of Chrm3, P2x1, Sm22, and Cav1.2, crucial functional proteins for BSM contraction. Furthermore, we determined the expression of adiponectin in BSM, and deletion of IR in BSM inhibited adiponectin-mediated signaling. In summary, disruption of IR-mediated signaling in BSM caused abnormalities in proliferation and differentiation, leading to diminished BSM contractility and a voiding dysfunction phenotype that recapitulates human DBD.

Aquaporin (AQP) channels in the spiny dogfish, Squalus acanthias I: Characterization of AQP3 and AQP15 function and expression, and localization of the proteins in gill and spiral valve intestine.

Complementary DNAs (cDNAs) for two aquaporin water channel genes (AQP3 and AQP15) were amplified cloned and sequenced to initiate this study. Northern blot analysis was carried out to confirm the mRNA sizes of these AQP genes with AQP3 mRNA bands exhibiting sizes of 1.2 and 1.6 k bases and AQP15 had a mRNA band of 2.1 k bases. Northern blot analysis was also performed on kidney and esophagus total RNA samples from fish acclimated to 75%, 100% or 120% seawater (SW). The level of AQP15 mRNA expression was shown to significantly decrease following salinity acclimation from 100 to 120% SW. An opposite but non-significantly different trend was observed for AQP3 mRNA levels. Full length cDNAs were then used to generate AQP3 and AQP15 mRNAs for microinjection into Xenopus oocytes. Both AQP3- and AQP15- microinjected oocytes exhibited significantly elevated apparent water permeability compared to control oocytes at neutral pH. The apparent water permeability was mercury-inhibitable, significantly so in the case of AQP3. AQP3 microinjected oocytes showed pH sensitivity in their apparent water permeability, showing a lack of permeability at acidic pH values. The Carboxyl-terminal derived amino acid sequences of AQP3 and AQP15 were used to generate rabbit affinity-purified polyclonal antibodies. Western blots with the antibodies showed a band of 31.3 kDa for AQP3 in the kidney, with minor bands at 26, 24 and 21 kDa. For AQP15 a band of 26 kDa was seen in gill and kidney. Fainter bands at 28 and 24 kDa were also seen in the kidney. There was also some higher molecular weight banding. None of the bands were seen when the antibodies were pre- blocked with their peptide antigens. Immunohistochemical localization studies were also performed in the gill and spiral valve intestine. In the gill, AQP15 antibody staining was seen sporadically in the membranes of surface epithelial cells of the secondary lamellae. Tyramide amplification of signals was employed in the spiral valve intestine. Tyramide-amplified AQP3 antibody staining was observed in the basal membrane of the invaginated epithelial cell layer of secondary intestinal folds in luminal surface of either the side wall of the spiral valve intestine or in internal valve tissue 'flaps'. For the AQP15 antibody, tyramide-amplified staining was instead found on the apical and to a lesser extent the lateral membranes of the same invaginated epithelial cell layer. The localization of AQP3 and AQP15 in the spiral valve intestine suggests that a trans-cellular water absorption pathway may exist in this tissue.

Generalists as Clinical Physiologists: Bringing Science Back to the Bedside.

BACKGROUND: Few generalists engage in basic science research or feel comfortable teaching physiology at the bedside. This may reflect a lack of understanding or confidence teaching physiologic principles. AIM: To inspire general internists to relearn and teach physiology in clinical practice. SETTING: An active biomedical research laboratory. PARTICIPANTS: We educated 67 faculty participants (4 primary care, 59 hospitalists, and 4 other specialties) from 24 medical centers, representing 17 states. PROGRAM DESCRIPTION: The 5-day course was structured around re-learning basic physiology principles and developing teaching skills. Participants engaged in hands-on experiments through 4 modules using aquatic species, each paired with a physiology content primer. Participants also developed teaching scripts based on their experiments. PROGRAM EVALUATION: Post-course surveys revealed that 97% felt confident teaching physiology at the bedside, 100% felt the course enhanced their understanding of the mechanisms of disease, and there was a significant improvement in self-reported teaching ability. DISCUSSION: An immersive, hands-on faculty development course that integrated physiology with clinical decision-making increased participants' comfort level and self-rated ability to teach and incorporate physiology in their clinical work. We believe faculty development is one potential solution to the growing chasm between clinicians and scientists in general medicine.

Molecular mechanisms of voiding dysfunction in a novel mouse model of acute urinary retention.

Acute urinary retention (AUR) is a common urological emergency and affects a significant patient population. The inability to eliminate urine may lead to permanent damage to the bladder's structure and functioning. However, we know little about the underlying molecular sequelae to the urine retention. To closely mirror the potential high pressures that patients with AUR could experience, we catheterized anesthetized female mice via the urethra and filled the bladder by pumping saline (25 µL/min) into the bladder lumen to 50 cm or 80 cm water pressure. A water column with designated height (50 or 80 cm) was then adjusted to maintain constant pressure in the bladder lumen for 30 minutes. Functional and morphological evaluations were performed from 0 to 24 hours after AUR treatment. Mice exhibited incontinence and overactivity with diminished voiding pressure. Significant injury was confirmed which revealed bladders with disrupted urothelial barrier, edematous lamina propria, and distorted muscle bundles. Bladder smooth muscle (BSM) from pressure-treated mice have significantly diminished contraction force, suggesting that bladder voiding dysfunction can be attributed to impaired BSM contractility. Indeed, dysregulation of acetylcholine and purinergic signaling pathways were demonstrated, indicating that reduced efficacy of these pathways contributes to impaired BSM contractility. Finally, altered expression of ß1-integrin and extracellular matrix mediated mechanotransduction pathways were detected, suggesting a profound remodeling process. These data demonstrated an easy to perform, quantifiable, and reproducible AUR mouse model, which mimics well the characteristics of human AUR patients, and our data generate new insights into the molecular mechanisms that occur following AUR.

Niacinamide May Be Associated with Improved Outcomes in COVID-19-Related Acute Kidney Injury: An Observational Study.

Background: AKI is a significant complication of coronavirus disease 2019 (COVID-19), with no effective therapy. Niacinamide, a vitamin B3 analogue, has some evidence of efficacy in non-COVID-19-related AKI. The objective of this study is to evaluate the association between niacinamide therapy and outcomes in patients with COVID-19-related AKI. Methods: We implemented a quasi-experimental design with nonrandom, prospective allocation of niacinamide in 201 hospitalized adult patients, excluding those with baseline eGFR <15 ml/min per 1.73 m2 on or off dialysis, with COVID-19-related AKI by Kidney Disease Improving Global Outcomes (KDIGO) criteria, in two hospitals with identical COVID-19 care algorithms, one of which additionally implemented treatment with niacinamide for COVID-19-related AKI. Patients on the niacinamide protocol (B3 patients) were compared against patients at the same institution before protocol commencement and contemporaneous patients at the non-niacinamide hospital (collectively, non-B3 patients). The primary outcome was a composite of death or RRT. Results: A total of 38 out of 90 B3 patients and 62 out of 111 non-B3 patients died or received RRT. Using multivariable Cox proportional hazard modeling, niacinamide was associated with a lower risk of RRT or death (HR, 0.64; 95% CI, 0.40 to 1.00; P=0.05), an association driven by patients with KDIGO stage-2/3 AKI (HR, 0.29; 95% CI, 0.13 to 0.65; P=0.03; P interaction with KDIGO stage=0.03). Total mortality also followed this pattern (HR, 0.17; 95% CI, 0.05 to 0.52; in patients with KDIGO stage-2/3 AKI, P=0.002). Serum creatinine after AKI increased by 0.20 (SEM, 0.08) mg/dl per day among non-B3 patients with KDIGO stage-2/3 AKI, but was stable among comparable B3 patients (+0.01 [SEM, 0.06] mg/dl per day; P interaction=0.03). Conclusions: Niacinamide was associated with lower risk of RRT/death and improved creatinine trajectory among patients with severe COVID-19-related AKI. Larger randomized studies are necessary to establish a causal relationship.

Disruption of Cav1.2-mediated signaling is a pathway for ketamine-induced pathology.

The general anesthetic ketamine has been repurposed by physicians as an anti-depressant and by the public as a recreational drug. However, ketamine use can cause extensive pathological changes, including ketamine cystitis. The mechanisms of ketamine's anti-depressant and adverse effects remain poorly understood. Here we present evidence that ketamine is an effective L-type Ca2+ channel (Cav1.2) antagonist that directly inhibits calcium influx and smooth muscle contractility, leading to voiding dysfunction. Ketamine prevents Cav1.2-mediated induction of immediate early genes and transcription factors, and inactivation of Cav1.2 in smooth muscle mimics the ketamine cystitis phenotype. Our results demonstrate that ketamine inhibition of Cav1.2 signaling is an important pathway mediating ketamine cystitis. In contrast, Cav1.2 agonist Bay k8644 abrogates ketamine-induced smooth muscle dysfunction. Indeed, Cav1.2 activation by Bay k8644 decreases voiding frequency while increasing void volume, indicating Cav1.2 agonists might be effective drugs for treatment of bladder dysfunction.

Micturition video thermography in awake, behaving mice.

BACKGROUND: Our understanding of the neural circuits controlling micturition and continence is constrained by a paucity of techniques for measuring voiding in awake, behaving mice. NEW METHOD: To facilitate progress in this area, we developed a new, non-invasive assay, micturition video thermography (MVT), using a down-facing thermal camera above mice on a filter paper floor. RESULTS: Most C57B6/J mice void infrequently, with a stereotyped behavioral sequence, and usually in a corner. The timing of each void is indicated by the warm thermal contrast of freshly voided urine. Over the following 10-15 min, urine cools to ∼3 °C below the ambient temperature and spreads radially in the filter paper. By measuring the area of cool contrast comprising this "thermal void spot," we can derive the initially voided volume. Thermal videos also reveal mouse behaviors including a home-corner preference apart from void spots, and a stereotyped, seconds-long pause while voiding. COMPARISON WITH EXISTING METHODS AND CONCLUSIONS: MVT is a robust, non-invasive method for measuring the timing, volume, and location of voiding. It improves on an existing technique, the void spot assay, by adding timing information, and unlike the cystometrogram preparation, MVT does not require surgical catheterization. Combining MVT with current neuroscience techniques will improve our understanding of the neural circuits that control continence, which is important for addressing the growing number of patients with urinary incontinence as the population ages.

Urological complications of obesity and diabetes in males and females of three mouse models: temporal manifestations.

Diabetic bladder dysfunction is a frequent complication of diabetes. Although many mouse models of diabetes now exist, there has been little systematic effort to characterize them for the timing of onset and severity of bladder dysfunction. We monitored metabolic status and tested bladder function by void spot assay and limited anesthetized cystometry in both male and female mice of three models of obesity and diabetes: a type 1 diabetes model (the Akita mouse) and two type 2 diabetes models [the diet-induced obese (DIO) model and the ob/ob mouse]. Akita mice had insulin pellets implanted subcutaneously every 3 mo to mimic poorly controlled type 1 diabetes in humans. Mice were hyperglycemic by 48 days after implants. Female mice exhibited no bladder dysfunction at any age up to 20 mo and gained weight normally. In contrast, by 7 mo, male Akita mice developed a profound polyuria and failed to show normal weight gain. There were no observable signs of bladder dysfunction in either sex. DIO mice on high/low-fat diets for 16 mo exhibited mild hyperglycemia in female mice (not in male mice), mild weight gain, and no evidence of bladder dysfunction. Ob/ob mice were followed for 8 mo and became extremely obese. Male and female mice were glucose intolerant, insulin intolerant, and hyperinsulinemic at 4 mo. By 8 mo, their metabolic status had improved but was still abnormal. Urine volume increased in male mice but not in female mice. Bladder dysfunction was observed in the spotting patterns of female mice at 4 and 6 mo of age, resolving by 8 mo. We conclude there are dramatic sex-related differences in lower urinary tract function in these models. Male Akita mice may be a good model for polyuria-related bladder remodeling, whereas female ob/ob mice may better mimic storage problems related to loss of outlet control in a setting of type 2 diabetes complicated by obesity.

Non-Crh Glutamatergic Neurons in Barrington's Nucleus Control Micturition via Glutamatergic Afferents from the Midbrain and Hypothalamus.

Lower urinary tract symptoms (LUTS) are exceptionally common and debilitating, and they are likely caused or exacerbated by dysfunction of neural circuits controlling bladder function. An incomplete understanding of neural control of bladder function limits our ability to clinically address LUTS. Barrington's nucleus (Bar) provides descending control of bladder and sphincter function, and its glutamatergic neurons expressing corticotropin releasing hormone (BarCrh/Vglut2) are implicated in bladder control. However, it remains unclear whether this subset of Bar neurons is necessary for voiding, and the broader circuitry providing input to this control center remains largely unknown. Here, we examine the contribution to micturition behavior of BarCrh/Vglut2 neurons relative to the overall BarVglut2 population. First, we identify robust, excitatory synaptic input to Bar. Glutamatergic axons from the periaqueductal gray (PAG) and lateral hypothalamic area (LHA) intensely innervate and are functionally connected to Bar, and optogenetic stimulation of these axon terminals reliably provokes voiding. Similarly, optogenetic stimulation of BarVglut2 neurons triggers voiding, whereas stimulating the BarCrh/Vglut2 subpopulation causes bladder contraction, typically without voiding. Next, we genetically ablate either BarVglut2 or BarCrh/Vglut2 neurons and found that only BarVglut2 ablation replicates the profound urinary retention produced by conventional lesions in this region. Fiber photometry recordings reveal that BarVglut2 neuron activity precedes increased bladder pressure, while activity of BarCrh/Vglut2 is phase delayed. Finally, deleting Crh from Bar neurons has no effect on voiding and related bladder physiology. Our results help identify the circuitry that modulates Bar neuron activity and identify subtypes that may serve different roles in micturition.

Targetable purinergic receptors P2Y12 and A2b antagonistically regulate bladder function.

Abnormalities in purine availability or purinergic receptor density are commonly seen in patients with lower urinary tract symptoms (LUTS), but the underlying mechanisms relating altered receptor function to LUTS are unknown. Here we provide extensive evidence for the reciprocal interplay of multiple receptors responding to ATP, ADP (adenosine diphosphate), and adenosine, agonists that regulate bladder function significantly. ADP stimulated P2Y12 receptors, causing bladder smooth muscle (BSM) contraction, whereas adenosine signaling through potentially newly defined A2b receptors, actively inhibited BSM purinergic contractility. The modulation of adenylyl cyclase-cAMP signaling via A2b and P2Y12 interaction actively regulated bladder contractility by modulating intracellular calcium levels. KO mice lacking the receptors display diametrically opposed bladder phenotypes, with P2Y12-KO mice exhibiting an underactive bladder (UAB) phenotype with increased bladder capacity and reduced voiding frequency, whereas A2b-KO mice have an overactive bladder (OAB), with decreased capacity and increased voiding frequency. The opposing phenotypes in P2Y12-KO and A2b-KO mice not only resulted from dysregulated BSM contractility, but also from abnormal BSM cell growth. Finally, we demonstrate that i.p. administration of drugs targeting P2Y12 or A2b receptor rescues these abnormal phenotypes in both KO mice. These findings strongly indicate that P2Y12 and A2b receptors are attractive therapeutic targets for human patients with LUTS.

Void spot assay: recommendations on the use of a simple micturition assay for mice.

Investigators have for decades used mouse voiding patterns as end points for studying behavioral biology. It is only recently that mouse voiding patterns were adopted for study of lower urinary tract physiology. The spontaneous void spot assay (VSA), a popular micturition assessment tool, involves placing a mouse in an enclosure lined by filter paper and quantifying the resulting urine spot pattern. The VSA has advantages of being inexpensive and noninvasive, but some investigators challenge its ability to distinguish lower urinary tract function from behavioral voiding. A consensus group of investigators who regularly use the VSA was established by the National Institutes of Health in 2015 to address the strengths and weaknesses of the assay, determine whether it can be standardized across laboratories, and determine whether it can be used as a surrogate for evaluating urinary function. Here we leverage experience from the consensus group to review the history of the VSA and its uses, summarize experiments to optimize assay design for urinary physiology assessment, and make best practice recommendations for performing the assay and analyzing its results.

Role of P2X4 Receptor in Mouse Voiding Function.

Purinergic signalling plays an important role in the regulation of bladder smooth muscle (BSM) contractility, and P2X4 receptor is expressed in the bladder wall, where it may act by forming heteromeric receptors with P2X1, the major purinergic force-generating muscle receptor. To test this hypothesis, we examined mouse BSM contractile properties in the absence and presence of selective P2X1 (NF449 & NF279) and P2X4 antagonists (5-BDBD). These drugs inhibited BSM purinergic contraction only partially, suggesting the possibility of a heteromeric receptor. However, carefully controlled co-immunoprecipitation experiments indicated that P2X1 and P2X4 do not form physically linked heteromers. Furthermore, immunofluorescence staining showed that P2X4 is not present in mouse BSM per se, but in an unknown cellular structure among BSM bundles. To investigate whether deletion of P2X4 could impact voiding function in vivo, P2X4 null mice were characterized. P2X4 null mice had normal bladder weight and morphology, normal voiding spot size and number by voiding spot assay, normal voiding interval, pressure and compliance by cystometrogram, and normal BSM contractility by myography. In conclusion, these data strongly suggest that P2X4 is not present in mouse BSM cells, does not affect smooth muscle contractility and that mice null for P2X4 exhibit normal voiding function.

A Model for Electronic Handoff Between the Emergency Department and Inpatient Units.

BACKGROUND: Patient handoffs between units can introduce risk and time delays. Verbal communication is the most common mode of handoff, but requires coordination between different parties. OBJECTIVE: We present an asynchronous patient handoff process supported by a structured electronic signout for admissions from the emergency department (ED) to the inpatient medicine service. METHODS: A retrospective review of patients admitted to the medical service from July 1, 2011 to June 30, 2015 at a tertiary referral center with 520 inpatient beds and 57,000 ED visits annually. We developed a model for structured electronic, asynchronous signout that includes an option to request verbal communication after review of the electronic handoff information. RESULTS: During the 2010 academic year (AY) all admissions used verbal communication for signout. The following academic year, electronic signout was implemented and 77.5% of admissions were accepted with electronic signout. The rate increased to 87.3% by AY 2014. The rate of transfer from floor to an intensive care unit within 24 h for the year before and 4 years after implementation of the electronic signout system was collected and calculated with 95% confidence interval. There was no statistically significant difference between the year prior and the years after the implementation. CONCLUSIONS: Our handoff model sought to maximize the opportunity for asynchronous signout while still providing the opportunity for verbal signout when deemed necessary. The process was rapidly adopted with the majority of patients being accepted electronically.

Salt and water: not so simple.

It has long been viewed that the maintenance of osmotic balance in response to high salt intake is a passive process that is mediated largely by increased water consumption to balance the salt load. Two studies in this issue of the JCI challenge this notion and demonstrate that osmotic balance in response to high salt intake involves a complex regulatory process that is influenced by hormone fluctuation, metabolism, food consumption, water intake, and renal salt and water excretion. Rakova et al. report the unexpected observation that long-term high salt intake did not increase water consumption in humans but instead increased water retention. Moreover, salt and water balance was influenced by glucocorticoid and mineralocorticoid fluctuations. Kitada et al. extend upon these findings in mouse models and determined that increased urea and a corresponding increase in urea transporters in the renal medulla as the result of increased protein intake promote the water retention that is needed to achieve osmotic homeostasis. Together, the results of these two studies lay the groundwork for future studies to determine how, in the face of chronic changes in salt intake, humans maintain volume and osmotic homeostasis.