Real-time estimation of nephron activity with a linear measurement system (RENAL-MS) predicts postoperative estimated glomerular filtration rate.

OBJECTIVE: To determine whether a simple point-of-care measurement system estimating renal parenchymal volume using tools ubiquitously available could be used to replace nuclear medicine renal scintigraphy (NMRS) in current clinical practice to predict estimated glomerular filtration rate (eGFR) after nephrectomy by estimating preoperative split renal function. PATIENTS AND METHODS: We performed a retrospective review of patients who underwent abdominal cross-sectional imaging (computed tomography/magnetic resonance imaging) and mercaptoacetyltriglycine (MAG3) NMRS prior to total nephrectomy at a single institution. We developed the real-time estimation of nephron activity with a linear measurement system (RENAL-MS) method of estimating postoperative renal function via the following technique: renal parenchymal volume of the removed kidney relative to the remaining kidney was estimated as the product of renal length and the average of six renal parenchymal thickness measurements. The utility of this value was compared to the utility of the split renal function measured by MAG3 for prediction of eGFR and new onset Stage 3 chronic kidney disease (CKD) at ≥90 days after nephrectomy using uni- and multivariate linear and logistic regression. RESULTS: A total of 57 patients met the study criteria. The median (interquartile range [IQR]) age was 69 (61-80) years. The median (IQR) pre- and postoperative eGFR was 74 (IQR 58-90) and 46 (35-62) mL/min/1.73 m2 , respectively. [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Correlations between actual and predicted postoperative eGFR were similar whether the RENAL-MS or NMRS methods were used, with correlation using RENAL-MS being slightly numerically but not statistically superior (R = 0.82 and 0.76; P = 0.138). Receiver operating characteristic curve analysis using logistic regression estimates incorporating age, sex, and preoperative creatinine to predict postoperative Stage 3 CKD were similar between RENAL-MS and NMRS (area under the curve 0.93 vs. 0.97). [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] CONCLUSION: A point-of-care tool to estimate renal parenchymal volume (RENAL-MS) performed equally as well as NMRS to predict postoperative eGFR and de novo Stage 3 CKD after nephrectomy in our population, suggesting NMRS may not be necessary in this setting.

Robotic Ureteroplasty with Buccal Mucosa Graft for the Management of Complex Ureteral Strictures.

PURPOSE: Surgical management of proximal and mid ureteral strictures that are not amenable to primary excision and anastomosis is challenging. Although a buccal mucosa graft is commonly used during substitution urethroplasty, its use in substitution ureteroplasty is limited. We describe our technique of robotic ureteroplasty with a buccal mucosa graft to manage complex ureteral strictures and we report our outcomes. MATERIALS AND METHODS: We retrospectively reviewed the records of 12 patients who underwent robotic ureteroplasty with a buccal mucosa graft between September 2014 and June 2016. The indication for the procedure was a proximal or mid ureteral stricture not amenable to primary excision and anastomosis. The primary outcomes were clinical success, absent symptoms on ureteral pathology and radiological success, defined as absent ureteral obstruction on retrograde pyelography, renal scan and/or computerized tomography. RESULTS: Four of the 12 patients (33.3%) had a ureteropelvic junction stricture, 4 (33.3%) had a proximal stricture and 4 (33.3%) had a mid ureteral stricture. Eight of the 12 patients (66.7%) had previously undergone failed ureteral reconstruction. Median stricture length was 3 cm (range 2 to 5). Median operative time was 217 minutes (range 136 to 344) and mean estimated blood loss was 100 ml (range 50 to 200). Median length of stay was 1 day (range 1 to 6). At a median followup of 13 months (range 4 to 30) 10 of the 12 cases (83.3%) were clinically and radiologically successful. CONCLUSIONS: Robotic ureteroplasty with a buccal mucosa graft is associated with low inherent morbidity. It is an effective way to manage complex proximal and mid ureteral strictures.

Outcomes of Urethroplasty for Synchronous Anterior Urethral Stricture Utilizing the Trauma and Urologic Reconstruction Network of Surgeons Length, Segment and Etiology Anterior Urethral Stricture Classification System.

OBJECTIVE: To describe the characteristics, management, and functional outcomes of patients with synchronous urethral stricture disease (SUSD) utilizing a multi-institutional cohort. METHODS: Data were collected and assessed from a prospectively maintained, multi-institutional database. Patients who underwent anterior urethroplasty for urethral stricture disease (USD) were included and stratified by the presence or absence of SUSD. USD location and etiology were classified according to the Trauma and Urologic Reconstruction Network of Surgeons Length, Segment and Etiology Anterior Urethral Stricture Classification System. Anterior urethroplasty techniques were recorded for both strictures. Functional failure was compared between groups. RESULTS: One thousand nine hundred eighty-three patients were identified, of whom, 137/1983 (6.9%) had SUSD. The mean primary stricture length for patients with SUSD was 3.5 and 2.6 cm for the secondary stricture. Twelve anterior urethroplasty technique combinations were utilized in treating the 27 different combinations of SUSD. Functional failure was noted in 18/137 (13.1%) patients with SUSD vs 192/1846 (10.4%) patients with solitary USD, P = .3. SUSD was not associated with increased odds of functional failure. S classifications: S1b, P = .003, S2a, P = .001, S2b, P = .01 and S2c, P = .02 and E classifications: E3a, P = .004 and E6, P = .03, were associated with increased odds of functional failure. CONCLUSION: Repair of SUSD in a single setting does not increase the risk of functional failure compared to patients with solitary USD. Increasing S classification, S1b through S2c and E classifications E3a and E6 were associated with increased functional failure. This reinforces the importance of the Trauma and Urologic Reconstruction Network of Surgeons Length, Segment and Etiology Anterior Urethral Stricture Classification System as a necessary tool in large-scale multi-institutional analysis when assessing highly heterogenous patient populations.

The Delayed Nephrogram: Point-of-care Quantitative Measurement, Validation as an Indicator of Obstruction, and Novel Use as a Predictor of Renal Functional Impairment.

BACKGROUND: The diagnostic value of delayed nephrograms on contrast-enhanced computed tomography has not been studied rigorously. OBJECTIVE: To develop a method for quantitatively assessing delayed and diminished nephrograms (DDNs) easily at the point of care and to assess the association of DDNs with renal obstruction and renal function. DESIGN, SETTING, AND PARTICIPANTS: Data were reviewed from 76 patients who underwent a contrast-enhanced computed tomography scan within 30 days of a technetium-99m mercaptoacetyltriglycine diuretic renal scintigraphy (MAG3-DRS) which showed at least one kidney to have normal drainage (T1/2 <10 min) between 2010 and 2021 at a tertiary academic center. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Attenuations of the renal cortex and medulla were measured using circular regions of interest. These attenuations were compared between kidneys to compute several measures of DDN in the kidney with a greater concern for obstruction. Renal parenchymal volume and anterior-posterior renal pelvis diameter (APD) were estimated using simple linear measurements. Inter-rater reliability was computed using the intraclass correlation coefficient (ICC), correlations were computed using Spearman's R, and the relationships between DDN, APD, and renal function of the subject kidney were estimated using linear regression. RESULTS AND LIMITATIONS: Measures of DDN were highly reliable between raters (ICC 0.71-0.87). DDN was almost always associated with prolonged drainage on MAG3-DRS (90-100%); however, 33-52% of patients with prolonged drainage on MAG3-DRS had no appreciable DDN, depending on the measure of the DDN chosen. All measures of DDN were associated with decreased renal function (<0.001). APD did not significantly predict renal function when controlling for a DDN. CONCLUSIONS: DDNs on contrast-enhanced computed tomography are associated with renal obstruction and can easily and accurately be quantified at the point of care. A DDN is more closely associated with renal dysfunction than renal pelvic dilation and therefore may be useful in assessing the severity of upper tract obstruction. PATIENT SUMMARY: In this report, we confirm that a "delayed nephrogram", a classic x-ray finding thought to be associated with kidney blockage, is associated with blockage of the affected kidney. Furthermore, we show that a delayed nephrogram indicates that the affected kidney is not functioning as well as we would expect for a normal kidney of the same size. Since the severity of a delayed nephrogram predicts this decreased function better than the degree of dilation of the kidney, which is a different measurement often used to measure the severity of kidney blockage, the delayed nephrogram may be a better way of measuring the severity of kidney blockage in clinical practice.

Rethinking the routine: Preoperative laboratory testing among American Society of Anesthesiologists class 1 and 2 patients before low-risk ambulatory surgery in the 2017 National Surgical Quality Improvement Program cohort.

BACKGROUND: Routine preoperative laboratory testing is not recommended for American Society of Anesthesiologists classification 1 or 2 patients before low-risk ambulatory surgery. METHODS: The 2017 National Surgical Quality Improvement Program data set was retrospectively queried for American Society of Anesthesiologists class 1 and 2 patients who underwent low-risk, elective outpatient anorectal, breast, endocrine, gynecologic, hernia, otolaryngology, oral-maxillofacial, orthopedic, plastic/reconstructive, urologic, and vascular operations. Preoperative laboratory testing was defined as any chemistry, hematology, coagulation, or liver function studies obtained ≤30 days preoperatively. Demographics, comorbidities, and outcomes were compared between those with and without testing. The numbers needed to test to prevent serious morbidity or any complication were calculated. Laboratory testing costs were estimated using Centers for Medicare and Medicaid Services data. RESULTS: Of 111,589 patients studied, 57,590 (51.6%) received preoperative laboratory testing; 26,709 (46.4%) had at least 1 abnormal result. Factors associated with receiving preoperative laboratory testing included increasing age, female sex, non-White race/ethnicity, American Society of Anesthesiologists class 2, diabetes, dyspnea, hypertension, obesity, and steroid use. Mortality did not differ between patients with and without testing. The complication rate was 2.5% among tested patients and 1.7% among patients without tests (P < .01). The numbers needed to test was 599 for serious morbidity and 133 for any complication. An estimated $373 million annually is spent on preoperative laboratory testing in this population. CONCLUSION: Despite American Society of Anesthesiologists guidelines, a majority of American Society of Anesthesiologists class 1 and 2 patients undergo preoperative laboratory testing before elective low-risk outpatient surgery. The differences in the rates of complications between patients with and without testing is low. Preoperative testing should be used more judiciously in this population, which may lead to cost savings.

A review of technical progression in the robot-assisted radical prostatectomy.

Since the advent of the robotic surgery, its implementation in urology has been both wide and rapid. Particularly in extirpative surgery for prostate cancer, techniques in robotic-assisted radical prostatectomy have-and continue to-evolve to maximize functional and oncologic outcomes. In this review, we briefly present a historical perspective of the evolution of various robotic techniques, allowing us to contextualize contemporary robotic approaches to radical prostatectomy.

Nephrobiliary fistula resulting from a gunshot wound in a young healthy male: A case report.

Biliary fistulas are most commonly caused by cholelithiasis. Other causes include malignancies and peptic ulcer disease. A biliary fistula caused by a penetrating trauma is a rare entity, and a post-traumatic biliary fistula to the renal collecting system is extremely uncommon. We present an extremely rare case of a post-traumatic nephrobiliary fistula incurred after penetrating trauma that was successfully treated with endoscopic retrograde cholangiopancreatography (ERCP), biliary stents, and percutaneous drainage.

Methylene blue promotes survival and GAP-43 expression of retinal ganglion cells after optic nerve transection.

AIMS: Neurodegeneration of the optic nerve and retinal ganglion cells (RGCs) leads to progressive vision loss. As part of the central nervous system, RGCs show limited ability to regenerate and there is extensive search for neuroprotective agents for optic nerve damage. Methylene blue (MB) exhibits beneficial effects against various neurodegenerative diseases of the central nervous system. However, the mechanisms associated with its putative protection on neuronal survival and regeneration remain obscure. This study used the optic nerve transection model to examine the effects of MB on RGC survival, the expression of regenerative marker GAP-43 in RGCs and microglial activation. MAIN METHODS: Axons of RGCs were injured by cutting the optic nerve. MB was injected intravitreally either immediately post-injury or delayed to 3 days post-injury. Using immunohistochemical staining, surviving RGCs, GAP-43-positive RGCs and microglial cells were quantified in wholemount retinas 7 days post-injury. KEY FINDINGS: Both immediate and delayed (a more clinically realistic situation) intravitreal injection of MB promoted RGC survival. MB also increased the number of GAP-43-positive RGCs, suggesting an enhanced ability of RGCs to regenerate. This was exemplified by the regenerative sprouting of axon-like processes from injured RGCs after MB treatment. The increase in RGC survival and GAP-43 expression correlated with an increase in the number of microglial cells. SIGNIFICANCE: These results reveal that MB has survival-promoting and growth-promoting effects on RGCs after optic nerve injury. Together with the established safety profile of MB in humans, MB is a promising treatment for neurodegeneration and injury of the optic nerve.

Co-localization of hyperphosphorylated tau and caspases in the brainstem of Alzheimer's disease patients.

Hyperphosphorylation of microtubule associated protein tau had limited studies in Alzheimer's disease (AD) brainstem. We compared the distribution and number of neurons with hyperphosphorylated tau in two age groups of AD brainstems with mean ages of 65.4 +/- 5.7 and 91.1 +/- 6.4 years. The degree of co-localization of hyperphosphorylated tau positive cells with either cleaved caspase-3 or cleaved caspase-6 was also quantified. Results showed hyperphosphorylated tau mainly occurred in hypoglossal, dorsal motor vagal, trigeminal sensory/motor nuclei as well as in dorsal raphe, locus coeruleus and substantia nigra. Older AD brainstem consistently had higher density of hyperphosphorylated tau cells. Up to 70% of tau positive cells also displayed either cleaved caspase-3 or caspase-6, and the number of co-localized tau cells in each caspase subfamily group was always higher in older aged group. Some hyperphosphorylated tau cells with cleaved caspases had TUNEL positive nuclei. These findings suggest that these latter cells went through the apoptotic process or DNA fragmentation.

Protection of retinal ganglion cells against optic nerve injury by induction of ischemic preconditioning.

AIM: To explore if ischemic preconditioning (IPC) can enhance the survival of retinal ganglion cells (RGCs) after optic nerve axotomy. METHODS: Twenty-four hours prior to retinal ischemia 60min or axotomy, IPC was applied for ten minutes in groups of (n=72) animals. The survival of RGCs, the cellular expression of heat shock protein 27 (HSP27) and heat shock protein 70 (HSP70) and the numbers of retinal microglia in the different groups were quantified at 7 and 14d post-injury. The cellular expression of HSP27 and HSP70 and changes in the numbers of retinal microglia were quantified to detect the possible mechanism of the protection of the IPC. RESULTS: Ten minutes of IPC promoted RGC survival in both the optic nerve injury (IPC-ONT) and the retinal ischemia 60min (IPC-IR60) groups, examined at 7d and 14d post-injury. Microglial proliferation showed little correlation with the extent of benefit effects of IPC on the rescue of RGCs. The number of HSP27-positive RGCs was significantly higher in the IPC-ONT group than in the sham IPC-ONT group, although the percentage of HSP27-positive RGCs did not significantly differ between groups. For the IPC-IR60 group, neither the number nor the percentage of the HSP27-positive RGCs differed significantly between the IPC and the sham-operated groups. The number of HSP70-positive RGCs was significantly higher for both the IPC-ONT and the IPC-IR60 experimental groups, but the percentages did not differ. CONCLUSION: The induction of IPC enhances the survival of RGCs against both axotomy and retinal ischemia.

Lens epithelial cells promote regrowth of retinal ganglion cells in culture and in vivo.

Lens damage has been demonstrated to promote axonal regeneration of retinal ganglion cells. Various mechanisms associated with this enhancement have been proposed, including macrophage recruitment and stimulatory factors from the lesioned lens. Lens epithelial cells, which become activated as a result of injury, are another potential stimulus. A recent study of co-culturing lens epithelial cells adjacent to retinal explants without direct contact showed that neurites were attracted to grow towards them. We explored the ability of lens epithelial cells to act as a favorable substrate for ganglion cell axonal regeneration, by culturing retinal explants on top of a lens epithelial cell layer, as well as in vivo by transplanting freshly isolated lens epithelial cells to the cut optic nerve. Retinal explants cultured on lens epithelial cells regenerated more and longer neurites than those cultured on either an acellular substrate or a substrate of corneal cells, while lens epithelial cells transplanted to the optic nerve stimulated axons to regenerate in close association with them.

Multifocal Renal Fungal Abscesses.

We report a case of multiple fungal renal abscesses in a 36-year-old woman with a history of diabetes and intravenous substance use disorder. The patient presented with fever and hematuria, and was found to be bacteremic and fungemic. She was initially managed with broad-spectrum antibiotics and antifungals. She remained febrile and imaging on treatment day 14 showed no improvement of the renal abscesses. Thus, a nephrectomy was performed, after which the patient defervesced and follow-up blood cultures were negative. There is a paucity of literature regarding management of multifocal fungal renal abscesses that fail to respond to medical management.

The Origin, Expression, Function and Future Research Focus of a G Protein-coupled Receptor, Mas-related Gene X2 (MrgX2).

Mas-related genes (Mrgs) belong to a large family of G protein-coupled receptor genes found in rodents. Human MRGX proteins are G protein-coupled 7-transmembrane proteins sharing 41-52% amino acid identity with each other, but have no orthologs in rodents. MrgX2 is a member of the MrgX family. MRGX2 is expressed in the small neurons of sensory ganglia and mast cells. It can interact with a series of factors and genes such as the peptides substance P, vasoactive intestinal peptide, cortistatin (CST), proadrenomedullin N-terminal peptide (PAMP), LL-37, PMX-53 and ß-defensins. MRGX2 is related to nociception, adrenal gland secretion and mast cell degranulation. Recent research on MrgX2 provides insights into its role in nociception and anti-microbial activities. This article reviewed the origin, expression and function of MrgX2, and discussed possible future research focus.

Remote ischemic postconditioning promotes the survival of retinal ganglion cells after optic nerve injury.

Ischemic conditioning, the application of a mild ischemic stimulus to an ischemia-sensitive structure like the heart or brain either before (preconditioning) or after (postconditioning) its exposure to a lethal ischemic insult, is known to switch on endogenous protective mechanisms. However, most studies of its neuroprotective effect in the central nervous system (CNS) have focused on ischemic damage or related conditions like hypoxia, while its potential in treating other neural diseases remains uncertain. In particular, the recent discovery of remote ischemic postconditioning whereby mild ischemia applied to a region remote from the target after the main ischemic insult also confers protection offers an attractive paradigm to study its potential in other types of neural injury. Retinal ganglion cells damaged by optic nerve transection undergo extensive cell death. However, application of a series of mild ischemic/reperfusion cycles to the hind limb (limb remote ischemic postconditioning) at 10 min or 6 h after optic nerve cut was found to promote ganglion cell survival at 7 days post-injury, with the 10 min postconditioning still exerting protection at 14 days post-injury. Concomitant with the increased ganglion cell survival, 51 % more ganglion cells expressed the small heat shock protein HSP27, when remote ischemic postconditioning was performed at 10 min post-injury, as compared to the sham conditioning group. Our results highlight the potential of using remote ischemic postconditioning as a noninvasive neuroprotective strategy in different CNS disorders like spinal cord and traumatic brain injury.

Different in vitro toxicity of ribosome-inactivating proteins (RIPs) on sensory neurons and Schwann cells.

OBJECTIVE: To study the neurotoxicity induced by Ricinus communis agglutinin (RCA), ricin A chain (RTA), and trichosanthin (TCS) in vitro. METHODS: Rat neurons and Schwann cells were cultured and real-time up-take of RIPs was traced. TUNEL, Annexin V and DAPI were employed to study the mechanism. RESULTS: The purity of both primary neuronal and Schwann cell cultures attained 80-90%. In neuritis, transport of FITC-RCA was demonstrated, but RTA and TCS were not detected. RCA elicited the strongest TUNEL and annexin V signals in both cultures. RTA evoked a stronger apoptotic signal than TCS in neurons. In contrast, compared with TCS, RTA elicited an attenuated apoptotic reaction in Schwann cells. All internalized RIPs were concentrated in the cytoplasm of the cells and their nuclei were not stained by DAPI. CONCLUSION: The toxicity of these RIPs on neurons is different from that on Schwann cells. Although they enter cells by different mechanisms they all induce apoptosis. These results may find application in in vivo neural lesioning studies and clinical therapy.