Classification and Risk Factors for Surgical Site Infections in Radical Cystectomy: A 16-Year Analysis.

Introduction: Surgical site infection (SSI) is a substantial cause of peri-operative morbidity among patients undergoing radical cystectomy (RC). The purpose of this study was to identify the risk factors of SSI after RC and to classify and characterize treatment of SSIs. Methods: We retrospectively analyzed peri-operative characteristics and SSI, for patients undergoing RC from 2007 to 2022. Patients were stratified by SSI versus no SSI and differences were assessed. Uni-variable/multi-variable logistic regression analyses were performed to identify factors associated with SSI. SSIs were categorized by the Centers for Disease Control and Prevention (CDC) type: Superficial incisional, deep incisional, and organ/space confined. Results: Three hundred and ninety-eight patients had RC, 279 open, and 119 robotic; 78 (19.6%) developed SSI. Cohorts were similar demographically. Length of stay (LOS) was longer in the SSI cohort (8.8 d versus 12.4 d, p < 0.001), and body mass index (BMI) was greater in patients with SSI (24.34 vs. 25.39, p = 0.0003). On uni-variable analysis, age, gender, Charlson Comorbidity Index, diabetes mellitus, diversion, odds ratio (OR) time, blood loss, and open versus robotic technique were not substantial SSI predictors. BMI was an independent risk factor for SSI on both uni-variable (OR: 1.07, 95% confidence interval [CI]: 1.018-1.115, p = 0.0061) and multi-variable analysis (OR: 1.06, 95% CI: 1.009-1.109, p = 0.02) for 10 (12.8%) and 24 (30.8%) superficial and deep-incisional SSIs, respectively. Superficial wound SSI was treated conservatively with 60% receiving antibiotic agents and no procedural intervention. Deep SSIs received antibiotic agents and 50% required surgical intervention. There were 44 (56.4%) organ/space SSIs, and the most common treatment was antibiotic agents (100%) and IR drain placement (30, 68.2%). Conclusion: In patients undergoing RC, BMI was an independent risk factor for SSI. Type of the surgical procedure, robotic versus open, was not predictive of SSI. LOS was longer for patients with SSI. SSI was managed differently depending on CDC classification.

Mapping of exogenous choline uptake and metabolism in rat glioblastoma using deuterium metabolic imaging (DMI).

Introduction: There is a lack of robust metabolic imaging techniques that can be routinely applied to characterize lesions in patients with brain tumors. Here we explore in an animal model of glioblastoma the feasibility to detect uptake and metabolism of deuterated choline and describe the tumor-to-brain image contrast. Methods: RG2 cells were incubated with choline and the level of intracellular choline and its metabolites measured in cell extracts using high resolution 1H NMR. In rats with orthotopically implanted RG2 tumors deuterium metabolic imaging (DMI) was applied in vivo during, as well as 1 day after, intravenous infusion of 2H9-choline. In parallel experiments, RG2-bearing rats were infused with [1,1',2,2'-2H4]-choline and tissue metabolite extracts analyzed with high resolution 2H NMR to identify molecule-specific 2H-labeling in choline and its metabolites. Results: In vitro experiments indicated high uptake and fast phosphorylation of exogenous choline in RG2 cells. In vivo DMI studies revealed a high signal from the 2H-labeled pool of choline + metabolites (total choline, 2H-tCho) in the tumor lesion but not in normal brain. Quantitative DMI-based metabolic maps of 2H-tCho showed high tumor-to-brain image contrast in maps acquired both during, and 24 h after deuterated choline infusion. High resolution 2H NMR revealed that DMI data acquired during 2H-choline infusion consists of free choline and phosphocholine, while the data acquired 24 h later represent phosphocholine and glycerophosphocholine. Discussion: Uptake and metabolism of exogenous choline was high in RG2 tumors compared to normal brain, resulting in high tumor-to-brain image contrast on DMI-based metabolic maps. By varying the timing of DMI data acquisition relative to the start of the deuterated choline infusion, the metabolic maps can be weighted toward detection of choline uptake or choline metabolism. These proof-of-principle experiments highlight the potential of using deuterated choline combined with DMI to metabolically characterize brain tumors.

Prostein expression on circulating tumor cells as a prognostic marker in metastatic castration-resistant prostate cancer.

BACKGROUND: Identification of emerging molecular biomarkers on circulating tumor cells (CTCs) represents an attractive feature of liquid biopsy that facilitates precision and tailored medicine in the management of metastatic castration-resistant prostate cancer (mCRPC). Prostein is an androgen-regulated transmembrane protein with high prostate specificity. Prostein-positive circulating tumor cell (CTC) was recently suggested to have diagnostic potential; however, no study has been conducted to evaluate its prognostic value in mCRPC. METHODS: CTCs from mCRPC patients were enumerated using the CellSearch System. Prostein-positive CTCs were identified by immunostaining results. The relationships between prostein expression on CTCs and PSA response rate, PSA progression-free survival (PSA-PFS), radiographic progression-free survival (PFS), and overall survival (OS) were tested by Fisher's exact test or evaluated using Kaplan-Meier and multivariate Cox analyses. RESULTS: Prostein-positive CTCs were identified in 31 of 87 baseline samples from mCRPC patients and 16 of 51 samples collected at the first follow-up visit. PSA response rates were significantly lower in baseline prostein-positive patients (0%, 0/31) than in prostein-negative patients (19.6%, 11/56) (p = 0.007). The 31 prostein-positive patients had significantly shorter PSA-PFS (p < 0.001), radiographic PFS (p < 0.001), and OS (p = 0.018), compared to the 56 prostein-negative patients at baseline. The association with PSA-PFS maintained its significance (p = 0.028) in multivariate analyses. Analyzing prostein expression at the first follow-up as well as the conversion of prostein expression from baseline to follow-up samples not only confirmed the association with PSA-PFS, but also demonstrated prognostic significance with OS. CONCLUSION: Our study provides the first evidence to support the potential of prostein expression on CTCs to serve as a novel prognostic marker in mCRPC patients. Future large-scale prospective studies are needed to validate our findings.

Comparison of long-term outcomes in a 10-year experience of robotic cystectomy vs. open cystectomy.

To compare the outcomes of robotic-assisted (RARC) vs. open radical cystectomy (ORC) at a single academic institution. We retrospectively identified patients undergoing radical cystectomy for urothelial carcinoma of the bladder at our institution from 2007 to 2017. Data collected included age, sex, Body Mass Index (BMI), Charlson Age-Adjusted Comorbidity Index (CCI), final pathologic stage, surgical margins, lymph-node yield, estimated blood loss (EBL), 90-day complication rate, and length of stay (LOS). We evaluated overall survival (OS) and recurrence-free survival (RFS). Multivariable Cox proportional hazard models were used to adjust for covariates. We identified 232 patients (73 RARC, 159 ORC) who underwent radical cystectomy. Patients who underwent RARC were older (71.8 vs. 67.5, p < 0.05) and had higher CCI scores (6.2 vs. 5.3, p < 0.05). In comparing perioperative outcomes, RARC patients had lower EBL (500 vs. 850, p < 0.01), lower blood transfusion rate (p < 0.01), and lower lymph-node yield (12 vs. 20, p < 0.01), and higher ICU admission rate (29% vs. 16% p < 0.01). There was no difference in BMI (p = 0.93), sex (p = 0.28), final pathological stage (p = 0.35), positive surgical margins (p = 0.47), complications (p = 0.58), or LOS (p = 0.34). Kaplan-Meier analysis showed no difference in OS (p = 0.26) or RFS (p = 0.86). There was no difference in restricted mean survival time for OS (53 vs. 56 months, p = 0.81) or for RFS (65 vs. 64 months, p = 0.90). Cox multivariate regression models showed that surgical approach does not have a significant impact on OS (p = 0.46) or RFS (p = 0.35). Our study indicates that in our 10-year experience, patients undergoing there was no difference between RARC and ORC patients with respect to OS and RFS despite being older and having more comorbidities. Our work supports the importance of patient selection to optimize outcomes.

Natural history of aortic root aneurysms in Marfan syndrome.

BACKGROUND: Cardiovascular complications account for a significant proportion of the shortened lifespan of Marfan syndrome (MFS) patients, with aortic dissection being the most dreadful complication. The aortic root dilates initially in MFS patients, and given its important hemodynamic role, this can lead to aortic regurgitation and poses a substantial risk of aortic dissection. This study seeks to evaluate the natural history of aortic root aneurysms in MFS patients, with a focus on growth rates and correlation of root diameter with the risk of developing aortic complications. METHODS: Seventy-eight patients confirmed to have MFS and aortic root dilatation were retrospectively reviewed, and their aortic root diameters serially analyzed. Annual growth rate estimates and yearly rates of adverse events were computed and correlated with aortic diameter. RESULTS: The mean annual growth rate of the aortic root was estimated to be 0.26±0.05 cm/year (range 0.13 to 0.35 cm). Larger aneurysms grew faster, reaching up to 0.46 cm/year for aneurysms >6 cm. Mean age at onset of aortic dissection was 36±4 years. Annual rates of adverse events (rupture, dissection and death) were obtained using a logistic regression model at sizes 3.5, 4, 4.5, 5, 5.5 and 6 cm. A sharp increase of 23% in the probability of the risk of complications at diameters 5.5 to 6 cm was recognized. CONCLUSIONS: Aortic root aneurysms in MFS patients tend to have a faster expansion rate compared to non-MFS individuals, with aortic root diameter having a significant impact on the yearly risk of developing aortic complications.

Expanding the genetic code of Escherichia coli with phosphotyrosine.

Protein phosphorylation is one of the most important post-translational modifications in nature. However, the site-specific incorporation of O-phosphotyrosine into proteins in vivo has not yet been reported. Endogenous phosphatases present in cells can dephosphorylate phosphotyrosine as a free amino acid or as a protein residue. Therefore, we deleted the genes of five phosphatases from the genome of Escherichia coli with the aim of stabilizing phosphotyrosine. Together with an engineered aminoacyl-tRNA synthetase (derived from Methanocaldococcus jannaschii tyrosyl-tRNA synthetase) and an elongation factor Tu variant, we were able to cotranslationally incorporate O-phosphotyrosine into the superfolder green fluorescent protein at a desired position in vivo. This system will facilitate future studies of tyrosine phosphorylation.

A ketogenic diet increases transport and oxidation of ketone bodies in RG2 and 9L gliomas without affecting tumor growth.

BACKGROUND: The dependence of tumor cells, particularly those originating in the brain, on glucose is the target of the ketogenic diet, which creates a plasma nutrient profile similar to fasting: increased levels of ketone bodies and reduced plasma glucose concentrations. The use of ketogenic diets has been of particular interest for therapy in brain tumors, which reportedly lack the ability to oxidize ketone bodies and therefore would be starved during ketosis. Because studies assessing the tumors' ability to oxidize ketone bodies are lacking, we investigated in vivo the extent of ketone body oxidation in 2 rodent glioma models. METHODS: Ketone body oxidation was studied using (13)C MR spectroscopy in combination with infusion of a (13)C-labeled ketone body (beta-hydroxybutyrate) in RG2 and 9L glioma models. The level of ketone body oxidation was compared with nontumorous cortical brain tissue. RESULTS: The level of (13)C-beta-hydroxybutyrate oxidation in 2 rat glioma models was similar to that of contralateral brain. In addition, when glioma-bearing animals were fed a ketogenic diet, the ketone body monocarboxylate transporter was upregulated, facilitating uptake and oxidation of ketone bodies in the gliomas. CONCLUSIONS: These results demonstrate that rat gliomas can oxidize ketone bodies and indicate upregulation of ketone body transport when fed a ketogenic diet. Our findings contradict the hypothesis that brain tumors are metabolically inflexible and show the need for additional research on the use of ketogenic diets as therapy targeting brain tumor metabolism.

A synthetic tRNA for EF-Tu mediated selenocysteine incorporation in vivo and in vitro.

Incorporation of selenocysteine (Sec) in bacteria requires a UGA codon that is reassigned to Sec by the Sec-specific elongation factor SelB and a conserved mRNA motif (SECIS element). These requirements severely restrict the engineering of selenoproteins. Earlier, a synthetic tRNASec was reported that allowed canonical Sec incorporation by EF-Tu; however, serine misincorporation limited its scope. We report a superior tRNASec variant (tRNAUTuX) that facilitates EF-Tu dependent stoichiometric Sec insertion in response to UAG both in vivo in Escherichia coli and in vitro in a cellfree protein synthesis system. We also demonstrate recoding of several sense codons in a SelB supplemented cell-free system. These advances in Sec incorporation will aid rational design and directed evolution of selenoproteins.