Resistance to small-molecule CCR5 inhibitors arises when HIV-1 variants acquire the ability to use inhibitor-bound CCR5 while still recognizing free CCR5. Two isolates, CC101.19 and D1/85.16, became resistant via four substitutions in the gp120 V3 region and three in the gp41 fusion peptide (FP), respectively. The binding characteristics of a panel of monoclonal antibodies (MAbs) imply that several antigenic forms of CCR5 are expressed at different levels on the surfaces of U87-CD4-CCR5 cells and primary CD4؉ T cells, in a cell-typedependent manner. CCR5 binding and HIV-1 infection inhibition experiments suggest that the two CCR5 inhibitor-resistant viruses altered their interactions with CCR5 in different ways. As a result, both mutants became generally more sensitive to inhibition by CCR5 MAbs, and the FP mutant is specifically sensitive to a MAb that stains discrete cell surface clusters of CCR5 that may correspond to lipid rafts. We conclude that some MAbs detect different antigenic forms of CCR5 and that inhibitor-sensitive and -resistant viruses can use these CCR5 forms differently for entry in the presence or absence of CCR5 inhibitors.The small-molecule CCR5 inhibitors maraviroc (MVC) and vicriviroc (VVC) are, or have been, used to treat human immunodeficiency virus type 1 (HIV-1) infection. They bind in the transmembrane helices and stabilize CCR5 in a conformation the viral Env complex cannot use efficiently (14,26,47). Resistant viruses usually gain the ability to enter cells via inhibitor-bound CCR5 while retaining the use of free CCR5 (46, 57). Virus-CCR5 binding involves interactions between the Tyr-sulfated N terminus (NT) and the second extracellular loop (ECL2) of the coreceptor and the 4-stranded bridging sheet and V3 region of the gp120 glycoprotein, respectively (20,21). In the most common genetic route to resistance, multiple sequence changes in V3 make the virus more dependent on the CCR5 NT (4,7,27,(37)(38)(39)55). A much rarer pathway involves changes in the fusion peptide (FP) of the gp41 protein, but the resistance mechanism is unknown (3). These pathways were followed when resistant isolates CC101.19 and D1/85.16 were derived from CC1/85 under selection by two similar inhibitors, AD101 and VVC, in peripheral blood mononuclear cells (PBMCs); the most critical resistance-associated substitutions in the escape mutant viruses were four in V3 and three in the FP (27,33). In this study, we used infectious Env chimeric clones, Res-4V3 derived from CC101.19 and Res-3FP from D1/85.16, together with the parental clones Par-4V3 and Par-3FP, derived from CC1/85, which were chosen based on sequence similarities with Res-4V3 and Res-3FP (7).The HIV-1 coreceptors CCR5 and CXCR4 exist in heterogeneous forms (6, 29), influenced by factors such as posttranslational modifications, coupling to G proteins, and the lipid environment (5,8,15,34,35). CCR5 monoclonal antibodies (MAbs) can vary considerably in how they stain different cell types in a way that is not always explained by CCR5 expression levels (1...

Objective To investigate the modified frailty index (mFI) as a pre-operative predictor of post-operative complications following radical cystectomy in bladder cancer patients. Materials and Methods Patients undergoing radical cystectomy (RC) were identified from the National Surgical Quality Improvement Program (NSQIP) participant use files (2011-2013). The mFI was defined in prior studies with 11 variables based on mapping the Canadian Study of Health and Aging Frailty Index to NSQIP comorbidities and activities of daily living (ADL)s. Modified frailty index groups were determined by the number of risk factors per patient (0, 1, 2, ≥3). Univariate, χ2, independent sample t-test, and logistic regression analyses were performed when appropriate. A sensitivity analysis was performed to determine the mFI value at which Clavien 4 and 5 complications would reach significance. Results Of the 2679 cystectomy patients identified, 31% percent of patients had a mFI of 0, 44% had a mFI of 1, 21% had a mFI of 2, and 4% had a mFI ≥ 3. Overall, 59% of patients experienced a Clavien complication. When stratified at a cutoff of mFI >=2, the overall complication rate was not different (61.7% vs. 58.3%, p=0.1319), but the mFI2 or greater group had a significantly higher rate of Clavien grade 4 or 5 complications (14.6% vs. 8.3%, p<0.001) and overall mortality rate (3.5% vs. 1.8%, p=0.0128) in the 30-day post-operative period. The multivariate logistic regression model showed independent predictors of Clavien grade 4 or 5 complications were age >80 years old (OR, 1.58 [1.11-2.27]), mFI2 (odds ratio [OR], 1.84 [1.28-2.64]), and mFI3 (OR, 2.58 [1.47-4.55]). Conclusions Among patients undergoing radical cystectomy, the mFI can identify those patients at greatest risk for severe complications and mortality. Given that bladder cancer is increasing in prevalence particularly among the elderly, pre-operative risk stratification is crucial to inform decision making about surgical candidacy.

Objective To retrospectively validate and compare a modified frailty index predicting adverse outcomes to other risk stratification tools among patients undergoing urologic oncological surgeries. Materials and Methods The American College of Surgeons National Surgical Quality Improvement Program was queried from 2005–2013 to identify patients undergoing cystectomy, prostatectomy, nephrectomy, and nephroureterectomy. Using the Canadian Study of Health & Aging Frailty Index, 11 variables were matched to the database; 4 were also added due to their relevance in oncology patients. The incidence of mortality, Clavien-Dindo IV complications, and adverse events were assessed with patients grouped according to their modified frailty index score. Results A total of 41,681 cases of patients were identified undergoing surgery for presumed urological malignancy. Patients with a high frailty index score of >0.20 had a 3.70 odds of a Clavien-Dindo IV event (CI: 2.865–4.788, p<0.0005) and a 5.95 odds of 30-day mortality (CI: 3.72–9.51, p<0.0005) in comparison to non-frail patients after adjusting for race, gender, age, smoking history and procedure. Using C-statistics to compare the sensitivity and specificity of the predictive ability of different models per risk stratification tool and Akaiki Information Criteria to assess for the fit of the models with the data, the modified frailty index was comparable or superior to the Charlson Comorbidity Index but inferior to the American Society of Anesthesiologists Risk Class in predicting 30-day mortality or Clavien-Dindo IV events. When the modified frailty index was augmented with the American Society of Anesthesiologists Risk Class, the new index was superior in all regards in comparison to risk stratification tools. Conclusion Existing risk stratification tools may be improved by incorporating variables in our 15 point modified frailty index as well as other factors such as walking speed, exhaustion, and sarcopenia to fully assess frailty. This is relevant in diseases like kidney and prostate cancer, where surveillance and other non-surgical interventions exist as alternatives to a potentially complicated surgery. In these scenarios, our modified frailty index augmented by the American Society of Anesthesiologists Risk Class may help inform which patients do not benefit from surgery although this index needs prospective validation.

Small-molecule CCR5 inhibitors such as vicriviroc (VVC) and maraviroc (MVC) are allosteric modulators that impair HIV-1 entry by stabilizing a CCR5 conformation that the virus recognizes inefficiently. Viruses resistant to these compounds are able to bind the inhibitor-CCR5 complex while also interacting with the free coreceptor. CCR5 also interacts intracellularly with G proteins, as part of its signal transduction functions, and this process alters its conformation. Here we investigated whether the action of VVC against inhibitor-sensitive and -resistant viruses is affected by whether or not CCR5 is coupled to G proteins such as G␣ i . Treating CD4 ؉ T cells with pertussis toxin to uncouple the G␣ i subunit from CCR5 increased the potency of VVC against the sensitive viruses and revealed that VVC-resistant viruses use the inhibitor-bound form of G␣ i -coupled CCR5 more efficiently than they use uncoupled CCR5. Supportive evidence was obtained by expressing a signaling-deficient CCR5 mutant with an impaired ability to bind to G proteins, as well as two constitutively active mutants that activate G proteins in the absence of external stimuli. The implication of these various studies is that the association of intracellular domains of CCR5 with the signaling machinery affects the conformation of the external and transmembrane domains and how they interact with small-molecule inhibitors of HIV-1 entry.

While patients with type 2 PRCC appear to present with more advanced disease than patients with type 1, PRCC subtype does not appear to be an independent predictor of CSS, RFS or OS for treated localized disease.