Geriatric assessment improves prediction of surgical outcomes in older adults undergoing pancreaticoduodenectomy: a prospective cohort study.

OBJECTIVE: To prospectively evaluate the additional value of geriatric assessment (GA) for predicting surgical outcomes in a cohort of older patients undergoing a pancreaticoduodenectomy (PD) for pancreatic tumors. BACKGROUND: Older patients are less often referred for possible PD. Standard preoperative assessments may underestimate the likelihood of significant adverse outcomes. The prospective utility of validated GA has not been studied in this group. METHODS: PD-eligible patients were enrolled in a prospective outcome study. Standard preoperative assessments were recorded. Elements of validated GA were also measured, including components of Fried's model of frailty, the Vulnerable Elders Survey (VES-13), and the Short Physical Performance Battery (SPPB). All postoperative adverse events were recorded, systematically reviewed, and graded using the Clavien-Dindo system by a surgeon blinded to the GA results. Multivariate regression analyses were conducted. RESULTS: Seventy-six older patients underwent a PD. Significant unrecognized vulnerability was identified at the baseline: Fried's "exhaustion" (37.3%), SPPB <10 (28.5%), and VES-13 >3 (15.4%). Within 30 days of PD, 46% experienced a severe complication (Clavien-Dindo grade ≥III). In regression analyses controlling for age, the body mass index, the American Society of Anesthesiologists score, and comorbidity burden, Fried's "exhaustion" predicted major complications [odds ratio (OR) = 4.06; P = 0.01], longer hospital stays (ß = 0.27; P = 0.02), and surgical intensive care unit admissions (OR = 4.30; P = 0.01). Both SPPB (OR = 0.61; P = 0.04) and older age predicted discharge to a rehabilitation facility (OR = 1.1; P < 0.05) and age correlated with a lower likelihood of hospital readmission (OR = 0.94; P = 0.02). CONCLUSIONS: Controlling for standard preoperative assessments, worse scores on GA prospectively and independently predicted important adverse outcomes. Geriatric assessment may help identify older patients at high risk for complications from PD.

The molecular basis for modulation of human Vγ9Vδ2 T cell responses by CD277/butyrophilin-3 (BTN3A)-specific antibodies.

Human Vγ9Vδ2 T cells are well known for their rapid and potent response to infection and tumorigenesis when in the presence of endogenous or exogenous phosphoisoprenoids. However, the molecular mechanisms behind the activation of this γδ T cell population remains unclear. Evidence pointing to a role for the CD277/butyrophilin-3 (BTN3A) molecules in this response led us to investigate the structures of these molecules and their modifications upon binding to an agonist antibody (20.1) that mimics phosphoisoprenoid-mediated Vγ9Vδ2 activation and an antagonist antibody (103.2) that inhibits this reactivity. We find that the three BTN3A isoforms: BTN3A1, BTN3A2, and BTN3A3, have high structural homology to the B7 superfamily of proteins and exist as V-shaped homodimers in solution, associating through the membrane proximal C-type Ig domain. The 20.1 and 103.2 antibodies bind to separate epitopes on the BTN3A Ig-V domain with high affinity but likely with different valencies based on their binding orientation. These structures directly complement functional studies of this system that demonstrate that BTN3A1 is necessary for Vγ9Vδ2 activation and begin to unravel the extracellular events that occur during stimulation through the Vγ9Vδ2 T cell receptor.

Impaired replication dynamics at the FRA3B common fragile site.

Chromosomal common fragile sites (CFSs) are genetically unstable regions of the genome that are induced by conditions that impair DNA replication. In this report, we show that treatment with the DNA polymerase inhibitor, aphidicolin (APH), slows the replication rate throughout S phase. To investigate the unusual sensitivity of CFSs to APH-induced replication stress, we examined replication dynamics within a 50 kb region of the most frequently expressed CFS, FRA3B. We mapped four origins of replication, ori 1-4, using two independent methods. In untreated cells, we detected significantly less newly replicated DNA at FRA3B ori 1-3, as compared with three control origins located within non-fragile regions (NCFSs). In APH-treated cells, all FRA3B and control origins tested were active; however, there was a significant increase of nascent strand DNA at the control origins and, to a lesser extent, at the FRA3B ori 1-3. On the basis of these observations and the theoretical modeling of the nascent strand abundance assay developed in this study, we hypothesize that CFS origins may be less efficient, and that APH treatment slows replication fork movement near these origins to a greater extent, resulting in impaired DNA replication and, ultimately, leading to the genetic instability characteristic of CFSs.

High-throughput mapping of origins of replication in human cells.

Mapping origins of replication has been challenging in higher eukaryotes. We have developed a rapid, genome-wide method to map origins of replication in asynchronous human cells by combining the nascent strand abundance assay with a highly tiled microarray platform, and we validated the technique by two independent assays. We applied this method to analyse the enrichment of nascent DNA in three 50-kb regions containing known origins of replication in the MYC, lamin B2 (LMNB2) and haemoglobin beta (HBB) genes, a 200-kb region containing the rare fragile site, FRAXA, and a 1,075-kb region on chromosome 22; we detected most of the known origins and also 28 new origins. Surprisingly, the 28 new origins were small in size and located predominantly within genes. Our study also showed a strong correlation between origin replication timing and chromatin acetylation.

The role of late/slow replication of the FRA16D in common fragile site induction.

The FRA16D, at 16q23, spans the WWOX gene and is one of the most highly expressed common fragile sites observed when DNA replication is perturbed by aphidicolin. Several lines of evidence suggest that fragile sites are regions of DNA that are unusually sensitive to interference during replication. We have determined that the FRA16D alleles replicate in a synchronous fashion and that replication of these sequences occurs primarily in late S phase extending into G2 phase. Exposure to aphidicolin, an inhibitor of DNA polymerase alpha, results in a modest increase in cells with replication of FRA16D sequences in early S phase. This may represent initiation of replication in early S phase coupled with slow replication progression, or, alternatively, these cells may have passed through mitosis, entered the G1-S phase of the next cell cycle, and initiated replication/repair. Our results support a model in which common fragile sites are sequences that may initiate replication in early-mid S phase but are slow to complete replication, and the chromosomal breaks and gaps observed in metaphase cells result from unreplicated DNA.