Impact of age and medical comorbidity on adjuvant treatment outcomes for stage III colon cancer: a pooled analysis of individual patient data from four randomized, controlled trials.

BACKGROUND: Adjuvant oxaliplatin plus capecitabine or leucovorin/5-fluorouracil (LV/5-FU) (XELOX/FOLFOX) is the standard of care for stage III colon cancer (CC); however, there is disagreement regarding oxaliplatin benefit in patients aged >70. In most analyses, the impact of medical comorbidity (MC) has not been assessed. Efficacy and safety of adjuvant XELOX/FOLFOX versus LV/5-FU were compared with respect to age and MC using pooled data from four randomized, controlled trials, selected for access to patient-level MC data and including commonly endorsed and utilized regimens. PATIENTS AND METHODS: Individual data from patients with stage III CC in NSABP C-08, XELOXA, X-ACT, and AVANT were pooled, excluding bevacizumab-treated patients. Patients were grouped by treatment, MC (low versus high), or age (<70 versus ≥70), and compared for disease-free survival (DFS), overall survival (OS), and adverse events (AEs). Multivariable Cox proportional hazards regression controlled for gender, T stage, and N stage. RESULTS: DFS benefits were shown for XELOX/FOLFOX versus LV/5-FU regardless of age or MC, although benefits were modestly attenuated for patients aged ≥70. Hazard ratios were 0.68 (P < 0.0001) and 0.77 (P < 0.014) for <70 and ≥70 age groups; 0.69 (P < 0.0001) and 0.59 (P < 0.0001) for Charlson Comorbidity Index ≤1 and >1 groups; and 0.70 (P < 0.0001) and 0.58 (P < 0.0001) for National Cancer Institute Combined Index ≤1 and >1 groups. OS was also significantly improved in all groups. Grade 3/4 serious AE rates were comparable across cohorts and MC scores and higher in patients aged ≥70. Oxaliplatin-relevant grade 3/4 AEs, including neuropathy, were comparable across ages and MC scores. CONCLUSIONS: Results further support consideration of XELOX or FOLFOX as standard treatment options for the adjuvant management of stage III CC in all age groups and in patients with comorbidities, consistent with those who were eligible for these clinical trials.

Phylogenetic investigation of enteric bovine coronavirus in Ireland reveals partitioning between European and global strains.

BACKGROUND: Bovine coronavirus is a primary cause of neonatal calf diarrhea worldwide, and is also associated with acute diarrhea in adult cattle during the winter season. There are no reports on molecular characterization of bovine coronavirus in Ireland, and little data exists apart from serological studies. FINDINGS: In this study, 11 neonatal (mean age 9 days) calf BCoV strains from the south of Ireland were collected over a one year period and characterized using molecular methods. The spike gene which encodes a protein involved in viral entry, infectivity and immune response shows the most variability amongst the isolates and was subsequently selected for in depth analysis. Phylogenetic analysis of the spike gene revealed that the Irish strains clustered with novel BCoV strains from Europe in a unique clade, possibly indicating lineage partitioning. Direct analysis of alignments identified amino acid changes in the spike protein unique to the Irish clade. CONCLUSION: Thus, monitoring of bovine coronavirus in Ireland is important as the current isolates in circulation in the south of Ireland may be diverging from the available vaccine strain, which may have implications regarding future BCoV vaccine efficacy.

Stability properties of an ancient plant peroxidase.

Plant (Class III) peroxidases have numerous applications throughout biotechnology but their thermal and oxidative stabilities may limit their usefulness. Horseradish peroxidase isoenzyme C (HRPC) has good catalytic turnover and is moderately resistant to heat and to excess (oxidizing) concentrations of hydrogen peroxide. In contrast, HRP isoenzyme A2 (HRP A2) has better oxidative but poorer thermal stability, while soybean peroxidase (SBP) displays enhanced thermal stability. Intrigued by these variations amongst closely related enzymes, we previously used maximum likelihood methods (with application of Bayesian statistics) to infer an amino acid sequence consistent with their most recent common ancestor, the 'Grandparent' (GP). Here, we report the cloning and expression of active recombinant GP protein in Escherichia coli. GP's half-inactivation temperature was 45 °C, notably less than HRP C's, but its resistance to excess H2O2 was 2-fold greater. This resurrected GP protein enables a greater understanding of plant peroxidase evolution and serves as a test-bed to explore their ancestral properties.

Innovative estimation of survival using log-normal survival modelling on ACCENT database.

BACKGROUND: The ACCENT database, with individual patient data for 20 898 patients from 18 colon cancer clinical trials, was used to support Food and Drug Administration (FDA) approval of 3-year disease-free survival as a surrogate for 5-year overall survival. We hypothesised substantive differences in survival estimation with log-normal modelling rather than standard Kaplan-Meier or Cox approaches. METHODS: Time to relapse, disease-free survival, and overall survival were estimated using Kaplan-Meier, Cox, and log-normal approaches for male subjects aged 60-65 years, with stage III colon cancer, treated with 5-fluorouracil-based chemotherapy regimens (with 5FU), or with surgery alone (without 5FU). RESULTS: Absolute differences between Cox and log-normal estimates with (without) 5FU varied by end point. The log-normal model had 5.8 (6.3)% higher estimated 3-year time to relapse than the Cox model; 4.8 (5.1)% higher 3-year disease-free survival; and 3.2 (2.2)% higher 5-year overall survival. Model checking indicated greater data support for the log-normal than the Cox model, with Cox and Kaplan-Meier estimates being more similar. All three model types indicate consistent evidence of treatment benefit on both 3-year disease-free survival and 5-year overall survival; patients allocated to 5FU had 5.0-6.7% higher 3-year disease-free survival and 5.3-6.8% higher 5-year overall survival. CONCLUSION: Substantive absolute differences between estimates of 3-year disease-free survival and 5-year overall survival with log-normal and Cox models were large enough to be clinically relevant, and warrant further consideration.

Prognostic effect of activated EGFR expression in human colon carcinomas: comparison with EGFR status.

BACKGROUND: Evidence suggests that epidermal growth factor receptor (EGFR)-activation status may better predict the clinical behaviour of colon cancers than does EGFR expression. However, the prognostic effect of phospho-EGFR in primary colon cancer remains undefined. METHODS: Phospho-EGFR (Tyr-1173) and EGFR expression were analysed by immunohistochemistry (IHC) in tissue microarrays of TNM stage II and III colon cancers from completed adjuvant therapy trials (n=388). Staining intensity was scored and correlated with clinicopathological variables, DNA mismatch repair (MMR) status, rates of cell proliferation (Ki-67), apoptosis (caspase-3), and patient survival. RESULTS: Phospho-EGFR expression was detected in 157 of 388 (40%) tumours, whereas EGFR was found in 214 of 361 (59%). Although phospho-EGFR was unrelated to clinicopathological variables, strong EGFR intensity was associated with higher tumour stage (P=0.03). Tumours overexpressing EGFR (P=0.0002) or phospho-EGFR (P=0.015) showed increased Ki-67, but not caspase-3 expression. Phospho-EGFR was not prognostic. EGFR intensity was associated with worse disease-free survival (DFS) (hazard ratio (HR): 1.21 (1.03, 1.41); P=0.019) and overall survival (OS) (HR: 1.19 (1.02, 1.39); P=0.028). Tumours expressing both EGFR and phospho-EGFR had similar survival as EGFR alone. Stage and lymph node number were prognostic for DFS and OS, and histological grade for OS. EGFR was an independent predictor of DFS (P=0.042) after adjustment for stage, histological grade, age, and MMR status. CONCLUSION: Phospho-EGFR and EGFR expression were associated with tumour cell hyperproliferation. Phospho-EGFR was not prognostic, whereas increased EGFR intensity was independently associated with poor DFS.

Skeletal forelimb measurements and hoof spread in relation to asymmetry in the bilateral forelimb of horses.

REASONS FOR PERFORMING STUDY: Research has highlighted a high frequency of skeletal asymmetries in horses. In addition, research into hoof asymmetries has shown that within a bilateral pair, the hoof with the smaller angle is often subjected to greater loading. There has been limited attention paid to understanding compensatory mechanisms for skeletal asymmetries in the horse; the dynamic structure of the hoof could potentially be acting in a compensatory capacity. OBJECTIVES: To investigate the relationship between morphometry of forelimb segments and hoof spread and their incidence of asymmetry. METHODS: Ten bilateral measurements of the hoof and forelimb were taken from 34 leisure horses. The relationship between hoof spread and forelimb segment measurements were analysed using a generalised linear model (GLM). RESULTS: In relation to left hoof spread, the GLM identified significant negative relationships with left side measurements (third metacarpal length, elbow height), and significant positive relationships with right side measurements (fetlock height, third metacarpal length, elbow height). In relation to right hoof spread, the GLM identified significant negative relationship with left elbow height, and significant positive relationships with right side measurements (fetlock height, point of shoulder). The difference between the number of horses larger to the left or to the right was found to be significant for point of shoulder height (chi2 = 4.8, P < 0.05), and highly significant for heel height (chi2 = 953, P < 0.01) and the third metacarpal length (chi2 = 7.26, P < 0.01). CONCLUSIONS AND CLINICAL RELEVANCE: The study demonstrated considerable asymmetry in left-right morphometry of the equine limb. The fact that measurements of hoof spread were significantly associated with limb segment measurements could possibly indicate that an interaction exists. Any asymmetry in hoof spread measurements may suggest unequal loading of the limbs, which in turn may contribute to injuries and reduced performance.

The effect of cereal type and enzyme addition on pig performance, intestinal microflora, and ammonia and odour emissions.

Two 2 × 2 factorial experiments were conducted to investigate the interaction between cereal type (wheat v. barley) and exogenous enzyme supplementation (with or without) on odour and ammonia emissions (experiment 1) and growth performance (experiment 2) in grower-finisher pigs. The enzyme supplement used contained endo-1, 3 (4) - ß- glucanase (EC 3.2.1.6) and endo-1, 4 - ß-xylanase (E.C 3.2.1.8). The diets were formulated to contain similar levels of net energy (9.8 MJ/kg) and lysine (10.0 g/kg). The experimental treatments were as follows: (1) wheat-based diet, (2) wheat-based diet containing a ß-glucanase and ß-xylanase mixed enzyme supplement, (3) barley-based diet and (4) barley-based diet containing a ß-glucanase and ß-xylanase mixed enzyme supplement. In experiment 1, the diets were offered to the pigs for 23 days in sealed pens (eight pigs per pen) and this was repeated four times (n = 4). Odour and ammonia emissions were measured on days 9, 11, 14, 16, 21 and 23 of each replicate period. Odour samples were collected in 20-l Nalophan bags and analysed for odour concentration using an ECOMA Yes/No Olfactometer. Ammonia concentrations in the ventilation air were measured using Dräger tubes. In experiment 2, 220 pigs were group fed in mixed sex pens using single-space feeders (11 pigs per feeder, six boars and five gilts) (n = 5). There was a cereal × enzyme interaction in odour emission rates, ammonia emissions and selected microbial populations in the caecum and colon (P < 0.05). The addition of an enzyme supplement to the barley-based diet increased both odour and ammonia emission, however the addition of an enzyme to the wheat-based diet decreased ammonia emission rates and had no effect on odour emission. Pigs offered the unsupplemented barley-based diet had a significantly (P < 0.05) lower population of Enterobacteriaceae spp. and a higher population of Bifidobacteria spp. compared with enzyme-supplemented barley diets. However, there was no effect of enzyme supplementation in wheat-based diets. In the performance experiment, neither cereal type nor enzyme inclusion had an effect on pig performance or carcass characteristics. In conclusion, the inclusion of an enzyme mix to barley-based diets increased odour and ammonia emissions, while the addition of an enzyme mix to wheat-based diets decreased ammonia emissions.

Calcified occlusion of the right coronary artery in Kawasaki disease: evidence of myocardial ischaemia using cardiac technetium-99m-tetrofosmin perfusion single-photon emission computed tomography.

We report the case of a 14-year-old boy who developed Kawasaki disease at 5 months of age. The patient developed severe aneurysmal disease of both the left and right coronary arteries. He eventually developed total calcified occlusion of the right coronary artery despite long-term treatment with aspirin. Catheterisation showed no antegrade flow into the right coronary artery, with retrograde flow from the left coronary system into the right coronary. At the most recent follow-up he was asymptomatic, with normal exercise tolerance and a negative exercise stress test. Single-photon emission computed tomography (SPECT) myocardial perfusion imaging was carried out during stress and at rest using intravenous persantine (dipyridamole) and technetium-99m tetrofosmin. During stress, there were prominent left ventricular apical and anteroseptal defects, which normalised at rest. SPECT during stress and at rest may detect subclinical ischaemia and influence further management options in such patients.

Oxidative stress induces a prolonged but reversible arrest in p53-null cancer cells, involving a Chk1-dependent G2 checkpoint.

Reactive oxygen species (ROS), the principal mediators of oxidative stress, induce responses such as apoptosis or permanent growth arrest/senescence in normal cells. Moreover, p53 activation itself contributes to ROS accumulation. Here we show that treatment of p53-null cancer cells with sublethal concentrations of ROS triggered an arrest with some morphological similarities to cellular senescence. Different from a classical senescent arrest in G(1), the ROS-induced arrest was predominantly in the G(2) phase of the cell cycle, and its establishment depended at least in part on an intact Chk1-dependent checkpoint. Chk1 remained phosphorylated only during the repair of double strand DNA breaks, after which Chk1 was inactivated, the G(2) arrest was suppressed, and some cells recovered their ability to proliferate. Inhibition of Chk1 by an RNAi approach resulted in an increase in cell death in p53-null cells, showing that the Chk1-dependent G(2) checkpoint protected cells that lacked a functional p53 pathway from oxidative stress. It has been proposed that the induction of a senescent-like phenotype by antineoplastic agents can contribute therapeutic efficacy. Our results indicate that oxidative stress-induced growth arrest of p53-null tumor cells cannot be equated with effective therapy owing to its reversibility and supports the concept that targeting Chk1 may enhance the effects of DNA-damaging agents on cancer progression in such tumors.

Single carbon nanotubes probed by photoluminescence excitation spectroscopy: the role of phonon-assisted transitions.

We study light absorption mechanisms in semiconducting carbon nanotubes using low-temperature, single-nanotube photoluminescence excitation spectroscopy. In addition to purely electronic transitions, we observe several strong phonon-assisted bands due to excitation of one or more phonon modes together with the first electronic state. In contrast with a small width of emission lines (sub-meV to a few meV), most of the photoluminescence excitation features have significant linewidths of tens of meV. All of these observations indicate very strong electron-phonon coupling that allows efficient excitation of electronic states via phonon-assisted processes and leads to ultrafast intraband relaxation due to inelastic electron-phonon scattering.

Ultralong single-wall carbon nanotubes.

Since the discovery of carbon nanotubes in 1991 by Iijima, there has been great interest in creating long, continuous nanotubes for applications where their properties coupled with extended lengths will enable new technology developments. For example, ultralong nanotubes can be spun into fibres that are more than an order of magnitude stronger than any current structural material, allowing revolutionary advances in lightweight, high-strength applications. Long metallic nanotubes will enable new types of micro-electromechanical systems such as micro-electric motors, and can also act as a nanoconducting cable for wiring micro-electronic devices. Here we report the synthesis of 4-cm-long individual single-wall carbon nanotubes (SWNTs) at a high growth rate of 11 microm s(-1) by catalytic chemical vapour deposition. Our results suggest the possibility of growing SWNTs continuously without any apparent length limitation.

Low temperature emission spectra of individual single-walled carbon nanotubes: multiplicity of subspecies within single-species nanotube ensembles.

Low-temperature photoluminescence (PL) studies of individual semiconducting single-walled carbon nanotubes reveal ultranarrow peaks (down to 0.25 meV linewidths) that exhibit blinking and spectral wandering. Multiple peaks appear within bands previously assigned to nanotubes of certain chiralities, indicating the existence of numerous subspecies within single-chirality specimens. The sharp PL features show two types of distinctly different shapes (symmetric versus asymmetric) and temperature dependences (weak versus strong), which we attribute to the presence of unintentionally doped nanotubes along with undoped species.

Percutaneous biopsy of periarterial soft tissue cuffs in the diagnosis of pancreatic carcinoma.

Pancreatic cancer may present on computed tomography (CT) as an isolated cuff of tumor surrounding the superior mesenteric artery (SMA) or celiac trunk, without an identifiable pancreatic mass. We reviewed our experience with imaging-guided biopsy of the soft tissue cuff in this patient group. A retrospective review of our interventional database identified 163 patients referred for biopsy of suspected pancreatic carcinoma. Of these, eight patients underwent biopsy of an isolated cuff of soft tissue encasing the SMA (n = 6) or celiac trunk (n = 2). None of these eight patients had an identifiable pancreatic mass. The mean width of tissue cuff biopsied was 1.3 cm (range, 0.9-2.0 cm). Nine imaging-guided biopsies were performed in eight patients. Five biopsies were performed with color Doppler ultrasound and four with CT fluoroscopy. There was a median of two needle passes per procedure (range, 1-4). In six cases, a diagnosis of pancreatic adenocarcinoma was made at the first biopsy session. In one patient, ultrasound-guided biopsy was negative, but subsequent CT-guided biopsy was positive. In one additional patient with chronic pancreatitis, biopsy revealed benign fibrous tissue. There were no procedure-related complications. In patients with suspected pancreatic cancer (but without a focal parenchymal mass), imaging-guided biopsy of isolated periarterial tissue cuffs of tumor is accurate and safe.

Transrectal ultrasound-guided biopsy of the prostate gland: value of 12 versus 6 cores.

We investigated the effect on prostate carcinoma detection of 12 versus 6 core biopsies at transrectal ultrasound (TRUS), when all biopsies are taken from the lateral peripheral zone. This was a prospective study of 202 consecutive men, ages 51 to 81 years, referred for TRUS-guided biopsy of the prostate gland. All patients had prostate serum antigen levels higher than 4.0 ng/mL and/or abnormal digital rectal examination. In each case three biopsies were taken from the peripheral zones of the right and left lobes of the prostate. Biopsies were taken at the apex, midway between the apex and the base, and at the base. A second set of biopsies was taken from the same regions and analyzed separately. In total, twelve biopsies were taken. Note was subsequently made of additional carcinoma diagnosis increase in Gleason grade, and new diagnoses of carcinoma in the opposite side of the gland diagnosed on the second set of biopsies alone. Seventy-eight of the 202 men (38.6%) had prostatic carcinoma diagnosed on TRUS-guided biopsy. Of these 78 patients, six were diagnosed with malignancy based on the second set of biopsies alone, a 2.9% increase in the 202 patients, representing an increased yield of 8.3% (95% confidence interval, 5.3-28.6%). In nine cases (12.5%; 95% confidence interval, 6.2-22.9%), the Gleason tumor grade was increased on the second set of sextant biopsies; in an additional nine cases, carcinoma was detected in the opposite side of the gland. There were two complications (1%). A 12- versus six-core biopsy strategy for TRUS-guided biopsy of the prostate gland improves detection and histologic grading of prostate carcinoma. The added benefit of additional biopsies was lower in this series than in some prior studies using extensive biopsy protocols.

The value of routine MR myelography at MRI of the lumbar spine.

PURPOSE: To determine whether a commercially available automated MR myelogram sequence improves the interpretation and diagnostic yield at MRI of the lumbar spine. MATERIAL AND METHODS: A total of 207 consecutive patients referred for MR examination of the lumbar spine for evaluation of low back pain or spinal radicular symptoms were included for study. All patients had initial imaging with sagittal T1-W and T2-W scans, followed by axial T2-W images. Subsequently an MR myelogram was acquired in each case in coronal, sagittal and oblique planes. MR myelogram images were evaluated initially and a diagnosis was established and recorded. Subsequently, a diagnosis was established by review of conventional images of the lumbar spine in sagittal and axial planes, in conjunction with the MR myelogram. The utility of the MR myelogram in establishing the diagnosis was graded on a 4-point scale, where grade 0 indicated that it contributed no additional information and grade 3 indicated that it was essential for diagnosis. Analysis of the additional value of myelography in patients with multilevel disease was made. RESULTS: Primary diagnoses were disc herniation in 69 cases (33%), degenerative disc disease in 51 cases (26%), spinal stenosis in 19 cases (9%), isolated lateral recess stenosis in 5 cases (2%), or other diagnoses, including facet degeneration in 48 cases (23%). Scans were normal in 15 cases (7%). MR myelography was graded as grade 0 in 151 cases (73%), grade 1 in 44 cases (21%) and grade 2 in 12 cases (6%). In no case was MR myelography essential for diagnosis (grade 3). In patients with multilevel disease (n=27), in 17 cases MR myelography was graded as grade 1 (63%) and in 8 cases grade 2 (30%). CONCLUSION: MR myelography when employed in routine practice was of limited value, assisting in establishing a diagnosis in a minority of cases (6%). The technique was of limited additional value in patients with multilevel pathology and to a lesser extent in patients with scoliosis, where it helped to establish the level most likely to account for pathology.

Transjugular liver biopsy: assessment of safety and efficacy of the Quick-Core biopsy needle.

BACKGROUND: We assessed the safety and efficacy of transjugular liver biopsy with the Quick-Core biopsy needle. METHODS: Fifty consecutive patients with liver failure and contraindications to percutaneous liver biopsy were referred for transjugular liver biopsy. Eighteen (36%) patients had thrombocytopenia (platelet range = 44-92/microL, mean = 66/microL), 31 (62%) patients had elevated prothrombin times (international normalized ratio range = 1.3-3, mean = 1.6), and 19 (38%) patients had ascites. The Cook Quick-Core biopsy needle was used. RESULTS: Average procedure time was 30 min. Transjugular access to the hepatic veins was successful in 49 of 50 cases. A transfemoral approach was used in one patient. Tissue specimens were satisfactory for histologic diagnosis in all cases. Established cirrhosis was present in 37 (74%) patients. The mean number of cores was 2.2 (range = 1-3). The mean number of portal triads per core was 10.4 (range = 6-20). There were no procedure-related complications. CONCLUSION: Transjugular liver biopsy with the Quick-Core biopsy needle is safe and effective in patients in whom the percutaneous route is contraindicated by coagulopathy or ascites.

Inhibition of Chk1-dependent G2 DNA damage checkpoint radiosensitizes p53 mutant human cells.

Cell cycle checkpoints are surveillance mechanisms that monitor and coordinate the order and fidelity of cell cycle events. When defects in the division program of a cell are detected, checkpoints prevent the pursuant cell cycle transition through regulation of the relevant cyclin-cdk complex(es). Checkpoints that respond to DNA damage have been described for the G1, S and G2 phases of the cell cycle. The p53 tumour suppressor is a key regulator of G1/S checkpoints, and can promote cell cycle delay or apoptosis in response to DNA damage. The importance of these events to cellular physiology is highlighted by the fact that tumours, in which p53 is frequently mutated, have widespread defects in the G1/S DNA damage checkpoints and a heightened level of genomic instability. G2/M DNA damage checkpoints have been defined by yeast genetics, though the genes in this response are conserved in mammals. We show here using biochemical and physiological assays that p53 is dispensable for a DNA damage checkpoint activated in the G2 phase of the cell cycle. Moreover, upregulation of p53 through serine 20 phosphorylation, does not occur in G2. Conversely, we show that the Chk1 protein kinase is essential for the human G2 DNA damage checkpoint. Importantly, inhibition of Chk1 in p53 deficient cells greatly sensitizes them to radiation, validating the hypothesis of targeting Chk1 in rational drug design and development for anti-cancer therapies.

Isolation and characterization of the Pin1/Ess1p homologue in Schizosaccharomyces pombe.

Pin1/Ess1p is a highly conserved WW domain-containing peptidyl-prolyl isomerase (PPIase); its WW domain binds specifically to phospho-Ser/Thr-Pro sequences and its catalytic domain isomerizes phospho-Ser/Thr-Pro bonds. Pin1 PPIase activity can alter protein conformation in a phosphorylation-dependent manner and/or promote protein dephosphorylation. Human Pin1 interacts with mitotic phosphoproteins, such as NIMA, Cdc25 and Wee1, and inhibits G(2)/M progression in Xenopus extracts. Depletion of Pin1 in HeLa cells and deletion of ESS1 in S. cerevisiae result in mitotic arrest. In addition, Pin1/Ess1p play roles in transcription in S. cerevisiae and in mammalian somatic cells. The S. pombe genome sequence has an open reading frame (ORF) that has 47% identity with Pin1. Expression of this ORF rescued the growth defect caused by ess1 deletion in S. cerevisiae, indicating that S. pombe Pin1p is a functional Pin1 homologue. Overexpression of pin1(+) in S. pombe caused slow growth and a G(1) delay. Deletion of pin1(+) (pin1 Delta) did not affect cell cycle progression or cell growth, but increased sensitivity to the cyclophilin inhibitor, cyclosporin A, suggesting that cyclophilin family PPIases have overlapping functions with the Pin1p PPIase. Deletion of pin1(+) did not affect the DNA replication checkpoint, but conferred a modest increase in UV sensitivity. Furthermore, the pin1 Delta allele caused a synthetic growth defect when combined with either cdc25-22 or wee1-50 but not the cdc24-1 temperature-sensitive mutant. The pin1 Delta strain showed increased sensitivity to the PP1/PP2A family phosphatase inhibitor, okadaic acid, suggesting that Pin1p plays a role in protein dephosphorylation as a result of its ability to increase the population of phospho-Ser/Thr-Pro peptide bonds in the trans conformation that is required for PP2A-mediated dephosphorylation. Our genetic data also suggest that Pin1p might function as a positive regulator of Cdc25p and Wee1p.

Impact of surgical and pathologic variables in rectal cancer: a United States community and cooperative group report.

PURPOSE: Substantial and successful effort has been focused on decreasing the risk of local failure after rectal cancer surgery through the use of adjuvant therapies. Our study examined data from studies conducted by United States cooperative groups to investigate the impact of surgical and pathologic variables in rectal cancer outcomes. PATIENTS AND METHODS: Surgical and pathologic reports from 673 patients with stage II/III rectal cancer enrolled onto three adjuvant clinical trials were reviewed for tumor and surgical variables. Additional information on individual institutions and operating surgeon was collected. Variables were tested for association with 5-year local recurrence and survival after adjustment for adjuvant treatments and other important prognostic factors. RESULTS: Five-year local recurrence and survival rates were 16% and 59%, respectively. Surgeons treating more than 10 study cases had lower local recurrence rates than those treating < or = 10 (11% v 17%, P =.02). Free radial margins also correlated with local recurrence (P =.01). Type of surgery, distal margins, and tumor radial spread were not significant. Tumor adherence to adjacent structures predicted local recurrence (35% v 14%, P <.001) and survival (30% v 63%, P <.001), regardless of en bloc resection. Although T and N classification predicted survival (P <.001), only N classification correlated with local recurrence. The number and percentage of positive nodes correlated with survival, but only the percentage independently predicted local recurrence. Several pathologic and surgical variables were reported suboptimally. CONCLUSION: Moderate variability in outcomes among surgeons was detected in this high-risk population. Efforts to improve surgical results will require changes in reporting practices to allow for more accurate assessment of the quality of surgery.

A homologue of the Rad18 postreplication repair gene is required for DNA damage responses throughout the fission yeast cell cycle.

Cells activate DNA repair pathways and cell cycle checkpoints when they suffer damage to their genome. They also activate tolerance pathways that facilitate survival. In Escherichia coli, a mechanism known as postreplication repair (PRR) is used to bypass lesions that would otherwise present a physical block to DNA polymerase. PRR has also been proposed to occur in eukaryotic cells, although the partitioning of DNA synthesis to a discrete S-phase would suggest that it is only operative within a defined period of the cell cycle. Eukaryotic PRR has been most extensively studied in the budding yeast Saccharomyces cerevisiae. Two important genes for components of this repair pathway are RAD6, which encodes an ubiquitin-conjugating enzyme, and RAD18, which encodes a RING-finger protein and forms a heterodimer with Rad6p. Rad18p can also bind to DNA. We report here the identification of the Schizosaccharomyces pombe homologue of RAD18, which we have denoted rhp18. rhp18 mutants are hypersensitive to DNA-damaging agents, but show this hypersensitivity throughout the cell cycle. rhp18 mutants are characterised by a longer than usual DNA damage checkpoint arrest that is required for their residual viability following irradiation. Genetic analyses show that rhp18 controls a unique DNA damage repair/tolerance pathway that extends beyond the requirement to tolerate damage during S-phase, suggesting a broader definition of the function of this eukaryotic PRR protein.