Reducing surgical site infection following caesarean section.

AIM: To set up a surgical site infection (SSI) benchmark rate for caesarean sections and improve infection rates by monitoring and implementing compliance with the guidelines produced by the National Institute for Health and Clinical Excellence (NICE). METHOD: A total of 2382 patients who had undergone caesarean section at Maidstone and Tunbridge Wells NHS Trust were monitored at two obstetric sites over a two-year period. A proactive infection surveillance system was used during the patients' hospital stay. Community midwives collected and returned post-discharge data on wound status. Patients were asked to return post-operative questionnaires 30 days after surgery, providing details of any wound problems. Compliance with NICE guidance on reducing SSIs was measured at both sites and changes were implemented accordingly. RESULTS: Infection rates before compliance with NICE guidance from July 2008 to June 2009 ranged from 5.7% to 9.0%. After introducing the guidelines, rates of SSI at site A and site B were reduced by 3.3% and 3.8% respectively. Rates of SSI at site A were reduced further to 1.3% on introduction of the hydrofiber and hydrocolloid dressing. CONCLUSION: Results suggest that the hydrofiber and hydrocolloid combination dressing assists in the reduction of SSI rates following caesarean section when used in combination with the NICE guidance.

A human condensin complex containing hCAP-C-hCAP-E and CNAP1, a homolog of Xenopus XCAP-D2, colocalizes with phosphorylated histone H3 during the early stage of mitotic chromosome condensation.

Structural maintenance of chromosomes (SMC) family proteins play critical roles in structural changes of chromosomes. Previously, we identified two human SMC family proteins, hCAP-C and hCAP-E, which form a heterodimeric complex (hCAP-C-hCAP-E) in the cell. Based on the sequence conservation and mitotic chromosome localization, hCAP-C-hCAP-E was determined to be the human ortholog of the Xenopus SMC complex, XCAP-C-XCAP-E. XCAP-C-XCAP-E is a component of the multiprotein complex termed condensin, required for mitotic chromosome condensation in vitro. However, presence of such a complex has not been demonstrated in mammalian cells. Coimmunoprecipitation of the endogenous hCAP-C-hCAP-E complex from HeLa extracts identified a 155-kDa protein interacting with hCAP-C-hCAP-E, termed condensation-related SMC-associated protein 1 (CNAP1). CNAP1 associates with mitotic chromosomes and is homologous to Xenopus condensin component XCAP-D2, indicating the presence of a condensin complex in human cells. Chromosome association of human condensin is mitosis specific, and the majority of condensin dissociates from chromosomes and is sequestered in the cytoplasm throughout interphase. However, a subpopulation of the complex was found to remain on chromosomes as foci in the interphase nucleus. During late G(2)/early prophase, the larger nuclear condensin foci colocalize with phosphorylated histone H3 clusters on partially condensed regions of chromosomes. These results suggest that mitosis-specific function of human condensin may be regulated by cell cycle-specific subcellular localization of the complex, and the nuclear condensin that associates with interphase chromosomes is involved in the reinitiation of mitotic chromosome condensation in conjunction with phosphorylation of histone H3.

PO-51 - Expression of proteins of the tissue factor thrombin pathway is upregulated in the stroma and epithelium of colorectal cancer.

INTRODUCTION: Colorectal cancer expression of Tissue Factor (TF), PAR1 and PAR2 is associated with a poor prognosis. Their stromal, rather than epithelial, expression has prognostic significance in other cancers, this has not been explored in colorectal cancer. AIM: We aimed to determine the expression patterns of Tissue Factor (TF), PAR1 and PAR2 and thrombin in colorectal cancer and normal tissue. MATERIALS AND METHODS: Cancer and distant normal tissue were sampled from 37 patients. Expression of TF, Thrombin, PAR1 and PAR2 were determined by immunohistochemistry. Two observers scored expression level (0-3) in individual cells. Percentage of cells having each level of expression was determined and an H-score calculated which are given with 95% CI. RESULTS: Normal epithelium did not express TF, but it was expressed by cancer epithelium (36.5 (95% CI 17.6 - 55.4) p<0.001). Thrombin expression was increased in cancer vs normal epithelium (126.2 (95% CI 110.6 - 141.7) vs 101.6 (95% CI 92.5-110.8) p=0.01) as was PAR2 (172.4 (95% CI 152.9-191.8) vs 123.4 (95% CI 107.8-139.0) p<0.001). The increase in cancer epithelium PAR1 expression compared to normal (105.4 (95%CI 84.3-126.5) vs 89.0 (95% CI 80.4-97.6)) was not significant. Normal stroma did not express TF or thrombin however both were expressed by cancer stroma (TF 46.3 (95% CI 24.6-68.0) p<0.001, thrombin 11.4 (95% CI 6.2-16.7) p<0.001). PAR1 and PAR2 were both expressed in normal stroma but demonstrated increased expression in cancer stroma (cancer vs normal; PAR 1: 130.7 (95% CI 112.2-149.2) vs 19.5 (95% CI 11.24-27.7) p<0.001; PAR2: 21.5 (95% CI 12.9-30.1) vs 2.21 (95% CI 0.49-3.92) p<0.001). CONCLUSIONS: Upregulated expression of tissue thrombin pathway proteins is seen in colorectal cancer in both epithelial and stromal cells. Procoagulant tumour cells and tumour microenvironment may provide a novel therapeutic target for treatment in colorecal cancer.

Circulating cardiac troponin-T in patients before and after renal transplantation.

BACKGROUND: The diagnostic and prognostic use of cardiac troponin T (cTnT) in patients with renal failure has been questioned. Raised serum concentrations of cTnT, with no apparent signs of cardiac damage using conventional methods of detection, have been reported. We aimed to relate circulating concentrations of cTnT to improved renal function following renal transplantation over a one-year period. METHOD: Plasma cTnT was analysed from patients with end stage renal disease before and after transplantation and subsequently at 1, 3, 6 and 12 months. Eight patients had diabetes, 14 had hyperlipidaemia, 8 were smokers and 4 were ex-smokers; all were hypersensitive. RESULTS: At the time of transplantation, 3 of the 32 patients (9.4%) had plasma cTnT concentrations above 0.1 microg/l. In addition to these three patients, five others showed raised cTnT over the one-year period. CONCLUSIONS: The overall trend in circulating cTnT concentrations did not seem to be affected by improved renal function. However, all of the patients that had raised cTnT concentrations at any stage of the one-year period had explainable pathologies or were exposed to multiple cardiac risk factors.

Cardiac structural and functional abnormalities in end stage renal disease patients with elevated cardiac troponin T.

OBJECTIVES: To identify in a prospective observational study the cardiac structural and functional abnormalities and mortality in patients with end stage renal disease (ESRD) with a raised cardiac troponin T (cTnT) concentration. METHODS: 126 renal transplant candidates were studied over a two year period. Clinical, biochemical, echocardiographic, coronary angiographic, and dobutamine stress echocardiographic (DSE) data were examined in comparison with cTnT concentrations dichotomised at cut off concentrations of < 0.04 microg/l and < 0.10 microg/l. RESULTS: Left ventricular (LV) size and filling pressure were significantly raised and LV systolic and diastolic function parameters significantly impaired in patients with raised cTnT, irrespective of the cut off concentration. The proportions of patients with diabetes and on dialysis were higher in both groups with raised cTnT. With a cut off cTnT concentration of 0.04 microg/l but not 0.10 microg/l, significantly more patients had severe coronary artery disease and a positive DSE result. The total ischaemic burden during DSE was similar in cTnT positive and negative patients, irrespective of the cut off concentration used. LV end systolic diameter index and E:Ea ratio were independent predictors of cTnT rises > or = 0.04 microg/l and > or = 0.10 microg/l, respectively. Diabetes was independently associated with cTnT at both cut off concentrations. Mortality was higher in all patients with raised cTnT. CONCLUSIONS: Patients with ESRD with raised cTnT concentrations have increased mortality. Raised concentrations are strongly associated with diabetes, LV dilatation, and impaired LV systolic and diastolic function, but not with severe coronary artery disease.

A potential role for human cohesin in mitotic spindle aster assembly.

The cohesin multiprotein complex containing SMC1, SMC3, Scc3 (SA), and Scc1 (Rad21) is required for sister chromatid cohesion in eukaryotes. Although metazoan cohesin associates with chromosomes and was shown to function in the establishment of sister chromatid cohesion during interphase, the majority of cohesin was found to be off chromosomes and reside in the cytoplasm in metaphase. Despite its dissociation from chromosomes, however, microinjection of an antibody against human SMC1 led to disorganization of the metaphase plate and cell cycle arrest, indicating that human cohesin still plays an important role in metaphase. To address the mitotic function of human cohesin, the subcellular localization of cohesin components was reexamined in human cells. Interestingly, we found that cohesin localizes to the spindle poles during mitosis and interacts with NuMA, a spindle pole-associated factor required for mitotic spindle organization. The interaction with NuMA persists during interphase. Similar to NuMA, a significant amount of cohesin was found to associate with the nuclear matrix. Furthermore, in the absence of cohesin, mitotic spindle asters failed to form in vitro. Our results raise the intriguing possibility that in addition to its well demonstrated function in sister chromatid cohesion, cohesin may be involved in spindle assembly during mitosis.

Identification of two distinct human SMC protein complexes involved in mitotic chromosome dynamics.

The structural maintenance of chromosomes (SMC) family member proteins previously were shown to play a critical role in mitotic chromosome condensation and segregation in yeast and Xenopus. Other family members were demonstrated to be required for DNA repair in yeast and mammals. Although several different SMC proteins were identified in different organisms, little is known about the SMC proteins in humans. Here, we report the identification of four human SMC proteins that form two distinct heterodimeric complexes in the cell, the human chromosome-associated protein (hCAP)-C and hCAP-E protein complex (hCAP-C/hCAP-E), and the human SMC1 (hSMC1) and hSMC3 protein complex (hSMC1/hSMC3). The hCAP-C/hCAP-E complex is the human ortholog of the Xenopus chromosome-associated protein (XCAP)-C/XCAP-E complex required for mitotic chromosome condensation. We found that a second complex, hSMC1/hSMC3, is required for metaphase progression in mitotic cells. Punctate vs. diffuse distribution patterns of the hCAP-C/hCAP-E and hSMC1/hSMC3 complexes in the interphase nucleus indicate independent behaviors of the two complexes during the cell cycle. These results suggest that two distinct classes of SMC protein complexes are involved in different aspects of mitotic chromosome organization in human cells.

Specification of kinetochore-forming chromatin by the histone H3 variant CENP-A.

The mechanisms that specify precisely where mammalian kinetochores form within arrays of centromeric heterochromatin remain largely unknown. Localization of CENP-A exclusively beneath kinetochore plates suggests that this distinctive histone might direct kinetochore formation by altering the structure of heterochromatin within a sub-region of the centromere. To test this hypothesis, we experimentally mistargeted CENP-A to non-centromeric regions of chromatin and determined whether other centromere-kinetochore components were recruited. CENP-A-containing non-centromeric chromatin assembles a subset of centromere-kinetochore components, including CENP-C, hSMC1, and HZwint-1 by a mechanism that requires the unique CENP-A N-terminal tail. The sequence-specific DNA-binding protein CENP-B and the microtubule-associated proteins CENP-E and HZW10 were not recruited, and neocentromeric activity was not detected. Experimental mistargeting of CENP-A to inactive centromeres or to acentric double-minute chromosomes was also not sufficient to assemble complete kinetochore activity. The recruitment of centromere-kinetochore proteins to chromatin appears to be a unique function of CENP-A, as the mistargeting of other components was not sufficient for assembly of the same complex. Our results indicate at least two distinct steps in kinetochore assembly: (1) precise targeting of CENP-A, which is sufficient to assemble components of a centromere-prekinetochore scaffold; and (2) targeting of kinetochore microtubule-associated proteins by an additional mechanism present only at active centromeres.