RNA-directed DNA methylation mutants reduce histone methylation at the paramutated maize booster1 enhancer.

Paramutation is the transfer of mitotically and meiotically heritable silencing information between two alleles. With paramutation at the maize (Zea mays) booster1 (b1) locus, the low-expressed B' epiallele heritably changes the high-expressed B-I epiallele into B' with 100% frequency. This requires specific tandem repeats and multiple components of the RNA-directed DNA methylation pathway, including the RNA-dependent RNA polymerase (encoded by mediator of paramutation1, mop1), the second-largest subunit of RNA polymerase IV and V (NRP(D/E)2a, encoded by mop2), and the largest subunit of RNA Polymerase IV (NRPD1, encoded by mop3). Mutations in mop genes prevent paramutation and release silencing at the B' epiallele. In this study, we investigated the effect of mutations in mop1, mop2, and mop3 on chromatin structure and DNA methylation at the B' epiallele, and especially the regulatory hepta-repeat 100 kb upstream of the b1 gene. Mutations in mop1 and mop3 resulted in decreased repressive histone modifications H3K9me2 and H3K27me2 at the hepta-repeat. Associated with this decrease were partial activation of the hepta-repeat enhancer function, formation of a multi-loop structure, and elevated b1 expression. In mop2 mutants, which do not show elevated b1 expression, H3K9me2, H3K27me2 and a single-loop structure like in wild-type B' were retained. Surprisingly, high CG and CHG methylation levels at the B' hepta-repeat remained in all three mutants, and CHH methylation was low in both wild type and mutants. Our results raise the possibility of MOP factors mediating RNA-directed histone methylation rather than RNA-directed DNA methylation at the b1 locus.

Novel use of the Perceval sutureless bioprosthesis for pulmonary valve replacement in high-risk endocarditis patients: A case series.

We present the first known cases of successful implantation of the Perceval sutureless bioprosthetic valve in the pulmonary position in two high-risk endocarditis patients.

Children's toys no longer: a porcine model study of the lethality of modern air rifles.

AIMS: We observed modern spring-loaded air rifles reaching velocities similar to small-bore rifles, raising concerns about their potential lethality. After encountering two life-threatening thoracic injuries in our practice, we conducted a study to assess the injuries that a commonly available air rifle could cause in a porcine cadaver model. METHODS: We conducted shooting experiments from 5 and 10 metres away using a .22 calibre spring-loaded airgun, firing five shots into the anterolateral chest on the left side at both distances. Additionally, we repeated the experiment with ten shots into 10% ballistics gel behind an explanted chest wall to evaluate chest wall penetration reliability. RESULTS: Out of the ten combined shots, six resulted in lethal or potentially lethal injuries, including multiple cardiac injuries. Moreover, we observed chest wall penetration in 9 out of 10 shots, with an average penetration depth of 106mm. Non-life-threatening injuries appeared to be influenced by shot location rather than an inability to penetrate the chest wall. CONCLUSION: Our study raises significant concerns about the potential lethality of unrestricted air rifles in New Zealand. With muzzle velocities comparable to small-bore rifles, these firearms should be reconsidered in terms of regulation and possibly restricted to gun license holders.

Is the New Zealand Early Warning Score useful following cardiac surgery?

AIMS: The rate of medical emergency team (MET) calling among post-cardiac surgery patients is unknown. We set out to determine what the call frequency would be if MET activation occurred in every instance that the early warning score (EWS) breached our local threshold, what the outcome was for these patients and what the calling rate might be if the proposed New Zealand EWS (NZEWS) system was implemented with 100% adherence. METHODS: The clinical records of 400 consecutive post-cardiac surgery patients were examined. The number of times a patient's EWS reached the threshold which mandated a call to the MET was determined, as was the actual rate of calling, the occurrence of inpatient death and re-admission to the intensive care unit (ICU). The rate of calling was then determined using the NZEWS, and with a routine modification to the heart rate score. RESULTS: There were 73 occasions (MET events) where the EWS reached the MET calling threshold. The MET was only called twice. There were no inpatient deaths and 12 ICU re-admissions in the study cohort. Nine ICU re-admissions were preceded by a MET event, two by cardiac arrest and one had neither. Re-scoring with NZEWS yielded 53 events. Eight of the 12 ICU admissions were preceded by a NZEWS event. CONCLUSIONS: The rate of MET triggering EWS in patients post-cardiac surgery is high at 182/1,000 admissions. Using NZEWS could reduce the MET calling rate without significant risk to patient safety.

The costs of elective and emergency abdominal aortic aneurysm repair: a comparative single centre study.

AIM: Population-based screening for abdominal aortic aneurysms (AAA) is being considered in New Zealand. However, there is a lack of data to support its cost effectiveness in this country. The aim of this study was to compare the hospital costs of AAA repair in emergency and elective cases over a 3-year period in a single centre in New Zealand. METHODS: A retrospective observational analysis of consecutive patients undergoing elective and emergency AAA repair during the study period (January 2009 to December 2011) was performed. RESULTS: A total of 169 AAA repairs were performed during the study period, of which 114 (67%) were open repairs. Sixty-four of these were open elective AAA repairs, 40 were open ruptured repairs, and 10 were open symptomatic repairs. The mean inpatient cost was $38,804 for open ruptured AAA repair and $28,019 for open elective repair, a difference of $10,785 (95%CI: $249 to $21,321; p=.045). The costs of blood products and laboratory investigations were significantly greater in the ruptured group than the elective. There was no significant difference in length of hospital admission between the groups. CONCLUSIONS: This study demonstrates that ruptured AAA repairs are more expensive than elective AAA repairs, despite no difference in length of hospital stay. The estimated inpatient costs documented in this study for each type of repair can be used for cost-effectiveness analysis in New Zealand. A screening program that reduces the incidence of surgery for ruptured AAA could decrease the average inpatient cost of AAA repairs.