Ctp1 and the MRN-complex are required for endonucleolytic Rec12 removal with release of a single class of oligonucleotides in fission yeast

DNA double-strand breaks (DSBs) are formed during meiosis by the action of the topoisomerase-like Spo11/Rec12 protein, which remains covalently bound to the 5' ends of the broken DNA. Spo11/Rec12 removal is required for resection and initiation of strand invasion for DSB repair. It was previously shown that budding yeast Spo11, the homolog of fission yeast Rec12, is removed from DNA by endonucleolytic cleavage. The release of two Spo11 bound oligonucleotide classes, heterogeneous in length, led to the conjecture of asymmetric cleavage. In fission yeast, we found only one class of oligonucleotides bound to Rec12 ranging in length from 17 to 27 nucleotides. Ctp1, Rad50, and the nuclease activity of Rad32, the fission yeast homolog of Mre11, are required for endonucleolytic Rec12 removal. Further, we detected no Rec12 removal in a rad50S mutant. However, strains with additional loss of components localizing to the linear elements, Hop1 or Mek1, showed some Rec12 removal, a restoration depending on Ctp1 and Rad32 nuclease activity. But, deletion of hop1 or mek1 did not suppress the phenotypes of ctp1Delta and the nuclease dead mutant (rad32-D65N). We discuss what consequences for subsequent repair a single class of Rec12-oligonucleotides may have during meiotic recombination in fission yeast in comparison to two classes of Spo11-oligonucleotides in budding yeast. Furthermore, we hypothesize on the participation of Hop1 and Mek1 in Rec12 removal.

Right ventricular rupture after lateral thoracotomy for removal of rib-associated telangiectatic osteosarcoma in a dog

OBJECTIVE: To describe a case of a focal right ventricular rupture following removal of a rib-associated telangiectatic osteosarcoma (TOS) in a dog. CASE SUMMARY: A 2-year-old spayed female mixed-breed dog, weighing 20 kg, was presented in compensated hypovolemic shock due to active bleeding into the thoracic cavity. The dog was stabilized with appropriate fluid administration. Subsequent computed tomographic examination revealed a large mineralized mass originating from the body of a rib and displacing the heart. Two days after surgical removal of this mass, focal right ventricular rupture occurred and the dog died. The mass was later identified as a TOS. NEW OR UNIQUE INFORMATION PROVIDED: Although hemothorax secondary to TOS has been described previously, this report describes for the first time, spontaneous focal right ventricular rupture as a rare complication of thoracotomy and rib resection for the removal of a rib-associated, intrathoracic TOS.

Oesophageal and gastric endoscopic foreign body removal: complications and follow-up of 102 dogs

OBJECTIVES: To assess complication rate, risk factors for complications and outcome in dogs with oesophageal and gastric endoscopic foreign body (FB) removal. METHODS: Medical records of 102 dogs undergoing endoscopic removal of oesophageal and/or gastric FBs from March 2001 to November 2006 were retrospectively reviewed. All owners were contacted by telephone to provide follow-up information. RESULTS: West Highland white terriers, Yorkshire terriers and Bernese mountain dogs were over-represented compared to the hospital population. Endoscopy alone was successful in 92/102 dogs (90.2 per cent), whereas gastrotomy (but no oesophagotomy) was required in 10 dogs (9.8 per cent). Complications in 13/102 dogs (12.7 per cent) were perforation (8), oesophageal stricture (1), oesophageal diverticula (1), perioesophageal abscess (1), pneumothorax and pleural effusion (1) and respiratory arrest (1). Six dogs (all weighing <10 kg) had complications resulting in death or euthanasia. Bone FBs, bodyweight of less than 10 kg, and oesophageal or gastric FB in place for more than three days were significant risk factors for complications. Of the dogs available for follow-up (75/96), 92 per cent had no complications after discharge. CLINICAL SIGNIFICANCE: Endoscopic FB removal is associated with a low overall complication rate with bone FBs and bodyweight of less than 10 kg as significant risk factors.

A novel cryo-mechanical approach for the removal of blocked nonretrievable implant components

The removal of nonretrievable implant components represents a challenge in implant dentistry. The mechanical approach involves the risk of damaging the implant connection or the bone-to-implant interface. This case report describes a cryo-mechanical approach for the safe removal of a nonretrievable implant component. A patient had an implant surgically placed in a private practice. When the patient returned to the restorative dentist to make a definitive impression, the healing abutment could not be loosened. The patient was referred to the Division of Fixed Prosthodontics (University of Bern, Switzerland), where the stripped screw hole was enlarged with a special drill from a service kit of the implant provider. Although an extraction bolt was screwed into the opening and the torque ratchet was activated, the healing abutment would not loosen. A novel approach was attempted whereby the healing abutment was cooled with dry ice (CO2). The cooling effect seemingly caused shrinkage of the healing abutment and a reduction of the connection forces between the implant and the nonretrievable component. The approach of creating an access hole for the application of reverse torque via the extraction bolt in combination with the thermal effect led to the successful removal of the blocked component. Neither the implant connection nor the bone-to-implant interface was damaged. The combined cryo-mechanical procedure allowed the implant to be successfully restored.

Subordinate removal affects parental investment, but not offspring survival in a cooperative cichlid

Summary Subordinates in cooperative breeding systems may provide help to dominant pairs, who can benefit by either an increased total investment in their current brood or a reduced personal contribution to this investment. In the social cichlid Julidochromis ornatus, one large male subordinate generally spends 90% of his time in close proximity to the breeding shelter, whereas the dominants only spend 50% of their time close to the shelter. We experimentally removed the large subordinate for 30 days (approximating one breeding cycle) to study the investment strategies of dominants and the effects on offspring survival, while accounting for subordinate immigration. Experimental groups were compared with control groups, from which subordinates were also caught but not removed. On day one following removal, we tested whether dominants overcompensated, fully compensated or undercompensated for absence of the subordinate on several parental behaviours. Moreover, we tested whether the pairs' potential compensatory behaviour remained high seven days following large subordinate removal. One day following removal, dominants increased their time spent in the territory and their frequency of breeding shelter visits and defence, compared with the pre-removal phase and control groups. The dominant pair overcompensated for the loss of subordinate help in their breeding shelter visits, fully compensated in defence and undercompensated their time spent in the territory. Seven days after large subordinate removal, behavioural differences between treatments had disappeared. However, when distinguishing between groups with or without a new immigrant subordinate, dominant pairs only diminished investment in the presence of an immigrant, suggesting a compensatory role of the large subordinate. Finally, survival of juvenile group members was not affected by the treatment. Our experiments indicate that the presence of a large subordinate does not increase the dominant pairs' current reproductive success, but instead allows them to reduce their personal contribution to investment in the current brood. In addition, we illustrate that dominants may show strikingly different compensatory responses depending on the type of behaviour and emphasize the importance of immigrant subordinates to relieve dominants from costly compensatory responses in cooperative breeding systems.

Removal of Limited Nodal Disease in Patients Undergoing Radical Prostatectomy: Long-Term Results Confirm a Chance for Cure

Abstract PURPOSE: In 2003 we reported on the outcomes of 88 patients with node positive disease who underwent radical prostatectomy and pelvic lymph node dissection (median 21 nodes) between 1989 and 1999. Patients with limited nodal disease appeared to have a good chance of long-term survival, even without immediate adjuvant therapy (androgen deprivation therapy and/or radiotherapy). In this study we update the followup in these patients and verify the reported projected probability of survival. MATERIALS AND METHODS: The projected 10-year cancer specific survival probability after the initially reported followup of 3.2 years was 60% for these patients with node positive disease. The outcome has been updated after a median followup of 15.6 years. RESULTS: Of the 39 patients with 1 positive node 7 (18%) remained biochemically relapse-free, 11 (28%) showed biochemical relapse only and 21 (54%) experienced clinical progression. Of these 39 patients 22 (57%) never required deferred androgen deprivation therapy and 12 (31%) died of prostate cancer. All patients with 2 (20) or more than 2 (29) positive nodes experienced biochemical relapse and only 5 (10%) of these 49 experienced no clinical progression. Of these 49 patients 39 (80%) received deferred androgen deprivation therapy. CONCLUSIONS: Biochemical relapse is likely in patients with limited nodal disease after radical prostatectomy and pelvic lymph node dissection, but for 47% of patients this does not imply death from prostate cancer. Patients with 1 positive node have a good (75%) 10-year cancer specific survival probability and a 20% chance of remaining biochemical relapse-free even without immediate adjuvant therapy.

Catheter removal versus retention in the management of catheter-associated enterococcal bloodstream infections

BACKGROUND Enterococci are an important cause of central venous catheter (CVC)-associated bloodstream infections (CA-BSI). It is unclear whether CVC removal is necessary to successfully manage enterococcal CA-BSI. METHODS A 12-month retrospective cohort study of adults with enterococcal CA-BSI was conducted at a tertiary care hospital; clinical, microbiological and outcome data were collected. RESULTS A total of 111 patients had an enterococcal CA-BSI. The median age was 58.2 years (range 21 to 94 years). There were 45 (40.5%) infections caused by Entercoccus faecalis (among which 10 [22%] were vancomycin resistant), 61 (55%) by Enterococcus faecium (57 [93%] vancomycin resistant) and five (4.5%) by other Enterococcus species. Patients were treated with linezolid (n=51 [46%]), vancomycin (n=37 [33%]), daptomycin (n=11 [10%]), ampicillin (n=2 [2%]) or quinupristin/dalfopristin (n=2 [2%]); seven (n=6%) patients did not receive adequate enterococcal treatment. Additionally, 24 (22%) patients received adjunctive gentamicin treatment. The CVC was retained in 29 (26.1%) patients. Patients with removed CVCs showed lower rates of in-hospital mortality (15 [18.3%] versus 11 [37.9]; P=0.03), but similar rates of recurrent bacteremia (nine [11.0%] versus two (7.0%); P=0.7) and a similar post-BSI length of hospital stay (median days [range]) (11.1 [1.7 to 63.1 days] versus 9.3 [1.9 to 31.8 days]; P=0.3). Catheter retention was an independent predictor of mortality (OR 3.34 [95% CI 1.21 to 9.26]). CONCLUSIONS To the authors' knowledge, the present article describes the largest enterococcal CA-BSI series to date. Mortality was increased among patients who had their catheter retained. Additional prospective studies are necessary to determine the optimal management of enterococcal CA-BSI.

Antibiotic prophylaxis for urinary tract infections after removal of urinary catheter: meta-analysis

Abstract Objective To determine whether antibiotic prophylaxis at the time of removal of a urinary catheter reduces the risk of subsequent symptomatic urinary tract infection. Design Systematic review and meta-analysis of studies published before November 2012 identified through PubMed, Embase, Scopus, and the Cochrane Library; conference abstracts for 2006-12 were also reviewed. Inclusion criteria Studies were included if they examined antibiotic prophylaxis administered to prevent symptomatic urinary tract infection after removal of a short term (≤14 days) urinary catheter. Results Seven controlled studies had symptomatic urinary tract infection after catheter removal as an endpoint; six were randomized controlled trials (five published; one in abstract form) and one was a non-randomized controlled intervention study. Five of these seven studies were in surgical patients. Studies were heterogeneous in the type and duration of antimicrobial prophylaxis and the period of observation. Overall, antibiotic prophylaxis was associated with benefit to the patient, with an absolute reduction in risk of urinary tract infection of 5.8% between intervention and control groups. The risk ratio was 0.45 (95% confidence interval 0.28 to 0.72). The number needed to treat to prevent one urinary tract infection was 17 (12 to 30). Conclusions Patients admitted to hospital who undergo short term urinary catheterization might benefit from antimicrobial prophylaxis when the catheter is removed as they experience fewer subsequent urinary tract infections. Potential disadvantages of more widespread antimicrobial prophylaxis (side effects and cost of antibiotics, development of antimicrobial resistance) might be mitigated by the identification of which patients are most likely to benefit from this approach.

Upper ocean vertical supply: A neglected primary factor controlling the distribution of neodymium concentrations of open ocean surface waters?

Neodymium (Nd) isotopes are an important geochemical tool to trace the present and past water mass mixing as well as continental inputs. The distribution of Nd concentrations in open ocean surface waters (0�100 m) is generally assumed to be controlled by lateral mixing of Nd from coastal surface currents and by removal through reversible particle scavenging. However, using 228Ra activity as an indicator of coastal water mass influence, surface water Nd concentration data available on key oceanic transects as a whole do not support the above scenario. From a global compilation of available data, we find that more stratified regions are generally associated with low surface Nd concentrations. This implies that upper ocean vertical supply may be an as yet neglected primary factor in determining the basin-scale variations of surface water Nd concentrations. Similar to the mechanism of nutrients supply, it is likely that stratification inhibits vertical supply of Nd from the subsurface thermocline waters and thus the magnitude of Nd flux to the surface layer. Consistently, the estimated required input flux of Nd to the surface layer to maintain the observed concentrations could be nearly two orders of magnitudes larger than riverine/dust flux, and also larger than the model-based estimation on shelf-derived coastal flux. In addition, preliminary results from modeling experiments reveal that the input from shallow boundary sources, riverine input, and release from dust are actually not the primary factors controlling Nd concentrations most notably in the Pacific and Southern Ocean surface waters.

Impact of dams, dam removal and dam-related river engineering structures on sediment connectivity and channel morphology of the Fugnitz and the Kaja Rivers

In terms of changing flow and sediment regimes of rivers, dams are often regarded as the most dominant form of human impact on fluvial systems. Dams can decrease the flux of water and sediments leading to channel changes such as upstream aggradation and downstream degradation. The opposite effects occur when dams are removed. Channel degradation often requires further intervention in terms of river bed and bank protection works. The situation evolves more complex in river systems that are impacted by a series of dams due to feedback processes between the different system compartments. A number of studies have recently investigated geomorphic systems using connectivity approaches to improve the understanding of geomorphic system response to change. This paper presents a case study investigating the impact of dam construction, dam removal and dam-related river bed and bank protection measures on the sediment connectivity and channel morphology of the Fugnitz and the Kaja Rivers using a combination of DEM analyses, field surveys and landscape evolution modelling. For both river systems the results revealed low sediment connectivity accompanied by a fine river bed sediment facies in river sections upstream of active dams and of removed dams with protection measures. Contrarily, high sediment connectivity which was accompanied by a coarse river bed sediment facies was observed in river sections either located downstream of active dams or of removed dams with upstream protection. In terms of channel changes, significant channel degradation was examined at locations downstream of active dams and of removed dams. Channel bed and bank protection measures prevent erosion and channel slope recovery after dam removal. Landscape evolution modeling revealed a complex geomorphic response to dam construction and dam removal as sediment output rates and therefore geomorphic processes have been shown to act in a non-linear manner. These insights are deemed to have major implications for river management and conservation, as quality and state of riverine habitats are determined by channel morphology and river bed sediment composition.

Ethnic differences in do-not-resuscitate orders after intracerebral hemorrhage.

OBJECTIVE: To explore ethnic differences in do-not-resuscitate orders after intracerebral hemorrhage. DESIGN: Population-based surveillance. SETTING: Corpus Christi, Texas. PATIENTS: All cases of intracerebral hemorrhage in the community of Corpus Christi, TX were ascertained as part of the Brain Attack Surveillance in Corpus Christi (BASIC) project. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were reviewed for do-not-resuscitate orders. Unadjusted and multivariable logistic regression were used to test for associations between ethnicity and do-not-resuscitate orders, both overall ("any do-not-resuscitate") and within 24 hrs of presentation ("early do-not-resuscitate"), adjusted for age, gender, Glasgow Coma Scale, intracerebral hemorrhage volume, intraventricular hemorrhage, infratentorial hemorrhage, modified Charlson Index, and admission from a nursing home. A total of 270 cases of intracerebral hemorrhage from 2000-2003 were analyzed. Mexican-Americans were younger and had a higher Glasgow Coma Scale than non-Hispanic whites. Mexican-Americans were half as likely as non-Hispanic whites to have early do-not-resuscitate orders in unadjusted analysis (odds ratio 0.45, 95% confidence interval 0.27, 0.75), although this association was not significant when adjusted for age (odds ratio 0.61, 95% confidence interval 0.35, 1.06) and in the fully adjusted model (odds ratio 0.75, 95% confidence interval 0.39, 1.46). Mexican-Americans were less likely than non-Hispanic whites to have do-not-resuscitate orders written at any time point (odds ratio 0.37, 95% confidence interval 0.23, 0.61). Adjustment for age alone attenuated this relationship although it retained significance (odds ratio 0.49, 95% confidence interval 0.29, 0.82). In the fully adjusted model, Mexican-Americans were less likely than non-Hispanic whites to use do-not-resuscitate orders at any time point, although the 95% confidence interval included one (odds ratio 0.52, 95% confidence interval 0.27, 1.00). CONCLUSIONS: Mexican-Americans were less likely than non-Hispanic whites to have do-not-resuscitate orders after intracerebral hemorrhage although the association was attenuated after adjustment for age and other confounders. The persistent trend toward less frequent use of do-not-resuscitate orders in Mexican-Americans suggests that further study is warranted.

Biomass and Stored Carbohydrate Compensation after Above-Ground Biomass Removal in a Perennial Herb: Does Environmental Productivity Play a Role?

Many plant species are able to tolerate severe disturbance leading to removal of a substantial portion of the body by resprouting from intact or fragmented organs. Resprouting enables plants to compensate for biomass loss and complete their life cycles. The degree of disturbance tolerance, and hence the ecological advantage of damage tolerance (in contrast to alternative strategies), has been reported to be affected by environmental productivity. In our study, we examined the influence of soil nutrients (as an indicator of environmental productivity) on biomass and stored carbohydrate compensation after removal of aboveground parts in the perennial resprouter Plantago lanceolata. Specifically, we tested and compared the effects of nutrient availability on biomass and carbon storage in damaged and undamaged individuals. Damaged plants of P. lanceolata compensated neither in terms of biomass nor overall carbon storage. However, whereas in the nutrient-poor environment, root total non-structural carbohydrate concentrations (TNC) were similar for damaged and undamaged plants, in the nutrient-rich environment, damaged plants had remarkably higher TNC than undamaged plants. Based on TNC allocation patterns, we conclude that tolerance to disturbance is promoted in more productive environments, where higher photosynthetic efficiency allows for successful replenishment of carbohydrates. Although plants under nutrient-rich conditions did not compensate in terms of biomass or seed production, they entered winter with higher content of carbohydrates, which might result in better performance in the next growing season. This otherwise overlooked compensation mechanism might be responsible for inconsistent results reported from other studies.