University of Nebraska Omaha

About: University of Nebraska Omaha is a education organization based out in Omaha, Nebraska, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 4526 authors who have published 8905 publications receiving 213914 citations. The organization is also known as: UNO & University of Omaha.

Nuclease Modulates Biofilm Formation in Community-Associated Methicillin-Resistant Staphylococcus aureus

Abstract: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging contributor to biofilm-related infections We recently reported that strains lacking sigma factor B (sigB) in the USA300 lineage of CA-MRSA are unable to develop a biofilm Interestingly, when spent media from a USA300 sigB mutant was incubated with other S aureus strains, biofilm formation was inhibited Following fractionation and mass spectrometry analysis, the major anti-biofilm factor identified in the spent media was secreted thermonuclease (Nuc) Considering reports that extracellular DNA (eDNA) is an important component of the biofilm matrix, we investigated the regulation and role of Nuc in USA300 The expression of the nuc gene was increased in a sigB mutant, repressed by glucose supplementation, and was unaffected by the agr quorum-sensing system A FRET assay for Nuc activity was developed and confirmed the regulatory results A USA300 nuc mutant was constructed and displayed an enhanced biofilm-forming capacity, and the nuc mutant also accumulated more high molecular weight eDNA than the WT and regulatory mutant strains Inactivation of nuc in the USA300 sigB mutant background partially repaired the sigB biofilm-negative phenotype, suggesting that nuc expression contributes to the inability of the mutant to form biofilm To test the generality of the nuc mutant biofilm phenotypes, the mutation was introduced into other S aureus genetic backgrounds and similar increases in biofilm formation were observed Finally, using multiple S aureus strains and regulatory mutants, an inverse correlation between Nuc activity and biofilm formation was demonstrated Altogether, our findings confirm the important role for eDNA in the S aureus biofilm matrix and indicates Nuc is a regulator of biofilm formation

Excessive Tibial Rotation During High-Demand Activities Is Not Restored by Anterior Cruciate Ligament Reconstruction

Abstract: Purpose: Recent in vitro research has suggested that anterior cruciate ligament (ACL) reconstruction does not restore control of tibial rotation. The purpose of this study was to explore these findings in vivo and investigate rotational knee stability during landing and subsequent pivoting. Such an activity places higher demands on the knee, almost similar to those found during high-level sports. Type of Study: Case control series study. Methods: We assessed 11 patients who had undergone ACL reconstruction with the same arthroscopic technique using a bone–patellar tendon–bone graft, 11 ACL-deficient subjects who had sustained the injury more than 1 year prior to testing, and 11 matched controls. Kinematic data were collected (50 Hz) with a 6-camera optoelectronic system while the subjects performed the following task: they jumped off a 40-cm platform and landed on the ground. After foot contact, the subjects were instructed to pivot at 90° and walk away from the platform. The evaluation period was identified from initial foot contact with the ground with both legs, included the pivoting of the ipsilateral leg, and was completed on touchdown of the contralateral leg. Results: Significant differences were found between the reconstructed leg of the ACL group and the healthy control, and between the deficient leg of the ACL-deficient group and the healthy control. We also found no significant differences between the deficient leg of the ACL-deficient group and the reconstructed leg of the ACL reconstructed group. Conclusions: It was concluded that, under high-stress activities, ACL reconstruction may not restore tibial rotation to the previous physiological level, even though anterior tibial translation is restored. Future research on ACL reconstruction should focus on the development of new surgical procedures and/or grafts to address this problem. Level of Evidence: Level III.

Procedural results and acute complications in stenting native and recurrent coarctation of the aorta in patients over 4 years of age: a multi-institutional study.

Abstract: Background: We report a multi-institutional experience with intravascular stenting (IS) for treatment of coarctation of the aorta. Methods and Results: Data was collected retrospectively by review of medical records from 17 institutions. The data was broken down to prior to 2002 and after 2002 for further analysis. A total of 565 procedures were performed with a median age of 15 years (mean = 18.1 years). Successful reduction in the post stent gradient ( 0.8 was achieved in 97.9% of procedures. There was significant improvement (P < 0.01) in pre versus post stent coarctation dimensions (7.4 mm ± 3.0 mm vs. 14.3 ± 3.2mm), systolic gradient (31.6 mm Hg ± 16.0 mm Hg vs. 2.7 mm Hg ± 4.2 mm Hg) and ratio of the coarctation segment to the DAo (0.43 ± 0.17 vs. 0.85 ± 0.15). Acute complications were encountered in 81/565 (14.3%) procedures. There were two procedure related deaths. Aortic wall complications included: aneurysm formation (n = 6), intimal tears (n = 8), and dissections (n = 9). The risk of aortic dissection increased significantly in patients over the age of 40 years. Technical complications included stent migration (n = 28), and balloon rupture (n = 13). Peripheral vascular complications included cerebral vascular accidents (CVA) (n = 4), peripheral emboli (n = 1), and significant access arterial injury (n = 13). Older age was significantly associated with occurrence of CVAs. A significant decrease in the technical complication rate from 16.3% to 6.1% (P < 0.001) was observed in procedures performed after January 2002. Conclusions: Stent placement for coarctation of aorta is an effective treatment option, though it remains a technically challenging procedure. Technical and aortic complications have decreased over the past 3 years due to, in part, improvement in balloon and stent design. Improvement in our ability to assess aortic wall compliance is essential prior to placement of ISs in older patients with coarctation of the aorta. © 2007 Wiley-Liss, Inc.

Aortic prosthetic graft infections: radiologic manifestations and implications for management.

Abstract: Prosthetic graft infections are an uncommon complication of aortic bypass. These infections may have serious sequelae such as limb loss and can be lethal. They are hard to eradicate and, under certain circumstances, difficult to diagnose. Usually, computed tomography (CT) is the most efficacious imaging method for diagnosis of graft infections due to its quick availability. The sensitivity of magnetic resonance imaging in detection of perigraft infection has not been thoroughly investigated but is probably similar to that of CT. After the early postoperative period, persistent or expanding perigraft soft tissue, fluid, and gas are the CT findings of graft infection. Aortoenteric fistula should be considered a subset of aortic graft infection; however, perigraft air is more likely to be seen with an aortoenteric fistula. Other conditions associated with graft infection include pseudoaneurysm, hydronephrosis, and osteomyelitis. Adjunctive studies such as sinography, ultrasonography, gallium scanning, and labeled white blood cell scanning can be quite useful in diagnosis, determination of the extent of disease, and selection of the treatment modality. White blood cell scanning is an important complementary test to CT in ambiguous cases, such as in the early postoperative period, and may be more sensitive in detection of early graft infection.

Magnetoencephalographic patterns of epileptiform activity in children with regressive autism spectrum disorders.

Abstract: Background. One-third of children diagnosed with autism spectrum disorders (ASDs) are reported to have had normal early development followed by an autistic regression between the ages of 2 and 3 years. This clinical profile partly parallels that seen in Landau-Kleffner syndrome (LKS), an acquired language disorder (aphasia) believed to be caused by epileptiform activity. Given the additional observation that one-third of autistic children experience one or more seizures by adolescence, epileptiform activity may play a causal role in some cases of autism. Objective. To compare and contrast patterns of epileptiform activity in children with autistic regressions versus classic LKS to determine if there is neurobiological overlap between these conditions. It was hypothesized that many children with regressive ASDs would show epileptiform activity in a multifocal pattern that includes the same brain regions implicated in LKS. Design. Magnetoencephalography (MEG), a noninvasive method for identifying zones of abnormal brain electrophysiology, was used to evaluate patterns of epileptiform activity during stage III sleep in 6 children with classic LKS and 50 children with regressive ASDs with onset between 20 and 36 months of age (16 with autism and 34 with pervasive developmental disorder–not otherwise specified). Whereas 5 of the 6 children with LKS had been previously diagnosed with complex-partial seizures, a clinical seizure disorder had been diagnosed for only 15 of the 50 ASD children. However, all the children in this study had been reported to occasionally demonstrate unusual behaviors (eg, rapid blinking, holding of the hands to the ears, unprovoked crying episodes, and/or brief staring spells) which, if exhibited by a normal child, might be interpreted as indicative of a subclinical epileptiform condition. MEG data were compared with simultaneously recorded electroencephalography (EEG) data, and with data from previous 1-hour and/or 24-hour clinical EEG, when available. Multiple-dipole, spatiotemporal modeling was used to identify sites of origin and propagation for epileptiform transients. Results. The MEG of all children with LKS showed primary or secondary epileptiform involvement of the left intra/perisylvian region, with all but 1 child showing additional involvement of the right sylvian region. In all cases of LKS, independent epileptiform activity beyond the sylvian region was absent, although propagation of activity to frontal or parietal regions was seen occasionally. MEG identified epileptiform activity in 41 of the 50 (82%) children with ASDs. In contrast, simultaneous EEG revealed epileptiform activity in only 68%. When epileptiform activity was present in the ASDs, the same intra/perisylvian regions seen to be epileptiform in LKS were active in 85% of the cases. Whereas primary activity outside of the sylvian regions was not seen for any of the children with LKS, 75% of the ASD children with epileptiform activity demonstrated additional nonsylvian zones of independent epileptiform activity. Despite the multifocal nature of the epileptiform activity in the ASDs, neurosurgical intervention aimed at control has lead to a reduction of autistic features and improvement in language skills in 12 of 18 cases. Conclusions. This study demonstrates that there is a subset of children with ASDs who demonstrate clinically relevant epileptiform activity during slow-wave sleep, and that this activity may be present even in the absence of a clinical seizure disorder. MEG showed significantly greater sensitivity to this epileptiform activity than simultaneous EEG, 1-hour clinical EEG, and 24-hour clinical EEG. The multifocal epileptiform pattern identified by MEG in the ASDs typically includes the same perisylvian brain regions identified as abnormal in LKS. When epileptiform activity is present in the ASDs, therapeutic strategies (antiepileptic drugs, steroids, and even neurosurgery) aimed at its control can lead to a significant improvement in language and autistic features. autism, pervasive developmental disorder–not otherwise specified, epilepsy, magnetoencephalography, Landau-Kleffner syndrome.