The Efficacy of Pectoralis Nerve Blockade in Breast Reductions: A Prospective Randomized Trial.

BACKGROUND: Pectoralis nerve (Pecs) blocks have been shown to reduce perioperative opioid consumption in patients undergoing mastectomies, but the effectiveness of these blocks in breast reductions has not been established. This trial aims to evaluate the efficacy of Pecs blocks (I and II) on perioperative pain management in patients undergoing breast reductions. METHODS: Thirty-six patients were enrolled in the randomized controlled trial divided into 2 groups. The treatment group (n = 16) received general anesthesia plus postinduction ultrasound-guided Pecs blocks. The control group (n = 20) received general anesthesia alone. The primary outcomes measured were perioperative narcotic requirements, need for postoperative antiemetics, pain scores, and length of time in the operating room (OR). We measured patient and procedural risk factors including pedicle/skin excision patterns, concurrent liposuction, weight of resection, and additional local anesthesia. Risk factors as well as outcomes were analyzed using Fischer exact and t tests. RESULTS: No statistically significant difference was shown between the group receiving the Pecs blocks and the control with regard to narcotic requirements, pain scores, and need for antiemetics. Patients undergoing Pecs blocks had a significantly higher OR time before incision (P = 0.0073). Patient and procedural risk factors were well balanced (P > 0.41). CONCLUSIONS: Pectoralis nerve blocks may be a valuable component of a multimodality pain regimen; however, when performed as a solitary adjunct, they do not seem to decrease perioperative narcotic requirements, pain scores, or the need for antiemetic medication in patients undergoing breast reductions. In addition, postinduction Pecs blocks significantly increase OR times.

Quorum-dependent mannopine-inducible conjugative transfer of an Agrobacterium opine-catabolic plasmid.

The Ti plasmid in Agrobacterium tumefaciens strain 15955 carries two alleles of traR that regulate conjugative transfer. The first is a functional allele, called traR, that is transcriptionally induced by the opine octopine. The second, trlR, is a nonfunctional, dominant-negative mutant located in an operon that is inducible by the opine mannopine (MOP). Based on these findings, we predicted that there exist wild-type agrobacterial strains harboring plasmids in which MOP induces a functional traR and, hence, conjugation. We analyzed 11 MOP-utilizing field isolates and found five where MOP induced transfer of the MOP-catabolic element and increased production of the acyl-homoserine lactone (acyl-HSL) quormone. The transmissible elements in these five strains represent a set of highly related plasmids. Sequence analysis of one such plasmid, pAoF64/95, revealed that the 176-kb element is not a Ti plasmid but carries genes for catabolism of MOP, mannopinic acid (MOA), agropinic acid (AGA), and the agrocinopines. The plasmid additionally carries all of the genes required for conjugative transfer, including the regulatory genes traR, traI, and traM. The traR gene, however, is not located in the MOP catabolism region. The gene, instead, is monocistronic and located within the tra-trb-rep gene cluster. A traR mutant failed to transfer the plasmid and produced little to no quormone even when grown with MOP, indicating that TraRpAoF64/95 is the activator of the tra regulon. A traM mutant was constitutive for transfer and acyl-HSL production, indicating that the anti-activator function of TraM is conserved.

Quorum-dependent transfer of the opine-catabolic plasmid pAoF64/95 is regulated by a novel mechanism involving inhibition of the TraR antiactivator TraM.

We previously described a plasmid of Agrobacterium spp., pAoF64/95, in which the quorum-sensing system that controls conjugative transfer is induced by the opine mannopine. We also showed that the quorum-sensing regulators TraR, TraM, and TraI function similarly to their counterparts in other repABC plasmids. However, traR, unlike its counterpart on Ti plasmids, is monocistronic and not located in an operon that is inducible by the conjugative opine. Here, we report that both traR and traM are expressed constitutively and not regulated by growth with mannopine. We report two additional regulatory genes, mrtR and tmsP, that are involved in a novel mechanism of control of TraR activity. Both genes are located in the distantly linked region of pAoF64/95 encoding mannopine utilization. MrtR, in the absence of mannopine, represses the four-gene mocC operon as well as tmsP, which is the distal gene of the eight-gene motA operon. As judged by a bacterial two-hybrid analysis, TmsP, which shows amino acid sequence relatedness with the TraM-binding domain of TraR, interacts with the antiactivator. We propose a model in which mannopine, acting through the repressor MrtR, induces expression of TmsP which then titrates the levels of TraM thereby freeing TraR to activate the tra regulon.

Longitudinal MRI and cognitive change in healthy elderly.

Cross-sectional studies of normal aging indicate an association between memory and hippocampal volume, and between executive functioning and subcortical-frontal circuits. Much less is known, however, about the relationship between longitudinal MRI changes and cognitive decline. The authors hypothesized that longitudinal change in memory would be best predicted by change in hippocampal volumes, whereas change in executive functioning would be best predicted by cortical atrophy and progression of MRI markers of cerebrovascular disease. For this study, 50 healthy elderly subjects underwent structural MRI and cognitive testing at baseline and again at follow-up, with a mean follow-up interval of 45 months. Volumetric MRI measures were hippocampus, cortical gray matter, white matter signal hyperintensity (WMSH), and lacunae. Neuropsychological measures were psychometrically robust composite scores of episodic memory (MEM) and executive functioning (EXEC). Hierarchical multiple regression indicated that a decrease in hippocampus was associated with a decline in MEM, whereas decreased cortical gray matter and increased WMSH were independently associated with a decline in EXEC. Results suggest that in normal aging, cognitive functioning declines as cortical gray matter and hippocampus decrease, and WMSH increases. The association between WMSH and EXEC further highlights the cognitive sequealae associated with cerebrovascular disease in normal elderly.

Factors affecting the rise of treatment of resistant bacteria in skin and soft tissue infections in the United States: 1993-2012.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) prevalence has been steadily increasing for the past 40 years. The increase in such infections has contributed to a change in the treatment patterns of the patient. This study aimed to detail the factors determining prescription practices associated with MRSA-related skin and soft tissue infections. METHODS: The National Ambulatory Medical Care Survey (NAMCS) was searched for data from 1993 to 2012 regarding the factors associated with resistant vs. non-resistant-antibiotic prescription. RESULTS: Of all physician visits, 34.0% received resistant-antibiotic therapy and 66.0% received non-resistant-antibiotic therapy. Prescription of antibiotic-resistant therapy increased over the time period studied (Odds ratio (OR) = 1.07; 95% CI 1.05, 1.09; p < .0001). Logistic regression controlling for age, sex, race, region, metropolitan statistical area (MSA), infection type, physician specialty, number of medications and number of diagnoses found that region, infection type and physician specialty were factors in the prescription patterns of SSTIs. In the Northeast, patients were less likely to be prescribed resistant-antibiotics (OR = 0.25; 0.12, 0.53; p = .0003), non-primary care physicians were more likely to prescribe resistant-antibiotics (OR = 2.89; 1.75, 4.77; p < .0001), and patients presenting with folliculitis were more likely to be prescribed resistant antibiotics (OR = 3.03; 1.30, 7.05; p = .01). CONCLUSIONS: With the increasing prevalence of MRSA-related SSTIs, the treatment of these infections is changing. Understanding of the factors contributing to the prescription of resistant antibiotics could aid in the selection of appropriate treatment of SSTIs, and hopefully, avoidance of development of additionally resistant organisms.

The repABC Plasmids with Quorum-Regulated Transfer Systems in Members of the Rhizobiales Divide into Two Structurally and Separately Evolving Groups.

The large repABC plasmids of the order Rhizobiales with Class I quorum-regulated conjugative transfer systems often define the nature of the bacterium that harbors them. These otherwise diverse plasmids contain a core of highly conserved genes for replication and conjugation raising the question of their evolutionary relationships. In an analysis of 18 such plasmids these elements fall into two organizational classes, Group I and Group II, based on the sites at which cargo DNA is located. Cladograms constructed from proteins of the transfer and quorum-sensing components indicated that those of the Group I plasmids, while coevolving, have diverged from those coevolving proteins of the Group II plasmids. Moreover, within these groups the phylogenies of the proteins usually occupy similar, if not identical, tree topologies. Remarkably, such relationships were not seen among proteins of the replication system; although RepA and RepB coevolve, RepC does not. Nor do the replication proteins coevolve with the proteins of the transfer and quorum-sensing systems. Functional analysis was mostly consistent with phylogenies. TraR activated promoters from plasmids within its group, but not between groups and dimerized with TraR proteins from within but not between groups. However, oriT sequences, which are highly conserved, were processed by the transfer system of plasmids regardless of group. We conclude that these plasmids diverged into two classes based on the locations at which cargo DNA is inserted, that the quorum-sensing and transfer functions are coevolving within but not between the two groups, and that this divergent evolution extends to function.