Comparison of the efficacy of nifedipine with ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor: a systematic review and meta-analysis.

BACKGROUND: Some studies have compared the efficacy of nifedipine with that of other tocolytic drugs in the treatment of preterm labor, but the reported results are conflicting. OBJECTIVE: To compare the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor. METHODS: In this systematic review and meta-analysis, PubMed/MEDLINE, Scopus, Clarivate Analytics Web of Science, and Google Scholar were searched until April 3,2024 using predefined keywords. Randomized controlled trials (RCTs) and clinical trials that compared the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor were included. Two authors independently reviewed the articles, assessed their quality and extracted the data. The quality of the included RCTs based on the Cochrane Risk of Bias Tool 1 for clinical trial studies. The risk difference (RD) with the associated 95% confidence interval (CI) was calculated. A forest plot diagram was used to show the comparative point estimates of nifedipine and other tocolytic drugs on the prevention of preterm labor and their associated 95% confidence intervals based on the duration of pregnancy prolongation. Study heterogeneity was evaluated by the I2 index, and publication bias was evaluated by Egger's test. RESULTS: Forty studies enrolling 4336 women were included. According to our meta-analysis, there was a significant difference in the prolongation of preterm labor within the first 48 h between the nifedipine group and the nitroglycerine group (RD, -0.04; 95% CI, -0.08 to -0.00; I2: 32.3%). Additionally, there were significant differences between nifedipine and ritodrine (RD, 0.11; 95% CI, 0.02 to 0.21; I2, 51.2%) for more than one week RD, 0.10; 95% CI, 0.03 to 0.19; I2, 33.2%) and for 34 weeks and more. The difference between nifedipine and magnesium sulfate was not significant in any of the four time points. CONCLUSIONS: Considering the superiority of nifedipine over ritodrine and nitroglycerine and its similar efficacy to magnesium sulfate for tocolysis, it seems that the side effects of these options determine the first drug line.

Minimal gene set from Sinorhizobium (Ensifer) meliloti pSymA required for efficient symbiosis with Medicago.

Reduction of N2 gas to ammonia in legume root nodules is a key component of sustainable agricultural systems. Root nodules are the result of a symbiosis between leguminous plants and bacteria called rhizobia. Both symbiotic partners play active roles in establishing successful symbiosis and nitrogen fixation: while root nodule development is mostly controlled by the plant, the rhizobia induce nodule formation, invade, and perform N2 fixation once inside the plant cells. Many bacterial genes involved in the rhizobia-legume symbiosis are known, and there is much interest in engineering the symbiosis to include major nonlegume crops such as corn, wheat, and rice. We sought to identify and combine a minimal bacterial gene complement necessary and sufficient for symbiosis. We analyzed a model rhizobium, Sinorhizobium (Ensifer) meliloti, using a background strain in which the 1.35-Mb symbiotic megaplasmid pSymA was removed. Three regions representing 162 kb of pSymA were sufficient to recover a complete N2-fixing symbiosis with alfalfa, and a targeted assembly of this gene complement achieved high levels of symbiotic N2 fixation. The resulting gene set contained just 58 of 1,290 pSymA protein-coding genes. To generate a platform for future synthetic manipulation, the minimal symbiotic genes were reorganized into three discrete nod, nif, and fix modules. These constructs will facilitate directed studies toward expanding the symbiosis to other plant partners. They also enable forward-type approaches to identifying genetic components that may not be essential for symbiosis, but which modulate the rhizobium's competitiveness for nodulation and the effectiveness of particular rhizobia-plant symbioses.

Superior Vector Plication of the Mobile Anterior Midface: The Delta Facelift.

BACKGROUND: Traditional plication techniques have been ineffective in addressing the anterior midface when compared to the sub-superficial musculoaponeurotic system (SMAS) "deep plane" approaches. However, by moving the plication much closer to the mobile medial fat tissues, a more effective and long-lasting plication can be accomplished without releasing the SMAS layer. OBJECTIVES: The authors' "Delta facelift" approach combines a rotation vertical advancement of the midface fat with a dual-vector platysmaplasty and deep cervicoplasty as indicated for a harmoniously youthful neck. METHODS: A retrospective chart review was performed on all patients who underwent facial rejuvenation with the Delta facelift technique between January 1, 2012, and May 30, 2021, for patient demographics, procedure details, outcomes, and complications. RESULTS: A total of 283 patients underwent Delta facelift (273 females, 10 males). The average age was 60.8 years old. Primary facelift was performed in 229 patients, whereas 54 facelifts were secondary or further procedures. Adjunctive procedures included autologous fat grafting (93%), blepharoplasty (52%), and skin rejuvenating procedures (35%). There were 11 self-resolving neuropraxias, 6 minor hematomas, and 6 infections. Nine patients underwent repeat Delta facelift at an average of 9.3 years. CONCLUSIONS: The Delta rotation vertical advancement of the anterior facial fat counters the descent and deflation associated with facial aging. Dual-vector platysmaplasty, with or without myotomy, effectively manages the jowl and delineates the jawline. Addition of deep cervicoplasty is recommended for patients with oblique necks or those with subplatysmal volume excess.

Sexual function after childbirth: a meta-analysis based on mode of delivery.

Although many women report sexual dysfunction in the postpartum period, controversial research has been reported the relationship between delivery mode and sexual function. This meta-analysis aimed to investigate the sexual function after childbirth and identify the difference of sexual function based on the female sexual function index (FSFI) questionnaire in women with elective cesarean section, vaginal delivery with episiotomy and vaginal delivery without episiotomy. Studies were found by searching in Medline, PubMed, Web of Science, Scopus and considering the references of the related papers from their start dates until September 2021. All observational studies in English that reported the mean and SD of score of sexual function and its domains based on the mode of delivery were included in this meta-analysis. Random effect model was used to combine the results of included studies on female sexual function and its subdomains. Finally, 17 articles with a total population of 3410 were included in the meta-analysis. Total mean (95 percent CI) of sexual function was 24.27 (22.82, 25.72) with substantial heterogeneity among studies (χ2 = 7487.63, P < .001; I2 = 99.45). In subgroup analyses, the mean score of sexual function was significantly differed in terms of time elapsed since delivery (P = .04) and studied country (P < .001). But, the mode of delivery has no significant effect on postpartum sexual function and subdomains. The result indicated that elective cesarean section, vaginal delivery with episiotomy, vaginal delivery without episiotomy are not associated with the female sexual function.

The association of mode of delivery and dyspareunia: a systematic review and meta-analysis.

This meta-analysis aimed to examine the association between the mode of delivery and dyspareunia worldwide. Epidemiologic studies evaluating the link between the mode of delivery and dyspareunia (published up to July 2019) were included in this research. These studies were selected by searching several databases such as MEDLINE, ClinicalTraial.gov, PubMed, Web of Science, Scopus and Google Scholar and considering the list of selected articles extracted from references. Then, meta-analyses, subgroup analyses and meta-regressions of the studies were conducted to evaluate the association between the mode of delivery and dyspareunia. In this study, 23 out of 1099 articles were identified and used in the final analysis. Dyspareunia differed according to the mode of delivery although this difference was not statistically significant. In terms of the mode of delivery, a difference was found between instrumental vaginal delivery and caesarean section, but it was not significant. It seems that more studies with a larger sample size should be considered to determine the difference.

The effectiveness of "Women's Postpartum Sexual Health Program (WPSHP)" on Iranian women's postpartum sexual health: A randomized clinical trial.

In this study, we examined the effectiveness of Women's Postpartum Sexual Health Program (WPSHP) on Iranian women's sexual health in the postpartum period. A single-blinded randomized clinical trial was conducted in 2016 on 80 postnatal women in Iran. We used the Female Sexual Function Index, Sexual Quality of Life - Female questionnaire and Female Sexual Distress Scale. The intervention group received counseling based on WPSHP. After 28 weeks, the mean score of the Female Sexual Function Index and Female Sexual Quality of Life significantly increased in the WPSH group (p < 0.001, p < 0.001), while the mean score of the Female Sexual Distress significantly decreased in the WPSH group (p < 0.001). We concluded that Women's Postpartum Sexual Health Program could promote postnatal women's sexual function and female sexual quality of life and reduces female sexual distress in women suffering from sexual problems in the postpartum period.

Mutations in SARS-CoV-2; Consequences in structure, function, and pathogenicity of the virus.

The third pandemic of coronavirus infection, called COVID-19 disease, began recently in China. The newly discovered coronavirus, entitled SARS-CoV-2, is the seventh member of the human coronaviruses. The main pathogenesis of SARS-CoV-2 infection is severe pneumonia, RNAaemia, accompanied by glass turbidity, and acute cardiac injury. It possesses a single-stranded positive-sense RNA genome which is 60-140 nm in diameter, and has a size of 26-32 kbp. Viral pathogenesis is accomplished with spike glycoprotein through the employment of a membrane-bound aminopeptidase, called the ACE2, as its primary cell receptor. It has been confirmed that various factors such as different national rules for quarantine and various races or genetic backgrounds might influence the mortality and infection rate of COVID-19 in the geographic areas. In addition to various known and unknown factors and host genetic susceptibility, mutations and genetic variabilities of the virus itself have a critical impact on variable clinical features of COVID-19. Although the SARS-CoV-2 genome is more stable than SARS-CoV or MERS-CoV, it has a relatively high dynamic mutation rate with respect to other RNA viruses. It's noteworthy that, some mutations can be founder mutations and show specific geographic patterns. Undoubtedly, these mutations can drive viral genetic variability, and because of genotype-phenotype correlation, resulting in a virus with more/lower/no decrease in natural pathogenic fitness or on the other scenario, facilitating their rapid antigenic shifting to escape the host immunity and also inventing a drug resistance virus, so converting it to a more infectious or deadly virus. Overall, the detection of all mutations in SARS-CoV-2 and their relations with pathological changes is nearly impossible, mostly due to asymptomatic subjects. In this review paper, the reported mutations of the SARS-CoV-2 and related variations in virus structure and pathogenicity in different geographic areas and genotypes are widely investigated. Many studies need to be repeated in other regions/locations for other people to confirm the findings. Such studies could benefit patient-specific therapy, according to genotyping patterns of SARS-CoV-2 distribution.

Early Postoperative Complications From National Surgical Quality Improvement Program: A Closer Examination of Timing and Technique of Breast Reconstruction.

BACKGROUND: Despite the recent surge in rates of immediate breast reconstruction, there is a paucity of large multicenter studies to compare differences in morbidity after immediate versus delayed breast reconstruction. This study used the National Surgical Quality Improvement Program (NSQIP) to study the association between timing of breast reconstruction and complication rates, stratified by reconstructive modality. STUDY DESIGN: The NSQIP database was used to identify breast reconstructions from 2005 to 2012. Rates of major complications were compared by timing within each reconstructive modality (implant vs autologous). Cohort differences in baseline characteristics and variables associated with increased complication rates were identified in bivariate analyses. A multivariable model was created to compare the association between the timing of reconstruction and major complications. RESULTS: Of 24,506 postmastectomy reconstructions, 85.8% were immediate, 14.2% were delayed, 84% were implant, and 16% were autologous reconstructions. Overall, 10.0% of patients suffered a major complication. After stratification, only implant reconstructions showed a statistically higher complication rate with immediate (8.8%) reconstruction compared with delayed (5.3%) (odds ratio, 1.7, P < 0.01). There was no significant difference in complication rates between autologous immediate (18.4%) or delayed (19.0%) reconstructions. After controlling for baseline cohort differences and other risk factors, immediate reconstruction remained as an independent significant predictor of major complications in implant reconstructions (odds ratio, 1.8, P < 0.01). CONCLUSIONS: Immediate rather than delayed breast reconstruction is associated with a significantly higher rate of major complications in implant reconstruction but not in autologous reconstruction. It is important to include these findings in the routine preoperative surgeon-patient discussion of reconstructive options.

The Safe Resumption of Elective Plastic Surgery in Accredited Ambulatory Surgery Facilities During the COVID-19 Pandemic.

BACKGROUND: On March 11, 2020, the World Health Organization declared the novel Coronavirus-19 (COVID-19) a worldwide pandemic, resulting in an unprecedented shift in the Canadian healthcare system, where protection of an already overloaded system became a priority; all elective surgeries and non-essential activities were ceased. With the impact being less than predicted, on May 26, 2020, elective surgeries and non-essential activities were permitted to resume. OBJECTIVES: The authors sought to examine outcomes following elective aesthetic surgery and the impact on the Canadian healthcare system with the resumption of these services during the COVID-19 worldwide pandemic. METHODS: Data were collected in a prospective manner on consecutive patients who underwent elective plastic surgery procedures in 6 accredited ambulatory surgery facilities. Data included patient demographics, procedural characteristics, COVID-19 polymerase chain reaction (PCR) test status, airway management, and postoperative outcomes. RESULTS: A total of 368 patients underwent elective surgical procedures requiring a general anesthetic. All 368 patients who underwent surgery were negative on pre-visit screening. A COVID-19 PCR test was completed by 352 patients (95.7%) and all were negative. In the postoperative period, 7 patients (1.9%) had complications, 3 patients (0.8%) required a hospital visit, and 1 patient (0.3%) required hospital admission. No patients or healthcare providers developed COVID-19 symptoms or had a positive test for COVID-19 within 30 days of surgery. CONCLUSIONS: With appropriate screening and safety precautions, elective aesthetic plastic surgery can be performed in a manner that is safe for patients and healthcare providers and with a very low risk for accelerating virus transmission within the community.

Does Implant Surface Texture Affect the Risk of Capsular Contracture in Subglandular Breast Augmentation and Breast Augmentation-Mastopexy?

BACKGROUND: Previous studies have reported decreased rates of capsular contracture associated with the use of textured surface breast implants placed in the subglandular plane during breast augmentation. However, since the publication of these studies, our understanding of the pathophysiology of capsular contracture, as well as the surgical techniques utilized to minimize bacterial contamination of the implant, have advanced considerably. OBJECTIVES: The purpose of this study was to re-evaluate the relation between implant surface texturization and capsular contracture rates for breast implants placed in the subglandular plane during primary breast augmentation. METHODS: Retrospective chart review was performed of all primary subglandular breast augmentation procedures involving the use of either smooth or textured round silicone gel implants, with or without simultaneous mastopexy. The primary outcome measures included clinically significant capsular contracture (Baker grade III/IV) and revision surgery for capsular contracture. RESULTS: Between 2010 and 2017, 526 patients underwent primary subglandular breast augmentation with either smooth (n = 212) or textured (n = 314) round silicone gel implants; 248 patients underwent breast augmentation, whereas 278 underwent breast augmentation-mastopexy. Average follow-up was 756 days in the textured group and 461 days in the smooth group. Five cases of capsular contracture were observed in the textured group, and 7 cases of capsular contracture were observed in the smooth group (P = 0.20). CONCLUSIONS: Smooth surface implants placed in the subglandular plane were not at a significantly increased risk of capsular contracture compared with textured surface implants. We suggest that adherence to a surgical technique focused on minimizing bacterial contamination of the implant is of greater clinical significance than implant surface characteristics when discussing capsular contracture.

Multidisciplinary approaches for studying rhizobium-legume symbioses.

The rhizobium-legume symbiosis is a major source of fixed nitrogen (ammonia) in the biosphere. The potential for this process to increase agricultural yield while reducing the reliance on nitrogen-based fertilizers has generated interest in understanding and manipulating this process. For decades, rhizobium research has benefited from the use of leading techniques from a very broad set of fields, including population genetics, molecular genetics, genomics, and systems biology. In this review, we summarize many of the research strategies that have been employed in the study of rhizobia and the unique knowledge gained from these diverse tools, with a focus on genome- and systems-level approaches. We then describe ongoing synthetic biology approaches aimed at improving existing symbioses or engineering completely new symbiotic interactions. The review concludes with our perspective of the future directions and challenges of the field, with an emphasis on how the application of a multidisciplinary approach and the development of new methods will be necessary to ensure successful biotechnological manipulation of the symbiosis.

Periareolar Augmentation-Mastopexy.

The authors describe their surgical technique for single-stage periareolar mastopexy with subglandular breast augmentation. They have performed this procedure in 85 patients since 2009 and found that this operative technique has allowed them to achieve reproducible outcomes in a single-stage procedure. Periareolar mastopexy with subglandular breast augmentation is an excellent procedure for patients who desire a larger breast size and who present with mild to moderate nipple ptosis with a paucity of excess skin in the lower pole of the breast. This article will review the perioperative management and detailed steps of the procedure and outline its indications for utilization and some of the common complications the authors have encountered.

PhoU Allows Rapid Adaptation to High Phosphate Concentrations by Modulating PstSCAB Transport Rate in Sinorhizobium meliloti.

Maintenance of cellular phosphate homeostasis is essential for cellular life. The PhoU protein has emerged as a key regulator of this process in bacteria, and it is suggested to modulate phosphate import by PstSCAB and control activation of the phosphate limitation response by the PhoR-PhoB two-component system. However, a proper understanding of PhoU has remained elusive due to numerous complications of mutating phoU, including loss of viability and the genetic instability of the mutants. Here, we developed two sets of strains of Sinorhizobium meliloti that overcame these limitations and allowed a more detailed and comprehensive analysis of the biological and molecular activities of PhoU. The data showed that phoU cannot be deleted in the presence of phosphate unless PstSCAB is inactivated also. However, phoU deletions were readily recovered in phosphate-free media, and characterization of these mutants revealed that addition of phosphate to the environment resulted in toxic levels of PstSCAB-mediated phosphate accumulation. Phosphate uptake experiments indicated that PhoU significantly decreased the PstSCAB transport rate specifically in phosphate-replete cells but not in phosphate-starved cells and that PhoU could rapidly respond to elevated environmental phosphate concentrations and decrease the PstSCAB transport rate. Site-directed mutagenesis results suggested that the ability of PhoU to respond to phosphate levels was independent of the conformation of the PstSCAB transporter. Additionally, PhoU-PhoU and PhoU-PhoR interactions were detected using a bacterial two-hybrid screen. We propose that PhoU modulates PstSCAB and PhoR-PhoB in response to local, internal fluctuations in phosphate concentrations resulting from PstSCAB-mediated phosphate import.IMPORTANCE Correct maintenance of cellular phosphate homeostasis is critical in all kingdoms of life and in bacteria involves the PhoU protein. This work provides novel insights into the role of the Sinorhizobium meliloti PhoU protein, which plays a key role in rapid adaptation to elevated phosphate concentrations. It is shown that PhoU rapidly responds to elevated phosphate levels by significantly decreasing the phosphate transport of PstSCAB, thereby preventing phosphate toxicity and cell death. Additionally, a new model for phosphate sensing in bacterial species which involves the PhoR-PhoB two-component system is presented. This work provides new insights into the bacterial response to changing environmental conditions and into regulation of the phosphate limitation response that influences numerous bacterial processes, including antibiotic production and virulence.

Heterologous Complementation Reveals a Specialized Activity for BacA in the Medicago-Sinorhizobium meliloti Symbiosis.

The bacterium Sinorhizobium meliloti Rm2011 forms N2-fixing root nodules on alfalfa and other leguminous plants. The pSymB chromid contains a 110-kb region (the ETR region) showing high synteny to a chromosomally located region in Sinorhizobium fredii NGR234 and related rhizobia. We recently introduced the ETR region from S. fredii NGR234 into the S. meliloti chromosome. Here, we report that, unexpectedly, the S. fredii NGR234 ETR region did not complement deletion of the S. meliloti ETR region in symbiosis with Medicago sativa. This phenotype was due to the bacA gene of NGR234 not being functionally interchangeable with the S. meliloti bacA gene during M. sativa symbiosis. Further analysis revealed that, whereas bacA genes from S. fredii or Rhizobium leguminosarum bv. viciae 3841 failed to complement the Fix- phenotype of a S. meliloti bacA mutant with M. sativa, they allowed for further developmental progression prior to a loss of viability. In contrast, with Melilotus alba, bacA from S. fredii and R. leguminosarum supported N2 fixation by a S. meliloti bacA mutant. Additionally, the S. meliloti bacA gene can support N2 fixation of a R. leguminosarum bacA mutant during symbiosis with Pisum sativum. A phylogeny of BacA proteins illustrated that S. meliloti BacA has rapidly diverged from most rhizobia and has converged toward the sequence of pathogenic genera Brucella and Escherichia. These data suggest that the S. meliloti BacA has evolved toward a specific interaction with Medicago and highlights the limitations of using a single model system for the study of complex biological topics.

A putative 3-hydroxyisobutyryl-CoA hydrolase is required for efficient symbiotic nitrogen fixation in Sinorhizobium meliloti and Sinorhizobium fredii NGR234.

We report that the smb20752 gene of the alfalfa symbiont Sinorhizobium meliloti is a novel symbiotic gene required for full N2 -fixation. Deletion of smb20752 resulted in lower nitrogenase activity and smaller nodules without impacting overall nodule morphology. Orthologs of smb20752 were present in all alpha and beta rhizobia, including the ngr_b20860 gene of Sinorhizobium fredii NGR234. A ngr_b20860 mutant formed Fix- determinate nodules that developed normally to a late stage of the symbiosis on the host plants Macroptilium atropurpureum and Vigna unguiculata. However an early symbiotic defect was evident during symbiosis with Leucaena leucocephala, producing Fix- indeterminate nodules. The smb20752 and ngr_b20860 genes encode putative 3-hydroxyisobutyryl-CoA (HIB-CoA) hydrolases. HIB-CoA hydrolases are required for l-valine catabolism and appear to prevent the accumulation of toxic metabolic intermediates, particularly methacrylyl-CoA. Evidence presented here and elsewhere (Curson et al., , PLoS ONE 9:e97660) demonstrated that Smb20752 and NGR_b20860 can also prevent metabolic toxicity, are required for l-valine metabolism, and play an undefined role in 3-hydroxybutyrate catabolism. We present evidence that the symbiotic defect of the HIB-CoA hydrolase mutants is independent of the inability to catabolize l-valine and suggest it relates to the toxicity resulting from metabolism of other compounds possibly related to 3-hydroxybutyric acid.

Genomic resources for identification of the minimal N2 -fixing symbiotic genome.

The lack of an appropriate genomic platform has precluded the use of gain-of-function approaches to study the rhizobium-legume symbiosis, preventing the establishment of the genes necessary and sufficient for symbiotic nitrogen fixation (SNF) and potentially hindering synthetic biology approaches aimed at engineering this process. Here, we describe the development of an appropriate system by reverse engineering Sinorhizobium meliloti. Using a novel in vivo cloning procedure, the engA-tRNA-rmlC (ETR) region, essential for cell viability and symbiosis, was transferred from Sinorhizobium fredii to the ancestral location on the S. meliloti chromosome, rendering the ETR region on pSymB redundant. A derivative of this strain lacking both the large symbiotic replicons (pSymA and pSymB) was constructed. Transfer of pSymA and pSymB back into this strain restored symbiotic capabilities with alfalfa. To delineate the location of the single-copy genes essential for SNF on these replicons, we screened a S. meliloti deletion library, representing > 95% of the 2900 genes of the symbiotic replicons, for their phenotypes with alfalfa. Only four loci, accounting for < 12% of pSymA and pSymB, were essential for SNF. These regions will serve as our preliminary target of the minimal set of horizontally acquired genes necessary and sufficient for SNF.

Proline auxotrophy in Sinorhizobium meliloti results in a plant-specific symbiotic phenotype.

In order to effectively manipulate rhizobium-legume symbioses for our benefit, it is crucial to first gain a complete understanding of the underlying genetics and metabolism. Studies with rhizobium auxotrophs have provided insight into the requirement for amino acid biosynthesis during the symbiosis; however, a paucity of available L-proline auxotrophs has limited our understanding of the role of L-proline biosynthesis. Here, we examined the symbiotic phenotypes of a recently described Sinorhizobium meliloti L-proline auxotroph. Proline auxotrophy was observed to result in a host-plant-specific phenotype. The S. meliloti auxotroph displayed reduced symbiotic capability with alfalfa (Medicago sativa) due to a decrease in nodule mass formed and therefore a reduction in nitrogen fixed per plant. However, the proline auxotroph formed nodules on white sweet clover (Melilotus alba) that failed to fix nitrogen. The rate of white sweet clover nodulation by the auxotroph was slightly delayed, but the final number of nodules per plant was not impacted. Examination of white sweet clover nodules by confocal microscopy and transmission electron microscopy revealed the presence of the S. meliloti proline auxotroph cells within the host legume cells, but few differentiated bacteroids were identified compared with the bacteroid-filled plant cells of WT nodules. Overall, these results indicated that L-proline biosynthesis is a general requirement for a fully effective nitrogen-fixing symbiosis, likely due to a transient requirement during bacteroid differentiation.

Peripheral nerve injury after local anesthetic injection.

BACKGROUND: A well-known complication of peripheral nerve block is peripheral nerve injury, whether from the needle or toxicity of the medication used. In this study, we sought to determine the extent of damage that results from intrafascicular injection of various commonly used local anesthetics (LAs). METHODS: Sixteen Lewis rats received an intrafascicular injection of saline (control) or 1 of 3 LAs (bupivacaine, lidocaine, or ropivacaine) into the sciatic nerve (n = 4). At a 2-week end point, the sciatic nerves were harvested for histomorphometric and electron microscopic analysis. RESULTS: Animals that received intrafascicular LA injections showed increased severity of injury as compared with control. In particular, there was a significant loss of large-diameter fibers as indicated by decreased counts (P < 0.01 for all LAs) and area (P < 0.01 for all LAs) of remaining fibers in severely injured versus noninjured areas of the nerve. There was a layering of severity of injury with most severely injured areas closest to and noninjured areas furthest from the injection site. Bupivacaine caused more damage to large fibers than the other 2 LAs. In all groups, fascicular transection injury from the needle was observed. Electron microscopy confirmed nerve injury. CONCLUSIONS: Frequently used LAs at traditional concentrations are toxic to and can injure the peripheral nerve. Any combination of motor and/or sensory sequelae may result due to the varying fascicular topography of a nerve.