Casimir force on amplifying bodies

Based on a unified approach to macroscopic QED that allows for the inclusion of amplification in a limited space and frequency range, we study the Casimir force as a Lorentz force on an arbitrary partially amplifying system of linearly locally responding (isotropic) magnetoelectric bodies. We demonstrate that the force on a weakly polarisable/magnetisable amplifying object in the presence of a purely absorbing environment can be expressed as a sum over the Casimir--Polder forces on the excited atoms inside the body. As an example, the resonant force between a plate consisting of a dilute gas of excited atoms and a perfect mirror is calculated

Gram-Negative Rod Skin and Soft-tissue infections following Breast Tissue Expander Surgery in Breast Cancer Patients

Background: Breast cancer patients who undergo tissue expander surgery (TES) are at an increased risk of developing gram-negative rod (GNR) skin and soft-tissue infection (SSIs) and its complications including prolonged antibiotic therapy, antibiotics side effects, and implant removal. Current perioperative antimicrobials focus mostly on gram-positive organisms, but the presence of a foreign body increases the risk of GNR SSI. We describe here the most common GNR bacteria and their susceptibility patterns that cause SSI after TES among breast cancer patients. Methods: We conducted a retrospective cohort study at Moffitt Cancer Center, Tampa, FL from January 2016, to January 2018, on all breast cancer patients who developed GNR SSIs following TES. We reviewed records after approval from the Institutional Review Board. The data collected included patient’s age, pathogens from wound culture, antibiotic susceptibilities, the perioperative and definitive antibiotics used. Results: A total of 38 cases of GNR SSI with a mean age of 56 ± 11 years were identified. The 3 most common pathogens were Pseudomonas aeruginosa (45%), Serratia marcescens (16%), and Klebsiella pneumoniae (8%) (Figure 1). The susceptibility pattern was available for 33 cases. Pseudomonas and Klebsiella isolates were susceptible to all tested antibiotics (Table 1). The Stenotrophomonas isolates showed resistance to ceftazidime. Enterobacter cloacae, Enterobacter aerogenes, Morganella morganii, and Acinetobacter baumannii complex, showed resistance to cefazolin. Twenty-five cases (74%) received perioperative antibiotics for gram-positive organisms; mostly cefazolin, and vancomycin. The common antibiotics used for definitive treatment were ciprofloxacin, cefepime, ceftazidime, piperacillin–tazobactam, and meropenem. Conclusion: In centers with a high percentage of GNR SSI following TES should consider using perioperative antibiotics that include coverage against Pseudomonas aeruginosa, the most common isolate (45%). The use only of cefazolin or other antibiotics against gram-positive organism may be inadequate. However, GNR infection may occur from 48 hours to 2 weeks postoperatively and may be from the acquisition of the GNR at home in which perioperative antibiotics may have minimal effect

Differential effects of two MRI contrast agents on the integrity and distribution of rAAV2 and rAAV5 in the rat striatum

Intraoperative magnetic resonance imaging (MRI) has been proposed as a method to optimize intracerebral targeting and for tracking infusate distribution in gene therapy trials for nervous system disorders. We thus investigated possible effects of two MRI contrast agents, gadoteridol (Gd) and galbumin (Gab), on the distribution and levels of transgene expression in the rat striatum and their effect on integrity and stability of recombinant adeno-associated virus (rAAV) particles. MRI studies showed that contrast agent distribution did not predict rAAV distribution. However, green fluorescent protein (GFP) immunoreactivity revealed an increase in distribution of rAAV5-GFP, but not rAAV2-GFP, in the presence of Gd when compared with viral vector injected alone. In contrast, Gab increased the distribution of rAAV2-GFP not rAAV5-GFP. These observations pointed to a direct effect of infused contrast agent on the rAAV particles. Negative-stain electron microscopy (EM), DNAase treatment, and differential scanning calorimetry (DSC) were used to monitor rAAV2 and rAAV5 particle integrity and stability following contrast agent incubation. EMs of rAAV2-GFP and rAAV5-GFP particles pretreated with Gd appear morphologically similar to the untreated sample; however, Gab treatment resulted in surface morphology changes and aggregation. A compromise of particle integrity was suggested by sensitivity of the packaged genome to DNAase treatment following Gab incubation but not Gd for both vectors. However, neither agent significantly affected particle stability when analyzed by DSC. An increase in Tm was observed for AAV2 in lactated Ringer's buffer. These results thus highlight potential interactions between MRI contrast agents and AAV that might affect vector distribution and stability, as well as the stabilizing effect of lactated Ringer's solution on AAV2

Gram-Negative Rod Skin and Soft-tissue infections following Breast Tissue Expander Surgery in Breast Cancer Patients

Background: Breast cancer patients who undergo tissue expander surgery (TES) are at an increased risk of developing gram-negative rod (GNR) skin and soft-tissue infection (SSIs) and its complications including prolonged antibiotic therapy, antibiotics side effects, and implant removal. Current perioperative antimicrobials focus mostly on gram-positive organisms, but the presence of a foreign body increases the risk of GNR SSI. We describe here the most common GNR bacteria and their susceptibility patterns that cause SSI after TES among breast cancer patients. Methods: We conducted a retrospective cohort study at Moffitt Cancer Center, Tampa, FL from January 2016, to January 2018, on all breast cancer patients who developed GNR SSIs following TES. We reviewed records after approval from the Institutional Review Board. The data collected included patient’s age, pathogens from wound culture, antibiotic susceptibilities, the perioperative and definitive antibiotics used. Results: A total of 38 cases of GNR SSI with a mean age of 56 ± 11 years were identified. The 3 most common pathogens were Pseudomonas aeruginosa (45%), Serratia marcescens (16%), and Klebsiella pneumoniae (8%) (Figure 1). The susceptibility pattern was available for 33 cases. Pseudomonas and Klebsiella isolates were susceptible to all tested antibiotics (Table 1). The Stenotrophomonas isolates showed resistance to ceftazidime. Enterobacter cloacae, Enterobacter aerogenes, Morganella morganii, and Acinetobacter baumannii complex, showed resistance to cefazolin. Twenty-five cases (74%) received perioperative antibiotics for gram-positive organisms; mostly cefazolin, and vancomycin. The common antibiotics used for definitive treatment were ciprofloxacin, cefepime, ceftazidime, piperacillin–tazobactam, and meropenem. Conclusion: In centers with a high percentage of GNR SSI following TES should consider using perioperative antibiotics that include coverage against Pseudomonas aeruginosa, the most common isolate (45%). The use only of cefazolin or other antibiotics against gram-positive organism may be inadequate. However, GNR infection may occur from 48 hours to 2 weeks postoperatively and may be from the acquisition of the GNR at home in which perioperative antibiotics may have minimal effect

The effects of resistance training with or without peanut protein supplementation on skeletal muscle and strength adaptations in older individuals

Several studies suggest resistance training (RT) while supplementing with various protein supplements can enhance strength and muscle mass in older individuals. However, to date, no study has examined the effects of RT with a peanut protein powder (PP) supplement on these outcomes. Herein, 39 older, untrained individuals (n = 17 female, n = 22 male; age = 58.6 ± 8.0 years; body mass index =28.7 ± 5.8) completed a 6-week (n = 22) or 10-week (n = 17) RT program, where full-body training was implemented twice weekly (ClinicalTrials.gov trial registration NCT04015479; registered July 11, 2019). Participants in each program were randomly assigned to consume either a PP supplement once per day (75 total g powder providing 30 g protein, > 9.2 g essential amino acids, ~ 315 kcal; n = 20) or no supplement (CTL; n = 19). Right leg vastus lateralis (VL) muscle biopsies were obtained prior to and 24 h following the first training bout in all participants to assess the change in myofibrillar protein synthetic rates (MyoPS) as measured via the deuterium-oxide (D2O) tracer method. Pre- and Post-intervention testing in all participants was conducted using dual energy x-ray absorptiometry (DXA), VL ultrasound imaging, a peripheral quantitative computed tomography (pQCT) scan at the mid-thigh, and right leg isokinetic dynamometer assessments. Integrated MyoPS rates over a 24-h period were not significantly different (p < 0.05) between supplement groups following the first training bout. Regarding chronic changes, there were no significant supplement-by-time interactions in DXA-derived fat mass, lean soft tissue mass or percent body fat between supplementation groups. There was, however, a significant increase in VL thickness in PP versus CTL participants when the 6- and 10-week cohorts were pooled (interaction p = 0.041). There was also a significant increase in knee flexion torque in the 10-week PP group versus the CTL group (interaction p = 0.032). In conclusion, a higher-protein, defatted peanut powder supplement in combination with RT positively affects select markers of muscle hypertrophy and strength in an untrained, older adult population. Moreover, subanalyses indicated that gender did not play a role in these adaptations