EXPERIMENTAL MODEL FOR TREATMENT OF EXTENDED SPECTRUM BETALACTAMASE PRODUCING-KLEBSIELLA PNEUMONIAE

Background

Animal models are useful to evaluate the efficacy of antimicrobials in experimental sepsis.

Aim

To elucidate the steps of producing an experimental model for the treatment of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae sepsis

Methods

Several ESBL inoculums ranging from 1.5x10⁹ colony-forming units per milliliter (CFU/mL) to 2.0x10¹⁰CFU/mL were administered by peritoneal injection in adults Wistar rats. Outcomes and microbiological data of quantitative peritoneal and blood cultures were observed in untreated animals. Animals which received 2.0x10¹⁰CFU/mL inoculums were treated with single meropenem dose (30mg/kg) after one hour and those which received 1.0x10¹⁰CFU/mL inoculums were treated immediately with three doses of meropenem 50 mg/kg. Outcomes were observed for 24 hours after inoculation.

Results

Solutions with 1.5 x10⁹ and 6.0x10⁹ CFU/mL were not lethal within 24 hours. Inoculums of 1.0x10¹⁰CFU/mL were lethal in 80% and solutions with 2.0x10¹⁰ CFU/mL were lethal in 100% of animals. ESBL lethal sepsis (1.0x10¹⁰CFU/mL) was treated immediately with 50 mg/kg of meropenem every eight hours for 24 hours and presented 40% mortality compared with 80% mortality of the control group (p=0.033). Quantitative cultures of peritoneal fluid presented 10⁴CFU/mL or less for treated animals compared to more than 10⁵ for untreated animals (p=0.001).

Conclusion

Inoculums of 1.0x10¹⁰CFU/mL achieved the best results to study a model of lethal sepsis and this model of treatment of carbapenem-susceptible Enterobacteriaceae can serve as control to further evaluation of treatment of carbapenemase-producing Enterobacteriaceae models.     

3D Assessment of Cortical Bone Porosity and Tissue Mineral Density Using High‐Resolution µCT: Effects of Resolution and Threshold Method

Current micro–computed tomography (µCT) systems allow scanning bone at resolutions capable of three‐dimensional (3D) characterization of intracortical vascular porosity and osteocyte lacunae. However, the scanning and reconstruction parameters along with the image segmentation method affect the accuracy of the measurements. In this study, the effects of scanning resolution and image threshold method in quantifying small features of cortical bone (vascular porosity, vascular canal diameter and separation, lacunar porosity and density, and tissue mineral density) were analyzed. Cortical bone from the tibia of Sprague‐Dawley rats was scanned at 1‐µm and 4‐µm resolution, reconstructions were density‐calibrated, and volumes of interest were segmented using approaches based on edge‐detection or histogram analysis. In 1‐µm resolution scans, the osteocyte lacunar spaces could be visualized, and it was possible to separate the lacunar porosity from the vascular porosity. At 4‐µm resolution, the vascular porosity and vascular canal diameter were underestimated, and osteocyte lacunae were not effectively detected, whereas the vascular canal separation and tissue mineral density were overestimated compared to 1‐µm resolution. Resolution had a much greater effect on the measurements than did threshold method, showing partial volume effects at resolutions coarser than 2 µm in two separate analyses, one of which assessed the effect of resolution on an object of known size with similar architecture to a vascular pore. Although there was little difference when using the edge‐detection versus histogram‐based threshold approaches, edge‐detection was somewhat more effective in delineating canal architecture at finer resolutions (1–2 µm). In addition, use of a high‐resolution (1 µm) density‐based threshold on lower resolution (4 µm) density‐calibrated images was not effective in improving the lower‐resolution measurements. In conclusion, if measuring cortical vascular microarchitecture, especially in small animals, a µCT resolution of 1 to 2 µm is appropriate, whereas a resolution of at least 1 µm is necessary when assessing osteocyte lacunar porosity. © 2014 American Society for Bone and Mineral Research.     

Delayed presentation of deep penetrating trauma to the subaxial cervical spine

Purpose

To present a rare case of deep penetrating neck trauma in which a retained foreign body in the cervical spine (a broken knife blade) resulted in delayed radicular injury. We describe the surgical management using a retrojugular approach.

Case report

Our patient sustained a stab wound to the supraclavicular triangle from a small pocketknife. He was initially managed in a local hospital by simple primary wound closure without any radiological examinations, and was discharged home. The patient re-consulted in a delayed fashion with mild local persistent neck pain. Subsequent radiological investigations revealed a foreign body (the broken blade of a pocket knife) embedded in the left neural foramen between the C6 and C7 vertebrae penetrating the disc space. The blade was lying between the left C7 nerve root and the ipsilateral vertebral artery (VA) at the transition of V1 and V2 segments. Initial neurological evaluation was normal. Some days later, the patient developed a delayed left C7 radicular deficit. We undertook urgent exploration along the wound corridor through a retrojugular, transforaminal approach with successful removal of the blade.

Discussion

To our knowledge, this is a unique case where a retained foreign body penetrated the soft tissues of the neck, embedding deep in the vertebral column without vascular, aerodigestive or significant primary neurological injury, while causing delayed neck pain and delayed onset radicular injury. We describe our surgical management for removal of the retained blade. The retrojugular approach gives excellent access to all of the important anatomical structures of the neck from an anterolateral approach.

     

Efficacy of intralesional recombinant human epidermal growth factor in diabetic foot ulcers in Mexican patients: A randomized double‐blinded controlled trial

The healing process in diabetic foot ulcer (DFU) is hindered by factors such as chronic inflammation, defects in fibroblast function, poor angiogenesis, and lack of cell migration. Recombinant human epidermal growth factor (rhEGF) has been shown to enhance extracellular matrix formation, cellular proliferation, and angiogenesis. Therefore, intralesional application of rhEGF in DFU could accelerate wound healing. Our objective was to determine the efficacy and safety of rhEGF in patients with DFU. A randomized, double‐blinded, placebo‐controlled study was conducted comparing a thrice‐per‐week intralesional application of rhEGF (75 μg) or placebo in patients with DFU for 8 weeks. The number of completely healed ulcers, size, and wound bed characteristics were evaluated to determine the efficacy of rhEGF. Adverse events were recorded and analyzed to establish its safety. A total of 34 patients were recruited for the study. After three dropouts, we were able to follow and analyze 16 patients in the placebo group and 15 patients in the rhEGF study to the end of the trial. Baseline testing showed that both groups were similar. Compared to the placebo group, more ulcers achieved complete healing in the rhEGF group (rhEGF, n = 4; placebo, n = 0; p = 0.033); ulcers in the rhEGF group decreased in area size (12.5 cm2 [rhEGF] vs. 5.2 cm2 [placebo]; p = 0.049); and more epithelial islands in the wound bed were present (28% vs. 3%; p = 0.025). Mild transitory dizziness was the only side effect that was more frequently noted in the rhEGF group. Our results showed that in patients with DFU who received standard care, intralesional rhEGF application resulted in complete healing in more patients, promoted the epithelialization of the wound bed, and significantly reduced the area of the DFU treated. Therefore, rhEGF resulted in better outcomes for patients suffering from DFU.     

The Brazilian Founder Mutation TP53 p.R337H is Uncommon in Portuguese Women Diagnosed with Breast Cancer

Since the first studies reporting the TP53 p.R337H mutation as founder mutation in Southern and Southeastern Brazil, there has been controversy on its origin. Preliminary analysis of a small subset of Brazilian mutation carriers revealed that the haplotype incided on a Caucasian background. The vast majority of carriers identified today reside in Brazil or, if identified in other countries, are Brazilian immigrants. To our knowledge, the only two exceptions of carriers without a recognizable link with Brazil are two European families, from Portugal and Germany. Haplotype analysis in the Portuguese family revealed the same haplotype identified in Brazilian individuals, but in the German family, a distinct haplotype was found. Knowing that a significant proportion of women with breast cancer (BC) in Southern Brazil are p.R337H carriers, we analyzed p.R337H in a Portuguese cohort of women diagnosed with this disease. Median age at diagnosis among the first 573 patients tested was 60 years and 100 (17.4%) patients had been diagnosed at or under the age of 45 years. Mutation screening failed to identify the mutation in the 573 patients tested. These results are in contrast with the mutation frequency observed in a study including 815 BC‐affected women from Brazil, in which carrier frequencies of 12.1 and 5.1% in pre‐ and postmenopausal women were observed, respectively. These findings suggest that the Brazilian founder mutation p.R337H, the most frequent germline TP53 mutation reported to date, is not a common germline alteration in Portuguese women diagnosed with BC.     

Applications of positron emission tomography in neuro-oncology: A clinical approach

The field of neuro-oncology is concerned with some of the most challenging and difficult to treat conditions in medicine. Despite modern therapies patients diagnosed with primary brain tumours often have a poor prognosis. Imaging can play an important role in evaluating the disease status of such patients. In addition to the structural information derived from MRI and CT scans, positron emission tomography (PET) provides important quantitative metabolic assessment of brain tumours. This review describes the use of PET with radiolabelled glucose and amino acid analogues to aid in the diagnosis of tumours, differentiate between recurrent tumour and radiation necrosis and guide biopsy or treatment. [¹⁸F]Fluorodeoxyglucose (FDG) is the tracer that has been used most widely because it has a 2 h half life and can be transported to imaging centres remote from the cyclotron and radiochemistry facilities which synthesise the tracers. The high uptake of FDG in normal grey matter however limits its use in some low grade tumours which may not be visualised. [¹¹C] methionine (MET) is an amino acid tracer with low accumulation in normal brain which can detect low grade gliomas, but its short 20 min half life has limited its use to imaging sites with their own cyclotron. The emergence of new fluorinated amino acid tracers like [¹⁸F]Fluoroethyl-l-tyrosine (FET) will likely increase the availability and utility of PET for patients with primary brain tumours. PET can, further, characterise brain tumours by investigating other metabolic processes such as DNA synthesis or thymidine kinase activity, phospholipid membrane biosynthesis, hypoxia, receptor binding and oxygen metabolism and blood flow, which will be important in the future assessment of targeted therapy.     

Do stand-alone interbody spacers with integrated screws provide adequate segmental stability for multilevel cervical arthrodesis?

Background contextSome postoperative complications after anterior cervical fusions have been attributed to anterior cervical plate (ACP) profiles and the necessary wide operative exposure for their insertion. Consequently, low-profile stand-alone interbody spacers with integrated screws (SIS) have been developed. Although SIS constructs have demonstrated similar biomechanical stability to the ACP in single-level fusions, their role as a stand-alone device in multilevel reconstructions has not been thoroughly evaluated.PurposeTo evaluate the acute segmental stability afforded by an SIS device compared with the traditional ACP in the setting of a multilevel cervical arthrodesis.Study designIn vitro human cadaveric biomechanical analysis.MethodsThirteen human cadaveric cervical spines (C2–T1) were nondestructively tested with a custom 6 df spine simulator under axial rotation, flexion-extension, and lateral bending loading. After intact analysis, eight single-levels (C4–C5/C6–C7) from four specimens were instrumented and tested with ACP and SIS. Nine specimens were tested with C5–C7 SIS, C5–C7 ACP, C4–C7 ACP, C4–C7 ACP+posterior fixation, C4–C7 SIS, and C4–C7 SIS+posterior fixation. Testing order was randomized with each additional level instrumented. Full range of motion (ROM) data were obtained and analyzed by each loading modality, using mean comparisons with repeated measures analysis of variance. Paired t tests were used for post hoc analysis with Sidak correction for multiple comparisons.ResultsNo significant difference in ROM was noted between the ACP and SIS for single-level fixation (p>.05). For multisegment reconstructions (two and three levels), the ACP proved superior to SIS and intact condition, with significantly lower ROM in all planes (p<.05). When either the three-level SIS or ACP constructs were supplemented with posterior lateral mass fixation, there was a greater than 80% reduction in ROM under all testing modalities (p<.05), with no significant difference between the ACP and SIS constructs (p>.05).ConclusionsThe SIS device may be a reasonable option as a stand-alone device for single-level fixation. However, SIS devices should be used with careful consideration in the setting of multilevel cervical fusion. However, when supplemented with posterior fixation, SIS devices are a sound biomechanical alternative to ACP for multilevel fusion constructs.     

The Integration of Studio Cycling into a Worksite Stress Management Programme

High stress is a prevalent problem in the worksite. To reduce stress, improve productivity, reduce absenteeism, and lower healthcare costs, many companies offer exercise classes or stress management programmes. Although physical activity is an important component of stress management, few worksites have integrated physical activity into their comprehensive stress reduction programmes. The purpose of this single‐arm pilot project was to examine the potential effectiveness of an integrated exercise (studio cycling) and cognitive–behavioural stress management programme. Eighty‐four adults, 75% female, mostly aged 40+ years, participated in an integrated 12‐week cycling studio and cognitive–behavioural stress management programme. Participants experienced a significant and clinically meaningful reduction on the Perceived Stress Scale (p < 0.01), rating of current stress level and confidence to manage stress at the programme's end and at a 1‐month follow‐up. Participants also reported having significantly improved overall health, improved nutritional habits, higher physical activity level, greater confidence in their ability to follow a healthy diet, higher spiritual well‐being, improved sleep, receiving more support for maintaining healthy living and improved quality of life at the completion of the 12‐week programme and 1‐month follow‐up. These findings provide further support for an integrated exercise and stress management programme. Copyright © 2013 John Wiley & Sons, Ltd.     

Impact of prior chronic statin therapy and high-intensity statin therapy at discharge on circulating endothelial progenitor cell levels in patients with acute myocardial infarction: a prospective observational study

Background

Endothelial progenitor stem cells (EPCs) are mobilized to the peripheral circulation in response to myocardial ischemia, playing a crucial role in vascular repair. Statins have been shown to stimulate EPCs. However, neither the impact of previous statin therapy on EPC response of acute myocardial infarction (AMI) patients nor the effect of post-AMI high-intensity statin therapy on the evolution of circulating EPC levels has yet been addressed. Therefore, we aimed to compare circulating EPC levels between patients receiving long-term statin therapy before the AMI and statin-naive patients and to assess the impact of high-intensity statin therapy at discharge on the evolution of circulating EPCs post-AMI.

Methods

This is a prospective observational study of 100 AMI patients. Circulating EPCs (CD45dimCD34?+?KDR?+?cells) and their subpopulation coexpressing the homing marker CXCR4 were quantified by the high-performance flow cytometer FACSCanto II in whole blood, in two different moments: within the first 24 h of admission and 3 months post-AMI. Patients were followed up clinically for 2 years.

Results

Patients previously treated with statins had significantly higher levels of EPCs coexpressing CXCR4 (1.9?±?1.4 vs. 1.3?±?1.0 cells/1,000,000 events, p?=?0.031) than statin-naive patients. In addition, the subanalysis of diabetics (N?=?38) also revealed that patients previously on statins had significantly greater numbers of both CD45dimCD34?+?KDR?+?CXCR4+ cells (p?=?0.024) and CD45dimCD34?+?KDR?+?CD133+ cells (p?=?0.022) than statin-naive patients. Regarding the evolution of EPC levels after the AMI, patients not on a high-intensity statin therapy at discharge had a significant reduction of CD45dimCD34?+?KDR?+?and CD45dimCD34?+?KDR?+?CXCR4+ cells from baseline to 3 months follow-up (p?=?0.031 and p?=?0.005, respectively). However, patients discharged on a high-intensity statin therapy maintained circulating levels of all EPC populations, presenting at 3 months of follow-up significantly higher EPC levels than patients not on an intensive statin therapy. Moreover, the high-intensity statin treatment group had significantly better clinical outcomes during the 2-year follow-up period than patients not discharged on a high-intensity statin therapy.

Conclusion

Chronic statin therapy prior to an AMI strongly enhances the response of EPCs to myocardial ischemia, even in diabetic patients. Furthermore, high-intensity statin therapy after an AMI prevents the expected decrease of circulating EPC levels during follow-up. These results reinforce the importance of an early and intensive statin therapy in AMI patients.