Endoscopic ultrasound-guided fine-needle aspiration cytology of peripheral nerve-sheath tumors

Endoscopic ultrasound (EUS) has allowed for the fine-needle aspiration and diagnosis of many different gastrointestinal neoplasms, including mesenchymal tumors. Although most mesenchymal tumors of the gastrointestinal tract are gastrointestinal stromal tumors (GISTs), other mesenchymal tumors, including neural tumors, do occur. Proper diagnosis and differentiation of these tumors from GISTs are important because of their different prognoses and treatment regimens. We encountered three peripheral nerve-sheath tumors of the gastrointestinal tract aspirated by EUS (two schwannomas and a granular-cell tumor). We report on the endoscopic ultrasound, cytologic, histologic, and immunohistochemical findings of these cases.     

Chondroconductive potential of tantalum trabecular metal

Mesenchymal stem cells or chondrocytes have been implanted into joints in biodegradable matrices in order to improve the quality of healing cartilage defects; however, insufficient biomechanical strength of the construct at implantation is a limiting factor for clinical application. Logically, a construct with better biomechanical characteristics would provide better results. Tantalum trabecular metal (TTM) is osteoconductive and mechanically similar to subchondral bone. The objective of this pilot study was to determine if TTM is also chondroconductive. Small sections of TTM were cultured with emu and canine chondrocytes in static and dynamic culture environments. The sections cultured in dynamic bioreactors were diffusely covered with a cartilaginous matrix. Sections cultured in static conditions had no growth. Histologic evaluation from emu and canine dynamic cultures showed tissue that was heavily populated with mesenchymal cells that resembled chondrocytes, and glycosaminoglycan staining that was distributed throughout the matrix. Type II collagen content in the canine dynamic culture was 84% by SDS-PAGE. Tantalum trabecular metal is chondroconductive in vitro in a dynamic environment when cultured with adult canine or emu chondrocytes. This technology could be expanded to determine if cartilaginous-metallic constructs may be used for joint resurfacing of osteoarthritic joints.     

Lung preservation solution substrate composition affects rat lung oxidative metabolism during hypothermic storage

Lungs harvested for transplantation utilize oxygen after procurement. We investigated the effects of storage solution substrate composition on pulmonary oxidative metabolism and energetics during the preservation interval. Rat lungs were harvested and stored at 10 degrees C in low-potassium dextran (LPD) solution. Groups of lungs were preserved with preservation solution containing 5mM carbon-13 ((13)C) labeled glucose or increasing concentrations of (13)C labeled pyruvate. Additional groups of rat lungs were studied with dichloroacetate (DCA) added to the pyruvate-modified preservation solutions. Oxidative metabolism (measured by (13)C-enrichment of glutamate) and adenine nucleotide levels were quantified. Increasing preservation solution pyruvate concentration augmented glutamate (13)C-enrichment up to a concentration of 32mM pyruvate. DCA further stimulated oxidative metabolism only at lower concentrations of pyruvate (4 and 8mM). ATP and ADP were not different among groups, but AMP levels were higher in the glucose group. These data suggest that altering the substrate composition of the preservation solution influences lung metabolism during allograft preservation for transplantation.     

Antibiotic susceptabilities of Pseudomonas aeruginosa isolates derived from patients with cystic fibrosis under aerobic, anaerobic, and biofilm conditions

Recent studies have determined that Pseudomonas aeruginosa can live in a biofilm mode within hypoxic mucus in the airways of patients with cystic fibrosis (CF). P. aeruginosa grown under anaerobic and biofilm conditions may better approximate in vivo growth conditions in the CF airways, and combination antibiotic susceptibility testing of anaerobically and biofilm-grown isolates may be more relevant than traditional susceptibility testing under planktonic aerobic conditions. We tested 16 multidrug-resistant isolates of P. aeruginosa derived from CF patients using multiple combination bactericidal testing to compare the efficacies of double and triple antibiotic combinations against the isolates grown under traditional aerobic planktonic conditions, in planktonic anaerobic conditions, and in biofilm mode. Both anaerobically grown and biofilm-grown bacteria were significantly less susceptible (P < 0.01) to single and combination antibiotics than corresponding aerobic planktonically grown isolates. Furthermore, the antibiotic combinations that were bactericidal under anaerobic conditions were often different from those that were bactericidal against the same organisms grown as biofilms. The most effective combinations under all conditions were colistin (tested at concentrations suitable for nebulization) either alone or in combination with tobramycin (10 microg ml(-1)), followed by meropenem combined with tobramycin or ciprofloxacin. The findings of this study illustrate that antibiotic sensitivities are dependent on culture conditions and highlight the complexities of choosing appropriate combination therapy for multidrug-resistant P. aeruginosa in the CF lung.     

Effects of age and size in the ears of gekkonomorph lizards: middle-ear morphology with evolutionary implications

The function of the ear depends in part on its absolute size and internal proportions. Thus, in both young individuals and small species, the middle ear is expected to be allometrically enlarged despite its smaller absolute size. Here we aim to compare the ontogenetic allometry of relevant middle-ear structures as observed within gecko (gekkonomorph lizards) species, with the evolutionary allometry observed interspecifically. These observations also provide middle-ear data for future evaluation of variation in auditory sensitivity. The material comprised 84 museum specimens of geckos, representing nine species of three gekkonomorph subfamilies. The results of dissections and measurements show that different reports notwithstanding, the middle-ear ossicular chain is indeed structured as described for geckos by Werner and Wever. Some sexual dimorphism is indicated, but this requires further study. During postnatal ontogeny, the allometric growth in the ratio of the columellar footplate area to body length differed between the intraspecific and interspecific levels, hence species differences in the middle ear do not merely result from animal size. The ratio of the tympanic membrane area to the columellar footplate area increased during ontogeny. In this, geckos resemble birds and probably also mammals. Similarly, when the comparison was among adults representing different species, the ratio of the tympanic membrane area to the columellar footplate area increased with body size. In this, however, the geckos differed from birds and mammals, in which this ratio varied taxonomically, irrespective of body size. It would thus seem that middle-ear proportions have evolved among geckos to produce small interspecific differences, but among amniote tetrapods they have evolved according to different principles in the classes reptiles, birds, and mammals.     

Mitigating disparity in children with acute appendicitis: Impact of patient-driven protocols

PurposePrevious reports in the literature demonstrate racial and ethnic disparities for children diagnosed with acute appendicitis, with minorities experiencing worse outcomes. At our institution, we have developed an evidence based patient driven protocol for children following laparoscopic appendectomy. However, the influence of such protocol on mitigating racial and ethnic disparities in outcomes remains unknown. The purpose of our study is to assess the impact of our protocol by evaluating the influence of race and ethnicity on surgical outcomes among children treated for acute appendicitis.Material and methodsA retrospective review of prospectively collected data was conducted. Children undergoing a laparoscopic appendectomy at our freestanding children's hospital between December 2015 and July 2017 were included. Demographic data, post-operative length of stay, same day discharge rates and hospital readmission rates were abstracted from patient medical records. Patients were classified by their race and ethnic background. Comparative analysis was performed in STATA with a p value < .05 determined as significant.ResultsA total of 786 children were included, with the majority being either White (70%, n = 547), Black (8%, n = 62) or Hispanic (17%, n = 133); 569 patients (72%) were found to have non-perforated appendicitis. There was no statistically significant difference in the rates of same day discharge among White, Black or Hispanic children respectively (88% vs. 77% vs. 86%, p = .126). Of the 217 children with perforated appendicitis, Hispanic children had increased rates of perforation (41%, n = 55) compared to White and Black children respectively (23%, n = 128 and 29%, n = 18, p = .001). However, average post-operative length of stay were similar among White, Black and Hispanic children (96 h vs. 95 h vs. 98 h, p = .015). On multivariate analysis, the only significant risk factor for an elevated post-operative length of stay was the presence of a perforation.ConclusionOur evidence based patient driven protocol effectively mitigates racial and ethnic disparities found in children with acute appendicitis. Further prospective investigation into the role of such patient-driven protocols to mitigate healthcare disparities is warranted.Levels of EvidenceTherapeutic study; Level 3.     

A single institution experience with Laparoscopic Hernia repair in 791 children

IntroductionThere are many described technique to performing laparoscopic inguinal hernia repair in children. We describe our outcomes using a percutaneous internal ring suturing technique.MethodsA retrospective review of patients under 18 years old who underwent repair between January 2014 - March 2019 was performed. A percutaneous internal ring suturing technique, involving hydro-dissection of the peritoneum, percutaneous suture passage, and cauterization of the peritoneum in the sac prior to high ligation, was used. p < 0.05 was considered significant during the analysis.Results791 patients were included. The median age at operation was 1.9 years (IQR 0.37, 5.82). The median operative time for a unilateral repair was 21 min (IQR 16, 28), while the median time for a bilateral repair was 30.5 min (IQR 23, 41).In total, 3 patients required conversion to an open procedure (0.4%), 4 (0.6%) experienced post-operative bleeding, 9 (1.2%) developed a wound infection, and iatrogenic ascent of testis occurred in 10 (1.3%) patients. Twenty patients (2.5%) developed a recurrent hernia. All but two were re-repaired laparoscopically.ConclusionsThe use of percutaneous internal ring suturing for laparoscopic repair of inguinal hernias in the pediatric population is safe and effective with a low rate of complications and recurrence.