Induction Implications: Shaping the Competence and Confidence of Junior Doctors Within Complex Medical Specialties.

Introduction The newly qualified junior doctors in the United Kingdom face challenges due to their limited experience and unfamiliarity with their rotations. We aim to share the experience of establishing a hepato-pancreato-biliary (HPB) surgery-specific induction program at the University Hospitals of Leicester NHS Trust and assess its impact on doctors' knowledge and experience. Methods A booklet was distributed to new junior doctors, and a two-hour structured teaching session was also conducted, with pre- and post-session assessments using multiple-choice questions and a feedback survey. The survey measured understanding of HPB anatomy, interventions, and satisfaction with the teaching methodology. Results The pre-session questionnaire included 22 participants, while the post-session had 20 participants. Regarding HPB anatomy understanding, in the pre-session, six (28.6%) and 11 (52.4%) participants reported levels 2 and 3, respectively, while levels 4 and 5 were reported by three (13.3%) and one (4.8%) participants. In the post-session, levels 4 and 5 were reported by six (30%) and 13 (65%), with only one (5%) reporting level 3 and none at levels 1 or 2. Similar trends were observed in understanding HPB investigation. In the pre-session, levels 2 and 3 were reported by eight (36.4%) and 11 (50%), while levels 4 and 5 were reported by two (9.1%) and one (4%). In the post-session, eight (40%) and 11 (55%) reported levels 4 and 5, with only one (5%) at level 3 and none at levels 1 or 2. For HPB management methods before teaching, levels 2 and 3 were equally reported by eight (36.4%), level 4 by four (22.7%), and none at level 5. After teaching, nine (45%) and 10 (50%) reported levels 4 and 5, with only one (5%) at level 3 and none at levels 1 or 2. Factual knowledge showed a 38% increase, rising from 49% pre-session to 87% post-session. In post-session feedback, 12 (60%) strongly agreed that the session helped augment their medical practice, and six (30%) agreed, with two (10%) neutral. Feedback on the teaching session's organization was positive, with 13 (65%) strongly agreeing that it was structured coherently, and six (30%) agreeing, with only one (5%) neutral regarding the clarity of the structure and delivery method. Conclusion Specialty-specific induction programs are crucial for providing support and ensuring the development of competent doctors. Efforts should be made to create supportive working environments for junior doctors to alleviate stress and improve their well-being.

Randomized Trial of Bupivacaine Versus Liposomal Bupivacaine in Minimally Invasive Lobectomy.

BACKGROUND: The objective of this single-blind randomized study is to compare local infiltration of bupivacaine or liposomal bupivacaine (LipoB) in narcotic naïve patients undergoing minimally invasive lobectomy for early stage lung cancer. METHODS: Adult patients without previous lung surgery undergoing minimally invasive lobectomy (robotic or thoracoscopic) for early stage lung cancer were randomly assigned to bupivacaine (with epinephrine 0.25%, 1:200 000) or LipoB 1.3%. Pain level was documented using the visual analog scale and morphine equivalents for narcotic pain medications. Inhospital treatment cost and pharmacy cost were compared. RESULTS: The study enrolled 50 patients (bupivacaine, 24; LipoB, 26). The mean age of patients was 66 years, 94% were non-Hispanic white, and 48% were male. There was no difference in baseline characteristics and comorbidities. Duration of surgery (105 vs 137 minutes, P = .152), chest tube duration (49 vs 55 hours, P = .126), and length of stay (2.45 vs 3.28 days, P = .326) were similar between treatments. Inhospital morphine equivalents were 42.7 mg vs 48 mg (P = .714), and the median pain score was 5.2 vs 4.75 (P = .602) for bupivacaine vs LipoB, respectively. There was no difference in narcotic use at 2 to 4 weeks (57.1% [12 of 21] vs 54.5% [12 of 22], P = 1.00), and at 6 months (5.9% [1 of 17] vs 9.5% [2 of 21], P = 1.00) after surgery. The overall cost ($20 252 vs $22 775, P = .225) was similar; however, pharmacy cost for LipoB was higher ($1052 vs $596, P = .0001). CONCLUSIONS: In narcotic naïve patients undergoing minimally invasive lobectomy, short-term narcotic use, postoperative pain scores, length of stay, and long-term narcotic use were similar between bupivacaine and LipoB.

Proposed clinical internal carotid artery classification system.

INTRODUCTION: Numerical classification systems for the internal carotid artery (ICA) are available, but modifications have added confusion to the numerical systems. Furthermore, previous classifications may not be applicable uniformly to microsurgical and endoscopic procedures. The purpose of this study was to develop a clinically useful classification system. MATERIALS AND METHODS: We performed cadaver dissections of the ICA in 5 heads (10 sides) and evaluated 648 internal carotid arteries with computed tomography angiography. We identified specific anatomic landmarks to define the beginning and end of each ICA segment. RESULTS: The ICA was classified into eight segments based on the cadaver and imaging findings: (1) Cervical segment; (2) cochlear segment (ascending segment of the ICA in the temporal bone) (relation of the start of this segment to the base of the styloid process: Above, 425 sides [80%]; below, 2 sides [0.4%]; at same level, 107 sides [20%]; P < 0.0001) (relation of cochlea to ICA: Posterior, 501 sides [85%]; posteromedial, 84 sides [14%]; P < 0.0001); (3) petrous segment (horizontal segment of ICA in the temporal bone) starting at the crossing of the eustachian tube superolateral to the ICA turn in all 10 samples; (4) Gasserian-Clival segment (ascending segment of ICA in the cavernous sinus) starting at the petrolingual ligament (PLL) (relation to vidian canal on imaging: At same level, 360 sides [63%]; below, 154 sides [27%]; above, 53 sides [9%]; P < 0.0001); in this segment, the ICA projected medially toward the clivus in 275 sides (52%) or parallel to the clivus with no deviation in 256 sides (48%; P < 0.0001); (5) sellar segment (medial loop of ICA in the cavernous sinus) starting at the takeoff of the meningeal hypophyseal trunk (ICA was medial into the sella in 271 cases [46%], lateral without touching the sella in 127 cases [23%], and abutting the sella in 182 cases [31%]; P < 0.0001); (6) sphenoid segment (lateral loop of ICA within the cavernous sinus) starting at the crossing of the fourth cranial nerve on the lateral aspect of the cavernous ICA and located directly lateral to the sphenoid sinus; (7) ring segment (ICA between the 2 dural rings) starting at the crossing of the third cranial nerve on the lateral aspect of the ICA; (8) cisternal segment starting at the distal dural ring. CONCLUSIONS: The classification may be applied uniformly to all skull base surgical approaches including lateral microsurgical and ventral endoscopic approaches, obviating the need for 2 separate classification systems. The classification allows extrapolation of relevant clinical information because each named segment may indicate potential surgical risk to specific structures.

Oncometabolomics in cancer research.

Cancer is not only a complex genetic disease, but also a disease of dysregulated bioenergetic metabolism. With improved technological advancements, the focus has shifted from changes in an individual biochemical pathway or metabolite toward changes in the context of the global network of metabolic pathways in a cell, tissue or organism. This global approach allows identifying changes in the pattern of metabolite expression in addition to changes in individual metabolite or pathway. Such a metabolomics approach promises a better understanding of tumor biology and identification of potential biomarkers with applications as diagnostic, prognostic and therapeutic targets. In this review, we discuss various techniques used in metabolomics and analysis of the data generated and its specific uses in cancer research including novel biomarker identification, development of more sensitive and specific diagnostic methods, monitoring of currently used cancer therapeutics to evaluate the prognostic outcome with a given therapy and evaluating novel therapeutic strategies.

Surfactant-free synthesis of biodegradable, biocompatible, and stimuli-responsive cationic nanogel particles.

Nanogels have attracted much attention lately because of their many potential applications, including as nanocarriers for drug and gene delivery. Most nanogels reported previously, however, are not biodegradable, and their synthesis often requires the use of surfactants. Herein we report a surfactant-free method for the preparation of biodegradable, biocompatible, and stimuli-responsive cationic nanogels. The nanogels were synthesized by simply coaservating linear polymer precursors in mixed solvents followed by in situ cross-linking with homobifunctional cross-linkers. The versatility of this approach has been demonstrated by employing two different polymers and various cross-linkers to prepare nanogel particles with diameters ranging from 170 to 220 nm. Specifically, disulfide-containing tetralysine (TetK)- and oligoethylenimine (OEI)-based prepolymers were prepared and the subsequent nanogels were formed by covalently cross-linking the polymer coacervate phase. Nanogel particles are responsive to pH changes, increasing in size and zeta-potential with concomitant lowering of solution pH. Furthermore, as revealed by AFM imaging, nanogel particles were degradable in the presence of glutathione at concentrations similar to those in intracellular environment (10 mM). Both the nanogel and the polymer precursors were determined to exhibit minimal cytotoxicity against fibroblast 3T3 cells by flow cytometric analyses and fluorescent imaging. This study demonstrates a new surfactant-free method for preparing biodegradable, biocompatible, and stimuli-responsive nanogels as potential nanocarriers for the delivery of drugs and genes.

Modulation of chondrocyte behavior through tailoring functional synthetic saccharide-peptide hydrogels.

Tailoring three-dimensional (3D) biomaterial environments to provide specific cues in order to modulate function of encapsulated cells could potentially eliminate the need for addition of exogenous cues in cartilage tissue engineering. We recently developed saccharide-peptide copolymer hydrogels for cell culture and tissue engineering applications. In this study, we aim to tailor our saccharide-peptide hydrogel for encapsulating and culturing chondrocytes in 3D and examine the effects of changing single amino acid moieties differing in hydrophobicity/hydrophilicity (valine (V), cysteine (C), tyrosine (Y)) on modulation of chondrocyte function. Encapsulated chondrocytes remained viable over 21 days in vitro. Glycosaminoglycan and collagen content was significantly higher in Y-functionalized hydrogels compared to V-functionalized hydrogels. Extensive matrix accumulation and concomitant increase in mechanical properties was evident over time, particularly with the presence of Y amino acid. After 21 days in vitro, Y-functionalized hydrogels attained a modulus of 193 ± 46 kPa, compared to 44 ± 21 kPa for V-functionalized hydrogels. Remarkably, mechanical and biochemical properties of chondrocyte-laden hydrogels were modulated by change in a single amino acid moiety. This unique property, combined with the versatility and biocompatibility, makes our saccharide-peptide hydrogels promising candidates for further investigation of combinatorial effects of multiple functional groups on controlling chondrocyte and other cellular function and behavior.

Biodegradable and biocompatible synthetic saccharide-Peptide hydrogels for three-dimensional stem cell culture.

Saccharide-peptide hydrogels have been developed in our laboratory as new synthetic extracellular matrices for regenerative medicine applications. In this work, we have expanded on our previously reported system and applied copolymerization of cysteine (Cys) and vinyl sulfone (VS)-functionalized saccharide-peptide polymers via Michael-type addition for encapsulation and 3D culture of cells. Specifically, our aims were to (1) develop a novel hydrogel platform, which could be applied for encapsulating and culturing mesenchymal stem cells (MSCs) in a 3D environment, (2) characterize the tunable properties of the hydrogel, specifically, degradation, mechanical, and gel network properties, and (3) determine the biocompatibility of the saccharide-peptide hydrogel material with MSCs. Hydrogel mechanical properties were tunable by varying the VS:Cys ratio (= 0.5, 1, or 2) as well as the pH (6, 7, or 8) of the cross-linking components. Stiffer gels were formed at VS:Cys = 1 and pH 6 or 7. Gels formed at pH 8 or with excess Cys (VS:Cys = 0.5) or VS (VS:Cys = 2) were significantly softer. Cross-linking pH and VS:Cys ratio also had an effect on the degradation behavior of the VS:Cys gels, with higher cross-linking pH resulting in an accelerated loss of mass. On the basis of environmental scanning electron microscopy (ESEM) analysis and fluorescence microscopy, all hydrogels appeared to exhibit porous gel networks. MSCs cultured in monolayer and exposed to soluble Cys or VS copolymers (0.1-5 mg/mL) did not exhibit measurable cytotoxicity. In addition, MSCs were cultured in 3D for up to 14 days in vitro without deleterious effects on cell viability. In summary, we have established and characterized a tunable 3D saccharide-peptide hybrid copolymer hydrogel platform for culturing MSCs. Future studies will focus on utilizing the hydrogel system for controlling the differentiation of MSCs.

Tracking chondrocytes and assessing their proliferation with carboxyfluorescein diacetate succinimidyl ester: effects on cell functions.

Distinguishing between implanted and host-derived cells, as well as cells of different phenotypes, is important in determining mechanisms of cell-based repair of cartilage. The objectives of this study were to assess the utility of carboxyfluorescein diacetate, succinimidyl ester ("CFDA, SE" or CFSE) for tracking chondrocytes from superficial (S) and middle (M) zones and their proliferation, and to determine the effects of CFSE on the chondrocyte functions, proliferation, and synthesis of proteoglycan 4 (PRG4) and glycosaminoglycan (GAG). CFSE-labeled and unlabeled S and M zone chondrocytes were plated in either low- or high-density (10,000 or 200,000 cells/cm(2)) monolayer, incubated, and analyzed on days 1 and 7. Cell suspensions were analyzed for retention of CFSE by flow cytometry and fluorescence microscopy and for cell proliferation by assay for DNA and GAG. Cultures were also analyzed for newly synthesized PRG4. Deconvolution of flow cytometric histograms was done to determine the number of cells in each doubling generation. Most chondrocytes were labeled consistently and intensely labeled with CFSE through 10 cycles of division. At day 7 of culture, approximately 95% of S and M zone cells seeded at high density could be distinguished as fluorescent. Chondrocyte proliferation and synthesis of PRG4 were unaffected by cell labeling, while GAG synthesis was slightly diminished. CFSE may be useful in determining the fate and function of implanted chondrocytes in vivo.

A novel low-friction surface for biomedical applications: modification of poly(dimethylsiloxane) (PDMS) with polyethylene glycol(PEG)-DOPA-lysine.

Aqueous biocompatible tribosystems are desirable for a variety of tissue-contacting medical devices. L-3,4-dihydroxyphenylalanine (DOPA) and lysine (K) peptide mimics of mussel adhesive proteins strongly interact with surfaces and may be useful for surface attachment of lubricating polymers in tribosystems. Here, we describe a significant improvement in lubrication properties of poly (dimethylsiloxane) (PDMS) surfaces when modified with PEG-DOPA-K. Surfaces were characterized by optical and atomic force microscopy, contact angle, PM-IRRAS, and X-ray photoelectron spectroscopy. Such surfaces, tested over the course of 200 rotations ( approximately 8 m in length), maintained an extremely low friction coefficient (mu) (0.03 +/- 0.00) compared to bare PDMS (0.98 +/- 0.02). These results indicate the potential applications of PEG-DOPA-K for the modification of device surfaces. Extremely low mu values were maintained over relatively long length scales and a range of sliding speeds without the need for substrate pre-activation and in the absence of excess polymer in aqueous solution. These results were only obtained when DOPA was bound to lysine (modification with PEG-DOPA did not have an effect on mu) suggesting the critical role of lysine in obtaining a lowered friction coefficient.

Short-term retention of labeled chondrocyte subpopulations in stratified tissue-engineered cartilaginous constructs implanted in vivo in mini-pigs.

It is likely that effective application of cell-laden implants for cartilage defects depends on retention of implanted cells and interaction between implanted and host cells. The objectives of this study were to characterize stratified cartilaginous constructs seeded sequentially with superficial (S) and middle (M) chondrocyte subpopulations labeled with fluorescent cell tracking dye PKH26 (*) and determine the degree to which these stratified cartilaginous constructs maintain their architecture in vivo after implantation in mini-pigs for 1 week. Alginate-recovered cells were seeded sequentially to form stratified S*/M (only S cells labeled) and S*/M* (both S and M cells labeled) constructs. Full-thickness defects (4 mm diameter) were created in the patellofemoral groove of adult Yucatan mini-pigs and filled with portions of constructs or left empty. Constructs were characterized biochemically, histologically, and biomechanically, and stratification visualized and quantified, before and after implant. After 1 week, animals were sacrificed and implants retrieved. After 1 week in vivo, glycosaminoglycan and collagen content of constructs remained similar to that at implant, whereas DNA content increased. Histological analyses revealed features of an early repair response, with defects filled with tissues containing little matrix and abundant cells. Some implanted (PKH26-labeled) cells persisted in the defects, although constructs did not maintain a stratified organization. Of the labeled cells, 126 +/- 38% and 32 +/- 8% in S*/M and S*/M* constructs, respectively, were recovered. Distribution of labeled cells indicated interactions between implanted and host cells. Longer-term in vivo studies will be useful in determining whether implanted cells are sufficient to have a positive effect in repair.

Tracking chondrocytes and assessing their proliferation with PKH26: effects on secretion of proteoglycan 4 (PRG4).

Distinguishing between implanted and host-derived cells, as well as between distinct cell phenotypes, would be useful in assessing the mechanisms of cell-based repair of cartilage. The fluorescent tracker dye, PKH26, was previously applied to several cell types to assess proliferation in vitro and to track cells in vivo. The objectives of this study were to assess the utility of PKH26 for tracking chondrocytes from superficial and middle zones and their proliferation, and determine the effects of PKH26 on chondrocyte functions, in particular, proliferation and secretion of Proteoglycan 4 (PRG4). PKH26-labeled and unlabeled superficial and middle zone chondrocytes were plated in either low- or high-density monolayer culture and analyzed for retention of PKH26 by flow cytometry and fluorescence microscopy at days 0 and 7. Cell suspensions and conditioned media were analyzed for DNA and secretion of PRG4, respectively. Flow cytometric histograms were deconvolved so that the number of cells in each doubling generation contributing to the final cell population could be estimated. Chondrocytes were consistently and intensely labeled with PKH26 through 7 cycles of division. At day 7 of culture, >97% of superficial zone cells seeded at low or high density could be distinguished as fluorescent, as could middle zone cells seeded at high density. Retention of cell fluorescence after PKH26 labeling and lack of adverse effects on cell proliferation and synthesis of PRG4 suggest that PKH26 can be useful in determining the fate and function of implanted chondrocytes in vivo, as well as monitoring proliferation in vitro.

In vitro physical stimulation of tissue-engineered and native cartilage.

Because of the limited availability of donor cartilage for resurfacing defects in articular surfaces, there is tremendous interest in the in vitro bioengineering of cartilage replacements for clinical applications. However, attaining mechanical properties in engineered cartilaginous constructs that approach those of native cartilage has not been previously achieved when constructs are cultured under free-swelling conditions. One approach toward stimulating the development of constructs that are mechanically more robust is to expose them to physical environments that are similar, in certain ways, to those encountered by native cartilage. This is a strategy motivated by observations in numerous short-term experiments that certain mechanical signals are potent stimulators of cartilage metabolism. On the other hand, excess mechanical loading can have a deleterious effect on cartilage. Culture conditions that include a physical stimulation component are made possible by the use of specialized bioreactors. This chapter addresses some of the issues involved in using bioreactors as integral components of cartilage tissue engineering and in studying the physical regulation of cartilage. We first consider the generation of cartilaginous constructs in vitro. Next we describe the rationale and design of bioreactors that can impart either mechanical deformation or fluid-induced mechanical signals.