Achromobacter species (sp.) outbreak caused by hospital equipment containing contaminated water: risk factors for infection

BACKGROUND

Nosocomial outbreaks of urinary tract infections caused by Achromobacter spp. have been rare in recent decades.

AIM

To identify the origin of an Achromobacter sp. outbreak, conduct multi-modal infection control measures, and finally to stop the outbreak. To this end, an epidemiological outbreak investigation and risk factor analysis were performed.

METHODS

Achromobacter sp. was detected in 22 patients in our urology wards and six environmental cultures of specimens obtained from the operating rooms. Strains isolated were submitted for antimicrobial susceptibility testing. An on-site epidemiological investigation, evaluation of patient medical records, and environmental sampling were performed to identify the source of the outbreak, and implementation of infection control intervention. A case-control study was performed to analyse the potential risk factors.

FINDINGS

Environmental sampling showed that the source of the infection for 22 patients was an ISA-IIIA-type medical pressurizer containing contaminated water. A case-control analysis showed that the risk factors for infection were: diagnosis of kidney/ureteral stones, surgery, placement of a double-J stent, and history of hospitalization in the past three months.

CONCLUSION

It was concluded that the outbreak occurred in patients who underwent internal lithotripsy and double-J stent placement, due to contact transmission with the contaminated sensor and connecting tubes of the ISA-IIIA-type medical pressurizer.

STAT6 mutations enriched at diffuse large B-cell lymphoma relapse reshape the tumor microenvironment

Diffuse large B-cell lymphoma (DLBCL) relapses in approximately 40% of patients following frontline therapy. We reported that STAT6D419 mutations are enriched in relapsed/refractory DLBCL (rrDLBCL) samples, suggesting that JAK/STAT signaling plays a role in therapeutic resistance. We hypothesized that STAT6D419 mutations can improve DLBCL cell survival by reprogramming the microenvironment to sustain STAT6 activation. Thus, we investigated the role of STAT6D419 mutations on DLBCL cell growth and its microenvironment. We found that phospho-STAT6D419N was retained in the nucleus longer than phospho-STAT6WT following IL-4 stimulation, and STAT6D419N recognized a more restricted DNA-consensus sequence than STAT6WT. Upon IL-4 induction, STAT6D419N expression led to a higher magnitude of gene expression changes, but in a more selective list of gene targets compared with STATWT. The most significantly expressed genes induced by STAT6D419N were those implicated in survival, proliferation, migration, and chemotaxis, in particular CCL17. This chemokine, also known as TARC, attracts helper T-cells to the tumor microenvironment, especially in Hodgkin's lymphoma. To this end, in DLBCL, phospho-STAT6+ rrDLBCL cells had a greater proportion of infiltrating CD4+ T-cells than phospho-STAT6- tumors. Our findings suggest that STAT6D419 mutations in DLBCL lead to cell autonomous changes, enhanced signaling, and altered composition of the tumor microenvironment.

Negative associations of morning serum cortisol levels with obesity: the Henan rural cohort study

AIMS

To evaluate the associations of morning serum cortisol levels with obesity defined by different indices in Chinese rural populations.

MATERIALS AND METHODS

A cross-sectional study was performed including 6198 participants (2566 males and 3632 females). Serum cortisol was collected in morning and quantified by liquid chromatography-tandem mass spectrometry. Obesity was defined by body mass index (BMI), body fat percentage (BFP), waist-to-height ratio (WHtR), waist circumference (WC), visceral fat index (VFI) and waist-to-hip ratio (WHR). Both multivariable liner regression, logistic regression and restrictive cubic splines models were used to estimate the gender-specific relationships between cortisol levels and obesity defined by different indices, respectively.

RESULTS

After adjusting for potential confounders, serum cortisol was negatively associated with different obesity measures, except obese females defined by BFP (for instance, overall obesity defined by BMI, Quartile 4 vs. Quartile 1, odds ratio (OR) = 0.25, 95% confidence interval (CI):0.15, 0.41 in males, and OR = 0.58, 95% CI: 0.42,0.80 in females, central obesity defined by WC, OR = 0.52, 95% CI:0.39,0.69 in males and OR = 0.63, 95% CI:0.51,0.77 in females). Similarly, restrictive cubic splines showed the nonlinear relationship between high levels of cortisol and different obesity indices. Furthermore, ROC curve analysis indicated that cortisol could improve the discrimination of model with common biomarkers.

CONCLUSION

Morning serum cortisol were negatively related to obesity defined by different indices in Chinese rural populations. In addition, cortisol could be as a biomarker for prediction of obesity in males.

Environmental health conditions in the transitional stage of forcible displacement: A systematic scoping review

In 2019, 30,000 people were forced to leave their homes due to conflict, persecution, and natural disaster each day. Eighty-five percent of refugees live in developing countries, and they often face underfunded and inadequate environmental health services. Many displaced persons live in camps and other temporary settlements long after the displacement event occurs. However, there is little evidence on environmental health conditions in the transitional phase-defined by the United Nations High Commissioner for Refugees as six months to two years after displacement. To address this gap in research, we conducted a systematic scoping review of environmental health conditions, exposures, and outcomes in transitional displacement settings, as well as reported obstacles and recommendations for improvement. Eighty-eight publications met the inclusion criteria. Water supply was the most frequently discussed environmental health topic. Overcrowding was the most common risk factor reported, Vibrio cholerae was the most common pathogen reported, and diarrhea was the most commonly reported health outcome. Obstacles and recommendations were categorized as institutional, political or implementation-based. Identified knowledge gaps included minimal information on setting logistics and on topics such as menstrual hygiene, oral hygiene and fomite contamination. In order to improve environmental health conditions in transitional displacement settings, all levels of government and non-governmental organizations should increase collaboration to improve resource provision. This study is the first to report on environmental health conditions in this important time of transition between the emergency and protracted stages of displacement.

Environmental health conditions in protracted displacement: A systematic scoping review

Adequate environmental health services are critical for human rights, health, and development, especially in the context of forced displacement. There are more than 70 million forcibly displaced persons worldwide, most in protracted situations, having been displaced for more than two years. Some live in camps or informal settlements, but most live in urban areas. Environmental health services are important in the transition from emergency response to sustainable development in these settings, but evidence on environmental health in displaced populations is disparate and of variable quality. We conducted a systematic scoping review of environmental conditions, exposures, and outcomes in protracted displacement settings; obstacles to improvement in environmental health services; and recommendations made for improvement. We included 213 publications from peer-reviewed and grey literature databases. Data were extracted on environmental health topics including water, sanitation, hygiene, overcrowding, waste management, energy supply, vector control, menstrual hygiene, air quality, and food safety. Most studies present data from low- and lower-middle income countries. Northern Africa and Western Asia and Sub-Saharan Africa are the most-represented regions. There is substantial evidence on water, sanitation, and crowding, but few studies report findings on other environmental health topics. Water-related disease, parasites, and respiratory infections are frequently cited and studies report that services often fail to meet international standards for humanitarian response. The most frequent obstacles and recommendations are institutional, political, or implementation-related, but few studies provide concrete recommendations for improvement. Our review compiles and characterizes the research on environmental health in protracted displacement. We recommend including displaced populations in international environmental health policy and monitoring initiatives, and bridging from humanitarian response to sustainable development by preparing for long-term displacement from the early stages of a crisis.

Environmental health in forced displacement: A systematic scoping review of the emergency phase

There are 70.8 million forcibly displaced people worldwide, including internally displaced persons, refugees, and asylum seekers. Since mortality rates are highest in the first six months of displacement, the provision of adequate services and infrastructure by relief organizations is critical in this "emergency phase." Environmental health provisions such as adequate water supply, excreta management, solid waste management, and vector control measures are among those essential services. We conducted a systematic scoping review of environmental health in the emergency phase of displacement (the six months following first displacement). A total of 122 publications, comprising 104 peer-reviewed and 18 grey literature publications, met the inclusion criteria. We extracted data relating to environmental health conditions and services, associated outcomes, and information concerning obstacles and recommendations for improving these conditions and services. Despite the fact that most displaced people live outside of camps, publications largely report findings for camps (n = 73, 60%). Water supply (n = 57, 47%) and excreta management (n = 47, 39%) dominate the literature. Energy access (n = 7, 6%), exposure to harsh weather from inadequate shelter (n = 5, 4%), food hygiene and safety (n = 4, 3%), indoor air quality (n = 3, 3%), menstrual hygiene management (n = 2, 2%), dental hygiene (n = 2, 2%), and ambient air quality (n = 1, 1%) are relatively understudied. The most common health outcome attributed to inadequate environmental conditions in the included publications is diarrhea (n = 43, 35%). We found that organizations and governments often embrace their own standards, however we call for policymakers to adopt standards no less rigorous than Sphere for the emergency phase of displacement. Although other reviews examine water, sanitation, and hygiene interventions in emergencies, this is the first systematic review of environmental health more broadly in the first six months of displacement.

Interfacial Stress in the Development of Biologics: Fundamental Understanding, Current Practice, and Future Perspective

Biologic products encounter various types of interfacial stress during development, manufacturing, and clinical administration. When proteins come in contact with vapor-liquid, solid-liquid, and liquid-liquid surfaces, these interfaces can significantly impact the protein drug product quality attributes, including formation of visible particles, subvisible particles, or soluble aggregates, or changes in target protein concentration due to adsorption of the molecule to various interfaces. Protein aggregation at interfaces is often accompanied by changes in conformation, as proteins modify their higher order structure in response to interfacial stresses such as hydrophobicity, charge, and mechanical stress. Formation of aggregates may elicit immunogenicity concerns; therefore, it is important to minimize opportunities for aggregation by performing a systematic evaluation of interfacial stress throughout the product development cycle and to develop appropriate mitigation strategies. The purpose of this white paper is to provide an understanding of protein interfacial stability, explore methods to understand interfacial behavior of proteins, then describe current industry approaches to address interfacial stability concerns. Specifically, we will discuss interfacial stresses to which proteins are exposed from drug substance manufacture through clinical administration, as well as the analytical techniques used to evaluate the resulting impact on the stability of the protein. A high-level mechanistic understanding of the relationship between interfacial stress and aggregation will be introduced, as well as some novel techniques for measuring and better understanding the interfacial behavior of proteins. Finally, some best practices in the evaluation and minimization of interfacial stress will be recommended.

Long-Range Self-Assembly via the Mutual Lorentz Force of Plasmon Radiation

Long-range interactions often proceed as a sequence of hopping through intermediate, statistically favored events. Here, we demonstrate predictable mechanical dynamics of particles that arise from the Lorentz force between plasmons. Even if the radiation is weak, the nonconservative Lorentz force produces stable locations perpendicular to the plasmon oscillation; over time, distinct patterns emerge. Experimentally, linearly polarized light illumination leads to the formation of 80 nm diameter Au nanoparticle chains, perpendicularly aligned, with lengths that are orders of magnitude greater than their plasmon near-field interaction. There is a critical intensity threshold and optimal concentration for observing self-assembly.

Development and Evaluation of a Pliable Biological Valved Conduit. Part II: Functional and Hemodynamic Evaluation

Many congenital cardiac malformations may require a valved conduit for the reconstruction of the right ventricular outflow tract. In spite of many endeavors made in the last 25 years, the clinical results of right ventricular outflow tract reconstruction with currently available valved conduits are still not satisfactory. Specific problems encountered clinically include suboptimal hemodynamic performance, conduit kinking or compression, and fibrous peeling from the luminal surface. To address these deficiencies, we undertook the development of a biological valved conduit: a bovine external jugular vein graft with a retained native valve cross-linked with a diglycidyl ether (DE). This study, using a canine model, was to evaluate the functional and hemodynamic performance of this newly developed valved conduit. Three 14 mm conduits, implanted as bypass grafts, right ventricle to pulmonary artery, were evaluated. The evaluation was conducted with a noninvasive color Doppler flow mapping system at pre-implantation, immediately post implantation, one- and three-months post implantation, and prior to retrieval (five-months post implantation). The two-dimensional tomographic inspection of the leaflet motion at various periods post implantation showed that the valvular leaflets in the DE treated conduit was quite pliable. No cardiac failure or valvular dysfunction was observed in any of the studied cases. The color Doppler flow mapping study demonstrated that the valve in the DE treated conduit was competent, with no conduit kinking or compression observed in any of the three cases. The spectral Doppler velocity study evidenced that the transvalvular pressure gradients of the DE treated conduit were minimal as compared to those of the currently available conduits. In conclusion, from the functional and hemodynamic performance points of view, this newly developed valved conduit is superior to those currently available.

A Preliminary Study of the Fixation Mechanism of Collagen Reaction with a Polyepoxy Fixative

A new biomaterial has been developed by fixing native collagens with a polyepoxy compound (PC) fixative. Prior studies have shown that this biomaterial has comparable properties as compared to collagen fixed with glutaraldehyde (GA) and thus has a great promise for use as an implantable bioprosthesis. The purpose of this study was to understand the mechanism of the amino acids-PC reactions in the fixation process. Bovine arteries were fixed with PC under various pH, concentration and temperature conditions as a function of fixation time. Individual amino acid components in the fresh and the fixed arteries were assayed using a Beckman amino acid analyzer to determine the degree of tanning. The denaturation temperature (Td) was also measured on each sample. Since the denaturation temperature is a direct indication of cross-linking of individual amino acids with the fixative, the difference in the degree of tanning for the same increase in Td may be indicative of the quantity of the masked, non-cross-linked amino acids. The fixation reaction data indicated that not all amino acids were cross-linked upon contacting the PC fixative. Masking appeared to be more substantial with a fixation at higher pH values.

Development and Evaluation of a Pliable Biological Valved Conduit. Part I: Preparation, Biochemical Properties, and Histological Findings

Different types of external valved conduits have been used for the repair of complex congenital cardiac anomalies that may have otherwise been inoperable. However, an ideal conduit has yet to be found due to complications such as stenosis, thrombosis, calcification of the valve and graft wall, and “peeling” of the neointima. To address those problems, a new extracardiac valved conduit made of bovine jugular vein was developed and evaluated in a preliminary animal study. Harvested bovine vein containing a naturally existing valve was initially incorporated with protamine on the inner surface and then was cross-linked in diglycidyl ether (DE). Fixation with DE allowed the vein and its leaflets to retain a tissue-like elasticity. To provide antithrombogenicity to the graft, heparin was introduced into the lumen to bind ionically to the pre-entrapped protamine. The biological valved conduit of approximately 14 mm diameter was implanted from the right ventricle to pulmonary artery as bypass graft in three dogs. After implantation, the native main pulmonary artery was ligated between the anastomotic sites of the bypass conduit. No anticoagulant or antiplatelet drugs were administered after surgery. One DE-fixed valved conduit was retrieved at 3 months, and the others were removed at 5 months. Only small thrombus areas were found on the white luminal surfaces. The valves and the conduits maintained softness and pliability, similar to before implantation. Additionally, the collagen content, shrink temperature, and tanning index of this newly developed biological valved conduit before and after fixation were measured in the study. These preliminary results suggest that the new valved conduit fixed with DE and heparinized on the lumen may help mitigate the problems observed in the currently available conduits.

Evaluation of Collagen Modification and Surface Properties of a Bovine Artery via Polyepoxy Compound Fixation

Collagen of bovine internal thoracic artery (BITA) was treated with glutaraldehyde (GA) or polyepoxy compounds (PC). This study was to evaluate the surface properties as a result of tissue tanning reaction with PC. The fixation resulted in a significant reduction of available lysine, histidine, and other amino acid residues in PC fixed grafts as compared to fresh pre-fixed arteries. Among them, the lysine (Lys) content was reduced by about 80%, indicating that PC reactions mainly involve with Lys residues. Both PC and GA treatment led to crosslinking as evidenced by the increase in the denaturation temperature. The critical surface tension and the Fourier Transform Infrared Spectrum (FTIR) on a preimplant and its 96 days explant were evaluated and found to be similar. The FTIR analysis of a pre-implant and the 96 day explant indicated that there was no lipid deposition.

Heparinization of Biological Vascular Graft Reduces Fibrin Deposition

An alternative graft is needed for coronary bypass operations in patients lacking suitable autologous vessels. We therefore studied Denaflex™, a biologic graft, in a dog ex-vivo shunt model to determine whether heparin treatment makes this graft less thrombogenic. Comparison was also made to Bioflow™, a nonheparinized biologic graft. Fibrinogen deposition during high flow (593 ± 202 ml/min) decreased from 672 ± 467 ngl mm2 in nonheparinized Denaflex grafts to 448 ± 298 ng/mm2 (p<0.05) in heparinized Denaflex grafts. At low flow (117 ± 13 ml/min), heparinization of Denaflex grafts similarly decreased fibrinogen deposition from 1102 ± 601 ng/mm2 to 703 ± 405 ng/mm2 (p<0.05). At both flow rates fibrinogen deposition in Bioflow grafts was less than in nonheparinized Denaflex, but was similar to heparinized Denaflex grafts. Platelet deposition was not influenced by heparinization of Denaflex grafts and was similar among Denaflex and Bioflow preparations. Whether Denaflex performs acceptably in vivo as a xenograft requires extensive study.

A Compliant Biological Vascular Prosthesis

One requirement of the mechanical parameters for an acceptable vascular prosthesis is compliance. The compliance of a vascular prosthesis is defined as the fractional change in luminal volume per unit change in applied pressure. A compliant prosthesis has been correlated to prosthesis patency and long-term efficacy in an animal study. However, there have been very few reports on how to manufacture a compliant prosthesis. It is the objective of this study to research the processing methods to manufacture a reasonably compliant vascular prosthesis. A new fixative, polyepoxy compound, was used to fix an artery. The arteries were fixed under different degrees of longitudinal retraction. By locking in the collagen micro-structure at an overly relaxed state and then crosslinking said collagen, the resulting biological prosthesis exhibited extreme compliance and pliability. A prosthesis matching its arterial origin in tensile modulus was achieved by crosslinking an artery at its 45% retraction longitudinally. This flexible prosthesis showed a volumetric compliance index of 18.4 ± 0.9 %Δ/100 mmHg and a longitudinal tensile modulus of 942 grams/cm2. Our current study indicated that a prosthesis fixed with polyepoxy compounds has shown more pliability than that with glutaraldehyde. Further animal study to correlate prostheses patency to different degrees of compliance is needed to confirm this proposed manufacturing approach.

Relationship between spicy flavor, spicy food intake frequency, and general obesity in a rural adult Chinese population: The RuralDiab study

BACKGROUND AND AIMS

The purpose of this study was to explore the association between spicy flavor, spicy food frequency, and general obesity in Chinese rural adults.

METHODS AND RESULTS

A total of 15,683 subjects (5907 males, 9776 females) aged 35-74 years from the RuralDiab Study were recruited for this cross-sectional study. Analysis of covariance was used to determine the differences of participant characteristics across body mass index (BMI) categories. Logistic regression yielded adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for obesity associated with the level of spicy flavor and frequency of spicy food intake. A meta-analysis was conducted to validate the result of the cross-sectional study. The crude and standardized prevalence of obesity were 16.78% and 17.57%, respectively. Compared with No spicy flavor, the adjusted ORs (95% CIs) of Mild, Middle, and Heavy spicy flavor for obesity were 1.232 (1.117-1.359), 1.463 (1.290-1.659), and 1.591 (1.293-1.958), respectively (P_trend < 0.001). Similarly, compared with no spicy food consumption, the adjusted ORs (95% CIs) of 1 or 2 days/week, 3-5 days/week, and 6 or 7 days/week were 1.097 (0.735-1.639), 1.294 (0.932-1.796), and 1.250 (1.025-1.525), respectively (P_trend = 0.026). The point estimate and 95% CI of mean BMI difference between the spicy food consuming group and spicy food non-consuming group was 0.37 (95% CI: 0.30-0.44) in the meta-analysis.

CONCLUSION

The data indicated that spicy flavor and spicy food frequency were positively associated with general obesity in Chinese rural populations.

Health Care Economics: A Study Guide for Neuroradiology Fellows, Part 2

In this second article, we continue the review of current health care economics as it relates to radiologists, specifically framed by topics defined by the Accreditation Council for Graduate Medical Education in the evaluation of neuroradiology fellows. The discussion in this article is focused on topics pertaining to levels 4 and 5, which are the more advanced levels of competency defined by the Accreditation Council for Graduate Medical Education Neuroradiology Milestones on Health Care Economics and System Based Practice.

Health Care Economics: A Study Guide for Neuroradiology Fellows, Part 1

Few resources are available in the medical literature for a comprehensive review of current health care economics as it relates to radiologists, specifically framed by topics defined by the Accreditation Council for Graduate Medical Education in the evaluation of neuroradiology fellows. Therefore, we present a comprehensive review article as a study guide for fellows to learn from and gain competence in the Accreditation Council for Graduate Medical Education neuroradiology milestones on health care economics.

Prostaglandin E2 regulates renal function in C57/BL6 mouse with 5/6 nephrectomy

AIMS

To investigate the roles of cyclooxygenases (COX) and their metabolites in C57/BL6 mice with 5/6 nephrectomy, an animal model of chronic renal failure.

MAIN METHODS

C57/BL6 mice were grouped into sham-operated (2K), one kidney removal (1K) and 5/6 nephrectomy groups (5/6Nx). Renal resistive index was measured by ultrasonography. Blood, aortae, renal arteries and renal cortex were collected for measurement of kidney function, assessment of vascular responsiveness, Western blotting, immuohistochemistry and enzyme-linked immunosorbent assays.

KEY FINDINGS

After four weeks, acetylcholine-induced relaxations were blunted in renal arteries of 1K and 5/6Nx mice; indomethacin, a non-selective COX inhibitor, improved the response in 5/6Nx, but not in 1K renal arteries. In 5/6Nx renal arteries, but not in 1K preparations, the protein presence of endothelial nitric oxide synthase (eNOS) was decreased, while that of COX-2 and its products [prostacyclin and thromboxane A₂] were increased. The renal resistive index was lower in 5/6Nx mice, suggesting a lower resistance in the renal microvasculature. In the renal cortex of 5/6Nx mice, eNOS protein presence was increased; while the presence of COX-2 was not detectable. The prostaglandin E₂ level was lower in the 5/6Nx cortex than in the other two groups.

SIGNIFICANCE

The early stage of renal mass removal is associated with increased renal arterial constriction and reduced microvascular resistance. The former is due to downregulation of eNOS and upregulation of COX-2, leading to an increased production of prostacyclin and thromboxane A₂. A reduced production of PGE₂ in the renal cortex is important for maintaining normal renal function.

Current Procedural Terminology: History, Structure, and Relationship to Valuation for the Neuroradiologist

The year 1965 was critical for US health care policy. In that year, Medicare was created as part of the Social Security Act under President Lyndon B. Johnson after several earlier attempts by Presidents Franklin Roosevelt and Harry Truman. In 1966, the American Medical Association first published a set of standard terms and descriptors to document medical procedures, known as Current Procedural Terminology, or CPT. Fifty years later, though providers have certainly heard the term "CPT code," most would benefit from an enhanced understanding of the historical basis, current structure, and relationship to valuation of Current Procedural Terminology. This article will highlight this evolution, particularly as it relates to neuroradiology.

Quantification of transient increase of the blood-brain barrier permeability to macromolecules by optimized focused ultrasound combined with microbubbles

Radioimmunotherapy using a radiolabeled monoclonal antibody that targets tumor cells has been shown to be efficient for the treatment of many malignant cancers, with reduced side effects. However, the blood-brain barrier (BBB) inhibits the transport of intravenous antibodies to tumors in the brain. Recent studies have demonstrated that focused ultrasound (FUS) combined with microbubbles (MBs) is a promising method to transiently disrupt the BBB for the drug delivery to the central nervous system. To find the optimal FUS and MBs that can induce reversible increase in the BBB permeability, we employed minimally invasive multiphoton microscopy to quantify the BBB permeability to dextran-155 kDa with similar molecular weight to an antibody by applying different doses of FUS in the presence of MBs with an optimal size and concentration. The cerebral microcirculation was observed through a section of frontoparietal bone thinned with a micro-grinder. About 5 minutes after applying the FUS on the thinned skull in the presence of MBs for 1 minute, TRITC (tetramethylrhodamine isothiocyanate)-dextran-155 kDa in 1% bovine serum albumin in mammalian Ringer's solution was injected into the cerebral circulation via the ipsilateral carotid artery by a syringe pump. Simultaneously, the temporal images were collected from the brain parenchyma ~100-200 μm below the pia mater. Permeability was determined from the rate of tissue solute accumulation around individual microvessels. After several trials, we found the optimal dose of FUS. At the optimal dose, permeability increased by ~14-fold after 5 minutes post-FUS, and permeability returned to the control level after 25 minutes. FUS without MBs or MBs injected without FUS did not change the permeability. Our method provides an accurate in vivo assessment for the transient BBB permeability change under the treatment of FUS. The optimal FUS dose found for the reversible BBB permeability increase without BBB disruption is reliable and can be applied to future clinical trials.

Diagnostic carotid and cerebral angiography: a historical summary of the evolving changes in coding and reimbursement in a complex procedure family

Carotid and cerebral angiography have been a mainstay of neurointerventional and neuroradiologic practice for years. Centers for Medicare and Medicaid Services (CMS) and Relative Value Scale Update Committee (RUC) initiatives have compelled the professional societies to bundle component codes under threat of unilateral CMS revision and revaluation. Code bundling usually results in a decrease in the professional Relative Value Unit (RVU) valuation, and thus the MD reimbursement. The year 2013 saw a dramatic revision to the Current Procedural Terminology (CPT) code set that defines carotid and cerebral procedures. This paper reviews the process that led to that code set being revised and estimates the impact on professional reimbursement. We show the current and previous carotid angiography CPT codes and use clinical examples to assess professional RVU valuation before and after code revision.

Current procedural terminology; a primer

In 1966, The American Medical Association (AMA) working with multiple major medical specialty societies developed an iterative coding system for describing medical procedures and services using uniform language, the Current Procedural Terminology (CPT) system. The current code set, CPT IV, forms the basis of reporting most of the services performed by healthcare providers, physicians and non-physicians as well as facilities allowing effective, reliable communication among physician and other providers, third parties and patients. This coding system and its maintenance has evolved significantly since its inception, and now goes well beyond its readily perceived role in reimbursement. Additional roles include administrative management, tracking new and investigational procedures, and evolving aspects of 'pay for performance'. The system also allows for local, regional and national utilization comparisons for medical education and research. Neurointerventional specialists use CPT category I codes regularly--for example, 36,215 for first-order cerebrovascular angiography, 36,216 for second-order vessels, and 37,184 for acute stroke treatment by mechanical means. Additionally, physicians add relevant modifiers to the CPT codes, such as '-26' to indicate 'professional charge only,' or '-59' to indicate a distinct procedural service performed on the same day.

Micro-computerized tomography assessment of fluorescence aided caries excavation (FACE) technology: comparison with three other caries removal techniques

BACKGROUND

The aim of this study was to determine the caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of four dentine caries removal methods.

METHODS

After carious molars were scanned using micro-computerized tomography (micro-CT), dentine caries were removed by fluorescence aided caries excavation (FACE) technology, laser induced fluorescence (LIF), chemomechanical excavation (CME), and conventional excavation (CE). Micro-CT was then repeated. CRE was determined based on the volume of residual caries/initial caries (RC/IC) and the mean mineral density (MD) at the cavity floor. MIP was determined by measuring the volume of the prepared cavity/initial cavity (PC/IC).

RESULTS

Among the four groups, the LIF group had the smallest RC/IC (0.08), the highest mean MD at the cavity floor (1.32 g/cm(3) ) and the highest MIP (4.47). The CME group had the highest RC/IC (0.24), the lowest mean MD (1.01 g/cm(3) ) and the lowest MIP (2.23). The CE group exhibited a more acceptable CRE (RC/IC = 0.13, mean MD = 1.21 g/cm(3) ) but had a higher MIP (3.95). Both the CRE and MIP parameters of FACE technology were the second most acceptable (RC/IC = 0.12, mean MD = 1.13 g/cm(3) , MIP = 3.20) and did not differ significantly from the most acceptable.

CONCLUSIONS

FACE is an effective caries removal technology for removing infected dentine without significantly increasing cavity size.

Tether-supported biomembranes with α-helical peptide-based anchoring constructs

The strict requirement of constructing a native lipid environment to preserve the structure and functionality of membrane proteins is the starting constraint when building biomaterials and sensor systems from these biomolecules. To enhance the viability of supported biomembranes systems and build new ligand display interfaces, we apply rationally designed peptides partitioned into the lipid bilayer interface. Peptides designed to form membrane-spanning α-helical anchoring domains are synthesized using solid-phase peptide synthesis. K(3)A(4)L(2)A(7)L(2)A(3)K(2)-FITC is synthesized on the 100 mg scale for use as a biomembrane anchoring molecule, where orthogonal side-chain modifications allow us to introduce probes enabling peptide localization within supported bilayers. The peptides are found to form α-helical domains within liposomes as assessed with circular dichroism spectroscopy. These peptides are designed to be incorporated into lipid bilayers supported by microspheres and serve as biomembrane anchoring moieties to amino-terminated surfaces. Here, the silica bead surface (4.7 μm diameter) is activated with homobifunctional NHS-PEG(3000)-NHS as "polymer cushion" spacers. This tethering to a subset of the K(3)A(4)L(2)A(7)L(2)A(3)K(2)-FITC molecules present in the bilayer is achieved by the fusion of liposomes followed by coupling of the peptide amino groups to the NHS presented from the silica microsphere surfaces. The biomembrane distributions of tethered and untethered K(3)A(4)L(2)A(7)L(2)A(3)K(2)-FITC are probed with confocal microscopy and are found to give 3D reconstructions consistent with largely homogeneous supported biomembranes. The fluidity of the untethered fraction of peptides within supported membranes is quantified using the fluorescence recovery after photobleaching (FRAP) technique. The presence of the PEG(3000) polymer cushion facilitated a 28.9% increase in peptide diffusivity over untethered bilayers at the lowest peptide to lipid ratio we examined. We show that rationally designed peptide-based anchors can be used to tether lipid bilayers, creating a polymer-cushioned lipid microenvironment on surfaces with high lateral mobility and facilitating the development of a new platform for ligand displays.

Engineering of an environmentally responsive beta roll peptide for use as a calcium-dependent cross-linking domain for peptide hydrogel formation

We have created a set of rationally designed peptides that form calcium-dependent hydrogels based on the beta roll peptide domain. In the absence of calcium, the beta roll domain is intrinsically disordered. Upon the addition of calcium, the peptide forms a beta helix secondary structure. We have designed two variations of our beta roll domain. First, we have mutated one face of the beta roll domain to contain leucine residues so that the calcium-dependent structural formation leads to dimerization through hydrophobic interactions. Second, an α-helical leucine zipper domain is appended to the engineered beta roll domain as an additional means of forming intermolecular cross-links. This full peptide construct forms a hydrogel only in calcium-rich environments. The resulting structural and mechanical properties of the supramolecular assemblies are compared with the wild-type domain using several biophysical techniques including circular dichroism, FRET, bis-ANS binding and microrheology. The calcium responsiveness and rheological properties of the leucine beta roll containing construct confirm the potential of this allosterically regulated scaffold to serve as a cross-linking domain for stimulus-responsive biomaterials development.

Self-assembly of rationally designed peptides under two-dimensional confinement

The rational design of interfacially confined biomolecules offers a unique opportunity to explore the cooperative relationship among self-assembly, nucleation, and growth processes. This article highlights the role of electrostatics in the self-assembly of β-sheet-forming peptides at the air-water interface. We characterize the phase behavior of a periodically sequenced sheet-forming peptide by using Langmuir techniques, Brewster angle microscopy, attenuated total reflection Fourier transform infrared spectroscopy, and circular dichroism spectroscopy. We find that peptides with an alternating binary sequence transition at high pressures from discrete circular domains to fibrous domains. The qualitative behavior is independent of surface pressure but dependent on molecular areas. In addition, thermodynamic models are employed to specifically quantify differences in electrostatics by obtaining parameters for the critical aggregation area, the limiting molecular area, and the dimensionless ratio of line tension/dipole density. Using these parameters, we are able to relate localized charge distribution to phase transitions, which will allow us to apply these molecules to examine how the dynamics of self-assembly can be directly coupled to the formation of composite nanostructures in biology.

Identification of nitrogen-fixing Paenibacillus from different plant rhizospheres and a novel nifH gene detected in the P. stellifer

A total of 534 isolates were selectively obtained from different plant rhizospheres based on their growth on nitrogen-free medium and their resistance to 80 degrees C for 15 min. Of the 534 isolates, 23 isolates had nifH gene and exhibited nitrogenase activities. Based on 16S rDNA sequence, G + C content assay and DNA-DNA hybridization, by the 23 isolates, which were divided into four monophyletic clusters, all belonged to the Paenibacillus genus. NifH gene deduced amino acid alignment analysis revealed that cluster I, including 15 isolates, showed the highest NifH identity with Paenibacillus genus; while cluster II identified as P stellifer by DNA-DNA hybridization was consistent with four uncultured bacterial clones. This study suggested that the nitrogen-fixing Paenibacillus were distributed in various ecosystems and prevalent in different plant rhizospheres. It was the first demonstration that nitrogen fixation existed in P. jamilae and P. stellifer. In eight isolates identified as P. stellfer species, a novel nifH gene was detected in Paenibacillus.

Peptide-mediated targeting of liposomes to tumor cells

One of the biggest obstacles for efficient drug delivery is specific cellular targeting. Liposomes have long been used for drug delivery, but do not possess targeting capabilities. This limitation may be circumvented by surface coating of colloidal delivery systems with peptides, proteins, carbohydrates, vitamins, or antibodies that target cell surface receptors or other biomolecules. Each of these coatings has significant drawbacks. One idealized system for drug delivery combines stabilized "protein module" ligands with a colloidal delivery vehicle. Prior studies have shown that peptide-amphiphiles, whereby both a peptide "head group" and a lipid-like "tail" are present in the same molecule, can be used to engineer collagen-like triple-helical or alpha-helical miniproteins. The tails serve to stabilize the head group structural elements. These peptide-amphiphiles can be designed to bind to specific cell surface receptors with high affinity. Structural stabilization of the integrated targeting ligand in the peptide-amphiphile system equates to prolonged in vivo stability through resistance to proteolytic degradation. Liposomes have been prepared incorporating a melanoma targeting peptide-amphiphile ligand, and shown to be stable with retention of peptide-amphiphile triple-helical structure. Encapsulated fluorescent dyes are selectively delivered to cells. In this chapter we describe the methods and techniques employed in the preparation and characterization of peptide-amphiphiles and peptide-amphiphile-targeted large and small unilamellar vesicles (LUVs and SUVs). Fluorescence microscopy is subsequently utilized to examine the targeting capabilities of peptide-amphiphile LUVs, which should allow for improved drug selectivity towards melanoma vs normal cells based on differences in the relative abundance of the targeted cell surface receptors.

Multimodal near infrared spectral imaging as an exploratory tool for dysplastic esophageal lesion identification

We explore nine different combinations of fluorescence, light scattering, and polarization spectral imaging approaches in the near-infrare spectral region toward the diagnosis of pathologic and normal esophageal lesions. The combinations of all the imaging techniques were evaluated for maximal sensitivity and specificity. The results suggest that this multimodal approach is capable of highly accurate detection of the presence of pathologic tissue.

Cell adhesion on a polymerized peptide–amphiphile monolayer

We report the synthesis and characterization of a stable polymerized monolayer of peptide-amphihiles on a planar solid support that promotes mouse fibroblast cell adhesion and spreading. Peptide-amphiphiles consisting of a polymerizable fatty acid attached to a short RGD containing peptide sequence are self-assembled and polymerized at the water-air interface by means of the Langmuir- Blodgett technique. The surface concentration of the peptide-amphiphile is varied by co-spreading the peptide-amphiphile with an analogous non-modified polymerizable amphiphile at the water/air interface, prior to UV light-induced polymerization. The polymerized monolayer is transferred onto a hydrophobized smooth mica surface and the resulting surfaces have been investigated with respect to directing the cell adhesion and spreading of mouse fibroblast cells in a serum-free medium. Fibroblast cells adhere and spread on surfaces exposing the bioactive ligand but do not spread on reference surfaces without peptide. We find a maximum number of adherent cells at rather high peptide surface concentrations of about 10 mol% in the mixed monolayer, equivalent to more than 50 pmol/cm2 peptide on the surface of the film. We attribute this finding to a limited accessibility of the ligands by the integrins. Because of the stability of the polymerized peptide-amphiphile monolayer, these surfaces can be re-seeded multiple times with cells, i.e. adherent cells can be removed from the surface, the surface can be sterilized and cells can be re-attached.

Self-assembly of model DNA-binding peptide amphiphiles

Peptide amphiphiles combine the specific functionality of proteins with the engineering convenience of synthetic amphiphiles. These molecules covalently link a peptide headgroup, typically from an active fragment of a larger protein, to a hydrophobic alkyl tail. Our research is aimed at forming and characterizing covalently stabilized, self-assembled, peptide-amphiphile aggregates that can be used as a platform for the examination and modular design and construction of systems with engineering biological activity. We have studied the self-assembly properties of a model DNA-binding amphiphile, having a GCN4 peptide as the headgroup and containing a polymerizable methacrylic group in the tail region, using a combination of small-angle X-ray scattering, small-angle neutron scattering, and cryo- transmission electron microscopy. Our results reveal a variety of morphologies in this system. The peptide amphiphiles assembled in aqueous solution to helical ribbons and tubules. These structures transformed into lamella upon DNA binding. In contrast with common surfactants, the specific interaction between the headgroups seems to play an important role in determining the microstructure. The geometry of the self-assembled aggregate can be controlled by means of adding a cosurfactant. For example, the addition of SDS induced the formation of spherical micelles.

Polymerized vesicles containing molecular recognition sites

Vesicles are prepared from diacetylenic peptide amphiphiles that expose a molecular recognition site at the surface. The amphiphiles can be polymerized using UV light, and the resulting polymeric vesicles exhibit interesting chromatic responses that can be used for label-free detection of the interaction with a distinct protein in solution.

Human PDE5A gene encodes three PDE5 isoforms from two alternate promoters

Sildenafil improves erectile function by inhibiting the cGMP-catalytic activity of phosphodiesterase type V (PDE5). We used rapid amplification of cDNA Ends-polymerase chain reaction (RACE-PCR) to isolate three PDE5 isoforms from human corpus cavernosum. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis on eight human cavernous tissue samples showed that all samples expressed the PDE5A1 at a lower level than the PDE5A2 isoform. Five samples expressed the PDE5A3 isoform at various levels while the other three did not. Analysis on non-penile tissues showed that all tissues expressed the A1 and A2 isoforms while only those that have substantial amounts of smooth muscle expressed the A3 isoform. Cloning and sequencing of the PDE5A gene showed that the isoform-specific 5'-ends of the PDE5 mRNAs are encoded from three alternative first exons arranged in the order of A1-A3-A2. Promoter activities were detected upstream from the A1-specific exon and in the intron preceding the A2-specific exon. The upstream PDE5A promoter is expected to direct the expression of all three PDE5 isoforms while the intronic PDE5A2 promoter only the A2 isoform. Both promoters were upregulated by increasing concentrations of either cAMP or cGMP. Several transcription factor AP2 and Sp1-binding sequences identified in the promoters are likely to be the mediators of cAMP/cGMP-responsiveness.

Age-related decrease of protein kinase G activation in vascular smooth muscle cells

Protein kinase G-I (PKG-I) activation is essential for vascular relaxation; however, its quantitative analysis in intact cells has been difficult. To overcome this difficulty, a monoclonal antibody, VASP-16C2, was recently developed that detects phosphorylated serine residue 239 of vasodilator-stimulated phosphoprotein (VASP), a substrate of PKG-I. In this study, we used this antibody to examine (i) possible functional differences between the alpha and beta isoforms of PKG-I, (ii) ability of cAMP to activate PKG-I, as compared to cGMP, the principal PKG-I-activating cyclic nucleotide, and (iii) time course and levels of PKG-I activation in vascular smooth muscle cells (VSMC) of young and old rats. We created COS-7 cell clones that overexpressed PKG-Ialpha or PKG-Ibeta, treated them with cAMP or cGMP, and analyzed their cell lysates for reactivity with VASP-16C2. The results showed that PKG-Ialpha phosphorylated VASP at a higher level than PKG-Ibeta, and cAMP was slightly weaker than cGMP in PKG-I activation. VSMC of young rats responded to cAMP or cGMP stimulation in a dose-dependent manner with increasing levels of PKG-I activation. The response was detected within 10 min and continued for at least 24 h. In contrast, VSMC of old rats showed no PKG-I activation during the first hour of cAMP or cGMP stimulation and, at 24 h these cells showed only low-level PKG-I activation. We propose that the reduced PKG-I activation may explain why vascular relaxation is decreased in older individuals.

Identification and regulation of human PDE5A gene promoter

PDE5A gene encodes type 5 phosphodiesterase (PDE5), the principal cGMP-catalyzing enzyme in the penis and the primary target of sildenafil (Viagra). We have isolated a 3.7-kb DNA fragment that contains the human PDE5A gene promoter. The DNA fragment contains a sequence of 234 nucleotides at its 3' end that corresponds to most of the untranslated region of the PDE5A1 mRNA. The remaining 3.5-kb upstream flanking sequence contains no apparent TATA box but has several sequences that resemble binding sequences for transcription factors such as androgen receptor (AR), AP1, AP2, AP4, Sp1, MyoD, Myc, and CArG. In search of promoter activities, we used a luciferase reporter system to examine 10 DNA fragments that cover various regions of the 3.7-kb fragment. We found that a full basal promoter activity was confined to a 139-bp region that includes 78 bp of the PDE5A1-specific first exon. A lesser basal promoter activity was still detectable in a 94-bp fragment that contains the same 78-bp PDE5A1-specific exon plus 16 bp of upstream sequence. Either the 139-bp or the 94-bp promoter fragment responded minimally to cAMP or cGMP (2 mM) stimulation. Longer fragments that contain either a 308-bp 5' extension (from the 138-bp fragment) or a 156-bp 3' extension (all exon sequence) responded at higher levels to cAMP and cGMP stimulation. The 5' and 3' extensions cooperated with each other to provide the highest level of responses to cAMP and cGMP stimulation. DNase I footprint analysis identified four AP2- and two Sp1-binding sites in the 5' extension and four Sp1-binding sites in the 3' extensions. Cyclic AMP and cGMP had similar stimulatory effects on the PDE5A promoter.