Smart Contact Lens Systems for Ocular Drug Delivery and Therapy

Ocular drug delivery and therapy systems have been extensively investigated with various methods including direct injections, eye drops and contact lenses. Nowadays, smart contact lens systems are attracting a lot of attention for ocular drug delivery and therapy due to their minimally invasive or non-invasive characteristics, highly enhanced drug permeation, high bioavailability, and on-demand drug delivery. Furthermore, smart contact lens systems can be used for direct light delivery into the eyes for biophotonic therapy replacing the use of drugs. Here, we review smart contact lens systems which can be classified into two groups of drug-eluting contact lens and ocular device contact lens. More specifically, this review covers smart contact lens systems with nanocomposite-laden systems, polymeric film-incorporated systems, micro and nanostructure systems, iontophoretic systems, electrochemical systems, and phototherapy systems for ocular drug delivery and therapy. After that, we discuss the future opportunities, challenges and perspectives of smart contact lens systems for ocular drug delivery and therapy.

Bimetallic Nanocatalysts Immobilized in Nanoporous Hydrogels for Long-Term Robust Continuous Glucose Monitoring of Smart Contact Lens

Smart contact lenses for continuous glucose monitoring (CGM) have great potential for huge clinical impact. To date, their development has been limited by challenges in accurate detection of glucose without hysteresis for tear glucose monitoring to track the blood glucose levels. Here, long-term robust CGM in diabetic rabbits is demonstrated by using bimetallic nanocatalysts immobilized in nanoporous hydrogels in smart contact lenses. After redox reaction of glucose oxidase, the nanocatalysts facilitate rapid decomposition of hydrogen peroxide and nanoparticle-mediated charge transfer with drastically improved diffusion via rapid swelling of nanoporous hydrogels. The ocular glucose sensors result in high sensitivity, fast response time, low detection limit, low hysteresis, and rapid sensor warming-up time. In diabetic rabbits, smart contact lens can detect tear glucose levels consistent with blood glucose levels measured by a glucometer and a CGM device, reflecting rapid concentration changes without hysteresis. The CGM in a human demonstrates the feasibility of smart contact lenses for further clinical applications.

Supramolecular host-guest hyaluronic acid hydrogels enhance corneal wound healing through dynamic spatiotemporal effects

Severe corneal wounds can lead to ulceration and scarring if not promptly and adequately treated. Hyaluronic acid (HA) has been investigated for the treatment of corneal wounds due to its remarkable biocompatibility, transparency and mucoadhesive properties. However, linear HA has low retention time on the cornea while many chemical moieties used to crosslink HA can cause toxicity, which limits their clinical ocular applications. Here, we used supramolecular non-covalent host-guest interactions between HA-cyclodextrin and HA-adamantane to form shear-thinning HA hydrogels and evaluated their impact on corneal wound healing. Supramolecular HA hydrogels facilitated adhesion and spreading of encapsulated human corneal epithelial cells ex vivo and improved corneal wound healing in vivo as an in situ-formed, acellular therapeutic membrane. The HA hydrogels were absorbed within the corneal stroma over time, modulated mesenchymal cornea stromal cell secretome production, reduced cellularity and inflammation of the anterior stroma, and significantly mitigated corneal edema compared to treatment with linear HA and untreated control eyes. Taken together, our results demonstrate supramolecular HA hydrogels as a promising and versatile biomaterial platform for corneal wound healing.

Wireless smart contact lens for diabetic diagnosis and therapy

A smart contact lens can be used as an excellent interface between the human body and an electronic device for wearable healthcare applications. Despite wide investigations of smart contact lenses for diagnostic applications, there has been no report on electrically controlled drug delivery in combination with real-time biometric analysis. Here, we developed smart contact lenses for both continuous glucose monitoring and treatment of diabetic retinopathy. The smart contact lens device, built on a biocompatible polymer, contains ultrathin, flexible electrical circuits and a microcontroller chip for real-time electrochemical biosensing, on-demand controlled drug delivery, wireless power management, and data communication. In diabetic rabbit models, we could measure tear glucose levels to be validated by the conventional invasive blood glucose tests and trigger drugs to be released from reservoirs for treating diabetic retinopathy. Together, we successfully demonstrated the feasibility of smart contact lenses for noninvasive and continuous diabetic diagnosis and diabetic retinopathy therapy.

High-throughput single-cell live imaging of photobiomodulation with multispectral near-infrared lasers in cultured T cells

SIGNIFICANCE

Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology.

AIM

Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light.

APPROACH

In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature.

RESULTS

A specific combination of wavelengths at low irradiances (250 to 400  mW  /  cm2 for 1064 nm and 55 to 65  mW  /  cm2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes.

CONCLUSIONS

This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.

Multifunctional materials for implantable and wearable photonic healthcare devices

Numerous light-based diagnostic and therapeutic devices are routinely used in the clinic. These devices have a familiar look as items plugged in the wall or placed at patients' bedsides, but recently, many new ideas have been proposed for the realization of implantable or wearable functional devices. Many advances are being fuelled by the development of multifunctional materials for photonic healthcare devices. However, the finite depth of light penetration in the body is still a serious constraint for their clinical applications. In this Review, we discuss the basic concepts and some examples of state-of-the-art implantable and wearable photonic healthcare devices for diagnostic and therapeutic applications. First, we describe emerging multifunctional materials critical to the advent of next-generation implantable and wearable photonic healthcare devices and discuss the path for their clinical translation. Then, we examine implantable photonic healthcare devices in terms of their properties and diagnostic and therapeutic functions. We next describe exemplary cases of noninvasive, wearable photonic healthcare devices across different anatomical applications. Finally, we discuss the future research directions for the field, in particular regarding mobile healthcare and personalized medicine.

Hyaluronate-Gold Nanoparticle/Glucose Oxidase Complex for Highly Sensitive Wireless Noninvasive Glucose Sensors

Noninvasive real-time biosensors to measure glucose levels in the body fluids have been widely investigated for continuous glucose monitoring of diabetic patients. However, they suffered from low sensitivity and reproducibility due to the instability of nanomaterials used for glucose biosensors. Here, we developed a hyaluronate-gold nanoparticle/glucose oxidase (HA-AuNP/GOx) complex and an ultralow-power application-specific integrated circuit chip for noninvasive and robust wireless patch-type glucose sensors. The HA-AuNP/GOx complex was prepared by the facile conjugation of thiolated HA to AuNPs and the following physical binding of GOx. The wireless glucose sensor exhibited slow water evaporation (0.11 μL/min), fast response (5 s), high sensitivity (12.37 μA·dL/mg·cm²) and selectivity, a low detection limit (0.5 mg/dL), and highly stable enzymatic activity (∼14 days). We successfully demonstrated the strong correlation between glucose concentrations measured by a commercially available blood glucometer and the wireless patch-type glucose sensor. Taken together, we could confirm the feasibility of the wireless patch-type robust glucose sensor for noninvasive and continuous diabetic diagnosis.

Cancer Mechanobiology: Microenvironmental Sensing and Metastasis

The cellular microenvironment plays an important role in regulating cancer progress. Cancer can physically and chemically remodel its surrounding extracellular matrix (ECM). Critical cellular behaviors such as recognition of matrix geometry and rigidity, cell polarization and motility, cytoskeletal reorganization, and proliferation can be changed as a consequence of these ECM alternations. Here, we present an overview of cancer mechanobiology in detail, focusing on cancer microenvironmental sensing of exogenous cues and quantification of cancer-substrate interactions. In addition, mechanics of metastasis classified with tumor progression will be discussed. The mechanism underlying cancer mechanosensation and tumor progression may provide new insights into therapeutic strategies to alleviate cancer malignancy.

Multimodal Cancer Theranosis Using Hyaluronate-Conjugated Molybdenum Disulfide

Among various 2D nanomaterials, molybdenum disulfide (MoS₂ ) exhibits unique visible photoluminescence with high absorption at the near-infrared (NIR) range. Despite these optical properties, the efforts to use MoS₂ nanomaterials for optical imaging and photothermal therapy are hampered by their instability and low intracellular delivery efficiency. Multifunctional MoS₂ conjugated with hyaluronate (HA) for cancer theranosis is reported herein. HA facilitates the delivery of MoS₂ to tumor cells by the HA-receptor mediated endocytosis. In BALB/c nude mice inoculated with a colorectal cancer cell line of HCT116, HA-MoS₂ conjugates appear to be accumulated in the primary tumor at a content more than that in the liver and kidney. The disulfide bonding between MoS₂ and thiolated HA seems to degrade in the cytoplasm, releasing MoS₂ sheets in stacks and enhancing luminescence efficiency. The HA-MoS₂ conjugates are readily detected via photoacoustic imaging as well as upconversion and downconversion fluorescence imaging. With NIR light illumination, HA-MoS₂ conjugates enable highly effective photothermal tumor ablation. All these results confirm the promising potential of HA-MoS₂ conjugates for cancer theranosis.

Predictors of Non-adherence to Immunosuppressive Therapy in Asian Liver Transplant Recipients

BACKGROUND

Adherence to immunosuppressive medications has been shown to affect post-transplant outcomes. We aimed to determine the level of adherence to immunosuppressive therapy in liver transplant (LT) recipients and to elucidate factors associated with it, as well as patient preferences on the dosing schedule.

METHODS

LT recipients were recruited during transplant clinic follow-up. A validated Morisky 8-item questionnaire was completed by patients to assess their adherence to immunosuppressive therapy. Adherence was determined by the sum of the responses to the questionnaire. Low, medium, and high adherence were defined by a Morisky score of >2, 1 to 2, and 0, respectively. Data on the patient's socio-economic and clinical background, dosing schedule of immunosuppressant medications, and patient preferences were included in the questionnaire.

RESULTS

A total of 107 LT recipients were approached and 75 completed the questionnaire. The majority of patients (48/74, 64.9%) preferred a once-daily medication regimen. The proportion of high adherence was 24/75 (32.0%), medium adherence was 51/75 (42.7%), and low adherence was 19/75 (25.3%). Multivariate analysis showed younger age and post-transplant duration >5 years as independent predictors for low adherence. Among low-adherence patients, 16/19 (84.2%) patients were on a twice-daily regimen, and, of these, 14/16 (87.5%) preferred their medications to be reduced to once daily.

CONCLUSIONS

A significant proportion (68%) of LT recipients had low to moderate adherence to medications, with younger age and longer post-transplant duration of >5 years as independent predictors. Early identification of at-risk patients is essential to allow implementation of measures to improve adherence. Simplifying medication regimens to once daily is a potential way to improve adherence.

Light-Guided Nanomotor Systems for Autonomous Photothermal Cancer Therapy

Machines have greatly contributed to the human civilization, enabling tasks beyond our capacities for improved quality of life. Recently, the progress in nanotechnology has triggered to build a miniaturized machine of nanoscale. In this context, synthetic nanomotors have gained considerable interest because of their great promise for diverse applications. Currently, the movement control of these nanomotors has been widely investigated using various stimuli. Here, we demonstrate near-infrared (NIR) light controlled on/off motion of stomatocyte nanomotors powered by the conversion of hydrogen peroxide. The nanomotors encapsulating naphthalocyanine (NC) are aggregated or separated (collective motion) with or without near-IR light illumination, resulting in the well-controlled movement. Remarkably, the nanomotors can move directionally toward hydrogen peroxide released from cancer cells and photothermally ablate the cancer cells. Taken together, our stomatocyte nanomotor systems can be effectively harnessed for autonomous photothermal cancer therapy.

Enhanced oxygen permeability in membrane-bottomed concave microwells for the formation of pancreatic islet spheroids

Oxygen availability is a critical factor in regulating cell viability that ultimately contributes to the normal morphogenesis and functionality of human tissues. Among various cell culture platforms, construction of 3D multicellular spheroids based on microwell arrays has been extensively applied to reconstitute in vitro human tissue models due to its precise control of tissue culture conditions as well as simple fabrication processes. However, an adequate supply of oxygen into the spheroidal cellular aggregation still remains one of the main challenges to producing healthy in vitro spheroidal tissue models. Here, we present a novel design for controlling the oxygen distribution in concave microwell arrays. We show that oxygen permeability into the microwell is tightly regulated by varying the poly-dimethylsiloxane (PDMS) bottom thickness of the concave microwells. Moreover, we validate the enhanced performance of the engineered microwell arrays by culturing non-proliferated primary rat pancreatic islet spheroids on varying bottom thickness from 10 μm to 1050 μm. Morphological and functional analyses performed on the pancreatic islet spheroids grown for 14 days prove the long-term stability, enhanced viability, and increased hormone secretion under the sufficient oxygen delivery conditions. We expect our results could provide knowledge on oxygen distribution in 3-dimensional spheroidal cell structures and critical design concept for tissue engineering applications.

STATEMENT OF SIGNIFICANCE

In this study, we present a noble design to control the oxygen distribution in concave microwell arrays for the formation of highly functional pancreatic islet spheroids by engineering the bottom of the microwells. Our new platform significantly enhanced oxygen permeability that turned out to improve cell viability and spheroidal functionality compared to the conventional thick-bottomed 3-D culture system. Therefore, we believe that this could be a promising medical biotechnology platform to further develop high-throughput tissue screening system as well as in vivo-mimicking customised 3-D tissue culture systems.

Targeted Hyaluronate-Hollow Gold Nanosphere Conjugate for Anti-Obesity Photothermal Lipolysis

Obesity is associated with the risk of developing several severe diseases, such as metabolic disorder, diabetes, and heart diseases. Despite wide investigation and trials, a noninvasive obesity therapy is still an important medical unmet need, targeting the abnormal adipose tissue. Here, we developed hyaluronate-hollow gold nanosphere-adipocyte-targeting peptide (HA-HAuNS-ATP) conjugates for the photothermal ablation of adipose tissues. The HA-HAuNS-ATP conjugate could be noninvasively delivered into the skin and effectively target to adipocytes in the subcutaneous. With near-infrared laser illumination, HA-HAuNS-ATP conjugate enabled highly effective photothermal ablation of adipose tissues in C57BL/6 obesity mice. The photoacoustic imaging confirmed the successful transdermal delivery and the photothermal lipolysis of HA-HAuNS-ATP conjugate. Taken together, the transdermal HA-HAuNS-ATP conjugate might have a great potential for noninvasive photothermal lipolysis.

Liver failure determines the outcome in patients of acute-on-chronic liver failure (ACLF): comparison of APASL ACLF research consortium (AARC) and CLIF-SOFA models

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is a progressive disease associated with rapid clinical worsening and high mortality. Early prediction of mortality and intervention can improve patient outcomes. We aimed to develop a dynamic prognostic model and compare it with the existing models.

METHODS

A total of 1402 ACLF patients, enrolled in the APASL-ACLF Research Consortium (AARC) with 90-day follow-up, were analyzed. An ACLF score was developed in a derivation cohort (n = 480) and was validated (n = 922).

RESULTS

The overall survival of ACLF patients at 28 days was 51.7%, with a median of 26.3 days. Five baseline variables, total bilirubin, creatinine, serum lactate, INR and hepatic encephalopathy, were found to be independent predictors of mortality, with AUROC in derivation and validation cohorts being 0.80 and 0.78, respectively. AARC-ACLF score (range 5-15) was found to be superior to MELD and CLIF SOFA scores in predicting mortality with an AUROC of 0.80. The point scores were categorized into grades of liver failure (Gr I: 5-7; II: 8-10; and III: 11-15 points) with 28-day cumulative mortalities of 12.7, 44.5 and 85.9%, respectively. The mortality risk could be dynamically calculated as, with each unit increase in AARC-ACLF score above 10, the risk increased by 20%. A score of ≥11 at baseline or persisting in the first week was often seen among nonsurvivors (p = 0.001).

CONCLUSIONS

The AARC-ACLF score is easy to use, dynamic and reliable, and superior to the existing prediction models. It can reliably predict the need for interventions, such as liver transplant, within the first week.

A 3D alcoholic liver disease model on a chip

Alcohol is one of the main causes of liver diseases, and the development of alcoholic liver disease (ALD) treatment methods has been one of the hottest issues. For this purpose, development of in vitro models mimicking the in vivo physiology is one of the critical requirements, and they help to determine the disease mechanisms and to discover the treatment method. Herein, a three-dimensional (3D) ALD model was developed and its superior features in mimicking the in vivo condition were demonstrated. A spheroid-based microfluidic chip was employed for the development of the 3D in vitro model of ALD progression. We co-cultured rat primary hepatocytes and hepatic stellate cells (HSCs) in a fluidic chip to investigate the role of HSCs in the recovery of liver with ALD. An interstitial level of flow derived by an osmotic pump was applied to the chip to provide in vivo mimicking of fluid activity. Using this in vitro tool, we were able to observe structural changes and decreased hepatic functions with the increase in ethanol concentration. The recovery process of liver injured by alcohol was observed by providing fresh culture medium to the damaged 3D liver tissue for few days. A reversibly- and irreversibly-injured ALD model was established. The proposed model can not only be used for the research of alcoholic disease mechanism, but also has the potential for use in studies of hepatotoxicity and drug screening applications.

Survival Benefit of Early Cancer Detection Through Regular Endoscopic Screening for De Novo Gastric and Colorectal Cancers in Korean Liver Transplant Recipients

BACKGROUND

De novo malignancy is not uncommon after liver transplantation (LT). Gastric cancer is one of the most common malignancies in both the Korean general population and LT recipients, and colorectal cancer prevalence is gradually increasing.

METHODS

Among 3690 adult recipients who underwent LT from January 1999 and December 2013, the screening patterns and prognosis of 26 cases of gastric cancer and 22 cases of colorectal cancer were analyzed.

RESULTS

For gastric cancer, the mean patient age was 54.6 ± 6.2 years at LT and 59.5 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 60.2 ± 29.8 months. Patients were divided into regular (n = 18) and non-regular (n = 8) screening groups, with early cancer found in 14 and 0 patients; their 2-year survival rates after cancer diagnosis were 93.1% and 33.3% (P = .006), respectively. Endoscopic resection was successfully performed in 8 patients, all in the regular screening group. For colorectal cancer, the mean patient age was 53.3 ± 6.1 years at LT and 58.1 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 54.3 ± 38.0 months. Patients were divided into regular (n = 19) and non-regular (n = 3) screening groups, with early cancer found in 12 and 0 patients; their 2-year survival rates after cancer diagnosis of 92.3% and 33.3% (P = .003), respectively. Endoscopic resection was successfully performed in 6 patients, all in the regular screening group.

CONCLUSIONS

LT recipients are strongly advised to undergo regular screening studies for various de novo malignancies, especially cancers common in the general population. Regular endoscopic screening contributes to the timely detection of gastric and colorectal cancers, improving post-treatment survival outcomes.

Routine endoscopic screening for synchronous esophageal neoplasm in patients with head and neck squamous cell carcinoma: a prospective study

Early detection of synchronous esophageal squamous cell neoplasm (ESCN) in head and neck squamous cell carcinoma (HNSCC) patients can significantly affect their prognosis. We investigated the prevalence of synchronous ESCN and the risk factors for developing ESCN in patients with HNSCC, and evaluated the effect of routine endoscopic screening in these patients. Subjects who were diagnosed as HNSCC from May 2010 to January 2014 were eligible. All patients underwent conventional white light endoscopic examinations with narrow band imaging and Lugol chromoendoscopy. Among 458 subjects screened, 28 synchronous ESCN were detected in 24 patients (5.2%). The prevalence of ESCN was greatest in patients with hypopharyngeal cancer (20.9%). In multivariate analysis, pyriform sinus involvement was independent risk factor for developing synchronous ESCN (odds ratio 171.2, P < 0.001). During the follow-up period (median, 24 months), the 3-year overall survival rates was significantly lower in patients with ESCN than in patients without ESCN (54.2% vs. 78.3%, P = 0.0013). Routine endoscopic screening for detecting synchronous ESCN should be recommended for patients with HNSCC, especially those with pyriform sinus involvement.

Reproducible Construction of Surface Tension-Mediated Honeycomb Concave Microwell Arrays for Engineering of 3D Microtissues with Minimal Cell Loss

The creation of engineered 3D microtissues has attracted prodigious interest because of the fact that this microtissue structure is able to mimic in vivo environments. Such microtissues can be applied extensively in the fields of regenerative medicine and tissue engineering, as well as in drug and toxicity screening. Here, we develop a novel method of fabricating a large number of dense honeycomb concave microwells via surface tension-mediated self-construction. More specifically, in order to control the curvature and shape of the concavity in a precise and reproducible manner, a custom-made jig system was designed and fabricated. By applying a pre-set force using the jig system, the shape of the honeycomb concave well was precisely and uniformly controlled, despite the fact that wells were densely packed. The thin wall between the honeycomb wells enables the minimization of cell loss during the cell-seeding process. To evaluate the performance of the honeycomb microwell array, rat hepatocytes were seeded, and spheroids were successfully formed with uniform shape and size. Liver-specific functions such as albumin secretion and cytochrome P450 were subsequently analyzed. The proposed method of fabricating honeycomb concave wells is cost-effective, simple, and reproducible. The honeycomb well array can produce multiple spheroids with minimal cell loss, and can lead to significant contributions in tissue engineering and organ regeneration.

Subjective apnoea symptoms are associated with daytime sleepiness in patients with moderate and severe obstructive sleep apnoea: a retrospective study

OBJECTIVES

Most previous studies have failed to show a relation between daytime sleepiness and apnoea severity in patients with obstructive sleep apnoea (OSA). We determined the relation between daytime sleepiness and subjective and objective apnoea severity in newly diagnosed patients with moderate-to-severe OSA.

DESIGN

Retrospective cross-sectional study.

SETTING

Tertiary referral centre.

PARTICIPANTS

A total of 559 adults with newly diagnosed moderate and severe OSA.

MAIN OUTCOME MEASURES

Daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). Subjective and objective apnoea severities were assessed using the Sleep Breathing Scale (SBS) and polysomnography respectively. Sleep quality and depressive symptoms were evaluated using Medical Outcomes Study-Sleep Scale and Beck Depression Inventory (BDI) respectively.

RESULTS

The mean ESS score was 9.8 (SD 5.0). ESS score was correlated with SBS score (P < 0.001), apnoea-hypopnoea index (AHI) (P = 0.027), minimal oxygen saturation (MinSaO2 ) (P = 0.021), body mass index (BMI) (P = 0.007) and BDI score (P < 0.001). Linear regression analysis showed that higher SBS (P = 0.005) and BDI scores (P < 0.001) were associated with higher ESS score after controlling for gender, BMI and AHI. Apnoea-hypopnoea index, MinSaO2 and BMI were not independently related to ESS score.

CONCLUSIONS

Daytime sleepiness was related to subjective OSA symptoms but not objective apnoea severity measured by polysomnography in patients with moderate-to-severe OSA. These findings suggest the usefulness of the subjective apnoea severity as an indicator of OSA disease severity.

Multi-modal imaging and cancer therapy using lanthanide oxide nanoparticles: current status and perspectives

Biomedical imaging is an essential tool for diagnosis and therapy of diseases such as cancers. It is likely true that medicine has developed with biomedical imaging methods. Sensitivity and resolution of biomedical imaging methods can be improved with imaging agents. Furthermore, it will be ideal if imaging agents could be also used as therapeutic agents. Therefore, one dose can be used for both diagnosis and therapy of diseases (i.e., theragnosis). This will simplify medical treatment of diseases, and will be also a benefit to patients. Mixed (Ln(1x)Ln(2y)O3, x + y = 2) or unmixed (Ln2O3) lanthanide (Ln) oxide nanoparticles (Ln = Eu, Gd, Dy, Tb, Ho, Er) are potential multi-modal imaging and cancer therapeutic agents. The lanthanides have a variety of magnetic and optical properties, useful for magnetic resonance imaging (MRI) and fluorescent imaging (FI), respectively. They also highly attenuate X-ray beam, useful for X-ray computed tomography (CT). In addition gadolinium-157 ((157)Gd) has the highest thermal neutron capture cross section among stable radionuclides, useful for gadolinium neutron capture therapy (GdNCT). Therefore, mixed or unmixed lanthanide oxide nanoparticles can be used for multi-modal imaging methods (i.e., MRI-FI, MRI-CT, CT-FI, and MRICT- FI) and cancer therapy (i.e., GdNCT). Since mixed or unmixed lanthanide oxide nanoparticles are single-phase and solid-state, they can be easily synthesized, and are compact and robust, which will be beneficial to biomedical applications. In this review physical properties of the lanthanides, synthesis, characterizations, multi-modal imagings, and cancer therapy of mixed and unmixed lanthanide oxide nanoparticles are discussed.

The effect of age on the key parameters in the Chicago classification: a study using high-resolution esophageal manometry in asymptomatic normal individuals

BACKGROUND

High-resolution manometry using the Chicago classification, which utilizes parameters including integrated relaxation pressure (IRP), distal contractile integral (DCI), and contractile front velocity (CFV), shows better diagnostic ability than previous conventional criteria. However, the current normal cut-off values for the Chicago classification are based on individuals aged 19-48 years and do not include older people. Here, we aimed to assess the normal values for the Chicago classification in individuals aged 20-67 years and compare the parameters across age groups.

METHODS

Fifty-four asymptomatic healthy individuals (27 male and 27 female; age range. 20-67 years) were prospectively enrolled. To evaluate the effect of age and sex on manometric profiles, we attempted to enroll equal numbers of male and female subjects for each decade. Manometry was performed in both the supine and sitting positions.

KEY RESULTS

The distal latency (DL) was significantly shorter with increasing age in both measurement positions. Furthermore, IRP was significantly higher with increasing age in both positions. Spearman's ranked correlation coefficient analysis indicated that DCI and IRP in both positions were positively correlated with age.

CONCLUSIONS & INFERENCES

Age affects the key parameters currently used in the Chicago classification, including IRP, DCI, and DL. Larger prospective studies with older subjects are needed to determine the age-related normal values for the Chicago classification system.

Genetic testing in inherited polyposis syndromes - how and why?

There have been recent advances in genetic testing enabling accurate diagnosis of polyposis syndromes by identifying causative gene mutations, which is essential in the management of individuals with polyposis syndrome and predictive genetic testing of their extended families. There are some similarities in clinical presentation of various polyposis syndromes, which may pose a challenge to diagnosis. In this review, we discuss the clinical presentation of the main polyposis syndromes and the process of genetic testing, including the latest advancement and future of genetic testing. We aim to reiterate the importance of genetic testing in the management of polyposis syndromes, potential pitfalls associated with genetic testing and recommendations for healthcare professionals involved with the care of polyposis patients.

Alopecia in three macaque species housed in a laboratory environment

Alopecia is a persistent problem in captive macaque populations and despite recent interest, no factors have been identified that can unequivocally explain the presence of alopecia in a majority of cases. Seasonal, demographic, and environmental factors have been identified as affecting alopecia presentation in rhesus macaques, the most widely studied macaque species. However, few studies have investigated alopecia rates in other macaque species. We report alopecia scores over a period of 12 months for three macaque species (Macaca nemestrina, M. mulatta, and M. fascicularis) housed at three indoor facilities within the Washington National Primate Research Center (WaNPRC) in Seattle. Clear species differences emerged with cynomolgus (M. fascicularis) showing the lowest alopecia rates and pigtails (M. nemestrina) the highest rates. Further analysis of pigtail and rhesus (M. mulatta) macaques revealed that sex effects were apparent for rhesus but not pigtails. Age and seasonal effects were evident for both species. In contrast to previous reports, we found that older animals (over 10 years of age) had improved alopecia scores in comparison to younger adults. This is the first report on alopecia rates in pigtail macaques and the first comparison of alopecia scores in pigtail, cynomolgus, and rhesus macaques housed under similar conditions.

Lost therapeutic potential of monocyte-derived dendritic cells through lost tissue homing: stable restoration of gut specificity with retinoic acid

Human monocyte-derived dendritic cells (DC) (MoDC) are utilized for immunotherapy. However, in-vitro immunological effects are often not mirrored in vivo. We studied the tissue-homing potential of MoDC. Circulating monocytes and DC expressed different tissue-homing markers and, during in-vitro development of MoDC, homing marker expression was lost resulting in a 'homeless' phenotype. Retinoic acid (RA) induced gut-homing markers (β7 and CCR9) and a regulatory phenotype and function [decreased human leucocyte antigen D-related (HLA-DR) and increased ILT3 and fluorescein isothiocyanate (FITC-dextran uptake) in MoDC]. RA-MoDC were less stimulatory and primed conditioned T cells with a gut-homing profile (β7(+)CLA(-)). Unlike the normal intestinal microenvironment, that from inflamed colon of ulcerative colitis (UC) patients did not induce regulatory properties in MoDC. However, RA-MoDC maintained their regulatory gut-specific properties even in the presence of UC microenvironment. Therefore, MoDC may be ineffectual for immunotherapy because they lack tissue-homing and tissue-imprinting specificity. However, MoDC rehabilitation with gut-homing potential by RA could be useful in promoting immunotherapy in pathologies such as UC.

Endoscopic submucosal dissection for sessile, nonampullary duodenal adenomas

Although endoscopic submucosal dissection (ESD) is increasingly utilized to treat early neoplasms of the gastrointestinal tract, its use for duodenal neoplasms is limited by the thin wall and narrow lumen of the duodenum. We have reviewed cases where ESD was used to treat sessile, nonampullary duodenal neoplasms. To do this, we retrospectively reviewed the medical records of patients treated with ESD for adenomas of the duodenum from January 2001 to December 2010, assessing the curative outcomes and complication rates. A total of 14 cases were reviewed. Mean patient age was 56.4 years. The mean size of tumors and mean size of the specimens were 17.1 mm and 26.4 mm, respectively. The en bloc resection rate with ESD was 78.6%, and the complete (R0) resection rate was 85.7%. No patient in the study experienced major bleeding. However, second-look endoscopy revealed minor bleeding requiring endoscopic homeostasis in one case (7.1%). Perforations were observed in five cases (35.7%). Two of the five patients with perforation underwent surgery. The ESD methods yielded acceptable curative resection rates for duodenal adenomas, although ESD was associated with a higher rate of perforation. Therefore, duodenal ESD should be performed with care and only in selected patients to avoid serious complications.

Resolution of adefovir-related nephrotoxicity by adefovir dose-reduction in patients with chronic hepatitis B

BACKGROUND

Chronic hepatitis B patients (CHB) treated with adefovir were followed up to evaluate nephrotoxicity and its outcome.

AIM

To assess the incidence of renal dysfunction during adefovir therapy in Asian patients and factors associated with it, and evaluate strategies to improve adefovir-related renal dysfunction and their impact on viral suppression.

METHODS

Chronic hepatitis B clinic patients from a tertiary hospital on adefovir treatment, with their clinical and laboratory parameters were extracted from the hospital electronic clinical database in an observational study design. Patients were excluded if they had liver/renal transplant, baseline renal impairment or were on dialysis. Adefovir-related renal dysfunction was defined as adefovir-related abnormal serum creatinine (ARASC) > 125 μmol/L (males), >90 μmol/L (females); adefovir-related abnormal GFR <60 mL/min; and adefovir-related increased serum creatinine >0.5 mg/dL, without other known causes of nephrotoxicity.

RESULTS

A total of 271/383 adefovir-treated patients were suitable for analysis and 33(12%) patients developed abnormal serum creatinine. Cumulative increase in proportion of patients with ARASC was 33.8% and GFR ≤60 mL/min was 38.3% by 6 years, while serum creatinine increase ≥0.5 mg/dL was 21.48% by 5 years. Using multivariate analysis, the only independent baseline predictor of ARASC was GFR ≤76.1 mL/min. Patients who had ARASC had similar levels of viral suppression to those who did not have ARASC. Those who had ARASC either continued adefovir (24%), switched therapy (24%) or had adefovir dose reduction (52%). ARASC resolved and GFR normalised in almost all patients after either switching therapy or reducing adefovir dose, with no difference between the two strategies (P = 0.737). Those with adefovir dose reduction had no significant increase in HBV DNA (P = 0.170).

CONCLUSIONS

Adefovir-related renal dysfunction occurred in a significant number of adefovir-treated patients, but reduction of the dose led to renal improvement without compromising treatment efficacy.

Natural course of noncurative endoscopic resection of differentiated early gastric cancer

BACKGROUND AND STUDY AIMS

Following noncurative endoscopic resection of early gastric cancer (EGC), the patient should be observed when the underlying disease is severe, the patient is elderly, or the patient refuses further treatment. The aim of this study was to analyze the clinical outcomes of patients with differentiated EGC who underwent noncurative endoscopic resection without additional treatment.

PATIENTS AND METHODS

Included patients underwent noncurative endoscopic resection for differentiated EGC without additional treatment at the Asan Medical Center between July 1994 and January 2009. Clinical and oncological outcomes were analyzed.

RESULTS

A total of 159 patients were included in the analysis. The median follow-up period was 33 months (interquartile range [IQR] 22 - 52 months). In total, 40 patients died (25.2 %) - 3 due to stomach cancer, 34 due to other causes, and 3 from unknown causes; the median survival time after endoscopic treatment for these patients was 27.5 months (IQR 13.8 - 48.3 months). Multivariate analysis showed that the rates of underlying disease (P < 0.001) and lymphovascular invasion (P = 0.005) were higher among the 40 patients who died than among the 119 survivors. The overall 3-  and 5-year survival rates were 82.9 % and 77.1 %, respectively; the rates of the patients with lymphovascular invasion were 61.9 % and 42.4 %, respectively, and the rates of patients without lymphovascular invasion were 86.1 % and 81.8 %, respectively (P < 0.001).

CONCLUSIONS

Additional treatment provides fewer benefits to patients who do not have long life expectancies. Additional surgery can be considered for patients with lymphovascular invasion because of its high mortality rate; however, the benefits and risks of surgery should be considered carefully.

Spontaneous bilateral compartment syndrome of the legs: A case report and review of the literature

INTRODUCTION

Bilateral acute compartment syndrome of the legs is a rare presentation requiring emergent surgical intervention.

PRESENTATION OF CASE

We report the case of 41-year-old woman who presented with acute bilateral compartment syndrome of the legs, complicated by rhabdomyolysis and acute renal failure.

DISCUSSION

There are very few previously reported cases of bilateral compartment syndrome of the legs. In the present case, despite any clear causative factor, we suggest that the aetiology is related to inadvertent posture during sleep.

CONCLUSION

The diagnosis of acute bilateral compartment syndrome of the legs requires a high index of suspicion, particularly in the absence of obvious aetiology. A successful outcome can be achieved with early diagnosis, prompt surgical intervention and a multidisciplinary approach.

Formation of hybrid structures: copper oxide nanocrystals templated on ultralong copper nanowires for open network sensing at room temperature

A facile large-scale synthesis approach for producing intrinsically p-type nanowires with uniform coverage of nanocrystals to form a highly interconnected porous nanowire network is of great demand for p-type sensing. Here, we have demonstrated synthesis of a very high aspect ratio (10(2)-10(5)) open network of interconnected hybrid nanocrystals-nanowire copper and copper oxide nanomaterials. The copper nanowire scaffold is employed to realize a porous and highly interconnected network of hybrid metal-metal oxide nanocrystal-nanowire structures. The structural and composition tunability of the hybrid nanomaterials is demonstrated. The hybrid copper-copper oxide nanowires exhibit enhanced gas/light sensing properties without any operating temperature. This may be attributed to enhanced medium diffusion due to the porous network of highly interconnected nanocrystal-nanowire structures.

Association of the interferon-γ gene (CA)n repeat polymorphism with endometriosis

OBJECTIVE

To investigate whether the interferon-γ (IFN-γ) gene (CA)(n) repeat polymorphism is associated with susceptibility to endometriosis.

DESIGN

Case-control study.

SETTING

University Department of Obstetrics and Gynaecology.

POPULATION

Women with (n = 622) and without (n = 442) endometriosis.

METHODS

Genotyping was performed by fluorescent polymerase chain reaction (PCR) and gene-scan analysis.

MAIN OUTCOME MEASURES

Genotype distribution and allele frequency of the dinucleotide (CA)(n) repeat polymorphism in the IFN-γ gene.

RESULTS

Seven alleles (12-18 repeats) of the IFN-γ gene (CA)(n) repeat polymorphism were found. In both patients with endometriosis and controls the most common allele was composed of 13 repeats, followed by an allele of 15 repeats, and then by an allele of 12 repeats. Patients with endometriosis had a significantly higher incidence of genotypes with alleles composed of fewer repeats (12-13 repeats), compared with the controls (92.0 versus 84.4%, respectively, P < 001).

CONCLUSIONS

Our results suggest that the (CA)(n) repeat polymorphism in the IFN-γ gene may be associated with a risk of endometriosis in the South Korean population.

Transnasal endoscope-assisted endoscopic submucosal dissection for gastric adenoma and early gastric cancer in the pyloric area: a case series

Endoscopic submucosal dissection (ESD) is an important therapeutic option for gastric adenoma and early gastric cancer (EGC). However, ESD is technically difficult when lesions are located in the pyloric area. Our aim was to introduce the transnasal endoscope-assisted ESD method, which provides for excellent cutting-line visualization through control of submucosal traction. A total of eight patients with gastric adenoma or EGC located in the pyloric area were consecutively enrolled. A primary operating endoscope was used to perform marking, incision, submucosal dissection, and hemostasis, while a thinner, transnasal endoscope operated by a second endoscopist was used to retract connective submucosal tissue to provide cutting-line visualization using V-shaped grasping forceps. En bloc resection was achieved in all eight cases, as was complete resection. The median longest lesion diameter was 19 mm (range: 12-25 mm), and the median procedure time was 37.5 minutes (range: 29-59 minutes). There were no incidents of significant bleeding or perforation. Transnasal endoscope-assisted ESD was useful for treating gastric neoplasms in the pyloric area. The procedure was relatively easy and safe, provided excellent visualization through tissue retraction, and allowed for complete en bloc resection.

Characteristics of color optical shutter with dye-doped polymer network liquid crystal

The optical properties and the theoretical prediction of color optical shutter with dye-doped polymer network liquid crystal (PNLC) were investigated. The view-angle dependence of reflectance according to the bias conditions showed distinctive characteristics, which could be explained from the effects of dye absorption and path length. It was also shown that the thickness dependence of reflectance was strongly influenced by the light-scattering coefficient. Our experimental results matched up well with the theoretical prediction based on the light scattering of liquid crystals in polymer network and the absorption of dichroic dye. This work indicates potential to improve the optical device using dye-doped liquid crystal-polymer composite.

Wear performance of self-mating contact pairs of TiN and TiAlN coatings on orthopedic grade Ti-6Al-4V

Both titanium nitride (TiN) and titanium aluminum nitride (TiAlN) have shown great wear resistance potential in metallic medical devices as protective, hard thin film coatings. In the present study, the effects of TiN and TiAlN coating layers on the wear performance of Ti-6Al-4V were compared and analyzed. TiN and TiAlN coatings with a thickness of 3 microm were deposited by a cathodic vacuum arc ion plating technique on the surface of Ti-6Al-4V. Wear tests were conducted by using a pin-on-disk-type tribotester with a point contact self-mating pair in a linear reciprocal motion. A sliding distance of 20 mm per cycle at 1 Hz was used under a load of 15 N under ambient conditions with no lubricant. The wear resistance of TiN and TiAlN coatings is superior to that of uncoated Ti-6Al-4V at the early stage of sliding contact. Until a measurable amount of wear was detected, the number of sliding cycles of the TiAlN coating pair was longer than TiN. After the first detection of wear from the coating layers, the rate of wear of the TiN coating pairs was significantly higher than that of TiAlN (p < 0.05), and it was close to that of the uncoated pairs. In conclusion, the TiAlN coating is superior to TiN from the viewpoint of wear resistance under the test conditions used in this study.

Case report: Imaging features of perianal leiomyoma

A leiomyoma is a benign mesenchymal neoplasm that usually develops where smooth muscle is present. In this report, we present a rare case of perianal leiomyoma. The external anal sphincter was stretched over the surface of the leiomyoma and the internal anal sphincter was intact on surgery. It was confirmed as a deep soft-tissue leiomyoma on pathology. We describe the ultrasonographic and MRI findings of a rare case of perianal leiomyoma, together with differential diagnoses.

Electronic structure of pyrochlore Cd(2)Re(2)O(7)

Detailed band structure calculations have been performed for Cd(2)Re(2)O(7) in high-, middle- and low-temperature (T) phases. The calculations are based on the observed lattice structures from x-ray diffraction measurements. The spin-orbit interaction is incorporated self-consistently in both the generalized gradient approximation (GGA) and the GGA plus Hubbard U (GGA+U) approaches. It is found that the on-site U has negligible effects on the Re 5d band structures; therefore both the GGA and GGA+U Re 5d band energies agree well with the observed O K-edge x-ray absorption spectroscopy (XAS) spectrum, whereas the Cd 4d band energy observed from photoemission spectroscopy can only be correctly reproduced by GGA+U calculations, indicating the relatively itinerant Re 5d and localized Cd 4d electrons. On the other hand, the spin-orbit coupling gives rise to nontrivial spin and orbital magnetic moments for the middle- T phase. Most unexpectedly, we found that the low- T phase exhibits quasi-two-dimensional Fermi surfaces. The calculated carrier numbers for the three phases are, at least qualitatively, consistent with the measured Hall coefficient.

Aroma-active components of Lycii fructus (kukija)

The fruit of Lycii fructus has been used as a tonic medicine and a long-term healthy food without side effect in Asia. An increase in the demand for natural healthy food, L. fructus has been thought as a source of healthy foods. For its value adding, its character impact aromas were isolated by using direct solvent extraction with vacuum transfer and identified by using gas chromatography olfactometry (GC-O) and GC-mass spectrometry (GC-MS). Thirty-three odor compounds were sniffed at GC-O, each trial equipped with DB-5MS and HP-WAX capillary column. The most contributing odor compounds in L. fructus were (E)-2-heptenal (green, mushroomy), 1-heptanol (planty, oily), hexanal (planty), 3-octanol (mushroomy, planty), 1-octen-3-ol (mushroomy), and 2-methyl-2-butenoic acid (pungent, planty), which might be produced by enzymatic oxidation and/or oxidation of lipids and carotenes, resulting in undesirable aromas.

Minimal hepatic encephalopathy runs a fluctuating course: results from a three-year prospective cohort follow-up study

INTRODUCTION

Minimal hepatic encephalopathy (mHE) has been reported in up to 84 percent of cirrhotics. The natural history of mHE has not been well-described. We designed a three-year prospective cohort study to determine the prevalence and natural history of mHE among cirrhotic patients.

METHODS

The patient cohort comprising 62 consecutive outpatients with cirrhosis were assessed at baseline and followed-up with a repeat assessment three years later. The assessments include: (1) Neuropsychometric analysis (digit-symbol substitution test, block-design test, number-connection test A); (2) Clinical, biochemical assessment; and (3) Quality of life (QOL) assessment (abbreviated sickness impact profile).

RESULTS

Baseline characteristics were: age 52.9 +/- 11.0 years; Child's A:B:C was 46:14:2. mHE was detected in 33.9 percent of the cohort. Older age, a higher Child-Pugh score and female gender were independently associated with mHE. mHE was associated with a poorer QOL. Follow-up assessment three years later showed that seven patients had died, while six were lost to follow-up; these patients had significantly higher baseline Child's scores. Of the remaining patients, 36/49 (73 percent) agreed to a repeat evaluation. In this group, none had mHE. QOL remained impaired despite the resolution of mHE.

CONCLUSION

It has been shown for the first time that mHE can revert to a normal state in a significant proportion of patients with well-compensated cirrhosis.

Unchanging trend of esophagogastric junction adenocarcinoma in Korea: experience at a single institution based on Siewert's classification

The incidence of adenocarcinoma of the esophagogastric junction (AEG) has been increasing in Western countries. It is unclear, however, whether similar changes are occurring in Asia. We therefore investigated the incidence of AEG in Korea, and assessed the clinical characteristics of three types of AEG based on Siewert's classification. We retrospectively reviewed the medical records of 16 811 patients diagnosed with esophageal squamous cell carcinoma (ESC, n= 1450) or gastric noncardiac adenocarcinoma (GNCA, n= 14 751) between 1992 and 2006. The patients were divided into three 5-year cohorts (cohort A [1992-1996], n= 2734, cohort B [1997-2001], n= 5727, and cohort C [2002-2006], n= 8350), and the ratios of AEG (n= 610) to non-AEG (ESC and GNCA) in each cohort were compared. Using Siewert's classification, the tumors were categorized into one of three types, and patient demographic features and 5-year survival rates were compared. The ratio of AEG to non-AEG cases did not change over time (0.037, 0.034, and 0.039 for cohorts A, B, and C, respectively; P= 0.40). Of the 610 patients with AEG, 23 (3.7%) had type 1 tumors, 47 (7.7%) had type 2, and 540 (88.5%) had type 3. The 5-year survival rate of patients with type 1 AEG was much lower (4.8 +/- 4.7%) than that of those with type 2 (47.9 +/- 7.8%) and type 3 (47.4 +/- 2.5%) tumors. Unlike in Western countries, the ratio of AEG to non-AEG cases has not increased over time in Korea. Type 1 AEG was rarer and associated with a more unfavorable prognosis in Korea than in Western countries.

Mucinous tubular and spindle cell carcinoma with Fuhrman nuclear grade 3: a histological, immunohistochemical, ultrastructural and FISH study

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney generally shows low nuclear grade. MTSCC with high nuclear grade is relatively rare. In this article, we report two cases of MTSCC with Fuhrman grade 3. One case occurred in a 57-year-old Japanese female and the second case in a 49-year-old Caucasian female. Histologically, the tumors were composed of neoplastic cells with cuboidal or columnar and spindle morphology, and Fuhrman nuclear grade 3. The myxoid stroma was also observed. This stroma was positive for Alcian blue stain. Immunohistochemically, neoplastic cells of both cases were positive for AMACR, but negative for CD10 and RCC Ma. Ultrastructurally, tumorous cells of one case contained numerous mitochondria. In FISH analysis, many neoplastic cells of both cases demonstrated monosomy of chromosomes 15 and 22 and disomy of chromosomes 7 and 17. One of the two patients died of respiratory failure due to pleuritis carcinomatosa 48 months postoperatively. Finally, the pathologist should recognize that high grade MTSCC exists despite its rare frequency. FISH analysis may be helpful in establishing the diagnosis of this entity. Furthermore, we present the first report of a patient with MTSCC dying of distant metastasis.

Association of TIMP-4 gene polymorphism with the risk of osteoarthritis in the Korean population

Due to an imbalance in the MMP:TIMP ratio determined a tissue damage in arthritis, it is hypothesized that polymorphic variations of the TIMP genes are associated with regulation of the MMP:TIMP balance. To test this hypothesis, the presence of single nucleotide polymorphisms (SNPs) located in the human TIMP-2 and TIMP-4 genes was confirmed in the Korean RA and OA patients. We performed a case-control study comprising 109 unrelated Korean OA patients, 177 unrelated Korean RA patients and 175 healthy subjects. There were statistically significant differences in the genotype distribution and allele frequencies of the C/T polymorphism of TIMP-4 gene between OA and control groups (P = 0.0002 and P = 0.001, respectively). However, no significant association between TIMP-2 polymorphisms and OA was observed. Also, no difference was observed when allele or genotype frequencies of both TIMP-2 and TIMP-4 gene polymorphisms were compared between RA and controls. We demonstrated that the C/T polymorphism which is located on the 3'-untranslational regions of the TIMP-4 gene might be associated with susceptibility to OA patients.

Gastric schwannomas: radiological features with endoscopic and pathological correlation

AIM

To describe the radiological, endoscopic, and pathological findings of gastric schwannomas in 16 patients.

MATERIALS AND METHODS

The radiological, endoscopic, and pathological findings of 16 surgically proven cases of gastric schwannoma were retrospectively reviewed. All patients underwent computed tomography (CT) and four patients were evaluated with upper gastrointestinal series. Two radiologists reviewed the CT and upper gastrointestinal series images by consensus with regard to tumour size, contour, margin, and growth pattern, the presence or absence of ulcer, cystic change, and the CT enhancement pattern. Endoscopy was performed in eight of these 16 patients. Six patients underwent endoscopic ultrasonography. Pathological specimens were obtained from and reviewed in all 16 patients. Immunohistochemistry was performed for c-kit, CD34, smooth muscle actin, and S-100 protein.

RESULTS

On radiographic examination, gastric schwannomas appeared as submucosal tumours with the CT features of well-demarcated, homogeneous, and uncommonly ulcerated masses. Endoscopy with endoscopic ultrasonography demonstrated homogeneous, submucosal masses contiguous with the muscularis propria in all six examined cases. On pathological examination, gastric schwannomas appeared as well-circumscribed and homogeneous tumours in the muscularis propria and consisted microscopically of interlacing bundles of spindle cells. Strong positivity for S-100 protein was demonstrated in all 16 cases on immunohistochemistry.

CONCLUSION

Gastric schwannomas appear as submucosal tumours of the stomach and have well-demarcated and homogeneous features on CT, endoscopic ultrasonography, and gross pathology. Immunohistochemistry consistently reveals positivity for S-100 protein in the tumours.