Latent diffusion model-based MRI superresolution enhances mild cognitive impairment prognostication and Alzheimer's disease classification.

INTRODUCTION: Timely diagnosis and prognostication of Alzheimer's disease (AD) and mild cognitive impairment (MCI) are pivotal for effective intervention. Artificial intelligence (AI) in neuroradiology may aid in such appropriate diagnosis and prognostication. This study aimed to evaluate the potential of novel diffusion model-based AI for enhancing AD and MCI diagnosis through superresolution (SR) of brain magnetic resonance (MR) images. METHODS: 1.5T brain MR scans of patients with AD or MCI and healthy controls (NC) from Alzheimer's Disease Neuroimaging Initiative 1 (ADNI1) were superresolved to 3T using a novel diffusion model-based generative AI (d3T*) and a convolutional neural network-based model (c3T*). Comparisons of image quality to actual 1.5T and 3T MRI were conducted based on signal-to-noise ratio (SNR), naturalness image quality evaluator (NIQE), and Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE). Voxel-based volumetric analysis was then conducted to study whether 3T* images offered more accurate volumetry than 1.5T images. Binary and multiclass classifications of AD, MCI, and NC were conducted to evaluate whether 3T* images offered superior AD classification performance compared to actual 1.5T MRI. Moreover, CNN-based classifiers were used to predict conversion of MCI to AD, to evaluate the prognostication performance of 3T* images. The classification performances were evaluated using accuracy, sensitivity, specificity, F1 score, Matthews correlation coefficient (MCC), and area under the receiver-operating curves (AUROC). RESULTS: Analysis of variance (ANOVA) detected significant differences in image quality among the 1.5T, c3T*, d3T*, and 3T groups across all metrics. Both c3T* and d3T* showed superior image quality compared to 1.5T MRI in NIQE and BRISQUE with statistical significance. While the hippocampal volumes measured in 3T* and 3T images were not significantly different, the hippocampal volume measured in 1.5T images showed significant difference. 3T*-based AD classifications showed superior performance across all performance metrics compared to 1.5T-based AD classification. Classification performance between d3T* and actual 3T was not significantly different. 3T* images offered superior accuracy in predicting the conversion of MCI to AD than 1.5T images did. CONCLUSIONS: The diffusion model-based MRI SR enhances the resolution of brain MR images, significantly improving diagnostic and prognostic accuracy for AD and MCI. Superresolved 3T* images closely matched actual 3T MRIs in quality and volumetric accuracy, and notably improved the prediction performance of conversion from MCI to AD.

Field-calibrated magneto-optic sensor based on off-axis optical probing of intense magnetic fields.

We present a magneto-optic sensing system based on the "off-axis" optical probing technique to control the measurement sensitivity of magnets with various field strengths. The magnetic field is experimentally investigated in the absolute scale through a photonic calibration method with a standard electromagnet. Our all-dielectric magnetic field probe has a wide dynamic range (20 mT-3 T) with good responsivity and low probe invasiveness against the magnetic field being measured. Utilizing this magnetic-field-calibrated probing system, we obtain the magnetic field distribution of permanent magnets. Subsequently, we compare our results with numerical analyses to confirm the effectiveness of the probing system. Finally, we measure the intense magnetic field inside the bore of a 3.0-T clinical magnetic resonance imaging system with our probe.

Short-term changes of intraocular pressure and ocular perfusion pressure after intravitreal injection of bevacizumab or ranibizumab.

BACKGROUND: The aim of this study was to investigate the effect of intravitreal anti-vascular endothothelial growth factor (VEGF) injection on intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP). METHODS: MOPP results were obtained by measuring mean arterial pressure (MAP) and IOP just before the injection, immediately after the injection, at 30 min, 1 day, and 1 week after injection from 65 eyes of 42 patients. RESULTS: Pre-injection mean IOP was 16.66 ± 3.50 mmHg, and mean IOP was 43.81 ± 9.69 mmHg immediately after the injection, 17.57 ± 4.44 mmHg at 30 min, 15.00 ± 4.21 mmHg at 1 day, and 15.90 ± 3.63 mmHg at 1 week after the injection. Pre-injection mean MOPP was 46.39 ± 5.78 mmHg, and mean MOPP was 25.14 ± 8.79 mmHg immediately after the injection, 45.87 ± 6.31 mmHg at 30 min, 46.93 ± 6.25 mmHg at 1 day, and 46.50 ± 4.94 mmHg at 1 week after the injection. CONCLUSION: The instant increase in IOP by intravitreal anti-VEGF injection led to a transient decrease in MOPP. Based on this finding, the instant increase in IOP after intravitreal anti-VEGF injection does not significantly impair retinal blood flow.

Automated deep learning model for estimating intraoperative blood loss using gauze images.

The intraoperative estimated blood loss (EBL), an essential parameter for perioperative management, has been evaluated by manually weighing blood in gauze and suction bottles, a process both time-consuming and labor-intensive. As the novel EBL prediction platform, we developed an automated deep learning EBL prediction model, utilizing the patch-wise crumpled state (P-W CS) of gauze images with texture analysis. The proposed algorithm was developed using animal data obtained from a porcine experiment and validated on human intraoperative data prospectively collected from 102 laparoscopic gastric cancer surgeries. The EBL prediction model involves gauze area detection and subsequent EBL regression based on the detected areas, with each stage optimized through comparative model performance evaluations. The selected gauze detection model demonstrated a sensitivity of 96.5% and a specificity of 98.0%. Based on this detection model, the performance of EBL regression stage models was compared. Comparative evaluations revealed that our P-W CS-based model outperforms others, including one reliant on convolutional neural networks and another analyzing the gauze's overall crumpled state. The P-W CS-based model achieved a mean absolute error (MAE) of 0.25 g and a mean absolute percentage error (MAPE) of 7.26% in EBL regression. Additionally, per-patient assessment yielded an MAE of 0.58 g, indicating errors < 1 g/patient. In conclusion, our algorithm provides an objective standard and streamlined approach for EBL estimation during surgery without the need for perioperative approximation and additional tasks by humans. The robust performance of the model across varied surgical conditions emphasizes its clinical potential for real-world application.

A multimodal virtual vision platform as a next-generation vision system for a surgical robot.

Robot-assisted surgery platforms are utilized globally thanks to their stereoscopic vision systems and enhanced functional assistance. However, the necessity of ergonomic improvement for their use by surgeons has been increased. In surgical robots, issues with chronic fatigue exist owing to the fixed posture of the conventional stereo viewer (SV) vision system. A head-mounted display was adopted to alleviate the inconvenience, and a virtual vision platform (VVP) is proposed in this study. The VVP can provide various critical data, including medical images, vital signs, and patient records, in three-dimensional virtual reality space so that users can access medical information simultaneously. An availability of the VVP was investigated based on various user evaluations by surgeons and novices, who executed the given tasks and answered questionnaires. The performances of the SV and VVP were not significantly different; however, the craniovertebral angle of the VVP was 16.35° higher on average than that of the SV. Survey results regarding the VVP were positive; participants indicated that the optimal number of displays was six, preferring the 2 × 3 array. Reflecting the tendencies, the VVP can be a neoconceptual candidate to be customized for medical use, which opens a new prospect in a next-generation surgical robot.

Towards optimal design of patient isolation units in emergency rooms to prevent airborne virus transmission: From computational fluid dynamics to data-driven modeling.

BACKGROUND: Patient isolation units (PIUs) can be an effective method for effective infection control. Computational fluid dynamics (CFD) is commonly used for PIU design; however, optimizing this design requires extensive computational resources. Our study aims to provide data-driven models to determine the PIU settings, thereby promoting a more rapid design process. METHOD: Using CFD simulations, we evaluated various PIU parameters and room conditions to assess the impact of PIU installation on ventilation and isolation. We investigated particle dispersion from coughing subjects and airflow patterns. Machine-learning models were trained using CFD simulation data to estimate the performance and identify significant parameters. RESULTS: Physical isolation alone was insufficient to prevent the dispersion of smaller particles. However, a properly installed fan filter unit (FFU) generally enhanced the effectiveness of physical isolation. Ventilation and isolation performance under various conditions were predicted with a mean absolute percentage error of within 13%. The position of the FFU was found to be the most important factor affecting the PIU performance. CONCLUSION: Data-driven modeling based on CFD simulations can expedite the PIU design process by offering predictive capabilities and clarifying important performance factors. Reducing the time required to design a PIU is critical when a rapid response is required.

New profiles of posterior pole retinal thickness map in healthy Korean eyes measured by spectral-domain optical coherence tomography.

PURPOSE: To analyze posterior pole retinal thickness using the new Spectralis HRA + OCT protocol and compare two commercially available spectral-domain optical coherence tomography instruments (Spectralis HRA + OCT and Cirrus HD-OCT) in young healthy eyes. METHODS: Retinal thickness in 178 young healthy eyes was measured using the volume scan mode and Posterior Pole Asymmetry Analysis of the Spectralis HRA + OCT and the macular cube 512 × 128 protocol of the Cirrus HD-OCT. Topologic differences in posterior pole retinal thickness between the two spectral-domain optical coherence tomographies were compared, and the relationship between retinal thickness and age or refractive error/axial length was assessed. RESULTS: Mean retinal thickness measurements in all 9 Early Treatment Diabetic Retinopathy Study Report areas were significantly greater with the Spectralis HRA + OCT than with the Cirrus HD-OCT (P < 0.001). Retinal thickness measured with the new Spectralis HRA + OCT protocol positively correlated with refractive error (P < 0.05) and negatively correlated with axial length (P < 0.05), mainly in the temporal areas. As axial length increased and refractive error decreased, retinal thickness decreased significantly at the outer temporal areas compared with the nasal areas (P < 0.05). Foveal thickness measured with the Spectralis HRA + OCT correlated significantly with refractive error (r = -0.151; P = 0.022) and axial length (r = 0.352; P < 0.001). CONCLUSION: Posterior pole retinal thickness measurements in young healthy eyes should provide more detailed standard values for diagnosing and managing retinal disease.

Association between fundus autofluorescence and visual outcome in surgically closed macular holes.

PURPOSE: To investigate the association between fundus autofluorescence (FAF) and visual acuity, recovery of foveal microstructure, and FAF in surgically closed macular holes. METHODS: Twenty-six eyes with surgically closed macular hole were classified into two groups based on foveal FAF: normal autofluorescence (NAF) or increased autofluorescence (IAF). The association between foveal FAF and visual acuity was analyzed. In addition, we examined the relationship between recovery of the foveal microstructure assessed by spectral domain optical coherence tomography and FAF after macular hole surgery. RESULTS: At 1 month and 6 months after surgery, there were 9 NAF eyes and 17 IAF eyes. There were no differences between NAF and IAF eyes at 1 month and 6 months after surgery. Preoperative best-corrected visual acuity (logarithm of the minimum angle of resolution) did not differ between groups. Best-corrected visual acuity was significantly higher in the NAF group than in the IAF group at 1 month postoperatively (0.59 ± 0.34 vs. 0.91 ± 0.36, P = 0.044) and tended to be higher at 6 months (0.37 ± 0.38 vs. 0.69 ± 0.53, P = 0.126). Restoration of photoreceptor external limiting membrane differed significantly in 8 NAF eyes (89%) and 4 IAF eyes (24%) at postoperation 1 month (P = 0.001). After 6 months, external limiting membrane was restored in all 9 NAF eyes (100%) and in only 11 IAF eyes (65%) (P = 0.042). CONCLUSION: Fundus autofluorescence findings observed in surgically closed macular holes correlated with visual improvement and photoreceptor status. Eyes with visual improvement had restoration of normal foveal autofluorescence and retinal microstructure, whereas eyes with persistent foveal hyperautofluorescence did not achieve complete restoration of the retinal microstructure, and visual improvement was not as significant.

Evaluating diagnostic content of AI-generated chest radiography: A multi-center visual Turing test.

BACKGROUND: Accurate interpretation of chest radiographs requires years of medical training, and many countries face a shortage of medical professionals to meet such requirements. Recent advancements in artificial intelligence (AI) have aided diagnoses; however, their performance is often limited due to data imbalance. The aim of this study was to augment imbalanced medical data using generative adversarial networks (GANs) and evaluate the clinical quality of the generated images via a multi-center visual Turing test. METHODS: Using six chest radiograph datasets, (MIMIC, CheXPert, CXR8, JSRT, VBD, and OpenI), starGAN v2 generated chest radiographs with specific pathologies. Five board-certified radiologists from three university hospitals, each with at least five years of clinical experience, evaluated the image quality through a visual Turing test. Further evaluations were performed to investigate whether GAN augmentation enhanced the convolutional neural network (CNN) classifier performances. RESULTS: In terms of identifying GAN images as artificial, there was no significant difference in the sensitivity between radiologists and random guessing (result of radiologists: 147/275 (53.5%) vs result of random guessing: 137.5/275, (50%); p = .284). GAN augmentation enhanced CNN classifier performance by 11.7%. CONCLUSION: Radiologists effectively classified chest pathologies with synthesized radiographs, suggesting that the images contained adequate clinical information. Furthermore, GAN augmentation enhanced CNN performance, providing a bypass to overcome data imbalance in medical AI training. CNN based methods rely on the amount and quality of training data; the present study showed that GAN augmentation could effectively augment training data for medical AI.

Atypical vitelliform macular dystrophy misdiagnosed as chronic central serous chorioretinopathy: case reports.

BACKGROUND: To report two cases of atypical vitelliform macular dystrophy misdiagnosed as chronic central serous chorioretinopathy. CASE PRESENTATION: Two patients with incidentally discovered abnormalities of the retina without specific symptoms were referred to our hospital for consultation. Bilateral macula atrophic lesions were observed and optical coherence tomography revealed serous retinal detachment in the macula. Fluorescein angiography showed multiple leakages around the central hypofluorescent area and indocyanine green angiography showed partially dilated choroidal vessels. Fundus autofluorescence (FAF) showed a decreasing pattern of autofluorescence in the subretinal fluid area, and increasing autofluorescence at the border of the serous retinal detachment. Both patients were diagnosed with chronic central serous chorioretinopathy. Photodynamic therapy and intravitreal bevacizumab injection were administered for engorged choroidal vessels during follow-up, but neither patient showed improvement in symptoms or ophthalmologic findings. Based on re-evaluation by fundus photography, optical coherence tomography, fluorescein angiography, and comparison of the results of FAF with the first visit, vitelliform macular dystrophy was suspected and a definite diagnosis was made by electrooculography and genetic testing. CONCLUSION: In patients with continuous serous retinal detachment without response to photodynamic therapy or intravitreal bevacizumab injection, careful fundus exam and FAF can be used to diagnose atypical vitelliform macular dystrophy.

Improved performance of stretchable piezoelectric energy harvester based on stress rearrangement.

With the development of wearable devices and soft electronics, the demand for stretchable piezoelectric energy harvesters (SPEHs) has increased. Energy harvesting can provide energy when large batteries or power sources cannot be employed, and stretchability provides a user-friendly experience. However, the performance of SPEHs remains low, which limits their application. In this study, a wearable SPEH is developed by adopting a kirigami structure on a polyvinylidene fluoride film. The performance of the SPEH is improved by rearranging the stress distribution throughout the film. This is conducted using two approaches: topological depolarization, which eliminates the opposite charge generation by thermal treatment, and optimization of the neutral axis, which maximizes the stress applied at the surface of the piezoelectric film. The SPEH performance is experimentally measured and compared with that of existing SPEHs. Using these two approaches, the stress was rearranged in both the x-y plane and z-direction, and the output voltage increased by 21.57% compared with that of the original film with the same stretching motion. The generated energy harvester was successfully applied to smart transmittance-changing contact lenses.

The impact of the abnormal salinity enrichment in pore water on the thermodynamic stability of marine natural gas hydrates in the Arctic region.

In this study, the thermodynamic and structural characteristics of natural gas hydrates (NGHs) retrieved from gas hydrate mounds (ARAON Mound 03 (AM03) and ARAON Mound 06 (AM06)) in the Chukchi Sea in the Arctic region were investigated. The gas compositions, crystalline structure, and cage occupancy of the NGHs at AM03 and AM06 were experimentally measured using gas chromatography (GC), 13C nuclear magnetic resonance (NMR), Raman spectroscopy, and powder X-ray diffraction (PXRD). In the NGHs from AM03 and AM06, a significantly large fraction of CH4 (> 99%) and a very small amount of H2S were enclathrated in small (512) and large (51262) cages of sI hydrate. The NGHs from AM03 and AM06 were almost identical in composition, guest distributions, and existing environment to each other. The salinity of the residual pore water in the hydrate-bearing sediment (AM06) was measured to be 50.32‰, which was much higher than that of seawater (34.88‰). This abnormal salinity enrichment in the pore water of the low-permeability sediment might induce the dissociation of NGHs at a lower temperature than expected. The saturation changes in the NGHs that corresponded with an increase in the seawater temperature were also predicted on the basis of the salinity changes in the pore water. The experimental and predicted results of this study would be helpful for understanding the thermodynamic stability of NGHs and potential CH4-releasing phenomena in the Arctic region.

Evaluation of a lateral flow assay-based IFN-γ release assay as a point-of-care test for the diagnosis of latent tuberculosis infection.

INTRODUCTION: We compared the performance of a fluorescence lateral flow assay (ichroma™ IGRA-TB) with the QuantiFERON-TB Gold PLUS (QFT-PLUS) for the diagnosis of latent tuberculosis infection (LTBI) in patients with immune-mediated inflammatory diseases (IMID) prior to receiving biologics therapy. METHOD: The comparability of the ichroma™ IGRA-TB assay with the QFT-PLUS assay for the diagnosis of LTBI was determined in prospectively enrolled patients with IMID prior to receiving biologics between August 2018 and October 2019. To determine the best cut-off value of the ichroma™ IGRA-TB, an ROC curve analysis was performed. RESULTS: Patients with IMID (n = 145) had inflammatory bowel disease (n = 83; 57.2%), rheumatoid arthritis (n = 44; 30.3%), or spondyloarthropathy (n = 18; 12.4%). The median age was 40.5 (interquartile range: 27.0-56.0), 72 (49.7%) were men, and 140 (96.6%) received BCG vaccination. With the manufacturer-recommended cut-off values, 11 (7.6%) and 20 (13.8%) patients showed positive results with the ichroma™ IGRA-TB and QFT-PLUS tests, respectively. The overall agreement between the two tests was 91.0% with a Cohen's kappa value of 0.535 (95% confidence interval: 0.317-0.754). ROC curve analysis of the QFT-PLUS results showed that a cut-off value of > 0.21 IU/mL would improve the performance of the ichroma™ IGRA-TB. Using the new cut-off value, the concordance rate was improved to 93.1% with a Cohen's kappa value of 0.668 (95% confidence interval: 0.478-0.858). CONCLUSIONS: The ichroma™ IGRA-TB could be used as a point-of-care test for LTBI screening in IMID patients before starting biologics, especially in resource-limited settings. Key Points • The ichroma™ IGRA-TB is an automated fluorescence lateral flow assay-based IGRA. • The test has advantages like short turn-around time, low-cost, and ease of use. • The ichroma™ IGRA-TB showed high agreement with the QuantiFERON-TB Gold In-Tube in patients with chronic immune-mediated inflammatory diseases before starting biologics.

A Case of Livedoid Vasculopathy Successfully Treated with Sulodexide.

We report a 29-year-old female with a one-month history of non-healing multiple erythematous to violaceous plaques with crusts over both legs and feet. Tender, scarring ulcers with surrounding erythema were present. The clinical manifestation, together with histopathologic findings of fibrinoid plugs within vascular lumens and walls, as well as red blood cell extravasation, led to diagnosis of livedoid vasculopathy. The patient experienced recurrent painful violaceous plaques with ulcerations during the two years of treatment with oral pentoxifylline 400 mg three times daily. The cutaneous lesions and symptoms dramatically improved after the treatment regimen changed to oral sulodexide (250 lipasemic units) three times daily. Sulodexide, a highly purified mixture of glycosaminoglycans including dermatan sulfate and low-molecular weight heparin, could be an effective therapy for recalcitrant livedoid vasculopathy. Herein, we report a case of livedoid vasculopathy treated with sulodexide, which has not previously been reported.

Stretchable Biaxial and Shear Strain Sensors Using Diffractive Structural Colors.

Structural colors that can be changed dynamically, using either plasmonic nanostructures or photonic crystals, are rapidly emerging research areas for stretchable sensors. Despite the wide applications of various techniques to achieve strain-responsive structural colors, important factors in the feasibility of strain sensors-such as their sensing mechanism, stability, and reproducibility-have not yet been explored. Here, we introduce a stretchable, diffractive, color-based wireless strain sensor that can measure strain using the entire visible spectrum, based on an array of cone-shaped nanostructures on the surface of an elastomeric substrate. By stretching or compressing the substrate, the diffractive color can be tuned according to the changing grating pitch. Using the proposed method, we designed three types of strain-sensing modes: large-deformation (maximum 100%) tensile strain, biaxial 2D strain, and shear strain (maximum 78%). The strain sensors were fabricated, and applicability to strain-sensing was evaluated.

The dependence of the electrochemical properties of perfluorosulfonic acid membrane/water systems on repeat unit structure.

We developed a molecular thermodynamic framework to describe the dependence of the electrochemical properties of a perfluorosulfonic acid (PFSA) membrane/water system on the polymer structure. To better understand the behavior of the polymer membrane/water system, we developed a lattice model based on lattice cluster theory. We performed hypothetical calculations for a variety of repeat unit structures. We also investigated the correlation between the interaction energy and extending or reducing the chain length of the polymer repeat unit using COMPASS force fields. Our results indicate that the ionic conductivity of the nonpolar CF(2)CF(2) group in the main chain varies with the length of the chain. In addition, the ionic conductivity of different CF(2)CF(2) group chain lengths fluctuates according to hydration level. When OCF(2)CF(3)CF groups are substituted at 0 and 1, the predictions of the PFSA membrane agreed well with the experimental data from a Dow membrane. To obtain good ionic conductivity at a high vapor equilibrated hydration level, the nonpolar group in the polymer repeat unit and the substituted group chain connecting the nonpolar group length should both be short, and the substituted group chain connected with the sulfonic group should be long.

Soybean saponin inhibits tumor cell metastasis by modulating expressions of MMP-2, MMP-9 and TIMP- 2.

The antimetastatic properties of soybean saponin were investigated by evaluating matrix metalloproteinase (MMP-2 and MMP-9) production in HT-1080 cells. The mRNA expression levels of MMP-2 and MMP-9 were determined by RT-PCR analysis. The levels of secreted MMP-2, MMP-9 and tissue inhibitor of metalloproteinase-2 (TIMP-2) were determined by gelatin zymography and/or ELISA. The invasion of a Matrigel-coated membrane by human fibrosarcoma HT-1080 and HT-29 colon cancer cells was quantitatively assessed by counting the migrated cells. The treatment of HT-1080 cells with soybean saponin inhibited the mRNA expression of and reduced the amounts of secreted MMP-2 and MMP-9, whereas it increased the amount of secreted TIMP-2 dose-dependently. Soybean saponin significantly inhibited the invasion of HT-1080 cells through a Matrigel-coated membrane. The antimetastatic properties by soybean saponin were further confirmed by in vivo mice experiment via the tail vein injection of CT-26 colon cancer cells after feeding the mice the dietary soybean saponin. The incidence of metastatic tumor colonization of lungs of mice moderately decreased 2 weeks after the tail vein injection of CT-26 cells. Our current data support the notion that soybean saponin inhibits tumor cell metastasis by suppressing MMP-2 and MMP-9 productions, and stimulating TIMP-2 secretion, thereby suggesting that soybean saponin has a chemopreventive property against cancer metastasis.

Effect of itopride hydrochloride on the ileal and colonic motility in guinea pig in vitro.

PURPOSE: Itopride hydrochloride (itopride) inhibits acetylcholinesterase (AChE) and antagonizes dopamine D(2) receptor, and has been used as a gastroprokinetic agent. However, its prokinetic effect on the small bowel or colon has not yet been thoroughly investigated. The aim of this study was to investigate the effects of itopride on motor functions of the ileum and colon in guinea pigs. MATERIALS AND METHODS: The distal ileum was excised and the activity of peristaltic contraction was determined by measuring the amplitude and propagation velocity of peristaltic contraction. The distal colon was removed and connected to the chamber containing Krebs-Henseleit solution (K-H solution). Artificial fecal matter was inserted into the oral side of the lumen, and moved toward the anal side by intraluminal perfusion via peristaltic pump. Colonic transit times were measured by the time required for the artificial feces to move a total length of 10 cm with 2-cm intervals. RESULTS: In the ileum, itopride accelerated peristaltic velocity at higher dosage (10(-10)-10(-6) M) whereas neostigmine accelerated it only with a lower dosage (10(-10)-10(-9) M). Dopamine (10(-8) M) decelerated the velocity that was recovered by itopride infusion. Itopride and neostigmine significantly shortened colonic transit at a higher dosage (10(-10)-10(-6) M). Dopamine (10(-8) M) delayed colonic transit time that was also recovered after infusion of itopride. CONCLUSION: Itopride has prokinetic effects on both the ileum and colon, which are regulated through inhibitory effects on AChE and antagonistic effects on dopamine D(2) receptor.

[The effects of probiotics on symptoms of irritable bowel syndrome].

BACKGROUND/AIMS: Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) tract disorder that has heterogeneous clinical presentations such as abdominal pain, diarrhea, constipation, and abdominal distension. It is known that several mechanisms are involved in the pathogenesis of IBS. Probiotics may target one or more pathophysiologic pathways in IBS and may improve the symptoms of IBS. However, the results of studies about probiotics on IBS are controversial. Therefore, the aim of this study was to evaluate the effect of probiotics on GI symptoms and intestinal gas volume changes in patients with IBS. METHODS: Forty patients were randomly allocated to be treated with Medilac DS (Bacillus subtilis, Streptococcus faecium) (n=20) or placebo (n=20) in a double-blind, prospective manner. The change in intestinal gas volume and symptom scores after 4-week treatment were evaluated for the efficacy. RESULTS: There was no significant difference in bloating, frequency of gas expulsion, frequency of defecation, and hardness of stool before and after the treatment. However, the severity of abdominal pain and the frequency of abdominal pain decreased significantly in Medilac DS group (2.4+/-1.3 cm/day --> 1.6+/-1.6 cm/day, 1.7+/-1.3/day --> 1.0+/-1.0/day) (p=0.044, p=0.038), but not in placebo group (2.1+/-2.0 cm/day --> 1.8+/-2.1 cm/day, 1.3+/-1.2/day --> 1.4+/-1.9/day). In both groups, intestinal gas volume at baseline, after 2-week treatment, and after 4-week treatment did not show significant change. Medilac DS was well tolerated without adverse events. CONCLUSIONS: Medilac DS is a safe and useful probiotic agent for the treatment of abdominal pain in patients with IBS.