73 research outputs found
"Communication and Coordination in Organizations" (in Japanese)
This paper analyzes a model of coordination where two agents attempt to coordinate their actions through communication. One agent (Sender) is engaged in finding the true state of nature in a stochastic environment and the action that best fits the state. The other agent (Receiver) in turn tries to ``understand'' the Sender's message and chooses his own action. Since the communication succeeds only probilistically, so does the coordination. In our model, two different modes of coordination are identified: the integral-type coordination based on the communication of soft information and the default-type coordination based on the predetermined default value. We find that the agents might choose the latter mode of coordination when the cost arising from the failed communication is high relative to the benefit from coordinating on the state-contingent best actions. Applications to the economics of organization are also discussed.
A case of pancreatic acinar cell carcinoma metastatic to skin
We report a rare case of pancreatic acinar cell carcinoma with widespread metastases in a 68-year-old woman who presented with subcutaneous nodules as the initial symptom. Computed tomography showed a pancreatic mass with hepatic tumors and enlarged lymph nodes besides ring-enhanced subcutaneous nodules. Magnetic resonance diffusionweighted imaging detected the presence of lesions in other organs. Histological analysis of a colonic polypoid lesion revealed carcinoma with endocrine and acinar differentiation compatible with pancreatic origin. Regrettably, she died of a cerebral infarction without any treatment, and autopsy findings confirmed our diagnosis
INTRODUCTION Clinical trials leading to drug approval (registra- tion trials) play a central role in the drug devel- opment process, and clinical trials in the general View and present status of personnel involved in clinical trials : a survey of particip
. Among the support staff, 36 (80% %) had more than 5 years of experience. The most common questionnaire answer selected for participation in the symposium was "willing to contact staff from other medical institutions or organizations" for support staff and "to obtain further knowledge concerning clinical trials" for medical staff. The overall view of the discussion ("Was the discussion satisfactory?") was favorable for 36 (53% %) respondents. This survey revealed that the group discussion in the present symposium appears to be valuable for participants, using overall satisfaction as a surrogate. Based on the information obtained in the present study, further development of the clinical trial infrastructure, including training opportunities and career development for support staff, is required. Due to the limitations of this study, further analysis is warranted to determine the optimal strategy for training support staff. J. Med. Invest. 58 : 81-85, February, 201
Muscle-specific tyrosine kinase-antibody-positive myasthenic crisis with detailed electrophysiologic studies.
A 69-year-old male who presented in a coma due to sudden respiratory arrest was transferred to our hospital. After endotracheal intubation with manual ventilation, he became alert and his neurologic findings were within the normal range, except for palsy of the respiratory muscles. Biochemical analyses of the blood and brain computed tomography failed to indicate the cause of the respiratory arrest. An edrophonium test did not improve the respiratory arrest. An urgent electromyogram at the dorsal interossei, biceps, and sternocleidomastoideus muscle and a repetitive nerve stimulation test at the trapezius and deltoid muscle were also negative on the first hospital day. However, on the 16th day in the hospital, a repetitive nerve stimulation test at the levator labii superioris alaeque nasi showed a waning phenomenon. This result indicated a diagnosis of myasthenia gravis. Anti.muscle-specific tyrosine kinase antibody was found to be positive. After treatment with plasmapheresis and prednisolone, he regained normal respiratory function. Anti.muscle-specific tyrosine kinase (MuSK)-antibodypositive myasthenia gravis (MG) (MuSK-MG) tends to be associated with a lower incidence of a positive edrophonium test, a lower incidence of a positive electrophysiologic study excluding the face, and a higher incidence of respiratory failure in comparison to anti.acetylcholine receptors (AchR)-antibody-positive MG (AchR-MG). Respiratory failure is curable with treatment. Accordingly, in addition to obtaining a precise diagnosis, an emergency physician should recommend an electrophysiologic study including the face to make a differential diagnosis for respiratory arrest when biochemical and radiologic studies fail to indicate the cause of the respiratory arrest
Radiological prediction of tumor invasiveness of lung adenocarcinoma on thin-section CT
To evaluate thin-section computed tomography (CT) (TSCT) features that differentiate adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IVA), and to determine the size of solid portion on CT that correlates to pathological invasive components. Forty-eight patients were included. Nodules were classified into ground-glass nodule (GGN), part-solid, solid, and heterogeneous. Visual density of GGNs was subjectively evaluated using reference standard images: faint GGN (Ga), â400âHU; and mixed (Gaâ+âGb, Gaâ+âGc, and Gbâ+âGc). The evaluated TSCT findings included margin of nodule, distribution of solid portion, distribution of air bronchiologram, and pleural indentation. The longest diameters of the solid portion and the entire tumor were measured. Invasive diameters were measured in pathological specimens. Twenty-two AISs (16 GGNs [7 Ga, 5 Gb, 2 Gc, 1 Gaâ+âGc, 1 Gbâ+âGc], 4 part-solids, and 2 heterogeneous), 6 MIAs (1 GGN [Gbâ+âGc], 3 part-solids, and 2 solids), and 20 IVAs (1 GGN [Gb], 3 part-solids, and 16 solid) were found. The longest diameter (meanâ±âstandard deviation) of the solid portion and total tumor were 9.7â±â9.7 and 18.9â±â5.6âmm, respectively. Significant differences in TSCT findings between AIS and IVA were margin of nodule (Pearson chi-squared test, Pâ=â0.004), distribution of air bronchiologram (Pâ=â0.0148), and pleural indentation (Pâ=â0.0067). A solid portion >5.3âmm on TSCT indicated MIA or IVA, and >7.3âmm indicated IVA (receiver operating characteristic analysis, Pâ7.3âmm on TSCT indicates IVA
View and present status of personnel involved in clinical trials : a survey of participants from the First Symposium of the Shikoku Collaborative Group for Promotion of Clinical Trials
Clinical trials leading to drug approval (registration trials) play a central role in the drug development process. Since the introduction of the Good Clinical Practice (GCP) standard in 1997, the Japanese infrastructure for registration trials has improved. The contribution of support staff, including clinical research coordinators (CRCs), to clinical trials is now widely recognized in Japan. Quality issues and career development for these support staff are being increasingly emphasized. The Shikoku Collaborative Group for Promotion of Clinical Trials was organized in 2008 to address these issues through communication with the personnel involved in clinical trials in regional areas of Japan. To understand the views and present status of personnel involved in clinical trials, we used questionnaires to survey the participants of the First Symposium of the Shikoku Collaborative Group for Promotion of Clinical Trials held in August 2009. Group discussions and special lectures occurred at the symposium. The questionnaire began with questions about basic patient characteristics, followed by practical questions. Of 110 participants, there were 68 respondents (62%), including clinical trial support staff (clinical research coordinators [n=36, 53%], administrative officers [n=9, 13%]), and medical staff [n=23, 34%]). Among the support staff, 36 (80%) had more than 5 years of experience. The most common questionnaire answer selected for participation in the symposium was âwilling to contact staff from other medical institutions or organizationsâ for support staff and âto obtain further knowledge concerning clinical trialsâ for medical staff. The overall view of the discussion (âWas the discussion satisfactory?â) was favorable for 36 (53%) respondents. This survey revealed that the group discussion in the present symposium appears to be valuable for participants, using overall satisfaction as a surrogate. Based on the information obtained in the present study, further development of the clinical trial infrastructure, including training opportunities and career development for support staff, is required. Due to the limitations of this study, further analysis is warranted to determine the optimal strategy for training support staff
Application of deep learning (3-dimensional convolutional neural network) for the prediction of pathological invasiveness in lung adenocarcinoma
To compare results for radiological prediction of pathological invasiveness in lung adenocarcinoma between radiologists and a deep learning (DL) system.Ninety patients (50 men, 40 women; mean age, 66 years; range, 40-88 years) who underwent pre-operative chest computed tomography (CT) with 0.625-mm slice thickness were included in this retrospective study. Twenty-four cases of adenocarcinoma in situ (AIS), 20 cases of minimally invasive adenocarcinoma (MIA), and 46 cases of invasive adenocarcinoma (IVA) were pathologically diagnosed. Three radiologists of different levels of experience diagnosed each nodule by using previously documented CT findings to predict pathological invasiveness. DL was structured using a 3-dimensional (3D) convolutional neural network (3D-CNN) constructed with 2 successive pairs of convolution and max-pooling layers, and 2 fully connected layers. The output layer comprises 3 nodes to recognize the 3 conditions of adenocarcinoma (AIS, MIA, and IVA) or 2 nodes for 2 conditions (AIS and MIA/IVA). Results from DL and the 3 radiologists were statistically compared.No significant differences in pathological diagnostic accuracy rates were seen between DL and the 3 radiologists (P>. 11). Receiver operating characteristic analysis demonstrated that area under the curve for DL (0.712) was almost the same as that for the radiologist with extensive experience (0.714; P=. 98). Compared with the consensus results from radiologists, DL offered significantly inferior sensitivity (P=. 0005), but significantly superior specificity (P=. 02).Despite the small training data set, diagnostic performance of DL was almost the same as the radiologist with extensive experience. In particular, DL provided higher specificity than radiologists
Development of a novel automatic ascites filtration and concentration equipment with multiâringâtype roller pump units for cellâfree and concentrated ascites reinfusion therapy
Cellâfree and concentrated ascites reinfusion therapy (CART) is an effective therapy for refractory ascites. However, CART is difficult to perform as ascites filtration and concentration is a complicated procedure. Moreover, the procedure requires the constant assistance of a clinical engineer or/and the use of an expensive equipment for the multiâpurpose blood processing. Therefore, we developed a CART specialized equipment (mobility CART [MâCART]) that could be used safely with various safety measures and automatic functions such as automatic washing of clogged filtration filter and selfâregulation of the concentration ratio. Downsizing, lightning of the weight, and automatic processing in MâCART required the use of newly developed multiâringâtype roller pump units. This equipment was approved under Japanese regulations in 2018. In performing 41 sessions of CART (for malignant ascites, 22 sessions; and hepatic ascites, 19 sessions) using this equipment in 17 patients, no serious adverse event occurred. An average of 4494 g of ascites was collected and the total amount of ascites was processed in all the sessions without any trouble. The mean weight of the processed ascites was 560 g and the mean concentration ratio was 8.0. The ascites were processed at a flow rate of 50 mL/min. The mean ascites processing time was 112.5 minutes and a 106.5âminutes (95.2%) ascites processing was performed automatically. The operator responded to alarms or support information 3.2 times on average (3.1 minutes, 2.1% of ascites processing time). Human errors related to ascites processing were detected by MâCART at 0.4 times per session on average and were appropriately addressed by the operator. The frequencies of automatic washing of clogged filtration filter and selfâregulation of the concentration ratio were 31.7% and 53.7%, respectively. The mean recovery rates (recovery dose) of protein, albumin, and immunoglobulin G were 72.9%, 72.9%, and 71.2% (65.9 g, 34.9 g, and 13.2 g), respectively. Steroids were administered in 92.7% of the sessions to prevent fever and the mean increase in body temperature was 0.53°C. MâCART is a compact and lightweight automatic CART specialized equipment that can safely and easily process a large quantity of ascites without the constant assistance of an operator
Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner
Purpose: The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods: This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm à 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm à 16 or 0.5 mm à 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. Results: The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P <.0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P <.0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary ves sels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Conclusion: Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners
- âŠ