Evaluation of the mechanical properties of current biliary self-expandable metallic stents: axial and radial force, and axial force zero border

Background/Aims@#Mechanical properties (MPs) and axial and radial force (AF and RF) may influence the efficacy and complications of self-expandable metallic stent (SEMS) placement. We measured the MPs of various SEMSs and examined their influence on the SEMS clinical ability. @*Methods@#We evaluated the MPs of 29 types of 10-mm SEMSs. RF was measured using a conventional measurement device. AF was measured using the conventional and new methods, and the correlation between the methods was evaluated. @*Results@#A high correlation in AFs was observed, as measured by the new and conventional manual methods. AF and RF scatterplots divided the SEMSs into three subgroups according to structure: hook-and-cross-type (low AF and RF), cross-type (high AF and low RF), and laser-cut-type (intermediate AF and high RF). The hook-and-cross-type had the largest axial force zero border (>20°), followed by the laser-cut and cross types. @*Conclusions@#MPs were related to stent structure. Hook-and-cross-type SEMSs had a low AF and high axial force zero border and were considered safest because they caused minimal stress on the biliary wall. However, the increase in RF must be overcome.

Comparison of tube-assisted mapping biopsy with digital single-operator peroral cholangioscopy for preoperative evaluation of biliary tract cancer

Background/Aims@#Digital single-operator cholangioscopy (DSOC)-guided mapping biopsy (DMB) and tube-assisted mapping biopsy (TMB) are two techniques used for preoperative evaluation of biliary tract cancer (BTC). However, data regarding the diagnostic performance of these techniques are limited. @*Methods@#We retrospectively examined consecutive patients with BTC who underwent either technique at our institution between 2018 and 2020. We evaluated the technical success rate, adequate tissue acquisition rate, and diagnostic performance of these techniques for the evaluation of lateral spread of BTC. @*Results@#A total of 54 patients were included in the study. The technical success rate of reaching the target sites was 95% for DMB and 100% for TMB. The adequate tissue acquisition rate was 61% for DMB and 69% for TMB. The adequate tissue acquisition rate was low, especially for target sites beyond the secondary biliary radicles. The sensitivity of DMB alone was 39%, which improved to 65% when combined with visual impression. Experts demonstrated a higher negative predictive value and diagnostic accuracy with respect to both DSOC visual impression and DMB for the evaluation of lateral spread of BTC compared to trainees. @*Conclusions@#Adequate tissue acquisition rates were similar between the two techniques. Since DMB requires expertise, TMB may be an acceptable option when DSOC is unavailable or when DSOC expertise is limited.

Comparison of Endoscopic Ultrasound-Guided Tissue Acquisition Using a 20-Gauge Menghini Needle with a Lateral Forward Bevel and a 22-Gauge Franseen Needle: A Single-Center Large Cohort Study

Background/Aims@#Several fine-needle biopsy (FNB) needles are available for endoscopic ultrasound (EUS)-guided tissue acquisition. However, there is disagreement on which type of needle has the best diagnostic yield. The aim of this study was to compare the performance and safety of two commonly used EUS-FNB needles. @*Methods@#We retrospectively analyzed consecutive patients who underwent EUS-FNB between June 2016 and March 2020 in our hospital. Two types of needles were evaluated: a 20-gauge Menghini needle with a lateral forward bevel and a 22-gauge Franseen needle. Rapid on-site evaluation was performed in all the cases. A multivariate analysis was performed to clarify the negative predictive factors for obtaining a histological diagnosis. Propensity score matching was performed to compare the diagnostic yields of these two needles. @*Results@#We analyzed 666 patients and 690 lesions. The overall diagnostic rate of histology alone was 88.8%, and the overall adverse event rate was 1.5%. Transduodenal access and small lesions (≤2 cm) were identified as negative predictive factors for obtaining a histological diagnosis. After propensity score matching, 482 lesions were analyzed. The diagnostic accuracy rates of histology in the M and F needle groups were 89.2% and 88.8%, respectively (p=1.00). @*Conclusions@#Both the needles showed high diagnostic yield, and no significant difference in performance was observed between the two.

Comparison of Endoscopic Ultrasound-Guided Tissue Acquisition Using a 20-Gauge Menghini Needle with a Lateral Forward Bevel and a 22-Gauge Franseen Needle: A Single-Center Large Cohort Study

Background/Aims@#Several fine-needle biopsy (FNB) needles are available for endoscopic ultrasound (EUS)-guided tissue acquisition. However, there is disagreement on which type of needle has the best diagnostic yield. The aim of this study was to compare the performance and safety of two commonly used EUS-FNB needles. @*Methods@#We retrospectively analyzed consecutive patients who underwent EUS-FNB between June 2016 and March 2020 in our hospital. Two types of needles were evaluated: a 20-gauge Menghini needle with a lateral forward bevel and a 22-gauge Franseen needle. Rapid on-site evaluation was performed in all the cases. A multivariate analysis was performed to clarify the negative predictive factors for obtaining a histological diagnosis. Propensity score matching was performed to compare the diagnostic yields of these two needles. @*Results@#We analyzed 666 patients and 690 lesions. The overall diagnostic rate of histology alone was 88.8%, and the overall adverse event rate was 1.5%. Transduodenal access and small lesions (≤2 cm) were identified as negative predictive factors for obtaining a histological diagnosis. After propensity score matching, 482 lesions were analyzed. The diagnostic accuracy rates of histology in the M and F needle groups were 89.2% and 88.8%, respectively (p=1.00). @*Conclusions@#Both the needles showed high diagnostic yield, and no significant difference in performance was observed between the two.

Total Cholesterol Level for Assessing Pancreatic Insufficiency Due to Chronic Pancreatitis

BACKGROUND/AIMS: To determine the nutritional markers important for assessing the degree of pancreatic insufficiency due to chronic pancreatitis in routine clinical practice. METHODS: A total of 137 patients with chronic pancreatitis were followed up for more than 1 year. They were divided into two groups: a pancreatic diabetes mellitus (DM) group, consisting of 47 patients undergoing medical treatment for DM of pancreatic origin, and a nonpancreatic DM group, consisting of 90 other patients (including 86 patients without DM). Serum albumin, prealbumin, total cholesterol, cholinesterase, magnesium, and hemoglobin were compared between the two groups. RESULTS: The total cholesterol was significantly lower in the pancreatic than the nonpancreatic DM group (164 mg/dL vs 183 mg/dL, respectively; p=0.0028). Cholinesterase was significantly lower in the former group (263 U/L vs 291 U/L, respectively; p=0.016). Among the 37 patients with nonalcoholic pancreatitis, there was no difference in the cholinesterase levels between the pancreatic and nonpancreatic (296 U/L vs 304 U/L, respectively; p=0.752) DM groups, although cholesterol levels remained lower in the former (165 mg/dL vs 187 mg/dL, respectively; p=0.052). CONCLUSIONS: Cholinesterase levels are possibly affected by concomitant alcoholic liver injury. The total cholesterol level should be considered when assessing pancreatic insufficiency due to chronic pancreatitis.

A Novel, Fully Covered Laser-Cut Nitinol Stent with Antimigration Properties for Nonresectable Distal Malignant Biliary Obstruction: A Multicenter Feasibility Study

BACKGROUND/AIMS: Stent migration occurs frequently, but the prevention of complications resulting from covered self-expandable metal stents (C-SEMSs) remains unresolved. We prospectively assessed a newly developed C-SEMS, a modified covered Zeo stent (m-CZS), in terms of its antimigration effect. METHODS: Between February 2010 and January 2011, an m-CZS was inserted into 42 patients (31 initial drainage cases and 11 reintervention cases) at a tertiary referral center and three affiliated hospitals. The laser-cut stent was flared for 1.5 cm at both ends, with a 1 cm raised bank located 1 cm in from each flared end. The main outcome of this study was the rate of stent migration, and secondary outcomes were the rate of recurrent biliary obstruction (RBO), the time to RBO, the frequencies of complications, and overall survival. RESULTS: Of the 31 patients with initial drainage, stent migration occurred in four (12.9%, 95% confidence interval, 5.1% to 29.0%), with a mean time of 131 days. RBO occurred in 18 (58%), with a median time to RBO of 107 days. Following previous C-SEMS migration, seven of 10 patients (70%) did not experience m-CZS migration until death. CONCLUSIONS: m-CZSs with antimigration properties effectively, although not completely, prevented stent migration after stent insertion.

Genomic Basis for Methicillin Resistance in Staphylococcus aureus

Since the discovery of the first strain in 1961 in England, MRSA, the most notorious multidrug-resistant hospital pathogen, has spread all over the world. MRSA repeatedly turned down the challenges by number of chemotherapeutics, the fruits of modern organic chemistry. Now, we are in short of effective therapeutic agents against MRSA prevailing among immuno-compromised patients in the hospital. On top of this, we recently became aware of the rise of diverse clones of MRSA, some of which have increased pathogenic potential compared to the classical hospital-associated MRSA, and the others from veterinary sources. They increased rapidly in the community, and started menacing otherwise healthy individuals by causing unexpected acute infection. This review is intended to provide a whole picture of MRSA based on its genetic makeup as a versatile pathogen and our tenacious colonizer.

Current status of chemotherapy for the treatment of advanced biliary tract cancer

Chemotherapy is indispensable for the treatment of advanced biliary tract cancer. Recently, reports regarding first-line chemotherapy have increased, and first-line chemotherapy treatment has become gradually more sophisticated. Gemcitabine and cisplatin combination therapy (or gemcitabine and oxaliplatin combination therapy) have become the standard of care for advanced biliary tract cancer. Oral fluoropyrimidines have also been shown to have good antitumor effects. Gemcitabine, platinum compounds, and oral fluoropyrimidines are now considered key drugs for the treatment of advanced biliary tract cancer. Several clinical trials using molecular targeted agents are also ongoing. Combination therapy using cytotoxic agents and molecular-targeted agents has been evaluated widely. However, reports regarding second-line chemotherapy remain limited, and it has not yet been clarified whether second-line chemotherapy can improve the prognosis of advanced biliary tract cancer. Thus, there is an urgent need to establish second-line standard chemotherapy treatment for advanced biliary tract cancer. Several problems exist when assessing the results of previous reports concerning advanced biliary tract cancer. In the present review, the current status of the treatment of advanced biliary tract cancer is summarized, and several associated problems are indicated. These problems should be solved to achieve more sophisticated treatment of advanced biliary tract cancer.

Simultaneous Duodenal Metal Stent Placement and EUS-Guided Choledochoduodenostomy for Unresectable Pancreatic Cancer

Patients with pancreatic cancer frequently suffer from both biliary and duodenal obstruction. For such patients, both biliary and duodenal self-expandable metal stent placement is necessary to palliate their symptoms, but it was difficult to cross two metal stents. Recently, endoscopic ultrasonography-guided choledochoduodenostomy (EUS-CDS) was reported to be effective for patients with an inaccessible papilla. We report two cases of pancreatic cancer with both biliary and duodenal obstructions treated successfully with simultaneous duodenal metal stent placement and EUS-CDS. The first case was a 74-year-old man with pancreatic cancer. Duodenoscopy revealed that papilla had been invaded with tumor and duodenography showed severe stenosis in the horizontal portion. After a duodenal uncovered metal stent was placed across the duodenal stricture, EUS-CDS was performed. The second case was a 63-year-old man who previously had a covered metal stent placed for malignant biliary obstruction. After removing the previously placed metal stent, EUS-CDS was performed. Then, a duodenal covered metal stent was placed across the duodenal stenosis. Both patients could tolerate a regular diet and did not suffer from stent occlusion. EUS-CDS combined with duodenal metal stent placement may be an ideal treatment strategy in patients with pancreatic cancer with both duodenal and biliary malignant obstruction.

THERMOREGULATORY RESPONSES OF THE INITIAL STAGE OF BICYCLING IN A HEAT ENVIRONMENT / 体力科学

The purpose of this study is to determine the progress of whole body sweating rate (SR) in the initial stage of moderate work in two hot environments, and to relate the SR to the body temperature attained.<BR>Four healthy males, 28 to 31 years of age, performed leg exercise of 40% VO<SUB>2</SUB>max with a Monark bicycle ergometer set up on a platform scale (Potter bed balance) . All the experiments were carried out in a climatic chamber at ambient temperature (<I>T</I>a) of 30°C or 40°C (relative humidity, 45%) in winter season following body heating for 30 min at a room temperature of 30°C. Skin sweating was monitored by the bed balance with automatic weight change indicator throughout the experimental period. Rectal (<I>T</I>re) and 7 skin temperatures were measured every minute by a thermistor and thermocouples, respectively. Oxygen consumption was determined before and during the work by the Douglas bag method. Heart rate was recorded by electrocardiography throughout the experiment.<BR>At <I>T</I>a 40°C, the SR increased as soon as the work started, whereas at <I>T</I>a 30°C it took a few minutes. The mean SR during the work at <I>T</I>a 40°C was significantly higher than that at <I>T</I>a 30°C. The level of mean skin temperature (<I>T</I>sk) was higher at <I>T</I>a 40°C (35°C) than <I>T</I>a 30°C (33°C), and <I>T</I>re was approximately 37.3°C at <I>T</I>a 30°C and 40°C. The changes in the <I>T</I>re and <I>T</I>sk were similar in two different conditions. The negative correlations were found between the SR and the <I>T</I>sk during the work. The regression line was significantly different at <I>T</I>a 30°C and 40°C. The <I>T</I>sk decreased in proportion to increase of the SR. Moreover, there was a good correlation between the SR and heart rate during the work in both environments. Heat production stood at the same level in two different thermal conditions.<BR>The present study suggests that the body core temperature in working men is maintained at least constant level, since the evaporation in the initial stage of the work is largely stimulated, and the reduction of skin temperature may be caused by other factors than the evaporation.