Pore-scale modeling of two-phase flow: A comparison of the generalized network model to direct numerical simulation

Despite recent advances in pore-scale modeling of two-phase flow through porous media, the relative strengths and limitations of various modeling approaches have been largely unexplored. In this work, two-phase flow simulations from the generalized network model (GNM) [Phys. Rev. E 96, 013312 (2017)2470-004510.1103/PhysRevE.96.013312; Phys. Rev. E 97, 023308 (2018)2470-004510.1103/PhysRevE.97.023308] are compared with a recently developed lattice-Boltzmann model (LBM) [Adv. Water Resour. 116, 56 (2018)0309-170810.1016/j.advwatres.2018.03.014; J. Colloid Interface Sci. 576, 486 (2020)0021-979710.1016/j.jcis.2020.03.074] for drainage and waterflooding in two samples-a synthetic beadpack and a micro-CT imaged Bentheimer sandstone-under water-wet, mixed-wet, and oil-wet conditions. Macroscopic capillary pressure analysis reveals good agreement between the two models, and with experiments, at intermediate saturations but shows large discrepancy at the end-points. At a resolution of 10 grid blocks per average throat, the LBM is unable to capture the effect of layer flow which manifests as abnormally large initial water and residual oil saturations. Critically, pore-by-pore analysis shows that the absence of layer flow limits displacement to invasion-percolation in mixed-wet systems. The GNM is able to capture the effect of layers, and exhibits predictions closer to experimental observations in water and mixed-wet Bentheimer sandstones. Overall, a workflow for the comparison of pore-network models with direct numerical simulation of multiphase flow is presented. The GNM is shown to be an attractive option for cost and time-effective predictions of two-phase flow, and the importance of small-scale flow features in the accurate representation of pore-scale physics is highlighted.

Using energy balance to determine pore-scale wettability

HYPOTHESIS

Based on energy balance during two-phase displacement in porous media, it has recently been shown that a thermodynamically consistent contact angle can be determined from micro-tomography images. However, the impact of viscous dissipation on the energy balance has not been fully understood. Furthermore, it is of great importance to determine the spatial distribution of wettability. We use direct numerical simulation to validate the determination of the thermodynamic contact angle both in an entire domain and on a pore-by-pore basis.

SIMULATIONS

Two-phase direct numerical simulations are performed on complex 3D porous media with three wettability states: uniformly water-wet, uniformly oil-wet, and non-uniform mixed-wet. Using the simulated fluid configurations, the thermodynamic contact angle is computed, then compared with the input contact angles.

FINDINGS

The impact of viscous dissipation on the energy balance is quantified; it is insignificant for water flooding in water-wet and mixed-wet media, resulting in an accurate estimation of a representative contact angle for the entire domain even if viscous effects are ignored. An increasing trend in the computed thermodynamic contact angle during water injection is shown to be a manifestation of the displacement sequence. Furthermore, the spatial distribution of wettability can be represented by the thermodynamic contact angle computed on a pore-by-pore basis.

Evaluation of methods using topology and integral geometry to assess wettability

HYPOTHESIS

The development of high-resolution in situ imaging has allowed contact angles to be measured directly inside porous materials. We evaluate the use of concepts in integral geometry to determine contact angle. Specifically, we test the hypothesis that it is possible to determine an average contact angle from measurements of the Gaussian curvature of the fluid/fluid meniscus using the Gauss-Bonnet theorem.

THEORY AND SIMULATION

We show that it is not possible to unambiguously determine an average contact angle from the Gauss-Bonnet theorem. We instead present an approximate relationship: 2πn(1-cosθ)=4π-∫κ_G12dS₁₂, where n is the number of closed loops of the three-phase contact line where phases 1 and 2 contact the surface, θ is the average contact angle, while κ_G12 is the Gaussian curvature of the fluid meniscus which is integrated over its surface S₁₂. We then use the results of pore-scale lattice Boltzmann simulations to assess the accuracy of this approach to determine a representative contact angle for two-phase flow in porous media.

FINDINGS

We show that in simple cases with a flat solid surface, the approximate expression works well. When applied to simulations on pore space images, the equation provides a robust estimate of contact angle, accurate to within 3°, when averaged over many fluid clusters, although individual values can have significant errors because of the approximations used in the calculation.

Pore-scale numerical simulation of low salinity water flooding using the lattice Boltzmann method

HYPOTHESIS

The change of wettability toward more water-wet by the injection of low salinity water can improve oil recovery from porous rocks, which is known as low salinity water flooding. To simulate this process at the pore-scale, we propose that the alteration in surface wettability mediated by thin water films which are below the resolution of simulation grid blocks has to be considered, as observed in experiments. This is modeled by a wettability alteration model based on rate-limited adsorption of ions onto the rock surface.

SIMULATIONS

The wettability alteration model is developed and incorporated into a lattice Boltzmann simulator which solves both the Navier-Stokes equation for oil/water two-phase flow and the advection-diffusion equation for ion transport. The model is validated against two experiments in the literature, then applied to 3D micro-CT images of a rock.

FINDINGS

Our model correctly simulated the experimental observations caused by the slow wettability alteration driven by the development of water films. In the simulations on the 3D rock pore structure, a distinct difference in the mixing of high and low salinity water is observed between secondary and tertiary low salinity flooding, resulting in different oil recoveries.

Quantification of Uncertainty and Best Practice in Computing Interfacial Curvature from Complex Pore Space Images

Recent advances in high-resolution three-dimensional X-ray CT imaging have made it possible to visualize fluid configurations during multiphase displacement at the pore-scale. However, there is an inherited difficulty in image-based curvature measurements: the use of voxelized image data may introduce significant error, which has not-to date-been quantified. To find the best method to compute curvature from micro-CT images and quantify the likely error, we performed drainage and imbibition direct numerical simulations for an oil/water system on a bead pack and a Bentheimer sandstone. From the simulations, local fluid configurations and fluid pressures were obtained. We then investigated methods to compute curvature on the oil/water interface. The interface was defined in two ways; in one case the simulated interface with a sub-resolution smoothness was used, while the other was a smoothed interface extracted from synthetic segmented data based on the simulated phase distribution. The curvature computed on these surfaces was compared with that obtained from the simulated capillary pressure, which does not depend on the explicit consideration of the shape of the interface. As distinguished from previous studies which compared an average or peak curvature with the value derived from the measured macroscopic capillary pressure, our approach can also be used to study the pore-by-pore variation. This paper suggests the best method to compute curvature on images with a quantification of likely errors: local capillary pressures for each pore can be estimated to within 30% if the average radius of curvature is more than 6 times the image resolution, while the average capillary pressure can also be estimated to within 11% if the average radius of curvature is more than 10 times the image resolution.

Treatment of an Arteriovenous Shunt Draining into a Venous Angioma by Selective Embolisation

We treated a 62-year-old woman who suffered from intraventricular haemorrhage. Angiography revealed an arteriovenous shunt draining into a venous angioma. She was successfully treated by obliteration of the arteriovenous shunt with transarterial embolisation.

Angiography performed after embolisation demonstrated that the persisting venous angioma served as the draning vein for normal middle cerebral artery perfusion.

We believe that selective arterial occlusion with preservation of the venous component is the best treatment for this type of mixed vascular malformation.

Coil Embolization for Intracranial Aneurysm by Direct Puncture of the Carotid Artery in Elderly Patients

Seven aneurysms in elderly patients (average 78 year-old) were treated by intra-aneurysmal coil embolization. The 19 gage elastic needle or 4.0Fr. sheath introducer was placed into the carotid artery, and 3.0Fr. microcatheter was advanced into the aneurysm.

An operative difficulty to approach to the aneurysm due to arteriosclerosis was ameliorated by this method. Mobility related to this procedure was a local hematoma at the puncture site in one case.

Assessment for diagnosis of lymph node metastasis in esophageal cancer using endoscopic ultrasound elastography

BACKGROUND

We performed endoscopic ultrasound real-time tissue elastography to more accurately diagnose lymph node metastasis of esophageal cancer. The aim of this study was to evaluate the ability of EUS elastography to distinguish benign from malignant lymph nodes in esophageal cancer patients.

METHODS

The present study had two steps. As the first step (study 1), we developed diagnostic criteria for metastatic lymph nodes using elastography and verified the validity of the criteria. Three hundred and twenty-two lymph nodes from 35 patients treated by surgical resection were included in the study. As the second step (study 2), we preoperatively examined the lymph nodes of esophageal cancer patients with EUS elastography and compared its diagnostic performance with that of the conventional B-mode EUS images. A total of 115 lymph nodes from 31 patients were included.

RESULTS

In study 1, lymph nodes were considered malignant if 50 % or more of the node appeared blue, or if the peripheral part of the lesion was blue and the central part was red/yellow/green. The sensitivity and specificity of the elastography were 79.7 and 97.6 % with an accuracy of 93.8 %, which was significantly higher than the values for conventional B-mode imaging. In study 2, the sensitivity and specificity of the EUS elastography were 91.2 and 94.5 % with an accuracy of 93.9 %, which was also significantly higher than the values for conventional B-mode EUS imaging.

CONCLUSIONS

The present study demonstrated that EUS elastography is useful for diagnosing lymph node metastasis of esophageal cancer.

Usefulness of the Bollinger scoring method in evaluating peripheral artery angiography with 64-low computed tomography in patients with peripheral arterial disease

AIM

There are various angiographic and runoff scoring systems for evaluating stenosis and arterial occlusion in patients with peripheral artery disease (PAD). The report from the BASIL trial revealed that the Bollinger scoring system, originally designed to classify intra-arterial digital subtraction angiography (IADSA), was sensitive to differences in PAD. The purpose of the present study was to evaluate the application of the Bollinger scoring system to a 64-low multidetector computed tomography (MDCT) in PAD patients.

METHODS

Patients with PAD who underwent both a 64-MDCT and DSA within a 4-year period were enrolled in the study. Two observers analyzed the MDCT and DSA images for each patient. We divided the arterial tree from the common iliac artery to the plantar arch into 16 segments and scored 0-15 points for each segment as reported by Bollinger, according to the severity and extent of disease. We analyzed the reliability of differences in scores between the DSA and MDCT by the intraclass correlation coefficients (ICCs).

RESULTS

We reviewed 100 consecutive patients (127 limbs) and assessed a total of 1929 segments. The Bollinger score of the 2 tests were same in 39.6% of all segments. The difference between the 2 tests were within 2 points in 77.3% of the above-knee segments (70.1-91.6% in each segments), 58.8% of the below-knee segments with the exception of plantar arch (42-74%). The ICC values showed relatively good reliability, but in the CFA the ICC values showed poor reliability.

CONCLUSION

The Bollinger scoring method is a useful tool to evaluate peripheral artery angiography with 64-low CT in patients with PAD.

Monitoring salivary amylase activity is useful for providing timely analgesia under sedation

AIM: To detect the criteria and cause of elevated salivary amylase activity (sAMY) in patients undergoing endoscopic submucosal dissection (ESD) under sedation.

METHODS: A total of 41 patients with early gastric cancer removed via ESD under deep sedation (DS) were enrolled. The perioperative sAMY, which was shown as sympathetic excitements (SE), was measured. The time at which a patient exhibited a relatively increased rate of sAMY compared with the preoperative baseline level (IR, %) ≥ 100% (twice the actual value) was assumed as the moment when the patient received SE. Among the 41 patients, we focused on 14 patients who exhibited an IR ≥ 100% at any time that was associated with sAMY elevation during ESD (H-group) and examined whether any particular endoscopic procedures can cause SE by simultaneously monitoring the sAMY level. If a patient demonstrated an elevated sAMY level above twice the baseline level, the endoscopic procedure was immediately stopped. In the impossible case of discontinuance, analgesic medicines were administered. This study was performed prospectively.

RESULTS: A total of 26 episodes of sAMY eruption were considered moments of SE in the H-group. The baseline level of sAMY significantly increased in association with an IR of > 100% at 5 min, with a significant difference (IR immediately before elevation/IR at elevation of sAMY = 8.72 ± 173/958 ± 1391%, P < 0.001). However, effective intervention decreased the elevated sAMY level immediately within only 5 min, with a significant difference (IR at sAMY elevation/immediately after intervention = 958 ± 1391/476 ± 1031, P < 0.001). The bispectral indices, systolic blood pressure and pulse rates, which were measured at the same time, remained stable throughout the ESD. Forceful endoscopic insertion or over insufflation was performed during 22 of the 26 episodes. Release of the gastric wall tension and/or the administration of analgesic medication resulted in the immediate recovery of the elevated sAMY level, independent of body movement.

CONCLUSION: By detecting twice the actual sAMY based on the preoperative level, the release of the gastric wall tension or the administration of analgesic agents should be considered.

[A case of advanced gastric cancer with para-aortic lymph node metastases responding to S-1/CDDP chemotherapy that leads to a pathological complete response]

A 66-year-old man complaining of epigastralgia was referred to our hospital. We examined the patient and diagnosed advanced gastric cancer (ML, type 3, por, cT3, cN3, cH0, cP0, cM1[LYM], cStage IV). A poor outcome was predicted, so we attempted induction chemotherapy and expected tumor downstaging. We chose S-1/CDDP therapy. S-1 was administered orally for 21 days, followed by CDDP div on day 8. Total gastrectomy and lymph node dissection (D2+No. 12a, No. 13,16) was performed using Roux-en-Y reconstruction. Histological examination of the resected stomach and lymph nodes revealed no residual cancer cells, suggesting complete histological remission (grade 3) according to the Japanese classification of gastric carcinoma. The patient has been in good health without recurrence for 12 months after surgery.

A flexible-arm liver retractor that provides an optimal surgical field without postoperative liver dysfunction

BACKGROUND/AIMS

It is important to retract the lateral liver segment during laparoscopic gastrectomy to achieve an optimal surgical field. Few retractors cause transient liver dysfunction after surgery; therefore, for an easier and safer procedure, we devised a new liver retractor and implemented a trial clinical application.

METHODOLOGY

The novel liver retractor comprises a metallic, flexible arm retractor attached to the operating table and an air compressor which pneumatically moves and fixes the retractor. It was inserted directly into the abdominal cavity just below the xiphisternum to retract the left lobe of the liver anterosuperiorly, thereby exposing the hiatus. Blood samples were collected from the patients on days 1, 3, and 7 after surgery to assess the levels of the liver enzymes AST and ALT.

RESULTS

During laparoscopic gastrectomy, no liver damage was observed macroscopically. The surgical fields obtained were optimal and efficient for laparoscopic surgery. Notably, it was possible to retract the liver as often as needed. Further, none of the patients developed postoperative liver dysfunction.

CONCLUSIONS

The novel flexible-arm retractor provided an optimal surgical field without inducing liver dysfunction.

Surgical advantages of gastric SMTs by laparoscopy and endoscopy cooperative surgery

BACKGROUND/AIMS

The treatment of gastric submucosal tumors (SMTs) is strictly surgical and enucleation of the tumor or wedge resection of the stomach is efficient to achieve R0 resection. Laparoscopic and endoscopic cooperative surgery (LECS) can be safely performed with adequate cutting lines. This study describes the initial 16 cases treated by LECS and evaluates the advantages by LECS for gastric SMTs retrospectively.

METHODOLOGY

Sixteen patients with gastric SMT underwent LECS from June 2007 to December 2010, their surgical data, clinical characteristics and surgical specimens of SMTs were compared. The surgical specimens of 9 gastric SMTs treated by laparoscopic wedge resection (LWR) were compared as a control.

RESULTS

The median (range) length of operation time, blood loss, hospital stay after surgery were minutes 172 (115- 220), <5mL (<5-115) and 10 days (6-17), respectively. The median (range) ratio of the longest diameter of the tumor divided by the longest diameter of the surgical specimen in LECS and LWR were 0.86 (0.625-1.0) and 0.69 (0.44-1.0), respectively (p=0.0189, Wilcoxon rank sum test).

CONCLUSIONS

LECS minimizes the surgical specimen while still providing sufficient surgical margins to successfully cure gastric SMTs.

Rapid diagnosis of micrometastasis of gastric cancer using reverse transcription loop-mediated isothermal amplification

Methods to detect metastases in biopsy specimens with certain rapidity and accuracy are essential to performing tailor-made surgeries for solid malignancies. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction is a novel technique for detecting mRNA expression of target sequences with high sensitivity and rapidity, even from crude samples without RNA purification. Applicability to detect lymph node (LN) micrometastasis of gastric cancer was tested. Total of 26 LNs were retrieved from 10 patients with primary gastric cancer. Each LN was serially sectioned, and every set of three serial sections were tested for routine histopathological (H&E) and immunohistochemical examination with anti-cytokeratin antibodies (IHC), and RT-LAMP analysis targeted cytokeratin 19 mRNA. Results from H&E/IHC and RT-LAMP analysis were compared in each set of sections. All the sections of those containing metastatic lesions equivalent to a volume of overt metastasis (maximum diameter>2 mm), 90% of those containing micrometastasis (between 2 and 0.2 mm) and 83% of those containing isolated tumor cells (<0.2 mm) were detectable using this procedure. Total analysis from lysates of clinical specimens required<75 min. This new technique is suggested to be an alternative to rapid diagnosis of micrometastasis based on conventional histopathological analysis.

Culture of bovine embryos in polyester mesh sections: the effect of pore size and oxygen tension on in vitro development

The purpose of this study was to assess the feasibility of polyester mesh culture for the in vitro production of bovine embryos, as polyester mesh is an alternative way for tracking individual embryos throughout culture using time-lapse cinematography (TLC). Bovine embryos were isolated during in vitro culture using sections of three different polyethylene terephthalate (PET) mesh products. In vitro matured and fertilized bovine oocytes were cultured in the 217 × 217, 230 × 230 or 238 × 238-μm openings of PET mesh sections or in simple micro-drops (control) for 7 days under either 20% or 5% O(2) tensions. No difference in embryo developmental rates was found between the culture groups in terms of cleavage, blastocyst formation and blastocyst expansion irrespective of O(2) tension. In contrast, under 20% O(2) tension, blastocysts that developed in PET mesh with 217 × 217-μm opening had significantly higher numbers of total and trophectoderm (TE) cells than control embryos; however, the numbers and proportions of inner cell mass (ICM) cells did not differ. Under 5% O(2) tension, no difference was found among the culture groups in the numbers of total, ICM and TE cells in embryos. All three PET mesh products investigated in this study were proven to be effective to prevent embryo movement. The results demonstrate that bovine embryos can be cultured in PET mesh sections without negative side-effects and suggest that embryo distance determined by the mesh affects embryo quality at atmospheric oxygen tension. Polyethylene terephthalate mesh with 217 × 217-μm openings was found to be the most suitable for further application in TLC.

Low peritoneal and systemic inflammatory response after laparoscopy-assisted gastrectomy compared to open gastrectomy

BACKGROUND/AIMS

Peritoneal immune response as well as systemic response was objectively evaluated in laparoscopy-assisted distal gastrectomy (LADG) compared to open distal gastrectomy (ODG).

METHODOLOGY

A total of 42 patients with gastric cancer were enrolled, with 23 undergoing LADG and 19 ODG. We evaluated the levels of IL-6 in peritoneal drain fluid, serum C-reactive protein (CRP), white blood cells (WBC), and the postoperative presence of systemic inflammatory response syndrome (SIRS).

RESULTS

The serum CRP level was significantly higher in the ODG group than in the LADG group (p=0.007) on postoperative day (POD) 1. WBC counts showed no statistically significant difference between the two groups (p=0.105). The rate of cases exhibiting SIRS was significantly higher in the ODG group than in the LADG group (p<0.001). The IL-6 level of drain fluid was significantly higher in the ODG group than the LADG group (p<0.01) on POD1. Although weak correlation between IL-6 on POD1 and blood loss (R=0.38, p=0.0154) was observed, no significant correlation between IL-6 and operation time was noted.

CONCLUSIONS

LADG seems to be a lesser traumatic approach for the treatment of gastric cancer.

138 TIME-LAPSE CINEMATOGRAPHY-COMPATIBLE INJECTION-MOLDED MICROWELL CULTURE SYSTEM FOR TRACKING THE DEVELOPMENT OF INDIVIDUAL BOVINE EMBRYOS

We have developed a polystyrene-based well of-the-well system (WOW) using injection moulding to track individual embryos throughout culture using time-lapse cinematography (TLC). The WOW-cultured bovine embryos following in vitro fertilization (IVF) were compared with conventional droplet (control)-cultured embryos on in vitro and in vivo development. Twenty-five of zygotes were cultured in each culture system containing 125 μL of CR1aa medium supplemented with 5% calf serum for 168 h after IVF. No differences between control- and WOW-cultured embryos were observed during development to the blastocyst stage. Morphological quality, inner cell mass (ICM), and trophectoderm (TE) cell numbers and post-vitrification survival rates were not different between control- and WOW-derived blastocysts; however, incidence of apoptosis in the ICM and TE cells was reduced in WOW culture (P < 0.01). Oxygen consumption in WOW-derived blastocysts was closer to physiological level than that of control-derived blastocysts. Moreover, WOW culture improved embryo viability, as indicated by increased pregnancy rates at days 30 and 60 after embryo transfer (P < 0.05). The TLC monitoring was performed to evaluate the cleavage pattern and the duration of the first cell cycle of embryos from oocytes collected by ovum pick-up; correlations with success of pregnancy were determined. Logistic regression analysis indicated that the cleavage pattern correlated with success of pregnancy (P < 0.05), but cell cycle length did not. Higher pregnancy rates (66.7%) were observed for animals in which transferred blastocysts had undergone normal cleavage, identified by the presence of 2 blastomeres of the same size without fragmentation, than among those with abnormal cleavage (33.3%). These results suggest that our microwell culture system is a powerful tool for producing and selecting healthy embryos and for identifying viability biomarkers. This work was supported by the Research and Developmental Program for New Bio-Industry Initiatives.

The classification of anatomic variations in the perigastric vessels by dual-phase CT to reduce intraoperative bleeding during laparoscopic gastrectomy

BACKGROUND

Laparoscopy-assisted distal gastrectomy (LADG) is a less invasive alternative compared with an open procedure. However, it is difficult to obtain a full-view image and to estimate the three-dimensional (3D) relationships between organs during laparoscopic procedures. Determining the vascular anatomy by 3D CT imaging has been shown to play a critical role in reducing the risks associated with laparoscopic gastric cancer surgery. The purpose of this study was to evaluate the clinical anatomic variations and to estimate its positive contribution in obtaining less intraoperative bleeding.

METHODS

Scanning was performed using a 64-row MDCT scanner. Three-dimensional CT images in the arterial and portal phase were reconstructed and fused together using the volume-rendering technique. The intraoperative bleeding findings were compared between two periods.

RESULTS

The anatomic variations of the celiac trunk were divided into six types. There were 159 patients with Adachi's type I, type II=8, type III=1, type IV=1, type V=2, type VI=3, and other=1. The inflows of the left gastric coronary vein (LCV) were divided into three types. The LCV flowed into the portal vein (PV) in 79 patients, into the splenic vein (SpV) in 65, and into the junction of these two veins in 27. The splenic artery was divided into flat type and curved type, and 65 cases (37%) showed the flat type. Intraoperative bleeding was significantly less between 2007 and 2008, in which the operations were performed without first making a 3D anatomy study, than in 2009, in which 3D anatomy studies were made and analyzed before surgery in all patients.

CONCLUSIONS

Dual-phase 3D CT is a useful and essential modality to visualize the precise anatomy around the stomach. As a result, by comparing 3D CT images with our classifications, it is believed that any surgeons may reduce the degree of intraoperative blood loss.

Postoperative recurrence of an IPMN of the pancreas with a fistula to the stomach

We report on a case of a 74 year old man who was diagnosed with a recurrence of non-invasive carcinoma of intraductal papillary mucinous neoplasm (non-invasive IPMN) by postoperative gastroscopy (GS). A pylorus preserving pancreatico duodenectomy for IPMN in the pancreatic head was performed. A histopathological study revealed non-invasive adenocarcinoma. At first, the local recurrence of the tumor around the superior mesenteric artery circumference was diagnosed and disappeared with gemcitabine. Later, the GS showed the elevated lesion with mucin hypersecretion in the remnant stomach. The lesion had a central dip and a fistula common to the pancreas was confirmed on fisterography. We diagnosed a recurrence of IPMN and administered chemotherapy again. However, he died of his original illness. There are no reports of postoperative recurrence of IPMN checked by GS. It should be remembered that the elevated lesion of the remnant stomach is considered as one of the recurrent patterns of IPMN.

Salivary amylase activity is useful for assessing perioperative stress in response to pain in patients undergoing endoscopic submucosal dissection of gastric tumors under deep sedation

BACKGROUND

Although endoscopic submucosal dissection (ESD) for patients with gastric tumors under the conditions of unconsciousness is considered to be minimally invasive, no objective assessment of the perioperative stress of ESD has yet been conducted. Today, stress levels can be easily and objectively assessed by monitoring salivary amylase activity (sAMY). We evaluated the perioperative changes in the sAMY in patients undergoing ESD and identified the causes of such changes.

METHODS

A total of 40 patients with gastric cancers/adenomas removed by ESD under general anesthesia (GA; n = 20) and under deep sedation (DS; n = 20) were enrolled. sAMY was measured using the enzyme analysis equipment, sAMY Monitor (NIPRO, Osaka, Japan) during the perioperative period of the ESD. Also, all patients were interviewed to determine their subjective stress level, using a questionnaire asking "How did you feel during ESD?", with the choice of responses ranging from "did not wake up at all" to "I was awake and ESD was extremely stressful".

RESULTS

The sAMY of the DS group increased soon after the start of ESD. Meanwhile, that of the GA group decreased just after the ESD started and was maintained at a stable level throughout the ESD. In response to the stress level questionnaire, all of the patients in the GA group and a majority of the patients in the DS group responded, "did not wake up at all".

CONCLUSION

Sympathetic agitation, expressed as an increase of sAMY, was absent in the GA group. Meanwhile, in the DS group, some patients showed high levels of sAMY which went down following the administration of an analgesic agent, thus suggesting that pain caused an elevation in the level of the stress and thereby induced an increase in sAMY. The measurement of sAMY is therefore considered to be useful for the assessment of analgesic status under DS.

154 THE EFFECT OF OXYGEN TENSION ON IN VITRO DEVELOPMENT OF BOVINE EMBRYOS IN POLYDIMETHYLSILOXANE-BASED WELL OF THE WELL DISHES PREPARED UNDER ATMOSPHERIC OR REDUCED AIR PRESSURE

Polydimethylsiloxane (PDMS) is a non-toxic silicon compound. Its excellent optical characteristics and easy preparation make it a good candidate material for the molding of custom-shaped dishes for embryo culture. We investigated the feasibility of PDMS-based well of the well (WOW) dishes for in vitro culture of bovine embryos under different oxygen tensions. The WOW dishes with 25 micro-wells (each of 175 μm depth and 250 μm width in diameter arranged in 5 columns and 5 rows) were molded from PDMS prepared either under atmospheric (Experiment 1) or reduced (0.1 MPa) (Experiment 2) air pressure to remove air bubbles. Presumptive zygotes obtained by the in vitro maturation and fertilization of follicular oocytes were placed and cultured for 7 days in traditional micro-drops of culture medium (Control) or in the micro-wells of PDMS-based WOW dishes (PDMS-WOW), both covered by paraffin oil. The culture medium was CR1aa supplemented with 5% calf serum. The culture drop size was 125 μL (5 μL/oocyte) in both groups. Embryo development and blastocyst cell numbers between Control and PDMS-WOW groups were compared either under 20% or 5% O2 tensions. There was no statistical difference in cleavage and blastocyst rates (ranging between 82.3-86.4% and 34.0-45.8%, respectively) between Control and PDMS-WOW embryos irrespective of oxygen tension and dish production method. In Experiment 1, the mean total cell numbers in blastocysts were lower in the PDMS-WOW group than that in Control under 20% O2 (105.0 ± 5.5 and 130.4 ± 9.9, respectively) (P < 0.05, ANOVA); however, the application of 5% O2 significantly improved the cell numbers and eliminated the difference between the PDMS-WOW and Control groups (135.4 ± 6.2 and 148.0 ± 9.0, respectively). In Experiment 2, there was no significant difference in mean total cell numbers in blastocysts between the PDMS-WOW and Control either under 20% O2 (97.2 ± 5.7 and 103.9 ± 8.9, respectively) or 5% O2 (147.5 ± 12.1 and 157.3 ± 3.9, respectively). The numbers and rates of inner cell mass and trophectoderm cells did not differ between the Control and PDMS-WOW groups, irrespective of O2 tension and production method. Our results demonstrate that bovine embryos can develop to the blastocyst stage in PDMS-based WOW dishes; however, it may express detrimental effects on embryonic cell numbers, which can be neutralized by the application of low O2 tension during culture or reduced air pressure during the PDMS preparation. This work was supported by the Research and Development Program for New Bio-Industry Initiatives.

Early primary duodenal carcinoma arising from Brunner's glands synchronously occurring with sigmoid colon carcinoma: report of a case

We herein report a case of early primary duodenal carcinoma arising from Brunner's glands synchronously occurring with sigmoid colon carcinoma. A 65-year-old man with a 5-year history of diabetes mellitus and benign prostatic hypertrophy was admitted to our hospital to undergo a resection of sigmoid colon carcinoma in December 2000. Upper gastrointestinal endoscopy, which was performed as routine preoperative screening, revealed an elevated submucosal-tumor-like lesion with a shallow central depression in the anterior wall of the duodenal bulb. A partial duodenectomy with a partial gastrectomy including No. 5 and No. 6 lymph node dissection and a sigmoidectomy were thus performed. The patient's postoperative course was uneventful. The histopathology of the resected duodenal specimen revealed the tumor to be an adenocarcinoma arising from Brunner's glands. The patient has remained disease-free and has shown no relapse for 6 years postoperatively. Because duodenal carcinoma arising from Brunner's glands is very rare, we report our case with a review of 25 similar documented cases.

Helicobacter pylori induces mono-(adenosine 5'-diphosphate)-ribosylation in human gastric adenocarcinoma

Mono-(adenosine 5'-diphosphate) (ADP)-ribosylation, which transfers an ADP-ribose from nicotinamide adenine dinucleotide (NAD) to an acceptor protein, is an important post-translational modification of cellular proteins. Several bacterial toxins are known to possess the mono-ADP-ribosyltransferase activity to catalyze this reaction as a possible pathogenic factor. Therefore, the aim of this study was to examine whether H. pylori may also induce mono-ADP-ribosylation in a human gastric mucosal protein in association with gastric cancer development. Tumorous and adjacent non-tumorous mucosal tissue specimens were obtained from the surgically removed stomachs of 5 patients with gastric adenocarcinoma, and then were homogenized into cytosolic and membranous fractions. Each homogenate or an H. pylori extract was assayed for mono-ADP-ribosylation with [adenylate-(32)P]-NAD and 3-aminobenzamide, a potent inhibitor of poly-ADP-ribosylation. The radiolabeled proteins were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis followed by radio-image analysis. In the extracts from H. pylori, a strain-dependent, endogenous radiolabeling of 70-kDa protein was detected. An assay of the membranous fractions from 5 gastric adenocarcinomas with the extract of OMH4, a clinical H. pylori isolate, revealed notable radiolabelings of 55- and 45-kDa proteins, which were not found without the OMH4 extract. In contrast, the radiolabelings were minimal in the membranous fractions from respective non-tumorous mucosae, and they were not detected in any of the examined cytosolic fractions. All three radiolabelings of 70-, 55-, and 45-kDa proteins were dependent on NAD, but not on ADP-ribose. Snake venom phosphodiesterase digestion of the 3 radiolabeled proteins released only AMP. We thus found that H. pylori had an enzymatic mono-ADP-ribosyltransferase activity which enabled it to modify the 55- and 45-kDa membranous proteins of human gastric adenocarcinoma, as well as the 70-kDa protein of H. pylori itself. The possible roles underlying our observations on carcinogenesis or development of human gastric carcinoma are yet to be elucidated.

High en bloc resection rate achieved by endoscopic mucosal resection with IT knife for early gastric cancer

BACKGROUND/AIMS

Circumferential endoscopic mucosal resection (EMR) around lesions performed by an insulation-tipped diathermic knife (IT knife) increases en bloc resection rates, suggesting the possibility of expanding indications for EMR.

METHODOLOGY

Clinical outcome of EMR performed by IT knife under general anesthesia was evaluated for 26 patients with 29 early gastric cancer.

RESULTS

Successful en bloc resection rates obtained by the IT knife were 100, 87.5, 90.0 and 100% for lesions < or =10 mm in size, 11-20 mm, 21-30 mm, and > or =31 mm, respectively. They were significantly higher with the IT knife than those obtained by the conventional method (IT knife method: 93.1% vs. conventional method: 28.5%, p<0.0001). Two lesions were lateral margin positive, and in three cases invasion of lesions was observed as deep as the submucosa. Distal, total, and proximal gastrectomy with D2 lymphadenectomy, respectively, was provided in 3 cases; however, no lymph node involvement was found in any of the resected specimens. Bleeding and perforation were observed in 3 cases, respectively, however, no additional surgical treatment was required for these patients.

CONCLUSIONS

EMR by means of the IT knife under general anesthesia can be performed safely and adequately. It is a useful treatment modality for early gastric cancer.

Treatments of hamartoma with neuroendoscopic surgery and stereotactic radiosurgery: a case report

Hypothalamic hamartoma is a non-neoplastic tumor manifesting as gelastic seizure, precocious puberty, and abnormal behavior. Treatment of it is very complicated due to its location. We report a case of hypothalamic hamartoma treated by neuroendoscopic surgery and stereotactic radiosurgery. A 5-year-old girl presented with violent behavior, precocious puberty, gelastic seizure and atonic seizure. She was diagnosed with hypothalamic hamartoma by CT and magnetic resonance imaging at 11 months of age. Tumor size did not change, but tumor intensity had changed on the MR image at 5 years of age. Magnetic resonance spectroscopy revealed decreased N-acetylaspartate and increased choline and creatine in the tumor. After neuroendoscopic biopsy, she underwent linear accelerator stereotactic radiosurgery. But her symptoms remained unchanged for 6 months. She then underwent partial resection and laser coagulation of the tumor by a neuroendoscopic approach. After the procedure, the frequency of her seizures was remarkably decreased, and her violent behavior improved. The transventricular neuroendoscopic approach to the hypothalamus is less invasive than the radical surgery. Neuroendoscopic surgery can be one of the treatments of choice for hypothalamic hamartoma.

A silver-containing halogen-free inorganic photochromic glass

A halogen-free inorganic photochromic soda-lime silicate glass containing silver ions has been developed; reversible change between colorless and yellow color in this glass is achieved through combined 193 nm excimer laser irradiation and heat treatment.

Report of changing signal intensity on follow-up MRI in a case of hypothalamic hamartoma

We present a case of hypothalamic hamartoma in which the signal intensity of the lesion significantly changed during the course of follow-up. To date, stability of the lesion morphology over time has been considered an important diagnostic criterion of hypothalamic hamartoma. Radiologists should be aware that in hypothalamic hamartoma, signal intensity can change during its natural course.

Chordoid glioma of the third ventricle: CT and MR findings

We present a case of chordoid glioma involving the third ventricle in a 42-year-old woman. CT and MR showed a homogeneously enhancing mass occupying the third ventricle, with a cystic component. Chordoid glioma should be included in the differential diagnosis of uncommon masses of the third ventricle in middle-aged women.

Transformation of fibrolamellar carcinoma to common hepatocellular carcinoma in the recurrent lesions of the rectum and the residual liver: a case report

A 21-year-old man had undergone central bisegmentectomy of the liver due to fibrolamellar carcinoma (FLC). Twice, 24 and 30 months after the first operation, lymph node metastases were removed. We have reported this case previously and this is the second report of the same case. Forty-two months after the second operation to remove lymph node metastases, a recurrence occurred in the rectum and was excised. However, the tumor also recurred in the residual liver. The patient underwent hepatectomy for a palliative purpose but died 16 months after the last operation. Histopathologically, the primary tumor was diagnosed as pure FLC, but the lymph node metastases had foci of the common hepatocellular carcinoma (HCC) mixed with FLC. In contrast, the recurrent tumors in the rectum and the residual liver showed the histopathological features of common HCC. Thus, during repeated recurrences, histopathological features changed from pure FLC to common HCC.

Migrated disc in the lumbar spinal canal--case report

A 49-year-old man who had complained of back pain for 20 years presented with numbness and pain in his left leg persisting for 6 weeks. Magnetic resonance imaging demonstrated a peripherally enhanced intraspinal mass at the L-3 level. The mass was completely removed. The operative and histological findings revealed degenerated disc fragments surrounded by granulation tissue. His symptoms were completely relieved. Migrated disc should be included in the differential diagnosis of patients with a long history of back pain and an intraspinal mass.

Post-stroke treatment with imidapril reduces learning deficits with less formation of brain oedema in a stroke-prone substrain of spontaneously hypertensive rats

The present study was undertaken to examine the effects of the ACE (angiotensin converting enzyme) inhibitor imidapril, on the brain, when administered after the onset of stroke in a stroke-prone substrain of spontaneously hypertensive rats (SHRSP). Learning deficits and induced lesions in the brain as well as in the kidneys and heart were investigated in detail. SHRSP were divided into two groups with or without salt loading at the age of 4 weeks. The salt loading was performed for 7-9 weeks to increase the incidence of stroke. Within 24 h after the first observation of stroke, animals were subsequently treated with 5 mg/kg imidapril orally once a day or the vehicle for up to the age of 27 weeks. Imidapril attenuated progression of neurological abnormalities such as irritability, hyperkinesia and motor dysfunction, and increased survival rate. In three-panel runway testing, learning deficits did not develop significantly in the imidapril-treated group, and was comparable to that in the non-salt-loaded/non-stroke group. Imidapril reduced oedema formation in the cortex, hippocampus and striatum, and also suppressed lesion formation in the kidneys and heart. Imidapril thus suppressed progression of neurological deficits with loss of learning ability following onset of stroke, and also suppressed formation of oedema in the brain and decreased the number of lesions in other organs. Imidapril-induced reduction of cerebrovascular damage, which presumably occurs in the brain after stroke, may account for the inhibitory effects of imidapril on lesion formation and learning impairment.

Extraneural metastasis of intracranial germinoma with syncytiotrophoblastic giant cells--case report

A 14-year-old boy presented with an extraneural metastasis of germinoma with syncytiotrophoblastic giant cells (STGC). The tumor was located in the pineal area, suprasellar cistern, and frontal base, and associated with the slight elevation of the beta-human chorionic gonadotropin (HCG) serum level. Following radiation therapy, the tumor completely disappeared, and the beta-HCG level decreased to normal. Two years after the initial treatment, metastasis of the tumor to the left femur was observed without recurrence of the primary lesion. The biopsy specimen revealed germinoma, the diagnosis was germinoma with STGC because of the associated elevation of HCG level. The metastatic tumor was treated by chemotherapy with cisplatin and etoposide, and the tumor completely disappeared. With adjuvant chemotherapy, he has been recurrence-free for 3 years. Extraneural metastasis occurs more frequently from germinoma with STGC than germinoma. Aggressive chemotherapy combined with radiation therapy in the initial treatment might have to be tried to avoid metastasis from germinoma with STGC.

Treatment of chronic subdural hematoma by closed-system drainage without irrigation

BACKGROUND

Recurrence of chronic subdural hematoma after surgery has not been eliminated. We sought to determine whether irrigation influences recurrence rate.

METHODS

Patients who had undergone surgery for chronic subdural hematoma were reviewed retrospectively.

RESULTS

Between 1986 and 1993, 186 cases of chronic subdural hematoma were treated surgically at Mito National Hospital. Recurrence was limited to six cases (3.2%). A closed drainage system without irrigation has been used since 1988 in 119 patients. Before 1988, 67 cases were treated with single burr hole irrigation and drainage. The rate of recurrence with the closed drainage system was 3.4% (four cases), compared with 3.0% (two cases) for irrigation and drainage.

CONCLUSION

Compared with irrigation and drainage, the closed drainage system without irrigation was safe and effective, and recurrence of chronic subdural hematoma is not influenced by irrigation.

Primitive neuroectodermal tumor in the spinal epidural space--case report

A 4-year-old boy presented with a rare case of an epidural tumor causing compression of the thoracic spinal cord manifesting as rapid worsening of gait disturbance. The tumor was grossly totally resected, and radiotherapy and chemotherapy were subsequently administered. The histological diagnosis was primitive neuroectodermal tumor. He has been free of recurrence for more than 6 years. Early tumor resection followed by chemotherapy and irradiation is recommended for patients with primitive neuroectodermal tumor and unstable symptoms.

Nontraumatic convexity intradiploic arachnoid cyst

A 63-year-old male presented with an unusual case of nontraumatic intradiploic arachnoid cyst in the frontotemporal convexity area. Skull radiography showed a circular osteolytic lesion of the right parietal bone. Computed tomography revealed a defect of the inner table, widened diploic space, and thinned outer table. Magnetic resonance imaging showed a cyst containing cerebrospinal fluid. Bone scintigraphy showed no abnormal uptakes. Intraoperative observation confirmed the neuroimaging findings. Histological examination found no abnormal findings in specimens of skull bone or arachnoid membrane. Intradiploic arachnoid cyst is characterized by parasagittal, multiple, well-demarcated osteolytic lesions on radiographs in the elderly. However, the clinical features of this disease remain unclear and diagnosis without an exploratory surgical procedure may not be possible.

Pseudo-cerebrospinal fluid rhinorrhea after skull base surgery

A 41-year-old female underwent complete resection of a left petroclival meningioma via an anterior transpetrosal approach, during which the greater superficial petrosal nerve was divided. On the 14th day after the operation, she first noticed leakage of clear fluid from her right nostril whenever the ambient room temperature rose. This pseudo-cerebrospinal fluid rhinorrhea may have developed because of parasympathetic hypersensitivity due to division of the greater superficial petrosal nerve.

Superior sagittal sinus thrombosis associated with primary antiphospholipid syndrome--case report

A 36-year-old female with a history of recurrent pregnancy loss experienced sudden onset of disturbance in consciousness, with right hemiparesis and total aphasia. Computed tomography revealed a massive hemorrhage in the left frontal lobe, and angiography showed occlusion of the anterior two-thirds of the superior sagittal sinus. Laboratory investigations detected the presence of lupus anticoagulant, elevation of the anticardiolipin beta 2-glycoprotein I complex antibody level, and a decreased protein S activity level. There were no underlying conditions, such as connective tissue disorders, malignancies, infectious diseases, and drug-induced disorders, so the diagnosis was primary antiphospholipid syndrome. Primary antiphospholipid syndrome should be considered in the evaluation of patients with "idiopathic" or "primary" sinus and cerebral venous thrombosis.

Results of urgent thrombolysis in patients with major stroke and atherothrombotic occlusion of the cervical internal carotid artery

PURPOSE

Atherothrombotic occlusion of the cervical internal carotid artery (ICA) without collateral flow is one of the most critical forms of acute ischemia. We report the results of urgent thrombolytic treatment of patients with major stroke in this clinical category.

METHODS

Clinical findings and outcome in 33 patients were investigated. All patients had suffered a major stroke, with a score of 24 or higher on the NIH Stroke Scale on admission. Ischemic abnormalities were not detected on initial CT studies. Diagnoses were made at angiography, and patients were treated by intravenous or intraarterial local thrombolysis within 6 hours of stroke onset.

RESULTS

Recanalization was accomplished in eight patients with intraarterial local thrombolysis; four of these patients had a good clinical outcome. Two factors characteristic of those whose treatment was successful were dramatic improvement of symptoms after partial recanalization achieved within 3 hours of onset and stabilized improvement after subsequent percutaneous transluminal angioplasty or carotid endarterectomy for residual atherosclerotic stenosis at the ICA origin.

CONCLUSION

The results of this study suggest that urgent intraarterial local thrombolysis may be a successful treatment method for some patients in this critical clinical category if the treatment can be accomplished within 3 hours of ictus and followed by either angioplasty or endarterectomy for residual stenosis.

Pitfalls in endovascular treatment of dural arteriovenous fistulas involving the cavernous sinus

SUMMARY

Angiographic changes of the sylvian veins, superior ophthalmic vein (SOV), and superior petrosal sinus (SPS) before and after endovascular treatment were determined for 18 patients with dural arteriovenous fistulas (AVFs) involving the cavernous sinus, and pitfalls of endovascular treatment, especially regarding venous drainage routes, for 3 of the patients were reported. Case 1: 57-year-old woman who presented with right abducens nerve palsy had a Barrow type D fistula in the right cavernous sinus draining into the bilateral inferior petrosal sinuses (IPS). One of the ipsilateral sylvian veins that had drained antegradely before treatment was occluded, and a small lacunar infarction in the corona radiata developed after transvenous embolization (TVE) of the right cavernous sinus. Case 2: 72-year-old woman who presented with symptoms of right ocular hypertension had a type D fistula in the right cavernous sinus draining into only the ipsilateral SOV. Conjunctival hyperemia persisted and was aggravated after angioanatomical obliteration of the fistula by transarterial embolization. Case 3: 55-year-old man who presented with left abducens nerve palsy had a type D fistula in the left cavernous sinus draining into the ipsilateral IPS and sylvian vein. The dural AVF was obliterated once with TVE, but recurred 1 week later with retrograde drainage into the ipsilateral SPS and mesencephalic veins. A second TVE resulted in complete obliteration of the fistula. In conclusion, detailed analysis of drainage routes is necessary for planning of treatment of patients with dural AVF, and prompt treatment is needed when redistribution of drainage routes develops during or after TVE.

Thrombin reduces large heparan sulfate proteoglycan molecules in cultured vascular endothelial cell layers through inhibition of core protein synthesis

We investigated the alteration of heparan sulfate proteoglycans induced by thrombin in cultured vascular endothelial cells. Heparan sulfate proteoglycans, which were metabolically labeled with [3H] glucosamine and [35S] sulfate, were isolated by DEAE-Sephacel ion-exchange chromatography and characterized by molecular sieve gel filtration. Core proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of [35S] amino acids-labeled heparan sulfate proteoglycans after digestion with hepartinase. It was revealed that the high molecular weight subclass of heparan sulfate proteoglycans in the cell layer was markedly decreased by thrombin without changes of the hydrodynamic size of the molecules and the molecular weight of heparan sulfate chains. In addition, thrombin decreased the amount of large heparan sulfate proteoglycan core protein with a molecular weight of approximately 400 kDa, probably perlecan core, in the cell layer and the conditioned medium. The present data suggest that thrombin-induced decrease in the amount of heparan sulfate in vascular endothelial cell layer includes a reduction of the number of large heparan sulfate proteoglycan perlecan molecules through a suppression of the core protein synthesis.