Virtual reality with three-dimensional image guidance of individual patients' vessel anatomy in laparoscopic distal pancreatectomy.

PURPOSE: Three-dimensional virtual endoscopy (3DVE) has the potential advantage of enhanced anatomic delineation and spatial orientation during laparoscopic procedures. In the present study, we aimed to evaluate the impact of 3DVE guidance in laparoscopic distal pancreatectomy (LDP). METHODS: Thirty-eight patients presenting to our hospital with a variety of pancreatic tumors underwent preoperative computed tomography scanning to clearly define the major peripancreatic vasculature and correlate it with a 3DVE system (SYNAPSE VINCENT: Fujifilm Medical, Tokyo, Japan). This map served as the guide during preoperative planning, surgical education, and simulation and as intraoperative navigation reference for LDP. Operative records and pathological findings were analyzed for each procedure. Operative parameters were compared between the 38 patients in this study and 8 patients performed without 3DVE guidance at our institution. RESULTS: The 3DVE navigation system successfully created a preoperative resection map in all patients. Relevant peripancreatic vasculature displayed on the system was identified and compared during the intervention. The mean blood loss in LDP performed under 3DVE guidance versus LDP without 3DVE was 168.5 +/- 347.6 g versus 330.0 +/- 211.4 g, p = 0.008 while and the operative time was 171.9 +/- 51.7 min versus 240.6 +/- 24.8 min, p = 0.001. CONCLUSIONS: 3DVE in conjunction with a "laparoscopic eye" creates a preoperative and intraoperative three-dimensional data platform that potentially enhances the accuracy and safety of LDP.

Imbalance Between Salivary Cortisol and DHEA Responses Is Associated with Social Cost and Self-perception to Social Evaluative Threat in Japanese Healthy Young Adults.

BACKGROUND: Social evaluative threat activates the HPA-axis system, namely cortisol and dehydroepiandrosterone (DHEA) responses. Additionally, cognitive and behavioral models in social anxiety, which is aroused anxiety symptoms in social situations, indicate that negative cognitions have a role in the maintenance of symptoms. Thus, the present study examined the relationship between HPA-axis activity and cognitive features in social situations. METHOD: We conducted the Trier Social Stress Test (TSST) with 44 male participants and assessed HPA-axis responses, fear of negative evaluation, the estimated social cost, and self-perceptions of their speech performance, which are core negative cognitions in social situations. RESULTS: Results revealed that the cortisol-DHEA ratio significantly correlated with self-perceptions of participants' speech performance (r = .30, p = .044) and the discrepancy between self-ratings and others' ratings of the speech (r = .44, p = .003). After controlling for depressive symptoms, significant correlations remained (r = .39, p = .01 and r = .50, p = .001, respectively). In addition, the estimated social cost, assessed before the speech task, significantly correlated with both the AUCg cortisol (r = .38, p = .011) and cortisol-DHEA ratios (r = .40, p = .007). CONCLUSION: These results suggest that estimating social costs in social situations, as well as distorted self-perceptions of that stressor, is related to dysfunctional endocrine regulation.

Improvement of Psoriasis by Alteration of the Gut Environment by Oral Administration of Fucoidan from Cladosiphon Okamuranus.

Psoriasis is a chronic autoimmune inflammatory disease for which there is no cure; it results in skin lesions and has a strong negative impact on patients' quality of life. Fucoidan from Cladosiphon okamuranus is a dietary seaweed fiber with immunostimulatory effects. The present study reports that the administration of fucoidan provided symptomatic relief of facial itching and altered the gut environment in the TNF receptor-associated factor 3-interacting protein 2 (Traf3ip2) mutant mice (m-Traf3ip2 mice); the Traf3ip2 mutation was responsible for psoriasis in the mouse model used in this study. A fucoidan diet ameliorated symptoms of psoriasis and decreased facial scratching. In fecal microbiota analysis, the fucoidan diet drastically altered the presence of major intestinal opportunistic microbiota. At the same time, the fucoidan diet increased mucin volume in ileum and feces, and IgA contents in cecum. These results suggest that dietary fucoidan may play a significant role in the prevention of dysfunctional immune diseases by improving the intestinal environment and increasing the production of substances that protect the immune system.

[Present and Future of Navigation Surgery in Hepatobiliary and Pancreatic Surgery].

Hepatobiliary and pancreatic surgery is recognized as technically demanding due to the complicated local anatomy and diverse anatomical variation that require precise techniques. Therefore, preoperative simulation to understand the detailed local anatomy and intraoperative navigation methods for surgical guidance are needed. Intraoperative navigation for anatomical hepatectomy originated with dye injection into the dominant portal pedicle under intraoperative ultrasound guidance to identify hepatic segments, which was reported by Makuuchi et al in 1985. In recent years, with advancing medical technology, newer medical devices that promote the safety and reliability of various surgical procedures have been developed. In this article, we will discuss the current state and future prospects of intraoperative navigation in hepatobiliary and pancreatic surgery.

Insulin augments serotonin-induced contraction via activation of the IR/PI3K/PDK1 pathway in the rat carotid artery.

Hyperinsulinemia associated with type 2 diabetes may contribute to the development of vascular diseases. Although we recently reported that enhanced contractile responses to serotonin (5-hydroxytryptamine, 5-HT) are observed in the arteries of type 2 diabetes models, the causative factors and detailed signaling pathways involved remain unclear. The purpose of this study was to investigate whether high insulin would be an amplifier of 5-HT-induced contraction in rat carotid arteries and whether the contraction involves phosphoinositide 3-kinase (PI3K)/3-phosphoinositide-dependent protein kinase 1 (PDK1) signaling, an insulin-mediated signaling pathway. In rat carotid arteries organ-cultured with insulin (for 24 h), (1) the contractile responses to 5-HT were significantly greater (vs. vehicle), (2) the insulin-induced enhancement of 5-HT-induced contractions was largely suppressed by inhibitors of the insulin receptor (IR) (GSK1838705A), PI3K (LY294002), and PDK1 (GSK2334470), and (3) the levels of phosphorylated forms of both PDK1 and myosin phosphatase target subunit 1 (MYPT1) were greater upon 5-HT stimulation. In addition, in rat carotid arteries organ-cultured with an activator of PDK1 (PS48), the 5-HT-induced contraction was greater, and this was suppressed by PDK1 inhibition but not PI3K inhibition. In addition, MYPT1 and PDK1 phosphorylation upon 5-HT stimulation was enhanced (vs. vehicle). These results suggest that high insulin levels amplify 5-HT-induced contraction. Moreover, the present results indicated the direct linkage between IR/PI3K/PDK1 activation and 5-HT-induced contraction in rat carotid arteries for the first time.

Mechanisms Underlying Enhanced Noradrenaline-Induced Femoral Arterial Contractions of Spontaneously Hypertensive Rats: Involvement of Endothelium-Derived Factors and Cyclooxygenase-Derived Prostanoids.

We investigated the relationship between noradrenaline (NAd)-induced contractions, endothelial function, and hypertension in femoral arteries isolated from spontaneously hypertensive rats (SHR). In the femoral arteries of SHR, vs. age-matched control Wistar Kyoto (WKY) rats, contractions induced by NAd were increased. These effects were enhanced by endothelial denudation, which abolished the differences between the two groups. NAd-induced contractions were enhanced by nitric oxide (NO) synthase inhibition, and further increased by the blockade of endothelium-derived hyperpolarizing factor (EDHF). Conversely, NAd-induced contractions were inhibited by cyclooxygenase (COX) inhibition. In addition, in SHR arteries, acetylcholine-induced relaxation was reduced, and components of endothelium-derived factors were altered, such as increased COX-derived vasoconstrictor prostanoids, reduced EDHF, and preserved NO-mediated relaxation. In the femoral arteries of SHR, the production of prostanoids [6-keto prostaglandin (PG)F1α (a metabolite of prostacyclin (PGI2), PGE2, and PGF2α] and COX-2 protein were increased compared with that in WKY rats. By contrast, contractions induced by beraprost (a stable PGI2 analogue), PGE2, and U46619 (thromboxane/prostanoid receptor agonist) were similar between the SHR and WKY groups. Thus, NAd-induced femoral arterial contractions are augmented in SHR resulting from endothelial dysfunction and increased COX-derived vasoconstrictor prostanoid levels.

Routes for virtually guided endoscopic liver resection of subdiaphragmatic liver tumors.

PURPOSE: Laparoscopic and thoracoscopic/laparoscopic hepatectomy is a safe procedure that has potential advantages over open surgery. However, deeply positioned liver tumors require expert laparoscopic and thoracoscopic/laparoscopic hepatectomy techniques. Using simulated preoperative three-dimensional virtual endoscopy (P3DVE) guidance, we demonstrate herein that a thoracoscopic approach (TA), thoracoscopic-laparoscopic approach (TLA), and laparoscopic approach (LA) are all feasible and safe routes for performing pure laparoscopic and thoracoscopic/laparoscopic resection of liver tumors located in the 4a, 7, and 8 liver subdiaphragmatic areas. METHODS: Thirty-eight patients underwent laparoscopic and thoracoscopic/laparoscopic partial liver resection (TA 13 cases, TLA two cases, and LA 23 cases) of the subdiaphragmatic area at Showa University Hospital. All surgical approaches were preoperatively determined based on preoperative 3D virtual endoscopic simulation (P3DVES) visualization and findings using the image processing software SYNAPSE VINCENT(®). RESULTS: Laparoscopic and thoracoscopic/laparoscopic liver resection was successfully performed for all cases under P3DVE instruction. The mean operative times using TA, TLA, and LA approaches were 193, 185, and 190 min, respectively. Mean blood loss during TA, TLA, and LA was 179, 138, and 73 g, respectively. No patients required conversion to open surgery, and there were no deaths, although there were three cases of Clavien-Dindo grade I in TA along with three cases of grade I and one case of grade II in LA. CONCLUSIONS: TA, TLA, and LA routes performed under P3DVE instruction are feasible and safe to perform for pure laparoscopic and thoracoscopic/laparoscopic liver resection in selected patients with lesions located in the hepatic subdiaphragmatic area.

Stress Underestimation and Mental Health Outcomes in Male Japanese Workers: a 1-Year Prospective Study.

PURPOSE: Being appropriately aware of the extent of stress experienced in daily life is essential in motivating stress management behaviours. Excessive stress underestimation obstructs this process, which is expected to exert adverse effects on health. We prospectively examined associations between stress underestimation and mental health outcomes in Japanese workers. METHODS: Web-based surveys were conducted twice with an interval of 1 year on 2359 Japanese male workers. Participants were asked to complete survey items concerning stress underestimation, depressive symptoms, sickness absence, and antidepressant use. RESULTS: Multiple logistic regression analysis revealed that high baseline levels of 'overgeneralization of stress' and 'insensitivity to stress' were significantly associated with new-onset depressive symptoms (OR = 2.66 [95 % CI, 1.54-4.59], p < .01) and antidepressant use (OR = 4.91 [95 % CI, 1.22-19.74], p < .05), respectively, during the 1-year follow-up period. CONCLUSIONS: This study clearly demonstrated that stress underestimation, including stress insensitivity and the overgeneralization of stress, could exert adverse effects on mental health.

Effects of hyperbaric exposure on thrombus formation.

BACKGROUND: Hyperbaric oxygen (HBO2) therapy has a long history of use. However, its effect on thrombus formation is unclear. Many reports have indicated that it accelerates platelet aggregation, which suggests that it may increase thrombotic events. However, clinical trial results are inconsistent, and no previous reports have demonstrated that HBO2therapy does in fact increase thrombotic events. Here, we used a total thrombus formation analysis system (T-TAS) to analyze changes in thrombus formation in a specimen group exposed to constant hyperbaric pressure in vitro, and a control group. METHODS: Blood samples were collected from two sets of 10 healthy volunteers (mean age, 28.8 years) with no underlying disease. In the pressurized group, a constant pressure was applied to specimens in temperature-controlled test tubes; the non-pressurized group served as the control. Thrombus formation in samples from both the pressurized and control groups were measured using the T-TAS immediately, 20 minutes, and 40 minutes after pressurization. RESULTS: In the pressurized group, the onset of thrombus formation was significantly delayed, confirming a reduction in thrombus formation ability. However, the reduced ability for thrombus formation in the pressurized group recovered to the level of the control group. That is, the change in thrombus formation ability caused by pressure was proven to be reversible. CONCLUSIONS: We are the first to ascertain a decrease in the thrombus formation ability in specimens exposed to hyperbaric pressure using a T-TAS, which is capable of measuring thrombus formation in an environment similar to that in vivo.

Relaxation Induced by Atrial Natriuretic Peptide Is Impaired in Carotid but Not Renal Arteries from Spontaneously Hypertensive Rats Due to Reduced BKCa Channel Activity.

Atrial natriuretic peptide (ANP) plays an important role in vascular functions such as blood pressure regulation and relaxant activity. Individual vascular beds exhibit differences in vascular reactivity to various ligands, however, the difference in responsiveness to ANP between carotid and renal arteries and the molecular mechanisms of its vasorelaxant activity in a pathophysiological state, including hypertension, remain unclear. We therefore investigated this issue by exposing carotid and renal artery rings obtained from spontaneously hypertensive rats (SHR) to ANP. In the SHR artery (vs. control WKY artery), the ANP-induced relaxations were reduced in carotid artery but not renal artery. Acetylcholine-induced relaxations were reduced in both arteries in SHR (vs. WKY). Sodium nitroprusside-induced relaxation was similar in both arteries between the groups. In carotid arteries, the ANP-induced relaxation was not affected by endothelial denudation or by treatment with inhibitors of nitric oxide synthase, cyclooxygenase, the voltage-dependent potassium channel, or ATP-sensitive potassium channel in arteries from both SHR and WKY. In the carotid artery from WKY but not SHR, the ANP-induced relaxation was significantly reduced by inhibition of the large-conductance calcium-activated potassium channel (BKCa). The BKCa activator-induced relaxation was reduced in the SHR artery (vs. WKY). These results suggest that ANP-induced relaxation is impaired in the carotid artery from SHR and this impairment may be at least in part due to the reduction of BKCa activity rather than endothelial components.

Risk factors for bowel necrosis in patients with hepatic portal venous gas.

PURPOSE: To evaluate the risk factors for bowel necrosis in adult patients with hepatic portal venous gas (HPVG). METHODS: This retrospective study comprised 33 adult patients treated for HPVG between August, 2008 and December, 2011. The patients were divided into a necrotic group (n = 14) and a non-necrotic group (n = 19). We analyzed the clinical demographics, laboratory data, multi-detector computed tomography findings, treatments, and outcomes in each group. RESULTS: Abdominal pain, peritoneal signs, systolic blood pressure, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase (LDH), small intestinal dilatation, poor enhancement of the bowel wall, and intestinal pneumatosis were all significantly associated with bowel necrosis. Moreover, there were significantly more operative cases and deaths in the necrotic group. Multivariate analysis revealed that systolic BP (p = 0.048), LDH (p = 0.022), and intestinal pneumatosis (p = 0.038) were independent risk factors for bowel necrosis. Thus, we created new diagnostic criteria for bowel necrosis based on these three factors, the sensitivity, specificity, and accuracy of which were 100, 78.9, and 87.9 %, respectively. CONCLUSIONS: This study demonstrates new and important findings to evaluate the risk factors for bowel necrosis. Using our diagnostic criteria, the indications for emergency laparotomy can be established more accurately.

[Development of a measure to assess stress underestimation beliefs].

Stress estimation is involved in the production of stress management behavior. Stress underestimation could hinder efforts to adequately manage stress. This study developed a measure to assess stress underestimation beliefs. Questionnaire surveys were conducted by mail twice on 2,340 adults aged from 20 to 65 years. The data from the surveys were subject to factor analysis, from which we developed a 12-item scale to assess stress underestimation beliefs (SUB). The SUB included four subscales: "Excessive self-efficacy for managing stress," "Insensitivity to stress," "Overgeneralization of stress," and "Evasive attitude towards stress." The SUB had adequate internal consistency. Higher SUB scores were associated with being in the precontemplation stage of change in terms of stress management behaviors, working long overtime hours (more than 81 hours per month), and having fewer self-reported stress symptoms. The SUB is potentially useful for assessing stress underestimation in the context of stress management.

Laparoscopic Anatomical Liver Resection Using Liver Mapping of Incidental Indocyanine Green Fluorescence due to Cholestasis.

BACKGROUND/AIM: Indocyanine green (ICG) fluorescence is useful in laparoscopic hepatectomy (LH) for tumor identification and staining, as well as determination of resection margins. At our Institution, patient-specific, three-dimensional simulations and rehearsal of surgical strategies are carried out preoperatively. We describe cases in which ICG administered preoperatively became stagnated and fluoresced in an area similar to the preoperatively established resection area and the pathological findings in these cases. PATIENTS AND METHODS: Four patients who underwent LH at our hospital between 2020 and 2023 (due to hepatocellular carcinoma in two and colorectal liver metastasis in two) were enrolled in the present study. The ICG-fluorescing liver segments were resected laparoscopically and their pathological characteristics were examined using a fluorescence microscope. RESULTS: In four cases, the areas of ICG fluorescence seen intraoperatively were due to stasis of preoperatively administered ICG, which fortuitously was equivalent to the planned resection area in the preoperative patient-specific simulation. The fluorescent areas were resected; there were no cases of bile leakage or recurrence. Fluorescence microscopy revealed areas with diffuse ICG fluorescence in normal hepatocytes on the tumor's peripheral side. CONCLUSION: It was suggested that resection of the liver area that was fluorescent due to stagnation of preoperatively administered ICG was rational and justified both anatomically and oncologically. This resection may also contribute to the prevention of bile leakage and recurrence.

Cancer-associated fibroblasts reuse cancer-derived lactate to maintain a fibrotic and immunosuppressive microenvironment in pancreatic cancer.

Glycolysis is highly enhanced in pancreatic ductal adenocarcinoma (PDAC) cells; thus, glucose restrictions are imposed on nontumor cells in the PDAC tumor microenvironment (TME). However, little is known about how such glucose competition alters metabolism and confers phenotypic changes in stromal cells in the TME. Here, we report that cancer-associated fibroblasts (CAFs) with restricted glucose availability utilize lactate from glycolysis-enhanced cancer cells as a fuel and exert immunosuppressive activity in the PDAC TME. The expression of lactate dehydrogenase A (LDHA), which regulates lactate production, was a poor prognostic factor for patients with PDAC, and LDHA depletion suppressed tumor growth in a CAF-rich murine PDAC model. Coculture of CAFs with PDAC cells revealed that most of the glucose was taken up by the tumor cells and that CAFs consumed lactate via monocarboxylate transporter 1 to enhance proliferation through the TCA cycle. Moreover, lactate-stimulated CAFs upregulated IL-6 expression and suppressed cytotoxic immune cell activity synergistically with lactate. Finally, the LDHA inhibitor FX11 reduced tumor growth and improved antitumor immunity in CAF-rich PDAC tumors. Our study provides insight regarding the crosstalk among tumor cells, CAFs, and immune cells mediated by lactate and offers therapeutic strategies for targeting LDHA enzymatic activity in PDAC cells.

Indocyanine Green Labeling of Tumors in the Liver Recurring After Radiofrequency Ablation Enables Complete Resection by Fluorescence-guided Surgery.

BACKGROUND/AIM: Radiofrequency ablation (RFA) is used to treat primary and metastatic tumors in the liver. However, local recurrence after RFA is frequent and subsequent salvage hepatectomy is often ineffective due to difficulty in visualization of tumor margins. PATIENTS AND METHODS: In the present retrospective clinical trial, seven patients from the Department of General and Gastro-enterological Surgery, Showa University School of Medicine underwent salvage hepatectomy for recurrent hepatocellular carcinoma (HCC) (n=2), colorectal liver metastasis (n=4) and lung-carcinoid liver metastasis (n=1), after RFA, between 2011 and 2020. Tumors were labeled with indocyanine green (ICG) and resected under fluorescence guidance. Resected specimens were evaluated under fluorescence microscopy as well as by standard histopathological techniques. RESULTS: Pathological findings revealed negative tumor margins in all patients after fluorescence-guided surgery. Six of seven resected tumors had a fluorescent rim, including both HCC and liver metastasis. Fluorescence microscopy demonstrated that viable cancer tumor cells were located only on the inside of the fluorescent rim, and no malignant cells were detected within the fluorescent rim surrounding the tumor. Fluorescence microscopy showed that the tumor margin was secured if the fluorescence signal was completely resected. CONCLUSION: The present results demonstrate that ICG labeling of liver tumors recurring after RFA enabled complete resection under fluorescence guidance. The present study is the first clinical study to demonstrate that tumor types that generally cannot be completely resected with bright light are fully resectable under fluorescence guidance.

Relationship Between Remnant Pancreatic Volume and Endocrine Function After Pancreaticoduodenectomy.

BACKGROUND: Decreased pancreatic volume (PV) is a predictive factor for diabetes mellitus (DM) after surgery. There are few reports on PV and endocrine function pre- and post-surgery. We investigated the correlation between PV and insulin secretion. METHODS: Seventeen patients underwent pancreaticoduodenectomy (PD) Pre- and post-surgery PV and C-peptide index (CPI) measurements were performed. Additionally, the correlation between PV and CPI was analyzed. RESULTS: The mean preoperative PV (PPV) was 55.1 ± 31.6 mL, postoperative remnant PV (RPV) was 25.3±17.3 mL, and PV reduction was 53%. The mean preoperative C-peptide immunoreactivity (CPR) was 1.39 ± .51 and postoperative CPR was .85±.51. The mean preoperative CPI was 1.29±.72 and postoperative CPI was .73 ± .48. Significant correlations were observed between RPV and post CPR (ρ = .507, P = .03) and post CPI (ρ = .619, P = .008). DISCUSSION: There was a significant correlation between RPV and CPI after PD. A smaller RPV resulted in lower insulin secretion ability, increasing the potential risk of new-onset DM after PD.

Cynical hostility, anger expression style, and acute myocardial infarction in middle-aged Japanese men.

Studies using American and European populations have demonstrated that high levels of anger/ hostility are predictive of coronary heart disease (CHD) mortality. However, Japanese studies did not show consistent relationship between anger/hostility and CHD. This study examines the association of cynical hostility and anger expression style with acute myocardial infarction (AMI) in middle-aged Japanese men through a case-control study. The patients with acute myocardial infarction (N = 96, mean age = 50.8 years) and the healthy participants in a health check-up program (N = 77, mean age = 50.3 years) were studied. Both groups completed the Cynicism Questionnaire (CQ) and the State-Trait Anger Expression Inventory (STAXI). The patients exhibited higher scores on CQ than the healthy controls. Logistic regression analyses controlling for biological risk factors revealed that the CQ score was associated with increased risk of AMI (OR = 1.11 [95% CI 1.00-1.22]). In addition, the score of Anger-control, a subscale of STAXI, was associated with decreased risk of AMI (OR = 0.75 [95% CI 0.62-0.92]). These results indicated that higher levels of cynical hostility increased the risk of AMI and that anger-control strategies could have some benefit in reducing the risk of AMI in middle-aged Japanese men.

The Efficacy of Intraoperative Fluorescent Imaging Using Indocyanine Green for Cholangiography During Cholecystectomy and Hepatectomy.

PURPOSE: Bile duct injury is one of the most serious complications of laparoscopic cholecystectomy. Intraoperative indocyanine green (ICG) cholangiography is a safe and useful navigation modality for confirming the biliary anatomy. ICG cholangiography is expected to be a routine method for helping avoid bile duct injuries. PATIENTS AND METHODS: We examined 25 patients who underwent intraoperative cholangiography using ICG fluorescence. Two methods of ICG injection are used: intrabiliary injection (percutaneous transhepatic gallbladder drainage [PTGBD], gallbladder [GB] puncture and endoscopic nasobiliary drainage [ENBD]) at a dosage of 0.025 mg during the operation or intravenous injection with 2.5 mg ICG preoperatively. RESULTS: There were 24 patients who underwent laparoscopic cholecystectomy and 1 patient who underwent hepatectomy. For laparoscopic cholecystectomy, the average operation time was 127 (50-197) minutes, and estimated blood loss was 43.2 (0-400) g. The ICG administration route was intravenous injections in 12 cases and intrabiliary injection in 12 cases (GB injection: 3 cases, PTGBD: 8 cases, ENBD:1 case). The course of the biliary tree was able to be confirmed in all cases that received direct injection into the biliary tract, whereas bile structures were recognizable in only 10 cases (83.3%) with intravenous injection. The postoperative hospital stay was 4.6 (3-9) days, and no postoperative complications (Clavien-Dindo ≧IIIa) were observed. For hepatectomy, a tumor located near the left Glissonian pedicle was resected using a fluorescence image guide. Biliary structures were fluorescent without injury after resecting the tumor. No adverse events due to ICG administration were observed, and the procedure was able to be performed safely. CONCLUSION: ICG fluorescence imaging allows surgeons to visualize the course of the biliary tree in real time during cholecystectomy and hepatectomy. This is considered essential for hepatobiliary surgery to prevent biliary tree injury and ensure safe surgery.

Auto-positive feedback regulation for nicotinic acetylcholine receptors by protein kinase C activation.

BACKGROUND/AIMS: Protein kinase C (PKC) is well-recognized to modify ligand-gated ion channels such as nicotinic ACh (nACh) receptors by phosphorylating the receptors. The aim of the present study was to obtain direct evidence for PKC activation through nACh receptors. METHODS: Two-electrode voltage-clamp was made to Xenopus oocytes expressing wild-type and mutant Torpedo nACh receptors. Western blotting using antibodies against phospho-serine and phospho-threonine was carried out in oocytes expressing Torpedo nACh receptors. In situ PKC activation was monitored in cultured rat skeletal muscle cells expressing nACh receptors. RESULTS: In the Xenopus oocyte expression systems, ACh-evoked whole-cell membrane currents through wild-type Torpedo nACh receptors were depressed by GF109203X, a PKC inhibitor, while currents through mutant receptors lacking PKC phosphorylation sites was not affected. In the Western blot analysis, ACh produced immunoreactive bands against an anti-phospho-serine or an anti-phospho-threonine antibody in oocytes expressing wild-type Torpedo nACh receptors, and those signals were attenuated by alpha-bungarotoxin, an inhibitor of nACh receptors, or GF109203X. In the in situ PKC assay using cultured rat muscle cells that expressed all the mRNAs for muscle nACh receptor subunits such as the alpha, beta, gamma, delta, and e subunit, ACh activated PKC in the presence of atropine, an inhibitor of muscarinic ACh receptors, and the activation was abolished by alpha-bungarotoxin or GF109203X. CONCLUSION: The results of the present study show that ACh activates PKC through nACh receptors and that in turn, activated PKC constantly enhances ACh receptor responses by phosphorylating the receptors. This may represent a new auto-positive feedback regulation for nACh receptors by PKC activation.

An Improved Encapsulation Method for Cryopreserving Hepatocytes for Functional Transplantation Using a Thermo-reversible Gelation Polymer.

BACKGROUND/AIM: Thermo-reversible gelation polymer (TGP) can be converted into a gel state upon warming and liquid upon cooling. The present study aimed to demonstrate a new method for cryopreservation and encapsulation of rat hepatocytes using a TGP and their successful transplantation. MATERIALS AND METHODS: The isolated rat hepatocytes were microencapsulated using TGP, and stored in liquid nitrogen. After cryopreservation, hepatocytes were cultured. Moreover, hepatocytes were transplanted into the spleen without a TGP capsule. RESULTS: The viability of hepatocytes that were cryopreserved in TGP was 71.2±2.3%. The hepatocytes demonstrated adequate survival, maintained their hepatic function in culture, and expressed albumin after transplantation to the rat spleen. CONCLUSION: We demonstrated a cryopreservation method of rat hepatocyte encapsulation using a TGP gel in the hydrogel state which subsequently allowed successful transplantation of unencapsulated hepatocytes in a sol state TGP gel at low temperature.