Effect of Vinyl Acetate, Glass Fibers Contents, and Buffer Space on EVA's Mechanical Property and Shock Absorption Ability.

OBJECTIVES: The aim of the study was to evaluate the mechanical properties and impact absorption capacity of prototype materials comprising ethylene vinyl acetate (EVA) of different hardness reinforced using different amounts of glass fibers (GFs), considering a buffer space. MATERIALS AND METHODS: Six prototype materials were made by adding E-GFs (5 and 10 wt%) to EVA with vinyl acetate (VA) contents of 9.4 wt% ("hard" or HA) and 27.5 wt% ("soft" or SO). Durometer hardness and tensile strength tests were performed to evaluate the mechanical properties of the materials. Moreover, an impact test was conducted using a customized pendulum impact tester to assess the impact absorption capacity (with or without a buffer space) of the specimens. RESULTS: The mechanical properties of the prototypes, namely, durometer hardness, Young's modulus, and tensile strength, were significantly higher in the HA group than in the SO group, regardless of the presence or added amount of GFs. The addition of GFs, particularly in a large amount (10 wt%), significantly increased these values. In terms of the impact absorption capacity, the original hardness of the EVA material, that is, its VA content, had a more substantial effect than the presence or absence of GFs and the added amount of GFs. Interestingly, the HA specimens with the buffer space exhibited significantly higher impact absorption capacities than the SO specimens. Meanwhile, the SO specimens without the buffer space exhibited significantly higher impact absorption capacities than the HA specimens. Moreover, regardless of the sample material and impact distance, the buffer space significantly improved impact absorption. In particular, with the buffer space, the impact absorption capacity increased with the added amount of GFs. CONCLUSION: The basic mechanical properties, including durometer hardness, Young's modulus, and tensile strength, of the EVA prototype were significantly increased by reducing the amount of VA regardless of the presence or added amount of GFs. Adding GFs, particularly in large amounts, significantly increased the values of aforementioned mechanical properties. Impact absorption was significantly affected by the hardness of the original EVA material and enhanced by the addition of the buffer space. The HA specimen had a high shock absorption capacity with the buffer space, and the SO specimen had a high shock absorption capacity without the buffer space. With the buffer space, impact absorption improved with the amount of added GFs.

Head injuries caused by contact with teeth during sports and exercise activities in Japanese schools during the period 2012-2018.

BACKGROUND/AIM: During sports activities, teeth-related contact can cause injury to both ally and opponent players, which can lead to potential infections and aesthetic problems. However, the extent of such injuries remains unclear. This study aimed to clarify the frequency and situation of head injuries caused by teeth (HICBT) occurring under the supervision of schools in Japan. MATERIAL AND METHODS: HICBT records were extracted from the Japan Sport Council data on head injuries occurring reported during the 7-year period from 2012 to 2018 under the supervision of schools in Japan. RESULTS: Of the total 463,527 head injury cases during the study period, 4495 cases (approximately 1%) were HICBT. Of the HICBT cases, 3650 (81.20%) were related to sports and athletic activity. Such injuries were reported to occur most often during basketball with a rate of 57.07% and 50.43%; soccer/futsal was the next most common sport with a rate of 13.38% and 24.01% in junior high school and high school students. Tag games were responsible for a similar number of HICBT cases at 22.73% and 39.03% in kindergartens and elementary school students. CONCLUSIONS: A total of 4495 cases of HICBT were identified, accounting for about 1% of all head injuries under the supervision of schools in Japan during the study period. This result reminds us that our teeth could be the weapon against the players during sports events. HICBTs occurring during basketball and soccer/futsal, in which mouthguards are not mandatory, were conspicuous among junior and senior high school students. Active use of mouthguards in various sports will protect players as well as their teammates and opponents. Sports dentists should encourage the revision of rules, such as mandating the use of mouthguards, in popular sports with a high incidence of HICBT, such as basketball and soccer/futsal.

How to do repeat hepatectomy for remnant liver recurrence using diaphragmatic incision for right liver mobilization.

In addition to difficulties with parenchymal resection reflecting anatomic disorientation arising from rotation of the liver remnant that accompanies regeneration, repeat resections typically involve difficult and protracted lysis of adhesions. We describe our technique for facilitating right liver mobilization even in the presence of severe adhesions. Lysis of dense retroperitoneal adhesions posterior to the right liver can be performed safely by incising the diaphragm to facilitate manipulations to mobilize the right liver.

Improving light-cured intermediate resin for hard and space mouthguard using a glass fiber.

BACKGROUND/AIMS: A light-cured intermediate material is useful for fabricating a hard insert and a buffer space mouthguard (H&SMG). However, it requires improvement in its mechanical properties and shock-absorbing capacity. The aim of this study was to evaluate the mechanical properties of two prototype light-cured intermediate materials reinforced with glass fibers, and the impact absorption capacity and durability of H&SMGs made with the prototype intermediate materials. MATERIALS AND METHODS: Two prototype materials containing long and microlength glass fibers in a light-cured intermediate material, Innerframe LC®, for H&SMG, were fabricated and tested. A three-point bending test was performed for evaluation of the mechanical properties. In addition, a shock absorption test was conducted using a customized pendulum impact testing machine to evaluate the H&SMGs' impact absorption capacity and durability. RESULTS: Long and microlength glass fibers significantly improved flexural modulus and strength. H&SMGs made with these two glass fiber-containing materials had high impact absorption capacity against both low and high impact forces, while the mouthguards made with long glass fiber materials had the best results. CONCLUSION: Long and microlength glass fibers with the prototype materials improved the mechanical properties of Innerframe LC® and the impact absorption capacity and durability of H&SMGs. H&SMGs made with the long glass fiber prototype materials had the best performance.

Jaw-Clenching Intensity Effects on Masseter Oxygen Dynamics and Fatigue: A NIRS Oximetry Study.

The purpose of this study was to clarify the effects of jaw-clenching intensity on masseter muscle oxygen dynamics during clenching and recovery and masseter muscle fatigue using the spatially resolved method of near-infrared spectroscopy. Pulse rate, mean power frequency from electromyography in the masseter and visual analogue scale for masseter fatigue were also examined as related items. The 25% and 50% maximum voluntary contractions were determined using electromyography before the experiment and used as visual feedback on the screen. Twenty-three healthy adult male subjects volunteered for this study. Clenching decreased oxygen and oxygenated haemoglobin, and increased deoxygenated haemoglobin in the masseter muscle. The higher the intensity of clenching, the more prominent the effect. The oxygen dynamics tended to return to normal after clenching, but the change was slower with higher clenching intensity. Pulse rate increased with clenching, and the increment was more prominent with higher clenching intensity. Clenching caused a shift of mean power frequency to a lower range, an increase in subjective fatigue, an early appearance of a breakpoint appearance time and a prolongation of a 1/2 recovery time. All of these effects were more evident with increasing clenching intensity. In conclusion, clenching intensity influenced the oxygen dynamics of the masseter muscle and fatigue state during clenching and recovery. The higher the intensity, the greater the impact.

Modification of ALPPS to avoid ischemia and congestion after stage 1: a case report.

BACKGROUND: Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been advocated for treating advanced liver tumors, but the devascularized ischemic area resulting from liver parenchymal division can become a nidus for sepsis. We present a patient who underwent ALPPS modified to avoid ischemia and congestion after liver partitioning during stage 1. CASE PRESENTATION: ALPPS was carried out for a patient with multiple bilobar liver metastases from rectosigmoid colon cancer. The 2-stage treatment included 3 partial resections within the left lateral section and parenchymal division at the umbilical fissure with right portal vein ligation as stage 1, followed by right trisectionectomy as stage 2. During parenchymal division at the umbilical fissure, Segment 4 portal pedicles and the middle hepatic vein had to be resected at their roots. To safely accomplish this, combined resection of Segment 4 and the drainage area of the middle hepatic vein was performed after parenchymal partition, aiming to avoid ischemia and congestion within the remnant liver. Successful stage 2 hepatectomy followed later. No ischemia or congestion occurred during stage 1 or 2. CONCLUSIONS: During ALPPS, ischemia and congestion after stage 1 must be avoided to reduce morbidity and mortality. The modification described here should reduce likelihood of severe postoperative complications.

Verification of the effectiveness of fucosylated haptoglobin as a pancreatic cancer marker in clinical diagnosis.

BACKGROUND: Fucosylated haptoglobin detected by Pholiota squarrosa lectin (PhoSL) that had specificity for fucose α1-6 was reported as an effective biomarker for several gastrointestinal diseases. The aim of this study was to verify Fucosylated haptoglobin detected by Pholiota squarrosa lectin (PhoSL-HP) as a pancreatic cancer (PC) marker using a new method of PhoSL-ELISA. METHODS: PhoSL-HP in sera from 98 PC patients and 158 non-PC samples including 32 intraductal papillary mucinous neoplasm (IPMN) patients, 21 chronic pancreatitis (CP) patients and 105 non-pancreatic disease controls (NPDC) were measured. We compared sensitivities, specificities and areas under the curves (AUC) of PhoSL-HP, CA19-9 and CEA as single markers. We also evaluated PhoSL-HP as combination marker by comparing AUC of CA19-9 combined with PhoSL-HP or CEA. RESULTS: The sensitivities of PhoSL-HP, CA19-9 and CEA for PC were 58%, 76% and 42%, respectively. Although the specificity of PhoSL-HP for NPDC was inferior to both of CA19-9 and CEA, that for pancreatic diseases was higher than both of CA19-9 and CEA. Combined CA19-9 with PhoSL-HP, the AUC was significantly higher at 0.880 than single use of CA19-9 at 0.825 in case of distinguishing PC from other pancreatic diseases. In contrast, the AUC of CA19-9 was not elevated significantly when combined with CEA. CONCLUSION: PhoSL-HP would be a useful marker for PC and have sufficient complementarity for CA19-9.

Modified Liver Hanging Maneuver for En-bloc Right-sided Hepatectomy Combined with Total Caudate Lobectomy for Colon-Cancer Liver Metastasis and Hepatocellular Carcinoma.

BACKGROUND: A right-sided hepatectomy with total caudate lobectomy is indicated for colorectal-cancer liver metastases (CLM) and hepatocellular carcinomas (HCC) located in the caudate lobe with extension to the right lobe of the liver. Caudate-lobe resection (i.e. segmentectomy 1 according to the Brisbane terminology) is one of the most difficult types of hepatectomy to carry out radically and safely. The deep portion of hepatic transection around the caudate lobe, hepatic veins and inferior vena cava is a critical source of massive bleeding. Prolonged transection can increase blood loss. PATIENTS AND METHODS: We analyzed the outcome of 10 patients who underwent right-sided hepatectomy with caudate lobectomy using a modified liver hanging maneuver (mLHM) in comparison with 16 patients who underwent the operation without mLHM. RESULTS: Blood loss during liver transection and blood loss per unit area of cut surface were significantly less in the mLHM group (p=0.014 and 0.015, respectively). In patients diagnosed pathologically with liver impairment, transection time was significantly shorter in the mLHM group (p=0.038), as were red blood cell transfusion volume (p=0.042) and blood loss (p=0.049) during transection. CONCLUSION: Use of mLHM can potentially improve surgical outcomes by reducing blood loss and transection time, which are especially important for patients with liver impairment.

Blunt penetration technique for treatment of a completely obstructed anastomosis after rectal resection: a case report.

INTRODUCTION: We present a case of completely obstructed anastomosis after rectal resection which was nonsurgically and successfully treated with a blunt penetration technique using a commonly used device for transanal ileus drainage. The technique we used in this case has not been previously reported. CASE PRESENTATION: A 79-year-old Japanese man underwent redo rectal resection for completely separated anastomosis which was caused by anastomotic leakage after a sigmoidectomy performed 3 years previously that was remedied by diverging ileostomy. Immediately after the redo surgery, fluoroscopy showed good passage through the colorectal anastomosis but no anastomotic leakage. However, fluoroscopy and colonoscopy prior to the ileostomy takedown showed complete obstruction of the anastomosis. Unlike usual anastomotic strictures, the lumen between colon oral and rectum anal to the anastomosis was completely discontinued by a membranous structure. Therefore, a conventional balloon dilatation technique was unsuitable for this condition. We applied a blunt penetration technique using a commercially available device designed as a transanal drainage system for obstructing colorectal cancer to restore the continuity between the colon oral and rectum anal to the anastomosis. After restoring the continuity, we performed conventional balloon dilatation for the anastomosis and successfully treated the anastomotic obstruction. Subsequently, the patient underwent ileostomy takedown and is currently doing well 12 months after the ileostomy takedown. CONCLUSIONS: The penetration technique we applied is easy and less stressful to adopt because it does not require usage of materials specialized for other particular purposes. Furthermore, we believe that this technique is superior in safety to other reported methods for this condition even if applied in the wrong direction because this technique does not utilize electrocision or sharp needle puncture.

Small hepatocellular carcinoma with ring calcification: a case report and literature review.

Ring calcification in untreated hepatocellular carcinoma (HCC) is extremely rare, with only 3 previously reported cases in the English-language literature. A case of HCC with ring calcification was reported in this paper. Additionally, 3 previously reported cases of HCC with ring calcification were reviewed. In 3 of these 4 cases (including our case), surgery was performed. Although the size of the ring-calcified lesion ranged from 3.0-3.7 cm in previously reported cases, the size was only 1 cm in ours. The differentiation of the tumor was moderate in the 2 previously reported cases in the histological findings and poor in ours. In spite of their poor differentiation for their sizes, these tumors showed no early enhancement in dynamic computed tomography. All calcified tumors showed a thick fibrous capsule and extensive necrosis histologically. Ring calcification was considered to result from a circulatory disturbance caused by the imbalance between the less abundant arterial blood flow and high inner pressure induced by either the thick fibrous capsule or vigorous proliferation due to the poor differentiation. Ring calcification in untreated HCC may suggest a lower differentiation of the tumor. Even if its size is small, hepatic resection should be performed for any tumor with ring calcification because poor differentiation is considered to be one of the risk factors for recurrence after local ablation therapy, including radio frequency ablation.

Chylous ascites occurring after low anterior resection of the rectum successfully treated with an oral fat-free elemental diet (Elental(®)).

Chylous ascites occurring after abdominal surgery is rare. Despite being potentially critical, there is no definite treatment guideline because of its rarity. Here we present a case of massive chylous ascites occurring after rectal surgery which was successfully treated with an oral fat-free elemental diet (ED). A 67-year-old man underwent low anterior resection with para-aortic lymphadenectomy for advanced rectal cancer. Early postoperative course was uneventful and the patient was discharged from hospital 10 days after surgery; however, after discharge, abdominal distension rapidly developed. Abdominal computed tomography (CT) performed 3 weeks after surgery revealed massive ascites and laboratory findings showed remarkable hypoproteinemia and lymphopenia. Urgent diagnostic paracentesis showed the ascites to be a white milky fluid containing high levels of triglycerides (564 mg/dl), leading to a diagnosis of chyloperitoneum. Daily nutrition of the patient was entirely with a fat-free ED (30 kcal/kg/day of Elental(®), Ajinomoto Pharmaceutical Co. Ltd, Tokyo, Japan). After the initiation of oral Elental(®), abdominal distension, hypoproteinemia, and lymphopenia gradually improved. Abdominal CT performed 7 weeks after surgery showed no ascitic fluid in the abdomen, and thereafter a normal diet was initiated. Since then, no relapse of chyloperitoneum has been proven. As a result, the chylous ascites was successfully treated in the outpatient clinic.

Analysis of gene expression profiles in fatal hepatic failure after hepatectomy in mice.

BACKGROUND: We developed 90%-hepatectomized mice that were the fatal model, and analyzed the gene expression profiles using a complementary DNA (cDNA) microarray to clarify the mechanisms of hepatic failure after excessive hepatectomy. MATERIALS AND METHODS: Ribonucleic acid (RNA)s from the remnant hepatic tissue of 70%- and 90%-hepatectomized mice were labeled with fluorescent dyes, and hybridized to the Riken set of 39,168 full-length enriched mouse cDNA arrays. The gene expression profiles in 90%- and 70%-hepatectomized mice were analyzed by scanning date for fluorescent dye signals. RESULTS: The down-regulated genes in 90%-hepatectomized mice were genes activating extracellular matrix (ECM) remodeling (matrix metalloproteinases, laminins, and integrins), genes related to cytokines (tumor necrosis factor α converting enzyme, and Janus kinase 3) that were related to the priming, genes related to growth factor (heparin-binding epidermal growth factor-like growth factor and others), and genes promoting cell cycle progression (cyclin D1, D2, and E2) that were related to the progression of hepatocytes. The up-regulated genes were genes inhibiting ECM remodeling [plasminogen activator inhibitors (PAIs)]. CONCLUSIONS: Hepatic failure after hepatectomy was characterized by the inhibition of hepatic cell cycle priming and progression both induced by ECM remodeling in liver regeneration. Particularly, the overexpression of PAIs was thought to play the major role in the first step of inhibition of ECM remodeling.

Association between breast cancer risk and the wild-type allele of human ABC transporter ABCC11.

BACKGROUND: International mortality and frequency rates for breast cancer have been associated with the wet type of human earwax. It was recently found that earwax type is determined by a single nucleotide polymorphism (SNP), 538G>A (Gly180Arg), in ABCC11. The G allele determines the wet type of earwax as a Mendelian trait with a dominant phenotype. The present study examined the association between the frequency rate of breast cancer and the frequency of the G allele of ABCC11. PATIENTS AND METHODS: Using blood samples from patients with invasive breast cancer (n = 270) and control volunteers (n = 273), the 538G>A SNP in ABCC11 was genotyped using the SmartAmp method. RESULTS: The frequency of the G allele in breast cancer patients was higher than that in healthy controls. The odds ratio for the genotypes (G/G+G/A) to develop breast cancer was estimated to be 1.63 (p-value = 0.026), suggesting that the G allele in ABCC11 is associated with breast cancer risk. CONCLUSION: This study showed that Japanese women with wet earwax have a higher relative risk of developing breast cancer than those with dry earwax. The ABCC11 SNPs that determine these phenotypes should be further investigated in order to obtain insights into the mechanisms by which breast cancer develops and progresses.

Two-stage treatment of an unusual haemobilia caused by intrahepatic pseudoaneurysm.

A 84-year-old man with a surgical history of subtotal gastrectomy for gastric cancer was transferred to our department because of a disorder of consciousness. Septic shock due to obstructive suppurative cholangitis secondary to choledocholithiasis was diagnosed. Anemia was also present, and upper gastrointestinal tract endoscopy revealed blood emerging from the Papilla of Vater. The cause of the anemia was identified as haemobilia. Angiography showed a small aneurysm over the artery on segment 3 (A3). The cause of the haemobilia was suspected to be the bleeding into the biliary tree from this aneurysm. Because the patient's general condition was poor, minimally invasive therapy was needed. Transcatheter arterial embolization (TAE) was selected initally. Later, lateral sectionectomy was performed in order to remove the aneurysm on A3. No surgical complication occurred and, after surgery, no haemobilia was identified. In conclusion, a two-stage treatment, namely, surgery following TAE, is recommended for patients in a physically poor condition who have haemobilia due to intrahepatic aneurysm.

Pathogenesis in ABO incompatible liver transplantation: a clinicohistological evaluation of four patients.

The aim of this study was to clarify the pathogenesis of antibody-mediated rejection (AMR) of ABO-incompatible liver transplantation (ABO-I-LT). We investigated, within one month of surgery, the clinical courses of 10 patients who received ABO-I-LT. We encountered four cases of AMR, which were classified into two groups according to the stage of the AMR: early (within the first 14 postoperative days [PODs]) or late (after the 14th POD). There were three patients in the early stage, and one patient in the late stage. Three early-stage AMR patients had both hyperbilirubinemia and thrombocytopenia within one month after LDLT, but the one late-stage AMR patient had neither. On liver biopsy, hemorrhagic infiltration was seen more frequently in the early-stage AMR patients than in the patient with late-stage AMR. Plasma exchange combined with a large amount of gamma-globulin bolus infusion therapy was effective in the three early-stage patients, but the late-stage AMR was controlled by antibiotic treatment. This study showed that the early-stage AMR resulted from the antigen-antibody reaction of ABO-blood-group antigens, while the late-stage AMR may have been caused by an infection.

Technique of right hemihepatectomy preserving ventral right anterior section guided by area of hepatic venous drainage.

BACKGROUND: Although the consequences of partial venous outflow interruption have attracted only limited attention in liver surgery, maximal preservation of liver function after hepatic resection requires preservation of circulation in the remnant liver, especially hepatic vein drainage. METHODS: Data from 30 patients undergoing 3-dimensional imaging were analyzed to clarify the relationship between the area of the ventral right anterior section (RAS) and that drained by regional hepatic vein tributaries. The feasibility of our preliminary technique of right hemihepatectomy preserving the ventral RAS also was evaluated. RESULTS: The median estimated volume of the ventral RAS was 230 mL (range, 88-391). The average ratio of this estimated volume of the ventral RAS to total estimated liver volume was 18.0 +/- 4.9%. The median volume of the territory served by middle hepatic vein (MHV) tributaries draining the ventral RAS, expressed as a percentage of the whole volume of the ventral RAS, was 82.5%. Findings in fusion images of portal and hepatic vein territories demonstrated an area of MHV tributaries comparable with the ventral RAS area in 73.3% of all cases. As for the results of right hemihepatectomy with the ventral RAS preserved, no tumor was exposed on transection surfaces, and no recurrence took place within the preserved ventral RAS of the remnant liver. CONCLUSION: Procedures considering the importance of regional venous drainage offer the possibility of reducing the extent of surgery without loss of effectiveness.

Efficacy of repeat hepatic resection for recurrent hepatocellular carcinomas.

BACKGROUND: This study evaluated the efficacy of repeat hepatic resection for recurrent hepatocellular carcinoma (HCC) and the clinicopathological factors influencing overall survival after resection. METHODS: From 1992 to 2005, 231 patients underwent curative hepatic resection for HCC at Yokohama City University, Japan. Of these, 105 patients developed intrahepatic recurrence, and 24 repeat hepatectomies were performed for recurrent HCC. Survival data were analysed, and prognostic factors for repeat hepatic resection were determined. RESULTS: The overall cumulative 1-, 3- and 5-year survival rates and the median survival time of the patients after initial hepatic resection (n= 231) did not differ from those of the patients after repeat hepatic resection (n= 24), with values of 91.3, 70.2 and 49.1%, and 57 months, versus 91.7, 73.1 and 50.9%, and 61.5 months, respectively (P= 0.875). The operative time and blood loss in patients who underwent repeat hepatic resection did not differ from those who underwent primary resection. Multivariate analysis identified portal invasion at the first hepatic resection and a disease-free interval of 1.5 years since the previous surgery.

Validity of hepatic resection of colorectal liver metastases in the elderly (75 years and older).

AIM: To evaluate the validity of surgical therapy for colorectal liver metastases in the elderly patients. PATIENTS AND METHODS: Between 1992 and 2004, 401 patients were diagnosed as having liver metastases from colorectal cancer. These comprised 64 patients aged 75 years or older and 337 patients aged less than 75 years. RESULTS: Two hundred and thirty-two patients (57.9%) underwent potentially curative hepatic resection. Postoperative complications occurred in 29.6% of the older patients and in 23.4% of the younger patients. Mortality was 0% in the older group and 0.5% in the younger group. The overall 5-year survival rates of the older and younger group were 33.2% and 47.9%, respectively (p < 0.01). The proportion of patients who died of other diseases was significantly higher in the older (11.1%) than the younger group (2.0%) (p = 0.04). CONCLUSION: Age cannot be regarded as a medical contraindication for hepatic resection of colorectal liver metastases.

Prostaglandin E1 prevents liver failure after excessive hepatectomy in the rat by up-regulating Cyclin C, Cyclin D1, and Bclxl.

Prostaglandin E1 (PGE1) has wide-ranging effects on cytoprotection and may play a role in preventing liver failure following excessive hepatectomy. We examined the effect of PGE1 on hepatocyte apoptosis and liver regeneration after 95% hepatectomy in a rat model. PGE1 or vehicle was intravenously administered 30 minutes before and during hepatectomy. The extent of hepatocyte injury was evaluated by serum alanine aminotransferase and aspartate aminotransferase levels. To evaluate hepatocyte apoptosis and liver regeneration, terminal deoxynucleotidyl transferase dUTP nick end labeling staining and Ki67 labeling were performed. The expression levels of Bcl-xL, Bcl-2, Bax, Cyclin C, Cyclin D1, Cyclin E, p21, transforming growth factor-beta, plasminogen activator inhibitor-1, and glyceraldehyde-2-phosphate dehydrogenase mRNA were also examined by reverse transcription-polymerase chain reaction. Survival was improved in the PGE1 group (26.6%), whereas all rats in the vehicle group died within 60 hours. PGE1 significantly suppressed the release of alanine aminotransferase and aspartate aminotransferase at 12 hours postoperatively. Pretreatment with PGE1 significantly increased the Ki67-positive cell count and decreased the terminal deoxynucleotidyl transferase dUTP nick end labeling positive cell count after hepatectomy, and also significantly increased the expression levels of Bcl-xL, Cyclin C, and Cyclin D1. Our results suggest that pretreatment with PGE1 may increase survival following hepatectomy by salvaging the remaining liver tissue, which it does by inhibiting apoptosis and stimulating hepatocyte proliferation.

Gene expression during liver regeneration after partial hepatectomy in mice lacking type 1 tumor necrosis factor receptor.

BACKGROUND: To investigate the function of tumor necrosis factor-alpha (TNF-alpha) during hepatocyte proliferation, we studied liver regeneration following partial hepatectomy in mice lacking type 1 TNF receptor (TNFR-1). MATERIALS AND METHODS: TNFR-1 knockout (KO) and wild-type mice were subjected to partial (two-thirds) hepatectomy. Liver regeneration was evaluated by assessing liver weights and Ki67 immunohistochemistry. Riken complementary DNA microarray analysis was performed for liver samples from mice undergoing partial hepatectomy to better compare different mouse partial hepatectomy models (TNFR-1 KO mice, KO group; and wild-type mice, W group). RESULTS: Liver weight was regained after 14 days in the KO group, and after 7 days in the W group. Genes including lipopolysaccharide, toll-like receptor 4 precursor, mitogen-activated protein kinase kinase kinase 4, mitogen-activated protein kinase kinase kinase kinase 4, and mitogen-activated protein kinase 8-interacting protein were up-regulated in the KO group. As for the cell-cycle-regulated genes, the levels of cyclin D1, nuclear factor-kappa B light chain, and TNF receptor super family membrane 1a were down-regulated in the KO group. Microarray analysis showed decreased activities of the hexokinase- and phospho-fructokinase-related glycolytic pathways in the KO group. CONCLUSIONS: These results contribute to the better understanding of the mechanisms of liver regeneration after partial hepatectomy in TNFR-1 KO mice.