Segment 4 Research Articles

Localization of an Alternative Ion Permeation Pathway in TRPM3

Transient receptor potential (TRP) channels are cationic channels that are involved in a broad array of functions, including homeostasis, motility and sensory functions such as taste transduction, nociception, and temperature sensing. In general, the activation of these channels leads to the opening of their central channel pore resulting in a cationic influx and a subsequent depolarization of the cell. TRP melastatin 3 (TRPM3) is a member of the melastatin family of TRP channels and was shown to be expressed in sensory neurons where it acts as noxious heat sensor and nociceptor. Activation of TRPM3 results typically in an outward-rectifying current-voltage (I-V) curve due to the opening of the central pore of the channel. Recently, it was shown that certain agonists can induce the opening of an alternative ion permeation pathway next to the central pore, resulting in outward- and inward-rectifying currents. Here we use mutagenesis studies to localize the alternative pore of TRPM3. Our data suggest the location of the alternative pore in the voltage-sensing domain (VSD) of the channel and more specifically in proximity to transmembrane segment 4 (S4). We show three residues (W982, D988 and G991) that seem to be involved in the shaping of the alternative ion permeation pathway. The results obtained in this study are in line with the location of other non-canonical pores described in mutated voltage-gated K+-, Na+- and Ca2+-channels and propose the potential occurrence of non-canonical pores in other ion channels that are lacking the typical gating charges found in voltage-gated channels.

Molecular variation and expansion of a rice black-streaked dwarf virus population based on analysis of segment 1 in Jining, China.

To analyze the variation in rice black-streaked dwarf virus (RBSDV) in an area with high incidence of maize rough dwarf disease (MRDD), the RBSDV S1 segment in a collection of 100 maize isolates (sample population A100) from Jining, Shandong Province, was sequenced. An additional 21 maize and rice isolates (subpopulation B21) that were sampled from nine other geographic locations in China in 2012 and 2013 were used as a control. A total of 914 nucleotide mutations, including 239 singleton variable and 675 parsimony-informative sites were detected among the segment 1 (S1) sequences from A100. A total of 614 nucleotide mutation sites including 164 singleton variable and 450 parsimony-informative sites were detected among the S1 sequences from B21, while 97.55% of the parsimony-informative sites from B21 were also detected in A100. The nucleotide sequence diversities of A100 (π=0.0479) and B21 (π=0.0396) were significantly different (P = 0.0002) but showed similar trends. Phylogenetic analysis showed that the 121 RBSDV isolates could be classified into two groups based on their S1 sequences, independent of subpopulation, with a combination of host species and locations. A100 and B21 were under the same level of negative and purifying selection, with Ka/Ks ratios of 0.0337 and 0.0369, respectively. The combined RBSDV population, including 121 isolates, was expanding, with negative values for Tajima's D, Fu and Li's D, and Fu and Li's F in both A100 and B21, except Tajima's D in A100. Based on S1, the RBSDV population in China has long-term phytogeographic stability, and there do not appear to be any newly-emerging strains.

Improving graft survival by understanding the mechanism of segment 4 complications after split liver transplantation.

This study was designed to assess the actual mechanism of segment 4 (S4)-related complications after split liver transplantation (SLT) and their impact on graft and overall survival with reference to those of left lateral sectionectomy for pediatric living donor liver transplantation (LLSLD). Clinical data from 53 SLT recipients and 62 LLSLD patients were assessed to determine the mechanism of S4-related complications. The postoperative parameters of SLT and their impact on graft and overall survival were also evaluated. Although two biliary leakages were noted (3.2%), no necrosis of S4 developed after LLSLD. S4-related complications were seen in 15 (28.3%) patients after SLT. Radiological volumetry of S4 and the ischemic area after SLT showed no significant difference between those with and without S4-related complications. There were no significant differences between the patients with and without S4-related complications regarding both overall and graft survival rates. Significant better overall and graft survival rates were observed in patients treated during the later period. S4-related complications after SLT are totally independent of the S4 volume, and biliary leakage is inherently an actual mechanism. Adequate intervention with early identification leads to better graft and overall survival, which validates SLT as a treatment option.

Reconstitution of the RNA-dependent RNA polymerase activity of Antheraea mylitta cypovirus in vitro using separately expressed different functional domains of the enzyme.

Antheraea mylitta cytoplasmic polyhedrosis virus is a segmented dsRNA virus of the family Reoviridae. Segment 2 (S2)-encoded RNA-dependent RNA polymerase (RdRp) helps the virus to propagate its genome in the host cell of the silkworm, Antheraea mylitta. Cloning, expression, purification and functional analysis of individual domains of RdRp have demonstrated that the purified domains interact in vitro. The central polymerase domain (PD) shows nucleotide binding properties, but neither the N-terminal domain (NTD) nor the C-terminal domain (CTD). Isolated PD does not exhibit RdRp activity but this activity can be reconstituted when all three domains are included in the reaction mixture. Molecular dynamics simulation suggests that the isolated PD has increased internal motions in comparison to when it is associated with the NTD and CTD. The motions of the separated PD may lead to the formation of a less accessible RNA template-binding channel and, thus, impair RdRp activity.

Cryo-electron microscopy structure of the TRPV2 ion channel.

Transient receptor potential vanilloid (TRPV) cation channels are polymodal sensors involved in a variety of physiological processes. TRPV2, a member of the TRPV family, is regulated by temperature, by ligands, such as probenecid and cannabinoids, and by lipids. TRPV2 has been implicated in many biological functions, including somatosensation, osmosensation and innate immunity. Here we present the atomic model of rabbit TRPV2 in its putative desensitized state, as determined by cryo-EM at a nominal resolution of ~4 Å. In the TRPV2 structure, the transmembrane segment 6 (S6), which is involved in gate opening, adopts a conformation different from the one observed in TRPV1. Structural comparisons of TRPV1 and TRPV2 indicate that a rotation of the ankyrin-repeat domain is coupled to pore opening via the TRP domain, and this pore opening can be modulated by rearrangements in the secondary structure of S6.

Total anatomical laparoscopic liver resection of segment 4 (S4), extended S4, and subsegments S4a and S4b for hepatocellular carcinoma.

When a tumor is located in segment 4 (S4), it is preferable to perform only limited resection of S4, even in laparoscopic surgery. Here we describe anatomical laparoscopic S4, subdivision of S4 (S4a and S4b), and extended S4 segmentectomy for hepatocellular carcinoma (HCC), using the Glissonian pedicle transection method for each, and evaluate the feasibility of laparoscopic liver resection (LLR) for tumors located in S4. Among 417 patients who underwent LLR for malignant tumors between March 2003 and February 2014, we performed retrospective analysis of the clinical and perioperative outcomes of 10 patients who underwent anatomical liver resection for tumors located in the S4 area of the liver. Total laparoscopic anatomic liver resection (S4, extended S4, and S4a and S4b segmentectomies) were performed in 10 patients. There was no open conversion or postoperative mortality. The mean operation time was 316.5 minutes (range, 175-460 minutes), and mean estimated blood loss was 592 mL (range, 100-1600 mL). An intraoperative transfusion was necessary in 2 (20%) of the 10 patients. All patients had negative resection margins. Three patients (30%) had postoperative complications (intraabdominal fluid collection). The mean postoperative hospital stay was 7.7 days (range, 3-13 days). The median follow-up period was 18 months. Intrahepatic recurrence occurred in 2 (20%) of the 10 patients, which was managed by radiofrequency ablation with transarterial chemoembolization in 1 patient and by transarterial chemoembolization alone in the other patient. Total laparoscopic anatomical S4, extended S4, or S4a or S4b segmentectomy is a feasible procedure for HCC. The Glissonian pedicle transection method is an effective technique for rapid and safe control and subdivision of the S4 pedicle that facilitates anatomical laparoscopic S4, extended S4, and S4a and S4b segmentectomy.

Hepatic angiomyolipoma: differential diagnosis from other liver tumors in a special reference to vascular imaging - importance of early drainage vein.

A 51-year-old female had been diagnosed with a hemangioma in the hepatic segment 6 (S6). After a 6-year follow-up, enlargement of the tumor was detected. The tumor was clearly enhanced in the arterial phase, and the enhancement remained in the portal phase on computed tomography (CT). Although the primary differential diagnosis on CT was hepatocellular carcinoma (HCC), we worried about the possibility of other vessel system tumors because the tumor remained to be enhanced at the portal phase for HCC and all tumor markers of HCC were negative. We performed angiography to determine the tumor nature and to seek other tumors. Angiography showed tumor stain at the hepatic S6 with an early obvious drainage vein from the tumor flowing through the right hepatic vein into the inferior vena cava. In addition to tumor stain and the drainage vein, there were many small poolings of contrast medium in the whole liver, which were suspected as dilatation of the hepatic peripheral artery. We suspected the tumor as a benign tumor such as hepatocellular adenoma or focal nodular hyperplasia, but the possibility of HCC could not be ruled out. Hepatic posterior sectionectomy was done to completely remove the drainage vein with the tumor. Intraoperative histological examination revealed the tumor as not malignant and not HCC. Later, immunohistochemical analysis uncovered that the tumor had high expression of HMB-45 and, therefore, the final diagnosis was angiomyolipoma. We think that detecting an early drainage vein from the tumor would be a key point for diagnosing hepatic angiomyolipoma.

Selection of living donor liver grafts for patients weighing 6kg or less.

In the field of pediatric living donor liver transplantation (LDLT), physicians sometimes must reduce the volume of left lateral segment (LLS) grafts to prevent large-for-size syndrome. There are 2 established methods for decreasing the size of an LLS graft: the use of a segment 2 (S2) monosegment graft and the use of a reduced LLS graft. However, no procedure for selecting the proper graft type has been established. In this study, we conducted a retrospective investigation of LDLT and examined the strategy of graft selection for patients weighing ≤6 kg. LDLT was conducted 225 times between May 2001 and December 2012, and 15 of the procedures were performed in patients weighing ≤6 kg. We selected S2 monosegment grafts and reduced LLS grafts if the preoperative computed tomography (CT)-volumetry value of the LLS graft was >5% and 4% to 5% of the graft/recipient weight ratio, respectively. We used LLS grafts in 7 recipients, S2 monosegment grafts in 4 recipients, reduced S2 monosegment grafts in 3 recipients, and a reduced LLS graft in 1 recipient. The reduction rate of S2 monosegment grafts for use as LLS grafts was 48.3%. The overall recipient and graft survival rates were both 93.3%, and 1 patient died of a brain hemorrhage. Major surgical complications included hepatic artery thrombosis in 2 recipients, bilioenteric anastomotic strictures in 2 recipients, and portal vein thrombosis in 1 recipient. In conclusion, our graft selection strategy based on preoperative CT-volumetry is highly useful in patients weighing ≤6 kg. S2 monosegment grafts are effective and safe in very small infants particularly neonates.

Segment 4 and the left lateral segment regeneration pattern after resection of the middle hepatic vein in a living donor right hepatectomy

BackgroundInclusion of the middle hepatic vein (MHV) with a right hepatectomy (RH) in live donor liver transplantation improves venous drainage of the anterior sector of the graft. Its long-term effects on donor left liver (LL) regeneration are not well described. MethodsDonors who underwent RH with MHV (MHV+, n = 12) were compared with donors who underwent RH with preservation of the MHV (MHV–, n = 24). Peri-operative complications and volume of the entire liver and individual segments were evaluated at 1 year post-donation. ResultsThere was a trend towards a higher complication rate in the MHV+ group (41% versus 25%), without reaching statistical significance (P = 0.3). Males, high body mass index (BMI) and a smaller residual liver volume (RLV) were predictors for greater LL regeneration. MHV+ donors had impaired regeneration of segment 4 (S4) at 1 year, and compensatory greater left lateral segment regeneration. The absence of venous drainage of S4 (V4) to left hepatic vein (LHV) was a predictor of impaired S4 regeneration. ConclusionsRegeneration of S4 is impaired in MHV+ donors. Caution should be taken when considering MHV removal on donors with dominant S4, especially on those with potential increased demand for liver regeneration, such as males, higher BMI and a smaller RLV.

Heterogeneous living donor hepatic fat distribution on MRI chemical shift imaging.

PurposeWe evaluated the heterogeneity of steatosis in living donor livers to determine its regional differences.MethodsBetween June 2011 and February 2012, 81 liver donors were selected. Fat fraction was estimated using magnetic resonance triple-echo chemical shifting gradient imaging in 13 different regions: segment 1 (S1), S2, S3, and each peripheral and deep region of S4, S5, S6, S7, and S8.ResultsThere were differences (range, 3.2%-5.3%) in fat fractions between each peripheral and deep region of S4, S6, S7, and S8 (P < 0.001, P = 0.004, P < 0.001, and P = 0.006). Fat deposit amount in S1, S2, S3 and deep regions of S4-S8 were significantly different from one another (F [4.003, 58.032] = 8.684, P < 0.001), while there were no differences among the peripheral regions of S4-S8 (F [2.9, 5.3] = 1.3, P = 0.272) by repeated measure analysis of variance method. And regional differences of the amount of fat deposit in the whole liver increased as a peripheral fat fraction of S5 increased (R2 = 0.428, P < 0.001).ConclusionMultifocal fat measurements for the whole liver are needed because a small regional evaluation might not represent the remaining liver completely, especially in patients with severe hepatic steatosis.

Structural insight into the transmembrane segments 3 and 4 of the hERG potassium channel.

The hERG (human ether-a-go-go related gene) potassium channel is a voltage-gated potassium channel containing an N-terminal domain, a voltage-sensor domain, a pore domain and a C-terminal domain. The transmembrane segment 4 (S4) is important for sensing changes of membrane potentials through positively charge residues. A construct containing partial S2-S3 linker, S3, S4 and the S4-S5 linker of the hERG channel was purified into detergent micelles. This construct exhibits good quality NMR spectrum when it was purified in lyso-myristoyl phosphatidylglycerol (LMPG) micelles. Structural study showed that S3 contains two short helices with a negatively charged surface. The S4 and S4-S5 linker adopt helical structures. The six positively charged residues in S4 localize at different sides, suggesting that they may have different functions in channel gating. Relaxation studies indicated that S3 is more flexible than S4. The boundaries of S3-S4 and S4-S4-S5 linker were identified. Our results provided structural information of the S3 and S4, which will be helpful to understand their roles in channel gating.

Structural constraints in the packaging of bluetongue virus genomic segments.

The mechanism used by bluetongue virus (BTV) to ensure the sorting and packaging of its 10 genomic segments is still poorly understood. In this study, we investigated the packaging constraints for two BTV genomic segments from two different serotypes. Segment 4 (S4) of BTV serotype 9 was mutated sequentially and packaging of mutant ssRNAs was investigated by two newly developed RNA packaging assay systems, one in vivo and the other in vitro. Modelling of the mutated ssRNA followed by biochemical data analysis suggested that a conformational motif formed by interaction of the 5′ and 3′ ends of the molecule was necessary and sufficient for packaging. A similar structural signal was also identified in S8 of BTV serotype 1. Furthermore, the same conformational analysis of secondary structures for positive-sense ssRNAs was used to generate a chimeric segment that maintained the putative packaging motif but contained unrelated internal sequences. This chimeric segment was packaged successfully, confirming that the motif identified directs the correct packaging of the segment.

Conservative hepatectomy for tumors involving the middle hepatic vein and segment 1: the liver tunnel.

For lesions invading the middle hepatic vein (MHV) at caval confluence (CC) the mini-mesohepatectomy(MMH) was proposed.1 If the lesion is extended to the paracaval portion of segment 1(S1) in contact or invading the MHV a new procedure is proposed. Case-1: mass forming cholangiocarcinoma (MFCCC) 4cm in size invading the MHV and in contact with right (RHV) and left hepatic vein (LHV) at the CC. In Case-2, two colorectal liver metastases (CLM) both 2cm in size occupied S1 (T1) and S8 (T2): T1 was located between RHV and the inferior vena cava (IVC), T2 was in contact with MHV at CC. According to tumor-vessel intraoperative-ultrasound classification2 and color-flow analysis3 parenchyma-sparing procedure was performed. In Case-1 a communicating vein (CV) between RHV and MHV was detected at color-flow-IOUS. Contacts between MFCCC with RHV and LHV were confirmed at IOUS as detachable. In Case-2 contact between T1 with MHV was confirmed at IOUS as detachable. Liver-tunnel with IVC and main portal vein bifurcation exposure was performed resecting the MHV in Case-1 and preserving it in Case-2. Both patients had ad an uneventful postoperative course and were discharged on the 8th postoperative day. For tumors involving S1, S4s and/or S8 and infiltrating or in contact with the MHV at the CC, can be removed in a conservative manner by means of the herein described ''Liver Tunnel'' approach. The latter introduces a further step in favour of parenchyma-sparing policy for centrally located lesions with complex tumor-vessel relationship.

Genome segment 5 of Antheraea mylitta cytoplasmic polyhedrosis virus encodes a bona fide guanylyltransferase.

BackgroundAntheraea mylitta cytoplasmic polyhedrosis virus (AmCPV), a cypovirus of Reoviridae family, infects non mulberry Indian silk worm, Antheraea mylitta, and contains eleven segmented double stranded RNA in its genome (S1-S11). Some of its genome segments (S1-S3, and S6-S11) have been previously characterized but genome segment encoding the viral guanylyltransferase which helps in RNA capping has not been characterized.ResultsIn this study genome segment 5 (S5) of AmCPV was converted to cDNA, cloned and sequenced. S5 consisted of 2180 nucleotides, with one long ORF of 1818 nucleotides and could encode a protein of 606 amino acids with molecular mass of ~65 kDa (p65). Bioinformatics analysis showed presence of KLRS and HxnH motifs as observed in some other reoviral guanylyltransferase and suggests that S5 may encodes viral guanylyltransferase. The ORF of S5 was expressed in E. coli as 65 kDa his tagged fusion protein, purified through Ni-NTA chromatography and polyclonal antibody was raised. Immunoblot analysis of virion particles with the purified antibody showed specific immunoreactive band and suggests p65 as a viral structural protein. Functional analysis showed that recombinant p65 possesses guanylyltransferase activity, and transfers GMP moiety to the 5' diphosphate (A/G) ended viral RNA after the formation of p65-GMP complex for capping. Kinetic analysis showed Km of this enzyme for GTP and RNA was 34.24 uM and 98.35 nM, respectively. Site directed mutagenesis at K21A in KLRS motif, and H93A or H105A in HxnH motif completely abolished the autoguanylylation activity and indicates importance of these residues at these sites. Thermodynamic analysis showed p65-GTP interaction was primarily driven by enthalpy (ΔH = -399.1 ± 4.1 kJ/mol) whereas the p65-RNA interaction by favorable entropy (0.043 ± 0.0049 kJ/ mol).ConclusionViral capping enzymes play a critical role in the post transcriptional or post replication modification in case of RNA virus. Our results of cloning, sequencing and functional analysis of AmCPV S5 indicates that S5 encoded p65 through its guanylyltransferase activity can transfer guanine residue to the 5' end of viral RNA for capping. Further studies will help to understand complete capping process of cypoviral RNA during viral replication within the viral capsid.

The VP2 protein of grass carp reovirus (GCRV) expressed in a baculovirus exhibits RNA polymerase activity

The double-shelled grass carp reovirus (GCRV) is capable of endogenous RNA transcription and processing. Genome sequence analysis has revealed that the protein VP2, encoded by gene segment 2 (S2), is the putative RNA-dependent RNA polymerase (RdRp). In previous work, we have ex-pressed the functional region of VP2 that is associated with RNA polymerase activity (denoted as rVP2(390-900)) in E. coli and have prepared a polyclonal antibody against VP2. To characterize the GCRV RNA polymerase, a recombinant full-length VP2 (rVP2) was first constructed and expressed in a baculovirus system, as a fusion protein with an attached His-tag. Immunofluorescence (IF) assays, together with immunoblot (IB) analyses from both expressed cell extracts and purified Histagged rVP2, showed that rVP2 was successfully expressed in Sf9 cells. Further characterization of the replicase activity showed that purified rVP2 and GCRV particles exhibited poly(C)-dependent poly(G) polymerase activity. The RNA enzymatic activity required the divalent cation Mg(2+), and was optimal at 28 °C. The results provide a foundation for further studies on the RNA polymerases of aquareoviruses during viral transcription and replication.

Successful repeated resections of metachronous liver metastases from an early α-fetoprotein-producing gastric cancer: report of a case

We present a case involving successfully repeated resection of metachronous liver metastases from an early alpha-fetoprotein (AFP)-producing gastric cancer (APGC). A 76-year-old male initially underwent laparoscopy-assisted distal gastrectomy (LADG) for early APGC in September 2010. Five months after the LADG, the serum AFP increased to 1871 ng/ml, and multiple liver metastases were detected in Segment 1 (S1), S6, and S8 using computed tomography (CT) and magnetic resonance imaging (MRI). Percutaneous biopsy specimens from the liver tumor revealed hepatoid adenocarcinoma that stained positive for AFP. A partial S1 and S8 hepatectomy and S6 segmentectomy were performed in March 2011. The AFP level decreased to 5 ng/ml within 2 months of the hepatectomy, but increased again to 25 ng/ml 10 months later. CT and MRI revealed a small tumor in S2, and he underwent partial resection of S2 in February 2012. Pathological and immunohistochemical analyses also showed hepatoid adenocarcinoma that stained positive for AFP. His serum AFP level returned to normal, but increased again to 125 ng/ml 11 months later. As CT and MRI showed a tumor in S3, lateral segmentectomy was performed in February 2013. His serum AFP level decreased again to 3 ng/ml, and there has been no evidence of further metastasis in the 6 months since the third hepatectomy. We report this case to show that repeated surgical resection of metachronous liver metastasis from early APGC is feasible and might prolong survival.

Segment 4 architecture and proposed parenchyma-wise technique for Ex vivo graft procurement and implantation

A parenchyma-wise technique for the ex vivo procurement of segment 4 (S4) grafts, based on the detailed architecture of the segment, is proposed. Eighteen normal, fresh livers from adult cadavers were injected differentially with colored latex; dissection casts were prepared; and the intricate architecture of S4 was studied. The portal vein elements of the sheath forming most of the inferior part of S4 (S4b) and the superficial major fraction of its superior part (S4a) arose constantly from the medial aspect of the umbilical part of the left portal vein branch. The arterial elements arose constantly from a branch, whose diameter ranged from 2.00 to 3.35 mm (mean = 2.61 ± 0.54 mm) and whose length ranged from 15.15 to 45.65 mm (mean = 27.98 ± 12.13 mm). The biliary elements coalesced as a single duct at the corner, which was formed from the umbilical and transverse parts of the left portal vein branch; the duct's diameter ranged from 2.90 to 6.85 mm (mean = 3.90 ± 1.34 mm). Theoretically, this parenchymal mass-S4b and the superficial fraction of S4a-could be procured for implantation in an infant, and the rest of the liver could be split for an adult and a child. The portal vein branches of the graft would be procured with a patch from the medial aspect of the donor's umbilical portion of the left portal vein branch. This umbilical portion would be reconstructed with a patch from the donor's round ligament. The recipient's portal vein would be reconstructed through the fashioning of a conduit anastomosed with the graft's venous patch.

Pure Laparoscopic Subsegmentectomy of the Liver Using a Puncture Method for the Target Portal Branch Under Percutaneous Ultrasound With Artificial Ascites

It is important to minimize surgical invasiveness in the therapy of patients with hepatocellular carcinoma (HCC) and, consequently, laparoscopic hepatic resection is widely performed. However, most anatomic resections, except left lateral sectionectomy, are still difficult technically and, as an alternative approach, laparoscopy-assisted procedures also have been introduced because of the safety and curative success of the operation. Herein, we describe pure laparoscopic subsegmentectomy of the liver using puncture of the portal branch under percutaneous ultrasound (US) with artificial ascites. Pure laparoscopic subsegmentectomy of segment 6 (S6) was planned for a patient with HCC of S6 of the liver. The identification of the segment was performed by dye injection under percutaneous US guidance with artificial ascites. The procedure was completed successfully in a minimally invasive manner with an operative time of 260 minutes and with intraoperative blood loss of 10 mL. The difference between the size of the resected specimen and that estimated by 3-dimensional computed tomography was very small. The postoperative course was uneventful and the patient was discharged 10 days after surgery. Pure laparoscopic subsegmentectomy for HCC with a conventional puncture technique under percutaneous US with artificial ascites is considered to be a useful procedure featuring both low invasiveness and curative success.

Application of Hepatic Segmental Staining in Anatomic S8 Segmentectomy Under Intra-Operative Ultrasonography

Objective The purpose of this study was to investigate the clinical value of hepatic segmental staining under intra-operative ultrasonography guidance in anatomic segment 8 (S8) segmentectomy. Method This was a retrospective study of 31 patients with hepatocellular carcinoma (HCC) whose lesions were located in S8. Under intra-operative ultrasonography guidance, the hepatic portal vein branch of S8 was dyed and then the resection line was marked with an electric knife on the stained area of the liver surface, in preparation for the anatomic S8 segmentectomy. The liver section exposed the right hepatic vein, the middle hepatic vein trunk side wall and the hepatic pedicle of S8. Results The average operation time of 31 cases of anatomic S8 segmentectomy was (230±76) min, the average surgical blood loss was (305±235) ml, the incidence of post-operative complications was 26% (8/31), average post-operative hospitalization time was (13±3) d, with a 1-year recurrence rate of 19% (6/31) and a 1-year survival rate of 94% (29/31). Conclusion Under the guidance of intra-operative ultrasonography, hepatic segmental staining can improve the precision of an anatomic S8 segmentectomy, maximally reducing the post-operative complications and improving the safety of liver resection.

Estimation of the Congestion Area Volume in Potential Living Donor Remnant Livers

BackgroundLiving donor liver transplantation is widely performed in adult patients. One of the problems in this setting is a small-for-size graft, which results in dysfunction and poor prognosis of a transplantation. A right liver graft was devised to overcome this problem; furthermore, inclusion of the middle hepatic vein (MHV) has been suggested to greatly improve recipient outcomes. However, extended right hepatectomy involves a surgical risk for the living donor in terms of congestion of the left paramedian sector. The volume of the venoocclusive region of a living donor liver possibly varies depending on the collateral patterns of veins draining the cranial part of segment 4 (S4). Patients and MethodsWe were analyzed the normal livers of 50 patients who underwent triphasic contrast-enhanced multidetector row computed tomography during preoperative and postoperative examinations. The patient pathologies consisted of gastric cancer (n = 25), colon cancer (n = 1), or renal cancer (n = 24). We calculated the volume of the entire liver as well as those of the right graft and left remnant lobes for comparison with the drainage volume of each hepatic vein and its branches. ResultsOn the basis of the anatomic venous drainage of the cranial part of S4 (V4sup), we classified hepatic veins as group A (n = 31), the V4sup joined the left hepatic vein or the MHV distal to the vein draining S8 area (MV8), or group B (n = 19), V4sup joined the MHV proximal to MV8. The mean volume of the congested area was 6.9% in group A and 15.9% in group B. The venoocclusive areas in the remnant livers were estimated to be larger in group B (P < .001). ConclusionThe collateral pattern of V4sup and MV8 as well as preoperative volumetric analysis are important for graft selection to decide the line of transection.