Major hepatectomy with combined vascular resection for perihilar cholangiocarcinoma

Background

Hepatectomy with vascular resection (VR) for perihilar cholangiocarcinoma (PHCC) is a challenging procedure. However, only a few reports on this procedure have been published and its clinical significance has not been fully evaluated.

Methods

Patients undergoing surgical resection for PHCC from 2002–2017 were studied. The surgical outcomes of VR and non-VR groups were compared.

Results

Some 238 patients were included. VR was performed in 85 patients. The resected vessels were hepatic artery alone (31 patients), portal vein alone (37 patients) or both (17 patients). The morbidity rates were almost the same in the VR (49.4 per cent) and non-VR (43.8 per cent) groups (P = 0.404). The mortality rates of VR (3.5 per cent) and non-VR (3.3 per cent) were also comparable (P > 0.999). The median survival time (MST) was 45 months in the non-VR group and 36 months in VR group (P = 0.124). Among patients in whom tumour involvement was suspected on preoperative imaging and whose carbohydrate antigen 19-9 (CA19-9) value was 37 U/ml or less, MST in the VR group was significantly longer than that in the non-VR group (50 versus 34 months, P = 0.017). In contrast, when the CA19-9 value was greater than 37 U/ml, MST of the VR and non-VR groups was comparable (28 versus 29 months, P = 0.520).

Conclusion

Hepatectomy with VR for PHCC can be performed in a highly specialized hepatobiliary centre with equivalent short- and long-term outcomes to hepatectomy without VR.

Utility of remnant liver volume for predicting posthepatectomy liver failure after hepatectomy with extrahepatic bile duct resection

BACKGROUND

Hepatectomy with extrahepatic bile duct resection is associated with a high risk of posthepatectomy liver failure (PHLF). However, the utility of the remnant liver volume (RLV) in cholangiocarcinoma has not been studied intensively.

METHODS

Patients who underwent major hepatectomy with extrahepatic bile duct resection between 2002 and 2018 were reviewed. The RLV was divided by body surface area (BSA) to normalize individual physical differences. Risk factors for clinically relevant PHLF were evaluated with special reference to the RLV/BSA.

RESULTS

A total of 289 patients were included. The optimal cut-off value for RLV/BSA was determined to be 300 ml/m2. Thirty-two patients (11.1 per cent) developed PHLF. PHLF was more frequent in patients with an RLV/BSA below 300 ml/m2 than in those with a value of 300 ml/m2 or greater: 19 of 87 (22 per cent) versus 13 of 202 (6.4 per cent) (P < 0.001). In multivariable analysis, RLV/BSA below 300 ml/m2 (P = 0.013), future liver remnant plasma clearance rate of indocyanine green less than 0.075 (P = 0.031), and serum albumin level below 3.5 g/dl (P = 0.015) were identified as independent risk factors for PHLF. Based on these risk factors, patients were classified into three subgroups with low (no factors), moderate (1-2 factors), and high (3 factors) risk of PHLF, with PHLF rates of 1.8, 14.8 and 63 per cent respectively (P < 0.001).

CONCLUSION

An RLV/BSA of 300 ml/m2 is a simple predictor of PHLF in patients undergoing hepatectomy with extrahepatic bile duct resection.

Prognostic role of the length of tumour-vein contact at the portal-superior mesenteric vein in patients having surgery for pancreatic cancer

BACKGROUND

The length of tumour-vein contact between the portal-superior mesenteric vein (PV/SMV) and pancreatic head cancer, and its relationship to prognosis in patients undergoing pancreatic surgery, remains controversial.

METHODS

Patients diagnosed with pancreatic head cancer who were eligible for pancreatoduodenectomy between October 2002 and December 2016 were analysed. The PV/SMV contact was assessed retrospectively on CT. Using the minimum P value approach based on overall survival after surgery, the optimal cut-off value for tumour-vein contact length was identified.

RESULTS

Among 491 patients included, 462 underwent pancreatoduodenectomy for pancreatic head cancer. PV/SMV contact with the tumour was detected on preoperative CT in 248 patients (53·7 per cent). Overall survival of patients with PV/SMV contact exceeding 20 mm was significantly worse than that of patients with a contact length of 20 mm or less (median survival time (MST) 23·3 versus 39·3 months; P = 0·012). Multivariable analysis identified PV/SMV contact longer than 20 mm as an independent predictor of poor survival, whereas PV/SMV contact greater than 180° was not a predictive factor. Among patients with a PV/SMV contact length exceeding 20 mm on pretreatment CT, those receiving neoadjuvant therapy had significantly better overall survival than patients who had upfront surgery (MST not reached versus 21·6 months; P = 0·002).

CONCLUSION

The length of PV/SMV contact predicts survival, and may be used to suggest a role for neoadjuvant therapy to improve prognosis.

Primary Structure of a Base Non-specific and Adenylic Acid Preferential Ribonuclease from the Fruit Bodies ofLentinus edodes

The complete primary structure of a base non-specific and adenylic acid preferential RNase (RNase Le2) from the fruit bodies of Lentinus edodes was analyzed. The sequence was mostly determined by analysis of the peptides generated by V8 protease digestion and BrCN cleavage (including alpha-chymotryptic, and V8 protease digest of BrCN fragments). It consists of 239 amino acid residues. The molecular weight is 25831. The location of 10 half cystine residues were almost superimposable on those of known fungal RNases of the RNase T2 family. The sequence homologies between RNase Le2 and four known fungal RNases of the RNase T2 family, RNase T2, RNase M, RNase Trv, and RNase Rh, are 102, 103, 109, and 74, respectively. The homologous sequences are concentrated around the three histidines, which are supposed to form the active site of RNase T2 family RNases.

Primary tumour resection of tongue carcinoma based on response to preoperative therapy

The purpose of this study was to investigate the selection of resection techniques for primary lesions of advanced tongue carcinoma based on the effectiveness of our current preoperative therapy. Forty-three patients with advanced but potentially resectable squamous cell carcinoma of the tongue were included in this study. All patients were treated with preoperative concurrent chemoradiotherapy followed by conventional surgical resection. Semiserial sections of whole surgical specimen of primary lesion were evaluated histopathologically. In patients who achieved 85% and above regression, the extent of residual tumours two-dimensionally and in the deep layers was lesser, and the rate of tumour cell survival was lower, than in other patients. Furthermore, residual tumours tended to be localized to the superficial layers in the centre. These findings suggest that even in advanced tongue carcinomas it is possible to avoid extended resection and perform a less invasive surgery in which the extent of resection is reduced to preserve morphology and function in patients who achieved 65% and above regression following preoperative chemoradiotherapy.

Enzymatic properties of sialic acid binding lectin from Rana catesbeiana modified with a water-soluble carbodiimide in the presence of various nucleophiles

The anti-tumor activity of sialic acid binding lectin from Rana catesbeiana (cSBL) was increased by chemical modification with a water-soluble carbodiimide (EDC) in the presence of nucleophiles such as ethylenediamine and glycine methylester. Investigations on ribonuclease (RNase) activities of the modified cSBLs were conducted to elucidate the fundamental mechanisms underlying enhancement of the anti-tumor activity conferred by these modifications. The following three characteristics were observed with modification. (i) RNase activity of the modified cSBL was enhanced towards double stranded RNA and RNA-oligo dA hybrids. The activity increase was observed even under physiologic ionic strength conditions; (ii) RNase activity of the modified cSBL towards single stranded RNA and poly U decreased, while the activity towards poly C was unaffected; (iii) the base preference of the B2 base recognition site of modified cSBL decreased for guanine. On the contrary, the preference for cytosine and adenine increased. This result may explain why the RNase activity towards poly C was not affected by EDC-modification as mentioned above.

Amino acid sequence of a trypsin inhibitor from a Spirometra (Spirometra erinaceieuropaei)

A trypsin inhibitor that is highly homologous with bovine pancreatic trypsin inhibitor (BPTI) was co-purified along with RNase from Spirometra (Spirometra erinaceieuropaei). The amino acid sequence of this inhibitor (SETI) and the nucleotide sequence of the cDNA encoding this protein were determined by protein chemistry and gene technology. SETI contains 68 amino acid residues and has a molecular mass of 7,798 Da. SETI has 31 amino acid residues that are identical with BPTI's sequence, including 6 half-cystine and 5 aromatic amino acid residues. The active site Lys residue in BPTI is replaced by an Arg residue in SETI. SETI is an effective inhibitor of trypsin and moderately inhibits a-chymotrypsin, but less inhibits elastase or subtilisin. SETI was expressed by E. coli containing a PelB vector carrying the SETI encoding cDNA; an expression yield of 0.68 mg/l was obtained. The phylogenetic relationship of SETI and the other BPTI-like trypsin inhibitors was analyzed using most likelihood inference methods.

Effect of modification of the carboxyl groups of the sialic acid binding lectin from bullfrog (Rana catesbeiana) oocyte on anti-tumor activity

The sialic acid binding lectin from bullfrog Rana catesbeiana oocyte (cSBL) is known to have anti-tumor activity. In order to investigate the relationship between the net charge of cSBL and its anti-tumor effect, cSBL was modified with a water-soluble carbodiimide (EDC) in the presence of three kinds of nucleophiles, taurine, glycine methylester and ethylenediamine. cSBL having four carboxyl groups was partially modified (ca. 2 residues). The anti-tumor activity of modified cSBLs was in the order of ethylenediamine-modified cSBL > glycine methylester-modified cSBL > taurine modified cSBL > or = native cSBL. The results suggested that anti-tumor activity seems to increase with the increase in positive net charge, possibly enhancing the interaction of cSBL with sialoglycoprotein on the surface of tumor cells. The ribonuclease activity of ethylenediamine-modified cSBL decreased with the progress of the reaction, but the number of internalized molecules in the tumor cell increased. Thus, for antitumor activity, a higher incorporation of cSBL with reasonable RNase activity seems to be more important than total RNase activity.

Amino acid sequence and characterization of a rice bran ribonuclease

A base-nonspecific and acid ribonuclease (RNase Os) belonging to the RNase T2 family was purified from rice bran to a homogeneous state by SDS-PAGE. The primary structure of RNase Os was determined by protein chemistry and molecular cloning. The RNase Os was a simple protein and consisted of 205 amino acid residues. Its molecular weight was 22578 and its amino acid sequence showed that it was most similar to barley RNase among the known RNase T2 family enzymes having 157 amino acid residues identical with barley RNase. However, its N-terminus was blocked by a gamma-pyroglutamyl residue. The optimal pH of RNase Os was around 5.5. The base preference at the B1 and B2 site of RNase Os was estimated from the rates of hydrolysis of 16 dinucleoside phosphates, to be guanine as the case of RNase LE from tomato. RNase Os was successfully expressed from yeast cells using the E. coli yeast expression vector pYE-RNAP.

[MR hydrography of the abdomen: technical consideration of data acquisition and future prospects for clinical applications]

Recent advances in MR hydrography have enabled various clinical applications in the areas of abdominal and pelvic disorders, for example, MR cholangiopancreatography (MRCP), MR urography(MRU), and MR hydrography of the fetus. Although the two-dimensional(2D) single-slice method provides excellent information as to the global relationship between lesions and various anatomical structures, small lesions or detailed anatomical characteristics may not be visualized owing to the partial volume effect. Source images of the 2D multislice method are most suitable for the detection of small lesions and detailed evaluation of anatomical structures as "tomographic imaging", while the three-dimensional(3D) method is useful in obtaining data sets for 3D imaging. MR hydrography is a promising method for the noninvasive evaluation of various abdominal disorders, and it has the potential to play new roles in various anatomical regions. However, knowledge of the proper indications is essential for successful clinical application.

Primary non-Hodgkin's lymphoma of the mandible treated with radiotherapy, chemotherapy, and autologous peripheral blood stem cell transplantation

Extranodal presentation in non-Hodgkin's lymphoma (NHL) is uncommon, and the mandible is very rarely involved. Primary NHL of the mandible, for the most part, has intermediate or high malignancy and has a much greater incidence of local recurrence compared with other sites of involvement. A 48-year-old Japanese man with NHL of the mandible received radiotherapy, followed by high-dose chemotherapy supported with peripheral blood stem cell transplantation (PBSCT). High-dose cyclophosphamide, Adriamycin, and vincristine were used for pretransplant conditioning. He achieved complete remission and has survived in continuous complete remission for more than 72 months to date. Marrow-ablative chemotherapy facilitated by PBSCT is thought to be useful as part of the primary therapy for patients with NHL who have poorer prognoses.

Enzymatic properties of phenylalanine101 mutant enzyme of ribonuclease rh from Rhizopus niveus

To investigate the role of Phe101, a component of a base recognition site (B2 site) of a base-nonspecific RNase Rh from Rhizopus niveus, we prepared several enzymes mutated at this position, F101W, F101L, F101I, F101A, F101Q, F101R, and F101K, and their enzymatic activities towards RNA, 16 dinucleoside phosphates, and 2', 3'-cyclic pyrimidine nucleotides were measured. Enzymatic activity toward RNA of F101W, F101L, and F101I were about 7, 20, and 3.8% of the native enzyme, respectively, and those of the other mutants were less than 1% of the RNase Rh. Similar results were also obtained with GpG as substrate. Thus, it was concluded that Phe101 is a very important residue as a component of the B2 site of RNase Rh, and its role could be replaced by Leu, then Trp and Ile, though in less effectively. The results suggested that some kind of interaction between B2 base and the side chain of amino acid residue at the 101th position, such as pi/pi or CH/pi interaction is very important for the enzymatic activity of RNase Rh. The mutation of Phe101 markedly affected the enzymatic activity toward dinucleoside phosphates and polymer substrates, but only moderately the rate of hydrolysis of cyclic nucleotides, indicating the presence of secondary effect of the mutation on B1 site.

Relationship of two ribonucleases with molecular masses of 45 kDa and 37 kDa from the culture medium of Lentinus edodes

Lentinus edodes (shiitake) produces three base non- specific and acid ribonucleases, RNase Le2, RNase Le37 and RNase Le45. The primary structures of the former two RNases, having molecular masses about 24 and 37 kDa, respectively, have been elucidated to be members of the RNase T2 family. The latter two are excreted from mycelia into the medium. In this report, we estimated the primary structure of RNase Le45 using the following experimental evidence. (i) The partial amino acid sequence of RNase Le45 determined that up to about 60% of total protein was identical with that of RNase Le37. (ii) The amino acid composition of RNase Le45 was identical to that of RNase Le37. (iii) The elution profiles on HPLC of lysylendopeptidase and Staphylococcus aureus V8 protease digests of RCM-RNase Le45 (reduced and S-carboxymethylated RNase Le45) were very similar to those of RNase Le37, except for the absence of C-terminus peptide which contained O-glycosylated peptides. However, RNase Le45 contained about 70 residues of mannose and 4 residues of hexosamine. These values were more than twice those of RNase Le37. (iv) RNase Le45 was immunologically indistinguishable from RNase Le37. (v) After treatment with both glycosidase EndoH and alpha-mannosidase, RNases Le37 and Le45 gave complex bands by slab-gel electrophoresis. However, one of the major bands with the highest mobility from RNase Le45 and Le37 showed the molecular mass of 29 kDa in common, which is slightly larger than that of RNase Le2 containing no carbohydrate. These results indicated that RNase Le45 is an enzyme which is a heavily glycosylated species of RNase Le37.

Crystal structure of a plant ribonuclease, RNase LE

Ribonuclease LE (RNase LE) from cultured tomato (Lycopersicon esculentum) cells is a member of the RNase T(2) family showing broad base specificity. The crystal structure of RNase LE has been determined at 1.65 A resolution. The structure consists of seven alpha-helices and seven beta-strands, belonging to an alpha+beta type structure. Comparison of the structure of RNase LE with that of RNase Rh, a microbial RNase belonging to the RNase T(2) family, reveals that while the overall folding topologies are similar to each other, major insertions and deletions are found at the N-terminal regions. The structural comparison, an amino acid sequence alignment of the RNase T(2) enzymes, and comparison of the disulfide-bonding pattern of these enzymes show that the structure of RNase LE shown here is the basic framework of the animal/plant subfamily of RNase T(2) enzymes (including a self-incompatibility protein called S-RNase), and the structure of RNase Rh is that of the fungal subfamily of RNase T(2) enzymes (including RNase T(2)). Subsequently, we superposed the active-site of the RNase LE with that of RNase Rh and found that (1) His39, Trp42, His92, Glu93, Lys96, and His97 of RNase LE coincided exactly with His46, Trp49, His104, Glu105, Lys108, and His109, respectively, of RNase Rh, and (2) two conserved water molecules were found at the putative P(1) sites of both enzymes. These facts suggest that plant RNase LE has a very similar hydrolysis mechanism to that of fungal RNase Rh, and almost all the RNase T(2) enzymes widely distributed in various species share a common catalytic mechanism. A cluster of hydrophobic residues was found on the active-site face of the RNase LE molecule and two large hydrophobic pockets exist. These hydrophobic pockets appear to be base binding sites mainly by hydrophobic interactions and are responsible for the base non-specificity of RNase LE.

Amino acid sequence of a nuclease (nuclease Le1) from Lentinus edodes

The fruit bodies of Lentinus edodes produce two acid nucleases, nucleases Le1 and Le3, both of which are thought to be candidates for the enzymes producing a tasty substance, 5'-GMP. To obtain the basic information on the mechanism of production of 5'-GMP, and structure-function relationship of these nucleases, the primary structure of nuclease Le1 was estimated by both protein chemistry and gene cloning. Nuclease Le1 is a glycoprotein and consists of 290 amino acid residues, and about 2 and 6 residues of hexosamine and neutral sugar, respectively. The nucleotide sequence of cDNA and genomic DNA encoding nuclease Le1 indicated the presence of 20 amino acid residues of a signal peptide. Nuclease Le1 has 115 and 108 residues of identical amino acid residues with nucleases P1 and S, respectively. The amino acid residues concerning the coordination with Zn2+ in nuclease P1 are all conserved in nuclease Le1. Nuclease Le1 contains 8 half-cystine residues and 4 of them are located at the same places as those of nucleases P1 and S.

Amino acids and peptides. LVII. Synthetic peptide with a sequence of ribonuclease from Sulfolobus solfataricus, SSR(1-62), does not function as an RNase

The 62 residue peptide, SSR(1-62), whose sequence corresponds to that of ribonuclease (RNase) from Sulfolobus solfataricus, and its related peptides, SSR(1-22) and SSR(10-62), were chemically synthesized and their RNase activity and DNA-binding activity were examined. The RNase activity assay using yeast RNA or tRNA(fMet) as substrate showed that the synthetic peptide SSR(1-62) did not hydrolyze yeast RNA or tRNA(fMet). These data were not consistent with previous reports that both the native peptide isolated from S. solfataricus [Fusi et al. (1993) Eur. J. Biochem. 211, 305-311] and the recombinant peptide expressed in Escherichia coli [Fusi et al. (1995) Gene 154, 99-103] were able to hydrolyze tRNA(fMet). However, the synthetic SSR(1-62) exhibited DNA-binding activity. In the presence of synthetic SSR(1-62), the cleavage of DNA (plasmid pUCRh2-4) by restriction endonuclease (EcoRI) was not observed, suggesting that synthetic SSR(1-62) bound to DNA protected DNA from its enzymatic digestion. Neither SSR(1-22) nor SSR(10-62) prevented DNA from being cleaved by a restriction enzyme. These findings strongly suggest the importance of not only the N-terminal region of SSR(1-62) but also the C-terminal region for DNA-binding. Circular dichroism spectroscopy of synthetic SSR(1-62) indicated a beta-sheet conformation, in contrast with synthetic SSR(1-22), which exhibited an unordered conformation.

Amino acid sequence of an unique ribonuclease with a C-terminus rich in O-glycosylated serine and threonine from culture medium of Lentinus edodes

The mushroom Lentinus edodes produces three base-non-specific and acid ribonucleases, RNases Le2, Le37, and Le45. The latter two are excreted from mycelia into the medium. The primary structure of RNase Le37, which had a molecular mass of 37 kDa, was sequenced. It was a member of the RNase T2 family, as is RNase Le2. RNase Le37 was some 30 amino acid residues longer at the C-terminal end than RNase Le2. The C-terminal region of RNase LE37 was rich in O-glycosylated serine and threonine. In fungal glucoamylases and chitinases, which hydrolyze raw-starch and chitin, respectively, have structures resembling the structure of the C-terminal of RNase Le37.

Preoperative concurrent chemoradiotherapy plus radical surgery for advanced squamous cell carcinoma of the oral cavity: an analysis of long-term results

Locoregionally advanced squamous cell carcinomas of the head and neck continue to be a major clinical problem. We demonstrated in 1996 that preoperative concurrent cisplatin- or carboplatin-based chemotherapy and radiotherapy plus radical surgery in advanced oral cancer had minimal toxicity, had high clinical tumor response rates, was well tolerated and produced impressive complete response rates and a high 5-year survival rate. The purpose of the present study was the long-term follow-up of this treatment regimen for advanced oral carcinoma. Forty-eight patients with squamous cell carcinoma of the oral cavity (including soft palate) were treated preoperatively with cisplatin- or carboplatin-based chemotherapy in combination with simultaneous irradiation to a target volume of 40 Gy, and 2-6 weeks later underwent curative surgery. All patients with advanced Stage II (n=7), Stage III (n=22) and Stage IV (n=19) were treated and followed for an average of 7.2 years (range: 61-144 months). The overall actuarial survival of all patients was 81.3% at 5 years and also at 10 years. Progression-free survival at both 5 and 10 years was 84.8% for all patients, and 85.7% for Stage II, 90.0% for Stage III, and 78.9% for Stage IV patients. Progression-free survival rates according to the histopathologic regression grade of primary tumor following preoperative chemoradiotherapy at 10 years were 40. 0% for Grade IIa, 88.9% for Grade IIb, 100% for Grade III, and 87.5% for Grade IV. Patients who achieved good responses histopathologically (Grades IIb, III, IV) had superior survival rates in comparison to patients with extensive residual tumor (Grade IIa) in surgically resected specimens (p=0.0012). A better histologic regression grade was also associated with a higher survival rate even in the long-term analysis. This treatment regimen for advanced oral cancer produced high clinical and pathologic complete response and survival rates with an acceptable acute toxicity profile and lack of late therapeutic complications. The long-term follow-up showed gratifying results even for advanced oral cancers without a substantial increase in distant metastasis and second primary malignancy.