Radical Caging Strategy for Cholinergic Optopharmacology

Photo-caged methodologies have been indispensable for elucidating the functional mechanisms of pharmacologically active molecules at the cellular level. A photo-triggered removable unit enables control of the photo-induced expression of pharmacologically active molecular function, resulting in a rapid increase in the concentration of the bioactive compound near the target cell. However, caging the target bioactive compound generally requires specific heteroatom-based functional groups, limiting the types of molecular structures that can be caged. We have developed an unprecedented methodology for caging/uncaging on carbon atoms using a unit with a photo-cleavable carbon-boron bond. The caging/uncaging process requires installation of the CH₂-B group on the nitrogen atom that formally assembles an N-methyl group protected with a photoremovable unit. N-Methylation proceeds by photoirradiation via carbon-centered radical generation. Using this radical caging strategy to cage previously uncageable bioactive molecules, we have photocaged molecules with no general labeling sites, including acetylcholine, an endogenous neurotransmitter. Caged acetylcholine provides an unconventional tool for optopharmacology to clarify neuronal mechanisms on the basis of photo-regulating acetylcholine localization. We demonstrated the utility of this probe by monitoring uncaging in HEK cells expressing a biosensor to detect ACh on the cell surface, as well as Ca²⁺ imaging in Drosophila brain cells (ex vivo).

Reverse mutants of the catalytic 19 kDa mutant protein (nanoKAZ/nanoLuc) from Oplophorus luciferase with coelenterazine as preferred substrate

Native Oplophorus luciferase (OpLase) and its catalytic 19 kDa protein (wild KAZ) show highest luminescence activity with coelenterazine (CTZ) among CTZ analogs. Mutated wild KAZ with 16 amino acid substitutions (nanoKAZ/nanoLuc) utilizes bis-coelenterazine (bis-CTZ) as the preferred substrate and exhibits over 10-fold higher maximum intensity than CTZ. To understand the substrate selectivity of nanoKAZ between CTZ and bis-CTZ, we prepared the reverse mutants of nanoKAZ by amino acid replacements with the original amino acid residue of wild KAZ. The reverse mutant with L18Q and V27L substitutions (QL-nanoKAZ) exhibited 2.6-fold higher maximum intensity with CTZ than that of nanoKAZ with bis-CTZ. The catalytic properties of QL-nanoKAZ including substrate specificity, luminescence spectrum, luminescence kinetics, luminescence products of CTZ, and luminescence inhibition by deaza-CTZ analogs were characterized and were compared with other CTZ-utilizing luciferases such as Gaussia and Renilla luciferases. Thus, QL-nanoKAZ with CTZ could be used as a potential reporter protein for various luminescence assay systems. Furthermore, the crystal structure of QL-nanoKAZ was determined at 1.70 Å resolution. The reverse mutation at the L18Q and V27L positions of α2-helix in nanoKAZ led to changes in the local structures of the α4-helix and the β6- and β7-sheets, and might enhance its binding affinity and oxidation efficiency with CTZ to emit light.

Structure-activity relationship for the folding intermediate-selective inhibition of DYRK1A

DYRK1A phosphorylates proteins involved in neurological disorders in an intermolecular manner. Meanwhile, during the protein folding process of DYRK1A, a transitional folding intermediate catalyzes the intramolecular autophosphorylation required for the "one-off" inceptive activation and stabilization. In our previous study, a small molecule termed FINDY (1) was identified, which inhibits the folding intermediate-catalyzed intramolecular autophosphorylation of DYRK1A but not the folded state-catalyzed intermolecular phosphorylation. However, the structural features of FINDY (1) responsible for this intermediate-selective inhibition remain elusive. In this study, structural derivatives of FINDY (1) were designed and synthesized according to its predicted binding mode in the ATP pocket of DYRK1A. Quantitative structure-activity relationship (QSAR) of the derivatives revealed that the selectivity against the folding intermediate is determined by steric hindrance between the bulky hydrophobic moiety of the derivatives and the entrance to the pocket. In addition, a potent derivative 3 was identified, which inhibited the folding intermediate more strongly than FINDY (1); it was designated as dp-FINDY. Although dp-FINDY (3) did not inhibit the folded state, as well as FINDY (1), it inhibited the intramolecular autophosphorylation of DYRK1A in an in vitro cell-free protein synthesis assay. Furthermore, dp-FINDY (3) destabilized endogenous DYRK1A in HEK293 cells. This study provides structural insights into the folding intermediate-selective inhibition of DYRK1A and expands the chemical options for the design of a kinase inhibitor.

Fluorescent-Oxaboroles: Synthesis and Optical Property by Sugar Recognition

The optical property of fluorescent unit-conjugated aliphatic oxaboroles has been investigated. The oxaboroles provide good fluorescence quantum yields and selective recognition toward D-ribose and D-ribose containing molecules. The molecular recognition induced significant fluorescence quenching. The property of the boroles showed the possibility of the boron-based nicotinamide adenine dinucleotide (NAD) sensor probe.

Generation of Functionalized Alkyl Radicals via the Direct Photoexcitation of 2,2'-(Pyridine-2,6-diyl)diphenol-Based Borates

A new type of alkylborate was developed for the purpose of generating radicals via direct photoexcitation. These borates were prepared using 2,2'-(pyridine-2,6-diyl)diphenol as a tridentate ligand together with organoboronic acids or potassium trifluoroborates. The ready availability of organoboron compounds is a significant advantage of this direct photoexcitation protocol. The excited states of these borates can also serve as strong reductants, enabling various transformations.

Chiral deaza-coelenterazine analogs for probing a substrate-binding site in the Ca2+-binding photoprotein aequorin

The Ca²⁺-binding photoprotein aequorin is a complex of apoAequorin (apoprotein) and (S)-2-peroxycoelenterazine. Aequorin can be regenerated by the incubation of apoAequorin with coelenterazine and molecular oxygen (O₂). In this study, to investigate the molecular recognition of apoAequorin for coelenterazine using chemical probes, the chiral deaza-analogs of (S)- and (R)-deaza-CTZ (daCTZ) for coelenterazine and of (S)-2- and (R)-2-hydroxymethyl-deaza-CTZ (HM-daCTZ) for 2-peroxycoelenterazine were efficiently prepared by the improvement method. The chiral deaza-analogs of (S)-daCTZ and (S)-HM-daCTZ selectively inhibited the regeneration step to aequorin by binding the catalytic site of coelenterazine in the apoAequorin molecule. The crystal structures of the apoAequorin complexes with (S)-daCTZ and (S)-HM-daCTZ were determined, suggesting that the hydroxy moiety at the C6-hydroxyphenyl group and the carbonyl moiety of the imidazopyrazinone ring in coelenterazine are essential to bind the apoAequorin molecule through hydrogen bonding. Therefore, the chiral deaza-analogs of coelenterazine can be used as a probe to study the interaction between coelenterazine and the related proteins including photoprotein, luciferase, and coelenterazine-binding protein.

Direct excitation strategy for radical generation in organic synthesis

This tutorial review encompasses the radical generation based on classical methods and photoredox catalysis. It will also focus on radical generation only demanding visible-light, which involves EDA complex and direct photo-excitation strategy.

Boracene-based alkylborate enabled Ni/Ir hybrid catalysis

Boracene-based alkylborate enabled visible light-mediated metallaphotoredox catalysis. The directly excited borate was easily oxidatively quenched by an excited Ir photoredox catalyst. Ni/Ir hybrid catalysis afforded the products under significantly low irradiance.

Generation of Alkyl Radical through Direct Excitation of Boracene-Based Alkylborate

The generation of tertiary, secondary, and primary alkyl radicals has been achieved by the direct visible-light excitation of a boracene-based alkylborate. This system is based on the photophysical properties of the organoboron molecule. The protocol is applicable to decyanoalkylation, Giese addition, and nickel-catalyzed carbon-carbon bond formations such as alkyl-aryl cross-coupling or vicinal alkylarylation of alkenes, enabling the introduction of various C(sp³) fragments to organic molecules.

A study on an unusual SN2 mechanism in the methylation of benzyne through nickel-complexation

In this study, three reaction mechanisms of a benzyne-nickel (Ni) complex ([Ni(C₆H₄)(dcpe)]) with iodomethane during the methylation process were investigated, namely (a) S_N2 reaction of the benzyne-Ni complex with iodomethane, (b) concerted σ-bond metathesis during the bond breaking/forming processes, and (c) oxidative addition of iodomethane to the Ni-center and the subsequent reductive elimination process. DFT calculations revealed that the reaction barrier of the S_N2 reaction is slightly lower than those of the other mechanisms. The results of orbital analyses suggest that [Ni(C₆H₄)(dcpe)] forms a metallacycle structure between benzyne and the Ni^II (3d⁸) center instead of the η²-structure with the Ni⁰ (3d¹⁰) center. The metallacycle structures became inappropriate as the intermediates of oxidative addition in the formation of the Ni^II-Me bond, avoiding further oxidation to the high-valent Ni^IV. The high free energy along σ-bond metathesis was generated from the steric hindrance, thus invoking methylation and Ni-I bond formation concertedly.

Prenatal neurogenesis induction therapy normalizes brain structure and function in Down syndrome mice

Down syndrome (DS) caused by trisomy of chromosome 21 is the most common genetic cause of intellectual disability. Although the prenatal diagnosis of DS has become feasible, there are no therapies available for the rescue of DS-related neurocognitive impairment. A growth inducer newly identified in our screen of neural stem cells (NSCs) has potent inhibitory activity against dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) and was found to rescue proliferative deficits in Ts65Dn-derived neurospheres and human NSCs derived from individuals with DS. The oral administration of this compound, named ALGERNON (altered generation of neurons), restored NSC proliferation in murine models of DS and increased the number of newborn neurons. Moreover, administration of ALGERNON to pregnant dams rescued aberrant cortical formation in DS mouse embryos and prevented the development of abnormal behaviors in DS offspring. These data suggest that the neurogenic phenotype of DS can be prevented by ALGERNON prenatal therapy.

Nickel-Catalyzed Reductive Cross-Coupling of Aryl Triflates and Nonaflates with Alkyl Iodides

A nickel-catalyzed cross-electrophile coupling of aryl triflates and nonaflates with alkyl iodides using manganese(0) as a reductant is described. The method is applicable to the reductive alkylation of various aryl sulfonates, including o-borylaryl triflate, which enabled efficient construction of diverse alkylated arenes under mild conditions.

Preparation of Aryne-Nickel Complexes from ortho-Borylaryl Triflates

A facile method for preparing diverse aryne-nickel complexes from readily synthesized ortho-borylaryl triflates is described. Exploratory synthetic applications, including the synthesis of 1,2-difunctionalized arenes, based on the nucleophilic character of the aryne-nickel complexes are also demonstrated.

Selective inhibition of the kinase DYRK1A by targeting its folding process

Autophosphorylation of amino-acid residues is part of the folding process of various protein kinases. Conventional chemical screening of mature kinases has missed inhibitors that selectively interfere with the folding process. Here we report a cell-based assay that evaluates inhibition of a kinase at a transitional state during the folding process and identify a folding intermediate-selective inhibitor of dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A), which we refer to as FINDY. FINDY suppresses intramolecular autophosphorylation of Ser97 in DYRK1A in cultured cells, leading to its degradation, but does not inhibit substrate phosphorylation catalysed by the mature kinase. FINDY also suppresses Ser97 autophosphorylation of recombinant DYRK1A, suggesting direct inhibition, and shows high selectivity for DYRK1A over other DYRK family members. In addition, FINDY rescues DYRK1A-induced developmental malformations in Xenopus laevis embryos. Our study demonstrates that transitional folding intermediates of protein kinases can be targeted by small molecules, and paves the way for developing novel types of kinase inhibitors.

Identification of a DYRK1A Inhibitor that Induces Degradation of the Target Kinase using Co-chaperone CDC37 fused with Luciferase nanoKAZ

The protein kinase family includes attractive targets for drug development. Methods for screening of kinase inhibitors remain largely limited to in vitro catalytic assays. It has been shown that ATP-competitive inhibitors antagonize interaction between the target kinase and kinase-specific co-chaperone CDC37 in living cells. Here we show a cell-based method to screen kinase inhibitors using fusion protein of CDC37 with a mutated catalytic 19-kDa component of Oplophorus luciferase, nanoKAZ (CDC37-nanoKAZ). A dual-specificity kinase DYRK1A, an importance of which has been highlighted in Alzheimer's disease, was targeted in this study. We established 293T cells stably expressing CDC37-nanoKAZ, and analyzed interaction between CDC37-nanoKAZ and DYRK1A. We revealed that DYRK1A interacted with CDC37-nanoKAZ. Importantly, point mutations that affect autophosphorylation strengthened the interaction, thus improving signal/noise ratio of the interaction relative to non-specific binding of CDC37-nanoKAZ. This high signal/noise ratio enabled screening of chemical library that resulted in identification of a potent inhibitor of DYRK1A, named CaNDY. CaNDY induced selective degradation of DYRK1A, and inhibited catalytic activity of recombinant DYRK1A with IC50 value of 7.9 nM by competing with ATP. This method based on a mutant target kinase and a bioluminescence-eliciting co-chaperone CDC37 could be applicable to evaluation and development of inhibitors targeting other kinases.

Design and synthesis of a potent inhibitor of class 1 DYRK kinases as a suppressor of adipogenesis

Dysregulation of dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) has been demonstrated in several pathological conditions, including Alzheimer's disease and cancer progression. It has been recently reported that a gain of function-mutation in the human DYRK1B gene exacerbates metabolic syndrome by enhancing obesity. In the previous study, we developed an inhibitor of DYRK family kinases (INDY) and demonstrated that INDY suppresses the pathological phenotypes induced by overexpression of DYRK1A or DYRK1B in cellular and animal models. In this study, we designed and synthesized a novel inhibitor of DYRK family kinases based on the crystal structure of the DYRK1A/INDY complex by replacing the phenol group of INDY with dibenzofuran to produce a derivative, named BINDY. This compound exhibited potent and selective inhibitory activity toward DYRK family kinases in an in vitro assay. Furthermore, treatment of 3T3-L1 pre-adipocytes with BINDY hampered adipogenesis by suppressing gene expression of the critical transcription factors PPARγ and C/EBPα. This study indicates the possibility of BINDY as a potential drug for metabolic syndrome.

Boron-selective biaryl coupling approach to versatile dibenzoxaborins and application to concise synthesis of defucogilvocarcin M

An efficient synthetic method for versatile dibenzoxaborins based on boron-selective Suzuki-Miyaura cross-coupling between o-borylphenols and aryl halides or triflates bearing a 1,8-diaminonaphthalene-protected o-boryl group is reported. A short synthesis of defucogilvocarcin M was achieved using the proposed method in combination with several other boron-mediated transformations.

Involvement of free radicals and oxidative stress in NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) is now the most common liver disease affecting high proportion of the population worldwide. NAFLD encompasses a large spectrum of conditions ranging from fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to cirrhosis and cancer. NAFLD is considered as a multifactorial disease in relation to the pathogenic mechanisms. Oxidative stress has been implicated in the pathogenesis of NAFLD and NASH and the involvement of reactive oxygen species (ROS) has been suggested. Many studies show the association between the levels of lipid oxidation products and disease state. However, often neither oxidative stress nor ROS has been characterized, despite oxidative stress is mediated by multiple active species by different mechanisms and the same lipid oxidation products are produced by different active species. Further, the effects of various antioxidants have been assessed in human and animal studies, but the effects of drugs are determined by the type of active species, suggesting the importance of characterizing the active species involved. This review article is focused on the role of free radicals and free radical-mediated lipid peroxidation in the pathogenesis of NAFLD and NASH, taking characteristic features of free radical-mediated oxidation into consideration. The detailed analysis of lipid oxidation products shows the involvement of free radicals in the pathogenesis of NAFLD and NASH. Potential beneficial effects of antioxidants such as vitamin E are discussed.

Generation of arynes via ate complexes of arylboronic esters with an ortho-leaving group

An efficient method of generating aryne has been achieved by treating ortho-(trifluoromethanesulfonyloxy)arylboronic acid pinacol ester with tert- or sec-butyllithium. Monitoring the reaction by (11)B NMR has indicated that a boron-ate complex formed in situ is the eventual precursor that converts into aryne near room temperature. The prior formation of the ate complex at a low temperature has enabled us to use various arynophiles, including those bearing base-sensitive groups. The ready availability of the aryne precursors and mutual orthogonality in aryne generation with widely used ortho-silylaryl triflate have enhanced the utility of the method.

Correlation of circulating dehydroepiandrosterone with activated protein C generation and carotid intima-media thickness in male patients with type 2 diabetes

AIMS

Dehydroepiandrosterone exerts a protective effect against cardiovascular diseases. However, the relationship of dehydroepiandrosterone with the anticoagulant factor activated protein C, generated by the thrombin-thrombomodulin complex on vascular endothelial cells, remains unknown. This study aimed at studying the relationship between dehydroepiandrosterone and activated protein C generation in patients with Type 2 diabetes.

METHODS

Sixty-two male patients with Type 2 diabetes were enrolled in this study. Data obtained from 40 healthy male subjects were used as controls. The plasma levels of dehydroepiandrosterone, the activated protein C-protein C inhibitor complex, high-sensitivity C-reactive protein and monocyte chemoattractant protein-1 were measured by enzyme immunoassays. Carotid intima-media thickness was measured by ultrasonography.

RESULTS

The plasma levels of dehydroepiandrosterone (5.15 ± 2.81 vs. 3.76 ± 2.16 ng/ml; P < 0.005) and the activated protein C-protein C inhibitor complex (1.90 ± 1.07 vs. 1.02 ± 0.51 ng/ml; P < 0.001) were significantly lower in patients with diabetes than in normal subjects. Univariate analysis showed a significant correlation of the plasma level of dehydroepiandrosterone with that of the activated protein C-protein C inhibitor complex (r = 0.48, P < 0.001), high-sensitivity C-reactive protein (r = -0.30, P < 0.05) and with the mean intima-media thickness (r = -0.28, P < 0.05) in patients with diabetes. Stepwise multiple regression analysis showed that the plasma level of dehydroepiandrosterone is significantly correlated with the plasma levels of the activated protein C-protein C inhibitor complex (F = 18.06) and high-sensitivity C-reactive protein (F = 4.94). There was no correlation between the plasma levels of dehydroepiandrosterone and monocyte chemoattractant protein-1.

CONCLUSIONS

These results suggest that lower circulating levels of dehydroepiandrosterone are associated with decreased activated protein C generation and higher intima-media thickness in patients with Type 2 diabetes.

Primer preactivation of peptidoglycan polymerases

Peptidoglycan glycosyltransferases are highly conserved bacterial enzymes that catalyze glycan strand polymerization to build the cell wall. Because the cell wall is essential for bacterial cell survival, these glycosyltransferases are potential antibiotic targets, but a detailed understanding of their mechanisms is lacking. Here we show that a synthetic peptidoglycan fragment that mimics the elongating polymer chain activates peptidoglycan glycosyltransferases by bypassing the rate-limiting initiation step.

Endoscopic submucosal dissection for colorectal tumors: technical difficulties and rate of perforation

BACKGROUND AND STUDY AIM

Endoscopic submucosal dissection (ESD) for colorectal tumors is not generally recommended because of the technical difficulties and complications, including perforation. These aspects of ESD are thoroughly analyzed in our retrospective study.

PATIENTS AND METHODS

We studied 105 colorectal tumors, from 100 patients, that were treated by ESD at the Kyoto Prefectural University of Medicine or Nara City Hospital between 2005 and 2008. We analyzed tumor size, operation time, rate of en bloc resection, and complications. In addition, we thoroughly investigated the cases of perforation.

RESULTS

The average tumor size was 30.4 mm; average operation time, 102 min; and rate of en bloc resection, 88.5 %. Perforation occurred in 10.4 % of the ESD procedures. Of the 11 perforations, 8 were detected during ESD and treated by clip closure during endoscopy, while 3 were evident only on subsequent routine computed tomography (CT); these were also managed conservatively. A case of postoperative hemorrhage was also observed.

CONCLUSIONS

ESD effectively achieved a high rate of en bloc resection. However, the perforation rate was substantial; hence, improvement in the ESD method is required. The outcomes of ESD, especially for early colorectal malignancies, need to be assessed further.

Preparation of functionally preserved CD4+ CD25high regulatory T cells from leukapheresis products from ulcerative colitis patients, applicable to regulatory T-cell transfer therapy

BACKGROUND

Ulcerative colitis (UC) is an intractable disease; therefore new therapies need to be developed. CD4(+) CD25(high) regulatory T cells (Treg) significantly ameliorate colitis in animal models. In active UC patients, although Treg are functionally preserved, their proportion in peripheral blood decreases. Thus Treg transfer therapy is expected to be efficacious for UC. During leukapheresis for UC, Treg are depleted, as well as colitogenic effector leukocytes. We therefore designed a leukapheresis/Treg transfer therapy in which Treg are isolated from leukapheresis products and transfused to patients, and studied large-scale germ-free methods of Treg preparation.

METHODS

Using the CliniMACS cell selection system, we conducted Treg isolation experiments from leukapheresis products in which B and CD8(+) T cells were depleted, followed by positive selection of CD25(+) cells. In some experiments, isolated Treg or non-Treg were expanded with interleukin-2 (IL-2) +/- transforming growth factor (TGF)-beta1. Expression of a Treg-specific marker, FOXP3, and gut-homing receptors, and suppressor activity of isolated or cultured cells, were analyzed.

RESULTS

CD4(+) CD25(high) T cells were collected and efficiently enriched with a good recovery rate. Isolated cells preferentially expressed FOXP3 and significantly suppressed T-cell proliferation in vitro. In addition, isolated Treg could be efficiently expanded, and Treg could be induced from non-Treg with TGF-beta1 in vitro. TGF-beta1 significantly up-regulated alphaEbeta7 and alpha4beta7 integrins.

DISCUSSION

We have established a method of Treg isolation from leukapheresis products that can be used clinically; therefore, Treg transfer therapy is feasible in combination with leukapheresis for UC. Expansion or induction of Treg in vitro may be another approach to Treg-based immunotherapy.

Impact of double-balloon endoscopy on the diagnosis of jejunoileal involvement in primary intestinal follicular lymphomas: a case series

In recent years, primary gastrointestinal follicular lymphoma has been increasingly detected in the duodenum on esophagogastroduodenoscopy (EGD). Primary gastrointestinal follicular lymphomas are frequently distributed to multiple sites in the gastrointestinal tract. Therefore, investigation into the spread of follicular lymphomas in the small bowel is important in order to determine the most appropriate treatment strategy. The performance of double-balloon endoscopy (DBE) in the diagnosis of jejunoileal follicular lymphoma lesions has not been fully evaluated. We aimed to investigate the value of DBE in addition to computed tomography (CT) and (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) in the diagnosis of jejunoileal follicular lymphoma. DBE with biopsy was performed in seven patients with primary duodenal follicular lymphoma diagnosed by EGD, in order to investigate jejunoileal involvement. Jejunoileal follicular lymphoma lesions were detected by DBE in six out of the seven patients (three in the jejunum and three in the jejunum and ileum), whereas CT and (18)F-FDG-PET failed to detect the existence of these lesions. Endoscopic findings of the jejunoileal lesions revealed multiple white nodules and white villi, which were similar to those of duodenal lesions. DBE was more useful for the diagnosis of jejunoileal involvement in primary intestinal follicular lymphoma than CT and (18)F-FDG-PET. The use of DBE will become important for determining the most appropriate treatment for gastrointestinal follicular lymphoma.

Comparison of survival between anatomic and non-anatomic liver resection in patients with hepatocellular carcinoma: significance of surgical margin in non-anatomic resection

AIMS

Anatomic resection, i.e., systematic removal of a liver segment confined by portal branches, is theoretically effective in eradicating intrahepatic metastasis of hepatocellular carcinoma (HCC). The procedure may reduce tumour recurrence and enhance survival of HCC patients. To determine the significance of anatomic resection for HCC patients, we retrospectively conducted a comparative analysis between anatomic (AR) and non-anatomic liver resection (NAR) in 113 Japanese HCC patients with a solitary tumour, a tumour located within one segment, absence or invasion of distal to second order branches of the portal vein, and absence or invasion of peripheral branches of the hepatic vein.

METHODS

Patients were divided into two groups, AR group (n = 49) and NAR group (n = 64).

RESULTS

The prevalence of liver damage Grade B in the NAR group was significantly greater than in the AR group (p < 0.05). Tumour-free and overall survival following liver resection was not significantly different between AR and NAR groups. In the NAR group, tumour-free and overall survival in patients with tumour exposure at the surgical margin was significantly lower than with a surgical margin greater than 0 mm (not exposed) (p < 0.05). Survival between the AR and NAR groups without tumour exposure at the surgical margin was similar.

CONCLUSIONS

Anatomic resection is the theoretical aim. In HCC patients with impaired liver functions, limited liver resection without tumour exposure may provide longer tumour-free and overall survival.

Trisectionectomy for large hepatocellular carcinoma using the liver hanging maneuver

BACKGROUND/PURPOSE

Large liver tumors often expand and severely compress intrahepatic vessels. In cases of the trisectionectomy for such tumors, however, it is difficult to adequately expose the transection planes. The liver hanging maneuver (LHM) is a useful technique for hemihepatectomy and an adequate transection plane might be also required in trisectionectomy.

METHODS

LHM procedure is basically followed by the Belghiti's method. A nasogastric tube was used for hanging. At the hepatic hilum, the tube was placed between the liver and Glisson's pedicle.

RESULTS

We report here the application of LHM for right and left trisectionectomy in patients with a large hepatoma in two cases. In case of a right trisectionectomy for a large tumor compressing the umbilical Glisson's pedicle, an adequate transection plane was obtained using the LHM because the resected and remnant livers rotated to the other side upon lifting the tube during transection. In case of a left trisectionectomy for a large hepatic tumor compressing the right hepatic vein, an adequate transection plane along the right hepatic vein was obtained using LHM as well.

CONCLUSIONS

LHM is a useful surgical application for right and left trisectionectomy in patients with large liver tumors compressing the cut plane.

Protective role of thrombin activatable fibrinolysis inhibitor in obstructive nephropathy-associated tubulointerstitial fibrosis

BACKGROUND

Thrombin-activatable fibrinolysis inhibitor (TAFI) has been reported to affect wound healing and fibrotic processes, but its role in renal tubulointerstitial fibrosis remains unknown.

OBJECTIVE

To study its potential role, we compared TAFI-deficient and wild-type mice for the degree of renal fibrosis caused by unilateral ureteral obstruction (UUO).

METHODS

The grade of tubulointerstitial fibrosis, the activity of plasmin, MMP-2 and MMP-9 were evaluated on days 4 and 9 after UUO.

RESULTS

The renal content of hydroxyproline and the activity of plasmin, MMP-2 and MMP-9 were significantly increased in kidneys with UUO from TAFI-deficient mice compared with those from wild-type mice. These differences disappeared when animals with UUO from both groups were treated with the plasmin inhibitor tranexamic acid. The renal concentrations of fibrogenic cytokines were also significantly elevated in kidneys with UUO from TAFI-deficient mice compared with those from wild-type mice.

CONCLUSION

The results of this study suggest that increased renal activity of plasmin in TAFI-deficient mice causes increased renal interstitial fibrosis in obstructive nephropathy.

Inverse correlation between activated protein C generation and carotid atherosclerosis in Type 2 diabetic patients

AIMS

Activated protein C (APC) is a key regulator of the clotting system and immune responses. We studied the relationship between the degree of atherosclerosis as measured by the intima-media thickness (IMT) of carotid artery and APC generation in Type 2 diabetic patients.

METHODS

Eighty-seven Type 2 diabetic patients and 35 control subjects participated. APC generation was assessed by the plasma APC-protein C inhibitor complex (APC-PCI) levels and the mean IMT of carotid artery was measured by ultrasonography. The plasma levels of the thrombin-anti-thromobin complex (TAT) and platelet-derived growth factor (PDGF) were measured by enzyme-linked immunoassays.

RESULTS

Plasma TAT levels were significantly higher in diabetic patients [2.03 (1.12, 2.56) ng/ml, median (25th, 75th percentile)] compared with control subjects [0.85 (0.55, 2.08) ng/ml, P < 0.01]. Plasma APC-PCI levels were significantly lower in diabetic patients [0.93 (0.74, 1.22) ng/ml], than in control subjects [1.66 (1.25, 2.36) ng/ml, P < 0.001]. The mean IMT was significantly increased in diabetic patients (0.881 +/- 0.242 mm; mean +/- sd) compared with control subjects (0.669 +/- 0.140 mm; P < 0.01). Univariate analysis showed a significant and inverse correlation between plasma APC-PCI levels and mean IMT (r = -0.32, P < 0.005), and multivariate regression analysis confirmed the independent correlation (P < 0.05). Moreover, plasma APC-PCI levels significantly and inversely correlated with plasma PDGF levels in diabetic patients (r = -0.30, P < 0.01).

CONCLUSIONS

These results suggest that decreased APC generation is associated with vascular atherosclerotic changes in Type 2 diabetic patients.