A rational design strategy of radical-type mechanophores with thermal tolerance

Radical-type mechanophores (RMs) are attractive molecules that undergo homolytic scission of their central C-C bond to afford radical species upon exposure to heat or mechanical stimuli. However, the lack of a rational design concept limits the development of RMs with pre-determined properties. Herein, we report a rational design strategy of RMs with high thermal tolerance while maintaining mechanoresponsiveness. A combined experimental and theoretical analysis revealed that the high thermal tolerance of these RMs is related to the radical-stabilization energy (RSE) as well as the Hammett and modified Swain-Lupton constants at the para-position (σp). The trend of the RSE values is in good agreement with the experimentally evaluated thermal tolerance of a series of mechanoresponsive RMs based on the bisarylcyanoacetate motif. Furthermore, the singly occupied molecular orbital (SOMO) levels clearly exhibit a negative correlation with σp within a series of RMs that are based on the same skeleton, paving the way toward the development of RMs that can be handled under ambient conditions without peroxidation.

Intramolecular Palladium Catalyst Transfer on Benzoheterodiazoles as Acceptor Monomers and Discovery of Catalyst Transfer Inhibitors

Intramolecular catalyst transfer on benzoheterodiazoles was investigated in Suzuki-Miyaura coupling reactions and polymerization reactions with t Bu3 PPd precatalyst. In the coupling reactions of dibromobenzotriazole, dibromobenzoxazole, and dibromobenzothiadiazole with pinacol phenylboronate, the product ratios of monosubstituted product to disubstituted product were 0/100, 27/73, and 89/11, respectively, indicating that the Pd catalyst undergoes intramolecular catalyst transfer on dibromobenzotriazole, whereas intermolecular transfer occurs in part in the case of dibromobenzoxazole and is predominant for dibromobenzothiadiazole. The polycondensation of 1.3 equivalents of dibromobenzotriazole with 1.0 equivalent of para- and meta-phenylenediboronates afforded high-molecular-weight polymer and cyclic polymer, respectively. In the case of dibromobenzoxazole, however, para- and meta-phenylenediboronates afforded moderate-molecular-weight polymer with bromine at both ends and cyclic polymer, respectively. In the case of dibromobenzothiadiazole, they afforded low-molecular-weight polymers with bromine at both ends. Addition of benzothiadiazole derivatives interfered with catalyst transfer in the coupling reactions.

Theoretical and Experimental Investigations of Stable Arylfluorene-Based Radical-Type Mechanophores

Invited for the cover of this issue are the groups of Hideyuki Otsuka at the Tokyo Institute of Technology and Koichiro Mikami at the Sagami Chemical Research Institute. The image depicts theoretical and experimental investigations of stable arylfluorene-based radical-type mechanophores. Read the full text of the article at 10.1002/chem.202203249.

Theoretical and Experimental Investigations of Stable Arylfluorene-Based Radical-Type Mechanophores

Radical-type mechanophores (RMs) can undergo homolytic cleavage of their central C-C bonds upon exposure to mechanical forces, which affords radical species. Understanding the characteristics of these radical species allows bespoke mechanoresponsive materials to be designed and developed. The thermal stability of the central C-C bonds and the oxygen tolerance of the generated radical species are crucial characteristics that determine the functions and applicability of such RM-containing mechanoresponsive materials. In this paper, we report the synthesis and characterization of two series of arylfluorene-based RM derivatives, that is, 9,9'-bis(5-methyl-2-pyridyl)-9,9'-bifluorene (BPyF) and 9,9'-bis(4,6-diphenyl-2-triazyl)-9,9'-bifluorene (BTAF). BPyF and BTAF derivatives were synthesized without generating any peroxides initially, albeit that BPyF slowly converted to the corresponding peroxide in solution. DFT calculations revealed the importance of the thermodynamic stability and the values of the α-SOMO levels of the corresponding radical species for their thermal stability and oxygen tolerance. Furthermore, the mechanochromism of BTAF was demonstrated by ball-milling a BTAF-centered polymer, which was synthesized by atom-transfer radical polymerization (ATRP).

Mechanochemical Reactions of Bis(9-methylphenyl-9-fluorenyl) Peroxides and Their Applications in Cross-Linked Polymers

The exploration of mechanochemical reactions has brought new opportunities for the design of functional materials. We synthesized the novel organic peroxide mechanophore bis(9-methylphenyl-9-fluorenyl) peroxide (BMPF) and examined its mechanochromic properties. The mechanism behind its mechanofluorescence was clarified and harnessed in polymer networks that can release the small fluorescent molecule 9-fluorenone upon exposure to a mechanical stimulus. Additionally, polymer networks cross-linked with BMPF units are able to tolerate temperatures up to 110 °C without any change in optical properties or mechanical strength. As mechanophores based on organic peroxide have rarely been documented so far, these fascinating results suggest excellent potential for applications of BMPF in stress-responsive materials. The mechanochemical protocol demonstrated here may provide guiding principles to expand the field of mechanochromic peroxides.

Segmented Polyurethane Elastomers with Mechanochromic and Self-Strengthening Functions

Mechanochromic elastomers that exhibit force-induced cross-linking reactions in the bulk state are introduced. The synthesis of segmented polyurethanes (SPUs) that contain difluorenylsuccinonitrile (DFSN) moieties in the main chain and methacryloyl groups in the side chains was carried out. DFSN was selected as the mechanophore because it dissociates under mechanical stimuli to form pink cyanofluorene (CF) radicals, which can also initiate the radical polymerization of methacrylate monomers. The obtained elastomers generated CF radicals and changed color by compression or extension; they also became insoluble due to the mechanically induced cross-linking reactions. Additionally, an SPU containing diphenylmethane units also exhibited highly sensitive mechanofluorescence. To the best of our knowledge, this is the first report to demonstrate damage detection ability and changes in the mechanical properties of bulk elastomers induced by simple compression or extension.

Non-symmetric mechanophores prepared from radical-type symmetric mechanophores: bespoke mechanofunctional polymers

A non-symmetric radical-type mechanophore (CF/ABF) was synthesized by molecular crossing between two radical-type mechanophores. The thermal stability and mechanoresponsiveness of CF/ABF were found to be tunable by altering the properties of the parent RMs. The CF/ABF-centred polymers showed mixed mechanochromism derived from the simultaneous generation of two radical species.

P5632Different impact of lesion length on fractional flow reserve in intermediate coronary lesions between each coronary artery

Background

Previous studies reported that lesion length was an important geometric parameter in addition to the degree of stenosis in the determinant of functional significance of coronary artery stenosis. Nevertheless, the optimal cutoff value of lesion length for predicting functional significance for each coronary artery has not yet been evaluated, though previous studies revealed that the cutoff value of minimum lumen diameter measured on coronary angiography (CAG) to predict fractional flow reserve (FFR) <0.80 is different for each coronary artery

Purpose

This study evaluated whether the impact of lesion length on functional significance is similar between each coronary artery for lesions with intermediate stenosis.

Methods

Patients with suspected coronary artery disease who had at least one intermediate coronary lesion (luminal diameter stenosis of 70 to 80% by visual estimation on CAG) and underwent FFR measurement for the evaluation of myocardial ischemia were evaluated. Quantitative coronary angiography analysis including percent diameter stenosis and lesion length was performed. FFR was measured as the ratio of the mean distal coronary artery pressure to the mean aortic pressure during maximal hyperemia induced by intravenous infusion of adenosine triphosphate (150 μg /kg/min). The area under the receiver operating characteristics (ROC) curve was estimated for the best cutoff value as a predictor of FFR value of ≤0.80 for each coronary artery.

Results

A total of 221 de novo lesions that underwent FFR measurement were enrolled. The average FFR value was 0.81±0.07. Although lesion length was similar among the lesions with an FFR >0.80 at different locations, the mean lesion length was significantly longer for lesions in the right coronary artery (RCA) with an FFR ≤0.80 than for those in the left anterior descending artery (LAD) and left circumflex artery (13.4±3.4 versus 8.6±3.1 versus 12.0±3.7 mm, p<0.001). ROC analysis demonstrated that the optimal cutoff value of lesion length for predicting an FFR ≤0.80 was 10.0 mm in the LAD (0.56 area under the curve, 48% sensitivity, 76% specificity), whereas 13.1 mm in the RCA (0.84 area under the curve, 67% sensitivity, 93% specificity) (Figure).

ROC analysis of LL for FFR≤0.80

Conclusions

A longer lesion length is required to achieve FFR<0.80 in the RCA than in the other arteries. This may suggest the low possibility of an FFR ≤0.80 when stenosis is focal and short in the RCA with stenosis of 70 to 80% by visual estimation on CAG.

Intramolecular Catalyst Transfer on a Variety of Functional Groups between Benzene Rings in a Suzuki-Miyaura Coupling Reaction

Suzuki-Miyaura coupling reaction of BrC₆ H₄ -X-C₆ H₄ Br 1 (X=CH₂ , CO, N-Bu, O, S, SO, and SO₂ ) with arylboronic acid 2 was investigated in the presence of tBu₃ PPd precatalyst and CsF/[18]crown-6 as a base to establish whether or not the Pd catalyst can undergo catalyst transfer on these functional groups. In the reaction of 1 (X=CH₂ , CO, N-Bu, O, and SO₂ ) with 2, aryl-disubstituted product 3 (Ar-C₆ H₄ -X-C₆ H₄ -Ar) was exclusively obtained, indicating that the Pd catalyst undergoes catalyst transfer on these functional groups. On the other hand, the reaction of 1 e (X=S) and 1 f (X=SO) with 2 afforded only aryl-monosubstituted product 4 (Ar-C₆ H₄ -X-C₆ H₄ -Br) and a mixture of 3 and 4, respectively, indicating that S and SO interfere with intramolecular catalyst transfer. Furthermore, we found that Suzuki-Miyaura polycondensation of 1 (X=CH₂ , CO, N-Bu, O, and SO₂ ) and phenylenediboronic acid 5 in the presence of tBu₃ PPd precatalyst afforded high-molecular-weight polymer even when excess 1 was used. The polymers obtained from 1 (X=CH₂ , N-Bu, and O) and 5 turned out to be cyclic.

Unstoichiometric Suzuki–Miyaura cyclic polymerization of extensively conjugated monomers

Suzuki–Miyaura polycondensation of an excess of extensively conjugated aromatic dibromide with 1.0 equivalent of phenylenediboronate in the presence of ^tBu₃PPd(0) precatalyst afforded cyclic polymers.

Characteristics of arsenic in humic substances extracted from natural organic sediments

The stability and dispersion of naturally occurring As have been receiving increasing attention, because As is toxic and its contamination is a widespread problem in many countries. This study investigated As fractionation and speciation in organic sediments collected from different depositional settings to elucidate the existence of stable As in humic substances. Eleven organic sediment samples were collected from marine and terrestrial alluvial regions in Hokkaido prefecture, Japan, and the chemical fraction of As and species of humic substances were identified by sequential extraction. In addition, stable As bound in organic matter was evaluated by FT-IR spectroscopy. The As fraction mainly comprised inorganic substances, especially sulfur, iron, and manganese, and terrestrial sediments (lacustrine and inland deposits) were rich in sulfides and Fe and Al (hydr)oxides. When the residual fraction was excluded, the organic fraction of As was higher in seawater sediments than in terrestrial sediments. Among humic substances, cellulose, humic acid, and hydrophilic fulvic acid were clearly associated with As accumulation, and As speciation showed that the As was of organic origin. Cellulose, an organic compound of plant origin, was abundant in As=S and As (III)=O bonds, and As accumulation was higher in sulfur-rich peat sediments, corresponding with the physiological activities of As in plants. Hydrophilic fulvic acid and humic acid in these sediments, originating from small animals and microorganisms in addition to plants, denote higher As contents and abound in As (III, V)=C and C-H, CH₃ bonds even in sulfur-rich sediments. The methylated As bonds reflect the ecological transition of organisms.

Unusual cyclic polymerization through Suzuki-Miyaura coupling of polyphenylene bearing diboronate at both ends with excess dibromophenylene

The Suzuki-Miyaura coupling polymerization of p-dibromophenylene and m-phenylenediboronic acid ester, as well as m-dibromophenylene and p-phenylenediboronic acid ester, and the combination of two meta-phenylene monomers in the presence of the t-Bu₃PPd(0) catalyst selectively afforded cyclic polyphenylenes with polyphenylene bearing boronate moieties at both ends when excess dibromophenylene was used.

A prospective study of total plasma cell-free DNA as a predictive biomarker for response to systemic therapy in patients with advanced non-small-cell lung cancers

BACKGROUND

While previous studies have reported on the prognostic value of total plasma cell-free deoxyribonucleic acid (cfDNA) in lung cancers, few have prospectively evaluated its predictive value for systemic therapy response.

PATIENTS AND METHODS

We conducted a prospective study to evaluate the association between changes in total cfDNA and radiologic response to systemic therapy in patients with stage IIIB/IV non-small-cell lung cancers (NSCLCs). Paired blood collections for cfDNA and computed tomography (CT) assessments by RECIST v1.0 were performed at baseline and 6-12 weeks after therapy initiation. Total cfDNA levels were measured in plasma using quantitative real-time polymerase chain reaction. Associations between changes in cfDNA and radiologic response, progression-free survival (PFS), and overall survival (OS) were measured using Kruskal-Wallis and Kaplan-Meier estimates.

RESULTS

A total of 103 patients completed paired cfDNA and CT response assessments. Systemic therapy administered included cytotoxic chemotherapy in 57% (59/103), molecularly targeted therapy in 17% (17/103), and combination therapy in 26% (27/103). Median change in cfDNA from baseline to response assessment did not significantly differ by radiologic response categories of progression of disease, stable disease and partial response (P = 0.10). However, using radiologic response as continuous variable, there was a weak positive correlation between change in radiologic response and change in cfDNA (Spearman's correlation coefficient 0.21, P = 0.03). Baseline cfDNA levels were not associated with PFS [hazard ratio (HR) = 1.06, 95% confidence interval (CI) 0.93-1.20, P = 0.41] or OS (HR = 1.04, 95% CI 0.93-1.17, P = 0.51), neither were changes in cfDNA.

CONCLUSIONS

In this large prospective study, changes in total cfDNA over time did not significantly predict radiologic response from systemic therapy in patients with advanced NSCLC. Pretreatment levels of total cfDNA were not prognostic of survival. Total cfDNA level is not a highly specific predictive biomarker and future investigations in cfDNA should focus on tumor-specific genomic alterations using expanded capabilities of next-generation sequencing.

Prognostic value of tropomyosin-related kinases A, B, and C in gastric cancer

PURPOSE

Tropomyosin-related kinase (Trk) receptors play critical roles in tumor development and are considered attractive targets for cancer therapy. We investigated correlations of the expression of TrkA, TrkB, and TrkC with clinicopathological features and outcomes in gastric cancer.

METHODS

Tumor samples were obtained from 221 patients with gastric cancer who underwent gastrectomy between 2003 and 2007. The expression of TrkA, TrkB, and TrkC was analyzed using immunohistochemical staining. The relationship of their expression to clinicopathological factors and outcomes was assessed.

RESULTS

High expression of TrkA, TrkB, or TrkC was significantly associated with histopathology (p = 0.022, p < 0.001, and p < 0.001). High expression of TrkA was significantly correlated with variables related to tumor progression, including lymph node metastasis (p = 0.024) and distant metastasis or recurrence (p < 0.001). Distant metastasis or recurrence was found in a significantly higher proportion of patients with high expression of TrkC than in those with low expression (p = 0.036). High expression of TrkA was significantly associated with poorer relapse-free survival (RFS) in univariate analysis (p = 0.001). High expression of TrkA or TrkC was significantly associated with poorer disease-specific survival (DSS) in univariate analysis (p < 0.001 and p = 0.008). In multivariate analysis, TrkA was an independent predictor of RFS [hazard ratio (HR), 2.294; 95 % confidence interval (CI), 1.309-4.032; p = 0.004] and DSS (HR, 2.146; 95 % CI, 1.195-3.861; p = 0.011). Expression of TrkB was not associated with RFS or DSS in univariate analysis.

CONCLUSIONS

Our results demonstrated that TrkA expression was associated with tumor progression and poor survival, and was an independent predictor of poor outcomes in gastric cancer patients.

Patterns, timing and risk factors of recurrence of gastric cancer after laparoscopic gastrectomy: reliable results following long-term follow-up

BACKGROUND

To clarify the patterns, timing and risk factors of recurrence of gastric cancer after laparoscopic gastrectomy.

METHODS

From January 1999 to March 2012, 577 patients underwent laparoscopic or laparoscopy-assisted gastrectomy for curative resection of gastric cancer. Recurrence patterns were classified as locoregional, hematogenous, peritoneal, distant lymph node and mixed. Recurrence patterns and time to recurrence were retrospectively examined and risk factors for recurrence were analyzed.

RESULTS

Recurrence occurred in 28 (4.9%) cases with patterns as follows: locoregional in 2 patients (7.1%), hematogenous in seven (25.0%), peritoneal in nine (32.1%), distant lymph node in four (14.3%), and mixed in 6 (21.4%). There was no recurrence pattern peculiar to laparoscopic surgery. Recurrence occurred at one site in 21 patients (78.6%), two in 4 patients (14.3%), and three in 2 patients (7.1%). The median time to recurrence was 384 days (range 83-1497 days). Recurrence was detected within a year in 13 cases (46.4%), within two years in 21 (75%), and within three years in 25 (89.3%). Univariate analysis revealed tumor location, tumor size, type of operation, tumor depth, and lymph node classification as risk factors for recurrence. Multivariate analysis indicated tumor depth and lymph node classification as risk factors of recurrence.

CONCLUSIONS

Patterns, timing and risk factors of recurrence of gastric cancer after laparoscopic gastrectomy are similar to those after open gastrectomy, with no peculiarities specific to laparoscopic gastrectomy. Thus, as long as laparoscopic gastrectomy is performed according to the present inclusion criteria, follow-up can be similarly performed as for open gastrectomy.

Statins inhibit tumor progression via an enhancer of zeste homolog 2-mediated epigenetic alteration in colorectal cancer

While statin intake has been proven to reduce the risk of colorectal cancer (CRC), the mechanism of antitumor effects and clinical significance in survival benefits remain unclear. Statin-induced antiproliferative effects and its underlying mechanism were examined using six CRC cell lines. Statins except pravastatin showed antiproliferative effects (simvastatin ≥ fluvastatin > atorvastatin) even though both of simvastatin and pravastatin could activate mevalonate pathways, suggesting the statin-mediated antiproliferative effects depended on non-mevalonate pathway. Indeed, statin induced p27(KIP1) expression by downregulation of histone methyltransferase enhancer of zeste homolog 2 (EZH2), which acts as an epigenetic gene silencer. Additionally, the use of simvastatin plus classII histone deacetylase (HDAC) inhibitor (MC1568) induced further overexpression of p27(KIP1) by inhibiting HDAC5 induction originated from downregulated EZH2 in CRC cells and synergistically led to considerable antiproliferative effects. In the clinical setting, Statin intake (except pravastatin) displayed the downregulated EZH2 expression and inversely upregulated p27(KIP1) expression in the resected CRC by immunohistochemical staining and resulted in the significantly better prognoses both in overall survival (p = 0.02) and disease free survival (p < 0.01) compared to patients without statin intake. Statins may inhibit tumor progression via an EZH2-mediated epigenetic alteration, which results in survival benefits after resected CRC. Furthermore, statin plus classII HDAC inhibitor could be a novel anticancer therapy by their synergistic effects in CRC.

Distal pancreatectomy using a no-touch isolation technique

BACKGROUND AND AIMS

Distal pancreatectomy is the only effective treatment for cancers of the pancreatic body and tail. The recurrence rate after DP has remained high. In an effort to over-come this problem, we developed a no-touch surgical technique for DP. This is a pilot study to see if distal pancreatectomy can be technically done using a no-touch surgical technique with-out deteriorating the post-operative prognosis.

PATIENTS AND METHODS

From November 2000 through May 2011, 16 pancreatic ductal adeno-carcinoma patients have been operated on using a no-touch technique by a single operator. We described the surgical technique, and we reported our preliminary experience. During the procedure, the pancreatic body and tail is neither grasped nor squeezed by the surgeon. And all drainage vessels from the pancreatic body and tail are ligated and divided during the early phase of the operation. Furthermore, for improved dissection of the retroperitoneal tissue (rightward and posterior margins), we use a hanging and clamping maneuver and dissection behind Gerota's fascia.

RESULTS

In the current series, the posterior and rightward resection margins were free in all patients, although seven were positive for anterior serosal invasion. The post-operative prognosis was not deteriorated with this technique.

CONCLUSION

No-touch distal pancreatectomy technique may have some theoretical advantages, which merit future investigation in randomized controlled trials.

Effect of the C-terminal domain of Vibrio proteolyticus chitinase A on the chitinolytic activity in association with pH changes

AIMS

To reveal the cause of the difference in activity of chitinase A from Vibrio proteolyticus and chitinase A from a strain of Vibrio carchariae (a junior synonym of Vibrio harveyi), we investigated the pH-dependent activity of full-length V. proteolyticus chitinase A and a truncated recombinant corresponding to the V. harveyi form of chitinase A.

METHODS AND RESULTS

After overexpression in Escherichia coli strain DH5α, the full-length and truncated recombinant chitinases were purified by ammonium sulphate precipitation and anion exchange column chromatography. Chitinase activity was measured at various pH values using α-crystal and colloidal chitins as the substrate. The pH-dependent patterns of the relative specific activities for α-crystal chitin differed between the full-length and truncated recombinant chitinases, whereas those for colloidal chitin were similar to each other.

CONCLUSION

The difference in the activity of V. proteolyticus chitinase A and V. harveyi chitinase A might be partly due to a change in the pH dependence of the chitinase activities against α-crystal chitin, resulting from C-terminal processing.

SIGNIFICANCE AND IMPACT OF STUDY

The present results are important findings for not only ecological studies on the genus Vibrio in association with survival strategies, but also phylogenetic studies.

Leaching behavior of CRT funnel glass

The leaching behavior of cathode ray tube (CRT) funnel glass containing 23 mass percent of Pb in 0.001 N HCl, distilled water, and 0.001 N NaOH at 90°C was investigated using a static method. The weight loss and leached amount of each component was measured and surface changes observed by SEM. The leaching mechanism is discussed. In acid solution, the leached amount of Pb showed t(1/2) dependence, that is, diffusion-controlled dependence, which is common in lead silicate glasses. In water and basic solutions, the leached amount showed saturation after higher initial dissolution than in acid and the deposition of many particles on the surface was observed. The amount leached was less for Pb than other components. The deposited particles formed a protective layer, which suppressed the dissolution of the glass. This dense layer must be formed as a result of a high initial dissolution rate.

Identification of Aeromonas species isolated from freshwater fish with the microplate hybridization method

Aeromonas isolates were obtained from the intestinal tracts of six species of cultured freshwater fish and identified on the basis of their genotypic and phenotypic characters. The microplate hybridization method could differentiate type strains of Aeromonas species and related bacteria. DNA-DNA hybridization analysis showed that 65 aeromonad isolates were 72 to 100% related with either Aeromonas caviae, Aeromonas hydrophila, Aeromonas jandaei, Aeromonas sobria, or Aeromonas veronii. As many as 48% of the genotypically identified A. caviae, A. hydrophila, and A. sobria isolates differed from the type strains of corresponding species in one to three phenotypic characters. These results strongly suggest that not all aeromonad isolates from freshwater fish could be identified correctly on the basis of only the phenotypic characters, indicating the usefulness of the microplate hybridization method for the identification of aeromonads.

Distribution and species composition of juvenile and adult scombropids (Teleostei, Scombropidae) in Japanese coastal waters

Two scombropid fishes, Scombrops boops and Scombrops gilberti, are closely related and commercially important species in Japan. These species are often confused in commercial markets because of their morphological similarity. In this study, scombropid specimens collected from various Japanese coastal waters were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and phylogenetic analysis of the 16S rRNA gene in mitochondrial DNA. These analyses showed that all the scombropid specimens collected from localities in the Sea of Japan were identified as S. boops, whereas those from the Pacific Ocean included two species, S. boops and S. gilberti. Almost all juvenile (<200 mm standard body length, S(L)) S. gilberti originated from the Pacific coastal waters of the northern Japan, whereas adults (>400 mm S(L)) were found only in deep water off the Izu Peninsula to the Izu Islands. This suggests that S. gilberti might migrate extensively during its life cycle. In addition, differences in the number of specimens and the distribution between the two species suggest that S. gilberti is less abundant than S. boops in Japanese waters.

Measurement and calculation of radioactivities of spallation products by high-energy heavy ions

Irradiation experiments were performed at the HIMAC (Heavy Ion Medical Accelerator in Chiba) facility, National Institute of Radiological Sciences, Japan. The radioactivity distributions of spallation products in a thick Cu target were obtained by irradiating 230 and 100MeV/nucleon Ne, C, He, p and 230MeV/nucleon Ar ions. The gamma-ray spectra from thin irradiated samples of C, Al and Cu inserted into a Cu target were measured with a HPGe detector. From the gamma-ray spectra, we obtained the spatial distribution of radioactive yields of spallation products of about 40 nuclides in Cu sample in the Cu target. Our results agree with other experimental data. We also calculated the spatial distribution of residual radioactivities in the Cu target by the PHITS (Particle and Heavy-Ion Transport code System) code and compared with measured results. The PHITS code provides good results on residual activity calculations.

Smoking-related changes in the background lung of specimens resected for lung cancer: a semiquantitative study with correlation to postoperative course

AIMS

To assess the pathological findings in lobectomy specimens, to correlate them with smoking history and postoperative course and to compare the findings with those in smoking-related interstitial lung disease.

METHODS AND RESULTS

Patients who had undergone lobectomy for lung cancer were reviewed. Subjects included 230 non-smokers and 587 smokers, of whom 572 had a known smoking index (SI). They were classified into mild, moderate and heavy smokers. Centrilobular emphysema (CLE), respiratory bronchiolitis, airspace enlargement with fibrosis (AEF), the presence of foci resembling usual interstitial pneumonia pattern (UIP/P) and the rate of postoperative respiratory failure were assessed. The incidence of AEF was 6.5% in mild smokers, and 17.7% in moderate smokers (P < 0.01) with lower lobe predominance. There were significant correlations (P < 0.01) between AEF and CLE and AEF and UIP/P. The rate of respiratory failure after lobectomy was 6%, and 10% in patients having UIP/P with or without AEF, but was not seen in patients with AEF alone (P < 0.01).

CONCLUSIONS

AEF is an important smoking-related change in the lung that appears to correlate with the smoking history, and its distinction from UIP/P may be important.

Novel ecological niche of Cetobacterium somerae, an anaerobic bacterium in the intestinal tracts of freshwater fish

AIMS

This study was conducted to clarify the taxonomic status of Bacteroides type A strains with high vitamin B(12)-producing ability that is widely distributed in the intestinal tracts of freshwater fish.

METHODS AND RESULTS

Seventeen strains of Bacteroides type A isolated from five fish species were all rod-shaped and gram-negative. The strains were positive for esculin hydrolysis, nitrate reduction, resistance to bile, acid phosphatase, and negative for the production of catalase and urease and the susceptibility to vancomycin. The G+C content of DNA from the 17 strains was 29 x 1-31 x 9 mol%, and 16S rDNA sequence analysis revealed a close phylogenetic relationship between Bacteroides type A strains and Cetobacterium somerae sharing 99 x 7-100% sequence similarity. In addition, strains were capable of producing vitamin B(12) at a rate of 1 x 82-13 x 98 ng ml(-1) in 48 h.

CONCLUSION

Phenotypic and phylogenetic characteristics indicated that all isolates previously classified as Bacteroides type A strains belong to C. someare.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided the important finding of novel niche of vancomycin-resistant bacteria such as C. somerae in the intestinal tract of freshwater fish.

Purification and characterization of Vibrio parahaemolyticus extracellular chitinase and chitin oligosaccharide deacetylase involved in the production of heterodisaccharide from chitin

A chitin-degrading bacterial strain, KN1699, isolated from Yatsu dry beach (Narashino, Chiba Prefecture, Japan), was identified as Vibrio parahaemolyticus. Treatment of powdered chitin with crude enzyme solution prepared from the supernatant of KN1699 cultures yielded a disaccharide, beta-D-N-acetylglucosaminyl-(1,4)-D-glucosamine (GlcNAc-GlcN), as the primary chitin degradation product. The extracellular enzymes involved in the production of this heterodisaccharide, chitinase (Pa-Chi; molecular mass, 92 kDa) and chitin oligosaccharide deacetylase (Pa-COD; molecular mass, 46 kDa), were isolated from the crude enzyme solution, and their hydrolysis specificities were elucidated. These studies confirmed that (1) Pa-Chi hydrolyzes chitin to produce (GlcNAc)(2) and (2) Pa-COD hydrolyzes the acetamide group of reducing end GlcNAc residue of (GlcNAc)(2). These findings indicate that GlcNAc-GlcN is produced from chitin by the cooperative hydrolytic reactions of both Pa-Chi and Pa-COD.

Immune modulation and expression of cytokine genes in rainbow trout Oncorhynchus mykiss upon probiotic feeding

This study elucidates the immune modulation including the expression of cytokine genes following dietary administration of three selected probiotic bacteria--Lactobacillus rhamnosus, Enterococcus faecium and Bacillus subtilis to fish, rainbow trout Oncorhynchus mykiss. They were fed for 45 days on either a basal control diet or one of the three probiotic diets containing the specific bacteria in freeze-dried form at a density of 10(9)CFUgfeed-1. The non-specific immune parameters examined--superoxide anion production by the head kidney leukocytes and the alternate complement activity of serum was improved by probiotic feeding. Besides this, the relative gene expressions of interleukin-1beta1, tumor necrosis factor 1 and 2 and transforming growth factor-beta were up regulated in the spleen and the head kidney. The comparatively better performance of E. faecium could possibly be linked to their suitable ambient temperature conditions. Thus, probiotic bacteria delivered in feed exerts its influence on the immune system of fish, both at cellular and molecular levels.

Identification of intestinal bacteria from Japanese flounder (Paralichthys olivaceus) and their ability to digest chitin

AIMS

The aim of the present study was to clarify the taxonomic status of intestinal bacteria isolated from Japanese flounder (Paralichthys olivaceus) and describe their ability to digest chitin.

METHODS AND RESULTS

Phylogenetic analysis based on 16S ribosomal DNA (rDNA) sequences showed that 82 representative isolates were closely related to three major species of marine vibrios, Vibrio scophthalmi-Vibrio ichthyoenteri group (41 isolates), Vibrio fischeri (39 isolates) and Vibrio harveyi (two isolates), with similarities of 97.2-99.8%, 96.4-100% and 98.6-99.5% respectively. These findings indicate that V. scophthalmi-V. ichthyoenteri group is indigenous to the intestinal tract of Japanese flounder. Moreover, the ability of 82 isolates to digest chitin was examined using the agar plate method and PCR amplification of the chiA gene. The two V. harveyi isolates and 36 of 41 V. scophthalmi-V. ichthyoenteri isolates digested chitin and were chiA PCR positive, whereas all 39 V. fischeri isolates digested chitin but were chiA PCR negative.

CONCLUSIONS

Intestinal bacteria from Japanese flounder were mainly composed of Vibrio scophthalmi-V. ichthyoenteri group and V. fischeri. Taken together, the results showed that 81 of 82 isolates could digest chitin. However, only 38 of these isolates possessed a chiA homologue which could be identified by PCR.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study shows that Japanese flounder harbours bacteria of the V. scophthalmi-V. ichthyoenteri group, and these results are similar to what has been found for turbot (Scophthalmus maximus).

Purification and characterization of chitinases from Clostridium sp. E-16 isolated from the intestinal tract of the South American sea lion (Otaria flavescens)

AIMS

This study was undertaken to examine the properties of chitinases purified from Clostridium sp. E-16, an intestinal bacterium of the South American sea lion (Otaria flavescens). We also elucidated the taxonomic status of this bacterium to better understand the role of intestinal anaerobic bacteria in marine animals.

METHODS AND RESULTS

Two chitinases were purified with ammonium sulfate precipitation, affinity chromatography and preparative electrophoresis from culture supernatant fluid from Clostridium sp. E-16. Molecular mass was estimated to be 77 kDa for chitinase 1 and 98 kDa for chitinase 2 by SDS-PAGE. Optimum pH of both purified chitinases was between 5.0 and 7.0. Chitinase 1 was inhibited with Cu(2+), Fe(2+), Hg(2+) and Zn(2+), while chitinase 2 was inhibited with Fe(2+). Phylogenetic analysis using 16S ribosomal DNA (rDNA) sequences and phenotypic characterization revealed that Clostridium sp. E-16 was closely related to Clostridium baratii.

CONCLUSIONS

It is likely that chitinases from C. baratii or a C. baratii-like bacterium play an important role in degradation of chitin in the intestinal tract of the South American sea lion and in marine environments.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of chitinase purification and characterization from a marine Clostridium strain.

Immune responses in rainbow trout Oncorhynchus mykiss induced by a potential probiotic bacteria Lactobacillus rhamnosus JCM 1136

This study was undertaken to examine the effect of supplementing a suggested probiotic bacteria Lactobacillus rhamnosus JCM 1136 in feed on immune response and gut flora composition of rainbow trout Oncorhynchus mykiss. The probiotic bacteria were incorporated into a commercial feed to constitute two experimental diets containing either 10(9) or 10(11) colony forming unit of live bacteria/g of feed while a third diet without the bacterial supplement served as the control diet. The diets were offered to rainbow trout (75g average weight) in triplicate tanks for 30 days. Fish were sampled at 10, 20 and 30 days after commencement of the feeding trial to determine the proportion of the given probiont in the gut microflora composition and the nonspecific humoral and cellular immune responses on the 30th day. The relative proportion of the probiont increased with the feeding duration in the intestine, but not in the stomach. The proportion of L. rhamnosus in the stomach corresponded to the intake levels while no such relation existed in the intestine. The serum lysozyme and complement activities were significantly greater in fish fed the higher level of probiont compared with the control fish. The phagocytic activity of head kidney leucocytes also showed similar tendencies. These observations indicate the potential immuno-regulatory role of probiotic organisms in rainbow trout.

Induced radioactivity in CU targets produced by high-energy heavy ions and the corresponding estimated photon dose rates

Irradiation experiments were performed at the Heavy Ion Medical Accelerator in Chiba (HIMAC) facility, National Institute of Radiological Sciences. The radioactive spallation products in a thick Cu target were obtained for Ar(230, 400 MeV per nucleon), Si(800 MeV per nucleon), Ne(100, 230, 400 MeV per nucleon), C(100, 230, 400 MeV per nucleon), He(100, 230 MeV per nucleon), p(100, 230 MeV) ions. The gamma-ray spectra from irradiated Cu samples inserted into the composite Cu target were measured with a high-purity germanium (HPGe) detector. From the gamma-ray spectra, we obtained the spatial distribution of radioactive yields of spallation products of 40 nuclides in the Cu sample in the Cu target. From the spatial distribution of radioactive yields, we estimated the residual activity and photon dose induced in the Cu target. The residual activity and photon dose become larger with the increase in projectile energy per nucleon and the range of the projectile beam for the same projectile energy per nucleon.

Clinical and immunohistochemical characteristics of benign giant cell tumour of bone with pulmonary metastases: case series

PURPOSE

Giant cell tumour of bone with pulmonary metastases is rare. However, some patients die of pulmonary metastases, and histological examination cannot distinguish between benign tumour and malignant metastases. In this study, we present clinical and immunohistochemical findings associated with giant cell tumour of bone with pulmonary metastases.

METHODS

Five patients with benign giant cell tumour of bone with pulmonary metastases (one man and 4 women) were studied. Patients' ages ranged between 20 and 23 years (mean age, 21.8 years). Tumours were in the distal femur in 2 cases, and in the proximal tibia, distal tibia, and lumbar spine in one case each. The tissue specimens from primary tumours, recurrent tumours, and pulmonary metastases were studied using immunohistochemical techniques.

RESULTS

Three of the 5 primary tumours were of the spontaneous regression or growth cessation type, or the continuously slow-growing type, showing 4.2% to 6.2% of positive cells for Ki-67 after immunohistochemical staining. However, 2 patients with the rapid-growing type of disease died of pulmonary metastases; their primary, recurrent, and metastatic tumour specimens contained 9.0% to 11.5% of positive cells for Ki-67.

CONCLUSION

Three of the 5 primary tumours had a benign clinical pattern and immunohistochemistry. Two of the 5 patients died of pulmonary metastases, which had an aggressive clinical pattern and a high prevalence of positive cells in Ki-67. Examination of Ki-67 should be carried out for aggressive type of giant cell tumour.

Surgical management of malignant soft tissue tumours in patients aged 65 years or older

OBJECTIVE

With the aim to determine the most effective treatment for primary malignant musculoskeletal tumours in patients aged 65 years or older, we reviewed cases of low- and high-grade neoplasms, surgical margins, surgical methods, and the prognoses of elderly and aged patients at our institution.

METHODS

Records of 25 patients aged 65 years or older who had malignant soft tissue tumours from December 1986 to February 1997 were reviewed. Low- and high-grade neoplasms accounted for 8 and 17 patients, respectively. 11 patients were aged 65 to 69 years, while 14 were 70 years or older. Surgical margins were wide in 19 cases, marginal in 4, and intralesional in 2. Reconstruction was done using 6 musculocutaneous flaps and/or 4 vessel grafts. As adjuvant therapy, radiotherapy was used in 5 cases and chemotherapy in 3. There was no recurrence in patients with wide surgical margins (determined on the basis of gross inspection of the excised tumour and the cut surface); but there was recurrence in 4 patients with marginal margins, and one patient with intralesional margin. Two patients with intralesional, 4 with marginal, and 2 with wide margins, died from recurrence at the primary site and metastasis, or from metastasis without recurrence at the primary site.

RESULTS

Follow-up periods ranged from 4 months to 180 months (mean, 91.6 months). The overall 5-year survival rate was 79.6%; for low- and high-grade neoplasms, the figures were 100% and 69.7%, respectively; for those aged 65 to 69 years and in their 70's or older, the figures were 90.9% and 70.1%, respectively.

CONCLUSION

For geriatric patients, wide surgical margins are required to manage both low- and high-grade neoplasms, in order to avoid multiple surgeries.

Genetic mutations in exons 3 and 4 of the pancreatic secretory trypsin inhibitor in patients with pancreatitis

PURPOSE

We hypothesized that mutations in the pancreatic secretory trypsin inhibitor (PSTI) gene could promote autodigestion, leading to acute or chronic pancreatitis. Our investigation involved mutation analysis of the PSTI gene in patients with acute or chronic pancreatitis.

METHODS

Mutation analysis for the PSTI gene was performed in patients with acute or chronic pancreatitis. Unrelated healthy volunteers and family members of a chronic pancreatitis patient with point mutations in the PSTI gene were also analyzed.

RESULTS

Two types of single-point mutation in the PSTI gene were observed in one patient with chronic pancreatitis: 34Asn (AAT)-to-Ser (AGT) (101 A > G N34S: N34S) in exon 3, and 67Arg (CGC)-to-Cys (TGC) (199 C > T R67C: R67C) in exon 4. No mutations with amino-acid substitution were found in other patients or in the volunteer group. In the patient with the PSTI gene mutations, no additional mutations were observed in the cationic trypsinogen gene. The family study revealed that the mother and a maternal uncle were homozygotes for the N34S mutation, while the father and brother were compound heterozygotes for the N34S and R67C mutations. The uncle (N34S/N34S) showed clinical manifestations of pancreatitis, but the other family members did not.

CONCLUSIONS

The N34S mutation may cause a predisposition to pancreatitis, with incomplete penetrance. However, with the limited information available, it is not known whether the R67C mutation promotes pancreatitis.

[A focal usual interstitial pneumonia lesion: an important risk factor in diffuse alveolar damage--acute exacerbation of a focal usual interstitial pneumonia patient]

The aim of this study was to clarify whether the presence of a focal usual interstitial pneumonia lesion (F-UIP) is a risk factor for diffuse alveolar damage (DAD). Our subjects were 977 patients (681 males, 296 females, mean age, 64 years). The incidence of F-UIP increased significantly with age (between 50 and 60 years, 3% and 8%, p < 0.05; between 60 and 70 years, 8% and 14.1%, p < 0.05; and between 70 and 80 years, 14.1% and 27.9%, p < 0.01). The mean age of the non-UIP group was 64 years, and of the F-UIP group was 75 years, showing significance (p < 0.001). The incidence of DAD was higher in the F-UIP group (100 patients, 30%, p < 0.01) and the diffuse UIP group (60 patients, 30%, p < 0.01) than in the non-UIP group (817 patients, 5.3%). Although the causes of DAD were various, the presence of F-UIP was a important risk factor of DAD.

Photorearrangement of vinylidenecyclopropanes to 1,2,3-butatriene derivatives

[reaction: see text] Photoirradiation of benzene solutions containing 1-diarylvinylidene-2,2,3,3-tetramethylcyclopropanes (2a--d) afforded rearranged products 1,2,3-butatrienes (3a-d) in good to high yields. Photorearrangement from 2,2,3-trimethyl and 2,2- and 2,3-dimethyl derivatives 2e--g also proceeded, but the rates of the rearrangement were lower than those of 2a--d. A singlet mechanism is proposed for this photorearrangement, where alkyl migration occurs from 1,3-biradical intermediates generated via the homolysis of the C1-C2 bond. Generation of diarylvinylidene carbenes from 1,3-biradicals might be competitive with the formation of 3.

[Prognosis of subacutely progressive interstitial pneumonia depends on the presence of focal usual interstitial pneumonia]

A retrospective follow-up study was conducted on patients with subacutely progressive interstitial pneumonia who underwent surgical biopsy. Pathologically, they were subclassified into subacute interstitial pneumonia (SIP) and SIP + F, which consisted of an SIP lesion and a focal usual interstitial pneumonia. The SIP group consisted of 35 cases and the SIP + F group, of 15 cases. The majority of patients in both groups were female and complained of dyspnea. Both groups showed increased neutrophil counts (8.8%, 6.3%), eosinophils (6%, 5.6%), and lymphocytes (43.1%, 42.3%) in bronchoalveolar lavage. Chest radiography generally demonstrated predominant lower lobe involvement together with shrinkage in both groups, and differentiation of the two was difficult before biopsy. All but one improved temporarily with steroid therapy, or spontaneously, in both groups. On further observation after temporary improvement, 27 cases (82%), did not show any worsening and 6 cases (18%) showed worsening (including death) in the SIP group, while 6 cases (43%) showed no worsening, though 8 cases (57%) worsened in the SIP + F group. Deaths in either group that were not related to the original diseases were excluded from the statistical analysis. We concluded that the presence of focal usual interstitial pneumonia in SIP lesions affects prognosis in patients with subacutely progressive interstitial pneumonia.

Long-term denervation impairs insulin receptor substrate-1-mediated insulin signaling in skeletal muscle

Long-term denervation is associated with insulin resistance. To investigate the molecular bases of insulin resistance, the downstream signaling molecules of insulin receptor including insulin receptor substrate-1 (IRS-1) and phosphatidylinositol 3-kinase (PI 3-K) were examined in skeletal muscle of rats after 7 days of denervation. Long-term denervation attenuated insulin-stimulated activation of the initial steps of the intracellular signaling pathway. Insulin-stimulated tyrosine phosphorylation of insulin receptor was reduced to 36% (P < .005), as was the phosphorylation of IRS-1 to 34% (P < .0001) of control. While insulin receptor protein level was unchanged, the protein expression of IRS-1 was significantly decreased in denervated muscles. Insulin-stimulated percent tyrosine phosphorylation of IRS-1, normalized to the IRS-1 protein expression, was also reduced to 55% (P < .01) of control in denervated muscle. Denervation caused a decline in the insulin-induced binding of p85 regulatory subunit of PI 3-K to IRS-1 to 61% (P < .001) and IRS-1-associated PI 3-K activity to 57% (P < .01). These results provide evidence that long-term denervation results in insulin resistance because of derangements at multiple points, including tyrosine phosphorylation of insulin receptor and its downstream signaling molecule, IRS-1, protein expression of IRS-1, and activation of PI 3-K.

Three cases of cat scratch disease diagnosed by indirect immunofluorescence antibody assay and/or polymerase chain reaction of 16S rRNA gene of Bartonella henselae

Three suspected cases of cat scratch disease were diagnosed by indirect immunofluorescence antibody assay and/or polymerase chain reaction. Patient 1 was a 10-year-old female who presented swelling of the right axillary [corrected] lymph nodes with pain and fever. She kept a kitten, and many scratches were observed on her both legs and dorsum manus. Antibody titers against Bartonella (B.) henselae were 1:32 for IgM 3 weeks after the onset of the symptoms and 1:64 for IgG 8 weeks after the onset. The DNA for 16S rRNA type I of B. henselae was detected from the blood sample obtained 3 weeks after the onset of symptoms by polymerase chain reaction for the first time in Japan. Patient 2 was a 22-year-old female veterinary student with a cat scratch at the bottom of her neck by a male kitten. She developed a papule at the scratch, slight fever, and neck pain. Although both Bartonella-specific IgG and IgM antibodies were negative before the scratch, the IgG antibody titer rose to 1:512 14 weeks after the onset. B. henselae was isolated from the kitten and its DNA found to be for 16S rRNA type I by PCR. Patient 3 was a 23-year-old female veterinary student with a cat scratch on her left forearm. A small reddish papule developed on the scratch, and she experienced swelling of the left axillary [corrected] lymph node and pain. Both the IgG and IgM antibodies against B. henselae were negative before the cat scratch, and the IgG titer rose significantly to 1:128 and 1:1,024 in 2 and 5 weeks, respectively, after the onset of the symptoms.

Immobilization depresses insulin signaling in skeletal muscle

Prolonged immobilization depresses insulin-induced glucose transport in skeletal muscle and leads to a catabolic state in the affected areas, with resultant muscle wasting. To elucidate the altered intracellular mechanisms involved in the insulin resistance, we examined insulin-stimulated tyrosine phosphorylation of the insulin receptor beta-subunit (IR-beta) and insulin receptor substrate (IRS)-1 and activation of its further downstream molecule, phosphatidylinositol 3-kinase (PI 3-K), after unilateral hindlimb immobilization in the rat. The contralateral hindlimb served as control. After 7 days of immobilization of the rat, insulin was injected into the portal vein, and tibialis anterior muscles on both sides were extracted. Immobilization reduced insulin-stimulated tyrosine phosphorylation of IR-beta and IRS-1. Insulin-stimulated binding of IRS-1 to p85, the regulatory subunit of PI 3-K, and IRS-1-associated PI 3-K activity were also decreased in the immobilized hindlimb. Although IR-beta and p85 protein levels were unchanged, IRS-1 protein expression was downregulated by immobilization. Thus prolonged immobilization may cause depression of insulin-stimulated glucose transport in skeletal muscle by altering insulin action at multiple points, including the tyrosine phosphorylation, protein expression, and activation of essential components of insulin signaling pathways.