Strain-Specific Anti-Inflammatory Effects of Faecalibacterium prausnitzii Strain KBL1027 in Koreans

Faecalibacterium prausnitzii is one of the most dominant commensal bacteria in the human gut, and certain anti-inflammatory functions have been attributed to a single microbial anti-inflammatory molecule (MAM). Simultaneously, substantial diversity among F. prausnitzii strains is acknowledged, emphasizing the need for strain-level functional studies aimed at developing innovative probiotics. Here, two distinct F. prausnitzii strains, KBL1026 and KBL1027, were isolated from Korean donors, exhibiting notable differences in the relative abundance of F. prausnitzii. Both strains were identified as the core Faecalibacterium amplicon sequence variant (ASV) within the healthy Korean cohort, and their MAM sequences showed a high similarity of 98.6%. However, when a single strain was introduced to mice with dextran sulfate sodium (DSS)-induced colitis, KBL1027 showed the most significant ameliorative effects, including alleviation of colonic inflammation and restoration of gut microbial dysbiosis. Moreover, the supernatant from KBL1027 elevated the secretion of IL-10 cytokine more than that of KBL1026 in mouse bone marrow-derived macrophage (BMDM) cells, suggesting that the strain-specific, anti-inflammatory efficacy of KBL1027 might involve effector compounds other than MAM. Through analysis of the Faecalibacterium pan-genome and comparative genomics, strain-specific functions related to extracellular polysaccharide biosynthesis were identified in KBL1027, which could contribute to the observed morphological disparities. Collectively, our findings highlight the strain-specific, anti-inflammatory functions of F. prausnitzii, even within the same core ASV, emphasizing the influence of their human origin.

Small Bowel Variceal Bleeding in Patients with Liver Cirrhosis Treated with Transarterial Embolization: Case Series

Small bowel variceal bleeding is a rare cause of gastrointestinal hemorrhage, with clinical manifestations ranging from asymptomatic incidental findings to life-threatening conditions. The diagnosis and management of small bowel bleeding are challenging because of the localization of the lesion and the difficulty of the procedure. Trans-arterial embolization (TAE) is a secure and straightforward method for treating ectopic varices. On the other hand, there have been limited local studies on the outcomes of TAE for patients with small bowel variceal hemorrhage. This paper reports patients diagnosed with small bowel variceal bleeding and treated with TAE.

Potential application of immunotherapy for modulation of pulp inflammation: opportunities for vital pulp treatment

Caries results in the demineralization and destruction of enamel and dentine, and as the disease progresses, irreversible pulpitis can occur. Vital pulp therapy (VPT) is directed towards pulp preservation and the prevention of the progression of inflammation. The outcomes of VPT are not always predictable, and there is often a poor correlation between clinical signs and symptoms, and the events occurring at a molecular level. The inflamed pulp expresses increased levels of cytokines, including tumour necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-4, IL-6, IL-8, IL-17 and IL-23, which recruit and drive a complex cellular immune response. Chronic inflammation and sustained cytokine release can result in irreversible pulp damage and a decreased capacity for tissue healing. Other chronic inflammatory diseases, such as psoriasis, inflammatory bowel diseases and rheumatoid arthritis, are also characterized by an dysregulated immune response composed of relatively high cytokine levels and increased numbers of immune cells along with microbial and hard-soft tissue destructive pathologies. Whilst anti-cytokine therapies have been successfully applied in the treatment of these diseases, this approach is yet to be attempted in cases of pulp inflammation. This review therefore focuses on the similarities in the aetiology between chronic inflammatory diseases and pulpitis, and explores how anti-cytokine therapies could be applied to manage an inflamed pulp and facilitate healing. Further proof-of-concept studies and clinical trials are justified to determine the effectiveness of these treatments to enable more predictable outcomes in VPT.

Clostridium fessum sp. nov., isolated from human faeces

An obligately anaerobic, Gram-stain-positive and spore-forming strain, SNUG30386^T was isolated from a faecal sample of a healthy Korean subject. The strain formed a round ivory-coloured colony and cells were chained rods with tapered ends, approximately 2.0-2.5×0.6-0.8 μm in size. The taxonomic analysis indicated that strain SNUG30386^T was within the family Lachnospiraceae. According to the 16S rRNA gene sequence similarity, the closest species to strain SNUG30386^T was Clostridium symbiosum (95.6 %), followed by Enterocloster asparagiformis (94.8 %), Enterocloster clostridioformis (94.8 %) and Enterocloster lavalensis (94.6 %). The evolutionary tree based on 16S rRNA gene sequences demonstrated that strain SNUG30386^T had split apart at a unique branch point far from other close relatives. Its DNA G+C content was 48.3 mol% calculated from the whole genome sequence. The major cellular fatty acids were C_16 : 0 and C_14 : 0. Compared to those of the closely related species, strain SNUG30386^T showed distinct biochemical activities such as being unable to utilize most of carbon sources except d-glucose and l-arabinose. As a result, based on its unique phylogenetic clade and taxonomic characteristics, we conclude that strain SNUG30386^T represents a novel species within the genus Clostridium, for which the name Clostridium fessum sp. nov. is proposed. The type strain of the novel species is SNUG30386^T (=KCTC 15633^T= JCM 32258^T).

Administration of Lactobacillus fermentum KBL375 Causes Taxonomic and Functional Changes in Gut Microbiota Leading to Improvement of Atopic Dermatitis

Gut microbiota play an important role in immune responses and energy metabolism. In this study, we evaluated whether administration of Lactobacillus fermentum (L. fermentum) KBL375 isolated from healthy Korean feces improves the atopic dermatitis using the house dust mite (Dermatophagoides farinae)-induced atopic dermatitis (AD) mouse model. Administration of L. fermentum KBL375 significantly decreased dermatitis score, ear and dorsal thickness, and serum immunoglobulin E level in AD-induced mice. Significant reductions in mast cells and eosinophils were discovered in skin tissues from L. fermentum KBL375-treated mice. T helper 2 cell-related cytokines interleukin (IL)-4, IL-5, IL-13, and IL-31 significantly decreased, and anti-inflammatory cytokine IL-10 or transforming growth factor-β increased in skin tissues from L. fermentum KBL375-treated mice. In addition to phenotypic changes in skin tissues, L. fermentum KBL375 treatment induced an increase in the CD4+CD25+Foxp3+ cell population in mesenteric lymph nodes. Taxonomic and functional analyses of gut microbiota showed significantly higher cecum bacterial diversities and abundances including genus Bilophila, Dorea, and Dehalobacterium in L. fermentum KBL375-treated mice. Metabolic analysis of the cecum also showed significant changes in the levels of various amino acids including methionine, phenylalanine, serine, and tyrosine, as well as short chain fatty acids such as acetate, butyrate, and propionate in AD-induced mice due to L. fermentum KBL375 treatment. These altered metabolites in AD-induced mice returned to the levels similar to those in control mice when treated with L. fermentum KBL375. Therefore, L. fermentum KBL375 could be useful for AD treatment by modulating the immune system and inducing various metabolites.

Faecalibacillus intestinalis gen. nov., sp. nov. and Faecalibacillus faecis sp. nov., isolated from human faeces

Two long-rod-shaped, Gram-stain-positive, obligately anaerobic and non-spore-forming strains, SNUG30099^T and SNUG30370^T, were isolated from faecal samples of healthy Korean subjects. The strains formed circular ivory-coloured colonies on Brain-heart infusion medium supplemented with 0.5% Difco yeast extract (YBHI) agar and cells were approximately 3.5-4.5×0.3-0.4 µm in size. Taxonomic analyses based on 16S rRNA gene sequences distinguished the strains from other species within the family Erysipelotrichaceae. The closest relative of strains SNUG30099^T and SNUG30370^T was Longibaculum muris (92.9 % and 93.6 % similarity, respectively), followed by Clostridium saccharogumia (92.3 % and 92.2 %). Phylogenetic inference also divided the strains into a unique branch that differed from other related strains that belong to the family Erysipelotrichaceae. DNA G+C contents based on the whole genome sequences of strains SNUG30099^T and SNUG30370^T were 29.2 and 30.2 mol%, respectively. Both novel strains possessed meso-diaminopimelic acid as the peptidoglycan, and phosphatidylethanolamine was observed as one of the major polar lipids. The major cellular fatty acid composition was different from those of other related taxa. In addition, the profile of biochemical activities advocated that the strains have distinct characteristics in comparison to other strains. Taken together, a novel genus, named Faecalibacillus gen. nov., is proposed, which includes the type species Faecalibacillus intestinalis sp. nov. for strain SNUG30099^T and Faecalibacillus faecis sp. nov. for strain SNUG30370^T. The type strains of these novel species are SNUG30099^T (=KCTC 15631^T=JCM 32256^T) and SNUG30370^T (=KCTC 15632^T=JCM 32257^T).

Human papillomavirus and oral and oropharyngeal carcinoma: the essentials

There is a global increase in the prevalence of human papillomavirus (HPV)-driven oropharyngeal squamous cell carcinoma (OPSCC) in Australia and New Zealand. Risk factors for HPV-positive OPSCC are male gender, white race, age older than 40 but younger than 59 years old, having multiple lifetime sex partners, having oro-genital and oro-anal sex. High-risk HPV subtypes play a major role in the pathogenesis of OPSCC, however, they play a much lesser role in oral squamous cell carcinoma (OSCC). Among the laboratory tests used to detect oncogenic HPV infection, polymerase chain reaction is a sensitive method but does not reflect the role of HPV in oncogenesis. While widely used, p16 immunohistochemistry is both a sensitive and a specific surrogate marker for oncogenic HPV infection in OPSCC, but not in OSCC. However, it is a useful prognostic marker in OPSCC. The current gold standard to accurately detect oncogenic HPV infection is E6/E7 mRNAin situ hybridization. Because both HPV-positive and p16-positive OPSCC have better short-term prognoses there is current debate and trials on treatment de-escalation in HPV-positive OPSCC. Dental practitioners can play an important role in early diagnosis of HPV-positive OPSCC.

Incidence of cephalosporin-induced anaphylaxis and clinical efficacy of screening intradermal tests with cephalosporins: A large multicenter retrospective cohort study

BACKGROUND

Few studies have investigated the incidence of anaphylaxis induced by individual or structurally similar cephalosporins. The aims of the study were to assess the incidence of cephalosporin-induced anaphylaxis and evaluate the clinical efficacy of screening skin tests.

METHODS

In this retrospective cohort study, we obtained information on total cephalosporin use and cephalosporin-induced anaphylaxis in intravenous cephalosporin recipients in 12 general hospitals between 2013 and 2015. Cephalosporins were divided into 4 groups according to similar side-chain structures. The incidence of cephalosporin-induced anaphylaxis was assessed for each cephalosporin, cephalosporin generation, and side-chain group. To verify the efficacy of screening intradermal tests (IDT) with cephalosporin, the 12 hospitals were assigned to the intervention or control group depending on whether they performed screening IDT before the administration of cephalosporins.

RESULTS

We identified 76 cases of cephalosporin-induced anaphylaxis with 1 123 345 exposures to intravenous cephalosporins (6.8 per 100 000 exposures), and the incidence of fatal anaphylaxis by cephalosporin was 0.1 cases per 100 000 exposures. The highest incidences of anaphylaxis occurred in the ceftizoxime (13.0 cases per 100 000 exposures) and side-chain group 1 (cefepime, cefotaxime, ceftizoxime, ceftriaxone, and cefuroxime; 9.3 per 100 000). There was no case of anaphylaxis induced by cefoxitin, cefmetazole, cefminox, and cefotiam. The clinical effectiveness of routine screening IDT was not significant (P = .06).

CONCLUSIONS

The incidence of cephalosporin-induced anaphylaxis differed according to individual drugs and side-chain structure. Screening IDT showed no clinical efficacy at a population level.

Synthesis of Bicyclic Isothiazoles through an Intramolecular Rhodium-Catalyzed Transannulation of Cyanothiadiazoles

An intramolecular rhodium-catalyzed transannulation of readily available cyanothiadiazoles containing an ester, amide, or ether as a linker is described. It provides a wide range of bicyclic isothiazoles in good to excellent yields together with the release of molecular nitrogen. These results indicate that the carbon atom in the α-thiavinyl carbene is nucleophilic and that the sulfur atom is electrophilic.

Synthesis of Imidazopyridines via Copper-Catalyzed, Formal Aza-[3 + 2] Cycloaddition Reaction of Pyridine Derivatives with α-Diazo Oxime Ethers

The Cu-catalyzed, formal aza-[3 + 2] cycloaddition reaction of pyridine derivatives with α-diazo oxime ethers in trifluoroethanol was used to synthesize imidazopyridines via the release of molecular nitrogen and elimination of alcohol. These methods enabled modular synthesis of a wide range of N-heterobicyclic compounds such as imidazopyridazines, imidazopyrimidines, and imidazopyrazines with an α-imino Cu-carbenoid generated from the α-diazo oxime ethers and copper.

Burkholderia megalochromosomata sp. nov., isolated from grassland soil

A Gram-stain negative, rod-shaped, non-spore-forming, obligate aerobic bacterial strain, JC2949T, was isolated from grassland soil in Gwanak Mountain, Seoul, Republic of Korea. Phylogenetic analysis, based on 16S rRNA sequences, indicated that strain JC2949T belongs to the genus Burkholderia , showing highest sequence similarities with Burkholderia grimmiae R27T (98.8 %), Burkholderia cordobensis LMG 27620T (98.6 %), Burkholderia jiangsuensis MP-1TT (98.6 %), Burkholderia zhejiangensis OP-1T (98.5 %), Burkholderia humi LMG 22934T (97.5 %), Burkholderia terrestris LMG 22937T (97.3 %), Burkholderia telluris LMG 22936T (97.2 %) and Burkholderia glathei ATCC 29195T (97.0 %). The major fatty acids of strain JC2949T were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. Its predominant polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and an unknown amino phospholipid. The dominant isoprenoid quinone was ubiquinone Q-8. The pairwise average nucleotide identity values between strain JC2949T and the genomes of 30 other species of the genus Burkholderia ranged from 73.4–90.4 %, indicating that the isolate is a novel genomic species within this genus. Based on phenotypic and chemotaxonomic comparisons, it is clear that strain JC2949T represents a novel species of the genus Burkholderia . We propose the name for this novel species to be Burkholderia megalochromosomata sp. nov. The type strain is JC2949T ( = KACC 17925T = JCM 19905T).

Burkholderia monticola sp. nov., isolated from mountain soil

An ivory/yellow, Gram-stain-negative, short-rod-shaped, aerobic bacterial strain, designated JC2948T, was isolated from a soil sample taken from Gwanak Mountain, Republic of Korea. 16S rRNA gene sequence analysis indicated that strain JC2948T belongs to the genus Burkholderia . The test strain showed highest sequence similarities to Burkholderia tropica LMG 22274T (97.6 %), Burkholderia acidipaludis NBRC 101816T (97.5 %), Burkholderia tuberum LMG 21444T (97.5 %), Burkholderia sprentiae LMG 27175T (97.4 %), Burkholderia terricola LMG 20594T (97.3 %) and Burkholderia diazotrophica LMG 26031T (97.1 %). Based on average nucleotide identity (ANI) values, the new isolate represents a novel genomic species as it shows less than 90 % ANI values with other closely related species. Also, other phylosiological and biochemical comparisons allowed the phenotypic differentiation of strain JC2948T from other members of the genus Burkholderia . Therefore, we suggest that this strain should be classified as the type strain of a novel species of the genus Burkholderia . The name Burkholderia monticola sp. nov. (type strain, JC2948T = JCM 19904T = KACC 17924T) is proposed.

Synthesis of pyrroles from terminal alkynes, N-sulfonyl azides, and alkenyl alkyl ethers through 1-sulfonyl-1,2,3-triazoles

A method for synthesis of substituted pyrroles has been developed. 1-Sulfonyl-1,2,3-triazoles generated from terminal alkynes gave α-imino rhodium carbene complexes, which when reacted with alkenyl alkyl ethers afforded substituted pyrroles. The method can be efficiently applied to a one-pot sequential reaction starting from terminal alkynes.

Fretibacter rubidus gen. nov., sp. nov., isolated from seawater

A brick-red-coloured, curved-rod-shaped, prostheca-bearing and non-motile bacterial strain, designated JC2236T, was isolated from a seawater sample of Jeju Island, Republic of Korea. 16S rRNA gene sequence analysis indicated that this strain belongs to the family Hyphomonadaceae and represents a distinct phyletic line that reflects a novel genus status within a clade containing the genera Litorimonas , Hellea , Robiginitomaculum and Algimonas . The predominant isoprenoid quinone (Q10) and polar lipid profile (phosphatidylglycerol, glucuronopyranosyl diglyceride and monoglycosyl diglyderide) were in line with those of most members of the family. However, the DNA G+C content (49.3 mol%), the abundance of C16 : 0, the requirement of sea salts for growth and absence of cell motility differentiated strain JC2236T from other closely related genera. Overall enzyme traits also demonstrated that the novel strain is not closely affiliated with any of the previously described genera. Thus, based on data from the present polyphasic taxonomic study, strain JC2236T is considered to represent a novel species of a new genus belonging to the family Hyphomonadaceae , for which the name Fretibacter rubidus gen. nov., sp. nov. is proposed. The type strain of Fretibacter rubidus is JC2236T ( = KACC 16935T = JCM 15585T).

Differential expression of forkhead box M1 and its downstream cyclin-dependent kinase inhibitors p27(kip1) and p21(waf1/cip1) in the diagnosis of pulmonary neuroendocrine tumours

AIMS

Pulmonary neuroendocrine (NE) tumours represent a spectrum of phenotypically distinct entities with different biological behaviours. Difficulties in classifying these tumours are frequently encountered in clinical practice. Forkhead box M1 (FoxM1) is essential for the development of various cancers and is a proliferation-specific transcription factor that regulates transcription of cell cycle genes, including cyclin-dependent kinase inhibitors p27(kip1) and p21(waf1/cip1) . This study was performed to determine the utility of FoxM1, p27(kip1) and p21(waf1/cip1) as immunomarkers for subtyping pulmonary NE tumours.

METHODS AND RESULTS

FoxM1, p27(kip1) and p21(waf1/cip1) expression was evaluated by immunohistochemistry in 60 pulmonary NE tumours [19 typical carcinoids (TCs), six atypical carcinoids (ACs), 17 large cell neuroendocrine carcinomas (LCNECs) and 18 small cell lung cancers (SCLCs)]. The frequencies of FoxM1 and p21(waf1/cip1) expression were significantly different between TCs and ACs (each P = 0.009), and those of FoxM1 and p27(kip1) expression were significantly different between LCNECs and SCLCs (P = 0.012 and P = 0.002, respectively). The combined FoxM1((-)) /p21(waf1/cip1(-)) and FoxM1((+)) /p27(kip1(high)) phenotypes had the best diagnostic accuracy for distinguishing TCs from ACs, and SCLCs from LCNECs, respectively.

CONCLUSIONS

FoxM1, p27(kip1) and p21(waf1/cip1) showed distinct immunoreactivity according to histological subtype, which may be of value as an ancillary test in the differential diagnosis of pulmonary NE tumours.

Comprehensive analysis of Excision repair complementation group 1, Glutathione S-transferase, Thymidylate synthase, and Uridine diphosphate glucuronosyltransferase 1A1 polymorphisms predictive for treatment outcome in patients with advanced gastric cancer treated with FOLFOX or FOLFIRI

e15580

Background: Pharmacogenetic advances in cancer chemotherapy have the potential to predict clinical benefit to particular regimens. Oxaliplatin and irinotecan have shown to be effective in the treatment of gastric cancer. We assessed whether single nucleotide polymorphisms (SNPs) in ERCC1, GST, TS, and UGT1A1predicted overall survival in gastric cancer patients receiving FOLFOX and/or FOLFIRI chemotherapy. Methods: Total genomic DNA was extracted from whole blood of patient. The PCR- restriction fragment length polymorphism (RFLP) method was applied to detect the known variant sites of ERCC1, GST, TS, and UGT1A1. Results: Response rate of FOLFOX (N=75) was 24%. Grade 3–4 neutropenia and neurotoxicity were observed 34.7% and 16%, respectively. TTP and OS of 1st line administration of FOLFOX (N=35) was 3.1 months (95% CI, 0.1–6.1 months) and 13.9 months (95% CI, 12.2–15.6 months). Only the GSTM1 positive genotype showed a significantly better time to progression (P=0.023). But significant genotype variation of TS, GST and ERCC1,which assumed to affect to activity of oxaliplatin was not observed to RR, toxicity, and overall survival. Response rate of FOLFIRI (N=74) was 23%. Grade 3–4 neutropenia and diarrhea were observed 55.4% and 9.5%, respectively. TTP and OS of 1st line administration of FOLFIRI (N=33) was 4.9 months (95% CI, 3.5–6.4 months) and 19.0 months (95% CI, 8.5–29.5months). Low expression type (2R/2R, 2R/3C, and 3C/3C) of TS was associated with high incidence of grade ≥3 neutropenia. But significant genotype variation of UGT1A1,which assumed to affect to toxicity of irinotecan was not observed to RR, toxicity, and survival. Conclusions: In this study, GSTM1 positive genotype showed a significantly better time to progression in the advanced gastric cancer treated with FOLFOX. Low expression type (2R/2R, 2R/3C, and 3C/3C) of TS was associated with high incidence of grade ≥3 neutropenia in the advanced gastric cancer treated with FOLFIRI. Well designed prospective trial will be clearly identifying relations between chemotherapy and genetic variations.

No significant financial relationships to disclose.

Apocrine carcinoma of the breast: clinical presentations, multimodality imaging findings and pathologic correlation

Abstract #4029

Background : 
 Apocrine carcinoma (AC) of the breast is a rare malignant tumor and is lack of standardized criteria for the diagnosis. Thus clinicopathological features and radiologic findings have not been determined. We retrospectively analyzed the clinical presentation and the multimodality imaging findings of mammography, ultrasography and MRI and correlated with pathologic results.
 Materials and Methods : 
 We retrospectively examined data on 850 patients who had been surgically treated for primary breast carcinoma between 2003 and 2008. Among them, there were 10 cases with the diagnosis of apocrine carcinoma.
 Ten patients underwent mammography and ultrasonography and six patients underwent MR imaging. Eight patients underwent pre-operative US-guided core needle biopsy. We analyzed the radiologic findings and pathologic results.
 Results : 
 The present study showed that the frequency of apocrine carcinoma was 1.2%. Almost all patients were symptomatic and painless lump was the most common complaint. Patient ranged in age from 38 to 62 year (mean, 50.5 years). The mean lesion size was 1.9cm (range, 1.1-3.5cm).
 Common imaging features were as follows: mass or focal asymmetry without microcalcifications (n=7), mass with microcalcifications (n=3) on mammography; a mass with an round to irregular shape (n=9), indistinct-margin(n=8) on ultrasonography. On six dynamic contrast-enhanced MRI, enhancing masses in 3, mass with spotty nodular enhancement adjacent to the tumor in 3, which showed rapid enhancement and delayed washout pattern in five cases and plateau enhancement pattern in one case. Specifically, 3 patients had unilateral multifocal cancer. Two patients showed ipsilateral axillary lymphadenopathy.
 Pathologic examination revealed AC (n=3), AC with apocrine carcinoma in situ (n=3), apocrine carcinoma in situ (n=1) and, AC with intraductal component and EIC positivity (n=3). Mass with spotty nodular enhancement on MRI was correlated with intraductal component and EIC positivity.
 Conclusion : 
 The radiologic findings of apocrine carcinoma of the breast are not specific. Occasionally, apocrine carcinoma shows mass with spotty nodular enhancement adjacent to the tumor on MRI and this finding is correlated with intraductal component and EIC positivity.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4029.

Estrogen affects vascular tone differently according to vasoactive substances in ovariectomized Sprague-Dawley rat

The favorable effects of estrogen on cardiovascular diseases can be explained by several mechanisms such as changes in serum lipid profiles and thrombogenecity. Estrogen also affects the vascular tone, but there has been no report in which the effect of estrogen was tested comprehensively for several vasoactive substances, especially after long-term administration. Two weeks after bilateral ovariectomy in 8-week old female Sprague-Dawley rats, placebo or 17 beta-estradiol (E2) pellets (0.5 mg; released over 3 weeks) were implanted subcutaneously. Two weeks after pellet implantation, organ chamber experiments were performed using aortae. Compared with control, E2-treated vessels showed impaired endothelium-dependent relaxation to acetylcholine. E2 enhanced the contraction to norepinephrine and U46619 and had no effect on endothelin-1-induced contraction. In contrast, the contraction to angiotensin (AT)-II was inhibited by E2. Northern blot analysis for AT1 receptor expression using cultured aortic smooth muscle cells showed no difference between control and E2-treated cells, suggesting that AT1 receptor downregulation is not the likely mechanism. These results suggest that E2 affects the vascular tone variably according to vasoactive substances.

Pasteurella multocida toxin stimulates mitogen-activated protein kinase via G(q/11)-dependent transactivation of the epidermal growth factor receptor

The dermatonecrotic toxin produced by Pasteurella multocida is one of the most potent mitogenic substances known for fibroblasts in vitro. Exposure to recombinant P. multocida toxin (rPMT) causes phospholipase C-mediated hydrolysis of inositol phospholipids, calcium mobilization, and activation of protein kinase C via a poorly characterized mechanism involving G(q/11) family heterotrimeric G proteins. To determine whether the regulation of G protein pathways contributes to the mitogenic effects of rPMT, we have examined the mechanism whereby rPMT stimulates the Erk mitogen-activated protein kinase cascade in cultured HEK-293 cells. Treatment with rPMT resulted in a dose and time-dependent increase in Erk 1/2 phosphorylation that paralleled its stimulation of inositol phospholipid hydrolysis. Both rPMT- and alpha-thrombin receptor- stimulated Erk phosphorylation were selectively blocked by cellular expression of two peptide inhibitors of G(q/11) signaling, the dominant negative mutant G protein-coupled receptor kinase, GRK2(K220R), and the Galpha(q) carboxyl-terminal peptide, Galpha(q)-(305-359). Like alpha-thrombin receptor-mediated Erk activation, the effect of rPMT was insensitive to the protein kinase C inhibitor GF109203X, but was blocked by the epidermal growth factor receptor-specific tyrphostin, AG1478 and by dominant negative mutants of mSos1 and Ha-Ras. These data indicate that rPMT employs G(q/11) family heterotrimeric G proteins to induce Ras-dependent Erk activation via protein kinase C-independent "transactivation" of the epidermal growth factor receptor.

Barbarin as a new tyrosinase inhibitor from Barbarea orthocerus

A tyrosinase inhibitor was isolated from the whole plant of Barbarea orthocerus Led. (Brassicaceae) by activity-guided fractionation, and identified as (R)-5-phenyl-2-oxazolidinethione (barbarin) by structural analysis followed by comparison with reported spectral data. The compound exhibited significant inhibitory effects on mushroom and murine tyrosinases at more than 1.6 x 10(-5) M. Barbarin exhibited IC50 values of 4.2 x 10(-5) M on mushroom tyrosinase and of 4.8 x 10(-5) M on murine tyrosinase. Kojic acid as a positive control exhibited IC50 values of 3.4 x 10(-5) M and 6.0 x 10(-5) M on mushroom and murine tyrosinases, respectively. Therefore, barbarin exhibited a similar level of inhibitory potency with kojic acid used as a positive control. In a kinetic study with various concentrations of L-dopa as the substrate, barbarin was identified as an uncompetitive inhibitor and kojic acid as a mixed inhibitor of both mushroom and murine tyrosinases. Barbarin exhibited KEIS values of 3.3 x 10(-5) M and 3.6 x 10(-5) M on mushroom and murine tyrosinases, respectively. Kojic acid exhibited KEIS and KEI values of 2.4 x 10(-5) M and 2.2 x 10(-5) M on mushroom tyrosinase and those of 8.9 x 10(-5) M and 7.2 x 10(-5) M on murine tyrosinase, respectively.

Toluene distribution of glue sniffers' biological fluid samples in Korea

We have studied the distribution of toluene in glue sniffers' biological fluid samples by gas chromatography or gas chromatography/mass spectrometry. The determined toluene concentrations ranged from 0.1 to 40.3 mg/L in urine samples and from 0.1 to 74.7 mg/L in blood samples, respectively. Among the 120 urine samples, 61% of all cases ranged between 0.1 and 1.0 mg/L and 27% was between 1.0 and 5.0 mg/L, respectively. On the other hand, 39% and 46% of all 99 blood samples ranged between 0.1 and 1.0 mg/L, or 1.0 and 5.0 mg/L, respectively. In the fatal cases (36 cases), the distribution of toluene ranged from 0.3 to 40.5 mg/L in the blood samples.

ETA and ETB receptors mediate contraction to endothelin-1 in renal artery of aging SHR. Effects of FR139317 and bosentan

We characterized vascular endothelin receptors of the renal artery from adult (12 to 16 weeks of age) and old (72 to 76 weeks) spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY). Vessels were suspended in organ chambers (37 degrees C, aerated with 95% O2/5% CO2), and isometric tension was recorded. The endothelin-A (ETA) receptor antagonist FR139317, the combined ETA/ETB receptor antagonist bosentan, and the ETB-selective agonist sarafotoxin S6c were used. In old (and less so in adult) SHR, cumulative concentration-contraction curves to endothelin-1 showed a small contraction resistant to FR139317 (10(-5) mol/L) at 3 x 10(-9) to 10(-8) mol/L endothelin-1, which was completely inhibited by bosentan (10(-5) mol/L). This FR139317-resistant contraction to endothelin-1 was not present in WKY. Furthermore, in the presence of FR139317 (10(-5) mol/L), sarafotoxin S6c induced a stronger contraction in old SHR than in WKY (P < .05). In rings contracted with norepinephrine, sarafotoxin S6c caused endothelium-dependent relaxations in both strains; these relaxations were blocked by N omega-nitro-L-arginine methyl ester, indicating that nitric oxide is the mediator. In WKY but not SHR, release of nitric oxide by sarafotoxin S6c increased with age (P < .05). Thus, both ETA and ETB receptors mediate contraction to endothelin-1 in the renal artery from SHR but not WKY. ETB receptors on vascular smooth muscle seem to be unmasked with age in SHR, whereas those on endothelium (mediating nitric oxide release) exhibit more efficient responses with age in WKY.

Both ETA and ETB receptors mediate contraction to endothelin-1 in human blood vessels

BACKGROUND

Endothelin (ET)-1 has potent vascular effects. Two endothelin receptors have been cloned, namely, the ETA receptor, which preferentially binds ET-1, and the ETB receptor, which equally binds ET-1 and ET-3 and preferentially sarafotoxin S6c. We characterized endothelin receptor subtypes on vascular smooth muscle and endothelium of isolated human internal mammary artery (IMA) and vein (IMV) and porcine coronary artery (PCA) using the ETA antagonists FR139317 and BQ-123, the ETB ligand sarafotoxin S6c, and the ETA/ETB antagonist Ro 47-0203 (bosentan).

METHODS AND RESULTS

In endothelium-denuded IMA and PCA and less so in IMV, FR139317 and BQ-123 (in PCA only) shifted the concentration-contraction curves to ET-1 parallel to the right. However, even at 10(-5) mol/L, FR139317 did not inhibit a high-sensitivity portion of the concentration-contraction curve. Moreover, the ETB receptor agonist sarafotoxin S6c induced contraction in vessels preincubated with FR139317. IMV was significantly more sensitive to the contractile effect of ET-1 and sarafotoxin S6c than was IMA (P < .05). Prolonged incubation with sarafotoxin S6c (to downregulate ETB receptors) and FR139317 eliminated the contraction resistant to FR139317. The ETA/ETB receptor antagonist bosentan caused a parallel shift of the concentration-contraction curve to the right at all concentrations of endothelin. ETB receptor mRNA was detected by Northern blot analysis in IMA and aortic smooth muscle cells. In precontracted IMA and PCA with endothelium, sarafotoxin S6c did not cause endothelium-dependent relaxations, whereas transient responses occurred in IMV.

CONCLUSIONS

Vascular smooth muscle cells of human IMA, IMV, and PCA contain both ETA and ETB receptors, whereas the endothelium of IMA and PCA does not express functional ETB receptors linked to nitric oxide and/or prostacyclin production. Hence, inhibition of endothelin-induced contraction in patients requires the use of combined ETA/ETB antagonists.