bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the flexible genome complement of the commensal Escherichia coli strain A0 34/86 (O83 : K24 : H31)
Authors: Hejnova Jana , Dobrindt Ulrich , Nemcova Radka , Rusniok Christophe , Bomba Alojz , Frangeul Lionel , Hacker Jörg , Glaser Philippe , Sebo Peter , Buchrieser Carmen
Published: February 2005

Colonization by the commensal Escherichia coli strain A0 34/86 (O83 : K24 : H31) has proved to be safe and efficient in the prophylaxis and treatment of nosocomial infections and diarrhoea of preterm and newborn infants in Czech paediatric clinics over the past three decades. In searching for traits contributing to this beneficial effect related to the gut colonization capacity of the strain, the authors have analysed its genome by DNA–DNA hybridization to E. coli K-12 (MG1655) genomic DNA arrays and to ‘Pathoarrays’, as well as by multiplex PCR, bacterial artificial chromosome (BAC) library cloning and shotgun sequencing. Four hundred and ten E. coli K-12 ORFs were absent from A0 34/86, while 72 out of 456 genes associated with pathogenicity islands of E. coli and Shigella were also detected in E. coli A0 34/86. Furthermore, extraintestinal pathogenic E. coli-related genes involved in iron uptake and adhesion were detected by multiplex PCR, and genes encoding the HlyA and cytotoxic necrotizing factor toxins, together with 21 genes of the uropathogenic E. coli 536 pathogenicity island II, were identified by analysis of 2304 shotgun and 1344 BAC clone sequences of A0 34/86 DNA. Multiple sequence comparisons identified 31 kb of DNA specific for E. coli A0 34/86; some of the genes carried by this DNA may prove to be implicated in the colonization capacity of the strain, enabling it to outcompete pathogens. Among 100 examined BAC clones roughly covering the A0 34/86 genome, one reproducibly conferred on the laboratory strain DH10B an enhanced capacity to persist in the intestine of newborn piglets. Sequencing revealed that this BAC clone carried gene clusters encoding gluconate and mannonate metabolism, adhesion (fim), invasion (ibe) and restriction/modification functions. Hence, the genome of this clinically safe and highly efficient colonizer strain appears to harbour many ‘virulence-associated’ genes. These results highlight the thin line between bacterial ‘virulence’ and ‘fitness' or ‘colonization’ factors, and question the definition of enterobacterial virulence factors.
Osmotic shrinkage of cells of Synechocystis sp. PCC 6803 by water efflux via aquaporins regulates osmostress-inducible gene expression
Authors: Shapiguzov Alexey , Lyukevich Alexander A. , Allakhverdiev Suleyman I. , Sergeyenko Tatiana V. , Suzuki Iwane , Murata Norio , Los Dmitry A.
Published: February 2005

Osmotic stress causes water molecules to efflux from cells through the cytoplasmic membrane. This study reveals that targeted mutation of the aqpZ gene, encoding an aquaporin water channel protein, in the cyanobacterium Synechocystis sp. PCC 6803 prevents the osmotic shrinkage of cells, suggesting that it is the water channel rather than the lipid bilayer that is primarily responsible for water transition through the membrane of this organism. The observations suggest that the aquaporin-mediated shrinkage of the Synechocystis cells plays an important role in changes of gene expression in response to hyperosmotic stress.
Suppression subtractive hybridization as a basis to assess Mycoplasma agalactiae and Mycoplasma bovis genomic diversity and species-specific sequences
Authors: Marenda Marc S. , Sagné Evelyne , Poumarat François , Citti Christine
Published: February 2005

The phylogenically related Mycoplasma agalactiae and Mycoplasma bovis species are two ruminant pathogens difficult to differentiate and for which a limited amount of sequence data are available. To assess the degree of genomic diversity existing between and within these mycoplasma species, sets of DNA fragments specific for M. bovis type-strain PG45 or for M. agalactiae type-strain PG2 were isolated by suppression subtractive hybridization and used as probes on a panel of M. agalactiae and M. bovis field isolates. Results indicated that approximately 70 % of the DNA fragments specific to one or the other type strain are represented in all field isolates of the corresponding species. Only one M. bovis isolate, which was first classified as M. agalactiae, reacted with 15 % of the PG2-specific probes, while several M. agalactiae isolates reacted with 15 % of the PG45-specific probes. Sequence analyses indicated that most of the genomic diversity observed within one species is related to ORFs with (i) no homologies to proteins recorded in the databases or (ii) homologies to proteins encoded by restriction modification systems. Reminiscent of gene transfer as a means for genomic diversity, a PG45-specific DNA fragment with significant homologies to a central protein of an integrative conjugative element of Mycoplasma fermentans (ICEF) was found in most M. bovis field isolates and in a few M. agalactiae isolates. Finally, sequences encoding part of DNA polymerase III were found in both sets of M. agalactiae- and M. bovis-specific DNA fragments and were used to design a species-specific PCR assay for the identification and differentiation of M. agalactiae and M. bovis.
The putative autolysin regulator LytR in Streptococcus mutans plays a role in cell division and is growth-phase regulated
Authors: Chatfield Christa H. , Koo Hyun , Quivey, Robert G.
Published: February 2005

Streptococcus mutans is the primary odontopathogen present in supragingival plaque and causes the oral disease known as dental caries. Colonization of the oral cavity by S. mutans requires the bacteria to adhere to the tooth surface and occurs by both sucrose-dependent and -independent mechanisms. Sucrose-independent adhesion of S. mutans
in vitro has been shown to involve an ORF (ORF0317) encoding a homologue (39 %) to LytR, a regulator of autolysin activity in Bacillus subtilis. The protein encoded by ORF0317, LytR, belongs to the LytR/CpsA/Psr protein family. This family has a putative role in cell-wall structural maintenance, possibly through autolysin regulation. Autolysins have also been shown to be important in surface adhesion in Lactococcus lactis and in the pathogenic properties of Streptococcus pneumoniae. To investigate the role of autolysins in the adhesion and pathogenesis of S. mutans, a LytR mutant was constructed. The mutant grows in long chains, which may indicate a defect in cell division. Further experiments with the mutant strain show increased autolytic activity, indicating that LytR attenuates S. mutans autolytic activity, possibly through regulation of the expression of autolytic enzymes. No defect in cell-to-surface adherence or biofilm growth was seen in the LytR mutant. However, a connection between cell growth phase and transcription of lytR was found.
Bacillus cereus Fur regulates iron metabolism and is required for full virulence
Authors: Harvie Duncan R. , Vílchez Susana , Steggles James R. , Ellar David J.
Published: February 2005

A homologue of the Bacillus subtilis fur gene was identified in Bacillus cereus and characterized. The predicted amino acid sequence of the cloned gene was found to be highly similar to other members of the Fur family of transcriptional regulators. The B. cereus fur gene was shown to partially complement an Escherichia coli fur mutant. Purified B. cereus Fur bound specifically to a 19 bp DNA sequence homologous to the B. subtilis Fur box in a metal-dependent manner. Analysis of the available B. cereus genome data identified a number of genes which contain predicted Fur box sequences in the promoter region. Many of these genes are predicted to play a role in bacterial iron uptake and metabolism, but several have also been implicated as having a role in virulence. Fur and iron regulation of a siderophore biosynthesis operon was confirmed in a β-galactosidase assay. A B. cereus fur null strain was constructed by allelic replacement of the chromosomal gene with a copy disrupted with a kanamycin resistance cassette. The Δfur mutant was found to constitutively express siderophores, to accumulate iron intracellularly to a level approximately threefold greater than the wild-type, and to be hypersensitive to hydrogen peroxide. In an insect infection model, the virulence of the fur null strain was found to be significantly attenuated, highlighting the essential role played by Fur in the virulence of this pathogen.
Commonalities and Differences in Word Identification Skills Among Learners of English as a Second Language
Authors: Wang Min , Koda Keiko
Published: February 2005

This study examined word identification skills among Chinese and Korean college students learning to read English as a second language in a naming experiment and an auditory category judgment task. Both groups demonstrated faster and more accurate naming performance on high‐frequency words than low‐frequency words and on regular words than exception words. Moreover, the difference in naming accuracies between regular and exception words was more pronounced for low‐frequency words than for high‐frequency words. A first language (L1) effect was observed: The Korean students were overall more accurate in naming all categories of words, showed a higher percentage of regularization errors in naming low‐frequency exception words, and were more accurate and faster in auditory meaning retrieval. These findings suggest that there are both common and unique processes in learning to read English for students from different L1 backgrounds.
Developing, Piloting, and Validating an Instrument to Measure Young Learners’ Aptitude
Authors: Kiss Csilla , Nikolov Marianne
Published: February 2005

This study aimed to develop, pilot, and validate an aptitude test for Hungarian learners of English. A literature review on the construct and tests of aptitude is followed by two parts: a pilot phase on the development of a new aptitude test and a main study involving 419 12‐year‐old children in 10 schools. Data were collected on the aptitude test, English proficiency tests, and a measure of learners’ motivation. The article explores how aptitude scores relate to learners’ performances on the proficiency measure, motivation, gender, school achievements, and grades in English. The results of a multiple‐regression analysis indicate that the variable of language aptitude explained over 20% of the variation in English language performance, thus proving to be the best predictor of outcomes.
Comparison of the Performance of College Students Classified as ADHD, LD, and LD/ADHD in Foreign Language Courses
Authors: Sparks Richard L. , Javorsky James , Philips Lois
Published: February 2005

In this study, college students classified as having attention deficit hyperactivity disorder (ADHD) who had fulfilled the foreign language (FL) requirement were compared with students classified as learning disabled (LD) or both LD and ADHD who had either substituted courses for the college FL requirement (petition) or had passed FL courses (nonpetition) on cognitive and academic achievement measures and in FL course grades. Findings revealed few between‐group differences on the testing measures and also showed that all 5 groups scored in the average to above‐average range on all measures of cognitive ability and academic achievement and achieved primarily average to above‐average grades in college FL courses. Results indicated that petition status and disability classification were not important in differentiating the 5 groups’ cognitive ability, academic achievement skills, and graduating grade point average.
Information Content and Timing of Earnings Announcements
Authors: Chen Gongmeng , Cheng Louis T. W. , Gao Ning
Published: February 2005

Abstract:  The China Securities Regulatory Commission requires all listed firms to make earnings announcements by the end of April each year. This requirement creates a unique opportunity for us to evaluate the timing of earnings announcements in a four‐month cluster. Firms, which are willing to make early announcements, tend to surprise the market, as indicated by the higher volume and price reactions. Later announcements are more predictable, as indicated by the lower volume and price reactions. These results indicate that an information asymmetry exists between early and late earnings announcements in Mainland China.
Directors’ Recommendations in Takeovers: An Agency and Governance Analysis
Authors: Henry Darren
Published: February 2005

Abstract:  This paper evaluates whether directors of target companies make response recommendations in takeovers which are consistent with the interests of shareholders, by examining the relationship between target director recommendations and associated takeover characteristics and ownership and corporate governance characteristics of target companies. The findings suggest that response recommendations appear to be more closely associated with the self‐interest of directors rather than shareholders’ concerns, and that common governance initiatives aimed at aligning the interests of shareholders and managers are ineffective in resolving this agency problem. The results suggest the need for legislative or judicial reforms in Australia to encourage takeover activity and reduce takeover hostility.
THIS ARTICLE HAS BEEN RETRACTED A Framework for Market Discipline in Bank Regulatory Design
Authors: Hamalainen Paul , Hall Maximilian , Howcroft Barry
Published: February 2005

Abstract: Given current debates on the future direction of regulatory design, the first objective of this paper is to contextualise the issues surrounding bank market discipline. Accordingly, the paper raises awareness of the current key themes within incentive‐based regulatory design and analyses the theory underlying market discipline. This leads to the creation of a theoretical framework of market discipline, which provides a powerful tool for understanding the conditions necessary for effective market discipline and for assessing the findings of market discipline‐related empirical research. The second objective is to emphasise the suitability of the theoretical framework for debates on contemporary market discipline and aiding future bank regulatory policy design, in particular, how to incorporate suitable, incentive mechanisms in international banking regulation.
Signalling and the Long‐run Performance of Spanish Initial Public Offerings (IPOs)
Authors: Álvarez Susana , González Víctor M.
Published: February 2005

Abstract:  Academic research into firms that have gone public has focused on the study of two anomalies: initial underpricing and long‐run underperformance. We analyse Spanish Initial Public Offerings to provide additional evidence on the long‐run performance of IPOs and its relationship with initial underpricing. Results reveal the existence of negative long‐run abnormal stock returns, in line with the international literature. Long‐run performance presents a positive relationship with underpricing and the volume of funds obtained in seasoned offerings, in consonance with the predictions of Allen and Faulhaber (1989), Welch (1989) and Grinblatt and Hwang (1989).
Exploiting the RNA interference pathway to counter hepatitis B virus replication
Authors: Arbuthnot Patrick , Carmona Sergio , Ely Abdullah
Published: February 2005

Abstract: Chronic infection with hepatitis B virus (HBV) is endemic to sub‐Saharan Africa and parts of Asia where persistence of the virus is commonly associated with complicating cirrhosis and hepatocellular carcinoma (HCC). Licensed therapies for HBV are partially effective in selected patients and development of novel treatments remains an important global medical objective. HBV has an unusually compact genome that restricts the ability of the virus to evade potentially therapeutic nucleic acid hybridization. Thus, exploiting the RNA interference (RNAi) pathway, which enables sequence‐specific target RNA degradation using small interfering RNA (siRNA), is well suited to developing novel treatment for HBV infection. Several studies, both in vitro and in vivo, have demonstrated that HBV replication can be inhibited in transfected cells by synthetic siRNA duplexes and also Pol III‐derived short hairpin RNA (shRNA) sequences. The effectiveness of anti‐HBV sequences varies considerably, and is likely to result from differences in activation of the RNAi pathway by individual siRNA species. Exclusion of potentially toxic off‐target effects and also development of efficient methods of hepatotropic nucleic acid delivery are important prerequisites before RNAi can be used successfully for anti‐HBV treatment.
In vivo expression patterns of survivin and its splicing variants in chronic liver disease and hepatocellular carcinoma
Authors: Takashima Hidetaka , Nakajima Tomoki , Moriguchi Michihisa , Sekoguchi Satoru , Nishikawa Taichiro , Watanabe Tadashi , Katagishi Tatsuo , Kimura Hiroyuki , Minami Masahito , Itoh Yoshito , Kagawa Keizo , Okanoue Takeshi
Published: February 2005

Abstract: Aim: Our aim was to clarify the significance of expression levels and post‐transcriptional splicing patterns of survivin during multistep hepatocarcinogenesis and tumor progression.

Methods: Using immunohistochemistry, we first elucidated the expression of survivin protein in tissues of hepatocellular carcinoma (HCC) and the adjacent non‐cancerous tissues. Furthermore, we investigated survivin gene expression patterns in these tissues.

Results: Survivin protein was expressed not only in most HCC tissues but also in some cirrhotic nodules. In non‐cancerous regions, the levels of survivin mRNA increased in proportion to their stage of progression. Survivin protein was expressed mainly in periportal areas, where proliferating cells were localized. In HCC, mRNA levels of survivin and survivin ΔEx3 correlated with high proliferative activity, whereas the levels of surviving 2B did not.

Discussion: These findings of mRNA and protein expressions of survivin in chronically injured avers indicate that it has an important role in hepatocarcinogenesis. A lack of correlation between proliferative activity and survivin 2B mRNA levels in HCC is suggestive of a previous hypothesis that this variant decreases sruvivin function in a dominan negative manner. Thus, our data suggest different functions of these splicing variants and their important roles in tumor progression.
Hepatocellular carcinoma – survival and clinical characteristics in relation to various histologic molecular markers in Western patients
Authors: Schöniger‐Hekele Maximilian , Hänel Sabine , Wrba Fritz , Müller Christian
Published: February 2005

Abstract: Background:Many genes participate in the regulation of cell proliferation and growth of tumor cells. Altered expression and loss of function of some of these gene products have been found in malignant tumors and correlated with progression and poor prognosis.

Aims:Our aim was to correlate the expression of various molecular histologic markers with tumor characteristics and survival time of patients with hepatocellular carcinoma (HCC).

Patients and methods:Tumor tissues of 81 patients with HCC were investigated immunohistochemically for the expression of cellular proliferation markers Mib1 (Ki67) and c‐erbB‐2 (HER2/neu), cellcycle markers (p53, mdm2 and p21), CD81 (TAPA1), a marker shown to be associated with metastasis, and human leukocyte antigen (HLA)‐DR expression, involved in immunological antigen presentation.

Results:p21 was expressed in a higher percentage (83.3 vs. 50%,P=0.014) in undifferentiated histological tumor grades (Edmondson Steiner G3 vs. G1/G2). HCC in patients with enlarged lymph nodes expressed HLA‐DR in a higher percentage (28.6%) than tumors without lymph node enlargement (5.7%,P=0.006). Patients with distant metastases were less likely to express CD 81 (11.1%) on tumor cells than patients without distant metastases (38.3%,P=0.0335). No other correlation with clinical or tumor characteristics or molecular histologic markers investigated was found. P53 accumulating patients showed a worse survival than patients with tumors p53 non‐accumulating (median 4.1 months vs. median 9.3 months,P=0.01798). Neither the expression nor the non‐expression of proliferation, cell cycle, immunologic or cell adhesion markers was associated with differences in survival. However, patients with a low expression of cell cycle marker mdm2 survived significantly longer (median 9.4 months) as compared with patients with high expression (median 3.9 months).

Conclusion:Our results suggest that p53 nuclear accumulation and mdm2 high expression are associated with poor survival in patients withHCC. Furthermore, patients with enlarged lymph nodes had HLA‐DR‐positive tumors more frequently and patients with distant metastases had tumors with CD81 expression less often.
Decreased expression of peroxisome proliferator‐activated receptor α and liver fatty acid binding protein after partial hepatectomy of rats and mice
Authors: Skrtic Stanko , Carlsson Linda , Ljungberg Anna , Lindén Daniel , Michalik Liliane , Wahli Walter , Oscarsson Jan
Published: February 2005

Abstract:
Background Aims: Marked changes in metabolism, including liver steatosis and hypoglycemia, occur after partial hepatectomy. Peroxisome proliferator‐activated receptor α (PPARα) is a nuclear hormone receptor that is activated by fatty acids and involved in hepatic fatty acid metabolism and regeneration. Liver fatty acid binding protein (LFABP) is an abundant protein in liver cytosol whose expression is regulated by PPARα. It is involved in fatty acid uptake and diffusion and in PPARα signaling. The aim of this study was to investigate the expression of PPARα and LFABP during liver regeneration.

Methods: Male Sprague–Dawley rats and male C57 Bl/6 mice were subjected to 2/3 hepatectomy and LFABP and PPARα mRNA and protein levels were measured at different time points after surgery. The effect of partial hepatectomy was followed during 48 h in rats and 72 h in mice.

Results: PPARα mRNA and protein levels were decreased 26 h after hepatectomy of rats. The LFABP mRNA and protein levels paralleled those of PPARα and were also decreased 26 h after hepatectomy. In mice, the mRNA level was decreased after 36 and 72 h after hepatectomy. In this case, LFABP mRNA levels decreased more slowly after partial hepatectomy than in rats.

Conclusions: A marked decrease in PPARα expression may be important for changed gene expression, e.g. LFABP, and metabolic changes, such as hypoglycemia, during liver regeneration.
Preneoplastic lesions in human hepatocarcinogenesis
Authors: Libbrecht Louis , Desmet Valeer , Roskams Tania
Published: February 2005

Abstract: The early stages of hepatocarcinogenesis in human chronic liver diseases are characterized by the emergence of preneoplastic lesions of which some will eventually develop into hepatocellular carcinoma (HCC). Basic studies on the genetic and epigenetic alterations of these preneoplastic lesions may eventually lead to new therapeutic strategies. Clinicopathological studies are also important in order to determine optimal management of patients with a preneoplastic lesion. This article aims to provide a comprehensive review of the current concepts of preneoplastic lesion in chronic liver diseases. The microscopical small‐cell dysplastic focus is the smallest morphologically recognizable precursor lesion of HCC and therefore is a logical target of study to elucidate the earliest events in hepatocarcinogenesis. In contrast, large‐cell dysplasia is not a precursor lesion, but appears to be of clinical value because of its good predictive value for development of HCC. Dysplastic nodules (DNs) are macroscopically recognizable precursor lesions of HCC and high‐grade DNs (HGDNs) have a risk of malignant transformation. Detection of DNs and correct differentiation from small HCC (<2 cm) is sometimes difficult, especially when only imaging techniques are used. Additional clinicopathological studies on identification and optimal treatment of DNs are necessary. Molecular studies on HGDNs and small HCCs may yield much information on the genetic mechanisms involved in the transition from severe dysplasia to early malignancy. In contrast, currently available data indicate that (large) regenerative nodules do not represent a distinct step in hepatocarcinogenesis. Animal models will be helpful in the further unravelling of human HCC development, provided that studies are performed on models that are good representatives of human hepatocarcinogenesis. We propose three criteria by which good mimickers can be identified.
Nitric oxide synthases inhibition results in renal failure improvement in cirrhotic rats
Authors: Islas‐Carbajal M. C. , Covarrubias A. , Grijalva G. , Alvarez‐Rodríguez A. , Armendáriz‐Borunda J. , Rincón‐Sánchez A. R.
Published: February 2005

Abstract: Nitric oxide (NO) has been implicated in cirrhosis and might be implicated in renal failure end‐stage cirrhosis.

Aim: Our aim was to evaluate NO role in renal failure induced during decompensated cirrhosis, using the following inhibitors: aminoguanidine (AG), a specific inducible nitric oxide synthase (iNOS) inhibitor and NG‐nitro‐l‐arginine methyl ester (L‐NAME), a nonselective blocker of NOS isoforms.

Methods: Endothelial (eNOS) and iNOS gene expression was analyzed by reverse transcriptase‐polymerase chain reaction. Cirrhotic rats received a single intragastric dose of CCl4 to induce acute liver damage (ALD).

Results: After ALD, aspartate aminotransferase highest levels were observed in rats treated with AG and ALT in rats treated with L‐NAME. Inhibitors decreased creatinine serum levels to normal values and serum sodium levels re‐established after the third day of ALD. L‐NAME diminished (P<0.05) eNOS RNA renal expression. Renal iNOS with no inhibitor was overexpressed but was down‐regulated by AG treatment. Liver eNOS RNA expression had a decreased expression before ALD in cirrhotic rats, but L‐NAME treatment down‐regulated eNOS after ALD. AG induced an important iNOS liver decrease.

Conclusion: Both inhibitors improved renal function, although AG displayed a better effect and did not aggravate liver function. We concluded that NOS isoforms are implicated in the renal pathophysiologic events induced by ALD.
Decreased risk of hepatocellular carcinoma in patients with chronic hepatitis C whose serum alanine aminotransferase levels became less than twice the upper limit of normal following interferon therapy
Authors: Moriyama Mitsuhiko , Matsumura Hiroshi , Aoki Hiroshi , Shimizu Toshihiro , Yamagami Hiroaki , Shioda Atsuo , Kaneko Miki , Goto Iori , Tanaka Naohide , Arakawa Yasuyuki
Published: February 2005

Abstract: Aim: The incidence of hepatocellular carcinoma (HCC) in C‐viral chronic hepatitis (CH) and liver cirrhosis (LC) patients after interferon (IFN) therapy was evaluated according to alanine aminotransferase (ALT) levels.

Patients: Two hundred sixty‐nine patients with C‐viral CH and LC were treated with natural IFN‐α. The efficacy of IFN therapy was evaluated based on virologic response and ALT levels using the following groups: virologic‐sustained responders (VSR); biochemical‐sustained responders (BSR); partial responders (PR), which consisted of BSR patients whose serum ALT levels later relapsed; non‐responders (NR)1, which included patients with serum ALT levels that were usually less than 80 IU/l; and NR2, NR with ALT levels persistently more than 80 IU/l.

Results: Of the 269 patients, 22 (8.2%) developed HCC after IFN therapy. The incidence of HCC (%/patient/year) was 0.78%, 0%, 0%, 0.17%, 4.68% in VSR, BR, PR, NR1, NR2, respectively. Multivariate analysis revealed that an increase in ALT levels to more than 80 IU/l is an important risk factor for the occurrence of HCC.

Conclusions: We concluded that the patients with ALT levels less than twice the upper limit of normal after IFN therapy have a reduced risk of progression to HCC from C‐viral chronic liver disease.
Normal liver regeneration and liver cell apoptosis after partial hepatectomy in tumor necrosis factor‐α‐deficient mice
Authors: Hayashi Hideki , Nagaki Masahito , Imose Motoaki , Osawa Yosuke , Kimura Kiminori , Takai Shinji , Imao Motohiro , Naiki Takafumi , Kato Tomohiro , Moriwaki Hisataka
Published: February 2005

Abstract: Aims/Background: Tumor necrosis factor‐α (TNF‐α) is known as a proinflammatory cytokine that has been implicated as a contributing factor in a number of disease processes. TNF‐α also influences liver repair following hepatotoxic damage, and regeneration following partial hepatectomy (PH). The aim of this study was to assess the mechanism by which TNF‐α influences liver cell apoptosis and regeneration following PH in TNF‐α‐deficient (TNF‐α−/−) mice.

Methods: PH was performed in wild mice and TNF‐α−/− mice.

Results: In both groups, serum alanine aminotransferase and serum total bilirubin levels comparably peaked at 6 and 48 h after PH, respectively. No differences were observed in hepatocyte proliferation, as determined by mitotic and the proliferating cell nuclear antigen labeling indices, between TNF‐α+/+ and TNF‐α−/− mice. Few terminal deoxynucleotidyl transferase nick end‐labeling‐positive hepatocytes were seen in either type of mice. Nuclear factor‐κB DNA binding activity in the remaining liver of TNF‐α−/− mice after PH was similar to that of control mice. Ribonuclease protection assay showed that transforming growth factor β1 mRNA was up‐regulated comparably in the livers of the two groups, and that other cytokines were hardly seen in either. Interleukin‐6/ signal transducer and activator of transcription‐3‐dependent pathway was not affected in TNF‐α−/− mice.

Conclusions: These findings suggest that TNF‐α has little influence on liver regeneration and liver cell apoptosis after PH in mice.
Outcome after orthotopic liver transplantation in five HIV‐infected patients with virus hepatitis‐induced cirrhosis
Authors: Radecke Klaus , Frühauf Nils R. , Miller Michael , Ross Birgit , Köditz Roland , Malagó Massimo , Broelsch Christoph E. , Gerken Guido , Treichel Ulrich
Published: February 2005

Abstract: Background: We report on our experiences with orthotopic liver transplantation (OLT) in HIV‐infected patients. Between July 1998 and October 2001, five HIV‐infected patients underwent OLT because of virus‐induced liver cirrhosis. One patient suffered from hepatitis B virus (HBV)‐, three patients from hepatitis C virus (HCV)‐ and one patient from HCV/HBV/HDV‐related cirrhosis (HDV, hepatitis D virus). The mean duration of HIV infection was 15 years. Patients were prospectively followed up with a mean duration of 25.6 months.

Results: Three patients died 3, 10 and 31 months after OLT, respectively, due to graft failure. The causes of graft failure were: recurrent thrombosis of the hepatic artery, HCV‐associated cholestatic hepatitis and chemotherapy‐induced liver damage due to Hodgkin's disease, which was diagnosed 17 months after OLT, in addition to chronic HCV disease. The two survivors show a stable liver function and non‐progredient HIV infection under antiretroviral therapy 61 and 23 months after OLT, respectively.

Conclusions: A medium‐ or even long‐term survival after OLT can be achieved in HIV‐infected patients without progression of HIV disease under antiretroviral therapy. However, in our study three out of five patients died due to graft failure. Therefore, prognostic criteria have to be defined for the selection of HIV‐infected patients, who may benefit from OLT.
Hepatic microcirculation assessed by positron emission tomography of first‐pass ammonia metabolism in porcine liver
Authors: Keiding Susanne , Munk Ole Lajord , Vilstrup Hendrik , Nielsen Dennis Tønner , Roelsgaard Klaus , Bass Ludvik
Published: February 2005

Abstract: Aims/Background: Intrahepatic branching of the hepatic artery (HA) to liver microcirculatory units, the acini, is more heterogeneous than that of the portal vein (PV). Furthermore, part of HA blood enters the sinusoid partially downstream between the in‐ and outlets. We examined the effects of these vascular variations on porcine hepatic first‐pass ammonia metabolism, which is characterised by high uptake and separate periportal urea and perivenous glutamine formations.

Methods: 13NH3 was given via the PV, HA or caval vein, followed by 22 min dynamic liver positron emission tomography (PET) recordings in six pigs. Heterogeneity of liver 13N‐metabolism was quantified by the coefficient of variation of tissue 13N‐radioactivity measured 10 min after tracer infusion. Sinusoidal zonal clearances of 13NH3 into 13N‐urea and 13N‐glutamine were calculated by kinetic PET modelling.

Results: Liver metabolic heterogeneity was 0.65±0.20 (mean±SD, n=6) following 13NH3‐infusion into HA, 0.34±0.17 into PV and 0.10±0.02 into the caval vein. Clearance of 13NH3 to 13N‐urea was of similar magnitude following 13NH3 administration into HA and PV: 0.27±0.11 ml/min/g (mean±SD) and 0.29±0.09 ml/min/g, respectively. Clearances of 13NH3 to 13N‐glutamine when 13NH3 was given into HA and PV were also similar: 0.47±0.18 and 0.50±0.13 ml/min/g, respectively.

Conclusions: The present measurements of the hepatic metabolism of 13NH3 showed metabolic heterogeneity compatible with variation of the HA supply of the acini. Second, results of PET modelling of the sinusoidal zonation metabolism of 13NH3 to 13N‐urea and to 13N‐glutamine did not indicate metabolically important partial downstream arterial entry into the sinusoids.
The influence of brain death on liver function
Authors: Olinga Peter , Van Der Hoeven Joost A. B. , Merema Marjolijn T. , Freund Rennie L. , Ploeg Rutger J. , Groothuis Geny M. M.
Published: February 2005

Abstract: Background: In this study, we investigated the influence of brain death on inflammatory response and the effects of brain death on liver function both directly after explantation and after reoxygenation.

Methods: The influence of brain death on liver function was studied in rats using a brain death model and the liver slice model to mimic reoxygenation. Liver function was assessed by measuring the ATP content and the ATP‐driven urea synthesis. The activation of non‐parenchymal cells was studied by measuring mRNA levels of IL‐10, cytokine production (IL‐10 and IL‐1β) and inducible nitric oxide synthases (iNOS) upregulation (mRNA) and protein level.

Results: Brain death had no direct influence on the ATP content of the liver. However, it led to induction of several cytokines because of activation of non‐parenchymal cells, which led to upregulation of iNOS and to nitric oxide metabolites production. It is known that cytokine production may influence the drug metabolism capacity; however, no influence of brain death on drug metabolism was observed. An explanation may be the relatively short experimental period.

Conclusions: Kupffer cells seem to be activated during the onset of brain death induction; however, they become quiescent when liver slices of brain dead rats were reoxygenated during incubation. Other non‐parenchymal cells, possibly the endothelial cells, remain activated during incubation and reoxygenation in slices from brain death donors but not in slices from control livers. Future experiments in our rat liver transplantation model need to elucidate the implications of these findings.
The influence of spleen size on liver regeneration after major hepatectomy in normal and early cirrhotic liver
Authors: Shan Yan‐Shen , Hsieh Yu‐Hsiang , Sy Edgar D , Chiu Nan‐Tsing , Lin Pin‐Wen
Published: February 2005

Abstract: Background/Purpose: The relationship between liver regeneration and spleen size after major hepatectomy in normal and cirrhotic liver was studied by single photon emission computed tomography (SPECT).

Materials and methods: Twenty‐six patients, 18 patients with normal liver and eight patients with cirrhotic liver, receiving major hepatectomy were included. Liver and spleen volumes were measured by SPECT before major hepatectomy, 6 months, 1 year and 2 years after operation. The correlation of liver and spleen volume during liver regeneration was analyzed.

Results: In both groups, the residual liver volume increased within the first year and decreased in the second year. No difference in regeneration ability was found. The spleen volume in cirrhotic liver was increased, with a trend similar to normal liver during the first year. In contrast, the increased spleen volume persisted up to the second year in cirrhotic patients. Age per year, the female sex, and body surface index had a positive correlation with increased percentage of liver volume. The spleen volume per 100 ml with time played a significantly negative role in increasing percentage of liver volume, confidence interval: −2.16 to −27.92, P=0.011.

Conclusion: In early cirrhotic liver within normal functional limits, the liver still could regenerate as a normal liver after major hepatectomy in 1 year. Age, the female sex, and body surface index had positive correlation but the size of spleen volume played a negative role to regenerative liver volume.
Effect of lipopolysaccharide on in vivo and genetic regulation of rat urea synthesis
Authors: Nielsen Susanne Schouw , Grøfte Thorbjørn , Tygstrup Niels , Vilstrup Hendrik
Published: February 2005

Abstract: Background: The acute phase response causes a negative nitrogen balance. It is unknown whether this involves regulation of hepatic urea synthesis.

Methods: We examined the in vivo capacity of urea nitrogen synthesis (CUNS), mRNA levels of urea cycle enzyme genes and galactose elimination capacity (GEC) during moderate and severe acute phase response induced by low‐ and high‐dose lipopolysaccharide (LPS) in rats.

Results: Low‐dose LPS doubled CUNS (P<0.05), decreased the mRNA level of the rate‐limiting urea cycle enzyme (arginino succinate synthetase (ASS) by 26% (P<0.05) and did not change GEC. High‐dose LPS did not change CUNS, decreased the mRNA level of the flux‐generating enzyme carbamoyl phosphate synthetase (CPS) by 11% (P<0.05) and the rate‐limiting urea cycle enzyme (ASS) by 27% (P<0.05) and almost halved GEC (P<0.05).

Conclusion: The moderate acute phase response up‐regulated in vivo urea synthesis but had the opposite effect on gene level. The severe acute phase response decreased the functional liver mass that attenuated the increase in urea synthesis.
Malignant transformation of the cultured human hepatocytes induced by hepatitis C virus core protein
Authors: Shan Yu , Chen Xi‐gu , Huang Bing , Hu An‐bin , Xiao Dong , Guo Zhong‐min
Published: February 2005

Abstract: Background/Aim: Hepatitis C virus core protein (HCV‐C) has been known to play an important role in hepatocarcinogenesis. But, up to now there is no certain evidence in pathomorphology directly supporting this standpoint. In this study, a human hepatocytes model expressing HCV‐C was established for investigating the influence of HCV‐C on hepatocytes biological properties.

Methods: The HCV‐C expression plasmid, PcDNA3‐C, was transfected into Chang‐liver cells to establish HCV‐C expressing cells. Proliferation rate and variation index of DNA content of these cells were measured by MTT and FCM. The malignant transformation of these cells was observed by electron microscope. Furthermore, these cells were subcutaneous injected into nude mice to observed their tumor genesis.

Results: Proliferation rate and variation index of DNA content of these cells markedly increased. 10/10 of BALB/c‐nu/nu nude mice generated tumors at 3 weeks after subcutaneous inoculation of the HCV‐C expressing cells. And, histological structure of the tumors coincided with that of hepatocarcinoma.

Conclusions: The HCV‐C may play a key role in hepatocarcinogenesis resulting from HCV infection.
CHARACTERIZATION OFOSTREOPSISANDCOOLIA(DINOPHYCEAE) ISOLATES IN THE WESTERN MEDITERRANEAN SEA BASED ON MORPHOLOGY, TOXICITY AND INTERNAL TRANSCRIBED SPACER 5.8S rDNA SEQUENCES1
Authors: Penna Antonella , Vila Magda , Fraga Santiago , Giacobbe Maria Grazia , Andreoni Francesca , Riobó Pilar , Vernesi Cristiano
Published: February 2005

Several isolates of epiphytic dinoflagellates belonging to the generaOstreopsisSchmidt andCooliaMeunier from the western Mediterranean Sea were examined by LM and EM, toxicity assays, and internal transcribed spacer (ITS) regions of nuclear rDNA, and 5.8S rDNA were sequenced. Morphological comparisons based on the analyses of cell shape, size, thecal plates, and surface ornamentation revealed two distinct species in the western Mediterranean:O. cf.siamensisSchmidt from the Catalan, Andalusian, and Sicilian coasts andO. ovataFukuyo from the Ligurian coast, southern Tyrrhenian Sea, and Balearic Islands. BothOstreopsisspecies were toxic; however, no differences in toxicity were detected between the twoOstreopsisspecies.Coolia monotisMeunier was nontoxic. The morphological studies were supported by phylogenetic analyses; all western Mediterranean isolates ofO. cf.siamensisshowed ITS and 5.8S rDNA sequences identical to each other and so did those ofO. ovata, whereas high genetic diversity was detected between the western Mediterranean and Asian isolates ofO. ovata. The nucleotide sequence analyses of theC. monotisstrains showed that allC. monotisisolates from Europe formed a homogeneous clade. Further, the genetic diversity was high between the European and AsianC. monotisisolates. In this study, genetic markers combined with morphology and toxicity analyses was useful in the taxonomic and phylogenetic studies of the Ostreopsidaceae in a temperate area.
BENTHIC DIATOM AUTECOLOGY AND INFERENCE MODEL DEVELOPMENT FROM THE CANADIAN HIGH ARCTIC ARCHIPELAGO1
Authors: Antoniades Dermot , Douglas Marianne S. V. , Smol John P.
Published: February 2005

Diatom assemblages were analyzed from 64 lakes and ponds from Alert, Ellesmere Island and Mould Bay, Prince Patrick Island in the Canadian High Arctic Archipelago. Diverse water chemistry conditions and diatom communities were present in these sites. Small benthic taxa typically dominated diatom communities; however, assemblages were markedly different between Alert and Mould Bay sites in response to disparate water chemistry characteristics in the two regions. The most abundant taxa belonged to the genera Navicula, Cymbella, Achnanthes, Nitzschia, and Pinnularia. Canonical correspondence analysis indicated that pH, specific conductivity, dissolved organic carbon, and total phosphorus were the most important limnological variables in determining species composition. Diatom inference models were developed for pH, specific conductivity, and dissolved organic carbon using weighted averaging and weighted averaging partial least squares techniques; these had root mean square error of prediction/r2boot values of 0.40/0.77, 0.28/0.70, and 0.24/0.55, respectively. These models are applicable to sites with large ranges of taxonomic and limnological variation and will allow the reconstruction of past changes of climate‐related limnological parameters from biostratigraphic records in future paleolimnological studies.
GROWTH INHIBITION AND TOXICITY OF THE DIATOM ALDEHYDE 2‐TRANS, 4‐TRANS‐DECADIENAL ON THALASSIOSIRA WEISSFLOGII (BACILLARIOPHYCEAE)1
Authors: Casotti Raffaella , Mazza Sabina , Brunet Christophe , Vantrepotte Vincent , Ianora Adrianna , Miralto Antonio
Published: February 2005

A common aldehyde present in marine and freshwater diatoms, 2‐trans, 4‐trans‐decadienal (A3), is involved in the wound‐activated response of diatoms to copepod grazing. Upon breakage of the diatom cell membrane, aldehydes are enzymatically produced by the rapid conversion of precursors and strongly impact copepod reproduction by impairing egg production and hatching success, inducing teratogenic embryos modifications. In this study, A3 was assayed with the marine diatom Thalassiosira weissflogii (Grunow) Fryxell et Hasle. The aldehyde concentration necessary to reduce 50% growth rate (EC50) was 0.29 mg·L−1. Decadienal was found to inhibit T. weissflogii cell growth in a dose‐ and time‐dependent manner, with irreversible effects after 24 h of exposure. Decadienal induced a degenerative process, through modifications of cell membrane characteristics, interference with cell cycle progression, and with cell metabolic activity, leading to cell death. A preferential action of A3 on dividing cells was observed. Photosynthetic efficiency significantly decreased upon exposure to the aldehyde, paralleled by an increase in diatoxanthin, suggesting a protective role of this xanthophyll, usually involved in photoprotection. Dying cells exhibited the morphological and biochemical features that bear close resemblance to apoptosis of mammalian cells, including cell shrinkage, chromatin condensation, and degradation of nuclear DNA to nucleosomal size fragments. These data are the first direct evidence to show aldehydes are toxic to diatoms. We suggest a possible nontoxic role of such compounds as chemical signals of unfavorable conditions within the phytoplankton communities, which may be relevant for the population dynamics of diatoms during blooms.
DIVERSITY IN THE GENUS SKELETONEMA (BACILLARIOPHYCEAE). I. A REEXAMINATION OF THE TYPE MATERIAL OF S. COSTATUM WITH THE DESCRIPTION OF S. GREVILLEI SP. NOV.1
Authors: Zingone Adriana , Percopo Isabella , Sims Pat A. , Sarno Diana
Published: February 2005

The type material of Skeletonema costatum (Greville) Cleve was reexamined with the aims of providing an EM description of the species and clarifying which of the recently recognized Skeletonema Greville species, if any, deserves the epithet costatum. Two permanent mounts and two loose samples from the same collections from Hong Kong Bay were examined. Two distinct Skeletonema species were found in all materials. Based on the original description and on the observation of the lectotype, it was concluded that the most abundant morph in the type material is S. costatum. Cells were heavily silicified and 5–16 μm in diameter. The external processes of the fultoportulae in the terminal valves were open tubules with claw‐shaped tips. The intercalary fultoportulae processes were closed flattened tubules with a pore at their base, each attached to two processes of the sibling valve (1:2 junction). The rimoportula had a long process and was located marginally in all valves. The second morph in the type material was described as Skeletonema grevillei Sarno et Zingone sp. nov. Cells were delicate, 4–7.5 μm in diameter, and formed short colonies. The fultoportulae processes in the terminal valves were open tubes having narrow tips with truncated or spiny margins. In the intercalary valves, they formed knuckle‐like generally 1:1 junctions. A scallop‐work of silica bridges joined the bases of the processes. The rimoportula was marginal in all valves. Neither S. costatum nor S. grevillei match any Skeletonema species that have been recently analyzed by combined morphological and molecular approaches.