bluuebunny/crossref_metadata_2025 huggingface dataset:
Buffering of stable RNA promoter activity against DNA relaxation requires a far upstream sequence
Authors: Rochman Mark , Blot Nico , Dyachenko Marina , Glaser Gad , Travers Andrew , Muskhelishvili Georgi
Published: December 2004

The stable RNA promoters of Escherichia coli are exquisitely sensitive to variations in the superhelical density of DNA. Previously, we have shown that binding of the DNA architectural protein FIS at the upstream activating sequences (UASs) of stable RNA promoters prevents the transcription complexes from inactivation induced by changes in the supercoiling level of DNA. Here, we identify a strong FIS binding site 89 bp upstream of the previously described cluster of FIS binding sites located between positions −64 and −150 in the rrnA P1 UAS. Binding of FIS to this ‘far upstream sequence’ allows the recruitment of additional FIS molecules to the region. We demonstrate that, upon DNA relaxation, the maintenance of promoter activity requires, in addition to UAS, the presence of the far upstream sequence. The far upstream sequence shows no effect in the absence of an intact cluster. This requirement for the integrity of the region encompassing the far upstream sequence and the UAS cluster is correlated with the in vitro modulation of binding of FIS to UAS and interaction of RNA polymerase with the UP element and the region around the transcriptional start point. Our results suggest that, at the rrnA P1 promoter, the entire region comprising the UAS and the far upstream sequence is involved in the assembly of the transcription initiation complex. We propose that the extensive engagement of upstream DNA in this nucleoprotein complex locally compensates for the lack of torsional strain in relaxed DNA, thus increasing the resistance of the promoter to global DNA relaxation.
A novel anti‐anti‐activator mechanism regulates expression of the Pseudomonas aeruginosa type III secretion system
Authors: Dasgupta Nandini , Lykken Guinevere L. , Wolfgang Matthew C. , Yahr Timothy L.
Published: December 2004

Expression of the Pseudomonas aeruginosa type III secretion system (TTSS) is coupled to the secretion status of the cells. Environmental signals such as calcium depletion activate the type III secretion channel and, as a consequence, type III gene transcription is derepressed. Two proteins, ExsA and ExsD, were shown previously to play a role in coupling transcription to secretion. ExsA is an activator of TTSS gene transcription, and ExsD is an anti‐activator of ExsA. In the absence of environmental secretion cues, ExsD binds ExsA and inhibits transcription. Here, we describe the characterization of ExsC as an anti‐anti‐activator of TTSS expression. Transcription of the TTSS is repressed in an exsC mutant and is derepressed upon ExsC overexpression. The dependence on exsC for transcription is relieved in the absence of exsD, suggesting that ExsC and ExsD function together to regulate transcription. Consistent with this idea, ExsC interacts with ExsD in bacterial two‐hybrid and co‐purification assays. We propose a model in which the anti‐anti‐activator (ExsC) binds to and sequesters the anti‐activator (ExsD) under low Ca2+ conditions, freeing ExsA and allowing for transcription of the TTSS. The P. aeruginosa system represents the first example of an anti‐activator/anti‐anti‐activator pair controlling transcription of a TTSS.
Ageing and exposure to oxidative stressin vivodifferentially affect cellular levels of PrPcin mouse cerebral microvessels and brain parenchyma
Authors: Williams W. M. , Stadtman E. R. , Moskovitz J.
Published: December 2004

The biological function of cellular prion protein PrPchas not been established, despitein vitrostudies suggesting antioxidant activity or link to signal transduction pathways. In this study, mice were exposed to hyperoxia to establish whether oxidative stress affected prion expressionin vivo. C57Bl/6J mice aged 6, 18, and 24 months, maintained under normoxic conditions, exhibited age‐related increases in PrPcin both cerebral microvessels and in microvessel‐depleted brain homogenate. We demonstrate that PrPcis differentially affected by exposure to hyperoxiain vivofor 1 (24 h) or 2 (48 h) days, or for 1 day hyperoxia, followed by 1 day normoxia. Brain parenchymal cells from 6‐month‐old mice exposed to 1 day hyperoxia showed elevation of a glycosylated ∼36 kDa form, whereas in 24‐month‐old mice cellular prion level was substantially reduced. Extending hyperoxia from 1 to 2 days resulted in significantly reduced PrPclevel, regardless of age. Parenchymal PrPcis substantially elevated in 6‐month‐old mice, but declines in 18‐ and 24‐month‐old animals following 1 day hyperoxia. By contrast, PrPccontent in cerebral microvessels from 6‐month‐old mice declined after a 2 day exposure to hyperoxia, while microvessels from 24‐month‐old brains showed elevated prion levels 24 h after hyperoxia. Moreover, unglycosylated 25–30 kDa PrPc, and a previously undescribed 50–64 kDa band containing at least some glycosylated protein, predominated in microvessels with lesser content of the glycosylated ∼36 kDa form. Cellular content of these unglycosylated forms was correlated with age, while the response to hyperoxia was evident in both unglycosylated and glycosylated forms of the protein following 1 and 2 day exposures. The observed elevation of the 25–30 and 50–64 kDa bands of microvessel PrPcis not sustainable following 1 day hyperoxia, but returns to near normoxic levels within 24 h after hyperoxia. We also show in a knockout mouse for methionine sulfoxide reductase (MsrA), the enzyme responsible for reducing methionine sulfoxide back to methionine, and a regulator of cellular antioxidant defence, that following hyperoxia brain PrPcin the null mutant is elevated relative to PrPccontent in the parent strain. Our results show up‐regulated PrPcexpression or reduced turnover in response to age‐related, and hyperoxia‐induced oxidative stress.
Selective PrP‐like protein, doppel immunoreactivity in dystrophic neurites of senile plaques in Alzheimer's disease
Authors: Ferrer I. , Freixas M. , Blanco R. , Carmona M. , Puig B.
Published: December 2004

Doppel (Dpl) is a prion‐like protein encoded by the gene PRND, which has been found downstream of the prion gene PRNP in several species. The present study examines by immunohistochemistry Dpl expression in brain samples from 10 patients with Alzheimer's disease (AD), three patients with Pick's disease, four patients with Parkinson's disease, eight patients with diffuse Lewy body disease (DLBD), six patients with sporadic Creutzfeldt–Jakob disease (CJD) methionine/methionine at the codon 129, two patients with sporadic CJD methionine/valine at the codon 129 and numerous kuru plaques in the cerebellum, one patient with fatal familial insomnia (FFI), and 10 age‐matched controls. In the adult human brain, Dpl immunoreactivity was restricted to scattered granule cells of the cerebellum and scattered small granules in the cerebral cortex. Dpl immunoreactivity was seen around βA4 amyloid deposits in neuritic plaques, but not in diffuse plaques, AD and the common form of DLBD. Neurofibrillary tangles, Pick bodies and Lewy bodies were not stained with anti‐Dpl antibodies. No modifications in Dpl immunoreactivity were observed in CJD excepting those associated with accompanying senile plaques. No Dpl‐positive deposits were seen in FFI. Whether Dpl in neuritic plaques may attenuate amyloid‐induced oxidative stress and participate in the glial response around amyloid cores is discussed in light of the few available data on Dpl functions.
Frontotemporal lobar degeneration and ubiquitin immunohistochemistry
Authors: Josephs K. A. , Holton J. L. , Rossor M. N. , Godbolt A. K. , Ozawa T. , Strand K. , Khan N. , Al‐Sarraj S. , Revesz T.
Published: December 2004

We set out to determine the frequency of the different pathologies underlying frontotemporal degeneration (FTD) in our brain bank series, by reviewing all cases of pathologically diagnosed FTD over the last 12 years. We identified and reviewed 29 cases of FTD and classified them using the most recent consensus criteria with further histological analysis of 6 initially unclassifiable cases. Detailed histological analysis of these 6 cases revealed variable numbers of ubiquitin‐positive (tau and α‐synuclein‐negative) inclusions in 5 cases, consistent with the diagnosis of frontotemporal lobar degeneration with ubiquitin‐only‐immunoreactive neuronal changes (FTLD‐U). As a consequence of the current re‐evaluation, 18 (62%) of the 29 cases with FTD have underlying pathology consistent with FTLD‐U. Therefore in our brain bank series of frontotemporal degeneration, most cases were non‐tauopathies with FTLD‐U accounting for 62% of all the diagnoses.
Limb‐girdle muscular dystrophies – from genetics to molecular pathology
Authors: Laval S. H. , Bushby K. M. D.
Published: December 2004

The limb‐girdle muscular dystrophies are a diverse group of muscle‐wasting disorders characteristically affecting the large muscles of the pelvic and shoulder girdles. Molecular genetic analyses have demonstrated causative mutations in the genes encoding a disparate collection of proteins involved in all aspects of muscle cell biology. Muscular dystrophy includes a spectrum of disorders caused by loss of the linkage between the extracellular matrix and the actin cytoskeleton. Within this are the forms of limb‐girdle muscular dystrophy caused by deficiencies of the sarcoglycan complex and by aberrant glycosylation of α‐dystroglycan caused by mutations in the fukutin‐related protein gene. However, other forms of this disease have distinct pathophysiological mechanisms. For example, deficiency of dysferlin disrupts sarcolemmal membrane repair, whilst loss of calpain‐3 may exert its pathological influence either by perturbation of the IκBα/NF‐κB pathway, or through calpain‐dependent cytoskeletal remodelling. Caveolin‐3 is implicated in numerous cell‐signalling pathways and involved in the biogenesis of the T‐tubule system. Alterations in the nuclear lamina caused by mutations in laminA/C, sarcomeric changes in titin, telethonin or myotilin at the Z‐disc, and subtle changes in the extracellular matrix proteins laminin‐α2 or collagen VI can all lead to a limb‐girdle muscular dystrophy phenotype, although the specific pathological mechanisms remain obscure. Differential diagnosis of these disorders requires the careful application of a broad range of disciplines: clinical assessment, immunohistochemistry and immunoblotting using a panel of antibodies and extensive molecular genetic analyses.
Mimicry and the evolution of premating isolation in Heliconius melpomene Linnaeus
Authors: Jiggins C. D. , Estrada C. , Rodrigues A.
Published: December 2004

Ecological divergence can cause speciation if adaptive traits have pleiotropic effects on mate choice. In Heliconius butterflies, mimetic patterns play a role in mate detection between sister species, as well as signalling to predators. Here we show that male butterflies from four recently diverged parapatric populations of Heliconius melpomene are more likely to approach and court their own colour patterns as compared with those of other races. A few exceptions, where males were more attracted to patterns other than their own, suggest that some mimetic patterns are sub-optimal in mate choice. Genotype frequencies in hybrid zones between races of H. melpomene suggest that mating is random, so reinforcement is unlikely to have played a role in intra-specific divergence. In summary, co-evolved divergence of colour pattern and mate preference occurs rapidly and is likely the first step in Heliconius speciation.
Social group size, potential sperm competition and reproductive investment in a hermaphroditic leech, Helobdella papillornata (Euhirudinea: Glossiphoniidae)
Authors: Tan G. N. , Govedich F. R. , Burd M.
Published: December 2004

Social group size may affect the potential for sperm competition, and this in turn may favour ontogenetic adjustments in testicular mass according to the likely requirements for sperm and spermatophore production. In a number of comparative analyses of testis mass among vertebrate species that differ in mating system or social organization, increasing potential for sperm competition is associated with larger testis size. Intraspecific phenotypic plasticity should be able to produce the same pattern if social group size is heterogenous and reflects differing degrees of average sperm competition, but this intraspecific effect is less well studied. We tested the effect of social groups on both male and female investment in the simultaneously hermaphroditic leech, Helobdella papillornata. Leeches were placed in groups of one, two, four or eight. Sexual investment at the onset of reproductive maturity was quantified as the total testisac volume for male function and total egg volume for female function. We found that testisac volume (statistically adjusted for body size) showed a significant increase with increasing group size. Total egg volume (also adjusted for body size) was unaffected by group size. Our findings indicate adaptive developmental plasticity in male gonad investment in response to the potential for sperm competition.
Parasitism, host immune defence and dispersal
Authors: Møller A. P. , Martín-Vivaldi M. , Soler J. J.
Published: December 2004

Host-parasite interactions have been hypothesized to affect the evolution of dispersal by providing a possibility for hosts to escape debilitating parasites, and by influencing the level of local adaptation. We used a comparative approach to investigate the relationship between a component of host immune function (which reflects the evolutionary history of parasite-induced natural selection) and dispersal in birds. We used a sample of 46 species of birds for which we had obtained field estimates of T-cell response for nestlings, mainly from our own field studies in Denmark and Spain. Bird species with longer natal, but not with longer breeding dispersal distances had a stronger mean T-cell-mediated immune response in nestlings than species with short dispersal distances. That was also the case when controlling for the potentially confounding effect of migration from breeding to wintering area, which is known from previous studies to be positively associated with dispersal distance. These relationships held even when controlling for similarity among species because of common ancestry. Avian hosts with a larger number of different breeding habitats had weaker mean T-cell-mediated immune responses than habitat specialists. This relationship held even when controlling for similarity among species because of common ancestry. Therefore, T-cell-mediated immunity is an important predictor of evolutionary changes in dispersal ability among common European birds.
Evolutionary dynamics of a B chromosome invasion in island populations of the grasshopper Eyprepocnemis plorans
Authors: Riera L. , Petitpierre E. , Juan C. , Cabrero J. , Camacho J. P. M.
Published: December 2004

Four natural populations of the grasshopper Eyprepocnemis plorans in the Mallorca island were analysed for several years revealing the recent invasion of the B1 chromosome from the south-west part of the island (Palma region) towards the north and to the east. In only 10 years, the mean number of Bs in the northern population at Pollença increased from 0.053 to 0.692. Therefore, B chromosome invasion seems to be very rapid and has recently arrived to the north of the island. The south-west (close to Palma) is the most likely point at which B invasion started in the Mallorca Island. Finally, the number of B chromosomes was significantly associated to an increase in chiasma frequency (and thus recombination) in A chromosomes.
Nonlinear relationships and phylogenetically independent contrasts
Authors: Quader S. , Isvaran K. , Hale R. E. , Miner B. G. , Seavy N. E.
Published: December 2004

The method of phylogenetically independent contrasts is commonly used for exploring cross-taxon relationships between traits. Here we show that this phylogenetic comparative method (PCM) can fail to detect correlated evolution when the underlying relationship between traits is nonlinear. Simulations indicate that statistical power can be dramatically reduced when independent contrasts analysis is used on nonlinear relationships. We also reanalyse a published data set and demonstrate that ignoring nonlinearity can affect biological inferences. We suggest that researchers consider the shape of the relationship between traits when using independent contrasts analysis. Alternative PCMs may be more appropriate if data cannot be transformed to meet assumptions of linearity.
Mutation-selection balance accounting for genetic variation for viability in Drosophila melanogaster as deduced from an inbreeding and artificial selection experiment
Authors: Rodríguez-Ramilo S. T. , Pérez-Figueroa A. , Fernández B. , Fernández J. , Caballero A.
Published: December 2004

We carried out an experiment of inbreeding and upward artificial selection for egg-to-adult viability in a recently captured population of Drosophila melanogaster, as well as computer simulations of the experimental design, in order to obtain information on the nature of genetic variation for this important fitness component. The inbreeding depression was linear with a rate of 0.70 ± 0.11% of the initial mean per 1% increase in inbreeding coefficient, and the realized heritability was 0.06 ± 0.07. We compared the empirical observations of inbreeding depression and selection response with computer simulations assuming a balance between the occurrence of partially recessive deleterious mutations and their elimination by selection. Our results suggest that a model assuming mutation-selection balance with realistic mutational parameters can explain the genetic variation for viability in the natural population studied. Several mutational models are incompatible with some observations and can be discarded. Mutational models assuming a low rate of mutations of large average effect and highly recessive gene action, and others assuming a high rate of mutations of small average effect and close to additive gene action, are compatible with all the observations.
Predation and the persistence of melanic male mosquitofish (Gambusia holbrooki)
Authors: Horth L.
Published: December 2004

The empirical reasons for the persistent rarity of a genotype are typically complex and tedious to identify, particularly in nature. Yet rare morphs occur in a substantial fraction of phenotypic polymorphisms. A colour polymorphism has persisted for decades in the eastern mosquitofish, yet why this is so remains obscure. Here, I report the results of (1) intensive sampling at 45 natural sites to obtain the frequency distribution of the melanic (black) mosquitofish morph in Florida, (2) predation trials, conducted independently in mesocosms, with three different predatory species and (3) two mark-recapture studies, conducted in nature. This work (1) documents the rarity of melanic mosquitofish in nature, (2) demonstrates that melanic males experience a selective advantage over silver males in the presence of predators, (3) indicates no difference in the colour morphs‘ survival at a natural site essentially devoid of these predators, although suggesting a higher rate of recapture for melanic males at a site rife with predators. Overall, selective predation appears to contribute to the persistence of the melanic morph, despite its rarity in nature.
Effect of thyroliberin on the course of experimental candidosis in mice
Authors: Błaszkowska J. , Pawlikowski M. , Komorowski J. , Kurnatowski P.
Published: December 2004

Thyroliberin (TRH) is one of the hormones, which affect immunologic processes. This hormone was studied in experimental subacute candidosis in mice. BALB/c males were given intraperitoneally single dose of Candida albicans cells (1 × 107 to 1 × 109 cfu of strain no. 244–33 ATCC). The animals from the experimental groups were injected subcutaneously, after 24 h from inoculation, dose of 10 μg TRH in 0.2 ml 0.9% NaCl, seven times at 24 h intervals. The control animals were given respectively 0.2 ml of physiologic NaCl solution. We have found that the examined hormone significantly decreases mortality in these animals (LD50C. albicans for mice treated with TRH was three times higher than that in the control groups), prolongs mean survival time for mice and decreases the intensity of fungal invasion of the animal organs.
Cryptococcal meningitis in two apparently immunocompetent Maltese patients
Authors: Vella Zahra L. , Mallia Azzopardi C. , Scott G.
Published: December 2004

Two cases of cryptococcal meningitis occurring in immunocompetent men are described. The first case involves a farmer in whom cryptococcal meningitis was rapidly diagnosed using direct microscopy, latex antigen tests and culture of cerebrospinal fluid (CSF). In the second case, initial mycological tests on CSF (direct microscopy and culture) were repetitively negative and latex antigen tests gave unconvincing results. The patient was started on triple antituberculosis therapy, on which he improved immediately; therapy was continued for 1 year with the patient remaining well. However, within 1 week of stopping therapy, he had to be readmitted with neurological signs and symptoms. Culture of CSF this time yielded Cryptococcus neoformans and the antigen test was consistently positive. These are the first reported cases of cryptococcal meningitis in immunocompetent patients in Malta.
Painful jaundice revealing Kawasaki disease in a young man
Authors: GRANEL BRIGITTE , SERRATRICE JACQUES , ENE NICOLETA , IGUAL JEAN‐PIERRE , HABIB GILBERT , DISDIER PATRICK , WEILLER PIERRE‐JEAN
Published: December 2004

Abstract  Liver involvement is usually a minor manifestation of Kawasaki disease and includes hepatobiliary dysfunction or gallbladder hydrops. We describe here an unusual case of jaundice revealing an adult onset Kawasaki disease. An 18‐year‐old man presented with abdominal pain and jaundice associated with cholestasis as the initial manifestation of Kawasaki disease. Abdominal evaluation (ultrasonography and CT‐scan) did not find abnormality. Other signs typical of the Kawasaki disease occurred a few days later and permitted diagnosis. With aspirin and intravenous immunoglobulins, outcome was favorable without any cardiovascular complication. Our case suggests that Kawasaki disease should be added to the etiological list of painful febrile icterus in young patients.
Use of imidazole‐based eradication regimens for Helicobacter pylori should be abandoned in North India regardless of in vitro antibiotic sensitivity
Authors: BHATIA VIKRAM , AHUJA VINEET , DAS BIMAL , BAL CHANDRASEKHAR , SHARMA MAHESH P
Published: December 2004

Background and Aim:  The purpose of this study was to compare the efficacy of tinidazole‐ versus clarithromycin‐based triple regimens for eradication of Helicobacter pylori in North Indian patients of peptic ulcer disease, and to correlate the outcome with in vitro antibiotic susceptibility.

Methods:  One hundred and forty‐six H. pylori‐infected patients with active ulcer were included in the prospective, randomized study. A total of 70 patients received lansoprazole 30 mg b.d., amoxycillin 1000 mg b.d. and tinidazole 500 mg b.d. (LAT), and 76 patients received lansoprazole 30 mg b.d., amoxycillin 1000 mg b.d. and clarithromycin 500 mg b.d. (LAC) for 14 days. The H. pylori status was assessed by urea breath test, rapid urease test, and histology and antibiotic sensitivity pattern by Epsilometer test.

Results:  In per‐protocol analysis of 112 patients the H. pylori eradication rate was 42.3% (95% confidence interval (CI): 0.29–0.56) in LAT, and 64.8% (95%CI: 0.52–0.78) in LAC (95%CI of difference of proportions: 0.13–0.33, P = 0.01). Ulcer healed in 69.2% in the LAT group (95%CI: 0.57–0.82) and 81.7% in the LAC group (95%CI: 0.72–0.92; P = 0.02). Antibiotic susceptibility testing was done in 31 patients. Metronidazole resistance was present in 41.9% isolates but was unrelated to the outcome of the LAT regimen.

Conclusion:  Imidazole‐based eradication regimens should be abandoned in North India regardless of in vitro susceptibility results.
Hepatitis B virus infection after renal transplantation in the presence of antibody to hepatitis B surface antigen immunity
Authors: KIM KYUN‐HWAN , AHN SANG HOON , CHUNG HYO YOUNG , PAIK YONG HAN , Lee KWAN SIK , KIM YU SEUN , CHON CHAE YOON , MOON YOUNG MYOUNG , HAN KWANG‐HYUB
Published: December 2004

Background and Aim: Hepatitis B virus (HBV) infection has been known to be hampered by immunity against hepatitis B surface antigen (HBsAg). However, HBV with mutations within the common antigenic epitope of HBsAg, the ‘a’ determinant region, can escape from humoral immunity. Moreover, HBV infection by ‘a’ determinant mutants in chronic HBV patients has been reported after renal transplantation. In the present study, the authors investigated HBV infection after renal transplantation despite passive immunization or resolved HBV infection.

Methods: A total of 1682 patients who underwent a renal transplant between 1979 and 1998 at the Severance Hospital, Yonsei University College of Medicine, Korea, were enrolled. The sequence of the HBV genome was analyzed from two patients with antibody to HBsAg (anti‐HBs) immunity.

Results: Of 1682 patients who were HBsAg negative before transplantation, 21 patients were found to be HBsAg positive, with elevated aspartate aminotransferase and alanine aminotransferase levels after transplantation. Interestingly, six of 21 (28.6%) patients were anti‐HBs positive before the transplantation. Sequence analysis of the cloned HBV from two of six patients with anti‐HBs immunity showed no evidence of significant mutations within the ‘a’ determinant region, suggesting a wild‐type of HBV. Their donors were not exposed to HBV before transplantation (all HBV markers were negative). Seven deaths of 21 patients were ascribed to HBV‐related complications.

Conclusions: Regardless of anti‐HBs immunity, HBV infection occurred in immunosuppressed patients in a high endemic area. The molecular mechanism and clinical impact of HBV infection after renal transplantation in patients with anti‐HBs immunity should be further reappraised.

© 2004 Blackwell Publishing Asia Pty Ltd
Optimal treatment strategy for elderly patients with hepatocellular carcinoma
Authors: DOHMEN KAZUFUMI , SHIRAHAMA MASAFUMI , SHIGEMATSU HIROHISA , IRIE KOJI , ISHIBASHI HIROMI
Published: December 2004

Background and Aims:  The age distribution of patients with hepatocellular carcinoma (HCC) now peaks at nearly 70 years in Japan and this is continually increasing. Whether such elderly patients with HCC aged 80 years or older should be treated, and if so, how they should be selected for treatment remains uncertain. The present study was undertaken to determine any differences in the clinical characteristics and prognostic features between patients with HCC aged 80 years or older and those younger than 80 years of age. We also aimed to identify any significant variables in the prognosis of elderly patients with HCC aged 80 years or older.

Methods:  Seven hundred and four patients with HCC, diagnosed during a 12‐year period from January 1989 to December 2000, were categorized into two groups as follows: (i) 36 patients aged 80 years or older at the detection of HCC were defined as the elderly group and; (ii) 668 patients younger than 80 years of age were placed in the non‐elderly group. Clinical variables were analyzed and compared between the two groups, and any significant variables in the prognosis were simultaneously determined.

Results:  Regarding sex, viral markers, concentration of serum alpha‐fetoprotein, diameter and number of tumors, Child's grade, presence of portal thrombosis, histology grade of HCC and any types of treatment, no significant difference was found between the two groups. The 1‐year and 3‐year survival rates in the elderly group (54.1 and 28.1%, respectively) were not significantly different from those in the non‐elderly group (69.9 and 43.2%, respectively; P = 0.1053). The only significant factor in the prognosis in the elderly group was the presence of portal thrombosis, although a Child's grade of B or C was almost a significant factor with a P‐value of 0.063. Tumor size measuring more than 3 cm in the greatest dimension, non‐solitary tumor, Child's grade of B or C, and the presence of portal thrombosis were all found to be prognostic factors in the non‐elderly group using a multivariate analysis.

Conclusions:  An advanced stage of HCC, not advanced age, influenced the survival rate in these elderly patients. Therefore, an optimal treatment strategy should be applied for elderly patients with HCC who demonstrate less prognostic factors in the same manner as that for non‐elderly patients.

© 2004 Blackwell Publishing Asia Pty Ltd
Reasons for creation of permanent ileostomy for the management of idiopathic chronic constipation
Authors: EL‐TAWIL AM
Published: December 2004

The aim of the present study was to examine the reasons for initiation of end ileostomy for management of intractable constipation over the last 35 years. A total of 62 patients with intractable constipation, on whom an end ileostomy was created during the period from 1966 to 2001, were recorded. The incidence of initiating a terminal ileostomy as a further surgical intervention to the total number of managed patients in examined studies varied from 2 to 25%. Preoperative unevaluated anal and rectal abnormalities formed the highest proportion compared with other reasons (65%, 40/62). A better understanding of the functional colonic and anorectal abnormalities may facilitate changes in surgical therapy.
Gastric emptying function changes in patients with thyroid cancer after withdrawal of thyroid hormone therapy
Authors: KAO PAN‐FU , LIN JEN‐DER , CHIU CHENG‐TANG , HSU HUI‐TING , SEE LAI‐CHU , TZEN KAI‐YUAN
Published: December 2004

Background: Hypothyroidism is commonly thought to cause decreased gastric emptying but is mostly associated with autoimmune disease. In the present study the gastric emptying function of thyroid cancer patients with severe hypothyroidism of short duration was evaluated with a radionuclide solid meal gastric emptying study.

Methods: Twenty‐two patients who had undergone surgical operation and131I ablation for thyroid cancer participated in solid meal gastric emptying studies before the withdrawal of thyroxine and then again 4 weeks after the withdrawal of thyroxine. Eleven patients had an additional gastric emptying study at 6 weeks after withdrawal of thyroxine. Gastric emptying curves and emptying parameters were calculated. Student's pairedt‐test was used for statistical analysis of data for all cases between the baseline and at 4 weeks after withdrawal. An additional repeated measureanovawith multiple comparisons was performed on data between baseline, 4 weeks and 6 weeks after withdrawal for the other 11 patients. AllPvalues presented are two‐tailed and the significance level is 0.05.

Results: Hypothyroidism status was confirmed by the marked change of the serum thyroxine and thyroid‐stimulating hormone 4 weeks and 6 weeks after withdrawal of the thyroxine replacement (P < 0.001). The gastric half‐emptying time and emptying rate changed significantly after short‐term severe thyroid hormone deficiency (P < 0.005). However, the length of the lag phase did not have a statistically significant change at 4 weeks or 6 weeks after withdrawal of the thyroxin replacement (P = 0.219 and 0.142).

Conclusions: Hypothyroidism following the withdrawal of the thyroxine replacement in thyroid cancer patients preparing for131I cancer work‐up can significantly prolong gastric half‐emptying time and emptying rate.
Complement regulatory proteins in normal human esophagus and esophageal squamous cell carcinoma
Authors: SHIMO KIMIHIRO , MIZUNO MOTOWO , NASU JUNICHIROU , HIRAOKA SAKIKO , MAKIDONO CHIHO , OKAZAKI HIROAKI , YAMAMOTO KAZUHIDE , Okada Hiroyuki , Fujita Teizo , SHIRATORI YASUSHI
Published: December 2004

Background:  Altered expression of three complement regulatory proteins, decay‐accelerating factor (CD55), membrane cofactor protein (CD46) and homologous restriction factor 20 (CD59) has been identified in human gastrointestinal malignancies, but their expression in esophageal cancer has not been described. Therefore the purpose of the present paper was to study the distribution of these proteins in human normal and malignant esophageal mucosa.

Methods and results:  In the normal esophageal mucosa, CD55 predominantly stained on the cell membrane of squamous epithelium in the superficial and prickle cell layers, whereas CD46 most intensely stained on the cell membrane in the basal and parabasal cell layers. In contrast to this reciprocal expression of CD55 and CD46, CD59 was broadly distributed on the cell membrane in all layers. In the esophageal squamous cell carcinoma, CD55 staining was intense in the stroma but was negligible in the cancer cells. In contrast, CD46 and CD59 stained almost uniformly on the tumor cell membrane. There was a significant difference in the intensity of the staining of CD55 and CD46 among cells in various layers of normal esophageal mucosa and esophageal carcinoma cells, but not in the staining of CD59. Similar expression patterns of the three complement regulatory proteins in carcinoma cells and in normal epithelium in the basal and parabasal cell layers were observed.

Conclusions:  These observations on the expression of the three complement regulatory proteins would help understanding of the host immune responses involving the complement system against esophageal squamous cell carcinoma.
Postbiopsy intramural hematoma of the duodenum in an adult with Noonan's syndrome
Authors: SGOUROS SPIROS N , KARAMANOLIS GEORGE , PAPADOPOULOU EUTHIMIA , PAPAGEORGIOU GEORGE , STEFANIDES GERASIMOS , NASTOS HELIAS , MANTIDES APOSTOLOS
Published: December 2004

Abstract  Intramural duodenal hematoma is a rare complication of endoscopic biopsy. It is usually seen in children with growth failure and in patients with bleeding disorders or who are anticoagulated. It is frequently associated with acute pancreatitis. We present a case of an adult patient with Noonan's syndrome who developed postbiopsy intraduodenal hematoma. Abdominal ultrasound and computed tomography scan established the diagnosis. Conservative treatment was successful. According to a brief review of the literature, patients with Noonan's syndrome may develop hematoma after sampling of the duodenum because they present all the main predisposing factors. Additionally, pulmonic valve stenosis may be another predisposing factor, but this may warrant further investigation.
Genetic and phenotype changes following in vitro interactions between Helicobacter pylori strains
Authors: YAKOOB JAVED , FAN XUEGONG , HU GUOLING , ZHANG ZHENG
Published: December 2004

Background:  The purpose of the present paper was to determine whether in vitro interaction between different Helicobacter pylori strains leads to changes in antibiotic susceptibility, cagA, vacAM2 and DNA fingerprint patterns.

Methods:  Three H. pylori strains with known antibiotic susceptibility, cagA, vacAM2 status and polymerase chain reaction–random amplified polymorphic DNA (PCR‐RAPD) fingerprint analysis were suspended in phosphate buffered saline (PBS pH 7.0), and the suspensions were mixed in equal proportion prior to culture on chocolate agar plates. Subcultures were performed five times every 3 days. As a control, each of the three strains was also subcultured separately. Antibiotic susceptibility testing, PCR for cagA, vacAM2 and PCR‐RAPD analysis were done.

Results:  Surviving strain of the two H. pylori strains in each combination demonstrated change in resistance to both antibiotics but no change in sensitivity. CagA status of the surviving strain varied as compared to the vacAM2 status, which did not change. The PCR‐RAPD fingerprint showed unique band pattern.

Conclusion:  DNA transformation follows in vitro interaction. Helicobacter pylori strain with antibiotic resistance is likely to dominate in such in vitro interactions between various strains.
High viral load is a risk factor for hepatocellular carcinoma in patients with chronic hepatitis B virus infection
Authors: OHATA KAZUYUKI , HAMASAKI KEISUKE , TORIYAMA KAN , ISHIKAWA HIROKI , NAKAO KAZUHIKO , EGUCHI KATSUMI
Published: December 2004

Background and Aims:  Hepatitis B virus (HBV) is considered a major risk factor for the progression to liver cirrhosis and hepatocellular carcinoma (HCC). The serum level of HBV‐DNA is correlated with progression of the disease. The aim of the present study was to determine the relationship between the level of HBV‐DNA and hepatocarcinogenesis in patients with chronic HBV infection.

Methods:  The authors studied 73 patients who were diagnosed with chronic HBV infection at Nagasaki University Hospital (Nagasaki, Japan) between January 1980 and December 1999. The significance of age, sex, habitual drinking, serum alanine aminotransferase level, HBV viral load, interferon treatment, hepatic fibrosis and hepatic inflammation on the development of HCC were examined using univariate and multivariate analyses.

Results:  The cumulative incidence rates of HCC were 14%, 29% and 48% at 5, 10 and 15 years after liver biopsy, respectively. Multivariate analysis identified high viral load, together with age and severe fibrosis, as independent and significant risk factors (P = 0.045, 0.047 and 0.013, respectively) for HCC.

Conclusions:  The present findings indicate that high viral load is a risk factor for HCC in patients with chronic HBV infection. Patients with a high HBV viral load should be carefully monitored for HCC.
Cadherin/catenin complex appears to be intact in hepatocellular carcinomas from Australia and South Africa
Authors: HERATH NIRMITHA I , WALSH MICHAEL D , KEW MICHAEL C , YOUNG JOANNE , LEGGETT BARBARA A , MACDONALD GRAEME A
Published: December 2004

Background and Aim:  E‐cadherin binds to β‐catenin to form the cadherin/catenin complex required for strong cell adhesion. Inactivation of this complex in tumors facilitates invasion into surrounding tissues. Alterations of both proteins have been reported in hepatocellular carcinomas (HCC). However, the interactions between E‐cadherin and β‐catenin in HCC from different geographical groups have not been explored. The aim of the present study was to assess the role of E‐cadherin and β‐catenin in Australian and South African patients with HCC.

Methods:  DNA was extracted from malignant and non‐malignant liver tissue from 37 Australian and 24 South African patients, and from histologically normal liver from 20 transplant donors. Chromosomal instability at 16q22, promoter methylation at E‐cadherin, β‐catenin mutations and E‐cadherin and β‐catenin protein expression was assessed using loss of heterozygosity, methylation‐specific polymerase chain reaction, denaturing high‐performance liquid chromatography and immunohistochemistry, respectively.

Results:  Loss of heterozygosity at 16q22 was prevalent in South African HCC patients (50%vs 11%; P < 0.05, χ2). In contrast, E‐cadherin promoter hypermethylation was common in Australian cases in both malignant (30%vs 13%; P = not significant, χ2) and non‐malignant liver (57%vs 8%, respectively, P < 0.001, χ2). Methylation of non‐malignant liver was more likely to be detected in patients over the age of 50 years (P < 0.001, χ2), the overall mean age for our cohort of patients. Only one β‐catenin mutation was identified. E‐cadherin protein expression was reduced in one HCC, while abnormalities in protein expression were absent in β‐catenin.

Conclusion:  Contrary to previous observations in HCC from other countries, neither E‐cadherin nor β‐catenin appears to play a role in hepatocarcinogenesis in Australian and South African patients with HCC.
Effects of pravastatin and bezafibrate on biliary lipid excretion and hepatic expression of Abcg5 and Abcg8 in the rat
Authors: KAMISAKO TOSHINORI , OGAWA HIROSHI
Published: December 2004

Background and Aim:  Multidrug resistance associated gene product 2 (Mdr2) is believed to have a significant role in biliary cholesterol and phospholipid secretions. Both pravastatin and bezafibrate resulted in Mdr2 induction, but increased cholesterol secretion was observed only in pravastatin treatment. To explore the mechanism, the hepatic expression of genes that are responsible for the metabolism of the lipids was studied.

Methods:  Rats were divided into three experimental groups: (i) the control group; (ii) the bezafibrate group, which was fed a diet containing 0.45% bezafibrate for 5 days; and (iii) the pravastatin group, which was fed a diet containing 0.1% pravastatin for 5 days. Serum, hepatic and biliary lipids were measured by colorimetric assays and hepatic mRNA related to lipid metabolism was studied by reverse transcription–polymerase chain reaction (RT‐PCR).

Results:  In the bezafibrate group biliary phospholipid secretion was increased although cholesterol secretion was not increased. In the pravastatin group, biliary cholesterol and phospholipid secretions were significantly increased. The biliary cholesterol/phospholipid ratio was decreased in the bezafibrate group, but the ratio did not change in the pravastatin group. Hepatic Mdr2, Abcg5 and Abcg8 mRNA expression was remarkably increased in the pravastatin group in comparison with the control group (184%, 264% and 247% of control value, respectively). In the bezafibrate group the hepatic gene expression of Mdr2 was increased (157% of control value), but there were no significant changes in hepatic Abcg5 and Abcg8 mRNA expression compared with the control group.

Conclusions:  Compared with Mdr2, Abcg5 and Abcg8 seem to be more essential transporters for biliary secretion of cholesterol. Pravastatin upregulated Abcg5/Abcg8 while bezafibrate did not, which appears to explain the different effects of these compounds on biliary lipid secretion.

© 2004 Blackwell Publishing Asia Pty Ltd
Autonomic responses to heartburn induced by esophageal acid infusion
Authors: CHEN CHIEN‐LIN , ORR WILLIAM C
Published: December 2004

Background and Aim:  Studies have shown that altered visceral perception and lower pain thresholds in patients with symptomatic gastroesophageal reflux disease (GERD) and non‐cardiac chest pain. Autonomic changes associated with the perception of heartburn in patients with GERD are poorly understood.

Methods:  A total of 12 GERD patients (six male, six female; mean age 37.2 ± 2.7 years) and 12 controls (five male, seven female; mean age 32.8 ± 2.2 years) were studied. The study protocol included a 20‐min water infusion (6 mL/min), and 20‐min acid infusion (0.1 N HCl, 6 mL/min). Spectral analysis of heart‐rate variability (HRV) was used to assess autonomic functioning. The measured HRV indices included the power in the low‐frequency (LF) band (0.04–0.15 Hz) reflecting sympathetic tone, and power in the high‐frequency (HF) band (0.15–0.5 Hz) reflecting vagal tone, and the LF/HF ratio as an indicator of sympathovagal balance.

Results:  The GERD group experienced more heartburn than controls with acid infusion. Between‐group comparisons showed no significant changes in LF band power in any period. The HF band power was significantly lower in GERD patients during all infusion periods. The LF/HF ratio was significantly larger in GERD patients.

Conclusions:  The perception of heartburn induced by esophageal acid infusion is associated with a simultaneous increase in sympathetic modulation in patients with GERD. The autonomic responses with esophageal acid infusion are significantly different between healthy subjects and GERD patients.

© 2004 Blackwell Publishing Asia Pty Ltd
Induction of cholestasis in the perfused rat liver by 2‐aminoethyl diphenylborate, an inhibitor of the hepatocyte plasma membrane Ca2+ channels
Authors: GREGORY ROLAND B , HUGHES RACHAEL , BARRITT GREGORY J
Published: December 2004

Background and Aims:  An increase in the cytoplasmic free Ca2+ concentration in hepatocytes as a result of the release of Ca2+ from intracellular stores and Ca2+ inflow from the extracellular space is a necessary part of the mechanism by which bile acids are moved along the bile cannaliculus by contraction of the cannaliculus. 2‐Aminoethyl diphenylborate (2‐APB) is a recently discovered inhibitor of store‐operated plasma membrane Ca2+ channels in hepatocytes. The aim of the present study was to test the ability of 2‐APB to inhibit bile flow.

Methods:  Bile flow was measured in the isolated perfused rat liver using cannulation of the common bile duct. Measurements were carried out in the presence or absence of 2‐APB in either the presence of taurocholic acid (to enhance basal bile flow) or in the absence of taurocholic acid and in the presence of the hormones vasopressin and glucagon, which are known to stimulate bile flow.

Results:  In livers perfused in the presence of taurocholic acid, 2‐APB reversibly inhibited bile flow with a slow time of onset. The time of onset of inhibition was reduced by prior addition of the endoplasmic reticulum (Ca2+ + Mg2+)adenosine triphosphatase inhibitor, 2,5‐di‐t‐butylhydroquinone. In livers perfused in the absence of taurocholate, 2‐APB had little effect on the basal rate of bile flow, but inhibited the ability of vasopressin and glucagon to stimulate bile flow.

Conclusions:  It is concluded that an inhibitor of hepatocyte plasma membrane Ca2+ channels can induce cholestasis. The results provide evidence that suggests that, over a period of time, the normal function of hepatocyte store‐operated Ca2+ channels is required to maintain bile flow. Future strategies directed at the regulation of bile flow might include pharmacological or other interventions that modulate Ca2+ inflow to hepatocytes.
Distribution of type V secretory phospholipase A2 expression in human hepatocytes damaged by liver disease
Authors: ITO MASAMICHI , ISHIKAWA YUKIO , KIGUCHI HIDEKO , KOMIYAMA KAZUO , MURAKAMI MAKOTO , KUDO ICHIRO , AKASAKA YOSHIKIYO , ISHII TOSHIHARU
Published: December 2004

Background and Aim:  Type V secretory phospholipase A2 (sPLA2‐V) is a key enzyme in the arachidonate cascade. However, the distribution of sPLA2‐V in human liver has not yet been investigated. In this study, the significance of sPLA2‐V expression in human hepatocytes damaged by liver disease was investigated.

Methods:  Samples of liver tissue from patients with chronic hepatitis B and C, hepatitis virus‐related liver cirrhosis, and congestive hepatocyte injury were immunostained with antibodies against sPLA2‐V, cyclooxygenase (COX)‐2, hepatitis viral antigens, transforming growth factor (TGF)‐β1, interleukin (IL)‐1β and tumor necrosis factor (TNF)‐α.

Results:  In chronic hepatitis patients, sPLA2‐V‐positive hepatocytes were scattered in the liver lobules, while cyclooxygenase‐2, IL‐1β, and TNF‐α were diffusely expressed. Hepatocytes around necroinflammatory lesions were strongly positive for sPLA2‐V. Some sPLA2‐V‐positive hepatocytes were also positive for viral antigens. TGF‐β1 was expressed only in fibrotic lesions. The pattern of distribution of these proteins in liver cirrhosis patients was similar to that in chronic hepatitis patients, but sPLA2‐V expression tended to be more intense than in chronic hepatitis. In the congestive liver, sPLA2‐V, COX‐2, and the two cytokines were diffusely expressed in surviving hepatocytes.

Conclusions:  sPLA2‐V expression in hepatocytes is induced by viral infection, fibrosis, and circulatory disturbance. Immunostaining using sPLA2‐V antibody is useful for the detection of injured hepatocytes in patients with liver diseases.