bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a transformation and selection system for the glycolipid‐producing yeast Candida bombicola
Authors: Van Bogaert Inge N. A. , De Maeseneire Sofie L. , Develter Dirk , Soetaert Wim , Vandamme Erick J. 
Published: March 2008

AbstractSophorolipids are surface‐active compounds synthesized by the non‐pathogenic yeast Candida bombicola. Over recent decades much effort has been spent to optimize culture conditions in order to improve the yield and production process. As far as we know, however, hardly any attention has been given to the genetics of the producing yeast strain itself and there are no published results available on the genetic engineering of C. bombicola. Nevertheless, this can be a useful tool for the study of the sophorolipid synthesis pathway and open up perspectives for improved production. A first step is the development of a suitable transformation and selection method. This article describes the creation and selection of an uracil auxotrophic C. bombicola mutant, which can be transformed back to prototrophy with the species' own orotidine 5′‐phosphate decarboxylase or URA3 gene. Successful transformation was confirmed by a PCR‐based method discriminating between the wild‐type and mutated URA3 gene. Copyright © 2008 John Wiley & Sons, Ltd.
Homocysteine activates calcium‐mediated cell signaling mechanisms targeting the cytoskeleton in rat hippocampus
Authors: Loureiro Samanta Oliveira , Heimfarth Luana , Pelaez Priscila de Lima , Vanzin Camila Simioni , Viana Lilian , Wyse Angela T.S. , Pessoa‐Pureur Regina 
Published: March 2008

AbstractHomocysteine is considered to be neurotoxic and a risk factor for neurodegenerative diseases. Despite the increasing evidences of excitotoxic mechanisms of homocysteine (Hcy), little is known about the action of Hcy on the cytoskeleton. In this context, the aim of the present work was to investigate the signaling pathways involved in the mechanism of action of Hcy on cytoskeletal phosphorylation in cerebral cortex and hippocampus of rats during development. Results showed that 100 μM Hcy increased the intermediate filament (IF) phosphorylation only in 17‐day‐old rat hippocampal slices without affecting the cerebral cortex from 9‐ to 29‐day‐old animals. Stimulation of45Ca2+uptake supported the involvement of NMDA receptors and voltage‐dependent channels in extracellular Ca2+flux, as well as Ca2+release from intracellular stores through inositol‐3‐phosphate and ryanodine receptors. Moreover, the mechanisms underlying the Hcy effect on hippocampus cytoskeleton involved the participation of phospholipase C, protein kinase C, mitogen‐activated protein kinase, phosphoinositol‐3 kinase and calcium/calmodulin‐dependent protein kinase II. The Hcy‐induced IF hyperphosphorylation was also related to Giprotein and inhibition of cAMP levels. These findings demonstrate that Hcy at a concentration described to induce neurototoxicity activates the IF‐associated phosphorylating system during development in hippocampal slices of rats through different cell signaling mechanisms. These results probably suggest that hippocampal rather than cortical cytoskeleton is succeptible to neurotoxical concentrations of Hcy during development and this could be involved in the neural damage characteristic of mild homocystinuric patients.
Formulation of a strategy for the application of Duddingtonia flagrans to control caprine parasitic gastroenteritis
Authors: Sanyal P.K. , Sarkar A.K. , Patel N.K. , Mandal S.C. , Pal S. 
Published: March 2008

AbstractExperiments on the influence of egg density and varying quantities of chlamydospores on the nematode-trapping ability of Duddingtonia flagrans, influence of D. flagrans on the larval translation of gastrointestinal nematodes, doses of chlamydospores required for the effective control of gastrointestinal nematodosis and the epidemiology of nematode parasites were conducted in goats, which generated baseline data required for strategic application of the biocontrol agent. The nematode-trapping ability of D. flagrans, measured by numerical enumeration of infective third-stage larvae developed in the faecal culture, revealed that the efficacy is dependent on both nematode egg and chlamydospore density. Pasture plot studies revealed that D. flagrans, if deposited at the same time as nematode eggs, prevents translation of third-stage larvae of caprine nematodes from the faecal pats onto the grass blades. Feeding of 1 × 106 chlamydospores per kg body weight and above to goats virtually eliminated larvae from the pasture. Application of as few as 1 × 104 and 1 × 105 chlamydospores per kg body weight had a profound impact on larval recovery. The effect persisted as long as the chlamydospores were fed. Monthly faecal worm egg counts of adult goats maintained under a semi-intensive management system on the Chhattisgarh plain and pasture larval burden revealed that June to August were the months of high risk for nematodosis. Haemonchus was the dominant species recorded throughout the year. The present data can best be utilized by formulating a strategic control measure when the larval challenge to the animal is maximum (June to August), so as to prevent establishment of patent infection. The observations reinforced the strategy to be adopted for nematode parasite control in goats by applying the biocontrol option at the onset of the monsoon.
How will public and animal health interventions drive life-history evolution in parasitic nematodes?
Authors: LYNCH PENELOPE A. , GRIMM UWE , READ ANDREW F. 
Published: March 2008

SUMMARYInfection caused by parasitic nematodes of humans and livestock can have significant health and economic costs. Treatments aimed at alleviating these costs, such as chemotherapy and vaccination, alter parasite survival and reproduction, the main selective pressures shaping life-history traits such as age to maturity, size and fecundity. Most authors have argued that the life-history evolution prompted by animal and public health programmes would be clinically beneficial, generating smaller, less fecund worms, and several mathematical models support this view. However, using mathematical models of long-lasting interventions, such as vaccination, and regularly repeated short interventions, such as drenching, we show here that the expected outcome actually depends on how mortality rates vary as a function of worm size and developmental status. Interventions which change mortality functions can exert selection pressure to either shorten or extend the time to maturity, and thus increase or decrease worm fecundity and size. The evolutionary trajectory depends critically on the details of the mortality functions with and without the intervention. Earlier optimism that health interventions would always prompt the evolution of smaller, less fecund and hence clinically less damaging worms is premature.
A new class of isotropic generators for developing 6-DOF isotropic manipulators
Authors: Tsai K. Y. , Lee T. K. , Jang Y. S. 
Published: March 2008

SUMMARYDeveloping 6-DOF isotropic manipulators using isotropic generators is simple and efficient, and isotropic generators can be employed to develop serial, redundant, or parallel isotropic manipulators. An isotropic generator consists of a reference point and six straight lines. The existing generators, however, have one common geometric constraint: the reference point is equidistant from the six straight lines. Some practical isotropic designs might not be obtained due to this constraint. This paper proposes methods for developing new isotropic generators. The generators thus developed are not subject to the constraint, and the new methods allow us to specify the location of the tool center point, the size of the platform or the base, or the shape of isotropic parallel manipulators. Many new generators are presented to develop 6-DOF parallel manipulators with different shapes or different types of kinematic chains.
Inhalant abuse among adolescents: neurobiological considerations
Authors: Lubman D I , Yücel M , Lawrence A J 
Published: March 2008

Experimentation with volatile substances (inhalants) is common during early adolescence, yet limited work has been conducted examining the neurobiological impact of regular binge use during this key stage of development. Human studies consistently demonstrate that chronic use is associated with significant toxic effects, including neurological and neuropsychological impairment, as well as diffuse and subtle changes in white matter. However, most preclinical research has tended to focus on acute exposure, with limited work examining the neuropharmacological or toxicological mechanisms underpinning these changes or their potential reversibility with abstinence. Nevertheless, there is growing evidence that commonly abused inhalants share common cellular mechanisms, and have similar actions to other drugs of abuse. Indeed, the majority of acute behavioural effects appear to be underpinned by changes in receptor and/or ion channel activity (for example, GABAA, glycine and 5HT3receptor activation, NMDA receptor inhibition), although nonspecific interactions can also arise at high concentrations. Recent studies examining the effects of toluene exposure during the early postnatal period are suggestive of long‐term alterations in the function of NMDA and GABAAreceptors, although limited work has been conducted investigating exposure during adolescence. Given the critical role of neurotransmitter systems in cognitive, emotional and brain development, future studies will need to take account of the substantial neuromaturational changes that are known to occur in the brain during childhood and adolescence, and to specifically investigate the neuropharmacological and toxicological profile of inhalant exposure during this period of development.British Journal of Pharmacology(2008)154, 316–326; doi:10.1038/bjp.2008.76; published online 10 March 2008
Photodynamic activity of BAM‐SiPc, an unsymmetrical bisamino silicon(IV) phthalocyanine, in tumour‐bearing nude mice
Authors: Leung S C H , Lo P‐C , Ng D K P , Liu W‐K , Fung K‐P , Fong W‐P 
Published: March 2008

Background and purpose: Ever since the discovery of photodynamic therapy, there has been a continuous search for more potent photosensitizers. Towards that end, we have synthesized a number of novel phthalocyanine derivatives. The unsymmetrical bisamino silicon(IV) phthalocyanine BAM‐SiPc is one of the most potent compounds. In in vitro cell culture, it exhibits high phototoxicity against a number of cancer cell lines.Experimental approach: In the present investigation, the in vivo effect of BAM‐SiPc was studied in the tumour‐bearing nude mice model. The biodistribution of BAM‐SiPc was followed to evaluate its tumour selectivity and rate of clearance. The tumour volume in the hepatocarcinoma HepG2‐ and the colorectal adenocarcinoma HT29‐bearing nude mice was measured after photodynamic therapy. The level of intrinsic toxicity induced was also investigated. Finally, the metabolism of BAM‐SiPc in the ‘normal’ WRL68 liver cells and the hepatocarcinoma HepG2 cells was compared.Key results: The results not only showed significant tumour regression of HepG2 and growth inhibition of HT29 in the tumour‐bearing nude mice, but also no apparent hepatic or cardiac injury with the protocol used. Histological analyses showed that apoptosis was induced in the solid tumour. BAM‐SiPc could be metabolized by WRL68 liver cells but not by the hepatocarcinoma HepG2 cells. Unfortunately, BAM‐SiPc did not show any specific targeting towards the tumour tissue.Conclusions and implications: The efficiency of BAM‐SiPc in inhibiting tumour growth makes it a good candidate for further evaluation. Enhancement of its uptake in tumour tissue by conjugation with biomolecules is currently under investigation.
New approaches to the diagnosis of functional upper gut disease
Authors: Camilleri Michael 
Published: March 2008

AbstractFunctional upper gut symptoms, such as nausea, vomiting and abdominal pain, are a continuing challenge in gastroenterological practice. This article considers the approaches applied in recent years to evaluate motor function in the upper gut including manometry and radio‐nuclide transit studies, and symptom‐provocation tests such as balloon distension and pharmacologic stimulation.An approach is proposed that is based on positive symptomatic diagnosis of the disturbed pathophysiologic state, followed by treatment of this disturbance of function after a minimum of confirmatory investigations.
In vitro synthesis and immunoregulation of antibody to hepatitis B surface antigen in man
Authors: HANSON REGINALD G. , HOOFNAGLE JAY H. , COOKSLEY W. GRAHAM , JONES E. ANTHONY 
Published: March 2008

Abstract Peripheral blood mononuclear cells (PBMC) from 16 chronic hepatitis B surface antigen (HBsAg) carriers and from 10 immune individuals (anti‐HBs and/or anti‐HBc core antigen positive) were studied for their ability to synthesize antibody to hepatitis B viral antigens in vitro. Pokeweed mitogen (PWM)‐stimulated B lymphocytes from carriers, synthesized polyclonal IgG and IgM normally but did not synthesize detectable antibody to HBsAg (anti‐HBs) even in the presence of T lymphocyte help and the absence of T lymphocyte suppression from immune individuals. In contrast, B lymphocytes from 80% of immune individuals synthesized anti‐HBs in vitro. In cell‐mixing experiments, T lymphocytes from carriers were found to provide normal helper function for immunoglobulin and anti‐HBs production by B lymphocytes from immune individuals. In addition, the degree of suppressor T lymphocyte activity of chronic carriers was not sufficient to explain the lack of anti‐HBs production.The effect of purified HBsAg on anti‐HBs synthesis by PBMC from immune individuals was determined. Incubating PBMC for periods ranging from 10 min to 10 days in the presence of concentrations of HBsAg varying from 10 pg/ml to 10 μg/ml had no effect on the synthesis of anti‐HBs by PBMC. These results suggest that chronic HBsAg carriers lack circulating B lymphocytes capable of producing anti‐HBs and that this cannot be explained by the presence of large amounts of circulating HBsAg.
Gall‐bladder glycoprotein synthesis and secretion during cholesterol gallstone formation in the mouse
Authors: WHITING M. J. , WATTS J. MCK. 
Published: March 2008

AbstractGlycoprotein synthesis by the gall‐bladder was studied during cholesterol gallstone formation in mice fed a diet supplemented with 1% cholesterol and 0.5% cholic acid for up to 6 weeks. Within 1 week, this lithogenic diet induced a 5 fold increase in the cholesterol saturation of gall‐bladder bile, which remained near‐saturated for the next 5 weeks. Cholesterol gallstones were infrequent until the fourth week of the diet. Glycoprotein synthesis was measured as the incorporation of3H‐glucosamine by mouse gall‐bladder explants in organ culture and was found to double after 4 weeks of the diet when expressed per gall‐bladder. This increase could be explained by a marked enlargement of the gall‐bladder with a greater number of mucus‐secreting cells. Gall‐bladder glycoprotein synthesis and secretion did not appear to be regulated by prostaglandins, since indomethacin blocked prostaglandin synthesis but did not inhibit glycoprotein synthesis. High molecular weight mucin glycoprotein accounted for around one‐third of gall‐bladder glycoprotein secretion.These results are consistent with the hypothesis that gall‐bladder mucin acts as a nucleating agent for cholesterol crystal and gallstone formation. However, this mouse model for cholesterol gallstone formation is different from the prairie dog model, not only in dietary requirements, but also in the effect of the diet on the gall‐bladder, and possibly in the mechanism of regulation of gall‐bladder much glycoprotein synthesis.
Liver microvascular flow in rats: Quantitation by laser Doppler flowmetric technique and effects of sodium dehydrocholate
Authors: KOO ANTHONY 
Published: March 2008

ABSTRACTAn in vivo in situ liver preparation in anaesthetized male Sprague‐Dawley rats was devised for simultaneous measurements of hepatic microvascular flow and bile flow. The micro‐vascular flow on the surface of the liver was continuously recorded by laser Doppler flowmetric technique whilst bile flow was quantitated by connecting the bile duct cannula to a drop counter. Sodium dehydrocholate was infused (0.2 ml in 2–5 min) both via a cannula in the splenic artery and via a cannula in the superior mesenteric vein. Results showed that sodium dehydrocholate, given by either route, increased the liver microvascular flow and bile flow. A cross‐plot between the hyperaemic and hypercholeretic responses corresponding to the same dose of sodium dehydrocholate revealed a significant correlation (P < 0.01) between the sodium dehydro‐cholate‐induced hypercholeresis and hyperaemia. Furthermore, the increase of microvascular flow occurred significantly (P < 0.05) earlier than the hypercholeretic response. Results thus suggested that an increase of plasma blood flow was essential for the development of hypercholeresis induced by sodium dehydrocholate.
Metabolic activation of polycyclic aromatic hydrocarbons by human colonic mucosa and Bacteroides fragilis
Authors: TASICH M. , HAFNER L. , PIPER D. W. , STIEL D. 
Published: March 2008

Abstract The Ames Salmonella mutagenicity assay has been used to assess the metabolic activation of the following polycyclic aromatic hydrocarbons by human colonic microsomes (S9) and a cell‐free extract of Bacteroides fragilis (Bf): 2‐aminoanthracene, 1‐naphthylamine, 2‐naphthylamine, 2‐aminofluorene, 2‐acetylaminofluorene, anthracene, benzo(a)pyrene, 3‐methylcholanthrene, 7, 12‐dimethylbenzanthracene, acridine, 9‐aminoacridine and 3‐methylindole.2‐Aminoanthracene and 2‐aminofluorene were the only compounds activated. In both cases, activation was dose‐dependent and 2‐aminofluorene exhibited synergistic activation by S9+Bf, as has previously been demonstrated with 2‐aminoanthracene.The organospecific aliphatic colonic carcinogen, 1, 2‐dimethylhydrazine was not activated in this system. Metabolic activation by S9+Bf is thus restricted to aromatic compounds with three rings and an amino group in position 2.These findings are consistent with enzymic substrate specificity, and are compatible with an enzymic basis for activation of polycyclic aromatic hydrocarbons by B. fragilis, present in large concentrations in the colonic lumen, and colonic microsomes.
Serological survey on hepatitis A and B infections among the residents of social welfare homes in Singapore
Authors: LAM S. K. , QUAK S. H. , RAMAN G. V. , TEO J. , WONG H. B. , OON C. J. 
Published: March 2008

A study of the immunological status of hepatitis A and B infections was carried out among the residents of eight social welfare homes in Singapore. The sample population consisted of 440 individuals of whom 55% were Chinese, 21% were Malays and 24% were Indians. The mean age of the study population was 14 years and 4 months. The immunological markers studied included specific IgM antibody and total antibody against hepatitis A virus (anti‐HAV‐IgM and total anti‐HAV respectively); hepatitis B surface antigen (HBsAg), surface antibody (anti‐HBs), core antibody (anti‐HBc) and e antigen (HBeAg), all tested by the enzyme immunoassay (EIA) technique.While none of the subjects had detectable anti‐HAV‐IgM (HAVAB‐M‐EIA), 12% were positive for total anti‐HAV (HAVAB‐EIA) indicating evidence of past infection. HBsAg was detected (Auszyme II) in 4.5% and of these, half had HBeAg (Abbott‐HBe EIA). Anti‐HBs positivity (AUSAB‐EIA) occurred in 11.6% and the majority (88%) of these had anti‐HBc positivity (CORZYME) as well. The positive rate for anti‐HBc alone was 3.6% reflecting the ‘window’ period after the fall of HBsAg and before the rise of anti‐HBs. At least one of the hepatitis B markers was present in 19.1% of the study population.The endemic nature of both hepatitis A and B infections in the local population is evident, with infection occurring in all ethnic groups at an early age.
Fermentation in ileostomy bags: Control of excessive gas with diet, pH and antibiotics
Authors: GAFFNEY PHILIP T. , BUTTENSHAW RONALD L. , STILLMAN LENA , WARD MICHAEL 
Published: March 2008

The composition of early morning gas from the bags of 10 ileostomates was determined using gas chromatography. Seven of the 10 had a predominance of gases attributable to bacterial fermentation (H2 and CO2, 70 ± 12%). The remaining three contained mainly atmospheric gases, N2 and O2, with only small amounts of fermentation gases (7 ± 3%).When a controlled low fibre (0.7 g) dinner was substituted for a high fibre (13.5 g) evening meal, there was a corresponding decrease in the volume of fermentation gas in the ileostomy bag the next morning (P < 0.05).Gas production from ileostomy effluent was inhibited in vitro by 10 < pH < 5 and by antimicrobial agents. The most effective were metronidazole, chloramphenicol, tetracycline, erythromycin and chlorhexidine. These reduced fermentation gas by more than 95%.It was concluded that the majority of the gas produced by ileostomates is formed by bacterial fermentation of the faecal waste in their ileostomy bag and that this may be controlled by careful manipulation of their diet.
The effects of cisapride on gastric and oesophageal emptying in dystrophia myotonica
Authors: HOROWITZ MICHAEL , MADDOX ANNE , WISHART JUDITH , COLLINS PETER J. , SHEARMAN DAVID J. C. 
Published: March 2008

AbstractThe effects of cisapride on gastric emptying, oesophageal emptying, and gastrointestinal symptoms were evaluated in 10 patients with dystrophia myotonica who had delayed gastric emptying of the solid and/or liquid component of a meal. A double isotope technique was used to measure gastric emptying and oesophageal emptying was measured as the time taken for a bolus of the solid meal to enter the stomach. Gastrointestinal symptoms were assessed by a questionnaire. Gastric and oesophageal emptying and gastrointestinal symptoms were measured before and when each subject had taken cisapride (10 mg, q.i.d., p.o.) for 4 weeks. Cisapride improved solid gastric emptying, and there was a non‐significant trend for improved liquid emptying. Cisapride had no effect on oesophageal emptying. Upper gastrointestinal symptoms were less after cisapride and there was an increased frequency of bowel actions. No side effects were reported. These results indicate that gastroparesis is a treatable cause of morbidity in dystrophia myotonica.
Acute sporadic non‐A, non‐B viral hepatitis of adults in India—Epidemiological and immunological studies
Authors: DATTA RAKESH , PANDA S. K. , TANDON B. N. , MADANGOPALAN N. , BOSE S. L. , ACHARYA S. K. , NAYAK N. C. 
Published: March 2008

AbstractOn the basis of tests for specific IgM class antibodies in the serum, infections by hepatitis A virus, hepatitis B virus and hepatitis non‐A, non‐B virus accounted for 7%, 37.8% and 54.2% respectively of 286 cases of acute sporadic viral hepatitis in adults from three different regions of India. Epstein‐Barr virus and cytomegalo virus were insignificant (0.5–1%) aetiological agents. Approximately one‐quarter of all non‐A, non‐B (NANB) cases were additionally HBsAg carriers; there were significant differences in regional frequencies. NANB hepatitis commonly affected individuals in the mid‐fourth decade and occurred throughout the year with small peaks in different seasons. No antigen‐antibody reaction could be demonstrated in various immunological tests including radioimmunobinding using acute and convalescent phase sera. Neither were virus‐like particles visualized in acute phase sera on electron and immuno‐electron microscopy. However, rhesus monkeys inoculated with acute phase serum from a case of NANB hepatitis developed distinct hepatocellular changes at 43–55 days after inoculation, which had some features of similarity with experimental NANB hepatitis of other simian species. Sporadic NANB hepatitis is a major health problem throughout India and intensive study is needed on its epidemiology and aetiology.