bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association of mycothiol with protection of Mycobacterium tuberculosis from toxic oxidants and antibiotics
Authors: Buchmeier Nancy A. , Newton Gerald L. , Koledin Teresa , Fahey Robert C. 
Published: March 2003

SummaryMycothiol, MSH or 1d‐myo‐inosityl 2‐(N‐acetyl‐l‐cysteinyl)amido‐2‐deoxy‐α‐d‐glucopyranoside, is an unusual conjugate of N‐acetylcysteine (AcCys) with 1d‐myo‐inosityl 2‐acetamido‐2‐deoxy‐α‐d‐glucopyranoside (GlcN‐Ins), and is the major low‐molecular‐mass thiol in mycobacteria. Mycothiol has antioxidant activity as well as the ability to detoxify a variety of toxic compounds. Because of these activities, MSH is a candidate for protecting Mycobacterium tuberculosis from inactivation by the host during infections as well as for resisting antituberculosis drugs. In order to define the protective role of MSH for M. tuberculosis, we have constructed an M. tuberculosis mutant in Rv1170, one of the candidate MSH biosynthetic genes. During exponential growth, the Rv1170 mutant bacteria produced ≈ 20% of wild‐type levels of MSH. Levels of the Rv1170 substrate, GlcNAc‐Ins, were elevated, whereas those of the product, GlcN‐Ins, were reduced. This establishes that the Rv1170 gene encodes for the major GlcNAc‐Ins deacetylase activity (termed MshB) in the MSH biosynthetic pathway of M. tuberculosis. The Rv1170 mutant grew poorly on agar media lacking catalase and oleic acid, and had heightened sensitivities to the toxic oxidant cumene hydroperoxide and to the antibiotic rifampin. In addition, the mutant was more resistant to isoniazid, suggesting a role for MSH in activation of this prodrug. These data indicate that MSH contributes to the protection of M. tuberculosis from oxidants and influences resistance to two first‐line antituberculosis drugs.
Human duodenal phase III migrating motor complex activity is predominantly antegrade, as revealed by high‐resolution manometry and colour pressure plots
Authors: Andrews J. M. , O'donovan D. G. , Hebbard G. S. , Malbert C. H. , Doran S. M. , Dent J. 
Published: March 2003

Abstract
Late phase III migrating motor complex activity has been said to be primarily retroperistaltic but has not been assessed with high resolution manometry or three‐dimensional colour pressure plots (pressure/time/distance). Duodenal phase III was examined in healthy young volunteers (seven male, two female) with a 20‐lumen assembly. With the most proximal sidehole in the distal antrum, after a 4.5‐cm interval 18 sideholes at 1.5‐cm intervals spanned the duodenum with a final sidehole 3 cm beyond. Fasting pressures were recorded until phase III occurred. Comparisons were made between proximal (P) and distal (D) duodenum during early (E) (first 0.5–1 min) and late (L) (last 0.5–1 min) phase III. With colour pressure analysis, 121 of 180 pressure wave (PW) sequences were purely antegrade, two purely retrograde and 57 bidirectional. Ten of fifty‐seven bidirectional PW sequences were complex, branching to become two separate sequences. Bidirectional sequences occurred more frequently in late than early phase III (L 43 vs. E 14 of 57), but their occurrence did not differ between proximal and distal duodenum (P31 vs. D 24 of 57). Antegrade propagation velocity was faster in late compared with early phase III (L 28.50 vs. E 17.05 mm s−1; P = 0.006), but did not differ between proximal and distal duodenum. Colour pressure analysis also indicated an intermittent segmental pattern to phase III, with each subject exhibiting a change in velocity or direction, or a relative failure of peristalsis somewhere along the duodenum during part of phase III. Duodenal phase III is not homogenous and, in contrast with previous studies, does not primarily constitute a retroperistaltic pump. Colour pressure analysis is useful in interpreting intraluminal pressure profiles and may improve the sensitivity and specificity of clinical studies.
Neural integrity is essential for the propagation of colonic migrating motor complexes in the mouse
Authors: Powell A. K. , O'brien S. D. , Fida R. , Bywater R. A. R. 
Published: March 2003

Abstract
The mechanisms that underlie the propagation of contractions along the colon are uncertain. We have examined whether spontaneous colonic migrating motor complexes (CMMCs) migrate through a region of muscle paralysis, or through a region where neural transmission was disrupted in the isolated mouse colon. Mouse colon was mounted in a separately perfused three‐compartment organ bath and recordings of circular muscle tension were made. Drug application was restricted to the middle compartment. Application of nifedipine (1 µmol L−1), an l‐type calcium channel antagonist, reduced the contraction amplitude by ∼94%, without affecting the form of contractions in the proximal and distal compartments. Moreover, CMMCs appeared to remain temporally related in all compartments. In contrast, interruption of neural transmission in the middle compartment by either tetrodotoxin (1.6 µmol L−1), hexamethonium (500 µmol L−1) or a low‐calcium, high‐magnesium solution abolished CMMCs in this compartment; contractions recorded in the proximal and distal compartments became slower in frequency and were no longer synchronized. The experiments suggest that there may be more than one ‘pacemaker’ generating spontaneous CMMCs and that CMMCs can migrate through a region where there is minimal tension generation, but not through a region where neural integrity has been compromised.
Idiopathic slow transit constipation and megacolon are not associated with neurturin mutations
Authors: Chen B. , Knowles C. H. , Scott M. , Anand P. , Williams N. S. , Milbrandt J. , Tam P. K. H. 
Published: March 2003

Abstract
Chronic idiopathic slow‐transit constipation (ISTC) and idiopathic megacolon (IMC) are early‐onset gastrointestinal motility disorders of unknown aetiology. The gene encoding the neurotrophic factor neurturin may be a candidate for these disorders, as neurturin‐deficient mice have a similar enteric phenotype. In the present study, we tested this hypothesis. Genomic DNA from 26 cases of chronic idiopathic STC [with a family history of constipation in 15 (58%) and Hirschsprung's disease in two (8%)], and five cases of IMC [two familial (40%)] was screened by direct DNA sequencing using the fluorescent dideoxy terminator method. Results were compared with published sequence data and 24 control DNAs. Our results revealed several previously unreported common sequence polymorphisms, but overall frequencies were comparable between patients and controls. We conclude that mutation of neurturin is not a frequent cause of ISTC or IMC.
Acid challenge delays gastric pressure adaptation, blocks gastric emptying and stimulates gastric fluid secretion in the rat
Authors: Holzer P. , Painsipp E. , Jocic M. , Heinemann A. 
Published: March 2003

Abstract Functional dyspepsia can be associated with impaired gastric relaxation in response to food intake and delayed gastric emptying. In this study, we investigated whether luminal hydrochloric acid (HCl) may reproduce these motor alterations in phenobarbital‐anaesthetized rats via activation of extrinsic neural pathways. Intragastric pressure (IGP) changes induced by a 2‐mL fluid bolus were recorded with an oesophageal catheter, and gastric emptying was determined via the fluid volume recovered from the stomach 30‐min post‐bolus. Experiments involving acute nerve transections or pharmacological blockade of nitric oxide synthesis revealed that the initial increase of IGP after a 0.35 mol L−1 HCl bolus is dampened by duodenogastric and gastrogastric relaxation reflexes depending on vagal and splanchnic pathways as well as nitric oxide. Compared with saline, HCl (0.15–0.5 mol L−1) delayed the subsequent decrease (adaptation) of IGP, inhibited gastric emptying and stimulated gastric fluid secretion as seen in stomachs with ligated pylorus. The acid‐evoked delay in IGP adaptation and inhibition of gastric emptying involved duodenogastric and duodenopyloric extrinsic nerve reflexes, whereas the gastric fluid secretion was independent of the extrinsic innervation. It is proposed that the gastropyloric motor changes induced by luminal acid challenge have a bearing on the motor disturbances underlying functional dyspepsia.
Effect of sucking characteristics on breast milk creamatocrit
Authors: Aksit Sadik , Ozkayin Nese , Caglayan Suat 
Published: March 2003

SummaryOne of the problems in the care of healthy children is that mothers often give infant formulae to their normally growing infants in the first 4 months of life because they believe that they are unable to satisfy them. However, the association of fat content in breast milk with the sucking pattern of the infant is not clearly known. In order to determine whether the fat concentration of human milk was associated with sucking characteristics of the infants, 80 healthy 2‐month‐old babies and their mothers were included in the study. Milk creamatocrit was assessed at the beginning, at the first, fifth and 10th minutes and at the end of breast feeding. The creamatocrit values increased as the time elapsed from the beginning of breast feeding. There was an inverse relationship between milk volume and creamatocrit at both the beginning and the end of breast feeding (P < 0.05). The mean milk volume was higher and the mean creamatocrit at the end of breast feeding was lower in the infants whose 2‐month weight gain was higher than the 75th percentile (75P) compared with those whose 2‐month weight gain was lower than the 25th percentile (25P) (for milk volume 105 ± 36 mL vs. 76 ± 30 mL, respectively, P < 0.05; and for creamatocrit value 11.4 ± 4.0 vs. 14.3 ± 3.8, respectively, P < 0.05). Milk volume is the most important factor affecting weight gain of exclusively breast‐fed babies, and fat concentration of human milk is not a primary determining factor in individual differences in weight gain of the infants and appears to be secondary to factors such as number of feeds per day, duration of breast feeding and the volume of milk sucked.
Indices of birthweight‐specific perinatal mortality in Germany from 1985 to 1999
Authors: Rettwitz‐Volk Werner 
Published: March 2003

SummaryA study of the trends in German perinatal data over the 15 years from 1985 to 1999 is complicated by the fact that the numbers from 1991 onwards represent the data for reunified Germany, whereas the numbers before 1991 give the data for former West Germany. The latest figure for the number of livebirths in Germany was 770 744 in 1999 with a rate of low birthweight of 6.5% and a perinatal mortality rate of 0.62%. A constant increase in numbers of low‐birthweight infants was observed, rising from 33 531 in 1985 to 41 145 in 1990 and from 47 863 in 1991 to 50 294 in 1999. This rise in low‐weight births concerned mainly infants of <1500 g. In parallel, there was a decrease in early neonatal and infant mortality rates in all subgroups of low‐birthweight infants except for the extremely small infants of <500 g where no clear tendency was observed over 15 years.
A heart‐specific CD4+ T‐cell line obtained from a chronic chagasic mouse induces carditis in heart‐immunized mice and rejection of normal heart transplants in the absence of Trypanosoma cruzi
Authors: Ribeiro‐Dos‐Santos R. , Mengel J.O. , Postol E. , Soares R.A.O. , Ferreira‐Fernandez E. , Soares M.B.P. , Pontes‐De‐Carvalho L.C. 
Published: March 2003

To study the role of autoreactive T cells in the pathogenesis of cardiomyopathy in Chagas' disease, we generated a cell line by repeated in vitro antigenic stimulation of purified splenic CD4+ T lymphocytes from a chronically Trypanosoma cruzi‐infected mouse. Cells from this line were confirmed to be CD4+ CD8− and proliferated upon stimulation with soluble heart antigens from different animal species, as well as with T. cruzi antigen, in the presence of syngeneic feeder cells. In vitro antigen stimulation of the cell line produced a Th1 cytokine profile, with high levels of IFNγ and IL‐2 and absence of IL‐4, IL‐5 and IL‐10. The cell line also terminated the beating of fetal heart clusters in vitro when cocultured with irradiated syngeneic normal spleen cells. In situ injection of the cell line into well established heart transplants also induced the cessation of heart beating. Finally, adoptive transfer of the cell line to heart‐immunized or T. cruzi‐infected BALB/c nude mice caused intense heart inflammation.
A comparison of local and peripheral parasite‐specific antibody production in different strains of mice infected with Trichuris muris
Authors: Blackwell Nathan M. , Else Kathryn J. 
Published: March 2003

SummaryThe serum parasite‐specific antibody responses of different mouse strains infected with Trichuris muris reflect the nature of the T‐helper response mounted by the host, in that resistant Th2‐responding strains, such as BALB/K, produce immunoglobulin (Ig)G1 and susceptible predominantly Th1‐responding strains, such as AKR, produce IgG2a and IgG1. However, the kinetics of antibody production in the sera, as determined by enzyme‐linked immunosorbent assay, do not reflect infection status in that resistant strains can expel their worm burdens before antibodies are detectable in the sera. Here, we show that parasite‐specific antibody production by in vitro lipopolysaccharide‐stimulated mesenteric lymph node cells (MLN) not only correlate with serum antibody isotypes, but also follow expulsion kinetics. Additionally, the antibody levels seen locally match changes in absolute B220+ cell numbers in the MLN (determined by flow cytometry) and changes in MLN parasite‐specific plasma cells in the MLN (determined by ELISPOT). These results show that B cell responses are tightly regulated locally in both resistant and susceptible strains of mice infected with T. muris.
Toxoplasma gondii infection can regulate the expression of tumour necorsis factor‐α receptors on human cell in vitro
Authors: Derouich‐Guergour Dorra , Aldebert Delphine , Vigan Ines , Jouvin‐Marche Evelyne , Marche Patrice N. , Aubert Dominique , Ambroise‐Thomas Pierre , Pelloux Hervé 
Published: March 2003

SummaryThe in vitro regulation of tumour necrosis factor (TNF)‐α receptors during Toxoplasma gondii infection of human MRC5 fibroblasts and human myelomonocytic THP‐1 cells was investigated. Cells were infected with the virulent RH of T. gondii. TNFR membrane receptors were analysed by flow cytometry with biotinylated TNF‐α. Shedding of the soluble form of TNFR1 and TNFR2 in cell culture supernatants was measured by enzyme‐linked immunosorbent assay, and expression of mRNA production of TNFR1 and TNFR2 was analysed by quantitative real‐time ploymerase chain reaction, 1 h after infection. In the MRC5 cell line, T. gondii infection did not induce any up‐ or down‐regulation of membrane TNFRs, soluble TNFRs or mRNA of TNFRs. However, THP‐1 cell infection with living parasites induced a significant soluble TNFR1 release by THP‐1 cells after 1 h. We detected an approximately 50% up‐regulation (P < 0·01) of soluble TNFR1 in infected THP‐1 cells compared to controls. No change in soluble TNFR2 levels was observed in the same conditions. Moreover, infection decreased the level of TNF membrane receptors, but had no effect on TNFR1 and TNFR2 mRNA levels. TNFR modulation by T. gondii infection, in vitro, depends on the cell type. Furthermore, our data suggest that living parasites control the shedding of the soluble form of TNFR1. This mechanism may influence the role of TNF‐α in toxoplasmosis.
Attempts to immunize sheep against the scab mite, Psoroptes ovis
Authors: Smith W. D. , Bates P. , Pettit D. M. , Van Den Broek A. , Taylor M. A. 
Published: March 2003

SummaryAdult Psoroptes ovis were successively extracted in saline, 1% Tween, 1% Triton and 8 m urea +0·1% CHAPS. The Triton extract was separated into fractions which did or did not bind to ConA lectin. Using QuilA as adjuvant, both Triton fractions and the saline, Tween and urea extracts were tested separately as candidate protective antigens against a P. ovis challenge infestation in sheep. All induced circulating antibody responses, but the saline and Tween extracts also stimulated significant protective effects in those sheep which developed active disease. Compared to control sheep injected with adjuvant only, these immunized animals had more than two and seven‐fold reductions in mean lesion areas and mite numbers, respectively.
Mate finding in the forest cockchafer, Melolontha hippocastani, mediated by volatiles from plants and females
Authors: Ruther J. , Reinecke A. , Thiemann K. , Tolasch T. , Francke W. , Hilker M. 
Published: March 2003

SummaryThe response of the forest cockchafer, Melolontha hippocastani F. (Coleoptera, Scarabaeidae), towards volatiles emitted by different host plants and conspecifics was tested in field experiments during the flight period at dusk. Funnel traps containing artificially damaged leaves from the host plants Carpinus betulus L. and Quercus rubra L., as well as from the non‐host plant Prunus serotina Ehrh. caught significantly more beetles than empty control traps. On the other hand, traps baited with undamaged leaves from Q. rubra did not catch significantly more beetles than empty controls. Leaves from C. betulus damaged by beetle feeding did not attract more beetles than artificially damaged leaves. By use of gas chromatography coupled with electroantennographic detection (GC‐EAD) electrophysiological responses of males and females were shown for 18 typical plant volatiles. A synthetic mixture of selected typical green plant volatiles was also highly attractive in the field. A total of 9982 beetles was caught during the field experiments, among them only 33 females. This suggests that attraction to damaged foliage during flight period at dusk is male‐specific. Field experiments testing the attractiveness of female M. hippocastani towards conspecific males by employing caged beetles and beetle extracts indicated that males of M. hippocastani use a female‐derived sex pheromone for mate location. On wired cages containing either unmated feeding females, or unmated females without access to foliage, or feeding males in combination with extracts from unmated females, significantly more males landed during the flight period than on comparable control cages containing feeding males or male extracts. A possible scenario of mate location in M. hippocastani involving feeding‐induced plant volatiles and a female‐derived sex pheromone is discussed.
Topical application of Pya‐AKH stimulates lipid mobilization and locomotion in the flightless bug, Pyrrhocoris apterus (L.) (Heteroptera)
Authors: Kodrík Dalibor , Socha Radomír , Zemek Rostislav 
Published: March 2003

Abstract Two different methods of applying Pya‐AKH to long‐winged (macropterous) females of the firebug, Pyrrhocoris apterus (Linnaeus) (Heteroptera) were compared: both injection and topical application increased the levels of lipids in the haemolymph and stimulated locomotor activity. Lipid mobilization was maximal when 10 pmol was applied by injection or 40–100 pmol by topical application, with the first significant responses occurring 1.5 h after injection and 2 h after topical application. The highest elevations of lipid concentration in the haemolymph were comparable between the treatments, i.e. 14.36 ± 3.59 mg/mL for injection and 14.43 ± 4.07 mg/mL for topical application. However, these maximal elevations were achieved at different times: 3 h after the injection and 7 h after the topical application.Injection of 10 and 40 pmol of Pya‐AKH stimulated locomotor activity with maximal activity 3 h later but, surprisingly, injection of 80 pmol showed no effect initially and than a slight inhibitory effect after 6–8 h.Increased locomotor activity was found after topical application of Pya‐AKH, but the response was lower than after injection and appeared later, 5–9 h after the hormone application. In addition, the greatest increase in walking activity required topical application of 300 pmol and was still less dramatic than the response to injection. The stimulatory effect of Pya‐AKH on locomotion was positively correlated with its effect on lipid mobilization only for injection of the hormone. It is argued that a stress caused by injection could play a role in the appearance of the complex response to adipokinetic hormone.
Partitioning of reserve and newly assimilated carbon in roots and leaf tissues of Lolium perenne during regrowth after defoliation: assessment by 13C steady‐state labelling and carbohydrate analysis
Authors: Morvan‐Bertrand A. , Pavis N. , Boucaud J. , Prud’Homme M.‐P. 
Published: March 2003

ABSTRACTThe relative significance of the use of stored or currently absorbed C for the growth of leaves or roots of Lolium perenne L. after defoliation was assessed by steady‐state labelling of atmospheric CO2. Leaf growth for the first two days after defoliation was to a large extent dependent on the use of C reserves. The basal part of the elongating leaves was mainly new tissue and 91% of the C in this part of the leaf was derived from reserves assimilated prior to defoliation. However, half of the sucrose in the growth zone was produced from photosynthesis by the emerged leaves. Fructans that were initially present in elongating leaf bases were hydrolysed (loss of 93 to 100%) and the resulting fructose was found in the new leaf bases, suggesting that this pool may be used to support cell division and elongation. Despite a negative C balance at the whole‐plant level, fructans were synthesized from sucrose that was translocated to the new leaf bases. After a regrowth period of 28 d, 45% of the C fixed before defoliation was still present in the root and leaf tissue and only 1% was incorporated in entirely new tissue.