bluuebunny/crossref_metadata_2025 huggingface dataset:
The pivotal role of guanine phosphoribosyltransferase in purine salvage by Giardia lamblia
Authors: Munagala Narsimha , Wang Ching C.
Published: March 2003

Giardia lamblia is an anaerobic binucleate flagellated protozoan known to
lack de novo synthesis of purine nucleotides. Our previous metabolic studies
indicated two major parallel pathways mediated by adenine phosphoribosyltransferase
(APRT) and guanine phosphoribosyltransferase (GPRT) that constitute the primary route
of purine salvage in this organism. To verify further that these enzymes play a pivotal
role in replenishing the purine ribonucleotide pool and are required for replicative
growth of Giardia, a knock‐out of GPRT gene expression in this organism
was attempted. A hammerhead ribozyme flanked by two arms of GPRT antisense RNA (GPRZ)
was designed, synthesized and found capable of cleaving a GPRT mRNA fragment in
vitro at the designated site. GPRZ cDNA was then cloned into a viral vector pC631pac,
derived from the genome of giardiavirus (GLV), and its transcript was introduced
into GLV‐infected Giardia trophozoites by electroporation. Stable transformants
selected under increasing concentrations of puromycin displayed parallel increases
in ribozyme levels and associated decreases in GPRT mRNA levels, GPRT enzyme activity
and replicative cell growth to less than 10–20% of wild‐type levels.
Metabolite analyses showed specific depletion of the guanine ribonucleotide pools
in parallel with slower cell growth. We conclude that GPRT plays an essential role
in supplying guanine nucleotides required for growth and multiplication of Giardia, emphasizing its potential as a bona fide target for antigiardiasis chemotherapy.
The cell differentiation protein SpoIIE contains a regulatory site that controls its phosphatase activity in response to asymmetric septation
Authors: Feucht Andrea , Abbotts Laura , Errington Jeffery
Published: March 2003

Summary Starvation induces Bacillus subtilis to initiate a ­simple, two‐cell developmental process that begins with an asymmetric cell division. Activation of the first compartment‐specific transcription factor, σF, is coupled to this morphological event. SpoIIE, a bifunctional protein, is essential for the compartment‐specific activation of σF and also has a morphogenic activity required for asymmetric cell division. SpoIIE consists of three domains: a hydrophobic N‐terminal domain, which targets the protein to the membrane; a central domain, involved in oligomerization of SpoIIE and interaction with the cell division protein FtsZ; and a C‐terminal domain comprising a PP2C protein phosphatase. Here, we report the isolation of mutations at the very beginning of the central domain of spoIIE, which are capable of activating σF inde­pendently of septum formation. Purified mutant proteins showed the same phosphatase activity as the wild‐type protein in vitro. The mutant proteins were fully functional in respect of their localization to sites of asymmetric septation and support of asymmetric division. The data provide strong evidence that the phosphatase domain of SpoIIE is tightly regulated in a way that makes it respond to the formation of the asymmetric septum.
Nitric oxide scavenging and detoxification by the Mycobacterium tuberculosis haemoglobin, HbN in Escherichia coli
Authors: Pathania Ranjana , Navani Naveen K. , Gardner Anne M. , Gardner Paul R. , Dikshit Kanak L.
Published: March 2003

Nitric oxide (NO), generated in large amounts within the macrophages, controls and restricts the growth of internalized human pathogen, Mycobacterium tuberculosis H37Rv. The molecular mechanism by which tubercle bacilli survive within macrophages is currently of intense interest. In this work, we have demonstrated that dimeric haemoglobin, HbN, from M. tuberculosis exhibits distinct nitric oxide dioxygenase (NOD) activity and protects growth and cellular respiration of heterologous hosts, Escherichia coli and Mycobacterium smegmatis, from the toxic effect of exogenous NO and the NO‐releasing compounds. A flavohaemoglobin (HMP)‐deficient mutant of E. coli, unable to metabolize NO, acquired an oxygen‐dependent NO consumption activity in the presence of HbN. On the basis of cellular haem content, the specific NOD activity of HbN was nearly 35‐fold higher than the single‐domain Vitreoscilla haemoglobin (VHb) but was sevenfold lower than the two‐domain flavohaemoglobin. HbN‐dependent NO consumption was sustained with repeated addition of NO, demonstrating that HbN is catalytically reduced within E. coli. Aerobic growth and respiration of a flavohaemoglobin (HMP) mutant of E. coli was inhibited in the presence of exogenous NO but remained insensitive to NO inhibition when these cells produced HbN, VHb or flavohaemoglobin. M. smegmatis, carrying a native HbN very similar to M. tuberculosis HbN, exhibited a 7.5‐fold increase in NO uptake when exposed to gaseous NO, suggesting NO‐induced NOD activity in these cells. In addition, expression of plasmid‐encoded HbN of M. tuberculosis in M. smegmatis resulted in 100‐fold higher NO consumption activity than the isogenic control cells. These results provide strong experimental evidence in support of NO scavenging and detoxification function for the M. tuberculosis HbN. The catalytic NO scavenging by HbN may be highly advantageous for the survival of tubercle bacilli during infection and pathogenesis.
The tetracycline resistance protein Tet(○) perturbs the conformation of the ribosomal decoding centre
Authors: Connell Sean R. , Trieber Catharine A. , Stelzl Ulrich , Einfeldt Edda , Taylor Diane E. , Nierhaus Knud H.
Published: March 2003

Tet(○) is an elongation factor‐like protein found in clinical isolates of Campylobacter jejuni that confers resistance to the protein‐synthesis inhibitor tetracycline. Tet(○) interacts with the 70S ribosome and promotes the release of bound tetracycline, however, as shown here, it does not form the same functional interaction with the 30S subunit. Chemical probing demonstrates that Tet(○) changes the reactivity of the 16S rRNA to dimethyl sulphate (DMS). These changes cluster within the decoding site, where C1214 is protected and A1408 is enhanced to DMS reactivity. C1214 is close to, but does not overlap, the primary tetracycline‐binding site, whereas A1408 is in a region distinct from the Tet(○) binding site visualized by cryo‐EM, indicating that Tet(○) induces long‐range rearrangements that may mediate tetracycline resistance. Tetracycline enhances C1054 to DMS modification but this enhancement is inhibited in the presence of Tet(○) unlike the tetracycline‐dependent protection of A892 which is unaffected by Tet(○). C1054 is part of the primary binding site of tetracycline and A892 is part of the secondary binding site. Therefore, the results for the first time demonstrate that the primary tetracycline binding site is correlated with tetracycline's inhibitory effect on protein synthesis.
MglA, a small GTPase, interacts with a tyrosine kinase to control type IV pili‐mediated motility and development of Myxococcus xanthus
Authors: Thomasson Bobbie , Link Jason , Stassinopoulos Angela G. , Burke Neal , Plamann Lynda , Hartzell Patricia L.
Published: March 2003

The mglA gene encodes a 22 kDa GTPase that is critical for single‐cell (A) gliding, type IV pili‐mediated (S) gliding and development of Myxococcus xanthus. To identify components that interact with MglA to control these processes, second‐site mutations that restore movement to non‐motile mglA mutants were sought. An allele‐specific extragenic suppressor of mglA8, named mas815 (mglA8 suppressor 15), was obtained. mas815 does not bypass the requirement for MglA, yet it restores type IV pili‐mediated motility and starvation‐induced development. Single‐cell (A) motility is not restored. The suppressing mutation maps to the 3′ end of a gene, masK, in an operon immediately upstream of the mglBA operon. masK encodes a protein of the STY kinase family. When the masK gene was used as bait against a library carrying M. xanthus DNA in the yeast two‐hybrid system, eight positive, independent clones containing fusions of mglA to GAL4 were obtained, thus confirming the interaction between MglA and MasK. MasK, expressed in Escherichia coli, was shown to phosphorylate at a tyrosine residue(s). The gain‐of‐function in the masK815 mutant was correlated with increased production of extracellular fibrils, which are required for adhesion, cell–cell contact and sensing phosphatidylethanolamine chemoattractants. These data suggest that the interaction between MasK and MglA is an essential part of a signal transduction pathway controlling motility and development.
VirD4‐independent transformation by CloDF13 evidences an unknown factor required for the genetic colonization of plants via Agrobacterium
Authors: Escudero Jesús , Den Dulk‐Ras Amke , Regensburg‐Tuïnk Tonny J. G. , Hooykaas Paul J. J.
Published: March 2003

Agrobacterium
uses a mechanism similar to conjugation for
trans
‐kingdom transfer of its oncogenic T‐DNA. A defined VirB/VirD4 Type IV secretion system is responsible for such a genetic transfer. In addition, certain virulence proteins as VirE2 can be mobilized into host cells by the same apparatus. VirE2 is essential to achieve plant but not yeast transformation. We found that the limited host range plasmid CloDF13 can be recruited by the virulence apparatus of
Agrobacterium
for transfer to eukaryotic hosts. As expected the VirB transport complex was required for such
trans
‐kingdom DNA transfer. However, unexpectedly, the coupling factor VirD4 turned out to be necessary for transfer to plants but not for transport into yeast. The CloDF13 encoded coupling factor (Mob) was essential for transfer to both plants and yeast though. This is interpreted by the different specificities of Mob and VirD4. Hence, Mob being required for the transport of the CloDF13 transferred DNA (to both plants and yeast) and VirD4 being required for transport of virulence proteins such as VirE2. Nevertheless, the presence of the VirE2 protein in the host plant was not sufficient to restore the deficiency for VirD4 in the transforming bacteria. We propose that Mob functions encoded by the plasmid CloDF13 are sufficient for DNA mobilization to eukaryotic cells but that the VirD4‐mediated pathway is essential to achieve DNA nuclear establishment specifically in plants. This suggests that other
Agrobacterium virulence proteins besides VirE2 are translocated and essential for plant transformation.
Identification and characterization of genomic loci unique to the Brazilian purpuric fever clonal group of H. influenzae biogroup aegyptius: functionality explored using meningococcal homology
Authors: Li Ming‐Shi , Farrant Jayne L. , Langford Paul R. , Kroll J. Simon
Published: March 2003

Brazilian purpuric fever (BPF) is a fulminant septicaemic infection of young children, caused by a clonal group of strains of Haemophilus influenzae biogroup aegyptius (Hae), an organism previously solely associated with conjunctivitis. Their special capacity to invade from the initial site of conjunctival infection is unexplained. A polymerase chain reaction (PCR)‐amplified subtractive hybridization technique was used to identify genes specific to the BPF clonal group. A copy of bacteriophage HP1 and 46 further chromosomal loci were identified in the BPF but not in the conjunctivitis strain of Hae. Sixteen were characterized further, and one – encoding an analogue of the Legionella pneumophila epithelial cell entry‐enhancing protein EnhC – was investigated in depth. Two genes, bpf001 and bpf002, unique to the BPF clonal group were identified between homologues of HI1276 and HI1277 in a complex locus close to H. influenzae genetic island 1, recently identified in pathogenic H. influenzae type b. Bpf001 encodes a protein homologous to EnhC and to the previously uncharacterized product of the meningococcal gene NMB0419. Functional studies of bpf001 proving intractable, NMB0419 was chosen as a surrogate for investigation and shown to modulate bacterial interaction with monolayers of human respiratory epithelial cells, promoting invasion, the first stage (for Hae) in the pathogenesis of BPF.
A comparison of micromanometric and standard manometric techniques for recording of oesophageal motility
Authors: Chen W.H. , Omari T.I. , Holloway R.H. , Checklin H. , Dent J.
Published: March 2003

Perfused micromanometric assemblies with an outer diameter of 2 mm or less have been developed for use in premature infants and small laboratory animals. Such assemblies offer advantages with regard to subject comfort and low perfusion rates that make them attractive for use in adults. The aim of this study was to investigate the recording fidelity of micromanometric assemblies in the measurement of oesophageal peristalsis in adults. Two micromanometric assemblies with an outer diameter of 1.8–2.0 mm and a length suitable for use in adults (165 cm), and containing micromanometric lumina of 0.28–0.35 mm i.d. and a standard lumen of 0.6–0.75 mm i.d. were evaluated. Each assembly was tested by measurement of pressure rise rate in response to sudden occlusion, and in vivo during oesophageal peristalsis by simultaneous comparison with an intraluminal strain gauge. At perfusion rates of 0.01–0.15 mL min−1 microlumina achieved pressure rise rates of 21–430 mmHg sec−1 that were comparable to 37–390 mmHg sec−1 for the standard lumina perfused at 0.15–0.6 mL min−1. During oesophageal peristalsis, micromanometric lumina recorded the occurrence and timing of all pressure waves accurately when compared with standard lumina and the microtransducer. However, microlumina under‐recorded pressure wave amplitude to varying degrees dependent upon perfusion rate although the performance of microlumina could be improved to that of the standard lumen by shortening their length to 70 cm. Micromanometric assemblies are suitable for recording oesophageal peristalsis in adults although there is some impairment of absolute manometric fidelity. Fidelity can be improved by minimizing total assembly length.
Initiation of phase III contractions in the jejunum by atropine, hexamethonium and xylocaine in conscious dogs
Authors: Tohara  , Uchida  , Suzuki  , Itoh
Published: March 2003

Mechanisms of initiation of phase III contractions in the jejunum during the digestive state are not well understood. To test whether phase III can be induced by a local injection of various agents in a jejunal segment, a polyethylene tube was chronically placed in a branch of the jejunal artery, and force transducers were chronically placed in the upper jejunum. Local injection of atropine, hexamethonium and xylocaine induced caudal‐migrating phase III in the injected segment only in the digestive state, and simultaneous intra‐arterial infusions of L‐arginine, an NK‐1 antagonist, or 5‐hydroxytryptamine (5‐HT) 1P and 3 antagonists inhibited the induced phase III. Intravenous atropine and hexamethonium also inhibited xylocaine‐induced phase III contractions. Atropine and hexamethonium‐induced phase III were brought about by inhibition of neural transmission at nicotinic receptors in the inhibitory pathway to NO neurones. NK‐1, 5‐HT1P and 5‐HT3 receptors are present in the excitatory but not the inhibitory pathway to NO neurones. Xylocaine appears to stop neuronal transmission from mechanoreceptors to NO neurones. Thus, the initiation of spontaneous occurrence of phase III in the digestive jejunum is likely to be brought about by transient cessation of postprandial contractions in a segment of the jejunum.
Influence of a 5HT1 receptor agonist on gastric accommodation and initial transpyloric flow in healthy subjects
Authors: Vingerhagen  , Hausken  , Gilja  , Berstad
Published: March 2003

Sumatriptan, a 5HT1 receptor agonist, inhibits antral motor activity, delays gastric emptying and relaxes the gastric fundus. The aim of this study was to characterize the effect of sumatriptan on transpyloric flow and gastric accommodation during and immediately after ingestion of a liquid meal using duplex sonography. Ten healthy subjects were investigated twice on separate days. In random order either sumatriptan 6 mg (Imigran® 0.5 mL) or a placebo were given s.c. 15 min before ingesting 500 mL of a meat soup. The subjects were examined during the 3‐min period before ingestion of the liquid meal, the 3‐min spent drinking the meal and 10 min postprandially. Sumatriptan caused a significant widening of both the gastric antrum (P=0.02) and the proximal stomach (P=0.01) 10 min postprandially as compared with placebo. It caused no significant differences in time to initial gastric emptying (P=0.2), but significantly delayed commencement of peristaltic‐related transpyloric flow (P=0.04). Sumatriptan had no significant effect on mean abdominal symptom scores, but after sumatriptan there was a significant negative correlation between width of postprandial antral area and postprandial nausea and between width of postprandial antral area and postprandial bloating. We therefore conclude that sumatriptan causes a postprandial dilatation of both the distal and the proximal stomach with no change in dyspeptic symptoms nor in length of time to first gastric emptying. Time to commencement of peristaltic‐related emptying is delayed.
Experimental hypertrophy of myenteric neurones in the pig: a morphometric study
Authors: Brehmer  , Göbel  , Frieser  , Graf  , Radespiel‐Tröger  , Neuhuber
Published: March 2003

Muscular hypertrophy in the ileum of two pigs aged 6 weeks was induced using two different surgical techniques, narrowing of the gut circumference (mechanical stenosis) and segmental reversal of an ileal loop which results in a persistent antiperistalsis of that segment (functional stenosis). These pigs were sacrificed 5–6 weeks postoperatively. Cross sections through the gut wall at various distances from the operation sites revealed marked muscular hypertrophy in the pre‐stenotic regions and in the reversed segment. Whole mounts from pre‐ and post‐stenotic, as well as reversed ileal regions, were silver‐ impregnated. The corresponding ileal region of a third, nonoperated pig served as control. Using a computer‐aided morphometric device, somal areas of five morphological neurone types were measured at various distances orally and anally from the operation sites and along the control ileum. Values between hypertrophic and nonhypertrophic zones as well as between two corresponding zones of nonoperated ileum were compared statistically. Along the control ileum, values revealed no differences in soma sizes. Within the experimentally altered material, somal areas of type VI neurones showed marked hypertrophy related to the sites of muscular hypertrophy whereas the other types remained constant throughout (II, IV in segmental reversal) or showed slightly larger somal areas within the post‐stenotic, nonhypertrophied zones (I, V, IV in stenosis). Additionally, within the reversed segment, neuronal perikarya of type I, II, IV and V neurones were larger as compared to the neighbouring regions. However, this enlargement of perikarya within the reversed segment may not be correlated with muscular hypertrophy but rather with the transections of intramural axons before reversing this segment. The results suggest that morphologically distinct neurone types may play different roles within the mechanically stressed small intestine and possibly also in the coordination of normal muscular function.
Effect of alpha‐2 adrenoceptor antagonists on colonic function in rats
Authors: Yamamoto O. , Niida H. , Tajima K. , Tanaka M. , Makita Y. , Ueda F. , Yano J.
Published: March 2003

We studied the effect of alpha‐2 adrenoceptor antagonists on colonic function stimulated by water‐avoidance stress, 5‐hydroxytryptamine (5‐HT), bethanechol and castor oil by comparison with the effects of atropine and a 5‐hydroxytryptamine 3 (5‐HT3) receptor antagonist, ondansetron. Yohimbine, idazoxan and atropine, but not ondansetron, significantly inhibited water‐avoidance stress‐stimulated faecal excretion. Yohimbine and idazoxan inhibited neither 5‐HT‐ nor bethanechol‐stimulated faecal excretion. In contrast, atropine inhibited both 5‐HT‐ and bethanechol‐stimulated faecal excretion and ondansetron inhibited 5‐HT‐stimulated faecal excretion. Yohimbine did not inhibit the incidence of diarrhoea induced by castor oil, but idazoxan significantly inhibited diarrhoea observed during a 1‐h period after the administration of castor oil. Both atropine and ondansetron inhibited diarrhoea during a 2‐h period after the administration of castor oil. These findings suggest that alpha‐2 adrenoceptor antagonists specifically inhibit colonic motor function stimulated by stress in rats.
Nitrergic and cholinergic vagal pathways involved in the regulation of canine proximal gastric tone: an in vivo study
Authors: Paterson  , Anvari  , Tougas  , Huizinga
Published: March 2003

To better understand the relationship between cholinergic and nitrergic (NO) innervation in the regulation of proximal gastric (fundic) tone in vivo, the effects of nitric oxide synthase blockade on fundic tone were studied in conscious dogs using vagal cooling and an electronic barostat. Vagal cooling, atropine (0.05 mg kg−1 i.v. bolus) and hexamethonium (1 mg kg−1 i.v. bolus) all markedly decreased fundic tone as reflected by increased intragastric volume, indicating a significant contribution of vagal and enteric cholinergic pathways to the maintenance of canine fundic tone. Administration of
L‐NNA (10 mg kg−1 i.v. bolus) increased fundic tone and the effects of
L‐NNA were completely prevented by prior vagal cooling or atropine administration, but not by pretreatment with hexamethonium. The relaxation effects of neurally derived NO appear primarily related to inhibition of ongoing vagal cholinergic activity. The data are consistent with the primary site of action of nitrergic mechanisms on gastric fundic tone in conscious dogs being at a presynaptic site on vagal cholinergic efferent nerves.
Pharmacological and molecular characterization of muscular cholecystokinin receptors in the human lower oesophageal sphincter
Authors: González A. A. , Farré R. , Monés J. , Capellà G. , Clavé P.
Published: March 2003

In vitro cholecystokinin (CCK) contracts the human lower oesophageal sphincter by stimulating muscular receptors. The aim of this study was to characterize the muscular CCK receptor subtypes in the human lower oesophageal sphincter. Twenty‐five circular strips from six patients were studied. RNA was extracted, reverse transcribed, and cDNAs were amplified with primers for human CCK‐A and B receptors. The potency of the contraction induced by CCK‐8, desulphated CCK‐8, and gastrin‐I, and the effect of the CCK‐A (loxiglumide and SR 27897) and the CCK‐B (YM022 and L‐365 260) specific receptor antagonists were compared. Both CCK‐A and CCK‐B receptor mRNAs were found in functional lower oesophageal sphincter strips. The potency of the CCK‐8 concentration‐dependent contraction was two and three orders of magnitude higher than that of desulphated CCK‐8 and gastrin‐I, respectively. The CCK‐8‐induced contraction was blocked by the CCK‐A receptor antagonists loxiglumide (IC50 11 μmol L–1) and SR 27897 (IC50 74 nmol L–1) but not by CCK‐B receptor antagonists (1 μmol L–1).Our data suggest that, although the human lower oesophageal sphincter expresses both CCK‐A and CCK‐B receptors, the contractile effect of CCK‐8 on the circular muscle is mainly due to the activation of CCK‐A receptors.
Alterations of neurokinin receptors and interstitial cells of Cajal during and after jejunal inflammation induced by Nippostrongylus brasiliensis in the rat
Authors: FAUSSONE‐PELLEGRINI M‐S. , GAY J. , VANNUCCHI M‐G. , CORSANI L. , FIORAMONTI J.
Published: March 2003

Substance P (SP) and its receptors NK1 and NK2 are widely expressed in the intestinal wall by neurones, interstitial cells of Cajal (ICC) and smooth muscle cells. Changes in SP and/or its NK receptors have been documented during experimental inflammation in animals or inflammatory bowel diseases in humans, but the data concern the acute phase of the inflammatory process. We determined immunohistochemically whether NK receptors and SP were altered in the muscle coat during jejunal inflammation induced by the nematode Nippostrongylus brasiliensis and whether these alterations persisted when inflammation had spontaneously resolved 30 days postinfection. An ultrastructural analysis was also conducted on ICC, nerves and muscle. At day 14, when inflammation peaked, there was a reduction in NK1 receptors in myenteric neurones and in SP‐immunoreactive nerve endings. There were also ultrastructural anomalies in synaptic vesicles and NK2 receptor loss in the circular muscle layer. The SP decrease persisted at day 30, whereas neurones and circular muscle cells re‐expressed NK1 and NK2 receptors, respectively. The ICC at the deep muscular plexus, located near to the inflammatory site, underwent alterations leading to their complete loss at day 30. These morphological changes are probably associated with impairment in tachykinergic control of jejunal functions leading to the alterations of motility and sensitivity to distension already described in these animals.
Effects of ileal bile salts on fasting small intestinal and gallbladder motility
Authors: Van Ooteghem N. A. M. , Samsom M. , Van Erpecum K. J. , Van Berge‐Henegouwen G. P.
Published: March 2003

Abstract
 In the fasting state, gallbladder emptying is related to phase III of the intestinal migrating motor complex. The effects of ileal infusion of mixed taurocholate‐phospholipid micelles on fasting small intestinal motility (by a 17‐channel catheter with side holes located in duodenum, jejunum and ileum) and gallbladder motility (by ultrasound) were investigated in eight healthy volunteers. After bile salt depletion by cholestyramine, 0.9% NaCl or mixed micelles were infused in the ileum during phase II of the migrating motor complex. Time to onset of subsequent phase III was significantly shorter after infusion of mixed micelles compared with 0.9% NaCl (32 ± 5 min vs. 60 ± 5 min, P = 0.01). Distal to the infusion port, numbers of pressure waves and their amplitudes were significantly lower during bile salt infusion compared with 15 min before infusion (11 ± 6 per 15 min vs. 21 ± 8 per 15 min, and 2.4 ± 0.6 kPa vs. 2.8 ± 0.5 kPa, respectively). Micellar infusions increased fasting gallbladder volumes to 170 ± 5% of starting volumes (P < 0.0001). In conclusion, ileal infusion of mixed micelles influences the timing of phase III of the intestinal migrating motor complex, inhibits ileal motility and increases fasting gallbladder volumes. These findings may have important consequences for enterohepatic circulation of bile salts.
Ileal manometry in children following ileostomies and pull‐through operations
Authors: Sood M. R. , Cocjin J. , Di Lorenzo C. , Narasimha Reddy S. , Flores A. F. , Hyman P. E.
Published: March 2003

Abstract Our aim was to analyse the patterns of ileal contractions in children. We reviewed the charts of 23 children who had ileal manometry studies (16 males), mean age 7 years (range 2 months to 17 years). We positioned the manometry catheters with 4–8 recording sites, 5 or 15 cm apart, through ileostomies fashioned for clinically indicated reasons. We studied six additional children with persistent faecal soiling following endorectal pull through for Hirschsprung's disease; the catheters were positioned through the anus and colon into the ileum. We recorded phasic and tonic intermittent contractions in all the subjects, clustered contractions (rate 5–9 min−1, duration 20–120 s) in 19 subjects with ileostomies and four with endorectal pull throughs. In 13 children there were prolonged propagated contractions, > 60 mmHg in amplitude, > 15 s in duration, propagating at rates of 2–6 cm s−1 over at least 20 cm. The migrating motor complex was rare; in 55 h of fasting recording there were two phase III sequences. There are four distinctive features of ileal manometry recordings in children: random intermittent contractions, clustered contractions, prolonged propagated contractions and tonic contractions. The features of ileal motility differ from motility in the proximal small bowel.
Fully automated analysis of colonic manometry recordings
Authors: De Schryver A. M. P. , Samsom M. , Akkermans L. M. A. , Clemens C. H. M. , Smout A. J. P. M.
Published: March 2003

Abstract The purpose of this study was to develop a computer program for fully automated analysis of all presently known motor patterns in human colonic motility recordings. Colonic pressure recordings obtained from 24 healthy volunteers were used. Algorithms were developed for the detection and numerical analysis of five types of pressure waves: antegrade, retrograde, simultaneous, high‐amplitude and isolated pressure waves. Furthermore, periodical motor activity was quantified. Validation was performed by comparison with visual analysis by two experienced observers. Patterns recorded during day‐ and night‐time were compared using multiple‐factor analysis of variance with Bonferroni correction. Automated analysis correlated well with visual peak detection (r = 0.98, P <0.01) and detection of antegrade pressure waves (r = 0.98, P <0.01). Most motor patterns showed a diurnal variation. During the night, prevalences of antegrade (938 vs 455; P <0.05), retrograde (112 vs 81; P <0.05), high‐amplitude (12.9 vs 1.3; P <0.05), isolated pressure waves (1114 vs 765; P <0.05), and periodic motor activity were decreased (7.33 vs 4.47%; P <0.05). However, when expressed as percentage of absolute numbers of pressure waves, prevalences remained constant. In conclusion, fully automated analysis of all hitherto described colonic motility patterns is feasible. During the night, overall wave prevalences markedly decreased, but the distribution over the various motor patterns was preserved.
Isochromosome 17q is a constant finding in medulloblastoma. An interphase cytogenetic study on tissue sections
Authors: Giordana  , Migheli  , Pavanelli
Published: March 2003

Isochromosome 17q (i[17q]) is the most frequent chromosomal abnormality in medulloblastoma, occurring in 30–60% of cases by karyotype analysis. In the present study i[17q] was demonstrated in routinely processed tissue sections of 20 medulloblastomas by in situ hybridization (ISH), using a chromosome 17 centromeric alpha satellite DNA probe. All medulloblastomas showed the i[17q] specific signal, i.e. two hybridization spots slightly apart from each other. The specific hybridization signal was not observed in ependymomas, cerebellar astrocytomas, haemangioblastomas, supratentorial neuroblastomas and ependymoblastomas. The constant finding of i[17q] in medulloblastoma depends on the much higher number of nuclei which can be analysed by ISH compared with cytogenetic techniques. Molecular data on medulloblastoma are consistent with the present results. The number of cells with i[17q] in medulloblastoma cases ranged from 3% to 9%; these figures are underestimated because of nuclear truncation in tissue sections. The percentage was not linked to patients’ age, location of tumour, MIB‐1 labelling index and histological type (classical vs desmoplastic). The present results indicate that i[17q] is a key event in the pathogenesis of medulloblastoma, and suggest a genetic difference between medulloblastoma and other primitive neuroectodermal tumours
A comparison of manual and semi‐automated methods in the assessment of axonal injury
Authors: Gentleman  , McKenzie  , Royston  , McIntosh  , Graham
Published: March 2003

Diffuse axonal injury (DAI) in the central nervous system is a common cause of post‐traumatic coma and may result in varying degrees of disability up to and including the vegetative state. Experimental studies in man and animals have previously relied upon semiquantitative grading systems for determining the relationship between the extent of DAI and the clinical features of patients. Using β‐amyloid precursor protein immunocytochemistry for the detection of DAI in sections of corpus callosum from 15 cases of fatal head injury, we have developed a quantitative image analysis technique for the assessment of axonal injury. This new method is objective and reproducible and should allow better correlation with biomechanical, radiological, and clinical parameters to increase our understanding of DAI.
Smoking and blood pressure patterns in normotensive pregnant women
Authors: Matkin  , Britton  , Samuels  , Eskenazi
Published: March 2003

This paper examines the relationship between smoking levels and blood pressure patterns of normotensive pregnant women in a prospective cohort of 2193 primiparous and 3176 multiparous, normotensive, Caucasian women selected from the Child Health and Development Studies in Oakland, California, 1959–67. Regression lines were fitted to each woman’s blood pressure; mean intercept and slope estimates of the individual regressions were used to create summary profile lines for each smoking dose. Multivariable regression analysis controlled for maternal age, number of visits to the doctor after 20 weeks’ gestation, body mass index and maternal education level. Overall, smokers had lower average diastolic blood pressure (smokers vs. nonsmokers adjusted mean: primiparas, 66.1 vs. 67.2 mmHg; and multiparas, 64.0 vs. 64.7 mmHg) but higher systolic blood pressure (smokers vs. nonsmokers adjusted mean: primiparas, 117.0 vs. 116.0; and multiparas, 112.5 vs. 110.0) than nonsmokers among primiparous and multiparous pregnant women after adjusting for potential confounders. However, these differences are small and there was no clear dose–response relationship between smoking level and blood pressure.
Breech delivery at term in Denmark, 1982–92: a population‐based case–control study
Authors: Krebs  , Langhoff‐Roos
Published: March 2003

The aim of the study was to determine the influence of intended mode of delivery on neonatal outcome in term breech delivery and to identify risk factors at intended vaginal delivery. Based on register data on all deliveries of non‐malformed, singleton fetuses in breech presentation at term (n = 19 476) in Denmark, 1982–92, a review of medical records of all (n = 218) cases with Apgar score < 7 at 5 minutes, including intrapartum and early neonatal deaths and 412 controls, was performed. Planned vaginal delivery was associated with a 15 times greater risk of low Apgar score than elective Caesarean section. Low Apgar score was correlated with duration of second stage of labour, but not with age, parity, birthweight, induction, augmentation or duration of first stage of labour. In conclusion, a pre‐labour decision on vaginal delivery was associated with a 15‐fold increase in low Apgar score. Prediction of low Apgar score in women selected for vaginal delivery does not seem possible before the second stage of labour.
Epidemiology of holoprosencephaly in Hawaii, 1986–97
Authors: Forrester Mathias B. , Merz Ruth D.
Published: March 2003

Holoprosencephaly is a birth defect affecting the medial structures of the brain and face. This investigation examined the epidemiology of holoprosencephaly in Hawaii between 1986 and 1997, using data obtained from a birth defects registry, and compared the results with those of other population‐based studies. Twenty‐five cases were identified, producing a prevalence of 1.09 per 10 000 livebirths. There were 17 (68.0%) livebirths, two (8.0%) fetal deaths and six (24.0%) elective terminations. Ten (58.8%) of the livebirths died before the age of 1 year. Seven (28.0%) had a known chromosomal abnormality, most often trisomy 13. Prevalence rates were higher for maternal age > 39 years, maternal race/ethnicity of Far East Asian or Filipino, females and residence in Maui County. The small number of cases limited the statistical significance of the study. However, this report confirms many of the findings from the previous studies and adds new findings, particularly the higher prevalence among Far East Asians and Filipinos.
The relationship between inside and outside ambient temperatures in Christchurch, New Zealand
Authors: Schluter P.J. , Macey P.M. , Ford R.P.K.
Published: March 2003

The objective of this study was to examine and identify relationships between hourly recorded meteorological temperature and ambient temperature, measured from within the home‐sleeping environment of young infants’ homes in Christchurch, New Zealand. From 1991 to 1994, home polysomnography recordings were conducted for up to 6Ê weeks on 32 infants aged between 2 and 24Ê weeks. One of the recorded signals was ambient room temperature. In total, 15 735 hourly recordings of this temperature were available for analysis. The New Zealand Meteorological Service supplied hourly recordings of climatic temperature, collected over this time, from an exposed site that was considered to be representative of weather conditions for Christchurch. Temperature seasonality, hourly climatic temperature recordings and the interaction of these variables were found to be significantly related to the indoor ambient temperature recordings (all had P < 0.001). Fluctuations in hourly recorded indoor temperature appeared to lag outdoor temperature fluctuations by approximately 2Ê h; hence, a strong autocorrelation was identified in the regression residuals. The most parsimonious autoregression model accounted for 97% of the variability in the hourly indoor temperature measurements (r2 = 0.97). In Christchurch houses, which typically have poor thermal insulation properties, yet have no central heating capabilities, a very strong association between indoor and outdoor temperatures was clearly demonstrated.
Risk factors for spontaneous preterm birth in two urban areas of Ukraine
Authors: Monaghan Susan C. , Little Ruth E. , Hulchiy Olesya , Strassner Howard , Gladen Beth C.
Published: March 2003

The economic, social and health problems faced by former eastern bloc countries after the demise of the Soviet Union are unique in the recent history of Europe. We conducted a study in two urban areas of Ukraine, asking if the traditional predictors of preterm delivery continue to be associated with risk under these conditions. Subjects were pregnant women with last menstrual period (LMP) between 25 December 1992 and 23 July 1994. Self‐completed questionnaires and the medical record provided data. We compared 137 spontaneous preterm deliveries with 2886 full‐term births, using all established risk factors for which we had data. Maternal age was the variable most strongly related to preterm birth. Being 18 or less had an odds ratio (OR) of 3.7; being 30+ had an OR of 2.5 relative to the reference group of age 25–29. Placental complications and pre‐existing hypertension had ORs of 2.7 and 2.3, respectively, but the confidence interval included 1.0. Low net pregnancy weight gain (less than 10 kg) was significantly associated with preterm birth, but the rate of net weight gain was not. Marital status and educational category were only weakly related. We conclude that although Ukraine faced serious difficulties during its transition to a market economy, these problems did not generally alter the outcome of pregnancy in our sample when the classic risk factors for preterm delivery were present.
Factors determining admission to neonatal units in Jamaica
Authors: Samms‐Vaughan Maureen E. , Ashley Deanna C. , McCaw‐Binns Affette M.
Published: March 2003

In order to identify the factors associated with admission to neonatal care units in a developing country, 1823 newborns admitted to Jamaica’s eight neonatal care units over a 6‐month period were compared with 9563 newborns identified during an island‐wide population morbidity study. Maternal sociodemographic characteristics, past obstetric history, infant’s growth parameters at birth and mode and place of delivery were investigated. Babies of mothers resident in the two regions of the island where specialist paediatric services were available had increased odds of admission (OR = 1.45, 1.22) compared with those living elsewhere (OR = 0.70, 0.80). Maternal history of a previous miscarriage, termination or early neonatal death were associated with subsequent admission, but a previous stillbirth or late neonatal death were not. Very low birthweight infants of gestational age 28–31 weeks were more likely to be admitted than those < 28 weeks with ORs of 1.45 and 0.34 respectively. Factors determining neonatal admission in the developing world may be quite different from those of developed countries. The development of guidelines and support services to ensure wider access to these services for those most in need could contribute to more equitable utilisation of services.
IgE responses in the serum and gastric lymph of sheep infected with Teladorsagia circumcincta
Authors: HUNTLEY  , SCHALLIG  , KOOYMAN  , MACKELLAR  , MILLERSHIP  , SMITH
Published: March 2003

The IgE response of naive or previously infected sheep to 50 000 infective larvae of Teladorsagia circumcincta was monitored in serum and gastric lymph using a monoclonal antibody generated to recombinant ovine IgE in a dot blot assay. In 4/5 naive sheep, lymph and serum IgE concentrations increased from days 8 and 14 after infection, respectively. In most previously infected sheep, the IgE response to challenge was more rapid, although not necessarily greater than that following a primary infection. IgE concentrations in lymph were some 4‐fold higher than in serum indicating that its source was the mucosa or draining nodes.
Definition of T cell epitopes within the 19 kDa carboxylterminal fragment of Plasmodium yoelii merozoite surface protein 1 (MSP119) and their role in immunity to malaria
Authors: TIAN JING‐HUI , GOOD MICHAEL F. , HIRUNPETCHARAT CHAKRIT , KUMAR SANJAI , LING IRENE T. , JACKSON DAVID , COOPER JUAN , LUKSZO JAN , COLIGAN JOHN , AHLERS JEFFERY , SAUL ALLAN , BERZOFSKY JAY A. , HOLDER ANTHONY A. , MILLER LOUIS H. , KASLOW DAVID C.
Published: March 2003

MSP119 is one of the leading malaria vaccine candidates. However, the mechanism of protection is not clear. To determine whether MSP119‐specific effector T cells can control parasitaemia, we analysed the specificity of T cells induced following immunization with recombinant forms of P. yoelii MSP119 and asked whether they could protect mice. There was no evidence that effector T cells were capable of protecting since: (1) immunization of mice with yMSP119, but not defined epitopes, was able to induce protection; and (2) long term MSP119‐specific CD4+ T cell lines were incapable of adoptively transferring protection. In contrast, priming mice with the T cell epitopes resulted in a rapid anamnestic antibody response to MSP119 after either challenge with MSP119 or parasite. Thus, MSP119 contains multiple T cell epitopes but such epitopes are the targets of helper T cells for antibody response but not of identified effector T cells capable of controlling parasitaemia.
Interferon‐γ signal transduction during parasite infection: modulation of MAP kinases in the infection of human monocyte cells (THP1) by Toxoplasma gondii
Authors: GOMEZ‐MARIN JORGE E. , VALERE AUDREY , BONHOMME ANNIE , EL'BTAOURI HASSAN , ANTONICELLI FRANK , BURLET HENRIETTE , AUBERT DOMINIQUE , VILLENA ISABELLE , GUENOUNOU MONCEF , HAYE BERNARD , PINON JEAN M.
Published: March 2003

We assayed mitogen‐activated protein (MAP) kinase phosphorylation in a human monocyte cell line (THP1) during their infection by Toxoplasma gondii. In addition, we tested the effect of specific MAP kinase inhibitors (PD098059 and SB203580) on parasite invasion. MAP kinase phosphorylation was increased in the cytosol and membrane fractions of THP1 infected with T. gondii. The MAP kinase phosphorylation of uninfected THP1 cells was not significantly modified by incubation for 20 h with 1000 U/ml of IFN‐γ. However, IFN‐γ treatment of infected cells significantly reduces the increase in phosphorylation caused by parasite infection. There was also MAP kinase activity in the cytosol and membrane fractions of extracellular T. gondii tachyzoites. IFN‐γ altered the distribution of activity in subcellular fractions of extracellular T. gondii tachyzoites. This indicates that IFN‐γ directly affects parasite MAP kinase activity. The results provide evidence that MAP kinase pathways participate in the infection by T. gondii and that the decrease in MAP kinase activity in infected cells caused by IFN‐γ may be involved in mediating their protective signals.
Definition and mapping of epitopes recognized by specific monoclonal antibodies to Schistosoma bovis 28 kDa glutathione S‐transferase: relation with anti‐egg viability immunity
Authors: DA COSTA ALEXANDRA VIANA , LAFITTE SOPHIA , FONTAINE JOSETTE , BOSSUS MARC , GRAS‐MASSE HÉLÈNE , CAPRON ANDRÉ , GRZYCH JEAN‐MARIE
Published: March 2003

Monoclonal antibodies to the 28kDa glutathione S‐transferase of Schistosoma bovis have been constructed in mice and used to characterize the epitope(s) potentially implied in the induction of anti‐fecundity and anti‐egg viability immune responses. Among the MoAbs produced three were particularly studied: Sb4‐50 (IgG2a) and Sb4‐56 (IgG1) which inhibited Sb28GST activity and Sb4‐10 (IgG1) which did not. The use of overlappting peptides covering the entire amino acid sequence of Sb28GST, allowed us to define the linear epitopes recognized by these anti‐Sb28GST MoAbs. Amino acid residues 202‐211 were recognized by both MoAbs Sb4‐50 and Sb4‐56 and MoAb Sb4‐10 recognized amino acid residues 58‐67. Their capacity to inhibit GST activity suggested binding to the active site or to neighbouring regions, which include the C‐terminal domain (a.a. 190‐211) of the protein. When passively transfered into BALB/c mice MoAbs induced a significant reduction in egg hatching and an increase in immature eggs. Effects on worm burdens were, however, variable and no clear‐cut association between the inhibition of enzyme activity and anti‐fecundity or anti‐viability activities was recorded. Our data indicate that beside the anti‐fecundity and anti‐viability immunity related to the impairment of GST activity, immune response to epitopes located in other regions of the molecule also contribute to the reduction of egg viability.
Innate resistance to experimental Trypanosoma congolense infection: differences in IL‐10 synthesis by macrophage cell lines from resistant and susceptible inbred mice
Authors: KAUSHIK RADHEY S. , UZONNA JUDE E. , RADZIOCH DANUTA , GORDON JOHN R. , TABEL HENRY
Published: March 2003

BALB/c and C57Bl/6 mice differ in resistance to T. congolense infections. We investigated the production of various cytokines (IL‐10, IL‐6, TNF‐α and TGF‐β) by macrophages from these mice. Macrophage cell lines (BALB.BM cells) of BALB/c mice but not (ANA‐1 cells)of C57BL/6 mice constitutively produced IL‐10. Challenge of these cells with trypanosomes induced the production of 50–100 times more IL‐10 in BALB.BM cells than in ANA‐1 cells. Pre‐incubation of the cell lines with IFN‐γ, prior to the trypanosome challenge, further upregulated this IL‐10 production in BALB.BM but not in ANA‐1 cells. Primary cultures of bone marrow‐derived macrophages (BMDM) from BALB/c mice also produced more IL‐10 following challenge with IFN‐γ and opsonized trypanosomes than did the C57Bl/6 BMDM. Similarly after challenge with trypanosomes, BALB.BM and BALB/c BMDM produced significantly more IL‐6 than did the analogous cells from the C57Bl/6 mice following such challenges. Higher steady state levels of TNF‐α mRNA accumulated in ANA‐1 cells than in BALB.BM cells following challenge with IFN‐γ and opsonized trypanosomes. Findings of this study for the first time indicate a differential regulation of cytokines (IL‐10, IL‐6 and TNF‐α) in macrophages of mice that significantly differ in their susceptibility to infections with T. congolense.