bluuebunny/crossref_metadata_2025 huggingface dataset:
Human postprandial gastric emptying of indigestible solids can occur unrelated to antral phase III
Authors: Stotzer  , Abrahamsson
Published: March 2003

According to animal experiments, postprandial gastric emptying of indigestible solids is mainly related to the antral phase III activity of the migrating motor complex. Gastric emptying of indigestible solids in humans has not been directly correlated to pressure recordings. The aim of the present study was to investigate the postprandial emptying pattern of indigestible solids in humans and its relation to fed and fasted antral motility. Ten healthy volunteers participated. After an overnight fast they had a standard breakfast. Two sizes of radiopaque markers (ROMs) were given with the test meal; ten cubes each of side measurement 1.5 mm and 3 mm, respectively. Emptying of the ROMs from the stomach was followed by fluoroscopy with simultaneous antral manometry. In six of the subjects, fasting antral manometry was performed on one day and on another day, the emptying of 7 mm cylindrical particles together with 3 mm cubes, in the absence of a gastric tube was recorded. All ROMs were emptied within 5 h (range 1.5–4.5 h). In all subjects, the smaller particles (1.5 mm) showed a slight, insignificant tendency to move from the stomach more rapidly than the larger (3 mm) particles. None of the subjects had an antral phase III before all ROMs were emptied from the stomach. Instead, the typical irregular postprandial pressure activity was present in all subjects until the emptying was completed. Furthermore, the highest postprandial motility index during the emptying study was far below the motility index during phase III, but comparable to the motility index during late phase II. Emptying of the 7 mm particles occurred significantly more slowly at 1.5–2.5 h, but otherwise was similar to the emptying of the smaller particles. There was no difference between emptying of the 3 mm cubes with or without the presence of the tube. Contrary to common opinion, gastric emptying of indigestible solids after a meal can occur unrelated to the antral phase III, at least up to a particle size of 3 mm and perhaps even 7 mm. These findings are of great importance for the evaluation of gastric emptying of indigestible solids, including the pharmacodynamics of orally administered drugs.
Manometric artefacts suggesting compression of the duodenum by the superior mesenteric artery in healthy humans
Authors: Schwartz M. P. , Samsom M. , Smout A. J. P. M.
Published: March 2003

Multi‐channel manometry offers the opportunity to study intestinal motor activity with high spatiotemporal resolution. We report tonic and phasic intraluminal pressure changes in the mid‐portion of the horizontal part of the duodenum. In 10 healthy volunteers, we recorded 2 h of interdigestive duodenal motility using a water‐perfused catheter. The assembly incorporated 12 duodenal sideholes at 1.5‐cm intervals (D1‐D12). Measurement of the antral and duodenal transmucosal potential difference (TMPD) was used to maintain a correct position of the catheter. The incidence of pressure waves (PWs) increased gradually from proximal (D1) to distal (D12) (P < 0.0001), while the mean amplitude of PWs decreased (P < 0.0001). In eight of 10 subjects, the signals recorded from D9 showed tonic pressure elevations with superimposed phasic pressure changes at heart‐rate frequency, comprising 13.8% of total recording time. In the other two subjects, this phenomenon occurred in D8 (9.9% of time). D10 showed a lower incidence of PWs compared with neighbouring sideholes (D6‐D9/D11‐D12) (P < 0.035), with normal amplitudes. Fluoroscopy was performed in three subjects and showed that D9 was located at the midline. In healthy subjects manometric signals recorded from the horizontal part of the duodenum showed localized artefacts, presumably caused by compression by the superior mesenteric artery. In addition, a ‘silent’ region was present just distal to this site, the origin of which is uncertain.
Enhanced intestinal motor response to cholecystokinin in post‐Nippostrongylus brasiliensis‐infected rats: modulation by CCK receptors and the vagus nerve
Authors: Gay J. , Fioramonti J. , Garcia‐Villar R. , Buéno L.
Published: March 2003

The jejunal inflammation induced in rats by the nematode Nippostrongylus brasiliensis is followed by intestinal neuroimmune alterations including mast cell hyperplasia and nerve remodelling. On the other hand, cholecystokinin (CCK) plays a pivotal role in the regulation of intestinal motility. The aim of this study was to determine whether the intestinal motor response to CCK is altered 30 days after infection by N. brasiliensis. Thus, CCK‐8 (50 μg kg–1 intraperitoneally) disrupted the pattern of jejunal migrating myoelectric complexes for a longer time in postinfected rats (95.5 ± 3.5 min) than in controls (48.1 ± 5.1 min). This enhanced jejunal response was also found after oral administration of the potent releaser of endogenous CCK, soybean trypsin inhibitor. In contrast, no alteration of the inhibition of colonic motility by CCK administration was observed. The increased responsiveness of jejunal motility to CCK persisted after mast cell stabilisation or depletion but was prevented by atropine, devazepide and

L‐365260 (CCK‐A and CCK‐B receptor antagonists, respectively) and vagotomy. These results indicate that neuroimmune alterations after N. brasiliensis infection lead to an increased intestinal motility response to CCK that involves a cholinergic mediation, a vagal pathway and alterations in intestinal CCK‐A and CCK‐B receptors.
Galanin suppresses calcium conductance and activates inwardly rectifying potassium channels in myenteric neurones from guinea‐pig small intestine
Authors: Ren J. , Hu H‐Z. , Starodub AL. M. , Wood J. D.
Published: March 2003

Whole‐cell patch‐clamp recording methods were used to investigate the ionic mechanisms underlying the hyperpolarizing action of galanin in enteric neurones. Galanin suppressed calcium current (ICa) and activated inwardly rectifying potassium current (IK,ir) in AH‐type myenteric neurones of guinea‐pig small intestine. Both suppression of ICa and activation of IK,ir were concentration‐dependent, with an EC50 of 1.4 nmol L−1 and 55 nmol L−1, respectively. Pretreatment with pertussis toxin eliminated both actions of galanin, suggesting that both galanin‐induced inhibition of ICa and galanin‐induced activation of IK,ir involved activation of Gi/Go proteins. Both suppression of ICa and activation of IK,ir by galanin were mimicked by the N‐terminal fragment of galanin, galanin‐(1–16) suggesting that the first 16 amino acids of the peptide were sufficient for both actions. The galanin receptor antagonist galantide suppressed the galanin‐induced activation of IK,ir with an EC50 of 16 nmol L−1. However, galantide alone suppressed ICa. The results suggest two mechanisms of action for galanin: one is opening of inwardly rectifying potassium channels and the second is blockade of voltage‐activated calcium channels.
Two‐dimensional high‐resolution motility mapping in the isolated feline duodenum: methodology and initial results
Authors: Lammers W. J. E. P. , Dhanasekaran S. , Slack J. R. , Stephen B.
Published: March 2003

Several types of electrical events occur in the small intestine but their spatial and temporal contributions to overall motility are not clear. In order to quantify local motility in greater detail, a new technique of recording and analysing movements at multiple sites was developed. Use was made of isolated segments of feline duodenum superfused in a tissue bath. Multiple marker dots (20–75) were placed on the serosal surface by applying fine spots of candle soot in rectangular arrays (1–2 mm dot separation). A digital video camera was used to record spontaneous movements of the dots for periods of 10–30 min. After each experiment, 4–6 periods (10–60 s each) of video frames were transferred to a computer (25 fps, 720 × 576 pixels) and the movements of the dots was tracked every 40 ms using custom‐made software. Initial results (eight experiments) show that spontaneous motility is remarkably variable, both in space and time. Three types of movement could be discerned: (i) periodic, rolling or pendular movements, with a frequency of approximately 15 min–1 occurring predominantly in the longitudinal direction; (ii) twitches, wherein a subset of dots were suddenly displaced longitudinally; and (iii) drifts of most of the dots in a circular or oblique direction. All three types of movement occurred throughout every recording session although their relative magnitudes differed greatly from moment to moment. Occasionally, it was possible to detect propagated ‘contractions’ with an apparent velocity of 10 mm s–1. Immobilizing the preparation at one point by inserting a needle through the middle of the array of markers had a negligible effect on the displacements, whereas application of verapamil (10–5  mol L–1) reduced or abolished motility. In summary, we present a new technique to map in detail two‐dimensional motility at the surface of the intestine. Initial results seem to suggest that motility at the serosal surface is not uniform and highly anisotropic.
High‐resolution analysis of the duodenal interdigestive phase III in humans
Authors: Castedal M. , Abrahamsson H.
Published: March 2003

To study the spatial organization of the propagating pressure waves of duodenal phase III, we performed fasting antroduodenal high‐resolution manometry with a 16‐channel catheter in 12 healthy subjects. The phase III pressure waves diverged in an anterograde and retrograde direction from the start site of each pressure wave. The pressure waves maintained this configuration as the activity front moved distally in the duodenum. The start site of the pressure waves moved gradually to a point approximately 12 cm (median) distal to the pylorus and remained at this point for about 40% of the phase III time before moving further distally. The length of retrograde pressure wave propagation increased to 6 cm (median) as the pressure wave origin moved aborally to a point 10–14 cm distal to the pylorus, and then decreased when the origin of pressure waves reached the distal end of the duodenum. Bidirectional pressure waves dominated in both retrograde and anterograde activity fronts. Three pressure‐wave mechanisms behind the duodenal phase IV were observed. Isolated pyloric pressure waves were absent during late duodenal phase III retroperistalsis. Thus, a number of new features of the duodenal phase III‐related motility were observed using high‐temporospatial resolution recordings.
Neuroendocrine control of intestinal mucosal mast cells under physiological conditions
Authors: VERGARA P. , SAAVEDRA Y. , JUANOLA C.
Published: March 2003

Mast cells are involved in the pathogenesis of both allergies to food and inflammatory bowel disorders. In addition, there are several lines of evidence suggesting that mucosal mast cells also respond to intraluminal stimuli. Our aim was to identify neuroendocrine stimuli that could modify mucosal mast cell activity in the rat. Anaesthetized rats were prepared for duodenal perfusion and mast cell activation was measured by analysis of RMCP II concentration in the duodenal perfusate. Either buffered saline solution or a 5% ovalbumin hydrolysate (OVH) solution was infused into the duodenum. Subdiaphragmatic vagotomy or afferent ablation by intraluminal treatment with capsaicin diminished RMCP II concentration in basal conditions and significantly reduced the response to OVH, which in control animals induced a three‐fold increase of the protease. The noradrenergic blockers phentholamine and propranolol significantly diminished RMCP II concentration in basal conditions and completely blocked the response to OVH. Intravenous infusion of cholecystokinin‐related peptides also induced a response of mast cells. However, the response was different depending on the peptide. CCK‐8 induced a slight increase of RMCP II, whereas both CCK‐33 and gastrin induced a significant decrease in mast cell activity. These results show that intraluminal content modulates mucosal mast cell activity by complex mechanisms involving both nervous and endocrine pathway.
Effect of bowel cleansing on colonic transit in constipation due to slow transit or evacuation disorder
Authors: SLOOTS C. E. J. , FELT‐BERSMA R. J. F.
Published: March 2003

Colon transit time measurement with radio‐opaque markers is a method of studying the passage of luminal contents throughout the colon. Overall colonic transit time (CTT), as well as segmental transit times [right (RTT), left (LTT) and rectosigmoid (RSTT)], can be calculated. We hypothesize that CTT is influenced by faecal impaction when the rectum is emptied infrequently. The aim of this study is to investigate the effect of bowel cleansing on colonic transit time in patients with chronic constipation. In 25 women (age 41 years; range 20–65 years) with constipation according to Thompson criteria, CTT measurement was performed in an unprepared situation and repeated after cleansing with 4 L of Klean‐Prep®. Ten healthy female volunteers (age 41 years; range 27–57 years) were used as controls. In constipated patients, CTT decreased from a median 70 h (range 10–130 h) to 48 h (5–94 h) in the cleansed state (P < 0.001). A shortening of transit time was found in all three segments. In 10 patients with slow transit (ST) (CTT > 86 h), CTT decreased from 110 h (range 94–130) to 86 (38–94) (P < 0.001). Five of the 10 patients with ST before bowel cleansing had a CTT below 86 h after cleansing. In female controls, uncleansed CTT and RSTT shortened from 39 h (23 to 62) and 17 h (8–29) to 29 h (17–48) and 10 h (0–20) after bowel cleansing (P=0.058 and P=0.046). Colonic intraluminal contents have a substantial effect on colonic transit. In female controls, bowel cleansing shortened rectosigmoid transit. Women with constipation had faster transit in the cleansed state, however, the distribution of markers was not altered. Despite the effect of bowel cleansing on CTT, it seems unnecessary to prepare the bowel in clinical practice because the differentiation of patients between slow transit constipation and outlet obstruction is not changed. However, because in an infrequent defecation pattern, the influence of faecal impaction is considerable, CTT should be applied with care for critical clinical decisions in the treatment of constipation.
Effect of butyrate on membrane potential, ionic currents and intracellular Ca2+ concentration in cultured rat myenteric neurones
Authors: HASCHKE G. , SCHÄFER H. , DIENER M.
Published: March 2003

Myenteric neurones from 1–10‐day‐old rats were isolated from the small and large intestine by enzymatic digestion with collagenase. Single cells were collected and kept in culture for up to 1 week. After 1–5 days in culture, membrane potential and ionic currents were measured with the whole‐cell patch‐clamp technique. The intracellular Ca2+ concentration was measured with the fura‐2 method. The short‐chain fatty acid butyrate (50 mmol L−1) induced a reversible hyperpolarization of the myenteric neurones by about 10 mV. This hyperpolarization was concomitant with an inhibition of a TTX‐sensitive Na+ current. The hyperpolarization could be suppressed by intracellular application of Cs+, a nonselective K+ channel blocker. Fura‐2 experiments revealed that butyrate induced an increase of the intracellular Ca2+ concentration. The butyrate response was suppressed by thapsigargin, indicating that butyrate stimulates the release of intracellular Ca2+. This release is responsible for the voltage response, because intracellular chelation of Ca2+ inhibited the butyrate induced hyperpolarization. Consequently, butyrate acts on enteric neurones by releasing Ca2+ from intracellular stores with the consequence of the activation of K+ channels, followed by a hyperpolarization.
Gastrointestinal perception: pathophysiological implications
Authors: Azpiroz F.
Published: March 2003

Abstract
 
Physiological gut stimuli during the digestive process are not normally perceived. However, gut stimuli activate a variety of afferent pathways and in some circumstances may induce conscious sensations. Experimental evidence gathered during the past decade suggests that patients with functional gut disorders and unexplained abdominal symptoms may have a sensory dysfunction of the gut, so that physiological stimuli would induce symptoms. Assessment of visceral sensitivity is still poorly developed, but in analogy to somatosensory testing, differential stimulation of visceral afferents may be achieved by a combination of stimulation techniques, which may help to characterize sensory dysfunctions. Visceral afferent input is modulated by a series of mechanisms at different levels of the brain gut axis, and conceivably, a dysfunction of these regulatory mechanisms could cause hyperalgesia. The sensory dysfunction in functional patients seems associated to altered reflex activity, and both mechanisms may interact to produce the symptoms. Evidence of a gut sensory–reflex dysfunction as a common pathophysiological mechanism in different functional gastrointestinal disorders, would suggest that they are different forms of the same process, and that the clinical manifestations depend on the specific pathways affected.
The effect of cholecystectomy on duodenojejunal motility in humans
Authors: Le Blanc‐Louvry I. , Denis P. , DucrottÉ P.
Published: March 2003

Abstract
 
We hypothesized that certain gastrointestinal symptoms following cholecystectomy could be explained by motor disturbances. To test this hypothesis, we compared pre‐ and post‐operative motor patterns between symptomatic and asymptomatic patients after surgery to evaluate whether some motor changes could be induced by gallbladder removal and associated with symptoms. Twenty‐three patients were prospectively evaluated before and 3 months after cholecystectomy. After surgery, 17 patients were asymptomatic and six were symptomatic. Duodenojejunal manometric recordings were performed for 3 h during fasting, then 3 h after a 750‐kcal meal. Patient motor results were compared to those obtained in the duodenojejunum of 20 healthy controls. After surgery, only a few modifications in duodenojejunal motility were observed compared to the preoperative period. Motor changes related to cholecystectomy were increase in phase III amplitude and the absence of progressive decrease of the duodenojejunal motor response after the meal. After surgery, symptomatic patients had a lower postprandial duodenal motility index after the meal than asymptomatic patients (P < 0.03) and more frequent propagated clusters of contractions (PCCs) (P < 0.02). Preoperative motor patterns associated with postoperative symptoms were postprandial only and included a low duodenal motility index (P < 0.03), and a higher number of PCCs (P < 0.02). Removal of the gallbladder has a limited effect on duodenojejunal motility. Few motor differences existed between symptomatic and asymptomatic patients after surgery. However, a low duodenal motor response to a meal and PCCs were often associated with symptoms.
Capsaicin‐sensitive extrinsic afferents are involved in acid‐induced activation of distinct myenteric neurons in the rat stomach
Authors: Schicho R. , Schemann M. , Pabst M. A. , Holzer P. , Lippe I. TH.
Published: March 2003

Abstract Challenge of the rat gastric mucosa with 0.5 mol  L−1 HCl activates nitrergic neurons in the myenteric plexus as visualized by c‐Fos immunohistochemistry. In the present study, we characterized the activated neurons more extensively by their chemical coding and investigated whether a neural pathway that involves capsaicin‐sensitive extrinsic afferents and/or cholinergic neurons transmitting via nicotinic receptors contributes to the activation of myenteric neurons. In multiple labelling experiments, c‐Fos was examined for co‐localization with nitric oxide synthase (NOS), vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), enkephalin (ENK), gastrin‐releasing peptide (GRP), substance P (SP), calbindin D‐28k (CALB) and neurofilament 145 (NF 145). All c‐Fos‐positive neurons were immunoreactive for NOS, VIP, NPY and NF 145, but not for SP, ENK, GRP and CALB. Nerve fibres co‐expressing NOS, VIP and NPY were predominantly found in the external muscle layer and in the muscularis mucosae but rarely in the mucosa. Pre‐treatment with capsaicin or hexamethonium or a combination of both pre‐treatments reduced HCl‐induced c‐Fos expression by 54, 66 and 63%, respectively. Acid challenge of the stomach, therefore, leads to activation of presumably inhibitory motor neurons responsible for muscle relaxation. Activation of these neurons is partly mediated by capsaicin‐sensitive afferents and involves ganglionic transmission via nicotinic receptors.
Myotrophic effects of muscle extracts obtained at different intervals after denervation
Authors: Jimena  , Peña  , Luque  , Ayuso  , Vaamonde
Published: March 2003

A study was made of the myotrophic effects of denervated muscle extracts on normal Wistar rat soleus muscle. Extracts obtained 1 h, 2, 4 and 7 days after sectioning of the sciatic nerve were administered intraperitoneally over five consecutive days. Soleus muscles were routinely processed for morphological and morphometrical analysis using light microscopic techniques. Quantitative differences were observed in the effects of different extracts on total muscle area, fibre cross‐sectional area, mean minimum diameter and number of fibres/area. The greatest myotrophic response was elicited by extracts obtained at 2 and 4 days; differences with respect to controls and extracts obtained at 1 day were significant (P<0.05) for all parameters studied. Statistically significant differences (P<0.05) were also recorded for fibre cross‐sectional area and mean minimum diameter between the 2‐ and 4‐day groups and the 7‐day group. It may thus be concluded that the time elapsing between denervation and extract obtention influences the effect of the extract on normal rat muscle.
A case of multiple system atrophy with hyperglycinaemia due to a selective deficiency of glycine transporter mRNA
Authors: Lane  , Virgo  , Lantos  , De Belleroche
Published: March 2003

A patient presented with features of olivopontocerebellar atrophy and was found to have marked hyperglycinaemia. Severe atrophy of the cerebellum and brain stem was found at post‐mortem, with numerous glial cytoplasmic inclusions (GCIs) in atrophic areas, characteristic of multiple system atrophy. In situ hybridization studies of the spinal cord demonstrated a selective reduction in expression of glycine transporter mRNA. We suggest that the resulting impairment of regulation of glycine concentrations at synaptic level resulted in excitotoxic damage to neurons.
Expression of extracellular matrix degrading enzymes during migration of xenografted brain cells
Authors: Del Bigio  , Tchélingérian  , Jacque
Published: March 2003

Proteolytic enzymes, postulated to create an avenue for cell migration by digestion of host extracellular matrix molecules, have been implicated in neoplastic glial cell migration. A similar process is likely to occur in the developing brain. Fetal rabbit brain fragments transplanted into the striatum of the neonatal Shiverer mouse give rise to cells which migrate from the graft site and differentiate into astrocytes and oligodendrocytes. Proteinase expression by transplanted brain cells was studied using immunohistochemistry and in situ hybridization. Immature donor cells expressed the mRNAs for matrix metalloproteinases (MMP) 1 (collagenase) and 3 (stromelysin). Northern blot analysis of rabbit brain showed that MMP‐1 in particular is expressed in the immature rabbit cerebrum and down‐regulated during maturation. Immature donor cells exhibited immunoreactivity for urokinase plasminogen activator. However, immunoreactivity was also present in maturing neurons. Donor and host astroglia in the vicinity of grafts were immunoreactive for MMP‐2 and tissue‐type plasminogen activator. This expression may represent a reactive phenomenon, not specifically related to cell migration, by mature astrocytes. Based upon our findings, MMP‐1 appears to be a candidate for involvement in migration of immature brain cells in the cerebrum.
Leptomeningeal melanoma and Creutzfeldt–Jakob disease in a patient with chronic lymphocytic leukaemia
Authors: King  , Ryan  , Puranik  , Doey  , Barnes
Published: March 2003

A 78‐year‐old woman with known chronic lymphocytic leukaemia (CLL) was admitted to a psychiatric unit because of rapidly declining cognitive function. Clinical examination also revealed cerebellar signs and she later became akinetic and mute. She deteriorated and died of bronchopneumonia. The histology from the post‐mortem confirmed the presence of CLL in the lymph nodes and she was also found to have diffuse leptomeningeal melanoma. In addition, there was extensive prion protein deposition in the cerebral cortex, but without significant spongiosis. The astrocytosis that was present appeared superficial only. Furthermore, prion protein appeared to be co‐expressed with βA4 in the form of plaques. The patient therefore had evidence of sporadic Creutzfeldt‐Jakob disease (CJD) in addition to meningeal melanoma and CLL. This case further illustrates the importance of employing prion protein immunohistochemistry in suspected cases of CJD, especially where the histology is atypical.
Molecular analysis of alterations of the p18INK4c gene in human meningiomas
Authors: Santarius T. , Kirsch M. , Nikas D. C. , Imitola J. , Black P. M.
Published: March 2003

Meningiomas are common primary brain tumours frequently presenting with deleted and/or mutated NF2 gene located on 22q.1p has been reported as the second most commonly deleted chromosomal region in these neoplasms. A new member of the INK4 family of CDK inhibitors, the p18INK4c gene, has recently been mapped to this chromosomal arm. By virtue of its structural and functional similarities with the p16 gene, p18 has been implicated as a tumour suppressor gene in a variety of cancers. In this paper 40 human meningiomas were analysed for loss of heterozygosity (LOH) at the p18 locus, mutations and inactivating methylation of the p18 gene. LOH at D1S193, D1S463 and D1S211 microsatellite marker loci mapped to 1p32 was detected in 13 of 35 (37%), four of 20 (20%), and six of 24 (25%) tumour samples, respectively. One sample presented with homozygous deletion at D1S193. Mutational analysis using single stranded conformational polymorphism (SSCP) and direct sequencing did not detect any missense mutation but revealed a novel silent mutation, G to T, at coding nucleotide 435. Analysis of HgaI, BsaHI, ScrFI and Eco0109I restriction sites of p18 exon 1 revealed absence of inactivating methylation. Immunohistochemistry with p18 monoclonal antibody detected presence of cytoplasmic p18 staining in 21 of 22 examined samples. One sample did not stain and was shown to carry homozygous deletion at D1S193. Despite the high frequency of LOH at 1p32 microsatellite markers, the lack of genetic and epigenetic aberrations in the p18 gene together with the presence of p18 protein in all but one meningioma samples argues against the role of p18 as a tumour suppressor gene important for meningioma development.
Small heat shock proteins, the cytoskeleton, and inclusion body formation
Authors: Head M. W. , Goldman J. E.
Published: March 2003

Since first being implicated in central nervous system disease 10 years ago, much has been learned concerning the regulation and function of the small heat shock protein αB‐crystallin. Neuropathological, cellular and molecular studies all now point to a functional relationship between αB‐crystallin and intermediate filaments. αB‐crystallin accumulation marks reactive astrocytes in general in a wide variety of disorders and specifically intermediate filament‐based glial inclusion bodies such as Rosenthal fibres found in astrocytes in Alexander's disease. In vitro, αB‐crystallin expression suppresses intermediate filament aggregation and can prevent or reverse experimentally induced glial inclusion body formation. Conversely, dysregulation of glial fibrillary acidic protein expression in vivo results in Rosenthal fibre formation and upregulation of endogenous αB‐crystallin expression. These data and those from studies recently carried out on other tissues strongly suggest that one function of this small heat shock protein is to modulate intermediate filament organization under conditions of physiological stress and neurodegenerative disease.
Tubulin immunoreactive neuronal intranuclear inclusions in the human brain
Authors: Woulfe J. , Munoz D.
Published: March 2003

Intranuclear filamentous and crystalline inclusion bodies have been described in the nuclei of a variety of cells in both normal and pathological states. The functional significance of these structures remains to be elucidated. Moreover, although the proteinaceous nature of these inclusions has been inferred in some histochemical studies, the identity of their constituent proteins remains to be determined. In the present study, immunohistochemistry was used to investigate the presence of intranuclear inclusions in neurones of the human brain which are intensely immunoreactive for the neuronal cytoskeletal protein class III β tubulin. The ability to label these structures immunohistochemically was exploited to investigate the topographic pattern of distribution of these inclusions in the human brain. Intranuclear inclusions were rod‐shaped, polygonal, or irregular in shape. They were present in neurones and ependymal cells. Intranuclear inclusion‐bearing neurones were distributed in an anatomically heterogeneous pattern in the brain. Areas exhibiting relatively high densities of inclusions included the substantia inominata and anterior olfactory nucleus, dentate gyrus, substantia nigra, inferior olivary nucleus, and dentate nucleus of the cerebellum. In addition, intranuclear inclusions were prevalent in neurones in layers II, V, and VI of the cerebral cortex. They were particularly prevalent in the mesial basal temporal neocortex. The relationship of these structures to the intranuclear rods and sheets of the classical microscopists is uncertain. The demonstration that they are composed, at least in part, of tubulin, a major cytoskeletal protein, provides important clues regarding the mechanisms underlying their formation and provides a springboard for developing hypotheses regarding their functional significance. Furthermore, the ability to demonstrate these inclusions immunohistochemically provides an avenue for further studies directed at elucidating the potential involvement of these inclusions in various pathological settings.
Damage control – a possible non‐proteolytic role for ubiquitin in limiting neurodegeneration
Authors: Gray D. A.
Published: March 2003

Ubiquitin can be detected in the neuronal and glial inclusions that are the diagnostic hallmarks of a number of human neurodegenerative diseases. It has been assumed that the presence of ubiquitin signifies the failed attempt of the cell to remove abnormal protein structures, which have been allowed to aggregate. The burden of abnormal protein arising from genetic mutations or cumulative oxidative damage might in the course of time overwhelm the ubiquitin‐proteasome pathway (whose responsibility it is to eliminate misfolded or damaged proteins). However, ubiquitin may still serve a protective purpose distinct from its role in proteolysis. The physical properties of ubiquitin are such that a surface coating of ubiquitin should preclude further growth of the aggregate, prevent non‐productive interactions, and conceal the contents from detection mechanisms that might ultimately kill the cell. This ‘nonstick coating’ hypothesis makes predictions about the nature of the conjugated ubiquitin and the consequences of removing it.
Fas mediates apoptosis in steroid‐induced myopathy of rats
Authors: Lee M. C. , Lee J. S. , Lee M. J. , Lee J. H. , Kim H. I.
Published: March 2003

Recently, apoptotic cell death has been reported in differentiated skeletal muscle, where apoptosis was generally assumed not to occur. To investigate whether apoptosis may contribute to the steroid‐induced myopathy, rats treated with triamcinolone acetonide (TA) for 9 days were sacrificed for detecting apoptosis by in situ end‐labelling (ISEL) and DNA electrophoresis in soleus muscles. Immunohistochemical stainings of Fas antigen and p53 protein were performed to examine whether apoptosis‐related proteins were present in the myopathy. Muscle fibre necrosis and apoptotic myonuclei appeared in soleus muscles following administration of TA, while control muscles showed no evidences for apoptosis. Fas antigen was not detected in control muscles, but expressed in soleus muscles of steroid‐induced myopathy. Some of the Fas antigen‐expressing muscle fibres were positive for ISEL. p53 Protein was not detected in any muscle fibres. These findings indicate that TA can induce apoptosis in differentiated skeletal muscles, and Fas antigen might be partly related to apoptotic muscle death in steroid‐induced myopathy.
Expression of annexin‐1 in multiple sclerosis plaques
Authors: Probst‐Cousin S. , Kowolik D. , Kuchelmeister K. , Kayser C. , Neundörfer B. , Heuss D.
Published: March 2003

This study describes the distribution and identity of annexin‐1 positive cells in the central nervous system in patients with multiple sclerosis (MS). Glucocorticoid‐inducible, anti‐inflammatory properties have been ascribed to annexin‐1, a member of a family of calcium‐binding proteins that are referred to collectively as annexins. We have found annexin‐1 to be spatially associated with active MS lesions and demonstrated a stage‐dependent expression of annexin‐1 in MS plaques. All of the most important pathogenetically involved cells of MS lesions showed a strong annexin‐1 reactivity. Both correlation analysis and double staining procedures suggested annexin‐1 expression in macrophages and perivascular lymphocytes, where a cytoplasmic reactivity was displayed, whereas in activated, gemistocytic astrocytes it was also concentrated close to the plasma membrane. Although the exact roles of annexin‐1 in this setting are still to be determined, a possible contribution to anti‐inflammatory processes might be suggested.
Co‐expression of trkA and p75 neurotrophin receptor in extracranial olfactory neuroblastoma cells
Authors: Zhao S.‐P. , Zhou X.‐F.
Published: March 2003

Olfactory neuroblastoma (ON, esthesioneuroblastoma) is a high‐grade malignant tumour of neuronal origin. Little is known about the neurobiological behaviour of this tumour. Ten cases of ON and five cases of nasopharyngeal carcinoma were examined for expression of trkA and p75 neurotrophin receptor (p75NTR) using immunohistochemistry and double labelling fluorescence. We found that all ON tissues from 10 cases expressed both trkA and p75NTR at different levels. Double staining revealed that almost all trkA‐immunoreactive ON cells also contained p75NTR immunoreactivity. By contrast, no trkA or p75NTR immunoreactivity was detected in nasopharyngeal carcinoma cells from five patients. These results suggest that nerve growth factor may play a role in the generation of ON and staining of trkA and p75NTR may assist in the diagnosis of ON.
Molecular genetic analysis of the TP53, PTEN, CDKN2A, EGFR, CDK4 and MDM2 tumour‐associated genes in supratentorial primitive neuroectodermal tumours and glioblastomas of childhood
Authors: Kraus J. A. , Felsberg J. , Tonn J. C. , Reifenberger G. , Pietsch T.
Published: March 2003

Supratentorial primitive neuroectodermal tumours (sPNETs) are malignant central nervous system tumours of childhood which are histologically characterized by poorly differentiated neuroepithelial cells with the capacity for divergent differentiation into glial, neuronal, myogenic or melanotic lines. The histological differential diagnosis between sPNET and glioblastoma multiforme (GBM) may be difficult, particularly as GBMs can sometimes demonstrate a poorly differentiated PNET‐like phenotype. To identify molecular genetic markers that may distinguish sPNET and GBM, we investigated 12 cerebral sPNETs and six GBMs from paediatric patients for genetic alterations of the TP53, PTEN, CDKN2A, EGFR, CDK4 and MDM2 genes, as well as for allelic loss on chromosome arms 10q and 17p. Mutations of the TP53 tumour suppressor gene were found in one of 12 sPNETs (8%) and two of six GBMs (33%). None of the sPNETs but two of six GBMs (33%, including one GBM with a TP53 mutation) showed allelic losses on chromosome arm 17p. PTEN mutations were detected in one of 12 sPNET (8%) and one of six GBMs (17%). None of the sPNETs and GBMs carried a homozygous deletion involving the CDKN2A tumour suppressor gene. No amplification of the EGFR, CDK4 or MDM2 proto‐oncogenes was detected. Taken together, our results indicate that paediatric GBMs differ from sPNETs by a higher incidence of allelic losses on 17p and TP53 mutations. In addition, the patterns of genetic alterations in sPNETs and paediatric GBMs appear to be distinct from those in cerebellar medulloblastomas and adult GBMs, respectively.
The role of microglial activation in the resolution of CNS lesions
Authors: Willis C. L. , Lynch N. J. , Schwaeble W. J. , Ray D. E.
Published: March 2003

We are developing a rat model to investigate the relationship between cell death, the inflammatory response and blood–brain barrier function. A single dose of S‐α‐chlorohydrin induces early astrocyte swelling and loss (6–18 h), followed by neuronal death (36–48 h) and barrier dysfunction (24 h‐6 d) with no primary immune involvement. Using in situ hybridization we looked for increased expression of C1q; the first component of the classical complement pathway and a sensitive marker of microglial activation previously shown to be up regulated within 1 h of a global ischaemic insult (Schwaeble et al. J Immunol 2000; 164: 5446). Our results suggest that microglial activation is a comparatively late event commencing at 36 h and appears to be prompted by neuronal rather than astrocytic death, while barrier function is restored in parallel with removal of cell debris and extravasated protein. It appears that microglial activation may not be causing barrier breakdown but instead promoting rapid resolution of the lesion by limiting the inflammatory response. We are currently investigating the time course of pro‐ and anti‐inflammatory marker expression and its role in lesion resolution.
Towards a molecular definition of microglia
Authors: Moran L. B. , Thykjaer T. , Orntoft T. F. , Graeber M. B.
Published: March 2003

Introduction:  Microglia account for at least 10% of all glial cells in the CNS. Morphologically they are unique, forming highly ramified and perpendicularly branching cell processes. In response to pathological stimuli, microglia show considerable plasticity and may assume a macrophage phenotype. Here we report transcriptome data on normal rat microglial cells in vitro.

Material and methods:  Microglial cultures of high purity (>95%) were prepared from newborn rat brains. RNA was used for comparative expression profiling on two different Affymetrix GeneChips, the rat neurobiology U34 microarray, and the more comprehensive U34A chip.

Results:  Analysis of the expression data was performed using GeneSpring. Only genes exhibiting expression values >2 signal/control ratio were included. Microglia were found to express 8% (107) of the genes on the neurobiology array and 14% (1203) of the genes on the U34A chip, respectively. Among the expressed ‘functional motifs’, groups of immunomodulatory molecules including interleukin (1,18), complement and MIF featured prominently in agreement with the view that microglia represent an intrinsic immune network in the CNS. However, novel products of microglia, e.g. embigin, were also found.

Conclusions:  We provide a tentative molecular definition of microglia.
SCIP/Oct‐6, Krox‐20 and desert hedgehog mRNA expression during CNS remyelination by transplanted olfactory ensheathing cells
Authors: Smith P. M. , Sim F. J. , Franklin R. J. M.
Published: March 2003

Olfactory ensheathing cells (OECs) are able to generate myelin sheaths following transplantation into areas of CNS demyelination that are remarkably similar to those made by Schwann cells despite their separate developmental origin. The transcriptional control of Schwann cell myelination has been well documented, but whether the same transcription factors are also expressed when OECs assume a myelinating phenotype is not known. We have addressed this question by using a transplantation approach to generate myelinating OECs and examined the expression of SCIP/Oct‐6 and Krox‐20 mRNA by in situ hybridization. We also examined the expression of desert hedgehog (Dhh), a Schwann cell derived signalling molecule responsible for regulating the development of the connective tissue elements in peripheral nerve. Our results indicate that both Krox‐20 and Dhh mRNA are strongly expressed by transplanted OECs, with SCIP mRNA present at much lower levels. The expression of Krox‐20 relative to the expression of P0 mRNA by the transplanted OECs is consistent with it playing a similar role in OEC myelination to that in Schwann cell myelination, while the expression of Dhh suggests a possible mechanism for the diverse morphologies that OECs adopt following transplantation into the damaged CNS.
Loss of chromosome 10, retinoblastoma and deleted‐in‐colon‐carcinoma (DCC) proteins in glioblastomas
Authors: Hilton D. A. , Love S. , Penny M. , Pobereskin L.
Published: March 2003

Introduction:  Glioblastomas have a median survival of 9–12 months. However, some patients die within a few weeks of diagnosis and others may survive for 2 years or more. To try to predict survival more accurately, we have evaluated a number of morphological, immunohistochemical and molecular markers in a retrospective series of glioblastomas.

Material and methods:  Paraffin sections from 107 consecutive glioblastomas diagnosed between 1993 and 1997 were included in the study. All cases were reviewed and the presence of calcification or oligodendroglioma‐like areas noted. Sections were immunostained with commercial antibodies to retinoblastoma and DCC proteins and subjected to in situ hybridization with probes to chromosomes 12 and 10.

Results:  Loss of retinoblastoma and DCC protein expression was seen in 20% and 71% of glioblastomas respectively. Loss of retinoblastoma protein expression correlated with poor outcome (P = 0.045). 64% of glioblastomas showed loss of chromosome 10 but this did not have a significant association with survival. The five tumours with oligodendroglioma‐like areas had a median survival of 70 weeks, compared with 27 weeks for those without (P = 0.014).

Conclusion:  In this study, age, loss of retinoblastoma protein and a lack of oligodendroglioma‐like areas were predictors of significantly shorter survival in glioblastomas.
The expression of the EGF receptor family and their ligands in human medulloblastomas
Authors: Collins V. P. , Ichimura K. , Liu L.
Published: March 2003

Introduction:  Little is known about the molecular processes behind the development of medulloblastomas. While many chromosomal abnormalities have been more or less consistently observed, only a few cellular pathways have been identified as being targeted. These include the Hedgehog/patched signalling pathway (involving PTCH, PTCH2, SSH and SMOH) and the Wnt signalling pathway (involving APC, and β‐catenin). Amplification of N‐myc is associated with a bad prognosis.

Material and methods:  We examined the expression of the Epidermal Growth Factor Receptor family and nine of their ligands in a series of 48 medulloblastomas and supratentorial primitive neuroectodermal tumours (PNETs) by quantitative RT‐PCR, Western blot and immunocytochemistry.

Results:  The most striking finding was the high levels of expression of erbB4 transcript – in some cases greater that 250 times that found in normal cerebellum. ErbB4 transcript levels greater than 10 times that of cerebellum were seen in 73% of the series. ErbB2 and erbB3 transcript levels exceeding 10 times that of cerebellum were seen in 35% of cases. Only two cases had overexpression of EGFR/erbB1 at these levels. Ligands (Epiregulin/Betacellulin/NDF_/NDF_1/NDF_2) for erbB4 were coexpressed in 74% (26/35) of the cases with high erbB4 expression. Only one case showed no expression of erbB4 and its ligands.

Conclusions:  The findings suggest that various forms of autocrine, paracrine, and juxtacrine stimulation through these receptors may contribute to the malignant phenotype of medulloblastomas.
Characterization of a novel oncofetal cell surface glycoprotein
Authors: Mulligan K. A. , Gillespie H. , Mirakhur M. , McCormick D.
Published: March 2003

The principal reason for the poor prognosis associated with malignant astrocytomas is recurrence as a result of invasion of surrounding brain parenchyma by tumour cells. As part of an investigation into the mechanisms of astrocytoma invasion, we raised monoclonal antibodies (Mab) against cell surface proteins expressed by an anaplastic astrocytoma cell line (G‐CCM). One of the antibodies (MQ1 Mab) recognizes a novel cell surface glycoprotein (MQ1) with a molecular weight of 200 kDa. N‐terminal sequencing revealed no sequence homology with any known mammalian protein. In vitro MQ1 protein expression was found on astrocytomas and fetal astrocytes, with the level of expression increasing with astrocytoma malignancy and decreasing with fetal astrocyte maturity. Immunohistochemistry on histologically normal and neoplastic brain tissue demonstrated that MQ1 protein expression is restricted to astrocytomas (n = 52). Other primary brain tumours tested and normal brain cells were MQ1 negative. A G‐CCM cDNA expression library was synthesized and screened with the MQ1 antibody. Two positive clones were isolated and sequencing data demonstrated that both have a high degree of homology with Jagged1, a human Notch ligand. Subsequent protein studies indicate that the MQ1 protein has homology with, but is not identical to Jagged1. Knocking out MQ1 protein expression with antisense oligonucleotides induced apoptosis in the G‐CCM cell line.
Correlation of single photon emission computed tomography with pathology and seizure outcome in children undergoing epilepsy surgery
Authors: Cross J. H. , Hartley L. , Harkness W. , Harding B. , Neville B. , Gordon I.
Published: March 2003

Introduction:  Single photon emission computed tomography (SPECT) imaging regional cerebral blood flow (rCBF) can help localize the seizure focus in partial epilepsies during presurgical evaluation. Few studies have explored the possible relationship between preoperative SPECT and underlying pathology, or any relationship to postsurgical outcome.

Study group:  Thirty‐five children with medically intractable epilepsy undergoing resective surgery between the ages of 11 months and 18 years had presurgical ictal and interictal rCBF and post surgery follow up of 3–6 years.

Results:  Pathological examination revealed 13 to have hippocampal sclerosis (HS): of these 11 had relatively low interictal rCBF perfusion on the side of seizure onset, and eight had hyperfusion ictally. Eight children had morphological evidence of cortical dysplasia: all had a localizing ictal rCBF concordant with the area resected whereas only six demonstrated localized reduction in perfusion on interictal rCBF. All three patients with Rasmussens encephalitis had informative rCBF scans, concordant with the seizure focus. However, infarct, tumours and nonspecific pathology demonstrated poor localization of the seizure focus. No SPECT parameter correlated independently with outcome, although overall the HS group had the best outcome, particularly those with localizing ictal SPECT.

Comment:  Ictal SPECT appears predictive of underlying cortical dysplasia. Although in this small group of HS in children, ictal SPECT added little to interictal SPECT for seizure localization, it may be useful in the prediction of outcome. SPECT adds little to the evaluation of children being considered for hemispherectomy over and above the abnormalities detectable on MRI scan.