bluuebunny/crossref_metadata_2025 huggingface dataset:
A plasmid‐encoded regulator couples the synthesis of toxins and surface structures in Bacillus anthracis
Authors: Mignot Tâm , Mock Michèle , Fouet Agnès
Published: March 2003

Transcription of the major Bacillus anthracis virulence genes is triggered by CO2, a signal believed to reflect the host environment. A 180 kb plasmid, pXO1, carries the anthrax toxin genes and the genes responsible for their regulation, pagR and atxA; the latter encodes a major trans‐activator. It has long been known that pXO1 genes have major effects on the physiology of B. anthracis, probably through regulatory cross‐talk between plasmid and chromosomal genes. Accordingly, we found that the chromosomal S‐layer genes, sap and eag, are regulated by pXO1 genes so that only eag is significantly expressed in the presence of CO2. This effect results from the product of pagR acting as the most downstream element of a signalling cascade initiated by AtxA. In vitro evidence showed that PagR is a transcription factor that controls the S‐layer genes by direct binding on their promoter regions. This work provides evidence that AtxA is a master regulator that co‐ordinates the response to host signals by orchestrating positive and negative controls over genes located on all genetic elements.
Proinflammatory signalling stimulated by the type III translocation factor YopB is counteracted by multiple effectors in epithelial cells infected with Yersinia pseudotuberculosis
Authors: Viboud Gloria I. , So Stephane Shu Kin , Ryndak Michelle B. , Bliska James B.
Published: March 2003

Type III secretion systems are used by several pathogens to translocate effector proteins into host cells. Yersinia pseudotuberculosis delivers several Yop effectors (e.g. YopH, YopE and YopJ) to counteract signalling responses during infection. YopB, YopD and LcrV are components of the translocation machinery. Here, we demonstrate that a type III translocation protein stimulates proinflammatory signalling in host cells, and that multiple effector Yops counteract this response. To examine proinflammatory signalling by the type III translocation machinery, HeLa cells infected with wild‐type or Yop–Y. pseudotuberculosis strains were assayed for interleukin (IL)‐8 production. HeLa cells infected with a YopEHJ– triple mutant released significantly more IL‐8 than HeLa cells infected with isogenic wild‐type, YopE–, YopH– or YopJ– bacteria. Complementation analysis demonstrated that YopE, YopH or YopJ are sufficient to counteract IL‐8 production. IL‐8 production required YopB, but did not require YopD, pore formation or invasin‐mediated adhesion. In addition, YopB was required for activation of nuclear factor kappa B, the mitogen‐activated protein kinases ERK and JNK and the small GTPase Ras in HeLa cells infected with the YopEHJ– mutant. We conclude that interaction of the Yersinia type III translocator factor YopB with the host cell triggers a proinflammatory signalling response that is counteracted by multiple effectors in host cells.
Identification of a protein, YneA, responsible for cell division suppression during the SOS response in Bacillus subtilis
Authors: Kawai Yoshikazu , Moriya Shigeki , Ogasawara Naotake
Published: March 2003

A knock‐out mutant of the dinR gene that encodes the SOS regulon repressor in Bacillus subtilis was constructed. The yneA, yneB and ynzC genes transcribed divergently from the dinR gene were strongly induced in mutant cells. Northern hybridization analyses revealed that these genes collectively form an operon and belong to the SOS regulon. The simultaneous deletion of dinR and yneA suppressed the filamentous phenotype of the dinR mutant. Furthermore, although yneA is suppressed in the wild‐type cell in the absence of SOS induction, artificial expression of the YneA protein using an IPTG‐inducible promoter resulted in cell elongation. Disruption of yneA significantly reduced cell elongation after the induction of the SOS response by mitomycin C in dinR+ cells. These results indicate that the YneA protein is responsible for cell division suppression during the SOS response in B. subtilis. Localization of the FtsZ protein to the cell division site was reduced in dinR‐disrupted or yneA‐expressing cells, further suggesting that the YneA protein suppresses cell division through the suppression of FtsZ ring formation. Interestingly, the B. subtilis YneA protein is structurally and phylogenetically unrelated to its functional counterpart in Escherichia coli, SulA.
Productive interaction between the chromosome partitioning proteins, ParA and ParB, is required for the progression of the cell cycle in Caulobacter crescentus
Authors: Figge Rainer M. , Easter Jesse , Gober James W.
Published: March 2003

In Caulobacter crescentus the partitioning proteins ParA and ParB operate a molecular switch that couples chromosome partitioning to cytokinesis. Homologues of these proteins have been shown to be important for the stable inheritance of F‐plasmids and the prophage form of bacteriophage P1. In C. crescentus, ParB binds to sequences adjacent to the origin of replication and is required for the initiation of cell division. Additionally, ParB influences the nucleotide‐bound state of ParA by acting as a nucleotide exchange factor. Here we have performed a genetic analysis of the chromosome partitioning protein ParB. We show that C. crescentus ParB, like its plasmid homologues, is composed of three domains: a carboxyl‐terminal dimerization domain; a central DNA‐binding, helix–turn–helix domain; and an amino‐terminal domain required for the interaction with ParA. In vivo expression of amino‐terminally deleted parB alleles has a dominant lethal effect resulting in the inhibition of cell division. Fluorescent in situ hybridization experiments indicate that this phenotype is not caused by a chromosome partitioning defect, but by the reversal of the amounts of ATP‐ versus ADP‐ bound ParA inside the cell. We present evidence suggesting that amino‐terminally truncated and full‐length, wild‐type ParB form heterodimers which fail to interact with ParA, thereby reversing the intracellular ParA‐ATP to ParA‐ADP ratio. We hypothesize that the amino‐terminus of ParB is required to regulate the nucleotide exchange of ParA which, in turn, regulates the initiation of cell division.
The MAPKK kinase SteC regulates conidiophore morphology and is essential for heterokaryon formation and sexual development in the homothallic fungus Aspergillus nidulans
Authors: Wei Huijun , Requena Natalia , Fischer Reinhard
Published: March 2003

Environmental signals can be transduced into intracellular responses by the action of MAP kinase cascades. Sequential phosphorylation results in the transient activation of a MAP kinase, which in turn activates certain transcription factors and thus a set of pathway‐specific genes. Many steps in this cascade are conserved, and homologues have been discovered from yeast to human. We have characterized the MAPKK kinase, SteC, a homologue of Saccharomyces cerevisiae Ste11, in the filamentous fungus Aspergillus nidulans. The 886‐amino‐acid‐long protein shares the highest similarity to Neurospora crassa Nrc‐1. Deletion of the gene in A. nidulans results in a slower growth rate, the formation of more branched hyphae, altered conidiophore morphology, an inhibition of heterokaryon formation and a block of cleistothecium development. The gene is transcriptionally activated during asexual development and controls the phosphorylation of two putative MAP kinases.
Involvement of chloride channels in the receptormediated activation of longitudinal colonic muscle
Authors: KÖLBEL  , HOLTMANN  , MCROBERTS  , SCHÖLER  , AENGENVOORDT  , SINGER  , MAYER
Published: March 2003

In gastrointestinal smooth muscle, intracellular Cl– is maintained at levels higher than its electrochemical equilibrium. Therefore, Cl– efflux through receptor‐mediated opening of Cl– channels should result in membrane depolarization and may be sufficient to activate voltage‐sensitive calcium channels (VSCCs). To determine the contribution of Cl– channels to receptor‐mediated contraction of the longitudinal muscle layer of the rabbit distal colon, we studied the mechanical response of muscle strips to substance P, carbachol and potassium depolarization following the depletion of Cl–i, and in the presence of the Cl– channel blocker 5‐nitro‐2‐(3‐phenylpropylamino)‐benzoate (NPPB). A 60‐min incubation of tissues in a HEPES‐buffered solution in which NaCl had been replaced by Na isethionate (or Na gluconate) in equimolar amounts resulted in disappearance of phasic contractions, and in a partially reversible reduction of the tonic response to substance P and carbachol, but not to KCl depolarization. When the agonist was applied to tissues in control solution, or to Cl–‐depleted tissues in a solution in which Na+ was acutely replaced in equimolar amounts by N‐methyl‐
D‐glucosamine, the mechanical response to substance P and carbachol was almost abolished. Acute Na+ replacement alone without prior Cl– depletion did not abolish phasic contractions, but reduced the tonic response to substance P and carbachol. Similar to the effect of Cl– depletion, incubation of tissues in NPPB (6.6 × 10–5M) reduced the tonic response to substance P and carbachol, and abolished phasic contractions. These findings are consistent with a contribution of a Cl– channel to the receptor‐mediated activation of colonic smooth muscle. In addition, the data suggest that␣transient Cl– channel mediated depolarizations may play a role in the generation of phasic contractions.
Effect of truncal vagotomy on gallbladder bile kinetics in conscious dogs
Authors: Muramatsu  , Sonobe  , Tohara  , Tanaka  , Mizumoto  , Ibuki  , Suzuki  , Itoh
Published: March 2003

Previous studies on the effects of vagotomy on gallbladder (GB) motility have yielded conflicting results. The aim of this study was to evaluate the effects of vagotomy on GB motility and bile kinetics using a new method. Twelve dogs were divided into two groups of six (control and pyloroplasty) and, 4 weeks later, underwent truncal vagotomy. A catheter secured in the GB fundus was used to monitor GB volume. After injecting polyethylene glycol (PEG) into the GB, combined measurements of GB volume and PEG concentration enabled GB emptying and bile kinetics to be estimated. Seven and five of the 12 vagotomized dogs were classified as having large and normal fasting GB volumes, respectively. Postprandial GB emptying was impaired when the fasting GB volume was enlarged. In the fasting state, bile kinetics of vagotomized dogs were significantly smaller than the control values. The emptying ability of the GB of vagotomized dogs with large fasting GB volumes was reduced considerably both in the postprandial and the fasting states. Such retention of bile in the GB after vagotomy may facilitate cholesterol crystal nucleation and stone growth.
Progressive alterations in circular smooth muscle contractility in TNBS‐induced colitis in rats
Authors: Hosseini  , Goldhill  , Bossone  , Piñeiro‐Carrero  , Shea‐Donohue
Published: March 2003

The present study was designed to investigate inflammation‐induced changes in smooth muscle responses to acetylcholine and the tachykinins that may contribute to the abnormal motility associated with inflammatory bowel disease. Colitis was induced in male Sprague–Dawley rats by intrarectal administration of trinitrobenzenesulphonic acid in ethanol. After either 4 h (acute) or 7 days (chronic) the distal colon was taken for in vitro measurement of smooth muscle tension and histological assessment. Acute colitis featured injury and neutrophilic infiltration confined to the mucosa while chronic inflammation showed marked injury, lymphocytic infiltration and muscle thickening. Acute inflammation increased responses to substance P and acetylcholine but decreased responses to neurokinin A. The enhanced response to substance P was dependent on nerves, while the decreased response to neurokinin A reflected a reduction in activity at the level of the smooth muscle. In the saline group, there was evidence of cholinergic interaction with substance P, but not neurokinin A. Substance P modulation of cholinergic nerves was absent in acute inflammation. Responses to all neurotransmitters were decreased in the chronic stage. These data demonstrate progressive changes in the smooth muscle function during acute and chronic colitis that may contribute to the abnormal motility associated with inflammatory bowel disease.
Computer analysis of prolonged lower oesophageal sphincter pressure recordings
Authors: Van Herwaarden M. A. , Samsom M. , Wolf C. , Leong I. S. , Smout A. J. P. M.
Published: March 2003

The aim of the study was to validate a recently developed computer program for the analysis of prolonged recordings of lower oesophageal sphincter pressure. Thirty 1‐hour stretches were selected from sets of 24‐h pressure signals recorded from the pharynx, oesophagus, lower oesophageal sphincter (LOS) and stomach in 10 ambulant patients with gastrooesophageal reflux disease. Three experienced investigators visually analysed end‐expiratory LOS pressures and transient lower oesophageal sphincter relaxations (TLOSRs), using published criteria. A computer program was developed for calculation of an end‐expiratory pressure curve and detection of TLOSRs using the same criteria. Although the results showed an maximum deviation from the mean of 11.1% and 14.8% for manually calculated LOS pressures and visually detected TLOSRs, respectively only 62.1% of the detected TLOSRs were detected by all three observers. LOS pressure as measured by the computer closely approximated the mean of the LOS pressures calculated by the three observers. Although the total number of TLOSRs was comparable to that assessed by visual analysis, the computer detected only 46% of the TLOSRs detected by each observer and 56.8% of the TLOSRs detected by all observers. It is concluded that automated calculation of end‐expiratory LOS pressure is feasible and yields reliable results, whereas automated detection of TLOSRs could not be satisfactorily accomplished. Our study showed that improvement of computer algorithms for TLOSR detection is desirable. However, the previously described criteria for detection of TLOSRs are insufficiently precise; further refinement of these criteria will be necessary to reduce the large discrepancies between the outcome of detection of TLOSRs by computer and by humans, and to reduce the equally large discrepancies between the results of detection by different human observers.
Does age play a role in mylohyoideus muscle function?
Authors: Jégo A. , Chassagne P. , Landrin‐Dutot I. , Capet C. , Havard C. , Hellot M. F. , Weber J. , Doucet J. , Bercoff E. , Benichou J.
Published: March 2003

Because swallowing disorders are frequent in the elderly, we assessed the relationship between age and mylohyoideus muscle contraction, which is an important component of the initial step in swallowing. In a prospective study, 120 subjects without any personal history of diseases associated with swallowing disorders underwent electromyographic recording (EMG) of mylohyoideus muscle activity. Four groups of equal size (n=30) were defined according to age (≤50, 51–70, 71–85, >85 years). The frequency and duration of mylohyoideus muscle asynchronisms were compared among the four groups. The comparison of mylohyoideus muscle EMG among groups did not show a significant difference in the mean number of asynchronisms, in duration per subject or in the frequency of long‐lasting asynchronisms. Asynchronisms were a very frequent event, observed in 98% of subjects, and were mostly short, lasting less than 0.1 s in 90% of subjects. In healthy elderly patients, there was no linear relationship between the mean duration of asynchronisms and ageing. The occurrence of one or more long‐lasting asynchronisms or of at least six asynchronisms during a sequence of 10 successive swallows should be considered to be abnormal.
Effect of sildenafil, a phosphodiesterase‐5 inhibitor, on oesophageal peristalsis and lower oesophageal sphincter function in cats
Authors: Zhang X. , Tack J. , Janssens J. , Sifrim D. A.
Published: March 2003

The propagation of oesophageal peristaltic contractions and lower oesophageal sphincter (LOS) relaxation depends on neural release of nitric oxide (NO) which acts to increase intracellular cGMP. Sildenafil, a phosphodiesterase‐5 inhibitor that increases cGMP, reduces basal LOS pressure in patients with achalasia. We investigated the effect of sildenafil on the propagation of oesophageal contractions and LOS relaxation in the cat. Oesophageal manometry was performed in five cats under light sedation. Peristaltic contractions were monitored at 1, 2, 3, 4 and 8 cm proximal to the LOS, at the LOS using a Dent sleeve, and at 3 cm distal to the upper oesophageal sphincter. Swallow‐induced oesophageal contractions and LOS relaxation were recorded during 30 min before and 30 min after intravenous administration of sildenafil. Sildenafil reduced the amplitude of oesophageal contractions only in the smooth muscle oesophagus. The latency from swallow to distal oesophageal contractions was significantly delayed. LOS pressure was significantly reduced but the relaxation nadir was not modified by sildenafil. Sildenafil has profound effects on oesophageal motility: it modifies propagation and amplitude of oesophageal contractions and reduces LOS pressure. Slowing down the propagation of contractions in the transitional zone between the striated and smooth muscle can be a useful tool in patients with segmental aperistalsis or intermittent simultaneous contractions, while the effect on the LOS can benefit patients with achalasia.
Lipidized mature neuroectodermal tumour of the cerebellum with myoid differentiation
Authors: González‐Cámpora  , Weller
Published: March 2003

We describe a case of a lipidized cerebellar tumour in a 67‐year‐old woman with immunocytochemical evidence of neurocytic, astrocytic, and in addition, striated muscle cell differentiation. A review of the literature on lipidized cerebellar tumours shows that they present in adults (mean age 58.8 years); they tend to occur in the hemispheric or paramedian regions of the cerebellum and are hypodense on CT scan and MRI. Histologically they are well differentiated and share some common features, such as extensive lipidization, low mitotic rate and an absence of pleomorphism, necrosis and capillary endothelial proliferation. The present case emphasizes the occurrence of astrocytic and striated muscle cell components in these tumours. Although the number of reported cases is limited they appear to have a better prognosis than the conventional form of adult medulloblastoma. It seems therefore that the term lipidized mature neuroectodermal tumour, rather than lipidized medulloblastoma, would be a more appropriate term for these tumours.
MIB‐1(Ki‐67) index and transforming growth factor‐alpha (TGFα) immunoreactivity are significant prognostic predictors for meningiomas
Authors: Hsu  , Efird  , Hedley‐Whyte
Published: March 2003

Mitotic index >6, proliferating cell nuclear antigen (PCNA) index >5%, high tumour grade and absence of progesterone receptors (PR) are significant predictors for poor outcome in meningiomas. Since MIB‐1 (Ki‐67) is a more specific cell proliferation marker, and overexpression of TGF‐alpha is also associated with tumour progression, we compared the prognostic significance of these factors with the other indices. Intracranial meningiomas from 21 men and 36 women (age 54.5±1.7, mean±sem) were classified as 24 benign, 24 atypical and nine malignant. Twenty‐one of the 57 tumours recurred (mean interval to recurrence was 57.3±13.1 months). The mean follow‐up period for patients without tumour recurrence was 81.9±8.7 months. MIB‐1 labelling index (LI) was expressed as percentage of labelled nuclei to total tumour nuclei counted in the most densely labelled areas. Analysis of variance revealed significant differences between tumour grades for MIB‐1 labelling indices (0.75±0.21 for benign, 3.2±0.57 for atypical, 6.04±1.48 for malignant; P≤0.0066), and between malignant and non‐malignant meningiomas for TGFα staining scores (P≤0.029). MIB‐1 LI also correlated with mitotic and PCNA indices (P≤0.0001), but not with age of the patients. Male patients had higher tumour MIB‐1 LI than females (P≤0.0128). Univariate analysis indicated that MIB‐1 LI>3%, TGFα score >4 (scoring scale 0–5), mitotic index >6, and negative PR status were significant factors for worse outcome. Higher MIB‐1 LI, TGFα score and mitotic index as continuous variables were also significant negative predictors. With multivariate analysis, both MIB‐1 LI and TGFα score remained significant factors when paired with all other variables: TGFα or MIB‐1 LI, respectively, mitosis, PCNA, tumour grade, PR status, age, sex, postoperative radiation therapy. We conclude that MIB‐1 LI and TGFα score are important independent prognostic indicators for patients with meningiomas.
The acute inflammatory response in CNS following injection of prion brain homogenate or normal brain homogenate
Authors: Betmouni  , Perry
Published: March 2003

The neuropathological hallmarks of end‐stage prion disease are vacuolation, neuronal loss, astrocytosis and deposition of PrPSc amyloid. We have also shown that there is an inflammatory response in the brains of scrapie‐affected mice from 8 weeks post‐injection. In this study we have investigated the acute CNS response to the intracerebral injection of scrapie‐affected brain homogenate. The ME7 strain of scrapie (Neuropathogenesis Unit, Edinburgh) was used, and control mice were injected with brain homogenate derived from normal C57BL/6 J mice. One microlitre of 10% w/v ME7 (n=33) and normal brain homogenate (n=28) was injected stereotaxically into the right dorsal hippocampus. Cryostat sections of brains taken at 1, 2, 5, 7, 14 and 28 days post‐injection were examined histologically for neuronal loss, and immunocytochemically to study the inflammatory response. This study shows that ME7 is not acutely neurotoxic in vivo. There is also no difference (anova) in the inflammatory response, which peaked between 2 and 5 days and resolved by 4 weeks after intracerebral injection of either ME7 or normal brain homogenate. The well circumscribed inflammatory response seen previously at 8 weeks is therefore a consequence of a disease process rather than a surgical artefact. This disease process may be related to a localized accumulation of PrPSc sufficient to stimulate an inflammatory response which in turn may contribute to neuronal loss. The role of the inflammatory response in chronic neurodegeneration can be usefully studied using this mouse model of prion disease, and this will undoubtedly shed light on the pathogenic mechanisms underlying other chronic neurodegenerative diseases.
Overexpression of S100β in Down’s syndrome: correlation with patient age and with β‐amyloid deposition
Authors: Royston  , McKenzie  , Gentleman  , Sheng  , Mann  , Griffin  , Mrak
Published: March 2003

S100β is an astrocyte‐derived uritotrophic’ cytokine which has been implicated in the pathogenesis of Alzheimer’s disease. S100β overexpression by plaque‐associated astrocytes correlates with growth of abnormal (strophic’) neurites in β‐amyloid plaques, one of the major neuropathological hallmarks of Alzheimer’s disease. As the characteristic neuropathological changes of Alzheimer’s disease are virtually universal in middle‐aged Down’s syndrome patients, studies of Down’s syndrome patients provide a unique opportunity to investigate the pathophysiological processes underlying the development of Alzheimer‐type neuropathological changes. Computerized morphometric analysis was used to quantify astrocyte activation and astrocytic expression of S100β, and to correlate these with β‐amyloid deposition, in a clinically well‐characterized cohort of Down’s syndrome subjects, aged 13–65 years. There were significant positive correlations between S100β expression and patient age, and between S100β expression and cerebral cortical β‐amyloid deposition. Moreover, the numbers of activated (enlarged) astrocytes overexpressing S100β showed a significant correlation with the numeric density of β‐amyloid plaques, from the youngest to the oldest ages and within age ranges where pathology is most florid, while no such relationship was found between the numbers of small, non‐activated S100β‐immunoreactive cells and numerical density of β‐amyloid plaques. These correlations, together with established functions of S100β, are consistent with the idea that S100β overexpression promotes β‐amyloid plaque formation and progression in Down’s syndrome.
Increased expression of gelatinases and alteration of basement membrane in rat soleus muscle following femoral artery ligation
Authors: Frisdal E. , Teiger E. , Lefaucheur J. ‐P. , Adnot S. , Planus E. , Lafuma C. , D’Ortho M. ‐P.
Published: March 2003

Acute severe muscle ischaemia is characterized by significant remodelling of basement membranes of myofibres. It was hypothesized that peripheral artery insufficiency is accompanied by similar muscle extracellular matrix (ECM) changes involving matrix metalloproteinase gelatinases. Using a model of femoral artery ligation, both gelatinase activity and basement membrane component degradation were studied in hindlimb skeletal muscles. SDS–PAGE zymography of muscle homogenates showed that acute moderate ischaemia was followed by a significant transient increase in expression of 72‐ and 92‐kDa gelatinases during 48 h; the latter probably originated from inflammatory cells. In situ zymography showed that this increase occurred chiefly at the periphery of myofibres. Immunolocalization demonstrated 72‐kDa gelatinase in interspaces and at the periphery of myofibres, and suggested that this enzyme may explain the gelatinolytic activities found by in situ zymography. Type IV collagen and laminin staining showed that the gelatinase expression increase correlated with dramatic basement membrane component alterations. Our data show that even moderate ischaemia results in significant muscle basement membrane remodelling due to matrix degrading enzymes matrix metalloproteinases (MMP) gelatinases.
Role of axon‐deprived Schwann cells in perineurial regeneration in the rat sciatic nerve
Authors: Popović M. , Bresjanac M. , Sketelj J.
Published: March 2003

The role of Schwann cells (SC) in perineurial regeneration after nerve injury has not yet been resolved. It was hypothesized that SC alone are able to induce at least partial morphological restoration of the destroyed orthotopic perineureum (PN). To test the hypothesis, a permanently denervated segment of the rat sciatic nerve was made acellular by freeze‐thawing, except in its most proximal part where non‐neuronal cells were left intact. Restoration of the frozen segment by these cells was examined by electron microscopy and immunohistochemistry of the SC marker, S‐100 protein, 4 and 8 weeks after injury. The PN regenerated from undifferentiated fibroblast‐like cells. In the presence of migrant SC without axons, regenerated cells in the place of the former PN were stacked in several layers and, in accordance with the hypothesis, partially expressed typical features of the perineurial cells (PC): pinocytotic vesicles, short fragments of basal lamina and tight junctions. Migrant SC induced formation of pseudo‐minifascicles even in the epineurium. In these, SC organized the adjacent fibroblasts into a multilayered circular sheath, and induced their partial differentiation towards perineurial cells. Further experiments demonstrated that regenerating axons are required for complete morphological differentiation of the regenerated perineurial cells either in the orthotopic PN or in minifascicles.
Molecular genetic analysis of archival gliomas using diagnostic smears
Authors: Walker C. , Joyce K. , Du Plessis D. , Machell Y. , Sibson D R. , Broome J.
Published: March 2003

Investigation of the clinical significance of genetic alterations in gliomas requires molecular genetic analysis using samples from retrospective or prospective clinical studies. However, diagnostic tissue is often severely limited and because of fixation, paraffin‐embedded tissues (PET) contain degraded DNA. Intra‐operative cytological preparations (smears) archived after diagnosis may represent an additional source of clinical material for genetic analysis. In this study, tissue samples were obtained by precision microdissection of archived diagnostic smears from 20 cases (1961–1999). All samples produced polymerase chain reaction (PCR) products for the β globin gene, but the most recent samples amplified best and gave longer amplimers. For six cases, direct comparison was made between samples microdissected from smears and the corresponding PET. Samples from smears showed improved PCR performance and similar alleles on microsatellite marker analysis. One case, with smears of uninvolved cortex and tumour tissue available for microdissection, showed allelic imbalance at 10q23 on the basis of the smear results alone. PCR products from smears were shown to be suitable for direct sequence analysis (p53 gene). A PTEN mutation, found previously in an anaplastic astrocytoma by analysis of PET, was detected in the corresponding diagnostic smear. The results of this study indicate that tissue samples microdissected from diagnostic intra‐operative cytological preparations may be suitable for molecular genetic analysis of gliomas.
High topoisomerase IIα expression associates with high proliferation rate and and poor prognosis in oligodendrogliomas
Authors: Miettinen H. E. , Järvinen T. A. H. , Kellner U. , Kauraniemi P. , Parwaresch R. , Rantala I. , Kalimo H. , Paljärvi L. , Isola J. , Haapasalo H.
Published: March 2003

The role of molecular markers predicting the prognosis and the selection of patients for further adjuvant therapies is not well established in oligodendroglioma patients. A potential prognostic as well as a therapeutically predictive factor, topoisomerase IIα (topoIIα), is a molecular target for certain cytotoxic drugs. Its expression has been shown to correlate with the prognosis in a number of different cancers and with the chemosensitivity of cancer cells in vitro. The expression of topoIIα was evaluated immunohistochemically in 59 oligodendrogliomas and in 29 mixed gliomas with a predominating oligodendroglioma component by the use of a tissue microarray technique. In the gliomas, the percentage of topoIIα immunopositive cells protein expression varied from 0.0 to 49.1% (5.2 ± 8.3%, mean± SD). In oligoastrocytomas, the mean topoIIα score was significantly higher in the oligodendroglioma than in the astrocytoma component of the tumour (5.37 ± 5.58% vs. 1.89 ± 2.49%, P = 0.018). A significant association was found between the high proportion of topoIIα positive cells and high grade of the tumour (P < 0.0001), high tumour proliferation rate (P < 0.0001), p53 overexpression (P = 0.01) and high expression of tumour suppressing retinoblastoma protein (P = 0.023). TopoIIα expression was not associated with the age or sex of patient, and the rate of apoptosis. TopoIIα expression associated highly significantly with patient prognosis; a significantly higher proportion of patients with low rather than with high topoIIα score was alive at the end of the 5‐year follow‐up (P = 0.03). Cox analysis was used to demonstrate that topoIIα had an independent prognostic value for survival (P = 0.034). In conclusion, high topoIIα expression characterizes oligodendrogliomas and oligoastrocytomas which are poorly differentiated, have high proliferation rate, and has prognostic value for overall survival of these patients. Therefore, topoIIα may be a useful marker for better targeted selection of poor prognosis oligodendroglioma patients for adjuvant therapy.
Tau‐associated neuropathology in ganglion cell tumours increases with patient age but appears unrelated to ApoE genotype
Authors: Brat Daniel J. , Gearing Marla , Goldthwaite Patricia T. , Wainer Bruce H. , Burger Peter C.
Published: March 2003

Ganglion cell tumours, including gangliogliomas and gangliocytomas, are low grade neoplasms with a mature neuronal component. Ganglion cells within these lesions occasionally exhibit neurodegenerative changes including neurofibrillary tangles (NFT) similar to those in Alzheimer's disease. The frequency and spectrum of degenerative pathology in these lesions have not been defined, nor has their relation to patient age or factors such as apolipoprotein E (ApoE) genotype that predispose to Alzheimer's disease. We studied 72 ganglion cell tumours (61 gangliogliomas, 11 gangliocytomas) from patients 7 months to 72‐years‐old. Haematoxylin and eosin (H&E), silver stains (Hirano method) and immunohistochemistry for tau, α‐synuclein and β‐amyloid were performed on formalin‐fixed, paraffin‐embedded tissue from surgical specimens. Tau‐and silver‐positive NFT and neuropil threads (NPT) were present in four of 26 ganglion cell tumours from patients over 30‐years‐old (ages 31, 38, 50, and 58 years). Neuronal granulovacuolar degeneration (GVD) was noted in five of 26 tumours from patients over 30‐years‐old (mean, 48 years). NFT, NPT, and GVD were not seen in ganglion cell tumours from patients under 30‐years‐old[0/46]. Cytoplasmic argentophilic bodies distinct from NFT were present in five of 26 tumours from patients over 30‐years‐old and in two of 46 under 30 years. Neither α‐synuclein positive neuronal inclusions nor β‐amyloid immunoreactivity was noted in ganglion cell tumours from any age group. The distribution of ApoE genotypes was similar among those tumours that contained tau‐associated neuropathology and those that did not. Neurodegenerative changes are uncommon in ganglion cell tumours, but increase in frequency with patient age. GVD, tau‐positive NFT and NPT, and argentophilic bodies occur more often in ganglion cell tumours from patients over 30‐yrs‐old, but do not appear to be associated with a specific ApoE genotype.
Defective assembly of sarcoglycan complex in patients with β‐sarcoglycan gene mutations. Study of aneural and innervated cultured myotubes
Authors: Fanin M. , Angelini C.
Published: March 2003

Mutations in the sarcoglycan (SG) genes cause autosomal recessive muscular dystrophies. The absence of each SG complex component in muscle impairs the proper assembly of the entire SG complex, resulting in sarcolemmal damage. We investigated the consequences of β‐SG gene mutations in cultured muscle from two β‐SG mutated patients, and analysed each individual SG protein expression by cross‐sectional immunocytochemistry and Western blot in aneural and innervated myotubes. Patients' muscle biopsy showed total loss of SG complex; however, a limited amount of β‐SG was detected in aneural and innervated myotubes, where the protein was localized to the plasma membrane. This paradoxical β‐SG expression can be attributable to antibody cross‐reaction or to the expression of an unknown SG isoform specific of immature muscle. In our cultured myotubes, the other components of the SG complex were absent, suggesting that β‐SG gene mutations result in a defective assembly of the entire SG complex in early stages of muscle development, and that the role of β‐SG is crucial for the normal structure and/or function of the SG complex in the sarcolemma.
Differences in their interactions with astrocytes distinguish the behaviour of olfactory ensheathing cells and Schwann cells
Authors: Lakatos A. , Barnett S. C. , Franklin R. J. M.
Published: March 2003

The olfactory ensheathing cell (OEC) is able to remyelinate axons in demyelinating lesions and support regrowth of transected axons following transplantation. Schwann cells (SCs) share these repair properties but have limitations imposed on their behaviour by the presence of astrocytes. Since OECs exist alongside astrocytes in the olfactory bulb we have hypothesized that they have advantages over SCs in transplant‐mediated CNS repair, because of their compatibility with astrocytes. In this study we have tested this hypothesis by comparing the interactions between astrocytes and either SCs or OECs using a range of in vitro assays. We have shown that (1) astrocytes undergo hypertrophy when in contact with SCs but not with OECs; (2) astrocytes and SC aggregate in defined nonoverlapping domains in mixed coculture, whereas astrocytes and OECs freely intermingle; (3) SCs spend less time in contact with astrocytes than do OECs; and (4) a larger number of OECs migrate over astrocytes monolayers compared with SCs although the distance migrated is the same. Taken together, these data support the hypothesis that transplanted OECs will integrate more extensively in astrocytic environments than will transplanted SCs.
A role for cerebrovascular disease in determining the pattern of β‐amyloid deposition in Alzheimer's disease
Authors: Yow H. Y. , Weller R. O.
Published: March 2003

Introduction:  The pattern of β‐amyloid (Aβ) deposition in cerebral amyloid angiopathy (CAA) in Alzheimer's disease (AD) suggests that Aβ is eliminated along perivascular interstitial fluid drainage pathways. The age at which accumulation of Aβ in the brain becomes significant in AD coincides with the development of cerebrovascular disease (CVD) and increasing rigidity of artery walls through arteriosclerosis.

Hypothesis:  The distribution of Aβ deposits in Alzheimer brains is influenced by CVD.

Materials and methods:  Paraffin sections of frontal, parietal, temporal and occipital lobes from six cases with Alzheimer's disease were stained for reticulin and by immunocytochemistry for Aβ and GFAP.

Results:  Three distinct patterns of Aβ deposition were seen in relation to cortical blood vessels: (i) early deposition of Aβ in cortical parenchyma was related to individual cortical arterial territories; (ii) severe capillary amyloid angiopathy and an absence of Aβ plaques were associated with thromboembolic occlusion of the feeding artery; (iii) Aβ plaques were abundant in areas devoid of capillary amyloid angiopathy.

Conclusions:  The pattern of Aβ deposition corresponds to individual intracortical arterial territories, and hence periarterial ISF drainage territories. Cerebrovascular disease influences the pattern of Aβ deposition within brain parenchyma and in vessel walls in individual arterial territories. Failure of periarterial drainage of Aβ from the brain may be related to cerebrovascular disease and is possibly due to altered arterial pulsations.
A rat model of neonatal post‐haemorrhagic ventricular dilatation
Authors: Cherian S. , Silver I. A. , Love S. , Whitelaw A. , Thoresen M.
Published: March 2003

Introduction:  Post‐haemorrhagic ventricular dilatation (Phvd) complicates 30% of cases of severe intraventricular haemorrhage (Ivh) in preterm infants. The majority require shunt surgery and are disabled. The mechanism by which Ivh leads to Phvd is not understood, and no satisfactory neonatal model exists. We have developed a neonatal rat model of Phvd to study the mechanisms of Phvd.

Methods:  Mixed sex, 7‐day‐old (P7) Wistar rats were anaesthetized with halothane and placed in a stereotactic frame. Ivh was simulated by injection of citrated rat blood into alternate lateral ventricles on two consecutive days (P7, P8). Survivors were killed on P22 and their brains fixed by immersion in 4% formaldehyde. H&E‐stained 5 µm sections were examined for pathological changes. Glial reaction was assessed by immunohistochemistry for glial fibrillary acidic protein, and ventricular area in standard coronal planes through the cerebrum was measured using Nih Image software.

Results:  Increased ventricular size, focal ependymal disruption, reactive changes and accumulation of haemosiderin in scattered parenchymal cells were observed in 30% of the experimental animals. Injection of blood also caused a narrow zone of dense periventricular gliosis.

Conclusion:  This rat pup model of Phvd may be useful for ascertaining the mechanism of post‐haemorrhagic ventricular dilatation.
CADASIL in monozygotic twins
Authors: Kalimo H. , Viitanen M. , Carlström C. , Nordberg A. , Bronge L.
Published: March 2003

Introduction:  The cause of the highly variable clinical course in CADASIL is unknown, independent of the type of mutation.

Patients and clinical findings:  The age of onset in the mother of monozygotic twins was 70 years. At 73 years MMSE was 22 with impairment of executive functions. T2w MRI showed grade D hyperintensities and T1w MRI infarcts in basal ganglia. She died at 73 years. Her geminus‐B twin son had first symptoms at 39 years, 30 years earlier than his mother. At 47 years he scored 29 in MMSE. T2w MRI disclosed grade C hyperintensities and T1w MRI infarcts in basal ganglia. Detection of GOM in dermal arteries established CADASIL diagnosis. The A twin is subjectively healthy at 48 years with MMSE 30. His T2w MRI showed grade B hyperintensities, but no infarcts in T1w MRI. In PET, the B twin's CBF was more markedly diminished than that of the A twin.

Conclusion:  The clinical course in CADASIL can vary markedly despite the same gene defect or even identical genome. No anticipation or gender difference has been reported. The B twin is a smoker. Elucidation of reasons for the variation may reveal important pathogenetic factors.
Tau load is associated with apolipoprotein E genotype and the amount of amyloid β protein, Aβ40, in sporadic and familial Alzheimer's disease
Authors: Thaker U. , McDonagh A. M. , Iwatsubo T. , Lendon C. L. , Pickering‐Brown S. M. , A. Mann D. M.
Published: March 2003

U. Thaker, A. M. McDonagh, T. Iwatsubo, C. L. Lendon, S. M. Pickering‐Brown and D. M. A. Mann (2003) Neuropathology and Applied Neurobiology 29, 35–44

 Tau load is associated with apolipoprotein E genotype and the amount of amyloid β protein, Aβ40, in sporadic and familial Alzheimer's disease

The total amount of hyperphosphorylated tau protein (p‐tau load), present as neurofibrillary tangles (NFTs), neuropil threads or plaque neurites, was quantified in the frontal cortex of 109 cases of sporadic Alzheimer's disease (AD) and 35 cases of familial AD due to missense mutations in the presenilin‐1, presenilin‐2 and amyloid precursor protein genes. p‐tau load was inversely correlated with age at onset of illness in both sporadic and familial AD but not with duration of disease. There was no difference in p‐tau load between cases of familial AD and others with sporadic AD, matching the familial cases for apolipoprotein E (APO E) genotype. However, p‐tau was greater in cases of familial and sporadic AD in the presence of APO E ɛ4 allele and increased with gene dose. Conversely, p‐tau load tended to be lower when ɛ2 allele was present. In sporadic AD, tau load was highly significantly correlated with amyloid β40 (Aβ40), but not Aβ42(43), load. These data indicate that the burden of pathological tau deposited in the brain in both familial and sporadic AD is favoured in the presence of APO E ɛ4 allele and also related to the amount of Aβ40, this also being higher when ɛ4 allele is present. Aβ40 plaques are rich in microglial cells and it is possible that p‐tau pathology in AD is triggered by reaction of microglial cells to the presence of Aβ40 and not this peptide directly.
Maternal factors and breast cancer risk among young women
Authors: Sanderson  , Williams  , Daling  , Holt  , Malone  , Self  , Moore
Published: March 2003

The results from previous studies have provided evidence to support the hypothesised association between intrauterine oestrogen exposure and subsequent risk of breast cancer. Information has not been available to study this relationship for several perinatal factors thought to be related to pregnancy oestrogen levels. Data collected from the mothers of women in two population‐based case–control studies of breast cancer in women under the age of 45 years (510 case mothers, 436 control mothers) who were diagnosed between 1983 and 1992 in three western Washington counties were used to investigate further the relationship between intrauterine oestrogen exposure and risk of breast cancer. A pregnancy weight gain of 25–34 pounds was associated with breast cancer risk (odds ratio [OR] = 1.5; 95% confidence interval [CI] 1.1, 2.0); however, women whose mothers gained 35 pounds or more were not at increased risk. Use of antiemetic medication in women with any nausea and vomiting (OR = 2.9; 95% CI 1.1, 8.1) and use of diethylstilboestrol (DES) (OR = 2.3; 95% CI 0.8, 6.4) appeared to be positively associated with breast cancer risk. The results from this study provide limited support for the hypothesis that in utero oestrogen exposure may be related to subsequent breast cancer risk among young women.
Organisational variation, satisfaction, and women’s time investment in prenatal care
Authors: Dye  , Wojtowycz
Published: March 2003

This study measured the amount of time women spent obtaining prenatal care, and related that time spent to satisfaction with care. Women with Medicaid coverage (n = 364) were interviewed about several parameters related to their most recent prenatal visit: (1) how long it took them to get to the visit; (2) how long they waited upon arrival; and (3) how much time they spent with practitioners during the visit. Women were asked questions regarding satisfaction with the most recent visit, and with their care in general. They received care from four sources: private practitioners, community health centres (CHCs), hospital clinics and health department clinics. Women’s satisfaction with care decreased as time spent with practitioners decreased, relative to time spent travelling and waiting. Those obtaining care from CHCs were more likely to have shorter waiting times and longer visit times than women obtaining care from other sources. Women spent approximately 3 h during pregnancy in face‐to‐face contact with practitioners. Satisfaction with care is closely associated with women’s relative time investment in obtaining care. Both satisfaction and time investment parameters vary widely by source of prenatal care.
Ethnic differences in the growth of low‐birthweight infants
Authors: Seed  , Ogundipe  , Wolfe
Published: March 2003

Differences in growth were investigated among ethnic groups in low‐birthweight babies (<2500 g or <32 weeks gestation) at birth and at 2–3 years. This prospective study was based on data for all 3091 low‐birthweight live births in the South East Thames Region, UK, over a 1‐year period, surviving to discharge from hospital. Weights were recorded at birth and at 2–3 years for 998 babies, and head circumferences for 859. These were compared with the UK 1990 reference standards. Ethnic differences were adjusted for parity, multiple birth, smoking and alcohol during pregnancy, mother’s height, weight and age, marital status, partner’s support and social class. At 2–3 years, there was substantial average catch‐up growth only for the weight of infants of 32 weeks’ gestation. Babies <32 weeks gestation had fallen behind. Head circumferences had failed to keep up or had fallen behind for both groups. The ethnic groups had similar birthweight standard deviation scores (SDS). At 2–3 years, Black babies of <32 weeks’ gestation had gained in weight and head circumference compared with White babies (adjusted difference in weight SDS: 0.71, [95% CI 0.28, 1.13]). Asian babies of at least 32 weeks’ gestation had smaller heads than White, a difference that increased with time. It was concluded that ethnic differences in the growth of low‐birthweight infants are related to gestational age. Although most of the babies born at <28 weeks’ gestation were close to their birthweight reference standards, only the Black infants had maintained their position at 2–3 years. Black infants, particularly when born preterm, tend to put on more weight than White.