bluuebunny/crossref_metadata_2025 huggingface dataset:
SeqA‐mediated stimulation of a promoter activity by facilitating functions of a transcription activator
Authors: Słomińska Monika , Konopa Grażyna , Ostrowska Justyna , Kędzierska Barbara , Grzegorz Węgrzyn  , Węgrzyn Alicja
Published: March 2003

It was demonstrated recently that the SeqA protein, a main negative regulator of Escherichia coli chromosome replication initiation, is also a specific transcription factor. SeqA specifically activates the bacteriophage λpR promoter while revealing no significant effect on the activity of another λ promoter, pL. Here, we demonstrate that lysogenization by bacteriophage λ is impaired in E. coli seqA mutants. Genetic analysis demonstrated that CII‐mediated activation of the phage pI and paQ promoters, which are required for efficient lysogenization, is less efficient in the absence of seqA function. This was confirmed in in vitro transcription assays. Interestingly, SeqA stimulated CII‐dependent transcription from pI and paQ when it was added to the reaction mixture before CII, although having little effect if added after a preincubation of CII with the DNA template. This SeqA‐mediated stimulation was absolutely dependent on DNA methylation, as no effects of this protein were observed when using unmethylated DNA templates. Also, no effects of SeqA on transcription from pI and paQ were observed in the absence of CII. Binding of SeqA to templates containing the tested promoters occurs at GATC sequences located downstream of promoters, as revealed by electron microscopic studies. In contrast to pI and paQ, the activity of the third CII‐dependent promoter, pE, devoid of neighbouring downstream GATC sequences, was not affected by SeqA both in vivo and in vitro. We conclude that SeqA stimulates transcription from pI and paQ promoters in co‐operation with CII by facilitating functions of this transcription activator, most probably by allowing more efficient binding of CII to the promoter region.
Membrane localization of the ToxR winged‐helix domain is required for TcpP‐mediated virulence gene activation in Vibrio cholerae
Authors: Crawford J. Adam , Krukonis Eric S. , DiRita Victor J.
Published: March 2003

ToxR is a bitopic membrane protein that controls virulence gene expression in Vibrio cholerae. Its cytoplasmic domain is homologous to the winged helix–turn–helix (‘winged helix’) DNA‐binding/transcription activation domain found in a variety of prokaryotic and eukaryotic regulators, whereas its periplasmic domain is of ill‐defined function. Several genes in V. cholerae are regulated by ToxR, but by apparently different mechanisms. Whereas ToxR directly controls the transcription of genes encoding two outer membrane proteins, OmpU and OmpT, it co‐operates with a second membrane‐localized transcription factor called TcpP to activate transcription of the gene encoding ToxT, which regulates transcription of cholera toxin (ctxAB) and the toxin‐co‐regulated pilus (tcp). To determine the requirements for gene activation by ToxR, different domains of the protein were analysed for their ability to control expression of toxT, ompU and ompT. Soluble forms of the cytoplasmic winged‐helix domain regulated ompU and ompT gene expression properly but did not activate toxT transcription. Membrane localization of the winged helix was sufficient for both omp gene regulation and TcpP‐dependent toxT transcription, irrespective of the type of periplasmic domain or even the presence of a periplasmic domain. These results suggest that (i) the major function for membrane localization of ToxR is for its winged‐helix domain to co‐operate with TcpP to activate transcription; (ii) the periplasmic domain of ToxR is not required for TcpP‐dependent activation of toxT transcription; and (iii) membrane localization is not a strict requirement for DNA binding and transcription activation by ToxR.
Visceral perceptions and gastric myoelectrical activity in healthy women and in patients with bulimia nervosa
Authors: KOCH K. L. , BINGAMAN S. , TAN L. , STERN R. M.
Published: March 2003

Bulimia nervosa remains a common eating disorder in young women. Little is known about upper gastrointestinal symptoms or gastric motility in patients with bulimia nervosa. The aim of this study was to measure gastric myoelectrical activity and hunger/satiety and stomach emptiness/fullness before and after a non‐nutrient water load and solid‐phase gastric emptying in hospitalized patients with bulimia nervosa (n = 12) and in healthy women (n = 13). Gastric myoelectrical activity was measured by means of cutaneous electrodes; visual analogue scales were used to measure perceptions of hunger/satiety and stomach emptiness/fullness. Before and after a standard water load the bulimia patients reported significantly greater stomach fullness and satiety compared with control subjects (P < 0.01). The percentage of gastric myoelectrical power in the normal 3 cpm range was significantly less in bulimics compared with controls. Power in the 1–2 cpm bradygastria range was significantly greater in bulimia patients before and after the water load compared with the control subjects (P < 0.05). Solid‐phase gastric emptying studies using radio‐isotope‐labelled scrambled eggs showed the lag phase was shortened in the bulimic patients (16 ± 4 min vs 31 ± 4 min in controls, P < 0.01), but the percentage of meal emptied at 2 h was similar to control values. In conclusion: bulimia patients had exaggerated perceptions of stomach fullness and satiety in response to water; and abnormal gastric myoelectrical activity and accelerated lag phase of gastric emptying were objective stomach abnormalities detected in hospitalized patients with bulimia nervosa.
Mechanisms of gastro‐oesophageal reflux in the ferret
Authors: BLACKSHAW L. A. , STAUNTON E. , DENT J. , HOLLOWAY R. H. , MALBERT C. H.
Published: March 2003

Transient lower oesophageal sphincter (LOS) relaxation is the major mechanism of gastro‐oesophageal reflux in humans – an event unassociated with swallowing. Mechanisms involved in triggering transient LOS relaxation are poorly understood, and their further study requires a small animal model. In this study we aimed to establish methods for prolonged ambulant oesophageal manometry in ferrets, and to determine motor events associated with reflux episodes and their triggering by different gastric nutrient loads. Forty‐two studies were performed on nine ferrets with chronic cervical oesophagostomies, through which a manometric assembly was introduced and secured to a collar, which incorporated a microphone for detection of swallows. The assembly included a gastric feeding channel, one gastric and four oesophageal manometric sideholes, a 2.5‐cm‐long LOS sleeve sensor, and an oesophageal pH electrode. Intragastric infusions were given over 2 min, the first after a 30‐min control recording period, and in 29/42 studies, a second infusion was given 60 min later. Infusions were either 25 mL 10% dextrose solution, pH 3.5 (22 studies), 25 mL triglyceride emulsion (Intralipid) pH 3.5 (11 studies), or 25 mL air (nine studies). Episodes of oesophageal acidification were absent before gastric infusions. After infusion, 2.1 ± 0.2 episodes occurred over the first 30 min. After glucose infusion, 15/18 acidification episodes (83%) occurred during transient LOS relaxation, and 3/18 (17%) occurred after gradual (< 1 mmHg sec−1) downward drifts in basal LOSP to < 2 mmHg. After lipid infusion two acidification episodes occurred, both during transient LOS relaxation. Mean duration of transient LOS relaxation was 8.0 ± 0.4 sec. All infusions increased occurrence of transient LOS relaxation to a similar extent, each of which ended with primary peristalsis. We conclude that gastric infusion of glucose, lipid and gas are all effective in provoking gastro‐oesophageal reflux in ferrets. Reflux occurs through similar mechanisms to those seen in humans, i.e. increased triggering of transient LOS relaxation. The conscious ferret is therefore an appropriate model for future studies of manipulation of mechanisms giving rise to gastro‐oesophageal reflux.
Validation of antroduodenal motility measurements made by echo‐planar magnetic resonance imaging
Authors: WRIGHT  , EVANS  , GOWLAND  , MANSFIELD
Published: March 2003

Echo planar imaging, a development of magnetic resonance imaging, can produce snapshot images of the stomach and antroduodenal segment in as little as 64 msec and can be more useful than conventional techniques when assessing motility. The aim of this study was to compare antroduodenal motility measured by simultaneous perfused tube manometry and echo planar imaging. Ten volunteers were studied following the ingestion of 500 mL water or 500 mL porridge. Antroduodenal images, with acquisition times of 130 msec, were taken at 3‐sec intervals, synchronized with motility traces and presented as a split‐screen video. This allowed direct visual comparison of gastric wall movement and motility to be made. Contractions were confined to either the stomach or the duodenum or propagated across the antroduodenal segment. Over 4550 images were available for analysis. A larger number of propagated contractions were recorded with echo planar imaging in both water (P = 0.03) and food (P = 0.02) groups, whereas manometry detected a greater number of isolated duodenal pressure waves (P = 0.005). The contraction rate for water and food studies was similar, but direct visualization indicated that the manometric technique under‐detected propagated events. The ability of echo planar imaging to record antroduodenal contractile activity provides a new insight into the role of occlusive and nonocclusive contractions during gastric emptying.
Temporal distribution of neuronal and inducible nitric oxide synthase and nitrotyrosine during colitis in rats
Authors: MIAMPAMBA  , SHARKEY
Published: March 2003

Nitric oxide (NO) has been implicated in the pathogenesis of inflammatory bowel disease since increased NO production is observed in this disease. NO can react with superoxide to generate peroxynitrite which causes and/or exacerbates colitis. Peroxynitrite, in turn, nitrates tyrosine residues to form nitrotyrosine which can be identified immunohistochemically. We investigated the distribution of neuronal and inducible nitric oxide synthase (iNOS) and nitrotyrosine over time in experimental colitis. Colitis was induced by intracolonic administration of trinitrobenzene sulphonic acid (TNBS) in rats. Animals were killed 1, 2, 7 and 14 days after treatment. Myeloperoxidase activity was used as an index of inflammation, and tissues were examined using immunohistochemistry. Neuronal NOS immunoreactivity was present throughout the colon, and was only slightly reduced 1 day after the induction of colitis. Conversely, iNOS immunoreactivity almost absent in controls dramatically increased in the mucosa and submucosa at the early stages of inflammation. iNOS was present in monocytes and macrophages and also another unidentified cell type. Seven and 14 days after the induction of colitis, iNOS was also found in nerves in the circular muscle and in the myenteric plexus. Nitrotyrosine immunoreactivity present in a few cells in the normal mucosa also increased 1 day after the induction of colitis and decreased thereafter. The pattern of distribution of nitrotyrosine immunoreactivity was distinct from that of iNOS. The increase of iNOS expression at the early stage of inflammation may play a role in causing tissue injury via peroxynitrite formation. The expression of iNOS seen in the enteric nerves in the later stage of inflammation correlates temporally with the beginning of tissue repair and with the re‐innervation and compensatory growth of nerves. NO may potentially play a physiological as well as pathological role in experimental colitis.
Effect of endotoxin on opossum oesophageal motor function
Authors: Park H. , Calrk E. , Cullen J. J. , Conklin J. L.
Published: March 2003

Endotoxin induces nitric oxide (NO•) synthase and alters gastrointestinal functions. We explored the effect of lipopolysaccharide (LPS) on oesophageal motor function at 6, 12, 24, and 48 h. The effects of inhibiting inducible NO• synthase (iNOS) were studied 12 h after administration of LPS with/without aminoguanidine (AG). Oesophageal manometry was performed and tissue bath studies were performed with muscle strips from the oesophagus and lower oesophageal sphincter (LOS). Plasma nitrite/nitrate concentrations were determined. The amplitudes of peristaltic pressure waves, resting LOS pressure and the percentage LOS relaxations were diminished by LPS. AG attenuated the decrease in amplitude of oesophageal pressure waves, LOS pressure, and percentage relaxation of LOS brought about by LPS. LPS decreased electrical field stimulation (EFS)‐induced relaxation of LOS muscle. AG attenuated this decrease in LOS relaxation. The off‐response of transverse oesophageal muscle strips was decreased, and AG antagonized this effect. Plasma concentrations of nitrite/nitrate were increased. The increase in plasma nitrite/nitrate was attenuated by AG. These studies support the hypothesis that endotoxin modulates oesophageal motor function by increasing NO production and suggest that this results from the induction of iNOS.
Role of NK2 receptors in gastric barosensitivity and in experimental ileus in rats
Authors: Toulouse M. , Fioramonti J. , Maggi C. , Buéno L.
Published: March 2003

This study was performed to evaluate the role of tachykinin NK2 receptors in gastric barosensitivity and in postsurgical intestinal atony, using a selective NK2 antagonist (MEN 11420). Gastric distensions were performed in rats equipped with a gastric balloon and electrodes implanted in the neck muscles. Ileus was produced by laparotomy and caecum palpation in rats previously prepared with electrodes implanted on the proximal jejunum. Fifteen minutes before gastric distension or laparotomy, the animals received MEN 11420 (10, 100 or 200 μg kg−1 intravenously) or saline. The first distending pressure to increase the integrated neck electromyogram > 100% was considered the pain threshold. MEN 11420 (100 μg kg−1) increased significantly pain threshold (20.5 ± 1.2 vs. 17.0 ± 0.8 mm Hg) but did not modify gastric volumes at the three doses tested. Abdominal surgery was followed by a total inhibition of jejunal spiking activity lasting 80.4 ± 18.7 min. MEN 11420 (10 and 100 μg kg−1) shortened the duration of motor inhibition by 36 and 39%, and induced a premature recovery of the phase III of migrating myoelectric complex at the lowest dose tested (130 ± 32 vs. 192 ± 28 min). We conclude that NK2 receptors, probably located on afferent fibres, are involved in gastric barosensitivity and in postsurgical intestinal atony.
Morphometric and biomechanical remodelling in the intestine after small bowel resection in the rat
Authors: DOU Y. , LU X. , ZHAO J. , GREGERSEN H.
Published: March 2003

The short‐bowel syndrome is a clinical condition caused by intestinal resection. As intestinal adaptation occurs after resection, it can be used as a model for studying morphometric and biomechanical remodelling in the small intestine and to get a better understanding of the pathophysiology of the short‐bowel syndrome. The resected rats had a 67% resection of jejunum and ileum. Control animals underwent no operation (nonoperated controls) or an ileal transection with subsequent end‐to‐end anastomosis (sham‐resected controls). The animals were followed for up to 4 weeks after the operation. Changes in biomechanical properties were studied in terms of residual strain (the internal strain remaining when all external loads are removed), opening angle and stress–strain relations referenced to the zero‐stress state (the cut‐open state where external and internal stresses are released). The resected animals gained less weight than the controls. The intestinal length and diameter increased more in the resected groups than the control groups (P < 0.05), resulting in a larger absorptive surface. Resection induced profound gross morphometric changes and histological alterations characterized by proliferative increases in the tissue layers. The opening angle, along with residual strain at the mucosal and serosal surface, increased in the remnant small intestine (P < 0.05). All changes increased as function of postoperative time and were most prominent in the remnant ileum. However, the stress–strain relationship remained unchanged. In conclusion, this study demonstrated that resection of the majority of the small bowel results in significant remodelling in structural and residual strain properties in the remnant small intestine. The remodelling seems to be guided by the need for a greater absorptive surface area rather than for a change in the stress–strain properties.
Video‐based spatio‐temporal maps for analysis of gastric motility in vitro: effects of vagal stimulation in guinea‐pigs
Authors: Berthoud H‐R. , Hennig G. , Campbell M. , Volaufova J. , Costa M.
Published: March 2003

Abstract Our aim was to evaluate topographically specific gastric motility changes induced by graded vagal activation. A recently developed method of constructing spatio‐temporal maps of motility from video movies was adapted to the in vitro perfused guinea‐pig stomach with an intact vagal nerve supply. In the unstimulated preparation, spontaneous activity was low or absent. Bilateral vagal stimulation with frequencies as low as 0.2 Hz triggered weak anally, and in some cases orally, propagating antral contractions at rates of about 5–6 min−1. Upon stimulation with higher frequencies, antral contractions increased significantly in length (starting more proximally) and amplitude, and produced large pressure peaks of up to 25 hPa, with maximal effects at 2–4 Hz. In contrast, the speed of propagation and the interval between peristaltic waves did not change with vagal stimulation at any frequency. Vagal stimulation also produced a significant and frequency‐dependent enlargement of the fundus with a maximal effect at 4 Hz. It is concluded that a very low tonic vagal activity is apparently necessary and sufficient to express basic antral motility, while more sustained vagal activity is necessary for high‐amplitude gastric contractions and significant sustained fundic relaxation. The constant interval between propagating contractions supports the concept that vagal input impinges on intrinsic enteric neural circuits that have a modulatory role in the myogenic mechanism underlying slow‐wave peristalsis, rather than directly on gastric musculature.
Cholecystokinin octapeptide increases rectal sensitivity to pain in healthy subjects
Authors: Sabaté J‐M. , Gorbatchef C. , Flourié B. , Jian R. , Coffin B.
Published: March 2003

Abstract  Hypersensitivity during rectal distension has been demonstrated in irritable bowel syndrome (IBS). Studies performed in animals and indirect data in humans suggest that cholecystokinin (CCK) could modulate visceral sensations. The aim of this study was to assess the effects of i.v. infused sulphated cholecystokinin octapeptide (CCK‐OP) on rectal sensitivity in response to distension. In eight healthy subjects, rectal sensitivity and compliance were determined during a randomized double‐blind study, with four sessions each separated by 7 days. Sensory thresholds and rectal compliance were assessed during slow‐ramp (40 mL min−1) and rapid‐phasic distensions (40 mL s−1, 5 mmHg stepwise, 1‐min duration), and were compared before and during continuous infusion of either saline or CCK‐OP at 5, or 20 or 40 ng kg−1 h−1. During rapid phasic distension but not during slow ramp distension, CCK‐OP at 40 ng kg−1 h−1 produced a significant decrease in sensory thresholds compared with the basal period. Rectal compliance was not modified by any infusion. At pharmacological doses, CCK‐OP decreases sensory thresholds during rapid phasic distension that may preferentially stimulate serosal mechanoreceptors, but has no effect on mucosal mechanoreceptors stimulated during slow ramp distensions. Modulation of rectal sensitivity by CCK could be implicated in the pathogenesis of the rectal hypersensitivity observed in IBS.
Simplified neuropathological diagnosis of dementia with Lewy bodies
Authors: Harding  , Halliday
Published: March 2003

Pathological criteria have recently been developed to differentiate those cases where Lewy bodies contribute to the dementing process. We applied consensus criteria to 20 cases with a pathological diagnosis of Alzheimer’s disease (all demented) and/or Parkinson’s disease (three without dementia) and eight controls. In addition, we applied the criteria to the different cortical layers to determine whether the site of the semiquantification affected the diagnosis. In the parietal lobe, few Lewy bodies were observed, and this region could be excluded. Rare Lewy bodies present in the frontal association cortex in a number of Parkinson’s disease cases resulted in their classification as limbic or transitional cases with Lewy bodies. Exclusion of this non‐limbic association cortex resulted in many of these cases with rare cortical Lewy bodies being re‐classified as having brain stem predominant Lewy bodies, thus improving the diagnostic accuracy of the criteria. Most of these cases were non‐demented. No other case was re‐classified by excluding these cortical regions from the analysis. Few Lewy bodies were present in cortical layers I and II, and these layers could be excluded from the semiquantitative procedure without change to the overall classification of cases. The occasional presence of possible Lewy bodies in cases with Alzheimer’s disease and controls incorrectly classified these cases as having brain stem predominant Lewy body disease, although these cases had no brain stem Lewy bodies. These modifications to the consensus criteria for assessing Lewy body disease (i.e. exclude parietal and frontal lobe, cortical layers I and II, and cases without brain stem Lewy bodies), provide significant time and cost savings for neuropathologists and researchers using this criteria to diagnose and study dementia with Lewy bodies.
Cell death mechanisms in the olfactory bulb of rats infected intranasally with Semliki Forest virus
Authors: Sammin  , Butler  , Atkins  , Sheahan
Published: March 2003

Semliki Forest virus (SFV) infection of mice is used as a model to study pathogenic processes occurring in viral encephalitis. It has previously been shown that avirulent strains of SFV differ from virulent strains in showing restricted multiplication in neurones and in producing localized rather than widespread lesions in the central nervous system (CNS). Restricted neuronal damage is age‐dependent and does not occur in neonatal animals. In this study, cell death mechanisms occurring in the CNS of adult rats infected intranasally (i.n.) with a virulent (SFV4) and an avirulent (A7) strain of SFV have been investigated. Although i.n. infection of rats was less efficient than that of mice, SFV4 reached a higher titre in the CNS of infected animals than A7. Neuronal destruction and leucocytic infiltration occurred throughout the forebrain of SFV4‐infected rats. A7‐infected rats remained clinically normal although degenerate neurons and inflammatory changes were present primarily in the olfactory system. Following infection with either A7‐SFV or SFV4, TUNEL‐positive nuclei were seen in areas of leucocytic infiltration and among the poorly differentiated cells of the rostral migratory stream. Migrating cells had condensed nuclear chromatin, compacted cytoplasm and intact cellular membranes, characteristic of apoptosis, and were sparsely immunolabelled for viral antigen. In SFV4‐infected rats, large numbers of contiguous neurones in forebrain areas exhibited cytoplasmic eosinophilia and karyolysis and were surrounded by phagocytic cells. Such neurones contained dense intracytoplasmic deposits of viral antigen and showed weak cytoplasmic TUNEL staining; electron microscopy showed membrane disruption, organelle disintegration, irregular chromatin condensation and cytoplasmic aggregation of virus particles. Bcl‐2 staining was similar in infected and control rats and was most intense in randomly distributed Purkinje cells in the cerebellum; neurons in the olfactory bulbs were unstained. These findings indicate that during SFV encephalitis, infiltrating leucocytes and neural precursor cells undergo apoptosis whilst productively infected neurons undergo necrosis.
CD44 expression in primary and recurrent oligodendrogliomas and in adjacent gliotic brain tissue
Authors: Hagel  , Stavrou
Published: March 2003

CD44 expression was evaluated in 114 primary and recurrent oligodendrogliomas (46 primary oligodendrogliomas grade II and 15 recurrences grade II; 17 primary anaplastic oligodendrogliomas and nine recurrent oligodendrogliomas grade III; 14 glioblastomas with oligodendroglial growth pattern and 13 tumour recurrences grade IV). CD44 expression was found to correlate with tumour grading (P<0.001) and with survival (Kaplan–Meier Log Rank P<0.01, median survival 28 months in oligodendrogliomas with CD44 expression vs. 108 months in CD44‐negative tumours). However, multivariate Cox regression analysis of grading and CD44 expression revealed that CD44 expression had no prognostic relevance independent of histological grading. Characterization of CD44 positive cells by double labelling with GFAP revealed that in addition to oligodendroglioma cells, reactive astrocytes within the tumour, at the invasive margin and along the pathways of oligodendroglioma invasion in the subpial matrix, and in the vicinity of vessels, frequently expressed CD44. It is suggested that in analogy to carcinoma invasion where a tumour‐induced production of hyaluronan was found in fibroblasts at the invasive margin of the tumour, in the brain reactive astrocytes may produce hyaluronan which would facilitate the adhesion of new CD44‐positive astrocytic processes but which would also promote tumour invasion.
Expression of Bcl‐2 and Bax in oligodendrogliomas and their relationship to apoptosis
Authors: Delgado  , Anderson  , Whittle  , Wharton
Published: March 2003

Apoptotic bodies are frequently found in oligodendrogliomas, particularly in the anaplastic subtype. A range of proteins, such as those of the Bcl family, are implicated in the control of apoptosis. The ratio of antagonists of apoptosis, such as Bcl‐2, to agonists, such as Bax, is thought to determine the outcome for a particular cell. This study aimed to determine the expression of Bcl‐2 and Bax proteins in a series of oligodendrogliomas and to relate the expression of these to measures of apoptosis. Immunohistochemistry was used to detect the expression of Bcl‐2 and Bax in an archival series of 32 oligodendrogliomas. The results were scored semiquantitatively for the extent and intensity of tumour staining. Apoptosis indices were determined by counting apoptotic bodies on haematoxylin and eosin staining and the percentage of cells showing a positive reaction with the TdT‐mediated dUTP‐biotin nick end‐labelling technique (TUNEL). Granular cytoplasmic staining for Bcl‐2 was seen in tumour cells in 81% of cases. Cases with a strong intensity (but not extent) of staining showed a lower TUNEL index (P=0.038). Bcl‐2 expression was identified in the walls of intratumoural blood vessels in 55% of cases and in peri‐tumoural neurones (where present) in 87%. Bax expression was detected in tumour cells in 69% of cases but no relationship to TI was detected. Bax positivity was seen in blood vessels in 44% of cases and peri‐tumoural neurones in 60%. Bcl‐2 and Bax were concluded to be expressed in a high proportion of oligodendrogliomas, suggesting that they may exert a regulatory role in cell death in these tumours.
Distinct phases of cryogenic tissue damage in the cerebral cortex of wild‐type and c‐fos deficient mice
Authors: Steinbach  , Weissenberger  , Aguzzi
Published: March 2003

To characterize the development of tissue damage following cryogenic injury to the mouse cortex, the time course of histopathological changes, transcriptional responses and DNA strand breaks following application of a liquid nitrogen‐cooled probe to the surface of the parietal bone were assessed. Distinct phases of tissue damage were observed: after 30 min, there was demarcation of a core lesion followed by mainly necrotic cell death starting 2 h after injury. At 12 hours, progressive apoptotic death of scattered cells in the periphery of the core lesion was detected, resembling the penumbra observed in ischaemic stroke. In situ hybridization for c‐fos revealed an absence of expression in the core region, suggesting early cessation of transcription. There was strong induction of c‐fos in the penumbra 30 min after the lesion, which had spread over the ipsilateral hemisphere at 2 h, possibly caused by peri‐infarction depolarization. At later time points, sustained expression of c‐fos was observed in some cells in the penumbra. Since a role for c‐fos has been postulated in the initiation or execution of apoptotic pathways, the susceptibility of c‐fos deficient mice was explored (n=4) in this model. Cryoinjury‐induced tissue injury was markedly attenuated in c‐fos deficient mice. A model of the phases and mechanisms of cryogenic injury is proposed, which discriminates an early phase characterized by physical changes caused by hypothermia and their immediate consequences (i.e. transcriptional block), an intermediate phase where secondary changes lead to necrosis in the core region, and a final phase of delayed apoptotic cell death in the penumbra.
Cryopreservation of viable human glioblastoma xenografts
Authors: Goike H. M. , Asplund A. C. , Pettersson E. H. , Liu L. , Ichimura K. , Collins V. P.
Published: March 2003

Human tumour xenografts maintained in nude mice are a valuable research tool. The passaging and maintenance of human tumour xenografts in immune‐deficient animals are expensive and labour‐intensive. This study presents a protocol that permits long‐term cryopreservation of viable glioblastoma xenograft tissue pieces in liquid nitrogen. Twenty different human glioblastoma xenografts that have been successfully transplanted and repeatedly passaged in nude mice were cryopreserved to validate the method. Different passages were cryopreserved for up to 40 months. On retransplantation of the tumours, all cases except one grew successfully. In order to ensure that the individual tumours did grow (not induced mouse tumours) restriction fragment length polymorphism analysis with variable number of tandem repeats (VNTR) probes was carried out. The method permits the long‐term storage of viable, retransplantable glioblastoma xenografts. It minimizes animal use for the maintenance of xenografts and permits cryo‐back‐up of valuable tumours, thus markedly reducing the cost and increasing the accessibility of human tumour xenografts as a research tool in biology and genetics.
Apoptosis of astrocytes with enhanced lysosomal activity and oligodendrocytes in white matter lesions in Alzheimer's disease
Authors: Kobayashi K. , Hayashi M. , Nakano H. , Fukutani Y. , Sasaki K. , Shimazaki M. , Koshino Y.
Published: March 2003

Cerebral white matter lesions in Alzheimer's disease (AD) consist of subcortical degeneration and ischaemic–hypoxic changes. Glial changes are intimately associated with the white matter lesions, and regressive changes in astrocytes and loss of oligodendroglial cells have been reported. We quantitatively compared glial changes including apoptosis and enhanced lysosomal activity in the frontal and temporal white matter by using terminal dUTP nick end labelling (TUNEL) and immunohistochemistry for glial markers, lysosomes and apoptosis‐regulating proteins in non‐familial AD brains. The degree of myelin pallor and axonal loss varied considerably in both the frontal and temporal white matter but fibrillary gliosis in demyelinated lesions tended to be less prominent in the temporal white matter in AD cases. A morphometric study with planimetric methods for cross‐sectional areas of frontal and temporal white matter revealed that the white matter of AD cases manifested atrophy with significant reduction in frontal (11.9%) and temporal (29.4%) white matter compared to normal controls. Double immunolabelling for glial fibrillary acidic protein (GFAP) and KP1 (CD68) revealed KP1‐positive fragmented structures within the weakly GFAP‐labelled astrocytes. These KP1‐positive structures correspond to process fragmentation and cytoplasmic vacuoles, which in turn indicate enhanced lysosomal activity during regressive changes in astrocytes. The KP1‐modified astrocytes were not found in Pick's disease and corticobasal degeneration. The density of apoptotic glial cells, largely oligodendroglial, was significantly higher in the temporal than in the frontal white matter, and most GFAP‐positive astrocytes with regressive changes were apoptotic. GFAP‐positive astrocyte density was statistically the same in the frontal and temporal white matter, but the density of KP1‐modified astrocytes was higher in the temporal than in the frontal white matter. The rate of white matter shrinkage was significantly correlated with the density of apoptotic glial cells and the density of KP1‐modified astrocytes in the temporal lobe in AD cases. An increase in apoptotic glial cell density was found to contribute to GFAP‐positive astrocytes with regressive changes in temporal white matter, while apoptosis of vascular smooth muscle cells did not show topographical accentuation. Astrocytes labelled with beta amyloid protein were not apoptotic, and the density of apoptotic cells labelled with CD95 and caspase‐3 was too low in both types of white matter to be statistically evaluated. Our results imply that regressive changes in astrocytes and glial apoptosis are, to some extent, associated with white matter lesions, particularly of the temporal lobe in AD brains. The presence of apoptotic astrocytes with evidence of regressive change could therefore be a histological hallmark for white matter degeneration in AD.
The neuropathology and pathogenesis of systemic lupus erythematosus
Authors: Scolding N. J. , Joseph F. G.
Published: March 2003

Systemic lupus erythematosus (SLE) is a chronic, multisystem, autoimmune disease in which neuropsychiatric involvement occurs in about 50% of patients and carries a poor prognosis. Despite extensive research, the precise mechanisms of nervous tissue injury remain the least well understood. This article summarizes the important clinical neuropsychiatric features of SLE and, reviewing classical histopathological and more recent experimental studies, discusses theories concerning their presumed pathogenesis. The distinctive production of diverse autoantibodies seems to be related to defective clearance of apoptotic cells. Antibody‐mediated neural cell injury and rheological disturbances represent the two principal suggested mechanisms of tissue injury. An interplay between these processes, underlying genetic factors, their modification by hormones, complicated by a number of secondary factors, may explain the wide spectrum of features encountered in this disease.
Structured review of neonatal deaths in a managed care organisation
Authors: Escobar  , Yanover  , Gardner  , Golembeski  , Armstrong  , Shum  , Kipnis
Published: March 2003

We sought to quantify neonatal mortality (< 28 days) in a 10‐hospital system, determine what proportion was associated with suboptimal neonatal care and make recommendations on how neonatal mortality rates (NMRs) could be used in quality improvement efforts. Deaths were identified using electronic linkage to the State of California Death Certificate Tapes. Individual fatalities were reviewed by a minimum of two physicians who did not care for the infant. Deaths were classified as either being associated with suboptimal care or not. For deaths where suboptimal care was an issue, emphasis was on delineating the process involved in the death. Subjects were all neonatal deaths among 64 469 babies born in 1990–91 in the 10 birth facilities of the Kaiser Permanente Medical Care Program, Northern California Region. A total of 241 neonatal deaths were identified. Adjusting for prematurity by increasing the follow‐up period in preterm babies (included as neonatal deaths if they died up to 40 weeks corrected gestational age + 27.9 days) increased overall mortality rates by 5%. Birthweight‐specific NMRs in Kaiser Permanente are similar to those of other published reports. Among the 198 deaths in babies weighing  500 g at birth, only 14 (7%) were possibly associated with suboptimal care. In populations with access to health insurance, reporting only aggregate NMRs is of limited use. The number of deaths that could be ascribed to suboptimal neonatal care is very small and measuring variations in rates of such deaths is difficult. Future measurements of quality of care will require more sophisticated measures, database systems, review strategies and dissemination methods.
Ascaris–Trichuris association and malnutrition in Brazilian children
Authors: Saldiva  , Silveira  , Philippi  , Torres  , Mangini  , De Souza Dias  , Da Silva  , Buratini  , Massad
Published: March 2003

This work was designed to evaluate the role of intestinal parasites on nutritional status in three rural areas of Brazil. A total of 520 children aged 1–12 years were studied through a questionnaire concerning housing, socio‐economic conditions and a 24‐h food intake recall. Measurements of weight and height were also performed, and three stool samples were collected on consecutive days for parasitological analysis. Scores of the standard deviation (z‐scores) for the weight‐for‐height and height‐for‐age were used to characterise the growth profile. A high prevalence of intestinal parasites was detected, with Giardia lamblia (44%), Endolimax nana (43%), Ascaris lumbricoides (41%) and Trichuris trichiura (40%) being the most prevalent. Eleven per cent of the children were classified as showing stunting. Inadequate daily caloric intake was observed in 78% of the population and the proportion of those with inadequate protein intake was 34%. Logistic regression analysis was employed for the multivariate study. Stunting was significantly associated with estimators of low economic income, inadequate protein intake and polyparasitism, especially the association between Ascaris lumbricoides and Trichuris trichiura.
The association of birth interval, maternal age and season of birth with the fertility of daughters: a retrospective cohort study based on family reconstitutions from nineteenth and early twentieth century Quebec
Authors: Smits  , Zielhuis  , Jongbloet  , Bouchard
Published: March 2003

In a historical follow‐up study, we evaluated the association of the fertility of daughters with five perinatal factors: short (< 15 months) or long ( 45 months) preceding birth interval, low ( 20 years) or advanced ( 40 years) maternal age and season of birth. We used data concerning 2062 women married before the age of 31 and born in the Saguenay region of Quebec, Canada, between 1850 and 1899. Time between the wedding and first birth was used for the estimation of differences in fertility. Using logistic regression and controlling for several potential confounders, we found a slightly increased risk of monthly failure of conception for daughters born after a short but not for those born after a long birth interval (odds ratios [ORs] 1.09 [0.89, 1.33] and 0.87 [0.65, 1.16], respectively, with intervals between 21 and 32 months as the reference category). A slightly increased risk of conceptive failure was also seen for daughters of younger and older mothers (ORs 1.08 [0.89, 1.30] and 1.11 [0.91, 1.35], respectively, compared with maternal age between 24 and 30 years as the reference category). Fertility varied by season of birth (P = 0.02), with summer‐born daughters having lowest and winter‐born daughters having highest fertility. These results are consistent with the idea that maternal factors before or around birth play a role in the aetiology of reduced fertility. The data, however, do not unequivocally support the hypothesis that gave rise to the present study, namely that ovarian development may be disturbed after conception in conditions with an increased risk of maternal menstrual cycle irregularities.
From our own correspondent
Authors: Silverman William A.
Published: March 2003

Secrecy and rainmaking in medical research

There is a culture shift under way. The universities’ central product – knowledge – used to be regarded as a ‘common good,’ but it is in the process of being reappraised as ‘intellectual property’ . . . which must be walled off. This balkanization of knowledge, packaged for sale, will alter our universities and weaken them.

Nobel laureate John C. Polanyi1
What explains away the increased risk of histological chorioamnionitis in African‐American mothers of very‐low‐birthweight infants?
Authors: Dammann Olaf , Leviton Alan , Allred Elizabeth N.
Published: March 2003

We sought explanations for African‐American mothers’ increased risk of chorioamnionitis by sequentially adjusting for confounder variables both individually and in groups. We searched for a subset of covariates that had the most influence on the chorioamnionitis odds ratio (OR) of these women. The sample consisted of 305 African‐American and 520 White mothers who gave birth to a very‐low‐birthweight ( 1500 g) infant between 1991 and 1993, whose placenta was examined according to protocol and whose hospital chart was reviewed. Histologically proven chorioamnionitis was present in 43% of the placentas from African‐American women and in 27% of those from Whites (crude OR 2.1, 95% confidence interval 1.5, 2.8). Singleton status appeared to be the most important effect modifier, with significant crude ORs of 1.5 among singletons and 3.4 among non‐singletons. Using logistic regression models in the whole sample and in subgroups, we sought to ‘explain away’ this increased risk. Indeed, addition of information about confounder variables resulted in considerable reduction in the ORs to 1.1 among singletons and 1.9 among non‐singletons. Particularly important among the confounders were singleton birth, Medicaid insurance, duration of ruptured membranes and gestational age. We discuss the possibility that this set of confounding variables conveys, in part, the same information as the variable African‐American, and also perhaps information about the availability and/or utilisation of prenatal health care.
Incidence of childhood cancer in Ho Chi Minh City, Vietnam, 1995–97
Authors: Quoc N.M. , Hung N.C. , Kramárová E. , Parkin D.M.
Published: March 2003

Incidence rates of childhood cancer for the city of Ho Chi Minh are presented for the first time. For the 3‐year period 1995–97, a total of 302 cancer cases were registered in children under 15 years of age, with a male to female ratio of 1.1. The overall crude rate was 78.8 and the age‐standardised incidence rate was 88.4 per million person–years, which was low in comparison with other countries in eastern Asia and with the predominantly white population of Australia. Leukaemia (principally acute lymphocytic), brain tumours and lymphomas were the most common childhood neoplasms, which is consistent with the pattern observed in other registries of the region. The rate of retinoblastoma was higher than in the other regional registries. On the other hand, no cases of hepatocellular carcinoma were registered.
Preterm labour and delivery: a genetic predisposition
Authors: Dizon‐Townson Donna S.
Published: March 2003

Preterm delivery (PTD) complicates as many as 10% of pregnancies in the United States. Moreover, prematurity accounts for more than 70% of the consequent neonatal and infantile morbidity and mortality. Serious long‐term complications include cerebral palsy, respiratory disease, blindness and deafness. Despite substantial basic scientific, translational and clinical investigation in recent years, the PTD rate (10%) and the low birthweight rate (7%) remain largely unchanged. Indeed, the very aetiology and pathophysiology of PTD remain unknown in most cases. In short, PTD continues to constitute a major clinical and public health challenge of the highest order, a circumstance further compounded by the controversy surrounding the efficacy of current therapeutic regimens. In an effort to address the relevant knowledge gap, we put forth the hypothesis that PTD results, at least in part, from a genetic predisposition. Evidence supporting the hypothesis that certain women have a genetic predisposition to deliver preterm is growing. Moreover, the discovery of a gene mutation predisposing to PTD would constitute a major breakthrough for future research into the biology, prediction, and therapy of preterm labour. Presented here is a discussion of the evidence to support a genetic predisposition to PTD, molecular techniques proposed to study the genetics of preterm labour, and plausible candidate genes that warrant further investigation.
Perinatal mortality in twins and factors influencing mortality in Japan, 1980–98
Authors: Imaizumi Yoko
Published: March 2003

The perinatal mortality rate (PMR) in twins was analysed using Japanese vital statistics during the period 1980–98. There was a total of 1992 twin perinatal deaths. The PMR in twins significantly decreased from 91 per 1000 births in 1980 to 31 per 1000 in 1998. The PMR was higher in males than females, but the differences between the sexes decreased over time. It was significantly higher in the second‐born than the first‐born of the twins. The fetal death rate was 2.8 times higher in monozygotic than dizygotic twins. The PMR decreased to one‐sixth for the maternal age group ≥40 years, one‐fifth for <20 years, and between one‐third and a half for 20–39 years during the period 1980–98. It was lowest for birthweights (BW) between 2500 g and 2999 g during the entire period; the PMR decreased with gestational age (GA) up to 38–39 weeks and increased thereafter. The effect of BW on the PMR was greater than that of GA except in the shorter GA group. The proportion of twin perinatal deaths with extremely low BW (<1000 g) increased from 50% in 1980 to 68% in 1998. Thus, the declining PMR was unlikely to be due to the improvement in BW in twins. It is likely that it is related to the improved medical management of twins during the perinatal period and the first week of life.
Families with a perinatal death: is there an association between the loss and the birthweight of surviving siblings?
Authors: Melve Kari Klungsøyr , Skjærven Rolv , Øyen Nina
Published: March 2003

Our objective was to study birthweight among surviving siblings in families with and without a perinatal loss, and to evaluate whether different causes of death were associated with the results. Data were for 1967–98 from the Norwegian Medical Birth Registry. Births were organised with the mother as the observation unit through the personal identification number, providing sibship files. We analysed 550 930 sibships with at least two singletons, 208 586 sibships with at least three singletons and 45 675 sibships with at least four singleton births. We compared mean birthweight and gestational age between infants in sibships with and without a perinatal loss, total losses and the different causes of death. Surviving siblings in families with a perinatal loss had significantly lower mean birthweights than their counterparts in unaffected families, after adjusting for gestational age, interpregnancy interval, time period and marital status. An exception was found when cause of death was a birth defect, when growth retardation among surviving siblings was not found on average. We conclude that families who have lost an infant because of a birth defect do not appear to have an increased risk of adverse birth outcome associated with growth restriction.