bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oligomeric collagen XVIII‐derived endostatin requires cell surface heparan sulfate in order to induce morphological changes in endothelial and epithelial cell lines in vitro
Authors: Clamp A.R. , Blackhall F.H. , Henrioud A. , Jayson G.C. , Javaherian K. , Esko J. , Gallagher J.T. , Merry C.L.R 
Published: August 2004

Introduction  Monomeric endostatin (HEM) has been extensively investigated as an endogenous anti‐angiogenic molecule. In contrast, oligomeric endostatin (HED) induces a promigratory phenotype in endothelial cells in vitro that can be inhibited by an EM in a putative negative feedback loop (Kuo et al. 2001). Endostatin is heparin‐binding but the role of cell‐surface glycosaminoglycans (GAG) in regulating the activity of HEM/HED is unclear.Methods and results  Bovine aortic endothelial (BAE) cells plated onto a Matrigel substratum spontaneously form capillary‐like tubules. Addition of 50 nm HED, 16 h after plating induces the migration of BAE cells away from these tubules. This pro‐migratory action can be inhibited by coincubation with HEM. We have demonstrated that exogenous GAGs can also inhibit the actions of HED. This property is size dependent, with heparin‐derived oligosaccharides containing more than 20 monosaccharide units being optimal inhibitors. HED (50 nm) was also shown to induce marked morphological changes in the Chinese hamster ovary (CHO) epithelial cell line plated in Matrigel, i.e. cell elongation, lamellipodia formation and intercellular bridging. This novel observation allowed us to address the role of cell surface GAGs in HED function using a panel of CHO mutants with defined defects in GAG biosynthesis. CHO 745 cells, which lack all cell surface sulfated GAGs, fail to respond to HED stimulation, while CHO pgsD cells, which specifically lack cell surface heparan sulfate (HS), displayed an attenuated phenotype on HED stimulation with less cell elongation/intercellular bridging. Notably, CHO pgsF17 cells, which lack 2‐O‐sulfation of HS, respond normally to HED indicating that HS 2‐O‐sulfate groups are not necessary for the bioactivity of HED.To investigate the endostatin–GAG interaction further, zero‐length cross‐linking was utilized. This indicated that multiple HEM subunits can simultaneously bind to a single oligosaccharide chain with up to 3 HEM molecules cross‐linking to a heparin dp22. HED cross‐linking experiments indicate that both endostatin subunits in this molecule may bind to the same oligosaccharide chain. These results suggest that one potential anti‐angiogenic mechanism of HEM is to block the GAG‐binding sites for HED.Discussion  Cell surface GAGs are absolutely necessary for the bioactivity of HED. HS is required for a wild‐type response, although 2‐O‐sulfation is not essential. The ability to use a panel of GAG‐mutant CHO cells provides a well‐understood system in which to investigate the role of HS in HEM : HED regulation.
Role of heparan sulfate in embryoid body formation
Authors: Drummond K.J , Yates E.A. , Murray P.A. , Turnbull J.E. 
Published: August 2004

Introduction  Embryoid bodies (Ebs) are layered, ordered aggregates of cells which form when murine embryonic stem (ES) cells are grown in suspension. Ebs are made up of primitive endoderm cells overlaying an epithelium of epiblast cells, separated by a basement membrane and surrounding a central cavity. The generation of Ebs from undifferentiated ES cells has been used as a model for early development. The process of EB formation has been shown to require signalling through fibroblast growth factor (FGF) receptor 2, implicating heparan sulfate (HS) which is a necessary coreceptor for the formation of a signalling complex.Heparan sulfate proteoglycans are found both on the surface of cells and in the extracellular matrix. Within the cells, a newly synthesized HS chain is partially modified by a family of enzymes, many of which have multiple isoforms with differing substrate preferences. These modifications include the addition of sulfate groups at up to four positions on each disaccharide unit. The pattern of modifications that a HS saccharide undergoes alters its structure, affecting the ability of the HS to bind and regulate different FGF‐FGF receptor combinations, and so regulate signalling outcomes.It is hypothesized that the complement of modification enzymes that a cell expresses determines the structure of the HS that the cell produces, thereby altering the signalling response of the cell to HS‐binding factors such as FGFs. In this way, an ES cell could alter its HS to allow signalling by, for example, a particular FGF, setting in motion a chain of intracellular events leading to differentiation.Materials and methods  Methods used in this study include tissue culture, RT‐PCR and immunocytochemistry.Results  We have found that undifferentiated ES cells express HS as observed by cell staining with anti‐HS antibodies. They also display particular expression patterns of the different HS modification enzyme isoforms as measured by RT‐PCR. Studies on alterations in HS synthesis and structure during the process of EB formation are underway. In addition, the effect of the addition of exogenous heparin (a highly sulfated analogue of HS) and HS saccharides with variant structures on EB formation is being investigated.Discussion  Alterations in the profile of modification enzymes expressed by ES cells as they differentiate may correlate with changes in the structure of the HS they make. These changes may allow the differentiating cells to control the way in which they respond to their environment.These studies will allow the dissection of the structural requirements for a functional role of HS in embryoid body formation and stem cell differentiation.
The use of SA‐β‐Gal to assess cell senescence in intervertebral disc cells
Authors: Evans E.H. , Kletsas D. , Urban J. , Menage J. , Roberts S. 
Published: August 2004

Introduction  The intervertebral disc is reported to age faster than other connective tissues with significant degenerative changes already seen in the second decade of life. In other tissues, senescent cells have an altered phenotype, often with a decreased synthetic ability and response to anabolic cytokines. They appear to contribute to age‐related pathologies such as the degeneration of articular cartilage in osteoarthritis. Little is known of cell senescence in the intervertebral disc. In this study, we have investigated the production of senescence‐associated‐ß‐galactosidase (SA‐ß‐Gal), a ‘biomarker’ of cell senescence, in intervertebral disc cells both in cultured populations in vitro, and in vivo, in pathological human discs.Material and methods  Intervertebral disc cells were extracted from coccygeal bovine discs and cultured for 3 months. Confluent cell preparations were stained for SA‐β‐Gal (Fenton et al. 2001) at passages 0, 1, 2, 3 and 4. Preparations were fixed in 3% paraformaldehyde in phosphate‐buffered saline (PBS) for 5 min at room temperature and incubated for 24 h at 37 °C in SA‐ß‐Gal solution containing 1 mg/ml 5‐bromo‐4‐chloro‐3‐indolyl ß‐d‐galactopyranoside (X‐Gal, Sigma, Poole, UK), 5 mmol/l potassium ferrocyanide, 5 mmol/l potassium ferricyanide, 150 mmol/l NaCl, 2 mmol/l MgCl2 and 40 mmol/l trisodium citrate, titrated with NaH2PO4 to pH 6.0. Lysosomal (nonsenescent) ß‐galactosidase activity was detected using the same solution but titrated to pH 4.0. After staining, preparations were rinsed in ice‐cold PBS, dehydrated and mounted. Pathological human disc from patients with disc herniations or discogenic back pain were also stained for SA‐β‐Gal (immersing the tissue in the stain solution overnight) then cryosectioning (10 µm thick) and fixing. Articular cartilage was studied for comparison (Price et al. 2002).Results  Cultured intervertebral discs demonstrated some staining for SA‐ß‐Gal at all passages investigated, but there was little change in staining with passage number. Cells in most pathological human discs demonstrated staining for SA‐ß‐Gal. Positive cells were seen more commonly in herniated discs [7/9 (78%); mean age: 46 ± 13] than in those removed from patients with discogenic back pain [2/6 (33%); mean age: 32 ± 5].Discussion  To our knowledge, this is the first study of cell senescence in intervertebral disc cells. The greatest level was seen in tissue from herniated discs where cell cluster formation and cell proliferation are common (but the mean age of the herniation group was slightly higher than the discogenic back pain group). However, for a tissue demonstrating such significant age‐related degenerative changes, there is surprisingly little expression of SA‐ß‐Gal in comparison with that found in other pathological cartilages. These preliminary data suggest that, unlike the situation in osteoarthritis, early cell senescence is not a major contributing factor in the pathogenesis of disc degeneration.
The effects of human intervertebral disc aggrecan on neuronal and endothelial cell growth
Authors: Johnson W.E.B. , Caterson B. , Eisenstein S.M. , Snow D.M. , Roberts S. 
Published: August 2004

Introduction  The development of ‘discogenic’ low back pain has been associated with increased nerve growth into degenerated intervertebral discs, particularly in neovascularized areas. A marked loss of proteoglycans, particularly from the disc's inner regions, is also a marked feature of the degenerative process. As proteoglycans from other tissues can have inhibitory effects on nerve growth, we have hypothesized that the alterations in proteoglycan content seen in disc degeneration may affect the growth of nerves and blood vessels into the disc. To test our hypothesis, we have established cell culture assays to determine the effects of human intervertebral disc aggrecan, which forms the major proteoglyan found in the disc, on neuronal and endothelial cell growth.Materials and methods  Aggrecan (A1D1 preparations) isolated from the outer (anulus fibrosus, AF) and inner (nucleus pulposus, NP) regions of human lumbar intervertebral discs was incorporated into culture substrata, using methods previously described (Snow et al. 1990). Chick dorsal root ganglia (DRG) and the cell line SH‐SY5Y were used as models of nerve growth. HMEC‐1 and Eahy‐926 cell lines were used as models of endothelial cell growth.Results  Human disc aggrecan inhibited SHSY‐5Y cell attachment, SHSY5Y neurite outgrowth and induced sensory DRG neurite growth cone turning in a concentration‐dependent manner. Sensory neurites emanating from DRG across permissive substrates (collagen/laminin) were repelled by high (1 mg/ml), but not low (0.01 mg/ml) concentrations of disc aggrecan and became aligned to the aggrecan border. Disc aggrecan similarly inhibited endothelial cell adhesion, cell spreading and migration. HMEC‐1 and Eahy926 cells migrated over collagen substrates (type I) until they encountered disc aggrecan, where they either stopped migrating or, more commonly, changed their direction of movement and aligned to the aggrecan border. In general, aggrecan isolated from the AF was more inhibitory than that isolated from the NP. The inhibitory effects were partially abrogated following enzymic deglycosylation of the aggrecan, or if aggrecan was added in solution (i.e. was nonsubstrate bound).Conclusions  This study provides evidence that disc aggrecan inhibits neuronal and endothelial growth and migration and therefore supports a hypothesis that a loss of aggrecan from degenerated discs predispose the tissue to vascular and neuronal invasion.
Intra‐abdominal hypertension and the abdominal compartment syndrome
Authors: Hunter J. D. , Damani Z. 
Published: August 2004

SummaryThe pressure within the abdominal cavity is normally little more than atmospheric pressure. However, even small increases in intra‐abdominal pressure can have adverse effects on renal function, cardiac output, hepatic blood flow, respiratory mechanics, splanchnic perfusion and intracranial pressure. Although intra‐abdominal pressure can be measured directly, this is invasive and bedside measurement of intra‐abdominal pressure is usually achieved via the urinary bladder. This cheap, easy approach has been shown to produce results that correlate closely with directly measured abdominal pressures. Significant increases in intra‐abdominal pressure are seen in a wide variety of conditions commonly encountered in the intensive care unit, such as ruptured aortic aneurysm, abdominal trauma and acute pancreatitis. Abdominal compartment syndrome describes the combination of increased intra‐abdominal pressure and end‐organ dysfunction. This syndrome has a high mortality, most deaths resulting from sepsis and multi‐organ failure. Detection of abdominal compartment syndrome requires close surveillance of intra‐abdominal pressure in patients thought to be at risk of developing intra‐abdominal hypertension. The only available treatment for established abdominal compartment syndrome is decompressive laparotomy. Prevention of abdominal compartment syndrome after laparotomy by adoption of an open abdomen approach may be preferable in the patient at significant risk of developing intra‐abdominal hypertension, but this has not been demonstrated in any large trials. Most surgeons prefer to adopt a ‘wait and see’ policy, only intervening when clinical deterioration is associated with a significant increase in intra‐abdominal pressure.
Antibiotic‐treated infections in intensive care patients in the UK
Authors: Cuthbertson B. H. , Thompson M. , Sherry A. , Wright M. M. , Bellingan G. J. ,   the Intensive Care Society
Published: August 2004

SummaryThe purpose of this audit was to study reasons for starting antibiotic therapy, duration of antibiotic treatment, reasons for changing antibiotics and the agreement between clinical suspicion and microbiological results in intensive care practice. We conducted a multicentre observational audit of 316 patients. Data on demographic details, site, treatment and nature of infection were collected. The median duration of antibiotic therapy was 7 days. Infections were community‐acquired in 160 patients (55%). Antibiotics were started on clinical suspicion of infection in 237 patients (75%). Pulmonary infections were the most common, representing 52% of all proven infections. Gram‐negative organisms were the most common cause of proven infections (n = 90 (50%)). The antibiotic spectrum was narrowed in light of microbiology results in 78 patients (43%) and changed due to antibiotic resistance in 38 patients (21%). We conclude that the mean duration of treatment contrasts with existing published guidelines, highlighting the need for further studies on duration and efficacy of treatment in intensive care.
Intracranial pressure measurement, induced hypothermia and barbiturate coma in meningitis associated with intractable raised intracranial pressure
Authors: Cuthbertson B. H. , Dickson R. , Mackenzie A. 
Published: August 2004

SummaryWe report the use of intracranial pressure monitoring, mild hypothermia and barbiturate coma in a patient with meningococcal meningitis complicated by raised intracranial pressure.
A partially blinded randomised controlled trial of patient‐maintained propofol sedation and operator controlled midazolam sedation in third molar extractions
Authors: Leitch J. A. , Anderson K. , Gambhir S. , Millar K. , Robb N. D. , McHugh S. , Kenny G. N. C. 
Published: August 2004

SummaryPatient‐maintained sedation using propofol has recently been shown to be effective for dental surgery. We compared this new technique to the established technique of operator administered midazolam. The two groups were compared before, during and after sedation. The two primary outcomes were time until discharge and oxygen saturation. Vital signs, anxiety and psychomotor skills were also compared. State anxiety was reduced to a greater extent in the propofol group (mean difference 10 (SD 4) mm; p = 0.010. Propofol patients recovered quicker (mean difference 7 (SD 1.4) min; p = 0.001). Propofol patients had a smaller reduction in arterial oxygen saturation (mean difference 0.8 (SD 0.3)%; p = 0.030), and a reduced increase in heart rate (mean difference 9 (SD 2) beats.min–1; p < 0.001). Both techniques were well tolerated and safe. Propofol sedation offered superior anxiolysis, quicker recovery, less amnesia and less depression of simple psychomotor function.
The effect of a mechanical glottis on peak expiratory flow rate and time to peak flow during a peak expiratory flow manoeuvre: A study in normal subjects and patients with motor neurone disease
Authors: Suleman M. , Abaza K. T. , Gornall C. , Kinnear W. J. M. , Wills J. S. , Mahajan R. P. 
Published: August 2004

SummaryWe have evaluated a mechanical glottis in healthy volunteers and in patients with bulbar motor neurone disease. In healthy volunteers, the mechanical glottis increased peak flow rate and decreased the time to peak flow during forced expiration, but cough produced even higher flow rates and shorter times to peak flow. In patients, the mechanical glottis increased peak flow rate and decreased the time to peak flow. The mechanical glottis also produced higher peak flow rates when compared to the cough manoeuvres, and the time to peak flow was also significantly shorter with the mechanical glottis. We have shown that the use of a mechanical glottis tends to convert the airflow profile of a peak expiratory flow manoeuvre into that of a cough in both healthy volunteers and patients with motor neurone disease. Its potential role as an aid to clearance of airway secretions in patients with impaired laryngeal function remains to be seen.
The effect of celecoxib on intrathecal morphine‐induced pruritus in patients undergoing Caesarean section
Authors: Lee L. H. Y. , Irwin M. G. , Lim J. , Wong C. K. 
Published: August 2004

SummaryPruritus associated with intrathecal opioid administration is particularly common in pregnancy. Nonsteroidal anti‐inflammatory drugs (NSAIDs) can reduce the severity of this pruritus but have undesirable side effects. The recent development of drugs that can specifically inhibit the cyclooxygenase 2 isoenzyme have become an attractive alternative. This study was designed to evaluate the efficacy of such a drug (celecoxib) in reducing intrathecal opioid‐induced pruritus in a randomised double‐blinded study of 60 women undergoing Caesarean section. All of them received spinal anaesthesia with 3 ml of 0.5% hyperbaric bupivacaine and 0.3 mg preservative‐free morphine. After delivery of the baby, they received either oral celecoxib 200 mg or placebo. Visual analogue scores for pain and pruritus were measured at 30 min, 2, 4, 8, and 24 h. There was no difference in the severity and onset of pain and pruritus between the two groups. Timing of administration, inadequate dosing and possible altered pharmacokinetics in pregnancy may explain the lack of efficacy.
Fluxes of N2O from farmed peat soils in Finland
Authors: Regina K. , Syväsalo E. , Hannukkala A. , Esala M. 
Published: August 2004

SummaryAgricultural peat soils are important sources of nitrous oxide (N2O). Emissions of N2O were measured from field plots of grass, barley, potatoes and fallow on a peat field in northern Finland during 2000–2002 and in southern Finland in 1999–2002. In the north the mean annual fluxes of N2O (with their standard errors) during 2 years were 4.0 (±1.2), 13 (±3.0) and 4.4 (±0.8) kg N ha−1 from the plots of grass, barley and fallow, respectively. In the north there were no significant thaw periods in the middle of winter. As a result, the thawing in the spring did not induce especially large N2O emissions. Emissions of N2O were larger in the south than in the north. In the southern peat field the mean annual fluxes during 3 years were 7.3 (±1.2), 15 (±2.6), 10 (±1.9) and 25 (±6.9) kg N2O‐N ha−1 for grass, barley, potato and fallow plots, respectively. Here, the largest single episodes of emission occurred during the spring thaw each year, following winter thaw events. An emission factor of 10.4 kg N2O‐N ha−1 year−1 for the N2O emission from the decomposition of the peat results from these data if the effect of fertilization according to the IPCC default emission factor is omitted. The direct effect of adding N as fertilizer on N2O emissions was of minor importance. On average, 52% of the annual N2O flux entered the atmosphere outside the cropping season (October–April) in the north and 55% in the south. The larger N2O fluxes from the peat soil in the south might be due to the more humified status of the peat, more rapid mineralization and weather with more cycles of freezing and thawing in the winter.
Thymocytes induced by antigen injection into the anterior chamber activate splenic CD8+ suppressor cells and enhance the antigen‐induced production of immunoglobulin G1 antibodies
Authors: Li Xingya , Wang Yafei , Urso David , O'Rourke James , Cone Robert E. 
Published: August 2004

SummaryInjection of antigen into the ocular anterior chamber (AC) of a mouse eye (an immunologically privileged site) induces the activation of immunoregulatory NK1.1+, CD4– CD8–, T‐cell receptor (TCR) αβ+ thymocytes. These thymocytes transfer the suppression of delayed‐type hypersensitivity (DTH) when injected into mice sensitized to the same antigen but do not effect the suppression of DTH. On the other hand, the immunized recipients of these transferred thymocytes produce splenic CD8+ T cells that effect the suppression of DTH. However, it is unclear whether the thymocytes transferred from the AC‐injected donor differentiate into and/or activate CD8+ T‐splenic suppressor cells. We therefore sought to determine the origin of splenic suppressor cells produced in the recipients of immunoregulatory thymocytes transferred from donors that receive an injection of antigen into the AC. CD45.1+ thymocytes from mice that received an AC injection of 2,4,6‐trinitrobenzene sulphonic acid (TNP)‐bovine serum albumin (BSA) were transferred to congenic CD45.2+ TNP‐BSA‐immune recipients. Spleen cells from the recipients were then sorted based on anti‐CD45.1 or ‐CD45.2 antibody binding and assayed for suppressor cells. This was done by the injection of separated spleen cells into the footpad of TNP‐BSA‐immunized mice, concurrent with the induction of footpad swelling (contact sensitivity) of the footpad elicited by an epicutaneous application of picryl chloride. The systemic distribution of antigen after the injection of antigen into the AC was demonstrated by the injection of fluorescein or 125I‐labelled TNP‐BSA into the AC. The results demonstrate that (i) splenic CD8+ T‐suppressor cells produced in the immunized recipients of immunoregulatory thymocytes are derived from the CD45.2 recipient of the CD45.1+ thymocytes; (ii) the induction of recipient splenic suppressor T cells by the transferred immunoregulatory thymocytes requires that the recipient be immunized to the same antigen as that used to induce immunoregulatory thymocytes; (iii) antigen is introduced to the thymus after an injection of antigen into the AC; (iv) although the transfer of the suppression of DTH by regulatory thymocytes was not dependent on interleukin‐4 (IL‐4), CD4+ NK1.1– regulatory thymocytes from AC‐injected donors enhanced the production of immunoglobulin G1 antibodies to TNP‐BSA by an IL‐4‐dependent mechanism. These observations suggest that the adult thymus plays an active role in the induction and maintenance of anterior chamber‐associated immune deviation as manifested by the generation of the suppression of cell‐mediated immunity to exogenous antigen and the antigen‐induced production of IgG1 antibodies.