USPIO-related T1 and T2 mapping MRI of cartilage in a rabbit model of blood-induced arthritis: a pilot study.

Ultrasmall paramagnetic iron oxide (USPIO)-enhanced MRI is promising for evaluating inflammation. The aims of this study were to investigate the effect of USPIO on cartilage T1 and T2 mapping, and to evaluate a proposed rapid vs. conventional T2 map method for imaging cartilage in a blood-induced arthritis model. Knees of nine arthritic (induction by intra-articular autologous blood injection) and six control rabbits were imaged over time (baseline, weeks 1, 5, 10) by 1.5 T MRI. All rabbits had USPIO (35-75 µmol Fe/kg)-enhanced MRI at each time point. T1 and T2 (conventional and rapid) maps and signal-to-noise ratios (SNR) were obtained pre- and post-USPIO administration. Cartilage biochemistry and histology were compared with MRI. Excellent correlations were noted between T1 map values and histologic scores at week 10 pre-USPIO (medial, r = 0.93, P = 0.0007; lateral, r = 0.87, P = 0.005) in the arthritic group, but not between T2 map and histology. Marginally and significant differences were observed between pre- and post-USPIO T2 values at weeks 5 (P = 0.06) and 10 (P = 0.02), but only with the administration of high USPIO doses in the arthritic group using the conventional method. No significant differences were noted between pre- and post-USPIO T1 values at any imaging time points. Cartilage T2 maps with short-TR and conventional protocols provided similar T2 values [(decreased trend)] (P > 0.05). Concomitant use of USPIO to T1 and T2 mapping of cartilage would not impair the identification of interval changes of T1 and T2 maps. Rapid T2 map provides similar results compared to conventional method, but its validation warrants further investigation.

Effect of corticosteroids on orthodontic tooth movement in a rabbit model.

INTRODUCTION: While there are a growing number of studies on the effects of medications on orthodontic tooth movement (OTM), only few studies have investigated the role of corticosteroids, despite their widespread use. The aim of the current study was to evaluate the effects of triamcinolone acetonide injection on OTM in a rabbit model. STUDY DESIGN: Sixteen one-month old rabbits were randomly divided into two groups: Eight rabbits had triamcinolone acetonide (1 mg/kg/day) administered IM daily for 21 days (test group) while the remaining eight rabbits received no drug (control group). The rabbits in both groups had a tube bonded to the upper central incisors and a stainless steel helical spring was inserted in tube slot to apply 50 cN distal force. After 3 weeks, the rabbits were sacrificed and the distance between mesial corners of incisors was measured The incisors are associated tissue was processed for histology and the apical and cervical area of the roots evaluated. An observer who was blind to the study groups evaluated the specimens. RESULTS: All appliance-treated incisors in test and control groups showed evidence of tooth movement. The distance between the incisors was significantly greater in the triamcinolone acetonide treated group compared to the control group (P < 0.001). Histological examination revealed an increased number of resorption lacunae and decreased number of cuboidal osteoblastic cells around the apical and cervical area of the Incisor roots in the test compared to the control group (P < 0.01). CONCLUSION: Treatment with triamcinolone acetonide is associated with increased tooth movement in rabbits via increased resorptive activity in the alveolar bone.

Zoledronate and pamidronate depress neutrophil functions and survival in mice.

BACKGROUND AND PURPOSE: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been identified as a severe complication of patients previously treated with i.v. bisphosphonates. It has been noted that necrotic bone from BRONJ sites display signs of bacterial infection suggesting that an immune defect may play a role in the pathophysiology of BRONJ. Here, we have examined the effect of two potent bisphosphonates, zoledronate and pamidronate, on neutrophil function, differentiation and survival. EXPERIMENTAL APPROACH: The effect of bisphosphonates on chemotaxis, NADPH oxidase activity and neutrophil survival were assessed in vitro using bone marrow-derived primary neutrophils or in vitro differentiated haematopoetic progenitors from mice. The same parameters and the number of circulating neutrophils were quantified in neutrophils isolated from mice treated in vivo with zoledronate. In vivo recruitment of neutrophils was assessed by sodium periodate-induced peritonitis. KEY RESULTS: Zoledronate and pamidronate inhibited in vitro neutrophil chemotaxis and NADPH oxidase activity in a dose-dependent manner. In vivo recruitment of neutrophils was also suppressed. Zoledronate did not affect in vitro differentiation of neutrophils but shortened their life span in a granulocyte-colony stimulating factor-dependent manner. fMLP-induced activation of RhoA activity was decreased by zoledronate treatment. CONCLUSIONS AND IMPLICATIONS: Our results show that bisphosphonate exposure leads to impaired neutrophil chemotaxis, neutrophil NADPH oxidase activity and reduced circulating neutrophil counts. This work suggests that bisphosphonates have the potential to depress the innate immune system for a prolonged time, possibly contributing to the pathogenesis of BRONJ.

A biomechanical model of agonist-initiated contraction in the asthmatic airway.

This paper presents a modelling framework in which the local stress environment of airway smooth muscle (ASM) cells may be predicted and cellular responses to local stress may be investigated. We consider an elastic axisymmetric model of a layer of connective tissue and circumferential ASM fibres embedded in parenchymal tissue and model the active contractile force generated by ASM via a stress acting along the fibres. A constitutive law is proposed that accounts for active and passive material properties as well as the proportion of muscle to connective tissue. The model predicts significantly different contractile responses depending on the proportion of muscle to connective tissue in the remodelled airway. We find that radial and hoop-stress distributions in remodelled muscle layers are highly heterogenous with distinct regions of compression and tension. Such patterns of stress are likely to have important implications, from a mechano-transduction perspective, on contractility, short-term cytoskeletal adaptation and long-term airway remodelling in asthma.

Herpes simplex virus type 2 and HIV infection among US military personnel: implications for health prevention programmes.

US military personnel are routinely screened for HIV infection. Herpes simplex virus type 2 (HSV-2) is a risk factor for HIV acquisition. To determine the association between HSV-2 and HIV, a matched case-control study was conducted among US Army and Air Force service members with incident HIV infections (cases) randomly matched with two HIV-uninfected service members (controls) between 2000 and 2004. HSV-2 prevalence was significantly higher among cases (30.3%, 138/456) than among controls (9.7%, 88/912, P < 0.001). HSV-2 was strongly associated with HIV in univariate (odds ratio [OR] = 4.2, 95% confidence interval [CI] = 3.1-5.8) and multiple analyses (adjusted [OR] = 3.9, 95% CI = 2.8-5.6). The population attributable risk percentage of HIV infection due to HSV-2 was 23%. Identifying HSV-2 infections may afford the opportunity to provide targeted behavioural interventions that could decrease the incidence of HIV infections in the US military population; further studies are needed.

Transcriptional response signature of human lymphoid cells to staphylococcal enterotoxin B.

Two shock-inducing toxins that result in similar eventual outcome of disease were studied to determine host gene expression responses, for correlation of both similar and unique gene patterns. We initially used differential display (DD)-PCR and identified 859 cDNA fragments that were differentially expressed after 16 h of in vitro exposure of human peripheral blood mononuclear cells (PBMC) to staphylococcal enterotoxin B (SEB). Upon further examination using custom cDNA microarrays and RT-PCR analysis, we found unique set of genes to each toxin (SEB or lipopolysaccharide (LPS)), especially at early time periods. By 16 h, there was a convergence of some gene expression responses and many of those genes code for proteins such as proteinases, transcription factors, vascular tone regulators, and respiratory distress. In an attempt to replicate the findings in vivo, monkeys were challenged with SEB and the resultant gene expression responses indicated a pattern typical of SEB exposure when compared to LPS, with a similar outcome. We provide evidence that vastly diverse global gene analysis techniques used in unison can not only effectively identify pathogen-specific genomic markers and provide a solid foundation to mechanistic insights but also explain some of the toxin-related symptoms through gene functions.

Effect of smoking and transdermal nicotine on colonic nicotinic acetylcholine receptors in ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is a disease largely of non-smokers, in which nicotine is of therapeutic value. The mode of action is unknown, but may involve nicotinic acetylcholine receptors (nAChRs) in the bowel wall. AIM: To investigate the presence of nAChRs in rectal mucosa, and the effect of smoking and nicotine on their expression. DESIGN: Prospective case-control study. METHODS: In situ hybridization (ISH) and immunocytochemistry (ICC) were used to show alpha3 nAChRs in colonic mucosa. Rectal mucosa was examined from controls (n=55) and patients with inactive UC (n=62), both smokers and non-smokers, by ICC, using two antibodies to show the density and distribution of receptors in the mucosa. Non-smokers with UC (n=43) were given transdermal nicotine or placebo patches for 6 months, and rectal biopsies, taken before and after treatment, were examined by ICC to show nAChRs. RESULTS: In normal colon, ISH and ICC showed alpha3 subunit in a wide variety of cells, including mucosal epithelium. In rectal biopsies, neither smoking nor nicotine influenced the expression of alpha3 immunoreactivity in epithelium, either in controls or UC. However, controls had a significantly greater density of immunodetectable mucosal epithelium alpha3 subunit, compared with UC patients. DISCUSSION: The presence of nAChRs in colonic epithelium may be pertinent to the beneficial effect of nicotine in UC, but since neither smoking nor nicotine treatment is associated with any change in the expression of epithelial alpha3 nAChRs, the effect may be due to functional changes in the receptor. The decreased number of alpha3 nAChRs in UC compared with controls may be related to an increased cell turnover in UC.

The ABC transporter genes of Plasmodium falciparum and drug resistance.

The seminal observations that (a) chloroquine-resistant Plasmodium falciparum strains accumulate less drug than more sensitive parasites, and (b) chloroquine resistance could be modulated in vitro by the classic multidrug-resistance (MDR) modulator verapamil, suggested not only that parasite resistance to multiple drugs may be similar to the MDR phenotype described in mammalian cancer cells, but that homologous proteins may be involved. These findings prompted search for MDR-like genes in the parasite. To date, three full-length ABC transporter genes have been isolated from P. falciparum: two P-glycoprotein-like homologues, pfmdr1 and pfmdr2, and a homologue of the yeast GCN20 gene, pfgcn20.

Mouse granulated metrial gland cell cytotoxicity of Wehi 164 cells: is there a role for interleukin-3 and tumour necrosis factor-alpha?

PROBLEM: Mouse granulated metrial gland (GMG) cells are maternal, cytotoxic cells found in the uterine wall in pregnancy. In vivo, they are cytotoxic to layer 1 labyrinthine placental cells. In an in vitro system, granulated metrial gland cells are highly cytotoxic to Wehi 164 fibrosarcoma cells. In this study the role of interleukin (IL)-3 and tumour necrosis factor (TNF)-alpha in granulated metrial gland cell cytotoxic activity was investigated. METHOD OF STUDY: Chromium-release cytotoxicity assays using mouse metrial gland effector cells and Wehi 164 target cells with the addition of IL-3 or an antibody to TNF-alpha. RESULTS: An antibody to TNF-alpha reduced the level of cytotoxic activity. IL-3 had no effect on the level of cytotoxicity. CONCLUSION: Mouse granulated metrial gland cells kill using a TNF-alpha mediated mechanism which is independent of IL-3 stimulation.

Effect of serum on mouse granulated metrial gland cell cytotoxicity.

PROBLEM: To examine factors affecting mouse granulated metrial gland cell cytotoxicity. METHOD OF STUDY: Chromium-release assays using mouse metrial gland cell suspensions targeted against Wehi 164 fibrosarcoma cells were used. Modulation of cellular cytotoxicity was investigated using an antibody, anti-asialo-GM1, to attempt depletion of effector cells and sera to determine if inhibitory factors are present in blood in vivo. RESULTS: No reduction in cellular cytotoxicity was found following treatment of effector cells with asialo-GM1 antibody, but there was a reduction following treatment with asialo-GM1 antibody plus guinea pig serum and with guinea pig serum alone. Sera from pregnant, male, and SCID mice also reduced the level of cytotoxicity by metrial gland cell suspensions. CONCLUSIONS: The reduction in cytotoxicity in the presence of serum indicates that there are factors in the blood which are inhibitory to granulated metrial gland cell cytotoxic activity in vivo. The resistance of mouse metrial gland cells to asialo-GM1 antibody depletion is supportive of a natural cytotoxic (NC) lineage for this cell type.

Natural cytotoxic and antibody-dependent cellular cytotoxic activity of cells in the decidua basales and metrial glands of pseudopregnant rats with deciduomata.

Cytotoxic cells are present in the uterine wall of pregnant rats. To determine if the cytotoxic activity arises in response to semen or the products of conception, the profile of cytotoxic activity in deciduomata of pseudopregnant rats was examined. To examine NK activity, Yac-1 cells were used as targets in chromium release cytotoxicity assays and an antibody to Yac-1 cells was included in some assays to determine antibody-dependent cellular cytotoxic (ADCC) activity. Cells from the metrial glands and deciduae of deciduomata of rats at days 10 and 13 of pseudopregnancy did not show NK activity but ADCC activity was present. To examine natural cytotoxic (NC) activity, Wehi 164 cells were used as targets in chromium release cytotoxicity assays. Cells isolated from the metrial glands and deciduae of rats at day 10 of pseudopregnancy were able to kill Wehi 164 cells after 21 h assays, thus demonstrating NC activity. The profile of cytotoxic activity in the uterine wall of pseudopregnant rats with deciduomata is similar to that found in pregnancy and is thus independent of semen or the products of conception.

An innovative problem-solving assessment for groups of first-year medical undergraduates--Think Tanks.

A problem-solving assessment has been devised and used for groups of first-year medical students at Southampton University. Five cohorts of approximately 160 students have taken the assessment since 1990. The assessment was part of a Locomotor system course that integrated biological and behavioural sciences and clinical specialties. The course also included lectures, practicals and tutorials and occupied the first 7 weeks of the last (10-week) term. Other assessments of the course involved essay writing and a spotter-type practical. For the problem-solving assessment, groups of about six students ('Think Tanks') received a problem which they had to investigate during the course. The students had some choice in the problem they were to study. The problems were designed, by staff, to cover aspects of movement in the context of health and disease. A staff advisor was assigned to each Think Tank group to provide general support. The results of the investigations of each Think Tank were displayed at the end of the course in the form of a poster aimed at informing their peers. Three members of staff gave each Think Tank group a communal oral examination and the performance of the group was given a grade. Each member of the group, normally, was allowed to add this grade to their marks for the whole year.

Episodic evolution mediates interspecies transfer of a murine coronavirus.

Molecular mechanisms permitting the establishment and dissemination of a virus within a newly adopted host species are poorly understood. Mouse hepatitis virus (MHV) strains (MHV-A59, MHV-JHM, and MHV-A59/MHV-JHM) were passaged in mixed cultures containing progressively increasing concentrations of nonpermissive Syrian baby hamster kidney (BHK) cells and decreasing concentrations of permissive murine DBT cells. From MHV-A59/MHV-JHM mixed infection, variant viruses (MHV-H1 and MHV-H2) which replicated efficiently in BHK cells were isolated. Under identical treatment conditions, the parental MHV-A59 or MHV-JHM strains failed to produce infectious virus or transcribe detectable levels of viral RNA or protein. The MHV-H isolates were polytrophic, replicating efficiently in normally nonpermissive Syrian hamster smooth muscle (DDT-1), Chinese hamster ovary (CHO), human adenocarcinoma (HRT), primate kidney (Vero), and murine 17Cl-1 cell lines. Little if any virus replication was detected in feline kidney (CRFK) and porcine testicular (ST) cell lines. The variant virus, MHV-H2, transcribed seven mRNAs equivalent in relative abundance and size to those synthesized by the parental virus strains. MHV-H2 was an RNA recombinant virus containing a crossover site in the S glycoprotein gene. At the molecular level, episodic evolution and positive Darwinian natural selection were apparent within the MHV-H2 S and HE glycoprotein genes. These findings differ from the hypothesis that neutral changes are the predominant feature of molecular evolution and argue that changing ecologies actuate episodic evolution in the MHV spike glycoprotein genes that govern interspecies transfer and spread into alternative hosts.

Biochemical analysis of the response in rat bone marrow cell cultures to mechanical stimulation.

Bone marrow cells obtained from rat femora were subjected to primary culture with 15% fetal bovine serum in the presence of 10(-8) M dexamethasone, and following trypsin treatment 5 days later were seeded on Petriperm dishes which have a flexible bottom. After a 2-day subculture, a cyclic stress consisting of a 1 s stretch (0.3% strain. 0.5 Hz) and a 1 s relaxation for 30 min every day was started. Culture tissue was removed on day 2 of the subculture (immediately prior to start of stimulation), and then on days 5 and 8 (3 and 6 days after the start of stimulation, respectively), at which times dry weight, DNA, alkaline phosphatase (ALP) activity, and bone Gla protein (BGP, osteocalcin) were measured. Both the dry weight and DNA showed a significant increase in the stimulated group by day 8, while the ALP activity showed a significant increase by day 5. The BGP began to increase in the stimulated group on day 5 in contrast to the control group in which it only increased on day 8. These results support the contention that mechanical stimulation promotes the differentiation of osteogenic cells and enhances bone formation. Since in this experimental model the acceleration of bone formation by mechanical stimulation can be reproduced in vitro, it is extremely useful for investigating the mechanisms underlying mechanical stimulation.

A study of natural cytotoxic (NC) activity in the metrial glands of rats and mice.

Cell suspensions prepared from the metrial glands of rats killed on days 10, 13 and 20 of pregnancy and mice killed on day 12 of pregnancy were assessed for their ability to kill natural cytotoxic cell target Wehi 164 cells in a 51chromium-release cytotoxicity assay. High cytotoxicity indices were found with metrial gland cell suspensions from rats killed on days 10 and 13 of pregnancy and from mice killed on day 12 of pregnancy. Cell suspensions from rats killed on day 20 of pregnancy, when there are relatively few of the granulated metrial gland cells which characterize the metrial gland, had little natural cytotoxic cell cytotoxic activity. Direct observation of mouse granulated metrial gland cells killing co-cultured Wehi 164 cells were made using time-lapse video recordings. The results indicate that granulated metrial gland cells are a type of natural cytotoxic cell.

Lectin histochemistry of rat placental tissues.

Lectin binding of rat trophoblast subpopulations was examined at days 10, 12 and 15 of gestation. Biotinylated lectins, specific for a range of carbohydrates, were applied to paraffin wax embedded tissues. At day 10 of pregnancy, a wide and similar range of lectins reacted with ectoplacental cone and giant cells: chorionic lamina was relatively unreactive except with wheat germ agglutinin. At days 12 and 15, the range of lectins reacting with the placental labyrinth was relatively restricted. Spongiotrophoblast at day 12 showed lectin reactivity similar to that of ectoplacental cone cells but at day 15 the reaction pattern indicated loss of N-acetylgalactosamine residues in the large, glycogen-rich cells. Trophoblastic giant cells also showed wide lectin reactivity: some reacted only with cytoplasmic components whilst others showed pericellular reactivity. Varying lectin reactivity of giant cells in different regions of the placenta suggests functional differences. There was reduced lectin reactivity of endovascular trophoblast at day 15, compared with day 12 of pregnancy, which may reflect altered invasive potential associated with loss of sialic acid and N-acetylgalactosamine residues. The pattern of lectin reactivity suggests that ectoplacental cells, as well as giving rise to giant cells, may also contribute to spongiotrophoblast and to endovascular trophoblast.

Lectin histochemistry of pregnant rat uterine tissues.

Glycoconjugate residues were examined in the rat uterus at days 10, 12 and 15 of pregnancy using 17 biotinylated lectins with specificities for a variety of carbohydrate moieties. A wide variety of glycoconjugate residues were detected in the cytoplasm of some antimesometrial and mesometrial decidual cells with lectins from Canavalia ensiformis (Con A), Lens culinaris (LcH) culinaris (LcH), Pisum sativum (PSA), Griffonia simplicifolia II (GS-II), Triticum vulgaris (WGA), Griffonia simplicifolia I (GS-I), Maclura pomifera (MPA) and Phaseolus vulgaris (PHA-E and PHA-L). Reactivity with some of these lectins was also pericellular and the glycoconjugate residues detected may be related to extracelluar matrix produced by decidual cells. Reactivity with PHA-E, demonstrating complex carbohydrates, was most intense in the mesometrial decidua closest to the trophoblastic giant cells and may demonstrate glycoconjugates involved in maintaining integrity at this maternotrophoblast interface. Lectins derived from Helix pomatia (HPA), Vicia villosa (VVA), Glycine max (SBA) and Arachis hypogaea (PNA) reacted only with occasional small cells in antimesometrial or mesometrial decidua, probably demonstrating alpha and/ or beta-linked N-acetylgalactosamine residues on lymphocytes or monocytes. The glycoprotein granules of granulated metrial gland (GMG) cells in the decidua basalis and the metrial gland reacted strongly with WGA, MPA and PHA-L demonstrating complex carbohydrates including sialic acid residues and tri/tetra-antennary, nonbisected N-linked glycans. GMG cell cytoplasm reacted diffusely with Con A, LcH, PSA, WGA, PHA-E and PHA-L. In some GMG cells reactivity with WGA was apparently localised to the Golgi region indicating involvement in granule formation. Pericellular reactivity of some GMG cells with WGA may relate to migratory activity. The lectin reactivity of fibroblast-like stromal cells in the material gland was similar to that of the extracellular matrix and it is likely that many matrix molecules are produced by the stromal cells. A range of lectins (Con A, LcH, PSA, GS-II GS-I and PHA-L) reacted with some blood vessels in the metrial gland at day 12 of pregnancy: this may indicate activation changes associated with the transendothelial passage of GMG cells at this stage. Lectins derived from Dolichos biflorus (DBA), Bauhinia purpurea (BPA), Lotus tetragonolobus (LTA) and Ulex europaeus-I (UEA-I) did not react with decidual and metrial gland regions. Lectin binding profile studies can provide further information on the events occurring in the uterus in pregnancy: investigations at the ultrastructural level are required to resolve further intra and extracellular changes.

Antibody-dependent cellular cytotoxic activity of cells in the rat metrial gland in pregnancy.

Antibody-dependent cellular cytotoxic (ADCC) activity of cells in rat metrial glands at days 13 and 20 of pregnancy has been examined. A 51chromium-release cytotoxicity assay was carried out using Yac-1 cells and P815 cells as targets in the presence of the corresponding, heat inactivated rat antibody or non-immune rat serum. No killing was observed when effector metrial gland cells and target cells were cultured in the presence of non-immune rat serum. In the presence of rat antibody to Yac-1 cells, or rat antibody to P815 cells, cells from the metrial glands of rats killed at day 13 of pregnancy demonstrated ADCC activity, but cells from the metrial glands of rats killed at day 20 of pregnancy showed no ADCC activity. Spleen and peritoneal exudate cells displayed ADCC activity. Immunohistological and immunocytological studies showed OX-6, OX-34, OX-35 and OX-42 positive cells were present at days 13 and 20 of pregnancy, in sections of metrial glands and in the cell suspensions prepared for the cytotoxicity assays. It is suggested that macrophages are the cells most likely to be responsible for the ADCC activity in the rat metrial gland.

Information wanted.

I am a paediatric nurse in general A&E. I am trying to write a philosophy of care specifically to paediatrics in A&E and would appreciate any information from general and paediatric A&E departments, or copies of any philosophies being used in these areas.