Compromised function of regulatory T cells in rheumatoid arthritis and reversal by anti-TNFalpha therapy

Regulatory T cells have been clearly implicated in the control of disease in murine models of autoimmunity. The paucity of data regarding the role of these lymphocytes in human autoimmune disease has prompted us to examine their function in patients with rheumatoid arthritis (RA). Regulatory (CD4⁺CD25⁺) T cells isolated from patients with active RA displayed an anergic phenotype upon stimulation with anti-CD3 and anti-CD28 antibodies, and suppressed the proliferation of effector T cells in vitro. However, they were unable to suppress proinflammatory cytokine secretion from activated T cells and monocytes, or to convey a suppressive phenotype to effector CD4⁺CD25⁻ T cells. Treatment with antitumor necrosis factor α (TNFα; Infliximab) restored the capacity of regulatory T cells to inhibit cytokine production and to convey a suppressive phenotype to “conventional” T cells. Furthermore, anti-TNFα treatment led to a significant rise in the number of peripheral blood regulatory T cells in RA patients responding to this treatment, which correlated with a reduction in C reactive protein. These data are the first to demonstrate that regulatory T cells are functionally compromised in RA, and indicate that modulation of regulatory T cells by anti-TNFα therapy may be a further mechanism by which this disease is ameliorated.

Human gene expression first occurs between the four- and eight-cell stages of preimplantation development

The earliest stages of development in most animals, including the few mammalian species that have been investigated, are regulated by maternally inherited information. Dependence on expression of the embryonic genome cannot be detected until the mid two-cell stage in the mouse, the four-cell stage in the pig (J. Osborn & C. Polge, personal communication), and the eight-cell stage in the sheep. Information about the timing of activation of the embryonic genome in the human is of relevance not only to the therapeutic practice of in vitro fertilization and embryo transfer (IVF), but more importantly for the successful development of techniques for the preimplantation diagnosis of certain inherited genetic diseases. We describe here changes in the pattern of polypeptides synthesized during the pre-implantation stages of human development, and demonstrate that some of the major qualitative changes which occur between the four- and eight-cell stages are dependent on transcription. In addition, it appears that cleavage is not sensitive to transcriptional inhibition until after the four-cell stage.

CREB-binding protein/p300 are transcriptional coactivators of p65

CBP (CREB-binding protein) and p300 are versatile coactivators that link transcriptional activators to the basal transcriptional apparatus. In the present study, we identify CBP and p300 as coactivators of the nuclear factor-kappaB (NF-kappaB) component p65 (RelA). Consistent with their role as coactivators, both CBP and p300 potentiated p65-activated transcription of E-selectin and VCAM-1-CAT reporter constructs. The N- and C-terminal domains of both CBP/p300 functionally interact with a region of p65 containing the transcriptional activation domain as demonstrated by mammalian two-hybrid assays. Direct physical interactions of CBP/p300 with p65 were demonstrated by glutathione S-transferase fusion protein binding, and coimmunoprecipitation/Western blot studies. The adenovirus E1A 12S protein, which complexes with CBP and p300, inhibited p65-dependent gene expression. Reporter gene expression could be rescued from E1A inhibition by overexpression of CBP or p300. CBP and p300 act as coactivators of p65-driven gene activation and may play an important role in the cytokine-induced expression of various immune and inflammatory genes.

The Biomolecular Interaction Network Database and related tools 2005 update

The Biomolecular Interaction Network Database (BIND) (http://bind.ca) archives biomolecular interaction, reaction, complex and pathway information. Our aim is to curate the details about molecular interactions that arise from published experimental research and to provide this information, as well as tools to enable data analysis, freely to researchers worldwide. BIND data are curated into a comprehensive machine-readable archive of computable information and provides users with methods to discover interactions and molecular mechanisms. BIND has worked to develop new methods for visualization that amplify the underlying annotation of genes and proteins to facilitate the study of molecular interaction networks. BIND has maintained an open database policy since its inception in 1999. Data growth has proceeded at a tremendous rate, approaching over 100 000 records. New services provided include a new BIND Query and Submission interface, a Standard Object Access Protocol service and the Small Molecule Interaction Database (http://smid.blueprint.org) that allows users to determine probable small molecule binding sites of new sequences and examine conserved binding residues.

The effect of thrombocytopenia on experimental arteriosclerotic lesion formation in rabbits. Smooth muscle cell proliferation and re-endothelialization

This study was designed to investigate the mechanisms involved in fibromusculoelastic lesion formation produced by selective de-endothelialization by the intra-arterial balloon catheter technique in thrombocytopenic rabbits. Thrombocytopenia was induced and maintained for up to 30 days by daily injections fo highly specific sheep anti-rabbit platelet sera (APS). Evidence for re-endothelialization was obtained by i.v. Evans blue dye 30 min before sacrifice. Rabbits received daily injections of APS, which reduced the mean platelet count to 5,600/cm3; control animals received identically treated normal sheep sera on the same schedule, and had mean daily platelet counts of 363,000/cm3. Evaluation of intimal thickness was assessed by counting cell layers in semithin sections. Intimal thickening in aortae from rabbits treated with APS was strikingly suppressed, in contrast to those from normal sheep sera-treated animals which showed a mean intimal thickness of 18 cell layers within 28 days often after de-endothelialization. Re-endothelialization was not affected by APS treatment. These results indicate that the proliferation of smooth muscle cells is dramatically inhibited by reduction of platelets.

Twenty years of social capital and health research: a glossary

Research on social capital in public health is approaching its 20th anniversary. Over this period, there have been rich and productive debates on the definition, measurement and importance of social capital for public health research and practice. As a result, the concepts and measures characterising social capital and health research have also evolved, often drawing from research in the social, political and behavioural sciences. The multidisciplinary adaptation of social capital-related concepts to study health has made it challenging for researchers to reach consensus on a common theoretical approach. This glossary thus aims to provide a general overview without recommending any particular approach. Based on our knowledge and research on social capital and health, we have selected key concepts and terms that have gained prominence over the last decade and complement an earlier glossary on social capital and health.

Antioxidant activity of saliva and periodontal disease

The antioxidant activity of saliva has been investigated in 28 apparently healthy individuals and seven dental patients with periodontal disease. The results show that the major aqueous antioxidant component of whole saliva is uric acid, with lesser contributions from ascorbic acid and albumin. All are present at lower concentrations than those found in the plasma water. The total antioxidant activity (TAA) of saliva correlates (r2 = 0.972) with the concentration of uric acid, which contributes more than 70% of the TAA. Stimulation of salivary flow is associated with increased production of antioxidants. The antioxidant potential of saliva does not appear to be compromised in patients with periodontal disease but this may relate to the antioxidant flow from the gingival crevicular fluid.

Calcium influx via TRP channels is required to maintain PIP2 levels in Drosophila photoreceptors

The trp (transient receptor potential) gene encodes a Ca2+ channel responsible for the major component of the phospholipase C (PLC) mediated light response in Drosophila. In trp mutants, maintained light leads to response decay and temporary total loss of sensitivity (inactivation). Using genetically targeted PIP2-sensitive inward rectifier channels (Kir2.1) as biosensors, we provide evidence that trp decay reflects depletion of PIP2. Two independent mutations in the PIP2 recycling pathway (rdgB and cds) prevented recovery from inactivation. Abolishing Ca2+ influx in wild-type photoreceptors mimicked inactivation, while raising Ca2+ by blocking Na+/Ca2+ exchange prevented inactivation in trp. The results suggest that Ca2+ influx prevents PIP2 depletion by inhibiting PLC activity and facilitating PIP2 recycling. Without this feedback one photon appears sufficient to deplete the phosphoinositide pool of approximately 4 microvilli.

Adolescent risk-taking and the five-factor model of personality

The aim of this study was to investigate the links between adolescent risk-taking and personality in a comprehensive manner, as opposed to focusing on any one particular risk or personality factor as has occurred in much previous research. We conceptualized risk-taking broadly through use of the Adolescent Risk Questionnaire (ARQ) which yields information relating to risk judgements and behaviours in four areas (i.e. thrill-seeking risk behaviours, reckless risks, rebellious risks and antisocial risks). Personality was conceptualized using the Five-factor Model of personality, a comprehensive trait model of personality. The ARQ and the NEO Five-factor Inventory were administered to 459 school-based adolescents aged 11 to 18 years. Consistent with past research, younger adolescents and girls generally reported engaging in risk behaviours less frequently than older adolescents and boys. Also, younger adolescents and girls generally rated the ARQ behaviours as more risky than their older male counterparts. This was in line with the significant negative correlations found between risk judgements and risk behaviours of all types. Also consistent with past research, few age differences were found for the personality traits. Sex differences were evident, with female adolescents scoring higher on neuroticism, agreeableness and conscientiousness than male adolescents. Together, risk judgements, personality factors, age and sex were found to be significant predictors of risk behaviours; however, the personality factor of significance was found to differ depending upon the risk type. This was also true for age and sex which differed in importance depending upon the risk type. Overall, these factors were most successful in predicting rebellious risk-taking and least successful in predicting thrill-seeking.

A prospective study to investigate the relationship between periodontal disease and adverse pregnancy outcome

OBJECTIVE

This study aimed to investigate a relationship between maternal periodontal disease and preterm birth, low birth weight and late miscarriage.

DESIGN

Prospective study in a single centre.

SETTING

Guy's and St Thomas' Hospital Trust, London, UK between August 1998 and July 2001.

SUBJECTS AND METHODS

Pregnant women were recruited on attending an ultrasound scan at approximately 12 weeks of pregnancy. Subjects completed a questionnaire and underwent periodontal examination.

MAIN OUTCOME MEASURES

Plaque and bleeding scores, pocket probing depth and loss of attachment. Pregnancy outcome data was collected retrospectively, including gestational age and birth weight at delivery.

RESULTS

Data were collected for 3,738 subjects. Regression analysis indicated that there were no significant relationships between the severity of periodontal disease and either preterm birth (PTB) or low birth weight (LBW). In contrast, there did appear to be a correlation between poorer periodontal health and those that experienced a late miscarriage.

CONCLUSIONS

There was no association between either preterm birth or low birth weight and periodontal disease in this population. There is evidence of a correlation between markers of poorer periodontal health and late miscarriage.

Serial gadolinium-enhanced MRI in relapsing/remitting multiple sclerosis of varying disease duration

In the planning of MRI protocols to monitor disease activity in multiple sclerosis (MS), the clinical subtype needs to be considered. In this serial gadolinium-enhanced MRI study, we demonstrated differences between patients with early relapsing/remitting MS and benign MS in both the production of new lesions and the occurrence of enhancement.

Phase I dose-escalation and pharmacokinetic study of temozolomide (SCH 52365) for refractory or relapsing malignancies

Temozolomide, an oral cytotoxic agent with approximately 100% bioavailability after one administration, has demonstrated schedule-dependent clinical activity against highly resistant cancers. Thirty patients with minimal prior chemotherapy were enrolled in this phase I trial to characterize the drug's safety, pharmacokinetics and anti-tumour activity, as well as to assess how food affects oral bioavailability. To determine dose-limiting toxicities (DLT) and the maximum tolerated dose (MTD), temozolomide 100-250 mg m(-2) was administered once daily for 5 days every 28 days. The DLT was thrombocytopenia, and the MTD was 200 mg m(-2) day(-1). Subsequently, patients received the MTD to study how food affects the oral bioavailability of temozolomide. When given orally once daily for 5 days, temozolomide was well tolerated and produced a non-cumulative, transient myelosuppression. The most common non-haematological toxicities were mild to moderate nausea and vomiting. Clinical activity was observed against several advanced cancers, including malignant glioma and metastatic melanoma. Temozolomide demonstrated linear and reproducible pharmacokinetics and was rapidly absorbed (mean Tmax approximately 1 h) and eliminated (mean t1/2 = 1.8 h). Food produced a slight reduction (9%) in absorption of temozolomide. Temozolomide 200 mg m(-2) day(-1) for 5 days, every 28 days, is recommended for phase II studies.

Lactobacillus GG treatment during pregnancy for the prevention of eczema: a randomized controlled trial

BACKGROUND

Probiotic supplementation in early life may be effective for preventing eczema. Previous studies have suggested that prenatal administration may be particularly important for beneficial effects.

OBJECTIVE

We examined whether prenatal treatment with the probiotic Lactobacillus rhamnosus GG (LGG) can influence the risk of eczema during infancy.

METHODS

We recruited 250 pregnant women carrying infants at high risk of allergic disease to a randomized controlled trial of probiotic supplementation (LGG 1.8 × 10(10) cfu/day) from 36 weeks gestation until delivery. Infants were assessed during their first year for eczema or allergic sensitization. Immunological investigations were performed in a subgroup. Umbilical cord blood was examined for dendritic cell and regulatory T cell numbers and production of TGFβ, IL-10, IL-12, IL-13, IFN-γ and TNFα. Maternal breast milk was examined for total IgA, soluble CD14 and TGFβ.

RESULTS

Prenatal probiotic treatment was not associated with reduced risk of eczema (34% probiotic, 39% placebo; RR 0.88; 95% CI 0.63, 1.22) or IgE-associated eczema (18% probiotic, 19% placebo; RR 0.94; 95% CI 0.53, 1.68). Prenatal probiotic treatment was not associated with any change in cord blood immune markers, but was associated with decreased breast milk soluble CD14 and IgA levels.

CONCLUSIONS

Prenatal treatment with Lactobacillus rhamnosus GG was not sufficient for preventing eczema. If probiotics are effective for preventing eczema, then a postnatal component to treatment or possibly an alternative probiotic strain is necessary.

alpha-Synuclein implicated in Parkinson's disease catalyses the formation of hydrogen peroxide in vitro

Some rare inherited forms of Parkinson's disease (PD) are due to mutations in the gene encoding a 140-amino acid presynaptic protein called alpha-synuclein. In PD, and some other related disorders such as dementia with Lewy bodies, alpha-synuclein accumulates in the brain in the form of fibrillar aggregates, which are found inside the neuronal cytoplasmic inclusions known as Lewy bodies. By means of an electron spin resonance (ESR) spin trapping method, we show here that solutions of full-length alpha-synuclein, and a synthetic peptide fragment of alpha-synuclein corresponding to residues 61-95 (the so-called non-Abeta component or NAC), both liberate hydroxyl radicals upon incubation in vitro followed by the addition of Fe(II). We did not observe this property for the related beta- and gamma-synucleins, which are not found in Lewy bodies, and are not linked genetically to any neurodegenerative disorder. There is abundant evidence for the involvement of free radicals and oxidative stress in the pathogenesis of nigral damage in PD. Our new data suggest that the fundamental molecular mechanism underlying this pathological process could be the production of hydrogen peroxide by alpha-synuclein.

The isolation and characterisation of a platelet-specific beta-globulin (beta-thromboglobulin) and the detection of antiurokinase and antiplasmin released from thrombin-aggregated washed human platelets

A protein fraction was isolated from the supernatant of thrombin-aggregated washed human platelets and was shown, by immunodiffusion techniques, to contain a platelet-specific beta-globulin (beta-thromboglobulin) as the major component. A molecular weight of 35 800 was determined for beta-thromboglobin from the measured sedimentation coefficient of3.0 S and Stokes radius of 2.85 nm. Beta-Thromboglobin was detected in the serum from whole blood and the supernatant of 48-h-old platelet-rich plasma and 28-day-old citrated whole blood, but not in platelet-poor plasma. The fraction containing beta-thromboglobulin was shown to possess an antiurokinase activity but was devoid of antiplasmin activity. A further fraction of approximate molecular weight 70 000 was also isolated which contained an antiplasmin but was devoid of antiurokinase activity.

The concept of microglia in relation to central nervous system disease and regeneration

In a relatively short period of time, the microglial cell has gone from a strongly contested component of the central nervous system (CNS), to being recognised as one of the main players in the response to brain injury. Microglia are thought to arise from cells of haematopoietic origin, and enter the brain in response to naturally occurring cell death. As a result, the microglial cell is the representative of the immune system within the brain. However, the main role of microglia in the adult CNS is to respond to disruption of the homeostasis of the brain, whether that disruption comes from direct damage to neurons, neuronal degeneration or through disease. In this paper we investigate three main causes of cell death in the CNS: inherited degeneration, traumatic lesions and human diseases, and the microglial response to each. Then we examine the mechanisms by which microglia control their surroundings and the methods employed by these cells to instigate neuronal death. Recent observations suggest that under no conditions where neurons are dying or regrowing are microglia not involved, and control of microglia is likely to be just as important in regeneration as providing a favourable environment for neurons to grow. In short, microglia cannot be seen merely as cells of a certain type within the brain, possessing certain functions, but instead must be regarded as a concept that shapes the approaches taken to nervous system development, cell death, disease and trauma, and nervous system regeneration.

Simplification with abacavir-based triple nucleoside therapy versus continued protease inhibitor-based highly active antiretroviral therapy in HIV-1-infected patients with undetectable plasma HIV-1 RNA

OBJECTIVE

To assess the antiviral efficacy, safety and adherence in patients switched to an abacavir-containing nucleoside reverse transcriptase inhibitor (NRTI) regimen after long-term HIV-1 RNA suppression with a dual NRTI/protease inhibitor (PI) combination.

METHODS

In an open-label, multicentre study, patients receiving 2NRTI plus PI for at least 6 months, with a history of undetectable plasma HIV-1 RNA since the initiation of therapy and plasma HIV-1 RNA < 50 copies/ml at screening, were randomly assigned to replace the PI with abacavir (n = 105) or continue the same treatment (n = 106). Clinical assessments included plasma HIV-1 RNA, chemistry, haematology, lymphocyte counts, and adverse event reports. Adherence to treatment was assessed by patient self-report.

RESULTS

A significantly longer time to treatment failure was demonstrated in the abacavir arm compared with the PI arm (P = 0.03) while treatment failure was experienced by significantly more patients in the PI arm: 24 (23%) versus 12 (12%) (P = 0.03). Therapy-limiting toxicity led to treatment failure in eight versus 14 cases in the abacavir and PI arms, respectively, whereas virological rebound was the cause in four versus two cases. Significant reductions in cholesterol and non-fasting triglyceride plasma levels at 48 weeks were observed in the abacavir arm (P < 0.001 andP = 0.035, respectively). The number of patients reporting no difficulty in taking their therapy showed a marked increase from baseline in the abacavir arm.

CONCLUSION

The replacement of PI by abacavir in a triple combination regimen following prolonged suppression of plasma HIV-1 RNA provides continued virological suppression, significant improvements in lipid abnormalities and enhanced ease of dosing.

Neuronal density in the human retinal ganglion cell layer from 16-77 years

Literature assessing whether or not neurons (retinal ganglion cells and displaced amacrine cells) are lost from the retinal ganglion cell layer in mammals with age is still controversial, some studies finding a decrease in cell density and others not. To date there have been no studies estimating the total number of neurons in the retinal ganglion cell layer of humans throughout life. Recent studies have concentrated on the macular region and examined cell densities, which are reported to decrease during aging. In a study of the human retinal pigment epithelium (RPE), we showed that, while RPE cell number does not change, cell density increases significantly in central temporal retina (macular region) as the retina ages. We speculated that the increase in density represents a "drawing together" of the retinal sheet to maintain high cell densities, in this region of the neural retina, in the face of presumed cell loss from the ganglion cell layer due to aging. Here, therefore, we have sampled the entire ganglion cell layer of the human retina and estimated total neuron numbers in 12 retinae aged from 16 to 77 years. Human retinae, fixed in formalin, were obtained from the Queensland Eye Bank and whole-mounted, ganglion cell layer uppermost. The total number of neurons was lower in the older than younger retinae and neuronal density was lower in most retinal regions in older retinae. Retinal area increased with age and neuronal density fell throughout the retina with a mean reduction of 0.53% per year. However, the percentage reduction in density was much lower for the macular region, with a value of 0.29% per year. It is possible that this lesser reduction in cell density in the macula is a result of the drawing together of the retinal sheet in this region as we speculated from RPE data.