2-Chloroacetamidine, a novel immunomodulator, suppresses antigen-induced mouse airway inflammation

BACKGROUND

Citrullination is a presently under-recognized posttranslational protein modification catalyzed by PAD enzymes. Immune responses to citrullinated neo-epitopes are identified in a growing number of inflammatory and autoimmune diseases. However, the involvement of hypercitrullination in the pathogenesis of bronchial asthma is still unknown.

METHODS

As main experimental tool, we examined the effect of 2-chloroacetamidine (2CA), a PAD enzyme inhibitor, on OVA-immunized and airway-challenged BALB/c mice; a commonly used model of allergic airway inflammation. We also measured the effect of 2CA on ex vivo lymphocytes and cell lines.

RESULTS

In vivo, 2CA dramatically suppressed lung tissue hypercitrullination, inflammatory cell recruitment, and airway-Th2 cytokine secretion. 2CA also suppressed systemic OVA-specific and total IgE production dramatically, effectively preventing de novo and diminishing established disease without measurably impacting general immunocompetence. In vitro, 2CA markedly inhibited the proliferation of mouse and human T cells with cell cycle block and apoptosis during a limited, postactivation phase.

CONCLUSIONS

2CA acts as narrow-spectrum immunosuppressant that selectively targets lymphocyte populations involved in active inflammatory tissue lesions. If hypercitrullination is generated in patients with asthma, 2CA may represent a novel disease modulator for human asthmatics/allergic diseases.

Psychological factors in association with uptake of voluntary counselling and testing for HIV among men who have sex with men in Hong Kong

OBJECTIVES

To investigate the prevalence and factors associated with uptake of voluntary counselling and testing (VCT) for human immunodeficiency virus (HIV) among men who have sex with men (MSM) in Hong Kong.

STUDY DESIGN

Cross-sectional study.

METHODS

A total of 389 MSM were recruited from gay venues. An additional 188 MSM were recruited through the Internet. Data were collected via face-to-face interviews using a self-administered anonymous questionnaire or via an electronic questionnaire accessible via local gay-friendly websites. The associations between independent and dependent variables (VCT uptake in lifetime and in last 12 months) were examined by logistic regression models.

RESULTS

The prevalence rates for lifetime and 12-month uptake of VCT were 56.5% and 39.4%, respectively. Adjusting for significant background variables, all cognitive variables (attitudes, subjective norms, perceived control and behavioural intention) that were derived from the Theory of Planned Behaviours (TPB) were significantly associated with both lifetime and 12-month uptake of VCT [adjusted odds ratio (AOR) 0.56-4.71, P < 0.05]. Perceived fear of contracting HIV and perceived discrimination towards local MSM were associated with a lower likelihood of 12-month uptake of VCT (AOR 0.63, P < 0.05) and lifetime uptake (AOR 0.65, P < 0.05). In the summary models, variables derived from the TPB (subjective norms, perceived control and behavioural intention) were independently associated with lifetime and 12-month uptake of VCT (OR 0.64-2.78, P < 0.05; OR 2.39-3.21, P < 0.05, respectively). Fear of contracting HIV was associated with VCT uptake in the last 12 months (OR 0.55, P < 0.05).

CONCLUSIONS

Psychological factors are associated with VCT uptake. The TPB and other health behavioural theories should be taken into account when designing VCT promotion campaigns.

Synergy between paclitaxel plus an exogenous methyl donor in the suppression of murine demyelinating diseases

Progressive demyelination in multiple sclerosis (MS) reflects the negative balance between myelin damage and repair due to physical and molecular barriers, such as astrocytic glial scars, between oligodendrocytes and target neurons. In this paper, we show that combination therapy with paclitaxel (Taxol) plus the universal methyl-donor, vitamin B12CN (B12CN), dramatically limits progressive demyelination, and enhances remyelination in several independent, immune and nonimmune, in vivo and in vitro model systems. Combination therapy significantly reduced clinical signs of EAE in SJL mice, as well as the spontaneously demyelinating ND4 transgenic mouse. Astrocytosis was normalised in parallel to ultrastructural and biochemical evidence of remyelination. The combination therapy suppressed T cell expansion, reduced IFN-gamma, while enhancing IFN-beta and STAT-1 expression, STAT-1 phosphorylation and methylation of STAT-1 and MBP in the brain. Paclitaxel/B12CN has nearly identical effects to the previously described combination of IFN-beta/ B12CN, whose clinical usefulness is transient because of IFN-neutralising antibodies, not observed (or expected) with the present drug combination. This report provides a mechanistic foundation for the development of a new therapeutic strategy in humans with MS.

Rebound intracranial hypertension after treatment of spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is characterized by orthostatic headache and the cause is usually cerebrospinal fluid leaks in spine level. Most patients with SIH have a benign course. Epidural blood patch (EBP) is the treatment of choice when initial conservative managements are ineffective. We reported a patient with SIH diagnosed by using magnetic resonance imaging and radionuclide cisternography. Acute rebound intracranial hypertension developed after EBP and was successfully treated with intravenous osmotic agent.

Monitoring community responses to the SARS epidemic in Hong Kong: from day 10 to day 62

STUDY OBJECTIVE

To report the evolution in perceptions and behaviours of the general public in response to the severe acute respiratory syndrome (SARS) epidemic in Hong Kong.

DESIGN

Ten similar and sequential telephone surveys were conducted during outbreak of SARS, which are classified as belonging to the first and second phases of the epidemic.

SETTING

Hong Kong, China.

PARTICIPANTS

1397 Hong Kong residents between 18 and 60 years of age.

MAIN OUTCOME MEASURES

Perceptions and behaviours to SARS and its prevention.

RESULTS

Most of the respondents believed that SARS could be transmitted via direct body contact and droplets. About half of respondents believed that SARS was curable, which increased in the initial phase and decreased in the second phase. Perceived chance of infection was low (9%) but fear of infection in public places was high (48%). Perceived efficacy of hygiene measures (wearing a mask: 82%, hand washing: 93%, and home disinfection: 75%) remained high in both phases and the perceived efficacy of avoiding crowded place, and using public transportation, etc, increased initially and decreased in the second phase. In parallel, use of the three hygiene measures increased significantly in the first phase and remained high for wearing a mask and washing hands in the second phase. Percentages of people avoiding crowded place and public transportation significantly increased initially and decreased in the second phase.

CONCLUSION

SARS related perceptions and behaviours evolved rapidly during the epidemic and Hong Kong residents quickly adopted appropriate SARS prevention measures. Timely dissemination of information seems effective in public health crises management.

Role of lymphocytes in collagen induced arthritis

We investigated the time related changes of lymphocyte subsets in the blood, regional lymph node and thymus during the development of collagen induced arthritis in mice. Flow cytometric analysis showed that Lyt2+ T, but not L3T4+ T cells in the blood or regional lymph node, was significantly reduced throughout the observation. The number of Lyt2+ T cells was decreased in lymph nodes of collagen immunized vs adjuvant controls while B cells were increased and L3T4+ T cells were not different. These might act as a potential factor for the onset of collagen induced arthritis. The reduction of Lyt2+ cells was not influenced by thymic T cell maturation; it is conceivable that the main immune organ is the regional lymph node.