Dynamic analysis based on the relapse rate of drug epidemic model

In this paper,we study a drug epidemic model based on epidemiology by dividing thehuman population into four classes at time t:susceptibles(S),drug users(1),drugusers who are treated in isolation and temporarily quit drugs(Q_(T))and drug users whoare treated in isolation and permanently quit drugs(Qp).We obtain the basic repro-duction number Ro of the model and perform its sensitivity analysis.We show that if R_(0)<β1A/μ(μ+δ1)<1,then the drug-free equilibrium is globally asymptotically stable,and if R_(0)>1,there exists an drug-abuse equilibrium and it is locally asymptoticallystable.The proposed model may possess forward and backward bifurcations.Moreover,three different control strategies and numerical results are presented.Through differentadjustments to obtain graphical results,we obtain the best strategy to control the drugepidemic.

Efficacy of early treatment with infliximab in pediatric Crohn’s disease

AIM: To investigate the effectiveness of early infliximab use for induction and maintenance therapy in pediatric Crohn’s disease. METHODS: We performed a retrospective chart review of 36 patients with Crohn’s disease. Ten patients (group A) were treated with mesalamine after induction therapy with oral prednisolone, and 13 patients (group B) were treated with azathioprine after induction therapy with oral prednisolone. Thirteen patients (group C) received infliximab and azathioprine for induction and maintenance therapy for the first year, and were treated with azathioprine after 1 year. All patients were followed for at least 24 mo. Efficacy was determined by the relapse rate using the pediatric Crohn’s disease activity index score in each group at 12 and 24 mo. RESULTS: At the 1 year follow-up, the relapse ratee, Mi Jin Kim, Hae Jeong Lee, Yon Ho Choe (23.1%, 3 of 13 patients) in group C was lower than that (61.5%, 8 of 13 patients) in group B (P = 0.047). At the 2 years follow-up, the relapse rate (38.5%, 5 of 13 patients) in group C was lower than that (76.9%, 10 of 13 patients) in group B (P = 0.047). Adverse events in group C were fewer than in groups A and B. CONCLUSION: Early induction with infliximab at diagnosis, known as "top-down" therapy, was effective for reducing the relapse rate compared to conventional therapies for at least 2 years.

Correlations Between Serum Uric Acid Level and Disease Activity,Intrathecal Inflammation Reactivity in Patients with Multiple Sclerosis

Objective To explore the correlations between serum uric acid （HA） levels and the clinical and cerebrospinal fluid （CSF） parameters of multiple sclerosis （MS）. Methods The medical reports of 47 MS patients admitted to Peking Union Medical College Hospi- tal during 2008 and 2010 were reviewed. And 49 age- and gender-matched cerebral infarction patients were enrolled as control. The mean serum HA level of the MS patients was compared with that of the control group. The correlations between the HA levels and the clinical parameters including gender, disease duration, relapse rate, and disease disabilities as assessed by the Expanded Disability Status Scale score, were explored. Forty-one patients had CSF examinations. The correlations between the IdA levels and the CSF parameters reflecting inflammation and tissue damage, including CSF protein, white blood cell count, oligoclonal band, 24-hour IgG index, and myelin basic protein, were also investigated. Results The mean serum HA level in the MS patients was lower than that in the control group （247.75 ± 52.59 jamol/L vs. 277.94 ± 74.33 pmol/L, P=0.025） and inversely correlated with the relapse rate （P=0.049）. MS patients with lower serum UA levels tended to have higher white blood cell counts and myelin basic protein level. But there was no correlation between CSF protein levels （r=0.165, P=0.273）, white blood cell counts （r=-0.051, P=0.732）, IgG index （r =0. 045, P=0.802）, or myelin basic protein level （r =-0.248, P=0.145） and the serum UA level, respectively. Conclusion In MS patients, UA levels might partly reflect the extent of disability and inflammation.