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991.
1984年我们对北京地区的乙型脑炎病毒和M14病毒进行了监测,观察到三带喙库蚊季节消长高峰在8月中旬,较发病率较高的1980年和1981年晚3周左右:乙型脑炎病毒检出率(批)为16.1%,最低现场感染率为1:303,检出高峰在8月中旬(44.0%),较1981年晚2周以上;到8月初才发现所感染的猪,明显晚于1980年和1981年,受上述众因素的影响,本年度本市乙型脑炎发病率仍较低(0.8/10万),在M14病毒的监测中,发现三带喙库蚊环病毒M14病毒检出率为9.32%,最低现场感染率为1:526,当年最高检出率(32%)和最低现场感染率高峰(1:156),高峰出现在8月30日,与乙脑病毒自然感染率出现的高蜂相一致;猪感染M14病毒与感染乙脑病毒的时间基本相同,表明这两种病毒在自然界传播中不存在明显的互相干扰关系,乙脑低流行年的出现并未受到M14病毒的影响。 相似文献
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Matsumoto M Sakae K Hashikawa S Torii K Hasegawa T Horii T Endo M Okuno R Murayama S Hirasawa K Suzuki R Isobe J Tanaka D Katsukawa C Tamaru A Tomita M Ogata K Ikebe T Watanabe H Ohta M;Working Group for Group A Streptococci in Japan 《Microbiology and immunology》2005,49(10):925-929
DNase B is a major nuclease and a possible virulence factor in Streptococcus pyogenes. The allelic diversity of streptococcal DNase B (sdaB) gene was investigated in 83 strains with 14 emm genotypes. Of the 15 alleles identified, 11 alleles carried only synonymous nucleotide substitutions. On the other hand, 4 alleles had a non-synonymous substitution other than synonymous substitutions, resulting in the substitution of a single amino acid. The distribution of each allele was generally emm genotype-specific. Only sdaB7 was found in both emm2 and emm4. The promoter region was highly conserved and DNase B protein was similarly expressed in all alleles. 相似文献
997.
Mehta RH Manfredini R Bossone E Fattori R Evagelista A Boari B Cooper JV Sechtem U Isselbacher EM Nienaber CA Eagle KA;International Registry of Acute Aortic Dissection 《Chronobiology international》2005,22(4):723-729
We recently reported the existence of a higher risk of acute aortic dissection (AAD) during the winter months. However, it is not known whether this winter peak is affected by climate. To address this issue, we evaluated data from 969 AAD patients who were enrolled at various sites around the globe and who were participating in the International Registry of Acute Aortic Dissection (IRAD). We found a significant (p=0.001; χ2 test) difference in the number of AAD events occurring during the different seasons of the year, with highest incidence in winter (28.4%) and lowest incidence in summer (19.9%). Furthermore, the winter peak was evident in both cold and temperate climate settings, suggesting that the relative change in temperature, rather than absolute temperature, and/or endogenous annual rhythms are critical mechanistic factors. 相似文献
998.
David Scheifele Scott Halperin Barbara Law Arlene King for The Canadian Paediatric Society / Health Canada Immunization Monitoring Program Active 《CMAJ》2005,172(1):53-56
Background
Although vaccination of infants against Haemophilus influenzae type b (Hib) invasive infections is effective and has been routinely available in Canada since 1992, cases of the disease continue to occur. We were interested in determining whether recent cases of Hib infection reflected progressive loss of protection with time since vaccination, increasing nonacceptance of vaccination or a deleterious effect of coadministration of recently introduced vaccines such as those for pneumococcal and meningococcal conjugates and hepatitis B. We report on the causes of Hib infections among vaccinated and unvaccinated children between 2001 and 2003 in Canada.Methods
Through our established network of 12 pediatric tertiary care hospitals we actively searched for cases in each centre by reviewing daily admissions and laboratory reports, visiting the wards and checking discharge diagnosis codes. Culture-confirmed cases were summarized by nurse monitors using a standardized reporting system.Results
We identified 29 cases during the 3 years: 16 in 2001, 10 in 2002 and 3 in 2003. Half of the 29 patients had meningitis. Hib infection was more common among children less than 6 months of age (11 cases) and in boys (20 cases). Two deaths occurred (7% case-fatality ratio). A total of 20 children had received no or incomplete primary vaccination because of parental refusal (7 cases), because they were too young to have completed the primary series (11 cases, including 1 in which parental refusal was also a factor) or because of delays in completing the primary series (2 cases); the vaccination history was uncertain in the remaining case. Infection despite primary vaccination occurred in 9 children: 2 previously healthy children and 7 who were immunocompromised or who had a predisposing condition. None of the cases identified in 2003 involved children who had received any of the newly introduced vaccines.Interpretation
Invasive Hib infections remain rare in Canada, with most cases occurring in children too young to have completed the primary series. Protection after vaccination appears to extend into later childhood and does not appear to be diminished by coadministration of newer infant vaccines.Until recently Haemophilus influenzae type b (Hib) was a leading cause of meningitis, epiglottitis and other invasive infections in children, affecting about 1 child in 250 by 5 years of age.1 The risk of infection was highest among children 6–24 months of age. Antibodies directed against the Hib capsular polysaccharide (polyribosyl ribitol phosphate, PRP) form the basis of protection. PRP protein conjugate vaccines that elicit anti-PRP responses in young infants have been used in Canada since 1992. Doses are recommended at 2, 4 and 6 months of age to establish protection and at 18 months to reinforce it. Since 1995 all provinces have used the same Hib vaccine (a PRP–tetanus protein conjugate [PRP-T], produced by Aventis Pasteur), in combination products based on whole-cell pertussis vaccines (from 1995 to 1997) or acellular pertussis vaccines (1998 to the present).Invasive Hib infections have been monitored since 1992 by a network of Canadian pediatric hospitals known as the Immunization Monitoring Program, Active (IMPACT).2 In 1985, before the first Hib vaccine was licensed, 485 invasive Hib cases were seen at 10 centres (those participating in IMPACT when the “look-back” was done).3 Case totals fell progressively as better vaccines became available.3,4,5 In 2000, only 4 cases were recorded by the IMPACT centres (which by then numbered 12), 99% fewer than in 1985.6 Continuing surveillance is important to assess the effectiveness of the current schedule and vaccine. Because Hib vaccination is relatively new, the question of duration of protection remains open. Resurgence of Hib disease occurred recently in the United Kingdom,7 prompting addition of a booster dose to the vaccination schedule (as in Canada). Other questions of relevance are whether nonacceptance of Hib vaccine is influencing case totals and whether coadministration of newer vaccines, such as those for pneumococcal and meningococcal group C conjugates and hepatitis B, is adversely affecting Hib responses. A reduced response is most likely to occur when infants are given conjugate vaccines containing the same carrier protein,8 which is not the case with PRP-T and pneumococcal conjugate vaccines; however, their compatibility has not been formally demonstrated to date. In this report we present details of cases encountered by IMPACT in the period 2001 to 2003. 相似文献999.
Michael D. Hill Alastair M. Buchan for The Canadian Alteplase for Stroke Effectiveness Study Investigators 《CMAJ》2005,172(10):1307-1312
Background
Thrombolysis for acute ischemic stroke has remained controversial. The Canadian Alteplase for Stroke Effectiveness Study, a national prospective cohort study, was conducted to assess the effectiveness of alteplase therapy for ischemic stroke in actual practice.Methods
The study was mandated by the federal government as a condition of licensure of alteplase for the treatment of stroke in Canada. A registry was established to collect data over 2.5 years for stroke patients receiving such treatment from Feb. 17, 1999, through June 30, 2001. All centres capable of administering thrombolysis therapy according to Canadian guidelines were eligible to submit patient data to the registry. Data collection was prospective, and follow-up was completed at 90 days after stroke. Copies of head CT scans obtained at baseline and at 24–48 hours after the start of treatment were submitted to a central panel for review.Results
A total of 1135 patients were enrolled at 60 centres in all major hospitals across Canada. The registry collected data for an estimated 84% of all treated ischemic stroke patients in the country. An excellent clinical outcome was observed in 37% of the patients. Symptomatic intracranial hemorrhage occurred in only 4.6% of the patients (95% confidence interval [CI] 3.4%–6.0%); however, 75% of these patients died in hospital. An additional 1.3% (95% CI 0.7%–2.2%) of patients had hemiorolingual angioedema.Conclusions
The outcomes of stroke patients undergoing thrombolysis in Canada are commensurate with the results of clinical trials. The rate of symptomatic intracranial hemorrhage was low. Stroke thrombolysis is a safe and effective therapy in actual practice.Thrombolytic therapy for stroke was first reported in 19581 and a subsequent small trial was reported in 19632 in the absence of brain parenchymal imaging but guided by angiography. The later arrival of CT scanning was an enabling technological event, and early dose-finding trials were begun in the 1980s,3,4,5 with large randomized trials conducted a decade later. Results of randomized trials of streptokinase therapy for ischemic stroke were uniformly negative.6,7,8 Results of trials of tissue plasminogen activator (tPA) were mixed in their respective primary analyses9,10,11,12,13 but overall showed a benefit that wanes as time from symptom to treatment elapses.14,15 A meta-analysis of randomized controlled trials showed that 55 fewer patients per 1000 treated with tPA within 6 hours after stroke would be dead or dependent at the end of follow-up compared with patients given placebo.16 Nevertheless, use of thrombolysis for stroke remains controversial, particularly because it is unclear whether such a therapy that is dependent on time, technology and infrastructure can be broadly and safely applied.In Canada, tPA therapy for stroke was conditionally licensed in 1999. As a condition of approval, a prospective registry to monitor safety was mandated by the federal government. The Canadian Alteplase for Stroke Effectiveness Study (CASES) was launched to collect data on outcomes for all patients treated with tPA in Canada. The purposes of the study were (a) to assess the safety of alteplase for stroke in the context of routine care and (b) to assess whether efficacy demonstrated in randomized clinical trials could be translated into effectiveness in clinical practice. 相似文献1000.
Clarification of the nomenclature for MSC: The International Society for Cellular Therapy position statement 总被引:25,自引:0,他引:25
Horwitz EM Le Blanc K Dominici M Mueller I Slaper-Cortenbach I Marini FC Deans RJ Krause DS Keating A;International Society for Cellular Therapy 《Cytotherapy》2005,7(5):393-395
The plastic-adherent cells isolated from BM and other sources have come to be widely known as mesenchymal stem cells (MSC). However, the recognized biologic properties of the unfractionated population of cells do not seem to meet generally accepted criteria for stem cell activity, rendering the name scientifically inaccurate and potentially misleading to the lay public. Nonetheless, a bona fide MSC most certainly exists. To address this inconsistency between nomenclature and biologic properties, and to clarify the terminology, we suggest that the fibroblast-like plastic-adherent cells, regardless of the tissue from which they are isolated, be termed multipotent mesenchymal stromal cells, while the term mesenchymal stem cells is used only for cells that meet specified stem cell criteria. The widely recognized acronym, MSC, may be used for both cell populations, as is the current practice; thus, investigators must clearly define the more scientifically correct designation in their reports. The International Society for Cellular Therapy (ISCT) encourages the scientific community to adopt this uniform nomenclature in all written and oral communications. 相似文献