RESUMO
Heparan sulphate (HS) and the related polysaccharide, heparin, exhibit conformational and charge arrangement properties, which provide a degree of redundancy allowing several seemingly distinct sequences to exhibit the same activity. This can also be mimicked by other sulphated polysaccharides, both in overall effect and in the details of interactions and structural consequences of interactions with proteins. Together, these provide a source of active compounds suitable for further development as potential drugs. These polysaccharides also possess considerable size, which bestows upon them an additional useful property: the capability of disrupting processes comprising many individual interactions, such as those characterising the attachment of microbial pathogens to host cells. The range of involvement of HS in microbial attachment is reviewed and examples, which include viral, bacterial and parasitic infections and which, in many cases, are now being investigated as potential targets for intervention, are identified.
Assuntos
Humanos , Bactérias/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Heparitina Sulfato/química , Heparitina Sulfato/farmacologia , Polissacarídeos/química , Heparina/química , Heparina/farmacologia , Propriedades de SuperfícieRESUMO
Heparan sulphate (HS) and the related polysaccharide, heparin, exhibit conformational and charge arrangement properties, which provide a degree of redundancy allowing several seemingly distinct sequences to exhibit the same activity. This can also be mimicked by other sulphated polysaccharides, both in overall effect and in the details of interactions and structural consequences of interactions with proteins. Together, these provide a source of active compounds suitable for further development as potential drugs. These polysaccharides also possess considerable size, which bestows upon them an additional useful property: the capability of disrupting processes comprising many individual interactions, such as those characterising the attachment of microbial pathogens to host cells. The range of involvement of HS in microbial attachment is reviewed and examples, which include viral, bacterial and parasitic infections and which, in many cases, are now being investigated as potential targets for intervention, are identified.
Assuntos
Bactérias/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Heparitina Sulfato/química , Heparitina Sulfato/farmacologia , Polissacarídeos/química , Heparina/química , Heparina/farmacologia , Humanos , Propriedades de SuperfícieRESUMO
The purpose of this study was to determine the magnitude and distribution of acute gastrointestinal illness (GI) in the Chilean population, describe its burden and presentation, identify risk factors associated with GI and assess the differences between a 7-day, 15-day and a 30-day recall period in the population-based burden of illness study design. Face-to-face surveys were conducted on 6047 randomly selected residents in the Metropolitan region, Chile (average response rate 75·8%) in 2008. The age-adjusted monthly prevalence of GI was 9·2%. The 7-day recall period provided annual incidence rate estimates about 2·2 times those of the 30-day recall period. Age, occupation, healthcare system, sewer system, antibiotic use and cat ownership were all found to be significant predictors for being a case. This study expands on the discussion of recall bias in retrospective population studies and reports the first population-based burden and distribution of GI estimates in Chile.
Assuntos
Gastroenterite/epidemiologia , População Urbana , Adolescente , Adulto , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Chile/epidemiologia , Feminino , Gastroenterite/patologia , Humanos , Lactente , Recém-Nascido , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Adulto JovemRESUMO
We evaluated the anti Vi test to detect S typhi carriers in 1006 food handlers of 65 locations in central Santiago (Chile): 710 males and 296 females, age range 17 to 67. Positive reactions were found in 27 subjects, titers varying from 1/40 in 9 to 1/160 in 1 subject. Culture of feces, along with urine and bile cultures in those with very high titers allowed isolation of S typhi in 2 subjects, one with a 1/40 titer, the other 1/160. None had clinical history of typhoid fever, both had received parenteral vaccination. These results compare favorably with the classic technique which would have required 3018 fecal cultures (vs 108 in the present study) and a total cost of US$ 1730 vs US$ 364. In addition, anti-Vi detection is readily accepted by the subjects. Therefore, we recommend this technique as a screening prior to culture techniques in the identification of chronic S typhi carriers.