Rosane Scheibe

Is MTHFR polymorphism a risk factor for Alzheimer's disease like APOE?

BACKGROUND The role of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms as risk factors for the occurrence of Alzheimers disease (AD) is still controversial. OBJECTIVE To verify the association between MTHFR and apolipoprotein E (APOE) polymorphisms and Alzheimers disease. METHOD This work was conducted as a case-control study. Cases included thirty patients with probable AD. Controls were constituted by 29 individuals without dementia according to neuropsychological tests paired to age, sex, race and educational level. DNA was isolated from peripheral leukocytes of anticoagulated venous blood. Genotyping of APOE and MTHFR were performed by DNA amplification and digestion. The frequences of APOE and MTHFR genotypes were submitted by chi-square test corrected by Fisher test; the APOE genotypes, to chi-square linear tendency test and the frequences of MTHFR mutant and AD, by stratificated analysis adjust by Mantel-Haenszel method. RESULTS There was significant difference about APOE4 and APOE2 in the groups. (p=0.002) The odds ratio increased exponentially with the increased number of E4 allele (chi2 linear tendency test). No significant difference was detected on MTHFR genotypes in both case and control groups. CONCLUSION The APOE4 is a risk factor and demonstrated a dose-dependent effect while APOE2 allele conferred a protection to AD. The MTHFR mutation had no correlation with AD.

Analysis of the Association Between Apolipoprotein E Polymorphism and Cardiovascular Risk Factors in an Elderly Population with Longevity

OBJECTIVE To establish the allelic and genotypic frequencies related to apolipoprotein E (ApoE) polymorphism and association of the genotypes with risk factors and cardiovascular morbidity in an elderly population with longevity. METHODS We analyzed 70 elderly patients aged 80 years or more who were part of the Projeto Veranópolis. We used the gene amplification technique through the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and cleavage with the restriction enzyme Hha I to identify the ApoE genotypes. The most frequent genotypes were compared considering biological variables and cardiovascular risks and morbidity. RESULTS The frequencies of the E2, E3, and E4 alleles were 0.05, 0.84, and 0.11, respectively, and of the genotypes were as follows: E3E3 (0.70), E3E4 (0.22), E2E3 (0.06), and E2E2 (0.02). Individuals with the E3E4 had a mean age greater than those with the E3E3. No association was observed between the genotypes and the variables analyzed, except for obesity, which was associated with the E3E3 genotype. Individuals with the E3E4 genotype had high levels of LDL-cholesterol and fibrinogen as compared with those with the E3E3 genotype. CONCLUSION The results suggest that the E4E4 genotype may be associated with early mortality. A balance between the protective or neutral factors and the cardiovascular risk factors may occur among the individuals with different genotypes, attenuating the negative effects of the E4 allele.

Agar diffusion, agar dilution, Etest®, and agar screening test in the detection of methicillin resistance in staphylococci

Methicillin resistant Staphylococcus is an important worldwide problem. Resistance is verified in strains harboring the mecA gene and laboratory methods used to detect resistance are object of constant investigation. In the present study, 99 clinical isolates of staphylococci (41 S. aureus, 33 S. epidermidis, 12 S. saprophyticus and 13 members of other species) were submitted to different phenotypic methods and conditions. Detection of the mecA gene by PCR was used as the reference method and detected 14/41, 10/33, and 10/25 isolates of S. aureus, S. epidermidis and other species, respectively. Results showed that, for S. aureus and S. epidermidis, agar diffusion, agar dilution, and the E test incubated during 24h at 35 degrees C correctly discriminated mecA positive from mecA negative isolates. For other species, all methods and conditions presented low specificity (ranging from 20% to 66.7%) and, particularly S. saprophyticus, may need molecular methods to correctly assess methicillin resistance.

A reação em cadeia da polimerase na detecção da resistência à penicilina em Streptococcus pneumoniae

INTRODUCAO: O Streptococcus pneumoniae e o mais frequente agente etiologico de infeccoes respiratorias adquiridas na comunidade e sua resistencia aos antimicrobianos tem aumentado nos ultimos anos. A determinacao da resistencia e feita rotineiramente por metodo lento que depende do crescimento em cultura e determinacao da concentracao inibitoria minima (CIM). A reacao em cadeia da polimerase (PCR) detecta os genes responsaveis pela resistencia do Streptococcus pneumoniae a penicilina em cerca de 8 horas. OBJETIVO: Comparar a PCR com o metodo da CIM no diagnostico da resistencia da Streptococcus pneumoniae a penicilina. METODO: Foram estudadas 153 amostras de Streptococcus pneumoniae, isoladas de diferentes sitios anatomicos, usando-se para deteccao de mutacoes nos genes que codificam as proteinas ligadoras de penicilina 1a, 2b e 2x, responsaveis pela resistencia a penicilina. A ocorrencia das mutacoes foi correlacionada com a CIM de penicilina, determinada pelo teste de difusao em agar. RESULTADOS: A resistencia global a penicilina do Streptococcus pneumoniae foi de 22,8% (16,3% de resistencia intermediaria e 6,5% de resistencia alta). Em proporcoes estatisticamente significativas, as amostras sensiveis a penicilina nao tinham mutacoes, as intermediarias apenas uma, geralmente na proteina ligadora de penicilina 2x, e as altamente resistentes tinham mutacoes nas tres proteinas investigadas. CONCLUSAO: A PCR e um metodo rapido para a deteccao da resistencia a penicilina do Streptococcus pneumoniae, que podera vir a ser utilizado na pratica clinica.

P1-302: MTHFR and APOE polymorphisms in a case-control study of Alzheimer’s disease

aging. This observation is consistent with the idea that the gradual downregulation of NEP expression, resulting in a corresponding elevation in the steady-state levels of A , over a decade or more, may cause A accumulation that triggers the AD pathological cascade. Additionally, higher mRNA levels of IDE and NEP were detected in the human cerebellum than in the frontal cortex, which may partly explain why cerebellum exhibits only minor plaque pathology. Conclusions: These data suggest that ageand region-specific changes in the proteolytic clearance of A make an important contribution to pathogenic mechanisms in AD.