The complex interaction between APOE promoter and AD: an Italian case�Ccontrol study

The single nucleotide polymorphisms (SNPs) rs449647, rs769446 and rs405509 in the promoter region of the APOE gene have been variously suggested to be ɛ4-independent risk factors for Alzheimer''s disease (AD). A previous Italian study found that the rs449647 was significantly associated with late-onset AD. The aim of this study was to verify whether these APOE promoter SNPs are genetic risk factors for AD and to investigate their interaction with the common APOE polymorphism. A total of 169 clinically diagnosed AD patients and 99 cognitively intact age-matched controls were included in the study. Significant associations with AD independent from sex, age and APOE/ɛ4 status were found for rs449647 A/A and rs405509 G/G genotypes (positive), and rs449647 A/T and rs405509 T/T genotypes (negative). Haplotype frequency estimation at the APOE locus showed significant associations for the ATG4, ATT4 and ACG3 (positive) and ATT2, ATT3 and TCG3 (negative) haplotypes. Therefore this study confirms the role of the rs449647 A/A genotype as risk factor for AD in Italy and suggests that promoter genotypes and APOE haplotypes might have a complex function in AD-associated genetic risk factors.     

Heparan sulphate,its derivatives and analogues share structural characteristics that can be exploited,particularly in inhibiting microbial attachment

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.     

DNA analysis of cystic fibrosis in Brazil by direct PCR amplification from Guthrie cards

A 3 bp deletion of condon 508 (phenylalanine) of the cystic fibrosis (CF) gene constitutes the mutation of most CF chromosomes. The frequency of this mutation (referred to as ΔF508), varies considerably between populations, ranging form 26% of the CF mutations in Turkey to 88% in Denmark. To determine the frequency of the ΔF508 mutation in Brazilian Caucasoid CF patients, we used direct polymerase chain reacion (PCR) amplification of DNA obtained from dried blood spots on Guthrie cards, followed by ethidium bromide staining of gels. Although the overall frequency of the ΔF508 mutation was 47% of 380 CF chromosomes from Brazilian Caucasoids born in five different states, significant inter-state differences were observed, ranging from a ΔF508 frequency of 27% to 53%. While our method could be used to screen patients and their relatives for carrier testing and prenatal diagnosis, the efficacy of screening only for the ΔF508 mutation would be low, and would vary from state to state. Screening for a panel of local mutations will be needed to increase the mutation detection rate and optimize genetic counseling. © 1993 Wiley-Liss, Inc.     

Current epidemiology of mild cognitive impairment and other predementia syndromes.

A variety of clinically-defined predementia syndromes, with differing diagnostic criteria and nomenclature, have been proposed to describe nondisabling symptomatic cognitive deficits arising in elderly persons. Incidence and prevalence of different predementia syndromes vary as a result of different diagnostic criteria, sampling, and assessment procedures. The incidence rates of all predementia syndromes increase with age and are higher in subjects with less education; but age, educational background, and gender are not consistently related to prevalence rates. There is particular interest in "Mild Cognitive Impairment (MCI)" because this predementia syndrome is thought to be a prodromal phase of Alzheimer disease (AD). Several studies have suggested that most patients who meet MCI criteria will progress to AD, but rates of conversion to AD and dementia vary widely among studies. Furthermore, MCI definition is less consistent in population-based studies than clinical studies, in which progression to AD is also more consistent. To clarify the sources of discrepant findings in the literature, this review summarizes existing epidemiological studies of the defined clinical predementia syndromes and their progression to dementia.     

Interpreting the mechanisms of continuous renal replacement therapy in sepsis: the peak concentration hypothesis

Severe sepsis and septic shock are the primary causes of multiple organ dysfunction syndrome (MODS), which is the most frequent cause of death in intensive care unit patients. Many water-soluble mediators with pro- and anti-inflammatory action such as TNF, IL-6, IL-8, and IL-10 play a strategic role in septic syndrome. In intensive care medicine, blocking any one mediator has not led to a measurable outcome improvement in patients with sepsis. CRRT is a continuously acting therapy, which removes in a nonselective way pro- and anti-inflammatory mediators; "the peak concentration hypothesis" is the concept of cutting peaks of soluble mediators through continuous hemofiltration. Furthermore, there is evidence of increased efficacy of high-volume hemofiltration compared to conventional CVVH, and other blood purification techniques that utilize large-pore membranes or sorbent plasmafiltration are conceptually interesting.