Plasma Concentrations Of Aβ42 Research Articles

Effect of dexmedetomidine on postoperative cognitive function in patients with mild hyperbilirubinemia caused by choledocholithiasis

Objective To evaluate the effect of dexmedetomidine on postoperative cognitive function in the patients with mild hyperbilirubinemia caused by choledocholithiasis. Methods One hundred and twenty patients of both sexes with mild hyperbilirubinemia (serum total bilirubin levels 21-170 μmol/L) caused by choledocholithiasis, aged 51-63 yr, with body mass index of 20-28 kg/m2, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, with preoperative Mini-Mental State Examination (MMSE) scores≥20, scheduled for elective cholecystectomy and choledocholithotomy, were divided into 3 groups (n=40 each) using a random number table method: control group (C group) and dexmedetomindine 0.4 μg·kg-1·h-1 group (D1 group) and dexmedetomindine 0.6 μg·kg-1·h-1 group (D2 group). After induction of anesthesia, dexmedetomidine was intravenously infused for 10 min in a loading dose of 0.5 μg/kg, followed by an infusion of 0.4 and 0.6 μg·kg-1·h-1 until the end of operation in D1 and D2 groups, respectively.The equal volume of normal saline was given instead in group C. with preoperative scores≥20, MMSE and Montreal Cognitive Assessment (MoCA) were used to assess the cognitive function at 1 day before operation (T0) and 1, 3, 5 and 7 days after operation (T1-4). The occurrence of cognitive dysfunction within 7 days after operation was recorded.Venous blood samples were collected at the time points mentioned above, and the plasma concentrations of β-amyloid (Aβ) 42 were determined by enzyme-linked immunosorbent assay. Results Compared with group C, MoCA scores were significantly increased at T1 in group D1, and MMSE scores at T1 and MoCA scores at T1 and T2 were significantly increased, and the plasma concentrations of Aβ42 were decreased at T2-4 in group D2, and the incidence of cognitive dysfunction was significantly decreased in D1 and D2 groups (P<0.05). Compared with group D1, MoCA scores were significantly increased at T1, and the plasma concentrations of Aβ42 were decreased at T2-4 in group D2 (P<0.05). Conclusion Dexmedetomidine can improve postoperative cognitive function, and intravenous infusion at a rate of 0.6 μg·kg-1 · h-1 provides better efficacy for the patients with mild hyperbilirubinemia caused by choledocholithiasis. Key words: Dexmedetomidine; Cognition disorders; Postoperative complications; Hyperbilirubinemia; Cholelithiasis

SORL1 gene, plasma biomarkers, and the risk of Alzheimer's disease for the Han Chinese population in Taiwan.

BackgroundThe sortilin-related receptor 1 (SORL1) gene, regulating the trafficking and recycling of amyloid precursor protein, has been related to Alzheimer’s disease (AD) and mild cognitive impairment (MCI). The aim of the present study was to investigate the relationship between SORL1 polymorphisms, plasma concentrations of amyloid-beta (Aβ) isoforms, and AD and MCI susceptibility for a Han Chinese population in Taiwan.MethodsEight single-nucleotide polymorphisms (SNPs) in SORL1 and the apolipoprotein E gene (APOE) ε4 alleles were genotyped in 798 patients with AD, 157 patients with MCI, and 401 control subjects. Plasma concentrations of Aβ42, Aβ40, and neuropsychiatric tests for six different cognitive domains were examined.ResultsAmong the eight tested SNPs, SORL1 rs1784933 was most significantly associated with AD and MCI in our population. The G allele of rs1784933 exerted a protective effect and was associated with a reduced risk of AD (odds ratio [OR] = 0.75, p = 0.004) and MCI (OR = 0.69, p = 0.013). The significance remained after we adjusted for age, sex, and APOE ε4 alleles. For the overall participants, the plasma concentrations of Aβ42 were nominally significant for subjects carrying the rs1784933 G allele having a lower level than those without the G allele (p = 0.046). There was a similar trend for the G allele carriers to have a lower plasma Aβ40 level than noncarriers, but this was not significant. The nonsynonymous SNP rs2298813 was also related to a lower disease risk when AD and MCI were combined as a group (OR = 0.76, p = 0.035). However, there was no association between SORL1 genotypes and any of the six cognitive tests.ConclusionsFindings from our study provide support for the effect of SORL1 gene on the disease risks and pathognomonic surrogates of AD/MCI. The interaction between SORL1 polymorphisms and Aβ formation requires further study.

Plasma levels of Aβ peptides are altered in amnestic mild cognitive&#x0D; impairment but not in sporadic Alzheimer’s disease

Plasma Aβ levels have been examined in sporadic Alzheimer’s disease yielding conflicting results; both no difference and an increase in plasma concentrations of Aβ42 and Aβ40 in sporadic cases of AD as compared to controls have been reported. Elevated plasma Aβ42 levels may be detected several years before the onset of symptoms (in mild cognitive impairment stadium). Levels of Aβ40 and Aβ42 were measured in plasma from 54 patients with AD, 39 subjects with MCI and 35 controls using a commercially available ELISA. Mean plasma Aβ42 levels were significantly higher in MCI as compared to both AD (P

Standardization of measurement of β-amyloid(1-42) in cerebrospinal fluid and plasma

The standardization and clinical validation of the measurement of β–amyloid. (Aβ42) in cerebrospinal fluid (CSF), plasma and urine is described using a commercially available sandwich–type ELISA with 2 IF12 and 3D6 as monoclonal antibodies. The INNOTEST™ β–amyloid(1–42) allows the specific and reliable measurement of (1–42) amyloid peptides in CSF and plasma. The Aβ42 concentrations in serum and urine were below the detection limit. In plasma, no differences were found in Aβ42 levels between controls and patients with different neurodegenerative disorders (Alzheimer's disease (AD), Lewy body disease (LED), others). In contrast, CSF–Aβ42 concentrations were lower in AD and LBD patients as compared to controls. No correlation was found in AD patients between CSF and plasma concentrations of Aβ42 or between CSF Aβ42 levels and blood–brain–barrier function. The quantitative outcome of the test is in part dependent on confounding factors such as tube type, freeze/thaw cycles, temperature of incubation, standard preparation protocol, and antibody selection. Notwithstanding these aspects, it emerged that Aβ42 is a useful biochemical marker for the diagnosis of AD patients, but there is a need for an international Aβ standard, a universally accepted protocol for CSF preparation, and a thorough evaluation of assay performance in function of the boundary conditions.