The apolipoprotein E e4 polymorphism is strongly associated with poor mobility performance test results but not self-reported limitation in older people.

BACKGROUND: The apolipoprotein E (ApoE) e4 polymorphism is linked to increased mortality rates, Alzheimer's disease, and cardiovascular disease in older people, but previous studies have largely failed to detect an effect on self-reported mobility disability. We hypothesized that poor performance on mobility-related tests may provide a better measure of effects, and we aimed to estimate the extent to which the ApoE e4 allele increases risks of poor performance on measured mobility and self-reported mobility disability compared to e3/3, in a medium-sized population cohort. METHODS: Data were from 1262 people at baseline older than 65 years from the Longitudinal Aging Study Amsterdam (LASA), followed up for 6 years. Age- and sex-adjusted logistic regression models were used to explore associations. RESULTS: At baseline, those individuals with an e4 allele had an odds ratio of 2.26 (95% confidence interval, 1.31-3.90) for poor performance on gait speed testing (<0.4 m/s) and 1.94 (95% confidence interval, 1.19-3.16) for five chair stands (> or =20 s), compared to those with e3/3 status. At follow-up, associations between e4 status and incident poor performance on the chair stand test was significant. Associations with self-reported inability or need for help walking for 5 minutes or for climbing 15 steps were nonsignificant throughout. CONCLUSIONS: The ApoE e4 polymorphism is associated with a substantial excess of mobility limitation. The impact is detectable by performance testing, but not by self-reports. Poor results on mobility performance tests may provide a phenotype of ageing.

The transmethylation cycle in the brain of Alzheimer patients.

Homocysteine accumulation, frequently observed in plasma of AD patients, may be a sign of a reduced activity of the brain methionine-homocysteine transmethylation cycle. S-Adenosylmethionine (SAM) is the main methyl donor in several transmethylation reactions. The demethylated product of SAM, S-adenosylhomocysteine (SAH), is hydrolyzed to yield homocysteine, which can be remethylated to methionine by transfer of a methyl group of 5-methyltetrahydrofolate (5-MTHF). A reduced activity of the transmethylation cycle in the brain may result in hypomethylation of the promoter of the presenilin 1 (PS1) gene, which will lead to overexpression of presenilin 1 and, consequently, to increased Abeta(1-42) (Abeta42) formation. Brain transmethylation was studied in 30 patients with 'probable' AD and 28 age-matched non-demented controls by measuring the cerebrospinal fluid (CSF) levels of SAM, SAH and 5-MTHF. 5-MTHF was determined by HPLC with electrochemical detection, while SAM and SAH were assayed by stable isotope dilution tandem mass spectrometry. We found no statistical differences between AD patients and controls for 5-MTHF, SAM and SAH levels, and the SAM/SAH-ratio in CSF. These findings argue against a possible change in methylation of the promoter and expression of PS1.

The impact of heparin coated circuits upon metabolism in vital organs: effect upon cerebral and renal function during and after cardiopulmonary bypass.

During cardiopulmonary bypass (CPB), the brain and the kidneys may be damaged because of microemboli, ischemia, and inflammation. The latter has been reduced by the use of heparin coated circuits. We questioned whether heparin coated circuits could also reduce cerebral and renal damage and whether inflammatory markers correlate with damage to the brain and the kidneys. Fifty-one patients scheduled for coronary artery bypass grafting were perfused with either a heparin coated or an uncoated circuit. To compare the effect of a heparin coated circuit with an uncoated circuit upon cerebral and renal function in relation to inflammation, we assessed markers of cerebral (S100beta) and renal (N-acetyl-beta-D-glucosaminidase [NAG], creatinine, and urea) function, inflammation, and oxygen metabolism. S100beta levels and NAG levels increased during CPB in both groups as compared with baseline levels (p < 0.01), without differences between the groups. After 15 minutes on CPB, C4b/c levels were significantly higher in the coated group compared with the uncoated group (p < 0.02). C4b/c correlated with S100beta (p < 0.01). Total body oxygen delivery (DO2) and consumption (VO2) decreased significantly in both groups during CPB (p < 0.01), but recovery was better in the coated group. After protamine infusion, total body oxygen delivery and consumption correlated negatively with S100beta levels (both p < 0.05) and with NAG levels (both p < 0.01). This study suggests that, if adequate tissue perfusion is not maintained, the use of a heparin coated circuit gives no additional benefit beyond that of the uncoated circuit. The inverse relationship of both cerebral and renal markers with DO2 and VO2 suggests that increased levels of S100beta and NAG during CPB may primarily be caused by an oxygen deficit and secondary to the inflammatory response.

Clinical and technical evaluation of the ACS:OV serum assay and comparison with three other CA125-detecting assays.

BACKGROUND: In this study the clinical and technical performance of the CA125- detecting Bayer ACS:OV immunoluminometric serum assay was compared with three other well-established CA125-detecting assays. METHODS: A total of 1112 serum samples was included in this evaluation: 462 from apparently healthy women, 153 from patients with benign ovarian disease, 163 from patients with malignant ovarian disease, 10 from patients with borderline ovarian malignancies and 78 samples from 12 ovarian cancer patients during monitoring of disease. Serum samples from women with malignant endometrial (n = 68) and colon (n = 32) diseases were also included. Moreover, serum samples from women with benign uterine disease and endometriosis (n = 136) plus 10 serum samples from men (n = 7) and women (n = 3) with human anti-mouse antibodies (HAMA) after immunoscintigraphy were included. All samples were tested in duplicate with the Bayer ACS:OV, the Centocor CA125 II, the Abbott IMx CA125 and the Roche (formerly Boehringer Mannheim) Enzymun-Test CA125 II assays. RESULTS: The clinical performance of the Bayer ACS:OV assay, assessed in various patient groups, was similar to that of the two other automated assays. In serum from patients with benign diseases the highest values were found in patients with benign ovarian tumours. In the ovarian cancer patients followed during the course of disease we found similar marker patterns with all four assays. In contrast to the Roche Enzymun-CA125 II assay and to a lesser extent the Centocor CA125 II assay, the Bayer ACS:OV assay was less sensitive to interference from HAMA. CONCLUSION: The Bayer ACS:OV assay is a precise and reliable test for the quantification of CA125 in serum.

Clinical evaluation of the Elecsys CA 15-3 test in breast cancer patients.

The aim of the present study was to evaluate the clinical performance of the CA 15-3 assay on Elecsys systems in an international multicenter study (11 centers). A total of 1326 single samples (272 apparently healthy individuals, 34 pregnant women, 308 benign diseases, 273 cancers other than breast, 439 breast cancer) and 538 serial samples of 98 breast cancer patients during follow-up were analyzed. 95% of values in healthy individuals were below 25 kU/L, and 88% in benign breast diseases, respectively. In malignant breast disease at primary diagnosis the value distribution of Elecsys CA 15-3, sensitivity at 95% specificity, as well as the areas under the curve in ROC analysis were clearly correlated to tumor stages: UICC I to IV 88 to 25% of values < 25 kU/L, sensitivity 7 to 78%, areas under the curve 0.53 to 0.94. During follow-up, sensitivity/specificity for detection of recurrences were 90%/71%. In metastatic disease clinical progression/response to therapy were indicated in 91%/78% of patients at a specificity of 92%/78%. The findings indicate that the Elecsys CA 15-3 assay is very suitable in routine work for detection of recurrences as well as for therapy control in metastatic breast cancer.

CSF and MRI markers independently contribute to the diagnosis of Alzheimer's disease.

BACKGROUND: Decreased amyloid beta (1-42) (Abeta42) and increased (phosphorylated) tau in cerebrospinal fluid (CSF) are considered to be a reflection of plaques, tangles, and neuronal degeneration in Alzheimer's disease (AD). Atrophy of the medial temporal lobe (MTA) on magnetic resonance imaging (MRI) reflects neuronal loss in this area. OBJECTIVE: To compare diagnostic accuracy of CSF biomarkers and MTA in AD versus controls. METHODS: Abeta42, tau and tau phosphorylated at threonine 181 (Ptau-181) were measured in CSF from 61 AD patients and 32 controls by sandwich enzyme-linked immunosorbent assay. A CSF biomarker profile for AD was constructed. MTA was rated visually on MRI. RESULTS: When AD patients and controls were evaluated separately, no correlations were present between the CSF markers and MTA score. Both MTA and CSF biomarker profile were independently associated with the diagnosis AD (MTA: OR (95% CI)=28 (3-239); CSF biomarker profile: OR (95% CI)=57 (13-262)). Among individuals younger than 65 years old and without MTA 60% suffered AD, and the finding of an abnormal CSF biomarker profile was limited to AD patients only. CONCLUSIONS: MTA and CSF biomarkers seem to be of incremental value for the diagnosis AD. CSF analysis is most sensitive in the absence of MTA, and especially among early-onset AD patients.

Amyloid beta 38, 40, and 42 species in cerebrospinal fluid: more of the same?

Various C-terminally truncated amyloid beta peptides (Abeta) are linked to Alzheimer's disease (AD) pathogenesis. Cerebrospinal fluid (CSF) concentrations of Abeta38, Abeta40, and Abeta42 were measured by enzyme-linked immunosorbent assay in 30 patients with AD and 26 control subjects. CSF Abeta42 levels was decreased in patients with AD, whereas CSF Abeta38 and Abeta40 levels were similar in patients with AD and control subjects. All three Abeta peptides were interrelated, particularly CSF Abeta38 and Abeta40. Diagnostic accuracy of CSF Abeta42 concentrations was not improved by applying the ratios of CSF Abeta42 to Abeta38 or Abeta40.

Effects of processing and storage conditions on amyloid beta (1-42) and tau concentrations in cerebrospinal fluid: implications for use in clinical practice.

BACKGROUND: Reported concentrations of amyloid beta (1-42) (A beta 42) and tau in cerebrospinal fluid (CSF) differ among reports. We investigated the effects of storage temperature, repeated freeze/thaw cycles, and centrifugation on the concentrations of A beta 42 and tau in CSF. METHODS: Stability of samples stored at -80 degrees C was determined by use of an accelerated stability testing protocol according to the Arrhenius equation. A beta 42 and tau concentrations were measured in CSF samples stored at 4, 18, 37, and -80 degrees C. Relative CSF concentrations (%) of the biomarkers after one freeze/thaw cycle were compared with those after two, three, four, five, and six freeze/thaw cycles. In addition, relative A beta 42 and tau concentrations in samples not centrifuged were compared with samples centrifuged after 1, 4, 48, and 72 h. RESULTS: A beta 42 and tau concentrations were stable in CSF when stored for a long period at -80 degrees C. CSF A beta 42 decreased by 20% during the first 2 days at 4, 18, and 37 degrees C compared with -80 degrees C. CSF tau decreased after storage for 12 days at 37 degrees C. After three freeze/thaw cycles, CSF A beta 42 decreased 20%. CSF tau was stable during six freeze/thaw cycles. Centrifugation did not influence the biomarker concentrations. CONCLUSIONS: Repeated freeze/thaw cycles and storage at 4, 18, and 37 degrees C influence the quantitative result of the A beta 42 test. Preferably, samples should be stored at -80 degrees C immediately after collection.

The differential diagnostic potential of a panel of tumor markers (CA 125, CA 15-3, and CA 72-4 antigens) in patients with a pelvic mass.

OBJECTIVE: The purpose of this study was to assess the differential diagnostic potential of a combination of CA 125, CA 15-3, and CA 72-4 antigens in the definition of malignant disease, especially ovarian carcinoma in patients with a pelvic mass. STUDY DESIGN: A total of 412 patients were evaluated in a multicenter, retrospective study. RESULTS: Two hundred twenty-six malignant, 171 benign pelvic tumors (of which 129 were benign ovarian tumors), and 15 borderline tumors were evaluated. One hundred thirty-three patients had ovarian carcinoma. In 76 cases (55%), the International Federation of Gynecology and Obstetrics stage was III or IV. Borderline tumors (n = 15) were excluded from the statistical calculations. CA 125 antigen was the most sensitive marker for ovarian carcinoma (81%). The highest specificity and positive predictive value was obtained with CA 15-3 antigen (95% and 92%, respectively). Considering a concomitant elevation of all 3 markers as positive, a positive predictive value of 97% was found. However, only 28% of the patients in the total group and 41% of the patients with ovarian carcinoma had a concomitant elevation of all 3 markers. The combination of all 3 markers with levels below the cut-off resulted in a (false-positive) positive predictive value for malignancy between 12% and 36%. With the use of logistic regression analysis, we found a correct prediction in 73% of the cases. CA 15-3 antigen makes the most significant (P <.0001) contribution to the logistic model in the prediction of malignancy in the total group, with all pelvic masses with an odds ratio of 3.86. CONCLUSION: The combination of a simultaneous elevated level of CA 125, CA 15-3, and CA 72-4 antigens was predictive for malignant disease in almost all cases. However, such concomitant elevation was found in few of the malignant masses. Logistic regression analysis revealed that CA 15-3 antigen makes the most significant contribution to a model for the prediction of malignancy in the total group. The logistic model gave a correct prediction in 73% to 83%. The present tumor marker panel seems inferior to combinations with other test modalities, which include ultrasonography and/or physical examination and/or menopausal status or age.