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  • Articles  (4)
  • Munksgaard International Publishers  (2)
  • German Medical Science; Düsseldorf, Köln  (1)
  • The American Association for Clinical Chemistry (AACC)  (1)
  • 1
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    German Medical Science; Düsseldorf, Köln
    In:  51. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie; 20060910-20060914; Leipzig; DOC06gmds056 /20060901/
    Publication Date: 2006-09-25
    Keywords: ddc: 610
    Language: German
    Type: conferenceObject
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  • 2
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: To investigate whether free melatonin may be better suited to reveal age-related changes, we studied the circadian rhythm alterations in saliva melatonin levels during aging. Special attention was paid to the question as to how the free melatonin rhythms change in aging and when such changes take place. A total of 52 healthy volunteers participated in the study consisting of young, middle-aged, old and the oldest groups. In each subject, a total of 12 time-point salivary melatonin samples was taken over 24 hr. Of the 52 data sets, 51 exhibited significant circadian rhythm over 24 hr by using the base cosine function analysis to fit the data. A clear circadian rhythm of salivary melatonin was present in all age groups. The decline in nocturnal peak levels (amplitude) in salivary melatonin was found in old and the oldest subjects. Both the old and the oldest subjects showed an increased daytime (baseline) melatonin levels. The off-set melatonin levels were more than two times higher in the oldest group than that in the other groups indicating a delayed phase of salivary melatonin. Most strikingly, we found that a step-wise decrease in the circadian rhythms of saliva melatonin occurred early in life, around 40 yr of ages. The middle-aged subjects had only 60% of the amplitude of the young subjects. In addition, the middle-aged subjects showed the longest peak levels duration and the lowest daytime melatonin levels. The present study showed that the alterations in the circadian rhythms of salivary melatonin begin during middle-age. Our results showed that salivary melatonin measurement is a reliable, sensitive and easy method to monitor changes in the circadian rhythms of melatonin during the course of aging.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Neuropathology is the most reliable criterion for diagnosing Alzheimer's disease (AD). A well-established system for staging the spread of neuropathological changes in AD is available. The clinical use of a biomarker that reflects the neuropathological change occurring in brain tissue has not yet been established. Melatonin is a product that plays not only a major role in the regulation of the circadian rhythms but may also exert neuroprotective effects in AD. Melatonin levels were determined in ventricular postmortem cerebrospinal fluid (CSF) of 121 subjects. Braak staging and a modified Braak staging for cortex (MBSC) were used to evaluate the severity of AD neuropathology. The present study revealed that not only the Braak stages of AD, but also the MBSC were negatively correlated with CSF melatonin levels. By using MBSC, we now demonstrate for the first time that CSF melatonin levels were significantly decreased in the aged individuals with early neuropathological changes in the temporal cortex, where the AD process starts. Those individuals that did not have any neurofibrillary tangle (NFT) or neuritic plaque (NP) in the temporal cortex, had much higher melatonin levels (287 ± 68 and 280 ± 64 pg/mL, respectively) than those individuals that had a few NFTs and NPs (82 ± 4 and 39 ± 8 pg/mL, respectively) in the temporal cortex. These results suggest that the decrease in CSF melatonin levels may be an early event in the development of AD possibly occurring even before the clinical symptoms.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2018-01-30
    Description: BACKGROUND: Progress in the liquid biopsy field, combined with the development of droplet digital PCR (ddPCR), has enabled noninvasive monitoring of mutations with high detection accuracy. However, current assays detect a restricted number of mutations per reaction. ddPCR is a recognized method for detecting alterations previously characterized in tumor tissues, but its use as a discovery tool when the mutation is unknown a priori remains limited. METHODS: We established 2 ddPCR assays detecting all genomic alterations within KRAS exon 2 and EGFR exon 19 mutation hotspots, which are of clinical importance in colorectal and lung cancer, with use of a unique pair of TaqMan ® oligoprobes. The KRAS assay scanned for the 7 most common mutations in codons 12/13 but also all other mutations found in that region. The EGFR assay screened for all in-frame deletions of exon 19, which are frequent EGFR-activating events. RESULTS: The KRAS and EGFR assays were highly specific and both reached a limit of detection of 〈0.1% in mutant allele frequency. We further validated their performance on multiple plasma and formalin-fixed and paraffin-embedded tumor samples harboring a panel of different KRAS or EGFR mutations. CONCLUSIONS: This method presents the advantage of detecting a higher number of mutations with single-reaction ddPCRs while consuming a minimum of patient sample. This is particularly useful in the context of liquid biopsy because the amount of circulating tumor DNA is often low. This method should be useful as a discovery tool when the tumor tissue is unavailable or to monitor disease during therapy.
    Keywords: Cancer Diagnostics (since 2002)
    Print ISSN: 0009-9147
    Electronic ISSN: 1530-8561
    Topics: Medicine
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