4 research outputs found
Cochlear erosion due to a facial nerve schwannoma
Facial nerve schwannomas are rare benign neoplasms. We report a case of a 60-year-old woman who initially presented with vestibular complaints. Magnetic resonance imaging (MRI) revealed a facial nerve schwannoma centered on the right geniculate ganglion extending in the labyrinthine segment. The patient consulted again after 2 months because she developed a sudden and severe right-sided sensorineural hearing loss. MRI showed no progression or pathological enhancement in the membranous labyrinth. A cone beam computed tomography (CT) of the temporal bone was performed and revealed a large erosion at the region of the geniculate ganglion in open communication with the middle turn of the cochlea. This case report demonstrates the importance of CT in facial nerve schwannomas for evaluating the impact on the surrounding structures
Molecular toolbox for the identification of unknown genetically modified organisms
Competent laboratories monitor genetically modified
organisms (GMOs) and products derived thereof in the
food and feed chain in the framework of labeling and
traceability legislation. In addition, screening is performed
to detect the unauthorized presence of GMOs including
asynchronously authorized GMOs or GMOs that are not
officially registered for commercialization (unknown
GMOs). Currently, unauthorized or unknown events are
detected by screening blind samples for commonly used
transgenic elements, such as p35S or t-nos. If (1) positive
detection of such screening elements shows the presence of
transgenic material and (2) all known GMOs are tested by
event-specific methods but are not detected, then the
presence of an unknown GMO is inferred. However, such
evidence is indirect because it is based on negative
observations and inconclusive because the procedure does
not identify the causative event per se. In addition,
detection of unknown events is hampered in products that
also contain known authorized events. Here, we outline
alternative approaches for analytical detection and GMO
identification and develop new methods to complement
the existing routine screening procedure. We developed a
fluorescent anchor-polymerase chain reaction (PCR) method
for the identification of the sequences flanking the p35S and
t-nos screening elements. Thus, anchor-PCR fingerprinting
allows the detection of unique discriminative signals per
event. In addition, we established a collection of in silico
calculated fingerprints of known events to support interpretation
of experimentally generated anchor-PCR GM fingerprints
of blind samples. Here, we first describe the molecular
characterization of a novel GMO, which expresses recombinant
human intrinsic factor in Arabidopsis thaliana. Next,
we purposefully treated the novel GMO as a blind sample to
simulate how the new methods lead to the molecular
identification of a novel unknown event without prior
knowledge of its transgene sequence. The results demonstrate
that the new methods complement routine screening procedures
by providing direct conclusive evidence and may also
be useful to resolve masking of unknown events by known
events.
Keywords GMO screening analysis .GMO identification .
Anchor-PCR . Fingerprinting . p35S . t-nosJRC.DDG.I.4-Molecular biology and genomic
Molecular toolbox for the identification of unknown genetically modified organisms
Competent laboratories monitor genetically modified organisms (GMOs) and products derived thereof in the food and feed chain in the framework of labeling and traceability legislation. In addition, screening is performed to detect the unauthorized presence of GMOs including asynchronously authorized GMOs or GMOs that are not officially registered for commercialization (unknown GMOs). Currently, unauthorized or unknown events are detected by screening blind samples for commonly used transgenic elements, such as p35S or t-nos. If (1) positive detection of such screening elements shows the presence of transgenic material and (2) all known GMOs are tested by event-specific methods but are not detected, then the presence of an unknown GMO is inferred. However, such evidence is indirect because it is based on negative observations and inconclusive because the procedure does not identify the causative event per se. In addition, detection of unknown events is hampered in products that also contain known authorized events. Here, we outline alternative approaches for analytical detection and GMO identification and develop new methods to complement the existing routine screening procedure. We developed a fluorescent anchor-polymerase chain reaction (PCR) method for the identification of the sequences flanking the p35S and t-nos screening elements. Thus, anchor-PCR fingerprinting allows the detection of unique discriminative signals per event. In addition, we established a collection of in silico calculated fingerprints of known events to support interpretation of experimentally generated anchor-PCR GM fingerprints of blind samples. Here, we first describe the molecular characterization of a novel GMO, which expresses recombinant human intrinsic factor in Arabidopsis thaliana. Next, we purposefully treated the novel GMO as a blind sample to simulate how the new methods lead to the molecular identification of a novel unknown event without prior knowledge of its transgene sequence. The results demonstrate that the new methods complement routine screening procedures by providing direct conclusive evidence and may also be useful to resolve masking of unknown events by known events