12 research outputs found
Clinical utility of chromogranin A and octreotide in large cell neuro endocrine carcinoma of the uterine corpus
Primary neuroendocrine tumors of the female genital tract have been described in the cervix, ovaries and uterus. Large cell neuroendocrine carcinoma (LCNC) of the uterine corpus is the least common and appears to behave the most aggressively. We report a rare case of a large cell neuroendocrine tumor of the endometrium. These tumors are not well characterized, unlike neuroendocrine tumors of the uterine cervix. Consequently, the optimal management remains still unclear. The treatment of our case consisted of surgery, radiotherapy, chemotherapy, and octreotide. Despite the aggressive treatment, the patient died of disease progression 12 months after the initial diagnosis. We discuss the diagnosis, prognosis, and treatment options for LCNC of the genital tract, and potential future therapeutics
Rapid Acquisition of X-Ray Scattering Data from Droplet-Encapsulated Protein Systems
Encapsulating reacting biological or chemical samples in microfluidic droplets has the great advantage over single-phase flows of providing separate reaction compartments. These compartments can be filled in a combinatoric way and prevent the sample from adsorbing to the channel walls. In recent years, small-angle X-ray scattering (SAXS) in combination with microfluidics has evolved as a nanoscale method of such systems. Here, we approach two major challenges associated with combining droplet microfluidics and SAXS. First, we present a simple, versatile, and reliable device, which is both suitable for stable droplet formation and compatible with in situ X-ray measurements. Second, we solve the problem of âdilutingâ the sample signal by the signal from the oil separating the emulsion droplets by multiple fast acquisitions per droplet and data thresholding. We show that using our method, even the weakly scattering protein vimentin provides high signal-to-noise ratio data
Xârays Reveal the Internal Structure of Keratin Bundles in Whole Cells
In recent years, X-ray imaging of
biological cells has emerged
as a complementary alternative to fluorescence and electron microscopy.
Different techniques were established and successfully applied to
macromolecular assemblies and structures in cells. However, while
the resolution is reaching the nanometer scale, the dose is increasing.
It is essential to develop strategies to overcome or reduce radiation
damage. Here we approach this intrinsic problem by combing two different
X-ray techniques, namely ptychography and nanodiffraction, in one
experiment and on the same sample. We acquire low dose ptychography
overview images of whole cells at a resolution of 65 nm. We subsequently
record high-resolution nanodiffraction data from regions of interest.
By comparing images from the two modalities, we can exclude strong
effects of radiation damage on the specimen. From the diffraction
data we retrieve quantitative structural information from intracellular
bundles of keratin intermediate filaments such as a filament radius
of 5 nm, hexagonal geometric arrangement with an interfilament distance
of 14 nm and bundle diameters on the order of 70 nm. Thus, we present
an appealing combined approach to answer a broad range of questions
in soft-matter physics, biophysics and biology
Following DNA Compaction During the Cell Cycle by Xâray Nanodiffraction
X-ray
imaging of intact biological cells is emerging as a complementary
method to visible light or electron microscopy. Owing to the high
penetration depth and small wavelength of X-rays, it is possible to
resolve subcellular structures at a resolution of a few nanometers.
Here, we apply scanning X-ray nanodiffraction in combination with
time-lapse bright-field microscopy to nuclei of 3T3 fibroblasts and
thus relate the observed structures to specific phases in the cell
division cycle. We scan the sample at a step size of 250 nm and analyze
the individual diffraction patterns according to a generalized Porodâs
law. Thus, we obtain information on the aggregation state of the nuclear
DNA at a real space resolution on the order of the step size and in
parallel structural information on the order of few nanometers. We
are able to distinguish nucleoli, heterochromatin, and euchromatin
in the nuclei and follow the compaction and decompaction during the
cell division cycle
Tropomyosin variants describe distinct functional subcellular domains in differentiated vascular smooth muscle cells
Tropomyosin (Tm) is known to be an important gatekeeper of actin function. Tm isoforms are encoded by four genes, and each gene produces several variants by alternative splicing, which have been proposed to play roles in motility, proliferation, and apoptosis. Smooth muscle studies have focused on gizzard smooth muscle, where a heterodimer of Tm from the α-gene (Tmsm-α) and from the ÎČ-gene (Tmsm-ÎČ) is associated with contractile filaments. In this study we examined Tm in differentiated mammalian vascular smooth muscle (dVSM). Liquid chromatography-tandem mass spectrometry (LC MS/MS) analysis and Western blot screening with variant-specific antibodies revealed that at least five different Tm proteins are expressed in this tissue: Tm6 (Tmsm-α) and Tm2 from the α-gene, Tm1 (Tmsm-ÎČ) from the ÎČ-gene, Tm5NM1 from the Îł-gene, and Tm4 from the ÎŽ-gene. Tm6 is by far most abundant in dVSM followed by Tm1, Tm2, Tm5NM1, and Tm4. Coimmunoprecipitation and coimmunofluorescence studies demonstrate that Tm1 and Tm6 coassociate with different actin isoforms and display different intracellular localizations. Using an antibody specific for cytoplasmic Îł-actin, we report here the presence of a Îł-actin cortical cytoskeleton in dVSM cells. Tm1 colocalizes with cortical cytoplasmic Îł-actin and coprecipitates with Îł-actin. Tm6, on the other hand, is located on contractile bundles. These data indicate that Tm1 and Tm6 do not form a classical heterodimer in dVSM but rather describe different functional cellular compartments
Les Ăcoles dans la guerre
L'Ăcole nâest pas hors du monde et hors du temps. Lorsque les « malheurs de la guerre » frappent un territoire et ses habitants, les acteurs Ă©ducatifs et les structures scolaires sont touchĂ©s. La mobilisation des hommes pour le combat atteint les personnels et les plus grands Ă©lĂšves ainsi que les Ă©tudiants, qui dĂ©laissent la plume et le verbe pour lâĂ©pĂ©e et le fusil. Ă lâarriĂšre, les acteurs de lâĂcole tentent de maintenir en vie les structures scolaires et universitaires et de les mobiliser pour la victoire alors que nombre de bĂątiments sont aussi rĂ©quisitionnĂ©s pour dâautres missions. Lorsque la guerre, devenue dĂ©faite temporaire ou plus durable, dĂ©bouche sur lâoccupation par des forces ennemies ou sur lâinstallation dâun nouveau rĂ©gime politique (tel le RĂ©gime de Vichy), les Ăcoles doivent apprendre à « survivre » en terrain hostile, marquant souvent par leur prĂ©sence une forme de rĂ©sistance. Le positionnement des acteurs Ă©ducatifs, dans ces pĂ©riodes « noires » sâavĂšre complexe. LâĂcole, qui peut ĂȘtre un outil de formation au service de lâesprit raisonnable et de la paix entre les hommes, peut aussi, sous certaines conditions, devenir un instrument au service de la prĂ©paration de la guerre. Ce sont lĂ les thĂ©matiques majeures proposĂ©es par ce livre qui, autour de 24 contributions inĂ©dites, croisant les Ă©chelles spatiales, fait aussi le choix de la longue durĂ©e (xviie-xxe siĂšcles), mĂȘme si elles portent surtout sur les deux guerres mondiales du xxe siĂšcle