In 2010, a tissue‐engineered trachea was transplanted into a 10‐year‐old child using a decellularized deceased donor trachea repopulated with the recipient's respiratory epithelium and mesenchymal ...stromal cells. We report the child's clinical progress, tracheal epithelialization and costs over the 4 years. A chronology of events was derived from clinical notes and costs determined using reference costs per procedure. Serial tracheoscopy images, lung function tests and anti‐HLA blood samples were compared. Epithelial morphology and T cell, Ki67 and cleaved caspase 3 activity were examined. Computational fluid dynamic simulations determined flow, velocity and airway pressure drops. After the first year following transplantation, the number of interventions fell and the child is currently clinically well and continues in education. Endoscopy demonstrated a complete mucosal lining at 15 months, despite retention of a stent. Histocytology indicates a differentiated respiratory layer and no abnormal immune activity. Computational fluid dynamic analysis demonstrated increased velocity and pressure drops around a distal tracheal narrowing. Cross‐sectional area analysis showed restriction of growth within an area of in‐stent stenosis. This report demonstrates the long‐term viability of a decellularized tissue‐engineered trachea within a child. Further research is needed to develop bioengineered pediatric tracheal replacements with lower morbidity, better biomechanics and lower costs.
This case presents a 4‐year follow‐up of a tissue‐engineered pediatric tracheal transplant and reports on the longterm viability of this approach and areas for further research.
During neural tube closure and spinal cord development, many cells die in both the central and peripheral nervous systems (CNS and PNS, respectively). However, myeloid-derived professional phagocytes ...have not yet colonized the trunk region during early neurogenesis. How apoptotic cells are removed from this region during these stages remains largely unknown. Using live imaging in zebrafish, we demonstrate that neural crest cells (NCCs) respond rapidly to dying cells and phagocytose cellular debris around the neural tube. Additionally, NCCs have the ability to enter the CNS through motor exit point transition zones and clear debris in the spinal cord. Surprisingly, NCCs phagocytosis mechanistically resembles macrophage phagocytosis and their recruitment toward cellular debris is mediated by interleukin-1β. Taken together, our results reveal a role for NCCs in phagocytosis of debris in the developing nervous system before the presence of professional phagocytes.
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•Neural crest cells phagocytose debris during early development in the PNS•They migrate into the spinal cord through motor exit points to clear CNS debris•Their recruitment toward debris is mediated by interleukin-1β signaling•Maturation of neural crest phagosomes is similar to that in professional phagocytes
Neural crest cells clear cellular debris left behind from cell death that occurs during early embryonic development, thus revealing an unexpected source of phagocytic activity prior to the arrival of professional phagocytes in the developing zebrafish nervous system.
The surface of healthy cells is composed of lipids that are asymmetrically distributed on the inner and outer leaflet of the plasma membrane. One of these lipids, phosphatidylserine (PS), is normally ...restricted to the inner leaflet of the plasma membrane and is, therefore, only exposed to the cell cytoplasm. However, during apoptosis lipid asymmetry is lost and PS becomes exposed on the outer leaflet of the plasma membrane. Annexin V, a 36-kDa calcium-binding protein, binds to PS; therefore, fluorescently labeled Annexin V can be used to detect PS that is exposed on the outside of apoptotic cells. Annexin V can also stain necrotic cells because these cells have ruptured membranes that permit Annexin V to access the entire plasma membrane. However, apoptotic cells can be distinguished from necrotic cells by co-staining with propidium iodide (PI) because PI enters necrotic cells but is excluded from apoptotic cells. This protocol describes Annexin V binding and PI uptake followed by flow cytometry to detect and quantify apoptotic and necrotic cells.
Apoptosis is orchestrated by caspases, a family of cysteine proteases that cleave their substrates on the carboxy-terminal side of specific aspartic acid residues. These proteases are generally ...present in healthy cells as inactive zymogens, but when stimulated they undergo autolytic cleavage to become fully active. They subsequently cleave their substrates at one or two specific sites, which can result in activation, inactivation, relocalization, or remodeling of the substrate. Consequently, many of the cleaved fragments remain intact during apoptosis and can be detected using substrate-specific antibodies. These fragments are most commonly detected by western blotting, which resolves proteins and their fragments based on molecular mass. However, antibodies that only recognize cleaved fragments can be used to specifically label cells in which caspase cleavage has occurred. It is then possible to quantify these cells by flow cytometry. A number of antibodies that specifically recognize caspase-cleaved fragments have been generated, including antibodies that recognize the cleaved form of caspase-3. This caspase is responsible for the majority of proteolysis during apoptosis, and detection of cleaved caspase-3 is therefore considered a reliable marker for cells that are dying, or have died by apoptosis. This protocol outlines the quantification of apoptosis by flow cytometric detection of cleaved caspase-3.
Feeding neonates orally while on nasal continuous positive airway pressure (nCPAP) is a common practice. We hypothesize that pressurized airflow provided by nCPAP will alter the swallowing mechanism ...in neonates, increasing the risk of aspiration during oral feeding.
Infants receiving nCPAP with a RAM cannula and tolerating at least 50% of their feeding orally were included in the study (one term; six preterm infants). Each participant underwent a videofluoroscopic swallow study while on nCPAP and off nCPAP. A non-parametric signed-rank test was used for paired data.
The incidence of deep penetration (P=0.03) and aspiration (P=0.01) decreased significantly off-nCPAP compared with on-nCPAP. However, the incidence of mild penetration (P=0.65) and nasopharyngeal reflux (P=0.87) remained the same under both conditions.
Oral feeding while on-nCPAP significantly increases the risk of laryngeal penetration and tracheal aspiration events. We recommend caution when initiating oral feedings on nCPAP.
Hemodynamic responses are commonly used to map brain activity; however, their spatial limits have remained unclear because of the lack of a well-defined and malleable spatial stimulus. To examine the ...properties of neural activity and hemodynamic responses, multiunit activity, local field potential, cerebral blood volume (CBV)-sensitive optical imaging, and laser Doppler flowmetry were measured from the somatosensory cortex of transgenic mice expressing Channelrhodopsin-2 in cortex Layer 5 pyramidal neurons. The magnitude and extent of neural and hemodynamic responses were modulated using different photo-stimulation parameters and compared with those induced by somatosensory stimulation. Photo-stimulation-evoked spiking activity across cortical layers was similar to forelimb stimulation, although their activity originated in different layers. Hemodynamic responses induced by forelimb- and photo-stimulation were similar in magnitude and shape, although the former were slightly larger in amplitude and wider in extent. Altogether, the neurovascular relationship differed between these 2 stimulation pathways, but photo-stimulation-evoked changes in neural and hemodynamic activities were linearly correlated. Hemodynamic point spread functions were estimated from the photo-stimulation data and its full-width at half-maximum ranged between 103 and 175 µm. Therefore, submillimeter functional structures separated by a few hundred micrometers may be resolved using hemodynamic methods, such as optical imaging and functional magnetic resonance imaging.
Specific probiotic strains can alleviate the gastrointestinal (GI) symptoms and psychiatric comorbidities of irritable bowel syndrome (IBS). In this randomized, double-blind, placebo-controlled ...study, the efficacy of
HA-196 (
) and
R0175 (
) in reducing the GI and psychological symptoms of IBS was evaluated in 251 adults with either constipation (IBS-C), diarrhea (IBS-D), or mixed-pattern (IBS-M). Following a 2-week run-in period, participants were randomized to one of three interventions:
(
= 84),
(
= 83) or placebo (
= 81). IBS symptoms, stool frequency and consistency and quality of life were assessed by questionnaires. The differences from baseline in the severity of IBS symptoms at 4 and 8 weeks were similar between groups. Participants in this study were classified, after randomization, into subtypes according to Rome III. Within the
group, complete spontaneous and spontaneous bowel movement frequency increased in participants with IBS-C (
= 10) after 8 weeks of supplementation (both
< 0.05) and decreased in participants with IBS-D (
= 10,
= 0.013). Both
and
supplementation improved the quality of life in emotional well-being and social functioning compared with baseline (all
< 0.05). In conclusion,
and
may reduce GI symptom severity and improve the psychological well-being of individuals with certain IBS subtypes.
Early Development of Ocular Dominance Columns Crowley, Justin C.; Katz, Lawrence C.
Science (American Association for the Advancement of Science),
11/2000, Letnik:
290, Številka:
5495
Journal Article
Recenzirano
The segregation of lateral geniculate nucleus (LGN) axons into ocular dominance columns is believed to involve a prolonged, activity-dependent sorting process. However, visualization of early ...postnatal ferret LGN axons by direct LGN tracer injections revealed segregated ocular dominance columns <7 days after innervation of layer 4. These early columns were unaffected by experimentally induced imbalances in retinal activity, implying that different mechanisms govern initial column formation and their modification during the subsequent critical period. Instead of activity-dependent plasticity, we propose that ocular dominance column formation relies on the targeting of distinct axonal populations to defined locales in cortical layer 4.
Results of a prospective randomized trial conducted by the Intergroupe Francais du Myélome (IFM 90) indicated that autologous hematopoietic cell-supported high-dose therapy (HDT) effected higher ...complete response rates and extended progression-free survival (PFS) and overall survival (OS) compared with standard-dose therapies (SDT) for patients with multiple myeloma (MM).
In 1993, three North American cooperative groups launched a prospective randomized trial (S9321) comparing HDT (melphalan MEL 140 mg/m2 plus total-body irradiation 12 Gy) with SDT using the vincristine, carmustine, MEL, cyclophosphamide, and prednisone regimen. Responders on both arms (> or = 75%) were randomly assigned to interferon (IFN) or no maintenance treatment.
With a median follow-up time of 76 months, no differences were observed in response rates between the two study arms (HDT, n = 261 patients; SDT, n = 255 patients). Similarly, PFS and OS durations did not differ between the HDT and SDT arms, with 7-year estimates of PFS of 17% and 16%, respectively, and OS of 37% and 42%, respectively. Of 242 patients achieving at least 75% tumor reduction, no difference was observed in PFS or OS among the 121 patients randomly assigned to IFN and the 121 patients randomly assigned to no maintenance therapy. Among 157 patients relapsing on SDT, 87 received a salvage autotransplantation; their median survival time of 30 months was only slightly better than the survival time of the remaining patients who were managed with further SDT (23 months; P = .13).
The HDT and SDT regimens used in S9321 yielded comparable response rates and PFS and OS durations. IFN maintenance therapy did not benefit patients who achieved > or = 75% tumor reduction on either arm.
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