Search

Background Medical learners may use YouTube® videos to prepare for procedures. Videos are convenient and readily available, but without any uploading standards, their accuracy and quality for education are uncertain. We assessed the quality of emergency cricothyrotomy videos on YouTube through an expert panel of surgeons with objective quality metrics.Methods A YouTube® search for “emergency cricothyrotomy” was performed and results were filtered to remove animations and lectures. The 4 most-viewed videos were sent to a panel of trauma surgeons for evaluation. An educational quality (EQ) score was generated for each video based on its ability to explain the procedure indications, orient the viewer to the patient, provide accurate narration, provide clear views of procedure, identify relevant instrumentation and anatomy, and explain critical maneuvers. Reviewers were also asked if safety concerns were present and encouraged to give feedback in a free-response field.Results Four surgical attendings completed the survey. The median EQ score was 6 on a 7-point scale (95% CI [6, 6]). All but one of the individual parameters had a median EQ score of 6 (95% CI: indications [3, 7], orientation [5, 7], narration [6, 7], clarity [6, 7], instruments [6, 7], anatomy [6, 6], critical maneuvers [5, 6]). Safety received a lower EQ score (5.5, 95% CI [2, 6]).Conclusions The most-viewed cricothyrotomy videos were rated positively by surgical attendings. Still, it is necessary to know if medical learners can distinguish high from low quality videos. If not, this suggests a need for surgical societies to create high-quality videos that can be reliably and efficiently accessed on YouTube®.

Background Psychiatric illnesses affect outcomes in trauma. Studies have examined the relationship between depression, schizophrenia, post-traumatic stress disorder, and other mental disorders with trauma, yet few have examined attention-deficit-hyperactivity disorder (ADHD). Attention-deficit-hyperactivity disorder has been suggested to increase the risk of injury, but severity and outcomes of the injury are not frequently studied. The relationship of additional psychiatric disorders in patients with ADHD to traumatic injury was also examined in this study.Methods A 5-year retrospective analysis was performed using the trauma registry of an urban ACS verified level 1 trauma center. Patients with ADHD were separated into ADHD Only and ADHD+ (having additional psychiatric comorbidities) and compared to a matched population of non-ADHD patients and patients with non-ADHD psychiatric disorders to analyze their demographics and outcomes. Descriptive statistics were used to analyze the data as appropriate.Results Seventy-three patients with ADHD were identified, with over half having additional psychiatric comorbidities (58.9%). The majority of ADHD patients were White (54.8%) vs Black (61.6%) at admission. At admission non-ADHD patients had significantly fewer psychiatric comorbidities (11%) compared to ADHD patients (58.9%). ADHD with psychiatric comorbidities patients had significantly higher ISS and longer hospital LOS. However, GCS and ICU LOS were not different between the two groups.Conclusions Patients with ADHD were significantly more likely to have psychiatric comorbidities and experience worse outcomes compared to patients without ADHD.

Platelet-activating factor (1-o-alkyl-2-acetyl-sn-gylcero-3-phosphocholine [PAF]) is one of several autocrine trophic factors supporting the development of the preimplantation embryo. PAF acts on the embryo to induce receptor-mediated intracellular calcium (Ca2+)itransients, and these coincide with a marked membrane hyperpolarization. Patch-clamp analysis of 2-cell embryos showed that these Ca2+itransients resulted in an outward membrane current. The present study characterizes this current and assesses its role in embryo development. The outward current was dependent upon the presence of anions in the extracellular medium and occurred as a consequence of the PAF-induced Ca2+itransients. The anion current induced by PAF was inhibited by niflumic acid (NFA), a selective blocker of Ca2+-activated Cl–channels, but this drug did not block the PAF-induced Ca2+itransients. Voltage ramp analysis showed that the Cl–conductance was outwardly rectifying and inactivated at holding potentials more positive than +30 mV. Culture in NFA or 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (a broad-specificity anion channel blocker) from the zygote stage significantly reduced development to blastocysts, with most arresting at the 4-cell and 8-cell stages. Niflumic acid exposure only from the zygote to the late 2-cell stage also reduced the subsequent development to blastocysts. By contrast, treatment from the late 2-cell stage or the 8-cell stage had no effect on development to the blastocyst stage. This study demonstrates the activation of a Ca2+-sensitive Cl–channel in the 2-cell embryo by PAF and shows that this current activity during the zygote to 2-cell stage is required for normal embryo development in vitro.

Paf (1-o-alkyl-2-acetyl-sn-gylcero-3-phosphocholine) is a putative autocrine survival factor for the preimplantation embryo. It acts to induce receptor-mediated calcium transients in the early embryo. Inhibitors of 1-o-phosphatidylinositol-3-kinase (PI3kinase), such as wortmannin and LY 294002, blocked these calcium transients, implicating the generation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3) in autocrine signal transduction in the early embryo. Perfusion of the embryo cytoplasm with a blocking antibody to PIP3 inhibited paf-induced calcium transients and hyperpolarization of the membrane potential. Furthermore, direct infusion of PIP3 into the embryo induced a nifedipine (10 μmol/L)- and diltiazem (10 μmol/L)-sensitive calcium current in the 2-cell embryo. PIP3 acts as a docking site on membranes for proteins that contain pleckstrin homology domains, such as the thymoma viral proto-oncogene protein (AKT) and phospholipase C gamma. The 2-cell embryo expressed three genes for AKT (Akt 1–3) and two genes for phospholipase C gamma (Plcg1and Plcg2), and we confirmed the expression of both AKT and phospholipase C gamma 1 by immunolocalization. Paf induced increased accumulation of serine 473-phosphorylated AKT in the region of the plasma membrane, consistent with its recruitment to membrane PIP3. Inhibitors of PI3kinase, such as LY294002, and of AKT, e.g., deguelin and AKT-inhibitor, reduced zygote development in a dose-dependent manner, and this inhibition was partially reversed by the addition of paf to the culture medium. These results provide the first direct evidence that PIP3 and its responsive signaling pathways act in the 2-cell embryo. Since signal transduction via PI3kinase has important roles in governing the cell survival pathways, these results support the hypothesis that autocrine embryotropins, such as paf, act as survival factors.

Platelet-activating factor (PAF) is an autocrine trophic/survival factor for the preimplantation embryo. PAF induced an increase in intracellular calcium concentration ([Ca2+]i) in the 2-cell embryo that had an absolute requirement for external calcium. L-type calcium channel blockers (diltiazem, verapamil, and nimodipine) significantly inhibited PAF-induced Ca2+transients, but inhibitors of P/Q type (ω-agatoxin; ω-conotoxin MVIIC), N-type (ω-conotoxin GVIA), T-type (pimozide), and store-operated channels (SKF 96365 and econazole) did not block the transient. mRNA and protein for the α1-Csubunit of L-type channels was expressed in the 2-cell embryo. The L-type calcium channel agonist (±) BAY K 8644 induced [Ca2+]itransients and, PAF and BAY K 8644 each caused mutual heterologous desensitization of each other’s responses. Depolarization of the embryo (75 mM KCl) induced a [Ca2+]itransient that was inhibited by diltiazem and verapamil. Whole-cell patch-clamp measurements detected a voltage-gated channel (blocked by diltiazem, verapamil, and nifedipine) that was desensitized by prior responses of embryos to exogenous or embryo-derived PAF. Replacement of media Ca2+with Mn2+allowed Mn2+influx to be observed directly; activation of a diltiazem-sensitive influx channel was an early response to PAF. The activation of a voltage-gated L-type calcium channel in the 2-cell embryo is required for normal signal transduction to an embryonic trophic factor.

During embryogenesis cells make appropriately timed developmental decisions. Both ‘hourglass-like’ and ‘clock-like’ mechanisms have been demonstrated to act as timers in early development. The cell cycle rhythm, using feedback circuits to drive cells unidirectionally through checkpoints, is an example of a clock-like timer, but how it operates to time developmental events is unclear. In other cell types, cyclic oscillations in K+ channel activity, which parallel cell cycle and circadian rhythms, may be part of the timing mechanism. Changes in K+ oscillations accompany key developmental transitions and oncogenic transformation. Channel blockade interferes pharmaco-logically with cell cycle initiation or progression, whereas channel over-expression can be oncogenic. K+ channel activity also exists in early mouse oocytes through to at least the blastocyst stage, and it oscillates in phase with the developmental cell cycles, being high in M/G1 and low in S/G2. It resembles physiologically the activity of the K+ channels of the eag- or erg-like families. Reverse transcriptase–polymerase chain reaction of mouse oocytes has revealed the presence of transcripts encoding both EAG- and ERG-like proteins throughout preimplantation devel-opment. Channel activity continues to oscillate with a cell cycle periodicity in embryos from which the nucleus has been removed, or after inhibition by puromycin of the cyclin B–cyclin-dependent kinase 1 driven component of the chromosomal cycle. Channel oscillatory activity thus appears to be able to function autonomously of the chromo-somal cycle and may represent a distinct oscillatory timing activity with possible developmental significance. Extra keywords: cyclins, developmental timer, EAG, ERG, K+ channel, mouse embryo.

The luminal epithelium lining the uterus is an essential component in blastocyst implantation. This layer of epithelial cells forms a barrier which in the nonreceptive state, is impenetrable to invasion by the embryonic trophoblast cells. As such, maintenance or disassembly of the lateral adhesions between these cells is an important determinant in the events of endometrial receptivity and blastocyst penetration into the underlying stroma. The Epithelial Cell Adhesion Molecule (EpCAM) represents a homophilic Ca2+-independent cell adhesion molecule which is abundantly expressed in various epithelial tissues as a 40kDa protein. In normal epithelia, EpCAM has been demonstrated to mediate weak intercellular adhesions (compared with those mediated by E-cadherin) through interaction with the actin cytoskeleton. Thus this study sought to investigate the presence and localisation of EpCAM in the maternal endometrium of the rat during early pregnancy and furthermore whether this protein was under hormonal control. It was demonstrated through immunofluorescence and western blotting that during early pregnancy (days 1-9) in the rat, the EpCAM protein localises to the basolateral membrane of the uterine luminal and glandular epithelium. However, at the time of and after implantation (days 6-9 in the rat), levels of the 40kDa protein decrease. Ovariectomy studies further demonstrate that this decrease in EpCAM protein levels requires both progesterone with estrogen. We suggest that prior to implantation; EpCAM may function to strengthen the strong adhesions mediated by E-cadherin. At the time of implantation, we propose that while reduced EpCAM is sufficiently present to facilitate weak adhesions which serve two purposes: to maintain an intact epithelial barrier protecting the underlying stroma (such as against pathogenic attack) and also to form adhesions that can be degraded by the blastocyst invasion.(poster)

Adhesion to extracellular matrix is mediated primarily by integrins, which cluster with other proteins at focal adhesions. Caveolin has also been reported to be linked with integrins. At the time of implantation integrins β1 and β3 disassemble from basal focal adhesions with integrin β3 becoming apically localised in rat uterine epithelial cells and also in Ishikawa cells, a model cell line for a receptive endometrium. Paxillin and talin are two proteins that are essential components of the focal adhesion complex. Both paxillin and talin are lost basally in rat luminal epithelial cells at the time of implantation, indicating their importance in the loss of focal adhesions at this time. The present study investigated the localisation of caveolin 1 and 2 in rat uterine epithelial cells during early pregnancy, and also paxillin and talin in human Ishikawa cells, to determine their role in focal adhesion dynamics. Caveolin 1 and 2 in rat uterine epithelial cells during early pregnancy are cytoplasmic on day 1 and become increasingly basal at the time of implantation. At this time there is a statistically significant increase in caveolin 1 protein expression, while caveolin 2 is reduced. Ovariectomised rats treated with different hormonal regimes indicated that the basal localisation of caveolin 1 and 2 in luminal uterine epithelia is dependent on progesterone. Confocal immunofluorescence microscopy of Ishikawa cells grown on glass coverslips coated with matrigel showed that caveolins 1 and 2, talin and paxillin are localised apically in Ishikawa cells when provided with an extracellular matrix. This is in contrast to the absence of these proteins in Ishikawa cells when grown directly on glass. Hence it appears that the presence of an extracellular matrix is important for the expression of talin, paxillin and caveolin. Hormonal treatment of Ishikawa cells did not however alter the localisation of caveolins 1 and 2 or paxillin and talin. The present results suggest that at the time of implantation, caveolin in rat luminal uterine epithelial cells may have possible roles in trafficking of various proteins for either degradation or relocation such as those found in focal adhesions, namely talin, paxillin and potentially integrins, which may play a role during successful blastocyst implantation. This is supported by the observation that caveolin, talin and paxillin are apically localised in Ishikawa cells.(poster)

Receptivity of the uterine luminal epithelium to blastocyst penetration is an important determinant of pregnancy success and the glycocalyx of the uterine luminal epithelium forms the first point of contact between the uterus and blastocyst. A family of proteins called Mucins are a major component of the glycocalyx and a few (Mucins 1, 4 and 16) provide an anti-adhesive surface on the uterine luminal epithelial surface through the mechanism of "steric hindrance." The presence of one of them (Mucin 1) is proven to inhibit implantation. Given their important role, this study sought to elucidate a functional role for other members of the Mucin family, specifically Mucins 13 and 15. Immunofluorescence, western blotting and ovariectomy studies were utilised to examine the localisation and expression of Mucins 13 and 15 in the uterus during early pregnancy and the pre-implantation blastocyst and determine whether the proteins are hormonally regulated in the uterus. Immunofluorescence studies show that Mucin 13 is present apically in uterine luminal epithelial cells at time of implantation while Mucin 15 is lost from the cell surface at implantation. Both proteins are present in the blastocyst and localise to the trophoblast cells and inner cell mass. However, Mucin 15 is additionally present in the zona pellucida of the blastocyst, an anti-adhesive structure which prevents attachment of the blastocyst outside the uterine chamber. Western blotting results support these immunofluorescence findings and further demonstrate that these proteins may undergo changes to their glycosylation profiles which have implications for their functions. Ovariectomy studies demonstrate that Mucin 13 is upregulated to the apical cell surface by progesterone while Mucin 15 is hormonally upregulated by estrogen. Collectively, this study suggests that Mucins 13 and 15 are hormonally regulated in the uterus and play contrasting roles in the implantation event, with Mucin 13 contributing to an adhesive surface to facilitate attachment of the blastocyst to the uterine luminal epithelium. Conversely, Mucin 15 appears to form an anti-adhesive molecule and its absence may allow implantation to occur. These findings suggest that different Mucins have differing and opposing roles in the uterus and blastocyst.(poster)

Successful blastocyst implantation requires extensive alteration of uterine epithelial cells (UECs) followed by their removal in order for the implanting blastocyst to penetrate into the underlying endometrium. The dynamics of focal adhesions (FAs) may play a role during this process because FAs are specialised structural complexes that provide adhesion between the cell and its underlying basal lamina. The present study investigated the expression and distribution of FA proteins in rat UECs at the time of implantation and their hormonal control as well as their expression in blastocyst stage embryos. Immunofluorescence microscopy showed that the principal focal adhesion proteins, talin and paxillin, were localised along the basal cell surface of UECs on day 1 of pregnancy and significantly reduced from the site of FAs at the time of implantation allowing the UECs to become less adhesive to the underling basal lamina. This is thought to be a critical process in the removal of UECs, which enables the invasion of the implanting blastocyst into the underlying decidual cells. Ovariectomised rats treated under various hormone regimes showed that talin and paxillin were tightly regulated by ovarian hormones in UECs. In particular, FA disassembly seen at the time implantation was predominantly under the control of progesterone. FA dynamics are regulated by the clustering of specific integrin subunits and immunofluorescence microscopy and immunoprecipitation have shown that integrinβ1 and β3 subunits colocalise and interact with talin at the site of FAs on day 1 of pregnancy. Integrin β1 and β3 were markedly reduced from the site of FAs at the time of implantation. However unlike the other FA proteins, localisation of integrin β3 on the apical membrane of UECs increased significantly at this time with a corresponding increase of integrin β3 expression in the membrane shown by subcellular fractionation. Like talin and paxillin, the distributional change of integrin β1 and β3 in the UECs at the time of implantation were also under the control of progesterone. Immunofluorescence microscopy have shown that in the rat blastocyst, integrin β3 was concentrated around the nuclei and was not present in the inner cell mass and integrin β1 weakly stained in the cytoplasm of the trophoblast cells. Interestingly, another FA protein, FAK was not present at the site of FAs in the UECs during early pregnancy. Instead, FAK colocalised with a tight junctional marker ZO-1 on day 1 of pregnancy and increased in the apical portion of the UECs at the time of implantation, suggesting a possible role of FAK in regulating tight junctional structures. FAK in the rat blastocyst was present in the apical membrane and did not colocalise with a tight junctional marker occludin, suggesting that FAK has a different role in the rat uterus and the blastocyst. Taken together, our results show that disassembly of FA proteins play an integral part in the removal of UECs in order to establish successful implantation and is tightly regulated by ovarian hormones.(platform)

The uterine epithelium undergoes extensive molecular changes during early pregnancy to become receptive to an implanting embryo, and this is tightly regulated by ovarian hormones. Many adhesion molecules are known to reorganize during early pregnancy in order to facilitate embryo adhesion to the apical membrane of uterine epithelial cells and play an important role in uterine receptivity. This study examined the changes in distribution, expression and hormonal control of ICAM-1 in the rat uterus during early pregnancy, in ovariectomised rats, pseudo pregnant rats and cultured preimplantation embryos. The use of ICAM-1 specific vivo-morpholino antisense oligonucleotides was employed to discover the role of ICAM-1 in embryo development and implantation. ICAM-1 was visualized in the rat uterus using indirect immunofluorescence microscopy and was absent in the uterine epithelium on day 1 (pre-receptive) and day 3 of pregnancy. By day 6 (receptive) and day 7 of pregnancy at the time of implantation in the rat, ICAM-1 is present in the uterine epithelium and is localized to the apical region. ICAM-1 then disappears in uterine epithelial cells by day 9 (post receptive) of pregnancy. ICAM-1 thus is likely an important molecule in the adhesion of an implanting embryo to the apical membrane of uterine epithelial cells in rats. ICAM-1 is absent in the uterine epithelium of ovariectomised rats treated with oestrogen alone (non-receptive) and apical in the uterine epithelium of rats treated with progesterone alone, or combined with estrogen (receptive); and was apical in day 6 pseudo pregnant animals. Apical ICAM-1 staining in the uterine epithelium, on day 6 of pregnancy and in ovariectomised rats treated with progesterone and in pseudo pregnant rats always coincides with an increase in ICAM-1 monomeric expression on western blots. Dimeric expression of ICAM-1 did not alter from day 1 to day 6 of pregnancy and corresponds to the ICAM-1 protein found in endothelium. ICAM-1 was however present in endothelial cells of blood vessels found in the endometrial stroma at all stages of pregnancy. This indicates that ICAM-1 in uterine epithelial cells is under progesterone control and that endothelial ICAM-1 is not at all influenced by ovarian hormones. Previous studies have suggested that ICAM-1 might be up regulated by cytokines released by implanting embryos; however the use of pseudo pregnant and ovariectomised rats has shown that this is not the case. ICAM-1 is also present in pre-implantation embryos and may be necessary in facilitating embryo adhesion. Moreover, early day 3 embryos exposed to ICAM-1 vivo-morpholino antisense oligonucleotides fail to develop into blastocysts. In summary ICAM-1 is likely an important molecule in the receptivity of uterine epithelial cells and is under progesterone control. ICAM-1 is also a necessary molecule in embryo development.(platform)

Platelet activating factor (paf) is an autocrine survival factor that acts on the preimplantation embryo from the late zygote stage through to the end of the 2-cell stage. Binding of paf to its receptor activates PI3kinase, causing an IP3-dependent release of Ca2+from intracellular stores as well as activation of Ca2+influx via a dihydropyridine-sensitive Ca2+channel. These actions result in the generation of a defined intracellular calcium ([Ca2+]i) transient that recurs with a periodicity of approximately 60-90 min. By using combined whole-cell patch-clamp and real-time [Ca2+]ianalyses, we have shown that paf also induces a concomitant hyperpolarization of the membrane potential in 2-cell embryos, accompanied by an increased outward ion current. Both the membrane hyperpolarization and outward current were dependent upon the occurrence of the paf-induced [Ca2+]itransient. The aim of this study was to examine the role of the outward current in generating the transient hyperpolarization of the embryos plasma membrane, and to assess whether the current plays a role in normal mouse preimplantation development. We show that removal of extracellular anions prevented activation of the outward current by paf but had no effect on the paf-induced [Ca2+]itransient. This data suggests that the outward current resulted from activation of a Ca2+-activated Cl-channel. Niflumic acid (NFA, 100 μM), an inhibitor of Ca2+-activated Cl-channels, had no effect on the paf-induced [Ca2+]i, response but significantly reduced the amplitude of the hyperpolarization of membrane potential (p < 0.05) and the outward current (p < 0.01). In order to assess whether the outward Cl-current has a role in paf-induced embryo survival, the effect of NFA on embryo development was examined. The culture of embryos in medium containing 100 μM NFA from the 1-cell stage significantly reduced their development to the 4-cell stage (p < 0.05). By contrast, culture in medium containing NFA from the 8-cell stage had no effect on their development to the blastocyst stage. The results show that paf induces an increase in [Ca2+]iwhich in turn activates a Ca2+-activated Cl-channel. This channel is sensitive to NFA, and exposure of the zygote and 2-cell embryo to NFA blocked normal embryo development. Activation of a NFA-sensitive Cl-channel by a trophic ligand(s) during early development is required for the normal development of the mouse preimplantation embryo.