Bundles
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Non-centrosomal microtubule bundles play important roles in cellular organization and function. Although many diverse proteins are known that can bundle microtubules, biochemical mechanisms by which cells could locally control the nucleation and formation of microtubule bundles are understudied. Here, we demonstrate that the concentration of tubulin into a condensed, liquid-like compartment composed of the unstructured neuronal protein tau is sufficient to nucleate microtubule bundles. We show that, under conditions of macro-molecular crowding, tau forms liquid-like drops. Tubulin partitions into these drops, efficiently increasing tubulin concentration and driving the nucleation of microtubules. These growing microtubules form bundles, which deform the drops while remaining enclosed by diffusible tau molecules exhibiting a liquid-like behavior. Our data suggest that condensed compartments of microtubule bundling proteins could promote the local formation of microtubule bundles in neurons by acting as non-centrosomal microtubule nucleation centers and that liquid-like tau encapsulation could provide both stability and plasticity to long axonal microtubule bundles.
- MeSH
- cytoskelet metabolismus MeSH
- FRAP MeSH
- lidé MeSH
- mikrotubuly metabolismus MeSH
- protein - isoformy metabolismus MeSH
- proteiny tau metabolismus MeSH
- tubulin metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVE: To evaluate whether implementing a nutritional care bundle is associated with growth and morbidity in very preterm (VPT) infants. STUDY DESIGN: This study compared 87 VPT infants (<32 gestational weeks) born 2018 (Before group) with 75 infants born 2020 (After group), treated at a single center in the Czech Republic. A nutritional care bundle was implemented during 2019. RESULTS: Median gestational age (weeks) was 30.0 [IQR 27.6-31.1] for the Before group and 29.9 [IQR 27.9-30.6] for the After group. During postnatal days 1-14, parenteral fluid intake was significantly lower in the After group compared to the Before group and conversely for enteral fluid intake. Infants in the After group achieved full enteral feeds by postnatal day 14 (72.9 % vs. Before group 51.9 %). Weight z-scores decreased significantly less from birth to 36 weeks postmenstrual age in the After group (-0.8 [IQR -1.3 to -0.5]) compared to the Before group (-1.5 [IQR -2.0 to -1.2]). Head circumference z-scores decreased significantly less in the After group (-0.8±0.9) than the Before group (-1.6±1.1). Decreased rate of patent ductus arteriosus (PDA) requiring treatment was observed in the After group (P < 0.001). CONCLUSIONS: Implementation of a nutritional care bundle in VPT infants was associated with improved postnatal growth and may reduce treatment-requiring PDA.
Těžká sepse představuje významný celospolečenský problém a je spojena se stoupající incidencí a počtu úmrtí. Léčebné intervence tvořící balíčky péče pro sepsi jsou zaměřeny na zmírnění intenzity systémové propagace prozánětlivého stavu a prevenci vývoje ischemického postižení orgánů vzdálených od ložiska infekce. Balíček péče představuje soubor vědecky nejlépe podložených léčebných intervencí, které, jsou-li použity současně, mají větší šanci na úspěch, než kdyby byly použity samostatně.
Severe sepsis is a major societal problem and is associated with increasing incidence and death counts rise. Therapeutic interventions forming care bundles for sepsis are intended to mitigate the intensity of the proinflammatory state systemic expression and prevent the development of ischemic damage of organs located distantly from the focus of infection. A care bundle represents a collection of the best evidence-based therapeutic interventions, which, when used together, have a greater chance of success than if they were used separately.
- Klíčová slova
- MODS,
- MeSH
- antibakteriální látky škodlivé účinky terapeutické užití MeSH
- hypovolemie diagnóza komplikace terapie MeSH
- klinický obraz nemoci MeSH
- krevní glukóza analýza metabolismus MeSH
- lidé MeSH
- medicína založená na důkazech trendy MeSH
- mikrobiologické techniky metody normy využití MeSH
- multiorgánové selhání diagnóza farmakoterapie komplikace MeSH
- péče o pacienty v kritickém stavu metody normy využití MeSH
- perfuze metody MeSH
- resuscitační péče metody přístrojové vybavení využití MeSH
- sepse diagnóza farmakoterapie komplikace MeSH
- septický šok diagnóza farmakoterapie komplikace MeSH
- směrnice pro lékařskou praxi jako téma MeSH
- syndrom systémové zánětlivé reakce diagnóza farmakoterapie komplikace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Plant vascular meristems are sets of pluripotent cells that enable radial growth by giving rise to vascular tissues and are therefore crucial to plant development. However, the overall dynamics of cellular determination and patterning in and around vascular meristems is still unexplored. We study this process in the shoot vascular tissue of Arabidopsis thaliana, which is organized in vascular bundles that contain three basic cell types (procambium, xylem and phloem). A set of molecules involved in this process has now been identified and partially characterized, but it is not yet clear how the regulatory interactions among them, in conjunction with cellular communication processes, give rise to the steady patterns that accompany cell-fate determination and arrangement within vascular bundles. We put forward a dynamic model factoring in the interactions between molecules (genes, peptides, mRNA and hormones) that have been reported to be central in this process, as well as the relevant communication mechanisms. When a few proposed interactions (unverified, but based on related data) are postulated, the model reproduces the hormonal and molecular patterns expected for the three regions within vascular bundles. In order to test the model, we simulated mutant and hormone-depleted systems and compared the results with experimentally reported phenotypes. The proposed model provides a formal framework integrating a set of growing experimental data and renders a dynamic account of how the collective action of hormones, genes, and other molecules may result in the specification of the three main cell types within shoot vascular bundles. It also offers a tool to test the necessity and sufficiency of particular interactions and conditions for vascular patterning and yields novel predictions that may be experimentally tested. Finally, this model provides a reference for further studies comparing the overall dynamics of tissue organization and formation by meristems in other plant organs and species.
- MeSH
- algoritmy MeSH
- Arabidopsis cytologie genetika metabolismus MeSH
- biologické modely MeSH
- buněčná diferenciace MeSH
- cévní svazky rostlin cytologie genetika metabolismus MeSH
- cytokininy fyziologie MeSH
- genové regulační sítě MeSH
- meristém cytologie genetika metabolismus MeSH
- počítačová simulace MeSH
- proteinkinasy fyziologie MeSH
- proteiny huseníčku fyziologie MeSH
- regulace genové exprese u rostlin MeSH
- signální transdukce MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Kontext: Alternující blokáda levého a pravého raménka Tawarova (raménková blokáda) často "rozostřuje" ischemické změny na elektrokardiogramu. I když se toho o alternující blokádě levého a pravého raménka Tawarova příliš neví, může být pro klinickou praxi významná. Kasuistika: Popisujeme případ muže s potvrzenou blokádou levého Tawarova raménka (left bundle-branch block, LBBB), u něhož při akutním koronárním syndromu došlo k rozvoji blokády pravého Tawarova raménka (right bundle-branch block, RBBB). Koronarogram prokázal subtotální proximální stenózu ramus interventricularis anterior (RIA), která byla řešena implantací stentu. Po perkutánní koronární intervenci došlo k vymizení RBBB a znovuobjevení LBBB. Možným důvodem pro alternující raménkovou blokádu v popisovaném případu je nový zdroj komorových impulsů po počáteční farmakoterapii. Nově vzniklá RBBB je záhadnou klinickou entitou, často spojenou s akutním infarktem myokardu. Blokádu pravého Tawarova raménka lze přidat k infarktu myokardu s elevacemi úseku ST jako rovnocennou indikaci k urgentní reperfuzní léčbě. Proč by si měl být lékař na oddělení urgentního příjmu vědom popsané možnosti? Alternující raménková blokáda může ukazovat na reperfuzi, které vyžaduje změnu léčebného postupu u pacienta s akutním koronárním syndromem.
Case report: We present a case of a patient with a known left bundle-branch block (LBBB) who developed a new right bundle-branch block (RBBB) in a setting of acute coronary syndrome. Coronary angiogram revealed subtotal proximal LAD stenosis that was resolved with stent implantation. After the percutaneous coronary intervention RBBB disappeared and LBBB reappeared. The probable reason for the alternating bundle-branch block in the presented case is a new origin of ventricular impulses after initial medical treat- ment. New onset RBBB has been an intriguing clinical entity often associated with acute myocardial infarction. RBBB could be added to ST-elevation myocardial infarction as an equivalent indication for urgent reperfusion therapy. Why should an emergency physician be aware of this? Alternating bundle-branch block can be an indicator of reperfusion, thus changing the management of an acute coronary syndrome patient.
- MeSH
- akutní koronární syndrom * chirurgie diagnóza MeSH
- blokáda Tawarova raménka * MeSH
- koronární angiografie metody MeSH
- koronární angioplastika metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- výsledek terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
- MeSH
- blokáda Tawarova raménka diagnóza MeSH
- elektrokardiografie metody MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
BACKGROUND: During left bundle branch (LBB) area pacing, it is important to confirm that capture of the LBB, and not just capture of only adjacent left ventricular (LV) myocardium, has been achieved. OBJECTIVE: The purpose of this study was to establish electrocardiographic (ECG) criteria for LBB capture. We hypothesized that because LBB pacing results in physiological depolarization of the LV, then the native QRS can serve as a reference for diagnosis of LBB capture in the same patient. METHODS: Only patients with evidence of LBB capture (QRS morphology transition) were included. Several QRS characteristics were compared between the native rhythm and different types of LBB area capture. RESULTS: A total of 357 ECGs (124 patients) were analyzed: 118 with native rhythm, 124 with nonselective LBB capture, 69 with selective LBB capture, and 46 with LV septal capture. Our hypotheses that during LBB capture the paced V6 R-wave peak time (RWPT; measured from QRS onset) equals the native V6 RWPT and that the paced V6 RWPT (measured from the stimulus) equals the LBB potential to V6 R-wave peak interval were positively validated. Criteria based on these rules had sensitivity and specificity of 88.2%-98.0% and 85.7%-95.4%, respectively. Moreover, 100% specific V6 RWPT cutoff for LBB capture diagnosis in patients with narrow QRS/right bundle branch block was determined to be 74 ms. CONCLUSION: We showed equivalency of LV activation times on ECG during native and paced LBB conduction. Therefore, if V6 RWPT is longer during pacing, this finding is indicative of lack of LBB capture.
- MeSH
- blokáda Tawarova raménka patofyziologie terapie MeSH
- elektrokardiografie metody MeSH
- Hisův svazek fyziologie MeSH
- kardiostimulace umělá metody MeSH
- lidé MeSH
- převodní systém srdeční patofyziologie MeSH
- senioři MeSH
- srdeční frekvence fyziologie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
