Auxins and cytokinins : the role of subcellular organization on homeostasis

Plant hormones are master regulators of plant growth and development. Better knowledge of their spatial signaling and homeostasis (transport and metabolism) on the lowest structural levels (cellular and subcellular) is therefore crucial to a better understanding of developmental processes in plants. Recent progress in phytohormone analysis at the cellular and subcellular levels has greatly improved the effectiveness of isolation protocols and the sensitivity of analytical methods. This review is mainly focused on homeostasis of two plant hormone groups, auxins and cytokinins. It will summarize and discuss their tissue- and cell-type specific distributions at the cellular and subcellular levels

Role of P-selectin in platelet sequestration in pulmonary capillaries during endotoxemia

Background: There is growing evidence that platelets accumulate in the lung and contribute to the pathogenesis of acute lung injury during endotoxemia. The aims of the present study were to localize platelet sequestration in the pulmonary microcirculation and to investigate the role of P-selectin as a molecular mechanism of platelet endothelial cell interaction. Methods: We used in vivo fluorescence microscopy to quantify the kinetics of fluorescently labeled erythrocytes and platelets in alveolar capillary networks in rabbit lungs. Results: Six hours after onset of endotoxin infusion we observed a massive rolling along and firm adherence of platelets to lung capillary endothelial cells whereas under control conditions no platelet sequestration was detected. P-selectin was expressed on the surface of separated platelets which were incubated with endotoxin and in lung tissue. Pretreatment of platelets with fucoidin, a P-selectin antagonist, significantly attenuated the endotoxin-induced platelet rolling and adherence. In contrast, intravenous infusion of fucoidin in endotoxin-treated rabbits did not inhibit platelet sequestration in pulmonary capillaries. Conclusion: We conclude that platelets accumulate in alveolar capillaries following endotoxemia. P-selectin expressed on the surface of platelets seems to play an important role in mediating this platelet-endothelial cell interaction. Copyright (c) 2006 S. Karger AG, Basel

The Mast Cell Degranulator Compound 48/80 Directly Activates Neurons

Background Compound 48/80 is widely used in animal and tissue models as a “selective” mast cell activator. With this study we demonstrate that compound 48/80 also directly activates enteric neurons and visceral afferents. Methodology/Principal Findings We used in vivo recordings from extrinsic intestinal afferents together with Ca++ imaging from primary cultures of DRG and nodose neurons. Enteric neuronal activation was examined by Ca++ and voltage sensitive dye imaging in isolated gut preparations and primary cultures of enteric neurons. Intraluminal application of compound 48/80 evoked marked afferent firing which desensitized on subsequent administration. In egg albumen-sensitized animals, intraluminal antigen evoked a similar pattern of afferent activation which also desensitized on subsequent exposure to antigen. In cross-desensitization experiments prior administration of compound 48/80 failed to influence the mast cell mediated response. Application of 1 and 10 µg/ml compound 48/80 evoked spike discharge and Ca++ transients in enteric neurons. The same nerve activating effect was observed in primary cultures of DRG and nodose ganglion cells. Enteric neuron cultures were devoid of mast cells confirmed by negative staining for c-kit or toluidine blue. In addition, in cultured enteric neurons the excitatory action of compound 48/80 was preserved in the presence of histamine H1 and H2 antagonists. The mast cell stabilizer cromolyn attenuated compound 48/80 and nicotine evoked Ca++ transients in mast cell-free enteric neuron cultures. Conclusions/Significance The results showed direct excitatory action of compound 48/80 on enteric neurons and visceral afferents. Therefore, functional changes measured in tissue or animal models may involve a mast cell independent effect of compound 48/80 and cromolyn

A Critical Temporal Window for Selectin-dependent CD4+ Lymphocyte Homing and Initiation of Late-Phase Inflammation in Contact Sensitivity

Contact sensitivity (CS) is an inflammatory disorder characterized by early and late phases of leukocyte recruitment. We used a noninvasive intravital microscopy technique allowing for the direct visualization of leukocyte rolling and adhesion on blood vessel endothelium. By blocking specific adhesion molecules, we elucidated the molecular mechanisms mediating early leukocyte recruitment to be E- and P-selectin and demonstrated that leukocyte recruitment in the late phase had a different adhesive profile (mainly α4-integrin). Complete blockade of E- and P-selectin within the first 2 h of leukocyte–endothelial cell interactions (but not later) eliminated selectin-independent leukocyte recruitment at 24 h. Despite the predominance of neutrophils in the early phase, specific elimination of CD4+ lymphocytes in the early phase eliminated the late response. CD4+ lymphocytes homed to skin via E- and P-selectin within the early phase and induced the late phase response. Addition of these same CD4+ lymphocytes 2 h after antigen challenge was too late for these cells to home to the skin and induce late phase responses. Our data clearly demonstrate that the antigen-challenged microenvironment is only accessible to CD4+ lymphocytes for the first 2 h, and that this process is essential for the subsequent recruitment of other leukocyte populations in late phase responses

Resolvin D2 is a potent regulator of leukocytes and controls microbial sepsis

National Institutes of Health grants GM-38765 and P50-DE016191 (C.N.S.), Welcome Trust Programme grant 086867/Z/08/Z (R.J.F. and M.P.) and Project grant 085903/Z/08 (R.J.F.) and Arthritis Research Campaign UK fellowships 18445 and 18103 (to L.V.N. and D.C., respectively). M.S. received a National Research Service Award from the NHLBI (HL087526)

Invariant natural killer T cells act as an extravascular cytotoxic barrier for joint-invading Lyme Borrelia

SignificanceInvariant natural killer T cells (iNKT) have been found primarily patrolling inside blood vessels in the liver, where they respond to bacterial glycolipids presented by CD1d on liver macrophages. We show joint iNKT cells are localized outside of blood vessels and respond directly to the joint-homing pathogen, Borrelia burgdorferi, which causes Lyme borreliosis using multichannel spinning-disk intravital microscopy. These iNKT cells interacted with B. burgdorferi at the vessel wall and disrupted its dissemination attempts into joints. Successful penetrance of B. burgdorferi out of the vasculature and into the joint tissue was met by a lethal attack by extravascular iNKT cells through a granzyme-dependent pathway. These results suggest a critical extravascular iNKT cell immune surveillance in joints that functions as a cytotoxic barrier

Intraluminal crawling of neutrophils to emigration sites: a molecularly distinct process from adhesion in the recruitment cascade

The prevailing view is that the β2-integrins Mac-1 (αMβ2, CD11b/CD18) and LFA-1 (αLβ2, CD11a/CD18) serve similar biological functions, namely adhesion, in the leukocyte recruitment cascade. Using real-time and time-lapse intravital video-microscopy and confocal microscopy within inflamed microvessels, we systematically evaluated the function of Mac-1 and LFA-1 in the recruitment paradigm. The chemokine macrophage inflammatory protein-2 induced equivalent amounts of adhesion in wild-type and Mac-1−/− mice but very little adhesion in LFA-1−/− mice. Time-lapse video-microscopy within the postcapillary venules revealed that immediately upon adhesion, there is significant intraluminal crawling of all neutrophils to distant emigration sites in wild-type mice. In dramatic contrast, very few Mac-1−/− neutrophils crawled with a 10-fold decrease in displacement and a 95% reduction in velocity. Therefore, Mac-1−/− neutrophils initiated transmigration closer to the initial site of adhesion, which in turn led to delayed transmigration due to movement through nonoptimal emigration sites. Interestingly, the few LFA-1−/− cells that did adhere crawled similarly to wild-type neutrophils. Intercellular adhesion molecule-1 but not intercellular adhesion molecule-2 mediated the Mac-1–dependent crawling. These in vivo results clearly delineate two fundamentally different molecular mechanisms for LFA-1 and Mac-1 in vivo, i.e., LFA-1–dependent adhesion followed by Mac-1–dependent crawling, and both steps ultimately contribute to efficient emigration out of the vasculature

Долгосрочные результаты клинического применения тотального эндопротеза коленного сустава «Universal»

The objective - to evaluate long-term results and survival rates of Universal condylar knee prosthesis. Material and methods. There were a total of 121 total knee joint replacements in the set with 107 patients aged 71.3 years on average (52-86 years). A total of 115 knees diagnosed with osteoarthritis of the 3-4th degree were indicated for the surgery, and there were 6 patients with the diagnosis of rheumatoid arthritis. Functional outcomes were evaluated using the Knee Society Score (KSS), Results. The assessment of the knee state on a scale KSS average clinical section KSS (knee score) was 48.2, and functional (function score) - 46,8 points. After surgery, the indices increased to 87.4 points and 85.8 points, respectively. One complication was described during the surgery, namely - the fracture of the medial tibia condyle (0.8%). In the early post-surgery period, peroneal nerve paresis was observed in two patients (1.6%). In the postoperative period, disorders of the wound healing were observed in 6 patients (4.9%), which were healed successfully in a conservative way. In the late post-surgery period, there were infectious complications in the knee joint in 4 knee joints (3.3%). Aseptic loosening was observed in 4 cases out of 117 endoprostheses (3.4%). It always concerned the loosening of tibial component. The loosening of the femoral component was not observed. In the period from the implantation until June 2014, which is 16-22 years after the implantation, there are 16 patients in total surviving, who had a total of 21 implanted endoprostheses. Among them there are no signs of a loosening only in 4 patients (19%); there was an apparent radiolucent line up until 2 mm with a sclerotic rim under the tibial component. All the patients were without clinical symptoms for the loosening. Six female patients (28.5%) state troubles in the area of the femoro-patellar joint, where there is a lateralization of the patella, apparent on the X-ray images. Two patients (1.6%) experienced a periprosthetic femur fracture during the period of observation. It was possible to resolve this state by the distal femoral nail osteosynthesis. Upon assessing the results via the Kaplan-Meier curve method, the survival index was 98.7% after 7 years, 94.3% - after 22 years and 91.8% - after 22 years. Conclusion. The result of this study had showed the reliability of Universal prosthesis which can be recommended for the treatment of patients with degenerative knee disea;Цель данной работы - оценка долгосрочных результатов применения тотального эндопротеза сустава Universal. Материал и методы. В изучаемую группу вошли 107 пациентов со средним возрастом 71,3 лет (52-86 лет), которым был имплантирован 121 тотальный эндопротез коленного сустава. В 115 наблюдениях показанием к операции был гонартроз 3-4 степени и в 6 наблюдениях - ревматоидный артрит. Перед операцией и спустя три месяца после ее выполнения была проведена клинико-функциональная оценка состояния пациентов по балльной системе Американского общества коленного сустава (KSS). Результаты. В ходе операций произошло одно (0,8%) осложнение, а именно - перелом медиального мыщелка большеберцовой кости. В раннем послеоперационном периоде у двух пациентов (1,6%) наблюдался паралич малоберцового нерва. В послеоперационном периоде у 6 (4,9%) больных наблюдалось замедление заживления раны, которое удалось купировать консервативными методами. В позднем послеоперационном периоде в четырех случаях (3,3%) возникли инфекционные осложнения. Асептическое расшатывание эндопротезов наблюдалось в 4 случаях (3,4%) из 117. Во всех случаях речь шла о расшатывании большеберцового компонента, нестабильности бедренного компонента не наблюдалось. С момента имплантации до июня 2014 г., то есть спустя 16-22 года после имплантации, дожили 16 пациентов, которым был имплантирован в общей сложности 21 эндопротез. Из них только у 4 (19%) пациентов не было обнаружено никаких рентгенологических признаков расшатывания, а у всех остальных под большеберцовым компонентом наблюдались рентгенопрозрачные линии шириной 2 мм со склеротическим ободком. Тем не менее, ни у одного из пациентов не было выявлено клинических признаков расшатывания. Шесть (28,5%) пациентов предъявляли жалобы на дискомфорт в области пателло-феморального сустава, при этом рентгенологическое обследование выявило лате- рализацию надколенника. У двух пациентов (1,6%) за период наблюдения произошли перипротезные переломы бедренной кости - в обоих случаях выполнен остеосинтез дистальным бедренным штифтом. При оценке результатов по кривой Каплана - Мейера индекс выживания через 7 лет составил 98,7%, через 11 лет - 94,3% и спустя 22 года - 91,8%. Заключение. Результаты исследования показали, что это надежный эндопротез, который имеет свою историю и может быть рекомендован для лечения дегенеративных повреждений коленного сустава как при остеоартрозе, так и у пациентов с ревматоидным артритом

Molecular Mechanisms Involved in Vascular Interactions of the Lyme Disease Pathogen in a Living Host

Hematogenous dissemination is important for infection by many bacterial pathogens, but is poorly understood because of the inability to directly observe this process in living hosts at the single cell level. All disseminating pathogens must tether to the host endothelium despite significant shear forces caused by blood flow. However, the molecules that mediate tethering interactions have not been identified for any bacterial pathogen except E. coli, which tethers to host cells via a specialized pillus structure that is not found in many pathogens. Furthermore, the mechanisms underlying tethering have never been examined in living hosts. We recently engineered a fluorescent strain of Borrelia burgdorferi, the Lyme disease pathogen, and visualized its dissemination from the microvasculature of living mice using intravital microscopy. We found that dissemination was a multistage process that included tethering, dragging, stationary adhesion and extravasation. In the study described here, we used quantitative real-time intravital microscopy to investigate the mechanistic features of the vascular interaction stage of B. burgdorferi dissemination. We found that tethering and dragging interactions were mechanistically distinct from stationary adhesion, and constituted the rate-limiting initiation step of microvascular interactions. Surprisingly, initiation was mediated by host Fn and GAGs, and the Fn- and GAG-interacting B. burgdorferi protein BBK32. Initiation was also strongly inhibited by the low molecular weight clinical heparin dalteparin. These findings indicate that the initiation of spirochete microvascular interactions is dependent on host ligands known to interact in vitro with numerous other bacterial pathogens. This conclusion raises the intriguing possibility that fibronectin and GAG interactions might be a general feature of hematogenous dissemination by other pathogens

Cognitive foundations of impartial punitive decision making in organizations: attribution and abstraction

Partial decision making about disciplinary responses to misbehavior is generally considered unfair and undermines the effectiveness of punishment. Nonetheless, organizational actors often struggle to remain impartial in situations that call for punishment. Impartiality appears specifically hard to obtain when some element of the transgression reflects badly upon the punisher themselves, for instance, when in the past the punisher has benefited from the misbehavior, even if just derivatively. In this paper, we argue that in such cases, punishers tend to defensively attribute causes of the transgression to the circumstances in order to protect their own self‐image, thus leading them to relatively lenient punishments. However, we also suggest that psychological impartiality can be obtained through cognitive abstraction. An abstract understanding (high‐level construal) of the punitive situation puts the focus squarely on the gist of the situation and makes circumstantial details less likely to be cognitively available. This hinders defensive circumstantial attribution. We show in a field study and an experiment that partiality in making decisions about punishments occurs under conditions of low‐level (i.e., concrete) construal, whereas impartiality is facilitated by high‐level (i.e., abstract) construal