scholarly journals Vascular biology of hydrogen sulfide

2017 ◽  
Vol 312 (5) ◽  
pp. C537-C549 ◽  
Author(s):  
Nancy L. Kanagy ◽  
Csaba Szabo ◽  
Andreas Papapetropoulos

Hydrogen sulfide (H2S) is a ubiquitous signaling molecule with important functions in many mammalian organs and systems. Observations in the 1990s ascribed physiological actions to H2S in the nervous system, proposing that this gasotransmitter acts as a neuromodulator. Soon after that, the vasodilating properties of H2S were demonstrated. In the past decade, H2S was shown to exert a multitude of physiological effects in the vessel wall. H2S is produced by vascular cells and exhibits antioxidant, antiapoptotic, anti-inflammatory, and vasoactive properties. In this concise review, we have focused on the impact of H2S on vascular structure and function with an emphasis on angiogenesis, vascular tone, vascular permeability and atherosclerosis. H2S reduces arterial blood pressure, limits atheromatous plaque formation, and promotes vascularization of ischemic tissues. Although the beneficial properties of H2S are well established, mechanistic insights into the molecular pathways implicated in disease prevention and treatment remain largely unexplored. Unraveling the targets and downstream effectors of H2S in the vessel wall in the context of disease will aid in translation of preclinical observations. In addition, acute regulation of H2S production is still poorly understood and additional work delineating the pathways regulating the enzymes that produce H2S will allow pharmacological manipulation of this pathway. As the field continues to grow, we expect that H2S-related compounds will find their way into clinical trials for diseases affecting the blood vessels.

Author(s):  
Heather Thon ◽  
Amy Krist

Understanding invasive species impacts is critical to determining how an ecosystem may function after an introduction. Invasive species can alter the structure and function of ecosystems, reduce biological diversity, and alter communities through predation, facilitation and competition. In the past 30 years, the invasive New Zealand mud snail (Potamopyrgus antipodarum) has established in areas of conservation concern in the American West including Yellowstone National Park. To develop a greater understanding of the impact of P. antipodarum on the native co-occurring snail, Fossaria (Bakerilymnaea) bulimoides group, we conducted two experiments to assess the interactions occurring between these snails. We found that F. bulimoides growth was reduced by all interactors, but especially by P. antipodarum. In addition, growth of F. bulimoides was much more affected by high biomass of snails than P. antipodarum. P. antipodarum grew more in the presence of interactors and their growth was facilitated by the presence of the native snail F. bulimoides.


2015 ◽  
Vol 10 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Nyankomo Marwa ◽  
Stephen Zhanje

Abstract The finance growth-nexus debates have been contentious over the past three decades both empirically and theoretically. To contribute to this debate, the current paper presents a concise review of finance-growths nexus theoretical development and the current debate around growth-finance nexus theories. Then, it extends the current theoretical debate to include development finance within the broader scheme of finance-growth discourse. The key emerging trend is that, most of the contemporary theories trying to explain finance growth nexus have been exclusively focusing on the standard finance in general. Little attention has been devoted to understand the role of development finance on finance-growth nexus. It concludes that, for a more comprehensive understanding of the finance growth nexus, the role of development finance should be integrated in theory of finance-growth nexus. The paper demonstrates that conventional model of finance-growth nexus is more likely to underestimate the magnitude of the impact of finance on economic growth especially for less developed countries. The paper suggests that, a model which breakdown the finance into standard finance subgroup and development finance subgroup may provide more accurate and insightful findings.


2020 ◽  
Vol 17 (8) ◽  
pp. 946-957
Author(s):  
Ravindra V. Kupwade

The chemistry of hypervalent iodine compounds has been experiencing considerable attention of organic chemists during the past few years. Hypervalent iodine reagents have found ubiquitous applications in organic synthesis because of their mild and highly chemoselective oxidizing properties, easy commercial availability, and environmental benign character. Along with oxidation of alcohol, they have also shown to be useful in number of organic transformations which include oxidative functionalization of carbonyl compounds, catalytic imidations, cyclization, oxidative coupling of phenols, amines and related compounds. Among various hypervalent iodine reagents, iodine-V compounds (λ5-iodanes) have attracted much attention in recent years. This review narrates the particular advances in iodine (V) reagents with special emphasis on the use of DMP in organic transformations.


2022 ◽  
Author(s):  
Nienke Willemsen ◽  
Isabel Arigoni ◽  
Maja Studencka-Turski ◽  
Elke Krüger ◽  
Alexander Bartelt

Objective: Regulation of proteasomal activity is an essential component of cellular proteostasis and function. This is evident in patients with mutations in proteasome subunits and regulators, who suffer from proteasome-associated autoinflammatory syndromes (PRAAS). These patients display lipodystrophy and fevers, which may be partly related to adipocyte malfunction and abnormal thermogenesis in adipose tissue. However, the cell-intrinsic pathways that could underlie these symptoms are unclear. Here, we investigate the impact of two proteasome subunits implicated in PRAAS, Psmb4 and Psmb8, on differentiation, function and proteostasis of brown adipocytes. Methods: In immortalized mouse brown pre-adipocytes, levels of Psmb4, Psmb8, and downstream effectors genes were downregulated through reverse transfection with siRNA. Adipocytes were differentiated and analyzed with various assays of adipogenesis, lipogenesis, lipolysis, inflammation, and respiration. Results: Loss of Psmb4, but not Psmb8, disrupted proteostasis and adipogenesis. Proteasome function was reduced upon Psmb4 loss, but partly recovered by the activation of Nuclear factor, erythroid-2, like-1 (Nfe2l1). In addition, cells displayed higher levels of surrogate inflammation and stress markers, including Activating transcription factor-3 (Atf3). Simultaneous silencing of Psmb4 and Atf3 lowered inflammation and restored adipogenesis. Conclusions: Our study shows that Psmb4 is required for adipocyte development and function in cultured adipocytes. These results imply that in humans with PSMB4 mutations, PRAAS-associated lipodystrophy is partly caused by disturbed adipogenesis. While we uncover a role for Nfe2l1 in the maintenance of proteostasis under these conditions, Atf3 is a key effector of inflammation and blocking adipogenesis. In conclusion, our work highlights how proteasome dysfunction is sensed and mitigated by the integrated stress response in adipocytes with potential relevance for PRAAS patients and beyond.


1995 ◽  
Vol 13 (3) ◽  
pp. 273-296 ◽  
Author(s):  
O Yiftachel ◽  
I Alexander

In this paper the dynamic relations between the state, society, and metropolitan planning are explored. The changing role and function of the state in the context of rapid restructuring of economic and social relations in Australia during the past decade are discussed, along with the impact of processes such as globalisation, cyclic recessions, and the growing assertion of local communities on the state. The influence of these processes on metropolitan planning, as an arm of the state which mediates between development interests and local communities, is then assessed from a theoretical perspective. Given the identified processes and changes, it is argued that metropolitan planning has become increasingly constrained in its ability to influence the nature and location of urban development in 1990s Australia. The validity of this argument is examined against the case of metropolitan planning in Perth during the past decade. Three key aspects of the changing nature of planning in Perth are studied in detail: A 1987 proposal for a new metropolitan strategy; a 1990 adopted metropolitan plan which derived from the 1987 proposal; and several redevelopment initiatives currently under consideration. It is concluded that the Western Australian state—and subsequently metropolitan planning—have experienced significant challenges to their ability to influence urban change. The constraints imposed on metropolitan planning are simultaneously due to economic pressures ‘from above’ and community pressures ‘from below’. Finally, it is observed that this process possesses a regresive potential, and that metropolitan planning should restructure in order to respond effectively and equitably to recent economic and social changes.


Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.


Author(s):  
Leslie M. Loew

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.


2016 ◽  
Vol 1 (13) ◽  
pp. 162-168
Author(s):  
Pippa Hales ◽  
Corinne Mossey-Gaston

Lung cancer is one of the most commonly diagnosed cancers across Northern America and Europe. Treatment options offered are dependent on the type of cancer, the location of the tumor, the staging, and the overall health of the person. When surgery for lung cancer is offered, difficulty swallowing is a potential complication that can have several influencing factors. Surgical interaction with the recurrent laryngeal nerve (RLN) can lead to unilateral vocal cord palsy, altering swallow function and safety. Understanding whether the RLN has been preserved, damaged, or sacrificed is integral to understanding the effect on the swallow and the subsequent treatment options available. There is also the risk of post-surgical reduction of physiological reserve, which can reduce the strength and function of the swallow in addition to any surgery specific complications. As lung cancer has a limited prognosis, the clinician must also factor in the palliative phase, as this can further increase the burden of an already compromised swallow. By understanding the surgery and the implications this may have for the swallow, there is the potential to reduce the impact of post-surgical complications and so improve quality of life (QOL) for people with lung cancer.


2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.


GeroPsych ◽  
2011 ◽  
Vol 24 (3) ◽  
pp. 143-154 ◽  
Author(s):  
Elmar Gräßel ◽  
Raffaela Adabbo

The burden of caregivers has been intensively researched for the past 30 years and has resulted in a multitude of individual findings. This review illustrates the significance of the hypothetical construct of perceived burden for the further development and design of the homecare situation. Following explanations regarding the term informal caregiver, we derive the construct burden from its conceptual association with the transactional stress model of Lazarus and Folkman. Once the extent and characteristics of burden have been set forth, we then present the impact of perceived burden as the care situation. The question of predictors of burden will lead into the last section from which implications can be derived for homecare and relief of caregivers.


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