The role of the amphibian kidney and bladder in the regulation of acid–base relevant ions

1989 ◽  
Vol 67 (12) ◽  
pp. 3064-3069 ◽  
Author(s):  
Daniel P. Toews ◽  
Daniel F. Stiffler
Keyword(s):  
Animal Studies ◽  
Intact Animal ◽  
Bladder Function ◽  
Whole Body ◽  
Transport Mechanisms ◽  
Acid Base ◽  
Cellular Mechanisms ◽  
Physiological Conditions

The amphibian bladder and kidneys have proven to be excellent structures for in vitro investigations of ion-transport mechanisms and cellular mechanisms of hormone action. Very often, however, the normal physiological conditions that exist in the intact animal have not been duplicated in the particular experimental setup. On the other hand, whole-animal studies relating to kidney and bladder function are somewhat rare because it is technically very difficult to separate the relative contributions of the kidney, bladder, and skin to processes such as whole-body acid–base regulation. In this review we attempt to describe the most significant advances of in vitro studies as they relate to acid–base regulation and to integrate these experiments with the limited number of investigations performed on whole-animal preparations.

scholarly journals Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities

2021 ◽  
Vol 22 (11) ◽  
pp. 5705
Author(s):  
Karolina Szewczyk-Golec ◽  
Marta Pawłowska ◽  
Roland Wesołowski ◽  
Marcin Wróblewski ◽  
Celestyna Mila-Kierzenkowska
Keyword(s):  
Oxidative Stress ◽  
Animal Studies ◽  
Treatment Options ◽  
Natural Antioxidants ◽  
Redox Status ◽  
Host Cells ◽  
Common Disease ◽  
Parasite Viability

Toxoplasma gondii is an apicomplexan parasite causing toxoplasmosis, a common disease, which is most typically asymptomatic. However, toxoplasmosis can be severe and even fatal in immunocompromised patients and fetuses. Available treatment options are limited, so there is a strong impetus to develop novel therapeutics. This review focuses on the role of oxidative stress in the pathophysiology and treatment of T. gondii infection. Chemical compounds that modify redox status can reduce the parasite viability and thus be potential anti-Toxoplasma drugs. On the other hand, oxidative stress caused by the activation of the inflammatory response may have some deleterious consequences in host cells. In this respect, the potential use of natural antioxidants is worth considering, including melatonin and some vitamins, as possible novel anti-Toxoplasma therapeutics. Results of in vitro and animal studies are promising. However, supplementation with some antioxidants was found to promote the increase in parasitemia, and the disease was then characterized by a milder course. Undoubtedly, research in this area may have a significant impact on the future prospects of toxoplasmosis therapy.

scholarly journals Subinhibitory Antimicrobial Concentrations: A Review of In Vitro and In Vivo Data

1992 ◽  
Vol 3 (4) ◽  
pp. 193-201 ◽  
Author(s):  
George G Zhanel ◽  
Daryl J Hoban ◽  
Godfrey KM Harding
Keyword(s):  
Antimicrobial Activity ◽  
Animal Studies ◽  
Molecular Level ◽  
Bacterial Virulence ◽  
Antibacterial Effects ◽  
Wide Range ◽  
Immune Defences

Antimicrobial activity is not an ‘all or none’ effect. An increase in the rate and extent of antimicrobial action is usually observed over a wide range of antimicrobial concentrations. Subinhibitory antimicrobial concentrations are well known to produce significant antibacterial effects, and various antimicrobials at subinhibitory concentrations have been reported to inhibit the rate of bacterial growth. Bacterial virulence may be increased or decreased by subinhibitory antimicrobial concentrations by changes in the ability of bacteria to adhere to epithelial cells or by alterations in bacterial susceptibility to host immune defences. Animal studies performed in rats, hamsters and rabbits demonstrate decreased bacterial adherence, reduced infectivity and increased survival of animals treated with subinhibitory antimicrobial concentrations compared to untreated controls. The major future role of investigation of subinhibitory antimicrobial concentrations will be to define more fully, at a molecular level, how antimicrobials exert their antibacterial effects.

scholarly journals Cellular adaptations in fat tissue of exercise-trained miniature swine: role of excess energy intake

2000 ◽  
Vol 88 (3) ◽  
pp. 881-887 ◽  
Author(s):  
Gale B. Carey
Keyword(s):  
Adipose Tissue ◽  
Energy Intake ◽  
Excess Energy ◽  
Fat Tissue ◽  
Cellular Mechanisms ◽  
Miniature Swine ◽  
Extracellular Adenosine

This study examined the influence of energy expenditure and energy intake on cellular mechanisms regulating adipose tissue metabolism. 1 Twenty-four swine were assigned to restricted-fed sedentary, restricted-fed exercise-trained, full-fed sedentary, or full-fed exercise-trained groups. After 3 mo of treatment, adipocytes were isolated and adipocyte size, adenosine A1 receptor characteristics, and lipolytic sensitivity were measured. Swine were infused with epinephrine during which adipose tissue extracellular adenosine, plasma fatty acids, and plasma glycerol were measured. Results revealed that adipocytes isolated from restricted-fed exercised swine had a smaller diameter, a lower number of A1 receptors, and a greater sensitivity to lipolytic stimulation, compared with adipocytes from full-fed exercised swine. Extracellular adenosine levels were transiently increased on infusion of epinephrine in adipose tissue of restricted-fed exercised but not full-fed exercised swine. These results suggest a role for adenosine in explaining the discrepancy between in vitro and in vivo lipolysis findings and underscore the notion that excess energy intake dampens the lipolytic sensitivity of adipocytes to β-agonists and adenosine, even if accompanied by exercise training.

Plasminogen: an enigmatic zymogen

Blood ◽  
2021 ◽  
Author(s):  
Charithani B Keragala ◽  
Robert L Medcalf
Keyword(s):  
Animal Studies ◽  
Wound Repair ◽  
Active Form ◽  
Cell Behaviour ◽  
Surface Receptors ◽  
Enzymatic Cascades ◽  
Inflammatory Processes ◽  
Over 40 Years

Plasminogen is an abundant plasma protein that exists in various zymogenic forms. Plasmin, the proteolytically active form of plasminogen, is known for its essential role in fibrinolysis. The therapeutic targeting of the fibrinolytic system to date has been for two purposes: to promote plasmin generation for thromboembolic conditions, or to stop plasmin to reduce bleeding. However, both plasmin and plasminogen serve other important functions, some of which are unrelated to fibrin removal. Indeed, for over 40 years, the anti-fibrinolytic agent, tranexamic acid, has been administered for its serendipitously discovered skin whitening properties. Plasmin also plays an important role in the removal of misfolded/aggregated proteins and can trigger other enzymatic cascades including complement. In addition, plasminogen, via binding to one of its dozen cell-surface receptors, can modulate cell behaviour and further influence immune and inflammatory processes. Plasminogen administration itself has been reported to improve thrombolysis and to accelerate wound repair. While many of these more recent findings have been derived from in vitro or animal studies, the use of anti-fibrinolytics to reduce bleeding in humans has revealed additional clinically relevant consequences, particularly in relation to reducing infection risk that is independent of its haemostatic effects. The finding that many viruses harness the host plasminogen to aid infectivity has suggested that anti-fibrinolytic agents may have anti-viral benefits. Here we review the broadening role of the plasminogen activating system in physiology and pathophysiology and how manipulation of this system may be harnessed for benefits unrelated to its conventional application in thrombosis and haemostasis.

scholarly journals Ozone Therapy as Adjuvant for Cancer Treatment: Is Further Research Warranted?

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Bernardino Clavo ◽  
Norberto Santana-Rodríguez ◽  
Pedro Llontop ◽  
Dominga Gutiérrez ◽  
Gerardo Suárez ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Immune Modulation ◽  
Animal Studies ◽  
Potential Role ◽  
Randomized Clinical Trials ◽  
Tumor Hypoxia ◽  
Tumor Resection ◽  
Ozone Therapy

Introduction. This article provides an overview of the potential use of ozone as an adjuvant during cancer treatment.Methods. We summarize the findings of the most relevant publications focused on this goal, and we include our related clinical experience.Results. Over several decades, prestigious journals have publishedin vitrostudies on the capacity of ozone to induce direct damage on tumor cells and, as well, to enhance the effects of radiotherapy and chemotherapy. Indirect effects have been demonstrated in animal models: immune modulation by ozone alone and sensitizing effect of radiotherapy by concurrent ozone administration. The effects of ozone in modifying hemoglobin dissociation curve, 2,3-diphosphoglycerate levels, locoregional blood flow, and tumor hypoxia provide additional support for potential beneficial effects during cancer treatment. Unfortunately, only a few clinical studies are available. Finally, we describe some works and our experience supporting the potential role of local ozone therapy in treating delayed healing after tumor resection, to avoid delays in commencing radiotherapy and chemotherapy.Conclusions.In vitroand animal studies, as well as isolated clinical reports, suggest the potential role of ozone as an adjuvant during radiotherapy and/or chemotherapy. However, further research, such as randomized clinical trials, is required to demonstrate its potential usefulness as an adjuvant therapeutic tool.

scholarly journals Mast Cells in Cardiovascular Disease: From Bench to Bedside

2019 ◽  
Vol 20 (14) ◽  
pp. 3395 ◽  
Author(s):  
Hermans ◽  
Lennep ◽  
van Daele ◽  
Bot
Keyword(s):  
Cardiovascular Disease ◽  
Mast Cells ◽  
Animal Studies ◽  
Intraplaque Hemorrhage ◽  
Hematological Disease ◽  
Plaque Instability ◽  
Clonal Proliferation ◽  
Progression Of Atherosclerosis

Mast cells are pluripotent leukocytes that reside in the mucosa and connective tissue. Recent studies show an increased prevalence of cardiovascular disease among patients with mastocytosis, which is a hematological disease that is characterized by the accumulation of mast cells due to clonal proliferation. This association suggests an important role for mast cells in cardiovascular disease. Indeed, the evidence establishing the contribution of mast cells to the development and progression of atherosclerosis is continually increasing. Mast cells may contribute to plaque formation by stimulating the formation of foam cells and causing a pro-inflammatory micro-environment. In addition, these cells are able to promote plaque instability by neo-vessel formation and also by inducing intraplaque hemorrhage. Furthermore, mast cells appear to stimulate the formation of fibrosis after a cardiac infarction. In this review, the available data on the role of mast cells in cardiovascular disease are summarized, containing both in vitro research and animal studies, followed by a discussion of human data on the association between cardiovascular morbidity and diseases in which mast cells are important: Kounis syndrome, mastocytosis and allergy.

Physiological effects of endogenous ouabain: control of intracellular Ca2+ stores and cell responsiveness

1993 ◽  
Vol 264 (6) ◽  
pp. C1367-C1387 ◽  
Author(s):  
M. P. Blaustein
Keyword(s):  
Steady State ◽  
Cell Types ◽  
Whole Body ◽  
Cellular Mechanisms ◽  
Signaling Mechanism ◽  
Physiological Processes ◽  
Endogenous Ouabain ◽  
Adrenal Cortical Hormone ◽  
Salt And Water Balance

Ouabain is a well-known compound but a newly discovered adrenal cortical hormone that plays a role in cell Na+ regulation and in whole body salt and water balance. Ouabain may also be a paracrine hormone and may be secreted by some central nervous system neurons as well as by other types of cells. This article focuses on the cellular mechanisms that underlie the physiological (and pathophysiological) effects of ouabain. Ouabain directly inhibits the plasmalemmal Na+ pump in a variety of cell types. Low ouabain concentrations cause, in the steady state, a modest rise in the cytosolic Na+ concentration but only a minimal decline in membrane potential. All Na+ gradient-dependent processes may thereby be affected, albeit to only a small extent. Most important, however, is the secondary redistribution of Ca2+, mediated by Na(+)-Ca2+ exchange, that should slightly increase the cytosolic free Ca2+ concentration ([Ca2+]cyt). As a result of Ca2+ sequestration in intracellular stores [the endoplasmic and/or sarcoplasmic reticulum (ER/SR)], however, a new steady state is achieved with a slightly increased [Ca2+]cyt but a substantially augmented Ca2+ store; thus the ER/SR effectively acts as a Ca2+ amplifier. This extra stored Ca2+ is then available for mobilization whenever the cells are activated. Cytosolic Ca2+ is a key signaling mechanism in virtually all cells: it controls numerous physiological processes such as contraction, secretion, and excitability. Thus ouabain may modulate cell responsiveness via its influence on ER/SR Ca2+ stores. With these principles in mind, we examine evidence that endogenous ouabain may play a role in numerous physiological and pathophysiological processes associated with altered fluid and electrolyte metabolism and deviations from the normal blood pressure-blood volume relationship. We discuss the possible participation of ouabain in the regulation of vascular tone and then consider the putative role of ouabain in several forms of hypertension, congestive heart failure, thyroid and adrenocortical dysfunction, and diabetes mellitus, as well as in the adaptation to high altitude.

ROLE OF NA+, K+-ATPase IN MUSCULAR ENERGY EXPENDITURE OF WARM- AND COLD-EXPOSED SHEEP

1982 ◽  
Vol 62 (1) ◽  
pp. 123-132 ◽  
Author(s):  
V. A. GREGG ◽  
L. P. MILLIGAN
Keyword(s):  
Skeletal Muscle ◽  
Energy Expenditure ◽  
Cold Exposure ◽  
Whole Body ◽  
Random Group ◽  
Key Words Skeletal Muscle ◽  
Maximum Inhibition ◽  
Functional Membrane

The role of Na+, K+-ATPase in the energy expenditure of sheep skeletal muscle and the influence of exposure to cold on this role were studied. An in vitro preparation of muscle was developed that achieved O2 availability and a functional membrane potential. A 10−6 M concentration of ouabain yielded a maximum inhibition of respiration of 38.9 ± 1.8% using muscle preparations from a random group of sheep. Whole body and muscle O2 consumptions and ouabain-sensitive muscle respiration were measured for warm- and cold-exposed sheep fed at maintenance or 1150 g of alfalfa pellets per day. Cold exposure increased whole body and muscle O2 consumption. Inhibition of respiration by ouabain was 37.6 ± 1.2% and 41.0 ± 3.6% for warm- and cold-exposed sheep fed at maintenance, and 28.5 ± 4.0% and 45.0 ± 4.0% for warm- and cold-exposed sheep fed 1150 g of alfalfa pellets per day. The increase in the ouabain-sensitive component of respiration accounted for 48–79% of the increased O2 consumption of muscle from cold-exposed sheep. It was concluded that the Na+, K+-ATPase of sheep muscle is a major means of energy expenditure and has an important role in the increased thermogenesis resulting from cold exposure. Key words: Skeletal muscle, Energy expenditure, muscle respiration, cold thermogenesis, sodium-potassium transport

scholarly journals Protective Effects of Dietary Antioxidants against Vanadium-Induced Toxicity: A Review

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Iwona Zwolak
Keyword(s):  
Oxidative Stress ◽  
Animal Studies ◽  
Toxic Metal ◽  
Protective Effects ◽  
Dietary Antioxidants ◽  
Vanadium Toxicity ◽  
Preventive Effects

Vanadium (V) in its inorganic forms is a toxic metal and a potent environmental and occupational pollutant and has been reported to induce toxic effects in animals and people. In vivo and in vitro data show that high levels of reactive oxygen species are often implicated in vanadium deleterious effects. Since many dietary (exogenous) antioxidants are known to upregulate the intrinsic antioxidant system and ameliorate oxidative stress-related disorders, this review evaluates their effectiveness in the treatment of vanadium-induced toxicity. Collected data, mostly from animal studies, suggest that dietary antioxidants including ascorbic acid, vitamin E, polyphenols, phytosterols, and extracts from medicinal plants can bring a beneficial effect in vanadium toxicity. These findings show potential preventive effects of dietary antioxidants on vanadium-induced oxidative stress, DNA damage, neurotoxicity, testicular toxicity, and kidney damage. The relevant mechanistic insights of these events are discussed. In summary, the results of studies on the role of dietary antioxidants in vanadium toxicology appear encouraging enough to merit further investigations.

scholarly journals A Review of the Role of Neurotensin and Its Receptors in Colorectal Cancer

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Shengyang Qiu ◽  
Gianluca Pellino ◽  
Francesca Fiorentino ◽  
Shahnawaz Rasheed ◽  
Ara Darzi ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Animal Studies ◽  
In Vivo Studies ◽  
Signalling Pathways ◽  
Diagnostic Biomarker ◽  
Gi Tract ◽  
Cellular Receptors

Neurotensin (NTS) is a physiologically occurring hormone which affects the function of the gastrointestinal (GI) tract. In recent years, NTS, acting through its cellular receptors (NTSR), has been implicated in the carcinogenesis of several cancers. In colorectal cancer (CRC), a significant body of evidence, from in vitro and in vivo studies, is available which elucidates the molecular biology of NTS/NTSR signalling and the resultant growth of CRC cells. There is growing clinical data from human studies which corroborate the role NTS/NTSR plays in the development of human CRC. Furthermore, blockade and modulation of the NTS/NTSR signalling pathways appears to reduce CRC growth in cell cultures and animal studies. Lastly, NTS/NTSR also shows potential of being utilised as a diagnostic biomarker for cancers as well as targets for functional imaging. We summarise the existing evidence and understanding of the role of NTS and its receptors in CRC.

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