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Vital Organs (vital + organ)
Selected AbstractsInflammation: A new candidate in modulating adult neurogenesisJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2008Sulagna Das Abstract Any pathological perturbation to the brain provokes a cascade of molecular and cellular events, which manifests in the form of microglial activation and release of various proinflammatory molecules. This eventually culminates in a profound neuroinflammatory reaction that characterizes the brain's response to stress, injury, or infection. The inflammatory cascade is an attempt by the system to eliminate the challenge imposed on the brain, clear the system of the dead and damaged neurons, and rescue the normal functioning of this vital organ. However, during the process of microglial activation, the proinflammatory mediators released exert certain detrimental effects, and neural stem cells and progenitor cells are likely to be affected. Here we review how the proliferation, maturation, and migration of the neural stem cells are modulated under such an inflammatory condition. The fate of the noncommitted neural stem cells and its differentiation potency are often under strict regulation, and these proinflammatory mediators seem to disrupt this critical balance and finely tune the neurogenesis pattern in the two niches of neurogenesis, the subventricular zone and the subgranular zone of the hippocampus. Moreover, the migration ability of these stem cells, which is important for localization to the proper site, is also affected in a major way by the chemokines released following inflammation. © 2007 Wiley-Liss, Inc. [source] Na+/H+ exchangers and the regulation of volumeACTA PHYSIOLOGICA, Issue 1-2 2006R. T. Alexander Abstract The regulation of volume is fundamental to life. There exist numerous conditions that can produce perturbations of cell volume. The cell has developed mechanisms to directly counteract these perturbations so as to maintain its physiological volume. Directed influx of the major extracellular cation, sodium, serves to counteract a decreased cell volume through the subsequent osmotically coupled movement of water to the intracellular space. This process, termed regulatory volume increase is often mediated by the ubiquitous sodium/hydrogen ion exchanger, NHE1. Similarly, the maintenance of intravascular volume is essential for the maintenance of blood pressure and consequently the proper perfusion of vital organs. Numerous mechanisms exist to counterbalance alterations in intravascular volume, not the least of which is the renal absorption of sodium filtered at the glomerulus. Two-thirds of filtered sodium and water are absorbed in the renal proximal tubule, a mechanism that intimately involves the apical sodium/hydrogen ion exchanger, NHE3. This isoform is fundamental to the maintenance and regulation of intravascular volume and blood pressure. In this article, the effects of cell volume on the activity of these different isoforms, NHE1 and NHE3, will be described and the consequences of their activity on intracellular and intravascular volume will be explored. [source] Comparative evaluation of heating ability and biocompatibility of different ferrite-based magnetic fluids for hyperthermia applicationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2007Pallab Pradhan Abstract In this study, lauric acid-coated, superparamagnetic, nanoparticle-based magnetic fluids of different ferrites (Fe3O4, MnFe2O4, and CoFe2O4) were prepared and compared in terms of heating ability and biocompatibility to evaluate the feasibility of use in hyperthermia treatment of cancer. All the magnetic fluids prepared had particles of average sizes 9,11 nm. Heating ability of these magnetic fluids was evaluated by calorimetric measurement of specific absorption rate (SAR) at 300 kHz frequency and 15 kA/m field. Fe3O4 and MnFe2O4 showed higher SAR (120 and 97 W/g of ferrite, respectively) than CoFe2O4 (37 W/g of ferrite). In vitro study on BHK 21 cell lines showed dose-dependent cell viability for all the magnetic fluids. Threshold-biocompatible ferrite concentration for all the magnetic fluids was 0.1 mg/mL. Above 0.2 mg/mL, CoFe2O4 was more toxic than the other magnetic fluids. On intravenous injection of different doses (50, 200, and 400 mg/kg body weight) of magnetic fluids in mice, no significant changes in hematological and biochemical parameters were observed for Fe3O4 and MnFe2O4. With CoFe2O4, an increase in SGPT levels at a dose rate of 400 mg/kg body weight was observed, indicating its mild hepatotoxic effect. However, histology of different vital organs showed no pathological changes for all the three magnetic fluids. Further, long term in vivo evaluation of biocompatibility of the lauric acid-coated ferrites is warranted. This study shows that lauric acid-coated, superparamagnetic Fe3O4 and MnFe2O4 may be used for hyperthermia treatment and are to be preferred over CoFe2O4. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Cytomorphological alterations of the thymus, spleen, head-kidney, and liver in cardinal fish (Apogonidae, Teleostei) as bioindicators of stressJOURNAL OF MORPHOLOGY, Issue 1 2006Lev Fishelson Abstract Morphological and cytological alterations at the light microscope (LM) and transmission electron microscope (TEM) levels were observed in the thymus, spleen, head-kidney, and liver of cardinal fishes (Apogonidae, Teleostei) from the Gulf of Aqaba, Red Sea, sampled from a strongly polluted site at the northern end of the gulf, and compared to similar samples from a clean, reference site. At the polluted site, the most prominent change was the formation of numerous deposits of cells rich in phagosomes with lipofucin, melanin granules, and phagocytosed debris, including a high increase in number and dimensions of Hassall's corpuscles and melano-macrophage centers. The number of Hassall's corpuscles was 20 (±8.0)/mm2 and of melano-macrophage centers 18 (±4.0)/mm2 at the polluted site, and 7.0 (±4.0)/m2 vs. 5.0 (±2.0)/mm2 respectively at the reference site. In numerous instances the head kidney's melano-macrophage centers in fishes from the polluted site were encapsulated by reticulocytes, a phenomenon recognized as a marker of neoplasmosis and possible malignancy. In the spleens of fishes from the polluted site, numerous deposits of cell debris, peroxisomes, and enlarged lysosomes were also observed. The livers (hepatopancreas) of fishes from polluted waters demonstrated very strong hyperlipogeny. Many of their hepatocytes were laden with lipid vesicles, fragmented endoplasmic reticulula, and aberrant mitochondria. Although the observed alterations in the glands and liver do not indicate any immediate threat to the life of the fish, they can become crucial with respect to energy turnover and fecundity trajectories. This study strongly suggests the use of cytological alterations in vital organs, such as were observed, as pathological biomarkers to environmental stress. J. Morphol. © 2005 Wiley-Liss, Inc. [source] Trauma: physiology, pathophysiology, and clinical implicationsJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 4 2006DACVA, DACVECC, William Muir DVM Abstract Objective: To review the physiology, pathophysiology, and consequences of trauma. The therapeutic implications of hypovolemia, hypotension, hypothermia, tissue blood flow, oxygen delivery, and pain will be discussed. Data Sources: Human and veterinary clinical and research studies. Human and veterinary data synthesis: Trauma is defined as tissue injury that occurs more or less suddenly as a result of violence or accident and is responsible for initiating hyothalamic,pituitary,adrenal axis, immunologic and metabolic responses that are designed to restore homeostasis. Tissue injury, hemorrhage, pain, and fear are key components of any traumatic event. Trauma and blood loss result in centrally integrated autonomic-mediated cardiovascular responses that are designed to increase heart rate, systemic vascular resistance, and maintain arterial blood pressure (ABP) to vital organs at the expense of blood flow to the gut and skeletal muscle. Severe trauma elicits exuberant physiologic, immunologic, and metabolic changes predisposing the animal to organ malfunction, a systemic inflammatory response, infection, and multiple organ dysfunctions. The combination of both central and local influences produces regional redistribution of blood flow among and within tissue beds which, when combined with impaired vascular reactivity, leads to maldistribution of blood flow to tissues predisposing to tissue hypoperfusion and impaired oxygen delivery and extraction. Gut blood flow and viability may serve as a sentinel of patient survival. These consequences are magnified in animals suffering from pain or that become hypothermic. Successful treatment of traumatized animals goes beyond the restoration of blood pressure and urine output, is dependent on a fundamental understanding of the pathophysiologic processes responsible for the animals current physical status, and incorporates the reduction of pain, stress, and the systemic inflammatory response and methods that restore microcirculatory blood flow and tissue oxygenation. Conclusions: Severe trauma is a multifaceted event and is exacerbated by hypothermia, pain, and stress. Therapeutic approaches must go beyond the simple restoration of vascular volume and ABP by maintaining tissue blood flow, restoring tissue oxygenation, and preventing systemic inflammation. [source] Pressor Therapy in Critically III PatientsJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2000ACVECC, ACVIM, James S. Wohl DVM Diplomate Summary Vasopressors are agents that increase systemic vascular resistance by increasing vasoconstriction. Therapy with intravenous vasopressors may be required in critically ill patients when efforts to optimize cardiac output and blood pressure with intravascular fluid therapy fail. Increasing systemic vascular resistance can promote a favorable perfusion pressure gradient to vital organs in critically ill patients with severe, unresponsive vasodilation. Improperly administered, vasopressors may impede cardiac output and reduce oxygen transport to vital tissue sites. The understanding of systemic and regional effects of vasopressors is currently evolving. Recent literature of the commonly used agents is reviewed. Individual drugs, drug combinations, and potential new therapies are discussed. (Vet. Emerg. & Crit. Care, 10:19,33, 2000) [source] Alternative strategies by thermophilic ants to cope with extreme heat: individual versus colony level traitsOIKOS, Issue 1 2000Xim Cerdá Cataglyphis is a fairly homogeneous ant genus which is widespread over the arid regions of the Old World. All Cataglyphis species are thermal specialists which are adapted to extreme environments where they forage at nearly lethal temperatures. This study focusses on two Cataglyphis species which differ considerably in their physical caste systems. These species have developed two alternative mechanisms facing extreme heat. In C. velox, foraging at high surface temperatures is clearly dependent on size: large C. velox workers forage at midday and are able to withstand higher temperatures than small workers. On the other hand, C. rosenhaueri has not developed great physical specialization, but the workers of this species have achieved physiological (such as low cuticular transpiration and metabolic rate), and behavioural adaptations (such as raising their abdomen to protect the vital organs contained in it from high temperatures) to tolerate thermal stress. The result is that small C. rosenhaueri workers may withstand extreme heat conditions in a similar way to large C. velox workers, and much better than small C. velox workers. The different mechanisms used by these two species to withstand extreme heat could reflect fundamental patterns of independent evolution. In some situations, selection may act to promote a relatively narrow size range of adult workers, all of them able to withstand thermal extremes, while in others it may act by producing different worker sizes with different tolerance to environmental conditions. [source] Bioengineered tissues: the science, the technology, and the industryORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2005T Ahsan Structured Abstract Authors ,, Ahsan T, Nerem RM Objective ,, The bioengineering of tissues and organs, sometimes called tissue engineering and at other times regenerative medicine, is emerging as a science, as a technology, and as an industry. The goal is the repair, replacement, and/or the regeneration of tissues and organs. The objective of this paper is to identify and discuss the major issues that have become apparent. Results ,, One of the critical issues is that of cell source, i.e. what will be the source of the cells to be employed? Another critical issue is the development of approaches for the fabrication of substitute tissues/organs and/or vehicles for the delivery of biological active molecules for use in the repair/regeneration of tissues. A third critical issue, one very much related to cell source, is that of immune acceptance. In addition, there are technological hurdles; there are additional issues such as the scale-up of manufacturing processes and the preservation of living-cell products for off-the-shelf availability. Although the initial products have been superficially applied skin substitutes, as this fledgling industry continues to evolve, it is beginning to focus on a wider range of more invasive and complicated products. From a public health perspective, the real opportunity may be in addressing chronic diseases, as well as the transplantation crisis (i.e. the tremendous disparity between patient need for vital organs and donor availability) and, equally important is the challenge of neural repair. Conclusion ,, These are the grand challenges, and the scientific community, business/private sector, and federal government must mobilize itself together in this emerging area to translate the benchtop science to the patient bedside. [source] IL-4,/, mice with lethal Mesocestoides corti infections , reduced Th2 cytokines and alternatively activated macrophagesPARASITE IMMUNOLOGY, Issue 12 2009A. E. O'CONNELL Summary Protection against Mesocestoides corti, a cestode that invades vital organs, is dependent on the production of IL-4, as IL-4,/, mice were found to have higher parasite burdens when compared with wild-type mice. The goal of this study was to investigate the role of IL-4 in immunity to M. corti, focusing on the immunological profile and on potential mediators of pathology. IL-4,/, mice infected with M. corti showed 100% mortality by 32 days, whereas wild-type mice survived for approximately 1 year. Parasite burdens were significantly increased in the liver, peritoneal, and thoracic cavities of IL-4,/, mice, associated with impaired recruitment of inflammatory cells and a reduction in monocytes and macrophages. IL-5 production by splenocytes and expression in liver tissue was decreased in infected IL-4,/, mice compared with wild-type mice. In contrast, IL-4,/, mice produced increased amounts of IFN, and TNF,. Alternatively activated macrophages were a major feature of liver granulomas in wild-type mice evidenced by Arginase I expression, while livers from infected IL-4,/, mice showed impaired alternative macrophage activation without increased classical macrophage activation. Thus, lethality during M. corti infection of IL-4,/, mice is associated with decreased Th2 cytokines, increased Th1 cytokines and impairment of alternatively activated macrophages. [source] Maternal capital and the metabolic ghetto: An evolutionary perspective on the transgenerational basis of health inequalitiesAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2010Jonathan C.K. Wells There is particular interest in understanding socioeconomic and ethnic variability in health status. The developmental origins of disease hypothesis emphasize the importance of growth patterns across the life-course in relation to noncommunicable disease risk. The physiological components of cardiovascular risk, collectively termed the metabolic syndrome, derive in part from a disparity between the homeostatic "metabolic capacity" of vital organs and the "metabolic load" induced by large tissue masses, a rich diet and sedentary behavior. From an evolutionary perspective, the risk of such disparity is decreased by maternal physiology regulating offspring growth trajectory during gestation and lactation. Maternal capital, defined as phenotypic resources enabling investment in the offspring, allows effective buffering of the offspring from nutritional perturbations and represents the environmental niche initially occupied by the offspring. Offspring growth patterns are sensitive to the magnitude of maternal capital during early windows of plasticity. Offspring life-history strategy can then respond adaptively to further factors across the life-course, but only within the context of this initial maternal influence on growth. Maternal somatic capital is primarily gained or lost across generations, through variable rates of fetal and infant growth. I argue that the poor nutritional experience of populations subjected to colonialism resulted in a systematic loss of maternal capital, reflected in downward secular trends in stature. Accelerating the recovery of somatic capital within generations overloads metabolic capacity and exacerbates cardiovascular risk, reflected in increased disease rates in urbanizing and emigrant populations. Public health policies need to benefit metabolic capacity without exacerbating metabolic load. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Reproduction in male rats is vulnerable to treatment with the flavonoid-rich seed extracts of Vitex negundoPHYTOTHERAPY RESEARCH, Issue 1 2004Suwagmani Das Abstract A partially puri,ed ,avonoid-rich extract was prepared from the seed of Vitex negundo. The effect of this extract on the reproductive system of male rats was investigated at four different concentrations. All the major accessory sex organs shed weight when the preparation was administered at doses of ,15 mg/rat/day after 15 days of treatment. The drop in weight was also re,ected in disturbed tissue biochemistry. Secretory products such as citric acid in the prostate, fructose in seminal vesicles and epididymal , -glucosidase activity, indices of accessory sex organ function in males, diminished. Microscopic examination of the sperm derived from the cauda epididymides of treated animals showed only a marginal change in vitality. However, sperm numbers dwindled and slackness in their motility was observed, factors that may impede fertility. Toxicity testing in blood did not point to distress in any of the vital organs. Taken together, it is inferred that the seed extracts of V. negundo interfere with male reproductive function without producing adverse toxicity in other vital organs. Copyright © 2004 John Wiley & Sons, Ltd. [source] The cardiovascular challenge of exercising in the heatTHE JOURNAL OF PHYSIOLOGY, Issue 1 2008José González-Alonso Exercise in the heat can pose a severe challenge to human cardiovascular control, and thus the provision of oxygen to exercising muscles and vital organs, because of enhanced thermoregulatory demand for skin blood flow coupled with dehydration and hyperthermia. Cardiovascular strain, typified by reductions in cardiac output, skin and locomotor muscle blood flow and systemic and muscle oxygen delivery accompanies marked dehydration and hyperthermia during prolonged and intense exercise characteristic of many summer Olympic events. This review focuses on how the cardiovascular system is regulated when exercising in the heat and how restrictions in locomotor skeletal muscle and/or skin perfusion might limit athletic performance in hot environments. [source] Comparison of Perfusion Quality in Hollow-Fiber Membrane Oxygenators for Neonatal Extracorporeal Life SupportARTIFICIAL ORGANS, Issue 4 2010Jonathan Talor Abstract Perfusion quality is an important issue in extracorporeal life support (ECLS); without adequate perfusion of the brain and other vital organs, multiorgan dysfunction and other deficits can result. The authors tested three different pediatric oxygenators (Medos Hilite 800 LT, Medtronic Minimax Plus, and Capiox Baby RX) to determine which gives the highest quality of perfusion at flow rates of 400, 600, and 800 mL/min using human blood (36°C, 40% hematocrit) under both nonpulsatile and pulsatile flow conditions. Clinically identical equipment and a pseudo-patient were used to mimic operating conditions during neonatal ECLS. Traditionally, the postoxygenator surplus hemodynamic energy value (SHEpost, extra energy obtained through pulsatile flow) is the one relied upon to give a qualitative determination of the amount of perfusion in the patient; the authors also examined SHE retention through the membrane, as well as the contribution of SHEpost to the postoxygenator total hemodynamic energy (THEpost). At each experimental condition, pulsatile flow outperformed nonpulsatile flow for all factors contributing to perfusion quality: the SHEpost values for pulsatile flow were 4.6,7.6 times greater than for nonpulsatile flow, while the THEpost remained nearly constant for pulsatile versus nonpulsatile flow. For both pulsatile and nonpulsatile flow, the Capiox Baby RX oxygenator was found to deliver the highest quality of perfusion, while the Minimax Plus oxygenator delivered the least perfusion. It is the authors' recommendation that the Baby RX oxygenator running under pulsatile flow conditions be used for pediatric ECLS, but further studies need to be done in order to establish its effectiveness beyond the FDA-approved time span. [source] Intrinsic Toxicity of Hemoglobin: How to Counteract ItARTIFICIAL ORGANS, Issue 2 2009Jan Simoni Abstract The development of safe and effective blood substitutes is of great importance in both civilian and military medicine. The currently tested hemoglobin (Hb)-based oxygen carriers, however, have toxicity and efficacy problems. A number of unwanted effects have been observed in human trials, creating doubts about their clinical usefulness. In some subjects, vasoconstriction and decreased blood flow to the vital organs, heart attack, stroke, systemic inflammation, organ damage, and even death, have been attributed to the transfusion of these experimental products. Hb is a well-known pressor agent and strong oxidant, although the full understanding of its intrinsic toxicity is yet to be uncovered. In particular, the complete mechanism of Hb-induced vasoconstriction needs full elucidation. Knowledge of the biological events that trigger the induction of genes upon treatment with redox-active Hb, as well as its catabolism, is still incomplete. It seems that our limited knowledge of free Hb effects in vivo is the main reason for not yet having a viable substitute of human blood. The future for universal red cell substitutes is in the new-generation products that address all of Hb's intrinsic toxicity issues. [source] Ultrafiltration and Dry Weight,What Are the Cardiovascular Effects?ARTIFICIAL ORGANS, Issue 3 2003Article first published online: 2 APR 200, Bernd G. Stegmayr Abstract: Long-term prognosis in dialysis is poor compared to that in healthy control persons. A worsening of the prognosis is noted especially for patients who at initiation of dialysis have congestive heart failure, ischemic heart disease, or left ventricular dysfunction or hypertrophy. This is the main reason that cardiovascular causes are the most common for morbidity in these patients. The weight obtained when normal urine output is present is the dry weight. With reduced ability to excrete the volume by the kidneys in end-stage renal disease (ESRD), the body will retain water and the patient will gain weight. This extra weight is due to volume overload. While volume overload may induce a rise in blood pressure, if the heart is in acceptable condition, a fast removal of fluid by ultrafiltration (UF) during dialysis may instead cause hypotension. Ultrafiltration failure in peritoneal dialysis (PD) patients may lead to successive water retention and overhydration with subsequent cardiac failure, while volume overload may occur over a few days in hemodialysis (HD) patients. Anemia or even too-high hematocrit may impair cardiac function further and worsen conditions caused by wrong dry weight. Thus, during long-term and sustained volume overload, left ventricular (LV) hypertrophy will occur in an eccentric manner. A sustained overload then may lead to cell death and LV dilatation and, eventually, systolic dysfunction. Once a severe left ventricular dilatation has developed, the blood pressure may decrease during volume overload. A worsened prognosis is seen if malnutrition and low albumin levels are present. Volume overload necessitates ultrafiltration to achieve dry weight. Thereby, volume contraction contributes to exaggerated stimulation of or response to activation of the RAS and alpha-adrenergic sympathetic systems. If ultrafiltration goes beyond these compensatory mechanisms, hypotension will occur and increase the risk for hypoperfusion of vital organs. Such episodes may cause cardiac morbidity, aspiration pneumonia, vascular access closure, or neurological complications (seizures, cerebral infarction), besides a more rapid lowering of residual renal function. Preventive measures are, first, finding the right dry weight; second, minimizing interdialytic weight gain; third, optimizing the target for hemoglobin (110,120 g/l); fourth, lowering dialysate calcium (1.25 mmol/l); and fifth, eventually using higher dialysate potassium if long dialyses are performed. [source] Over-expression of cysteine proteinase inhibitor cystatin 6 promotes pancreatic cancer growthCANCER SCIENCE, Issue 8 2008Masayo Hosokawa Pancreatic ductal adenocarcinoma (PDAC) shows the worst mortality among the common malignancies and development of novel therapies for PDAC through identification of good molecular targets is an urgent issue. Among dozens of over-expressing genes identified through our gene-expression profile analysis of PDAC cells, we here report CST6 (Cystatin 6 or E/M) as a candidate of molecular targets for PDAC treatment. Reverse transcriptase,polymerase chain reaction (RT-PCR) and immunohistochemical analysis confirmed over-expression of CST6 in PDAC cells, but no or limited expression of CST6 was observed in normal pancreas and other vital organs. Knock-down of endogenous CST6 expression by small interfering RNA attenuated PDAC cell growth, suggesting its essential role in maintaining viability of PDAC cells. Concordantly, constitutive expression of CST6 in CST6-null cells promoted their growth in vitro and in vivo. Furthermore, the addition of mature recombinant CST6 in culture medium also promoted cell proliferation in a dose-dependent manner, whereas recombinant CST6 lacking its proteinase-inhibitor domain and its non-glycosylated form did not. Over-expression of CST6 inhibited the intracellular activity of cathepsin B, which is one of the putative substrates of CST6 proteinase inhibitor and can intracellularly function as a pro-apoptotic factor. These findings imply that CST6 is likely to involve in the proliferation and survival of pancreatic cancer probably through its proteinase inhibitory activity, and it is a promising molecular target for development of new therapeutic strategies for PDAC. (Cancer Sci 2008; 99: 1626,1632) [source] | |||||||||||||