Thumbnail sampler of 10 diverse physiology papers from IUPS 2005

04/03/05

San Diego (April 4, 2005) – Below are thumbnail sketches of 10 research presentations from the 35th Congress of the International Union of Physiological Sciences held in San Diego, March 31-April 5.

Abstracts for all presentations may be accessed through a complete searchable online program at http://www.faseb.org/meetings/eb2005/call/default.htm covering both IUPS and Experimental Biology 2005, which is being held concurrently.

"Temperature-dependent cadmium effects on whole animal and mitochondrial metabolism of the eastern oyster Crassostrea virginica."

Gisela Lannig, Inna Sokolova. Biological Department, University of North Carolina at Charlotte. Physiology 138.12

The researchers found that increased susceptibility of oysters to trace metal pollution at high temperature suggests that global warming can post a deadly threat for populations in polluted areas because previously non-toxic concentrations may become toxic and fatal with warming. Next step will be to study to what extent metal pollution reduces temperature tolerance limits of oysters and to apply that knowledge to study other ectothermic animals.

Supported by the Alexander von Humboldt Foundation and National Science Foundation.

"Maturation and functional restoration of DeltaF508CFTR by its subdomains in cystic fibrosis airway cells."

Fei Sun, Steven B Condliff, Carol A Bertrand, Zhibao Mi, Joseph M Pilewski, Paul D Robbins, Robert J Bridges, Raymond A Frizzell. Cell Biology and Physiology, University of Pittsburgh. Physiology 349.3. Featured topic 340: "Molecular basis of epithelial disease."

Cystic fibrosis is the most common fatal genetic disease among Caucasians, with about 30,000 CF patients in North America. Researchers tested the notion that introducing a fragment of mutant CFTR (cystic fibrosis transmembrane conductance regulator) would compete for chaperone binding to the full-length mutant and thereby limit its degradation. Their findings indicate that chaperone competition can rescue delta-F508CFTR from destruction, permitting its channel activity to appear at the cell surface. Also, the delivery of mutant protein fragments may provide a therapy for CF.

"Dietary interventions reduce muscle weakness in unloaded muscle."

Sandrine Arbogast1, Ann R. Kennedy2, Michael B. Reid1. 1Dept of Physiology, University of Kentucky, 2Dept of Radiation Oncology, University of Pennsylvania. Physiology 347.5. Featured topic session #659: "Mosso and muscle fatigue: 116 years after the 1st Congress of Physiology."

Whether it's an astronaut in space for a long time or an elderly person recovering from hip surgery, leg muscles get smaller and weaker, and the person has difficulty standing or walking. The muscle wasting is associated with an increase in free radical production and protein breakdown. Using mice unable to put force on their hind legs, researchers tested two diets: 1% Bowman-Birk inhibitor concentrate (a protease inhibitor made from soybeans) and the second a mixture of antioxidants. They found that while neither diet prevented muscle wasting, both diets lessened the weakness caused by the "unloading."

Funding: National Space Biomedical Research Institute and NIH grant.

"Expression profile of EphA receptors after spinal cord injury in adult rats."

Lillian Cruz-Orengo1, Johnny Davis Figueroa1, Ixane Velázquez1, Margarita Irizarry-Ramírez1, Christopher A Willson2, Hope Jones2, Scott R Whittemore2, Jorge David Miranda1. 1Physiology, UPR School of Medicine, San Juan, Puerto Rico, 2Neurological Surgery, University of Louisville School of Medicine, Kentucky Spinal Cord Injury Research Center Neurological Surgery. Physiology 924.3. Featured topic session #895: "Long-term plasticity and SCI."

Researchers are looking at molecular activities that occur early in development that "come back" after trauma, such as a spinal cord lesion. They observed such genetic "reexpression" in spinal cord injury. Knowing the expression profile of EphA3, A4 and A7 receptors, they are looking at their specific contribution toward regeneration. When they "shut down" the three receptors effect at the same time they observed a better locomotor activity at the acute phase of animal recovery.

Funding: NIH (SNRP, others), State of Kentucky (KSCHIRT), Norton Health Care, American Psychological Association

"Exercise Increases Soluble Vascular Endothelial Growth Factor Receptor-1 (sFlt-1) in Circulation of Healthy Volunteers."

Amelia Purser Bailey, Megan Shparago, Jian-Wei Gu. Physiology & Biophysics, University of Mississippi Medical Center. Physiology 348.4. Featured topic session #770: "Muscle as an endocrine organ."

Physical inactivity a well-established risk factor for cancer, but the molecular mechanisms are unclear. The researchers found that exercise-induced circulating sFlt-1 was associated with a decrease in unbound circulating VEGF. The function of sFlt-01 is to bind to VEGF to block its activity as one the most potent stimulators of blood vessel growth under physiological and pathological conditions. Formation of new blood vessels is a key pathogenic step for development of cancer and atherosclerosis.

"Pulmonary Functome Revealed by Transcriptomes of Six Rat Organs." Zhongming Chen, Jiwang Chen, Tingting Weng, Lin Liu. Physiological Sciences, Oklahoma State University. Physiology 936.5.

Researchers compared normal transcriptomes of rat lung, heart, kidney, liver, spleen and brain on one DNA microarray slide. This novel hybridization system was three times more efficient and significantly more reproducible than standard hybridization. Among the most abundant genes, cd37, ly6a and cathepsin Y haven't been studied in the lung. Their high and specific expression in the pulmonary system imply their potentially important roles.

Funding: NIH (LL), and an American Heart Association pre-doctoral fellowship (ZC)

"Sex Hormones: A Big Player in the Spontaneous Activity of Female but Not Male Rats."

Andrea M Foley1, Rebecca A Duckworth1,2, Marybeth Brown1,3. 1Physical Therapy, University of Missouri, Physical Therapy Dept., 2Biomedical Sciences, 3Center for Gender Physiology. Physiology 347.9.

As people age, sex hormones decline and so does exercise. Researchers found that testosterone replacement had no effect on spontaneous activity, whereas estrogen did. Identifying gender differences and fctors affecting our activity could lead to a better understanding of an aging population. Next they will attempt to determine if the estrogen improved spontaneous activity through behavior, a local muscle-specific response or a combination.

Funding: NASA and National Institute of Aging.

"Estrogen Increases Mitochondrial Efficiency in Cerebral Blood Vessels."

Chris Stirone1, Vincent Procaccio2, Sue P. Duckles1, Diana N. Krause1. 1Department of Pharmacology, College of Medicine, University of California, Irvine, 2Center for Molecular and Mitochondrial Medicine and Genetics. Physiology 909.18.

UCI researchers show for first time that estrogen has an effect on mitochondria in the cells of blood vessels, specifically blood vessels from the brain. They also showed estrogen receptors in the mitochondria. They found that after estrogen treatment, the mitochondria could produce energy more efficiently with lower amounts of damaging free radicals – a problem during aging. They believe that the novel mechanism of estrogen action may help explain why pre-menopausal women have a lower incidence of stoke than men of the same age.

Funding: NIH

"PKC beta/Egr-1: a crucial axis in atherosclerosis."

Evis Harja, Barry I Hudson, Yu Shan Zou, Yan Lu, Ann Marie Schmidt, Shi-Fang Yan. Division of Surgical Science, Columbia University, New York City. Physiology 387.2.

Researchers tested the hypothesis that Protein Kinase C-beta is a key modulator of atherogenesis in a hyperlipidemic environment. They found that mice lacking both apolipoprotein E (ApoE) and PKC beta II displayed significantly decreased atherosclerosis. To test if this was due to deletion of PKC beta they tested an inhibitor of this enzyme. The fed ApoE null mice with chow containing the PCK beta inhibitor ruboxistaurin, or vehicle chow. Compared to mice receiving vehicle chows, mice fed ruboxistaurin displayed significantly decreased atherosclerosis. Taken together the findings highlight key roles for PKC beta in atherosclerosis development. The studies suggest that atherosclerosis may be affected by the inhibitor of the protein, ruboxistaurin, which is in clinical trials.

"Chronic secondary hypertension during pregnancy: impact on maternal renal function."

Devaki Maduwegedera, Rebecca L Flower, Kate M Denton, Monash University, Department of Physiology, Melbourne, Australia. Physiology 703.6.

Researchers wanted to study whether inadequate maternal kidney function in pregnancy might contribute to the fetal programming of adult hypertension. To start, they determined kidney function before and after nitric oxide blockade. The found that renal function was not different between normotensive pregnant and nulliparious (never pregnant) groups. However, after pregnancy in hypertensive rabbits, renal function was reduced by 25% in a damaged kidney, but increased 25% in the non-damaged kidney. So there was no change in total kidney function, but during pregnancy plasma creatinine levels were significantly increased, suggesting that kidney function may have been further compromised. They also found that the damaged kidney didn't appear to produce nitric oxide; if so, this may account for the further reduction in kidney function in the hypertensive group during pregnancy. They speculate that kidney dysfunction in this model of pregnancy and hypertension may be a stimulus altering fetal development.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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