Life Sciences Commons^™

Invited Review: Adrenocortical Function In Avian And Non-Avian Reptiles: Insights From Dispersed Adrenocortical Cells., Rocco V. Carsia, Patrick J. Mcilroy, Henry B John-Alder

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

Herein we review our work involving dispersed adrenocortical cells from several lizard species: the Eastern Fence Lizard (Sceloporus undulatus), Yarrow's Spiny Lizard (Sceloporus jarrovii), Striped Plateau Lizard (Sceloporus virgatus) and the Yucatán Banded Gecko (Coleonyx elegans). Early work demonstrated changes in steroidogenic function of adrenocortical cells derived from adult S. undulatus associated with seasonal interactions with sex. However, new information suggests that both sexes operate within the same steroidogenic budget over season. The observed sex effect was further explored in orchiectomized and ovariectomized lizards, some supported with exogenous testosterone. Overall, a suppressive effect of testosterone was evident, especially in cells …

Role Of Chronic Stress-Induced Neuroinflammation In Rodent Locus Coeruleus Physiology And Anxiety-Like Behaviors, Arthur Anthony Alfonso Reyes

Graduate School of Biomedical Sciences Theses and Dissertations

The locus coeruleus (LC), the primary site of brain norepinephrine (NE), is a key anatomical brain region implicated in the stress response. Stress is a neuroendocrine physiologic response to a stressor that promotes organism survival through adaptive change and restoration of homeostasis. The central stress response, which drives behavioral and physiological change, is primarily mediated by activating the hypothalamic-pituitary-adrenal (HPA) axis. While advantageous in the short term, chronic stress exposure can lead to HPA axis and LC dysregulation, which are thought to contribute to the etiology of anxiety disorders. Previous studies demonstrate the effects of acute stress in increasing LC …

Reduced Mitochondrial Dna And Oxphos Protein Content In Skeletal Muscle Of Children With Cerebral Palsy, Ferdinand Von Walden, Ivan J. Vechetti Jr., Davis A. Englund, Vandré C. Figueiredo, Rodrigo Fernandez-Gonzalo, Kevin A. Murach, Jessica Pingel, John J. Mccarthy, Per Stål, Eva Pontén

Physiology Faculty Publications

AIM: To provide a detailed gene and protein expression analysis related to mitochondrial biogenesis and assess mitochondrial content in skeletal muscle of children with cerebral palsy (CP).

METHOD: Biceps brachii muscle samples were collected from 19 children with CP (mean [SD] age 15y 4mo [2y 6mo], range 9-18y, 16 males, three females) and 10 typically developing comparison children (mean [SD] age 15y [4y], range 7-21y, eight males, two females). Gene expression (quantitative reverse transcription polymerase chain reaction [PCR]), mitochondrial DNA (mtDNA) to genomic DNA ratio (quantitative PCR), and protein abundance (western blotting) were analyzed. Microarray data sets (CP/aging/bed rest) were …

Chronic Muscle Weakness And Mitochondrial Dysfunction In The Absence Of Sustained Atrophy In A Preclinical Sepsis Model, Allison M. Owen, Samir P. Patel, Jeffrey D. Smith, Beverly K. Balasuriya, Stephanie F. Mori, Gregory S. Hawk, Arnold J. Stromberg, Naohide Kuriyama, Masao Kaneki, Alexander G. Rabchevsky, Timothy A. Butterfield, Karyn A. Esser, Charlotte A. Peterson, Marlene E. Starr, Hiroshi Saito

Physiology Faculty Publications

Chronic critical illness is a global clinical issue affecting millions of sepsis survivors annually. Survivors report chronic skeletal muscle weakness and development of new functional limitations that persist for years. To delineate mechanisms of sepsis-induced chronic weakness, we first surpassed a critical barrier by establishing a murine model of sepsis with ICU-like interventions that allows for the study of survivors. We show that sepsis survivors have profound weakness for at least 1 month, even after recovery of muscle mass. Abnormal mitochondrial ultrastructure, impaired respiration and electron transport chain activities, and persistent protein oxidative damage were evident in the muscle of …

Post-Acquisition Processing Confounds In Brain Volumetric Quantification Of White Matter Hyperintensities, Ahmed A. Bahrani, Omar M. Al-Janabi, Erin L. Abner, Shoshana H. Bardach, Richard J. Kryscio, Donna M. Wilcock, Charles D. Smith, Gregory A. Jicha

Neurology Faculty Publications

BACKGROUND: Disparate research sites using identical or near-identical magnetic resonance imaging (MRI) acquisition techniques often produce results that demonstrate significant variability regarding volumetric quantification of white matter hyperintensities (WMH) in the aging population. The sources of such variability have not previously been fully explored.

NEW METHOD: 3D FLAIR sequences from a group of randomly selected aged subjects were analyzed to identify sources-of-variability in post-acquisition processing that can be problematic when comparing WMH volumetric data across disparate sites. The methods developed focused on standardizing post-acquisition protocol processing methods to develop a protocol with less than 0.5% inter-rater variance.

RESULTS: A series …

Transcranial Direct Current Stimulation Of Motor Cortex Enhances Running Performance., Seung-Bo Park, Dong Jun Sung, Bokyung Kim, Sojung Kim, Joung-Kyue Han

Faculty Scholarship for the College of Science & Mathematics

Transcranial direct current stimulation (tDCS) is a technique used to modulate neuronal excitability through non-invasive brain stimulation that can enhance exercise performance. We hypothesize that tDCS would improve submaximal running time to exhaustion (TTE) and delay the increase in the rating of perceived exertion (RPE) over time. We also hypothesize that tDCS would not lead to difference in cardiorespiratory responses. We employed a randomized, single-blinded, and counterbalanced design in which 10 trained men participated. After receiving either 20 min of 1.98 mA anodal tDCS applied over the primary motor cortex (M1) or sham-operated control on separate days, participants completed a …

Associative Learning Contributes To The Increased Water Intake Observed After Daily Injections Of Angiotensin Ii, Maggie Postolache, Jessica Santollo, Derek Daniels

Biology Faculty Publications

Daily injections of angiotensin II (AngII) cause a progressive increase of water intake that resembles a classically ascribed non-associative sensitization. Consistent with the presumption that the observed increase in intake was sensitization, we hypothesized that it resulted from a pharmacological interaction between AngII and its receptor. To test this hypothesis, and remove the influence of drinking itself, we implemented a delay in water access after injection of AngII (icv) on four consecutive ‘induction days,’ and then measured intake on the next day (‘test day’) when rats were allowed to drink immediately after AngII. The delay in water access effectively reduced …

Alzheimer's Disease Genetics And Abca7 Splicing, Jared B. Vasquez, James F. Simpson, Ryan Harpole, Steven Estus

Physiology Faculty Publications

Both common and rare polymorphisms within ABCA7 have been associated with Alzheimer’s disease (AD). In particular, the rare AD associated polymorphism rs200538373 was associated with altered ABCA7 exon 41 splicing and an AD risk odds ratio of ∼1.9. To probe the role of this polymorphism in ABCA7 splicing, we used minigene studies and qPCR of human brain RNA. We report aberrant ABCA7 exon 41 splicing in the brain of a carrier of the rs200538373 minor C allele. Moreover, minigene studies show that rs200538373 acts as a robust functional variant in vitro. Lastly, although the ABCA7 isoform with an extended …

Using A Respiratory Navigator Significantly Reduces Variability When Quantifying Left Ventricular Torsion With Cardiovascular Magnetic Resonance, Sean M. Hamlet, Christopher M. Haggerty, Jonathan D. Suever, Gregory J. Wehner, Kristin N. Andres, David K. Powell, Richard J. Charnigo, Brandon K. Fornwalt

Electrical and Computer Engineering Faculty Publications

Background: Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic resonance (CMR) based quantification of LV torsion.

Methods: We assessed respiratory-related variability in measured LV torsion with two distinct experimental protocols. First, 17 volunteers were recruited for CMR with cine displacement encoding with stimulated echoes (DENSE) in which a respiratory navigator was used to measure …

Reduced Skeletal Muscle Satellite Cell Number Alters Muscle Morphology After Chronic Stretch But Allows Limited Serial Sarcomere Addition, Matthew C. Kinney, Sudarshan Dayanidhi, Peter B. Dykstra, John J. Mccarthy, Charlotte A. Peterson, Richard L. Lieber

Physiology Faculty Publications

Introduction: Muscles add sarcomeres in response to stretch, presumably to maintain optimal sarcomere length. Clinical evidence from patients with cerebral palsy, who have both decreased serial sarcomere number and reduced satellite cells (SCs), suggests a hypothesis that SCs may be involved in sarcomere addition. Methods: A transgenic Pax7‐DTA mouse model underwent conditional SC depletion, and their soleii were then stretch‐immobilized to assess the capacity for sarcomere addition. Muscle architecture, morphology, and extracellular matrix (ECM) changes were also evaluated. Results: Mice in the SC‐reduced group achieved normal serial sarcomere addition in response to stretch. However, muscle fiber cross‐sectional …

Myocardial Relaxation Is Accelerated By Fast Stretch, Not Reduced Afterload, Charles S. Chung, Charles W. Hoopes, Kenneth S. Campbell

Physiology Faculty Publications

Fast relaxation of cross-bridge generated force in the myocardium facilitates efficient diastolic function. Recently published research studying mechanisms that modulate the relaxation rate has focused on molecular factors. Mechanical factors have received less attention since the 1980s when seminal work established the theory that reducing afterload accelerates the relaxation rate. Clinical trials using afterload reducing drugs, partially based on this theory, have thus far failed to improve outcomes for patients with diastolic dysfunction. Therefore, we reevaluated the protocols that suggest reducing afterload accelerates the relaxation rate and identified that myocardial relengthening was a potential confounding factor. We hypothesized that the …

Repeated Closed Head Injury In Mice Results In Sustained Motor And Memory Deficits And Chronic Cellular Changes, Amanda Nicholle Bolton Hall, Binoy Joseph, Jennifer M. Brelsfoard, Kathryn E. Saatman

Spinal Cord and Brain Injury Research Center Faculty Publications

Millions of mild traumatic brain injuries (TBIs) occur every year in the United States, with many people subject to multiple head injuries that can lead to chronic behavioral dysfunction. We previously reported that mild TBI induced using closed head injuries (CHI) repeated at 24h intervals produced more acute neuron death and glial reactivity than a single CHI, and increasing the length of time between injuries to 48h reduced the cumulative acute effects of repeated CHI. To determine whether repeated CHI is associated with behavioral dysfunction or persistent cellular damage, mice receiving either five CHI at 24h intervals, five CHI at …

Diffuse Traumatic Brain Injury Induces Prolonged Immune Sysregulation And Potentiates Hyperalgesia Following A Peripheral Immune Challenge, Rachel K. Rowe, Gavin I. Ellis, Jordan L. Harrison, Adam D. Bachstetter, Gregory F. Corder, Linda J. Van Eldik, Bradley K. Taylor, Francesc Marti, Jonathan Lifshitz

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Background: Nociceptive and neuropathic pain occurs as part of the disease process after traumatic brain injury (TBI) in humans. Central and peripheral inflammation, a major secondary injury process initiated by the traumatic brain injury event, has been implicated in the potentiation of peripheral nociceptive pain. We hypothesized that the inflammatory response to diffuse traumatic brain injury potentiates persistent pain through prolonged immune dysregulation.

Results: To test this, adult, male C57BL/6 mice were subjected to midline fluid percussion brain injury or to sham procedure. One cohort of mice was analyzed for inflammation-related cytokine levels in cortical biopsies and serum along an …

Where Are You Looking? Pseudogaze In Afterimages, Daw-An Wu, Patrick Cavanagh

Dartmouth Scholarship

How do we know where we are looking? A frequent assumption is that the subjective experience of our direction of gaze is assigned to the location in the world that falls on our fovea. However, we find that observers can shift their subjective direction of gaze among different nonfoveal points in an afterimage. Observers were asked to look directly at different corners of a diamond-shaped afterimage. When the requested corner was 3.5° in the periphery, the observer often reported that the image moved away in the direction of the attempted gaze shift. However, when the corner was at 1.75° eccentricity, …

Myonuclear Transcription Is Responsive To Mechanical Load And Dna Content But Uncoupled From Cell Size During Hypertrophy, Tyler J. Kirby, Rooshil M. Patel, Timothy S. Mcclintock, Esther E. Dupont-Versteegden, Charlotte A. Peterson, John J. Mccarthy

Physiology Faculty Publications

Myofibers increase size and DNA content in response to a hypertrophic stimulus, thus providing a physiological model with which to study how these factors affect global transcription. Using 5-ethynyl uridine (EU) to metabolically label nascent RNA, we measured a sevenfold increase in myofiber transcription during early hypertrophy before a change in cell size and DNA content. The typical increase in myofiber DNA content observed at the later stage of hypertrophy was associated with a significant decrease in the percentage of EU-positive myonuclei; however, when DNA content was held constant by preventing myonuclear accretion via satellite cell depletion, both the number …

Mechanical Conflict System: A Novel Operant Method For The Assessment Of Nociceptive Behavior, Steven E. Harte, Jessica B. Meyers, Renee R. Donahue, Bradley K. Taylor, Thomas J. Morrow

Physiology Faculty Publications

A new operant test for preclinical pain research, termed the Mechanical Conflict System (MCS), is presented. Rats were given a choice either to remain in a brightly lit compartment or to escape to a dark compartment by crossing an array of height-adjustable nociceptive probes. Latency to escape the light compartment was evaluated with varying probe heights (0, .5, 1, 2, 3, and 4 mm above compartment floor) in rats with neuropathic pain induced by constriction nerve injury (CCI) and in naive control rats. Escape responses in CCI rats were assessed following intraperitoneal administration of pregabalin (10 and 30 mg/kg), morphine …

Modulating Foveal Representation Can Influence Visual Discrimination In The Periphery, Qing Yu, Won Mok Shim

Dartmouth Scholarship

A previous study by Williams et al. (2008) provided evidence for a novel form of feedback in the visual system, whereby peripheral information is contained in foveal retinotopic cortex. Beyond its possible implication for peripheral object recognition, few studies have examined the effect of a direct behavioral manipulation of the foveal feedback representation. To address this question, we measured participants' peripheral visual discrimination performance while modulating their foveal representation in a series of psychophysical experiments. On each trial, participants discriminated the identities of briefly presented novel, three-dimensional objects or the orientations of gratings in a peripheral location while fixating at …

Mw151 Inhibited Il-1Β Levels After Traumatic Brain Injury With No Effect On Microglia Physiological Responses, Adam D. Bachstetter, Zhengqiu Zhou, Rachel K. Rowe, Bin Xing, Danielle S. Goulding, Alyssa N. Conley, Pradoldej Sompol, Shelby Meier, Jose F. Abisambra, Jonathan Lifshitz, D. Martin Watterson, Linda J. Van Eldik

Sanders-Brown Center on Aging Faculty Publications

A prevailing neuroinflammation hypothesis is that increased production of proinflammatory cytokines contributes to progressive neuropathology, secondary to the primary damage caused by a traumatic brain injury (TBI). In support of the hypothesis, post-injury interventions that inhibit the proinflammatory cytokine surge can attenuate the progressive pathology. However, other post-injury neuroinflammatory responses are key to endogenous recovery responses. Therefore, it is critical that pharmacological attenuation of detrimental or dysregulated neuroinflammatory processes avoid pan-suppression of inflammation. MW151 is a CNS-penetrant, small molecule experimental therapeutic that restores injury- or disease-induced overproduction of proinflammatory cytokines towards homeostasis without immunosuppression. Post-injury administration of MW151 in a …

Gender Representation In The Vision Sciences: A Longitudinal Study, Emily A. Cooper, Ana Radonjic

Dartmouth Scholarship

Understanding the current status and historical trends of gender representation within a research field is an important component of fostering a diverse and inclusive scientific community. Here, we report on the gender representation of a large sample of the vision science research community—the attendees of the Annual Meeting of the Vision Sciences Society (VSS). Our analysis shows that the majority of scientists at all career levels in our sample are male. This imbalance is most pronounced for the senior scientists, whereas predoctoral students are nearly balanced between the genders. Historically, the gender imbalance was larger than it is at present, …

Serum Amyloid A Impairs The Antiinflammatory Properties Of Hdl, Chang Yeop Han, Chongren Tang, Myriam E. Guevara, Hao Wei, Tomasz Wietecha, Baohai Shao, Savitha Subramanian, Mohamed Omer, Shari Wang, Kevin D. O'Brien, Santica M. Marcovina, Thomas N. Wight, Tomas Vaisar, Maria C. De Beer, Frederick C. De Beer, William R. Osborne, Keith B. Elkon, Alan Chait

Physiology Faculty Publications

HDL from healthy humans and lean mice inhibits palmitate-induced adipocyte inflammation; however, the effect of the inflammatory state on the functional properties of HDL on adipocytes is unknown. Here, we found that HDL from mice injected with AgNO₃ fails to inhibit palmitate-induced inflammation and reduces cholesterol efflux from 3T3-L1 adipocytes. Moreover, HDL isolated from obese mice with moderate inflammation and humans with systemic lupus erythematosus had similar effects. Since serum amyloid A (SAA) concentrations in HDL increase with inflammation, we investigated whether elevated SAA is a causal factor in HDL dysfunction. HDL from AgNO₃-injected mice lacking Saa1.1 …

Genetic And Acute Cpeb1 Depletion Ameliorate Fragile X Pathophysiology, Tsuyoshi Udagawa, Natalie Farny, Mira Jakovcevski, Hanoch Kaphzan, Juan Alarcon, Shobha Anilkumar, Maria Ivshina, Jessica Hurt, Kentaro Nagaoka, Vijayalaxmi Nalavadi, Lori Lorenz, Gary Bassell, Schahram Akbarian, Sumantra Chattarji, Eric Klann, Joel Richter

Natalie G. Farny

Fragile X syndrome (FXS), the most common cause of inherited mental retardation and autism, is caused by transcriptional silencing of FMR1, which encodes the translational repressor fragile X mental retardation protein (FMRP). FMRP and cytoplasmic polyadenylation element-binding protein (CPEB), an activator of translation, are present in neuronal dendrites, are predicted to bind many of the same mRNAs and may mediate a translational homeostasis that, when imbalanced, results in FXS. Consistent with this possibility, Fmr1(-/y); Cpeb1(-/-) double-knockout mice displayed amelioration of biochemical, morphological, electrophysiological and behavioral phenotypes associated with FXS. Acute depletion of CPEB1 in the hippocampus of adult Fmr1(-/y) mice …

Rfx Transcription Factors Are Essential For Hearing In Mice, Ran Elkon, Beatrice Milon, Laura Morrison, Manan Shah, Sarath Vijayakumar, Manoj Racherla, Carmen C. Leitch, Lorna Silipino, Shadan Hadi, Michèle Weiss-Gayet, Emmanuèle Barras, Christoph D. Schmid, Aouatef Ait-Lounis, Ashley Barnes, Yang Song, David J. Eisenman, Efrat Eliyahu, Gregory I. Frolenkov, Scott E. Strome, Bénédicte Durand, Norann A. Zaghloul, Sherri M. Jones, Walter Reith, Ronna Hertzano

Physiology Faculty Publications

Sensorineural hearing loss is a common and currently irreversible disorder, because mammalian hair cells (HCs) do not regenerate and current stem cell and gene delivery protocols result only in immature HC-like cells. Importantly, although the transcriptional regulators of embryonic HC development have been described, little is known about the postnatal regulators of maturating HCs. Here we apply a cell type-specific functional genomic analysis to the transcriptomes of auditory and vestibular sensory epithelia from early postnatal mice. We identify RFX transcription factors as essential and evolutionarily conserved regulators of the HC-specific transcriptomes, and detect Rfx1,2,3,5 and 7 in the developing HCs. …

Validation Of Maximal Heart Rate Prediction Equations Based On Sex And Physical Activity Status, Stephen J. Roy, J.L. Mccrory

International Journal of Exercise Science

International Journal of Exercise Science 8(4): 318-330, 2015. The purpose of the study was to determine if measured maximal heart rate (HR_max) was affected by sex or aerobic training status, and to determine the accuracy of three common clinical age-prediction maximal heart rate regression equations used to predict HR_max: HR_max = 220 – age, HR_max = 226 – age, and HR_max = 208 – (0.7 ∙ age). Fifty-two participants in total, 30 of which were in the active group (15 M, 15 F) and 22 subjects in the sedentary group (9 M, …

Enhanced Nmda Receptor-Mediated Modulation Of Excitatory Neurotransmission In The Dorsal Vagal Complex Of Streptozotocin-Treated, Chronically Hyperglycemic Mice, Eva C. Bach, Katalin Cs. Halmos, Bret N. Smith

Physiology Faculty Publications

A variety of metabolic disorders, including complications experienced by diabetic patients, have been linked to altered neural activity in the dorsal vagal complex. This study tested the hypothesis that augmentation of N-Methyl-D-Aspartate (NMDA) receptor-mediated responses in the vagal complex contributes to increased glutamate release in the dorsal motor nucleus of the vagus nerve (DMV) in mice with streptozotocin-induced chronic hyperglycemia (i.e., hyperglycemic mice), a model of type 1 diabetes. Antagonism of NMDA receptors with AP-5 (100 μM) suppressed sEPSC frequency in vagal motor neurons recorded in vitro, confirming that constitutively active NMDA receptors regulate glutamate release in the DMV. There …

Smooth-Muscle Bmal1 Participates In Blood Pressure Circadian Rhythm Regulation, Zhongwen Xie, Wen Su, Shu Liu, Guogang Zhao, Karyn Esser, Elizabeth A. Schroder, Mellani Lefta, Harald M. Stauss, Zhenheng Guo, Ming Cui Gong

Physiology Faculty Publications

As the central pacemaker, the suprachiasmatic nucleus (SCN) has long been considered the primary regulator of blood pressure circadian rhythm; however, this dogma has been challenged by the discovery that each of the clock genes present in the SCN is also expressed and functions in peripheral tissues. The involvement and contribution of these peripheral clock genes in the circadian rhythm of blood pressure remains uncertain. Here, we demonstrate that selective deletion of the circadian clock transcriptional activator aryl hydrocarbon receptor nuclear translocator-like (Bmal1) from smooth muscle, but not from cardiomyocytes, compromised blood pressure circadian rhythm and decreased blood …

Over-Expression Of Copper/Zinc Superoxide Dismutase In The Median Preoptic Nucleus Attenuates Chronic Angiotensin Ii-Induced Hypertension In The Rat., John P. Collister, Mitch Bellrichard, Donna Drebes, David Nahey, Jun Tian, Matthew C. Zimmerman

Journal Articles: Cellular & Integrative Physiology

The brain senses circulating levels of angiotensin II (AngII) via circumventricular organs, such as the subfornical organ (SFO), and is thought to adjust sympathetic nervous system output accordingly via this neuro-hormonal communication. However, the cellular signaling mechanisms involved in these communications remain to be fully understood. Previous lesion studies of either the SFO, or the downstream median preoptic nucleus (MnPO) have shown a diminution of the hypertensive effects of chronic AngII, without providing a clear explanation as to the intracellular signaling pathway(s) involved. Additional studies have reported that over-expressing copper/zinc superoxide dismutase (CuZnSOD), an intracellular superoxide (O2·-) scavenging enzyme, in …

Cannabinoid Receptor 2 Agonist Attenuates Pain Related Behavior In Rats With Chronic Alcohol/High Fat Diet Induced Pancreatitis, Liping Zhang, Robert H. Kline Iv, Terry A. Mcnearney, Michael P. Johnson, Karin Westlund High

Physiology Faculty Publications

BACKGROUND: Chronic Pancreatitis (CP) is a complex and multifactorial syndrome. Many contributing factors result in development of dysfunctional pain in a significant number of patients. Drugs developed to treat a variety of pain states fall short of providing effective analgesia for patients with chronic pancreatitis, often providing minimal to partial pain relief over time with significant side effects. Recently, availability of selective pharmacological tools has enabled great advances in our knowledge of the role of the cannabinoid receptors in pathophysiology. In particular, cannabinoid receptor 2 (CB2) has emerged as an attractive target for management of chronic pain, as demonstrated in …

Natural Selection On Thermal Performance In A Novel Thermal Environment, Michael L. Logan, Robert M. Cox, Ryan Calsbeek

Dartmouth Scholarship

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation …

Measurement Of Mullerian Inhibiting Substance Facilitates Management Of Boys With Microphallus And Cryptorchidism, Madhusmita Misra, David Maclaughlin, Patricia Donahoe, Mary Lee

Mary M. Lee

Mullerian inhibiting substance (MIS) is a gonadal hormone expressed in a sexually dimorphic pattern. In males, serum MIS reflects Sertoli cell function and provides an estimate of seminiferous tubular integrity. We examined the role of MIS determination in the evaluation of boys with microphallus (n = 62) and/or cryptorchidism (n = 156). MIS was normal in 69.2% of boys with isolated microphallus compared with 38.1% of boys with microphallus and coexisting cryptorchidism (P < 0.05). In the cryptorchid group, MIS was normal in 46.8%, low in 24.4%, and absent in 28.8%. Normal values for age were associated with testicular tissue, whereas …

Augmented Growth Hormone (Gh) Secretory Burst Frequency And Amplitude Mediate Enhanced Gh Secretion During A Two-Day Fast In Normal Men, Mark Hartman, Johannes Veldhuis, Michael Johnson, Mary Lee, K. Alberti, Eugene Samojlik, Michael Thorner

Mary M. Lee

Serum GH concentrations are increased in fasted or malnourished human subjects. We investigated the dynamic mechanisms underlying this phenomenon in nine normal men by analyzing serum GH concentrations measured in blood obtained at 5-min intervals over 24 h on a control (fed) day and on the second day of a fast with a multiple-parameter deconvolution method to simultaneously resolve endogenous GH secretory and clearance rates. Two days of fasting induced a 5-fold increase in the 24-h endogenous GH production rate [78 +/- 12 vs. 371 +/- 57 micrograms/Lv (Lv, liter of distribution volume) or 0.24 +/- 0.038 vs. 1.1 +/- …