Changes In Physiological State Research Articles

Photoperiodic effects on seasonal physiology, reproductive status and hypothalamic gene expression in young male F344 rats.

Seasonal or photoperiodically sensitive animals respond to altered day length with changes in physiology (growth, food intake and reproductive status) and behaviour to adapt to predictable yearly changes in the climate. Typically, different species of hamsters, voles and sheep are the most studied animal models of photoperiodism. Although laboratory rats are generally considered nonphotoperiodic, one rat strain, the inbred Fischer 344 (F344) rat, has been shown to be sensitive to the length of daylight exposure by changing its physiological phenotype and reproductive status according to the season. The present study aimed to better understand the nature of the photoperiodic response in the F344 rat. We examined the effects of five different photoperiods on the physiological and neuroendocrine responses. Young male F344 rats were held under light schedules ranging from 8 h of light/day to 16 h of light/day, and then body weight, including fat and lean mass, food intake, testes weights and hypothalamic gene expression were compared. We found that rats held under photoperiods of ≥ 12 h of light/day showed increased growth and food intake relative to rats held under photoperiods of ≤ 10 h of light/day. Magnetic resonance imaging analysis confirmed that these changes were mainly the result of a change in lean body mass. The same pattern was evident for reproductive status, with higher paired testes weight in photoperiods of ≥ 12 h of light/day. Accompanying the changes in physiological status were major changes in hypothalamic thyroid hormone (Dio2 and Dio3), retinoic acid (Crabp1 and Stra6) and Wnt/β-Catenin signalling genes (sFrp2 and Mfrp). Our data demonstrate that a photoperiod schedule of 12 h of light/day is interpreted as a stimulatory photoperiod by the neuroendocrine system of young male F344 rats.

Functional development of carbon dioxide detection in the maxillary palp of Anopheles gambiae.

ABSTRACTOlfactory information drives several behaviours critical for the survival and persistence of insect pests and vectors. Insect behaviour is variable, linked to their biological needs, and regulated by physiological dynamics. For mosquitoes, CO2 is an important cue that signifies the presence of a host, and which elicits activation and attraction. To investigate the genetic basis of olfactory modulation in mosquitoes, we assayed changes in CO2 detection from receptor gene expression through physiological function to behaviour, associated with the onset of host seeking in the malaria vector, Anopheles gambiae. The gene encoding a subunit of the CO2 receptor, AgGr22, was found to be significantly up-regulated in host-seeking females, consistent with a significant increase in sensitivity of CO2-responsive neurons (cpA) housed in capitate peg sensilla of the maxillary palp. In addition, the odorant receptor AgOr28, which is expressed in cpC neurons, was significantly up-regulated. In contrast, AgOr8, which is expressed in cpB neurons, was not affected by this change in physiological state, in agreement with results for the obligate co-receptor Orco. Moreover, the sensitivity of the cpB neuron to (R)-1-octen-3-ol, a well-known mammalian kairomone, did not change in response to the onset of host seeking. The concentration of CO2 flux influenced both the propensity of A. gambiae to take off into the wind and the speed with which this activation occurred. Female A. gambiae mosquitoes responded to CO2 whether mature for host seeking or not, but onset of host seeking enhanced sensitivity and speed of activation at relevant doses of CO2.

Circadian rhythms of ewes suckling singletons versus twins during the second week of lactation

Circadian rhythms are 24 hour cycles of physiology and behavior that evolved for adaptation to changes in environment and physiological state. We hypothesize circadian rhythms adjust to metabolic demands of lactation. Our objective was to determine if circadian rhythms of behavior, body temperature, cortisol and melatonin were different between ewes suckling twins and singletons after two weeks of lactation. Two groups of ewes (n = 5 ewes/group) suckling singleton or twin lambs were acclimated to sampling protocol for 5 d beginning 7 ± 1 d postpartum. After acclimation, behavior was measured (i.e. suckling, eating, drinking, lying down) every 10 min over 24 h. During the following 24 h period, milk, saliva, and rectal temperature were collected every 4 h. Salivary cortisol and melatonin levels were measured with ELISA. Singleton (4.1 ± 1.1 kg) and twin (5.2 ± 1.2 kg) lamb weight and ewe body condition score (BCS: 2.8 ± 0.2 and 2.7 ± 0.2, respectively) were not different (p > 0.05) at birth. At 9-12 d postpartum singleton (9.5 ± 2.6 kg) and twin (8.2 ± 1.5 kg) lamb weight and ewe BCS (2.9 ± 0.2 and 2.8 ± 0.2, respectively) were not different. However, total offspring weight per dam was greater in twin (15.5 ± 2.3 kg) than singleton (9.5 ± 2.6 kg; p < 0.05) group. Average daily gain for individual twins was roughly half of singleton, and net daily weight gain was not different, suggesting metabolic demand on ewes suckling twins was not significantly different from ewes suckling singletons. Lack of difference in suckling behavior score was consistent with lack of difference in metabolic demand between the groups of ewes. Salivary cortisol levels, melatonin levels, and rectal temperature measurements were not significantly different between groups. Circadian rhythms of standing, lying and eating behaviors were similar among groups. Ewes in the twin group ate more frequently during light phase suggesting that slightly higher metabolic demand of suckling twins may be met by increasing consumption alone in the first 2 weeks of lactation.

The Modified Early Warning Score (MEWS): an instant physiological prognostic indicator of poor outcome in acute pancreatitis.

The Modified Early Warning Score (MEWS) is a bedside scoring system that is non-invasive, simple and repeatable to reflect dynamic changes in physiological state. This study aims to assess accuracy of MEWS and determine an optimal MEWS value in predicting severity in acute pancreatitis (AP). A prospective database of consecutive admissions with AP to a single institution was analysed to determine value of MEWS in identifying severe acute pancreatitis (SAP) and predicting poor outcome. Receiver operator curves (ROC) were used to determine optimal accuracy. Sensitivity, specificity, negative predictive value (NPV), and positive predictive values (PPV) were calculated for the optimal MEWS values obtained. One-hundred and 42 patients with AP were included. The optimal highest MEWS per 24 hours period (hMEWS) and mean MEWS per 24 hour period (mMEWS) in predicting SAP as determined by ROC were 2.5 and 1.625 respectively; with hMEWS ≥3 and mMEWS &gt;1 utilised in this cohort as MEWS scores are whole numbers. On admission, sensitivity, specificity, NPV, PPV, and accuracy of hMEWS ≥3 was 95.5%, 90.8%, 99.0%, 65.6% and 92.0%; and for mMWES &gt;1 was 95.5%, 87.5%, 99.0%, 58.3% and 88.7%, both superior than the Imrie score: 31.5%, 92.1%, 88.9%, 40.0% and 83.5%. The accuracy of hMEWS ≥3 and mMEWS &gt;1 increased over the subsequent 72 hours (days 0-2) from 92 to 96%, and 89% to 94%, respectively. MEWS provides a novel, easy, instant, repeatable, reliable prognostic score that may be superior to existing scoring systems. A larger cohort is required to validate these findings.

Fatigue development in the finger flexor muscle differs between keyboard and mouse use.

The aim of the present study was to determine whether there were any physiological changes in the muscle as a result of intensive computer use. Using a repeated measures experimental design, eighteen subjects participated in four different 8-h conditions: a control (no exposure) condition and three exposure conditions comprised of 6 h of computer use (keyboard, mouse, and combined keyboard and mouse use) followed by 2 h of recovery. In each condition, using 2 Hz neuromuscular electrical stimulation, eight temporal measurements were collected to evaluate the fatigue state (twitch force, contraction time, and ½ relaxation time) of the right middle finger Flexor Digitorum Superficialis (FDS) muscle before, during, and after computer use. The results indicated that 6 h of keyboard, mouse, and combined mouse and keyboard use all caused temporal fatigue-related changes in physiological state of the FDS muscle. Keyboard use resulted in muscle potentiation, which was characterized by approximately 30% increase in twitch force (p < 0.0001) and 3% decrease (p = 0.04) in twitch durations. Mouse use resulted in a combined state of potentiation and fatigue, which was characterized by an increase in twitch forces (p = 0.002) but a prolonging (11 %) rather than a shortening of twitch durations (p < 0.0001). When comparing mouse and keyboard use, the more substantial change in the physiological state of the muscle with mouse use (potentiation and fatigue compared to just potentiation with keyboard use) provides some physiological evidence which may explain why mouse use has a greater association with computer-related injuries.

Gap Junction Proteins in the Blood-Brain Barrier Control Nutrient-Dependent Reactivation of Drosophila Neural Stem Cells

SummaryNeural stem cells in the adult brain exist primarily in a quiescent state but are reactivated in response to changing physiological conditions. How do stem cells sense and respond to metabolic changes? In the Drosophila CNS, quiescent neural stem cells are reactivated synchronously in response to a nutritional stimulus. Feeding triggers insulin production by blood-brain barrier glial cells, activating the insulin/insulin-like growth factor pathway in underlying neural stem cells and stimulating their growth and proliferation. Here we show that gap junctions in the blood-brain barrier glia mediate the influence of metabolic changes on stem cell behavior, enabling glia to respond to nutritional signals and reactivate quiescent stem cells. We propose that gap junctions in the blood-brain barrier are required to translate metabolic signals into synchronized calcium pulses and insulin secretion.

Effects of insemination and blood-feeding on locomotor activity of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) females under laboratory conditions

BackgroundDengue is an arbovirus disease transmitted by two Aedes mosquitoes: Ae. aegypti and Ae. albopictus. Virgin females of these two species generally show a bimodal and diurnal pattern of activity, with early morning and late afternoon peaks. Although some studies on the flight activity of virgin, inseminated and blood-fed Ae. aegypti females have been carried out under laboratory conditions, little is known about the effects of such physiological states on the locomotor activity of Ae. albopictus and Ae. aegypti females. The aim of this study was to analyze, under laboratory conditions, the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under LD 12:12, at 25°C.MethodsBoth Ae. albopictus and Ae. aegypti females were obtained from established laboratory colonies. Control groups were represented by virgin/unfed Ae. albopictus and Ae. aegypti females. Experiments were conducted under laboratory conditions, using an activity monitor that registers individual activity every thirty minutes.ResultsVirgin/unfed Ae. albopictus and Ae. aegypti females showed a diurnal and bimodal pattern of locomotor activity, with peaks at early morning and late afternoon. Insemination and blood-feeding significantly decreased the locomotor activity of Ae. aegypti females, but inseminated/blood-fed Ae. aegypti and Ae. albopictus females showed a similar significant decrease on the locomotor activity compared to virgin/unfed females.ConclusionsThis study is the first demonstration of the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under artificial conditions. Data suggest that Ae. albopictus and Ae. aegypti females respond in different ways to physiological status changes and such divergence between these two dengue vectors, associated with several ecological differences, could be related to the greater dengue vectorial capacity of Ae. aegypti in Americas in comparison to Ae. albopictus.

Altered effective connectivity of insula in nicotine addiction

To explore the changes of effective connectivity associated with insula in different nicotine addiction sessions so as to understand its role and function. A total of 20 smokers received the scans of resting-state functional magnetic resonance imaging in two sessions of different conditions: smoking abstinence followed by smoking satiety. Group ICA was initially adopted to obtain the independent component patterns. And paired t-test of ICA spatial patterns revealed such regions of interest as insula, parahippocampus, precuneus, dorsal anterior cingulate cortex, rostral anterior cingulate cortex, supplementary motor area and ventromedial/dorsolateral prefrontal cortex and effective connectivity from insula to other regions was examined subsequently with GCA. In smoking abstinence, insula showed increased effective connectivity with dorsolateral prefrontal cortex, ventromedial prefrontal cortex, dorsal anterior cingulate cortex, rostral anterior cingulate cortex, precuneus; while in smoking satiety, there was no significant changes for effective connectivity. Referring to graph theory analysis, the insula was a causal output source in smoking abstinence. Insula is a signal output node in smoking abstinence, with its interoceptive function monitoring the change of physiological state of body when in smoking abstinence, and then integrating each brain activity to produce subjective consciousness so as to facilitate addiction.

Microbial growth and carbon use efficiency in the rhizosphere and root-free soil.

Plant-microbial interactions alter C and N balance in the rhizosphere and affect the microbial carbon use efficiency (CUE)–the fundamental characteristic of microbial metabolism. Estimation of CUE in microbial hotspots with high dynamics of activity and changes of microbial physiological state from dormancy to activity is a challenge in soil microbiology. We analyzed respiratory activity, microbial DNA content and CUE by manipulation the C and nutrients availability in the soil under Beta vulgaris. All measurements were done in root-free and rhizosphere soil under steady-state conditions and during microbial growth induced by addition of glucose. Microorganisms in the rhizosphere and root-free soil differed in their CUE dynamics due to varying time delays between respiration burst and DNA increase. Constant CUE in an exponentially-growing microbial community in rhizosphere demonstrated the balanced growth. In contrast, the CUE in the root-free soil increased more than three times at the end of exponential growth and was 1.5 times higher than in the rhizosphere. Plants alter the dynamics of microbial CUE by balancing the catabolic and anabolic processes, which were decoupled in the root-free soil. The effects of N and C availability on CUE in rhizosphere and root-free soil are discussed.

Touch increases autonomic coupling between romantic partners.

Interpersonal touch is of paramount importance in human social bonding and close relationships, allowing a unique channel for affect communication. So far the effect of touch on human physiology has been studied at an individual level. The present study aims at extending the study of affective touch from isolated individuals to truly interacting dyads. We have designed an ecological paradigm where romantic partners interact only via touch and we manipulate their empathic states. Simultaneously, we collected their autonomic activity (skin conductance, pulse, respiration). Fourteen couples participated to the experiment. We found that interpersonal touch increased coupling of electrodermal activity between the interacting partners, regardless the intensity and valence of the emotion felt. In addition, physical touch induced strong and reliable changes in physiological states within individuals. These results support an instrumental role of interpersonal touch for affective support in close relationships. Furthermore, they suggest that touch alone allows the emergence of a somatovisceral resonance between interacting individuals, which in turn is likely to form the prerequisites for emotional contagion and empathy.

Relevance of biotic parameters in the assessment of the spatial distribution of gastrointestinal metal and protein levels during spawning period of European chub (Squalius cephalus L.)

The present field study, conducted during the spawning period (April/May) of European chub (Squalius cephalus L.) from the Sava River in Croatia, indicates that seasonal changes of fish physiological state might cause variability in gastrointestinal metal (Cd, Cu, Fe, Mn and Zn), total cytosolic protein and metallothionein (MT) levels. During the period of fish spawning and increased metabolic activity, a significant relationship with chub hepatosomatic index was evident for Fe and Mn in gastrointestinal tissue (r = 0.35 and 0.26, respectively) and in cytosolic fraction (r = 0.32 and 0.41, respectively) and for Zn and Fe in the gut content (r = 0.36 and 0.31, respectively). Total cytosolic protein and MT concentrations followed the same spatial distribution as Fe and Mn in all gastrointestinal fractions and as Zn in the sub-cellular fractions, with higher levels at upstream locations. Due to the role of essential metalsin metabolic processes and gonad development, increased feeding and spawningactivity in April/May resulted in highergastrointestinal essential metal (Fe, Mn and Zn) and MT concentrations, which probably follow an increase in Zn concentrations, known as the primary MT inducer. Therefore, biotic factors should be considered as important confounding factors in metal exposure assessment, while their influence on gastrointestinal metal and protein levels should be interpreted depending on the season studied.

FoxO3a-mediated activation of stress responsive genes during early torpor in a mammalian hibernator

The torpor-arousal cycle of mammalian hibernation is characterized by drastic changes in physiological state that are supported by reprogramming of metabolic functions. The entrance and arousal phases of the cycle function as transitional stages, where major changes in oxygen metabolism take place. Acute changes in oxygen delivery can lead to either ischemia-related injuries during torpor induction or reperfusion damage during arousal. This study examines the regulation of the forkhead box O3 (FoxO3) transcription factor, which functions to increase cellular cytoprotection in response to oxidative stress stimuli. Immunoblots show that total expression of FoxO3a was elevated during early torpor (ET) and late torpor by 3.6- and 4.5-fold, respectively, compared to euthermic control. However, enhanced phosphorylation of FoxO3a at Thr-32 was only evident during ET by 1.5-fold, accompanied by increased phosphorylation of c-Jun N-terminal kinases by 1.2-fold. During ET, increased nuclear inclusion of FoxO3a was evident along with its transcriptional co-activator β-catenin by 1.9- and 2.7-fold, respectively. As well, FoxO3a DNA binding was elevated by 1.8-fold during ET, along with increased expression of FoxO3a downstream genes catalase, p27, and cyclin G 2 , by 1.4-, 1.6-, and 1.3-fold, respectively. Overall, the results indicate activation of FoxO3a during ET, suggesting a role of FoxO3a in response to cellular stress during hibernation.

Self-reported physiological and psychological side-effects of an acute alcohol and energy drink dose

Objective: There have been repeated calls from health professionals and policy-makers to clarify the side-effects of the increasingly popular consumption trend of alcohol mixed with energy drinks (AmED). There is a dearth of research assessing the differential effects of AmED relative to alcohol by comparing self-reported psychological and physiological outcomes whilst under the influence of these substances. The aim of the present study was to examine the acute effects of a moderate alcohol and energy drink (ED) dose on self-reported psychological and physiological outcomes. Method: Using a single-blind, placebo-controlled, crossover design, 28 adults completed four sessions where they were administered: (i) 0.50g/kg alcohol, (ii) 3.57mL/kg ED, (iii) AmED, and (iv) placebo. Participants independently completed the Profile of Mood States and a Somatic Symptom Scale at baseline and at 30 and 125min after beverage administration. Results: Breath alcohol concentration peaked at .068% and .067% in the alcohol and AmED conditions, respectively. There were no interactive alcohol and ED effects on self-reported psychological outcomes. Treatment effects for physiological outcomes generally only related to alcohol or ED administration, with the exception of a moderate magnitude decrease in heart palpitation ratings following alcohol relative to AmED. Decreased muscular tension ratings were evident when the two constituents were consumed separately relative to placebo. Conclusions: The results provide evidence of few subjective changes in physiological and psychological state after consuming AmED relative to alcohol. The majority of treatment-based changes arose from the independent effects of alcohol or ED, rather than being modified by their interaction. However, research extending into higher dosage domains is required to increase outcome generalisability for consumers in the night-time economy.

Migration and stress during reproduction govern telomere dynamics in a seabird

Changes in telomere length are believed to reflect changes in physiological state and life expectancy in animals. However, much remains unknown about the determinants of telomere dynamics in wild populations, and specifically the influence of conditions during highly mobile life-history stages, for example migration. We tested whether telomere dynamics were associated with migratory behaviour and/or with stress during reproduction in free-living seabirds. We induced short-term stress during reproduction in chick-rearing, black-legged kittiwakes (Rissa tridactyla), tracked winter migration with geolocators and measured telomere length before and after winter migration. We found that time spent at wintering grounds correlated with reduced telomere loss, while stress during reproduction accelerated telomere shortening. Our results suggest that different life-history stages interact to influence telomere length, and that migratory patterns may be important determinants of variation in an individual's telomere dynamics.

Interaction between physiological and subjective states predicts the effect of a judging panel on the postures of cellists in performance.

This study investigated the effect of a panel of judges on the movements and postures of cellists in performance. Twenty four expert cellists played a short piece of music, to a metronome beat, in the presence and absence of the panel. Kinematic analyses showed that in the presence of the panel the temporal execution of left arm shifting movements became less variable and closer to the metronome beat. In contrast, the panel's presence had no reliable effect on their spatial accuracy. A detailed postural analysis indicated that left elbow angle during execution of a given high note was correlated with level of heart rate, though the nature of this correlation was systematically affected by the relevant participant's subjective state: if anxious, a higher heart rate correlated with a more flexed elbow, if not anxious then with a more extended elbow. Our results suggest a change in physiological state alone does not reliably predict a change in behavior in performing cellists, which instead depends on the interaction between physiological state and subjective experience of anxiety. This highlights a need to distinguish performance anxiety from physiological arousal, to which end we advocate currency for the specific term performance arousal to describe heightened physiological activity in a performer.

Chapter Nine - Developing MR Probes for Molecular Imaging

Molecular imaging plays an important role in the era of personalized medicine, especially with recent advances in magnetic resonance (MR) probes. While the first generation of these probes focused on maximizing contrast enhancement, a second generation of probes has been developed to improve the accumulation within specific tissues or pathologies, and the newest generation of agents is also designed to report on changes in physiological status and has been termed "smart" agents. This represents a paradigm switch from the previously commercialized gadolinium and iron oxide probes to probes with new capabilities, and leads to new challenges as scanner hardware needs to be adapted for detecting these probes. In this chapter, we highlight the unique features for all five different categories of MR probes, including the emerging chemical exchange saturation transfer, (19)F, and hyperpolarized probes, and describe the key physical properties and features motivating their design. As part of this comparison, the strengths and weaknesses of each category are discussed.

Stratification of gene coexpression patterns and GO function mining for a RNA-Seq data series.

RNA-Seq is emerging as an increasingly important tool in biological research, and it provides the most direct evidence of the relationship between the physiological state and molecular changes in cells. A large amount of RNA-Seq data across diverse experimental conditions have been generated and deposited in public databases. However, most developed approaches for coexpression analyses focus on the coexpression pattern mining of the transcriptome, thereby ignoring the magnitude of gene differences in one pattern. Furthermore, the functional relationships of genes in one pattern, and notably among patterns, were not always recognized. In this study, we developed an integrated strategy to identify differential coexpression patterns of genes and probed the functional mechanisms of the modules. Two real datasets were used to validate the method and allow comparisons with other methods. One of the datasets was selected to illustrate the flow of a typical analysis. In summary, we present an approach to robustly detect coexpression patterns in transcriptomes and to stratify patterns according to their relative differences. Furthermore, a global relationship between patterns and biological functions was constructed. In addition, a freely accessible web toolkit “coexpression pattern mining and GO functional analysis” (COGO) was developed.

Role of 3’-untranslated region translational control in cancer development, diagnostics and treatment

The messenger RNA 3'-untranslated region (3'UTR) plays an important role in regulation of gene expression on the posttranscriptional level. The 3'UTR controls gene expression via orchestrated interaction between the structural components of mRNAs (cis-element) and the specific trans-acting factors (RNA binding proteins and non-coding RNAs). The crosstalk of these factors is based on the binding sequences and/or direct protein-protein interaction, or just functional interaction. Much new evidence that has accumulated supports the idea that several RNA binding factors can bind to common mRNA targets: to the non-overlapping binding sites or to common sites in a competitive fashion. Various factors capable of binding to the same RNA can cooperate or be antagonistic in their actions. The outcome of the collective function of all factors bound to the same mRNA 3'UTR depends on many circumstances, such as their expression levels, affinity to the binding sites, and localization in the cell, which can be controlled by various physiological conditions. Moreover, the functional and/or physical interactions of the factors binding to 3'UTR can change the character of their actions. These interactions vary during the cell cycle and in response to changing physiological conditions. Abnormal functioning of the factors can lead to disease. In this review we will discuss how alterations of these factors or their interaction can affect cancer development and promote or enhance the malignant phenotype of cancer cells. Understanding these alterations and their impact on 3'UTR-directed posttranscriptional gene regulation will uncover promising new targets for therapeutic intervention and diagnostics. We will also discuss emerging new tools in cancer diagnostics and therapy based on 3'UTR binding factors and approaches to improve them.

Insulin/IGF-Regulated Size Scaling of Neuroendocrine Cells Expressing the bHLH Transcription Factor Dimmed in Drosophila

Neurons and other cells display a large variation in size in an organism. Thus, a fundamental question is how growth of individual cells and their organelles is regulated. Is size scaling of individual neurons regulated post-mitotically, independent of growth of the entire CNS? Although the role of insulin/IGF-signaling (IIS) in growth of tissues and whole organisms is well established, it is not known whether it regulates the size of individual neurons. We therefore studied the role of IIS in the size scaling of neurons in the Drosophila CNS. By targeted genetic manipulations of insulin receptor (dInR) expression in a variety of neuron types we demonstrate that the cell size is affected only in neuroendocrine cells specified by the bHLH transcription factor DIMMED (DIMM). Several populations of DIMM-positive neurons tested displayed enlarged cell bodies after overexpression of the dInR, as well as PI3 kinase and Akt1 (protein kinase B), whereas DIMM-negative neurons did not respond to dInR manipulations. Knockdown of these components produce the opposite phenotype. Increased growth can also be induced by targeted overexpression of nutrient-dependent TOR (target of rapamycin) signaling components, such as Rheb (small GTPase), TOR and S6K (S6 kinase). After Dimm-knockdown in neuroendocrine cells manipulations of dInR expression have significantly less effects on cell size. We also show that dInR expression in neuroendocrine cells can be altered by up or down-regulation of Dimm. This novel dInR-regulated size scaling is seen during postembryonic development, continues in the aging adult and is diet dependent. The increase in cell size includes cell body, axon terminations, nucleus and Golgi apparatus. We suggest that the dInR-mediated scaling of neuroendocrine cells is part of a plasticity that adapts the secretory capacity to changing physiological conditions and nutrient-dependent organismal growth.

A Psychophysiology of Developmental Disabilities: A Personal and Historical Perspective

In the early 1970s, as a curious young assistant professor in the Department of Psychology at the University of Illinois at Urbana–Champaign, my colleagues asked me to apply heart rate monitoring to study the intellectually impaired. Although many of my colleagues were dedicated to the study of developmental disabilities, this was a new area for me. The University of Illinois had a physical center and an administrative structure to expand the behavioral sciences into the study of typically and atypically developing children, and the Children’s Research Center was the epicenter of this research interest. The Center was headed by Bob Sprague and included several researchers—Steve Asher, Ann Brown, Joe Campione, Mark Gold, and Keith and Marcia Scott—who conducted research on mentally challenged children. The research conducted at the Center was well funded and was a high priority for both the State of Illinois and the National Institutes of Health. In retrospect, this was a special time and special place for the study of normal and atypical development. I recall one meeting in which approximately 35 faculty members across several departments and colleges on the University of Illinois at Urbana–Champaign campus self-identified as developmental psychologists. It was an optimistic time, and there were expectations that physiological monitoring would provide a portal to better understand individuals with limited language skills and cognitive resources. In the 1970s, the State of Illinois was committed to improving the quality of children with developmental disabilities. There were statefunded centers for treatment and research and state-funded research grants. For example, in Chicago, the state funded an intramural research program in a facility on the University of Illinois Medical School campus known as the Illinois State Pediatric Institute. This facility was located adjacent to another state-funded research program known as the Illinois State Psychiatric Institute. These large buildings housed basic and clinical researchers focused on understanding and improving the lives of individuals with developmental disabilities and mental health disorders. During the mid-1970s, in this background of interest and enthusiasm for research to study atypical development, I received a grant from the State of Illinois, Department of Mental Health and Developmental Disabilities to study heart rate patterns in ‘‘retarded and nonretarded’’ adolescents. To conduct this research, I borrowed from my colleague, Bob Sprague, a van that had been modified into a two-room research laboratory. With a graduate student, Mary Humphrey, and the help of a couple of talented undergraduates, we drove the van to local schools to collect the data. To do a simple study, we packed about 200 pounds of equipment into the van, including a Beckman Dynograph, an FM tape recorder, a 6-foot equipment rack containing relays programmed to display the stimulus via a slide projector and to record the responses through button presses, and a TV monitor and camera to reduce fear and uncertainty for the participants by enabling them to observe each other participating. The study resulted in a publication in the American Journal of Mental Deficiency (Porges & Humphrey, 1977), which was the former name of the American Journal on Intellectual and Developmental Disabilities. What has changed in the decades since my paper with Mary and this issue of the Journal on Intellectual and Developmental Disabilities? From my perspective, there have been three major interrelated changes. First, in 1977, it would have been virtually impossible to find sufficient intellectual material on heart rate monitoring in special populations to fill an issue of any journal. In the mid-1970s, only a few researchers studied autonomic function in special populations. Most notable was Rathe Karrer. Rathe was a psychoAMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES