Home About us Contact
|
Home About us Contact | ||
|
|
||
Months Old (month + old)
Terms modified by Months Old Selected AbstractsThe effects of elevated CO2 on root respiration rates of two Mojave Desert shrubsGLOBAL CHANGE BIOLOGY, Issue 5 2010NAOMI M. CLARK Abstract Although desert ecosystems are predicted to be the most responsive to elevated CO2, low nutrient availability may limit increases in productivity and cause plants in deserts to allocate more resources to root biomass or activity for increased nutrient acquisition. We measured root respiration of two Mojave Desert shrubs, Ambrosia dumosa and Larrea tridentata, grown under ambient (,375 ppm) and elevated (,517 ppm) CO2 concentrations at the Nevada Desert FACE Facility (NDFF) over five growing seasons. In addition, we grew L. tridentata seedlings in a greenhouse with similar CO2 treatments to determine responses of primary and lateral roots to an increase in CO2. In both field and greenhouse studies, root respiration was not significantly affected by elevated CO2. However, respiration of A. dumosa roots <1 month old was significantly greater than respiration of A. dumosa roots between 1 and 4 months old. For both shrub species, respiration rates of very fine (<1.0 mm diameter) roots were significantly greater than those of fine (1,2 mm diameter) roots, and root respiration decreased as soil water decreased. Because specific root length was not significantly affected by CO2 and because field minirhizotron measurements of root production were not significantly different, we infer that root growth at the NDFF has not increased with elevated CO2. Furthermore, other studies at the NDFF have shown increased nutrient availability under elevated CO2, which reduces the need for roots to increase scavenging for nutrients. Thus, we conclude that A. dumosa and L. tridentata root systems have not increased in size or activity, and increased shoot production observed under elevated CO2 for these species does not appear to be constrained by the plant's root growth or activity. [source] CHEMICAL PROPERTIES of PROCESSED RAS CHEESE SPREADS AS AFFECTED BY EMULSIFYING SALT MIXTURES,JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2000LAILA B. ABDEL-HAMID Processed cheese spreads were produced using Ras cheese and various emulsifying salt mixtures. Acidified Ras cheese (2 month old) was used as the cheese base with salt mixtures (1) Na-pyrophosphate + Na-polyphosphate, (2) Na-pyrophosphate + Na-polyphosphate + Na-tripolyphosphate, and (3) Na-pyrophosphate + Na-polyphosphate + Na-orthophosphate + Na-tripolyphosphate. For comparison, cheese spreads were also made with commercial emulsifying salts JOHA S10, S9 special, and NO. Total and soluble nitrogen (SN), peptization, ash, mineral, pH value, and potentiometric acid-base titration for the processed cheese were studied. Ash, sodium and potassium contents showed a significant difference among the treatments. the pH values tended to decrease with increasing polyphosphate ratio in the salt mixture and with prolonging the storage period. the SN increased with increasing the pyrophosphate percent in the salt mixture and with higher pH value. the buffering capacity of cheese made of salt mixtures difsered from those made of the commercial mixtures, and it was correlated to the individual salts used in the mixture. The mixtures of (1) 70+30%, (2) 60+30+10% and (3) 50+20+20+10% can be recommended for producing the spreadable processed Ras cheese with acceptable chemical properties. [source] A simple method to reduce the inspiratory oxygen fraction for high pulmonary blood flow patients in an operating roomPEDIATRIC ANESTHESIA, Issue 12 2007AYAKO ASAKURA MD Summary Background:, Low inspired oxygen acutely increases pulmonary vascular resistance and decreases pulmonary-systemic blood flow ratio. We present a simple method to lower inspired oxygen fraction (FIO2 < 0.21) without supplemental nitrogen, during mechanical ventilation by an anesthesia machine. Methods:, After institutional approval, seven healthy adult volunteers and three infants (0,12 month old) scheduled for congenital heart surgery were enrolled in this study. All the infants were diagnosed with congestive heart failure because of high pulmonary blood flow and were thought to benefit from low FIO2. The volunteers performed spontaneous ventilation (fresh air flow rate = 10 l·min,1, tidal volume = 600 ml, frequency = 10 br·min,1). The infants were mechanically ventilated with air (fresh air flow rate = 6 l·min,1, tidal volume = 10 ml·kg,1, 15 < frequency < 30 br·min,1 to adjust PaCO2 between 5.8 kPa and 6.5 kPa (45,50 mmHg), after induction of general anesthesia and tracheal intubation. The fresh gas flow rates were determined by the following formula. Fresh gas flow rate = (FIO2 , FEO2) EVE/(0.21 + FIO2 , FEO2 , target FIO2). We recorded FIO2 every 5 min for 30 min. When arterial oxygen saturation decreased >15%, fresh gas flow rates were increased to adjust FIO2 to 0.21. Results:, In all of the seven volunteers and three infants target FIO2 was achieved in <10 min. FIO2 was kept at 0.18 ± 0.01 (SD) by calculated fresh air flow rates. In one infant, SpO2 decreased >15% 20 min after lowering FIO2, we had to discontinue this study, and increase fresh gas flow to ventilate the infant with FIO2 0.21. In the other two infants, FIO2 was maintained throughout the study. Conclusions:, This simple and convenient method to decrease FIO2, has a utility in clinical situations, in which pulmonary vascular resistance is to be increased to improve systemic oxygen delivery in patients with high pulmonary blood flow during cardiac surgery. [source] Correction of enzyme levels with allogeneic hematopoeitic progenitor cell transplantation in Niemann-Pick type BPEDIATRIC BLOOD & CANCER, Issue 7 2007Jennifer Schneiderman MD Abstract Niemann-Pick type B (NP) is an autosomal recessive lysosomal storage disorder with variable phenotypes for which few patients have undergone hematopoietic progenitor cell (HPC) transplantation. We present an 18-month old with NP type B who underwent two allogeneic HPC transplants from her HLA-identical sister. Sphingomyelinase in the peripheral leucocytes and skin fibroblasts was absent at diagnosis. Engraftment failed following initial transplant; therefore a second with the same donor was performed. Engraftment since has been durable; all subsequent sphingomyelinase levels have been normal. Our experience indicates that HPC transplantation for patients with NP type B is feasible and beneficial. Pediatr Blood Cancer 2007;49:987,989. © 2007 Wiley-Liss, Inc. [source] Gene transfer of vascular endothelial growth factor reduces bleomycin-induced pulmonary hypertension in immature rabbitsPEDIATRICS INTERNATIONAL, Issue 3 2005Fangqi Gong AbstractBackground:,The purpose of the present paper was to investigate the effect of gene transfer of vascular endothelial growth factor (VEGF) on bleomycin (BLM)-induced pulmonary hypertension in immature rabbits. Methods:,Immature rabbits (1 month old) were divided into control group (intratracheal injection of normal saline), BLM group (intratracheal injection of BLM), liposome group (intratracheal injection of BLM and liposomes) and the trans-gene group (intratracheal injection of BLM and DNA,liposome complex). The pulmonary arterial pressure (PAP) were measured by microcatheter, the pathological changes and the expression of VEGFmRNA and endothelial nitric oxide synthase (eNOS) mRNA of endothelial cells in pulmonary arteries were evaluated by hematoxylin,eosin (HE) and in situ hybridization. Results:,The PAP of the BLM and liposome groups were higher than the PAP of the control and trans-gene groups. The thickness of wall increased and the cavity became narrow, and thickness index and area index increased in mid- and small-sized pulmonary arteries of the BLM and liposome groups. VEGF trans-gene was able to reduce those changes; the level of VEGFmRNA and eNOSmRNA expression in pulmonary arterial endothelial cells decreased in the BLM and liposome groups. The level of VEGFmRNA expression in the trans-gene group was higher than that in the BLM and liposome groups, but lower than that in the control group. Conclusion:,The PAP was elevated, the thickness of wall increased and the cavity became narrow in mid- and small-sized pulmonary arteries, and the level of VEGFmRNA and eNOSmRNA expression in pulmonary arterial endothelial cells decreased in immature rabbits after 2 weeks of intratracheal injection of 4 units/kg BLM. VEGF trans-gene could reduce those changes. [source] Electrophysiologic Effects of Placing Cochlear Implant Electrodes in a Perimodiolar Position in Young Children,THE LARYNGOSCOPE, Issue 1 2004Phillip A. Wackym MD Abstract Objective The purpose of this study was to intraoperatively record the electrically evoked auditory brainstem response (EABR) before and after placement of the electrode positioning system (EPS) (CII Bionic Ear with HiFocus I cochlear implant electrode array) as well as before and after stylet removal (Nucleus Contour cochlear implant electrode array). It was hypothesized that physiologic changes would occur after perimodiolar positioning of the electrode array and these changes would be evident from the EABR recordings. Study Design Consecutive young (11,36 month old) pediatric cochlear implant recipients (n = 17) had intraoperative EABRs recorded from three intracochlear electrodes that represented apical, medial, and basal locations. Wave V amplitudes and thresholds were studied relative to electrode location and pre- versus postperimodiolar positioning. These evoked potential measures were analyzed for statistical significance. Setting Tertiary referral children's hospital/medical college. Results Wave V thresholds of the EABR were lower, and amplitudes were larger after perimodiolar positioning, although the changes were dependent on electrode location and implant design. Statistically significant decreases in EABR wave V threshold and increases in suprathreshold wave V amplitude were found for the basal electrode for the CII Bionic Ear HiFocus I and for the apical electrode for the Nucleus Contour. Conclusions Placement of either the CII Bionic Ear HiFocus I or Nucleus Contour cochlear implant electrode array in the perimodiolar position in young children resulted in less electrical current necessary to stimulate the auditory system. Changes in electrophysiologic thresholds and amplitudes, measured with EABR, indicate that the electrode array is placed closer to the modiolus with both electrode designs. [source] Self,other awareness and peer relationships in toddlers: gender comparisonsINFANT AND CHILD DEVELOPMENT, Issue 5 2010Laura E. Levine Abstract Toddlers' growing self,other awareness has been linked with their ability to interact with peers, but there is reason to think that self,other awareness may relate to different aspects of peer relationships for boys and girls. We hypothesized that boys would express self,other awareness by separating self from other through claiming toys, while girls would express self,other awareness by creating similarities between self and other through use of the duplicate of a partner's toy. For 52 22,26,month olds, self,other awareness was assessed through four tasks: mirror self recognition, perceptual role taking, pronoun recognition and pronoun use. Each child subsequently interacted with a same-sex peer for 30,min. Girls high in self,other awareness, and their partners were more likely to engage in duplicate toy use than girls low in self,other awareness. No differences in toy claiming were found. Future longitudinal research would clarify how the onset of self,other awareness relates to developments in peer interaction for girls and boys. Copyright © 2010 John Wiley & Sons, Ltd. [source] Sequence and priming in 15 month-olds' reactions to brief arm restraint: evidence for a hierarchy of anger responsesAGGRESSIVE BEHAVIOR, Issue 6 2007Michael Potegal Abstract Brief, gentle arm restraint is widely used in experimental studies of children's anger, but the pattern of responses generated by such restraint has been incompletely described. We now describe a hierarchy of responses within trials as well as an escalation across trials that have both methodological and theoretical significance. Mothers of 87 15-month olds prevented them from playing with a toy by restraining their arms on two consecutive 30,sec trials. Physical struggling was the first and most frequent response; children who struggled were significantly more likely to vocalize, and those who vocalized were significantly more likely to show facial expressions of anger. The children's responses became more probable, rapid, and intense during Trial 2 restraint. Overall, the hierarchy was orderly enough to meet criteria for Guttman scalability. The particular sequence observed suggests situational, as opposed to bio-energetic, ordering of responses. Methodologically, the two trial paradigm is a simple, ecologically valid model for studying anger escalation that parallels the "attack priming" of aggression in other species. The magnitude and persistence of anger priming may provide novel measures of anger regulation. Theoretically, the existence of an orderly response hierarchy is consistent with previous observations suggesting that, within a situational context, the sequential appearance of specific behaviors may indicate progressive increases in anger intensity. Aggr. Behav. 33:508,518, 2007. © 2007 Wiley-Liss, Inc. [source] Odontoma-like malformation in a permanent maxillary central incisor subsequent to trauma to the incisor predecessorDENTAL TRAUMATOLOGY, Issue 5 2005Paulo Nelson-Filho Abstract,,, This report describes a case of a patient (1 year and 8 months old) with traumatic avulsion of the maxillary right primary central incisor and morphological changes in the germ of the permanent successor. One year after the trauma, an odontoma-like malformation developed. This malformation was removed 6 years after trauma and orthodontic treatment was started. Clinical follow-up and periodic radiographs are necessary after traumatic avulsion of primary teeth to monitor possible sequelae in the permanent successor. An odontoma-like malformation requires a multidisciplinary approach. [source] The sleep of co-sleeping infants when they are not co-sleeping: Evidence that co-sleeping is stressfulDEVELOPMENTAL PSYCHOBIOLOGY, Issue 1 2002Melissa Hunsley Abstract Co-sleeping proponents consider the practice to be "natural" and a potential protection against sudden infant death syndrome (SIDS); others consider the practice of an infant sleeping in the parents' bed for prolonged periods at night to place an infant at risk for harm or death. For this study, co-sleeping was investigated from a different perspective, that is, as a significant early experience to investigate as it may have implications for the infant's development. The sleep of 101 normal, full-term infants was recorded nonintrusively in the home for 24 hr periods when they were 5 weeks and 6 months old. Infants were assigned to three groups: short-term co-sleepers, long-term co-sleepers, and non-co-sleepers. Their sleep states and wakefulness were compared at the two ages and over age. At 5 weeks and 6 months, the long-term co-sleeping infants differed significantly from the non-co-sleepers on a number of measures: At 5 weeks, they showed more quiet sleep and longer bouts of quiet sleep; and at 6 months, they also showed less active sleep, fewer arousals in active sleep, and less wakefulness. Each of these differences indicates a markedly lower arousal level in the long-term co-sleeping infants. This sleep pattern has been repeatedly found to be an indicator of stress. We infer that a major source of stress for these infants is the experience of sleep disturbance documented for infants when they were co-sleeping. Based on extensive evidence for long-term effects of early stress, we conclude that co-sleeping should have significant implications for infants' neurobehavioral development. © 2002 John Wiley & Sons, Inc. Dev Psychobiol 40: 14,22, 2002 [source] Development of using experimenter-given cues in infant chimpanzees: longitudinal changes in behavior and cognitive developmentDEVELOPMENTAL SCIENCE, Issue 1 2008Sanae Okamoto-Barth The use of gaze shifts as social cues has various evolutionary advantages. To investigate the developmental processes of this ability, we conducted an object-choice task by using longitudinal methods with infant chimpanzees tested from 8 months old until 3 years old. The experimenter used one of six gestures towards a cup concealing food; tapping, touching, whole-hand pointing, gazing plus close-pointing, distant-pointing, close-gazing, and distant-gazing. Unlike any other previous study, we analyzed the behavioral changes that occurred before and after choosing the cup. We assumed that pre-choice behavior indicates the development of an attentional and spatial connection between a pointing cue and an object (e.g. Woodward, 2005); and post-choice behavior indicates the emergence of object permanence (e.g. Piaget, 1954). Our study demonstrated that infant chimpanzees begin to use experimenter-given cues with age (after 11 months of age). Moreover, the results from the behavioral analysis showed that the infants gradually developed the spatial link between the pointing as an object-directed action and the object. Moreover, when they were 11 months old, the infants began to inspect the inside of the cup, suggesting the onset of object permanence. Overall, our results imply that the ability to use the cues is developing and mutually related with other cognitive developments. The present study also suggests what the standard object-choice task actually measures by breaking the task down into the developmental trajectories of its component parts, and describes for the first time the social-physical cognitive development during the task with a longitudinal method. [source] Amplitude and Velocity of Mitral Annulus Motion in RabbitsECHOCARDIOGRAPHY, Issue 4 2004Li-ming Gan M.D., Ph.D. Objective: During recent years, the amplitude and the maximal systolic velocity of the mitral annulus motion (MAM) have been established as indices of the left ventricular systolic function and the maximal diastolic velocity of the annulus motion has been suggested as an index of diastolic function. The main aims of the present study were to investigate the feasibility of these techniques in rabbits and to investigate age-related changes concerning these variables. Methods: Twenty-one New Zealand white rabbits were investigated by echocardiographic M-mode and pulsed tissue Doppler. One subgroup (I) included 11 still-growing, 3.0 ± 0.2 month-old, animals and another group (II) included 10 young grown up rabbits, 12.1 ± 1.5 months old. Results: The amplitude (4.8 ± 0.6 and 3.5 ± 0.3 mm, respectively) and maximal systolic (98 ± 14 and 66 ± 7 mm/s, respectively) and diastolic (111 ± 21 and 80 ± 12 mm/s, respectively) velocities of the MAM were significantly (P < 0.001) higher in group I than in group II, despite a bigger heart in the animals in the latter group. A coefficient of variation of <5% was found for both inter- and intraobserver variability for both amplitude and velocities. Conclusions: The amplitude and velocities of MAM are easily recorded in rabbits with excellent reproducibility and the changes with age seem to be very similar to those in humans. These noninvasive M-mode and tissue Doppler methods are therefore suitable for the investigation of left ventricular function in experimental studies in rabbits. (ECHOCARDIOGRAPHY, Volume 21, May 2004) [source] Morphological alterations in the amygdala and hippocampus of mice during ageingEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2002Oliver Von Bohlen und Halbach Abstract Declines in memory function and behavioural dysfunction accompany normal ageing in mammals. However, the cellular and morphological basis of this decline remains largely unknown. It was assumed for a long time that cell losses in the hippocampus accompany ageing. However, recent stereological studies have questioned this finding. In addition, the effect of ageing is largely unknown in another key structure of the memory system, the amygdala. In the present study, we have estimated neuronal density and total neuronal numbers as well as density of fragments of degenerated axons in different hippocampal subfields and amygdaloid nuclei. Comparisons were made among aged (21,26 months old) mice and normal adult littermates (8 months old). No significant volume loss occurs in the hippocampus of aged mice. Small but insignificant reductions in total neuronal numbers were found in the hippocampus and in the amygdaloid nuclei. In contrast to the mild effects of ageing upon neuronal numbers, fragments of degenerated axons were increased in both hippocampus and amygdala of aged mice. These data suggest that ageing does not induce prominent cell loss in the hippocampus or amygdala, but leads to degeneration of axons that innervate these forebrain structures. Thus, mechanisms underlying age-related dysfunction depend on parameters other than neuronal numbers, at least in the hippocampal formation and the amygdala. [source] Exercise training attenuates ageing-induced BKCa channel downregulation in rat coronary arteriesEXPERIMENTAL PHYSIOLOGY, Issue 6 2010Sulayma Albarwani Physical inactivity and ageing are widely recognized as risk factors for development of coronary artery disease. One of the characteristic changes that occurs in aged coronary artery is downregulation of their large-conductance voltage- and calcium-activated K+ (BKCa) channels. In this study, we investigated the effects of moderate exercise training (ET) on the activity of BKCa channels in coronary arteries of aged rats. Old Fischer 344 rats (23,26 months old) were randomly assigned to sedentary (O-SED, n= 24) or exercise-trained groups (O-ET, n= 28). The O-ET rats underwent a progressive treadmill exercise-training programme for 60 min day,1, 5 days week,1 for 12 weeks. Young animals were used for comparison. Coronary arteries were mounted on a wire myograph, and contractions in response to 1, 10, 30, 50 and 100 nmol l,1 iberiotoxin were compared. Iberiotoxin (100 nmol l,1) contracted coronary arteries of young, O-SED and O-ET rats by 115 ± 14, 36 ± 5.6 and 61 ± 5% of 5-hydroxytryptamine-induced contractions, respectively. Patch-clamp studies revealed a larger magnitude of BKCa current in young (104 ± 15.6 pA pF,1) compared with O-ET (44 ± 9 pA pF,1) and least in O-SED coronary smooth muscle cells (8.6 ± 2 pA pF,1). Western immunoblotting was performed to study expression levels of BKCa channel proteins. The , and ,1 subunits of the BKCa channel were reduced by 40 ± 3.5 and 30 ± 2.6%, respectively, in coronary arteries of old compared with young rats, and ET attenuated this reduction in expression level to 28 ± 2 and 12 ± 4%, respectively. Our results showed that ageing was associated with a reduction in BKCa channels, and ET partly reversed this reduction. We conclude that low-intensity ET may be beneficial in restoring age-related decline in coronary vasodilatory properties mediated by BKCa channels. [source] Chronic Hypoxia Delays Myocardial Lactate Dehydrogenase Maturation in Young RatsEXPERIMENTAL PHYSIOLOGY, Issue 3 2003Z. Daneshrad The effect of exposure to hypobaric hypoxia for 4 weeks (oxygen pressure = 106 hPa), equivalent to 5500 m in altitude) on myocardial total lactate dehydrogenase (tLDH) activity and isoform (H and M) composition was comparatively studied in growing (4.5 weeks old) and in adult (4.5 months old) male rats. The consequences of the hypoxia-induced anorexia were checked in growing rats using a pair-fed group. Exposure to hypoxia induced a significant decrease in the H/tLDH ratio in the left (LV) and right ventricle (RV) of growing and adult rats. In adult rats this alteration was mainly a consequence of the significant increase in the specific activity of the M isomer, which resulted in an increase in the overall LDH activity. In contrast, in the LV of young rats exposed to hypoxia, the specific activity of the M isomer was similar to that of normoxic animals while the H isomer activity was significantly lower than in normoxic rats, and the overall LDH activity remained unchanged. These effects were specifically due to hypoxia per se since no significant alterations were observed in pair-fed animals. In the hypertrophied RV, the alteration of H and M isomers following hypoxia was similar to that observed in adults (i.e. no change in H and an increase in M isoform). We conclude that the well-known hypoxia-induced decrease in the H/tLDH ratio is governed by different age-dependent mechanisms. In adult rats, hypoxia may induce in both ventricles a stimulating effect on M isomer expression. In the LV of growing rats this stress could inhibit the H isomer maturation without any effect on the M isomer. In the RV of growing rats this effect could have been counteracted by the growth effect of the hypertrophying process. [source] The effects of elevated CO2 on root respiration rates of two Mojave Desert shrubsGLOBAL CHANGE BIOLOGY, Issue 5 2010NAOMI M. CLARK Abstract Although desert ecosystems are predicted to be the most responsive to elevated CO2, low nutrient availability may limit increases in productivity and cause plants in deserts to allocate more resources to root biomass or activity for increased nutrient acquisition. We measured root respiration of two Mojave Desert shrubs, Ambrosia dumosa and Larrea tridentata, grown under ambient (,375 ppm) and elevated (,517 ppm) CO2 concentrations at the Nevada Desert FACE Facility (NDFF) over five growing seasons. In addition, we grew L. tridentata seedlings in a greenhouse with similar CO2 treatments to determine responses of primary and lateral roots to an increase in CO2. In both field and greenhouse studies, root respiration was not significantly affected by elevated CO2. However, respiration of A. dumosa roots <1 month old was significantly greater than respiration of A. dumosa roots between 1 and 4 months old. For both shrub species, respiration rates of very fine (<1.0 mm diameter) roots were significantly greater than those of fine (1,2 mm diameter) roots, and root respiration decreased as soil water decreased. Because specific root length was not significantly affected by CO2 and because field minirhizotron measurements of root production were not significantly different, we infer that root growth at the NDFF has not increased with elevated CO2. Furthermore, other studies at the NDFF have shown increased nutrient availability under elevated CO2, which reduces the need for roots to increase scavenging for nutrients. Thus, we conclude that A. dumosa and L. tridentata root systems have not increased in size or activity, and increased shoot production observed under elevated CO2 for these species does not appear to be constrained by the plant's root growth or activity. [source] Age-dependent enhancement of inhibitory synaptic transmission in CA1 pyramidal neurons via GluR5 kainate receptorsHIPPOCAMPUS, Issue 8 2009Changqing Xu Abstract Changes in hippocampal synaptic networks during aging may contribute to age-dependent compromise of cognitive functions such as learning and memory. Previous studies have demonstrated that GABAergic synaptic transmission exhibits age-dependent changes. To better understand such age-dependent changes of GABAergic synaptic inhibition, we performed whole-cell recordings from pyramidal cells in the CA1 area of acute hippocampal slices on aged (24,26 months old) and young (2,4 months old) Brown-Norway rats. We found that the frequency and amplitude of spontaneous inhibitory postsynaptic current (IPSCs) were significantly increased in aged rats, but the frequency and amplitude of mIPSCs were decreased. Furthermore, the regulation of GABAergic synaptic transmission by GluR5 containing kainate receptors was enhanced in aged rats, which was revealed by using LY382884 (a GluR5 kainate receptor antagonist) and ATPA (a GluR5 kainate receptor agonist). Moreover, we demonstrated that vesicular glutamate transporters are involved in the kainate receptor dependent regulation of sIPSCs. Taken together, these results suggest that GABAergic synaptic transmission is potentiated in aged rats, and GluR5 containing kainate receptors regulate the inhibitory synaptic transmission through endogenous glutamate. These alterations of GABAergic input with aging could contribute to age-dependent cognitive decline. © 2009 Wiley-Liss, Inc. [source] Immunohistochemical expression patterns of AP2, and AP2, in the developing fetal human breastHISTOPATHOLOGY, Issue 6 2007N Friedrichs Aims:, AP2, (TFAP2A) and AP2, (TFAP2G) transcription factors have been implicated in the control of proliferation, differentiation and apoptosis of normal breast epithelium and in breast cancer. The aim of this study was to provide a comprehensive analysis of the expression patterns of TFAP2A and TFAP2G in the developing fetal breast anlage with other relevant markers. Methods and results:, Sixty fetal and one infant human breast specimens from 14 weeks of gestational age to 5 months old were examined. The primary breast outgrowth/nipple showed TFAP2A expression by the basal cells (week 14), followed later by cytokeratin (CK) 5 co-expression (week 17). Sprouting of the secondary outgrowths was characterized by HER-2+ invading cells. Preliminary ductal buds were lined by TFAP2G/HER-1-expressing myoepithelial precursors (week 19). Maturation of TFAP2A/CK18+ epithelia and TFAP2G/smooth muscle actin-positive myoepithelia proceeded in a distal-to-proximal manner beginning in the terminal end buds (week 22). CK5+ progenitor cells and CK5/TFAP2A or CK5/TFAP2G co-expressing intermediary glandular or myoepithelial cells were found in the terminal end buds of neonatal fetal breast tissue. Conclusions:, AP2 transcription factors may play decisive pacemaker roles in initiating and coordinating budding and branching processes during formation of the fetal breast anlage, possibly via modulation of an epidermal growth factor receptor. [source] Transcription of major histocompatibility complex class I (Kb) and transporter associated with antigen processing 1 and 2 genes is up-regulated with ageIMMUNOLOGY, Issue 3 2004Alain G. Assounga Summary The transporter associated with antigen processing 1 and 2 (TAP1 and TAP2) genes belong to the ATP-binding cassette family of transporter genes. They provide peptides necessary for the assembly of major histocompatibility complex (MHC) class I molecules by transporting these peptides into the endoplasmic reticulum. As MHC class I protein expression increases with age, we have explored the effect of age on the transcription of MHC class I genes (Kb) and TAP1 and TAP2 genes in C57BL/6 mice. Blood and spleen lymphocytes were isolated from mice aged from 3 months to over 24 months. RNA was extracted and mRNA for Kb, TAP1, TAP2 was quantified using slot-blot hybridization followed by densitometry. There was a parallel age-related increase (1·5-fold) in blood lymphocyte mRNA of these genes from 3 months to 21 months. In mice over 24 months old there was a decrease in Kb and TAP1 mRNA, but an increase in TAP2 mRNA. In spleen lymphocytes an age-related increase in all three mRNA species occurred throughout life. While MHC class I and Tap genes underwent very similar age-related changes, MHC class I mRNA was about 50 times more abundant than either TAP1 or TAP2 mRNA. [source] The Role of Declarative Pointing in Developing a Theory of MindINFANCY, Issue 3 2004Luigia Camaioni It has been suggested that the child's capacity to represent and influence another person's attentional state about an object or event in triadic interactions (declarative communication) is an early manifestation of social understanding in the second year of life. This study tested the following predictions: First, in typically developing children declarative pointing emerges later than imperative pointing. Second, the capacity to use declarative pointing is linked to the understanding of other's intentions (i.e., to the capacity to reproduce other's intended acts after seeing failed attempts to perform these acts). The study was conducted in 2 phases. In the first phase, the parents of 133 typically developing infants completed the Questionnaire on Pointing Gesture, which allowed the identification of babies able to use pointing in familiar contexts. Of these children, 40 participated in the experiment and were tested on 2 tasks: a new task designed to elicit production and comprehension of imperative and declarative pointing, and a modified version of Meltzoff's (1995) task designed to assess understanding of others' intentions. Tasks were administered to each participant in 2 sessions carried out at 3-month intervals. Children were 12 months old on average at the 1st session and 15 months old on average at the 2nd session. Results showed that children produced and understood declarative pointing later than imperative pointing. Furthermore, production of declarative pointing was clearly linked to understanding of others' intentions. No relation was found between production and comprehension of imperative pointing and intention understanding. Implications from the association between declarative pointing and inferring other's intentions are discussed. [source] Focused attention in toddlers: measurement, stability, and relations to negative emotion and parentingINFANT AND CHILD DEVELOPMENT, Issue 4 2008Bridget M. Gaertner Abstract This longitudinal study examined individual differences and correlates of focused attention when toddlers were approximately 18 months old (T1; n=256) and a year later (T2; n=230). Toddlers' attention and negative emotionality were reported by mothers and non-parental caregivers and rated globally by observers. Toddlers' focused attention also was observed during two mother,child interactions and an independent play task. Measures of maternal emotional support and control were obtained via self-report and observation. Some contemporaneous relations among indices of toddlers' attention were obtained, particularly for observed measures. Moreover, all measures of attention demonstrated stability across time. Negative emotionality was negatively related to toddlers' observed attention at both ages, whereas maternal praise had positive concurrent associations. Maternal control was negatively related to observed attention at T2 and also predicted longitudinally, but only for children who initially had low or moderate attention. The findings suggest that individual differences in focused attention evidence stability early in life but can be influenced by adult socialization. Copyright © 2008 John Wiley & Sons, Ltd. [source] Child care before 6 months of age: a qualitative study of mothers' decisions and feelings about employment and non-maternal careINFANT AND CHILD DEVELOPMENT, Issue 5 2006Penelope Leach Abstract Employment of women while their children are infants has increased in the UK in the last decade. This study of 57 employed mothers of infants less than seven months old examined their retrospective reports of planning child care and their contemporaneous feelings about the child care they were using, based on qualitative interviews. Issues addressed included mothers' reasons for returning to employment at that time, their theoretical preferences among a range of child care types and providers and the process of making actual choices, including the range and types of advice received and the involvement of fathers. Mothers were also encouraged to discuss their feelings about how child care was working out once the infant was settled. Continuing concerns expressed by mothers included the importance of open communication with caregivers, their desire to keep control over infants' daily lives and upbringing, worries about infants' safety and concerns about the levels of cognitive stimulation they received. Copyright © 2006 John Wiley & Sons, Ltd. [source] Young infants' vocalizations towards mother versus stranger: associations with the infant,mother relationshipINFANT AND CHILD DEVELOPMENT, Issue 5 2005Susanne Völker Abstract Infants' differential vocal response (DVR) towards their mother and a female stranger at 3 months of age has been predominantly investigated as an index of early cognitive functioning. The present study explored the relationship between DVR and different infant and mother indicators of the developing relationship quality in a sample of 23 mother,infant dyads. Mother,infant interactions and stranger,infant interactions were videotaped during home visits when the infants were 3 months old. At the age of 12 months, infants' behaviour was assessed in the Ainsworth's strange situation. In both assessments, mothers noted the infants' behavioural states on 3 successive days. Results revealed a specific relation between DVR and the emotional atmosphere of the early mother,infant interaction. Particularly, DVR was less pronounced in favour of the mother when the mother displayed emotional expressions defined as rejection. DVR is discussed as an index that may indicate both infant emotional engagement and infant cognitive competencies. Copyright © 2005 John Wiley & Sons, Ltd. [source] Enhancing mothers' interactions with toddlers who have sensory-processing disordersINFANT MENTAL HEALTH JOURNAL, Issue 3 2010Nurit Jaegermann The objective of the current study was to examine the effects of a brief Mediational Intervention for Sensitizing Caregivers (the MISC-SP) designed to enhance the quality of mothers' interaction with their toddlers who have sensory processing disorders (SPD). The basic assumption was that quality parent,child interactions can serve as a protective factor moderating the potential negative effects of toddlers' sensory processing and regulation difficulties on their development. The effects of the intervention were compared to those of another intervention designed to enhance children's sensory functioning (the SI group) and to a control group receiving no intervention. Participants were 86 toddlers (12,18 months old) with SPD and their mothers, who were randomly assigned to the aforementioned three research groups. Following the intervention period, mothers in the MISC-SP group showed more sensitive behavior, supported their toddlers' communication behavior better, and used teaching behaviors more appropriately than did mothers in the two other groups. [source] The role of maternal responsiveness in predicting infant affect during the still face paradigm with infants born very low birth weightINFANT MENTAL HEALTH JOURNAL, Issue 2 2008Sarah J. Erickson There is limited empirical literature addressing infants' response to a standardized stressor with infants born very low birth weight (VLBW). The purpose of this study was to assess the relative strength of maternal responsiveness in predicting infant affect in response to the Still Face (SF) paradigm in a cross-sectional cohort of ethnically diverse infants born VLBW and their mothers (N = 50; infants 6,8 months old). Infant affect and maternal responsiveness were coded in 1-s intervals while dyads participated in the SF. In addition, perinatal medical status, developmental status, and infant temperament were assessed. Findings revealed that positive infant affect during and after the SF stressor were strongly associated with baseline infant positive affect and maternal responsiveness at the reunion episode, respectively. In contrast, when predicting negative infant affect during and after the SF stressor, prior infant negative affect was strongly and uniquely significant. Infant positive affect, negative affect, and maternal responsiveness were not significantly associated with gender, infant perinatal medical history, developmental status, or temperament. Future research is warranted to determine how these findings relate to infants' stress reactions in naturalistic settings and if relationship-focused interventions may reverse infant negative emotionality, enhance positive emotionality, and thereby improve self-regulation and longer term social and cognitive developmental outcomes in medically at-risk infants. [source] Attachment, culture, and the caregiving system: The cultural patterning of everyday experiences among Anglo and Puerto Rican mother,infant pairsINFANT MENTAL HEALTH JOURNAL, Issue 1 2003Vivian J. Carlson This investigation focuses on cultural differences in the relationship between maternal sensitivity, emotional expression, and control strategies during the first year of life and infant attachment outcomes at 12 months. Participants were middle-class Puerto Rican and Anglo mother,infant pairs (N = 60). Ratings of physical control, emotional expression, and maternal sensitivity during mother,infant interactions in five everyday home settings, videotaped when the infants were 4, 8, and 12 months old, were examined in combination with 12-month Strange Situation classifications. Results suggest that physical control shows a different pattern of relatedness to maternal sensitivity, emotional expression, and attachment outcomes among the Puerto Rican compared to the Anglo mothers in this study. These findings have implications for practitioners and researchers interested in normative parenting among diverse cultural groups. ©2003 Michigan Association for Infant Mental Health. [source] A pediatric screening instrument to detect problematic infant,parent interactions: Initial reliability and validity in a sample of high- and low-risk infantsINFANT MENTAL HEALTH JOURNAL, Issue 4 2001Barbara H. Fiese The purpose of this study was to determine the initial reliability and validity of a screening instrument developed to detect problematic interactions between infants and parents as part of a pediatric well-baby exam. Participants included 117 infant,mother dyads (57 preterms and 60 full terms) assessed when infants were 6 to 9 months old. Mothers and infants were observed playing an interactional game such as peek-a-boo during the course of the pediatric exam. The game was scored for degree of interactional reciprocity using the Pediatric Infant Parent Exam (PIPE). Acceptable levels of interrater reliability were achieved. As predicted, higher risk infants and their mothers exhibited more problematic interactions than lower risk infants and their mothers. Results indicated that the PIPE was a reliable means of screening for interactional difficulties, that was sensitive to, but not synonymous with, neonatal health indices. ©2001 Michigan Association for Infant Mental Health. [source] Growth of the tufted-tailed ratINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2007Vololomboahangy R. RANDRIANJAFY Abstract Eliurus myoxinus (Rodentia: Nesomyidae, Nesomyinae) is one of the four species of endemic Malagasy rodents known to exist in the Ankarafantsika National Park, northwestern Madagascar. In order to study growth parameters and to determine at which age E. myoxinus commences breeding, we used two different techniques: captive breeding and a capture-mark-release field program in the species' natural habitat. The data collected on the breeding of E. myoxinus in captivity demonstrated that females can give birth to a litter of up to four pups, with up to four litters per calendar year. Reproduction of E. myoxinus was more likely to be continuous in captivity than under natural habitat conditions. If parturition failed, then post-partum mating occurred. Pups had a rapid linear growth phase from birth until 1 month of age. Between 1.5 and 2 months of age, the growth rate continued to increase, but then decreased at around the time of weaning, which occurred by 3.5 months of age. The successive maximum method of age determination showed that individuals at the "young" stage had an average body length of 90 mm and a weight of 30 g and were between 1.5 and 2 months old. The greatest variation in measurements of juveniles occurred at the age of 3.5 months. At this stage, sub-adults resembled adults but their external genitalia were not well developed. Individuals were classified as adults if they had reached a body length of 110 mm and a body weight of 40 g. This occurred at more than 4.5 months of age when the animals were generally reproductively active. The Vo n Bertalanffy method indicated that individuals reach the adult stage by 6 to 7 months. Males grew more rapidly than females, reaching adulthood by 5.5 months of age, whereas females only reached adulthood several weeks later. This species is polygamous. The sex ratio of pups at birth favored females by approximately 3:1. The higher proportion of female pups at birth may represent a survival strategy of this species, possibly associated with ecological conditions. [source] Transplanted XY germ cells produce spermatozoa in testes of XXY mice,INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2010Y. Lue Summary XXY mouse has been characterized as an experimental model for men with Klinefelter's syndrome (XXY male phenotype). To test whether donor XY germ cells could proliferate and differentiate in the XXY testicular environment, donor testicular cells from adult (2,3 months old) and immature (10 days old) XY green fluorescence protein (GFP) transgenic mice were transplanted into the seminiferous tubules of adult (4,7 months old) and young (6 weeks old) XXY recipient mice respectively. Twelve weeks after transplantation, GFP positive spermatogonia were found in 21.74% (five out of 23) of adult XXY recipients who received adult donor cells. The GFP positive segments of seminiferous tubules were observed in 44.44% (four out of nine) young XXY recipients who received donor cells from 10 days old GFP mice. We found using immunohistochemistry and cell morphology that donor-derived GFP positive germ cells were spermatogonia, spermatocytes, round spermatids and spermatozoa in some of the seminiferous tubules of young XXY recipient mice. The results demonstrated that the donor XY germ cells were able to qualitatively complete spermatogenesis in some of the seminiferous tubules of XXY mice. [source] Evaluation of a magnetic resonance biomarker of osteoarthritis disease progression: doxycycline slows tibial cartilage loss in the Dunkin Hartley guinea pigINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2009Jonathan Bowyer Summary The objective was to assess the effect of doxycycline treatment on a magnetic resonance imaging (MRI) biomarker of cartilage volume loss, and on matrix metalloproteinase (MMP) activity in a guinea pig osteoarthritis model. Guinea pigs (9 months old) were dosed with vehicle or doxycycline, 0.6, 3.0 mg/kg/day for 66 days. Fat-suppressed 3D gradient-echo MRI of the left knee was acquired pre- and post dosing. Change in medial tibial plateau (MTP) cartilage volume (MT.VC) was determined using image analysis. At termination, MTP cartilage was removed from knees and proteolytic MMP activity determined using a fluorescent peptide substrate assay. Vehicle-treated animals lost 20.5% (95% CI mean 25.6,15.1) MT.VC. The doxycycline (0.6 mg/kg/day) group lost 8.6% (P < 0.05, 95% CI 20.6 to ,5.3) whilst the 3.0 mg/kg/day group lost 10.0% (P < 0.05, 95% CI 13.9,6.0%). Endogenous levels of active MMPs were below limits of detection in all samples. However, doxycycline treatment ablated amino phenyl mercuric acid activated MMP-13 and MMP-8 levels, reduced MMP-9 levels by 65% and MMP-1 levels by 24%. Doxycycline treatment resulted in partial protection from MT.VC loss and was associated with complete reduction in MMP-13 and MMP-8, and partial reduction in MMP-9 activity. These data imply a role of MMPs in cartilage degeneration but incomplete protection suggests that additional doxycycline insensitive mechanisms are important in this model. The protective effect of doxycycline correlates with the clinical finding of lessened joint space narrowing, strengthens the utility of this animal model in identifying disease-modifying osteoarthritic drugs and supports the use of MRI biomarkers of cartilage loss. [source] | ||||||||||||||||||||||||||||||||||||||||