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1.
Phys Rev E ; 105(1): L012603, 2022 Jan.
Article in English | MEDLINE | ID: mdl-35193255

ABSTRACT

We derive the three-loop order renormalization group equations that describe the flat phase of polymerized membranes within the modified minimal subtraction scheme, following the pioneering one-loop order computation of Aronovitz and Lubensky [Phys. Rev. Lett. 60, 2634 (1988)10.1103/PhysRevLett.60.2634] and the recent two-loop order one of Coquand, Mouhanna, and Teber [Phys. Rev. E 101, 062104 (2020)2470-004510.1103/PhysRevE.101.062104]. We analyze the fixed points of these equations and compute the associated field anomalous dimension η at three-loop order. Our results display a marked proximity with those obtained using nonperturbative techniques and reexpanded in powers of ε=4-D. Moreover, the three-loop order value that we get for η at the stable fixed point, η=0.8872, in D=2, is compatible with known theoretical results and within the range of accepted numerical values.

2.
Phys Rev E ; 106(6-1): 064114, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36671185

ABSTRACT

We study quenched disordered polymerized membranes in their flat phase by means of a three-loop perturbative analysis performed in dimension D=4-ε. We derive the renormalization group equations at this order and solve them up to order ε^{3}. Our results confirm those obtained by Coquand et al. within a nonperturbative approach [Phys. Rev. E 97, 030102(R) (2018)PREHBM2470-004510.1103/PhysRevE.97.030102] predicting a finite-temperature, finite-disorder wrinkling transition and those obtained by Coquand and Mouhanna within a recent two-loop order approach [Phys. Rev. E 103, L031001 (2021)PREHBM2470-004510.1103/PhysRevE.103.L031001], while correcting some of the results obtained in this last reference. We compute the anomalous dimensions that characterize the scaling behavior at the various fixed points of the renormalization group flow diagram. They appear to be in strong agreement with those predicted within the nonperturbative context.

3.
Poult Sci ; 85(7): 1245-58, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16830866

ABSTRACT

The aim of this study was to compare and relate plasma hormone levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), estradiol (E2), and the in vitro P4 production capacity of the largest yellow (F1) follicle granulosa cells with the laying performance of 2 genotypes (a standard S line and a dwarf cross-experimental E line) maintained under ad libitum (SA, EA) or restricted (SR, ER) feeding regimens. Age-related hormone changes were determined from 4 to 50 wk, hormone changes during the ovulatory cycle were determined during lay, and changes in follicle granulosa cell P4-producing capacity in response to LH with or without growth factors were measured in vitro at different ages. The mean laying rate was similar for SR, EA, and ER but were lower for the SA. Plasma LH and FSH concentrations increased with age in all groups and peaked at puberty. Restricted feeding delayed puberty in both genotypes. Concentrations of E2 and P4 increased after puberty in all groups but delayed in restricted hens. Plasma levels of LH, FSH, P4, and E2 before and after puberty were not correlated with egg-laying performance, but peak E2 levels were. Luteinizing hormone and P4 concentrations during the ovulatory cycle showed differences that may be associated with the different laying performances of the 2 genotypes under ad libitum and restricted feeding. The increase in plasma LH concentration (from basal) during the preovulatory surge was higher in the SR than in the SA but was similar for EA, ER, and SA. The increase in P4 was also higher in SR than in the SA with no difference between EA and ER. In vitro P4 production by granulosa cells in response to LH with insulin-like growth factors, and bone morphogenetic protein-7 was different among the SA, SR, EA, and ER; the EA, SR, and ER had greater responses, and the SA had less response. The presence of insulin-like growth factors and bone morphogenetic protein-7 enhanced LH effects depending on the feeding regimen and age of hen. This finding suggests that differences in laying performances among genotypes fed at different nutritional levels may be partly due to differences in processes associated with follicular maturation modulated by gonadotropins and growth factors. It is concluded that the age at puberty is determined mainly by feed allowance, irrespective of genotype, and that differences in laying performance may be due to a combination of factors that include changes in the levels of gonadotropins or ovarian hormones and growth factors, BW, and the condition of the different genotypes under different feeding allowances.


Subject(s)
Chickens/genetics , Chickens/physiology , Diet , Estradiol/blood , Gonadotropins, Pituitary/blood , Ovarian Follicle/physiology , Oviposition/physiology , Progesterone/blood , Aging , Animal Feed , Animals , Chickens/blood , Female , Follicle Stimulating Hormone/blood , Food Deprivation , Genotype , Luteinizing Hormone/blood , Weight Gain
4.
Poult Sci ; 85(6): 1098-103, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16776481

ABSTRACT

We investigated whether a change in peripheral glucose homeostasis, a local change in the insulin-related ovarian regulatory system, or both occurred in ad libitum-fed broiler breeder hens compared with feed-restricted counterparts. Feed-restricted (R, from 5 to 16 wk of age) and ad libitum-fed (A) hens from a standard commercial line (S) and an experimental dwarf genotype (E) were studied. Basal and stimulated plasma insulin and glucose concentrations were measured during the prebreeding and laying periods. In the basal state (after 16 h fasting) plasma glucose concentrations were significantly lower in SA chickens (-5% at 17 wk, -7.5% at 32 wk) compared with EA, SR, and ER chickens, with no difference in plasma insulin concentrations (n = 16). In 17-wk-old SA birds, 30 min after oral glucose loading, plasma glucose concentrations increased significantly compared with the basal state and were also significantly lower as compared with SR but did not differ significantly from EA and ER. Plasma insulin concentrations did not differ significantly between genotypes or regimens (n = 16). A potential modification of intracellular mediators involved in the regulation of cell growth and survival in small follicles that were overrecruited in SA compared with SR was also investigated in SA and SR hens at 32 wk. There was no effect of food restriction in phospho-Akt, Akt, phospho-ERK, and phospho-S6 in the small white ovarian follicles (n = 6) in the basal state and after 30 min of refeeding. In conclusion, the present study does not demonstrate any evidence of glucose intolerance during the prebreeding period, specific change in the ovarian small follicle insulin signalling pathway, or both, in laying broiler breeders fed ad libitum compared with feed-restricted hens.


Subject(s)
Blood Glucose/metabolism , Chickens/physiology , Diet , Insulin/pharmacology , Ovary/drug effects , Animals , Blood Glucose/analysis , Breeding , Chickens/genetics , Extracellular Signal-Regulated MAP Kinases/metabolism , Fasting , Female , Food , Genotype , Glucose Tolerance Test/veterinary , Homeostasis , Insulin/blood , Ovary/enzymology , Ovary/physiology , Oviposition , Phosphorylation , Proto-Oncogene Proteins c-akt/metabolism , Ribosomal Protein S6 Kinases/metabolism
5.
Poult Sci ; 84(2): 298-306, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15742967

ABSTRACT

Ad libitum feeding reduces livability and reproductive fitness in broiler breeder hens. Two genotypes, a standard (S) and an experimental dwarf broiler breeder (E), were fed ad libitum (SA and EA, respectively), restricted at 55% of ad libitum feed intake (intermediate restriction) from 6 to 15 wk of age (SI and EI, respectively), or restricted (SR and ER, respectively) to match a standard growth curve with a diluted mash feed (2,400 kcal/kg). The experiment was repeated at 2 locations (experiment 1 = 672 hens in pens from 0 to 40 wk; experiment 2 = 420 hens in pens and cages from 0 to 53 wk). Feed restriction reduced adult BW by 20% compared with ad libitum feeding, delayed sexual maturity by 2 to 4 wk, and improved livability. Hens fed the intermediate diet immediately compensated after 15 wk of age to reach BW, sexual maturity, and livability close to those of ad libitum-fed hens. The E genotype exhibited better tolerance to ad libitum feeding than the S genotype in all measured aspects. Average laying rate during the first 24 wk of lay was 66.4, 77.4, 69.9, 47.2, 57.9, and 72.4% for EA, EI, ER, SA, SI, and SR respectively in experiment 2. Egg abnormalities (double yolk, shell problems) decreased after the peak of lay but remained consistently higher for S compared with E, and for ad libitum and intermediate diets compared with the restricted diet. Yolk deposition rate was measured by a double dye technique. Duration of yolk rapid growth was 8.8 d in E and 9.3 d in S hens (P < 0.001), but this difference did not explain the observed variations in laying rate. The potential to increase feed allowances even with a diluted diet in broiler breeder hens requires adapted genotypes.


Subject(s)
Chickens/genetics , Diet/veterinary , Aging , Animal Nutritional Physiological Phenomena , Animals , Egg Yolk/physiology , Female , Food Deprivation , Genotype , Oviposition , Ovum/physiology , Weight Gain
6.
Br Poult Sci ; 45(5): 695-703, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15623225

ABSTRACT

(1) Tolerance to ad libitum feeding was compared in three genotypes of broiler breeder hens: a standard broiler breeder fed ad libitum (SA) or restricted (SR), a slow growing 'label' broiler breeder (L) and an experimental dwarf heavy broiler breeder (E). Two similar experiments were conducted in two distinct research centres. (2) Feed intake and body weight were measured every 3 weeks from hatch to 40 to 49 weeks of age. Egg production and egg abnormalities were recorded. The number of yellow follicles in ovaries was counted at the age of 32 weeks. (3) Body weight was stabilised at 2.2, 3.7 and 5.4 kg after 24 weeks of age in L, E and SA hens, respectively. Growth of the SR hens was similar to that of L up to 20 weeks and stabilised at a similar level to that of E hens after 30 weeks of age. (4) Sexual maturity was delayed by 6 weeks in restricted breeders compared to ad libitum fed hens that started to lay at 20 weeks. SA hens had low egg production and a high proportion of defective eggs, which was largely compensated for by feed restriction. However, productivity of SR hens remained lower than that of L breeders. (5) Compared to the low viability and reproductive fitness observed with SA hens, the E dwarf broiler breeder tolerated ad libitum feeding and had better egg production, fewer egg abnormalities and yellow follicles per ovary and a higher egg production. However, laying rate was still lower than that of the SR and L groups. Energy conversion (kJ/g egg) from 32 to 40 weeks of age was much higher in the SA group than in the other three groups. 6. The feasibility of feeding a dwarf broiler breeder ad libitum calls for further research on implications of specific IGF and GH-receptor expression at the level of the ovary in dw chickens.


Subject(s)
Chickens/physiology , Diet , Aging , Animals , Body Weight , Breeding , Chickens/anatomy & histology , Chickens/genetics , Eating , Female , Genotype , Ovary/anatomy & histology , Oviposition , Sexual Maturation , Species Specificity
7.
Anim Reprod Sci ; 82-83: 321-39, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15271463

ABSTRACT

When mammalian spermatozoa exit the testis, they show a highly specialized morphology; however, they are not yet able to carry out their task: to fertilize an oocyte. This property, that includes the acquisition of motility and the ability to recognize and to fuse with the oocyte investments, is gained only after a transit through the epididymis during which the spermatozoa from the testis travel to the vas deferens. The exact molecular mechanisms that turn these cells into fertile gametes still remain mysterious, but surface-modifying events occurring in response to the external media are key steps in this process. Our laboratory has established cartographies of secreted (secretomes) and present proteins (proteomes) in the epididymal fluid of different mammals and have shown the regionalized variations in these fluid proteins along the epididymis. We have found that the main secreted proteins are common in different species and that enzymatic activities, capable of controlling the sperm surface changes, are present in the fluid. Our studies also indicate that the epididymal fluid is more complex than previously thought; it contains both soluble and particulate compartments such as exosome-like vesicles (epididymosomes) and certainly specific glycolipid-protein micelles. Understanding how these different compartments interplay to modify sperm components during their transit will be a necessary step if one wants to control and to ameliorate sperm quality and to obtain valuable fertility markers helpful to establish a male fertility based genetic selection.


Subject(s)
Epididymis/cytology , Fertility , Sperm Maturation/physiology , Spermatozoa/physiology , Testis/cytology , Animals , Body Fluids/chemistry , Cell Membrane/physiology , Epididymis/chemistry , Epididymis/physiology , Fertility/physiology , Male , Proteins/physiology , Proteome/physiology , Spermatozoa/ultrastructure , Vas Deferens/cytology
8.
Domest Anim Endocrinol ; 25(3): 287-94, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14550512

ABSTRACT

An evaluation of the insulin-like growth factors (IGF) system in the ovaries of heavy breeder hens during the growing phase was performed to measure the effect of feed restriction. The transcripts of IGF-I, IGF-II, IGF receptor (IGF-R), two IGF binding proteins (IGFBP-2 and IGFBP-5), GH receptor (GH-R) and insulin receptor (I-R) were measured by RT-PCR at 4, 8, 12 and 16 weeks of age in the ovaries of ad libitum fed and feed restricted hens. The transcripts of all genes screened were detected in all feed regime groups and at all ages sampled. However, no significant overall effects of feed restriction on these transcripts were found despite the marked difference in body growth (200% at 16 weeks of age). Similarly there were no significant age effects except for the expression of GH-R-that showed a decrease after 8 weeks of age (P<0.01). Although feed restriction seems to have a relatively limited effect on the expression of these components of the ovarian IGF system in juveniles, a more detailed determination is necessary to determine possible changes nearer to sexual maturity (16 weeks of age onwards). It is concluded that components of the IGF system, GH or insulin may not be involved in the mechanisms that, through restricted feeding, alter ovarian development and function during growth to enable better reproductive performance during lay.


Subject(s)
Animal Nutritional Physiological Phenomena , Chickens/growth & development , Ovary/physiology , Receptor, Insulin/metabolism , Receptors, Somatotropin/metabolism , Somatomedins/metabolism , Aging/physiology , Analysis of Variance , Animal Feed , Animals , Chickens/genetics , Chickens/metabolism , Female , Gene Expression Regulation, Developmental , Insulin-Like Growth Factor Binding Protein 2/genetics , Insulin-Like Growth Factor Binding Protein 2/metabolism , Insulin-Like Growth Factor Binding Protein 5/genetics , Insulin-Like Growth Factor Binding Protein 5/metabolism , Insulin-Like Growth Factor I/genetics , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor II/genetics , Insulin-Like Growth Factor II/metabolism , RNA, Messenger/analysis , Receptor, Insulin/genetics , Receptors, Somatomedin/genetics , Receptors, Somatomedin/metabolism , Receptors, Somatotropin/genetics , Somatomedins/genetics
9.
Biol Reprod ; 65(5): 1332-9, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11673247

ABSTRACT

The 94-kDa ram epididymal fluid form of the sperm membrane-derived germinal angiotensin I-converting enzyme (ACE) was purified by chromatography, and some of its enzymatic properties were studied. For the artificial substrate furanacryloyl-L-phenylalanylglycylglycine (FAPGG), the enzyme exhibited a Michaelis constant (K(m)) of 0.18 mM and a V(max) of 34 micromoles/(min x mg) and for hippuryl-L-histidyl-L-leucine a K(m) of 2.65 mM and a V(max) of 163 micromoles/(min x mg) under the defined standard conditions (300 mM NaCl and 50 mM Tris; pH 7.5 and 8.3, respectively). The FAPGG hydrolysis was decreased by 82.5% and 67.5% by EDTA and dithioerythritol, respectively, and was totally inhibited by specific ACE inhibitors such as captopril, P-Glu-Trp-Pro-Arg-Pro-Glu-Ile-Pro-Pro, and lisinopril. Optimum activity for FAPGG was with pH 6.0, 50 mM chloride, and 500 microM zinc. Under the various conditions tested, bradykinin, angiotensin (Ang) I, Ang II, and LHRH were competitors for FAPGG. Bradykinin and angiotensin I were the best competitors. The enzyme cleaved Ang I into Ang II, and the optimal conditions were with pH 7.5 and 300 mM chloride. The relationship between the carboxypeptidase activity in seminal plasma and the prediction of fertility of young rams was also studied. These results indicated a correlation between sperm concentration and ACE activity in semen but showed no statistically significant correlation between such activity and fertility of the animal. Finally, we tested the role of ACE in fertilization; no difference in the in vitro fertilization rate was observed in the presence of 10(-4) M captopril.


Subject(s)
Epididymis/enzymology , Peptidyl-Dipeptidase A/metabolism , Sheep , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Captopril/pharmacology , Cell Membrane/enzymology , Dithioerythritol/pharmacology , Edetic Acid/pharmacology , Fertilization in Vitro/veterinary , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Male , Oligopeptides/metabolism , Peptidyl-Dipeptidase A/physiology , Semen/enzymology , Solubility , Sperm Count , Spermatozoa/ultrastructure
10.
Biol Reprod ; 62(6): 1790-803, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10819784

ABSTRACT

Proteins present in and secreted into the lumen of various regions of the stallion epididymis were characterized qualitatively and quantitatively by two-dimensional electrophoresis. Using this proteomic approach, 201 proteins were found in the lumen and 117 were found that were secreted by the epithelium in various parts of the organ. Eighteen proteins made up 92.6% of the total epididymal secretory activity, lactoferrin (41.2%) and clusterin (24.8%) being the most abundant. Procathepsin D, HE1/CTP (cholesterol transfer protein), GPX (glutathione peroxidase), beta-N-acetyl-hexosaminidase, and PGDS (prostaglandin D2 synthase) were the other major compounds secreted. The most abundant proteins found in the luminal fluid were albumin and the secreted proteins: lactoferrin, PGDS, GPX, HE1/CTP, and hexosaminidase. Three main secretory epididymal regions were identified from the protein pattern, i.e., regions E0-E2, E3-E5, and E6-E9. Region E0-E2 was characterized by the secretion of clusterin (53%), PGDS (44%), and GPX (6%). Region E3-E5 had the highest number of secreted proteins, the highest protein concentrations (60-80 mg/ml), and the highest spermatocrit value (85%). Lactoferrin (60% in E4), clusterin (29% in E3), hexosaminidase (10% in E3), and procathepsin D (6.9% in E4) were the most abundant proteins in this region. Region E6-E9, in which few region-specific secreted compounds were found, was characterized by a high quantity of lactoferrin in the luminal fluid (2-14 mg/ml). Comparison between the secretion of the major proteins and their concentrations in the lumen throughout the organ showed that the behavior of each protein is specific, in particular for the three isoforms of clusterin.


Subject(s)
Carrier Proteins , Epididymis/metabolism , Horses/metabolism , Molecular Chaperones , Proteins/metabolism , Amino Acid Sequence , Animals , Body Fluids/chemistry , Cathepsin D/analysis , Cathepsin D/chemistry , Cathepsin D/metabolism , Clusterin , Electrophoresis, Gel, Two-Dimensional , Epididymis/anatomy & histology , Epithelium/metabolism , Glutathione Peroxidase/analysis , Glutathione Peroxidase/chemistry , Glutathione Peroxidase/metabolism , Glycoproteins/analysis , Glycoproteins/chemistry , Glycoproteins/metabolism , Horses/anatomy & histology , Intramolecular Oxidoreductases/analysis , Intramolecular Oxidoreductases/metabolism , Lactoferrin/analysis , Lactoferrin/metabolism , Lipocalins , Male , Molecular Sequence Data , Proteins/analysis , Proteome , Sequence Analysis, Protein , Sperm Count , Vesicular Transport Proteins , beta-N-Acetylhexosaminidases/analysis , beta-N-Acetylhexosaminidases/chemistry , beta-N-Acetylhexosaminidases/metabolism
11.
Am J Psychiatry ; 156(10): 1536-44, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10518163

ABSTRACT

OBJECTIVE: The Challenger space shuttle explosion in January 1986 offered an opportunity to determine what, if any, symptoms of posttraumatic stress disorder (PTSD) and bereavement normal latency-age children and adolescents would develop after a distant, horrifying event. METHOD: With a structured interview, the authors assessed the symptoms of 153 randomly selected children from Concord, N.H., and Porterville, Calif. Responses were statistically compared between East Coast children, who saw the event on television and who generally cared more about the teacher aboard Challenger, and West Coast children, who heard about it first; between latency-age children and adolescents; and between children seen 5-7 weeks later and those same children seen 14 months later. RESULTS: More than 60% of the subjects feared at least one stimulus related to Challenger within the first 5-7 weeks of the explosion. The East Coast and latency-age groups appeared significantly more symptomatic than did the West Coast and adolescent groups. Over the 14-month study period, most symptoms dramatically faded. However, adolescents' diminished expectations for the future in general increased, and latency-age children's changed approach to space careers held relatively steady. Three East Coast latency-age children met the DSM-III-R symptom requirements for PTSD in 1986; no children met these in 1987. CONCLUSIONS: Children's symptomatic patterns after Challenger relate to the patterns for PTSD listed in diagnostic manuals and to three symptoms not in the DSM-IV list. To the authors, distant traumas appear to be one of a newly defined spectrum of trauma-related conditions that include relatively evanescent symptoms and a few longer-lasting ones. These symptoms may affect large numbers of normal children.


Subject(s)
Bereavement , Explosions , Psychology, Child , Space Flight , Stress Disorders, Post-Traumatic/diagnosis , Adolescent , California/epidemiology , Career Choice , Child , Dreams , Fear , Female , Humans , Latency Period, Psychological , Life Change Events , Male , Memory , New Hampshire/epidemiology , Play and Playthings , Sampling Studies , Stress Disorders, Post-Traumatic/epidemiology , Stress Disorders, Post-Traumatic/psychology , Writing
12.
Am J Psychiatry ; 154(6): 744-51, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9167500

ABSTRACT

OBJECTIVE: The Challenger spacecraft explosion in 1986 offered an opportunity to study the thinking of normal children after a sudden and distant disaster, differences in thinking among children of different levels of emotional concern and different ages, and changes in their thinking over time. METHOD: The authors studied six thinking patterns known to characterize childhood posttraumatic stress disorder and four additional hypothesized patterns in 153 randomly selected children of Concord, N.H. (who watched the explosion on television) and Porterville, Calif. (who heard about it later). They compared the structured-interview responses of the more involved (East Coast) and less involved (West Coast) children, of the latency-age children and the adolescents, and of the children initially (5-7 weeks after the explosion) and 14 months later. RESULTS: The children exhibited the 10 predictable thinking patterns. They initially defended themselves, denying the reality of the explosion. They later fantasized about it. They tried to cope by seeking additional information on their own, at home, and at school. Most children talked about Challenger, but a minority of the latency-age youngsters avoided related talk and thoughts. The adolescents experienced more paranormal thinking, philosophical changes, and negative attitudes. Over the year, omens, paranormal experiences, and Challenger-based fantasies tended to disappear, but negative views about institutions and the world's future held steady or increased. CONCLUSIONS: The children's thinking followed predictable patterns. A higher degree of emotional involvement (East Coast children) was strongly linked to these thinking patterns, as was being an adolescent. Distant disasters appear to set up commonalities of thought that might come to characterize certain generations of children.


Subject(s)
Disasters , Psychology, Child , Space Flight , Thinking , Adaptation, Psychological , Adolescent , Attitude , Child , Denial, Psychological , Fantasy , Female , Humans , Latency Period, Psychological , Life Change Events , Male , Memory , Parapsychology , Psychiatric Status Rating Scales , Psychology, Adolescent , Stress Disorders, Post-Traumatic/diagnosis , Stress Disorders, Post-Traumatic/psychology , United States
13.
Am J Psychiatry ; 153(5): 618-25, 1996 May.
Article in English | MEDLINE | ID: mdl-8615406

ABSTRACT

OBJECTIVE: The Challenger spacecraft explosion of Jan. 28, 1986, offered an opportunity to study the memories of normal latency and adolescent children of different emotional involvements following one sudden and distant disaster. How would children of various levels of concern express their memories? And if studied over time, how would these narratives change? Would there be developmental differences? And would there be false details of memory? METHOD: The authors set out to compare the memories of 153 children from Concord, N.H. (who watched the explosion on television), and Porterville, Calif. (who heard about it). The structured-interview responses of involved and less involved children; latency-age versus adolescent children; and those seen initially (5-7 weeks after the explosion) versus those same children seen later (at 14 months) were statistically compared. RESULTS: The vast majority of children's memories of Challenger were clear, consistent, and detailed, with highlighting of personal placement, who else was there, and personal occurrences linked to the event. Those children who were less emotionally involved demonstrated significantly less clarity, consistency, and correct ordering of sequences and were less likely to remember personal placement, other people who were there, and related personal incidents. About 30% of all children in this study misunderstood something about Challenger and incorporated these misunderstandings into their memories as false details. Latency-age children continued to harbor false details for 14 months, as opposed to the adolescents. CONCLUSIONS: Childhood memories of the Challenger space shuttle explosion appeared predictable, were related to patterns of memory that have been observed following single, unrepeated traumas, and reflected age and stage differences.


Subject(s)
Emotions , Explosions , Memory , Psychology, Adolescent , Psychology, Child , Space Flight , Adolescent , Child , Child Development , Defense Mechanisms , Female , Humans , Interview, Psychological , Life Change Events , Male , Radio , Television
15.
Clin Nucl Med ; 19(4): 336-43, 1994 Apr.
Article in English | MEDLINE | ID: mdl-8004868

ABSTRACT

Exercise myocardial perfusion imaging with Tc-99m sestaMIBI is routinely used to detect underlying coronary stenoses. Ischemia is diagnosed in regions that display decreased tracer uptake during exercise as compared to rest. Tc-99m sestaMIBI SPECT images of 42 healthy volunteers were assessed both qualitatively (tomographic slices) and quantitatively (sectored polar map) for potential sources of misinterpretation. On the myocardial tomographic slices, the most common culprit artifacts were diaphragmatic attenuation and bowel interposition, which caused fixed or reversible "perfusion defects" in the inferior and posterior regions (in 19/35 abnormal segments), and artifacts related to the presence and shift of hot spots (observed in 11/28 men; in women, they were more difficult to demonstrate because of the overriding effect of breast attenuation). Hot spots shifts between exercise and rest usually resulted in pseudo-reversible defects in the anterolateral and lateral walls. The quantified polar map display of the myocardium showed a physiologic decrease in sestaMIBI activity in the basal anterolateral and basal posterolateral areas in men during exercise. There are many normal variants that may mimic coronary artery disease on tomographic sestaMIBI images. Before reporting an area of decreased activity as either a fixed or reversible perfusion defect, the interpreter should ensure that it does not represent an artifact or a normal variation in the intramyocardial distribution of sestaMIBI during exercise.


Subject(s)
Artifacts , Heart/diagnostic imaging , Technetium Tc 99m Sestamibi , Tomography, Emission-Computed, Single-Photon , Adult , Coronary Disease/diagnostic imaging , Exercise , Exercise Test , False Positive Reactions , Female , Humans , Male , Myocardial Ischemia/diagnostic imaging , Reference Values , Rest
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