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Showing papers by "Emory University published in 1989"


Journal ArticleDOI
TL;DR: Intimal hyperplasia after balloon injury is a complex process involving platelets, growth factors, endothelial cells, smooth muscle cells, mechanical injury, wall shear stress, and probably other unknown factors.
Abstract: Restenosis after successful PTCA remains a major problem limiting the efficacy of the procedure. The pathophysiologic mechanism of restenosis has been enigmatic so far, but accumulated evidence strongly suggests that intimal hyperplasia is the major mechanism. Based on current understanding of the process of intimal hyperplasia, one unifying concept may be that there are at least two major local biologic determinants influencing this process, lesion characteristics and regional flow dynamics. Lesion characteristics include the plaque structure and the quantity of smooth muscle. These may provide the anatomic substrate that determines the extent of injury and the degree of smooth muscle cell proliferation. The amount of smooth muscle cells in the stenotic lesion activated by injury to undergo proliferation may determine the eventual bulk of the restenotic lesion. In addition, low wall shear stress could promote intimal hyperplasia and cause structural change of vessels to decrease the lumen, whereas high wall shear stress exerts the opposite effects. Intimal hyperplasia after balloon injury is a complex process involving platelets, growth factors, endothelial cells, smooth muscle cells, mechanical injury, wall shear stress, and probably other unknown factors. Platelets not only contribute growth factors such as PDGF but also cause organized thrombus. Different growth factors may be involved in initiating smooth muscle cell proliferation and may come from many different sources, including smooth muscle cells, endothelial cells, and macrophages. Intact confluent endothelial cells may produce heparin sulfates and inhibit intimal proliferation; however, regenerating endothelial cells may have the opposite effect. Thus, the proliferative potential of smooth muscle cells, endothelial recovery, extent of injury, wall shear stress, and other unknown factors may all influence this process. Based on these concepts concerning the biology of restenosis, some research directions concerning potential forms of therapy are proposed.

992 citations


Journal ArticleDOI
TL;DR: The data suggest that learned nonuse does occur in select neurological patients and that this behavior can be reversed through application of a forced use paradigm.

917 citations


Journal ArticleDOI
01 Jun 1989-Nature
TL;DR: In this article, the authors investigated the aggregation of three chemically different colloidal systems under both diffusion-limited and reaction-limited aggregation conditions and provided convincing experimental evidence that the two regimes of aggregation are indeed universal.
Abstract: THE aggregation of colloidal particles is of fundamental importance in colloid science and its applications. The recent application of scaling concepts1,2 has resulted in a much deeper understanding of the structure of colloidal aggregates and the kinetics of their formation. Two distinct, limiting regimes of irreversible colloid aggregation have been identified3. Diffusion-limited colloid aggregation occurs when there is negligible repulsive force between the colloidal particles, so that the aggregation rate is limited solely by the time taken for clusters to encounter each other by diffusion. Reaction-limited colloid aggregation occurs when there is still a substantial, but not insurmountable, repulsive force beween the particles, so that the aggregation rate is limited by the time taken for two clusters to overcome this repulsive barrier by thermal activation. These regimes correspond to the limiting cases of rapid and slow colloid aggregation that have long been recognized in colloid science4. An intriguing possibility suggested by recent work is that each of these limiting regimes of colloid aggregation is universal, independent of the chemical details of the particular colloid system. Here we investigate the aggregation of three chemically different colloidal systems under both diffusion-limited and reaction-limited aggregation conditions. A scaling analysis of light-scattering data is used to compare the behaviour and provides convincing experimental evidence that the two regimes of aggregation are indeed universal.

880 citations


Journal ArticleDOI
03 Nov 1989-Science
TL;DR: A complementary DNA (cDNA) for ubiquitin carboxyl-terminal hydrolase isozyme L3 was cloned from human B cells, suggesting that a family of such related proteins exists and that their expression is tissue-specific.
Abstract: A complementary DNA (cDNA) for ubiquitin carboxyl-terminal hydrolase isozyme L3 was cloned from human B cells. The cDNA encodes a protein of 230 amino acids with a molecular mass of 26.182 daltons. The human protein is very similar to the bovine homolog, with only three amino acids differing in over 100 residues compared. The amino acid sequence deduced from the cDNA was 54% identical to that of the neuron-specific protein PGP 9.5. Purification of bovine PGP 9.5 confirmed that it is also a ubiquitin carboxyl-terminal hydrolase. These results suggest that a family of such related proteins exists and that their expression is tissue-specific.

864 citations


Journal ArticleDOI
TL;DR: The slightly lower rate of development of hypercreatininemia and the higher rate of improvement in stepped-care compared with referred-care participants is consistent with the belief that aggressive treatment of hypertension may reduce renal damage and the associated increased risk of death.
Abstract: The Hypertension Detection and Follow-up Program followed up 10,940 persons for 5 years in a community-based, randomized, controlled trial of treatment for hypertension. Participants were randomized to one of two treatment groups, stepped care and referred care. The primary end point of the study was all-cause mortality, with morbid events involving the heart, brain, and kidney as secondary end points. Loss of renal function, ascertained by a change in serum creatinine, was among these secondary events. Baseline serum creatinine concentration had a significant prognostic value for 8-year mortality. For persons with a serum creatinine concentration greater than or equal to 1.7 mg/dl, 8-year mortality was more than three times that of all other participants. The estimated 5-year incidence of substantial decline in renal function was 21.7/1,000 in the stepped-care group and 24.6/1,000 in the referred-care group. Among persons with a baseline serum creatinine level between 1.5 and 1.7 mg/dl, the 5-year incidence of decline was 113.3/1,000 (stepped care) and 226.6/1,000 (referred care) (p less than 0.01). The incidence of decline in renal function was greater in men, blacks, and older adults, as well as in those with higher entry diastolic blood pressure. Among persons with a baseline serum creatinine level greater than or equal to 1.7 mg/dl, serum creatinine concentration declined by 25% or more in 28.6% of stepped-care and 25.2% of referred-care participants. Although the incidence of clinically significant hypercreatininemia in a hypertensive population is low, an elevated serum creatinine concentration is a very potent independent risk factor for mortality. The slightly lower rate of development of hypercreatininemia and the higher rate of improvement in stepped-care compared with referred-care participants is consistent with the belief that aggressive treatment of hypertension may reduce renal damage and the associated increased risk of death.

686 citations


Journal ArticleDOI
TL;DR: It is concluded that epidermal growth factor accelerates the rate of healing of partial-thickness skin wounds and further studies are required to determine the clinical importance of this finding.
Abstract: Experimental studies in animals have demonstrated that the topical application of epidermal growth factor accelerates the rate of epidermal regeneration of partial-thickness wounds and second-degree burns. We conducted a prospective, randomized, double-blind clinical trial using skin-graft-donor sites to determine whether epidermal growth factor would accelerate the rate of epidermal regeneration in humans. Paired donor sites were created in 12 patients who required skin grafting for either burns or reconstructive surgery. One donor site from each patient was treated topically with silver sulfadiazine cream, and one was treated with silver sulfadiazine cream containing epidermal growth factor (10 micrograms per milliliter). The donor sites were photographed daily, and healing was measured with the use of planimetric analysis. The donor sites treated with silver sulfadiazine containing epidermal growth factor had an accelerated rate of epidermal regeneration in all 12 patients as compared with that in the paired donor sites treated with silver sulfadiazine alone. Treatment with epidermal growth factor significantly decreased the average length of time to 25 percent and 50 percent healing by approximately one day and that to 75 percent and 100 percent healing by approximately 1.5 days (P less than 0.02). Histologic evaluation of punch-biopsy specimens taken from the centers of donor sites three days after the onset of healing supported these results. We conclude that epidermal growth factor accelerates the rate of healing of partial-thickness skin wounds. Further studies are required to determine the clinical importance of this finding.

658 citations


Journal ArticleDOI
TL;DR: The muscle mitochondria of a patient with Kearns-Sayre/chronic external ophthalmoplegia plus syndrome were found to be completely deficient in respiratory complex I activity and partially deficient in complex IV and V activities as mentioned in this paper.
Abstract: The muscle mitochondria of a patient with Kearns-Sayre/chronic external ophthalmoplegia plus syndrome were found to be completely deficient in respiratory complex I activity and partially deficient in complex IV and V activities. Treatment of the patient with coenzyme Q10 and succinate resulted in clinical improvement of respiratory function, consistent with the respiratory deficiencies. Restriction enzyme analysis of the muscle mtDNA revealed a 4.9-kilobase deletion in 50% of the mtDNA molecules. Polymerase chain reaction analysis demonstrated that the deletion was present in the patient's muscle but not in her lymphocytes or platelets. Furthermore, the deletion was not present in the muscle or platelets of two sisters. Hence, the mutation probably occurred in the patient's somatic cells. Direct sequencing of polymerase chain reaction-amplified DNA revealed a 4977-base-pair deletion removing four genes for subunits of complex I, one gene for complex IV, two genes for complex V, and five genes for tRNAs, which paralleled the respiratory enzymes affected in the disease. A 13-base-pair direct repeat was observed upstream from both breakpoints. Relative to the direction of heavy-strand replication, the first repeat was retained and the second repeat was deleted, suggesting a slip-replication mechanism. Sequence analysis of the human mtDNA revealed many direct repeats of 10 base pairs or greater, indicating that this mechanism could account for other reported deletions. We postulate that the prevalence of direct repeats in the mtDNA is a consequence of the guanine-cytosine bias of the heavy and light strands.

487 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the persistence of a population dynamics model in the setting of a $C^0 $-semigroup which is asymptotically smooth, and provided conditions on the flow on the boundary which, given the presence of a global attractor provided by the assumption of dissipativeness, are necessary and sufficient for persistence.
Abstract: The concept of persistence reflects the survival of all components of a model ecosystem. Most of the results to date are restricted to ordinary differential equations or to dynamics on locally compact spaces. The concept is investigated here in the setting of a $C^0 $-semigroup which is asymptotically smooth. Since the equations of population dynamics often involve delays or diffusion this seems the appropriate setting. Conditions are placed on the flow on the boundary which, given the presence of a global attractor provided by the assumption of dissipativeness and asymptotic smoothness, are necessary and sufficient for persistence.

484 citations


Journal ArticleDOI
TL;DR: For example, the authors found that individuals who were reluctant to share (i.e., showed a low rate of food distribution) had a higher probability of encountering aggression when they themselves approached food possessors.

393 citations


Journal ArticleDOI
TL;DR: Data support research that suggests that reinforcing properties of cocaine are primarily mediated by DA release in the nucleus accumbens, and indicate that animals may regulate self-administration responding for cocaine in order to maintain DA levels above a certain level, yet titrate responding so that aversive effects are not produced.
Abstract: The extracellular dopamine (DA) concentration in the nucleus accumbens was measured following intravenous cocaine administration. The DA concentration increased in a dose-dependent manner following a single intravenous infusion of cocaine. The concentration of DA was observed to increase and stabilize in a schedule-dependent manner when cocaine was repeatedly administered 15-, 5- and 2.5-minute intervals. When cocaine was administered in regular intervals to animals by an experimenter or when animals self-administered cocaine. DA concentrations stabilized substantially above the basal level. These data support research that suggests that reinforcing properties of cocaine are primarily mediated by DA release in the nucleus accumbens. The data and pharmacokinetic calculations indicate that the DA concentration increases for a short period following each infusion. It then falls to a level until the animal again self-administers the drug. Animals may regulate self-administration responding for cocaine in order to maintain DA levels above a certain level, yet titrate responding so that aversive effects are not produced.

385 citations


Journal ArticleDOI
TL;DR: A dual‐compartment mathematical model is used to demonstrate the effects that changing the rates of synthesis and degradation of hypothetical mRNAs and proteins would have on the final concentation of protein and suggests single exons may encode structural features that cause both mRN as and proteins to be labile.
Abstract: How important is the stability of gene products in the process of gene expression? We use a dual-compartment mathematical model to demonstrate the effects that changing the rates of synthesis and degradation of hypothetical mRNAs and proteins would have on the final concentration of protein. The model predicts that the concentration of protein at steady state equals the product of the rate constants for synthesis of mRNA and protein (ks1 and ks2) divided by the product of the rate constants for degradation (kd1 and kd2) and that the rate at which protein concentration changes depends on the rate constants for degradation of both the mRNA and the protein. This permits great flexibility in controlling induction kinetics for particular gene products, since their synthesis, translation, and degradation may be regulated coordinately to permit induction to be stable or transient or to amplify the final yield of protein. We suggest single exons may encode structural features that cause both mRNAs and proteins to be labile, thereby ensuring that modal stabilities of highly regulated macromolecules are similar.

Journal ArticleDOI
TL;DR: Spontaneous coronary artery dissection should be considered in the differential diagnosis of any young person sustaining an acute myocardial infarction, especially women in the postpartum state, and those found to be idiopathic are identified.
Abstract: Spontaneous coronary artery dissection is rare. In comparison with the usual myocardial infarction population, it occurs in relatively young people with a striking predilection for women. Of 83 cases that have been described, 62 were diagnosed at autopsy and 21 were found antemortem. A series of 11 patients with the antemortem diagnosis of spontaneous coronary artery dissection is reported and follow-up is provided for 16 of the 21 previously reported cases. Of the 62 autopsy cases, 10 (16%) were men (mean age 47) and 52 (84%) were women (mean age 40). Dissection of the left anterior descending coronary artery predominated in this group of patients, occurring in 80% of men and 65% of women. Of the 32 cases diagnosed antemortem, 15 (47%) were men (mean age 46) and 17 (53%) were women (mean age 38). Men were found to have dissection predominantly of the right coronary artery (73%). Women were found to have dissection predominantly of the left coronary artery system (88%). The etiology of spontaneous coronary artery dissection remains unclear. The 3 groups that can be identified are those associated with atherosclerotic coronary artery disease, those in the postpartum period and those found to be idiopathic. Of the 94 known cases, 69 (73%) occurred in women; 21 (31%) of these were associated with the postpartum state. The prognosis of patients surviving the initial event is good, with an 82% survival rate (follow-up: range 1.5 to 144 months, mean 38). The indications for medical or surgical treatment are presented. Spontaneous coronary artery dissection should be considered in the differential diagnosis of any young person sustaining an acute myocardial infarction, especially women in the postpartum state.

Journal ArticleDOI
T R Nichols1
TL;DR: The results suggest that the knee and ankle joints become more tightly linked mechanically at high forces since the stiffness of the biarticular gastrocnemius muscle predominates over that of the uniarticular soleus.
Abstract: 1. Mechanical actions of heterogenic (intermuscular) reflexes arising from proprioceptors in flexor and extensor ankle muscles were measured in intercollicular and premammillary decerebrate cats. Length inputs were applied to the freed tendons of one of a pair of muscles crossing the ankle joint and resulting changes in force in both muscles were measured. Interactions between autogenic and heterogenic reflexes were studied by applying length changes to both muscles. 2. A consistent asymmetry was observed in the heterogenic inhibition between the single-joint antagonists soleus and tibialis anterior (TA). Inhibition from soleus to TA was weak or absent during the reflex activation of TA. In contrast, a strong heterogenic inhibition was consistently observed from TA to soleus during the activation of soleus by a crossed-extension reflex. The effect of this inhibition in the intact joint is to increase the apparent mechanical stiffness of soleus. 3. Mutual synergism among soleus, medial gastrocnemius (MG) and lateral gastrocnemius (LG) was demonstrated only at low to moderate forces by the observation of excitatory reflexes among them. During a naturally or electrically evoked crossed-extension reflex, however, a unidirectional inhibitory reflex from MG and LG to soleus was observed. This inhibition increased with force in MG or LG. These results suggest that the knee and ankle joints become more tightly linked mechanically at high forces since the stiffness of the biarticular gastrocnemius muscle predominates over that of the uniarticular soleus. 4. Under quiescent conditions (no resting muscle activation), mutual synergism was obeyed among the ankle extensors soleus, LG and MG and also between the pretibial flexors TA and extensor digitorum longus (EDL). Moreover, inhibition was generally observed between a pretibial flexor and an ankle extensor. Departures from this expected pattern of heterogenic reflexes occurred when the muscle groups were activated by crossed-extension and flexion reflexes. Reflexes onto soleus, TA and EDL reversed in sign or increased in magnitude. 5. The observed patterns of reflex connectivity among the ankle flexors and extensors were similar in both intercollicular and premammillary preparations, although changes in reflex strength were sometimes noted in cases where a second, lower transection was performed during the experiment. 6. It is argued from the large magnitudes of certain heterogenic reflexes that the mechanical response properties of muscles crossing the ankle joint in the intact animal are not dominated by autogenic reflexes and intrinsic mechanical properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Journal ArticleDOI
TL;DR: The hypothesis that TBNVs progress according to this model is tested and some variation in interstage transition patterns are due to a progression imperative, although not all firms progressed as expected.
Abstract: This paper presents a stage of growth model for technology based new ventures TBNVs. TBNVs are postulated to evolve through four discrete stages of growth-Conception and Development, Commercialization, Growth, and Stability. Based on a longitudinal sample of 71 ventures in the computer and electronics industries, the hypothesis that TBNVs progress according to this model is tested using the del procedure for prediction analysis of cross-classification tables. The hypotheses are supported, although not all firms progressed as expected. These results suggest that some variation in interstage transition patterns are due to a progression imperative.

Journal ArticleDOI
02 Nov 1989-Nature
TL;DR: Homologies of the sequence of twit-chin have unexpected similarities to the sequences of proteins of the immunoglobulin superfamily, cell adhesion molecules and vertebrate muscle proteins, including myosin light-chain kinase, which indicate that the protein is involved in a novel mechanism of myOSin regulation.
Abstract: The Caenorhabditis elegans gene unc-22 encodes a very large muscle protein, called twitchin, which consists of a protein kinase domain and several copies of two short motifs. The sequence of twit-chin has unexpected similarities to the sequences of proteins of the immunoglobulin superfamily, cell adhesion molecules and vertebrate muscle proteins, including myosin light-chain kinase. These homologies, together with results from earlier genetic and molecular analyses, indicate that twit-chin is involved in a novel mechanism of myosin regulation.

Journal ArticleDOI
TL;DR: Only grafts containing TH-expressing fibroblasts were found to reduce rotational asymmetry and have general implications for the application of gene therapy to human neurological disease and specific implications for Parkinson disease.
Abstract: Rat fibroblasts were infected with a retroviral vector containing the cDNA for rat tyrosine hydroxylase [TH; tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2]. A TH-positive clone was identified by biochemical assay and immunohistochemical staining. When supplemented in vitro with pterin cofactors required for TH activity, these cells produced L-dopa and released it into the cell culture medium. Uninfected control cells and fibroblasts infected with the TH vector were grafted separately to the caudate of rats with unilateral 6-hydroxydopamine lesions of the nigrostriatal pathway. Only grafts containing TH-expressing fibroblasts were found to reduce rotational asymmetry. These results have general implications for the application of gene therapy to human neurological disease and specific implications for Parkinson disease.

Journal ArticleDOI
TL;DR: One of the most complete statistical descriptions to date of the natural history of HIV infection is presented, using a staged Markov model to estimate the distribution and mean length of the incubation period for acquired immunodeficiency syndrome (AIDS).
Abstract: We use a staged Markov model to estimate the distribution and mean length of the incubation period for acquired immunodeficiency syndrome (AIDS) from a cohort of 603 human immunodeficiency virus (HIV) infected individuals who have been followed through various stages of infection. The model partitions the infected period into four progressive stages: (1) infected but antibody-negative; (2) antibody-positive but asymptomatic; (3) pre-AIDS symptoms and/or abnormal haematologic indicator; and (4) clinical AIDS. We also model a fifth stage: death due to AIDS. The estimated mean (median) waiting times in each stage of infection are stage 1, 2.2 (1.5) months; stage 2, 52.6 (36.5) months; stage 3, 62.9 (43.6) months; and stage 4, 23.6(16.3) months. We estimate the mean AIDS incubation period (from infection to development of clinical AIDS) as 9.8 years with a 95 per cent confidence interval of [8.4, 11.2] years. The paper also considers the estimated density function of the AIDS incubation period and the estimated survival functions for individuals in each stage of infection. This work represents one of the most complete statistical descriptions to date of the natural history of HIV infection.

Journal ArticleDOI
01 Jan 1989-Blood
TL;DR: The effects of rhIL-3, rhGM-CSF, and rhG-CSf on the clonal growth of human colon adenocarcinoma cell lines HTB-38, WiDr, and CCL 187 are described.

Journal ArticleDOI
TL;DR: While sphingosine has appeared to be a relatively potent and specific inhibitor of protein kinase C in the systems studied, recent findings with the epidermal growth factor receptor indicate that it may serve as a pleotrophic modulator of cell functions.

Journal ArticleDOI
D. B. Glass1, Heung-Chin Cheng1, L. Mende-Mueller1, J. Reed1, D. A. Walsh1 
TL;DR: It is concluded that Ser13 and/or Gly 14, Gly14, Gly17, Asn20, and Ile22 each contribute important features to the binding of these inhibitory peptides to the protein kinase, either by providing recognition determinants, inducing structure, and/ or allowing essential peptide backbone flexibility.

Journal ArticleDOI
TL;DR: Partial zona dissection, a method using mechanical force to open the human zona pellucida, and zona drilling, which uses acidic Tyrode's medium, were compared in 1-day-old oocytes prior to reinsemination, resulting in twin pregnancies.

Journal ArticleDOI
TL;DR: The findings establish that the major structural features required for inhibition of protein kinase C and cellular processes dependent on this enzyme are the presence of a free amino group and an aliphatic side chain and that other groups have more subtle effects.
Abstract: Sphingosine, sphinganine, and other long-chain (sphingoid) bases inhibit protein kinase C in vitro and block cellular responses to agonists that are thought to act via this enzyme. To gain further insight into the mechanism of this inhibition, a series of long-chain analogues differing in alkyl chain length (11-20 carbon atoms), stereochemistry, and headgroup were examined for (a) inhibition of protein kinase C activity in vitro, (b) the neutrophil respiratory burst in response to phorbol myristate acetate (PMA), (c) the PMA-induced differentiation of HL-60 cells, and (d) the growth of Chinese hamster ovary cells. In every instance, the effects were maximal with the 18-carbon homologues, which are the same length as the predominant naturally occurring long-chain base (sphingosine). The lower potency of the shorter chain homologues was partially due to decreased uptake by cells. Small differences were obtained with the four stereoisomers of sphingosine (i.e., D and L forms of erythro- and threo-sphingosine), with N-methyl derivatives of the different sphingosine homologues, and with simpler alkylamines (e.g., stearylamine). The potency of the different headgroup analogues may be affected by the degree of protonation at the assay pH. The pKa of sphingosine was measured to be 6.7; the pKa varied among the analogues. These findings establish that the major structural features required for inhibition of protein kinase C and cellular processes dependent on this enzyme are the presence of a free amino group and an aliphatic side chain and that other groups have more subtle effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: Overall, hepatic resection appears to be an important means of curing patients with metastatic colorectal cancer isolated to the liver, and it seems imperative that all patients with hepatic metastases be evaluated by an experienced hepatic surgeon for a curative resection.

Journal ArticleDOI
TL;DR: It is concluded that when it is vital to know the precise number, size, and location of focal hepatic lesions before tumor resection, CTAP has the highest sensitivity, but MR imaging is an important adjuvant.
Abstract: Forty-three patients with known primary or secondary neoplastic involvement of the liver underwent evaluation to determine the number, size, and location of focal lesions before possible tumor resection. Imaging studies included computed tomography (CT) during arterial portography (CTAP), delayed CT, and magnetic resonance (MR) imaging at various pulse sequences. Results of radiologic studies were compared with surgical and pathologic findings. In the combined group of surgical and nonsurgical patients, CTAP was significantly more sensitive (85%) than all other techniques except 1.5-T T2-weighted spin-echo imaging (64%). Combining the information from all MR pulse sequences yielded a cumulative sensitivity of 68%. Combining the information from two modalities yielded sensitivity of 96% for CTAP plus MR imaging, 85% for CTAP plus delayed CT, and 77% for delayed CT plus MR imaging. The authors conclude that when it is vital to know the precise number, size, and location of focal hepatic lesions before tumor...

Journal ArticleDOI
TL;DR: It is suggested that endothelin causes a robust stimulation of the diacylglycerol/protein kinase C pathway in cultured vascular smooth muscle cells, and that this mechanism may contribute importantly to the physiologic events stimulated by endothelins in intact blood vessels.

Journal Article
TL;DR: Careful attention to quality control, utilization of motion detectors, and familiarization with potential artifacts will improve the specificity and diagnostic accuracy of 201TI SPECT for coronary artery disease.
Abstract: Artifacts are produced in 201TI cardiac single photon emission computed tomography (SPECT) imaging because of a variety of causes including soft-tissue attenuation, overlying abdominal viscera, variable myocardial thickness, left bundle branch block, cardiac rotation, patient motion, and technical errors. Careful attention to quality control, utilization of motion detectors, and familiarization with potential artifacts will improve the specificity and diagnostic accuracy of 201TI SPECT for coronary artery disease.

Journal ArticleDOI
Robyn Fivush1
TL;DR: This article explored the ways in which mothers and their 30-35-month-old children discussed the emotional aspects of past experiences and found that, with daughters, mothers focus more on positive emotions and tend not to attribute negative emotions to the child.
Abstract: In this study, the ways in which mothers and their 30–35-month-old children discussed the emotional aspects of past experiences was explored. Although previous research has established that children this age talk about emotions, and some studies have found sex differences between mother-daughter and mother-son dyads in these conversations, no study has examined explicitly the way in which emotions about the past are discussed. This is an important research question because emotional aspects of events may help provide an evaluative framework for thinking about and talking about the past. The results suggest that, with daughters, mothers focus more on positive emotions and tend not to attribute negative emotions to the child. With sons, positive and negative emotions are discussed equally. Moreover, mothers never discuss anger with their daughters but they do with their sons. Finally, mother-daughter conversations emphasize the emotional state itself, whereas mother-son conversations often discuss the causes and consequences of emotions. The way in which these patterns might contribute to children's developing understanding of gender-appropriate emotional reactions are discussed.

Journal ArticleDOI
TL;DR: Point mutations have been associated with maternally inherited diseases, while deletions have been identified in some 'spontaneous' cases.

Journal ArticleDOI
TL;DR: Comparison of sequential virus isolates from macaque PBj for host range and the ability to be neutralized and of sequential serum samples for neutralization activity indicated that changes in biologic properties were detected in virus isolate and serum obtained at 6 months after infection and later.
Abstract: A virus pool isolated from lymphoid tissue of a macaque (PBj) infected for 14 months with SIV/SMM was found to be associated with acute disease and death. Six of six pig-tailed macaques, one of three rhesus macaques, and three of four SIV/SMM-seronegative mangabeys developed acute disease within 5 days and died from 7 to 13 days postinoculation; however, neither of two SIV/SMM-infected mangabeys died or developed disease. The virus associated with acute disease and death was shown by electron microscopy to be a lentivirus and was serologically indistinguishable from SIV/SMM by immunofluorescence and radioimmunoprecipitation assays. A biologic clone generated from lymphoid tissue of an animal that died 7 days after inoculation of the lethal pool resulted in death within 8 days of three of three pig-tailed macaques. Comparison of the lethal virus, designated SIV/SMM(PBj14), with the parent virus, SIV/SMM-9 (the isolate with which macaque PBj was originally inoculated), showed that although the kinetics of replication in peripheral blood mononuclear cells (PBMC) from pig-tailed macaques and mangabey monkeys were similar, SIV/SMM(PBj14) replicated more efficiently than SIV/SMM-9 in human PBMC and also replicated in chimpanzee PBMC whereas SIV/SMM and other SIV isolates did not. In addition, the variant was shown to replicate efficiently in some established cell lines whereas replication of SIV/SMM-9 in cell lines could be demonstrated only occasionally. That parental SIV/SMM-9, but not SIV/SMM(PBj14), was neutralized by serum from macaque PBj suggests that the variant may have been generated by immune selection. Comparison of sequential virus isolates from macaque PBj for host range and the ability to be neutralized and of sequential serum samples for neutralization activity indicated that changes in biologic properties were detected in virus isolates and serum obtained at 6 months after infection and later. Normal macaque PBMC infected in vitro with SIV/SMM(PBj14), but not with SIV/SMM-9 or other virus pools from PBj, formed syncytia with Sup-T1 cells, whereas all isolates formed syncytia with MOLT-4 clone 8 cells. These data suggest that, relative to SIV/SMM-9, SIV/SMM(PBj14) acquired multiple mutations, at least one (or more) of which is in the gene coding for the envelope glycoprotein. Continued analysis of this series of SIV/SMM isolates with diverse properties may lead to the identification of specific regions of the viral genome that influence defined biologic properties. Furthermore, the availability of a strain of SIV that induces rapid onset of disease and death may facilitate screening of drugs for antiviral activity against lentiviruses.