Showing papers by "Stony Brook University published in 1992"
Harvard University1, University of Texas Health Science Center at Houston2, Stony Brook University3, University of Manitoba4, Washington University in St. Louis5, University of Arizona6, University of Missouri7, Université de Montréal8, Icahn School of Medicine at Mount Sinai9, Laval University10, Yeshiva University11
TL;DR: In patients with asymptomatic left ventricular dysfunction after myocardial infarction, long-term administration of captopril was associated with an improvement in survival and reduced morbidity and mortality due to major cardiovascular events.
Abstract: Background. Left ventricular dilatation and dysfunction after myocardial infarction are major predictors of death. In experimental and clinical studies, long-term therapy with the angiotensin-converting—enzyme inhibitor captopril attenuated ventricular dilatation and remodeling. We investigated whether captopril could reduce morbidity and mortality in patients with left ventricular dysfunction after a myocardial infarction. Methods. Within 3 to 16 days after myocardial infarction, 2231 patients with ejection fractions of 40 percent or less but without overt heart failure or symptoms of myocardial ischemia were randomly assigned to receive double-blind treatment with either placebo (1116 patients) or captopril (1115 patients) and were followed for an average of 42 months. Results. Mortality from all causes was significantly reduced in the captopril group (228 deaths, or 20 percent) as compared with the placebo group (275 deaths, or 25 percent); the reduction in risk was 19 percent (95 percent conf...
5,503 citations
TL;DR: This commentary comprises an update of their initial review of T. gondii and a presentation of the current approaches to diagnosing and managing toxoplasmic encephalitis in HIV-infected patients.
Abstract: Involvement of the central nervous system (CNS) is common in patients with advanced disease due to human immunodeficiency virus (HIV). Symptoms range from lethargy and apathy to coma, incoordination and ataxia to hemiparesis, loss of memory to severe dementia, and focal to major motor seizures. Involvement may be closely associated with HIV infection per se, as in the AIDS dementia complex, but is frequently caused by opportunistic pathogens such as Toxoplasma gondii and Cryptococcus neoformans or malignancies such as primary lymphoma of the CNS. The clinical presentations of attendant and direct CNS involvement are remarkably non-specific and overlapping, yet a correct diagnosis is critical to successful intervention. Toxoplasmic encephalitis is one of the most common and most treatable causes of AIDS-associated pathology of the CNS. A great deal has been learned in the last 10 years about its unique presentation in the HIV-infected patient with advanced disease. Drs. Benjamin J. Luft of the State University of New York at Stony Brook and Jack S. Remington of the Stanford University School of Medicine and Palo Alto Medical Foundation's Research Institute have studied T. gondii for many years and are two of the leading experts in the field. This commentary comprises an update of their initial review (J Infect Dis 1988;157:1-6) and a presentation of the current approaches to diagnosing and managing toxoplasmic encephalitis in HIV-infected patients.
1,247 citations
TL;DR: In this paper, the authors argue that such a stance cannot provide a persuasive account of economic institutions, and suggest a broader toundation based on classical sociological arguments about the embeddedness of economic goals and activities in socially oriented goals and structures.
Abstract: Institutional economics has moved from a position, earlier in the twentieth century, of drawing eclectically on several other disciplines, to a stance of building its arguments almost entirely out of neoclassical materials This paper argues that such a stance cannot provide a persuasive account of economic institutions, and suggests a broader toundation based on classical sociological arguments about the embeddedness of economic goals and activities in socially oriented goals and structures Emphasis is placed on how economic activity comes to be coordinated by groups of people rather than carried out by isolated individuals Firms in developing countries, busmess groups, and the origins of the electrical utility industry in the United States are posed as cases of the 'social construction of economic institutions' It is argued that, although proper analysis of such cases involves a high level of contingency. these contingencies can be taken into account in a systematic theoretical argument, and that histori...
1,006 citations
TL;DR: The detection of 99.4% of Salmonella strains tested and the failure to specifically amplify DNA from non-Salmonellastrains confirm that the invA gene contains sequences unique to Salmoneella and demonstrate that this gene is a suitable PCR target, with potential diagnostic applications.
967 citations
TL;DR: The ability to establish a latent infection which can later be rescued appears to be a mechanism for ensuring the survival of AAV in the absence of a helper virus.
Abstract: Adeno-associated virus (AAV) is a human virus that can be propagated either as an integrated provirus or by lytic infection (Atchison et al. 1965; Hoggan et al. 1966, 1972). The ability to form a latent infection appears to be an integral part of the AAV life cycle. Except under special circumstances (Yacobson et al. 1987; Schlehofer et al. 1986; Yalkinoglu et al. 1988), AAV requires the presence of a helper virus to initiate a productive viral infection (Fig. 1). Members of either the herpes or adenovirus families can provide the necessary helper functions (Atchison et al. 1965; Melnick et al. 1965; Hoggan et al. 1966; Buller et al. 1981; McPherson et al. 1985) and vaccinia virus can provide at least partial helper function (Schlehofer et al. 1986). In the absence of a helper virus AAV produces no progeny virus, but instead integrates into a host chromosome (Hoggan et al. 1972; Berns et al. 1975; Handa et al. 1977; Cheung et al. 1980). With rare exceptions, AAV proviruses appear to be stable. However, if a cell line that is carrying an AAV provirus (Fig. 1) is subsequently superinfected with a helper virus, the AAV genome is excised and proceeds through a normal productive infection (Hoggan et al. 1972; Cheung et al. 1980). This ability to establish a latent infection which can later be rescued appears to be a mechanism for ensuring the survival of AAV in the absence of a helper virus. The unusual life cycle of AAV has led a number of parvovirus laboratories to explore the possibility of using AAV as a general mammalian transduction vector.
926 citations
TL;DR: The effects of competition were weakly density-dependent in cases in which it was possible to examine the effects of the density of neighbors, and competitive effects did not depend on the size attained in the absence of competitors.
Abstract: A meta-analysis was conducted on field-competition experiments published in six journals over a 10-yr period. We analyzed the effects of competition on the biomass of organisms belonging to 93 species in a wide variety of habitats. Competition had a large effect overall, with a great deal of heterogeneity in that effect among organisms. There were large differences among trophic levels in competitive effects, but the relative magnitude of competition at different trophic levels was contrary to the predictions of ecological theory. Primary producers and carnivores displayed small to medium effects. In these two groups, interspecific effects did not differ from intraspecific effects, nor did effects differ in terrestrial versus aquatic habitats. The effects of competition on herbivores ranged from large effects on anurans and lotic arthropods, to medium effects on marine mollusks and echinoderms, to effects that were not statistically distinguishable from zero for terrestrial arthropods. Interspecific compe...
815 citations
TL;DR: The multipartite nature of a chromosomal replication origin and the role of transcriptional activators in its function present a striking similarity to the organization of eukaryotic promoters.
Abstract: Although it has been demonstrated that discrete origins of DNA replication exist in eukaryotic cellular chromosomes, the detailed organization of a eukaryotic cellular origin remains to be determined. Linker substitution mutations were constructed across the entire Saccharomyces cerevisiae chromosomal origin, ARS1. Functional studies of these mutants revealed one essential element (A), which includes a match to the ARS consensus sequence, and three additional elements (B1, B2, and B3), which collectively are also essential for origin function. These four elements arranged exactly as in ARS1, but surrounded by completely unrelated sequence, functioned as an efficient origin. Element B3 is the binding site for the transcription factor-origin binding protein ABF1. Other transcription factor binding sites substitute for the B3 element and a trans-acting transcriptional activation domain is required. The multipartite nature of a chromosomal replication origin and the role of transcriptional activators in its function present a striking similarity to the organization of eukaryotic promoters.
624 citations
TL;DR: In this paper, negative thermal ionization mass spectrometry was used to analyze the boron isotopic compositions of modern marine carbonates with a 2σ reproducibility of standards and samples better than 0.7%.
576 citations
TL;DR: In this paper, the adiabatic single-crystal elastic stiffness coefficients of silicon dioxide (SiO 2 ) in the α-cristobalite structure were determined using laser Brillouin spectroscopy.
Abstract: Laser Brillouin spectroscopy was used to determine the adiabatic single-crystal elastic stiffness coefficients of silicon dioxide (SiO 2 ) in the α-cristobalite structure. This SiO 2 polymorph, unlike other silicas and silicates, exhibits a negative Poisson9s ratio; α-cristobalite contracts laterally when compressed and expands laterally when stretched. Tensorial analysis of the elastic coefficients shows that Poisson9s ratio reaches a maximum value of –0.5 in some directions, whereas averaged values for the single-phased aggregate yield a Poisson9s ratio of –0.16.
432 citations
TL;DR: An improved version of nonrelativistic QCD is constructed for use in lattice simulations of heavy-quark physics, and power-counting rules to assess the importance of the various operators in the action and compute all leading-order corrections required by relativity and finite lattice spacing are developed.
Abstract: We construct an improved version of nonrelativistic QCD for use in lattice simulations of heavy-quark physics, with the goal of reducing systematic errors from all sources to below 10%. We develop power-counting rules to assess the importance of the various operators in the action and compute all leading-order corrections required by relativity and finite lattice spacing. We discuss radiative corrections to tree-level coupling constants, presenting a procedure that effectively resums the largest such corrections to all orders in perturbation theory. Finally, we comment on the size of nonperturbative contributions to the coupling constants.
410 citations
TL;DR: It is proposed that chronic cocaine use can also cause clinically silent brain dysfunction, and this work aims to clarify the role of cocaine use in this condition.
Abstract: Neurological complications from cocaine use are well recognized. We propose that chronic cocaine use can also cause clinically silent brain dysfunction. We investigated brain glucose metabolism with positron emission tomography (PET) and 2-deoxy-2[18F] fluoro-D-glucose (FDG) in 21 neurologically intact chronic cocaine abusers (C) and 18 normal controls (N). The cocaine abusers were tested 1-6 weeks after the last use of cocaine and seven were retested after a 3 month drug-free period. Global cerebral glucose metabolism was not significantly different between controls and cocaine abusers (N = 38.4 +/- 3, C = 36.5 +/- 5 mumol/100 g of tissue, min). However, cocaine abusers had significantly (P less than 0.05) lower metabolic activity in 16 of the 21 left frontal regions and 8 of the 21 right frontal regions. These decreases persisted after 3-4 months of detoxification and were correlated with the dose (P less than or equal to 0.01) and the years of cocaine use (P less than or equal to 0.05). This study shows reduced rates of frontal metabolism in neurologically intact cocaine abusers that persist even after 3-4 months of detoxification.
TL;DR: In this article, the authors presented the data for a redshift survey of galaxies selected from the database of the Infrared Astronomical Satellite (IRAS), which consists of 5014 objects, of which 2658 are galaxies.
Abstract: We present the data for a redshift survey of galaxies selected from the database of the Infrared Astronomical Satellite (IRAS). The sample is flux limited to 1.936 Jy at 60 microns and covers 11.01 sr of the sky. It consists of 5014 objects, of which 2658 are galaxies. The remaining 2356 sources are listed in a separate table with identifications. Redshift data are also given for 212 IRAS galaxies which are not part of the complete sample, but were measured in conjunction with this project.
TL;DR: In this paper, a chiral ester enolate-imine condensation giving 3-hydroxy-4-aryl-β-lactams with excellent enantiomeric purity is successfully applied to the asymmetric synthesis of the enantiomersically pure taxol C-13 side chain, N-benzoyl-(2R,3S)-3-phenyl-isoserine and its analogs.
01 Dec 1992
TL;DR: It is concluded that postsynaptic dopamine receptor availability decreases with chronic cocaine abuse but may recover after a drug-free interval.
TL;DR: The physics of high-energy imaging is reviewed and the operation principles of the electronic portal imaging devices that are under development or are beginning to be used clinically are described.
Abstract: On-line electronic portal imaging devices are beginning to come into clinical service in support of radiotherapy. A variety of technologies are being explored to provide real-time or near real-time images of patient anatomy within x-ray fields during treatment on linear accelerators. The availability of these devices makes it feasible to verify treatment portals with much greater frequency and clarity than with film. This article reviews the physics of high-energy imaging and describes the operation principles of the electronic portal imaging devices that are under development or are beginning to be used clinically.
TL;DR: This paper found that only 12% of the women in this sample blamed themselves for causing their partner's violence and neither self-blame nor partner blame was associated with length of abuse or the frequency and severity of physical aggression.
Abstract: Thirty three currently battered women who sought counseling/support services from a Nassau County, New York community agency that provides services to victims of domestic violence participated. Eighty-nine percent of the women experienced severe acts of physical abuse and 31% of the women required surgery or suffered concussions as a result of their injuries. Fifty-two percent of the women scored above 20 on the Beck Depression Inventory. As the number, form, and consequences of physically aggressive acts increased and/or worsened, the women's depressive symptoms increased and self-esteem decreased. However, only 12% of the women in this sample blamed themselves for causing their partner's violence. Further, neither self-blame nor partner blame was associated with length of abuse or the frequency and severity of physical aggression. However, self-blame was marginally associated with depressive symptomatology.
TL;DR: In this article, the authors consider a non-cooperative game where the patentee acts as a Stackelberg leader selecting a licensing strategy by taking into account the reaction and competitive interaction of the firms.
TL;DR: It is proposed that cell-specific RE1-binding proteins are responsible, at least in part, for restricting expression of the type II sodium channel gene to specific neurons in the vertebrate nervous system.
TL;DR: The number of antidumping petitions initiated has increased dramatically in recent years as discussed by the authors, but only one-third of the antidumping cases actually result in dumping duties being levied, while nearly half of the cases are withdrawn or are voluntarily terminated.
TL;DR: In this article, the authors present the first systematic and controlled experimental data on the effect of post-hominid scavenging by hyaenas on skeletal element survival at archaeological and palaeontological sites.
TL;DR: In this article, a resummed perturbative expansion is used to obtain the self-energy in the high-temperature field-theory model up to order {ital g}{sup 2}{phi}{sup 4}.
Abstract: A resummed perturbative expansion is used to obtain the self-energy in the high-temperature {ital g}{sup 2}{phi}{sup 4} field-theory model up to order {ital g}{sup 4}. From this the zero-momentum pole of the effective propagator is evaluated to determine the induced thermal mass and damping rate for the bosons in the plasma to order {ital g}{sup 3}. The calculations are performed in the imaginary-time formalism and a simple diagrammatic analysis is used to identify the relevant diagrams at each order. Results are compared with similar real-time calculations found in the literature.
TL;DR: Data suggest that a physical signal that is clearly osteogenic in the young adult skeleton is hardly acknowledged in older bone tissue, which represents a deterioration of the bone cell population's ability to perceive these physical signals or a failure of their capacity to respond.
Abstract: The ability of physical stimuli demonstrated as potently osteogenic in the young adult skeleton were evaluated for their capacity to stimulate new bone formation in the aging skeleton. Using the externally loadable, functionally isolated turkey ulna preparation, the ulnae of 1-year-old (n=5), and 3-year-old (n=3) turkeys were subjected to 300 cycles per day of a load regimen generating a high but physiologic level of normal strain (3,000 microstrain). Following 8 weeks of loading, areal properties and histomorphometry were performed on both the experimental and intact control ulnae. Bone cross-sectional areas in the 1-year-old animal increased by 30.2% (±7.8%) as compared with the intact contralateral control ulnae, whereas the areal properties of the older skeleton remained essentially unchanged (-3.3±7.5%). Renewed bone formation in the experimental ulnae of the 1-year-old animals was characterized by the activation of periosteal bone apposition (4.0±0.4 μm/day). In comparison, periosteal bone formation in the 3-year-old males was activated in only 1 animal, and this at a significantly attenuated level (less than 0.8 μm/day). The histomorphometric evaluation of intracortical bone remodeling revealed no significant differences between the control and experimental ulnae in either age group. However, osteon mean wall thickness and bone formation sigma were significantly increased in the 3-year-old males (P<0.05). In conclusion, these data suggest that a physical signal that is clearly osteogenic in the young adult skeleton is hardly acknowledged in older bone tissue. Whether this represents a deterioration of the bone cell population's ability to perceive these physical signals or a failure of their capacity to respond is not yet clear.
TL;DR: This article explored readers' mental models of described scenes and found that reaction times to identify objects were fastest for the head/feet (above/below) axis, then the front/back (front/behind) axis and then the left/right axis, conforming to the spatial framework analysis which reflects people's conceptions of space based on typical interactions in space.
TL;DR: A new model describing strongly correlated electrons on a general {ital d}-dimensional lattice is presented, an extended Hubbard model that contains the {ital t}-{ital J} model as a special case and it is exactly solvable by Bethe ansatz.
Abstract: We present a new model describing strongly correlated electrons on a general {ital d}-dimensional lattice. It is an extended Hubbard model and it contains the {ital t}-{ital J} model as a special case. The model naturally describes local electron pairs, which can move coherently at arbitrary momentum. By using an {eta}-pairing mechanism we can construct eigenstates of the Hamiltonian with off-diagonal long-range order. In the attractive case the exact ground state is superconducting in any number of dimensions. On a one-dimensional lattice, the model is exactly solvable by Bethe ansatz.
TL;DR: Prolog, with its depth-first backtracking search through the tree of SLD refutations, is a procedural implementation of the declarative Horn clause language, which can benefit from the kinds of optimization techniques developed for traditional procedural languages.
Abstract: Interpretation Next we turn to another general area of recent active research in logic programming: abstract interpretation. In the area of declarative languages, the issue of optimization is of prime importance. The most successful example of the implementation of a declarative language is the relational database query language, Structured Query Language (SQL). This is the standard language used to interact with relational databases. It is critically important for the SQL compiler to produce a near optimal way to evaluate whatever query it is given. It is only because such optimization is possible that users are willing to use SQL. For general Horn clause programs, which include recursive definitions and recursive data structures, a comparable global optimization cannot yet (and may never) be achieved. Prolog, with its depth-first backtracking search through the tree of SLD refutations, is a procedural implementation of the declarative Horn clause language. And, as a procedural programming language, it can benefit f rom the kinds o f optimization techniques developed for traditional procedural languages. To perform certain optimizations, the compiler must know certain properties of any execution of the program being processed. For example, any Prolog predicate might be called with any arbitrary set of its parameters given ground values. This multidirectionality is one source of Prolog's power. However, many Prolog predicates are called in only one direction (i.e., in one mode). I f the Prolog compiler knows the mode of a call, it can often use that information to generate more efficient code. Such information depends on global properties of the program and query. One way to gain such information would be to execute, at compile time, the program for all inputs, and then use the information obtained. This direct approach is, of course, infeasible in practice. Any interesting program will have infinitely many computations. Therefore, rather than execute the program at compile time, we \"generalize\" the program to make a new approximate program. The approximate program preserves the structure of the original program but operates on abstract objects (perhaps representing sets of objects) rather than the concrete objects. Then the abstract program is executed to provide approximate information about all the executions of the original program. This process is called abstract interpretation. One simple example of abstract interpretation that is familiar to everyone is the rule o f signs. Consider a program in a very simple programming language that allows a sequence of assignments, each of which assigns to a variable an expression of plus, minus and times over integers and variables. Consider, for example, the program of Figure 12. Given a set of integer values for the input variables, X and Y, executing this program will generate integer values for the output variables: U, V, W and Z. For example, initializing X = 5 and Y = 6 , the program computes Z = 3 0 , W = 900, U = 9 3 0 , and V = 870. We can extract some information that relates the inputs and outputs of the program by using the rule of signs. We abstract the integers into three sets: 1) negative integers ( ) , 2) zero (0), and 3) positive integers (+). We also denote the whole set of integers by (all). We know how the operators of plus, minus and times operate on these sets o f integers. For example, the product of two positive integers is a positive integer. The abstracted table for times
TL;DR: The formulation of the model in terms of the QISM enables us to derive explicit expressions for higher conservation laws.
Abstract: We construct the enveloping fundamental spin model of the [ital t]-[ital J] Hamiltonian using the quantum-inverse-scattering method (QISM), and present all three possible algebraic Bethe [ital Ansa]$[ital iuml]---[ital tze]. Two of the solutions have been previously obtained in the framework of the coordinate-space Bethe [ital Ansatz] by Sutherland and by Schlottmann and Lai, whereas the third solution is new. The formulation of the model in terms of the QISM enables us to derive explicit expressions for higher conservation laws.
TL;DR: Women in their third trimester of pregnancy demonstrated polysomnographic patterns of sleep maintenance insomnia and the most frequent sleep complaints in the pregnant group were restless sleep, low back pain, leg cramps and frightening dreams.
Abstract: Twelve women in their third trimester of pregnancy and 10 age-matched nonpregnant controls underwent complete polysomnography for one night in the laboratory. Seven of the original women returned for a second study 3-5 months postpartum. During late pregnancy, women showed increased wake after sleep onset (WASO) and a lower sleep efficiency in comparison with the control group. The percentage of rapid eye movement (REM) sleep was significantly decreased and the percentage of stage 1 significantly increased compared to the nonpregnant group. At 3-5 months postpartum, a significant reduction in WASO and increased sleep efficiency were noted. However, only a slight increase was noted in REM sleep during the postpartum period compared to the prepartum period. The most frequent sleep complaints in the pregnant group were restless sleep, low back pain, leg cramps and frightening dreams. In summary, in accordance with their complaints, women in their third trimester demonstrated polysomnographic patterns of sleep maintenance insomnia.
TL;DR: In this paper, the interplay between the attractive and repulsive interactions which governs the size of the interacting contributions is discussed, and the causal behaviour of some of the conventional excluded-volume approaches is examined.
TL;DR: This result indicates that stimulation of the EGF receptor is involved in the invasion of cultured Henle-407 cells by S. typhimurium, and induces the tyrosine phosphorylation of the epidermal growth factor (EGF) receptor.
Abstract: SALMONELLA infection continues to be a major world-wide health problem1. One essential pathogenic feature common to all Salmonella is their ability to penetrate the cells of the intestinal epithelium which are normally non-phagocytic2. The internalization of Salmonella into mammalian cells is thought to be a receptor-mediated phenomenon and the invasion of cultured epithelial cells depends on several Salmonella genes, but nothing is known about the host determinants participating in this interaction3–6. Protein tyrosine phosphorylation follows stimulation of many cell-surface receptors to initiate signal transduction path-ways that stimulate cellular responses7. We report here that invasion of cultured Henle-407 cells by Salmonella typhimurium induces the tyrosine phosphorylation of the epidermal growth factor (EGF) receptor. In contrast, an isogenic strain of S. typhimurium that is defective in invasion owing to a mutation in the invA gene is unable to induce such phosphorylation. Addition of EGF to cultured Henle-407 cells allowed the internalization of the invasion-defective S. typhimurium invA mutant although it did not cause the internalization of an adherent, but non-invasive, strain of Escherichia coli. This result indicates that stimulation of the EGF receptor is involved in the invasion of cultured Henle-407 cells by S. typhimurium.