bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein Synthesis at Synaptic Sites on Dendrites
Authors: Steward Oswald , Schuman Erin M.
Published: July 2002

▪ Abstract  Studies over the past 20 years have revealed that gene expression in neurons is carried out by a distributed network of translational machinery. One component of this network is localized in dendrites, where polyribosomes and associated membranous elements are positioned beneath synapses and translate a particular population of dendritic mRNAs. The localization of translation machinery and mRNAs at synapses endows individual synapses with the capability to independently control synaptic strength through the local synthesis of proteins. The present review discusses recent studies linking synaptic plasticity to dendritic protein synthesis and mRNA trafficking and considers how these processes are regulated. We summarize recent information about how synaptic signaling is coupled to local translation and to the delivery of newly transcribed mRNAs to activated synaptic sites and how local translation may play a role in activity-dependent synaptic modification.
To Eat or to Sleep? Orexin in the Regulation of Feeding and Wakefulness
Authors: Willie Jon T. , Chemelli Richard M. , Sinton Christopher M. , Yanagisawa Masashi
Published: July 2002

▪ Abstract  Orexin-A and orexin-B are neuropeptides originally identified as endogenous ligands for two orphan G-protein–coupled receptors. Orexin neuropeptides (also known as hypocretins) are produced by a small group of neurons in the lateral hypothalamic and perifornical areas, a region classically implicated in the control of mammalian feeding behavior. Orexin neurons project throughout the central nervous system (CNS) to nuclei known to be important in the control of feeding, sleep-wakefulness, neuroendocrine homeostasis, and autonomic regulation. orexin mRNA expression is upregulated by fasting and insulin-induced hypoglycemia. C-fos expression in orexin neurons, an indicator of neuronal activation, is positively correlated with wakefulness and negatively correlated with rapid eye movement (REM) and non-REM sleep states. Intracerebroventricular administration of orexins has been shown to significantly increase food consumption, wakefulness, and locomotor activity in rodent models. Conversely, an orexin receptor antagonist inhibits food consumption. Targeted disruption of the orexin gene in mice produces a syndrome remarkably similar to human and canine narcolepsy, a sleep disorder characterized by excessive daytime sleepiness, cataplexy, and other pathological manifestations of the intrusion of REM sleep-related features into wakefulness. Furthermore, orexin knockout mice are hypophagic compared with weight and age-matched littermates, suggesting a role in modulating energy metabolism. These findings suggest that the orexin neuropeptide system plays a significant role in feeding and sleep-wakefulness regulation, possibly by coordinating the complex behavioral and physiologic responses of these complementary homeostatic functions.
Early Anterior/Posterior Patterning of the Midbrain and Cerebellum
Authors: Liu Aimin , Joyner Alexandra L
Published: July 2002

▪ Abstract  Transplantation studies performed in chicken embryos indicated that early anterior/posterior patterning of the vertebrate midbrain and cerebellum might be regulated by an organizing center at the junction between the midbrain and hindbrain. More than a decade of molecular and genetic studies have shown that such an organizer is indeed central to development of the midbrain and anterior hindbrain. Furthermore, a complicated molecular network that includes multiple positive and negative feedback loops underlies the establishment and refinement of a mid/hindbrain organizer, as well as the subsequent function of the organizer. In this review, we first introduce the expression patterns of the genes known to be involved in this patterning process and the quail-chick transplantation experiments that have provided the foundation for understanding the genetic pathways regulating mid/hindbrain patterning. Subsequently, we discuss the molecular genetic studies that have revealed the roles for many genes in normal early patterning of this region. Finally, some of the remaining questions and future directions are discussed.
α-Latrotoxin and Its Receptors: Neurexins and CIRL/Latrophilins
Authors: Südhof Thomas C
Published: July 2002

▪ Abstract  α-Latrotoxin, a potent neurotoxin from black widow spider venom, triggers synaptic vesicle exocytosis from presynaptic nerve terminals. α-Latrotoxin is a large protein toxin (120 kDa) that contains 22 ankyrin repeats. In stimulating exocytosis, α-latrotoxin binds to two distinct families of neuronal cell-surface receptors, neurexins and CLs (Cirl/latrophilins), which probably have a physiological function in synaptic cell adhesion. Binding of α-latrotoxin to these receptors does not in itself trigger exocytosis but serves to recruit the toxin to the synapse. Receptor-bound α-latrotoxin then inserts into the presynaptic plasma membrane to stimulate exocytosis by two distinct transmitter-specific mechanisms. Exocytosis of classical neurotransmitters (glutamate, GABA, acetylcholine) is induced in a calcium-independent manner by a direct intracellular action of α-latrotoxin, while exocytosis of catecholamines requires extracellular calcium. Elucidation of precisely how α-latrotoxin works is likely to provide major insight into how synaptic vesicle exocytosis is regulated, and how the release machineries of classical and catecholaminergic neurotransmitters differ.
RECENT PROGRESS IN BARYOGENESIS
Authors: Riotto Antonio , Trodden Mark
Published: July 2002

▪ Abstract  We provide an up-to-date account of progress toward understanding the origin of the observed baryon asymmetry of the universe. We provide a pedagogical introduction to the primary areas of research in this field, giving a detailed description of the different scenarios. The very recent developments in Grand-Unified-Theory baryogenesis, leptogenesis, electroweak baryogenesis, and the Affleck-Dine mechanism are presented. In particular, we focus on specific particle physics implementations, mostly in the context of supersymmetry, which lead to specific testable predictions.
THE CHOLESTEROL-RAISING FACTOR FROM COFFEE BEANS
Authors: Urgert R. , Katan M. B.
Published: July 2002

▪ Abstract  Some coffee brewing techniques raise the serum concentration of total and low-density-lipoprotein cholesterol in humans, whereas others do not. The responsible factors are the diterpene lipids cafestol and kahweol, which make up about 1% (wt:wt) of coffee beans. Diterpenes are extracted by hot water but are retained by a paper filter. This explains why filtered coffee does not affect cholesterol, whereas Scandinavian “boiled,” cafetiere, and Turkish coffees do. We describe the identification of the cholesterol-raising factors, their effects on blood levels of lipids and liver function enzymes, and their impact on public health, based on papers published up to December 1996.
Regulation of Metabolism and Body Fat Mass by Leptin
Authors: Baile Clifton A. , Della-Fera Mary Anne , Martin Roy J.
Published: July 2002

The relative stability of body weight over the long term and under a variety of environmental conditions that alter short-term energy intake and expenditure provides strong evidence for the regulation of body energy content. The lipostatic theory of energy balance regulation proposed 40 years ago that circulating factors, generated in proportion to body fat stores, acted as signals to the brain, eliciting changes in energy intake and expenditure. The discovery of leptin and its receptors has now provided a molecular basis for this theory. Leptin functions as much more than an adipocyte-derived signal of lipid stores, however. Although suppression of food intake is an important centrally mediated effect of leptin, considerable evidence indicates that leptin also functions both directly and indirectly, via the brain, to orchestrate complex metabolic changes in a number of organs and tissues, altering nutrient flux to favor energy expenditure over energy storage.
FAT METABOLISM IN INSECTS
Authors: Canavoso Lilián E , Jouni Zeina E , Karnas K Joy , Pennington James E , Wells Michael A
Published: July 2002

▪ Abstract  The study of fat metabolism in insects has received considerable attention over the years. Although by no means complete, there is a growing body of information about dietary lipid requirements, and the absolute requirement for sterol is of particular note. In this review we (a) summarize the state of understanding of the dietary requirements for the major lipids and (b) describe in detail the insect lipid transport system. Insects digest and absorb lipids similarly to vertebrates, but with some important differences. The hallmark of fat metabolism in insects centers on the lipid transport system. The major lipid transported is diacylglycerol, and it is carried by a high-density lipoprotein called lipophorin. Lipophorin is a reusable shuttle that picks up lipid from the gut and delivers it to tissues for storage or utilization without using the endocytic processes common to vertebrate cells. The mechanisms by which this occurs are not completely understood and offer fruitful areas for future research.
GASTROINTESTINALNEMATODES, NUTRITION ANDIMMUNITY: Breaking the Negative Spiral
Authors: Koski Kristine G , Scott Marilyn E
Published: July 2002

▪ Abstract  Nutritionists have long understood that intestinal nematode parasites have deleterious effects on host nutritional status, but only recently has the importance of malnutrition as a predisposing factor to intestinal nematodes been recognized. Here we review experimental and field studies on the effects of protein, energy, zinc, vitamin A, and iron deficiencies on gastrointestinal (GI) nematodes of humans, livestock, and laboratory rodents, and draw certain conclusions about the state of our current understanding. In general, malnutrition promotes the establishment, survival, and fecundity of these parasites, but the magnitude of the effect depends on factors such as host species, parasite species, particular infection protocol used, magnitude of the infection, severity of the nutritional deficiency, and presence of single or multiple infections and single or multiple nutritional deficiencies. We highlight the Th2 arm of the immune system as a component of primary importance in the association between malnutrition and GI nematode infections. We summarize what is known about underlying mechanisms that may account for the observed patterns. Finally, we suggest future research directions.
INHIBITION OF CARCINOGENESIS BY DIETARY POLYPHENOLIC COMPOUNDS
Authors: Yang Chung S , Landau Janelle M , Huang Mou-Tuan , Newmark Harold L
Published: July 2002

▪ Abstract  Plants consumed by humans contain thousands of phenolic compounds. The effects of dietary polyphenols are of great current interest due to their antioxidative and possible anticarcinogenic activities. A popular belief is that dietary polyphenols are anticarcinogens because they are antioxidants, but direct evidence for this supposition is lacking. This chapter reviews the inhibition of tumorigenesis by phenolic acids and derivatives, tea and catechins, isoflavones and soy preparations, quercetin and other flavonoids, resveratrol, and lignans as well as the mechanisms involved based on studies in vivo and in vitro. Polyphenols may inhibit carcinogenesis by affecting the molecular events in the initiation, promotion, and progression stages. Isoflavones and lignans may influence tumor formation by affecting estrogen-related activities. The bioavailability of the dietary polyphenols is discussed extensively, because the tissue levels of the effective compounds determine the biological activity. Understanding the bioavailability and blood and tissue levels of polyphenols is also important in extrapolating results from studies in cell lines to animal models and humans. Epidemiological studies concerning polyphenol consumption and human cancer risk suggest the protective effects of certain food items and polyphenols, but more studies are needed for clear-cut conclusions. Perspectives on the application of dietary polyphenols for the prevention of human cancer and possible concerns on the consumption of excessive amounts of polyphenols are discussed.
GLUTATHIONE-DEPENDENT BIOACTIVATION OF HALOALKENES
Authors: Anders M. W. , Dekant W.
Published: July 2002

▪ Abstract  Several halogenated alkenes are nephrotoxic in rodents. A mechanism for the organ-specific toxicity of these compounds to the kidney has been elucidated. The mechanism involves hepatic glutathione conjugation to dihaloalkenyl or 1,1-difluoroalkyl glutathione S-conjugates, which are cleaved by γ-glutamyltransferase and dipeptidases to cysteine S-conjugates. Haloalkene-derived cysteine S-conjugates may have four fates in the organism: (a) They may be substrates for renal cysteine conjugate β-lyases, which cleave them to form reactive intermediates identified as thioketenes (chloroalkene-derived S-conjugates), thionoacyl halides (fluoroalkene-derived S-conjugates not containing bromide), thiiranes, and thiolactones (fluoroalkene-derived S-conjugates containing bromine); (b) cysteine S-conjugates may be N-acetylated to excretable mercapturic acids; (c) they may undergo transamination or oxidation to the corresponding 3-mercaptopyruvic acid S-conjugate; (d) finally, oxidation of the sulfur atom in halovinyl cysteine S-conjugates and corresponding mercapturic acids forms Michael acceptors and may also represent a bioactivation reaction.

The formation of reactive intermediates by cysteine conjugate β-lyase may play a role in the target-organ toxicity and in the possible renal tumorigenicity of several chlorinated olefins widely used in many chemical processes.
INDUCTION OF CYTOCHROME P4501A1
Authors: Whitlock James P.
Published: July 2002

▪ Abstract  Cytochrome P4501A1 is a substrate-inducible microsomal enzyme that oxygenates polycyclic aromatic hydrocarbons, such as the carcinogen benzo(a)pyrene, as the initial step in their metabolic processing to water-soluble derivatives. Enzyme induction reflects increased transcription of the cognate CYP1A1 gene. The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin is the most potent known cytochrome P4501A1 inducer. Two regulatory proteins, the aromatic (aryl) hydrocarbon receptor (AhR) and the AhR nuclear translocator (Arnt), mediate induction. AhR and Arnt are prototypical members of the basic helix-loop-helix/Per-Arnt-Sim class of transcription factors. Mechanistic analyses of cytochrome P4501A1 induction provide insights into ligand-dependent mammalian gene expression, basic helix-loop-helix/Per-Arnt-Sim protein function, and dioxin action; such studies also impact public health issues concerned with molecular epidemiology, carcinogenesis, and risk assessment.
Pharmacokinetic/Pharmacodynamic Modeling in Drug Development
Authors: Sheiner L. B. , Steimer J.-L.
Published: July 2002

We propose a framework for considering the role of pharmacokinetic/ pharmacodynamic modeling in drug development and an appraisal of its current and potential impact on that activity. After some introduction, definitions, and background information on drug development, we discuss subject-matter models that underlie pharmacokinetic/pharmacodynamic modeling and show how they determine appropriate statistical models. We discuss the broad role modeling can play in drug development, enhancing primarily the “learning” steps, i.e. acquiring the information needed for the label and for planning efficient confirmatory clinical trials. Examples of past applications of modeling to drug development are presented in tabular form, followed by a discussion of some practical issues in application. Modeling will not reach its potential utility until it is manifest as a visible and separate work unit within a drug development program. We suggest that that work unit is the “in numero” study: a protocol-driven exercise designed to extract additional information, and/or answer a specific drug-development question, through an integrated model-based (meta-) analysis of existent raw data, often pooled across separate (clinical) studies.
Inhibition of Carcinogenesis by Tea
Authors: Yang Chung S. , Maliakal Pius , Meng Xiaofeng
Published: July 2002

Tea has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have inhibitory activity against tumorigenesis. The bioavailability and biotransformation of tea polyphenols, however, are key factors limiting these activities in vivo. The inhibition of tumorigenesis by green or black tea preparations has been demonstrated in animal models on different organ sites such as skin, lung, oral cavity, esophagus, forestomach, stomach, small intestine, colon, pancreas, and mammary gland. Epidemiological studies, however, have not yielded clear conclusions concerning the protective effects of tea consumption against cancer formation in humans. The discrepancy between the results from humans and animal models could be due to 1) the much higher doses of tea used in animals in comparison to human consumption, 2) the differences in causative factors between the cancers in humans and animals, and 3) confounding factors limiting the power of epidemiological studies to detect an effect. It is possible that tea may be only effective against specific types of cancer caused by certain etiological factors. Many mechanisms have been proposed for the inhibition of carcinogenesis by tea, including the modulation of signal transduction pathways that leads to the inhibition of cell proliferation and transformation, induction of apoptosis of preneoplastic and neoplastic cells, as well as inhibition of tumor invasion and angiogenesis. These mechanisms need to be evaluated and verified in animal models or humans in order to gain more understanding on the effect of tea consumption on human cancer.
COX-2: A Target for Colon Cancer Prevention
Authors: Marnett Lawrence J. , DuBois Raymond N.
Published: July 2002

▪ Abstract  Disease prevention is one area that both public and governmental agencies strongly support owing to its potential for an improved lifestyle and a reduction in health care costs. In this review, we focus on the clinical development of one target for cancer prevention, the COX-2 enzyme. This provides an excellent example of how basic research in biochemistry and pharmacology can lead to translational studies and eventually to approval of a drug by the FDA for use as a chemopreventive agent in humans. It is hoped that, as the genome sequence is understood more clearly, other targets will emerge that will provide even more effective drugs for future cancer prevention.
THE CONSTRUCTION AND INTERPRETATION OF MCSCF WAVEFUNCTIONS
Authors: Schmidt Michael W. , Gordon Mark S.
Published: July 2002

▪ Abstract  The multiconfiguration self-consistent field (MCSCF) method offers the most general approach to the computation of chemical reactions and multiple electronic states. This review discusses the design of MCSCF wavefunctions for treating these problems and the interpretation of the resulting orbitals and configurations. In particular, localized orbitals are convenient both for selection of the appropriate active space and for understanding the computed results. The computational procedures for optimizing these wavefunctions and the techniques for recovery of dynamical correlation energy are reviewed.
NUCLEAR SPIN CONVERSION IN POLYATOMIC MOLECULES
Authors: Chapovsky P. L. , Hermans L. J. F.
Published: July 2002

▪ Abstract  Except for ortho- and para-H2, little is known about nuclear spin isomers (or spin modifications) of molecules. The main reason is the lack of practical enrichment techniques. Recently, a few enrichment methods were developed, which opened up new possibilities in the field. These methods are briefly reviewed. Substantial progress in the field has been made by the introduction of light-induced drift as a gas-phase separation tool. This is illustrated by extensive data on CH3F, which reveal that the gas-phase ortho-para conversion is governed by intramolecular mixing of the nuclear spin states. The role of direct ortho-para transitions is small. Various aspects of the conversion were investigated in detail: pressure and collision partner dependence, isotope effect, and temperature dependence. The most decisive information on the spin conversion mechanism is derived from the observation of level-crossing resonances in an electric field and the quantum Zeno effect induced by collisions.
THE MITOCHONDRIAL DEATH/LIFE REGULATOR IN APOPTOSIS AND NECROSIS
Authors: Kroemer Guido , Dallaporta Bruno , Resche-Rigon Michèle
Published: July 2002

▪ Abstract  Both physiological cell death (apoptosis) and, in some cases, accidental cell death (necrosis) involve a two-step process. At a first level, numerous physiological and some pathological stimuli trigger an increase in mitochondrial membrane permeability. The mitochondria release apoptogenic factors through the outer membrane and dissipate the electrochemical gradient of the inner membrane. Mitochondrial permeability transition (PT) involves a dynamic multiprotein complex formed in the contact site between the inner and outer mitochondrial membranes. The PT complex can function as a sensor for stress and damage, as well as for certain signals connected to receptors. Inhibition of PT by pharmacological intervention on mitochondrial structures or mitochondrial expression of the apoptosis-inhibitory oncoprotein Bcl-2 prevents cell death, suggesting that PT is a rate-limiting event of the death process. At a second level, the consequences of mitochondrial dysfunction (collapse of the mitochondrial inner transmembrane potential, uncoupling of the respiratory chain, hyperproduction of superoxide anions, disruption of mitochondrial biogenesis, outflow of matrix calcium and glutathione, and release of soluble intermembrane proteins) entails a bioenergetic catastrophe culminating in the disruption of plasma membrane integrity (necrosis) and/or the activation of specific apoptogenic proteases (caspases) by mitochondrial proteins that leak into the cytosol (cytochrome c, apoptosis-inducing factor) with secondary endonuclease activation (apoptosis). The relative rate of these two processes (bioenergetic catastrophe versus protease and endonuclease activation) determines whether a cell will undergo primary necrosis or apoptosis. The acquisition of the biochemical and ultrastructural features of apoptosis critically relies on the liberation of apoptogenic proteases or protease activators from mitochondria. The fact that mitochondrial events control cell death has major implications for the development of cytoprotective and cytotoxic drugs.
TIMING OF SYNAPTIC TRANSMISSION
Authors: Sabatini B. L. , Regehr W. G.
Published: July 2002

▪ Abstract  Many behaviors require rapid and precisely timed synaptic transmission. These include the determination of a sound's direction by detecting small interaural time differences and visual processing, which relies on synchronous activation of large populations of neurons. In addition, throughout the brain, concerted firing is required by Hebbian learning mechanisms, and local circuits are recruited rapidly by fast synaptic transmission. To achieve speed and precision, synapses must optimize the many steps between the firing of a presynaptic cell and the response of its postsynaptic targets. Until recently, the behavior of mammalian synapses at physiological temperatures was primarily extrapolated from studies at room temperature or from the properties of invertebrate synapses. Recent studies have revealed some of the specializations that make synapses fast and precise in the mammalian central nervous system at physiological temperatures.
CELLULAR MECHANISMS OF TASTE TRANSDUCTION
Authors: Herness M. Scott , Gilbertson Timothy A.
Published: July 2002

▪ Abstract  Taste receptor cells respond to gustatory stimuli using a complex arrangement of receptor molecules, signaling cascades, and ion channels. When stimulated, these cells produce action potentials that result in the release of neurotransmitter onto an afferent nerve fiber that in turn relays the identity and intensity of the gustatory stimuli to the brain. A variety of mechanisms are used in transducing the four primary tastes. Direct interaction of the stimuli with ion channels appears to be of particular importance in transducing stimuli reported as salty or sour, whereas the second messenger systems cyclic AMP and inositol trisphosphate are important in transducing bitter and sweet stimuli. In addition to the four basic tastes, specific mechanisms exist for the amino acid glutamate, which is sometimes termed the fifth primary taste, and for fatty acids, a so-called nonconventional taste stimulus. The emerging picture is that not only do individual taste qualities use more than one mechanism, but multiple pathways are available for individual tastants as well.
Intrarenal Dopamine: A Key Signal in the Interactive Regulation of Sodium Metabolism
Authors: Aperia Anita C.
Published: July 2002

▪ Abstract  The kidney regulates sodium metabolism with extraordinary precision and sensitivity. This is accomplished by an intricate interaction between signals from extrarenal and intrarenal sources and between anti-natriuretic and natriuretic factors. Dopamine, produced in renal proximal tubule cells, plays a central role in this interactive network. Natriuretic hormones that are released from extrarenal sources, such as atrial natriuretic peptide, mediate some of their effects via renal dopamine receptors. On the level of the tubules, dopamine acts by opposing the effects of anti-natriuretic factors, such as angiotensin II and α-adrenergic receptors. Sodium retention leads to an increase in renal dopamine tonus, and the natriuretic effects of dopamine are more prominent under this condition. Inhibition or down-regulation of dopamine receptors significantly attenuates the natriuretic response to salt loading. Renal dopamine is modulated by the supply of filtered L-DOPA and the metabolism of dopamine via catechol-O-methyldopamine. The importance of dopamine as a natriuretic hormone is reflected by its capacity to inhibit the majority of renal tubule sodium transporters. Notably, the activity of Na+,K+ATPase is inhibited in most tubule segments by dopamine. Recent studies have elucidated many of the signaling pathways for renal dopamine receptors. Novel principles for homologous and heterologous sensitization of dopamine receptors have been detected that may explain some of the interaction between dopamine and other first messengers that modulate renal tubule sodium transport. A broad understanding of the renal dopamine system has become increasingly important, since there is now strong evidence from both clinical and experimental studies that dysregulation of the renal dopamine system plays a role in many forms of multigenetic hypertension.
Molecular Pathogenesis of Lung Cancer
Authors: Zöchbauer-Müller Sabine , Gazdar Adi F. , Minna John D.
Published: July 2002

▪ Abstract  Lung cancer is the most common cause of cancer death in the United States, killing more than 156,000 people every year. In the past two decades, significant progress has been made in understanding the molecular and cellular pathogenesis of lung cancer. Abnormalities of proto-oncogenes, genetic and epigenetic changes of tumor suppressor genes, the role of angiogenesis in the multistage development of lung cancer, as well as detection of molecular abnormalities in preinvasive respiratory lesions, have recently come into focus. Efforts are ongoing to translate these findings into new clinical strategies for risk assessment, chemoprevention, early diagnosis, treatment selection, and prognosis and to provide new targets and methods of treatment for lung cancer patients. All these strategies should aid in reducing the number of newly diagnosed lung cancer cases and in increasing the survival and quality of life of patients with lung cancer.
BIOLOGY AND EPIDEMIOLOGY OF RICE VIRUSES
Authors: Hibino Hiroyuki
Published: July 2002

▪ Abstract  The 15 known viruses that occur in rice are rice black-streaked dwarf, rice bunchy stunt, rice dwarf, rice gall dwarf, rice giallume, rice grassy stunt, rice hoja blanca, rice necrosis mosaic, rice ragged stunt, rice stripe necrosis, rice stripe, rice transitory yellowing, rice tungro bacilliform, rice tungro spherical, and rice yellow mottle viruses. This paper describes their geographical distribution, relation to vectors, infection cycles, field dispersal, and development, and lists recorded outbreaks of the viruses. Many rice viruses have become serious problems since rice cultivation has been intensified. Double-cropping of rice using improved, photo-insensitive cultivars of short growth duration has significantly influenced the incidence of these viruses.
WHITE PINE BLISTER RUST CONTROL IN NORTH AMERICA:A Case History
Authors: Maloy Otis C.
Published: July 2002

▪ Abstract  White pine blister rust was introduced into North America at the turn of the twentieth century, threatening valuable white pine resources. Measures to eliminate, contain, or control this disease constitute the most extensive forest disease control effort in time, money, men, and materiel in the history of US forestry. The major thrust was protection of pine stands by eliminating currant and gooseberry (ribes) alternate hosts from within and around these stands. Failures with ribes eradication resulted in application of antibiotic fungicides without adequate testing. These failures, coupled with lower dependence on white pines and reduced need for a large reserve of men for fire fighting, led to sudden termination of the program in 1967. The chronology of events and interactions between agencies and personnel responsible for the program provide an interesting case history and, it is hoped, valuable lessons for the future.
Advances in Understanding Plant Viruses and Virus Diseases
Authors: Zaitlin Milton , Palukaitis Peter
Published: July 2002

▪ Abstract  Plant viruses have had an impact on the science of virology and on plant pathology ever since the virus concept was discovered with Tobacco mosaic virus at the end of the nineteenth century. In this review, we highlight those discoveries. We have divided plant virus research into a “Classical Discovery Period” from 1883–1951 in which the findings were very descriptive; an “Early Molecular Era” from 1952 to about 1983, in which information was developed that described further properties of the viruses, aided by the development of a number of salient techniques; and the “Recent Period” from 1983 to the present, when techniques have been developed to modify plant virus genomes, to detect nonstructural gene products, to determine the functions of viral gene products, and to transform plants to elicit novel forms of resistance to viral diseases. In this period, plant virology has played a significant role in formulating an understanding of the mechanisms of gene silencing and recombination, plasmodesmatal function, systemic acquired resistance, and in developing methods for pathogen detection. We also attempt to predict the direction plant virology will take in the future.
The Ecology and Biogeography of Microorganisms on Plant Surfaces
Authors: Andrews John H. , Harris Robin F.
Published: July 2002

The vast surface of the plant axis, stretching from root tips occasionally buried deeply in anoxic sediment, to apical meristems held far aloft, provides an extraordinarily diverse habitat for microorganisms. Each zone has to a greater or lesser extent its own cohort of microorganisms, in aggregate comprising representatives from all three primary domains of life—Bacteria, Archaea, and Eucarya. While the plant sets the stage for its microbial inhabitants, they, in turn, have established varied relationships with their large partner. These associations range from relatively inconsequential (transient epiphytic saprophytes) to substantial (epiphytic commensals, mutualistic symbionts, endophytes, or pathogens). Through recent technological breakthroughs, a much better perspective is beginning to emerge on the nature of these relationships, but still relatively little is known about the role of epiphytic microbial associations in the life of the plant.
REINVENTING GOVERNMENT
Authors: Thompson Frank J. , Riccucci Norma M.
Published: July 2002

▪ Abstract  This review offers a synthesis and critical assessment of the reinvention movement in the United States. Focusing on the work of David Osborne, the National Performance Review, and the Winter Commission, it describes the key themes that define this movement and then assesses them from two major perspectives. The first perspective probes whether reinvention ideology provides a plausible prescription for improving the efficiency and effectiveness of public agencies. The second focuses on the implications of reinvention for accountability and related democratic concerns. The degree to which reinvention ideas appear to be taking root at the various levels of the federal system also receives attention. The authors conclude that the reinvention movement should not be dismissed as the latest fad, but rather as the fount of several plausible hypotheses that should be tested further. They also suggest that the American political system will place major, although not necessarily insurmountable, barriers in the way of sustaining reinvention.
TERM LIMITS
Authors: Cain Bruce E. , Levin Marc A.
Published: July 2002

▪ Abstract  The literature on term limits has burgeoned in recent years. This paper looks at both the empirical and normative studies, exploring how the term-limit debate is confounded by both fact and value disagreements. We identify four schools of thought with respect to the desirability of term limits and conclude that, because people start from different normative perspectives, findings about term-limit effects can be interpreted in very different ways. Reviewing the literature on electoral impacts, we discovered that term limits have increased turnover most noticeably in the more professionalized legislatures. The length of term limitations and the types of legislatures that adopt them are critical explanatory variables. The implications for the internal workings of legislatures and the balance of power are less well documented by scholars, but there is a great deal of testimony from legislators and lobbyists that term limits have changed their operations in important ways.
CORPORATISM: The Past, Present, and Future of a Concept
Authors: Molina Oscar , Rhodes Martin
Published: July 2002

▪ Abstract  Following a period of almost obsessive academic attention in the 1980s, in the early 1990s the concept of corporatism fell from favor, as its explanatory powers appeared to wane and the Keynesian welfare systems under which it had flourished apparently fell into decline. In the late 1990s, a new interest in corporatism emerged, in line with new patterns of concertation and corporatist behavior in some unexpected places—countries in which the institutional basis for collaborative, bargained methods of policy making and conflict resolution seemed distinctly unpromising. We review the extensive literature on corporatism since the 1970s and consider its applicability in the contemporary period. We argue that an excessively structural-functionalist interpretation of corporatism led many wrongly to predict its demise as a form of policy making, and that an understanding of its persistence and new manifestations today must resurrect and strengthen some early, recently neglected insights into processes of political exchange.
TOWARD A NEW POLITICAL METHODOLOGY: Microfoundations and ART
Authors: Achen Christopher H.
Published: July 2002

▪ Abstract  The past two decades have brought revolutionary change to the field of political methodology. Steady gains in theoretical sophistication have combined with explosive increases in computing power to produce a profusion of new estimators for applied political researchers. Attendance at the annual Summer Meeting of the Methodology Section has multiplied many times, and section membership is among the largest in APSA. All these are signs of success. Yet there are warning signs, too. This paper attempts to critically summarize current developments in the young field of political methodology. It focuses on recent generalizations of dichotomous-dependent-variable estimators such as logit and probit, arguing that even our best new work needs a firmer connection to credible models of human behavior and deeper foundations in reliable empirical generalizations.
ENVIRONMENTAL PSYCHOLOGY 1989–1994
Authors: Sundstrom Eric , Bell Paul A. , Busby Paul L. , Asmus Cheryl
Published: July 2002

▪ Abstract  A review of research and theory on transactions between people and physical environments emphasizes new contributions to theory and empirical research published in major journals of environmental psychology, 1989–1994. Theories focused on arousal, load, stress, privacy-regulation, behavior settings, and transactional analysis; new theory increasingly incorporated situational and contextual variables. Empirical research emphasized field settings over the laboratory and employed increasingly diverse methods, populations, and cultures. Environmental design studies integrated scientific and applied goals through post-occupancy evaluation. New findings concerned features of residences, work places, hospitals, schools, prisons, and larger community environments. New studies also addressed environmental stressors (e.g. temperature, noise); effects of attitudes and behaviors on conservation, crime, pollution, and hazards; and issues for neighborhoods, public places, and natural environments. Directions for the future include integrated theory to guide research, more design experiments, and development of conventions for case studies.
PEER RELATIONSHIPS AND SOCIAL COMPETENCE DURING EARLY AND MIDDLE CHILDHOOD
Authors: Ladd Gary W.
Published: July 2002

▪ Abstract  This review demarcates major periods of empirical activity and accomplishment (i.e. “generations”) in research on children's peer relations and social competence during recent decades and identifies the investigative agendas that were dominant or ascendant during these periods. A sampling of studies that were conducted during the most recent generation of peer relations research is organized and reviewed in relation to two types of research objectives: (a) enduring agendas—aims from past research generations that have continued to serve as an impetus for empirical investigation during the 1990s—and (b) innovative agendas—newly emergent objectives that are predicated on novel conceptual issues or ongoing research controversies and deficiencies. This profile of continuity and change in investigators' research agendas provides a platform for delineating and analyzing recent empirical accomplishments in the field of peer relations research.
The Effects of Family and Community Violence on Children
Authors: Margolin Gayla , Gordis Elana B.
Published: July 2002

This review examines theoretical and empirical literature on children’s reactions to three types of violence—child maltreatment, community violence, and interparental violence. In addition to describing internalizing and externalizing problems associated with exposure to violence, this review identifies ways that violence can disrupt typical developmental trajectories through psychobiological effects, posttraumatic stress disorder (PTSD), cognitive consequences, and peer problems. Methodological challenges in this literature include high rates of co-occurrence among types of violence exposure, co-occurrence of violence with other serious life adversities, heterogeneity in the frequency, severity, age of onset, and chronicity of exposure, and difficulties in making causal inferences. A developmental psychopathology perspective focuses attention on how violence may have different effects at different ages and may compromise children’s abilities to face normal developmental challenges. Emphasis is placed on the variability of children’s reactions to violence, on outcomes that go beyond diagnosable disorders, and on variables that mediate and moderate children’s reactions to violence.
Statistical Graphics: Mapping the Pathways of Science
Authors: Wainer Howard , Velleman Paul F.
Published: July 2002

▪ Abstract  This chapter traces the evolution of statistical graphics starting with its departure from the common noun structure of Cartesian determinism, through William Playfair's revolutionary grammatical shift to graphs as proper nouns, and alights on the modern conception of graph as an active participant in the scientific process of discovery. The ubiquitous availability of data, software, and cheap, high-powered, computing when coupled with the broad acceptance of the ideas in Tukey's 1977 treatise on exploratory data analysis has yielded a fundamental change in the way that the role of statistical graphics is thought of within science—as a dynamic partner and guide to the future rather than as a static monument to the discoveries of the past. We commemorate and illustrate this development while pointing readers to the new tools available and providing some indications of their potential.
Adult Clinical Neuropsychology: Lessons from Studies of the Frontal Lobes
Authors: Stuss Donald T. , Levine Brian
Published: July 2002

▪ Abstract  Clinical neuropsychologists have adopted numerous (and sometimes conflicting) approaches to the assessment of brain-behavior relationships. We review the historical development of these approaches and we advocate an approach to clinical neuropsychology that is informed by recent findings from cognitive neuroscience. Clinical assessment of executive and emotional processes associated with the frontal lobes of the human brain has yet to incorporate the numerous experimental neuroscience findings on this topic. We review both standard and newer techniques for assessment of frontal lobe functions, including control operations involved in language, memory, attention, emotions, self-regulation, and social functioning. Clinical and experimental research has converged to indicate the fractionation of frontal subprocesses and the initial mapping of these subprocesses to discrete frontal regions. One anatomical distinction consistent in the literature is that between dorsal and ventral functions, which can be considered cognitive and affective, respectively. The frontal lobes, in particular the frontal poles, are involved in uniquely human capacities, including self-awareness and mental time travel.
Gene-Environment Interplay in Relation to Emotional and Behavioral Disturbance
Authors: Rutter Michael , Silberg Judy
Published: July 2002

▪ Abstract  The conceptual and methodological issues involved in the study of gene-environment correlations (rGE) and interactions (GxE) are discussed in historical context. Quantitative genetic findings are considered with respect to rGE and GxE in relation to emotional and behavioral disturbance. Key conceptual and substantive implications are outlined in relation to both genetic and environmental risk mediation, with a brief note on evolutionary considerations.
A Future for Epidemiology?
Authors: Schwartz S. , Susser E. , Susser M.
Published: July 2002

▪ Abstract  This paper considers ways of thinking about causes and prevention that could guide epidemiology beyond the present era. Discontent with modern epidemiology, in the face of its substantial achievements, is taken as a sign that the guiding principles of the discipline warrant reconsideration. To begin this task, current practices are placed within an historical perspective, in a review of the dominant ideas of successive eras in epidemiology. Then the premises and constraints of the present era of chronic disease epidemiology, with its risk factor paradigm, are specified. Finally, elements of a causal paradigm for an emerging era are proposed. This paradigm encourages thinking about causes at multiple levels of organization and within the historical context of both societies and individuals. The proposed approach aims to preserve and build on the contributions of past eras, as well as the present one.
Multilevel Analysis in Public Health Research
Authors: Diez-Roux Ana V.
Published: July 2002

▪ Abstract  Over the past few years there has been growing interest in considering factors defined at multiple levels in public health research. Multilevel analysis has emerged as one analytical strategy that may partly address this need, by allowing the simultaneous examination of group-level and individual-level factors. This paper reviews the rationale for using multilevel analysis in public health research, summarizes the statistical methodology, and highlights some of the research questions that have been addressed using these methods. The advantages and disadvantages of multi level analysis compared with standard methods are reviewed. The use of multilevel analysis raises theoretical and methodological issues related to the theoretical model being tested, the conceptual distinction between group and individual-level variables, the ability to differentiate “independent” effects, the reciprocal relationships between factors at different levels, and the increased complexity that these models imply. The potentialities and limitations of multilevel analysis, within the broader context of understanding the role of factors defined at multiple levels in shaping health outcomes, are discussed.
The Changing Nature of Rural Health Care
Authors: Ricketts Thomas C.
Published: July 2002

▪ Abstract  The rural health care system has changed dramatically over the past decade because of a general transformation of health care financing, the introduction of new technologies, and the clustering of health services into systems and networks. Despite these changes, resources for rural health systems remain relatively insufficient. Many rural communities continue to experience shortages of physicians, and the proportion of rural hospitals under financial stress is much greater than that of urban hospitals. The health care conditions of selected rural areas compare unfavorably with the rest of the nation. The market and governmental policies have attempted to address some of these disparities by encouraging network development and telemedicine and by changing the rules for Medicare payments to providers. The public health infrastructure in rural America is not well understood but is potentially the most fragile aspect of the rural health care continuum.
Hormesis: Implications for Public Policy Regarding Toxicants
Authors: Lave Lester B
Published: July 2002

▪ Abstract  Protecting workers and the public from toxic chemicals, particularly carcinogens, has been a principal goal of public policy. In the absence of knowing by what mechanism of action a toxicant harms people, regulatory toxicology assumes that even tiny doses can cause harm. Risk aversion has led to legislation and regulation that seek to ban toxic chemicals or lower exposure to trivial levels. Contradicting this policy, many studies show health benefits from low-level exposure to toxicants, including some carcinogens. This is known as hormesis. Thus, hormesis could lead to a fundamental change in the policy for regulating toxic substances. In particular, all toxicants that benefit health at low-level exposures should face similar change in regulations for low-dose exposure. The result would be the dissolving of the source of differences in policy for carcinogens and noncarcinogens at low doses. Two questions must be answered before hormesis can be incorporated into regulatory policy. (a) Are there sensitive individuals who would be harmed at doses that would help most people? (b) Is the hormetic effect toxicant specific or would exposure to just a few toxicants achieve the full benefit from hormesis?