Showing papers by "University of California, Irvine published in 1989"
TL;DR: 'The following abbreviations have been used in the text'; I3-N-uxalyl-L-a,l3diaminu-prupiunic acid; ACPD, Trans-l-aminu-cydupentyl-I,3-dicarbuxylate; AMPA, a aminU-3-hydruxy-5-methyl-isoxazole-4-propionate; AP4, 2-
Abstract: 'The following abbreviations have been used in the text; I3-L-ODAP, I3-N-uxalyl-L-a,l3diaminu-prupiunic acid; ACPD, Trans-l-aminu-cydupentyl-I,3-dicarbuxylate; AMPA, a aminu-3-hydruxy-5-methyl-isoxazole-4-propionate; AP4, 2-amino-4-phosphonobutyrate; AP5, 2-amino-5-phuphonovalerate; ASP, aspartate; CNQX, 6-cyano-7-nitro-quinoxaline-2,3-dione; CPP, 3-(2-earboxypiperazin-4-yl)prupyl-l -phosphate; cyelo-Leu, eydo-Ieucine; DAA, D-a amino-adipate; DGG, y-D-glutamylglycine; DNQX, 6,7-dinitro-quinoxaline-2,3dione; EAA, excitatory amino acids; GABA, gamma-aminu-butyric acid; GDEE, glutamate diethyl ester; GLU, glutamate; GL Y, glycine; HA-966, 3-amino-l-hydroxypyrrolidone-2; lBO, ibotenate; IP, inositol phosphate; KA, kainate; KYN, kynurenate; MK-801, dibenzoeyclohepteneimine; NMDA, N-methyl-D-aspartate; PCP, phencyclidine; QA, quisqualate; SER, serine; SOP, serine O-phosphate; TCP, 1-[1-(2-thienyl)-eyclohexyIJpiperidine
2,226 citations
TL;DR: This article examined the multivariate effects of demographic characteristics on outcomes such as work attitudes and behavior, and found that individual demographic characteristics has typically examined only direct effects on outcomes, such as job attitudes and behaviour.
Abstract: Previous research on individual demographic characteristics has typically examined only direct effects on outcomes such as work attitudes and behavior. This investigation examined the multivariate ...
1,714 citations
TL;DR: A novel three-dimensional optical memory device is presented that allows fast random access of the information and extremely high bit densities and Absorption and emission data show that two-photon writing and reading of information is feasible.
Abstract: A novel three-dimensional (3-D) optical memory device is presented that allows fast random access of the information and extremely high bit densities. This device is based on two-photon writing, reading, and erasing of the information in a photochromic material embedded in a polymer matrix. Absorption and emission data show that two-photon writing and reading of information is feasible. The advantages and properties of such a 3-D optical memory are discussed.
1,540 citations
01 Dec 1989
TL;DR: The paper argues that the development of distributed artificial intelligence should be based on a social metaphor, rather than a psychological one, and the Turing Test should be replaced by the Durkheim Test, that is, systems should be tested with respect to their ability to meet community goals.
Abstract: The paper argues that the development of distributed artificial intelligence should be based on a social metaphor, rather than a psychological one. The Turing Test should be replaced by the “Durkheim Test,” that is, systems should be tested with respect to their ability to meet community goals. Understanding community goals means analyzing the problem of due process in open systems. Due process means incorporating differing viewpoints for decision-making in a fair and flexible manner. It is the analog of the frame problem in artificial intelligence. From analyses of organizational problem solving in scientific communities, the paper derives the concept of boundary objects, and suggests that this concept would be an appropriate data structure for distributed artificial intelligence. Boundary objects are those objects that are plastic enough to be adaptable across multiple viewpoints, yet maintain continuity of identity. Four types of boundary object are identified: repositories, ideal types, terrain with coincident boundaries, and forms.
1,406 citations
TL;DR: In this article, the effects of variable thermophysical properties, non-unitary Lewis number in the gas film, and effect of the Stefan flow on heat and mass transfer between the droplet and the gas, and the effect of internal circulation and transient liquid heating are investigated.
1,268 citations
Book•
01 Jan 1989TL;DR: The authors develop the structure of the set of stable matchings in the stable marriage problem in a more general and algebraic context than has been done previously; they discuss the problem's structure in terms of rings of sets, which allows many of the most useful features to be seen as features of a moregeneral set of problems.
Abstract: This book probes the stable marriage problem and its variants as a rich source of problems and ideas that illustrate both the design and analysis of efficient algorithms. It covers the most recent structural and algorithmic work on stable matching problems, simplifies and unifies many earlier proofs, strengthens several earlier results, and presents new results and more efficient algorithms.The authors develop the structure of the set of stable matchings in the stable marriage problem in a more general and algebraic context than has been done previously; they discuss the problem's structure in terms of rings of sets, which allows many of the most useful features to be seen as features of a more general set of problems. The relationship between the structure of the stable marriage problem and the more general stable roommates problem is demonstrated, revealing many commonalities.The results the authors obtain provide an algorithmic response to the practical, and political, problems created by the asymmetry inherent in the Gale Shapley solutions, leading to alternative methods and better compromises than are provided by the Gale Shapley method. And, in contrast to Donald Knuth's earlier work which primarily focused on the application of mathematics to the analysis of algorithms, this book illustrates the productive and almost inseparable relationship between mathematical insight and the design of efficient algorithms.Dan Gusfield is Associate Professor of Computer Science at the University of California, Davis. Robert W. Irving is Senior Lecturer in Computing Science at the University of Glasgow. The Stable Marriage Problem is included in the Foundations of Computing Series, edited by Michael Garey and Albert Meyer.
1,204 citations
TL;DR: This article found that a favorable opinion about the overseas assignment by the spouse is positively related to the spouse's adjustment and the novelty of the foreign culture has a negative relationship with the spouse adjustment.
1,065 citations
TL;DR: The preliminary results suggest that GA is a powerful means of reducing the time for finding near-optimal subsets of features from large sets.
848 citations
Book•
01 Jan 1989TL;DR: In this article, the authors studied prosocial behavior in the family, role taking, interpersonal prolem solving, and moral judgment and found that emotional factors played a role in prosocial behaviour.
Abstract: Preface 1. Introduction 2. Methodological and theoretical considerations in the study of prosocial behavior 3. Biology and prosocial behavior 4. Culture and prosocial behavior 5. 'Person' variables and prosocial behavior 6. Socialization in the family 7. Socialization by agents outside the family 8. Cognition, role taking, interpersonal prolem solving, and moral judgment 9. Emotional factors in prosocial behavior 10. Situational determinants 11. Conclusions References Name index Subject index.
630 citations
TL;DR: In situ hybridization and nuclease protection analyses demonstrate that limbic seizures dramatically increase the amount of messenger RNA for NGF in the neurons of the hippocampal dentate gyrus within 1 hour of seizure onset and in broadly distributed neocortical and olfactory forebrain neurons some hours later.
Abstract: Nerve growth factor (NGF) produced by telencephalic neurons provides critical trophic support for cholinergic neurons of the basal forebrain. In situ hybridization and nuclease protection analyses demonstrate that limbic seizures dramatically increase the amount of messenger RNA for NGF in the neurons of the hippocampal dentate gyrus within 1 hour of seizure onset and in broadly distributed neocortical and olfactory forebrain neurons some hours later. The increased messenger RNA species is indistinguishable from messenger RNA for transcript B of the beta subunit of NGF from mouse submandibular gland. Thus, the expression of a known growth factor is affected by unusual physiological activity, suggesting one route through which trophic interactions between neurons in adult brain can be modified.
629 citations
TL;DR: Kynurenate‐type compounds inhibit glycine binding and are suggested to form a novel class of antagonists of the NMDA receptor acting through the glycine site, suggesting the existence of a dual and opposite modulation of NMDA receptors by endogenous ligands.
Abstract: Membranes from rat telencephalon contain a single class of strychnine-insensitive glycine sites. That these sites are associated with N-methyl-D-aspartic acid (NMDA) receptors is indicated by the observations that [3H]glycine binding is selectively modulated by NMDA receptor ligands and, conversely, that several amino acids interacting with the glycine sites increase [3H]N-[1-(2-thienyl)cyclohexyl]piperidine ([3H]TCP) binding to the phencyclidine site of the NMDA receptor. The endogenous compound kynurenate and several related quinoline and quinoxaline derivatives inhibit glycine binding with affinities that are much higher than their affinities for glutamate binding sites. In contrast to glycine, kynurenate-type compounds inhibit [3H]TCP binding and thus are suggested to form a novel class of antagonists of the NMDA receptor acting through the glycine site. These results suggest the existence of a dual and opposite modulation of NMDA receptors by endogenous ligands.
TL;DR: It is concluded from this pilot study that insulin treatment with an implanted, variable-rate, programmable pump is feasible for periods up to two years.
Abstract: We undertook a trial to determine whether an implanted insulin-delivery system, the programmable implantable medication system (PIMS), could be used to treat patients with insulin-dependent diabetes. PIMS is a pulsatile, programmable pump with a battery life expectancy of five years. The reservoir is refilled transcutaneously every two months with a surfactant-stabilized human insulin preparation containing 400 U of insulin per milliliter. Eighteen patients received PIMS-delivered insulin for 4 to 25 months (mean, 18). The total PIMS-implantation experience comprised 28 patient-years. Good glycemic control was established and sustained during treatment (mean plasma glucose level, 7.3 mmol per liter; mean glycohemoglobin level, 8 percent [upper limit of normal, 7.5 percent]), with significantly reduced glycemic fluctuations. The total mean daily insulin dose did not change. Insulin solutions withdrawn from the pump reservoirs contained 92 percent native insulin and preserved biologic activity. There were no surgical or skin complications, severe hypoglycemic episodes, or instances of diabetic ketoacidosis. One pump was replaced because of a manufacturing defect, and four patients had catheter blockages due to omental-tissue encapsulation; two withdrew from the study and two had devices that were repaired successfully. The actuarial rate of survival of catheter function was 78 percent at 1.5 years. We conclude from this pilot study that insulin treatment with an implanted, variable-rate, programmable pump is feasible for periods up to two years.
TL;DR: A peptide ligand homologous to the first 28 residues of the beta-amyloid protein (beta 1-28) was tested in cultures of hippocampal pyramidal neurons for neurotrophic or neurotoxic effects and appeared to have neurotrophic activity.
Abstract: The beta-amyloid protein is progressively deposited in Alzheimer's disease as vascular amyloid and as the amyloid cores of neuritic plaques. Contrary to its metabolically inert appearance, this peptide may have biological activity. To evaluate this possibility, a peptide ligand homologous to the first 28 residues of the beta-amyloid protein (beta 1-28) was tested in cultures of hippocampal pyramidal neurons for neurotrophic or neurotoxic effects. The beta 1-28 appeared to have neurotrophic activity because it enhanced neuronal survival under the culture conditions examined. This finding may help elucidate the sequence of events leading to plaque formation and neuronal damage in Alzheimer's disease.
TL;DR: It is shown that immunoreactivity for calbindin-28 and for parvalbumin is localized in separate populations of inhibitory GABA interneurons in all areas of the neocortex of Old World monkeys.
Abstract: Calcium ions play a key role in many aspects of neuronal behavior and certain calcium binding proteins that may influence this behavior are differentially distributed in the central nervous system. In this study it is shown that immunoreactivity for calbindin-28 and for parvalbumin is localized in separate populations of inhibitory GABA interneurons in all areas of the neocortex of Old World monkeys. Virtually all GABA neurosn show immunoreactivity for one or other calcium binding protein but, except for a few cells in layer IV, GABA cells do not show immunoreactivity for both proteins. Among the two cell populations, parvalbumin immunoreactivity characterizes basket neurons while calbindin immunoreactivity characterizes double bouquet neurons. These findings suggest that the two GABA cell types differ in their regulation of calcium homeostasis and may yield clues to their different roles in intracortical circuitry.
Book•
01 Jan 1989TL;DR: The Architecture of Accountability, Privatization and Public Spending Evidence And Arguments as discussed by the authors, Organizational Form and Function, The Evidence On Efficiency, The Terms of the Privatisation Decision Cases And Cautionary Tales, Lessons from the Pentagon, Local Service Contracting, Private Prisons Debate, Business, Government, and Job Training
Abstract: The Stakes * The Architecture of Accountability * Privatization and Public Spending Evidence And Arguments * Organizational Form and Function * The Evidence On Efficiency * The Terms of the Privatization Decision Cases And Cautionary Tales * Lessons from the Pentagon * Local Service Contracting * The Private Prisons Debate * Business, Government, and Job Training Conclusions * The (Limited) Promise of Privatization
TL;DR: The zygomatic ligaments (McGregor's patch) anchor the skin of the cheek to the inferior border of the zygoma just posterior to the origin of the Zygomaticus minor muscle; the mandibular ligaments tether the overlying skin to the anterior mandible; these four ligaments are useful as anatomic landmarks during facial dissections.
Abstract: The zygomatic ligaments (McGregor's patch) anchor the skin of the cheek to the inferior border of the zygoma just posterior to the origin of the zygomaticus minor muscle. The mandibular ligaments tether the overlying skin to the anterior mandible. Both these ligaments are obstacles to surgical maneuvers intended to advance the overlying skin. They also restrain the facial skin against gravitational changes, and they delineate the anterior border of the "jowl" area. The platysma-auricular ligament is a thin fascial sheet that extends from the posterosuperior border of the platysma and that is intimately attached to the periauricular skin; it serves as a surgical guide to the posterosuperior border of the platysma. The anterior platysma-cutaneous ligaments are variable fascial condensations that anchor the SMAS and platysma to the dermis. They can cause anatomic disorientation with dissection of false planes into the dermis. These four ligaments are useful as anatomic landmarks during facial dissections. The tethering effects of the zygomatic and mandibular ligaments must be interrupted if a maximum upward movement of the facial skin is desired.
TL;DR: An interfacial hydrophobicity scale, IFH(h), with a variable hydrogen bond parameter (h), is introduced that permits one to consider explicitly hydrogen bonding in transbilayer helix searches.
Abstract: One method of obtaining useful information about the physical chemistry of peptide/bilayer interactions is to relate thermodynamic parameters of the interactions to structural parameters obtained by diffraction methods. We report here the results of the application of this approach to interactions of hydrophobic tripeptides of the form Ala-X-Ala-0-tert-butyl with lipid bilayers. The thermodynamic constants (ΔG_t> ΔH_1, and Δ1) for the transfer of the tripeptides from water into DMPC vesicles were determined for X = Leu, Phe, and Trp and found to be consistent with those expected for hydrophobic interactions
above the phase transition of DMPC. Combining these results with the earlier ones of Jacobs and White [(1986) Biochemistry 25, 2605-2612], the favorable free energies of transfer with different amino acids in the -X- position increase in the order Gly
TL;DR: Serial sections of human thalami stained for Nissl substance, myelin, cytochrome oxidase and acetylcholinesterase revealed a parcellation of the nuclei that could be correlated with that used in the macaque monkey thalamus, and human nuclei were re-named using the monkey nomenclature.
TL;DR: In this paper, the authors developed and analyzed models which include among citizens' payoffs "relational goods", objectives which depend upon interactions among persons, and provided a model of "mobilization" in terms of the preferences and decisions of a rational individual.
Abstract: Theoretical explanations of why rational individuals would participate in politics remain unsatisfactory. This paper addresses the problem by developing and analyzing models which include among citizens' payoffs “relational goods,” objectives which depend upon interactions among persons. The models predict more participation than do the standard approaches. For example, under some circumstances persons will be more likely to act if they believe others will act, contrary to free-rider logic. More importantly, conditions are identified under which leaders could increase mass activity. Thus, a model is provided of “mobilization” in terms of the preferences and decisions of a rational individual.
TL;DR: The regulation of extracellular proteolysis by PN-II and the deposition of at least parts of the molecule in senile plaques is consistent with previous reports that implicate altered proteolytic activity in the pathogenesis of Alzheimer's disease.
Abstract: Protease nexin-II (PN-II) is a protease inhibitor that forms SDS-resistant inhibitory complexes with the epidermal growth factor (EGF)-binding protein, the gamma-subunit of nerve growth factor, and trypsin. The properties of PN-II indicate that it has a role in the regulation of certain proteases in the extracellular environment. Here we describe more of the amino-acid sequence of PN-II and its identity to the deduced sequence of the amyloid beta-protein precursor (APP). Amyloid beta-protein is present in neuritic plaques and cerebrovascular deposits in individuals with Alzheimer's disease and Down's syndrome. A monoclonal antibody against PN-II (designated mAbP2-1) recognized PN-II in immunoblots of serum-free culture medium from human glioblastoma cells and neuroblastoma cells, as well as in homogenates of normal and Alzheimer's disease brains. In addition, mAbP2-1 stained neuritic plaques in Alzheimer's disease brain. PN-II was a potent inhibitor of chymotrypsin with an inhibition constant Ki of 6 x 10(-10)M. Together, these data demonstrate that PN-II and APP are probably the same protein. The regulation of extracellular proteolysis by PN-II and the deposition of at least parts of the molecule in senile plaques is consistent with previous reports that implicate altered proteolysis in the pathogenesis of Alzheimer's disease.
TL;DR: In this article, the authors give a new proof of exponential localization in the Anderson tight binding model which uses many ideas of the Frohlich, Martinelli, Scoppola and Spencer proof.
Abstract: We give a new proof of exponential localization in the Anderson tight binding model which uses many ideas of the Frohlich, Martinelli, Scoppola and Spencer proof, but is technically simpler-particularly the probabilistic estimates.
TL;DR: The distributions of neurons displaying immunoreactivity for two calciumbinding proteins, parvalbumin and 28Kd calbindin, were studied in the thalamus of M. fascicularis to determine that cells expressing the calcium binding proteins projected upon the cerebral cortex.
Abstract: The distributions of neurons displaying immunoreactivity for two calcium binding proteins, parvalbumin and 28Kd calbindin, were studied in the thalamus of M. fascicularis. Colocalization experiments were carried out to determine the extent to which parvalbumin- and calbindin-like immunoreactivity was found in the same cells and the extent to which either was localized in GABAergic interneurons. Anterograde and retrograde tracing experiments involving the fluorescent tracer, fast blue, were also used to determine that cells expressing the calcium binding proteins projected upon the cerebral cortex. In the dorsal thalamus, nuclei are distinguished by different patterns of parvalbumin-like and calbindin-like immunoreactivity. In certain nuclei, for example the lateral dorsal and anterior pulvinar, neurons express immunoreactivity for only one of the calcium binding proteins. In others, neurons in different layers, for example the dorsal lateral geniculate nucleus, or in different compartments, for example the intralaminar nuclei, express immunoreactivity for either parvalbumin or calbindin; in other nuclei, for example the ventral group, neurons are mixed and immunoreactivity for parvalbumin and calbindin is commonly colocalized. In the ventral thalamus and epithalamus, similar patterns are observed. Colocalization of parvalbumin- and GABA-immunoreactivity is found in all cells of the reticular nucleus but only in certain cells in selected nuclei of the dorsal thalamus, namely the dorsal lateral geniculate and magnocellular medial geniculate. No calbindin-positive cells are also GABA-positive. Most parvalbumin and/or calbindin positive cells in the dorsal thalamus project to the cerebral cortex, as indicated by the retrograde tracing studies, and many parvalbumin positive fibres entering the cerebral cortex could also be shown to contain fast blue anterogradely transported from a thalamic injection. Most of the major sensory and motor pathways entering the dorsal thalamus express parvalbumin immunoreactivity. The optic tract also expresses calbindin immunoreactivity but most other calbindin positive fibres entering the thalamus ascend in the midbrain tegmentum. The differential distributions of parvalbumin and calbindin implied by these results suggest that thalamic cells belonging to different functional systems and projecting differentially upon the cerebral cortex can be distinguished by differential expression of these or closely related calcium binding proteins. This may yield clues to their differential responsivity to afferent driving.
TL;DR: The results suggest that growth in a diffusion-limited space, reduction of oxygen concentration to physiological levels and control of toxic oxidation with physiological antioxidants can greatly improve the survival and neuritogenesis of isolated hippocampal neurons in primary culture.
TL;DR: The low variance in planktonic larval duration within species indicates that most damselfish are unable to delay metamorphosis following competency, which limits the potential for dispersal, especially when dispersal time between suitable habitats is greater than about 30 d.
Abstract: The plankton larval duration for 100 species of Pacific and Atlantic damselfishes was estimated from daily growth increments on the otolith of juvenile fish collected at various localities between July 1987 and September 1988. For newly-settled fishes, larval duration was determined by counting the entire number of increments present on the otolith, while for older juveniles estimates were made by counting the number of increments between the center of the otolith and a mark corresponding to settlement. We document the development of otolith formation during the period when eggs are incubated on the reef and show that daily increments are only accreted after larvae hatch and enter the planktonic phase. The planktonic larval duration for damselfish is shorter and less variable, both between and within species, compared to other groups of reef fishes such as wrasses and surgeonfishes. Larval duration ranged from 12 to 39 d. Average duration between species ranged from 13.1 to 35.2 d. The time spent in the plankton was not significantly correlated with geographic distribution when evaluated among species, however, genera with confined regional distribution have a shorter mean larval life than do widely distributed genera. Size at settlement was positively correlated with time spent in the plankton among species, but a significant correlation between these variables was only evident within one of ten species. The low variance in planktonic larval duration within species indicates that most damselfish are unable to delay metamorphosis following competency. This inability to postpone settlement limits the potential for dispersal, especially when dispersal time between suitable habitats is greater than about 30 d.
TL;DR: Policy issues that influenced the development of policies for inclusion of quality of life end points in certain Southwest Oncology Group clinical trials are reviewed and specific questionnaires with psychometric properties are recommended.
Abstract: In this presentation, issues that influenced the development of policies for inclusion of quality of life end points in certain Southwest Oncology Group clinical trials are reviewed. The key policies recommended by us and adopted by the Cancer Control Research Committee of the Southwest Oncology Group are as follows: (a) Begin assessment of quality of life in specific types of phase III protocols. (b) Always measure physical functioning, emotional functioning, symptoms (general and protocol specific), and global quality of life separately. (c) Include measures of social functioning and additional protocol-specific measures if resources permit. (d) Use patient-based questionnaires with psychometric properties that have been documented in published studies. In this review, we also recommend specific questionnaires. Our recommendations may prove useful for other cancer clinical trials groups and for multi-institution trials of treatment for chronic diseases.
TL;DR: In this article, the authors investigated mitogen-triggered Ca2+ signaling in individual cells of the human T-leukemia-derived line, Jurkat, using fura-2 imaging and patch-clamp recording techniques.
Abstract: A rapid rise in the level of cytosolic free calcium ([Ca2+]i) is believed to be one of several early triggering signals in the activation of T lymphocytes by antigen. Although Ca2+ release from intracellular stores and its contribution to Ca2+ signaling in many cell types is well documented, relatively little is known regarding the role and mechanism of Ca2+ entry across the plasma membrane. We have investigated mitogen-triggered Ca2+ signaling in individual cells of the human T-leukemia-derived line, Jurkat, using fura-2 imaging and patch-clamp recording techniques. Phytohemagglutinin (PHA), a mitogenic lectin, induces repetitive [Ca2+]i oscillations in these cells peaking at micromolar levels with a period of 90-120 s. The oscillations depend critically upon Ca2+ influx across the plasma membrane, as they are rapidly terminated by removal of extracellular Ca2+, addition of Ca(2+)-channel blockers such as Ni2+ or Cd2+, or membrane depolarization. Whole-cell and perforated-patch recording methods were combined with fura-2 measurements to identify the mitogen-activated Ca2+ conductance involved in this response. A small, highly selective Ca2+ conductance becomes activated spontaneously in whole-cell recordings and in response to PHA in perforated-patch experiments. This conductance has properties consistent with a role in T-cell activation, including activation by PHA, lack of voltage-dependent gating, inhibition by Ni2+ or Cd2+, and regulation by intracellular Ca2+. Moreover, a tight temporal correlation between oscillations of Ca2+ conductance and [Ca2+]i suggests a role for the membrane Ca2+ conductance in generating [Ca2+]i oscillations in activated T cells.
TL;DR: The data demonstrate definitively that both emigrating and premigratory trunk neural crest cells can be multipotent, giving rise not only to cells in multiple neural crest derivatives, but also to both neuronal and nonneuronal elements within a given derivative.
TL;DR: The model was used to predict the chance of a patient having nodal metastasis for any combination of risk factors, and identified five risk factors significantly associated with microscopic pelvic lymph node metastasis.
TL;DR: In this paper, neural tube cells with end feet in contact with the lumen, including premigratory neural crest cells, were labelled with a non-eleterious membrane intercalating vital dye, DiI.
Abstract: To permit a more detailed analysis of neural crest cell migratory pathways in the chick embryo, neural crest cells were labelled with a nondeleterious membrane intercalating vital dye, DiI. All neural tube cells with endfeet in contact with the lumen, including premigratory neural crest cells, were labelled by pressure injecting a solution of DiI into the lumen of the neural tube. When assayed one to three days later, migrating neural crest cells, motor axons, and ventral root cells were the only cells types external to the neural tube labelled with DiI. During the neural crest cell migratory phase, distinctly labelled cells were found along: (1) a dorsolateral pathway, under the epidermis, as well adjacent to and intercalating through the dermamyotome; and (2) a ventral pathway, through the rostral portion of each sclerotome and around the dorsal aorta as described previously. In contrast to those cells migrating through the sclerotome, labelled cells on the dorsolateral pathway were not segmentally arranged along the rostrocaudal axis. DiI-labelled cells were observed in all truncal neural crest derivatives, including subepidermal presumptive pigment cells, dorsal root ganglia, and sympathetic ganglia. By varying the stage at which the injection was performed, neural crest cell emigration at the level of the wing bud was shown to occur from stage 13 through stage 22. In addition, neural crest cells were found to populate their derivatives in a ventral-to-dorsal order, with the latest emigrating cells migrating exclusively along the dorsolateral pathway.