Showing papers by "Vanderbilt University published in 1993"

Cognitive, affective, and attribute bases of the satisfaction response.

Abstract: An attempt to extend current thinking on postpurchase response to include attribute satisfaction and dissatisfaction as separate determinants not fully reflected in either cognitive (i.e., expectancy disconfirmation) or affective paradigms is presented. In separate studies of automobile satisfaction and satisfaction with course instruction, respondents provided the nature of emotional experience, disconfirmation perceptions, and separate attribute satisfaction and dissatisfaction judgments. Analysis confirmed the disconfirmation effect and the effects of separate dimensions of positive and negative affect and also suggested a multidimensional structure to the affect dimensions. Additionally, attribute satisfaction and dissatisfaction were significantly related to positive and negative affect, respectively, and to overall satisfaction. It is suggested that all dimensions tested are needed for a full accounting of postpurchase responses in usage.

Spline Functions: Basic Theory

Abstract: This classic work continues to offer a comprehensive treatment of the theory of univariate and tensor-product splines. It will be of interest to researchers and students working in applied analysis, numerical analysis, computer science, and engineering. The material covered provides the reader with the necessary tools for understanding the many applications of splines in such diverse areas as approximation theory, computer-aided geometric design, curve and surface design and fitting, image processing, numerical solution of differential equations, and increasingly in business and the biosciences. This new edition includes a supplement outlining some of the major advances in the theory since 1981, and some 250 new references. It can be used as the main or supplementary text for courses in splines, approximation theory or numerical analysis.

The efficacy of psychological, educational, and behavioral treatment. Confirmation from meta-analysis.

Abstract: Conventional reviews of research on the efficacy of psychological, educational, and behavioral treatments often find considerable variation in outcome among studies and, as a consequence, fail to reach firm conclusions about the overall effectiveness of the interventions in question. In contrast meta-analytic reviews show a strong, dramatic pattern of positive overall effects that cannot readily be explained as artifacts of meta-analytic technique or generalized placebo effects. Moreover, the effects are not so small that they can be dismissed as lacking practical or clinical significance. Although meta-analysis has limitations, there are good reasons to believe that its results are more credible than those of conventional reviews and to conclude that well-developed psychological, educational, and behavioral treatment is generally efficacious.

NF-κB controls expression of inhibitor IκBα : evidence for an inducible autoregulatory pathway

Abstract: The eukaryotic transcription factor nuclear factor-kappa B (NF-kappa B) participates in many parts of the genetic program mediating T lymphocyte activation and growth. Nuclear expression of NF-kappa B occurs after its induced dissociation from its cytoplasmic inhibitor I kappa B alpha. Phorbol ester and tumor necrosis factor-alpha induction of nuclear NF-kappa B is associated with both the degradation of performed I kappa B alpha and the activation of I kappa B alpha gene expression. Transfection studies indicate that the I kappa B alpha gene is specifically induced by the 65-kilodalton transactivating subunit of NF-kappa B. Association of the newly synthesized I kappa B alpha with p65 restores intracellular inhibition of NF-kappa B DNA binding activity and prolongs the survival of this labile inhibitor. Together, these results show that NF-kappa B controls the expression of I kappa B alpha by means of an inducible autoregulatory pathway.

Appraisal components, core relational themes, and the emotions

Abstract: This study experimentally tests the contributions of specific appraisals, considered at both molecular (appraisal components) and molar (core relational themes) levels of analysis, to the experience of four emotions (anger, guilt, fear/anxiety, and sadness) using a two-stage directed imagery task. In Stage 1, subjects imagined themselves in scenarios designed to evoke appraisals hypothesised to produce either anger or sadness. In Stage 2, the scenarios unfolded in time to produce a second manipulation designed to systematically evoke the appraisals hypothesised to produce each of the four emotions under study. The results provided substantial support for the theoretically specified appraisal-emotion relationships for anger, guilt, and fear/ anxiety. However, support for the predictions for sadness was weaker, partially due to ineffective manipulation of the relevant appraisals. Implications for the further development and testing of emotion theory are discussed.

Dynamics of HIV infection of CD4+ T cells

Abstract: We examine a model for the interaction of HIV with CD4+ T cells that considers four populations: uninfected T cells, latently infected T cells, actively infected T cells, and free virus. Using this model we show that many of the puzzling quantitative features of HIV infection can be explained simply. We also consider effects of AZT on viral growth and T-cell population dynamics. The model exhibits two steady states, an uninfected state in which no virus is present and an endemically infected state, in which virus and infected T cells are present. We show that if N, the number of infectious virions produced per actively infected T cell, is less a critical value, Ncrit, then the uninfected state is the only steady state in the nonnegative orthant, and this state is stable. For N > Ncrit, the uninfected state is unstable, and the endemically infected state can be either stable, or unstable and surrounded by a stable limit cycle. Using numerical bifurcation techniques we map out the parameter regimes of these various behaviors. Oscillatory behavior seems to lie outside the region of biologically realistic parameter values. When the endemically infected state is stable, it is characterized by a reduced number of T cells compared with the uninfected state. Thus T-cell depletion occurs through the establishment of a new steady state. The dynamics of the establishment of this new steady state are examined both numerically and via the quasi-steady-state approximation. We develop approximations for the dynamics at early times in which the free virus rapidly binds to T cells, during an intermediate time scale in which the virus grows exponentially, and a third time scale on which viral growth slows and the endemically infected steady state is approached. Using the quasi-steady-state approx

Prediction of mortality and morbidity with a 6-minute walk test in patients with left ventricular dysfunction. SOLVD Investigators

Abstract: Objective. —To study the potential usefulness of the 6-minute walk test, a self-paced submaximal exercise test, as a prognostic indicator in patients with left ventricular dysfunction. Design. —Data were collected during a prospective cohort study, the Studies of Left Ventricular Dysfunction (SOLVD) Registry Substudy. Setting. —Twenty tertiary care hospitals in the United States, Canada, and Belgium. Participants. —A stratified random sample of 898 patients from the SOLVD Registry who had either radiological evidence of congestive heart failure and/or an ejection fraction of 0.45 or less were enrolled in the substudy and underwent a detailed clinical evaluation including a 6-minute walk test. Patients were followed up for a mean of 242 days. Outcome Measures. —Mortality and hospitalization. Results. —During follow-up, 52 walk-test participants (6.2%) died and 252 (30.3%) were hospitalized. Hospitalization for congestive heart failure occurred in 78 participants (9.4%), and the combined endpoint of death or hospitalization for congestive heart failure occurred in 114 walk-test participants (13.7%). Compared with the highest performance level, patients in the lowest performance level had a significantly greater chance of dying (10.23% vs 2.99%;P=.01), of being hospitalized (40.91% vs 19.90%;P=.002), and of being hospitalized for heart failure (22.16% vs 1.99%;P Conclusion. —The 6-minute walk test is a safe and simple clinical tool that strongly and independently predicts morbidity and mortality in patients with left ventricular dysfunction. (JAMA. 1993;270:1702-1707)

The war puzzle

Abstract: Part I. Preliminaries: Introduction 1. Conceptualizing war 2. Types of war 3. Power politics and war Part II. The Onset and Expansion of Wars of Rivalry: 4. Territorial continuity as a source of conflict leading to war 5. The realist road to war 6. The domestic prerequisites of wars of rivalry 7. Explaining world war: its scope, severity, and duration 8. Peace 9. Conclusion.

Social-Cognitive Mechanisms in the Development of Conduct Disorder and Depression

Abstract: CONTENTS INTRODucnON 559 Mental Processes in Social Behavior 560 SOCIAL-INFORMA nON-PROCESSING THEORY . ... . . . . . . . . . . . .. . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 560 Application to Single Behavioral Events 562 Application to Child Psychopathology 563 Critique ..... ... . . . . . . . . . . . . . . . . . . . . .. 571 KNOWLEDGE STRUCTURES THAT GUIDE PROCESSING 573 Relation to Aggressive Behavior 575 Relation to Depression .. ... 577 DEVELOPMENTAL PSYCHOPATHOLOGY OF CONDUCT DISORDER AND DEPRESSION '''''''''''' 578 CONCLUSION 580

Differential expression of multiple fork head related genes during gastrulation and axial pattern formation in the mouse embryo

Abstract: Four genes encoding fork-head-domain-containing proteins (FD genes) have been isolated from a mouse 8.5 days post coitum (p.c.) embryo cDNA library. Two are mouse homologues of rat HNF-3 beta and HNF-3 alpha. The other two are novel and have been named MF-1 and MF-2 (for mesoderm/mesenchyme fork head). Wholemount in situ hybridization of embryos between 6.5 and 9.5 days p. c. shows that each gene has a unique expression pattern. HNF-3 beta is expressed in the node, notochord, floor plate and gut, while HNF-3 alpha is mainly in the definitive endoderm and gut, but also in the floor plate of the midbrain. These results suggest that HNF-3 beta and HNF-3 alpha, in addition to their known functions as transcriptional activators in adult liver, play a role in body axis formation, neural tube patterning and definitive endoderm formation during gastrulation. MF-1 RNA is present in non-notochordal mesoderm, and in neural-crest-derived head mesenchyme, while MF-2 transcripts are found in the sclerotomes of the somites and in head mesenchyme, including that from neural crest. Studies on gastrulation stage embryos suggest that the early temporal and spatial patterns of HNF-3 beta, MF-1 and HNF-3 alpha correlate with populations of cells undergoing commitment to different developmental fates. A model is proposed linking FD gene expression with gastrulation events in the mouse.

Cloning and expression of a high-molecular-mass major antigen of Helicobacter pylori: evidence of linkage to cytotoxin production.

Abstract: A high-molecular-mass (120- to 128-kDa) Helicobacter pylori antigen has been associated with peptic ulcer disease. We created a bank of 40,000 random chromosomal fragments of H. pylori 84-183 by using lambda ZapII. Screening of this bank in Escherichia coli XL1-Blue with absorbed serum from an H. pylori-infected person permitted the isolation and purification of a clone with a 3.5-kb insert. Subcloning of this insert (pMC3) permitted the expression of a recombinant H. pylori protein that had a mass of approximately 96 kDa and that was recognized by the human serum. Sera that were obtained from H. pylori-infected persons and that recognized the native 120- to 128-kDa H. pylori antigen recognized the recombinant 96-kDa pMC3 protein to a significantly greater extent than did sera that did not recognize the native H. pylori antigen. All 19 H. pylori isolates producing the 120- to 128-kDa antigen hybridized with pMC3; none of 13 nonproducers did so (P < 0.001). Because all 15 isolates producing the vacuolating cytotoxin hybridized with pMC3, we called the gene cagA (cytotoxin-associated gene). Sequence analysis of pMC3 identified an open reading frame of 859 amino acids, without a termination codon. Parallel screening of a lambda gt11 library with human serum revealed positive plaques with identical 0.6-kb inserts and sequences matching the sequence of the downstream region of pMC3. To clone the full-length gene, we used the 0.6-kb fragment as a probe and isolated a clone with a 2.7-kb insert from the lambda ZapII genomic library. Nucleotide sequencing of this insert (pYB 2) revealed a 785-bp sequence that overlapped the downstream region of pMC3. Translation of the complete nucleotide sequence of cagA revealed an open reading frame of 1,181 amino acids yielding a protein of 131,517 daltons. There was no significant homology with any previously reported protein sequence. These findings indicate the cloning and characterization of a high-molecular-mass H. pylori antigen potentially associated with virulence and with cytotoxin production.

Nodal is a novel TGF-β-like gene expressed in the mouse node during gastrulation

Abstract: DURING gastrulation, the three germ layers of the embryo are formed and organized along the anterior-posterior body axis. In the mouse, gastrulation involves the delamination of ectodermal cells through the primitive streak and their differentiation into mesoderm1. These processes do not occur in embryos homozygous for a retrovirally induced recessive prenatal lethal mutation, the strain 413-d insertional mutation23. Instead of giving rise to mesoderm, embryonic ectoderm in 413-d mutants overproliferates and then rapidly degenerates, although extraembrysonic lineages remain viable2. Here we isolate a candidate for the mutated gene which encodes a new member of the transforming growth factor-p (TGF-p) superfamily4. Expression is first detected in primitive streak-stage embryos at about the time of mesoderm formation. It then becomes highly localized in the node at the anterior of the primitive streak. This region is analogous to chick Hensen's node and Xenopus dorsal lip (Spemann's organizer), which can induce secondary body axes when grafted into host embryos (reviewed in refs 5 and 6). Our findings suggest that this gene, named nodal, encodes a signalling molecule essential for mesoderm formation and subsequent organization of axial structures in early mouse development.

Acute motor axonal neuropathy : a frequent cause of acute flaccid paralysis in China

Abstract: In northern China, annual epidemics of acute-onset flaccid paralysis diagnosed clinically as Guillain-Barre syndrome have been recognized for at least 20 years. On the basis of an historical analysis of more than 3,200 patients, distinctive features include most cases occurring during the summer months among children and young adults, most of whom reside in rural areas. Of 90 patients with acute flaccid paralysis, 88 had a distinctive pattern that shares clinical and cerebrospinal fluid findings with demyelinating Guillain-Barre syndrome, but that differs from Guillain-Barre syndrome physiologically and pathologically. The clinical course is marked by rapidly progressive ascending tetraparesis, often with respiratory failure, but without fever, systemic illness, or sensory involvement. Cerebrospinal fluid is acellular, and elevations of protein content occur in the second or third week of illness. Electrodiagnostic studies show normal motor distal latencies and limb conduction velocities, but reduced compound muscle action potential amplitudes. Sensory nerve action potentials and, when elicitable, F waves are within the range of normal. Recovery is usually good. Autopsy studies have shown Wallerian-like degeneration of motor fibers. These studies establish that this is a distinctive syndrome, distinguishable from poliomyelitis and demyelinating Guillain-Barre syndrome.

Breast cancer risk associated with proliferative breast disease and atypical hyperplasia

Abstract: Background. Women with proliferative breast disease (PD) have been observed to have an increased risk of breast cancer. The authors evaluated the effect of PD on breast cancer risk in a case–control study among participants of the Breast Cancer Detection Demonstration Project (BCDDP). Methods. More than 280,000 women were screened in the BCDDP at 29 centers. Study subjects were selected from BCDDP participants who underwent biopsy that revealed benign breast tissue. There were five BCDDP centers for which histologic slides were available on more than 85% of the benign biopsy specimens. Case patients for this study were the 95 women from these five centers who had breast cancer develop during follow-up. Two matched control patients who did not have breast cancer develop were selected for each case. The biopsy slides were reviewed by two pathologists who were blinded with regard to cancer outcome. Results. Women with atypical hyperplasia (AH) had 4.3 times the breast cancer risk of women without PD (95% confidence interval [CI], 1.7–11). In women with PD lacking AH, the relative risk was 1.3 (95% CI, 0.77–2.2). A family history of breast cancer (FH) increased breast cancer risk 2.4 times (95% CI, 1.4–4.3). The joint occurrence of FH and AH had a strong synergistic effect on breast cancer risk. Conclusions. AH is a reliable marker of increased breast cancer risk among women undergoing breast biopsy.

Ground-state correlation energies for atomic ions with 3 to 18 electrons.

Abstract: Recently Davidson [ital et] [ital al]. [Phys. Rev. A 44, 7071 (1991)] have estimated nonrelativistic correlation energies and relativistic corrections to ionization potentials for atomic ions with up to 10 electrons. In this work, this approach is extended to atomic ions with 11 to 18 electrons. The correlation energies for 3- to 10-electron atomic ions are also recomputed using more recent experimental and theoretical data. Unlike other work the method focuses on the correlation contribution to the individual ionization energies which are obtained by comparing experimental data with relativistic complete-valence-space energies. [ital Ab] [ital initio] estimates of correlation contributions to the ionization energies with extensive configuration-interaction calculations of 3- to 10-electron atomic ions with nuclear charge from 4 through 10 and 18, 36, 50, 72, 100, and 144 have been obtained. The correlation energies obtained from some density-functional models are also compared to these correlation energy data.

Tonotopic organization, architectonic fields, and connections of auditory cortex in macaque monkeys

Abstract: Microelectrode recordings were used to investigate the tonotopic organization of auditory cortex of macaque monkeys and guide the placement of injections of wheat germ agglutinin-horse radish peroxidase (WGA-HRP) and fluorescent dyes. Anatomical and physiological results were later related to histological distinctions in the same brains after sections were processed for cytoarchitecture, myeloarchitecture, acetylcholinesterase (AchE), or cytochrome oxidase (CO). The experiments produced several major findings. (1) Neurons throughout a broad expanse of cortex were highly responsive to pure tones, and best frequencies could be determined for neurons in arrays of recording sites. (2) The microelectrode recordings revealed two systematic representations of tone frequencies, the primary area (AI) and a primary-like rostral field (R) as previously described. The representation of high to low frequency tones in A1 was largely caudorostral along the plane of the sulcus. A reversal of the order of representation of frequencies occurred in R. (3) AI and R together were coextensive with a koniocellular, densely myelinated zone that expressed high levels of AchE and CO. These architectonic features were somewhat less pronounced in R than AI, but a clear border between the two areas was not apparent. (4) Cortex bordering AI and R was less responsive to tones, but when best frequencies for neurons could be determined, they matched those for adjoining parts of AI and R. (5) Architectonically distinct regions were apparent within some of the cortex bordering AI and R. (6) The major ipsilateral cortical connections of AI were with R and cortex immediately lateral and medial to AI. (7) Callosal connections of AI were predominantly with matched locations in the opposite AI, but they also included adjoining fields. (8) Neurons in the ventral (MGV), medial (MGM), and dorsal (MGD) nuclei of the medial geniculate complex projected to AI and cortex lateral to AI. (9) Injections in cortex responsive to high frequency tones labeled more dorsal parts of MGV than injections in cortex responsive to low frequency tones.

Non-Hodgkin's Lymphomas

Abstract: Part 1 Lymphomagenesis: Lymphocyte differentiation Adult T-cell leukaemia/Lymphoma - a model of retrovirus-induced lymphomagenesis Burkitt's lymphoma and Epstein-Barr virus-associated lymphoid malignancies - models for lymphomagenesis T(14 18) translocation. Part 2 Methods: Histological and immunohistochemical methods Genotype. Part 3 Nodal Non-Hodgkin's Lymphomas: The normal lymph node - structure and function Histological classification Staging of NHLs Analytical study of the different subtypes of NHLs - clinical, histological and immunohistochemical aspects NHLs in childhood NHLs associated with HIV infection. Part 4 Extra-Nodal Non-Hodgkin's lymphomas: Malignant lymphomas of mucosa-associated lymphoid tissues Primary gastrointestinal NHLs Pathology of gastro-intestinal NHLs Cutaneous lymphomas NHLs of the Mediastinum NHLs of the lung Bone marrow involvement Blood involvement in chronic (mature) B & T lymphoproliferative syndromes Liver involvement Spleen involvement Extra-cranial head-and-neck NHLs Central nervous system involvement NHLs of bone Urogenital localizations. Part 5 Treatment of Non-Hodgkin's Lymphomas: Methodology and problems in the comparison of results Treatment of lowgrade NHLs The role of radiation therapy Treatment of aggressive lymphomas (intermediate and highgrade) Intensive chemoradiotherapy and bone-marrow transplantation Salvage therapy after failure Treatment of NHLs in childhood.

Formative Evaluation of Academic Progress: How Much Growth Can We Expect?.

Abstract: The purpose of this study was to examine students' weekly rates of academic growth, or slopes of achievement, when Curriculum-Based Measurement (CBM) is conducted repeatedly over 1 year. Using stan...

The Emergence of Chronic Peer Victimization in Boys' Play Groups

Abstract: This investigation utilized a contrived play group procedure to examine the behavioral patterns leading to chronic victimization by peers in middle childhood. 30 play groups, each of which consisted of 6 unacquainted African-American 6-year-old or 8-year-old boys, met for 45-min sessions on 5 consecutive days. Play group interactions were videotaped and then examined. 13 boys who came to be chronically victimized by their play group peers were identified, along with matched nonvictim contrasts. Victims demonstrated lower rates of assertive behaviors, such as persuasion attempts and social conversation initiatives, and higher rates of nonassertive behaviors, such as submissions to peers' social initiatives, than contrasts. This nonassertive behavior pattern appears to have preceded the development of chronic victimization. Children who eventually emerged as victims were pervasively submissive, beginning in the initial 2 sessions. However, marked individual differences in victimization by peers did not become apparent until the final 3 sessions. These data provide evidence of strong linkages between submissive social behavior and the emergence of chronic victimization by peers.

Neural basis of saccade target selection in frontal eye field during visual search

Abstract: CONSPICUOUS visual features commonly attract gaze1,2, but how the brain selects targets for eye movements is not known. We investigated target selection in rhesus monkeys performing a visual search task3 by recording neurons in the frontal eye field, an area known to be responsible for generating purposive eye movements4,5. Neurons with combined visual- and eye movement-related activity were analysed. We found that the initial visual responses to search stimulus arrays were the same whether the target or a distractor was in the response field. We also found that the neural activity evolved to specify target location before the execution of eye movements, ultimately peaking when the target was in the response field and being suppressed when the target was beside but not distant from the response field. These results demonstrate a possible mechanism by which a desired target is fixated and inappropriate eye movements are prevented.

The staged celiotomy for trauma. Issues in unpacking and reconstruction.

Abstract: OBJECTIVE: This article describes the important clinical events and decisions surrounding the reconstruction/unpacking portion of the staged celiotomy for trauma. METHODS: Of 13,817 consecutive trauma admissions, 1175 received trauma celiotomies. Of these, 107 patients (9.1%) underwent staged celiotomy with abdominal packing. The authors examined medical records to identify and characterize: (1) indications and timing of reconstruction, (2) criteria for emergency return to the operating room, (3) complications after reconstruction, and (4) abdominal compartment syndrome (ACS). RESULTS: Fifty-eight patients (54.2%) survived to reconstruction, 43 (74.1%) survived to discharge; 9 patients (15.5%) were returned to the operating room for bleeding; 13 patients required multiple packing procedures. There were 117 complications; 8 patients had positive blood cultures, abdominal abscesses developed in 6 patients, and ACS developed in 16 patients. CONCLUSIONS: 1. Reconstruction should occur after temperature, coagulopathy, and acidosis are corrected, usually within 36 hours after the damage control procedure. 2. Emergent reoperation should occur in any normothermic patient with unabated bleeding (greater than 2 U packed cells/hr). 3. ACS occurs in 15% of patients and is characterized by high peak inspiratory pressure, CO2 retention, and oliguria. Lethal reperfusion syndrome is common but preventable.

Priming immunization determines T helper cytokine mRNA expression patterns in lungs of mice challenged with respiratory syncytial virus.

Abstract: Defining the mechanism for the vaccine-enhanced illness associated with respiratory syncytial virus (RSV) is critical for advancing RSV vaccine development. Previous studies in which infants were vaccinated with formalin-inactivated alum-precipitated whole virus did not protect from RSV infection, and those infected had a high incidence of severe illness. In contrast, previous clinical trials evaluating live attenuated RSV showed no associated vaccine-enhanced illness. We have used a mouse model to explore the immunopathogenesis of RSV infection. In this study cytokine mRNA expression was examined using 32P-labeled oligonucleotide probes in Northern blot analyses of polyA RNA extracted from lungs of mice primed with various vaccine preparations then challenged nasally with live RSV. We have shown that upon challenge, priming of mice with inactivated virus or subunit F glycoprotein induced a pattern of cytokine mRNA expression suggesting a dominant Th2-like lymphocyte response (relative increase in IL-4 mRNA expression). In contrast, challenge of mice primed with live RSV by parenteral or mucosal routes induced a Th1-like pattern of cytokine mRNA expression (relative decrease in IL-4 mRNA expression compared to IFN-gamma mRNA expression). Thus, the formulation and route of delivery of vaccine products can influence the pattern of cytokine expression in lung upon RSV challenge.

Anti-transforming growth factor (TGF)-beta antibodies inhibit breast cancer cell tumorigenicity and increase mouse spleen natural killer cell activity. Implications for a possible role of tumor cell/host TGF-beta interactions in human breast cancer progression.

Abstract: TGF-beta effects on angiogenesis, stroma formation, and immune function suggest its possible involvement in tumor progression. This hypothesis was tested using the 2G7 IgG2b, which neutralizes TGF-beta 1, -beta 2, and -beta 3, and the MDA-231 human breast cancer cell line. Inoculation of these cells in athymic mice decreases mouse spleen natural killer (NK) cell activity. Intraperitoneal injections of 2G7 starting 1 d after intraperitoneal inoculation of tumor cells suppressed intraabdominal tumor and lung metastases, whereas the nonneutralizing anti-TGF-beta 12H5 IgG2a had no effect. 2G7 transiently inhibited growth of established MDA-231 subcutaneous tumors. Histologically, both 2G7-treated and control tumors were identical. Intraperitoneal administration of 2G7 resulted in a marked increase in mouse spleen NK cell activity. 2G7 did not inhibit MDA-231 primary tumor or metastases formation, nor did it stimulate NK cell-mediated cytotoxicity in beige NK-deficient nude mice. Finally, serum-free conditioned medium from MDA-231 cells inhibited the NK cell activity of human blood lymphocytes. This inhibition was blocked by the neutralizing anti-TGF-beta 2G7 antibody but not by a nonspecific IgG2. These data support a possible role for tumor cell TGF-beta in the progression of mammary carcinomas by suppressing host immune surveillance.