Medicine and Health Sciences Commons^™

Discrimination Of Computer-Graphic Stimuli By Mice: A Method For The Behavioral Characterization Of Transgenic And Gene-Knockout Models., T J Bussey, L M Saksida, L A Rothblat

Brain and Mind Institute Researchers' Publications

An automated method is described for the behavioral testing of mice in an apparatus that allows computer-graphic stimulus material to be presented. Mice responded to these stimuli by making a nose-poke toward a computer monitor that was equipped with a touchscreen attachment for detecting responses. It was found that C57BL/6 mice were able to solve single-pair visual discriminations as well as 3-pair concurrent visual discriminations. The finding that mice are capable of complex visual discriminations introduces the possibility of testing mice on nonspatial tasks that are similar to those used with rats, monkeys, and humans. Furthermore, the method seems particularly …

Tractor Driving Among Kentucky Farm Youth: Results From The Farm Family Health And Hazard Surveillance Project, Steven R. Browning, Susan C. Westneat, Raeanne Szeluga

Epidemiology and Environmental Health Faculty Publications

This article documents the extent of children's involvement in tractor operations among a representative sample of Kentucky children living and working on family farms. Specifically, we describe children's exposures to tractor-related work activities, profile their use of the tractor (number of days worked), and assess compliance with generally recommended safety measures, such as using tractors equipped with ROPS (rollover protective structures), avoiding riding as passengers on tractors, and operating tractors on public roadways. Data for this study were collected in 1994 and 1995 as part of the NIOSH-sponsored Farm Family Health and Hazard Surveillance Project (FFHHSP). Despite recognition in the …

Internet Facilitation Of Opioid Dependence., D Z Lieberman

Psychiatry and Behavioral Sciences Faculty Publications

No abstract provided.

An Open-Label Trial Of Tomoxetine In Pediatric Attention Deficit Hyperactivity Disorder., Christopher J. Kratochvil, Daryl Bohac, Martin Harrington, Natalie Baker, Diane E. May, William J. Burke

Journal Articles: Psychiatry

OBJECTIVE: To collect pilot data assessing the safety, tolerability, and efficacy of tomoxetine, a nonstimulant norepinephrine enhancer, in pediatric attention deficit hyperactivity disorder (ADHD).

METHODS: An open-label trial of tomoxetine in pediatric ADHD was conducted as part of a multisite clinical trial. Following a baseline assessment, an ascending dose titration was completed during 10 weekly visits.

RESULTS: Ten subjects were enrolled at baseline, with eight completing the study. Seven of the eight remaining subjects met efficacy criteria. Significant decreases in symptom severity ratings by parents and study investigators were found. The medication was well tolerated, with transient appetite suppression the …

Impact Of Smoking On The Outcome Of Anterior Cervical Arthrodesis With Interbody Or Strut-Grafting., Alan Hilibrand, Mark A. Fye, Sanford E. Emery, Mark A. Palumbo, Henry H. Bohlman

Rothman Institute Papers

BACKGROUND: An increased rate of pseudarthrosis has been documented following posterolateral lumbar spine grafting in patients who smoke. This same relationship has been assumed for anterior cervical interbody grafting, but to our knowledge it has never been proven. This study compared the long-term radiographic and clinical results of smokers and nonsmokers who had undergone arthrodesis with autogenous bone graft following multi-level anterior cervical decompression for the treatment of cervical radiculopathy or myelopathy, or both.

METHODS: One hundred and ninety patients were followed clinically and radiographically for at least two years (range, two to fifteen years). Fifty-nine of the patients had …

Characterization Of The Cd154-Positive And Cd40-Positive Cellular Subsets Required For Pathogenesis In Retrovirus-Induced Murine Immunodeficiency, Kathy A. Green, Randolph J. Noelle, Brigit G. Durell, William R. Green

Dartmouth Scholarship

Genetically susceptible C57BL/6 (B6) mice that are infected with the LP-BM5 isolate of murine retroviruses develop profound splenomegaly, lymphadenopathy, hypergammaglobulinemia, terminal B-cell lymphomas, and an immunodeficiency state bearing many similarities to the pathologies seen in AIDS. Because of these similarities, this syndrome has been called murine AIDS (MAIDS). We have previously shown that CD154 (CD40 ligand)-CD40 molecular interactions are required both for the initiation and progression of MAIDS. Thus, in vivo anti-CD154 monoclonal antibody (MAb) treatment inhibited MAIDS symptoms in LP-BM5-infected wild-type mice when either a short course of anti-CD154 MAb treatment was started on the day of infection or …

Impaired Fast-Spiking, Suppressed Cortical Inhibition, And Increased Susceptibility To Seizures In Mice Lacking Kv3.2 K+ Channel Proteins, David Lau, Eleazar Vega-Saenz De Miera, Diego Contreras, Alan Chow, Richard Paylor, Christopher S. Leonard, Bernardo Rudy

NYMC Faculty Publications

Voltage-gated K(+) channels of the Kv3 subfamily have unusual electrophysiological properties, including activation at very depolarized voltages (positive to -10 mV) and very fast deactivation rates, suggesting special roles in neuronal excitability. In the brain, Kv3 channels are prominently expressed in select neuronal populations, which include fast-spiking (FS) GABAergic interneurons of the neocortex, hippocampus, and caudate, as well as other high-frequency firing neurons. Although evidence points to a key role in high-frequency firing, a definitive understanding of the function of these channels has been hampered by a lack of selective pharmacological tools. We therefore generated mouse lines in which one …

Mrnas Encoding Aquaporins Are Present During Murine Preimplantation Development., H Offenberg, L C Barcroft, A Caveney, D Viuff, P D Thomsen, A J Watson

Obstetrics & Gynaecology Publications

The present study was conducted to investigate the mechanisms underlying fluid movement across the trophectoderm during blastocyst formation by determining whether aquaporins (AQPs) are expressed during early mammalian development. AQPs belong to a family of major intrinsic membrane proteins and function as molecular water channels that allow water to flow rapidly across plasma membranes in the direction of osmotic gradients. Ten different AQPs have been identified to date. Murine preimplantation stage embryos were flushed from the oviducts and uteri of superovulated CD1 mice. Reverse transcription-polymerase chain reaction (RT-PCR) methods employing primer sets designed to amplify conserved sequences of AQPs (1-9) …

Prolonged Cyclooxygenase-2 Induction In Neurons And Glia Following Traumatic Brain Injury In The Rat, Kenneth I. Strauss, Mary F. Barbe, Renee Marshall Demarest, Ramesh Raghupathi, Samir Mehta, Raj K. Narayan

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Cyclooxygenase-2 (COX2) is a primary inflammatory mediator that converts arachidonic acid into precursors of vasoactive prostaglandins, producing reactive oxygen species in the process. Under normal conditions COX2 is not detectable, except at low abundance in the brain. This study demonstrates a distinctive pattern of COX2 increases in the brain over time following traumatic brain injury (TBI). Quantitative lysate ribonuclease protection assays indicate acute and sustained increases in COX2 mRNA in two rat models of TBI. In the lateral fluid percussion model, COX2 mRNA is significantly elevated (>twofold, p < 0.05, Dunnett) at 1 day postinjury in the injured cortex and bilaterally in the hippocampus, compared to sham-injured controls. In the lateral cortical impact model (LCI), COX2 mRNA peaks around 6 h postinjury in the ipsilateral cerebral cortex (fivefold induction, p < 0.05, Dunnett) and in the ipsilateral and contralateral hippocampus (two- and six-fold induction, respectively, p < 0.05, Dunnett). Increases are sustained out to 3 days postinjury in the injured cortex in both models. Further analyses use the LCI model to evaluate COX2 induction. Immunoblot analyses confirm increased levels of COX2 protein in the cortex and hippocampus. Profound increases in COX2 protein are observed in the cortex at 1-3 days, that return to sham levels by 7 days postinjury (p < 0.05, Dunnett). The cellular pattern of COX2 induction following TBI has been characterized using immunohistochemistry. COX2-immunoreactivity (-ir) rises acutely (cell numbers and intensity) and remains elevated for several days following TBI. Increases in COX2-ir colocalize with neurons (MAP2-ir) and glia (GFAP-ir). Increases in COX2-ir are observed in cerebral cortex and hippocampus, ipsilateral and contralateral to injury as early as 2 h postinjury. Neurons in the ipsilateral parietal, perirhinal and piriform cortex become intensely COX2-ir from 2 h to at least 3 days postinjury. In agreement with the mRNA and immunoblot results, COX2-ir appears greatest in the contralateral hippocampus. Hippocampal COX2-ir progresses from the pyramidal cell layer of the CA1 and CA2 region at 2 h, to the CA3 pyramidal cells and dentate polymorphic and granule cell layers by 24 h postinjury. These increases are distinct from those observed following inflammatory challenge, and correspond to brain areas previously identified with the neurological and cognitive deficits associated with TBI. While COX2 induction following TBI may result in selective beneficial responses, chronic COX2 production may contribute to free radical mediated cellular damage, vascular dysfunction, and alterations in cellular metabolism. These may cause secondary injuries to the brain that promote neuropathology and worsen behavioral outcome.

Eye Position Signal Modulates A Human Parietal Pointing Region During Memory-Guided Movements., J F Desouza, S P Dukelow, J S Gati, R S Menon, R A Andersen, T Vilis

Brain and Mind Institute Researchers' Publications

Using functional magnetic resonance imaging, we examined the signal in parietal regions that were selectively activated during delayed pointing to flashed visual targets and determined whether this signal was dependent on the fixation position of the eyes. Delayed pointing activated a bilateral parietal area in the intraparietal sulcus (rIPS), rostral/anterior to areas activated by saccades. During right-hand pointing to centrally located targets, the left rIPS region showed a significant increase in activation when the eye position was rightward compared with leftward. As expected, activation in motor cortex showed no modulation when only eye position changed. During pointing to retinotopically identical …

Children Of Alcoholics: An Update., D Z Lieberman

Psychiatry and Behavioral Sciences Faculty Publications

One of four children in the United States lives in a family in which the child is exposed to alcoholism. Children of alcoholics (COAs) are two to ten times more likely to develop alcoholism than non-COAs. This paper reviews studies that have attempted to identify risk factors that mediate the increased vulnerability and the protective factors that moderate the risk. Factors discussed include parental antisocial personality disorder, externalizing behavior, internalizing symptoms, differential response to the effects of alcohol, and positive and negative alcohol-related expectancies. The heterogeneous nature of COAs is emphasized, and some of the challenges related to treatment and …

Navigation-Related Structural Change In The Hippocampi Of Taxi Drivers, E A Maguire, D G Gadian, Ingrid Johnsrude, C D Good, J Ashburner, R S Frackowiak, C D Frith

Brain and Mind Institute Researchers' Publications

Structural MRIs of the brains of humans with extensive navigation experience, licensed London taxi drivers, were analyzed and compared with those of control subjects who did not drive taxis. The posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects. A more anterior hippocampal region was larger in control subjects than in taxi drivers. Hippocampal volume correlated with the amount of time spent as a taxi driver (positively in the posterior and negatively in the anterior hippocampus). These data are in accordance with the idea that the posterior hippocampus stores a spatial representation of the environment …

Ubinuclein, A Novel Nuclear Protein Interacting With Cellular And Viral Transcription Factors., S Aho, M Buisson, T Pajunen, Y W Ryoo, J F Giot, H Gruffat, A Sergeant, Jouni Uitto

Department of Dermatology and Cutaneous Biology Faculty Papers

The major target tissues for Epstein-Barr virus (EBV) infection are B lymphocytes and epithelial cells of the oropharyngeal zone. The product of the EBV BZLF1 early gene, EB1, a member of the basic leucine-zipper family of transcription factors, interacts with both viral and cellular promoters and transcription factors, modulating the reactivation of latent EBV infection. Here, we characterize a novel cellular protein interacting with the basic domains of EB1 and c-Jun, and competing of their binding to the AP1 consensus site. The transcript is present in a wide variety of human adult, fetal, and tumor tissues, and the protein is …

The Pl(A2) Polymorphism Of Integrin Beta(3) Enhances Outside-In Signaling And Adhesive Functions., K Vinod Vijayan, Pascal J. Goldschmidt-Clermont, Christine Roos, Paul F. Bray

Cardeza Foundation for Hematologic Research

Genetic factors are believed to influence the development of arterial thromboses. Because integrin alpha(IIb)beta(3) plays a crucial role in thrombus formation, we analyzed receptor adhesive properties using Chinese hamster ovary and human kidney embryonal 293 cells overexpressing the Pl(A1) or Pl(A2) polymorphic forms of alpha(IIb)beta(3). Soluble fibrinogen binding was no different between Pl(A1) and Pl(A2) cells, either in a resting state or when alpha(IIb)beta(3) was activated with anti-LIBS6. Pl(A1) and Pl(A2) cells bound equivalently to immobilized fibronectin. In contrast, significantly more Pl(A2) cells bound to immobilized fibrinogen in an alpha(IIb)beta(3)-dependent manner than did Pl(A1) cells. Disruption of the actin cytoskeleton …

Sulfa Or Sulfone Prophylaxis And Geographic Region Predict Mutations In The Pneumocystis Carinii Dihydropteroate Synthase Gene, Laurence Huang, Charles B. Beard, Jennifer Creasman, Deborah A. Levy, Jeffrey S. Duchin, Sherline Lee, Norman Pieniazek, Jane L. Carter, Carlos Del Rio, David Rimland, Thomas R. Navin

Journal Articles: Epidemiology

To determine factors associated with mutations in the Pneumocystis carinii dihydropteroate synthase (DHPS) gene, a prospective study of human immunodeficiency virus (HIV)-infected patients with confirmed P. carinii pneumonia was conducted in Atlanta, Seattle, and San Francisco. Clinical information was obtained from patient interview and chart abstraction. DHPS genotype was determined from DNA sequencing. Overall, 76 (68.5%) of 111 patients had a mutant DHPS genotype, including 22 (81.5%) of 27 patients from San Francisco. In multivariate analysis, sulfa or sulfone prophylaxis and study site were independent predictors of a mutant genotype. Fourteen (53.8%) of 26 patients who were newly diagnosed with …

Intimate Partner Violence Among Men And Women In South Carolina, 1998, Ann L. Coker, Christina Derrick, Julia L. Lumpkin, Robert Oldendick, R H. Potter

CRVAW Faculty Journal Articles

Few studies provide population-based estimates of intimate partner violence (IPV) for men and women, especially at the state level. IPV may result in adverse health effects for victims and perpetrators (1-3). To estimate the lifetime incidence of IPV by type of violence (e.g., physical, sexual, and perceived emotional abuse) and to explore demographic correlates of reporting IPV among men and women, the South Carolina Department of Health and Environmental Control and the University of South Carolina conducted a population-based random-digit-dialed telephone survey of adults in the state. This report summarizes the results of the survey, which indicated that approximately 25% …

Four Clinical Tests Of Sacroiliac Joint Dysfunction: The Association Of Test Results With Innominate Torsion Among Patients With And Without Low Back Pain, Pamela Levangie

All PTHMS Faculty Publications

Background and Purpose. The purpose of this study was to assess the association between innominate torsion (asymmetric anteroposterior positioning of the pelvic innominates) and the Gillet, standing forward flexion, sitting forward flexion, and supine-to-sit tests. Subjects. A sample of 21- to 50-year-old patients with low back pain (n=150) and a comparison group of patients with upper-extremity impairments (n=138) were recruited from outpatient physical therapy facilities. Methods. The association of single and combined test results with innominate torsion (calculated from pelvic landmark data) and with presence or absence of low back pain were estimated via odds ratios, sensitivities, specificities, and predictive …

Global Cns Gene Transfer For A Childhood Neurogenetic Enzyme Deficiency: Canavan Disease., Paola Leone, Christopher G Janson, Scott J Mcphee, Matthew J During

Department of Neurosurgery Faculty Papers

The neurogenetic prototypic disease on which we chose to test our gene therapy strategy is Canavan disease (CD). CD is an autosomal recessive leukodystrophy associated with spongiform degeneration of the brain. At present the disease is uniformly fatal in affected probands. CD is characterized by mutations in the aspartoacylase (ASPA) gene, resulting in loss of enzyme activity. In this review, recent evidence is summarized on the etiology and possible treatments for CD. In particular, we discuss two gene delivery systems representing recent advances in both viral and liposome technology: a novel cationic liposome-polymer-DNA (LPD) complex, DCChol/DOPE-protamine, as well as recombinant …

Small Bowel Strangulation As Yet Another Complication Of The Rectus Abdominis Donor Site., Geoffrey G. Hallock Md

Department of Surgery

No abstract provided.

Radiculopathy And Myelopathy At Segments Adjacent To The Site Of A Previous Anterior Cervical Arthrodesis., Alan S. Hilibrand, Gregory D. Carlson, M A Palumbo, P K Jones, H H Bohlman

Rothman Institute Papers

BACKGROUND: We studied the incidence, prevalence, and radiographic progression of symptomatic adjacent-segment disease, which we defined as the development of new radiculopathy or myelopathy referable to a motion segment adjacent to the site of a previous anterior arthrodesis of the cervical spine.

METHODS: A consecutive series of 374 patients who had a total of 409 anterior cervical arthrodeses for the treatment of cervical spondylosis with radiculopathy or myelopathy, or both, were followed for a maximum of twenty-one years after the operation. The annual incidence of symptomatic adjacent-segment disease was defined as the percentage of patients who had been disease-free at …

Home Observation For Asymptomatic Coin Ingestion: Acceptance And Outcomes. The New York State Poison Control Center Coin Ingestion Study Group., Gregory P. Conners, D J. Cobaugh, R Feinberg, R Lucanie, T Caraccio, C M. Stork

Manuscripts, Articles, Book Chapters and Other Papers

OBJECTIVES: To obtain preliminary estimates of the acceptance rate and the frequency of adverse outcomes, and to identify issues related to acceptance, associated with management of asymptomatic pediatric coin ingestion by home observation, in preparation for a large-scale prospective study.

METHODS: Scripted telephone follow-up of callers who had reported asymptomatic pediatric coin ingestions to one of five poison control centers six to 36 months previously, which had been managed by home observation.

RESULTS: Of the 67 callers enrolled, 41 (67%) reported contacting a physician regarding the coin ingestion, despite home observation instruction by poison control center personnel. Those who did …

The Effects Of Free Fatty Acids On Gluconeogenesis And Glycogenolysis In Normal Subjects, X Chen, N Iqbal, G Boden

Rowan-Virtua School of Osteopathic Medicine Departmental Research

We have quantitatively determined gluconeogenesis (GNG) from all precursors, using a novel method employing 2H20 to address the question of whether changes in plasma free fatty acids (FFA) affect GNG in healthy, nonobese subjects. In the first study (n = 6), plasma FFA were lowered at 16 to 20 hours with nicotinic acid (NA) and were then allowed to rise at 20 to 24 hours (FFA rebound after administration of NA). FFA decreased from 387 microM at 16 hours to 43 microM at 20 hours, and then rebounded to 1,823 microM at 24 hours. GNG decreased from 58.1% at 16 …

Functionally Dissociating Aspects Of Event Memory: The Effects Of Combined Perirhinal And Postrhinal Cortex Lesions On Object And Place Memory In The Rat., T J Bussey, J L Muir, J P Aggleton

Brain and Mind Institute Researchers' Publications

Reciprocal interactions between the hippocampus and the perirhinal and parahippocampal cortices form core components of a proposed temporal lobe memory system. For this reason, the involvement of the hippocampus in event memory is thought to depend on its connections with these cortical areas. Contrary to these predictions, we found that NMDA-induced lesions of the putative rat homologs of these cortical areas (perirhinal plus postrhinal cortices) did not impair performance on two allocentric spatial tasks highly sensitive to hippocampal dysfunction. Remarkably, for one of the tasks there was evidence of a facilitation of performance. The same cortical lesions did, however, disrupt …

Evaluating Histories Of Substance Abuse In Cases Involving The Termination Of Parental Rights, Richard C. Boldt

Journal of Health Care Law and Policy

No abstract provided.

Aneuploidy Frequencies In Semen Fractions From Ten Oligoasthenoteratozoospermic Patients Donating Sperm For Intracytoplasmic Sperm Injection, Jerome Pfeffer, Myung-Geol Pang, Stanton F. Hoegerman, Christopher J. Osgood, M. W. Stacey, Jacob Mayer, Sergio Oehninger, William G. Kearns

Biological Sciences Faculty Publications

Objective: To determine aneuploidy frequencies in pellet and swim-up semen fractions from 10 infertile men with severe oligoasthenoteratozoospermia (OAT) who were donating sperm for intracytoplasmic sperm injection and to determine whether the swim-up isolation method would successfully separate aneuploid from haploid sperm.

Design: Prospective study.

Setting: Infertility clinic and molecular genetics laboratory.

Patient(s): Ten patients with severe OAT.

Intervention(s): Cytogenetic analyses by fluorescence in situ hybridization to determine aneuploidy frequencies for chromosomes 1, 13, 18, 21, X, and Y in sperm from swim-up and pellet fractions.

Main Outcome Measure(s): Gametic aneuploidy was scored in sperm fractions separated by the swim-up …

Resurgence Of Sleeping Sickness In Tambura County, Sudan, Anne Moore, Michaleen Richer, Mario Enrile, Edward Losio, Jacquelin Roberts, Deborah A. Levy

Journal Articles: Epidemiology

Endemic foci of human African trypanosomiasis are present in southern Sudan. In 1996 and 1997, trypanosomiasis increased sharply in Tambura County. To define the magnitude and geographic distribution of the outbreak, we conducted a prevalence survey using population-based cluster sampling in 16 villages: 1,358 participants answered questions about routine activities and tsetse fly contact and received serologic testing. Seroprevalence in the surveyed area was 19.4% (95% confidence interval = 16.9%, 21.8%). We confirmed infection in 66% of seropositive persons who received one parasitologic examination and in 95% of those who had serial examinations of lymph node fluid and blood. Activities …

Posttransplant Recoarctation Of The Aorta: A Twelve Year Experience., Girish S. Shirali, C E. Cephus, M A. Kuhn, K K. Ogata, L K. Vander Dussen, R E. Chinnock, N F. Mulla, J K. Johnston, L L. Bailey, S R. Gundry, A J. Razzouk, R L. Larsen

Manuscripts, Articles, Book Chapters and Other Papers

OBJECTIVES: This study was undertaken to investigate the incidence of posttransplant recoarctation of the aorta, delineate the mode of presentation, identify risk factors that predict recoarctation and examine the results of intervention for posttransplant recoarctation.

BACKGROUND: Patients with aortic arch hypoplasia require extended arch reconstruction at transplant, with an inherent possibility of subsequent recoarctation of the aorta.

METHODS: This was a retrospective review of all children (ageyears) who underwent cardiac transplantation over a 10-year period. Collected data included pretransplant diagnosis, details of the transplant procedure and posttransplant data including development of recoarctation of the aorta, interventions for recoarctation and the …

Isolation Of Lautropia Mirabilis From Oral Cavities Of Human Immunodeficiency Virus-Infected Children, S. N. Rossmann, P. H. Wilson, J. Hicks, B. Carter, S. G. Cron, C. Simon, C. M. Flaitz, G. J. Demmler, W. T. Shearer, M. W. Kline

Faculty, Staff and Student Publications

Lautropia mirabilis, a pleomorphic, motile, gram-negative coccus, has been isolated from the oral cavities of 32 of 60 (53.3%) children infected with human immunodeficiency virus (HIV) and 3 of 25 (12.0%) HIV-uninfected controls; the association of L. mirabilis isolation with HIV infection is significant (P < 0.001). All children in the study, both HIV-infected children and controls, were born to HIV-infected mothers. The presence of this bacterium was not associated with clinical disease in these children. The HIV-infected children with L. mirabilis did not differ from the HIV-infected children without L. mirabilis in immunological status, clinical status, or systemic medications. The role of HIV infection itself or concomitant factors in the establishment of L. mirabilis in the oral cavity remains to be elucidated.

Treatment Of Nocturnal Enuresis In Four Male Adolescent Sex Offenders, Deloy Herman Johnson

Undergraduate Honors Capstone Projects

Over the three months of this study, the subjects were detained 24 hours per day, every day at a residential center for sex offenders. Of the four subjects, three received medications for nocturnal enuresis while the other one received medication for hyperactive behavior. The time interval between nocturnal events increased for the recipients of sensitivity training. This study was a three-month study without follow up. The increased interval may be explained by two other confounds that were not measured: 1) the clients who had the longer intervals at the end of the study were also on medication, which possibly contributed …

How Do Hmos Achieve Savings? The Effectiveness Of One Organization's Strategies., Ann B. Flood, Allen M. Fremont, K Jin, David M. Bott

Dartmouth Scholarship

To examine how a group practice used organizational strategies rather than provider-level incentives to achieve savings for health maintenance organization (HMO) compared to fee-for-service (FFS) patients. A large group practice with a group model HMO also treating FFS patients. Data sources were all patient encounter records, demographic files, and clinic records covering 3.5 years (1986-1989). The clinic's procedures to record services and charges were identical for FFS and HMO patients. All FFS and HMO patients under age 65 who received any outpatient services during approximately 100,000 episodes of the seven study illnesses were eligible.