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Biomedical subjects

B D Smith

Publications and source records attributed to B D Smith.

At least 37 records · Page 2Linked to original sources
PubMed2001

Hemispheric specialization in emotion: attention, arousal, and EEG activation in unilateral temporal lobe epilepsy.

To investigate the neural processing of emotion in right and left temporal lobe epilepsy (TLE), we monitored EEG during neutral and emotionally positive and negative auditory stimulation. Left TLE patients displayed increased right lateralization and a negative emotional stimulus rating bias, while right TLE patients did not. This EEG arousal and negative affect may reflect deactivated inhibition of the right hemisphere, symptomatically expressed as arousal and anxiety. Failure to increase lateralization to emotional stimuli in right TLE may reflect compromised emotional attention/arousal centers in the right hemisphere. Results support a two-dimensional theory of the neural processing of emotion.

Acoustic Stimulation↗
PubMed2001

Molecular marker expression in oral and oropharyngeal squamous cell carcinoma.

OBJECTIVE: To determine the relative prognostic value of p53, cyclin D1, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) expression in patients with oral and oropharyngeal squamous cell carcinoma. DESIGN: Retrospective cohort study. PATIENTS: Fifty-six patients with oral and oropharyngeal squamous cell carcinoma referred to the Department of Therapeutic Radiology at Yale-New Haven Hospital (Conn) between 1981 and 1992 who were treated with gross total surgical resection and postoperative external beam radiotherapy. RESULTS: Archival tumor tissue was stained with monoclonal antibodies directed against these 4 oncoproteins and scored for staining intensity and percent distribution by a pathologist blinded to the patients' clinical outcomes. Frequency of marker expression was 48% for p53, 20% for cyclin D1, 64% for EGFR, and 41% for VEGF. In multivariate analysis, EGFR positivity was protective against locoregional relapse (relative risk [RR], 0.27; 95% confidence interval [CI], 0.11-0.66; P =.002). In contrast, advanced N stage predicted poor locoregional relapse-free survival (RR, 1.94; 95% CI, 1.03-3.66; P =.04). Predictors of poor overall survival in multivariate analysis included VEGF positivity (RR, 3.53; 95% CI, 1.75-7.13; P<.001) and black race (RR, 2.48; 95% CI, 1.05-5.85; P =.04). Cyclin D1 and p53 expression were not significantly associated with prognosis in this cohort. CONCLUSIONS: In oral and oropharyngeal squamous cell carcinoma treated with surgery and postoperative radiotherapy, VEGF and EGFR expression may influence clinical outcome. If confirmed, these results have potential implications for the determination of patient prognosis and the development of biologically based pharmacotherapies.

Adult↗
PubMed2000

Activase region on chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase. Nonconservative substitution in the large subunit alters species specificity of protein interaction.

In the active form of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC ), a carbamate at lysine 201 binds Mg(2+), which then interacts with the carboxylation transition state. Rubisco activase facilitates this spontaneous carbamylation/metal-binding process by removing phosphorylated inhibitors from the Rubisco active site. Activase from Solanaceae plants (e.g. tobacco) fails to activate Rubisco from non-Solanaceae plants (e.g. spinach and Chlamydomonas reinhardtii), and non-Solanaceae activase fails to activate Solanaceae Rubisco. Directed mutagenesis and chloroplast transformation previously showed that a proline 89 to arginine substitution on the surface of the large subunit of Chlamydomonas Rubisco switched its specificity from non-Solanaceae to Solanaceae activase activation. To define the size and function of this putative activase binding region, substitutions were created at positions flanking residue 89. As in the past, these substitutions changed the identities of Chlamydomonas residues to those of tobacco. Whereas an aspartate 86 to arginine substitution had little effect, aspartate 94 to lysine Rubisco was only partially activated by spinach activase but now fully activated by tobacco activase. In an attempt to eliminate the activase/Rubisco interaction, proline 89 was changed to alanine, which is not present in either non-Solanaceae or Solanaceae Rubisco. This substitution also caused reversal of activase specificity, indicating that amino acid identity alone does not determine the specificity of the interaction.

Animals↗
PubMed2000

Transgenic mice with a mutated collagen promoter display normal response during bleomycin-induced fibrosis and possess neurological abnormalities.

We have previously identified a potential TGF-beta activation element (TAE) in the rat collagen alpha1(I) promoter at -1624 upstream of the transcriptional start site [Ritzenthaler et al., 1991, 1993]. To determine the importance of the TAE in vivo, we produced transgenic mice carrying 3.6 kb of the rat collagen alpha1(I) promoter linked to the reporter gene chloramphenicol acetyl transferase with and without site-directed mutations that eliminate DNA-protein binding at the TAE site. Tissue-specific expression of the reporter gene in transgenic mice with the mutated collagen promoter was similar to that of transgenic mice with the normal promoter in two genetic backgrounds as judged by in situ hybridization, reporter assays, and immunochemistry. Endotracheal instillation of bleomycin induces lung fibrosis, mediated in part by TGF-beta. Earlier studies indicated that expression of wild-type collagen-reporter gene was upregulated in transgenic mice lungs in response to endotracheal instillation of bleomycin. A similar level of reporter gene upregulation was observed in transgenic mice carrying the mutation in the TAE. Two lines of transgenic mice carrying the mutated promoter construct displayed unexpected neurological abnormalities. In the FVB genetic background, there was a higher than normal incidence of mortality, spontaneous seizures, and an inability to nurture offspring. Histological evidence demonstrated clear abnormalities, including disorderly arrangement of neurons in the hippocampus and significant laminar cortical necrosis in the cerebrum in animals after seizures. In the C57Bl/6 background, there was a high incidence of severe communicating hydrocephalus, early runting, and increased mortality similar to that in transgenic animals with astroglial overexpression of TGF-beta. These animals provide an interesting model system to investigate molecular mechanisms responsible for seizures and hydrocephalus.

Animals↗
PubMed2000

Trait anxiety and prior exposure to non-stressful stimuli: effects on psychophysiological arousal and anxiety.

Arousal and anxiety responses to stressful stimulation are products of multiple factors that may include the physiological, behavioral, cognitive, affective, trait, and state components of our six-system model, as well as mediational and non-mediational perspectives. Within the context of this model, the present experiment examined the effects of prior exposure to neutral stimuli on arousal and anxiety responses to stress. High and low trait-anxious participants were randomly assigned to one of three prior exposure conditions in which they were exposed to stressful stimuli following exposure to: (a) neutral, non-stressful stimulation in the same modality (the Intramodality Prior Exposure or IPE experimental condition); (b) neutral stimuli in a different modality (the Cross-modality Prior Exposure or CPE control condition); or (c) a rest period (the Stress Only or SO control condition). Results showed that low trait anxious subjects had consistently larger arousal and anxiety responses to stress than did highs and that prior exposure to certain same-modality neutral stimuli reduced responses to subsequent stressors. In addition, arousal was greater in response to cognitive than to affective and in response to non-mediational than mediational conditions. Results are discussed in terms of the inverted-U arousal function and of the six-system model and its implications for understanding anxiety and arousal.

Acoustic Stimulation↗
PubMed2000

BP1, a new homeobox gene, is frequently expressed in acute leukemias.

Aberrant expression of homeobox genes has been described in primary leukemia blasts. We recently cloned a new cDNA, BP1, which is a member of the homeobox gene family. BP1 expression was investigated in bone marrow samples from acute myeloid leukemia (AML), acute T cell lymphocytic leukemia (ALL) and pre-B cell ALL. Expression levels of two apparent isoforms of BP1, DLX7 and DLX4, were measured in the same samples. They are weakly if at all detectable in normal bone marrow, PHA-stimulated T cells or B cells. BP1 RNA was highly expressed in 63% of AML cases, including 81% of the pediatric and 47% of the adult cases, and in 32% of T-ALL cases, but was not found in any of the pre-B ALL cases. Coexpression of BP1, DLX7 and DLX4 occurred in a significant number of leukemias. Our data, including co-expression of BP1 with c-myb and GATA-1, markers of early progenitors, suggest that BP1 expression occurs in primitive cells in AML. Analysis of CD34+ and CD34- normal bone marrow cells revealed BP1 is expressed in CD34- cells and virtually extinguished in CD34+ cells. Ectopic expression of BP1 in the leukemia cell line K562 increased clonogenicity, consistent with a role for BP1 in leukemogenesis. The presence of BP1 RNA in leukemic blasts may therefore be a molecular marker for primitive cells and/or may indicate that BP1 is an important upstream factor in an oncogenic pathway.

Acute Disease↗
PubMed2000

Increasing access and providing social services to improve drug abuse treatment for women with children.

AIMS: To assess the impact of a substance abuse treatment program for women with children designed to increase access to treatment through transportation, outreach and child-care services. Also, to assess the impact of using access services on the use of other services and on treatment effectiveness. DESIGN: A quasi-experimental non-equivalent control group design was used with path analysis to examine the impact of participation in an enhanced services program that provided transportation, outreach and child-care services on the use of other social services and on the use of alcohol and illicit drugs. SETTING: Treatment clients were interviewed in-person at enhanced treatment programs and regular substance abuse programs. PARTICIPANTS: Study participants included a randomly selected sample of women with children who were clients of the Illinois Department of Children and Family Services. Participants were enrolled in enhanced or regular substance abuse treatment programs. MEASUREMENTS: Study participants completed in-person interviews about their characteristics, services use and past and current substance use. FINDINGS: Participation in the enhanced program was negatively related to substance use. Further, use of access services was related to use of social services which in turn, was negatively related to substance use. CONCLUSION: The study indicates that services that enhance access to treatment and respond to the range of social service needs of women are important for effective substance abuse treatment for women with children.

Adult↗
PubMed2000

Prognostic significance of vascular endothelial growth factor protein levels in oral and oropharyngeal squamous cell carcinoma.

PURPOSE: Vascular Endothelial Growth Factor (VEGF) promotes angiogenesis in many different tumor types. VEGF levels may affect tumor growth, metastatic potential, and response to radiotherapy. This study assesses the prognostic value of VEGF protein levels in a cohort of patients with oral and oropharyngeal squamous cell carcinomas. The relationships between clinical outcome and the covariables of tumor-node-metastasis stage, disease stage (I to IV), grade, margin status, race, sex, and age were also determined. PATIENTS AND METHODS: Chart review identified 77 patients with oral or oropharyngeal squamous cell carcinoma treated with gross total surgical resection and postoperative radiation between 1981 and 1992. Sufficient follow-up data and tumor tissue were available in 56 patients (73%). VEGF protein levels were determined using immunohistochemistry. The association between VEGF status, covariables, and outcome was assessed in a bivariate and multivariate model using two-sided statistical tests. RESULTS: Twenty-three tumors (41%) were positive for VEGF expression. VEGF-positive tumors were more likely to recur locally (relative risk [RR] = 3.08; 95% confidence interval [CI], 1.03 to 9.24) and distantly (RR = 4.62; 95% CI, 1.41 to 15.10). In bivariate analysis, VEGF positivity was the most significant predictor of poor disease-free survival (RR = 2.66; 95% CI, 1.27 to 5.56) and overall survival (RR = 3.21; 95% CI, 1.63 to 6.32). In multivariate analysis, VEGF positivity was the most significant predictor of poor disease-free survival (RR = 2.75; 95% CI, 1.30 to 5.79) and overall survival (RR = 3.53; 95% CI, 1.75 to 7.13). CONCLUSION: In this cohort, VEGF positivity was the most significant predictor of poor prognosis. VEGF status may prove to be an important prognostic factor in head and neck cancer.

Adult↗
PubMed2000

Heuristic comparison of sertraline with nortriptyline for the treatment of depression in frail elderly patients.

Studies have demonstrated that the selective serotonin reuptake inhibitor antidepressants have similar efficacy to other agents, such as tricyclic antidepressants. However, data are limited for direct comparisons with other antidepressants. The authors conducted a contemporaneous comparison of nursing home residents treated with open-label sertraline in doses up to 100 mg/day with nursing home residents treated in a double-blind randomized study of low vs. regular doses of nortriptyline. There were 97 patients enrolled in the study (28 treated with sertraline), with an average treatment duration of 55 days. There were no differences in the tolerability of sertraline vs. nortriptyline. However, in this group of frail older adults, sertraline was not as effective as nortriptyline for the treatment of depression.

Aged↗
PubMed2000

Drug treatment of depression in frail elderly nursing home residents.

The authors conducted a randomized, double-blind, 10-week clinical trial of two doses of nortriptyline in eight nursing homes. Sixty-nine patients, average age 79.5 years, were randomized to receive regular doses (60 mg-80 mg/day) vs. low doses (10 mg-13 mg/day) of nortriptyline. Among the more cognitively intact patients, there was a significant quadratic relationship defining a "therapeutic window" for nortriptyline plasma levels and clinical improvement. There were also significant differences in plasma level-response relationships between depressed patients who were cognitively impaired and those who were more cognitively intact. Depression remains a syndrome that responds to specific treatment, even in frail nursing home patients, and those depressions that occur in patients with significant dementia may represent a treatment-relevant condition with a different plasma level-response relationship than in depression alone.

Aged↗
PubMed2000

Universal newborn hearing screening.

BACKGROUND: New technology has made universal newborn hearing screening possible. Our goal was to investigate the feasibility of universal newborn screening using distortion product otoacoustic emissions (DPOAE) on infants in a community hospital in a normal newborn nursery. METHODS: We used DPOAE to screen newborn infants from February 1997 to March 1999. RESULTS: Of 1002 infants, 111 failed the initial screen (11.1%). When screening was repeated, only 2 infants failed. One infant failed the second screen and a tympanogram. He was treated and he passed a third use of DPOAE. An additional infant failed the repeat screen but passed the tympanogram. That infant was referred on for auditory brain response testing. CONCLUSIONS: DPOAE testing can be accomplished easily in a normal newborn nursery with an acceptable false-positive rate when a two-stage approach is used. The cost for each test was $19.88. The cost to find the 1 infant with sensory neural hearing loss was $22,114.

Acoustic Impedance Tests↗
PubMed2000

E-cadherin expression is silenced by 5' CpG island methylation in acute leukemia.

E-Cadherin is a transmembrane glycoprotein that mediates Ca2+-dependent intercellular adhesion in normal epithelium. In tumors of epithelial origin, E-cadherin expression frequently is reduced, an event that contributes to tumor invasion and metastasis. The role of E-cadherin in hematopoietic tissues is less clear. In normal bone marrow, E-cadherin is expressed on erythroid progenitors, CD34+ stem cells, and stromal cells, where it likely contributes to intercellular interactions during hematopoiesis. In this study, we used a nested-PCR approach to examine the methylation status of the E-cadherin 5' CpG island in blood and bone marrow samples from normal donors and in bone marrow from patients with acute leukemia. In normal peripheral blood mononuclear cells and bone marrow, E-cadherin was completely unmethylated. In peripheral blood mononuclear cells, expression was evident by reverse transcription-PCR. Immunoblotting confirmed E-cadherin protein expression in two lymphoblastoid cell lines derived from normal donors. In contrast, E-cadherin was aberrantly methylated in 4 of 4 (100%) leukemia cell lines, 14 of 44 (32%) acute myelogenous leukemias, and 18 of 33 (53%) acute lymphoblastic leukemias. Genomic bisulfite sequencing of primary leukemias confirmed dense methylation across the CpG island. Methylation was associated with loss of E-cadherin RNA and protein in leukemia cell lines and primary leukemias. Following treatment with 5-aza-2'-deoxycytidine, a methylated leukemia cell line expressed both E-cadherin transcript and protein. Our results show that methylation of E-cadherin occurs commonly in acute leukemia and suggests a hypothesis for E-cadherin down-regulation in leukemogenesis.

Cadherins↗
PubMed1999

A methylation-responsive MDBP/RFX site is in the first exon of the collagen alpha2(I) promoter.

DNA methylation inhibits transcription driven by the collagen alpha2(I) promoter and the 5' end of the gene in transient transfection and in vitro transcription assays. DNA-binding proteins in a unique family of ubiquitously expressed proteins, methylated DNA-binding protein (MDBP)/regulatory factor for X box (RFX), form specific complexes with a sequence overlapping the transcription start site of the collagen alpha2(I) gene. Complex formation increased when the CpG site at +7 base pairs from the transcription start site was methylated. The identity of the protein was demonstrated by co-migration and cross-competition for a characteristic slowly migrating doublet complex formed on MDBP/RFX recognition sequences and the collagen sequences by band shift assays. A RFX1-specific antibody supershifted the collagen DNA-protein complexes. Furthermore, in vitro translated RFX1 protein formed a specific complex with the collagen sequence that was also supershifted with the RFX1 antibody. MDBP/RFX displayed a higher affinity binding to the collagen sequence if the CpG at +7 was mutated in a manner similar to TpG. This same mutation within reporter constructs inhibited transcription in transfection and in vitro transcription assay. These results support the hypothesis that DNA methylation-induced inactivation of collagen alpha2(I) gene transcription is mediated, in part, by increased binding of MDBP/RFX to the first exon in response to methylation in this region.

Animals↗
PubMed1999

Molecular markers as prognostic factors for local recurrence and radioresistance in head and neck squamous cell carcinoma.

Squamous cell carcinoma of the head and neck affects more than 500,000 people worldwide each year. Local-regional recurrence of disease is a common and challenging oncological problem in patients affected by this disease. Identification of risk factors for local relapse after appropriate local therapy with surgery, radiation, or combination therapy remains an active area of clinical research. The recent development of novel molecular markers has resulted in numerous studies evaluating the prognostic significance and potential clinical utility of these markers in identifying patients at risk for local-regional relapse. This article reviews recent studies evaluating molecular markers, including p53, angiogenesis-related markers, cyclin D1, epidermal growth factor receptor, loss of heterozygosity, DNA ploidy, and cell kinetic markers. The potential clinical utility of these markers and future directions along this avenue of investigation are discussed.

Biomarkers, Tumor↗
PubMed1999

Anxiety and arousal: tests of a new six-system model.

The present experiment was a test of a new six-system model of anxiety, which includes physiological, behavioral, cognitive, affective, trait, and state components of anxiety and also differentiates between direct and mediated responses. The State-Trait Anxiety Inventory was used to screen 795 undergraduates at the University of Maryland. Of the 52 subjects chosen, half were high trait anxious and half low. The two groups were further divided into high and low situational stress conditions. Subjects in the high-stress condition were exposed to two types of stressful cognitive and two types of stressful affective tasks. Subjects in the low-stress condition were exposed to the same four tasks with the stressful aspect removed. Prior state anxiety and cognitive or affective sensitivity were also considered. It was found that the most influential factor in resultant arousal was situational stress. Trait anxiety, state anxiety, and cognitive vs. affective sensitivity also significantly influenced both direct and mediated physiological and subjective anxiety responses. In addition, rather than leading to increased arousal, as hypothesized, the presence of trait and state anxiety reduced arousal under certain conditions.

Adult↗
PubMed1999

Philadelphia chromosome-negative engraftment after autologous transplantation with granulocyte-macrophage colony-stimulating factor for chronic myeloid leukemia.

Autologous bone marrow transplantation (BMT) has not been curative in chronic myeloid leukemia (CML), because of the inability to purge CML from the autograft and the absence of the allogeneic T cell-mediated antileukemic activity. However, recent advances demonstrate that normal progenitors can be selected from CML marrows by a variety of techniques, including isolation by their small size. Furthermore, we found that myeloid growth factors have a potent antileukemic effect against CML progenitors in vitro by inducing their terminal differentiation. Based on these data, we initiated a trial of autologous BMT in patients with high-risk CML. Autografts were processed in an attempt to enrich for normal progenitors, first by isolating small cells by counterflow centrifugal elutriation and then incubating them in granulocyte-macrophage colony-stimulating factor (GM-CSF) for 72 hours. After a conditioning regimen of busulfan and cyclophosphamide, all patients received GM-CSF daily for 2 months. The median age of the 13 patients in the trial was 45 years (range 17-56 years). The median duration of disease before BMT was 24 months (range 13-72 months). Eight patients were in chronic phase (CP), and five were in accelerated phase (AP). All patients failed to achieve a cytogenetic response to interferon-alpha and were 100% Philadelphia chromosome (Ph)+ before BMT. There were three transplant-related deaths, all AP patients. All of the remaining 10 patients engrafted with some degree of Ph- hematopoiesis; despite high-risk features, nine patients engrafted 100% Ph-. All patients relapsed cytogenetically at a median of 6 months (range 4-22 months). These results demonstrate that autologous BMT can consistently induce complete Ph- engraftment in CP patients. GM-CSF appears to produce a clinical antileukemic effect against CML after autologous BMT.

Adolescent↗
PubMed1999

The New Hampshire Perinatal Program: twenty years of perinatal outreach education.

OBJECTIVE: To describe 20 years of regional outreach education by the New Hampshire Perinatal Program, its interaction with all 26 community hospitals in the state with maternity services and an additional four in adjoining Vermont. STUDY DESIGN: This paper describes educational initiatives responsive to the needs of perinatal physicians and nurses. The core of the program is the transport conference held annually at each referring hospital in which maternal-fetal and infant referrals are discussed. There are additional community hospital-based programs, programs at convenient locations in the region and medical center conferences and skills programs. RESULTS: The program annually awards 10,000 continuing medical education credits (CME) and nursing contact hours. Evaluation and feedback from all participants is encouraged. New Hampshire has one of the lowest perinatal mortality rates in the county, which reflects in part the accomplishments of the program. CONCLUSION: Perinatal outreach education is a shared responsibility of providers in both the academic center and community hospitals and is necessary to ensure optimal care for mothers and infants.

Community-Institutional Relations↗