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Biomedical subjects

B A Moore

Publications and source records attributed to B A Moore.

At least 37 records · Page 2Linked to original sources
PubMed2000

Neural pathways regulating Brunner's gland secretion in guinea pig duodenum in vitro.

This study examined the neural pathways innervating Brunner's glands using a novel in vitro model of acinar secretion from Brunner's glands in submucosal preparations from the guinea pig duodenum. Neural pathways were activated by focal electrical stimulation and excitatory agonists, and videomicroscopy was used to monitor dilation of acinar lumen. Electrical stimulation of perivascular nerves evoked large dilations that were blocked by TTX (1 microM) or the muscarinic receptor antagonist 4-diphenylacetoxy-N-(2-chloroethyl)-piperidine hydrochloride (1 microM). The nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium iodide (100 microM) had no effect, and the nerve-evoked responses were not inhibited by hexamethonium (200 microM). Dilations were abolished in preparations from chronically vagotomized animals. Activation of submucosal ganglia significantly dilated submucosal arterioles but not Brunner's glands. Effects of electrical stimulation of perivascular and submucosal nerves were not altered by guanethidine. Capsaicin and substance P also dilated arterioles but had no effect on Brunner's glands. Cholinergic (choline acetyltransferase-immunoreactive) nerve fibers were found in Brunner's glands. These findings demonstrate that Brunner's glands are innervated by cholinergic vagal fibers but not by capsaicin-sensitive or intrinsic enteric nerves.

Animals↗
PubMed1999

ATF-1 is activated in response to UV irradiation in B16 melanoma cells.

We have found that the transferrin receptor gene promoter is strongly activated by exposure of B16 melanoma cells to UV light. This is a delayed event occurring more than 6 h after exposure and requires an AP-1/CRE-like element in the promoter as demonstrated by site-specific mutagenesis. UV irradiation enhances the binding of a nuclear factor to this element and supershift analysis demonstrates that this DNA-protein complex involves ATF-1. No other members of either the AP-1 or CREB/ATF families of transcription factors were found to bind to this DNA element in UV-irradiated B16 cells. Western blots show that the level of ATF-1 does not change following exposure to UV light, indicating that the increased binding of this factor is most likely mediated by posttranslational modifications in response to UV-mediated signaling pathways.

Activating Transcription Factor 1↗
PubMed1998

Dynamic changes in hypermnesia across early and late tests: a relational/item-specific account.

Two experiments tested predictions derived from R. R. Hunt and M. A. McDaniel's (1993) relational/item-specific account of hypermnesia. According to this framework, participants encoding relational information should show greater hypermnesia on early test trials than on later test trials. In contrast, participants encoding item-specific information should show greater hypermnesia on later test trials than on early test trials. These predictions were not anticipated by other accounts but were confirmed by the results. Further, the patterns of reminiscence and intertest forgetting supported the theoretical underpinnings of these predictions. A 3rd experiment examined some factors by which item-specific encoding might enhance reminiscence (and thus hypermnesia) on later test trials. These results suggested that a richer set of encoded attributes rather than a fluctuating retrieval plan supported the beneficial effects of item-specific encoding on reminiscence.

Female↗
PubMed1998

Organization of intrinsic cholinergic neurons projecting within submucosal plexus of guinea pig ileum.

Electrophysiological techniques were employed to examine the organization of the projections of submucosal neurons in the submucosal plexus of guinea pig ileum. These neurons were activated by focal pressure-pulse application of 5-hydroxytryptamine (5-HT) to single ganglia in submucosal preparations in vitro, and resulting fast excitatory postsynaptic potentials (EPSPs) were recorded intracellularly in S-type neurons. 5-HT-evoked fast EPSPs were blocked by TTX, hexamethonium, and ICS-205-930 (tropisetron). 5-HT was applied either directly to the ganglion containing the neuron recorded intracellularly or to adjacent ganglia positioned at increasing distances on either side of the impaled cell in circumferential or longitudinal orientations. All S-type neurons recorded in this study (n = 103) received nicotinic fast EPSPs from cholinergic neurons when 5-HT was applied directly to the ganglion containing the impaled neuron. Stimulation of adjacent ganglia also evoked nicotinic fast EPSPs, but the number of neurons that received this input decreased as the distance between the stimulus and the impaled cell increased. Maximal projections were 3 mm in the circumferential and orad-to-aborad orientations. There were no significant projections in the aborad-to-orad direction. These findings suggest that S-type neurons in the submucosal plexus are innervated by intrinsic cholinergic neurons that project over relatively short distances and have a distinct orad-to-aborad polarity.

Animals↗
PubMed1998

AIDS risk behavior in opioid dependent patients treated with community reinforcement approach and relationships with psychiatric disorders.

This study examined the Community Reinforcement Approach's (CRA) effect on AIDS risk behaviors and the relationship between comorbid psychiatric disorders and the risk for AIDS behavior in opioid dependent patients entering methadone maintenance treatment. Additionally, we looked at AIDS risk behaviors as they related to the Addition Severity Index (ASI), Beck Depression Inventory, Symptom Checklist-90-Revised (SCL-90-R), and the Social Adjustment Scale-Self Report (SAS-SR). Subjects (N = 227) were drawn from a large clinical trial that examined the effectiveness of a Community Reinforcement Approach for treatment of opioid dependence. Both CRA and standard treatment demonstrated a significant effect on reduction of AIDS risk behaviors. There was no relationship found regarding comorbid psychiatric disorders with the risk for AIDS behavior. However, there were correlations with other psychiatric, social, and substance abuse variables. Multivariate analyses indicated that increased drug and legal ASI composite scores were the primary predictors of increased AIDS risk behavior.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Community reinforcement approach in the treatment of opiate addicts.

The authors studied the efficacy of the community reinforcement approach (CRA) as compared to standard counseling in opiate-dependent patients on methadone maintenance. One hundred eighty subjects were randomized to three treatment conditions: standard, CRA, and CRA with relapse prevention (CRA/RP). Of these, 151 subjects were followed up 6 months after intake. Since few of the RP sessions had been concluded at the 6-month follow-up, the two CRA groups were combined for analyses. Weekly urinalysis drug screens and Addiction Severity Index (ASI) scores at intake and 6 months were compared. The combined CRA groups did significantly better than the standard group in the following areas: consecutive opiate-negative urinalysis (3 weeks), and the 6-month ASI drug composite score. These results support the benefit of adding CRA strategies to the treatment of patients who are opiate dependent and on methadone maintenance. Because of insufficient treatment exposure to RP at the 6-month follow-up, the additive effect of RP could not be adequately evaluated; further follow-up will be required.

Behavior Therapy↗
PubMed1997

Lower gastrointestinal bleeding.

BACKGROUND: Lower gastrointestinal bleeding can be a confusing clinical conundrum, the satisfactory evaluation and management of which requires a disciplined and orderly approach. Diagnosis and management has evolved with the development of new technology such as selective mesenteric angiography and colonoscopy. PURPOSE: This study was undertaken to review the available data in the literature and to determine the current optimum method of evaluation and management of lower gastrointestinal hemorrhage most likely to result in a successful outcome. METHODS: Data available on the topic of lower gastrointestinal bleeding in the English literature were obtained via MEDLINE search and were reviewed and analyzed. RESULTS: The colonic origin of lower gastrointestinal hemorrhage in order of decreasing incidence is diverticulosis, inflammatory bowel disease, including ischemic and infectious colitis, colonic neoplasia, benign anorectal disease, and arteriovenous malformations. Approximately 10 to 15 percent of all cases of rectal bleeding are attributable to a cause that is proximal to the ligament of Treitz. Small intestinal sources such as arteriovenous malformations, diverticula, and neoplasia account for between 3 and 5 percent of all cases. Colonoscopy successfully identified an origin in severe hematochezia in 74 to 82 percent of cases. Mesenteric angiography has a sensitivity of 42 to 86 percent. The best method of management depends on whether hemorrhage persists, the severity of continued hemorrhage, the cumulative transfusion requirement, and the specific origin of bleeding. CONCLUSION: Lower gastrointestinal hemorrhage is a complex clinical problem that requires disciplined and sophisticated evaluation for successful management. Diverticulosis is the most common cause. Colonoscopy is the diagnostic procedure of choice both for its accuracy in localization and its therapeutic capability. Selective mesenteric angiography should be reserved for those patients in whom colonoscopy is not practical. Precise identification of the bleeding source is crucial for a successful outcome. Specific directed therapy, such as segmental colonic resection for bleeding diverticulosis, is associated with the highest success rate and the lowest morbidity. A complete review of lower gastrointestinal bleeding is contained herein.

Angiography↗
PubMed1997

Emotion, motivation, and text comprehension: the detection of contradictions in passages.

The authors investigated the effects of experimentally induced mood states on the identification of contradictions in text passages and ratings of comprehension in 3 experiments. Mood impaired comprehension in college students across a variety of passages, as evidenced by a depressive impairment in contradiction identification and an increased number of false identifications among depressed participants. Additionally, depressed individuals were less accurate in their judgments of passage difficulty. These findings are consistent with the resource allocation model of mood effects, which attributes impaired comprehension to the activation of intrusive, irrelevant thoughts during reading of the passage. It is further argued that these results cannot be explained simply by a deficit in motivation of the depressed participants.

Adult↗
PubMed1997

Characterization of neurokinin-1 receptors in the submucosal plexus of guinea pig ileum.

This study combined immunohistochemical double-labeling techniques with functional studies to characterize the neurokinin-1 (NK1) receptors mediating neuronal and vasodilator responses in submucosal guinea pig ileum. NK1 receptor distribution in whole mount preparations of the submucosa was examined using a rabbit polyclonal antibody directed against the COOH terminus of the rat NK1 receptor. Results showed that 97% of neuropeptide Y immunoreactive submucosal neurons colocalized NK1 receptor immunoreactivity, whereas vasoactive intestinal polypeptide immunoreactive neurons were not NK1 immunoreactive. Intracellular recordings were made using neurobiotin-filled electrodes to enable reidentification of recorded neurons for immunohistochemical study. The selective NK1 agonists [Sar9,Met(O2)11]substance P (SP) and septide depolarized S-type submucosal neurons. Of these neurons, 36% were NK1 immunoreactive and 64% were not. NK1 immunoreactivity was not observed on submucosal arterioles, but superfusion of [Sar9,Met(O2)11]SP and septide dilated preconstricted submucosal arterioles. Agonist-evoked responses in both neurons and blood vessels were blocked by the selective NK1 antagonist CP-99994. These findings suggest that NK1 receptors are found on submucosal neurons and arterioles and that electrophysiological and immunohistochemical techniques may identify conformational variants of the receptor.

Animals↗
PubMed1996

Role of 5-HT in cholera toxin-induced mucin secretion in the rat small intestine.

We examined the role of 5-hydroxytryptamine (5-HT) in cholera toxin (CT)-induced mucin secretion in the proximal and distal regions of the rat small intestine. Neither the 5-HT2 receptor antagonist ketanserin nor the cyclooxygenase inhibitor indomethacin was capable of inhibiting choleraic mucin secretion. However, in the presence of the mixed 5-HT3/4 receptor antagonist tropisetron at doses that block both receptor subtypes, the secretory response was reduced to baseline levels in the proximal and distal small intestine. The selective 5-HT3 receptor antagonist ondansetron had no significant effect. These findings suggest that choleraic mucin secretion is mediated primarily through the activation of a 5-HT4-like receptor. Mucin secretion in response to the exogenous application of 5-HT occurs via two pathways: one is mediated by a 5-HT4-like receptor and is capsaicin sensitive but tetrodotoxin (TTX) insensitive, and one lacks the capsaicin-sensitive 5-HT4-mediated response but is TTX sensitive. Both converge on a common pathway that is cholinergic. No significant differences were observed between proximal and distal intestinal segments.

Animals↗
PubMed1993

Neural mediation of cholera toxin-induced mucin secretion in the rat small intestine.

We examined the role of enteric nerves in cholera toxin (CT)-induced mucin secretion in proximal and distal regions of rat small intestine. Stimulation of intestinal loops with 120 micrograms (1.5 mumol) CT using an in vitro open-loop model resulted in an approximately four-fold increase in luminal mucin content over unstimulated controls in both regions of the gut. Prior treatment of loops with tetrodotoxin had no effect on the amount of mucin released in response to CT. However, permanent destruction of primary sensory afferent nerves by neonatal treatment of rats with capsaicin reduced the mucin response to CT to baseline levels in both regions. In normal animals, atropine resulted in approximately 40% inhibition of mucin secretion in both the proximal and distal small intestine. The atropine-sensitive secretory response appears to be a component of the capsaicin-sensitive response. These results suggest that choleraic mucin secretion is mediated primarily by a capsaicin-sensitive neurogenic pathway involving local activation of sensory nerves, which may then elicit mucin secretion through interaction with cholinergic nerves.

Animals↗
PubMed1993

A stationary hemispherical SPECT imager for three-dimensional brain imaging.

A completely stationary, hemispherical-coded aperture SPECT imaging system was designed to produce three-dimensional images of the brain. The system consisted of a hemispherical multiple-pinhole coded aperture and 20 small (100 x 100 mm crystal area) digital gamma cameras. Reconstructions and measured performance specifications from two laboratory versions of the imager are presented. The reconstructed field of view of these systems was an ellipsoidal region with semi-diameters of 100 x 100 x 50 mm. The reconstructed spatial resolution for a point source in air at the center of this field was found to be 4.8 mm FWHM and the corresponding system sensitivity was 36 cps/microCi. An analysis using an ideal-observer model indicated that the multiplexed projection data suffered a 21% degradation relative to similar, but nonmultiplexed SPECT data. Therefore, by this measure, the effective sensitivity of the brain imager was 79% of the measured value.

Brain↗
PubMed1984

Anetoderma. Clinical findings, associations, and long-term follow-up evaluations.

In 16 patients with anetoderma, a clinicohistologic entity related to a local dermal defect of elastic tissue, old lesions did not heal, and new lesions often continued to form for many years, despite various forms of treatment. Systemic lupus erythematosus, which occurred in one patient, must be ruled out in patients with anetoderma. Discoid lupus erythematosus occurred later in one patient. Other associated findings, noted in one patient each, included cataract, congenital hip dislocation, congenital fusion of the vertebrae at C2-3, diverticulum of the midesophagus, Addison's disease (before the onset of anetoderma), and mitral valve prolapse. Our results and a review of the literature indicate that patients with anetoderma must be examined for associated eye, bone, heart, pulmonary, digestive tract, and endocrine abnormalities for a better assessment of their skin disorders.

Adolescent↗
PubMed1984

Ultrastructural findings in the skin lesions of patients with anetoderma.

Eight biopsy specimens from the skin lesions of five patients with anetoderma were studied for their ultrastructural findings. In all of them, normal elastic fibers were absent and a few very thin, irregular elastic fibers with a more or less complete loss of the amorphous substance and a relative conservation of the microfibrils were observed. The collagen fibers were normal. Inflammation composed of macrophages and lymphocytes, with some plasma cells, was a prominent finding. It is suggested that anetoderma and acquired cutis laxa are part of the same spectrum of elastolytic disease.

Adolescent↗
PubMed1981

6 beta-Iodopenicillanic acid (UI-38,006), a beta-lactamase inhibitor that extends the antibacterial spectrum of beta-lactam compounds: initial bacteriological characterization.

UK-38,006, 6 beta-iodopenicillanic acid, was shown to be a potent inhibitor of beta-lactamase enzymes. It potentiated the antibacterial action of ampicillin in vitro against beta-lactamase-producing strains of Staphylococcus aureus, Haemophilus influenzae, Bacteroides fragilis. Neisseria gonorrhoeae, and many Enterobacteriaceae. This ability to synergize with ampicillin was also demonstrated in vivo after oral administration of UK-38,006 to experimentally infected mice. UK-38,006 was also shown to synergize in vitro with other penicillins and cephalosporins against beta-lactamase-producing strains of Escherichia coli, Proteus mirabilis, and Klebsiella species.

Ampicillin↗
PubMed1979

Peptidoglycan transpeptidase inhibition in Pseudomonas aeruginosa and Escherichia coli by Penicillins and Cephalosporins.

Peptidoglycan transpeptidase activity has been studied in cells of Escherichia coli 146 and Pseudomonas aeruginosa 56 made permeable to exogenous, nucleotide-sugar peptidoglycan precursors by ether treatment. Transpeptidase activity was inhibited, in both organisms, by a range of penicillins and cephalosporins, the Pseudomonas enzyme being more sensitive to inhibition in each case. Conversely, growth of E. coli 146 was more susceptible to these antibiotics than growth of P. aeruginosa 56. Furthermore, similar transpeptidase inhibition values were ob-obtained for the four penicillins examined against the Pseudomonas enzyme, although only two of these (carbenicillin and pirbenicillin) inhibited the growth of this organism. We therefore conclude that the high resistance of P. aeruginosa 56 to growth inhibition by most beta-lactam antibiotics cannot be due to an insensitive peptidoglycan transpeptidase.

Acyltransferases↗