Biomedical subjects

Andrew D Jones

Publications and source records attributed to Andrew D Jones.

7 recordsLinked to original sources

PubMed2006

Ethanol can contribute to energy and environmental goals.

To study the potential effects of increased biofuel use, we evaluated six representative analyses of fuel ethanol. Studies that reported negative net energy incorrectly ignored coproducts and used some obsolete data. All studies indicated that current corn ethanol technologies are much less petroleum-intensive than gasoline but have greenhouse gas emissions similar to those of gasoline. However, many important environmental effects of biofuel production are poorly understood. New metrics that measure specific resource inputs are developed, but further research into environmental metrics is needed. Nonetheless, it is already clear that large-scale use of ethanol for fuel will almost certainly require cellulosic technology.

Biotechnology↗

PubMed2006

J.R.'s Choices.

Explore the source record for details and available documents.

Financing, Personal↗

PubMed2006

"The sponge perineum:" an innovative method of teaching fourth-degree obstetric perineal laceration repair to family medicine residents.

BACKGROUND: Fourth-degree perineal lacerations are an uncommon, unpredictable injury that family physicians may face. METHODS: After a needs assessment and feasibility review, we developed goals, objectives, instructional tools, and a feedback survey for a curriculum using a novel model to simulate perineal laceration repair. RESULTS: Fifty-six learners evaluated the session, expressing increased confidence with perineal laceration repair, the usefulness of the model, and their desire to see it included in the Advanced Life Support in Obstetrics course. CONCLUSIONS: The "sponge perineum" is an inexpensive, effective tool to teach perineal laceration repair. Further study is needed with actual patient experiences.

Curriculum↗

PubMed2003

Surgical complications of bone marrow transplantation.

BACKGROUND: We wished to determine the type of diseases in patients who received bone marrow transplant (BMT) that potentially involve the general surgeon at our institution. METHODS: The records of 542 patients who underwent bone marrow transplant at Oregon Health and Sciences University between January 1990 and December 2000 were retrospectively reviewed. Gastrointestinal complications included in the study were gastrointestinal bleeding, venoocclusive disease of the liver, intestinal graft versus host disease, pneumatosis intestinalis, necrotizing enteritis, as well as other more common surgical diseases (eg, appendicitis). RESULTS: Gastrointestinal complications or surgical consultations were noted in 92 of 542 patients (17%). Of these, formal general surgical consultation was obtained in 48 patients (9%). The most common causes for surgical consult were cholecystitis (5), abdominal pain of unknown etiology (5), central line complications (5), small bowel obstruction (4), and appendicitis (4). Twenty-eight (58%) of these patients received an operation. Six patients (13%) died during the same hospitalization as their surgery consult. Forty-four patients with these gastrointestinal symptoms related to transplantation did not receive surgical consult. The mortality in this group was 45%. CONCLUSIONS: The majority of gastrointestinal complications after bone marrow transplant do not require surgical intervention. However, these conditions may overlap the more common reasons for surgical consult and must be identifiable by the general surgeon. Of patients who did require surgical intervention, it was primarily for common surgical diseases.

Adult↗

PubMed2003

Helicobacter pylori induces apoptosis in Barrett's-derived esophageal adenocarcinoma cells.

Helicobacter pylori may protect against the development of dysplasia in Barrett's epithelium of patients with gastroesophageal reflux disease. The aim of this study was to determine whether H. pylori preferentially induces apoptosis in Barrett's-derived cancer cells compared to normal cells. A Barrett's-derived adenocarcinoma cell line (OE33) was grown. H. pylori wild-type, isogenic vacA-, cagA(-), and picB-/cagE- mutant strains were grown on agar plates. Intact or sonicated bacteria were used to treat normal and OE33 cells for 24 hours, and Hoechst dye binding was performed to measure apoptosis. FAS protein expression was determined by Western immunoblotting. OE33 cells treated with intact H. pylori wild-type strains produced significant (P < 0.05) dose-dependent increases in apoptosis compared to normal esophageal cells. H. pylori wild-type and vacA- isogenic strains were more effective than cagA- and picB-/cage- isogenic strains in inducing apoptosis in OE33 cells. In OE33 cells, H. pylori sonicates produced lower levels of apoptosis than intact bacteria. Wild-type H. pylori strains increased Fas protein expression in OE33 cells at 18 hours. H. pylori induced apoptosis at a higher rate in the Barrett's-derived human esophageal adenocarcinoma cells than in normal esophageal cells. The H. pylori-induced apoptosis was primarily dependent on intact bacteria and the presence of the cagA and picB/cagE gene products. H. pylori-induced apoptosis may involve the Fas-caspase cascade.

Adenocarcinoma↗

PubMed2002

Mechanisms underlying dependencies of performance on stimulus history in a two-alternative forced-choice task.

In choice reaction time tasks, response times and error rates demonstrate differential dependencies on the identities of up to four stimuli preceding the current one. Although the general profile of reaction times and error rates, when plotted against the stimulus histories, may seem idiosyncratic, we show that it can result from simple underlying mechanisms that take account of the occurrence of stimulus repetitions and alternations. Employing a simple connectionist model of a two-alternative forced-choice task, we explored various combinations of repetition and alternation detection schemes in an attempt to account for empirical results from the literature and from our own studies. We found that certain combinations of the repetition and the alternation schemes provided good fits to the data, suggesting that simple mechanisms may serve to explain the complicated but highly reproducible higher order dependencies of task performance on stimulus history.

Adolescent↗

PubMed2002

A computational model of anterior cingulate function in speeded response tasks: effects of frequency, sequence, and conflict.

A growing body of evidence from functional neuroimaging and computational modeling studies indicates that the anterior cingulate cortex (ACC) detects the presence of response conflict and conveys this information to other brain regions, enabling subsequent adjustments in cognitive control. The present study examined previous empirical findings of increased ACC for low-frequency stimuli across three distinct speeded response tasks (two-alternative forced choice, go/no-go, and oddball). Simulations conducted in a neural network model incorporating sequential priming mechanisms (developed in Cho et al., 2002) confirmed that a computational measure of response conflict was higher on low-frequency trials across all three tasks. In addition, the model captured detailed aspects of behavioral reaction time and accuracy data, predicted the dynamics of ACC activity related to trial sequence effects, and provided evidence for the functional role of conflict information in performance monitoring and optimization. The results indicate that the conflict-monitoring hypothesis, augmented by mechanisms for encoding stimulus history, can explain key phenomena associated with performance in sequential speeded response tasks.

Adolescent↗