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Biomedical subjects

J Anderson

Publications and source records attributed to J Anderson.

At least 235 records · Page 13Linked to original sources
PubMed1998

Options for liferaft entry after helicopter ditching.

METHOD: Dry and wet evacuations were conducted by 24 male and 19 female subjects from the Nutec Super Puma Simulator into two different types of aviation liferaft. RESULTS: Dry evacuation on the windward side is the method of choice. The non-canopy raft is subjectively and objectively easier to enter both from the helicopter and the sea. CONCLUSIONS: The non-canopy raft is the raft of choice, the canopy raft needs a redesign to ensure that it always inflates the correct way and both rafts need a redesign of the painter anchor point. Aircrew should have special training in open water after traditional pool training. A helicopter ditching survival compass has been developed for training all who fly over water for a living.

Accidents, Aviation↗
PubMed1998

Allogeneic bone marrow transplantation for myelodysplastic syndrome: outcomes analysis according to IPSS score.

The objective of our analysis was to determine the post-transplantation outcomes for patients with myelodysplastic syndrome (MDS) according to their International Prognostic Scoring System (IPSS) risk categorization. Data for all MDS patients transplanted at our institution from 1981-1996 were reviewed. Multivariate analysis was used to determine factors predictive for non-relapse mortality, relapse, and disease-free survival. A total of 251 MDS patients (median age = 38 years) were transplanted from 1981-1996. The overall disease-free survival rate was 40%, with an 18% relapse rate. Older age, increasing disease duration, mismatched donors, male gender, and therapy-related MDS were factors that significantly enhanced the likelihood of non-relapse mortality. Increasing disease duration, morphology, and cytogenetics were significant in predicting relapses. Increasing age, disease morphology, and cytogenetics were significant in determining disease-free survival. IPSS score was found to correlate significantly with relapse and disease-free survival. The 5-year disease-free survival was 60%, 36%, and 28% for low and intermediate-1 risk, intermediate-2 risk, and high risk patients, respectively. We conclude that IPSS score may be used to predict relapse and disease-free survival in MDS patients undergoing allogeneic transplantation. Allogeneic transplantation may be recommended for patients with intermediate-1, intermediate-2, or high risk MDS.

Adolescent↗
PubMed1998

Use of the WWW for distributed knowledge engineering for an EMR: the KnowledgeBank concept.

Developing automated tools for clinical information management requires an appreciation of user needs and capabilities. To address the reality of practice style variation, and the varying degree of comfort with computers in clinical users, we developed the KnowledgeBank concept. The KnowledgeBank concept includes an end-user authoring tool for clinical content in the EMR, and a web-based repository of content for sharing clinical content. We describe the early experiences of end-users using the KnowledgeBank.

Artificial Intelligence↗
PubMed1997

Immune versus natural selection: antibody aldolases with enzymic rates but broader scope.

Structural and mechanistic studies show that when the selection criteria of the immune system are changed, catalytic antibodies that have the efficiency of natural enzymes evolve, but the catalytic antibodies are much more accepting of a wide range of substrates. The catalytic antibodies were prepared by reactive immunization, a process whereby the selection criteria of the immune system are changed from simple binding to chemical reactivity. This process yielded aldolase catalytic antibodies that approximated the rate acceleration of the natural enzyme used in glycolysis. Unlike the natural enzyme, however, the antibody aldolases catalyzed a variety of aldol reactions and decarboxylations. The crystal structure of one of these antibodies identified the reactive lysine residue that was selected in the immunization process. This lysine is deeply buried in a hydrophobic pocket at the base of the binding site, thereby accounting for its perturbed pKa.

Animals↗
PubMed1997

Single trial variability within the P300 (250-500 ms) processing window in adolescents with attention deficit hyperactivity disorder.

The traditional averaging process used to derive event related potential components (ERPs) is a soundly based method of determining the underlying ERP. Averaging, however, ignores the variability due to the single-trial ERPs that constitute the traditional average ERP. This variability may reflect complementary functional information to the average measure. Our group applied a simple procedure, the response variance curve (RVC), which measures single-trial ERP variability relative to their average. In this study, the average ERP and RVC measures (generated from the same single-trial task-relevant target ERPs) were assessed in an auditory oddball paradigm, in 17 unmedicated male adolescents with attention deficit hyperactivity disorder (ADHD) and in 17 age- and sex-matched normal controls. P300 amplitude, latency and point of maximum variability of the RVC were measured within the P300 processing window (250-500 ms post-stimulus). There were no significant differences in P300 amplitude or latency between the groups. Unmedicated ADHD patients, however, showed significantly increased single-trial variability within the P300 window compared with controls. This variability was significantly reduced with stimulant medication.

Acoustic Stimulation↗
PubMed1997

The integrin-triggered rescue of T lymphocyte apoptosis is blocked in HIV-1-infected individuals.

HIV infection is associated with a disease status-dependent impairment of Ag-specific T cell responses, resulting in anergy or unchecked apoptotic cell death. beta1 integrins play an important role in the induction of T lymphocyte responses to antigenic challenge by providing a T cell costimulatory signal, and have been shown to rescue various cell types from undergoing apoptosis. We examined the integrin-triggered cell survival signal and associated pathways in CD3+ T cells derived from 69 HIV-1-infected individuals in comparison with healthy controls. We found beta1 integrin-mediated costimulation of TCR-induced T cell proliferation and protection from aberrant cell death to be absent in the majority of patients with AIDS, but intact in asymptomatic, infected individuals. The lack of integrin-mediated rescue may be partly due to an early impairment of TCR/integrin-costimulated secretion of IFN-gamma, a type 1 lymphokine that protects against TCR-induced apoptosis of T cells from HIV-seropositive donors, but not loss of integrin expression. The mechanism of integrin hyporesponsiveness appeared to correlate with a failure of the integrin-generated signal to induce pp125FAK mRNA and protein expression. Protein kinase C activation in CD3+ T cells following integrin stimulation was also impaired in HIV-infected individuals, mostly among the symptomatic/AIDS patients. Protein kinase C inactivation in T cells was shown to have a destabilizing effect in vitro on pp125FAK mRNA that contains an AUUUA motif in the 3'-untranslated region, a consensus sequence for the AU-rich elements responsible for mRNA destabilization. These aberrant changes in pp125FAK expression may have direct significance to the overall immunopathogenesis during infection with HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Cognitive impairment in geriatric chronic schizophrenic patients: a cross-national study in New York and London.

Severe cognitive impairment has been reported in large numbers of geriatric chronic schizophrenic patients in the US, with this impairment also being related to severe negative symptoms and adaptive deficits. It is not clear if this impairment is related to the particular environment of the American state hospitals and would not generalize to other countries. In this study, a sample composed of geriatric (age > 70) chronic schizophrenic patients in London, who were assessed by the Team for Assessment of Psychiatric Services (TAPS) (N = 137), and a group of geriatric chronic schizophrenic patients in a New York psychiatric center (N = 86) were compared for the severity of cognitive impairment and on measures of adaptive functioning. Patients received essentially identical Mini-Mental State Examination (MMSE) scores, but differed on 3/4 measures of adaptive functioning. The correlations among all four aspects of adaptive deficit and MMSE scores were very similar in the two samples, suggesting that cognitive deficits and their relationship with adaptive impairments are relatively invariant across different psychiatric systems of care, while adaptive functioning deficits are more variable and possibly more influenced by environmental factors. These data add to previous results suggesting that cognitive impairment is a common feature in poor outcome geriatric patients with schizophrenia.

Aged↗
PubMed1997

A prospective, longitudinal, multicenter study of service utilization and costs in fibromyalgia.

OBJECTIVE: To study, for the first time, service utilization and costs in fibromyalgia, a prevalent syndrome associated with high levels of pain, functional disability, and emotional distress. METHODS: Five hundred thirty-eight fibromyalgia patients from 6 rheumatology centers were enrolled in a 7-year prospective study of fibromyalgia outcome. Patients were assessed every 6 months with validated, mailed questionnaires which included questions regarding fibromyalgia symptoms and severity, utilization of services, and work disability. RESULTS: Fibromyalgia patients averaged almost 10 outpatient medical visits per year, and when nontraditional treatments were considered, this number increased to approximately 1 visit per month. Patients were hospitalized at a rate of 1 hospitalization every 3 years. In each 6-month study period, patients used a mean of 2.7 fibromyalgia-related drugs. Costs increased over the course of the study. The mean yearly per-patient cost in 1996 dollars was $2,274. However, results were skewed by high utilizers, and many patients used few services and had limited costs. Total costs and utilization were independently associated with the number of self-reported comorbid or associated conditions, functional disability, and global disease severity. Compared with patients with other rheumatic disorders, those with fibromyalgia were more likely to have lifetime surgical interventions, including back or neck surgery, appendectomy, carpal tunnel surgery, gynecologic surgery, abdominal surgery, and tonsillectomy, and were more likely than other rheumatic disease patients to report comorbid or associated conditions. Almost 50% of hospitalizations occurring during the study were related to fibromyalgia-associated symptoms. CONCLUSION: The average yearly cost for service utilization among fibromyalgia patients is $2,274. Fibromyalgia patients have high lifetime and current rates of utilization of all types of medical services. They report more symptoms and comorbid or associated conditions than patients with other rheumatic conditions, and symptom reporting is linked to service utilization and, to a lesser extent, functional disability and global disease severity.

Adult↗
PubMed1997

Health status and disease severity in fibromyalgia: results of a six-center longitudinal study.

OBJECTIVE: To determine the intermediate and long-term outcomes of fibromyalgia in patients seen in rheumatology centers in which there is special interest in the syndrome. METHODS: We conducted a longitudinal outcome study by mailed comprehensive Health Assessment Questionnaire administered every 6 months to 538 patients, from 6 rheumatology centers, whose median duration of disease at first assessment was 7.8 years. The final assessment took place after 7 years. In addition, there was study followup on 85 patients who had attended the Wichita center for > 10 years. RESULTS: Although functional disability worsened slightly and health satisfaction improved slightly, measures of pain, global severity, fatigue, sleep disturbance, anxiety, depression, and health status were markedly abnormal at study initiation and were essentially unchanged over the study period. Correlations between first and last assessment values were as high as r = 0.82. For some variables, abnormalities were 3 times greater at one center compared with another. CONCLUSION: Patients with established fibromyalgia, seen in rheumatology centers in which there a special interest in the disease and followed up for as long as 7 years, have markedly abnormal scores for pain, functional disability, fatigue, sleep disturbance, and psychological status, and these values do not change substantially over time. Half the patients are dissatisfied with their health, and 59% rate their health as fair or poor. There are marked differences in disease severity among the various centers, but < 14% of the variance in outcomes can be explained by demographic or center factors. Values at the first assessment are predictive of final values.

Cohort Studies↗
PubMed1997

Regulation of leukotriene and platelet-activating factor synthesis in human alveolar macrophages.

It has been suggested that phospholipase A2 (PLA2) contributes to the regulation of leukotriene (LT) and platelet-activating factor (PAF) synthesis by controlling the release of their precursors, arachidonic acid (AA) and lysophosphatidylcholine (lysoPC), from membrane phospholipids. In rat alveolar macrophages (AMs), PLA2 appears to have a major role in LT synthesis but a more limited role in PAF synthesis. The present study was designed to define the role of PLA2 in LT and PAF synthesis in human AMs and determine whether differences exist between AMs obtained from normal subjects and those from patients with asthma. In the normal subjects, the calcium ionophore A23187 (Cal) increased AM PAF synthesis (percent incorporation of tritiated acetate) by 135% (p < 0.01) and LTB4 synthesis 88-fold (p < 0.001). Phorbol myristate acetate (PMA) had little effect alone, but it had a synergistic effect with Cal, increasing PAF synthesis by 466% and LTB4 synthesis to 229-fold above the control values (p < 0.001 for both). Ro 25-4331, a combined cytosolic (c) and secretory (s) PLA2 inhibitor, had little effect on the Cal-stimulated PAF synthesis, but it completely blocked the effect of PMA. It also blocked the Cal- and Cal+PMA-stimulated LTB4 synthesis. AACOCF3, a cPLA2 inhibitor, had no effect on either Cal or Cal+PMA-stimulated PAF synthesis. It reduced LTB4 synthesis, but it did so less effectively than Ro 25-4331. CoA-independent transacylase (CoAI-TA) activity in the AMs increased after stimulation and exposure to Ro 25-4331. SK&F 45905, a CoAI-TA inhibitor, reduced stimulated PAF synthesis by 30% to 40%. Patients with asthma had similar results except that cPLA2 had a greater role in stimulated LTB4 synthesis. These data indicate that PLA2 plays a direct role in human AM LT synthesis; both the cytosolic and secretory forms contribute to LT synthesis; PLA2 appears to have a more limited role in PAF synthesis, although it mediates the synergistic effect of PMA, probably via sPLA2; and CoAI-TA contributes to PAF synthesis during PLA2 inhibition. With the exception of the greater role for cPLA2 in stimulated LTB4 synthesis in the patients with asthma, the contributions of PLA2 and CoAI-TA to AM LT and PAF synthesis appear to be similar in normal subjects and patients with asthma.

Acetyltransferases↗