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Biomedical subjects

L Matheson

Publications and source records attributed to L Matheson.

13 recordsLinked to original sources
PubMed2005

Retroviral vector production in the National Gene Vector Laboratory at Indiana University.

The National Gene Vector Laboratory (NGVL) is a US National Institutes of Health initiative charged with providing clinical grade vectors for gene therapy trials. The program was started in 1995 and Indiana University has served as the production site for retroviral vectors and is also accepting applications for production of lentiviral vectors. The facility is designed to produce vectors for Phase I and Phase II clinical trials with the specific mandate to facilitate investigator-initiated research for academic institutions. To date, the facility has generated over 30 Master Cell Banks for gene therapy investigators throughout the United States. This required the facility to develop a system that can adapt to the varied needs of investigators, most of whom request different vector backbones, packaging cell lines, final product volumes, and media. In this review, we will illustrate some of the experiences of the Indiana University NGVL during the generation of retroviral vectors using murine-based packaging cell lines.

Animals↗
PubMed2001

Assessment of near-infrared spectral information for rapid monitoring of bioprocess quality.

Access to real-time process information is desirable for consistent and efficient operation of bioprocesses. Near-infrared spectroscopy (NIRS) is known to have potential for providing real-time information on the quantitative levels of important bioprocess variables. However, given the fact that a typical NIR spectrum encompasses information regarding almost all the constituents of the sample matrix, there are few case studies that have investigated the spectral details for applications in bioprocess quality assessment or qualitative bioprocess monitoring. Such information would be invaluable in providing operator-level assistance on the progress of a bioprocess in industrial-scale productions. We investigated this aspect and report the results of our investigation. Near-infrared spectral information derived from scanning unprocessed culture fluid (broth) samples from a complex antibiotic production process was assessed for a data set that incorporated bioprocess variations. Principal component analysis was applied to the spectral data and the loadings and scores of the principal components studied. Changes in the spectral information that corresponded to variations in the bioprocess could be deciphered. Despite the complexity of the matrix, near-infrared spectra of the culture broth are shown to have valuable information that can be deconvoluted with the help of factor analysis techniques such as principal component analysis (PCA). Although complex to interpret, the loadings and score plots are shown to offer potential in process diagnosis that could be of value in the rapid assessment of process quality, and in data assessment prior to quantitative model development.

Anti-Bacterial Agents↗
PubMed2000

At-line monitoring of a submerged filamentous bacterial cultivation using near-infrared spectroscopy.

The use of near infra-red spectroscopy (NIRS) to monitor a submerged filamentous bacterial bioprocess was investigated. An industrial strain of the filamentous bacterium Streptomyces fradiae was cultured in a 12 litre stirred tank reactor (STR) using a complex medium. This mycelial 4 phase (oil, water, gas and solid) system produced highly complex and variable matrices, therefore monitoring such a complex fluid with NIRS represented a considerable challenge. Nevertheless, successful models for four key analytes (methyl oleate, glucose, glutamate and ammonium) were built at-line (rapid off-line) using NIRS. In the present study, the methods used to formulate, select and validate the models for the key analytes are discussed, with particular emphasis on how the model performance can be critically evaluated. Since previous reports on NIRS in monitoring bioprocesses have either involved simpler matrices, or, in filamentous systems, have not discussed how NIRS models can be critically assessed, the emphasis in the present study on providing an insight into the modelling process in such a complex matrix, may be particularly important to the applicability of NIRS to such industrial bioprocesses.

Journal Article↗
PubMed2000

Informed consent and truth-telling: cultural directions for healthcare providers.

As the United States becomes more diverse in the healthcare beliefs and practices of its residents, delivery of culturally competent healthcare in an ethical manner becomes increasingly complex. Nurse administrators, who are responsible for interpreting policy and organizational expectations to their employees as well as ensuring that providers maintain the American Nurses Association's code of ethics, are challenged when providing care for diverse populations. Critical to providing culturally sensitive care is an understanding of different approaches to truth-telling. The authors present Korean, Southeast Asian, and First Nations (American Indian) case studies illustrating concepts of truth-telling and informed consent related to issues that arise when group-oriented persons or families respond to their health-care providers' actions.

Aged↗
PubMed1997

Dust mite allergen avoidance in the treatment of hospitalized children with asthma.

BACKGROUND: Asthma is a leading cause of hospital admission in children. The majority of children with asthma are sensitized and exposed to inhalant allergens that may contribute to chronic airway inflammation. OBJECTIVE: To evaluate the practicality and effects of dust mite (D. farinae and D. pteronyssinus) allergen avoidance in homes of children hospitalized with acute asthma. METHODS: Children 5 to 18 years of age who were admitted with asthma to a suburban Atlanta hospital were randomly assigned, without knowledge of allergen sensitization or exposure in their houses, to active (n = 13) or placebo (n = 10) treatment group. Active treatment included encasing mattress, box springs, and pillows in allergen impermeable covers; weekly hot water wash of bed linens; replacement of bedroom carpet with polished flooring; and 3% tannic acid spray to living room carpet. Placebo treatment included permeable encasing for bedding, cold water wash, and water spray for carpet. Dust samples were analyzed for dust mite, cockroach, and cat allergens, while serum samples were analyzed for IgE antibodies to the same allergens. Outcome measures included daily peak expiratory flow rates, spirometry, methacholine inhalation challenge, and hospital readmission. RESULTS: Children in both groups were similar by demographics, sensitization, and exposure to dust mite allergen. Allergen levels fell > 3-fold in many active and placebo homes. Children in the active group had improved PEFR at 3 and 6 months after intervention (P < .04, P < .05, respectively). Six of seven children in the study who were sensitized and exposed to dust mite allergen demonstrated improved PEFR at 3 months when allergen levels fell in both bedding and bedroom floor. There was no difference in FEV1 or methacholine challenge, although a few children in either group could tolerate methacholine because of bronchial hyperreactivity. Six children (four active and two placebo) were readmitted to hospital during the study. CONCLUSION: Increases in PEFR were recorded among children in the active treatment group and also among sensitized patients whose dust mite allergens fell. These results support the hypothesis that avoidance can be effective even among children admitted to hospital. The study was complicated by insufficient numbers of mite-allergic children and poor compliance with diaries and the protocol. Recruitment from the hospital resulted in participants with more severe asthma than anticipated. The results also suggest that many of the patients in this group will continue to have exacerbations triggered by upper or lower respiratory tract infections.

Adolescent↗
PubMed1996

High-dose chemotherapy supported by peripheral blood progenitor cells in poor prognosis metastatic breast cancer--phase I/II study. Edinburgh Breast Group.

Current treatments for metastatic breast cancer are not associated with significant survival benefits despite response rates of over 50%. High-dose therapy with autologous bone marrow transplantation (ABMT) has been investigated, particularly in North America, and prolonged survival in up to 25% of women has been reported, but with a significant treatment-related mortality. However, in patients with haematological malignancies undergoing autologous transplantation, haematopoietic reconstruction is significantly quicker and mortality lower than with ABMT, when peripheral blood progenitor cells (PBPCs) are used. In 32 women with metastatic breast cancer, we investigated the feasibility of PBPC mobilisation with high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) after 12 weeks' infusional induction chemotherapy and the subsequent efficacy of the haematopoietic reconstitution after conditioning with melphalan and either etoposide or thiotepa. PBPC mobilisation was successful in 28/32 (88%) patients, and there was a rapid post-transplantation haematopoietic recovery: median time to neutrophils > 0.5 x 10(9) l-1 was 14 days and to platelets > 20 x 10(9) l-1 was 10 days. There was no procedure-related mortality, and the major morbidity was mucositis (WHO grade 3-4) in 18/32 patients (56%). In a patient group of which the majority had very poor prognostic features, the median survival from start of induction chemotherapy was 15 months. Thus, PBPC mobilisation and support of high-dose chemotherapy is feasible after infusional induction chemotherapy for patients with metastatic breast cancer, although the optimum drug combination has not yet been determined.

Adult↗
PubMed1992

Effect of instructions on isokinetic trunk strength testing variability, reliability, absolute value, and predictive validity.

Although isokinetic strength testing has been in use for more than two decades, and numerous studies have addressed isokinetic performance of the lumbar spine, the effect of instructions on isokinetic trunk strength has not been studied. In a sample of 30 healthy women, this study examined the effect of "high-demand" instructions on lumbar strength performance. High-demand instructions were found to have a substantial positive effect on performance variability, reliability, absolute magnitude, and validity. Under these conditions, isokinetic trunk strength was found to be predictive of performance in a frequent lifting-lowering task.

Adult↗
PubMedDate not supplied

Critical evaluation of models developed for monitoring an industrial submerged bioprocess for antibiotic production using near-infrared spectroscopy.

Near-infrared spectroscopy (NIRS) is known to have potential for cost-effective monitoring of bioprocesses. Although this has been demonstrated in many instances and several models have been reported, information regarding the complexity of models required and their utility over extended periods of time is lacking. In the present study, the complexity of the models required for the NIRS prediction of substrate (oil) and product (tylosin) concentration in an industrial bioprocess that employs a physicochemically heterogeneous medium for antibiotic production was assessed. Measurements made by both the diffuse reflectance and transmittance modes were investigated. SEP values for the prediction of the analytes averaged 5% or less, for the successful models, when evaluated using an external validation set, 2 years after the initial model development exercise. Diffuse reflectance measurements showed poorer results, compared to transmittance measurements, especially for monitoring tylosin. In general, this investigation provides evidence to support the fact that models built for the prediction of analytes in a commercial bioprocess that employs a physicochemically complex production medium can be robust in performance over an extended period of time and that simple models based on fewer terms or latent variables can perform well, even in the context of matrices that are relatively complex. It also indicates that sample presentation is likely to be a critical factor in the successful application of NIRS in bioprocess monitoring, which merits further detailed investigation.

Anti-Bacterial Agents↗