PubMed Health⌕ Search

Biomedical subjects

B Swanson

Publications and source records attributed to B Swanson.

At least 19 recordsLinked to original sources
PubMed2003

Low-fat set yogurt made from milk subjected to combinations of high hydrostatic pressure and thermal processing.

The combined use of high hydrostatic pressure (300 to 676 MPa, 5 min) and thermal treatment (85 degrees C, 30 min) in milk for the manufacture of low-fat yogurt was studied. The objective was to reduce syneresis and improve the rheological properties of yogurt, reducing the need for thickeners and stabilizers. The use of high hydrostatic pressure alone, or after thermal treatment, reduced the lightness and increased the viscosity of skim milk. However, milk recovered its initial lightness and viscosity when thermal treatment was applied after high hydrostatic pressure. The MALDI-TOF spectra of skim milk presented monomers of whey proteins after a treatment of 676 MPa for 5 min. Yogurts made from skim milk subjected to 400 to 500 MPa and thermal treatment showed increased yield stress, resistance to normal penetration, and elastic modulus, while having reduced syneresis when compared to yogurts from thermally treated or raw milks. The combined use of thermal treatment and high hydrostatic pressure assures extensive whey protein denaturation and casein micelle disruption, respectively. Although reaggregation of casein submicelles occurs during fermentation, the net effect of the combined HHP and thermal treatment is the improvement of yogurt yield stress and reduction of syneresis.

Animals↗
PubMed2001

Detection of multivalent interactions through two-tiered energy transfer.

A method based on two-tiered fluorescence resonant energy transfer (FRET) has been developed for selective and sensitive detection of species involved in a multivalent interaction. Pentavalent binding between cholera toxin and ganglioside GM1 is used as a model system to demonstrate the advantage of the two-tiered FRET over one-stage FRET in both conventional fluorimeter and flow cytometer. In the system, three fluorescent probes (namely, fluorescence donor, acceptor, and intermediate) are covalently tagged to receptors, and the intermediate is used to bridge the energy transfer between the donor and acceptor even though the donor's fluorescence spectrum does not overlap with absorption spectrum of the acceptor. One of the most significant improvements of the scheme over one-stage FRET is a dramatic decrease in the background fluorescence of the acceptor fluorescence, which, theoretically and practically, increases the detection sensitivity.

Binding Sites↗
PubMed2000

Flow cytometry-based biosensor for detection of multivalent proteins.

Microsphere-based flow cytometric detection of cholera toxin (CT) through distance-dependent fluorescence resonant energy transfer (FRET) has been developed. Simultaneous double-fluorescence changes induced by multivalent interactions between CT and fluorophore (both fluorescence donor and acceptor)-labeled ganglioside GM1 on a biomimetic membrane surface (supported bilayers of phospholipids) can be measured by a commercial flow cytometer, providing a convenient and sensitive detection method for CT. The flow cytometry-based biosensor is capable of detecting less than 10 pM CT within 30 min. The signal generation strategy coupled with flow cytometry also provides a convenient method for kinetic studies of multivalent interactions. The surface density and the ratio of donor/acceptor-labeled GM1 on the surfaces of phospholipid bilayers are optimized to achieve high sensitivity.

Biosensing Techniques↗
PubMed2000

Efficacy of a vibratory stimulus for the relief of HIV-associated neuropathic pain.

Pain related to HIV disease is frequently debilitating. Of the many pain syndromes that occur in persons with HIV, distal symmetrical polyneuropathy (DSPN) is particularly devastating. Because DSPN often responds, at best, only partially to available pharmacologic interventions, non-pharmacologic interventions need to be investigated. Vibration has been suggested to be effective for reducing pain in other populations with chronic pain. This randomized, sham-controlled, double-masked study tested the short-term efficacy of a 45-min vibration treatment for DSPN foot pain in persons infected with HIV. Vibration therapy was delivered using a portable platform foot vibrator that provided stimulation at a frequency of 60 Hz. For all patients, the control box for the vibrator emitted an audible hum and part of the control box lit up during treatment, but only patients randomized to active treatment received vibration. Pain intensity (0-10) was measured immediately prior to and after treatment. Subjects were also questioned regarding pain relief (0-100%) immediately after the treatment. The mean percentage pain relief was 61.0+/-33.1% (median 70.0; range 0-100) for all patients, 67.3+/-34.0% (median 80.0; range 0-100) for vibration patients, and 55.0+/-32.0% (median 60.0; range 0-100) for sham patients. No statistically significant differences were found between the vibration and sham groups with respect to percentage pain relief (Mann-Whitney test; P=0.19) or the pre- and post-treatment current-pain difference (Mann-Whitney test; P=0.92). These results underscore the necessity for control groups in studies of non-pharmacologic therapies for pain.

Adult↗
PubMed2000

Homeostasis of alpha beta TCR+ T cells.

Cytokines contribute to T cell homeostasis at all stages of T cell existence. However, the particular cytokine involved varies as T cells progress from a naïve through an activated to a memory state. In many cases the important cytokines are members of the interleukin 2 subfamily of the short-chain type I cytokines. A case is made for the idea that the evolutionary divergence of the short-chain family allowed for concurrent divergence in leukocytes.

Animals↗
PubMed1999

Information technology and under-served communities.

Advances in information technology (IT) and telecommunications offer many potential benefits to Australia's under-served communities. However, there is also a risk that some of these communities will only be further disadvantaged, as IT will not contribute greatly to bringing groups such as the mentally ill and illiterate into the mainstream of the community. However, other under-served groups may experience service improvements. For people who do not have English as their first language, IT developments provide opportunities for cheaper and easier service and information delivery in their own languages. Telemedicine and IT also have the potential to make working in rural areas more attractive. On the other hand, telemedicine may be used as a means to bypass local health service providers, as has happened with other service industries. The health sector, though, is well behind these other industries in adopting IT and telecommunications. The growth of telemedicine projects is one indication that progress is being made, however. Two case studies--of telepsychiatry, and of medical education at Flinders University--provide examples of major Australian successes. The medical workforce implications will involve the overall numbers and mix of practitioners, their geographical distribution, changing professional boundaries and changing skill requirements. The only certain effect is that if IT changes the nature of medical work, large numbers of medical practitioners will need to improve their computer skills and older practitioners will find this most difficult.

Australia↗
PubMed1998

Determination of metformin in plasma by high-performance liquid chromatography after ultrafiltration.

A rapid high-performance liquid chromatography (HPLC) method was developed for determination of metformin, an oral antidiabetic agent, in plasma. Sample preparation entailed a 30-min centrifugation of plasma through a micron filter with direct injection of the protein-free ultrafiltrate into an HPLC system consisting of a cation-exchange extraction column (7.5x4.6 mm), a column switching valve, and a cation-exchange analytical column (250x4.6 mm). The eluent was monitored at 232 nm. Metformin was well resolved at a retention time of about 5 min. There was less than 2% loss of metformin during ultrafiltration and good linearity was established from 0.10 to 40 mg/l of metformin hydrochloride. The lower limit of quantitation was about 0.05 mg/l, at which concentration the signal-to-noise was above 10. The intra- and inter-assay coefficients of variation at plasma concentrations of metformin hydrochloride between 0.25 and 25 mg/l were typically 0.8-1.4% and 3.5-6.4%, respectively. This method offers a rapid sample preparation time and achieves excellent sensitivity without resorting to extraction and evaporation techniques.

Anticoagulants↗
PubMed1998

Minimizing HIV/AIDS malnutrition.

HIV/AIDS malnutrition influences immune function, disease progression, and quality of life. Changes in dietary intake, altered metabolism, and malabsorption are among the mechanisms that contribute to the nutritional alterations seen in HIV/AIDS. Medical-surgical nurses can help their patients minimize HIV/AIDS malnutrition through early and ongoing assessment, which guides nutritional and pharmacologic interventions.

HIV Infections↗
PubMed1996

Lens tropomodulin: developmental expression during differentiation.

Lens epithelial cells undergo a dramatic transformation during the process of differentiation into elongated fiber cells. The membrane-associated actin cytoskeleton is likely to play a critical role in the stabilization and maintenance of the highly elongated fiber cell shape. Tropomodulin is a tropomyosin-binding protein associated with actin filaments in a variety of terminally differentiated cell types where stable actin filament organization is required for cell function. We now present results of studies to determine the temporal expression of tropomodulin in the developing lens. In situ hybridization experiments detected expression of tropomodulin mRNA in the developing mouse lens in elongating cells with a pattern similar to that of the fiber specific beta- and gamma-crystallins. Tropomodulin mRNA expression first appeared around 11.5 days post-coitum in elongating cells in the posterior part of the lens vesicle. At later stages the signal for tropomodulin was present in the elongating cells at the lens equator and in cortical fiber cells; signal was absent from the epithelium. To investigate the possible link between tropomodulin expression and fiber differentiation we used a well-established lens epithelial explant culture system in which fiber differentiation is induced by fibroblast growth factor (FGF). Tropomodulin expression was only observed in FGF-treated explants in conjunction with morphologic changes characteristic of lens fiber cell differentiation. The appearance of tropomodulin during the process of fiber cell differentiation suggests that tropomodulin may be important for stabilization and/or determination of actin filament length.

Animals↗
PubMed1996

Psychoneuroimmunology: an emerging framework for nursing research.

Psychoneuroimmunology (PNI) is concerned with the mechanisms of bidirectional communication between the neuroendocrine and immune systems. Investigators in other disciplines have used this framework to guide the examination of possible relationships between behavioural factors and the progression of immunologically mediated illnesses and to evaluate the role of immune products in central nervous system disturbances. Nurse scientists have an opportunity to make unique contributions to the growing field of PNI. Unlike basic science research, which has as its goal the generation of fundamental knowledge concerning biological or behavioural processes, nursing research is driven by the need to promote excellence in nursing science as a guide for nursing practice. Although a few nurse scientists have conducted PNI research to date, additional studies are needed to generate new knowledge concerning mind-body interactions in health and illness and to develop strategies that promote mental and physical well-being in persons at risk for immune dysfunction. This paper highlights the few recently conducted nursing studies grounded in a PNI framework to illustrate the utility of PNI in advancing nursing science.

Health Promotion↗
PubMed1995

Cloning of tropomodulin cDNA and localization of gene transcripts during mouse embryogenesis.

Tropomodulin (Tmod) is a tropomyosin-binding protein involved in the structuring of actin filaments. This report describes Tmod expression in distinct patterns during embryonic development in a wider variety of adult and embryonic vertebrate tissues than previously reported. Identical Tmod cDNAs were cloned from mouse brain, skeletal muscle, heart, and hematopoeitic cells. Genomic blotting demonstrates that Tmod is encoded by a single gene, which has a 1077-bp open reading frame that is highly homologous to that of the human erythrocyte. The spatial and temporal expression of the Tmod gene was examined during mouse embryogenesis using in situ hybridization. Tmod mRNA is present by 9.5 days postcoitum (p.c.) in the developing rostral somites, coincident with expression of contractile protein genes in myotomes, suggesting that Tmod may play an important role in sarcomeric thin filament organization in skeletal muscle. While the expression of Tmod mRNA in cardiac muscle is earlier than that in skeletal muscle, its appearance in the heart also coincides with the expression of genes for thin filament proteins and correlates with initial myocardial contractions at 8.0 days p.c. Tmod mRNA is not detected in developing smooth muscle of the gut, but Tmod mRNA is expressed in hematopoeitic cells in yolk sac and developing liver. The sensory ganglia and epithelia of the inner ear express Tmod mRNA as do other sensory neurons such as those in the olfactory epithelium. Expression levels in the brain are much lower prenatally than postnatally. These findings show that Tmod expression in many cell types is developmentally regulated, suggesting that the interaction of actin filaments with this tropomyosin binding protein is an important process in tissue and cell differentiation.

Amino Acid Sequence↗
PubMed1993

Characterizing the neuropsychological functioning of persons with human immunodeficiency virus infection, Part I. Acquired immunodeficiency syndrome dementia complex: a review.

The findings of studies that use psychoneuroimmunological frameworks can help nurses evaluate and treat patients' psychological and physical responses to infection with the human immunodeficiency virus (HIV). One response to HIV infection, acquired immunodeficiency syndrome (AIDS) dementia complex (ADC), may occur at any stage of the infection and is particularly distressing to both patients and nurses. In Part I of this series, current research pertinent to ADC is reviewed. In Part II, we describe an approach used to characterize the neuropsychological functioning of persons at different stages of HIV infection.

AIDS Dementia Complex↗
PubMed1993

Characterizing the neuropsychological functioning of persons with human immunodeficiency virus (HIV) infection, Part II. Neuropsychological functioning of persons at different stages of HIV infection.

Neuropsychological impairment has been reported to occur in persons at all stages of infection with the human immunodeficiency virus (HIV). However, the findings of studies to characterize the incidence and pattern of impairment have been limited by inconsistent definitions of impairment and the failure to control for confounding variables, such as hematological abnormalities, history of head injury, or substance abuse. In the present study, neuropsychological tests were administered to 141 persons at four stages of HIV infection. Significant differences were found in the percentage of persons who showed impairment at each stage of infection. Further, participants' performance on the tests tended to decline across progressive stages of infection. These findings may help psychiatric nurses identify and manage the changes associated with HIV infection.

AIDS Dementia Complex↗