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Biomedical subjects

B Fuller

Publications and source records attributed to B Fuller.

At least 19 recordsLinked to original sources
PubMed2005

Carbon monoxide-releasing molecules (CO-RMs) modulate respiration in isolated mitochondria.

Emerging evidence reveals that heme oxygenase-1 (HO-1) and its product carbon monoxide (CO) can exert diverse biological and cytoprotective effects. Our group has recently identified a new class of compounds (CO-releasing molecules or CO-RMs) that can carry and deliver CO to biological systems and can be used to examine the physiological properties of CO. Here, we evaluated the influence of endogenously-generated CO (via HO-1 induction by hemin) and CO liberated from exogenously supplied CO-RMs on mitochondrial function. Renal mitochondria were isolated either from rats with increased HO-1 or from untreated animals, the latter being exposed to different concentrations of CO-RMs (10-100 microM). We found that mitochondrial oxygen uptake was significantly reduced in kidneys after HO-1 induction and, in a similar fashion, CO-RMs inhibited mitochondrial function in a concentration-dependent manner. Specifically, a marked depression of state 3 was observed resulting in a significant decrease in respiratory control index (RCI) values. When mitochondria were incubated with the inactive forms of CO-RMs, which are devoid of CO, the respiratory parameters remained unchanged. In summary, the results indicate that HO-1 induction and enhanced CO decrease renal oxygen consumption and alter mitochondrial function suggesting that CO could be a physiological regulator of mitochondrial oxidative phosphorylation.

Animals↗
PubMed2004

Cellular engineering of conduits for coronary and lower limb bypass surgery: role of cell attachment peptides and pre-conditioning in optimising smooth muscle cells (SMC) adherence to compliant poly(carbonate-urea)urethane (MyoLink) scaffolds.

OBJECTIVE: We are developing a hybrid arterial bypass graft of compliant poly(carbonate-urea)urethane (MyoLink), endothelial and smooth muscle cells (SMCs). To enhance adhesion of SMCs we assessed various attachment factors and the effect of pre-conditioning on cell retention. METHODS: MyoLink segments were coated with either RGD, superfibronectin, fibronectin, fibronectin-like engineered polymer protein (FEPP), FEPP plus or type 1 collagen overnight. (111)Indium-radiolabelled SMCs were placed onto MyoLink segments for 48 h before being aspirated, then lavaged off. All grafts, aspirates and lavages were counted in a gamma counter. SMC viability on the MyoLink segments was also assessed for viability using the Alamar blue redox assay. Separately, MyoLink grafts lined with radiolabelled SMCs were divided into a pre-conditioned group, exposed to subarterial pulsatile flow whilst another group were held in static culture. After 1-week, grafts were exposed to arterial pulsatile flow whilst radioactivity was assessed using a gamma camera. RESULTS: Only FEPP plus significantly enhanced SMC attachment: mean of 32+/-6% cell attachment compared to 21+/-5% for uncoated control. Cell viability was enhanced by all attachment factors except fibronectin. Pre-conditioning was shown to significantly enhance the retention of SMCs onto the MyoLink once exposed to pulsatile arterial flow: the final attachment was 57+/-7% for the static and 76+/-7% for the pre-conditioned group. CONCLUSIONS: FEPP plus enhances SMC attachment to MyoLink. We believe this is because of its repeating sequences of RGD and its positive charge. Pre-conditioning enhances the retention of SMCs to MyoLink once exposed to pulsatile arterial flow.

Blood Vessel Prosthesis↗
PubMed2003

Hepatic cold hypoxia and oxidative stress: implications for ICAM-1 expression and modulation by glutathione during experimental isolated liver preservation.

Cold preservation and reperfusion of liver during transplantation are necessary steps in the procedure but which are also associated with damage to the organ. One aspect of this damage is thought to concern up-regulation of inflammatory markers, such as the adhesion molecule intercellular adhesion molecule 1 (ICAM-1) on target cells in the liver. This aids sequestration of activated leucocytes, which promote inflammation, by a complex sequence of events, including free radical mediated damage. We have studied changes in ICAM-1 in rat liver as a consequence of cold preservation for various times, and also after warm reperfusion during isolated liver perfusion. We have also investigated the effects of the free radical scavenging agent (reduced glutathione-GSH) on the modulation of ICAM-1 expression after cold hypoxia and reperfusion. Livers were subjected to various regimes of cold preservation and reperfusion. Liver biopsies were taken at three time points (initial baseline on liver exposure; after organ flushing and post-storage at 0, 8, 16, and 24h cold hypoxia in University of Wisconsin solution; in the same livers after 1h warm reperfusion). The tissues were processed for frozen biopsy work, and frozen sections were stained using immunohistochemical methods, for blinded scoring by an independent observer. Positive controls were obtained by exposure to endotoxin lipopolysaccharide before liver flushing. ICAM-1 expression was low in control livers (0.33+/-0.21), and increased to near maximal (2.83+/-0.17) after endotoxin exposure. ICAM-1 expression increased progressively with cold preservation, reaching values of 1.17+/-0.31 and 1.83+/-0.31 after 16 and 24h, respectively (P<0.05 and 0.02 versus controls). Warm reperfusuion increased ICAM-1 expression in all flushed groups and with longer cold preservation was close to maximal (2.67+/-0.21 after 16h and 2.98+/-0.02 after 24h; P<0.001 in both cases). Addition of the free radical scavenger GSH prevented up-regulation of ICAM-1 in livers reperfused after flushing and cold storage for up to 8h; beyond this time, ICAM-1 expression still increased, such that by 24h cold preservation and reperfusion absence (2.98+/-0.02) or presence (2.67+/-0.21) made no difference. We conclude that liver ICAM-1 expression is demonstrably increased by progressive cold preservation and reperfusion, and is only marginally affected by addition of GSH during reperfusion. The model can be used to investigate other agents which might be more successful in preventing post-storage inflammatory damage.

Animals↗
PubMed2002

A simple non-enzymatic method for the isolation of high yields of functional rat hepatocytes.

A method for isolation of rat hepatocytes using liver perfusion by ethylenediamine tetra-acetic acid (EDTA)-containing sucrose solution and mechanical tissue disaggregation by controlled vibration (MVD) is described. The yields of hepatocytes produced by this method were similar to those obtained using collagenase perfusion. The cells had well preserved membrane integrity as judged by the trypan blue staining test (91 +/- 4%), ATP contents, rates of endogenous respiration and enzyme leakage that indicated they were functional cells. There was little evidence of expression of latent damage when the cells were stored either at 37 degrees C (by pre-incubation) or at 4 degrees C. This method can be used to isolate high yields of functional cells from rat liver if the collagenase perfusion technique is not available.

Animals↗
PubMed2001

Intramedullary spinal cord metastasis from renal cell carcinoma: detection by positron emission tomography.

Although positron emission tomography (PET) is an established diagnostic method in brain and lung cancer, its use is often confined to research. The authors report a case of a minimally symptomatic intramedullary spinal cord metastasis, an uncommon and often diagnostically challenging lesion, that was confirmed by PET. A 37-year-old man with a history of metastatic renal cell carcinoma treated with systemic agents, an autologous stem cell transplant, and local palliative radiotherapy with a 2-month history of vague right foot numbness and right leg dysesthesias was found to have an intramedullary lesion at the level of T12. Although the findings of magnetic resonance imaging suggested central necrosis, a PET scan revealed a metabolically active lesion and confirmed the diagnosis of intramedullary metastasis. PET can be used to detect and confirm intramedullary spinal cord metastatic carcinoma. PET imaging may have a vital role in clinical diagnosis by helping to distinguish diagnostically troublesome lesions based on metabolic activity.

Adenocarcinoma, Clear Cell↗
PubMed2001

Privacy of genetic information: a review of the laws in the United States.

This paper examines the privacy of genetic information and the laws in the United States designed to protect genetic privacy. While all 50 states have laws protecting the privacy of health information, there are many states that have additional laws that carve out additional protections specifically for genetic information. The majority of the individual states have enacted legislation to protect individuals from discrimination on the basis of genetic information, and most of this legislation also has provisions to protect the privacy of genetic information. On the Federal level, there has been no antidiscrimination or genetic privacy legislation. Secretary Donna Shalala of the Department of Health and Human Services has issued proposed regulations to protect the privacy of individually identifiable health information. These regulations encompass individually identifiable health information and do not make specific provisions for genetic information. The variety of laws regarding genetic privacy, some found in statutes to protect health information and some found in statutes to prevent genetic discrimination, presents challenges to those charged with administering and executing these laws.

Confidentiality↗
PubMed1999

Isolation of human hepatocytes after hepatic warm and cold ischemia: a practical approach using University of Wisconsin solution.

A method is described for isolating human hepatocytes from tissue fragments after warm and cold ischemia as experienced during hepatic resections. Cells with a high trypan blue dye exclusion and good culture characteristics were isolated by employing an initial tissue perfusion with UW solution. The method could facilitate transfer of liver tissues between distant centers for cell isolation studies.

Adenosine↗
PubMed1998

Early child-care selection: variation by geographic location, maternal characteristics, and family structure.

More than half of all U.S. infants and toddlers spend at least 20 hr per week in the care of a nonparent adult. This article uses survival analysis to identify which families are most likely to place their child in care and the ages when these choices are made, using data from a national probability sample of 2,614 households. Median age at first placement is 33 months, but age varies by geographic region, mother's employment status during pregnancy, mother's education level, and family structure (1 vs. 2 parents, mother's age at 1st birth, and number of siblings). Controlling for these effects, differences by race and ethnicity are small. Implications for studies of child-care selection and evaluations of early childhood programs are discussed.

Adolescent↗
PubMed1997

The influence of cryopreservation on murine oocyte water permeability and osmotically inactive volume.

Osmotic experiments were performed on unfrozen (N = 18) and cryopreserved (N = 21) ICR murine oocytes in order to determine whether a standard cryopreservation process alters membrane water permeability (hydraulic conductivity, Lp) and/or osmotically inactive volume (Vb). Oocytes, initially in an isotonic (288 mOsm) NaCl solution, were exposed to 900 mOsm NaCl in a microdiffusion chamber. Cell size changes were videotaped and analyzed using a parameter estimation program. Best estimates for a two-parameter model (Lp and Vb) which includes the osmotically inactive volume as a fitting parameter are presented for the first time. The cryopreservation process produced no significant difference between the mean Lp or the mean Vb values for the unfrozen control population (Lp = 0.64 +/- 0.15 micron/min/atm, Vb = 24.7 +/- 2.9%) and the cryopreserved population (Lp = 0.63 +/- 0.12 micron/min/atm, Vb = 28.0 +/- 10.8%). While the cryopreservation process did not cause significant changes in the mean values of Lp, Vb, or the variability of Lp, it did produce more variability of Vb. The cause of the increased variability of Vb produced by cryopreservation is unknown. These results suggest that the osmotic properties of unfrozen control oocytes can be used as a reasonable approximation for frozen-thawed oocytes. They also suggest that multiple parameter models and parameter estimation methods may be useful in developing a more comprehensive understanding of the more subtle alterations in osmotic properties that were detected here. Statistical tests were also used for the first time to confirm the assumption that all of the experimental populations were derived from normal distributions.

Animals↗
PubMed1997

The relation between leadership style and empowerment on job satisfaction of nurses.

OBJECTIVE: The authors explore the relation between leadership style and empowerment and its effect on job satisfaction among the nursing staff of a regional medical center. BACKGROUND: Several empirical studies on transformational leadership-found that transformational leadership behaviors were positively related to work team success and leadership effectiveness. Transformational leadership processes have also been suggested to enhance followers' work-oriented values and shape the self-efficacies of followers. Employee empowerment may be influenced by the perception that the organization cares about its employees' well-being and that their work is valued. Empowering nurses may increase job satisfaction and improve patient care. Leadership style and empowerment influence job satisfaction among workers. METHODS: All nursing department staff were invited to complete a self-report questionnaire with no identifying information. Leadership style was measured using Bass's Multifactor Leadership Questionnaire, empowerment was measured with items from Spreitzer's Psychological Empowerment instrument, and job satisfaction was measured by Warr, Cook, and Wall's job satisfaction questionnaire. RESULTS: Both transformational and transactional leadership were positively related to job satisfaction, as was empowerment. Differences in the contributions of empowerment and leadership style in predicting job satisfaction for licensed and unlicensed workers was evident. CONCLUSION: Designing interventions that allow for the relative influence of leadership style as well as empowerment on varying classifications of nursing personnel may be a more effective strategy and have a greater effect on staff attitudes and behaviors.

Decision Making, Organizational↗