PubMed Health⌕ Search

Biomedical subjects

C Swenson

Publications and source records attributed to C Swenson.

At least 19 recordsLinked to original sources
PubMed2001

Comparative concentrations of metals in marine species from French Frigate Shoals, North Pacific Ocean.

Concentrations of arsenic, cadmium, chromium, copper, lead, mercury, selenium, and zinc were measured in coral, crab, eel, fish, lobster, and sediment samples collected from French Frigate Shoals, North Pacific Ocean. The sediments contained relatively high concentrations of selenium; moderate concentrations of arsenic, cadmium, copper and lead; and low concentrations of chromium and zinc. Metal concentrations were also determined in coral and crabs collected from the island of Oahu. Notably, a crab (Grapsus tenuicrustatus) and the undulated moray eel (Gymnothorax undulatus) exhibited high levels of copper and arsenic, respectively, relative to the other species studied. The concentrations of arsenic in the eel averaged 225 microg g(-1) dry wt, which was 3-12 times higher than that in all of the other species tested. The average concentration of copper in the crab was 343 microg g(-1) dry wt, 3-86 times greater than that in the other species studied. These data indicate background and comparative levels of the metals among the studied species. Lead levels in the coral (9-10 microg g(-1) dry wt) and crab (42-57 microg g(-1) dry wt) from Tern and Disappearing Islands were 23-283-fold greater than those from Oahu (0.4 and 0.2 microg g(-1) dry wt, respectively).

Animals↗
PubMed2001

Antibody responses of cattle immunized with the Tf190 adhesin of Tritrichomonas foetus.

The antibody response patterns of cattle after subcutaneous and intranasal immunizations with adhesin Tf190 of Tritrichomonas foetus were investigated. Reactions of antibody from cattle parenterally immunized with Tf190 revealed antigen specificity and Tf190 sensitization in the majority of the animals, as determined by Western blotting. The results also demonstrated strong preimmune immunoglobulin G2 (IgG2) binding to T. foetus antigens not seen in IgG1 profiles. Subcutaneous injections of Tf190 resulted in significant (P < 0.05) increases in serum IgG1 and IgG2 titers over time, as determined by parasite specific enzyme-linked immunosorbent assay. Immune sera also significantly inhibited parasite adhesion to mammalian cell lines compared to the level of inhibition obtained with preimmune sera (P < 0.05). Intranasal immunization with Tf190 failed to produce measurable parasite-specific antibody in serum; however, this immunization route did result in significant (P < 0.05) increases in parasite-specific IgA titers in cervical mucus secretions from immunized animals that were more resistant to intravaginal challenge with T. foetus than controls. These results suggest that systemic immunization with Tf190 results in serum antibody production and antiparasitic adhesin antibodies. Additionally, the results of challenge experiments with intranasally immunized animals suggests that Tf190 primes protective immune responses that lead to lower rates of infection among these animals.

Adhesins, Bacterial↗
PubMed2000

Retinoids as ligands and coactivators of protein kinase C alpha.

Whereas retinoic acids control nuclear events, a second class of retinol metabolites, that is, the hydroxylated forms exemplified by 14-hydroxy-retro-retinol (HRR), operate primarily in the cytoplasm. They function as regulatory cofactors for cell survival/cell death decisions. In accordance with these biological aspects, we demonstrate that these retinoids bound protein kinase C (PKC) alpha with nanomolar affinity and markedly enhance the activation of PKC alpha and the entire downstream MAP kinase pathway by reactive oxygen species. HRR was 10 times more efficient than retinol, and the optimum doses are 10-7 and 10-6 M, respectively. PKC alpha activation was reversed rapidly by imposition of reducing conditions. The retinoid binding site was mapped to the first cysteine-rich region in the regulatory domain, C1A, yet was distinct from the binding sites of diacylglycerol and phorbol esters. The C1B domain bound retinoids poorly. The emerging theme is that retinoids serve as redox regulators of protein kinase C.

3T3 Cells↗
PubMed2000

The cysteine-rich regions of the regulatory domains of Raf and protein kinase C as retinoid receptors.

Vitamin A and its biologically active derivatives, the retinoids, are recognized as key regulators of vertebrate development, cell growth, and differentiation. Although nuclear receptors have held the attention since their discovery a decade ago, we report here on serine/threonine kinases as a new class of retinoid receptors. The conserved cysteine-rich domain of the NH(2)-terminal regulatory domains of cRaf-1, as well as several select domains of the mammalian protein kinase C (PKC) isoforms alpha, delta, zeta, and mu, the Drosophila and yeast PKCs, were found to bind retinol with nanomolar affinity. The biological significance was revealed in the alternate redox activation pathway of these kinases. Retinol served as a cofactor to augment the activation of both cRaf and PKC alpha by reactive oxygen, whereas the classical receptor-mediated pathway was unaffected by the presence or absence of retinol. We propose that bound retinol, owing to its electron transfer capacity, functions as a tag to enable the efficient and directed redox activation of the cRaf and PKC families of kinases.

3T3 Cells↗
PubMed2000

Distribution of polychlorinated biphenyls in marine species from French Frigate Shoals, North Pacific Ocean.

Polychlorinated biphenyls (PCBs) were analyzed in: sediment; coral (Porites evermanni); fish (Stegastes fasciolatus, Neoniphon sammara, Acanthurus triostegus and Mulloidichthys vanicolensis); crab (Grapsus tenuicrustatus); lobster (Panulirus marginatus); and eel (Conger cinereus, Gymnothoraxflavimarginatus, G. undulatus and G. meleagris) samples collected from Tern Island and the corresponding reference samples from Disappearing Island. The two islands are part of French Frigate Shoals, a national wildlife refuge in the North Pacific Ocean. The dominant congeners 118, 138 and 153 represent 22-25, 32-34, 12-39, 37-46 and 30-55% of the sum of PCBs in the coral, sediment, fish, crab and eel, respectively. In general, high trophic species such as eels were found to highly bioaccumulate PCBs. The total average PCB concentrations were as high as 96 and 29 microg/g dry wt. in eels and damselfish, respectively, from Tern Island. The localized behavior and high bioaccumulation potential for PCBs suggest that damselfish are an excellent species for monitoring PCBs in small areas in the ocean. The high average concentrations of the sum of PCBs in different food chain levels suggest that pollution source(s) are around Tern Island and possibly around Disappearing Island. Aroclor 1254 and its analogs are suspected sources responsible for PCBs in the samples.

Animals↗
PubMed2000

Polychlorinated biphenyls and metals in marine species from French Frigate Shoals, North Pacific Ocean.

Polychlorinated biphenyls (PCBs) and metals were analyzed in coral (Porites lobata), fish (Stegastes fasciolatus), crab (Grapsus tenuicrustatus), and sediment samples collected from Tern Island, and the reference samples from Trig and La Perouse Islands. All three islands are part of French Frigate Shoals, a national wildlife refuge in the North Pacific Ocean. Average concentrations of total PCBs ranged from 154 to 274 ng/g in the sediments, from 120 to 267 ng/g in the corals, from 387 to 4,500 ng/g in the crabs, and 1,340 to 46,000 ng/g, dry weight, in the fishes. High concentrations in marine species indicate there is PCB source(s) in French Frigate Shoals, especially Tern Island. Tetra- and pentachlorobiphenyls were 64-66% of the total PCB levels in the sediments, and they accounted for 57-65% of total PCBs in the corals. Penta- and hexachlorobiphenyls were 76-84% of total PCBs in the fishes, and they accounted for 79-85% in the crab samples. The sediment and coral were predominated by lower chlorinated PCB congeners, whereas the fish and crab bioaccumulated mainly higher chlorinated congeners. Selenium concentrations (16-23 microg/g) in sediments were much higher than some reported baseline values (0.4-2.5 microg/g). The average concentrations of arsenic, cadmium, lead, and selenium in the coral and fish were about equal to or less than those in the sediments. Concentrations of arsenic and cadmium in the crabs (49-51 and 3-4 microg/g, respectively) were approximately twofold of those in the sediments.

Animals↗
PubMed2000

Rhinovirus-induced PBMC responses and outcome of experimental infection in allergic subjects.

BACKGROUND: The immune response to rhinovirus (RV) infections is considered to contribute to upper respiratory symptoms and may also be an important contributor to lower airway dysfunction in patients with asthma. OBJECTIVE: This study was conducted to determine the relationship of RV-specific responses in PBMCs to the outcome of experimentally induced infection with RV16. METHODS: Twenty-two subjects with either allergic rhinitis or asthma were inoculated with RV16: virus-induced proliferation and cytokine production were determined on PBMCs obtained before and then again 7 and 28 days after inoculation. RESULTS: Several subjects had proliferative responses to RV16 before inoculation, and precold RV-specific proliferative responses were inversely correlated (r(s) = -0.62, P <. 005) with RV shedding after inoculation. In addition, there was a negative correlation (r(s) = -0.58, P = 0.01) between precold RV-induced IFN-gamma secretion ex vivo and peak RV shedding during the cold. CONCLUSIONS: Certain RV-specific lymphocyte responses before the cold (vigorous proliferation or IFN-gamma secretion) were associated with reduced viral shedding after inoculation. These findings suggest that variations in mononuclear cell responses to RV could contribute to the individual variability in viral shedding during experimentally induced, and perhaps naturally acquired, RV infections in subjects with respiratory allergy or asthma.

Adolescent↗
PubMed2000

Relationship of upper and lower airway cytokines to outcome of experimental rhinovirus infection.

To test the hypothesis that rhinovirus (RV)-induced immune responses influence the outcome of RV infections, we inoculated 22 subjects with allergic rhinitis or asthma with RV16. Nasal secretions and induced sputum were repeatedly sampled over the next 14 d. RV16 infection increased nasal granulocyte colony-stimulating factor (G-CSF) and interleukin (IL)-8, which was accompanied by neutrophilia in blood and nasal secretions. Nasal G-CSF correlated closely with increased blood neutrophils (r(s) = 0.69, p < 0.005), whereas nasal neutrophils correlated with both G-CSF (r(s) = 0.87, p < 0.001) and IL-8 (r(s) = 0.75, p < 0.001). Although similar relationships were present in sputum, changes in sputum neutrophils and G-CSF with RV16 infection were relatively modest. In addition, virus-induced changes in the sputum interferon-gamma-to-IL-5 messenger RNA ratio were inversely related to both peak cold symptoms (r(s) = -0.60, p < 0.005) and the time to viral clearance (undetectable picornavirus RNA). These results indicate that airway IL-8 and G-CSF are closely associated with virus-induced neutrophilic inflammation during an experimental RV infection in atopic volunteers. In addition, the balance of airway T-helper cell type 1 (Th1)- and Th2-like cytokines induced by RV infection may help determine the clinical outcome of common cold infections, raising the possibility that the individual subject's immune response, rather than atopic status per se, is important in this regard.

Adolescent↗
PubMed1999

Indicators of nutritional risk in a rural elderly Hispanic and non-Hispanic white population: San Luis Valley Health and Aging Study.

OBJECTIVE: To describe the prevalence of nutritional risk factors among elderly residents in a rural Hispanic and non-Hispanic white population. DESIGN: A geographically based survey of community-dwelling elderly adults. SUBJECTS/SETTING: From July 1993 to July 1995, all Hispanic persons older than 65 years and an age-stratified, random sample of 69% of non-Hispanic white persons, from 2 Colorado counties, were invited to participate in a study of functional impairment and disability (81% responded). After exclusion of 184 respondents who required a surrogate respondent and 8 with missing diet data, the study consisted of 1,006 subjects. Interviews included questions similar to the Nutrition screening Initiative checklist, a 21-item food frequency questionnaire, and anthropometric measures. STATISTICAL ANALYSES PERFORMED: Gender- and ethnicity-specific, age-adjusted prevalence for each risk factor was estimated by use of logistic regression. RESULTS: Hispanic participants were more likely than non-Hispanic whites to report inadequate intake of vegetables, problems with teeth or dentures that limited the kinds and amounts of food eaten, difficulty preparing meals, and lack of money needed to buy food. Hispanic women reported nutritional risk factors more often than Hispanic men, although anthropometric markers indicated that Hispanic men may be at higher risk of nutritional deficiency. APPLICATIONS/CONCLUSIONS: Hispanic men and women had a higher prevalence of nutritional risk factors than non-Hispanic whites. Intervention programs targeting rural, elderly Hispanics should aim to ensure that basic nutrition needs (access to food, help preparing meals, and adequate dental care) are being met. Community programs to increase activity levels and consumption of nutrient-dense foods are recommended.

Aged↗
PubMed1999

Methods and prevalence of ADL limitations in Hispanic and non-Hispanic white subjects in rural Colorado: the San Luis Valley Health and Aging Study.

PURPOSE: The Hispanic population in the United States is the fastest growing minority group, yet there is little understanding of the disability patterns that occur as this population ages. We conducted a cross-sectional study to define the prevalence of limitations of activities of daily living (ADL) and measures of observed function. METHODS: We censussed two rural counties in southern Colorado and selected a stratified sample of both Hispanic and non-Hispanic white (NHW) residents; 81.6% completed the protocol. RESULTS: Among the 1250 subjects aged 65 years and older, Hispanic elderly living in the community had greater ADL disability than NHW subjects, both for any difficulty (p = 0.006), and for needing assistance (p = 0.002). Hispanic persons were less likely to reside in nursing homes (3.4%) compared with NHW persons (9.3%). Hispanic elderly had excess prevalence of dependent ADL tasks (needs assistance or unable to do), (age, gender-adjusted odds ratio = 1.39, 95% CI = 1.01-1.92) in community dwelling and nursing home residents combined. There was no Hispanic excess of less severe difficulty compared with NHW persons, and there was a similar prevalence of limitation on observed functional tasks (timed walk, stooping, rising from a chair) in both groups. CONCLUSIONS: There was a modest Hispanic excess of reported dependent ADL limitation, and no excess of observed functional difficulties. Hispanics enter older age with much less income and education, yet they do not have a marked excess prevalence of limitations in activities of daily living when compared with NHW persons living in the same area.

Activities of Daily Living↗
PubMed1998

Tobacco-related instruction in undergraduate nursing education in Illinois.

Tobacco use is responsible for more deaths in the United States than any other factor. Nurses are in a unique position to convey life-saving messages to clients regarding tobacco use. To gauge the type and extent of tobacco-related background knowledge acquired by nurses in the course of their education, the Nurses' Committee of the Illinois Division of the American Cancer Society (ACS) surveyed 70 nursing programs in the state of Illinois. The number of lecture hours spent on tobacco-related issues was greater in LPN programs than in either associate or baccalaureate degree programs, and instruction was scattered throughout the curriculum of each program. Most schools reported heavy reliance on adult medical-surgical textbooks to convey tobacco-related content. The most recent editions of the textbooks used by the schools were reviewed, and they also were found to adopt a scattered approach, with a disappointing lack of depth regarding the hazards of tobacco. It is recommended a single course be identified as responsible for relaying tobacco-related content and information supplied by general medical-surgical textbooks be supplemented by materials drawn from other sources.

Curriculum↗
PubMed1997

Rhinovirus infection preferentially increases lower airway responsiveness in allergic subjects.

Rhinovirus (RV) infections are important triggers of acute asthma symptoms in susceptible persons. To determine whether the presence of allergy is a risk factor for enhanced lower airway effects during RV infection, we experimentally infected (RV16) 18 volunteers with allergic rhinitis and 13 normal control subjects and measured the effects on the response of the lower airways to histamine. All subjects were successfully infected, as indicated by increased upper respiratory symptoms and RV16 cultured from nasal secretions. The change in histamine PD20(deltaPD20) caused by RV infection was significantly different in allergic subjects from that in nonallergic control subjects (deltaPD20 = -0.40 versus -0.03 log units, p = 0.04). This relationship was strengthened after adjusting for initial PD20 and FEV1 (mean deltaPD20 = -0.43 versus 0.01 log units, p < 0.01). The virus-induced deltaPD20 was also influenced by baseline lung function: there was a positive correlation between initial FEV1 and deltaPD20, and a weak but significant negative correlation between baseline PD20 and deltaPD20. These findings indicate that host factors such as allergy, baseline FEV1, and baseline PD20 influence the changes in lower airway physiology caused by RV infection and raise the possibility that these factors contribute to the increased lower airway effects of RV infection in subjects with asthma.

Adult↗
PubMed1996

Reduction of canine infarct size by bolus intravenous administration of liposomal prostaglandin E1: comparison with control, placebo liposomes, and continuous intravenous infusion of prostaglandin E1.

Prostaglandin E1 (PGE1) reduces experimental infarct size when administered by prolonged low-dose left atrial infusion during coronary occlusion. Liposomal delivery of PGE1 may enhance biologic activity and limit adverse hemodynamic effects. The purpose of this study was to test the hypothesis that intravenous bolus administration of liposomal PGE1 (TLC C-53, The Liposome Company, Princeton, N.J.) during coronary occlusion would result in myocardial salvage. We compared TLC C-53 (0.5 microgram/kg intravenous bolus at 10 and 100 min of occlusion of the left anterior descending coronary artery [LAD]), free PGE1 (0.1 microgram/kg/min infused 10 min after LAD occlusion until reperfusion), placebo liposomes, and control (n = 7 for each group) in an open-chest canine model of 2 hours of LAD occlusion and reperfusion. Infarct size as a percentage of risk area (mean +/- SD) in the control group (58.4% +/- 20.0%) was similar to that in animals given placebo liposomes (53.1% +/- 12.6%) but was significantly reduced in the groups given TLC C-53 (33.5% +/- 9.2%; p < 0.01) or free PGE1 (37.2% +/- 4.8%; p < 0.05) groups. Infarct salvage was significant (p < 0.05) for the TLC C-53-and PGE1-treated dogs compared with the control dogs, independent of collateral blood flow by analysis of covariance. Moreover, the ischemic-zone blood flow during reperfusion was significantly higher in the TLC C-53 group compared with the control group or the group receiving free PGE1. Neutrophil infiltration of ischemic myocardium was significantly inhibited by TLC C-53 as determined by myeloperoxidase assay. Unlike free PGE1, TLC C-53 did not cause significant tachycardia or hypotension during therapy. In conclusion, TLC C-53 administered intravenously during coronary occlusion significantly reduced infarct size, limited neutrophil infiltration, and improved myocardial blood flow during reperfusion without adverse hemodynamic consequences.

Alprostadil↗
PubMed1996

Cryotherapy in sports medicine.

The use of cryotherapy, i.e. the application of cold for the treatment of injury or disease, is widespread in sports medicine today. It is an established method when treating acute soft tissue injuries, but there is a discrepancy between the scientific basis for cryotherapy and clinical studies. Various methods such as ice packs, ice towels, ice massage, gel packs, refrigerant gases and inflatable splints can be used. Cold is also used to reduce the recovery time as part of the rehabilitation programme both after acute injuries and in the treatment of chronic injuries. Cryotherapy has also been shown to reduce pain effectively in the post-operative period after reconstructive surgery of the joints. Both superficial and deep temperature changes depend on the method of application, initial temperature and application time. The physiological and biological effects are due to the reduction in temperature in the various tissues, together with the neuromuscular action and relaxation of the muscles produced by the application of cold. Cold increases the pain threshold, the viscosity and the plastic deformation of the tissues but decreases the motor performance. The application of cold has also been found to decrease the inflammatory reaction in an experimental situation. Cold appears to be effective and harmless and few complications or side-effects after the use of cold therapy are reported. Prolonged application at very low temperatures should, however, be avoided as this may cause serious side-effects, such as frost-bite and nerve injuries. Practical applications, indications and contraindications are discussed.

Acute Disease↗
PubMed1995

Infarct salvage with liposomal prostaglandin E1 administered by intravenous bolus immediately before reperfusion in a canine infarction-reperfusion model.

BACKGROUND: Prostaglandin E1 (PGE1) inhibits leukocyte and platelet function and reduces infarct size during left atrial infusion. Intravenous liposomal PGE1 (TLC C-53) accelerates thrombolysis and prevents reocclusion in canine coronary thrombosis. We tested the hypothesis that intravenous TLC C-53 would attenuate reperfusion injury in a canine infarction-reperfusion model. METHODS AND RESULTS: Twenty-one open-chest dogs were randomized to receive a 10-minute intravenous infusion of either liposome diluent (placebo), free PGE1 (2 micrograms/kg), or TLC C-53 (2 micrograms/kg PGE1) after 2 hours of left anterior descending (LAD) occlusion just before reperfusion. Hemodynamic assessment, regional myocardial blood flow determination with radioactive microspheres, myocardial leukocyte infiltration by myeloperoxidase assay, and estimation of infarct size using triphenyl tetrazolium chloride staining were performed. Regional fractional shortening was measured with sonomicrometer crystals implanted in the midmyocardium. Infarct size as a percentage of the risk region was significantly reduced (P < .05) with TLC C-53 (37.9 +/- 17.4%) compared with PGE1 (56.7 +/- 13.9%) or placebo (58.0 +/- 9.9%) infusion. Infarct salvage with TLC C-53 was independent of collateral blood flow by ANCOVA. There was a dramatic reduction in myeloperoxidase activity in the infarct, risk, and border regions of dogs treated with TLC C-53 compared with placebo. Enzyme activity was also significantly reduced (P < .05) in the infarct zone with TLC C-53 (0.11 +/- 0.1 U/100 mg) treatment compared with PGE1 (0.38 +/- 0.3 U/100 mg). No significant differences in regional myocardial blood flow or myocardial function among treatment groups were identified, although there was a trend toward improved function in the TLC C-53 dogs. CONCLUSIONS: Bolus intravenous administration of TLC C-53 immediately before reperfusion results in reduced leukocyte infiltration and substantial infarct salvage. TLC C-53 mah be useful in limiting reperfusion injury during treatment of acute myocardial infarction.

Alprostadil↗
PubMed1994

Enhanced thrombolysis, reduced coronary reocclusion and limitation of infarct size with liposomal prostaglandin E1 in a canine thrombolysis model.

OBJECTIVES: The purpose of this study was to test the hypothesis that liposomal prostaglandin E1 (TLC C-53) would result in more rapid thrombolysis, less reocclusion and smaller infarct size when administered with heparin and streptokinase in a canine thrombolysis model. BACKGROUND: In experimental animals, prostaglandin E1 has been shown to augment thrombolysis, improve coronary flow and reduce infarct size when infused directly into the left atrium. TLC C-53 is a stable preparation of prostaglandin E1 bound by phospholipid microspheres that produces fewer adverse hemodynamic effects during intravenous use. METHODS: To investigate the effects of TLC C-53 on coronary patency and infarct salvage, we studied 30 conditioned open chest dogs. After coil-induced left anterior descending coronary artery occlusion and 1 h of clot maturation, the dogs were randomly assigned to receive a 10-min intravenous infusion of either TLC C-53 (2 micrograms/kg body weight) or placebo. Both groups then received intravenous heparin and streptokinase. Hemodynamic variables and Doppler coronary flow were monitored, and myocardial blood flow was determined using radioactive microspheres. Infarct size was assessed with triphenyltetrazolium chloride staining. RESULTS: Thrombolysis time was accelerated from 79 +/- 38 to 47 +/- 9 min (mean +/- SD), and coronary patency was greater (100% vs. 50%) with TLC C-53 than with placebo (p < 0.05). Moreover, for arteries that recanalized, coronary Doppler flow and myocardial perfusion were more severely impaired with placebo. Infarct size as a percent of the area at risk was higher (p < 0.05) with placebo (51 +/- 15%) than with TLC C-53 (33 +/- 14%). Neutrophil infiltration into ischemic myocardium determined by myeloperoxidase assay was also significantly greater in the placebo group. CONCLUSIONS: TLC C-53 administered intravenously before thrombolytic therapy resulted in a significant acceleration of thrombolysis time, improvement in coronary patency and blood flow during reperfusion and a reduction in infarct size.

Alprostadil↗