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Biomedical subjects

Carroll E Cross

Publications and source records attributed to Carroll E Cross.

At least 19 recordsLinked to original sources
PubMed2007

The use of Raman microscopy to determine and localize vitamin E in biological samples.

Alpha-tocopherol (aT), the predominant form of vitamin E in mammals, is thought to prevent oxidation of polyunsaturated fatty acids. In the lung, aT is perceived to be accumulated in alveolar type II cells and secreted together with surfactant into the epithelial lining fluid. Conventionally, determination of aT and related compounds requires extraction with organic solvents. This study describes a new method to determine and image the distribution of aT and related compounds within cells and tissue sections using the light-scattering technique of Raman microscopy to enable high spatial as well as spectral resolution. This study compared the nondestructive analysis by Raman microscopy of vitamin E, in particular aT, in biological samples with data obtained using conventional HPLC analysis. Raman spectra were acquired at spatial resolutions of 2-0.8 microm. Multivariate analysis techniques were used for analyses and construction of corresponding maps showing the distribution of aT, alpha-tocopherol quinone (aTQ), and other constituents (hemes, proteins, DNA, and surfactant lipids). A combination of images enabled identification of colocalized constituents (heme/aTQ and aT/surfactant lipids). Our data demonstrate the ability of Raman microscopy to discriminate between different tocopherols and oxidation products in biological specimens without sample destruction. By enabling the visualization of lipid-protein interactions, Raman microscopy offers a novel method of investigating biological characterization of lipid-soluble compounds, including those that may be embedded in biological membranes such as aT.

Antioxidants↗
PubMed2007

Genome wide responses of murine lungs to dietary alpha-tocopherol.

Alpha-tocopherol (alpha-T) may affect biological processes by modulating mRNA concentrations. This study screened the responses of approximately 15,000 lung mRNAs to dietary alpha-T in mice. The lung was chosen as the target organ because it is subjected to cyclical variations in oxidant and inflammatory stressors and alpha-T has been implicated in their modulations. The analysis identified approximately 400 mRNAs sensitive to alpha-T status of lungs determined by dietary alpha-T. The female lung transcriptome appears to be more sensitive to the alpha-T status than that of the male lungs. Here, we focus on the induction of 13 cytoskeleton genes by dietary alpha-T because they were similarly induced in the male and the female lungs. Their inductions were confirmed by quantitative-real-time-polymerase chain reaction (qRT-PCR). Immunohistochemical analyses of three of the encoded proteins suggest that they are expressed in lung vasculature and alveolar regions. The data suggest that the lung alpha-T status may modulate cytoarchitecture of lungs.

Animals↗
PubMed2006

Antioxidants in cystic fibrosis. Conclusions from the CF antioxidant workshop, Bethesda, Maryland, November 11-12, 2003.

Although great strides are being made in the care of individuals with cystic fibrosis (CF), this condition remains the most common fatal hereditary disease in North America. Numerous links exist between progression of CF lung disease and oxidative stress. The defect in CF is the loss of function of the transmembrane conductance regulator (CFTR) protein; recent evidence that CFTR expression and function are modulated by oxidative stress suggests that the loss may result in a poor adaptive response to oxidants. Pancreatic insufficiency in CF also increases susceptibility to deficiencies in lipophilic antioxidants. Finally the airway infection and inflammatory processes in the CF lung are potential sources of oxidants that can affect normal airway physiology and contribute to the mechanisms causing characteristic changes associated with bronchiectasis and loss of lung function. These multiple abnormalities in the oxidant/antioxidant balance raise several possibilities for therapeutic interventions that must be carefully assessed.

Animals↗
PubMed2006

Does gamma-tocopherol play a role in the primary prevention of heart disease and cancer? A review.

Vitamin E consists of a group of eight isomers, four tocopherols (alpha-, beta-, gamma-, delta-tocopherol) and four tocotrienols (alpha-, beta-, gamma-, delta-tocotrienol). While extensive literature has been published on the potential health benefits of alpha-tocopherol, little is known about gamma-tocopherol, the major form of vitamin E in food in the U.S. gamma-tocopherol has recently received more research attention based on findings from in vitro and animal studies indicating that it has potent anti-inflammatory and antioxidant properties. Based on these recent studies, it is important to investigate the possible health benefits of gamma-tocopherol in humans. In this article, we review publications on dietary gamma-tocopherol intake, plasma gamma-tocopherol levels, cardiovascular disease and cancer risk in humans.

Diet↗
PubMed2005

Are Drosophila a useful model for understanding the toxicity of inhaled oxidative pollutants: a review.

Oxidative atmospheric pollutants represent a significant stress and cause injury to both vertebrate and invertebrate species. In both, the biosurfaces of their respiratory apparatus are directly exposed to oxidizing pollutant-induced stresses. Respiratory-tract surfaces contain integrated antioxidant systems that appear to provide a primary defense against environmental insults caused by inhaled atmospheric reactive oxygen species (ROS) and reactive nitrogen species (RNS), whether gaseous or particulate. When the biosurface antioxidant defenses are overwhelmed, oxidative and nitrosative stress to the acellular and cellular components of the exposed biosurfaces can ensue via direct chemical reactions that lead to the induction of inflammatory, adaptive, injurious, and reparative processes. The study of model invertebrates (e.g., Drosophila) has a long history of yielding valuable insights into both fundamental biology and pathobiology. Mutants and/or transgenic insects, with specific alterations in key components of innate and/or adaptive antioxidant defense systems and immune genes, offer opportunities to dissect the complex systems that maintain respiratory tract surface defenses against environmental oxidants and the ensuing host responses. In this article, we use a comparative absfont approach to consider interactions of atmospheric oxidant pollutants with selected biosystems. We focused primarily on ozone (O(3)) as the pollutant, vertebrate and invertebrate respiratory tracts as the exposed biosystems, and nonenzymatic micronutrient antioxidants as significant contributors to overall antioxidant defense strategies. We present parallels among these diverse organisms with regard to their protective strategies against environmental atmospheric oxidants, with particular focus given to using the invertebrate Drosophila as a potentially useful model for vertebrate respiratory-tract responses to inhaled oxidants specifically and pollutants in general. We conclude that the insect respiratory system has considerable promise toward understanding novel aspects of vertebrate respiratory tract responses to inhaled oxidative environmental challenges.

Air Pollutants↗
PubMed2005

Modulation of cutaneous wound healing by ozone: differences between young and aged mice.

Cutaneous tissues are frequently exposed to prooxidative environments, including UV radiation and air pollutants. Among the latter, ozone (O(3)) is of particular concern because of its high and dominating presence in photochemical smog. It is well known that O(3) depletes small molecular weight antioxidants, oxidizes proteins, induces lipid peroxidation and activates cellular responses in various tissues. Using an in vivo model (SKH-1 hairless mice), the interaction between O(3) exposure (0.5ppmx6h/day) and age was examined in relation to cutaneous wound healing. Compared to younger (8 weeks) mice, older (18 months) mice exposed to O(3) (day 0 to day 9 after wounding) exhibited delayed wound closure, increased lipid peroxidation (measured as 4-HNE protein adducts) and protein oxidation (measured as carbonyls concentration) and decreased levels of P-IkappaBalpha and TGFbeta protein. These findings support the hypothesis that oxidant pollutant exposure and age interact so as to disrupt normal wound healing processes.

Aging↗
PubMed2005

Studies in humans using deuterium-labeled alpha- and gamma-tocopherols demonstrate faster plasma gamma-tocopherol disappearance and greater gamma-metabolite production.

We hypothesized that human plasma alpha- and gamma-tocopherol concentrations reflect differences in their kinetics, especially influenced by gamma-tocopherol metabolism. Vitamin E kinetics were evaluated in humans (n=14) using approximately 50 mg each of an equimolar ratio of d6-alpha- and d2-gamma-tocopheryl acetates administered orally. Mass spectrometry was used to measure deuterated plasma tocopherols, as well as plasma and urinary vitamin E metabolites, alpha- and gamma-carboxyethylhydroxychromans (CEHCs). Plasma d2-gamma-tocopherol fractional disappearance rates (FDR; 1.39+/-0.44 pools/day, mean+/-SD) were more than three times greater than those of d6-alpha-tocopherol (0.33+/-0.11, p<0.001). The d2-gamma-tocopherol half-life was 13+/-4 h compared with 57+/-19 for d6-alpha-tocopherol. Whereas neither plasma nor urinary d6-alpha-CEHC was detectable (limit of detection 1 nmol/L), gamma-CEHC (labeled plus unlabeled) increased from 129+/-20 to 258+/-40 nmol/L by 12 h and returned to baseline by 48 h; at 12 h d2-gamma-CEHC represented 54+/-4% of plasma gamma-CEHC. Women compared with men had a greater d2-gamma-tocopherol FDR (p<0.004) and a greater maximal plasma d2-gamma-CEHC concentration (p<0.02) and CEHC FDR (p<0.007), as well as excreting four times as much d2-gamma-CEHC (p<0.04) in urine. Thus, gamma-tocopherol is rapidly metabolized to gamma-CEHC, and to a greater degree in women than in men, whereas alpha-tocopherol is maintained in the plasma and little is metabolized to alpha-CEHC.

Adult↗
PubMed2005

Alpha-tocopherol modulates Cyp3a expression, increases gamma-CEHC production, and limits tissue gamma-tocopherol accumulation in mice fed high gamma-tocopherol diets.

Although all forms of vitamin E are absorbed, the liver preferentially secretes alpha-, but not gamma-tocopherol, into plasma. Liver alpha-tocopherol secretion is under the control of the alpha-tocopherol transfer protein (TTP). Therefore, to assess gamma-tocopherol bioactivities Ttpa-/-, +/- and +/+ mice were fed for 5 weeks diets containing gamma-tocopherol 550 (gamma-T550), gamma-tocopherol 60 (gamma-T60) mg/kg that also contained trace amounts of alpha-tocopherol, a vitamin E-deficient diet, or a control diet. Plasma and tissues from mice fed gamma-T550 diets were found to contain similar gamma- and alpha-tocopherol concentrations despite the high dietary gamma-tocopherol content; nervous tissues contained almost no gamma-tocopherol. Liver vitamin E metabolites (carboxyethyl hydroxychromans, CEHCs) were also measured. In mice with widely ranging liver alpha- (from 0.7 to 16 nmol/g) and gamma-tocopherol concentrations (0 to 13 nmol/g), hepatic alpha-CEHC was undetectable, but gamma-CEHC concentrations (0.1 to 0.8 nmol/g) were correlated with both alpha- and gamma-tocopherol concentrations (P < 0.004). Hepatic cytochrome P450s (CYPs) involved in vitamin E metabolism, Cyp4f and Cyp3a, were also measured. There were no variations in Cyp4f protein expression as related to diet or mouse genotype. However, Cyp3a was correlated (P < 0.0001) with liver alpha-, but not gamma-tocopherol concentrations. These data support the hypothesis that alpha-tocopherol modulates xenobiotic metabolism by increasing Cyp3a expression, gamma-CEHC formation, and the excretion of both gamma-tocopherol and gamma-CEHC.

Animal Feed↗
PubMed2004

Ascorbic acid in nasal and tracheobronchial airway lining fluids.

Ascorbic acid (AA) is thought to be an important antioxidant in the respiratory tract, whose regulation is yet to be fully characterized. We investigated whether AA in respiratory tract lining fluids (RTLFs) can be augmented by oral supplementation with AA. Plasma, nasal lavage fluids (NLFs), induced sputum (IS), and saliva were analyzed for AA immediately before and 2 h after ingestion of 2 g of AA in 13 healthy subjects. Concentrations of AA (median and range) were 52.5 (16.0-88.5), 2.4 (0.18-4.66), 2.4 (0.18-6.00), and 0.55 (0.18-18.90) micromol/l, respectively. Two hours after ingestion of AA, plasma AA increased 2-fold (p = .004), NLF AA increased 3-fold (p = .039), but IS and saliva AA did not increase. As AA concentrations in saliva and tracheobronchial secretions were low compared with other common extracellular components (such as urate), we evaluated the fate of AA in these fluids. Addition of AA to freshly obtained saliva or IS resulted in rapid depletion, which could be largely prevented or reversed by sodium azide or dithiothreitol. These findings suggest that oxidant-producing systems in saliva and airway secretions, such as heme peroxidases and other oxidizing substances, rapidly consume AA. Whereas oral supplementation resulted in detectable increases of AA in NLFs, its levels in tracheobronchial lining fluid, as measured by IS, were unaffected and remained relatively low, suggesting that AA may play a less significant antioxidant role in this compartment as compared with most other extracellular compartments.

Administration, Oral↗
PubMed2004

Tissue-specific gene expression of prolactin receptor in the acute-phase response induced by lipopolysaccharides.

Acute inflammation can elicit a defense reaction known as the acute-phase response (APR) that is crucial for reestablishing homeostasis in the host. The role for prolactin (PRL) as an immunomodulatory factor maintaining homeostasis under conditions of stress has been proposed; however, its function during the APR remains unclear. Previously, it was shown that proinflammatory cytokines characteristic of the APR (TNF-alpha, IL-1beta, and IFNgamma) induced the expression of the PRL receptor (PRLR) by pulmonary fibroblasts in vitro. Here, we investigated the in vivo expression of PRLR during lipopolysaccharide (LPS)-induced APR in various tissues of the mouse. We show that PRLR mRNA and protein levels were downregulated in hepatic tissues after intraperitoneal LPS injection. Downregulation of PRLR in the liver was confirmed by immunohistochemistry. A suppressive effect on mRNA expression was also observed in prostate, seminal vesicle, kidney, heart, and lung tissues. However, PRLR mRNA levels were increased in the thymus, and no changes were observed in the spleen. The proportion of transcripts for the different receptor isoforms (long, S1, S2, and S3) in liver and thymus was not altered by LPS injection. These findings suggest a complex tissue-specific regulation of PRLR expression in the context of the APR.

Acute-Phase Reaction↗
PubMed2004

Enhanced inflammatory responses in alpha-tocopherol transfer protein null mice.

The liver preferentially secretes alpha-tocopherol into plasma under the control of the hepatic alpha-tocopherol transfer protein (alpha-TTP). alpha-TTP-null mice (Ttpa(-/-) mice) are vitamin E deficient, therefore were used for investigations of in vivo responses to sub-normal tissue alpha-tocopherol concentrations during inflammation. Increased basal oxidative stress in Ttpa(-/-) mice was documented by increased plasma lipid peroxidation, and superoxide production by bone marrow-derived neutrophils stimulated in vitro with phorbol 12-myristate 13-acetate. Lipopolysaccharide (LPS) injected intraperitoneally induced increases in lung and liver HO-1 and iNOS, as well as plasma NO(x) in Ttpa(+/+) mice. LPS induced more modest increases in these markers in Ttpa(-/-) mice, while more marked increases in plasma IL-10 and lung lavage TNF alpha were observed. Taken together, these results demonstrate that alpha-tocopherol is important for proper modulation of inflammatory responses and that sub-optimal alpha-tocopherol concentrations may derange inflammatory-immune responses.

Animals↗
PubMed2004

In vivo ozone exposure induces antioxidant/stress-related responses in murine lung and skin.

Lung and skin are the organs directly exposed to environmental pollution. Ozone (O(3)) is a toxic, oxidant air pollutant, and exposure has been shown to induce antioxidant depletion as well as oxidation of lipids and proteins within the outermost skin layer (stratum corneum) and the lung respiratory tract lining fluids (RTLFs). To further define skin and lung responses to O(3) exposure, SKH-1 hairless mice were exposed to either 0.8 ppm of O(3) (a level occasionally reached in very polluted areas) or ambient air 6 h/day for 6 consecutive days. O(3) exposure resulted in the depletion of alpha-tocopherol in lung and plasma and induction in both skin and lung of heme oxygenase 1, cyclooxygenase 2, and proliferating cell nuclear antigen. O(3)-exposed animals showed a similar extent of upregulation of COX-2 and PCNA in lung and skin, whereas HO-1 was more responsive in skin than in lung (7-fold induction vs. 2-fold induction). In addition to these measures of response to oxidative stress, O(3) exposure led to the activation of nuclear factor kappaB measured as IkappaBalpha phosphorylation in both tissues. We conclude that in this model, O(3) at high pollutant levels is able to affect both lung and skin biology, inducing depletion of alpha-tocopherol and inducing stress-related responses in both skin epidermis and respiratory tract epithelium.

Air Pollution↗
PubMed2004

Lutein, zeaxanthin, macular pigment, and visual function in adult cystic fibrosis patients.

BACKGROUND: Pancreatic insufficiency in cystic fibrosis (CF), even with replacement pancreatic enzyme therapy, is often associated with decreased carotenoid absorption. Because the macular pigment of the retina is largely derived from 2 carotenoids, lutein and zeaxanthin, the decreased serum concentrations seen in CF may have consequences for ocular and retinal health OBJECTIVES: Our aims were to determine plasma carotenoid concentrations, determine absorption and distribution of macular pigment, and assess retinal health and visual function in CF patients. DESIGN: In 10 adult CF patients (ages 21-47 y) and 10 age- and sex-matched healthy control subjects, we measured macular pigment density in vivo, measured serum lutein and zeaxanthin concentrations, and comprehensively assessed visual performance (including contrast sensitivity, color discrimination, and retinal function) under conditions of daylight illumination. RESULTS: Serum lutein and zeaxanthin were significantly reduced (P < 0.005) in CF patients ( +/- SD: 87 +/- 36.1 and 27 +/- 15.8 nmol/L, respectively) compared with control subjects (190 +/- 72.1 and 75 +/- 23.6 nmol/L, respectively). Although macular pigment optical density was significantly lower (P < 0.0001) in the CF group (0.24 +/- 0.11) than in the control group (0.53 +/- 0.12), no significant differences in visual function were observed. CONCLUSIONS: Adults with CF have dramatically low serum and macular concentrations of carotenoids (lutein and zeaxanthin), but their ocular status and visual function are surprisingly good. The clinical implications of low plasma concentrations of carotenoids in CF are yet to be clarified.

Adult↗
PubMed2004

Alpha-tocopherol transfer protein deficiency in mice causes multi-organ deregulation of gene networks and behavioral deficits with age.

Functions of alpha-tocopherol (alpha-T) in vivo, other than those for fertility in females, are intensely debated. The discovery of alpha-T deficiency in patients with ataxia (AVED) followed by the identification of mutations in the gene encoding alpha-tocopherol transfer protein (TTP) in AVED patients demonstrates an essential role of alpha-T and TTP for normal neurological function. alpha-T molecular targets that account for alpha-T-sensitive neurological dysfunction remain to be discovered. We have used high-density oligonucleotide arrays to search for putative alpha-T-sensitive genes in the CNS and other tissues in an in vivo model of alpha-T deficiency imposed at birth by the deletion of the TTP gene in mice. Repression of genes affecting synaptic function and myelination and induction of genes for neurodegeneration in the motor cortex of alpha-T-deficient mice were identified. The expression of retinoic acid-related orphan receptor alpha (ROR-alpha) was repressed in the cortex and adrenal glands of TTP-deficient mice. Deficiency of ROR-alpha causes ataxia in mice and may account for ataxia in AVED patients. These observations suggest that some of the actions of alpha-T are mediated by the transcription factor ROR-alpha. The behavior of young TTP-null mice was essentially normal, but older mice showed inactivity, ataxia, and memory dysfunction. mRNA profiles of old alpha-T-deficient cerebral cortices are compatible with repressed activity of oligodendrocytes and astrocytes. In conclusion, gene-expression profiling studies have identified novel alpha-T-modulated genes and cells in the CNS that may be causatively linked with delayed neurodegeneration and age-related decline in behavioral repertoires.

Aging↗