Socioeconomic differences in food purchasing behaviour and suggested implications for diet-related health promotion

BACKGROUND

The relationship between socioeconomic position (SEP) and diet has been examined mainly on the basis of food and nutrient intake. As a complement to this work, we focused on the socioeconomic patterning of food purchasing, as many educational dietary messages emphasize behaviours such as food choice when shopping. Also, the type of food people buy influences the quality of their nutrient intake.

METHODS

A probability sample of households in Brisbane City, Australia (n = 1003, 66.4% response rate). Data were collected using face-to-face interviews. SEP was measured using education, occupation and household income. Food purchasing was examined on the basis of grocery items (including meat and chicken) and fruit and vegetables.

RESULTS

Significant associations were found between each socioeconomic indicator and food purchasing. Persons from socioeconomically disadvantaged backgrounds were less likely to purchase grocery foods that were comparatively high in fibre and low in fat, salt and sugar. The least educated, those employed in blue-collar (manual) occupations and residents of low income households purchased fewer types of fruit and vegetables, and less regularly, than their higher status counterparts.

CONCLUSIONS

Health promotion efforts aimed at narrowing socioeconomic differences in food purchasing need to be designed and implemented with an understanding of, and a sensitivity to, the barriers to nutritional improvement that difficult life circumstances can impose.

Socioeconomic differences among Australian adults in consumption of fruit and vegetables and intakes of vitamins A, C and folate

OBJECTIVE

To determine whether socioeconomic groups differ in their food intakes for fruit and vegetables, their consumption of fruit and vegetables dense in vitamin A, folate and vitamin C, and their nutrient intakes of vitamin C, folate and vitamin A.

METHODS

The 1995 Australian National Nutrition Survey collected food intake data from 8883 adults aged 18-64 years using a 24-h dietary recall. Fruit and vegetables were measured as amount (g) consumed. Intakes of nutrients were estimated from the 24-h dietary recall data. Participants were categorized by whether or not they consumed fruit or vegetables high in vitamin A, folate and vitamin C. Gross annual household income was used to measure socioeconomic position.

RESULTS

Participants from low-income households consumed a smaller quantity of fruit and vegetables. They were also less likely to consume fruit and vegetables high in vitamin C, folate and vitamin A. Consistent with these findings, men and women from disadvantaged socioeconomic groups had lower intakes of vitamin C and folate compared with their more affluent counterparts. These differences were small to moderate in magnitude. Vitamin A intakes were not significantly related to income.

CONCLUSION

As well as promoting healthy dietary practices, nutrition-promotion strategies should target the nutrient intakes of lower socioeconomic groups. These programmes should focus on improving the quantity and choice of fruit and vegetables consumed by people from low-income households.

Complementary therapy involvement of physicians: implications for practice and learning

OBJECTIVE

We studied physicians' current and desired clinical role functions within the complementary health paradigm and their perceptions of the necessary educational programs to support them.

DESIGN AND SETTING

A questionnaire to determine clinical activities within different complementary therapies was developed and mailed-out to 837 eligible physicians in Hamilton, Ontario, Canada, using a modified Dillman approach.

RESULTS

The overall response rate to the mailed survey was 49.8% (417/837), with response rates of 50.2% (115/229) for family physicians and 49.7% (302/608) for specialists. The amount of interactions around complementary therapies between physicians, their patients and complementary therapists appears to be low. At the same time, there is a growing interest among physicians about complementary therapies, particularly with respect to developing their knowledge about efficacy and enhancing their skills in assessment and counselling.

CONCLUSIONS

The differential levels of acceptance of different therapies by physicians will influence integration of complementary therapies in mainstream medicine.

Variability of Nt-proANP and C-ANP

BACKGROUND

Natriuretic peptides are frequently measured in patients with chronic cardiac failure (CCF). We set out to compare the variability of atrial natriuretic peptide (C-ANP) and its precursor N-terminal pro-ANP (Nt-proANP) to decide which would be more suitable for routine use.

METHODS

Ten males with compensated CCF (age range 62-76 years) were studied, with matched controls. Blood was withdrawn every 2 min for 90 min from a forearm vein, and plasma C-ANP and Nt-proANP were measured by radioimmunoassay.

RESULTS

Levels were elevated in the patient group [C-ANP: median 268 (range 171-423) vs. 40 (28-56) ng L-1, P < 0.0002 Mann-Whitney U-test; Nt-proANP: 1955 (562-4451) vs. 621 (409-961) pmol L-1, P < 0.003]. A similar number of 'peaks' was observed in both groups with both peptides, about one every 10 min, and their relative height was similar in both groups. Variability was greater for C-ANP than for Nt-proANP in both patients [coefficient of variation of means 51 (range 36-70) vs. 3.6 (2.1-6.2)%, P < 0.01; sign test] and controls [65 (49-83) vs. 8.9 (4.7-13.5)%, P < 0.01].

CONCLUSION

Nt-proANP is less variable than C-ANP and hence more suited for diagnostic or prognostic use.

Molecular characterisation of human campylobacteriosis in Northern Ireland: evidence of clonal stability

BACKGROUND

No study has compared Campylobacter isolates from a human source in Northern Ireland over an extended period of time.

AIM

To investigate the clonal stability of thermophilic campylobacters isolated from acute bacterial enteritis in Northern Ireland from 1992 to 1999.

METHODS

Human isolates (n=272), originating from faeces, were characterised at the sub-species level using enterobacterial repetitive intergenic consensus sequence (ERIC2)--random amplification of polymorphic DNA (RAPD) typing.

RESULTS

Thirteen genotypes were identified where three types, namely ERIC A, ERIC C and ERIC I, accounted for 28.3%, 14.3% and 13.6%, respectively. There were no significant associations (p>0.05) between sex, age groupings and year of isolation and ERIC2 genotype, with the exception of ERIC D, which showed a significant decline in isolation with time (p=0.019).

CONCLUSIONS

ERIC genotypes were stable over this period, except genotype C which was lost during this time. Previous molecular typing methods showed campylobacters to be heterogeneous but this study suggests that the local human Campylobacter population consists of several common and stable genotypes. This study has established a database of local ERIC2 genotypes. This methodology may allow the establishment of an all-island database of clinical campylobacters that would be valuable in reducing human campylobacteriosis in Ireland.

CHIP is a U-box-dependent E3 ubiquitin ligase: identification of Hsc70 as a target for ubiquitylation

Proper folding of proteins (either newly synthesized or damaged in response to a stressful event) occurs in a highly regulated fashion. Cytosolic chaperones such as Hsc/Hsp70 are assisted by cofactors that modulate the folding machinery in a positive or negative manner. CHIP (carboxyl terminus of Hsc70-interacting protein) is such a cofactor that interacts with Hsc70 and, in general, attenuates its most well characterized functions. In addition, CHIP accelerates ubiquitin-dependent degradation of chaperone substrates. Using an in vitro ubiquitylation assay with recombinant proteins, we demonstrate that CHIP possesses intrinsic E3 ubiquitin ligase activity and promotes ubiquitylation. This activity is dependent on the carboxyl-terminal U-box. CHIP interacts functionally and physically with the stress-responsive ubiquitin-conjugating enzyme family UBCH5. Surprisingly, a major target of the ubiquitin ligase activity of CHIP is Hsc70 itself. CHIP ubiquitylates Hsc70, primarily with short, noncanonical multiubiquitin chains but has no appreciable effect on steady-state levels or half-life of this protein. This effect may have heretofore unanticipated consequences with regard to the chaperoning activities of Hsc70 or its ability to deliver substrates to the proteasome. These studies demonstrate that CHIP is a bona fide ubiquitin ligase and indicate that U-box-containing proteins may comprise a new family of E3s.

p47phox is required for atherosclerotic lesion progression in ApoE(-/-) mice

NADPH oxidase is upregulated in smooth muscle cells (SMCs) in response to growth factor stimulation, concomitant with increased reactive oxygen species (ROS) production. We investigated the role of ROS production by NADPH oxidase in SMC responses to growth factors and in atherosclerotic lesion formation in ApoE(-/-) mice. SMCs from wild-type, p47phox(-/-), and gp91phox(-/-) mice differed markedly with respect to growth factor responsiveness and ROS generation. p47phox(-/-) SMCs had diminished superoxide production and a decreased proliferative response to growth factors compared with wild-type cells, whereas the response of gp91phox(-/-) SMCs was indistinguishable from that of wild-type SMCs. The relevance of these in vitro observations was tested by measuring atherosclerotic lesion formation in genetically modified (wild-type, p47phox(-/-), ApoE(-/-), and ApoE(-/-)/p47phox(-/-)) mice. ApoE(-/-)/p47phox(-/-) mice had less total lesion area than ApoE(-/-) mice, regardless of whether mice were fed standard chow or a high-fat diet. Together, these studies provide convincing support for the hypothesis that superoxide generation in general, and NADPH oxidase in particular, have a requisite role in atherosclerotic lesion formation, and they provide a rationale for further studies to dissect the contributions of ROS to vascular lesion formation.

Cyclic strain increases protease-activated receptor-1 expression in vascular smooth muscle cells

Cyclic strain regulates many vascular smooth muscle cell (VSMC) functions through changing gene expression. This study investigated the effects of cyclic strain on protease-activated receptor-1 (PAR-1) expression in VSMCs and the possible signaling pathways involved, on the basis of the hypothesis that cyclic strain would enhance PAR-1 expression, reflecting increased thrombin activity. Uniaxial cyclic strain (1 Hz, 20%) of cells cultured on elastic membranes induced a 2-fold increase in both PAR-1 mRNA and protein levels. Functional activity of PAR-1, as assessed by cell proliferation in response to thrombin, was also increased by cyclic strain. In addition, treatment of cells with antioxidants or an NADPH oxidase inhibitor blocked strain-induced PAR-1 expression. Preincubation of cells with protein kinase inhibitors (staurosporine or Ro 31-8220) enhanced strain-increased PAR-1 expression, whereas inhibitors of NO synthase, tyrosine kinase, and mitogen-activated protein kinases had no effect. Cyclic strain in the presence of basic fibroblast growth factor induced PAR-1 mRNA levels beyond the effect of cyclic strain alone, whereas no additive effect was observed between cyclic strain and platelet-derived growth factor-AB. Our findings that cyclic strain upregulates PAR-1 mRNA expression but that shear stress downregulates this gene in VSMCs provide an opportunity to elucidate signaling differences by which VSMCs respond to different mechanical forces.

Vezf1/DB1 is an endothelial cell-specific transcription factor that regulates expression of the endothelin-1 promoter

Coordinated gene regulation within the vascular endothelium is required for normal cardiovascular patterning during development and for vascular homeostasis during adulthood, yet little is known about the mechanisms that regulate endothelial transcriptional events. Vascular endothelial zinc finger 1 (Vezf1)/DB1 is a recently identified zinc finger-containing protein that is expressed specifically within endothelial cells during development. In this report, we demonstrate that Vezf1/DB1 is a nuclear localizing protein that potently and specifically activates transcription mediated by the human endothelin-1 promoter, in a Tax-independent manner, in transient transfection assays. Using a combination of deletion mutagenesis and electrophoretic mobility shift assays, a novel Vezf1/DB1-responsive element was localized to a 6-base pair (bp) motif, ACCCCC, located 47 bp upstream of the endothelin-1 transcription start site. Recombinant Vezf1/DB1 also bound to this sequence, and a 2-bp mutation in this element abolished Vezf1/DB1 responsiveness by the endothelin-1 promoter. Vezf1/DB1 could be identified with a specific antibody in nuclear complexes from endothelial cells that bound to this element. Regulation of endothelin-1 promoter activity by Vezf1/DB1 provides a mechanism for endothelin-1 expression in the vascular endothelium during development and to maintain vascular tone; Vezf1/DB1 itself is a candidate transcription factor for modifying endothelial cell phenotypes in order to appropriately assemble and maintain the cardiovascular system.

Cooperation of a ubiquitin domain protein and an E3 ubiquitin ligase during chaperone/proteasome coupling

BACKGROUND

Molecular chaperones recognize nonnative proteins and orchestrate cellular folding processes in conjunction with regulatory cofactors. However, not every attempt to fold a protein is successful, and misfolded proteins can be directed to the cellular degradation machinery for destruction. Molecular mechanisms underlying the cooperation of molecular chaperones with the degradation machinery remain largely enigmatic so far.

RESULTS

By characterizing the chaperone cofactors BAG-1 and CHIP, we gained insight into the cooperation of the molecular chaperones Hsc70 and Hsp70 with the ubiquitin/proteasome system, a major system for protein degradation in eukaryotic cells. The cofactor CHIP acts as a ubiquitin ligase in the ubiquitination of chaperone substrates such as the raf-1 protein kinase and the glucocorticoid hormone receptor. During targeting of signaling molecules to the proteasome, CHIP may cooperate with BAG-1, a ubiquitin domain protein previously shown to act as a coupling factor between Hsc/Hsp70 and the proteasome. BAG-1 directly interacts with CHIP; it accepts substrates from Hsc/Hsp70 and presents associated proteins to the CHIP ubiquitin conjugation machinery. Consequently, BAG-1 promotes CHIP-induced degradation of the glucocorticoid hormone receptor in vivo.

CONCLUSIONS

The ubiquitin domain protein BAG-1 and the CHIP ubiquitin ligase can cooperate to shift the activity of the Hsc/Hsp70 chaperone system from protein folding to degradation. The chaperone cofactors thus act as key regulators to influence protein quality control.

From the cradle to the grave: molecular chaperones that may choose between folding and degradation

Molecular chaperones are known to facilitate cellular protein folding. They bind non-native proteins and orchestrate the folding process in conjunction with regulatory cofactors that modulate the affinity of the chaperone for its substrate. However, not every attempt to fold a protein is successful and chaperones can direct misfolded proteins to the cellular degradation machinery for destruction. Protein quality control thus appears to involve close cooperation between molecular chaperones and energy-dependent proteases. Molecular mechanisms underlying this interplay have been largely enigmatic so far. Here we present a novel concept for the regulation of the eukaryotic Hsp70 and Hsp90 chaperone systems during protein folding and protein degradation.

Peroxynitrite causes endothelial cell monolayer barrier dysfunction

Nitric oxide (.NO) attenuates hydrogen peroxide (H(2)O(2))-mediated barrier dysfunction in cultured porcine pulmonary artery endothelial cells (PAEC) (Gupta MP, Ober MD, Patterson C, Al-Hassani M, Natarajan V, and Hart, CM. Am J Physiol Lung Cell Mol Physiol 280: L116-L126, 2001). However,.NO rapidly combines with superoxide (O) to form the powerful oxidant peroxynitrite (ONOO(-)), which we hypothesized would cause PAEC monolayer barrier dysfunction. To test this hypothesis, we treated PAEC with ONOO(-) (500 microM) or 3-morpholinosydnonimine hydrochloride (SIN-1; 1-500 microM). SIN-1-mediated ONOO(-) formation was confirmed by monitoring the oxidation of dihydrorhodamine 123 to rhodamine. Both ONOO(-) and SIN-1 increased albumin clearance (P < 0.05) in the absence of cytotoxicity and altered the architecture of the cytoskeletal proteins actin and beta-catenin as detected by immunofluorescent confocal imaging. ONOO(-)-induced barrier dysfunction was partially reversible and was attenuated by cysteine. Both ONOO(-) and SIN-1 nitrated tyrosine residues, including those on beta-catenin and actin, and oxidized proteins in PAEC. The introduction of actin treated with ONOO(-) into PAEC monolayers via liposomes also resulted in barrier dysfunction. These results indicate that ONOO(-) directly alters endothelial cytoskeletal proteins, leading to barrier dysfunction.

Roles for the Rhodobacter sphaeroides CcmA and CcmG proteins

Rhodobacter sphaeroides cells containing an in-frame deletion within ccmA lack detectable soluble and membrane-bound c-type cytochromes and are unable to grow under conditions where these proteins are required. Only strains merodiploid for ccmABCDG were found after attempting to generate cells containing either a ccmG null mutation or a ccmA allele that should be polar on to expression of ccmBCDG, suggesting that CcmG has another important role in R. sphaeroides.

PTP-epsilon, a tyrosine phosphatase expressed in endothelium, negatively regulates endothelial cell proliferation

The vascular endothelium is a dynamic interface between the blood vessel and circulating factors and, as such, plays a critical role in vascular events like inflammation, angiogenesis, and hemostasis. Whereas specific protein tyrosine kinases have been identified in these processes, less is known about their protein tyrosine phosphatase (PTP) counterparts. We utilized a RT-PCR/differential hybridization assay to identify PTP-epsilon as a highly abundant endothelial cell PTP. PTP-epsilon mRNA expression is growth factor responsive, suggesting a role for this enzyme in endothelial cell proliferation. Overexpression of PTP-epsilon decreases proliferation by 60% in human umbilical vein endothelial cells (HUVEC) but not in smooth muscle cells or fibroblasts. In contrast, overexpression of PTP-epsilon (D284A), a catalytically inactive mutant, has no significant effect on HUVEC proliferation. These data provide the first functional characterization of PTP-epsilon in endothelial cells and identify a novel pathway that negatively regulates endothelial cell growth. Such a pathway may have important implications in vascular development and angiogenesis.

Cell cycle in vasculoproliferative diseases: potential interventions and routes of delivery

Atherosclerosis and restenosis of epicardial vessels are among the greatest challenges facing the clinical cardiologist, and phenotypic modulation and proliferation of smooth muscle cells are major components of the vasculoproliferative response. Proliferation is regulated by the interplay of regulatory proteins at checkpoints in the cell cycle that alter cellular growth. Activation of the cell cycle and the genetic control of its progression are final common pathways in this process. Investigators have postulated that cell-cycle inhibition using drugs and genetic or physical methods has the potential to reverse or prevent the vasculoproliferative process. The current challenge is to translate in vitro data demonstrating the efficacy of cell-cycle inhibition to clinical trials. At present, the steps that must be taken to meet this goal are (1) to design methods of delivery of these agents to specific sites, (2) to identify appropriate cellular targets to elicit cell-cycle arrest, and (3) to improve the therapeutic ratio by minimizing potential side effects. This review discusses current concepts of the cell cycle, target-regulating mechanisms, and possible interventions in vasculoproliferative diseases. We also discuss ongoing clinical trials that use antiproliferative agents in the hope of limiting the course of these diseases, as well as the promise that antiproliferative therapy holds in the coming decade.

New tricks for old dogs: nonthrombotic effects of thrombin in vessel wall biology

Thrombin is a serine protease that potently activates platelets and catalyzes the conversion of fibrinogen to fibrin. Thrombin also exerts direct effects on vascular cells, such as smooth muscle cells, via interactions with members of the protease-activated receptor family. Evidence in several animal models implicates thrombin-mediated signaling events in the response to injury that typifies vascular lesion formation in atherosclerosis and restenosis. In this review, we examine the activation of protease-activated receptors by thrombin, the downstream signaling events mediated by these receptors, and the physiological role of thrombin in vascular cells and vascular disease.

Aging, oxidative responses, and proliferative capacity in cultured mouse aortic smooth muscle cells

The cellular mechanisms that contribute to the acceleration of atherosclerosis in aging populations are poorly understood, although it is hypothesized that changes in the proliferative capacity of vascular smooth muscle cells is contributory. We addressed the relationship among aging, generation of reactive oxygen species (ROS), and proliferation in primary culture smooth muscle cells (SMC) derived from the aortas of young (4 mo old) and aged (16 mo old) mice to understand the phenotypic modulation of these cells as aging occurs. SMC from aged mice had decreased proliferative capacity in response to α-thrombin stimulation, yet generated higher levels of ROS and had constitutively increased mitogen-activated protein kinase activity, in comparison with cells from younger mice. These effects may be explained by dysregulation of cell cycle-associated proteins such as cyclin D1 and p27Kip1 in SMC from aged mice. Increased ROS generation was associated with decreased endogenous antioxidant activity, increased lipid peroxidation, and mitochondrial DNA damage. Accrual of oxidant-induced damage and decreased proliferative capacity in SMC may explain, in part, the age-associated transition to plaque instability in humans with atherosclerosis.

Thrombin regulates vascular smooth muscle cell growth and heat shock proteins via the JAK-STAT pathway

The growth-stimulating effects of thrombin are mediated primarily via activation of a G protein-coupled receptor, PAR-1. Because PAR-1 has no intrinsic tyrosine kinase activity, yet requires tyrosine phosphorylation events to induce mitogenesis, we investigated the role of the Janus tyrosine kinases (JAKs) in thrombin-mediated signaling. JAK2 was activated rapidly in rat vascular smooth muscle cells (VSMC) treated with thrombin, and signal transducers and activators of transcription (STAT1 and STAT3) were phosphorylated and translocated to the nucleus in a JAK2-dependent manner. AG-490, a JAK2-specific inhibitor, and a dominant negative JAK2 mutant inhibited thrombin-induced ERK2 activity and VSMC proliferation suggesting that JAK2 is upstream of the Ras/Raf/MEK/ERK pathway. To elucidate the functional significance of JAK-STAT activation, we studied the effect of thrombin on heat shock protein (Hsp) expression, based upon the following: 1) reports that thrombin stimulates reactive oxygen species production in VSMC; 2) the putative role of Hsps in modulating cellular responses to reactive oxygen species; and 3) the presence of functional STAT1/3-binding sites in Hsp70 and Hsp90beta promoters. Indeed, thrombin up-regulated Hsp70 and Hsp90 protein expression via enhanced binding of STATs to cognate binding sites in the Hsp70 and Hsp90 promoters. Together, these results suggest that JAK-STAT pathway activation is necessary for thrombin-induced VSMC growth and Hsp gene expression.

[Current topics in vascular biology: an update for the 21st century]

Although taken for granted in the present day, the central role played by the blood vessels themselves in regulating the cardiovascular system under physiologic and pathologic conditions has only been understood in the last several decades. The field of vascular biology grew out of this appreciation of the primacy of the vasculature in cardiovascular pathologies. In this review, we come up to date on several topics of particular interest to the field of vascular biology as it enters the 21st century: namely, the role of oxidative stress in vascular function and dysfunction; angiogenesis and angiogenic gene therapies; and emerging biomarkers of atherosclerosis. Each of these areas is likely to experience significant advances in the coming years that will directly impact clinical decision-making and care of patients with cardiovascular diseases.