The 43-kD polypeptide of heart gap junctions: immunolocalization, topology, and functional domains

Analysis by SDS-PAGE of gap junction fractions isolated from heart suggests that the junctions are comprised of a protein with an Mr 43,000. Antibodies against the electroeluted protein and a peptide representing the 20 amino terminal residues bind specifically on immunoblots to the 43-kD protein and to the major products arising from proteolysis during isolation. By immunocytochemistry, the protein is found in ventricle and atrium in patterns consistent with the known distribution of gap junctions. Both antibodies bind exclusively to gap junctions in fractions from heart examined by EM after gold labeling. Since only domains of the protein exposed at the cytoplasmic surface should be accessible to antibody, we conclude that the 43-kD protein is assembled in gap junctions with the amino terminus of the molecule exposed on the cytoplasmic side of the bilayer, that is, on the same side as the carboxy terminus as determined previously. By combining proteolysis experiments with data from immunoblotting, we can identify a third cytoplasmic region, a loop of some 4 kD between membrane protected domains. This loop carries an antibody binding site. The protein, if transmembrane, is therefore likely to cross the membrane four times. We have used the same antisera to ascertain if the 43-kD protein is involved in cell-cell communication. The antiserum against the amino terminus blocked dye coupling in 90% of cell pairs tested; the antiserum recognizing epitopes in the cytoplasmic loop and cytoplasmic tail blocked coupling in 75% of cell pairs tested. Preimmune serum and control antibodies (one against MIP and another binding to a cardiac G protein) had no or little effect on dye transfer. Our experimental evidence thus indicates that, in spite of the differences in amino acid sequence, the gap junction proteins in heart and liver share a general organizational plan and that there may be several domains (including the amino terminus) of the molecule that are involved in the control of junctional permeability

Development of a Tuned Interfacial Force Field Parameter Set for the Simulation of Protein Adsorption to Silica Glass

Adsorption free energies for eight host–guest peptides (TGTG-X-GTGT, with X = N, D, G, K, F, T, W, and V) on two different silica surfaces [quartz (100) and silica glass] were calculated using umbrella sampling and replica exchange molecular dynamics and compared with experimental values determined by atomic force microscopy. Using the CHARMM force field, adsorption free energies were found to be overestimated (i.e., too strongly adsorbing) by about 5–9 kcal/mol compared to the experimental data for both types of silica surfaces. Peptide adsorption behavior for the silica glass surface was then adjusted using a modified version of the CHARMM program, which we call dual force-field CHARMM, which allows separate sets of nonbonded parameters (i.e., partial charge and Lennard-Jones parameters) to be used to represent intra-phase and inter-phase interactions within a given molecular system. Using this program, interfacial force field (IFF) parameters for the peptide-silica glass systems were corrected to obtain adsorption free energies within about 0.5 kcal/mol of their respective experimental values, while IFF tuning for the quartz (100) surface remains for future work. The tuned IFF parameter set for silica glass will subsequently be used for simulations of protein adsorption behavior on silica glass with greater confidence in the balance between relative adsorption affinities of amino acid residues and the aqueous solution for the silica glass surface

State Anxiety Is Associated with Cardiovascular Reactivity in Young, Healthy African Americans

Although several studies have shown that enhanced cardiovascular reactivity can predict hypertension development in African Americans, these findings have not been consistent among all studies examining reactivity and hypertension susceptibility. This inconsistency may be explained by the influence of anxiety (state and trait) on the blood pressure response to stress. Therefore, this study sought to determine whether anxiety is associated with blood pressure response to cold pressor (CP) and anger recall (AR) stress tests in young healthy African Americans. Modeling using state and trait anxiety revealed that state anxiety predicts systolic (SBP) and diastolic blood pressure DBP response to CP and AR (P ≤ 0.02). Interestingly, state anxiety predicted heart rate changes only to CP (P < 0.01; P = 0.3 for AR). Although trait anxiety was associated with SBP response to AR and not CP, it was not a significant predictor of reactivity in our models. We conclude that anxiety levels may contribute to the variable blood pressure response to acute stressors and, therefore, should be assessed when performing cardiovascular reactivity measures

Design and Vertical Tests of SPS-series Double-Quarter Wave (DQW) Cavity Prototypes for the HL-LHC Crab Cavity System

Crab crossing is essential for high-luminosity colliders. The High Luminosity Large Hadron Collider (HL-LHC) will equip one of its Interaction Points (IP1) with Double-Quarter Wave (DQW) crab cavities. A DQW cavity is a new generation of deflecting RF cavities that stands out for its compactness and broad frequency separation between fundamental and first high-order modes. The deflecting kick is provided by its fundamental mode. Each HL-LHC DQW cavity shall provide a nominal deflecting voltage of 3.4 MV, although up to 5.0 MV may be required. A Proof-of-Principle (PoP) DQW cavity was limited by quench at 4.6 MV. This paper describes a new, highly optimized cavity, designated DQW SPS-series, which satisfies dimensional, cryogenic, manufacturing and impedance requirements for beam tests at SPS and operation in LHC. Two prototypes of this DQW SPS-series were fabricated by US industry and cold tested after following conventional SRF surface treatment. Both units outperformed the PoP cavity, reaching a deflecting voltage of 5.3-5.9 MV. This voltage - the highest reached by a DQW cavity - is well beyond the nominal voltage of 3.4 MV and may even operate at the ultimate voltage of 5.0MVwith sufficient margin. This paper covers fabrication, surface preparation and cryogenic RF test results and implications

Population-based Interventions Engaging Communities of Color in Healthy Eating and Active Living: A Review

INTRODUCTION: The U.S. obesity epidemic is escalating, particularly among communities of color. Obesity control efforts have shifted away from individual-level approaches toward population-based approaches that address socio-cultural, political, economic, and physical environmental factors. Few data exist for ethnic minority groups. This article reviews studies of population-based interventions targeting communities of color or including sufficient samples to permit ethnic-specific analyses. METHODS: Inclusion criteria were established, an electronic database search conducted, and non-electronically catalogued studies retrieved. Findings were aggregated for earlier (early 1970s to early 1990s) and later (mid-1990s to present) interventions. RESULTS: The search yielded 23 ethnically inclusive intervention studies published between January 1970 and May 2003. Several characteristics of inclusive interventions were consistent with characteristics of community-level interventions among predominantly white European-American samples: use of non-interpersonal channels for information dissemination directed at broad spheres of influence (e.g., mass media), promotion of physical activity, and incorporation of social marketing principles. Ethnically inclusive studies, however, also placed greater emphasis on involving communities and building coalitions from study inception; targeting captive audiences; mobilizing social networks; and tailoring culturally specific messages and messengers. Inclusive studies also focused more on community than individual norms. Later studies used "upstream" approaches more than earlier studies. Fewer than half of the inclusive studies presented outcome evaluation data. Statistically significant effects were few and modest, but several studies demonstrated better outcomes among ethnic minority than white participants sampled. CONCLUSION: The best data available speak more about how to engage and retain people of color in these interventions than about how to create and sustain weight loss, regular engagement in physical activity, or improved diet. Advocacy should be directed at increasing the visibility and budget priority of interventions, particularly at the state and local levels

Enzyme Sequence and Its Relationship to Hyperbaric Stability of Artificial and Natural Fish Lactate Dehydrogenases

The cDNAs of lactate dehydrogenase b (LDH-b) from both deep-sea and shallow living fish species, Corphaenoides armatus and Gadus morhua respectively, have been isolated, sequenced and their encoded products overproduced as recombinant enzymes in E. coli. The proteins were characterised in terms of their kinetic and physical properties and their ability to withstand high pressures. Although the two proteins are very similar in terms of their primary structure, only 21 differences at the amino acid level exist between them, the enzyme from the deep-sea species has a significantly increased tolerance to pressure and a higher thermostability. It was possible to investigate whether the changes in the N-terminal or C-terminal regions played a greater role in barophilic adaptation by the construction of two chimeric enzymes by use of a common restriction site within the cDNAs. One of these hybrids was found to have even greater pressure stability than the recombinant enzyme from the deep-living fish species. It was possible to conclude that the major adaptive changes to pressure tolerance must be located in the N-terminal region of the protein. The types of changes that are found and their spatial location within the protein structure are discussed. An analysis of the kinetic parameters of the enzymes suggests that there is clearly a trade off between Km and kcat values, which likely reflects the necessity of the deep-sea enzyme to operate at low temperatures

A Midpoint Process Evaluation of the Los Angeles Basin Racial and Ethnic Approaches to Community Health Across the US (REACH US) Disparities Center, 2007-2009

BACKGROUND: Racial/ethnic minority groups have higher risks for disease resulting from obesity. COMMUNITY CONTEXT: The University of California, Los Angeles, and the Los Angeles County Department of Public Health partnered with community organizations to disseminate culturally targeted physical activity and nutrition-based interventions in worksites. METHODS: We conducted community dialogues with people from 59 government and nonprofit health and social service agencies to develop wellness strategies for implementation in worksites. Strategies included structured group exercise breaks and serving healthy refreshments at organizational functions. During the first 2 years, we subcontracted with 6 community-based organizations (primary partners) who disseminated these wellness strategies to 29 organizations within their own professional networks (secondary worksites) through peer modeling and social support. We analyzed data from the first 2 years of the project to evaluate our dissemination approach. OUTCOME: Primary partners had difficulty recruiting organizations in their professional network as secondary partners to adopt wellness strategies. Within their own organizations, primary partners reported significant increases in implementation in 2 of the 6 core organizational strategies for promoting physical activity and healthy eating. Twelve secondary worksites that completed organizational assessments on 2 occasions reported significant increases in implementation in 4 of the 6 core organizational strategies. INTERPRETATION: Dissemination of organizational wellness strategies by trained community organizations through their existing networks (train-the-trainer) was only marginally successful. Therefore, we discontinued this dissemination approach and focused on recruiting leaders of organizational networks

The lived experience of discrimination by white women in committed interracial relationships with black men

Abstract: This study explores the experiences of discrimination by white women in committed interracial relationships with black men within the South African context from a descriptive phenomenological perspective. Three white females in committed interracial relationships with black males were recruited and interviewed. Open-ended interviews were conducted in order to elicit rich and in-depth first-person descriptions of the participants’ lived experiences of discrimination as a result of being in committed interracial relationships. The data analysis entailed a descriptive phenomenological content analysis and description. The results of this study suggest that white women in committed interracial relationships with black men experienced discrimination in various contexts where discrimination manifests as either a negative or a positive encounter; in addition, discrimination evokes various emotional responses and is coped with in either maladaptive or adaptive ways. Finally the experience of discrimination, although personal, necessarily impacts on the interracial relationship. Discrimination experienced by white women in committed interracial relationships with black men is thus multi-layered and both an intra-personal and inter-personal phenomenon

Overcoming barriers to engaging socio-economically disadvantaged populations in CHD primary prevention: a qualitative study

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; Preventative medicine has become increasingly important in efforts to reduce the burden of chronic disease in industrialised countries. However, interventions that fail to recruit socio-economically representative samples may widen existing health inequalities. This paper explores the barriers and facilitators to engaging a socio-economically disadvantaged (SED) population in primary prevention for coronary heart disease (CHD).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; The primary prevention element of Have a Heart Paisley (HaHP) offered risk screening to all eligible individuals. The programme employed two approaches to engaging with the community: a) a social marketing campaign and b) a community development project adopting primarily face-to-face canvassing. Individuals living in areas of SED were under-recruited via the social marketing approach, but successfully recruited via face-to-face canvassing. This paper reports on focus group discussions with participants, exploring their perceptions about and experiences of both approaches.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; Various reasons were identified for low uptake of risk screening amongst individuals living in areas of high SED in response to the social marketing campaign and a number of ways in which the face-to-face canvassing approach overcame these barriers were identified. These have been categorised into four main themes: (1) processes of engagement; (2) issues of understanding; (3) design of the screening service and (4) the priority accorded to screening. The most immediate barriers to recruitment were the invitation letter, which often failed to reach its target, and the general distrust of postal correspondence. In contrast, participants were positive about the face-to-face canvassing approach. Participants expressed a lack of knowledge and understanding about CHD and their risk of developing it and felt there was a lack of clarity in the information provided in the mailing in terms of the process and value of screening. In contrast, direct face-to-face contact meant that outreach workers could explain what to expect. Participants felt that the procedure for uptake of screening was demanding and inflexible, but that the drop-in sessions employed by the community development project had a major impact on recruitment and retention.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusion:&lt;/b&gt; Socio-economically disadvantaged individuals can be hard-to-reach; engagement requires strategies tailored to the needs of the target population rather than a population-wide approach.&lt;/p&gt