Publications

This paper describes and compares 2 random-digit dialing (RDD) methods that have been used to select minority subjects for population-based research. These methods encompass the census-based method, which draws its primary sampling units from census tracts with a high proportion of minority persons, and the registry-based method, which derives its primary sampling units from a population-based cancer registry. Our study targeted Filipinos living in 10 Northern California counties, where they constitute 4% of the total population. Eligible participants (Filipina women, at least aged 20, who spoke 1 of 4 interview languages) were asked to complete a short telephone interview. Both the census and registry methods located Filipino households with comparable efficiency and with a higher yield than would be expected in a non-targeted population survey, such as the Mitofsky-Waksberg RDD method. No systematic pattern of responses was evident that would indicate that either method sampled women who were systematically less acculturated or less likely to use cancer screening tests. Although both methods offer substantial gains in efficiency, their utility is limited by generating samples that tend to over-represent high-density areas. The degree to which these methods are considered viable depends on further refinement to limit, or eliminate, their inherent selection biases without sacrificing their increased efficiency to locate minority populations.

Experimental evidence demonstrates that inflammation plays a key role in the pathogenesis of an atherosclerotic plaque. Whereas multiple, large, prospective epidemiologic studies demonstrate that C-reactive protein (CRP) and other inflammatory biomarkers predict future risk of cardiovascular disease (CVD), data on inflammation among specific ethnic groups in the United States are sparse. For example, CRP levels may vary by race/ethnicity but more data are needed to better assess this issue. Additionally, data on the relationship between white blood cell (WBC) count and CVD among African American and Hispanic participants suggest that elevated WBC is associated with increased likelihood of vascular disease. Furthermore, some research suggests that African Americans may have different fibrinolytic characteristics than white Americans. Generally, fibrinogen levels have been noted to be higher among African Americans than among white Americans. Although data regarding inflammatory biomarkers of CVD in various ethnic groups are slowly emerging, the lack of adequate representation of African Americans in clinical cohorts continues to be the limiting factor in data ascertainment.

Despite advances in cardiac arrhythmia management, atrial fibrillation remains a major cause of cardiovascular morbidity and mortality. Recent data suggests that there are periods of organization within this apparently chaotic arrhythmia. To date, analysis of the rapidly changing atrial fibrillation signal has been limited by a lack of time-frequency resolution. When used to analyze high-density atrial mappings of this arrhythmia, the continuous wavelet transform, with its time-frequency multi-resolution capability, may provide important temporal and spatial information regarding arrhythmia organization and may lead to the development of more effective therapies.

While the proximal cytoplasmic signalling events controlling the activation of NF-kappaB are understood in considerable detail, the subsequent intranuclear events that regulate the strength and duration of NF-kappaB action remain poorly defined. Recently, we have demonstrated that the RelA subunit of the NF-kappaB heterodimer is subject to reversible acetylation. The p300/CBP acetyltransferases play a major role in the in vivo acetylation of RelA principally targeting lysines 218, 221 and 310 for modification. Acetylation of these distinct lysine residues regulates different functions of NF-kappaB, including transcriptional activation, DNA binding affinity, I-kappaBalpha assembly and subcellular localization. Specifically, acetylation of lysine 221 enhances DNA binding and impairs assembly with I-kappaBalpha while acetylation of lysine 310 is required for full transcriptional activity of RelA independent of changes in DNA binding or I-kappaBalpha binding. In turn, acetylated RelA is deacetylated by histone deacetylase 3 (HDAC3). Deacetylation of lysine 221 promotes high-affinity binding of RelA to newly synthesized I-kappaBalpha proteins whose expression is activated by NF-kappaB. I-kappaBalpha binding to deacetylated RelA promotes rapid nuclear export of the NF-kappaB complex. This export is dependent on CRM1 binding to a nuclear export signal present in I-KBalpha and promotes replenishment of the cytoplasmic pool of latent NF-kappaB/I-kappaBalpha complexes thus readying the cell for response to the next NF-kappaB inducing stimulus Together, these studies highlight how reversible acetylation of RelA serves as an intranuclear molecular switch promoting both positive and negative regulatory effects on nuclear NF-kappaB action.

The fluorescence resonance energy transfer (FRET)-based HIV-1 virion fusion assay exploits the incorporation of beta-lactamase-Vpr chimeric proteins into HIV-1 virions and their subsequent delivery into the cytoplasm of target cells as a marker of fusion. This transfer can be monitored by the enzymatic cleavage of the CCF2-AM dye, a fluorescent substrate of beta-lactamase (BlaM), loaded into the target cells. BlaM cleavage of the beta-lactam ring in CCF2-AM prevents the FRET between the coumarin and fluorescein moieties of the dye. This cleavage changes the fluorescence emission spectrum of CCF2-AM from green (520 nm) to blue (447 nm), and thus permits detection of fusion by fluorescence microscopy, flow cytometry, or UV photometry. This assay is simple and rapid to perform, and exhibits high sensitivity and specificity. Importantly, it can be applied to study HIV-1 virion fusion in primary cells and can be combined with immunostaining for subset discrimination in heterogeneous target cell populations. Finally, the assay can also be adapted to study fusion mediated by the envelope proteins from other viruses through the construction of HIV-1 pseudotypes.

BACKGROUND

Serum ferritin is a frequently used marker of iron status in dialysis patients. Iron administration is to be withheld for ferritin values >800 ng/ml according to K/DOQI guidelines. We hypothesized that such non-iron-related factors as elements of the malnutrition-inflammation complex syndrome (MICS) may increase serum ferritin concentration independently of iron status.

METHODS

We studied 82 prevalent maintenance haemodialysis (MHD) patients (including 43 men), aged 55.7 +/- 15.3 years. The inflammatory and nutritional status was evaluated by serum C-reactive protein (CRP), Subjective Global Assessment (SGA) and its newer, fully quantitative versions, i.e. Dialysis Malnutrition Score (DMS) and Malnutrition-Inflammation Score (MIS).

RESULTS

All but six patients had been on maintenance doses of intravenous iron dextran (between 100 and 200 mg/month) during the 10 weeks prior to the measurements. Serum ferritin levels were increased across SGA categories: (ANOVA P-value 0.03). Both unadjusted and multivariate adjusted correlation coefficients (r) for serum ferritin and CRP vs pertinent values were statistically significant for DMS and MIS and some other measures of nutritional status and iron indices. After deleting 10 MHD patients with either iron deficiency (ferritin <200 ng/ml) or iron overload (ferritin >2000 ng/ml), in the remaining 72 MHD patients both bivariate and multivariate correlations were much stronger and statistically significant (r = -0.33 and -0.29, respectively, P < 0.01). A multivariate model showed simultaneous, significant correlations between serum ferritin and both markers of inflammation and iron status independent of each other. After dividing the 72 MHD patients into two groups of serum ferritin based on a K/DOQI recommended serum ferritin cut-off of 800 ng/ml, the MIS and logarithm of serum CRP were significantly higher in the higher ferritin group.

CONCLUSIONS

Serum ferritin values in the range of 200-2000 ng/ml may be increased due to non-iron-related factors including elements of MICS.

Complaints of health symptoms from ambient odors have become more frequent in communities with confined animal facilities, wastewater treatment plants, and biosolids recycling operations. The most frequently reported health complaints include eye, nose, and throat irritation, headache, nausea, diarrhea, hoarseness, sore throat, cough, chest tightness, nasal congestion, palpitations, shortness of breath, stress, drowsiness, and alterations in mood. Typically, these symptoms occur at the time of exposure and remit after a short period of time. However, for sensitive individuals such as asthmatic patients, exposure to odors may induce health symptoms that persist for longer periods of time as well as aggravate existing medical conditions. A workshop was held at Duke University on April 16-17, 1998 cosponsored by Duke University, the Environmental Protection Agency (EPA). and National Institute on Deafness and Other Communication Disorders (NIDCD) to assess the current state of knowledge regarding the health effects of ambient odors. This report summarizes the conclusions from the Workshop regarding the potential mechanisms responsible for health symptoms from ambient odors. Methods for validation of health symptoms, presence of odor, and efficacy of odor management techniques are described as well.