Noncanonical Role of Telomerase in Regulation of Microvascular Redox Environment With Implications for Coronary Artery Disease.

Telomerase reverse transcriptase (TERT) (catalytic subunit of telomerase) is linked to the development of coronary artery disease (CAD); however, whether the role of nuclear vs. mitchondrial actions of TERT is involved is not determined. Dominant-negative TERT splice variants contribute to decreased mitochondrial integrity and promote elevated reactive oxygen species production. We hypothesize that a decrease in mitochondrial TERT would increase mtDNA damage, promoting a pro-oxidative redox environment. The goal of this study is to define whether mitochondrial TERT is sufficient to maintain nitric oxide as the underlying mechanism of flow-mediated dilation by preserving mtDNA integrity.Immunoblots and quantitative polymerase chain reaction were used to show elevated levels of splice variants α- and ß-deletion TERT tissue from subjects with and without CAD. Genetic, pharmacological, and molecular tools were used to manipulate TERT localization. Isolated vessel preparations and fluorescence-based quantification of mtH2O2 and NO showed that reduction of TERT in the nucleus increased flow induced NO and decreased mtH2O2 levels, while prevention of mitochondrial import of TERT augmented pathological effects. Further elevated mtDNA damage was observed in tissue from subjects with CAD and initiation of mtDNA repair mechanisms was sufficient to restore NO-mediated dilation in vessels from patients with CAD. The work presented is the first evidence that catalytically active mitochondrial TERT, independent of its nuclear functions, plays a critical physiological role in preserving NO-mediated vasodilation and the balance of mitochondrial to nuclear TERT is fundamentally altered in states of human disease that are driven by increased expression of dominant negative splice variants.

Nanoparticle inhalation impairs coronary microvascular reactivity via a local reactive oxygen species-dependent mechanism.

We have shown that nanoparticle inhalation impairs endothelium-dependent vasodilation in coronary arterioles. It is unknown whether local reactive oxygen species (ROS) contribute to this effect. Rats were exposed to TiO(2) nanoparticles via inhalation to produce a pulmonary deposition of 10 microg. Coronary arterioles were isolated from the left anterior descending artery distribution, and responses to acetylcholine, arachidonic acid, and U46619 were assessed. Contributions of nitric oxide synthase and prostaglandin were assessed via competitive inhibition with N(G)-Monomethyl-L-Arginine (L-NMMA) and indomethacin. Microvascular wall ROS were quantified via dihydroethidium (DHE) fluorescence. Coronary arterioles from rats exposed to nano-TiO(2) exhibited an attenuated vasodilator response to ACh, and this coincided with a 45% increase in DHE fluorescence. Coincubation with 2,2,6,6-tetramethylpiperidine-N-oxyl and catalase ameliorated impairments in ACh-induced vasodilation from nanoparticle exposed rats. Incubation with either L-NMMA or indomethacin significantly attenuated ACh-induced vasodilation in sham-control rats, but had no effect in rats exposed to nano-TiO(2). Arachidonic acid induced vasoconstriction in coronary arterioles from rats exposed to nano-TiO(2), but dilated arterioles from sham-control rats. These results suggest that nanoparticle exposure significantly impairs endothelium-dependent vasoreactivity in coronary arterioles, and this may be due in large part to increases in microvascular ROS. Furthermore, altered prostanoid formation may also contribute to this dysfunction. Such disturbances in coronary microvascular function may contribute to the cardiac events associated with exposure to particles in this size range.

Nanoparticle inhalation impairs endothelium-dependent vasodilation in subepicardial arterioles.

Exposure to fine particulate matter (PM, mean aerodynamic diameter

Religiosity and the expansion of caregiver stress.

We present a stress process framework as a model for understanding how religiosity may influence the expansion of stress. Survey data from informal caregivers to a spouse with Alzheimer's disease or a related dementia (n = 200) were analyzed to observe the relationships among three variables: (1) care-related stress, (2) religiosity, and (3) depression. This sample, which has a mean age of 73 years, demonstrates high rates of self-described religiosity, church attendance and frequency of prayer. Using these criteria, women and racial/ethnic minority caregivers are the most religious. In a series of multivariate analyses, we found strong evidence to suggest that there is an expansion of care-related stressors leading to depression in this sample. Religiosity, as measured here, appears to be largely unrelated to stress and stress expansion. We found no evidence to suggest that it moderates stress expansion. However, these data do suggest that one stressor--feelings of role overload--is correlated with greater levels of self-perceived religiosity, which among caregivers who have health problems of their own is associated with greater depressive symptomatology. Thus, for a sub-sample of these caregivers, we find weak evidence of a mediation effect wherein one subjective, non-organizational dimension of religiosity is a conduit of the harmful effects of stress (rather than a suppressor). Results and data limitations are discussed in relation to better assessing the role of religiosity and spirituality in the experience of the stress process.

Stress buffering effects of family support in AIDS caregiving.

This study examines the effects of family support on AIDS caregiver stress over time, comparing HIV-positive and HIV-negative gay-identified men who care for a friend or partner living with HIV (PLWH). Support from the care-recipient's family of origin is assessed, and the stress buffering effects of this type of support are explored longitudinally within a stress proliferation framework for 276 men (114 were HIV-positive, 162 were HIV-negative). Among HIV-positive caregivers, emotional distress is associated with high caregiving stress and low PLWH family support. Emotional distress among HIV-negative caregivers is also associated with caregiving stress, but is not significantly influenced by support from the PLWH's family. For both groups, increasing emotional distress over a seven-month period is a function of increasing caregiver stress, but not PLWH family support. The effects of financial worry and role overload on caregiver emotional distress are conditional upon PLWH family support at Time 1 among HIV-positive caregivers, such that support buffers the distressing impact of financial worry, but may exacerbate the distressing impact of role overload. In addition to characterizing processes of stress proliferation and social support, this research also illustrates how families of choice and families of origin simultaneously shape the experience of the caregiving role and its influence on the wellbeing of gay men.

State long-term care screening and assessment programs.

Long-term care screening and assessment programs were designed by states to control long-term care costs and to prevent unnecessary institutionalization of Medicaid participants. This study reports data collected by telephone survey of state officials in all 50 states and Washington, D.C. on state variation in LTC screening and assessment programs. The majority of the state screening and assessment programs cover an array of LTC services but this has resulted in multiple separate screening programs for different long-term care services and eligibility groups. Only three states coordinated screening and assessment across long-term care programs by operating a single state administrative agency, using uniform need criteria and standard tools, and having automated databases (Arizona, Colorado, and Maine). The design and implementation of multiple and separate screening and assessment programs in most states may create potential barriers to client access, information about services and choice of services.

State Medicaid programs offering personal care services.

Two Medicaid programs offer personal care services: (1) the Title XIX Personal Care Services (PCS) optional State plan benefit; and (2) the 1915(c) home and community-based services (HCBS) waivers. By 1998-1999, 26 States offered the PCS optional State plan benefit; 45 offered personal care services via a waiver(s). Nationwide, the former program was larger. The latter was the more popular administrative mechanism, possibly because it more reliably controls growth. States vary dramatically in terms of Medicaid personal care. Medicaid personal care participants per 1,000 State population ranged from 7.33 to 0.04. Per capita expenditures ranged from $91.21 to $0.02.

Medicaid 1915(c) home and community-based services waivers across the states.

This article provides State-level data on the Medicaid 1915(c) home and community-based services (HCBS) waivers program. Medicaid 1915(c) waiver participants were 32 percent of the Medicaid participants in institutional care in 1997. These data document wide interstate variation in organizational oversight and program policies for the waivers. Many structural barriers to HCBS waiver growth existed. Case management services, in some form, were normative for most HCBS waiver participants, but formal mechanisms to assess client satisfaction and service quality were less common. Substantial new growth in this program may require fundamental changes in HCBS waiver policies.

A nuclear encoded and mitochondrial imported dicistronic tRNA precursor in Trypanosoma brucei.

The mitochondrial tRNAs of Trypanosoma brucei are nuclear encoded and imported into the mitochondrion. A heterogeneous population of RNAs having characteristics of precursor tRNAs have previously been identified within the mitochondrion of T. brucei, suggesting that import occurs via a precursor molecule. In order to identify nuclear genes encoding tRNAs targeted to the mitochondrion, individual mitochondrial tRNAs were separated using two-dimensional gel electrophoresis and enzymatically sequenced. A 1.1-kilobase pair genomic DNA fragment was cloned containing three tRNA genes, tRNA(1)(Ser), tRNA(Leu), and tRNA(2)(Ser). Dicistronic precursors containing the tRNA(1)(Ser) and tRNA(Leu) transcripts with a 59-nucleotide intergenic sequence were identified by reverse transcriptase and polymerase chain reactions and the 5' end of the precursors determined. The dicistronic precursor tRNA is present both in the cytosol and the mitochondrion supporting a model for tRNA import involving precursor tRNA transcripts.

The integration of informal care, case management and community-based services for persons with HIV/AIDS.

This research examines the integration of informal and formal care for persons with HIV/AIDS. Data come from a panel survey of informal HIV/AIDS caregivers (N = 642) and are analyzed using a modified version of the Behavioral Model that allows for inclusion of predisposing, enabling and need characteristics of persons with HIV/AIDS and their caregivers. The outcome component of our model emphasizes the role of case management as an intermediary service designed to facilitate linkage to other services. Results indicate: substantial use of case management and other services among persons receiving informal care; characteristics of care recipients, caregivers and dyads directly influence case management and service use; case management positively influences service use at baseline and change in service use over time; and the association between case management and service use generates indirect influences on service use related to characteristics of care recipients, caregivers and dyads. These results highlight the importance of case management as a mechanism for integrating informal and formal care and demonstrate that service utilization is influenced by the social context of illness.

AIDS caregiving and health among midlife and older women.

This study reports on analyses of survey data from 121 midlife and older women engaged in AIDS caregiving in Los Angeles and San Francisco. These data revealed that these women provided substantial support to persons living with HIV or AIDS (PWAs) despite other role commitments associated with family and work. Although the characteristics of these women differed according to their relationship to the PWA (mother, wife, sister, or friend), they tended to be similar with regard to both the amount of care provided and its impact on their health. The results indicated that the severity of the PWA's illness and the duration of caregiving were more consequential to health than were the hands-on tasks of caregiving.

The forms and mechanisms of stress proliferation: the case of AIDS caregivers.

Processes of stress proliferation are explored in a sample of informal caregivers to people with AIDS. Proliferation refers to the tendency for stressors to beget stressors. Two forms of proliferation are explored, each based on the distinction between primary and secondary stressors. Among AIDS caregivers, primary stressors are the hardships rooted in the caregiving role. Secondary stressors result from primary stressors, but arise in roles and activities outside of caregiving. One form of proliferation is the expansion of primary stressors, reflected in an increase in role overload and a growing sense of being a captive of the caregiver role. Expansion is largely driven by the course of AIDS and the elevation of demands it places on the caregiver. The second form of proliferation is the surfacing of secondary stressors in social and leisure life and in the occupational realm. This form arises from the strains imposed by the emerging caregiver role on the other roles and activities of the caregiver. It is proposed that the systematic assessment of proliferated stressors can help illuminate the dynamic connections between stress and health.

The physical costs of AIDS caregiving.

Informal care has become an increasingly important element in the delivery of health and social services to people living with HIV disease or AIDS (PWAs), yet the provision of such care does not come without costs to the caregiver. Instead, caregiving imposes burdens that may compromise caregiver health. Common ailments among AIDS caregivers were examined with two waves of data from a diverse sample of informal care providers in Los Angeles and San Francisco (N = 642). Symptoms of poor physical health are markedly present among AIDS caregivers and are significantly associated with care-related demands and stressors. This stress and health relationship varies significantly between caregivers who are HIV seropositive and those who are seronegative. Care-related effects are more direct among seronegative caregivers who are perhaps less overwhelmed with the maintenance of their own health. For all caregivers studied, level of depression and prior physical health are strong correlates of these physical ailments. Implications of these results are discussed.

Adoption of HIV-related services among urban US hospitals: 1988 and 1991.

Recent reports document that US hospitals vary considerably, notably by ownership, in the number of acquired immunodeficiency syndrome (AIDS) patients they treat. Still, little is known about other types of hospital response to human immunodeficiency virus (HIV) and AIDS and the relative strength of ownership as a determining factor. With annual survey data from the American Hospital Association the authors examine the formal adoption of HIV-related services among urban US hospitals at the turn of the decade. Descriptive analyses of 2 years of data (1988 and 1991) are presented. A multivariate logistic regression analysis, conducted on the 1991 data, tests for unique ownership effects on the likelihood that hospitals are heavy investors in HIV-related care. Patterns of service adoption for 1991 strongly resemble those for 1988. Nearly three fourths of urban US hospitals offer general inpatient AIDS care, and over half provide HIV testing. Few urban hospitals offer outpatient services; even fewer operate AIDS units. A substantial minority report no formal adoption of HIV-related services. For-profit hospitals stand out as least likely to formally adopt these HIV-related services. Those adopting a comprehensive set of HIV-related services typically are public or secular, not-for-profit in ownership, large, affiliated with a medical school, and high volume users of Medicaid funding. The logistic regression analysis suggests that public ownership is a key determinant of greater service investment, even after controlling for other explanatory factors. This study appears to mirror a familiar pattern of hospital response to undercompensated care in the United States.

Support service use by persons with AIDS and their caregivers.

The purpose of this study was to identify factors related to the use and non-use of emotional and practical support services by persons with AIDS (PWAs) and their informal caregivers. Unmet need for PWA support services and perceived barriers to the use of these types of services were also identified. Structured interviews were conducted with 472 self-selected informal AIDS caregivers in greater Los Angeles and the San Francisco Bay area. Data from a cross-sectional survey interview were analysed using logistic regression models fit for three categories of service use. Use of support services was substantial in this sample. Case management, caregiver HIV status, education, co-residence, and type of interpersonal relationship were important predictors of service use. Unmet need for PWA services was also substantial. The PWA's unwillingness to use services and lack of access were identified as key barriers to service use. Even in the presence of an informal caregiver, PWAs require considerable supplemental assistance from institutional sources. The presence of informal assistance to PWAs does not eliminate the need for institutional support. Moreover, caregivers themselves demonstrate considerable need for support.

Examining HIV-related knowledge among adults in the U.S.

Supplemental AIDS data from the 1987 National Health Interview Survey indicate that adults in the U.S. know the most frequent modes of HIV transmission, but lack a more comprehensive understanding of HIV and AIDS. Elements from a diffusion model were isolated to create a path-analytic framework for examining the effects of population or recipient characteristics and information sources or communication channels on HIV-related knowledge with these data. This multivariate analysis suggests that persons of lower socioeconomic status, older adults, those from racial/ethnic minority groups, those living outside of metropolitan areas, men, and those citing mass media (television or newspapers) as their primary source of information about HIV and AIDS have slightly lower levels of HIV-related knowledge. Decomposition of the effects in the path analysis suggests that use of information sources or channels, as measured by survey data, accounts for little of the observed variation in HIV-related knowledge. The implications of these results for future research and HIV-related education are discussed.

Generation of a restriction fragment length polymorphism linkage map for Toxoplasma gondii.

We have constructed a genetic linkage map for the parasitic protozoan, Toxoplasma gondii, using randomly selected low copy number DNA markers that define restriction fragment length polymorphisms (RFLPs). The inheritance patterns of 64 RFLP markers and two phenotypic markers were analyzed among 19 recombinant haploid progeny selected from two parallel genetic crosses between PLK and CEP strains. In these first successful interstrain crosses, these RFLP markers segregated into 11 distinct genetic linkage groups that showed close correlation with physical linkage groups previously defined by molecular karyotype. Separate linkage maps, constructed for each of the 11 chromosomes, indicated recombination frequencies range from approximately 100 to 300 kb per centimorgan. Preliminary linkage assignments were made for the loci regulating sinefungin resistance (snf-1) on chromosome IX and adenine arabinoside (ara-1) on chromosome V by linkage to RFLP markers. Despite random segregation of separate chromosomes, the majority of chromosomes failed to demonstrate internal recombination events and in 3/19 recombinant progeny no intramolecular recombination events were detected. The relatively low rate of intrachromosomal recombination predicts that tight linkage for unknown genes can be established with a relatively small set of markers. This genetic linkage map should prove useful in mapping genes that regulate drug resistance and other biological phenotypes in this important opportunistic pathogen.

Identification of nuclear encoded precursor tRNAs within the mitochondrion of Trypanosoma brucei.

RNAs that function in mitochondria are typically encoded by the mitochondrial DNA. However, the mitochondrial tRNAs of Trypanosoma brucei are encoded by the nuclear DNA and therefore must be imported into the mitochondrion. It is becoming evident that RNA import into mitochondria is phylogenetically widespread and is essential for cellular processes, but virtually nothing is known about the mechanism of RNA import. We have identified and characterized mitochondrial precursor tRNAs in T. brucei. The identification of mitochondrially located precursor tRNAs clearly indicates that mitochondrial tRNAs are imported as precursors. The mitochondrial precursor tRNAs hybridize to cloned nuclear tRNA genes, label with [alpha-32P]CTP using yeast tRNA nucleotidyltransferase and in isolated mitochondria via an endogenous nucleotidyltransferase-like activity, and are processed to mature tRNAs by Escherichia coli and yeast mitochondrial RNase P. We show that T. brucei mitochondrial extract contains an RNase P activity capable of processing a prokaryotic tRNA precursor as well as the T. brucei tRNA precursors. Precursors for tRNA(Asn) and tRNA(Leu) were detected on Northern blots of mitochondrial RNA, and the 5' ends of these RNAs were characterized by primer extension analysis. The structure of the precursor tRNAs and the significance of nuclear encoded precursor tRNAs within the mitochondrion are discussed.

Incidence of Clostridium botulinum in crabmeat from the blue crab.

The incidence of Clostridium botulinum in fresh crabmeat of blue crab was six out of 986 samples; in pasteurized crabmeat one sample out of 1,000 contained the organism.