Absence of Mycobacterium bovis infection in dogs and cats residing on infected cattle farms: Michigan, 2002.

A cross-sectional field study was performed to evaluate infection in dogs and cats living on farms with Mycobacterium bovis-infected cattle. The purpose was to determine pet infection status and assess their risk to farm families and/or tuberculosis-free livestock. Data and specimens were collected from 18 cats and five dogs from nine participating farms. ELISA testing for M. bovis and M. avium was conducted. Fifty-one biological samples were cultured; all were negative for M. bovis, although other Mycobacterium species were recovered. No radiographic, serological or skin test evidence of mycobacterial infection was found. These negative results may be due to the low level of M. bovis infection in the cattle and the limited duration of exposure of pets to infected cattle residing on the same farm. No evidence was found to indicate that pets residing on M. bovis-infected Michigan cattle farms pose a risk to humans or M. bovis-free livestock; however, precautionary advice for farm owners was provided.

Experimental inoculation of wild turkeys (Meleagris gallopavo) with Mycobacterium bovis.

Although avian species are known to be susceptible to infection with Mycobacterium spp. organisms, much remains unknown about the susceptibility of birds to infection with M. bovis. The objective of this current study was to determine if wild turkeys (Meleagris gallopavo) can be infected with M. bovis when inoculated by the oral or intratracheal route. Six turkeys were orally inoculated and another six were inoculated via the trachea with a high dose of M. bovis, 1 x 10(5) CFU/ml. Six turkeys were sham-inoculated controls. Two turkeys from each treatment group were sacrificed on days 30, 60, and 90 postinoculation. There were no gross or microscopic lesions consistent with mycobacteriosis in the 23 inoculated turkeys over the 90-day duration of this study. Fecal cultures were also consistently negative for M. bovis when sampled before inoculation and on days 1, 30, and 60 postinoculation. Two intratracheally inoculated turkeys were positive for M. bovis in visceral tissues at 30 days postinoculation. However, this finding was only indicative of passive persistence of mycobacteria in the tissues and not of infection, as there were no attendant lesions or clinical compromise to support infection. Thus, it can be concluded that young wild turkeys are resistant to infection with M. bovis and, therefore, pose minimal threat as reservoir or spillover hosts for this organism.

Resistance of Mallard ducks (Anas platyrhynchos) to experimental inoculation with Mycobacterium bovis.

The purpose of this study was to investigate whether mallard ducks (Anas platyrhynchos) are susceptible to infection with Mycobacterium bovis by either oral or intratracheal inoculation and to assess their potential role in the spread of bovine tuberculosis. Six ducks were orally inoculated with 1.0 x 10(5) colony-forming units of M. bovis, six ducks were intratracheally inoculated with the same dose, and six ducks served as sham-inoculated controls. The study length was 90 days postinoculation, with samples of two birds from each group necropsied at 30-day intervals. Both fecal and tissue samples were collected for mycobacterial culture. None of the inoculated ducks shed M. bovis in their feces at any culture point (days 1, 30, and 60) during the study. No evidence of illness or weight loss was present during the course of the study, and only one duck had M. bovis isolated from any tissue, although there were no associated microscopic lesions. Mallard ducks were highly resistant to infection with M. bovis following high-dose inoculation and did not shed the organism in their feces. This study was conducted using high-dose inoculation; therefore, it appears that ducks are unlikely to play any significant role in the transmission of M. bovis between infected and uninfected mammalian hosts.

Experimental inoculation of pigeons (Columba livia) with Mycobacterium bovis.

The purpose of this pilot study was to determine if pigeons (Columba livia) are susceptible to infection with Mycobacterium bovis by either oral or intratracheal inoculation and to assess their possible role in the lateral transmission of bovine tuberculosis. Six pigeons were orally inoculated with 1.3 x 10(5) colony-forming units of M. bovis, six pigeons were intratracheally inoculated with the same dose, and six pigeons served as noninoculated controls. The study continued for 90 days postinoculation (PI), with groups of birds necropsied at 30-day intervals, and fecal samples and tissues were collected for mycobacterial culture. Two pigeons, one intratracheally inoculated and one orally inoculated, shed M. bovis in their feces at 1 day PI, and one intratracheally inoculated bird shed M. bovis in its feces 60 days PI. Whereas no illness or weight loss was present during the course of the study, 2 of 12 inoculated birds exhibited microscopic lesions of mycobacteriosis, and the organism was isolated from tissues of three inoculated birds. Pigeons are susceptible to infection with M. bovis after high dose inoculation and can shed the organism in their feces for up to 60 days PI; intratracheally inoculated birds appear more likely to become active fecal shedders of M. bovis. Although these were high dose inoculations under experimental conditions, pigeons may potentially play a role in the lateral transmission of bovine tuberculosis between infected and uninfected mammalian hosts.

Experimental inoculation of European starlings (Sturnus vulgaris) and American crows (Corvus brachyrhynchos) with Mycobacterium bovis.

The purpose of this series of pilot studies was to determine whether the passerine species studied are susceptible to infection with Mycobacterium bovis. Separate experiments were conducted on wild-caught starlings (Sturnus vulgaris) and American crows (Corvus brachyrhynchos). In each experiment, four birds were challenged intraperitoneally and four were challenged orally with microorganisms. Challenge dose was 1 x 10(5) colony-forming units of M. bovis cultured from a white-tailed deer (Odocoileus virginianus) case in Michigan. Birds were euthanatized at 1 and 2 mo postinoculation. Histologic lesions suggestive of mycobacteriosis, without the presence of acid-fast bacilli, were noted in all experimental groups. Mycobacterial cultures performed on pooled tissue samples were positive for M. bovis in only some of the intraperitoneal inoculates of each species.

Comparison of postmortem techniques for the detection of Mycobacterium bovis in white-tailed deer (Odocoileus virginianus).

A retrospective study of various diagnostic postmortem techniques used in a 4-year surveillance program for detection of Mycobacterium bovis infection in wild white-tailed deer (Odocoileus virginianus) was conducted. The tests evaluated were routine histopathology, acid-fast staining, detection of acid-fast bacilli in culture, and an M. tuberculosis group-specific genetic probe applied to pure cultures. Each of these techniques were compared with a reference or "gold standard" of mycobacterial culture and identification. Histopathology, the most rapid form of testing for M. bovis infection in white-tailed deer samples, had a sensitivity of 98% and a specificity of 87%, resulting in a positive predictive value of 94%. The detection of acid-fast bacilli by staining was less sensitive than histopathology (90%), but its higher specificity (97%) resulted in a positive predictive value of 99%. The detection of acid-fast bacilli on culture was both highly specific (93%) and sensitive (100%). The group-specific genetic probe had the highest sensitivity and specificity and produced results in complete agreement with those of mycobacterial culture, suggesting that this technique could be used as the new "gold standard" for this particular wildlife tuberculosis surveillance program.

Rural acquired immunodeficiency syndrome in low and high prevalence areas.

BACKGROUND: Too little is understood about the spread of the acquired immunodeficiency syndrome (AIDS) in rural America. This study focuses on changes over 5 years in two low prevalence and two high prevalence human immunodeficiency virus (HIV) rural service areas. METHODS: An initial study conducted in 1993 provided a base line for the study. Each site was revisited in the summer of 1998. Data were analyzed by degree of rurality of the site, prevalence levels, and risk categories. RESULTS: Changes in the number of AIDS cases ranged from slow steady growth to increases of an epidemic magnitude. Some settings were characterized primarily by white homosexual men, and others had a more diverse population living in poverty. CONCLUSIONS: Populations receiving priority for national AIDS funding should be expanded to include rural America as a target group, and funding should provide the latitude for communities to match their local needs.

Economic impact of hospital closure on small rural counties, 1984 to 1988: demonstration of a comparative analysis approach.

Hospital closure in a rural community may affect the locale's economic prospects as well as the health of its residents. Studies of economic effects have primarily relied on modeling techniques rather than observation of actual change. This study demonstrates the use of a comparative analysis approach for estimating the economic effects of hospital closure on small rural counties. The experiences of 103 small rural counties at which a hospital closed between 1984 and 1988 was compared with a matched group of counties at which no closure took place. "Comparable" counties were selected based on seven scales measuring the similarity between a closure county and potential comparisons. Three scales examined population and economic characteristics in the year before closure; two scales measured change throughout a three-year period preceding closure; and two scales measured change throughout a five-year period preceding closure. Closure effects were measured through a multivariate analysis of the post-closure economic history of closure and comparison counties. The key assumption is that similar counties should have similar experiences over time. If an event occurs within some of these counties but not others, this event should have visible effects. Comparative analysis suggested that earned income in closure counties (excluding farming and mining income) was lower than in comparison counties subsequent to closure and that labor force growth was similarly affected. A comparative analysis approach produces results that parallel those obtained from economic modeling and should be considered for further research.

A typological approach to the study of rural HIV service delivery networks.

Despite the rapid growth of AIDS cases in nonmetropolitan areas, little is known about the characteristics and needs of HIV-positive rural residents or how rural areas are responding to the epidemic. This paper proposes a typology for distinguishing among rural environments and examining variations in HIV service networks. The typology identifies three dimensions that have a major effect on the development of rural HIV service networks: degree of rurality, the prevalence of AIDS, and the epidemiological and demographic characteristics of the infected populations. Data from four case studies are used to illustrate how variations in rural environments can affect the organization and delivery of HIV/AIDS care. The typology contributes to public policy discussions by identifying key attributes of rural environments that influence program planning and implementation and the transferability of service delivery models.

Vitamin D3 reduces the apoptotic effect of IFN-gamma but does not facilitate HLA class II inducibility in RB-defective cells.

The retinoblastoma protein (RB) regulates the cell cycle by binding and inactivating the E2F transcription factors, which prevents transcription of genes required for DNA synthesis. RB has been shown to inhibit IFN-gamma-mediated apoptosis, possibly by regulating premature entry into S phase. RB is also required for high level IFN-gamma induction of HLA class II genes, which encode antigen presenting molecules, but not for other IFN-gamma inducible genes as demonstrated in previous reports describing the analysis of RB-transformants of the RB-defective cell lines, MDA-468-S4 (S4) and H2009. The IFN-gamma response of the HLA class II genes takes much longer than does the response of the other IFN-gamma inducible genes, raising the question of whether RB facilitates HLA class II inducibility by maintaining cell viability over the long time course required for HLA class II induction. Thus, we sought to learn whether IFN-gamma induced apoptosis in an RB-defective cell line could be prevented independently of RB and whether doing so would facilitate HLA class II inducibility in the RB-defective line. Our results indicated that cotreating the RB-defective S4 cells with IFN-gamma and Vitamin D3 decreased the number of cells containing subdiploid DNA compared to cells treated with IFN-gamma alone, suggesting that Vitamin D3 reduced IFN-gamma-mediated apoptosis. S4 cells cotreated with Vitamin D3 and IFN-gamma also had decreased cell detachment, further indicating that Vitamin D3 decreased IFN-gamma induced apoptosis. However, Vitamin D3 cotreatment resulted in no detectable increase in HLA-DR, the most prominent HLA class II molecule, indicating that the effect of RB on HLA class II induction is not exclusively due to its ability to inhibit IFN-gamma induced apoptosis.

Retinoblastoma protein inhibits IFN-gamma induced apoptosis.

Regulation of apoptosis (programmed cell death) is critical for maintaining tissue homeostasis. Recent studies indicate a tight coupling between cellular proliferation and apoptosis as cell cycle regulators such as Cyclin D, E1A and E7 appear to influence both events. Each of these modulators is able to bind to and inhibit the function of the retinoblastoma tumor suppressor protein (RB). RB functions, in part, by binding to and inactivating E2F transcription factors, preventing expression of E2F-activated genes associated with G1/S cell-cycle progression. Loss of functional RB deregulates E2F activity and, depending on cell type and environmental factors, promotes tumorigenesis or apoptotic death. To determine the effect of RB on IFN-gamma induced apoptosis, we treated RB-defective carcinoma cell lines and their respective RB-constituted sister clones with IFN-gamma and examined the cells for alterations characteristic of apoptosis. We observed that RB-defective cells, but not the RB-reconstituted clones, decreased in size following IFN-gamma treatment. IFN-gamma treatment caused increased cell detachment in the RB-defective lines but did not affect adherence of the RB-reconstituted clones. Assays for DNA fragmentation revealed lower molecular weight DNA and the apoptosis-associated oligo-nucleosomal ladder following IFN-gamma treatment of the RB-defective cells while higher molecular weight DNA was present in the IFN-gamma treated, RB-reconstituted lines. IFN gamma-induced apoptosis in RB-defective cells was enhanced by serum stimulation, which is also characteristic of p53-dependent E2F-1-mediated apoptosis. However, IFN-gamma induced apoptosis in RB-defective lines does not require wild-type p53 suggesting that, upon IFN-gamma induction, deregulated E2F-mediated apoptosis can also proceed via p53-independent pathways.

Assuring access to rural health services: the case for revitalizing small rural hospitals.

Many small rural hospitals play a critical role in assuring access to basic health care services, and it is in the public interest for these hospitals to receive the necessary support to revitalize their capabilities, especially with the growing challenges of rural acquired immune deficiency syndrome (AIDS), rural drug problems, an aging population, and a growing number of uninsured and underinsured rural residents.

Patient and physician characteristics affecting the choice of home based hospice, acute care inpatient hospice facility, or hospitals as last site of care for patients with cancer of the lung.

In this exploratory study we found that in 1986, in Clark County, Nevada, home based hospice services were utilized at a very limited level for lung cancer patients. A nontraditional acute care hospice facility, however, was heavily utilized; but only slightly less so than community hospitals. Using death certificate and state cancer registry data, we explored several factors affecting these choices of sites of treatment of the last episode of illness. Among them were sociodemographic characteristics of patients, physicians' specialty, and volume of patients with terminal cancer of the lung. The findings and hypotheses lend support to further studies of the most cost effective last site of care for terminal lung cancer. The need for an ongoing examination of the impact of public policy on the definition of hospice and careful consideration of nontraditional models is indicated.

The emerging epidemiology of rural AIDS.

The incidence of AIDS in rural areas is increasing rapidly. However, historically it has been overshadowed by AIDS in the epicenters. From 1991-1992 the increased percentage of cases was higher in nonmetropolitan areas than in any other areas of residence. The rate per 100,000 also increased at almost the same rate in rural areas as in the largest metropolitan areas, defined by the Centers for Disease Control (CDC) as having a population of more than 500,000, and in other metropolitan areas of 50,000 to 500,000 population, as designated by CDC. To date, the epidemiology of AIDS in rural areas has not been defined. This information is necessary to developing effective policies and programs. The research presented here reviews the literature on AIDS in specific areas and populations at risk as a basis for generating hypotheses for further study. The first wave of the epidemic, primarily affecting homosexual or bisexual men, is strongly evident in many rural locations. The second wave of the epidemic is strongly evident in the South and can be seen among high-risk groups such as black women, adolescents, migrant and seasonal farm workers, people who abuse alcohol, intravenous drug users, and users of crack cocaine, including those who trade sex for drugs. Poverty is a common characteristic of the second-wave population. Proximity to interstate highways as well as metropolitan areas may also be associated. A national study of the epidemiology of AIDS in rural America is imperative.

HIV infection in traditional rural communities.

The challenge to rural nurses to deliver knowledgeable and skilled nursing and health care to individuals with HIV infection and AIDS is indeed tremendous. Isolation of rural communities and health care facilities coupled with limited resources, financial concerns, conservative values of many traditional rural communities, and the tendency to exclude those who do not conform to community norms make it difficult to integrate the individual with HIV disease into the rural health care delivery system fully. Issues of particular concern to the rural nurse include maintenance of client confidentiality, obtaining and maintaining current knowledge and skills necessary to the provision of quality HIV nursing care, management of complex client health care problems, and provision of appropriate support services. Rural nurses must be innovative and creative in developing mechanisms to deal with these concerns. In addition, because rural nurses are well respected by the community and viewed as possessing a great deal of expertise in the delivery of health care, they are well positioned to provide leadership to the community in developing educational and care strategies to more effectively provide HIV care. Indeed, the delivery of high-quality HIV care in rural areas across the United States will likely depend on the expertise and leadership provided by rural nurses.

HIV issues for rural hospitals in U.S. frontier areas.

A Survey of 108 hospital administrators in the eight states of the Mountain Census Region was conducted to identify frontier rural hospitals' experiences (fewer than 50 beds) in the provision of care and services to patients with HIV infection; to assess the availability of HIV care and services in these small, remote rural hospitals; and to assess the status of education and policy development related to HIV infection. Of the 62 hospitals that responded, 16 (26%) had provided care and services to HIV-infected patients. Acute inpatient and emergency room care were the services most commonly utilized. An additional 11 hospitals reported the presence of HIV-positive individuals in their medical service areas. Thus, nearly 44 percent of the hospitals were aware of the importance of addressing HIV infection as a local concern. Employees in the hospitals that had experienced caring for HIV-positive persons expressed more concern about acquiring HIV infection than those in hospitals that had not. Four nursing assistants, two registered nurses, and one dietary worker had refused to provide care. HIV education consisted primarily of video programs, presentations by in-house staff, and sending employees away to workshops. Despite this HIV education, most staff remain fearful of caring for HIV infected patients. Major concerns expressed by the hospital administrators were related to enforcing universal precautions, confidentiality, staff response, community acceptance, and cost of care. Only 30 hospitals (48%) had AIDS policies in effect, and these focused primarily on infection control and universal precautions.(ABSTRACT TRUNCATED AT 250 WORDS)

A strategy for identifying novel, mechanistically unique inhibitors of topoisomerase I.

While the design of molecules that inhibit or antagonize the functions of specific macromolecules is now well precedented, in many cases the structural information requisite to the design process is lacking. The tools of molecular biology can now furnish the target macromolecules for use in mechanism-based exploration; highly defined assays can be devised based upon the known biochemistry of these macromolecules to permit the discovery of novel inhibitors or antagonists present in chemical collections. Presently, we describe a set of assays directed toward the discovery of novel inhibitors of eukaryotic topoisomerase I, an enzyme critical to maintenance of chromosomal DNA topology and therefore essential for normal replication and transcription. The identification of chebulagic acid as an extraordinarily potent and mechanically novel inhibitor of topoisomerase I illustrates the potential of this approach.

9-Octadecynoic acid: a novel DNA binding agent.

A novel bioassay was developed to permit the identification of cytotoxic natural principles that bind to DNA. A hexane extract of Schoepfia californica cytotoxic to cultured KB cells displayed much less cytotoxic potential when the culture medium contained exogenously added calf thymus DNA. Fractionation of the extract afforded a purified principle shown to be 9-octadecynoic acid, an 18-carbon, unbranched acetylenic fatty acid. 9-Octadecynoic acid had an apparent DNA dissociation constant of 1.8 mM; it inhibited topoisomerase I mediated DNA filter binding but did not inhibit the DNA topoisomerase I mediated relaxation of a supercoiled plasmid DNA. The fatty acid was weakly inhibitory to DNA polymerase alpha. 9-Octadecynoic acid possesses none of the structural characteristics of known DNA binding molecules and may bind to DNA by some novel mechanism.