Reversible denaturation of oligomeric human chaperonin 10: denatured state depends on chemical denaturant.

Chaperonins cpn60/cpn10 (GroEL/GroES in Escherichia coli) assist folding of nonnative polypeptides. Folding of the chaperonins themselves is distinct in that it entails assembly of a sevenfold symmetrical structure. We have characterized denaturation and renaturation of the recombinant human chaperonin 10 (cpn10), which forms a heptamer. Denaturation induced by chemical denaturants urea and guanidine hydrochloride (GuHCl) as well as by heat was monitored by tyrosine fluorescence, far-ultraviolet circular dichroism, and cross-linking; all denaturation reactions were reversible. GuHCl-induced denaturation was found to be cpn10 concentration dependent, in accord with a native heptamer to denatured monomer transition. In contrast, urea-induced denaturation was not cpn10 concentration dependent, suggesting that under these conditions cpn10 heptamers denature without dissociation. There were no indications of equilibrium intermediates, such as folded monomers, in either denaturant. The different cpn10 denatured states observed in high [GuHCl] and high [urea] were supported by cross-linking experiments. Thermal denaturation revealed that monomer and heptamer reactions display the same enthalpy change (per monomer), whereas the entropy-increase is significantly larger for the heptamer. A thermodynamic cycle for oligomeric cpn10, combining chemical denaturation with the dissociation constant in absence of denaturant, shows that dissociated monomers are only marginally stable (3 kJ/mol). The thermodynamics for co-chaperonin stability appears conserved; therefore, instability of the monomer could be necessary to specify the native heptameric structure.

Assessing cultural sensitivity in printed cancer materials.

OBJECTIVES: Printed cancer education materials (PCEMs) (pamphlets and fact sheets) are used to educate individuals about cancer prevention and awareness. Culture is an important variable affecting the retention and use of information in printed materials to African Americans that has not been fully addressed in the literature. MATERIALS AND METHODS: The major goal of the Cancer Prevention Materials for African Americans project, funded by the Texas Cancer Council, was to assess cultural sensitivity of currently disseminated PCEMs targeting African Americans. The project consisted of conducting focus groups, forming an advisory committee, and developing and using the Printed Cancer Education Materials for African Americans Cultural Sensitivity Assessment Tool. RESULTS: Cultural sensitivity of PCEMs was assessed in terms of format, visual message, and written message. The majority of the PCEMs (56.2%) were culturally insensitive, with the visual message being the weakest component of all the materials. CONCLUSION: Future PCEMs targeting African Americans should include culturally sensitive visual messages to be more effective in delivering the cancer prevention message. The use of the assessment tool can assist cancer control specialists in developing culturally sensitive materials.

Cost considerations as potential barriers to cancer treatment.

PURPOSE: An analytical cross-sectional survey was conducted to determine the prevalence of barriers to cancer treatment in Texas as perceived by diagnosed cancer patients. Results reported here address the role of insurance coverage, indirect costs (transportation, lodging, and work days lost), and direct costs of care as barriers to treatment for white, black, and Hispanic cancer patients. Specific objectives of the analyses undertaken here are to examine 1) racial/ethnic differences in insurance coverage; 2) barriers relating to insurance coverage experienced by cancer patients; and 3) role of treatment-related costs as barriers to cancer treatment. DESCRIPTION OF STUDY: A mail questionnaire was developed to assess the perceived barriers to cancer treatment in Texas for adult cancer patients, 17 years and older, who had been diagnosed with breast, colon, cervical, prostate, or lymphoma during the period of 1989 to 1993. The sampling frame for this study was obtained from a network of cancer treatment facilities throughout the state of Texas within the University of Texas M.D. Anderson Cancer Center Texas Community Oncology Network. A total of 593 cancer patients returned their surveys, yielding a 65.2% response rate. Weighting adjustments were then made to correct for differential sampling and response rates by racial groupings and type of cancer. All of the analyses used adjusted weights. RESULTS: The findings document the financial considerations (insurance, direct and indirect costs) as they relate to barriers to cancer treatment. Specific insurance premium-related barriers with regard to maintaining and affording coverage were more prevalent for blacks. Hispanics were less likely to have insurance coverage; however, more blacks reported being denied insurance coverage when they changed jobs compared with whites and Hispanics. Minorities, particularly Hispanics, were more likely to have experienced cost-related barriers associated with medications, diagnostic tests, and hospitalizations. In addition, Hispanics experienced significant out-of-pocket costs in paying for cancer treatment. CLINICAL IMPLICATIONS: This research shows the need for staff at cancer treatment facilities to be aware that there are nonclinical, financial factors that are important considerations in the treatment of cancer patients. Assessment of cancer patients during the diagnostic and treatment stages, possibly through case management, will provide information on potential barriers to treatment for individual patients. Hospital programs that reimburse out-of-pocket costs, transportation costs to obtain services, and lodging accommodations may be available. Additional services may be offered through cancer advocacy groups, such as the American Cancer Society and the National Coalition for Cancer Survivors, to assist patients with managing costs and overcoming barriers to care.

Information sources and barriers to cancer treatment by racial/ethnic minority status of patients.

BACKGROUND: This study examined the sources used by cancer patients to obtain helpful information regarding their treatment options and side effects and the major predictors that facilitated usage of information. METHODS: The survey was administered to a representative sample of cancer patients in Texas. The cancer treatment facilities from which the patients were sampled were part of the University of Texas M. D. Anderson Cancer Center's Texas Community Oncology Network. A total of 593 patients (65%) out of 910 contacted responded to the survey. RESULTS: The patients reported that providers such as physicians and nurses were the most helpful sources of information. White patients tended to use books and reference materials more heavily to gather additional information regarding their treatment, while black patients relied on pamphlets and television. Educational level appeared to have a major influence on the black patient's use of printed materials. CONCLUSIONS: The results document the important role that providers play in influencing patients' treatment decisions. Effective ways to communicate with cancer patients are different for patients with different racial backgrounds. Implications for the future development of patient education materials and cancer prevention initiatives targeting ethnic minorities are addressed.

Cultural sensitivity and readability of breast and prostate printed cancer education materials targeting African Americans.

Cancer prevention materials such as pamphlets, booklets, and fact sheets play a significant role in reducing cancer disparities. Little is documented in the literature about the cultural sensitivity of materials targeting African Americans. The Cancer Prevention Materials and African Americans project was conducted to assess the cultural sensitivity and readability of printed cancer education materials targeting African Americans. Results showed current breast and cancer materials are not written at appropriate reading levels, and only 54% of the breast and 40% of the prostate cancer materials were found to be culturally sensitive. Even though the materials are being developed and disseminated in health fairs, physician offices, barber shops, and other locations, the materials are still not reflective of the African-American populations and do not consider literacy, visual, written messages, and format as factors in their utilization. Future studies should assess the appropriateness of materials for African Americans to promote and prevent cancer in African Americans.

Transportation as a barrier to cancer treatment.

PURPOSE: Patients with cancer must overcome many psychological, social, and economic barriers to obtain needed treatment. Because of the need for repeated visits for cancer treatment on either an outpatient or an inpatient basis, one of the major issues that patients with cancer must confront is that of arranging for transportation to care. METHODS: This study compares the distance and mode of transportation to radiotherapy and chemotherapy and perceptions of transportation as a barrier to care among white, black, and Hispanic cancer patients receiving treatment from a consortium of cancer treatment facilities in Texas. A mail questionnaire was developed to assess the perceived barriers to cancer treatment for patients who had been diagnosed clinically with breast, colon, cervical, or prostate cancer, or lymphoma between 1989 and 1993. A total of 910 surveys were mailed to prospective participants. Of the surveys mailed, 593 were returned, yielding a 65.2% response rate. By race, the respondents included whites (42%), blacks (40%), Hispanics (15%), and Asian-Pacific Islanders (3%). Two respondents were 17 years of age; the remaining respondents were 18 years or older. RESULTS: This study shows that some patients may forgo needed treatment because of problems with transportation. This was perceived as an issue more for minority patients than for white patients. Black and Hispanic patients consistently reported that barriers such as distance, access to an automobile, and availability of someone to drive them to the treatment center were potential major problems. The distance to the facilities was farther for whites than for blacks and Hispanics. Patients generally had to travel farther for chemotherapy than for radiotherapy. CLINICAL IMPLICATIONS: Patients, particularly minorities, may opt to forgo needed care in the absence of available and affordable means of transportation to treatment facilities. These findings demonstrate the need for healthcare providers to be aware of the transportation problems that patients with cancer experience in obtaining treatment. Healthcare providers must work with patients, their families, and volunteer agencies in the community to facilitate transportation to cancer treatment services.

Role of receptor binding in toxicity, immunogenicity, and adjuvanticity of Escherichia coli heat-labile enterotoxin.

The role of receptor binding in the toxicity, immunogenicity, and adjuvanticity of the heat-labile enterotoxin of Escherichia coli (LT) was examined by comparing native LT and LT(G33D), a B-subunit receptor binding mutant, with respect to the ability to bind to galactose and to GM1, toxicity on mouse Y-1 adrenal tumor cells, the ability to stimulate adenylate cyclase in Caco-2 cells, enterotoxicity in the patent mouse model, and oral immunogenicity and adjuvanticity. In contrast to native LT, LT(G33D) was unable to bind to the galactosyl moiety of Sepharose 4B or GM1 but did retain the lectin-like ability to bind to immobilized galactose on 6% agarose beads. LT(G33D) had no enterotoxicity in the patent mouse model but exhibited residual toxicity on mouse Y-1 adrenal tumor cells and had an ability equivalent to that of native LT to stimulate adenylate cyclase in Caco-2 cells (5,000 versus 6,900 pmol per mg of protein). In addition, LT(G33D) was unable to serve as an effective oral adjuvant for induction of immunoglobulin G or A directed against a coadministered antigen. Furthermore, LT(G33D) elicited negligible serum and mucosal antibody responses against itself. These data indicate that the toxicity, immunogenicity, and oral adjuvanticity of LT are dependent upon binding of the B subunit to ganglioside GM1.

The readability levels of cancer-prevention materials targeting African Americans.

BACKGROUND: Several studies have examined the readability levels of cancer-prevention materials, but the readability levels of materials targeting African Americans have not been documented. The Cancer Prevention Materials and African-Americans project, funded in 1994 by the Texas Cancer Council, was developed to assess the readability levels and cultural sensitivity of cancer-prevention materials targeting African Americans. METHODS: This study assessed the readability of 100 cancer-prevention materials using McLaughlin's SMOG grading. Illustrations and point sizes were also examined by research staff members. RESULTS: Seventy-two percent of the material contained illustrations and 88% were printed using a 12-point font. An overall mean SMOG grade of 9.32 was found, which suggests that ninth graders can read and comprehend the text. CONCLUSIONS: Although this grade level is lower than those indicated by previous studies, many of the printed materials may not be appropriate for African Americans at high risk for cancer: those with low incomes and little education. Health professionals should focus on decreasing the reading levels of print materials, pretesting audiences to determine their actual reading levels, and examining other factors that influence readability and comprehension.

The role of informal and formal social support networks for patients with cancer.

PURPOSE: In this study, the authors examined the role of informal and formal social support networks in mitigating barriers to cancer treatment among whites, blacks, and Hispanics, based on a representative sample of cancer patients in Texas. DESCRIPTION OF STUDY: The sample frame for this study was obtained from the University of Texas M. D. Anderson Cancer Center's Texas Community Oncology Network, a consortium of cancer treatment facilities in Texas. Of the 910 patients who were contacted, 593 (65%) responded to the survey. RESULTS: The results show the value of social support networks in assisting cancer patients with continuing treatment. An important finding indicated that health professionals do not provide information regarding social support groups to patients with cancer at the time of diagnosis. Fewer than half of the respondents were asked whether they would be interested in joining a formal social support group. Individuals of all racial/ethnic groups reported that the formal support groups provided emotional assistance. Minorities were more apt to report that the formal support groups helped with continuing treatment. In addition, informal social support networks, such as extended families and civic clubs, were seen as more helpful for blacks and Hispanics as compared with whites. CLINICAL IMPLICATIONS: The need for formal and informal networks is indicated by the results of this study, which show that networks, such as relationships with family, friends, and relatives, play an important role in assisting patients in coping with their cancer. These networks are part of the patient's total treatment experience and must be acknowledged by healthcare professionals. A large number of patients are not asked to join social support groups, suggesting a need for training healthcare professionals to provide information regarding the potential benefits of support groups for cancer patients.

Barriers to cancer treatment: a review of published research.

PURPOSE/OBJECTIVES: To review published research on barriers to cancer treatment to provide a foundation for subsequent research and program and policy development directed at diminishing these barriers. DATA SOURCES: Relevant literature from medical and behavioral science data bases published between 1964 and 1994. Researchers reviewed 752 abstracts; they identified 160 articles that related directly to research on barriers to cancer treatment. Of these 160 articles, researchers chose 61 for a subsequent review using criteria to evaluate the strength of the study design and sampling procedures. DATA SYNTHESIS: The major barriers consistently documented to influence whether or not patients with cancer sought or continued treatment included communication problems between patients and providers, lack of information on side effects, cost of treatment, difficulties in obtaining and maintaining insurance coverage, and absence of social support networks. Access barriers generally were greater for older women, members of minority groups, and patients of lower socioeconomic status. The vast majority of the studies were conceptual or descriptive in nature and were based on nonprobability clinic-based samples. CONCLUSIONS: The limitations of existing research point to the need for studies on barriers to cancer treatment based on analytic population-based study designs that examine the relative importance of factors derived from multivariate explanatory models. This information may be used to develop programs and policies to ameliorate treatment barriers for patients with cancer. IMPLICATIONS FOR NURSING PRACTICE: The research priorities set forth by the Oncology Nursing Society also indicate a need for this type of research because quality of life, cost containment, and outcomes assessment all are directly or indirectly affected by the timely diagnosis of cancer. Treatment barriers have the potential to significantly affect an individual's ability to seek care and ultimately to increase the cost of care associated with adverse outcomes that may result from delays in seeking treatment.

Health expenditures in Texas during 1989 and 1990.

To monitor the growth of the health-care sector in Texas, we made annual estimates of aggregate health spending in 1989 and 1990 and compared them with estimates from prior years and with national trends. Expenditures are grouped by total spending, spending by the state government, and distribution of payment. To achieve data that could be compared with national figures, we followed the methods used by the federal government to estimate national health spending. Results indicate a return to the rapid rates of growth experienced in the early 1980s. Possible explanations for some major trends in spending and in sources of payment are provided. Basic features of recent efforts to contain costs are addressed and related to the trends.

Health expenditures in Texas, 1988.

Expenditures for health care in Texas during 1988 totaled $32.4 billion. Health spending by category of service and sources of payment was estimated and compared with estimates for prior years and with national trends. Texas differed from the nation as a whole in average annual increases in total spending, the percentage of spending for prepayment and administration, and the percentage of spending paid by consumers, the federal government, and private insurance. Proposed expansions in insurance coverage for the large proportion of uninsured Texans will probably require strong efforts to contain costs.