Recruiting a prospective community cohort to study Alzheimer's disease and structural and social determinants of health among adults racialized as Black: The ARCHES cohort

INTRODUCTION

This ongoing, prospective study examines the effectiveness of methods used to successfully recruit and retain 238 Black older adults in a longitudinal, observational Alzheimer's disease (AD) study.

METHODS

Recruitment strategies included traditional media, established research registries, speaking engagements, community events, and snowball sampling. Participants were asked to complete an annual office testing session, blood-based biomarker collection, optional one-time magnetic resonance imaging (MRI) scan, and community workshop.

RESULTS

Within the first 22 months of active recruitment, 629 individuals expressed interest in participating, and 238 enrolled in the ongoing study. Of the recruitment methods used, snowball sampling, community events, and speaking engagements were the most effective.

DISCUSSION

The systemic underrepresentation of Black participants in AD research impacts the ability to generalize research findings and determine the effectiveness and safety of disease-modifying treatments. Research to slow, stop, or prevent AD remains a top priority but requires diversity in sample representation.

Highlights

Provide flexible appointments in the evening or weekends, offering transportation assistance, and allowing participants to complete study visits at alternative locations, such as senior centers or community centers.Continuously monitor and analyze recruitment data to identify trends, challenges, and opportunities for improvement.Implement targeted strategies to recruit participants who are underrepresented based on sex, gender, or education to increase representation.Diversify the research team to include members who reflect the racial and cultural backgrounds of the target population, to enhance trust and rapport with prospective participants.

Racial/ethnic differences in the relationship between wealth and health across young adulthood

•Wealth attenuated racial differences in self-rated health during young adulthood.•Wealth had consistent incremental effect on health among White & Hispanic Americans.•For Black Americans, wealth was protective of health in the highest wealth quartile.•Individual wealth, not parental wealth was associated with health among Hispanics.

The complex relationship between depression and progression to incident cognitive impairment across race and ethnicity

INTRODUCTION

We examined baseline differences in depression and antidepressant use among cognitively normal older adults in five ethnoracial groups and assessed whether depression predicted a faster progression to incident cognitive impairment across groups.

METHODS

Data from the National Alzheimer's Coordinating Center (n = 8168) were used to examine differences between non-Hispanic Whites (nHW), African Americans (AA), Hispanics, Asians, and American Indian and Alaskan Natives in cross-sectional and longitudinal models.

RESULTS

AA had a lower risk of depression compared to nHW at baseline. No statistical interactions were noted between ethnoracial groups and depression. However, depression independently predicted a faster progression to incident cognitive impairment. Hispanics and Asian participants had a higher hazard for progression compared to nHW.

DISCUSSION

Previously established risk factors between depression and dementia were not found among AA and nHW participants. The relationship between depression and ethnoracial groups is complex and suggests differential effects on progression from cognitive normality to impairment.

Cash Transfers and Health

Financial resources are known to affect health outcomes. Many types of social policies and programs, including social assistance and social insurance, have been implemented around the world to increase financial resources. We refer to these as cash transfers. In this article, we discuss theory and evidence on whether, how, for whom, and to what extent purposeful cash transfers improve health. Evidence suggests that cash transfers produce positive health effects, but there are many complexities and variations in the outcomes. Continuing research and policy innovation-for example, universal basic income and universal Child Development Accounts-are likely to be productive.

"Down in the Sewers": Perceptions of Depression and Depression Care Among African American Men

Depression is one of the most common, costly, and debilitating psychiatric disorders in the United States. One of the most persistent mental health disparities is the underutilization of treatment services among African American men with depression. Little is known about appropriateness or acceptability of depression care among African American men. The purpose of this study was to examine perceptions of depression and determine barriers to depression treatment among African American men. A series of four focus groups were conducted with 26 African American men. The average age of the sample was 41 years and most participants reported that they had completed high school. Nearly half of the participants reported that they are currently unemployed and most had never been married. The most common descriptions of depression in this study were defining depression as feeling down, stressed, and isolated. A small group of participants expressed disbelief of depression. The majority of participants recognized the need to identify depression and were supportive of depression treatment. Nonetheless, most men in this sample had never sought treatment for depression and discussed a number of barriers to depression care including norms of masculinity, mistrust of the health care system, and affordability of treatment. Men also voiced their desire to discuss stress in nonjudgmental support groups. Research findings highlight the need to increase the awareness of symptoms some African American men display and the need to provide appropriate depression treatment options to African American men.

Quality Over Quantity: Integrating Mental Health Assessment Tools into Primary Care Practice

Depression is one of the most common, costly, and debilitating psychiatric disorders in the US. There are also strong associations between depression and physical health outcomes, particularly chronic diseases such as diabetes mellitus. Yet, mental health services are underutilized throughout the US. Recent policy changes have encouraged depression screening in primary care settings. However, there is not much guidance about how depression screeners are administered. There are people suffering from depression who are not getting the treatment they need. It is important to consider whether enough care is being taken when administering depression screeners in primary care settings.

Racial Discrimination, John Henryism, and Depression Among African Americans

Evidence from previous studies indicates that racial discrimination is significantly associated with depression and that African Americans with higher levels of socioeconomic status (SES) report greater exposure to racial discrimination compared to those with lower SES levels. Coping strategies could alter the relationship between racial discrimination and depression among African Americans. This study first examined whether greater levels of SES were associated with increased reports of racial discrimination and ratings of John Henryism, a measure of high-effort coping, among African Americans. Second, we examined whether high-effort coping moderated the relationship between racial discrimination and depression. Data were drawn from the National Survey of American Life Reinterview (n = 2,137). Analyses indicated that greater levels of education were positively associated with racial discrimination (p < .001) and increased levels of racial discrimination were positively related to depression (p < .001), controlling for all sociodemographic factors. Greater levels of John Henryism were associated with increased odds of depression but there was no evidence to suggest that the relationship between discrimination and depression was altered by the effects of John Henryism.

Racial Discrimination, John Henryism, and Depression Among African Americans

Evidence from previous studies indicates that racial discrimination is significantly associated with depression and that African Americans with higher levels of socioeconomic status (SES) report greater exposure to racial discrimination compared to those with lower SES levels. Coping strategies could alter the relationship between racial discrimination and depression among African Americans. This study first examined whether greater levels of SES were associated with increased reports of racial discrimination and ratings of John Henryism, a measure of high-effort coping, among African Americans. Second, we examined whether high-effort coping moderated the relationship between racial discrimination and depression. Data were drawn from the National Survey of American Life Reinterview (n = 2,137). Analyses indicated that greater levels of education were positively associated with racial discrimination (p < .001) and increased levels of racial discrimination were positively related to depression (p < .001), controlling for all sociodemographic factors. Greater levels of John Henryism were associated with increased odds of depression but there was no evidence to suggest that the relationship between discrimination and depression was altered by the effects of John Henryism.

"Racism?!?… Just Look at Our Neighborhoods": Views on Racial Discrimination and Coping Among African American Men in Saint Louis

Recent events in Ferguson underscore the need to better understand the unique challenges, stressors, and coping mechanisms of African American men. To this end, a focus group study was conducted in Saint Louis, a few miles from Ferguson. Although numerous stress-related themes were discussed, racial discrimination and structural racism emerged as pervasive stressors among these men. Participants described experiences of discrimination in multiple settings including workplace, school, and residential, and within the criminal justice system. Coping strategies included not only drinking and smoking but also religiosity and familial support. Men also mentioned that they found relief in simply discussing their stressors in a group setting. One implication of this study is to develop and implement group support models for this population.

Development of health diagnostics based on personalized medical models

Due to rapid evolution of new technologies the concept of personalized medicine has evolved. Components include molecular biology, proteomics, metabolomic analysis, genetic testing, and molecular medicine for diagnostics. In addition to diagnostics these methods can be used to determine individual susceptibility to diseases and conditions. In conjunction with new diagnostic methods, new therapies can be tailored to the individual. These new technologies present a challenge in terms of the expansion of the medical record as well as the development of new methods for creating disease profiles. This article focuses on a computer-aided support for personalized medicine. Specific approaches are explored that permit automated data analysis for prognosis and treatment based on analysis methods for numeric and pictorial data. Although personalized medicine based on the genome of the patient are occasionally performed, because of the large amount of data new methods are needed to form general disease models as well as specific profiles of the individual patient.

Relationship between abuse and neglect in childhood and diabetes in adulthood: differential effects by sex, national longitudinal study of adolescent health

INTRODUCTION

Few studies have investigated links between child abuse and neglect and diabetes mellitus in nationally representative samples, and none have explored the role of obesity in the relationship. We sought to determine whether child abuse and neglect were associated with diabetes and if so, whether obesity mediated this relationship in a population-representative sample of young adults.

METHODS

We used data from 14,493 participants aged 24 to 34 years from Wave IV of the National Longitudinal Study of Adolescent Health to study associations between self-reported child abuse (sexual, physical, or emotional abuse) and neglect as children and diabetes or prediabetes in young adulthood. We conducted sex-stratified logistic regression analyses to evaluate associations in models before and after the addition of body mass index (BMI) as a covariate.

RESULTS

Although the prevalence of diabetes was similar for men and women (7.0% vs 6.7%), men were more likely than women to have prediabetes (36.3% vs 24.6%; omnibus P < .001). Among men, recurrent sexual abuse (≥3 lifetime incidents) was significantly associated with diabetes (OR, 3.66; 95% CI, 1.31-10.24), but not with prediabetes. There was no evidence of mediation by BMI. No forms of child abuse or neglect were associated with diabetes or prediabetes among women.

CONCLUSIONS

Recurrent sexual abuse is robustly associated with diabetes in young adult men, independently of other forms of child abuse or neglect and BMI. Future research should explore other potential mechanisms for this association to identify avenues for prevention of diabetes among men who have experienced sexual abuse.

Subjective religiosity, church attendance, and depression in the National Survey of American Life

Studies have consistently indicated that blacks report lower rates of depression than whites. This study examined the association between religion and depression and whether religion explained lower rates of depression among blacks compared to whites. Data were drawn from the National Survey of American Life, a multi-ethnic sample of African Americans, Caribbean Blacks, and non-Hispanic whites (n = 6,082). African Americans and Caribbean Blacks reported higher mean levels of subjective religiosity than whites, but there were no significant differences in levels of church attendance. African Americans (OR 0.54; CI 0.45-0.65) and Caribbean Blacks (OR 0.66; CI 0.48-0.91) reported significantly lower odds of depression than whites. Differences in subjective religiosity and church attendance did not account for the association between major depression and African American and Caribbean Black race/ethnicity relative to whites. More research is needed to examine whether there are other factors that could protect against the development of depression.

Race, life course socioeconomic position, racial discrimination, depressive symptoms and self-rated health

Greater levels of socioeconomic position (SEP) are generally associated with better health. However results from previous studies vary across race/ethnicity and health outcomes. Further, the majority of previous studies do not account for the effects of life course SEP on health nor the effects of racial discrimination, which could moderate the effects of SEP on health. Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, we examined the relationship between a life course SEP measure on depressive symptoms and self-rated health. A life course SEP was constructed for each participant, using a framework that included parental education and occupation along with respondents' highest level of education and occupation. Interaction terms were created between life course SEP and racial discrimination to determine whether the association between SEP and health was moderated by experiences of racial discrimination. Analyses revealed that higher levels of life course SEP were inversely related to depressive symptoms. Greater life course SEP was positively associated with favorable self-rated health. Racial discrimination was associated with more depressive symptoms and poorer self-rated health. Analyses indicated a significant interaction between life course SEP and racial discrimination on depressive symptoms in the full sample. This suggested that for respondents with greater levels of SEP, racial discrimination was associated with reports of more depressive symptoms. Future research efforts should be made to examine whether individuals' perceptions and experiences of racial discrimination at the interpersonal and structural levels limits their ability to acquire human capital as well as their advancement in education and occupational status.

Differences in the clinical recognition of depression in diabetes patients: the Diabetes Study of Northern California (DISTANCE)

BACKGROUND

It is unknown to what extent the gap between need and care for depression among patients with diabetes differs across racial/ethnic groups. We compared, by race/ethnicity, the likelihood of clinical recognition of depression (diagnosis or treatment) of patients who reported depressive symptoms in a well-characterized community-based population with diabetes.

DESIGN

We used a survey follow-up study of 20,188 patients with diabetes from Kaiser Permanente Northern California. Analyses were limited to 910 patients who scored 10 or higher on the Patient Health Questionnaire (PHQ-8) which was included in the survey and who had no clinical recognition of depression in the 12 months prior to survey. Clinical recognition of depression was defined by a depression diagnosis, referral to mental health services, or antidepressant medication prescription.

RESULTS

Among the 910 patients reporting moderate to severe depressive symptoms on the survey and who had no clinical recognition in the prior year, 12%, 8%, 8%, 14%, and 15% of African American, Asian, Filipino, Latino, and white patients, respectively, were clinically recognized for depression in the subsequent 12 months. After adjusting for sociodemographics, limited English proficiency, and depressive symptom severity, racial/ethnic minorities were less likely to be clinically recognized for depression compared with whites (relative risk: Filipino: 0.30, African American: 0.62).

CONCLUSIONS

More work is needed to understand the modifiable patient and provider factors that influence clinical recognition of depression among diabetes patients from different racial/ethnic groups, and the potential impact of low rates of clinical recognition on quality of care.

Are benefits conferred with greater socioeconomic position undermined by racial discrimination among African American men?

BACKGROUND: conventional wisdom suggests that increased socioeconomic resources should be related to better health. Considering the body of evidence demonstrating the significant association between racial discrimination and depression, we examined whether exposure to racial discrimination could attenuate the positive effects of increased levels of socioeconomic position (SEP) among African Americans. Specifically, this paper investigated the joint interactive effects of SEP and racial discrimination on the odds of depression among African Americans. METHODS: racial discrimination was measured using two measures, major and everyday discrimination. Study objectives were achieved using data from the National Survey of American Life, which included a nationally representative sample of African Americans (n =3570). Logistic regression models were used to estimate the effects of SEP and racial discrimination on the odds of depression. RESULTS: reports of racial discrimination were associated with increased risk of depression among American African men who possessed greater levels of education and income. Among African American men, significant, positive interactions were observed between education and experiences of major discrimination, which were associated with greater odds of depression (P = 0.02). Additionally, there were positive interactions between income and both measures of racial discrimination (income x everyday discrimination, P = 0.013; income x major discrimination, P = 0.02), which were associated with increased odds of depression (P = 0.02). CONCLUSIONS: it is possible that experiences of racial discrimination could, in part, diminish the effects of increased SEP among African American men.

The relationship between socioeconomic position and depression among a US nationally representative sample of African Americans

PURPOSE

Findings from previous studies have not revealed significant, inverse relationships between socioeconomic position (SEP) and depression among African Americans. This study examined the relationship between multiple indicators of SEP and Major Depressive Episode (MDE) among African Americans.

METHODS

Data were drawn from the National Survey of American Life main interview and re-interview. MDE, at both 12 month and lifetime intervals, was assessed using the World Mental Health version of the Composite International Diagnostic Interview. Logistic regression models were adjusted for demographics.

RESULTS

For 12-month MDE, household income and unemployment predicted greater odds of MDE among African American men, while there was an inverse relationship between education and 12-month MDE. Only unemployment was significantly associated with lifetime MDE among African American men. For African American women, a significant inverse relationship between household income and 12-month MDE was observed.

CONCLUSIONS

Findings garnered from this study indicate that it is important to consider multiple measures of SEP in the prediction of depression among African Americans, and that the pattern of association between SEP and depression varies according to sex. Considering the paucity of studies that have explored the relationship between SEP and depression, additional research is needed to more firmly establish the relationship between SEP and depression. It is also important to consider stressors that may affect the relationship between SEP and depression among African Americans.

Discrimination, Mastery, and Depressive Symptoms Among African American Men

PURPOSE

This study examines the influence of discrimination and mastery on depressive symptoms for African American men at young (18-34), middle (35-54), and late (55+) adulthood.

METHOD

Analyses are based on responses from 1,271 African American men from the National Survey of American Life (NSAL).

RESULTS

Discrimination was significantly related to depressive symptoms for men ages 35 to 54 and mastery was found to be protective against depressive symptoms for all men. Compared to African American men in the young and late adult groups, discrimination remained a statistically significant predictor of depressive symptoms for men in the middle group once mastery was included.

IMPLICATIONS

Findings demonstrate the distinct differences in the influence of discrimination on depressive symptoms among adult African American males and the need for future research that explores the correlates of mental health across age groups. Implications for social work research and practice with African American men are discussed.

The expression of xenobiotic-metabolizing enzymes in human prostate and in prostate epithelial cells (PECs) derived from primary cultures

BACKGROUND

Dietary heterocyclic amines (HCAs) are carcinogenic in rodent prostate requiring activation by enzymes such as cytochrome P450 (CYP) and N-acetyltransferase (NAT).

METHODS

We investigated by Western blotting and immunohistochemistry the expression of CYP1A1, CYP1A2, and NAT1 in human prostate and in prostate epithelial cells (PECs) derived from primary cultures and tested their ability to activate the dietary carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and its N-hydroxy metabolite (N-OH-IQ) to DNA-damaging moieties.

RESULTS

Western blotting identified CYP1A1, CYP1A2, and NAT1. Immunohistochemistry localized NAT1 to the cytoplasm of PECs. Inter-individual variation was observed in the expression levels of CYP1A1, 1A2, and NAT1 (11, 75, and 35-fold, respectively). PECs expressed CYP1A1 and NAT1 but not CYP1A2. When incubated with IQ or N-OH-IQ, PECs formed DNA adducts indicating their ability to metabolically activate these compounds.

CONCLUSIONS

Prostate cells possess the capacity to activate dietary carcinogens. PECs may provide a useful model system to study their role in prostate carcinogenesis.

Prostate epithelial stem cells

The prostate gland is the site of the most commonly diagnosed cancer in men in USA and UK, accounting for one in five of new cases of male cancer. Common with many other cancer types, prostate cancer is believed to arise from a stem cell that shares characteristics with the normal stem cell. Normal prostate epithelial stem cells were recently identified and found to have a basal cell phenotype together with expression of CD133. Preliminary data have now emerged for a prostate cancer stem cell that also expresses cell surface CD133 but lacks expression of the androgen receptor. Here we examine the evidence supporting the existence of prostate cancer stem cells and discuss possible mechanisms of stem cell maintenance.

Intelligent agent model for remote support of rural healthcare for the elderly

With the aging population, the number of individuals requiring long-term care is expected to dramatically increase in the next twenty years, placing an increasing burden on healthcare. Many patients are admitted to assisted living facilities at a fairly early stage due to their inability to perform normal daily living activities. The purpose of this study is to determine if the use of technology for both monitoring and intervention can permit elderly patients to remain in their homes for longer periods of time with the benefit of the comfort of familiar surroundings while at the same time reducing the burden on caregivers. In addition, remote access to healthcare can improve monitoring of the patient's physical and mental condition and involve the patient in his or her own care. The home monitoring and intervention system is based on intelligent agent methodology developed by the authors.

Epithelial stem cells in human prostate growth and disease

Benign prostatic hyperplasia and prostate cancer arise as a consequence of changes in the balance between cell division and differentiation. Little, however, is known about the control of this process. Stem cells are a small population of cells that divide occasionally to produce transit-amplifying cells that in turn produce the differentiated cell types of the tissue. It is believed that cancer cell proliferation is also driven by stem cells. We have shown that around one in 200 prostate epithelial cells have characteristics of stem cells and that these cells are contained within a population with a distinct keratin expression pattern. Work is now ongoing to identify markers for these cells that will allow us to study the role they play in prostatic disease.

Heart rate and blood pressure responses to tobacco smoking among African-American adolescents

Ethnic differences in both physiological response to and health consequences of tobacco smoking-some of which have been attributed to ethnic preferences for menthol cigarettes-have been described in the literature. We compared acute physiological responses to smoking in African-American and European-American adolescent menthol cigarette smokers seeking smoking cessation treatment. One-hundred- twenty-eight adolescents (32% African-American, 71% female; mean age 15.16 +/- 1.32 years, mean Fagerström Test of Nicotine Dependence (FTND) score 6.73 +/- 1.53, cigarettes per day (CPD) 16.9 +/- 2.64) participated in an experimental session during which they smoked one menthol cigarette of their usual brand. Blood pressure, heart rate, and exhaled carbon monoxide (CO) concentrations were measured before and after smoking; mean puff volume (mL), puff duration (sec) and maximal puff velocity (mL/sec) during smoking were also determined. Two sample t-tests were performed to assess ethnic differences in smoking topography; analysis of covariance was used to determine whether heart rate and blood pressure after smoking one menthol cigarette varied by ethnicity, after controlling for baseline physiological measures. No significant ethnic differences were observed in either smoking topography or acute cardiovascular response to smoking. These preliminary findings warrant extension to a broader group of nontreatment-seeking adolescent smokers of both ethnicities.

Non-linear analysis using continuous chaotic modeling

Recent research in nanotechnology is opening exciting new avenues not only for understanding the human body but also for creating devices that can effectively interact with it to alleviate the effects of disease. These new developments present both challenges and opportunities for adaptation of existing methodologies to create new approaches for analysis and modeling of nanotechnology-based systems. The concept of continuous chaotic modeling presents an avenue for a paradigm shift away from traditional digital computing to take advantage of analog models that are more compatible with biological systems. The theoretical basis of continuous chaotic modeling is summarized, followed by illustrations of applications of this methodology.

The role of networks and artificial intelligence in nanotechnology design and analysis

Techniques with their origins in artificial intelligence have had a great impact on many areas of biomedicine. Expert-based systems have been used to develop computer-assisted decision aids. Neural networks have been used extensively in disease classification and more recently in many bioinformatics applications including genomics and drug design. Network theory in general has proved useful in modeling all aspects of biomedicine from healthcare organizational structure to biochemical pathways. These methods show promise in applications involving nanotechnology both in the design phase and in interpretation of system functioning.

Inclusion of signal analysis in a hybrid medical decision support system

OBJECTIVES

Signal analysis has played an important role in cardiac diagnosis, both as a separate entity and in conjunction with clinical parameters. Hybrid systems are an effective method for developing higher-order decision models in which biomedical signal data can be incorporated.

METHODS

The hybrid system components include a knowledge-based system that utilizes approximate reasoning techniques, a neural network model based on a potential function approach to supervised learning that uses the general class of Cohen orthogonal functions as potential functions, and a signal analysis component that relies on continuous chaotic modeling to produce a degree of variability in the time series. The hybrid system is illustrated in an application for differentiation among different types of dementia.

RESULTS

Application of this method to cardiac diagnosis shows that chaotic parameters alone contribute significantly to correct classification while the addition of clinical parameters increases the sensitivity, specificity, and accuracy. Applications to electroencephalogram analysis indicate that the second-order difference plots display significant differences for the different types of EEG waves identifiable by frequency, both in shape and degree of dispersion. Hence the identification of these waves, and the duration of their occurrence, may provide suitable variables for chaotic analysis.

CONCLUSIONS

Results from studies in cardiology demonstrate that using chaotic measures for ECG analysis provide useful information for classification. Sensitivity, specificity, and accuracy are increased if these methods are combined with other clinical parameters in a hybrid system. This approach has been extended to new applications based on EEG analysis combined with other relevant information.

The use of consequential reasoning in cancer chemotherapy

Knowledge-based decision support systems traditionally rely on condition-action rule structures, an adequate representation for simple decisions. In complex domains an important part of decision-making includes analysis of the consequences of a decision. Consequential reasoning is particularly important in medicine as potential risk and/or benefit can be included. In this paper, a knowledge structure and inference engine is described that permits the representation and analysis of consequential reasoning in a computer-assisted decision support system. The use of consequential reasoning is then illustrated in an application designed to assist in cancer chemotherapy decisions. The result is a method that is sensitive to individual patient reactions to chemotherapy agents, permitting an individualized approach to therapy. Individualized drug therapy is becoming increasingly feasible due to advances made in the field of genomics. The system is structured so that new information can be incorporated easily. Although the application shown here is to chemotherapy, the general methodology can be used in any area in which the consequences should significantly influence the decision.

A novel mechanism of matrix metalloproteinase-9 gene expression implies a role for keratinization

To investigate the pathophysiological role of matrix metalloproteinase (MMP)-9 in the skin, we analyzed MMP-9 expression from human keratinocytes in culture. MMP-9 and the terminal differentiation marker involucrin were co-localized in the same keratinocytes with a high concentration of Ca(2+), a potent stimulator of differentiation. We identified the novel KRE-M9 element, further downstream to the previously reported TPA responsive element in the MMP-9 promoter, and both of these two elements were shown to be important for MMP-9 transcription and Ca(2+) induction. The concomitant upregulation of MMP-9 and involucrin transcripts was probably due to the very similar gene regulatory elements, KRE-M9 and KRE-4, in their respective promoters. These results indicate a novel mechanism of transcriptional regulation for MMP-9 in the process of keratinization, implying the probable association of apoptosis and differentiation of keratinocytes in epidermal skin tissue.

Epithelial cell differentiation pathways in the human prostate: identification of intermediate phenotypes by keratin expression

The prostate grows slowly throughout adult life, leading to benign prostatic hyperplasia (BPH), which often results in urethral obstruction in later years. The symptoms of BPH are the second most common reason for surgery in men over 65. The aim of this study was to determine the relationship between cell proliferation and cell differentiation in BPH tissue. Using multiple antibodies, simultaneously detected with different fluorophore-conjugated secondary antibodies, several subpopulations of epithelial cells were detected. In addition to K14, basal cells also expressed keratins 15, 17, and 19 in various combinations, and some of the luminal cells also expressed K19 together with K8 and K18. Co-staining for cytokeratins and Ki-67 indicated that 44% of proliferative cells expressed K14 and 36% K19, although the difference was not statistically significant. This report provides a detailed description of the relationship between keratin expression and cell proliferation in the prostate and indicates that K19-positive cells form the link between the basal and luminal layers of the epithelium. (J Histochem Cytochem 49:271-278, 2001)

Proliferative heterogeneity in the human prostate: evidence for epithelial stem cells

Clonal analysis of human prostate epithelial cells was undertaken in order to identify stem cells. Two types of colony were distinguished, termed type I and type II. Type I colonies were relatively small and irregular and contained a loose mixture of differentiated and undifferentiated cells. In contrast, type II colonies were large, round, and homogeneous, consisting almost exclusively of small undifferentiated and dividing cells. The colony-forming efficiency was 5.8% +/- 1.8 for freshly isolated epithelial cells. There were approximately 10 times as many type I as type II colonies and about 1 in 200 of the plated cells was capable of forming a type II colony. In three-dimensional culture on Matrigel, the type II colonies produced structures reminiscent of prostate epithelium, with luminal cells expressing markers of prostate epithelial differentiation, including the androgen receptor. On the basis of their proliferative characteristics and pluripotency, the type II colonies may be the progeny of stem cells and the type I colonies of a more differentiated transit-amplifying population.

Bone morphogenetic protein 1 is an extracellular processing enzyme of the laminin 5 gamma 2 chain

Epithelial cells maintained in culture medium containing low calcium proteolytically process laminin 5 (alpha3beta3gamma2) within the alpha3 and gamma2 chains (). Experiments were designed to identify the enzyme(s) responsible for the laminin 5 processing and the sites of proteolytic cleavage. To characterize the nature of laminin 5 processing, we determined the N-terminal amino acid sequences of the proteolytic fragments produced by the processing events. The results indicate that the first alpha3 chain cleavage (200-l65 kDa alpha3) occurs within subdomain G4 of the G domain. The second cleavage (l65-l45 kDa alpha3) occurs within the lIla domain, 11 residues N-terminal to the start of domain II. The gamma chain is cleaved within the second epidermal growth factor-like repeat of domain Ill. The sequence cleaved within the gamma2 chain matches the consensus sequence for the cleavage of type I, II, and III procollagens by bone morphogenetic protein-1 (BMP-1), also known as type I procollagen C-proteinase (). Recombinant BMP-1 cleaves gamma2 in vitro, both within intact laminin 5 and at the predicted site of a recombinant gamma2 short arm. alpha3 is also cleaved by BMP-1 in vitro, but the cleavage site is yet to be determined. These results show the laminin alpha3 and gamma2 chains to be substrates for BMP-1 in vitro. We speculate that gamma2 cleavage is required for formation of the laminin 5-6 complex and that this complex is directly involved in assembly of the interhemidesmosomal basement membrane. This further suggests that BMP-1 activity facilitates basement membrane assembly, but not hemidesmosome assembly, in the laminin 5-rich dermal-epidermal junction basement membrane in vivo.

Comparison of marker protein expression in benign prostatic hyperplasia in vivo and in vitro

OBJECTIVE

To use multiple immunofluorescence to compare the in vivo and in vitro expression of tissue-specific proteins in BPH. Materials and methods Pure populations of prostate epithelial and stromal cells were produced using standard methods. Serum-free media for epithelial cells were compared. Co-localization of proteins was compared in frozen-tissue sections and cultured cells by simultaneous multiple immunofluorescence, and recorded using a high-resolution charge-coupled device camera.

RESULTS

In contrast to the other serum-free media tested, epithelial cells grew without squamous differentiation or vacuolation in prostate epithelial growth medium (PrEGM, Clonetics, BioWhittaker UK Ltd., Berks, UK). These cells were predominantly of a basal phenotype, with some cells showing a luminal phenotype. Most of the stromal cells had features of myofibroblasts, but smooth muscle cells and fibroblasts also were present.

CONCLUSION

PrEGM is a commercially available serum-free medium in which primary cultures of prostate epithelial cells can be propagated reproducibly. This study provides a comprehensive description of tissue-specific protein expression in BPH in vivo and in vitro. The use of simultaneous multiple immunofluorescence to study co-localization has resulted in a more precise definition of phenotype than has previously been possible, thereby establishing the relevance of the in vitro model system BPH.

The role of the Internet in medical decision making

The Internet has dramatically changed the means by which information is obtained. Accurate, up-to-date information is vital to maintain the quality of healthcare, especially as US healthcare delivery changes to a primary care-based system. The availability of this new and potentially vast source of information also affects strategies for medical decision making. In this article, use of online information in our medical center is discussed, together with the impact of a locally-developed decision support system. This system first contained components for differential diagnosis as well as computer-assisted instruction. Initially, online searching was limited to Medline literature searches. This component has now been expanded to include important new tools for accessing medical information on the Internet.

Complete primary structure of two splice variants of collagen XII, and assignment of alpha 1(XII) collagen (COL12A1), alpha 1(IX) collagen (COL9A1), and alpha 1(XIX) collagen (COL19A1) to human chromosome 6q12-q13

Overlapping cDNA clones that encode the full-length human alpha 1(XII) collagen polypeptides were isolated. The long variant molecule cDNA of 9750 nucleotides (nt) contains a 9189-nt open reading frame encoding 3063 amino acid residues. The short variant molecule cDNA of 6258 nt contains a 5697-nt open reading frame encoding 1899 amino acid residues. At the amino terminus of each variant is a 24-residue signal peptide that is followed by the mature polypeptides of 3039 amino acid residues with a calculated molecular mass of 330,759 Da for the long variant and 1875 amino acid residues with a calculated molecular mass of 203,163 Da for the short variant polypeptide. The human collagen XII chains are predicted to have all the structural domains described for the molecules in chicken and mouse, including, fibronectin type III repeats, von Willebrand factor A domains, and two triple-helical domains similar to those of all the other collagen family members. The amino acid residue sequence of human alpha 1(XII) collagen showed 92% identity to the mouse chain and 78% identity to the chicken chain. The sequence of three peptide fragments of collagen XII isolated from human placenta was identical to the sequence predicted from the deduced cDNA sequence and confirms that the cDNA encodes human alpha 1(XII) collagen. An isolated genomic clone was used to map the locus of the COL12A1 gene to chromosome 6q12-q13, very close to the locus of the FACIT collagen genes COL9A1 and COL19A1. RT-PCR on a variety of cDNAs demonstrates that both variant transcripts appear in human amnion, chorion, skeletal muscle, small intestine, and in cell cultures of human dermal fibroblasts, keratinocytes, and endothelial cells. Only the small variant transcript is apparent in human lung, placenta, kidney, and a squamous cell carcinoma cell line. These results confirm the previous observations showing that collagen XII is found in collagen I-containing tissues.

Loss of plectin causes epidermolysis bullosa with muscular dystrophy: cDNA cloning and genomic organization

Plectin is a widely expressed high molecular weight protein that is involved in cytoskeleton-membrane attachment in epithelial cells, muscle, and other tissues. The human autosomal recessive disorder epidermolysis bullosa with muscular dystrophy (MD-EBS) shows epidermal blister formation at the level of the hemidesmosome and is associated with a myopathy of unknown etiology. Here, plectin was found to be absent in skin and cultured keratinocytes from an MD-EBS patient by immunofluorescence and immunoprecipitation, suggesting that plectin is a candidate gene/protein system for MD-EBS mutation. The 14800-bp human plectin cDNA was cloned and sequenced. The predicted 518-kD polypeptide has homology to the actin-binding domain of the dystrophin family at the amino terminus, a central rod domain, and homology to the intermediate filament-associated protein desmoplakin at the carboxyl terminus. The corresponding human gene (PLEC1), consisting of 33 exons spanning >26 kb of genomic DNA was cloned, sequenced, and mapped to chromosomal band 8q24. Homozygosity by descent was observed in the consanguineous MD-EBS family with intragenic plectin polymorphisms. Direct sequencing of PCR-amplified plectin cDNA from the patient's keratinocytes revealed a homozygous 8-bp deletion in exon 32 causing a frameshift and a premature termination codon 42 bp downstream. The clinically unaffected parents of the proband were found to be heterozygous carriers of the mutation. These results establish the molecular basis of MD-EBS in this family and clearly demonstrate the important structural role for plectin in cytoskeleton-membrane adherence in both skin and muscle.

Altered expression of CD44 isoforms in squamous-cell carcinomas and cell lines derived from them

CD44 is a transmembrane glycoprotein that binds hyaluronan, extracellular matrix proteins and growth factors. Multiple isoforms of CD44 are generated by alternative splicing of 10 separate exons (V1-V10). Expression of the variable exons has been correlated with tumour progression and metastasis in a range of cell types. However, multiple CD44 isoforms are expressed by normal stratified squamous epithelia, such as the epidermis and the lining of the oral cavity. The purpose of our study was to examine CD44 expression in squamous-cell carcinomas (SCC). By immunofluorescence we found reduced expression of one or more of the variant exons in a series of 13 oral SCC, with loss being most common in poorly differentiated tumours. Of the exons we examined, V3 was lost most frequently, but otherwise there was no consistent pattern as to which exons (V4/5, 6, 8) were missing. We also studied CD44 expression in a range of SCC lines, using Western blotting and semi-quantitative RT-PCR. All lines showed reduced expression of the terminal differentiation marker involucrin. Two lines showed selective loss of the largest forms of CD44 and one failed to express any of the variant exons. These cell lines, therefore, provide a useful experimental model with which to study the biological significance of exon loss in SCC.

CD44 is the major peanut lectin-binding glycoprotein of human epidermal keratinocytes and plays a role in intercellular adhesion

Although binding of peanut agglutinin (PNA) to keratinocytes is often used as a marker of terminal differentiation, the identity of the PNA-binding glycoproteins has been unclear. We now show that an antiserum raised against the glycoproteins recognises isoforms of CD44, the most abundant of which could be labelled with [35S]sulphate, indicating the presence of glycosaminoglycan side chains. RT-PCR analysis showed that keratinocytes expressed at least 5 forms of CD44 containing different numbers of exons from the variable region of the extracellular domain and also expressed the standard ‘haemopoietic’ form of CD44 which lacks the variable exons. Standard and variant isoforms of CD44 were expressed both by proliferating keratinocytes and cells undergoing terminal differentiation, although the level of CD44 mRNAs decreased when keratinocytes were placed in suspension to induce differentiation. The role of CD44 in intercellular adhesion was investigated by plating keratinocytes onto a rat pancreatic carcinoma line transfected with different CD44 isoforms. Keratinocyte adhesion to transfectants expressing variant exons 4–7 was greater than to cells expressing standard CD44 and could be inhibited with hyaluronan or digestion with hyaluronidase. These observations confirm earlier predictions that the PNA-binding glycoproteins of keratinocytes play a role in intercellular adhesion.

Integrin expression by human epidermal keratinocytes can be modulated by interferon-gamma, transforming growth factor-beta, tumor necrosis factor-alpha, and culture on a dermal equivalent

Receptors of the integrin family are largely confined to the basal layer of keratinocytes, both in human epidermis and in stratified cultures of human keratinocytes. However, suprabasal integrin expression is observed during epidermal wound healing and in psoriatic lesions. We have investigated potential stimuli of suprabasal expression. Addition of transforming growth factor-beta (TGF-beta), interferon-gamma (IFN-gamma), or tumor necrosis factor-alpha (TNF-alpha) to keratinocytes cultured with a 3T3 feeder layer did not induce suprabasal expression. The cytokines caused small changes in the levels of alpha 2 beta 1 or alpha 3 beta 1 on the surface of basal keratinocytes but had no significant effect on the proportion of cells adhering to fibronectin, type IV collagen, and laminin, and did not cause changes in the mobility of integrin subunits on polyacrylamide gels. Injection of TNF-alpha or IFN-gamma intradermally into healthy human volunteers induced an inflammatory response but did not induce suprabasal integrin expression. However, we did observe transient suprabasal integrin expression when keratinocytes were grown on a dermal equivalent consisting of fibroblasts in a collagen gel. One week after raising the cultures to the air-liquid interface, beta 1 integrins were found in all the viable cell layers, with suprabasal cells co-expressing integrins and involucrin; 1 week later integrins were confined to the basal layer. Addition of TGF-beta, IFN-gamma, or TNF-alpha to the dermal equivalents neither induced nor inhibited suprabasal integrin expression. We conclude that suprabasal integrin expression is not induced by the inflammatory cytokines tested, and instead may reflect the proliferation/differentiation status of the epidermis.

Information integration in a decision support system

Electronic medical records pose a challenge because of the complex types of data which are included. Decision support systems must be able to deal effectively with these data types. In the expert system demonstrated here, a diversity of data types are included. These data are processed by three different methods. However, the different methods of processing are transparent to the user. An overall rule-based interface integrates the different methods into one comprehensive system.

Evidence against a major role for integrins in calcium-dependent intercellular adhesion of epidermal keratinocytes

It is well established that integrins mediate keratinocyte adhesion to extracellular matrix proteins, but, in addition, there is some evidence that they mediate intercellular adhesion. We have investigated the role of integrins in keratinocyte-keratinocyte adhesion by adding anti-integrin antibodies to cells in three assays that differ according to the calcium ion concentration of the medium, the presence or absence of an adhesive substrate (glass or tissue culture plastic) and the timing of antibody addition. As previously reported by Larjava et al., (J. Cell Biol. 110:803-815), a monoclonal antibody to the beta 1 subunit perturbed cell-cell adhesion when added to adherent monolayers in low calcium medium (0.1 mM calcium ions), but did not prevent cell-cell adhesion or stratification induced by raising the level of calcium ions to 1.8mM (the concentration in standard medium). Monoclonal antibodies to both the alpha 3 and beta 1 subunits inhibited the attachment, spreading and motility of keratinocytes in low or standard calcium medium when added at the time of plating; however, they had only a modest effect on the accumulation of cells in adherent clusters. Aggregation of keratinocytes in suspension required a calcium ion concentration of greater than 0.1mM and was not inhibited by any of a large panel of anti-integrin antibodies, including three new antibodies that recognise alpha 2 beta 1. We conclude that any inhibitory effects of individual anti-integrin antibodies on cell-cell adhesion are abrogated by a calcium ion concentration above 0.1mM and that in low calcium medium at least some of the inhibition of cell-cell adhesion is a consequence of the inhibition of cell-substrate adhesion and motility.

Towards gene therapy for haemophilia B using primary human keratinocytes

Haemophilia B might be permanently cured by gene therapy--the introduction of a correct copy of the factor IX gene into the somatic cells of a patient. Here, we have introduced a recombinant human factor IX cDNA into primary human keratinocytes by means of a defective retroviral vector. In tissue culture, transduced keratinocytes were found to secrete biologically active factor IX and after transplantation of these cells into nude mice, human factor IX was detected in the bloodstream in small quantities for one week. This is the first demonstration of a therapeutic protein reaching the bloodstream from transduced primary keratinocytes. This may have implications for the treatment of haemophilia B and other disorders.

Characterisation of eight monoclonal antibodies to involucrin

Involucrin is a precursor of the insoluble protein envelope that is assembled in the outermost layers of the epidermis. The coding sequence of the protein contains a number of short tandem repeats that have been greatly altered during mammalian evolution. We have characterised eight mouse monoclonal antibodies raised against human involucrin, all of which bind to the protein in immunoprecipitation, immunoblot and immunohistochemical preparations. Each antibody was screened for cross-reactivity with gorilla, owl monkey, dog and pig involucrin and with a fragment of the human protein, expressed in lambda gt 11, that includes the entire early region of the modern segment of repeats. Three antibodies recognised involucrin in all of these assays. Four antibodies recognised primate involucrins and the lambda gt 11 fragment. One antibody, which showed cross-reactivity with lower molecular weight proteins, only recognised primate involucrins and therefore bound outside the early region of the modern segment. Since the antibodies can be used to detect involucrin both biochemically and histologically, in a range of species, they will have applications in further studies of the expression, function and evolution of the protein.

Mitogens induce calcium transients in both dividing and terminally differentiating keratinocytes

During terminal differentiation, keratinocytes lose the ability to divide. One indicator of responsiveness to certain growth factors is a transient rise in the intracellular concentration of free calcium ions ([Ca2+]i). The aim of our experiments was to discover whether or not terminally differentiating keratinocytes have lost the ability to exhibit an increase in [Ca2+]i in response to factors that stimulate [3H]thymidine incorporation and increase [Ca2+]i in undifferentiated keratinocytes. [Ca2+]i was measured with the calcium indicator dye FURA-2 and by a ratio imaging method. Expression of involucrin, a precursor of the keratinocyte cornified envelope, was used as a marker of terminal differentiation. Measurements were made on stratified colonies of cells grown in standard medium (containing 1.8 mM calcium ions) and on cell monolayers in low calcium medium (0.1 mM). Treatment of serum-starved monolayers with substance P, bombesin or complete growth medium containing 10% fetal calf serum resulted in increased [3H]thymidine incorporation. A switch from low calcium to standard medium also stimulated [3H]thymidine incorporation whether or not the cells had been serum-starved. In each experiment some cells showed an increase in [Ca2+]i while others did not. However, the heterogeneity in the [Ca2+]i response did not reflect the terminal differentiation status of individual cells: both involucrin-positive and -negative cells were found in the responding and nonresponding populations. Involucrin-positive and -negative areas of stratified cultures also underwent a transient increase in [Ca2+]i in response to serum-containing medium. Our data therefore indicate that both proliferating (involucrin-negative) and post-mitotic, terminally differentiating (involucrin-positive) keratinocytes can respond to mitogenic stimuli by an increase in [Ca2+]i.(ABSTRACT TRUNCATED AT 250 WORDS)

Neural network approach to detection of metastatic melanoma from chromatographic analysis of urine

Chromatographic analysis of sera or urine is important in medicine for the evaluation of patients whose clinical status is associated with the presence of specific biochemical markers. Malignant melanoma has been a model for such studies due to the elaboration of melanin precursors and pigment as the tumor metastasizes. Computer-assisted methods for categorizing chromatographic data and clinical status are imperative due to the large number of detectable compounds and possible correlations. In addition, computer-based analysis of the data can readily extract patterns that are not obvious by visual inspection. In this paper, we present a neural network analysis of melanoma chromatographic and clinical data that categorizes subjects into normals, NED patients (No Evidence of Disease), and metastatic patients. The set of marker compounds for metastatic disease represents a significant advance over the correlations derived by visual inspection.

DNA amplification is rare in normal human cells

Three types of normal human cells were selected in tissue culture with three drugs without observing a single amplification event from a total of 5 x 10(8) cells. No drug-resistant colonies were observed when normal foreskin keratinocytes were selected with N-(phosphonacetyl)-L-aspartate or with hydroxyurea or when normal mammary epithelial cells were selected with methotrexate. Some slightly resistant colonies with limited potential for growth were obtained when normal diploid fibroblast cells derived from fetal lung were selected with methotrexate or hydroxyurea but careful copy-number analysis of the dihydrofolate reductase and ribonucleotide reductase genes revealed no evidence of amplification. The rarity of DNA amplification in normal human cells contrasts strongly with the situation in tumors and in established cell lines, where amplification of oncogenes and of genes mediating drug resistance is frequent. The results suggest that tumors and cell lines have acquired the abnormal ability to amplify DNA with high frequency.

Onset of expression of peanut lectin-binding glycoproteins is correlated with stratification of keratinocytes during human epidermal development in vivo and in vitro

During gestation the epidermis develops from a single layer of ectoderm into a layer of keratinocytes overlaid by a layer of periderm; this is followed by a progressive increase in the number of layers of keratinocytes, until finally the distinct granular and cornified layers characteristic of mature epidermis are formed. As part of our investigation into the function of the peanut lectin-binding glycoproteins of cultured human keratinocytes, we have examined their expression at different stages of human epidermal development. We found that the onset of expression of the glycoproteins coincided with the transition from a two- to a three-layered epidermis, both in vivo and in organ culture. In adult epidermis, the patterns of binding of peanut lectin and Limax flavus lectin are complementary, with peanut binding more strongly to suprabasal keratinocytes and Limax flavus lectin binding more strongly to cells in the basal layer. We found that the complementary pattern of binding of the two lectins was established at, or shortly after, the onset of stratification and retained throughout development. In contrast, expression by keratinocytes of involucrin, a protein precursor of the cornified envelope, occurred after stratification had begun. Finally, we identified the peanut lectin-binding glycoproteins of adult epidermis by immunoblotting with an antiserum raised against the glycoproteins of cultured neonatal keratinocytes. In conclusion, expression of the peanut lectin-binding glycoproteins is an early event in epidermal development, and this would be consistent with a role for the glycoproteins in stratification.