The value of lost productivity from workplace bullying in Ireland

BACKGROUND

Workplace bullying is a pervasive problem with significant personal, social and economic costs. Estimates of the resulting lost productivity provide an important societal perspective on the impact of the problem. Understanding where these economic costs fall is relevant for policy.

AIMS

We estimated the value of lost productivity to the economy from workplace bullying in the public and private sectors in Ireland.

METHODS

We used nationally representative survey data and multivariable negative binomial regression to estimate the independent effect of workplace bullying on days absent from work. We applied the human capital approach to derive an estimate of the annual value of lost productivity due to bullying by sector and overall, in 2017.

RESULTS

Bullying was independently associated with an extra 1.00 (95% CI: 0.38-1.62) days absent from work over a 4-week period. This differed for public and private sector employees: 0.69 (95% CI: -0.12 to 1.50) versus 1.45 (95% CI: 0.50-2.40) days respectively. Applying official data, we estimated the associated annual value of lost productivity to be €51.8 million in the public sector, €187.6 million in the private sector and €239.3 million overall.

CONCLUSIONS

The economic value of lost productivity from workplace bullying in Ireland is significant. Although bullying is more prevalent in the public sector, it has a larger effect on absence in the private sector. Given this, along with the greater overall share of employees, productivity losses from bullying are considerably larger in the private sector in Ireland.

Influenza vaccine uptake and attitudes of healthcare workers in Ireland

BACKGROUND

Influenza vaccination uptake by Irish healthcare workers remains sub-optimal despite local initiatives to increase it.

AIMS

To investigate hospital workers' attitudes to influenza vaccination and how this influenced their decisions about vaccination.

METHODS

A questionnaire survey of Irish hospital workers, measuring uptake of and attitudes to influenza vaccination.

RESULTS

There were 747 responders, of whom 361 (48%) reported having received influenza vaccination. Attitudes predicting vaccination uptake included a belief that vaccination would protect family members (P < 0.0005, CI 1.191-1.739), a perception of susceptibility to 'flu (P < 0.0005, CI 1.182-1.685), a belief that all healthcare workers should be vaccinated (P < 0.005, CI 1.153-1.783), perceived ease of getting 'flu vaccination at work (P < 0.0005, CI 1.851-2.842) and encouragement by line managers (P < 0.05, CI 1.018-1.400). Attitudes negatively associated with vaccination uptake included fear of needles (P < 0.05, CI 0.663-0.985) and a belief that vaccination would cause illness (P < 0.0005, CI 0.436-0.647). Medical staff were significantly more likely to be vaccinated. Healthcare students were least likely to be vaccinated (P < 0.0005).

CONCLUSION

Addressing specific barriers to influenza vaccination in healthcare workers may improve uptake.

Dimensionality and R4P: A Health Equity Framework for Research Planning and Evaluation in African American Populations

Introduction Existing health disparities frameworks do not adequately incorporate unique interacting contributing factors leading to health inequities among African Americans, resulting in public health stakeholders' inability to translate these frameworks into practice. Methods We developed dimensionality and R4P to integrate multiple theoretical perspectives into a framework of action to eliminate health inequities experienced by African Americans. Results The dimensional framework incorporates Critical Race Theory and intersectionality, and includes dimensions of time-past, present and future. Dimensionality captures the complex linear and non-linear array of influences that cause health inequities, but these pathways do not lend themselves to approaches to developing empirically derived programs, policies and interventions to promote health equity. R4P provides a framework for addressing the scope of actions needed. The five components of R4P are (1) Remove, (2) Repair, (3) Remediate, (4) Restructure and (5) Provide. Conclusion R4P is designed to translate complex causality into a public health equity planning, assessment, evaluation and research tool.

The Prevalence of Respiratory Symptoms in Irish Dairy Farmers

Work-related respiratory disease is a significant risk in the farming community. We assessed respiratory symptoms using a validated work-related respiratory questionnaire in 126 dairy farmers (19-75 years; 91.3% male). The prevalence of cough symptoms was 34.4%. Thirty-seven farmers (29.4%) complained of upper airway symptoms while forty (31.7%) complained of eye problems. Cumulated symptoms scores did not indicate higher than normal rates of chronic lung disease. Only 10 farmers (7.9%) were taking medication for lung conditions. Only 7 (5.6%) were current smokers. The rate of respiratory symptoms did not relate to the herd size or the method of animal feeding used by the farmers. The incidence of respiratory symptoms remains high among Irish dairy farmers. While the exact reason for this is unknown it may be related to continuing work- related dust exposure.

Low maternal adherence to a Mediterranean diet is associated with increase in methylation at the MEG3-IG differentially methylated region in female infants

Diet is dictated by the surrounding environment, as food access and availability may change depending on where one lives. Maternal diet during pregnancy is an important part of the in utero environment, and may affect the epigenome. Studies looking at overall diet pattern in relation to DNA methylation have been lacking. The Mediterranean diet is known for its health benefits, including decreased inflammation, weight loss, and management of chronic diseases. This study assesses the association between maternal adherence to a Mediterranean diet pattern during pregnancy and infant DNA methylation at birth. Mediterranean diet adherence in early pregnancy was measured in 390 women enrolled in the Newborn Epigenetic Study, and DNA methylation was assessed in their infants at birth. Multinomial logistic regression was used to assess the association between adherence to a Mediterranean diet and infant methylation at the MEG3, MEG3-IG, pleiomorphic adenoma gene-like 1, insulin-like growth factor 2 gene, H19, mesoderm-specific transcript, neuronatin, paternally expressed gene 3, sarcoglycan and paternally expressed gene 10 regions, measured by pyrosequencing. Infants of mothers with a low adherence to a Mediterranean diet had a greater odds of hypo-methylation at the MEG3-IG differentially methylated region (DMR). Sex-stratified models showed that this association was present in girls only. This study provides early evidence on the association between overall diet pattern and methylation at the 9 DMRs included in this study, and suggests that maternal diet can have a sex-specific impact on infant DNA methylation at specific imprinted DMRs.

Disparities in infant mortality and effective, equitable care: are infants suffering from benign neglect?

Quality care for infant mortality disparity elimination requires services that improve health status at both the individual and the population level. We examine disparity reduction due to effective care and ask the following question: Has clinical care ameliorated factors that make some populations more likely to have higher rates of infant mortality compared with other populations? Disparities in postneonatal mortality due to birth defects have emerged for non-Hispanic black and Hispanic infants. Surfactant and antenatal steroid therapy have been accompanied by growing disparities in respiratory distress syndrome mortality for black infants. Progesterone therapy has not reduced early preterm birth, the major contributor to mortality disparities among non-Hispanic black and Puerto Rican infants. The Back to Sleep campaign has minimally reduced SIDS disparities among American Indian/Alaska Native infants, but it has not reduced disparities among non-Hispanic black infants. In general, clinical care is not equitable and contributes to increasing disparities.

Spatial distribution of mortality by homicide and social inequalities according to race/skin color in an intra-urban Brazilian space

INTRODUCTION

In Brazil, deaths by external causes rank first in the mortality statistics. Nevertheless, studies which investigate the relationship between mortality by external causes and race/skin color are scarce.

OBJECTIVES

To evaluate the relative contribution of race/skin color to the spatial distribution of mortality by homicide in Salvador, state of Bahia, Brazil, in the period 1998 - 2003.

MATERIAL AND METHODS

This is a spatial aggregate study including secondary data on 5,250 subjects, using a unit of analysis called the "weighting area" (WA). Annual average death rates by homicide were estimated. The Global and Local Moran Index were used to evaluate the presence of spatial autocorrelation and the Conditional Auto Regressive (CAR) model was employed to evaluate the referred effect, using the R statistical package.

RESULTS

Global and Local Moran's I tests were significant. CAR regression showed that the predicted mortality rate increases when there is a growth in the proportion of black males aged between 15 and 49 years. Geometrically weighted regression (GWR) showed a very small variation of the local coefficients for all predictors.

CONCLUSION

We demonstrated that the interrelation between race, violence and space is a phenomenon which results from a long process of social inequality. Understanding these interactions requires interdisciplinary efforts that contribute to advancement of knowledge that leads to more specific Public Health interventions.

Calpain activation through galectin-3 inhibition sensitizes prostate cancer cells to cisplatin treatment

Prostate cancer will develop chemoresistance following a period of chemotherapy. This is due, in part, to the acquisition of antiapoptotic properties by the cancer cells and, therefore, development of novel strategies for treatment is of critical need. Here, we attempt to clarify the role of the antiapoptotic molecule galectin-3 in prostate cancer cells using siRNA and antagonist approaches. The data showed that Gal-3 inhibition by siRNA or its antagonist GCS-100/modified citrus pectin (MCP) increased cisplatin-induced apoptosis of PC3 cells. Recent studies have indicated that cisplatin-induced apoptosis may be mediated by calpain, a calcium-dependent protease, as its activation leads to cleavage of androgen receptor into an androgen-independent isoform in prostate cancer cells. Thus, we examined whether calpain activation is associated with the Gal-3 function of regulating apoptosis. Here, we report that Gal-3 inhibition by siRNA or GCS-100/MCP enhances calpain activation, whereas Gal-3 overexpression inhibits it. Inhibition of calpain using its inhibitor and/or siRNA attenuated the proapoptotic effect of Gal-3 inhibition, suggesting that calpain activation may be a novel mechanism for the proapoptotic effect of Gal-3 inhibition. Thus, a paradigm shift for treating prostate cancer is suggested whereby a combination of a non-toxic anti-Gal-3 drug together with a toxic chemotherapeutic agent could serve as a novel therapeutic modality for chemoresistant prostate cancers.

Perceived discrimination and depressive symptoms, smoking, and recent alcohol use in pregnancy

BACKGROUND

Perceived discrimination is associated with poor mental health and health-compromising behaviors in a range of vulnerable populations, but this link has not been assessed among pregnant women. We aimed to determine whether perceived discrimination was associated with these important targets of maternal health care among low-income pregnant women.

METHODS

Face-to-face interviews were conducted in English or Spanish with 4,454 multiethnic, low-income, inner-city women at their first prenatal visit at public health centers in Philadelphia, Penn, USA, from 1999 to 2004. Perceived chronic everyday discrimination (moderate and high levels) in addition to experiences of major discrimination, depressive symptomatology (CES-D >or= 23), smoking in pregnancy (current), and recent alcohol use (12 months before pregnancy) were assessed by patients' self-report.

RESULTS

Moderate everyday discrimination was reported by 873 (20%) women, high everyday discrimination by 238 (5%) women, and an experience of major discrimination by 789 (18%) women. Everyday discrimination was independently associated with depressive symptomatology (moderate = prevalence ratio [PR] of 1.58, 95% CI: 1.38-1.79; high = PR of 1.82, 95% CI: 1.49-2.21); smoking (moderate = PR of 1.19, 95% CI: 1.05-1.36; high = PR of 1.41, 95% CI: 1.15-1.74); and recent alcohol use (moderate = PR of 1.23, 95% CI: 1.12-1.36). However, major discrimination was not independently associated with these outcomes.

CONCLUSIONS

This study demonstrated that perceived chronic everyday discrimination, but not major discrimination, was associated with depressive symptoms and health-compromising behaviors independent of potential confounders, including race and ethnicity, among pregnant low-income women.

A roadmap for authentic community/academic engagement for developing effective community preterm birth education

Evidence-based care, behavioral interventions, and new technologies applied during the perinatal period are insufficient by themselves to reduce or eliminate racial/ethnic disparities in infant mortality. Traditional health and behavioral interventions, and the structures through which they are delivered, do not facilitate adherence to behavioral or health recommendations at home or in the community. The translation of research into practice in the absence of community involvement often results in interventions that are irrelevant to community needs, insensitive to existing culture, inconsistent with the resources available, and strain existing community assets. Using a community-partnered participatory research (CPPR) process, the Healthy African American Families project in Los Angeles developed a multilevel, risk communications strategy to promote awareness about preterm birth in the local community. This paper provides a roadmap, giving insight into the CPPR model and processes involved in the development of the risk communications strategy.

Closing the Black-White gap in birth outcomes: a life-course approach

In the United States, Black infants have significantly worse birth outcomes than White infants. Over the past decades, public health efforts to address these disparities have focused primarily on increasing access to prenatal care, however, this has not led to closing the gap in birth outcomes. We propose a 12-point plan to reduce Black-White disparities in birth outcomes using a life-course approach. The first four points (increase access to interconception care, preconception care, quality prenatal care, and healthcare throughout the life course) address the needs of African American women for quality healthcare across the lifespan. The next four points (strengthen father involvement, systems integration, reproductive social capital, and community building) go beyond individual-level interventions to address enhancing family and community systems that may influence the health of pregnant women, families, and communities. The last four points (close the education gap, reduce poverty, support working mothers, and undo racism) move beyond the biomedical model to address the social and economic inequities that underlie much of health disparities. Closing the Black-White gap in birth outcomes requires a life course approach which addresses both early life disadvantages and cumulative allostatic load over the life course.

Closing the Black-White gap in birth outcomes: a life-course approach

In the United States, Black infants have significantly worse birth outcomes than White infants. Over the past decades, public health efforts to address these disparities have focused primarily on increasing access to prenatal care, however, this has not led to closing the gap in birth outcomes. We propose a 12-point plan to reduce Black-White disparities in birth outcomes using a life-course approach. The first four points (increase access to interconception care, preconception care, quality prenatal care, and healthcare throughout the life course) address the needs of African American women for quality healthcare across the lifespan. The next four points (strengthen father involvement, systems integration, reproductive social capital, and community building) go beyond individual-level interventions to address enhancing family and community systems that may influence the health of pregnant women, families, and communities. The last four points (close the education gap, reduce poverty, support working mothers, and undo racism) move beyond the biomedical model to address the social and economic inequities that underlie much of health disparities. Closing the Black-White gap in birth outcomes requires a life course approach which addresses both early life disadvantages and cumulative allostatic load over the life course.

The Healthy African American Families' risk communications initiative: using community partnered participatory research to address preterm birth at the local level

Preterm birth is the leading cause of infant death for African Americans and is significantly associated with lifelong morbidity. Primary prevention efforts using medical strategies to reduce the rates of preterm birth have been unsuccessful. Using community partnered participatory processes, the Healthy African American Families project in Los Angeles developed a multilevel, risk communications strategy to promote awareness about preterm birth in the local community. Participants included community members, community-based organizations, local government, healthcare providers, and national-level advocates. The initiative focused on increasing social support for pregnant women, providing current information on preterm birth risks, and improving quality of health services. The initiative includes components addressing community education, mass media, provider education, and community advocacy. Products include 100 Intentional Acts of Kindness toward a Pregnant Woman, a doorknob brochure on signs and symptoms of preterm labor, and an education manual on preterm birth and other African American health issues. Cooperation, affiliation, and community self-help were key aspects of the planning process and the health promotion products. Additional community benefits included increased leadership and skills development. The process and products described here may be useful in other communities and for addressing other health outcomes in communities of color.

Exposure to chronic stress and ethnic differences in rates of bacterial vaginosis among pregnant women

OBJECTIVE

The purpose of this study was to assess the contribution of chronic social stressors to race/ethnic differences in the rate of bacterial vaginosis among pregnant women in the inner-city area.

STUDY DESIGN

We conducted a cross-sectional clinical prevalence study in a sample of 2304 women at the first prenatal visit (14.8 +/- 0.2 weeks of gestation). Bacterial vaginosis was diagnosed by Nugent's method. Stress was measured at the individual and community levels with the use of interviews and administrative records. Logistic regression was used to assess the effects of stress on the odds of bacterial vaginosis occurrence, after adjustment for demographic and behavioral risk.

RESULTS

Black women had significantly higher rates of bacterial vaginosis (64%) compared with white women (35%). Exposure to chronic stressors at the individual level differed by race (eg, 32% of the black women reported threats to personal safety compared with 13% of white women). There were significant racial differences in exposure to stress at the community level (eg, 63% of the black women lived in neighborhoods with aggravated assault rates that were above the citywide mean compared with 25% of the white women). After the adjustment for sociodemographic, behavioral risk, and perceived stress, the odds of the occurrence of bacterial vaginosis that was associated with the community level stressor of "homelessness" was significant (odds ratio, 6.7; 95% CI, 1.6-27.8). Inclusion of both individual and community level stressors reduced the black/white bacterial vaginosis odds ratio by 27%.

CONCLUSION

Stressful exposures are associated positively with bacterial vaginosis in pregnancy in a sample of women of low income in the inner city. The measurement of stressors at multiple levels explained a significant proportion of the racial disparity in the rates of occurrence of bacterial vaginosis.

Indications for therapy and treatment recommendations for bacterial vaginosis in nonpregnant and pregnant women: a synthesis of data

Accumulating evidence has associated bacterial vaginosis (BV) with serious medical complications such as premature delivery. The present article synthesizes available data on the treatment of nonpregnant and pregnant women with BV to prevent preterm delivery. A literature search identified articles published since 1976 that evaluated treatment of BV. An intention-to-treat sensitivity analysis was performed, to better compare studies. Studies that evaluated therapy efficacy varied with regard to diagnostic criteria, patient characteristics, clinicians, and laboratories. Therapies varied in efficacy for cure 4 or more weeks after therapy, from 48% to 85%. Intervention studies to reduce BV-related adverse outcomes of pregnancy differed in populations studied, medication used, type of therapy (oral or intravaginal), and timing of treatment. The benefit of treating women at high risk with oral metronidazole has been shown in several studies; however, the effect of treating women without a history of premature delivery is unclear. The use of intravaginal clindamycin therapy, especially during the latter half of the second trimester and thereafter, appears to increase infections during the neonatal period.

Stress, infection and preterm birth: a biobehavioural perspective

Preterm birth is currently the most important problem in maternal-child health in the United States. Epidemiological studies have suggested that two factors, maternal stress and maternal urogenital tract infection, are significantly and independently associated with an increased risk of spontaneous preterm birth. These factors are also more prevalent in the population of sociodemographically disadvantaged women who are at increased risk for preterm birth. Studies of the physiology of parturition suggest that neuroendocrine and immune processes play important roles in the physiology and pathophysiology of normal and preterm parturition. However, not all women with high levels of stress and/or infection deliver preterm, and little is understood about factors that modulate susceptibility to pathophysiological events of the endocrine and immune systems in pregnancy. We present here a comprehensive, biobehavioural model of maternal stress and spontaneous preterm delivery. According to this model, chronic maternal stress is a significant and independent risk factor for preterm birth. The effects of maternal stress on preterm birth may be mediated through biological and/or behavioural mechanisms. We propose that maternal stress may act via one or both of two physiological pathways: (a) a neuroendocrine pathway, wherein maternal stress may ultimately result in premature and/or greater degree of activation of the maternal-placental-fetal endocrine systems that promote parturition; and (b) an immune/inflammatory pathway, wherein maternal stress may modulate characteristics of systemic and local (placental-decidual) immunity to increase susceptibility to intrauterine and fetal infectious-inflammatory processes and thereby promote parturition through pro-inflammatory mechanisms. We suggest that placental corticotropin-releasing hormone may play a key role in orchestrating the effects of endocrine and inflammatory/immune processes on preterm birth. Moreover, because neuroendocrine and immune processes extensively cross-regulate one another, we further posit that exposure to both high levels of chronic stress and infectious pathogens in pregnancy may produce an interaction and multiplicative effect in terms of their combined risk for preterm birth. Finally, we hypothesise that the effects of maternal stress are modulated by the nature, duration and timing of occurrence of stress during gestation. A discussion of the components of this model, including a theoretical rationale and review of the available empirical evidence, is presented. A major strength of this biobehavioural perspective is the ability to explore new questions and to do so in a manner that is more comprehensive than has been previously attempted. We expect findings from this line of proposed research to improve our present state of knowledge about obstetric risk assessment for preterm birth by determining the characteristics of pregnant women who are especially susceptible to stress and/or infection, and to broaden our understanding of biological (endocrine, immune, and endocrine-immune interactions) mechanisms that may translate social adversity during pregnancy into pathophysiology, thereby suggesting intervention strategies.

Decreased galectin-3 expression in prostate cancer

BACKGROUND

Galectin-3 is a carbohydrate-binding protein whose level of expression has been shown to be correlated with metastatic potential in a number of different tumor types. The purpose of this investigation was to examine galectin-3 expression in several tumorigenic and nontumorigenic prostate cell lines and prostate tissue samples.

METHODS

The expression of galectin-3 in cell lines and tissue samples was evaluated by tissue immunohistochemistry and Western blot analysis.

RESULTS

Human cell lines PC-3M, PC-3, DU-145, PrEC-1, and MCF10A demonstrated the presence of galectin-3. Galectin-3 was not detected in TSU-pr1 and LNCaP by Western blot analysis. We furthered our studies by examining a series of human prostate tissue samples for expression of galectin-3. Overall, approximately 60-70% of the normal tissue examined demonstrated heterogenous expression of galectin-3. In stage II tumors, however, there was a dramatic decrease in galectin-3 expression in both PIN and tumor sections, with only 10.5% (2/19) of these samples expressing this protein. Stage III tumors also demonstrated a decreased expression of galectin-3, although this downregulation was not as dramatic, with 35% of PIN samples and 52% of tumor tissue expressing galectin-3 (P < 0.01).

CONCLUSIONS

These data demonstrate that galectin-3 is downregulated in prostate cancer. The altered downregulation pattern of galectin-3 observed between tumor stages suggests different roles for galectin-3 in the progression of prostate cancer.

The NH2 terminus of galectin-3 governs cellular compartmentalization and functions in cancer cells

Galectin-3 is a member of the beta-galactoside-binding protein family shown to be involved in tumor progression and metastasis. It has a unique primary structure consisting of three domains: a 12-amino acid leader sequence containing a casein kinase I serine phosphorylation site, which is preceded by a collagenase-sensitive Pro-Gly-rich motif, and a COOH-terminal half encompassing the carbohydrate-binding site. To study the functional role of the unusual leader sequence of galectin-3, a mutant cDNA that causes an 11-amino acid deletion in the NH2-terminal region was generated and expressed in galectin-3-null BT-549 human breast carcinoma cells. Deletion of the NH2 terminus resulted in abolition of the secretion of truncated galectin-3, loss of nuclear localization, and reduced carbohydrate-mediated functions compared with the wild-type protein. When green fluorescent protein was fused to the galectin-3 leader sequence and transiently transfected into BT-549 cells, the uniform cellular distribution of native green fluorescent protein was changed mainly to a nuclear pattern. To further investigate whether the functional changes observed in a galectin-3 with the 11 NH2-terminal amino acids deleted were due to loss of phosphorylation at Ser6, two point mutations were created at this serine: Ser6-->Ala and Ser6-->Glu. No obvious difference was observed in cellular localization between wild-type and Ser6-mutated transfectants. These results suggest a structural role for the NH2 terminus leader motif of galectin-3 in determining its cellular targeting and biological functions independent of phosphorylation.

Inhibition of spontaneous metastasis in a rat prostate cancer model by oral administration of modified citrus pectin

BACKGROUND

Prostate cancer is the most common cancer diagnosed in U.S. men and remains incurable once it has metastasized. Many stages of the metastatic cascade involve cellular interactions mediated by cell surface components, such as carbohydrate-binding proteins, including galactoside-binding lectins (galectins). Modified citrus pectin (pH-modified), a soluble component of plant fiber derived from citrus fruit, has been shown to interfere with cell-cell interactions mediated by cell surface carbohydrate-binding galectin-3 molecules.

PURPOSE

The aim of this study was to determine whether modified citrus pectin, a complex polysaccharide rich in galactosyl residues, could inhibit spontaneous metastasis of prostate adenocarcinoma cells in the rat.

METHODS

The ability of modified citrus pectin to inhibit the adhesion of Dunning rat prostate cancer MAT-LyLu cells to rat endothelial cells was measured by 51Cr-labeling. Modified citrus pectin inhibition of MAT-LyLu cell anchorage-independent growth was measured by colony formation in agarose. The presence of galectin-3 in rat MAT-LyLu cells and human prostate carcinoma was demonstrated by immunoblotting and immunohistochemistry. One million MAT-LyLu cells were injected subcutaneously into the hind limb of male Copenhagen rats on day 0. Rats were given 0.0%, 0.01%, 0.1%, or 1.0% (wt/vol) modified citrus pectin continuously in their drinking water (from day 4 until necropsy on day 30). The number of MAT-LyLu tumor colonies in the lungs were counted.

RESULTS

Compared with 15 or 16 control rats that had lung metastases on day 30, seven of 14 rats in the 0.1% and nine of 16 rats in the 1.0% modified citrus-pectin group had statistically significant (two-sided; P < .03 and P < .001, respectively) reductions in lung metastases. The lungs of the 1.0% modified citrus pectin-treated rats had significantly (two-sided; P < .05) fewer metastatic colonies than control groups (9 colonies +/- 4 [mean +/- SE] in the control group compared with 1 colony +/- 1 in the treated group). Modified citrus pectin had no effect on the growth of the primary tumors. In vitro, modified citrus pectin inhibited MAT-LyLu cell adhesion to rat endothelial cells in a time- and dose-dependent manner as well as their colony formation in semisolid medium.

CONCLUSIONS

We present a novel therapy in which oral intake of modified citrus pectin acts as a potent inhibitor of spontaneous prostate carcinoma metastasis in the Copenhagen rat.

IMPLICATIONS

Further investigations are warranted to determine the following: 1) the role of galectin-3 in normal and cancerous prostate tissues and 2) the ability of modified citrus pectin to inhibit human prostate metastasis in nude mice.

Structure-function relationship of a recombinant human galactoside-binding protein

A galactoside-binding lectin (hL-31) containing a collagen-like sequence was identified in human tumor cells. It was found to be the homologue of the IgE-binding protein, the macrophage cell-surface Mac-2 antigen, and the murine CBP35, RL-29, and mL-34 lectins. Here we report on the expression in Escherichia coli and functional analysis of recombinant hL-31 (rhL-31). The rhL-31 was purified in one step through an asialofetuin affinity column. The rhL-31 was reactive to anti-lectin antibodies and retained its lactose-dependent hemagglutination of trypsin-treated glutaraldehyde-fixed rabbit erythrocytes. The rhL-31 elutes from an affinity column as a 31-kDa monomer and undergoes homodimerization at relatively high protein concentrations, comparable to those used to mediate hemagglutination. Electron microscopy showed that the rhL-31 appears as a Y-shaped structure. Lactoperoxidase-catalyzed iodination of murine tumor cell-surface proteins followed by collagenase treatment revealed that the lectin is probably a peripheral membrane protein whereby both the amino and the carboxy termini are exposed on the outer cell membrane. These results point to the membrane disposition and orientation of the lectin and suggest a mechanism for a structure-function relationship of lectin activity.

Purification of human tumor cell autocrine motility factor and molecular cloning of its receptor

Tumor autocrine motility factor (AMF) has been detected in and purified from serum-free conditioned medium of human HT-1080 fibrosarcoma cells. Under nonreducing conditions, AMF migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single band of 55 kDa but under reducing conditions as a band of 64 kDa. Two-dimensional polyacrylamide gel electrophoresis of the purified AMF resolved two groups of polypeptides with isoelectric points of 6.1 and 6.2 (majors), 6.35 and 6.4 (minors). Purified AMF stimulated HT-1080 cell migration in a dose-dependent fashion. The motility stimulation of the fibrosarcoma cells with AMF is associated with the phosphorylation of the AMF receptor, a 78-kDa cell surface glycoprotein (gp78), suggesting protein kinase participation in migratory signal transduction. The gene encoding gp78 was cloned from an HT-1080 fibrosarcoma complementary DNA library. The deduced sequence encodes a polypeptide of 323 amino acids. The nucleotide and predicted amino acid sequence of the gp78 reveals significant homology with the human suppressor/oncogene p53 protein.

Purification of B16-F1 melanoma autocrine motility factor and its receptor

Tumor autocrine motility factor (AMF) is a cytokine which stimulates both random and directed cell migration by self-producing cells. AMF has been detected in and purified from serum-free conditioned medium of murine B16-F1 melanoma cells. Under nonreducing conditions AMF migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single band of Mr 55,000, whereas under reducing conditions it migrates as a single polypeptide of Mr 64,000. Two-dimensional polyacrylamide gel electrophoresis of the purified AMF resolved two polypeptides with isoelectric points of 6.35 (major) and 6.4 (minor). No carbohydrate side chains were detected in the B16-F1 AMF. Purified AMF stimulated B16-F1 cell migration in a dose-dependent fashion and bound directly in a protein-protein-binding assay to the AMF receptor, a cell surface glycoprotein of Mr 78,000 [glycoprotein (gp) 78]. The involvement of gp78 in AMF-stimulated function was demonstrated by motility assays. These results suggest that AMF is the natural ligand for the gp78-AMF receptor.

Molecular cloning and chromosomal mapping of a human galactoside-binding protein

A human galactoside-binding protein with an Mr of 31,000 was cloned from the human HT-1080 fibrosarcoma complementary DNA library. A partial complementary DNA clone containing the complete coding region was characterized and the deduced sequence encodes a polypeptide of 242 amino acids with the characteristics of a carbohydrate-binding protein. The gene coding for the human galactoside-binding protein was mapped to the chromosomal band 1p13. The deduced amino acid sequence of the human galactoside-binding protein revealed 95 residues at the amino terminus, homologous to the predicted amino acid sequence of the second exon of the human L-myc gene.

Evidence for the role of 34-kDa galactoside-binding lectin in transformation and metastasis

The endogenous Mr 34,000 galactoside-binding lectin (L-34) is found at elevated levels in a wide variety of neoplastic cells and correlative evidence suggests that it is involved in tumor metastasis in vivo and in transformation in vitro. We demonstrate here that introduction of recombinant L-34 into tumorigenic, weakly metastatic UV-2237-cl-15 fibrosarcoma cells results in an increased incidence of experimental lung metastases in syngeneic and nude mice. Transfection of normal BALB/c-A31 cloned fibroblasts with functional L-34 results in acquisition of anchorage-independent growth and in morphological transformation in vitro but not in tumorigenicity in vivo. These results provide direct evidence that the cellular expression of L-34 is associated with some aspects of transformation and with metastasis, but not with tumorigenicity per se.