Hormonal Injustice: Environmental Toxicants as Drivers of Endocrine Health Disparities

The toll of multiple endocrine disorders has increased substantially in recent decades, and marginalized populations bear a disproportionate burden of disease. Because of the significant individual and societal impact of these conditions, it is essential to identify and address all modifiable risk factors contributing to these disparities. Abundant evidence now links endocrine dysfunction with exposure to endocrine-disrupting chemicals (EDCs), with greater exposures to multiple EDCs occurring among vulnerable groups, such as racial/ethnic minorities, those with low incomes, and others with high endocrine disease burdens. Identifying and eliminating EDC exposures is an essential step in achieving endocrine health equity.

Arsenic metabolism, diabetes prevalence, and insulin resistance among Mexican Americans: A mendelian randomization approach

Background

Differences in arsenic metabolism capacity may influence risk for type 2 diabetes, but the mechanistic drivers are unclear. We evaluated the associations between arsenic metabolism with overall diabetes prevalence and with static and dynamic measures of insulin resistance among Mexican Americans living in Starr County, Texas.

Methods

We utilized data from cross-sectional studies conducted in Starr County, Texas, from 2010-2014. A Mendelian randomization approach was utilized to evaluate the associations between arsenic metabolism and type 2 diabetes prevalence using the intronic variant in the arsenic methylating gene, rs9527, as the instrumental variable for arsenic metabolism. To further assess mechanisms for diabetes pathogenesis, proportions of the urinary arsenic metabolites were employed to assess the association between arsenic metabolism and insulin resistance among participants without diabetes. Urinary biomarkers of arsenic metabolites were modeled as individual proportions of the total. Arsenic metabolism was evaluated both with a static outcome of insulin resistance, homeostatic measure of assessment (HOMA-IR), and a dynamic measure of insulin sensitivity, Matsuda Index.

Results

Among 475 Mexican American participants from Starr County, higher metabolism capacity for arsenic is associated with higher diabetes prevalence driven by worse insulin resistance. Presence of the minor T allele of rs9527 is independently associated with an increase in the proportion of monomethylated arsenic (MMA%) and is associated with an odds ratio of 0.50 (95% CI: 0.24, 0.90) for type 2 diabetes. This association was conserved after potential covariate adjustment. Furthermore, among participants without type 2 diabetes, the highest quartile of MMA% was associated with 22% (95% CI: -33.5%, -9.07%) lower HOMA-IR and 56% (95% CI: 28.3%, 91.3%) higher Matsuda Index for insulin sensitivity.

Conclusions

Arsenic metabolism capacity, indicated by a lower proportion of monomethylated arsenic, is associated with increased diabetes prevalence driven by an insulin resistant phenotype among Mexican Americans living in Starr County, Texas.

Transportation-related Environmental Mixtures and Diabetes Prevalence and Control in Urban/Metropolitan Counties in the United States

Diabetes rates in the United States are staggering and climbing. Importantly, traditional risk factors fail to completely account for the magnitude of the diabetes epidemic. Environmental exposures, including urban and metropolitan transportation quality, are implicated as contributors to disease. Using data from the county-level Environmental Quality Index (EQI) developed for the United States, we analyzed associations between transportation and air quality environmental metrics with overall diabetes prevalence and control within urban/metropolitan counties in the United States from 2006 to 2012. Additionally, we examined effect modification by race/ethnicity through stratification based on the county-level proportion of minority residents. Last, we applied mixture methods to evaluate the effect of simultaneous poor transportation factors and worse air quality on the same outcomes. We found that increased county-level particulate matter air pollution and nitrogen dioxide along with reduced public transportation usage and lower walkability were all associated with increased diabetes prevalence. The minority proportion of the population influences some of these relationships as some of the effects of air pollution and the transportation-related environment are worse among counties with more minority residents. Furthermore, the transportation and air quality mixtures were found to be associated with increased diabetes prevalence and reduced diabetes control. These data further support the burgeoning evidence that poor environments amplify diabetes risk. Future cohort studies should explore the utility of environmental policies and urban planning as tools for improving metabolic health.

Metalloproteinase-9 in the ocular surface of patients with implanted Boston type 1 keratoprosthesis

PURPOSE

To characterize the presence of ocular surface inflammation, using matrix metalloproteinase 9 (MMP-9) as a marker, in the ocular surface of eyes with implanted Boston Keratoprosthesis type 1 (KPro).

METHODS

Patients with implanted KPro at a single tertiary center were recruited to assess ocular inflammation. MMP-9 was measured using InflammaDry^® test in both eyes of each patient. The non-KPro eye served as control. Rate of positivity of MMP-9 was compared between groups. Possible associations between ocular surface inflammation and the development of postoperative complications were evaluated using univariate statistical analysis.

RESULTS

Fifty eyes from 25 patients were included. The mean age was 50 years old. Non-inflammatory indications for KPro were predominant among patients. Eighty eight percent of KPro eyes had a positive test for MMP-9 while only 25% of control eyes were positive (p<001). The most common complications were retroprosthetic membrane, epithelial defects, and sterile corneal melt. The presence of a strong positive result was associated to a higher frequency of complications (80% of eyes) compared to a faint positive test (54%) and a negative test (33%).

CONCLUSION

The KPro device appears to increase MMP-9 levels in the ocular surface. High MMP-9 levels may be associated with higher risk of complications. MMP-9 testing can be useful to assess subclinical ocular surface inflammation with a potential role in the postoperative care of KPro patients.

Relationships Between Urinary Metals and Diabetes Traits Among Mexican Americans in Starr County, Texas, USA

Hispanics/Latinos have higher rates of type 2 diabetes (T2D), and the origins of these disparities are poorly understood. Environmental endocrine-disrupting chemicals (EDCs), including some metals and metalloids, are implicated as diabetes risk factors. Data indicate that Hispanics/Latinos may be disproportionately exposed to EDCs, yet they remain understudied with respect to environmental exposures and diabetes. The objective of this study is to determine how metal exposures contribute to T2D progression by evaluating the associations between 8 urinary metals and measures of glycemic status in 414 normoglycemic or prediabetic adults living in Starr County, Texas, a Hispanic/Latino community with high rates of diabetes and diabetes-associated mortality. We used multivariable linear regression to quantify the differences in homeostatic model assessments for pancreatic β-cell function, insulin resistance, and insulin sensitivity (HOMA-β, HOMA-IR, HOMA-S, respectively), plasma insulin, plasma glucose, and hemoglobin A1c (HbA1c) associated with increasing urinary metal concentrations. Quantile-based g-computation was utilized to assess mixture effects. After multivariable adjustment, urinary arsenic and molybdenum were associated with lower HOMA-β, HOMA-IR, and plasma insulin levels and higher HOMA-S. Additionally, higher urinary copper levels were associated with a reduced HOMA-β. Lastly, a higher concentration of the 8 metal mixtures was associated with lower HOMA-β, HOMA-IR, and plasma insulin levels as well as higher HOMA-S. Our data indicate that arsenic, molybdenum, copper, and this metal mixture are associated with alterations in measures of glucose homeostasis among non-diabetics in Starr County. This study is one of the first to comprehensively evaluate associations of urinary metals with glycemic measures in a high-risk Mexican American population.

Abstract P1-12-05: A qualitative exploration of self-developed and peer-recommended techniques used by women with breast cancer to improve sexual functioning during and after treatment

Background: Coping with sexual dysfunction during and after breast cancer treatment is a persistent challenge for many women, even if clinicians offer standard sexual rehabilitative therapies (e.g. lubricants, counseling). This study sought to explore how women with breast cancer supplement clinician recommendations with self-developed and peer-recommended techniques for improving sexual function, what those techniques are, and how well they work.

Methods: We conducted a cross-sectional, online survey of 501 adult women with stage I-IV breast cancer who were members of the Breastcancer.org community. Open-ended survey items asked women to describe any techniques used to improve sexual function during and after breast cancer treatment beyond those recommended by clinicians. Closed-ended items asked women to assess the source and perceived efficacy of their techniques. We used qualitative content analysis to extract themes that described women's techniques and calculated frequencies in StataMP 15 to quantify sources and efficacy levels.

Results: Participants were, on average, age 53 (range 30-79) and 10 years from diagnosis. Most were partnered (90%), heterosexual (96%), with stage I/II disease (73%). 174/501 (35%) women reported using a sexual self-management technique they developed themselves or that was recommended by someone other than a clinician. Emergent themes in techniques included: 1) pain reduction: trial-and-error to find an effective lubricant or moisturizer (e.g. coconut oil), changing sex positions, choosing oral sex over intercourse 2) intimacy enhancement: open partner communication, planning sex 3) arousal enhancement: masturbation, erotica, vibrator use 4) emotional coping: adopting an attitude of persistence vs. acceptance of loss of sex life, encouraging partners to use sexual surrogates. 77 women developed the technique themselves, 54 with partners, 37 heard about it from survivors, 36 read about it online. 45% of women rated their techniques as moderately or more effective when used in addition to or instead of standard therapies offered by clinicians.

Conclusion: In a survey of an Internet-based community of women treated for breast cancer, women reported a variety of successful techniques for increasing intimacy and arousal, reducing vaginal pain, and coping emotionally with changes in sexual life after breast cancer. More women reported developing these techniques on their own or with partners vs. learning them from others. Given that standard therapies are often insufficient to manage sexual dysfunction during and after breast cancer treatment, clinicians should address sexual function during follow-up care and encourage women's safe experimentation with techniques for improving sexual function. Clinicians can refer patients to platforms like Breastcancer.org for peer-to-peer support and information exchange. Existing self-developed and peer-recommended techniques should be evaluated for safety, quality, and generalizability. Future research can then assess the effectiveness of particularly novel techniques as a complement to standard, clinician-developed therapies for the broader population of women with breast cancer experiencing sexual dysfunction.

Citation Format: von Hippel CD, Rosenberg SM, Jenkins MB, Weiss MC, Partridge AH. A qualitative exploration of self-developed and peer-recommended techniques used by women with breast cancer to improve sexual functioning during and after treatment [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-05.

Origin and phylogenetic relationships of [4Fe-4S]-containing O2 sensors of bacteria

The advent of environmental O₂ about 2.5 billion years ago forced microbes to metabolically adapt and to develop mechanisms for O₂ sensing. Sensing of O₂ by [4Fe-4S]²⁺ to [2Fe-2S]²⁺ cluster conversion represents an ancient mechanism that is used by FNR_Ec (Escherichia coli), FNR_Bs (Bacillus subtilis), NreB_Sa (Staphylococcus aureus) and WhiB3_Mt (Mycobacterium tuberculosis). The phylogenetic relationship of these sensors was investigated. FNR_Ec homologues are restricted to the proteobacteria and a few representatives from other phyla. Homologues of FNR_Bs and NreB_Sa are located within the bacilli, of WhiB3 within the actinobacteria. Archaea contain no homologues. The data reveal no similarity between the FNR_Ec , FNR_Bs , NreB_Sa and WhiB3 sensor families on the sequence and structural levels. These O₂ sensor families arose independently in phyla that were already present at the time O₂ appeared, their members were subsequently distributed by lateral gene transfer. The chemistry of [4Fe-4S] and [2Fe-2S] cluster formation and interconversion appears to be shared by the sensor protein families. The type of signal output is, however, family specific. The homologues of FNR_Ec and NreB_Sa vary with regard to the number of Cys residues that coordinate the cluster. It is suggested that the variants derive from lateral gene transfer and gained other functions.

Minor ailment consultations: a mismatch of perceptions

Focal points

Pharmacists' perceptions and experiences of pharmacy protocols: a step in the right direction?

A postal questionnaire to 300 pharmacists in Lancashire, investigating community pharmacists' perceptions of the usefulness of medicine sales protocols, was completed by 138 (46 per cent). Almost all of the respondents (96 per cent) stated that they used protocols in their place of work. Of the 95 respondents who indicated the frequency with which customers were unwilling to answer questions, 94 per cent stated this frequency was at least one in every 10 customers. Examples of customers who were sometimes unwilling to answer questions included some who had used the medicine previously, some with a condition of a sensitive nature and some purchasing on behalf of a third party. Although the majority of respondents were positive towards the impact and future development of protocols, 37 felt protocols required modification and greater flexibility. Comments suggested that protocols could both enhance the professional image of pharmacy and be professionally restrictive. Protocols should be developed which reflect both the patient, as well as the professional, perspective.

Site-directed mutagenesis of the nitrogenase MoFe protein of Azotobacter vinelandii

A strategy has been formulated for the site-directed mutagenesis of the Azotobacter vinelandii nifDK genes. These genes encode the alpha and beta subunits of the MoFe protein of nitrogenase, respectively. Six mutant strains, which produce MoFe proteins altered in their alpha subunit by known single amino acid substitutions, have been produced. Three of these transversion mutations involve cysteine-to-serine changes (at residues 154, 183, and 275), two involve glutamine-to-glutamic acid changes (at residues 151 and 191), and one involves an aspartic acid-to-glutamic acid change (at residue 161). All three possible phenotypic responses are observed within this group- i.e., normal, slow, and no growth in the absence of a fixed-nitrogen source. Two-dimensional gel electrophoresis indicates that all mutants accumulate normal levels of the subunits of both nitrogenase component proteins. Whole-cell and crude-extract acetylene-reduction activities indicate substantial levels of Fe protein activity in all strains. In contrast, MoFe protein activities do not parallel the diazotrophic growth capability for all strains. Two strains appear to exhibit altered substrate discrimination. Such analyses should aid in the identification of metallocluster-binding sites and subunit-subunit interaction domains of the MoFe protein and also provide insight into the mechanistic roles of the various prosthetic groups in catalysis.

Perceptions of patient expectation for an antibiotic: a comparison of walk-in centre nurses and GPs

BACKGROUND

Patient expectation for a prescription is a recognized influence on GPs' prescribing, particularly in relation to the prescribing of antibiotics. Nurses are now able to supply antibiotics under a Patient Group Direction (PGD) in NHS walk-in centres and may experience similar pressures in this new role.

OBJECTIVES

Our aim was to compare walk-in centre nurses' and GPs' perceptions of the influence of patient expectation on their supply of an antibiotic to patients with an acute respiratory tract infection presenting with a sore throat or cough.

METHODS

Between June and December 2001, all patients presenting with a sore throat or cough at six walk-in centres and six nearby general practices were eligible to participate in the study. After the health professional-patient consultation, the health professional and the patient each completed a questionnaire.

RESULTS

There were 472 health professional (181 GPs and 291 walk-in centres) and 160 (34%, 160 out of 472) patient questionnaires returned. GPs were more likely to report that the patient expected an antibiotic than nurses (72% of 181 versus 13% of 291, P < 0.001). GPs were also less likely to report that an antibiotic was indicated than nurses (88% of 136 versus 97% of 194, P < 0.001). There was a trend for doctors to prescribe more frequently than nurses, in 74% of 180 patients versus 66% of 291 patients (P = 0.06). GPs were likely to report that the patient expected an antibiotic when the patient reported wanting a prescription (60% of 68, P = 0.05) and to report that the patient expected an antibiotic if the patient thought an antibiotic would be beneficial (62% of 68, P = 0.001). There was a much weaker relationship between nurse perceptions of patient expectation for an antibiotic and, either patient desire for a prescription or the patient's affirmative belief that an antibiotic would be beneficial.

CONCLUSIONS

Nurses may be compensating for a lack of security in their new role as antibiotic suppliers by not acknowledging the influence of patient expectation on their decision making. The acknowledgement of the influence of patient expectation might be beneficial to nurses' development as suppliers of medicines by giving them greater understanding of the consultation process and in the need to discuss patient expectations explicitly in the consultation.

GPs' attitudes to minor ailments

BACKGROUND

It is generally considered that a significant proportion of 'inappropriate' demand for GP services is generated by consultations for minor ailments. How GPs manage minor ailments is likely to affect how patients perceive and handle similar illnesses in the future. Whilst this potentially has significant implications for general practice workload, research investigating GP' attitudes towards minor ailments and their management is sparse.

OBJECTIVE

Our aim was to describe GP' experiences and perceptions of minor ailment consultations and their attitudes towards minor ailment management.

METHODS

A questionnaire survey was conducted in 1999, derived from a series of 20 qualitative interviews with practising GPs. The survey was sent to one GP randomly selected from each practice (n = 759) in eight English health authorities. Attitudinal statements were analysed using factor analysis.

RESULTS

Four hundred and fourteen GPs (54.5%) completed and returned the questionnaire. Respondents were consulted regularly about minor illness or symptoms, with almost all (95.6%) having experienced a minor ailment consultation in the previous week. Factor analysis suggested four issues to be of importance in determining GP' attitudes to minor ailment management. These were attitudes towards pharmacists, attitudes towards patient empowerment, frustration with minor ailment consultations and attitudes towards caution/risk.

CONCLUSION

Although GPs are clearly frustrated by the level of minor ailment consultations, this study suggests that there may be complex factors which influence their attitudes. For the optimal management of minor ailments, inter-professional relationships potentially are of great importance. With increasing patient demand, it is essential that finite health care resources are accessible, appropriate and used in an optimal way.

Expression of HNF4alpha isoforms in mouse liver development is regulated by sequential promoter usage and constitutive 3' end splicing

Hepatocyte nuclear factor 4alpha (HNF4alpha) is essential for the establishment and maintenance of liver-specific gene expression. The HNF4alpha gene codes for several isoforms whose developmental and physiological relevance has not yet been explored. HNF4alpha1 and HNF4alpha7 originate from different promoters, while alternative splicing in 3' leads to HNF4alpha2 and HNF4alpha8, respectively. HNF4alpha7/alpha8 were abundantly expressed in embryonic liver and fetal-like hepatoma cells. HNF4alpha1/alpha2 transcripts were up-regulated at birth and represented the only isoforms in adult-like hepatoma cells. In line with its expression profile, HNF4alpha7 activated more avidly than HNF4alpha1 reporter plasmids for genes that are expressed early. The expression patterns of both isoforms together with the differences observed in their transcriptional activities provide elements accounting for fine-tuning of the activity of HNF4alpha. The sequential expression of HNF4alpha7/alpha8 and HNF4alpha1/alpha2 during mouse liver development is the only modification in liver-enriched transcription factors thus far recorded, which parallels the transition from the fetal to the adult hepatic phenotype.

Hormone response of rodent phenylalanine hydroxylase requires HNF1 and the glucocorticoid receptor

Expression of the rodent phenylalanine hydroxylase (PAH) gene is dependent upon hormones. Induction by glucocorticoids and cAMP occurs slowly and maximal stimulation is obtained by a synergistic effect of the two compounds. Hormone responsiveness is conferred by the tissue-specific HSIII enhancer and involves (i) protein kinase A mediating the cAMP response, even though a consensus sequence for binding of the cAMP response element binding protein is not present; (ii) other serine/threonine kinases as deduced from inhibitor studies; (iii) glucocorticoid receptor protein bound to glucocorticoid response element half sites; and (iv) binding of the liver-enriched transcription factor hepatocyte nuclear factor 1 (HNF1) to sites in the enhancer. Glucocorticoid receptor and HNF1, bound to their cognate sites, cooperatively increase the glucocorticoid response of the PAH gene, this response being synergistically enhanced by cAMP after long-term treatment.

An enhancer element 6 kb upstream of the mouse HNF4alpha1 promoter is activated by glucocorticoids and liver-enriched transcription factors

We have characterized a 700 bp enhancer element around -6 kb relative to the HNF4alpha1 transcription start. This element increases activity and confers glucocorticoid induction to a heterologous as well as the homologous promoters in differentiated hepatoma cells and is transactivated by HNF4alpha1, HNF4alpha7, HNF1alpha and HNF1beta in dedifferentiated hepatoma cells. A 240 bp sub-region conserves basal and hormone-induced enhancer activity. It contains HNF1, HNF4, HNF3 and C/EBP binding sites as shown by DNase I footprinting and electrophoretic mobility shift assays using nuclear extracts and/or recombinant HNF1alpha and HNF4alpha1. Mutation analyses showed that the HNF1 site is essential for HNF1alpha transactivation and is required for full basal enhancer activity, as is the C/EBP site. Glucocorticoid response element consensus sites which overlap the C/EBP, HNF4 and HNF3 sites are crucial for optimal hormonal induction. We present a model that accounts for weak expression of HNF4alpha1 in the embryonic liver and strong expression in the newborn/adult liver via the binding sites identified in the enhancer.

Conserved as well as divergent regulatory elements account for expression of the human and rodent phenylalanine hydroxylase genes

We have uncovered a fundamental difference in the regulation of the rodent and the human phenylalanine hydroxylase (PAH) genes: expression of human PAH is independent of glucocorticoids and/or cAMP in contrast to the mouse gene which is not only highly inducible but dependent upon hormones for expression. Nevertheless, the two genes do exhibit similarities: DNaseI hypersensitive sites are identically located in the regulatory regions, and the sequences around these sites are partially conserved and associated with regulatory elements sharing similar function. In transient transfections, the human proximal promoter is tissue-specific and presents significant activity compared to the extremely low and ubiquitous activity of the mouse promoter. DNA fragments corresponding to the two upstream hypersensitive sites of both genes have enhancer activity that depends upon the liver-enriched transcription factor binding sites for hepatocyte nuclear factor (HNF) 1 and/or CCAAT/enhancer binding protein (C/EBP). While expression of the rodent gene relies upon two modules in the HSIII enhancer, one activated by HNF1 and C/EBP and the other required for the hormone response, the human equivalent has conserved only the liver-specific transcription factor binding module. Even though the more proximal enhancer is not necessary for full reporter gene activity in transient transfection assays in Pah-expressing hepatoma cells, this enhancer could be required in both species for activation during development.

GP survey response rate: a miscellany of influencing factors

BACKGROUND

GP response to surveys is acknowledged to vary widely. The minimization of non-response bias and the generalizability of findings are fundamental research issues.

OBJECTIVE

The aim of this study was to identify the factors that had influenced GPs' decisions to complete a questionnaire.

METHODS

A short questionnaire eliciting GPs' views on minor ailment consultations was sent to 759 GPs from eight English health authorities. The response rate was 54.5%. Factors perceived by respondents to have influenced their decision to complete this questionnaire were also assessed. Subsequently, a feedback summary, together with a short evaluation form, was sent to those GPs requesting it.

RESULTS

The response from GPs located in the London area was significantly lower than that from those elsewhere. Respondents identified questionnaire length and the originating institution as the two major factors influencing their decision to return the survey. A single mailing of the evaluation form yielded a response rate of >60% predominantly positive comments.

CONCLUSION

Many factors influence a GP's decision to complete a survey. The effect of location has, to date, largely been ignored. Furthermore, this study suggested feedback to be an important issue. Within health services research, all possible factors need to be considered to maximize response, reduce non-response bias and ultimately facilitate the dissemination of findings.

Muscle-regulated expression and determinants for neuromuscular junctional localization of the mouse RIalpha regulatory subunit of cAMP-dependent protein kinase

In skeletal muscle, transcription of the gene encoding the mouse type Ialpha (RIalpha) subunit of the cAMP-dependent protein kinase is initiated from the alternative noncoding first exons 1a and 1b. Here, we report that activity of the promoter upstream of exon 1a (Pa) depends on two adjacent E boxes (E1 and E2) in NIH 3T3-transfected fibroblasts as well as in intact muscle. Both basal activity and MyoD transactivation of the Pa promoter require binding of the upstream stimulating factors (USF) to E1. E2 binds either an unknown protein in a USF/E1 complex-dependent manner or MyoD. Both E2-bound proteins seem to function as repressors, but with different strengths, of the USF transactivation potential. Previous work has shown localization of the RIalpha protein at the neuromuscular junction. Using DNA injection into muscle of plasmids encoding segments of RIalpha or RIIalpha fused to green fluorescent protein, we demonstrate that anchoring at the neuromuscular junction is specific to RIalpha subunits and requires the amino-terminal residues 1-81. Mutagenesis of Phe-54 to Ala in the full-length RIalpha-green fluorescent protein template abolishes localization, indicating that dimerization of RIalpha is essential for anchoring. Moreover, two other hydrophobic residues, Val-22 and Ile-27, are crucial for localization of RIalpha at the neuromuscular junction. These amino acids are involved in the interaction of the Caenorhabditis elegans type Ialpha homologue R(CE) with AKAP(CE) and for in vitro binding of RIalpha to dual A-kinase anchoring protein 1. We also show enrichment of dual A-kinase anchoring protein 1 at the neuromuscular junction, suggesting that it could be responsible for RIalpha tethering at this site.

Type I protein kinase a is localized to interphase microtubules and strongly associated with the mitotic spindle

We show here that type I protein kinase A is localized to microtubules during the entire cell cycle in epithelial (hepatoma, cervical carcinoma) and nonepithelial (myoblast) cell lines. The association of the type Ialpha regulatory subunit is very strong in all phases of mitosis, from prophase to cytokinesis. In interphase, the association appears weaker, reflecting perhaps a more dynamic molecular interaction. This regulatory subunit appears to recruit catalytic subunits as the latter are also associated with microtubules. BW1J hepatoma cells, stably transfected with either wild-type or mutant Ialpha regulatory subunit, are enriched in aberrant mitoses with multipolar spindles and in mono- or multinucleated giant cells. This suggests that type I protein kinase A could have a role in centrosome duplication and/or segregation, sister chromatid separation, or cytokinesis.

Inhibition of MMH (Met murine hepatocyte) cell differentiation by TGF(beta) is abrogated by pre-treatment with the heritable differentiation effector FGF1

MMH (Met murine hepatocyte) liver cells derived from transgenic mice expressing a truncated constitutively active form of human c-Met are non-transformed immortalized cell lines. We have previously shown that they harbor: (1) epithelial cells that express the liver-enriched transcription factors HNF4 and HNF1(alpha), and that can be stably induced by FGF1 to express liver functions, and (2) fibroblast-like bi-potential palmate cells that can differentiate into bile duct-like structures in Matrigel cultures, or into epithelial cells competent to express hepatic functions. Low concentrations of TGF(beta) have been found to inhibit growth and differentiation of MMH cells. The factor stabilized the palmate cell phenotype, and it provoked epithelial cells to acquire palmate-like morphological characteristics, in parallel with down-regulation of expression of HNF4 and HNF1(alpha) and activation of Snail transcripts. The effects of TGF(beta) were dominant if it was added with FGF1, but the effects on differentiation were abrogated if cells had been pre-treated with FGF1. This work identifies TGF(beta) as a factor that could be implicated in maintaining bi-potential precursor cells in the liver, FGF1 as one that could over-ride the TGF(beta) effects and Snail as a candidate for mediation of the signal.

British community pharmacists' views of physician-assisted suicide (PAS)

OBJECTIVES

To explore British community pharmacists' views on PAS, including professional responsibility, personal beliefs, changes in law and ethical guidance.

DESIGN

Postal questionnaire.

SETTING

Great Britain.

SUBJECTS

A random sample of 320 registered full-time community pharmacists.

RESULTS

The survey yielded a response rate of 56%. The results showed that 70% of pharmacists agreed that it was a patient's right to choose to die, with 57% and 45% agreeing that it was the patient's right to involve his/her doctor in the process and to use prescription medicines, respectively. Forty-nine per cent said that they would knowingly dispense a prescription for use in PAS were it to be legalized and 54% believed it correct to refuse to dispense such a prescription. Although 53% believed it to be their right to know when they were being involved in PAS, 28% did not. Most pharmacists (90%) said that they would wish to see the inclusion of a practice protocol for PAS in the code of ethics of the Royal Pharmaceutical Society of Great Britain (CE-RPSGB) in the event of a change in the law on PAS. In addition, 89% would wish to see PAS included in the Conscience Clause of the CE-RPSGB. Males were found to be significantly less likely to favour PAS than females (p < 0.05), as were those declaring an ethnic/religious background of consideration when dealing with ethical issues in practice compared with their counterparts (p < 0.00005).

CONCLUSION

Pharmacists view their professional responsibility in PAS to be more obligatory than a physician's, in having to provide the means for PAS. It is worrying that a proportion of the respondents prefer to remain in ignorance of the true purpose of a prescription for PAS; a finding at odds with current developments within the pharmaceutical profession. A practice protocol for PAS and an extension of the conscience clause should be considered in the event of PAS becoming legal. Such measures would allow the efficient provision of the pharmaceutical service whilst at the same respecting the personal beliefs of those who object to cooperating in the ending of a life.

Alternative 5'-exons of the mouse cAMP-dependent protein kinase subunit RIalpha gene are conserved and expressed in both a ubiquitous and tissue-restricted fashion

The activity of cAMP-dependent protein kinase is controlled by its regulatory subunits. Mouse RIalpha regulatory subunit expression is initiated from five different non-coding 5'-regions (exons 1a, 1b, 1c, 1d and 1e). This organization appears to be conserved among species. All mouse tissues accumulate exon 1a and 1b transcripts and most contain more 1b than 1a, except brain, heart and oesophagus. Exon 1d and 1e transcripts are found in several tissues, while exon 1c is testis-specific. All five transcripts are in RIalpha-rich tissues: gonads and adrenal glands.

Identification of a bipotential precursor cell in hepatic cell lines derived from transgenic mice expressing cyto-Met in the liver

Met murine hepatocyte (MMH) lines were established from livers of transgenic mice expressing constitutively active human Met. These lines harbor two cell types: epithelial cells resembling the parental populations and flattened cells with multiple projections and a dispersed growth habit that are designated palmate. Epithelial cells express the liver-enriched transcription factors HNF4 and HNF1alpha, and proteins associated with epithelial cell differentiation. Treatments that modulate their differentiation state, including acidic FGF, induce hepatic functions. Palmate cells show none of these properties. However, they can differentiate along the hepatic cell lineage, giving rise to: (a) epithelial cells that express hepatic transcription factors and are competent to express hepatic functions; (b) bile duct-like structures in three-dimensional Matrigel cultures. Derivation of epithelial from palmate cells is confirmed by characterization of the progeny of individually fished cells. Furthermore, karyotype analysis confirms the direction of the phenotypic transition: palmate cells are diploid and the epithelial cells are hypotetraploid. The clonal isolation of the palmate cell, an immortalized nontransformed bipotential cell that does not yet express the liver-enriched transcription factors and is a precursor of the epithelial-hepatocyte in MMH lines, provides a new tool for the study of mechanisms controlling liver development.

Phenotypic effects of the forced expression of HNF4 and HNF1alpha are conditioned by properties of the recipient cell

Tagged versions of HNF4 or HNF1alpha cDNAs in expression vectors have been introduced by transient and stable transfection into three cell lines of hepatic origin that all fail to express these two liver-enriched transcription factors and hepatic functions. C2 and H5 cells are dedifferentiated rat hepatoma variants and WIF12-E cells are human fibroblast-rat hepatoma hybrids with a reduced complement of human chromosomes. Transfectants were analyzed for the expression state of the endogenous genes coding for these transcription factors and for hepatic functions. Each cell line showed a different response to the forced expression of the transcription factors. In C2 cells, no measurable effect was observed, either upon transitory or stable expression. H5 cells reexpressed the endogenous HNF4 gene only upon transient HNF1alpha transfection, and the endogenous HNF1alpha gene only in stable HNF4 transfectants. WIF12-E cells responded to the forced transient or stable expression of either HNF1alpha or HNF4 by cross-activation of the corresponding endogenous gene. In addition, the stable transfectants reexpress HNF3alpha and C/EBPalpha, as well as all of the hepatic functions examined. Hybrid cells similar to WIF12-E had previously been observed to show pleiotropic reexpression of the hepatic phenotype in parallel with loss of human chromosome 2. For the stable WIF12-E transfectants, it was verified that reexpression of the hepatic phenotype was not due to loss of human chromosome 2. The demonstration of reciprocal cross-regulation between HNF4 and HNF1alpha in transient as well as stable transfectants implies that direct effects are involved.

Differences in fatigue by treatment methods in women with breast cancer

PURPOSE/OBJECTIVES

To investigate the differences between various cancer therapies (radiation, hormonal, chemotherapy, and their combinations) and the specific dimensions of fatigue (affective meaning, behavioral/severity, cognitive/mood, and sensory).

DESIGN

Descriptive, cross-sectional, mailed survey design.

SAMPLE AND SETTING

Data were collected from women who were breast cancer survivors and members of a nonprofit educational organization in the North-east. Criteria for this study included no self-reported disease recurrence, and treatment was within 18 months prior to the mailed survey (N = 322). The typical participant was middle-aged (mean = 52.2; SD = 10.3), Caucasian (93%), postmenopausal (55%), and diagnosed with cancer 2.42 (SD = 2.6) years prior to the study.

METHODS

Secondary data analysis from a study using the Piper Fatigue Scale.

VARIABLES

Level of fatigue.

FINDINGS

Significant differences were found by treatment in total fatigue scores (p < 0.03) and cognitive/mood scores (p < 0.05). Women who received combination therapy had the highest fatigue scores (mean = 4.8; SD = 2.0); those who received only radiation therapy had the lowest fatigue scores (mean = 2.7; SD = 2.0).

CONCLUSIONS

Fatigue in breast cancer survivors varies by type of cancer therapy. Future studies are needed to investigate the relationships between fatigue and hormonal therapy, and they need to be designed to examine changes over time.

IMPLICATIONS FOR NURSING PRACTICE

Study findings advance knowledge about fatigue in women with breast cancer and aid nurses in providing anticipatory guidance for women undergoing different treatment regimens.

The revised Piper Fatigue Scale: psychometric evaluation in women with breast cancer

PURPOSE/OBJECTIVES

To confirm the multidimensionality of the Piper Fatigue Scale (PFS) and to reduce the total number of PFS items without compromising reliability and validity estimates.

DESIGN

Methodologic, part of a larger, cross-sectional, mailed survey design study.

SETTING

Urban and suburban area in the northeast United States.

SAMPLE

As part of the larger study, 2,250 surveys were distributed to women survivors of breast cancer who were on a mailing list for the educational organization Living Beyond Breast Cancer, 715 surveys (32%) were returned. Of these, 382 women met this methodologic study's criteria for having completed each of the 40 items on the PFS. The average respondent was 50 years old, postmenopausal, and treated with combination cancer therapy.

METHODS

Principal axes factor analysis with oblique rotation.

MAIN RESEARCH VARIABLES

Fatigue factors/subscales.

FINDINGS

Five factors/subscales were identified initially. Because the fifth factor contained only two items (ability to bathe/wash and ability to dress), these items and the associated factor/subscale were dropped from the final solution. An additional nine items, not loading on any factor (> 0.40), also were dropped. The remaining items and factors/subscales were reviewed to ensure that the criteria were met: a pattern of inter-item correlations between 0.30-0.70; a minimum number of five or more items/subscale; standardized alpha for the subscales and total scale of at least 0.89; and absence of gender-specific items.

CONCLUSIONS

The revised version of the PFS consists of 22 items and four subscales: behavioral/severity (6 items), affective meaning (5 items), sensory (5 items) and cognitive/mood (6 items). Standardized alpha for the entire scale (n = 22 items) is 0.97, indicating that some redundancy still may exist among the items. Additional revisions await further testing.

IMPLICATIONS FOR NURSING PRACTICE

As fatigue is acknowledged to be the most frequent symptom experienced by patients with cancer, accurate measurement and assessment is essential to advance not only the science of fatigue but, most importantly, to evaluate the efficacy of intervention strategies on patient and family outcomes.

Hepatocyte nuclear factor 4 provokes expression of epithelial marker genes, acting as a morphogen in dedifferentiated hepatoma cells

We have recently shown that stable expression of an epitope-tagged cDNA of the hepatocyte- enriched transcription factor, hepatocyte nuclear factor (HNF)4, in dedifferentiated rat hepatoma H5 cells is sufficient to provoke reexpression of a set of hepatocyte marker genes. Here, we demonstrate that the effects of HNF4 expression extend to the reestablishment of differentiated epithelial cell morphology and simple epithelial polarity. The acquisition of epithelial morphology occurs in two steps. First, expression of HNF4 results in reexpression of cytokeratin proteins and partial reestablishment of E-cadherin production. Only the transfectants are competent to respond to the synthetic glucocorticoid dexamethasone, which induces the second step of morphogenesis, including formation of the junctional complex and expression of a polarized cell phenotype. Cell fusion experiments revealed that the transfectant cells, which show only partial restoration of E-cadherin expression, produce an extinguisher that is capable of acting in trans to downregulate the E-cadherin gene of well-differentiated hepatoma cells. Bypass of this repression by stable expression of E-cadherin in H5 cells is sufficient to establish some epithelial cell characteristics, implying that the morphogenic potential of HNF4 in hepatic cells acts via activation of the E-cadherin gene. Thus, HNF4 seems to integrate the genetic programs of liver-specific gene expression and epithelial morphogenesis.

Liver-enriched transcription factors uncoupled from expression of hepatic functions in hepatoma cell lines

Among the liver-enriched transcription factors identified to date, only expression of hepatocyte nuclear factor 4 (HNF4) and hepatocyte nuclear factor 1 (HNF1) is in strict correlation with hepatic differentiation in cultured rat hepatoma cells. Indeed, differentiated hepatoma cells that stably express an extensive set of adult hepatic functions express liver-enriched transcription factors, while dedifferentiated cells that have lost expression of all these hepatic functions no longer express HNF4 and HNF1. We describe a new heritable phenotype, designated as uncoupled, in which there is a spontaneous dissociation between the expression of these transcription factors and that of the hepatic functions. Cells presenting this phenotype, isolated from differentiated hepatoma cells, cease to accumulate all transcripts coding for hepatic functions but nevertheless maintain expression of HNF4 and HNF1. Transitory transfection experiments indicate that these two factors present in these cells have transcriptional activity similar to that of differentiated hepatoma cells. Characterization of the appropriate intertypic cell hybrids demonstrates that this new phenotype is recessive to the dedifferentiated state and fails to be complemented by differentiated cells. These results indicate the existence of mechanisms that inhibit transcription of genes coding for hepatocyte functions in spite of the presence of functional HNF4 and HNF1. Cells of the uncoupled phenotype present certain properties of oval cells described for pathological states of the liver.

Hepatocyte nuclear factor 1alpha gene inactivation impairs chromatin remodeling and demethylation of the phenylalanine hydroxylase gene

Hepatocyte nuclear factor 1 alpha (HNF1alpha) is a homeoprotein that is expressed in the liver, kidney, pancreas, and digestive tract. Its inactivation in mouse resulted in decreased transcription of known target genes such as albumin and alpha1-antitrypsin. In contrast, the phenylalanine hydroxylase (PAH) gene was totally silent and unresponsive to normal inducers like glucocorticoids and cyclic AMP in the liver. DNase I and micrococcal nuclease digestion of liver nuclei showed that HNF1alpha inactivation had drastic effects on the chromatin structure of the PAH regulatory regions. Three DNase I-hypersensitive sites (HSSI, HSSII, and HSSIII), typical of the actively transcribed PAH gene, were undetectable in liver from HNF1alpha-deficient animals. Both HSSII and HSSIII elements harbor HNF1 sites, but only the latter has detectable enhancer activity in transient-transfection assays. In addition, the PAH promoter in livers of HNF1alpha-deficient animals was methylated. These results suggest that HNF1alpha could activate transcription through two mechanisms. One implies participation in the recruitment of the general transcription machinery to the promoter, and the second involves the remodeling of chromatin structure and demethylation that would allow transcription factors to interact with their cognate cis-acting elements.

Hepatocyte nuclear factor 4 expression overcomes repression of the hepatic phenotype in dedifferentiated hepatoma cells

The capacity of the liver-enriched transcription factor hepatocyte nuclear factor 4 (HNF4) to direct redifferentiation of dedifferentiated rat hepatoma cells was investigated by stable transfection of epitope-tagged HNF4 cDNA into H5 variant cells. HNF4-producing cells expressed the previously silent HNF1 gene and showed activation of some hepatic functions, including alpha1-antitrypsin, beta-fibrinogen, and transthyretin, but not of the endogenous HNF4 gene. Expression of the other hepatocyte-enriched transcription factors was not modified. Treatment of the HNF4tag-expressing cells with dexamethasone induced expression of the transgene by 10-fold, resulting in enhanced expression of target genes of both glucocorticoid hormones and HNF4. The set of activated hepatic genes was extended by treatment of cells with the demethylating agent 5-azacytidine followed by selection in dexamethasone-containing glucose-free medium. Some of the colonies that developed reexpressed the entire set of hepatic functions tested. Fusion of HNF4tag-producing H5 cells with well-differentiated Fao cells showed that only those hybrids which maintained expression of HNF4tag were protected from complete extinction, including that of the Fao HNF4 gene. Thus, H5 cells must produce an extinguisher of the HNF4 gene. In addition, this result implies that HNF4 itself, or its target HNF1, is a positive regulator of HNF4. In conclusion, HNF4tag expression overcomes repression of the hepatic phenotype of the H5 cell without abolishing its potential to extinguish an active genome. Taken together, these results predict that expression of HNF4 should be sufficient to establish heritable expression of many parameters of the hepatic differentiated state.

Transgenic expression in the liver of truncated Met blocks apoptosis and permits immortalization of hepatocytes

Hepatocyte growth factor induces proliferation, motility and differentiation of epithelial cells through the tyrosine kinase receptor encoded by the MET protooncogene. The cytoplasmic portion of Met (referred to as cyto-Met) is activated but only weakly transforming. In order to determine the effect of activated Met on hepatocytes, we have targeted truncated Met expression to the liver by incorporating the cDNA into a vector carrying the entire human alpha-1-antitrypsin transcriptional unit. Transgenic expression in the liver of truncated human Met, containing the regulatory and the catalytic cytoplasmic domains, renders hepatocytes constitutively resistant to apoptosis and reproducibly permits immortalization. The emerging stable cell lines are not transformed and maintain a highly differentiated phenotype judged by the retention of epithelial cell polarity and the expression of hepatocyte-enriched transcription factors as well as hepatic products.

Pressures on the general practitioner and decisions to prescribe

OBJECTIVES

This study examined the extent to which four broad areas of concern associated with prescribing are perceived by general practitioners (GPs): their sense of burden in providing health care, their views on financial constraints and incentives, the use of a prescription to cope with clinical workload and their perception of demanding patients. A secondary aim was to relate these concerns to actual measures of prescribing behaviour using PACT data.

METHOD

A questionnaire covering the four themes was sent to 386 GPs. Using factor analysis, new measures were constructed to reflect the GPs' perception of the four areas of concern.

RESULTS

A total of 228 GPs (59%) completed the questionnaire. Results indicated a high level of concern among GPs regarding current pressures that could affect prescribing. Only the respondents' concern about the possible adverse effects of financial pressures upon medical decisions was related to prescribing: those concerned about financial pressures prescribed less generically (P < 0.0005), had higher practice costs compared with the Family Health Services Authority average (P = 0.002) and issued more prescriptions overall (P = 0.007).

CONCLUSION

There is a continuing need to monitor and evaluate the effect of recent changes in primary care for their effect upon prescribing behaviour.

Accumulation in fetal muscle and localization to the neuromuscular junction of cAMP-dependent protein kinase A regulatory and catalytic subunits RI alpha and C alpha

Using probes specific for cAMP-dependent protein kinase, we have analyzed by in situ hybridization the patterns of expression of regulatory and catalytic subunits in mouse embryos and in adult muscle. RI alpha transcripts are distributed in muscle fibers exactly as acetylcholinesterase, showing that this RNA is localized at the neuromuscular junction. The transcript levels increase upon denervation of the muscle, but the RNA remains localized, indicating a regulation pattern similar to that of the epsilon subunit of nicotinic acetylcholine receptor. RI alpha transcripts have accumulated in the muscle by day 12 of mouse embryogenesis, and localization is established by day 14, at about the time of formation of junctions. This localization is maintained throughout development and in the adult. Immunocytochemical analysis has demonstrated that RI alpha protein is also localized. In addition, RI alpha recruits C alpha protein to the junction, providing at this site the potential for local responsiveness to cAMP. PKA could be implicated in the establishment and/or maintenance of the unique pattern of gene expression occurring at the junction, or in the modulation of synaptic activity via protein phosphorylation. Embryonic skeletal muscle shows a high level of C alpha transcripts and protein throughout the fiber; the transcripts are already present by day 12 of embryogenesis, and their elevated level is maintained only through fetal life. In the adult, the C alpha hybridization signal of muscle is weak and homogeneous.

The activity of the highly inducible mouse phenylalanine hydroxylase gene promoter is dependent upon a tissue-specific, hormone-inducible enhancer

Expression of the phenylalanine hydroxylase gene in livers and kidneys of rodents is activated at birth and is induced by glucocorticoids and cyclic AMP in the liver. Regulatory elements in a 10-kb fragment upstream of the mouse gene have been characterized. The promoter lacks TAATA and CCAAT consensus sequences and shows only extremely weak activity in transitory expression assays with phenylalanine hydroxylase-producing hepatoma cells. No key elements for regulation of promoter activity are localized within 2 kb of upstream sequences. However, a liver-specific DNase I-hypersensitive site at kb -3.5 comprises a tissue-specific and hormone-inducible enhancer. This enhancer contains multiple protein binding sites, including sites for ubiquitous factors (NF1 and AP1), the glucocorticoid receptor, and the hepatocyte-enriched transcription factors hepatocyte nuclear factor 1 (HNF1) and C/EBP. Mutation revealed that the last two sites are critical not only for basal activity but also for obtaining a maximal hormone response. Efficient transcription from the highly inducible promoter shows absolute dependence upon the enhancer at kb - 3.5, which in turn requires HNF1 and C/EBP as well as hormones. The regulatory region of the mouse phenylalanine hydroxylase gene differs totally from that of humans, even though the genes of both species are expressed essentially in the liver. Furthermore, the phenylalanine hydroxylase gene of mice shows an expression pattern very similar to those of the rodent tyrosine aminotransferase and phosphoenolpyruvate carboxykinase genes, yet each shows a different organization of its regulatory region.

Spontaneous apoptosis in a rat hepatoma cell line and its inhibition by dexamethasone

Cultures of dedifferentiated rat hepatoma Rab1-5-1 cells exhibit spontaneously a high level of mortality during the exponential growth phase. We demonstrate that these cells die by apoptosis, showing chromatin condensation and internucleosomal DNA fragmentation. Cells of the original H4II cell line and of its differentiated and dedifferentiated derivatives also die by apoptosis, but only in heavily confluent cultures. We evaluated mortality with time in Rab1-5-1 cultures by establishing growth curves, including quantification of floating cells, and conclude that up to half of the cells in a culture are lost to apoptosis. The production of apoptotic cells is abolished by the presence of 10(-6) M dexamethasone and this inhibition is reversible in 48 hours. Rab1-5-1 cells that spontaneously die by apoptosis with high frequency represent a novel model to investigate factors that regulate the spontaneous frequency of death, and to study the nature and the kinetics of commitment to the apoptotic pathway.

Molecular cloning and functional characterization of human lymphotactin

We describe the isolation of a cDNA that encodes human lymphotactin (Ltn), a new class of lymphocyte-specific chemokine. Human Ltn shows similarity to some members of the C-C chemokine family but has lost the first and third cysteine residues that are characteristic of the C-C and C-X-C chemokines. Ltn is chemotactic for lymphocytes but not for monocytes, a characteristic that makes it unique among chemokines. In addition, calcium flux desensitization studies indicate that Ltn uses a unique receptor. The human Ltn gene maps to a different chromosome than do the C-C and C-X-C chemokine families. Taken together, these characteristics indicate that Ltn is the first example of a new class of human chemokines with preferential effects on lymphocytes.

Molecular cloning and functional characterization of human lymphotactin

We describe the isolation of a cDNA that encodes human lymphotactin (Ltn), a new class of lymphocyte-specific chemokine. Human Ltn shows similarity to some members of the C-C chemokine family but has lost the first and third cysteine residues that are characteristic of the C-C and C-X-C chemokines. Ltn is chemotactic for lymphocytes but not for monocytes, a characteristic that makes it unique among chemokines. In addition, calcium flux desensitization studies indicate that Ltn uses a unique receptor. The human Ltn gene maps to a different chromosome than do the C-C and C-X-C chemokine families. Taken together, these characteristics indicate that Ltn is the first example of a new class of human chemokines with preferential effects on lymphocytes.

[Elevation of 7-dehydrocholesterol concentrations in serum and liver and pericentral peroxisome proliferation in hepatocytes of rats after inhibition of cholesterol biosynthesis by BM 15,766]

Sprague-Dawley rats of both sexes were treated for three months with BM 15,766, an inhibitor of cholesterol biosynthesis in conjunction with standard or high-fat and high-cholesterol diets. In serum and livers of all drug-treated rats lowered cholesterol concentration associated with an increase of 7-dehydrocholesterol (7-DHC) was found. Electron microscopy of the liver showed a distinct proliferation of peroxisomes and an increase of dumb-bell shaped mitochondria in the pericentral zone 3. Abnormal-shaped peroxisomes with DAB-negative loops attached to their membranes were found in the intermediate zone 2. These alterations were more accentuated in drug-treated rats fed standard diet, then in treated rats receiving a high-fat and high-cholesterol diet. The observations demonstrate, that the increase of 7-DHC is due to the inhibition of 7-DHC-delta 7-reductase by BM 15.766 and emphasize the zonal heterogeneity of hepatocytes. The relevance of these observations for the investigation of the human Smith-Lemli-Opitz syndrome, in which also decreased plasma-cholesterol levels and an increase of 7-DHC were reported, is discussed.

Response of the phosphoenolpyruvate carboxykinase gene to glucocorticoids depends on the integrity of the cAMP pathway

The phosphoenolpyruvate carboxykinase (PEPCK) gene is regulated at the transcriptional level by a variety of effectors in a tissue-specific fashion. In order to study the parameters involved in the tissue-specific hormonal regulation of the PEPCK gene, we have used a transient expression test in well-differentiated rat hepatoma cells as well as in dedifferentiated variants. In this test, the PEPCK promoter is induced by glucocorticoids in well-differentiated FGC4 cells, but not in H5 dedifferentiated variants, in spite of the presence in H5 cells of the glucocorticoid receptor. Study of the PEPCK promoter using electrophoretic mobility shift assays reveals binding sites for the liver-enriched transcription factors HNF1, vHNF1, HNF3, HNF4, and CAAT/enhancer binding protein members. Overexpression of the liver-enriched transcription factors absent in the dedifferentiated variants, such as HNF1 and HNF4, is not sufficient to restore glucocorticoid response of the PEPCK promoter in the variants. Moreover, systematic analysis of the PEPCK promoter reveals that the presence of a region covering a cAMP-responsive element (CRE1 at -80) and a CAAT box is necessary for full response of the PEPCK promoter to glucocorticoids in well-differentiated rat hepatoma cells. In a cotransfection test, overexpression of the regulatory subunit of protein kinase A (PKA), causing sequestering of PKA, abolishes the glucocorticoid response of the promoter in well-differentiated cells. On the other hand, in dedifferentiated variants, overexpression of the catalytic subunit of PKA restores the response to glucocorticoids. The action of PKA on the glucocorticoid response requires the presence of the CRE1 element and is promoter specific because it does not concern nonhepatic promoters such as the long terminal repeats of the mouse mammary tumor virus. These results suggest that the full response of the PEPCK promoter to glucocorticoids requires activation of another signal transduction pathway, the cAMP-mediated pathway.

Hepatocyte nuclear factor 3 is a major determinant of CYP2C6 promoter activity in hepatoma cells

Cytochrome P450 2C6 (CYP2C6) is a developmentally regulated, constitutively expressed form of rat liver microsomal cytochrome P450 that in the liver of adult male rats is induced to a limited extent by phenobarbital. The gene is not expressed at detectable levels in the lung, kidney, or brain. It is expressed and inducible by phenobarbital in differentiated Reuber hepatoma cells that express many hepatocyte-specific genes but not in dedifferentiated derivatives lacking the majority of hepatocyte-specific functions. A 505-base pair proximal segment of the CYP2C6 promoter is highly efficient in driving transcription of a linked chloramphenicol acetyltransferase reporter gene in the differentiated rat hepatoma cell line FGC4, is much less effective in a related dedifferentiated variant H5, and has no measurable activity in nonhepatic C33 human cervical carcinoma cells. The activity of the CYP2C6 promoter in the differentiated hepatoma cells is strongly dependent on hepatocyte nuclear factor (HNF)3, which acts at a complex site just upstream of the TATA motif. Transactivation experiments show that the D-site-binding protein (DBP) may also contribute to CYP2C6 promoter activity, via a site that is adjacent to the proximal HNF3 site. A substantial contribution to promoter activity by the base pair -505 to -316 segment is observed in FGC4 and H5 cells but not in HepG2 cells; deletion of this segment causes a marked diminution in promoter activity only in the former two cell lines. Although footprinting experiments have permitted the definition of three protein binding sites in this region (two HNF3 and one unidentified), mutation of these sites does not diminish promoter activity. The functionally important cis sequences in this region therefore remain to be defined. In HepG2 cells the distal region does not contribute to promoter activity. This most likely accounts for the low promoter activity in HepG2 and implies a deficiency in the relevant trans-acting factor(s).

Identification of polypeptides whose presence correlates with retention or loss of an albumin extinguisher chromosome in rat hepatoma-mouse L cell fibroblast microcell hybrids

The total protein content of a series of hybrids derived from the fusion of rat hepatoma cells with microcells of mouse L cell fibroblasts has been evaluated by two-dimensional electrophoresis. The parental rat hepatoma cells express a large set of hepatic functions, including the production of albumin. In the microcell hybrids containing chromosome M1 (marker 1) as the unique mouse chromosome, it has been previously shown that rat albumin production is selectively extinguished, and that this extinction is no longer observed when chromosome M1 is partially or completely lost. Our current results show that albumin-producing and -nonproducing microcell hybrids have very similar polypeptide patterns, although a few differences are detected and can be classified in coherent categories. One of these polypeptides is a fibroblast protein whose synthesis is maintained and strictly correlated with the albumin extinction phenotype. It thus represents a potential candidate for a negative regulator of albumin expression.

Constancy of expression of the protein kinase A regulatory subunit R1 alpha in hepatoma cell lines of different phenotypes

In somatic hybrids between fibroblast microcells and rat hepatoma cells, tissue-specific extinguisher 1 (TSE1), localized to mouse chromosome 11, extinguishes the expression of tyrosine aminotransferase and phospho(enol)pyruvate carboxykinase. Recently, it was demonstrated that TSE1 corresponds to R1 alpha, a regulatory subunit of protein kinase A. Here, we have analyzed whether R1 alpha could play a role in differentiation of the hepatocyte. It is known that the TSE1/R1 alpha target genes belong to the group of neonatal functions that are repressed until birth. High expression of R1 alpha characterizes fetal-type BW1J hepatoma cells in which the neonatal target genes are silent. This R1 alpha is active in trans to extinguish these genes in hybrids between BW1J and Fao adult-type rat hepatoma cells. Reexpression of the target genes is correlated with loss of R1 alpha and/or overexpression of the mRNA for the hepatocyte-enriched transcription factors HNF4 and HNF3 alpha. Phenylalanine hydroxylase is shown to be another function negatively regulated by R1 alpha. In BW cells in which expression of phenylalanine hydroxylase has been activated (after either 5-aza-cytidine treatment or transfection with genomic DNA from adult-type hepatoma cells), no down-regulation of R1 alpha expression occurs: an independent mechanism overcomes R1 alpha repression. Finally, dedifferentiated derivatives of the adult-type rat hepatoma cells express neither the R1 alpha target genes nor the R1 alpha gene itself. Thus, in three different situations in which modulation of R1 alpha expression could be anticipated, it fails to occur.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of mastectomy in patients with stage I-II breast cancer presenting with gross multifocal or multicentric disease or diffuse microcalcifications

PURPOSE

Women with Stage I-II invasive breast cancer who present with gross multicentric disease or diffuse microcalcifications have a significant risk of breast recurrence when treated with conservative surgery and radiation. The purpose of this report is to present the results of mastectomy in this group of patients.

METHODS AND MATERIALS

Between 1982 and 1989, 88 patients with clinical Stage I-II breast cancer who presented with clinical and mammographic evidence of gross multicentric disease or diffuse microcalcifications underwent modified radical mastectomy. Median followup was 4 years for the 57 patients with gross multicentric disease and 5.6 years for 31 patients with diffuse microcalcifications. At the time of mastectomy, 42% of patients were found to have positive axillary nodes. Following mastectomy, 15 patients received post mastectomy radiation and 35 patients received adjuvant systemic chemotherapy.

RESULTS

When compared to a group of 1295 patients with unifocal, Stage I-II breast cancer, treated with conservative surgery and radiation during the same time period, patients with gross multicentric disease and diffuse microcalcifications had a significantly higher incidence of > or = 4 positive nodes, patients with gross multicentric disease had a lower incidence of positive resection margins following mastectomy and patients with diffuse microcalcifications were younger. The 5-year actuarial risk of an isolated local-regional recurrence was 8% for patients with gross multicentric disease or diffuse microcalcifications and 7% for patients with unifocal disease. Patients with gross multicentric disease or diffuse microcalcifications and > or = 4 positive axillary nodes who did not receive post mastectomy radiation had an increased risk for local regional recurrence. There were no significant differences in the 5-year actuarial overall or relapse-free survival (88% and 73% gross multicentric disease, 97% and 86% diffuse microcalcifications and 90% and 79% unifocal disease), freedom from distant metastasis (76% gross multicentric disease, 90% diffuse microcalcifications, 86% unifocal disease) or incidence of contralateral breast cancer (10% gross multicentric disease, 13% diffuse microcalcifications, 8% unifocal disease) among the three groups.

CONCLUSION

The present study demonstrates no increased risk of local-regional recurrence in patients with gross multicentric disease or diffuse microcalcifications undergoing mastectomy in contrast to the increased risk of breast recurrence in patients with gross multicentric disease undergoing conservative surgery and radiation. Indications for post mastectomy radiation include > or = 4 positive nodes or close or positive surgical margins. Despite a significantly higher incidence of > or = 4 positive nodes, patients with gross multicentric disease and diffuse microcalcifications have a 5-year actuarial overall and relapse-free survival comparable to a group of patients with unifocal disease treated with conservative surgery and radiation.

The phenobarbital-induced transcriptional activation of cytochrome P-450 genes is blocked by the glucocorticoid-progesterone antagonist RU486

Several of the hepatic microsomal cytochromes P450 can be induced by various drugs and xenobiotics, among them the barbiturate phenobarbital. Rat hepatoma cells (Fao and its derivatives) respond to phenobarbital or dexamethasone treatment with an increased accumulation of CYP2C6 mRNA and thus provide a culture system to investigate the mechanisms involved. Examination of the kinetics of CYP2C6 mRNA induction revealed that the response to dexamethasone is rapid, whereas induction by phenobarbital occurs only slowly after an 8-10-hr lag. Run-on transcription measurements demonstrated that phenobarbital treatment led to a 3-4-fold increase in CYP2C6 gene transcription. Surprisingly, induction by phenobarbital of both accumulation of CYP2C6 mRNA and transcription of the gene was blocked by the antiprogestin-antiglucocorticoid RU486, suggesting the involvement of a steroid receptor in the induction process. Transfection of promoter constructs containing a reporter gene whose expression is driven by a 1.4-kilobase 5' flanking segment of the CYP2B1 or CYP2B2 genes, which are highly inducible by phenobarbital in rat liver, led to > 3-fold increases in reporter gene activity in the presence of the drug. Again, phenobarbital induction was prevented by RU486. The RU486 inhibition of the phenobarbital induction of both the endogenous CPY2C6 gene and the transfected CYP2B1 and CYP2B2 promoter constructs leads us to propose a model whereby the drug acts indirectly to cause the accumulation of an endogenous steroid, and this molecule, acting via its receptor, would be the direct inducer of cytochromes P450. Whether or not this model proves to be correct, the results presented here provide the first evidence of the involvement of a steroid receptor in phenobarbital induction.

Regulation of albumin gene expression in hepatoma cells of fetal phenotype: dominant inhibition of HNF1 function and role of ubiquitous transcription factors

Two widely used hepatoma cell lines, mouse BW1J and human HepG2, express gene products characteristic of fetal hepatocytes, including serum albumin, whereas reporter genes driven by the albumin promoter are expressed at very low levels compared with highly differentiated hepatoma cells. We have investigated the low albumin promoter activity in BW1J cells to understand differences in liver gene regulation between fetal and adult cells. Addition of the albumin upstream enhancer, or any other fragment of the albumin gene, failed to modify expression of the transfected promoter in BW1J cells. Analysis of cis elements of the albumin promoter showed that, in contrast to highly differentiated H4II cells, in BW1J cells the activity largely depends on ubiquitous transcription factors. Both BW1J and HepG2 cells produce the liver-enriched transcription factor HNF1; dimerization and DNA binding properties are identical to those of liver HNF1, yet the protein fails to show the anticipated transcriptional stimulatory activity. A transfected HNF1 expression vector strongly trans-activates the albumin promoter in HepG2 but only weakly in BW1J cells, and in hybrids (BW1J x Fao), inefficient HNF1 function is dominant. We conclude that hepatoma cells of the fetal phenotype are deficient in the use of HNF1 to drive transcription of the albumin gene and that they harbor a dominant modulator of HNF1 function.

Cell phenotype, binding affinity and promoter structure modulate transactivation by HNF1 and LAP

To evaluate the importance of the transcription factors known to bind to the albumin promoter as well as the parameters involved in their activity, we have used cotransfections with an albumin promoter-cat plasmid combined with expression vectors driving the expression of cDNAs coding for liver-enriched factors known to interact with this promoter. We describe the characteristics of a set of clones of hepatic origin: well differentiated, partial variants or pleiotropic dedifferentiated variants. These lines have been characterized for the accumulation of RNAs corresponding to each of the albumin promoter-binding factors. Only HNF1, and to a lesser extent C/EBP, show differences depending upon the differentiation state of the cells. Overexpression of exogenous HNF1 in these cells reveals that this factor is able to transactivate the albumin promoter only in variant cells where the endogenous protein is limiting. By contrast, if the HNF1-binding site is of weak affinity, overexpression of exogenous HNF1 stimulates the albumin promoter even in the HNF1-rich differentiated cells. Overexpression of exogenous LAP strongly transactivates an artificial promoter containing one LAP-binding site, but surprisingly in all the cell lines, it has little effect upon the albumin promoter. These results demonstrate that the transactivation potential of a given transcription factor depends on the degree of differentiation of the recipient cells, on the promoter structure, and on the affinity of the binding site for this factor.

Assignment of the rat genes coding for alpha 1-antitrypsin (PI), phosphoenolpyruvate carboxykinase (PEPCK), alcohol dehydrogenase (ADH), and fructose-1,6-bisphosphatase (FDP)

The chromosomal localization of four genes which are expressed mainly in the liver has been undertaken for the rat. Using a panel of hybrid clones segregating rat chromosomes, and Southern blot analysis, alpha 1-AT (PI), PEPCK, ADH and FDP are assigned to rat Chromosomes (Chr) 6, 3, 2 and 17, respectively. Groups of synteny among rat, mouse and human species are discussed in relationship to the new assignments.

Breast recurrence and survival related to primary tumor location in patients undergoing conservative surgery and radiation for early-stage breast cancer

Between 1977 and 1986, 886 pts with Stage I and II breast cancer underwent excisional biopsy, axillary dissection and radiation. Median follow-up was 5 years (range 2 months-13 years). The patients were divided into four groups according to the primary tumor location: 1) outer (495 patients), 2) inner (202 patients), 3) central (119 patients), and 4) subareolar (70 patients). Subareolar tumors were defined as those immediately beneath the nipple-areolar complex or within 2 cm of the areolar margin. The comparability of the groups was assed in terms of clinical T stage, patient age, histology, final pathologic margin status, estrogen and progesterone receptor status, pathologic nodal status, and use of adjuvant chemotherapy. There were no significant differences among the four groups in the distribution of these factors except for the pathologic nodal status (outer 38% positive nodes, inner 24%, central 23%, subareolar 31%) p = .0004. There were no significant differences in 5 year actuarial overall survival (91% vs 86% vs 92% vs 91%, p = .34), relapse-free (75% vs 74% vs 80% vs 79%, p = .77), or NED survival (82% vs 78% vs 87% vs 84%, p = .29) for the four groups. A separate analysis for pathologic node negative and node positive patients revealed similar findings. For node-negative patients, the 5 year actuarial overall survival was 93% vs 88% vs 94% vs 91% (p = .20), the relapse-free survival was 78% vs 76% vs 82% vs 79% (p = .49), and the NED survival was 86% vs 81% vs 88% vs 86% (p = .46). For node-positive patients, the 5 year actuarial overall survival was 87% vs 82% vs 84% vs 90% (p = .59), relapse-free survival was 69% vs 66% vs 77% vs 80% (p = .78), and NED survival was 75% vs 68% vs 85% vs 80% (p = .66). Patterns of first failure were also not significantly different among the four groups: local only first failure (7% vs 4% vs 5% vs 8%, p = .49), any local first failure, i.e., +/- simultaneous distant metastases (8% vs 5% vs 5% vs 9%, p = .61), regional only (2% vs 1% 1% vs 0%, p = .65), any regional (4% vs 3% vs 3% vs 3%), or distant metastases (11% vs 17% vs 9% vs 10%, p = .16). A separate analysis of node negative and node positive patients revealed similar findings.(ABSTRACT TRUNCATED AT 400 WORDS)

Microinvasive ductal carcinoma of the breast treated with breast-conserving surgery and definitive irradiation

An analysis was performed of 39 consecutive women with microinvasive ductal carcinoma of the breast treated with breast-conserving surgery and definitive irradiation during the period 1977 to 1988. Microinvasive ductal carcinoma was defined as predominantly intraductal carcinoma with microscopic or early invasion. Surgical treatment of the primary tumor included excisional biopsy or wide resection. Axillary lymph node staging showed that 37 patients were pathologically node negative and two patients were pathologically node positive, each with only one positive lymph node. The median follow-up was 55 months (mean = 65 months; range = 25-135 months). The 5-year actuarial rate of overall and cause-specific survival were both 97%. The 5-year actuarial rate of freedom from distant metastases was 93%. Nine patients developed a recurrence in the breast; eight of the nine patients had isolated local only first failures, and one of the nine patients had a local recurrence simultaneously with distant metastases. The median time to local failure was 42 months (mean = 53 months; range = 20-116 months). Of the eight patients with local only first failure, seven patients have been salvaged with further treatment and remain free of disease at the time of last follow-up, and one patient has died of subsequent distant metastatic disease. Median follow-up after salvage treatment was 29 months (mean = 27 months; range = 0-54 months). Comparison of the patients with microinvasive ductal carcinoma with two control groups of intraductal carcinoma and invasive ductal carcinoma was performed. Although the rate of local failure was significantly higher for patients with microinvasive ductal carcinoma as compared to the two control groups, the rates of survival and freedom from distant metastases for patients with microinvasive ductal carcinoma were intermediate to the two control groups. Because of the high rates of survival and freedom from distant metastases and because of the ability to salvage patients with local recurrence, breast-conserving surgery and definitive irradiation should continue to be considered as an alternative to mastectomy for appropriately selected and staged patients with microinvasive ductal carcinoma of the breast.